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HEVEA  BRASILIENSIS 


PARA  RUBBER 


HERBERT   WRIGHT,  asso«s*  R.C.5..  f.l.s. 


CORNELL 

UNIVERSITY 

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PARA   RUBBER. 


(07T./3 


PREFACE   TO    THE    FOURTH   EDITION. 


While  writing  this  edition   I   have  been   greatly  impressed 
by  the  changes  which,  in  quite  recent  times,  have  come  over 
the    plantation    and    crude    rubber   industry.     At    the    time    of 
writing  the  previous  editions  in  1905,  1906,  and  1908  respectively, 
I  had  the  impression  that  the  development  of  plantations  was,  in 
many    details,    in    quite    an    experimental    phase.     To-day    this 
idea   must   be    almost   entirely   abandoned.     The   cultivation   of 
rubber  trees  has   proved   itself  to  be  equal  to,  if  not  more  im- 
portant than,  that  of  any  other  plant  grown  in  the  tropical  zone. 
Hevea  brasiliensis  has  now  been  successfully  grown  throughout 
the   Indo-Malayan   region,   in   tropical    America    (including    the 
West  Indies)  and  tropical  Africa.     It  flourishes  on  rocky  hillsides, 
fiat  alluvial  plains,  wet  soil,  and  dry  land,  at  all  altitudes  from 
sea-level  to  3,000  feet,  and  is  now  recognised  as  the  most  hardy  and 
profitable    rubber-yielding    species    under    cultivation.     It    has 
continued  to  grow  for  over  one-third  of  a  century- in  Ceylon  and 
Malaya  and  one  of  the  oldest  specimens  recently  yielded  160  lb.  of 
dry  rubber  in  two  years.     The  crops  from  cultivated  trees  and 
the   anticipated  yields  have  so  impressed  various  governments 
that  many  of  them  have  decided  to  effect  a  radical  change  in 
their  agricultural  policy.     Those  Governments,  which  for  many 
years  have  relied  upon  large  revenues  from  Brazilian  and  African 
forests  have,  though  at  a  very  late  hour,  seen  the  necessity  of 
lowering    export    duties,    subsidising    plantation    developments, 
and  encouraging  the  use  of  scientific  methods   and  up-to-date 
machinery  in  the  collection  and  preparation  of  raw  rubber.     This 
of  course    means  a  continuation  of  supplies  and  keener  competi- 
■  tion  at  some  future  period.     While  the  growth  of  the  Eastern 
plantation    industry    has    led    countries,    previously    dependent 
upon  wild  rubber,  to  protect  old  and  foster  new  sources  of  supply, 
other  countries,  especially  Ceylon,  Borneo,  the  Federated  Malay 
States  and  the  Straits  Settlements,  have  already  reaped  consider- 
able financial  benefit  from  the  sale  of  land  and  new  taxation. 
The  new  industry  has  not  only  changed  the  agricultural  policies 
of  foreign  governments  and  general  trading  relationships,  but  it 
has  also  resulted  in  the  opening  up  of  land  and  the  distribution 
and  employment  of  large  native  populations  in  vast  forest  areas 
previously  of  no  importance   to   the   commercial  world.     What, 
in  point  of  productivity,   the  planting  of  one  million  acres  of 
rubber  trees  will  mean,  can  only    be    manifest    some  six  years 


vi  PREFACE. 

hence,  but  there  is  ample  evidence  that  it  will  materially  affect 
many  departments  of  commerce  except  some  unforeseen  disaster 
overtakes  plantations.  An  annual  yield  of  100,000  tons  from 
Eastern  plantations  will  assuredly  have  its  influence  in  many 
directions. 

.\nother  feature,  of  more  than  passing  importance,  is  the 
wide-spread  recognition  gained  by  this  new  agricultural  develop- 
ment during  the  last  few  years.  The  plantations  in  the  East 
alone  have  even  now  drawn  approximately  £100,000,000  from 
the  financial  houses  of  Europe,  and  already  there  are  signs  of 
changes  in  the  centres  of  distribution  of  crude  rubber,  which 
will  become  better  defined  as  new  supplies  from  the  various 
Eastern  ports  increase.  The  security  presented  in  well-managed 
plantations  has  drawn  into  the  investor's  list  individuals  from 
every  class,  from  royal  blood  to  the  peasant.  The  press  has, 
in  almost  every  civilised  country,  recognized  the  commercial 
aspect  ;  newspapers,  magazines,  and  technical  journals  have 
found  it  advisable  to  chronicle  the  trend  of  events  in  relation  to 
the  raw  and  manufactured  product. 

Even  our  learned  societies,  colleges,  and  universities  have 
realized  that  in  this  new  line  of  tropical  agriculture  there  is  some- 
thing worthy  of  being  not  only  recognized,  but  maintained  and 
protected.  The  enterprise,  being  largely  British,  means  a  great 
deal  to  this  country  ;  considerably  more  than  half  the  world's 
total  planted  acreage  is  in  British  possessions.  Our  universities 
recognise  that  the  success  of  every  tropical  cultivation  is  dependent, 
in  the  long  run,  on  the  relative  immunity  from  diseases  and  pests 
which  the  plants  enjoy  ;  they  also  know  that  extensive  and  con- 
tiguous areas  under  the  same  species  present  ideal  conditions 
for  the  spread  of  menacing  epidemics  among  plants.  The  active 
steps  taken  by  the  Imperial  College  of  Science  and  Technology' 
in  creating  a  chair  of  plant  pathology,  in  order  that  men  may  be 
thoroughly  trained  in  all  that  pertains  to  plant  diseases  in  the 
tropics  and  elsewhere,  is  admittedly  one  of  prime  importance. 
That  the  rubber  plantation  industry  should  have  played  a  part 
in  encouraging  its  immediate  inauguration  should  give  satisfac- 
tion to  all  who  have  the  permanency  of  plantations  in  view. 
Already  trained  mycologists  and  chemists  have  been  sent  to  the 
East  to  render  every  possible  assistance  to  planters  on  the  spot. 
Diseases  and  pests  will,  like  labour  troubles,  always  be  with  us  ; 
they  can,  however,  be  kept  in  check  if  trained  men  are  available 
and  every  effort  is  made  to  promptly  deal  with  them  immediately 
they  make  their  appearance.  It  must  be  admitted  that  to  the 
government  of  this  country  our  thanks  are  due  for  having  secured, 
on  their  own  initiative,  the  original  supplies  of  rubber  plants 
from  tropical  America  ;  it  is,  perhaps,  not  too  much  to  hope  that 
they  will  now  spare  no  efforts  to  protect  an  industry  which  affects 
thousands  of  their  people,  and  on  which  commerce  in  every 
civilised  land  is,  to  a  small  or  large  extent,  dependent. 


PREFACE.  vii 

As  far  as  the  estates  are  concerned  there  has,  in  the  past 
few  years,  been  marked  progress  in  the  methods  of  tapping, 
■coagulating,  washing,  drying,  and  packing  of  rubber.  While 
some  departments  of  estate  work  are  still,  in  part,  of  an  ex- 
perimental nature,  improvements  have  been,  and  are  still  being, 
effected.  The  greatest  progress  has,  I  think,  been  in  the  systems 
of  tapping  and  in  the  yields  obtained.  When  this  edition  was 
decided  upon  I  issued  printed  forms  to  all  managers  of  Hevea 
plantations,  and  directors  of  rubber  companies,  soliciting  definite 
statements  regarding  the  methods  of  tapping  trees  of  various 
ages,  the  thickness  of  bark  shavings,  the  kind  of  knife  preferred 
and  the  yields  from  trees  varying  in  age  from  three  to  twenty- 
five  years.  It  is  owing  to  the  very  willing  help  rendered  by  the 
responsible  officers  of  the  various  estates  and  companies  in  Ceylon, 
Malaya,  and  the  Dutch  East  Indies  that  the  chapters  dealing 
with  these  subjects  have  been  written. 

I  hope  that  the  low  average  yield  obtained  on  some  estates 
and  in  certain  countries  will  lead  to  a  much  closer  investigation 
as  to  the  causes.  Poor  soil,  overcrowding  of  the  plantation 
and  weeds  are  largely  responsible  for  the  low  average  yields  herein 
•quoted  from  particular  countries  or  estates ;  the  first  can  be 
remedied  by  proper  tillage  and  manuring,  the  others  by  better 
financial  and  estate  management.  It  must  also  be  borne  in  mind 
that  low  average  yields  may,  to  a  very  large  extent,  be  com- 
pensated for  by  the  excellence  of  the  management ;  the  countries 
of  highest  average  yield  per  tree  are  those  where  labour  and 
-staff  expenses  are  comparatively  high. 

In  the  length  of  time  allowed  for  renewal  of  bark  there  has 
been  very  little  change,  though  there  is  still  a  widespread  desire 
to  tap  the  newly-formed  tissue  as  soon  as  its  thickness  is  equal 
to  that  of  the  old  bark,  and  consequently  a  tendency  to  adopt 
a  three-year  cycle  instead  of  one  of  four  years.  Though  much 
depends  upon  the  rate  of  growth,  I  am,  in  general,  inclined  to  the 
view  that  it  would  be  wiser  to  lengthen  rather  than  shorten  the 
iour-year  interval  which  I  have  up  to  the  present  advocated. 

It  has  been  found  impossible  to  keep  to  the  plan  adopted 
in  previous  editions  ;  the  growth  of  the  industry  and  the  estate 
improvements  effected  have  necessitated  my  taking  a  much 
wider  view  of  the  whole  subject,  and  in  fact  re-writing  original 
■chapters  and  adding  many  new  ones.  My  information  has  been 
drawn  from  numerous  sources,  including  estate  documents 
connected  with  companies  in  which  I  am  particularly  interested, 
and  g'eneral  literature  on  the  subject.  I  have  not  hesitated  to 
use  matter  appearing  in  the  India -Rubber  Journal,  and  my 
■other  books  bearing  on  rubber  cultivation. 

In  the  preparation  of  this  edition  I  have  received  valuable 
assistance  from  many  friends.  Above  all,  I  must  acknowledge 
Mr.  W.  T.  Gibson,  A.R.C.Sc,  for  his  valuable  assistance  from 
the  beginning  to  the  end  of  this  work,  and  especially  for  the 


vni  PREFACE. 

various  statistics  and  the  detailed  index  he  has  compiled.  Had 
I  not  been  able  to  obtain  his  services  I  fear  that  the  publication 
of  this  edition  would  have  been  long  delayed.  I  have  also  to 
thank  Dr.  P.  Schidrowitz  for  suggestions  incorporated  in  the 
chapter  dealing  with  the  chemistry  and  testing  of  rubber  ;  Dr.  D. 
Spence  for  his  notes  on  proteins  ;  Mr.  Tabor  for  the  drawings 
showing  the  anatomy  of  the  stem  of  Hevea  brasiliensis  ;  Mr. 
Kurt  Pfleiderer  for  reading  the  manuscript  of  the  chapter  on 
washing  of  rubber ;  the  managers,  directors,  and  secretaries 
of  plantation  companies  for  furnishing  me  with  up-to-date 
information  ;  and  the  numerous  firms  who  have  so  generously 
supplied  me  with  illustrations. 

H.W. 

March  8th,  1912, 


CONTENTS 


•       CHAPTER    I. 

The  History  of  Para  Rubber. 

Columbus  and  Haiti  gum  balls — References  by  Valdez,  Anghiera  and 
Torquemada — Origin  of  the  name  indiarubber — Discovery  of  vulcanization — 
First  account  of  Hevea  species — Early  use  of  rubber — Various  rubbers  from 
species  of  Hevea — Trade  name,  geography  and  botanical  origin  of  Para  grades — 
History  of  Para  exports  from  1827  to  191  o — West  African  crops — Wild  rubber 
developments — Importance  of  wild  rubber  supplies — Changes  in  wild  rubber 
grades — Differences  between  wild  and  plantation  areas — Future  supplies  from 
Brazil — Government  encouraging  plantations  in  Brazil — Supervision  and 
protection  of  trees  in  Brazil — Government  financially  assisting  planters  in 
Brazil — Proposals  by  the  Acre  Congress — Recommendations  by  the  Manaos 
Congress — African  plantation  developments — Congo  plantations — Belgians 
agree  to  plant  specified  acreage  annually — Plantation  progress  in  Central, 
West  and  East  Africa — Equivalent  in  planted  acreage  of  total  Brazilian  crops — 
Evolution  of  Eastern  planted  acreage — Growth  of  Brazilian  and  plantation 
supplies  :  a  comparison — Exports  from  Malaya  during  1906,  1907,  1908,  1909, 
igio — Distribution  of  Malayan  rubber — Estimated  output  by  Sir  John 
Anderson  from  Malay  six  years  hence — H.  K.  Rutherford's  estimated  output 
from  the  Federated  Malay  States  during  next  six  years — Exports  from  Ceylon — 
Distribution  of  Ceylon  rubber — Estimated  crops  from  Ceylon — Outturn  of 
rubber  by  the  larger  companies — Can  plantations  treble  the  Amazon  crop — 
History  of  Para  rubber  prices — 2S.  7d.  in  1891  to  12s.  gd.  in  1910 — High 
prices  and  increased  supplies — Prices  and  premium  for  plantation  rubber — 
Effect  of  high  prices  on  future  plantation  industry  and  Brazilian  supplies — 
Potentialities  of  Eastern  industry — Financial  support  to  plantation  industry — 
Capital  involved  in  1907,  1908,  1909,  1910 — -^90,000,000  par  value  for  planta- 
tions in  United  Kingdom.  1-24 

CHAPTER   II. 

History  of  Rubber  Plantations. 

Plantations  recommended  by  Hancock  in  1834 — Distribution  of  rubber 
plants  from  Kew — Ceylon,  Singapore,  and  India  original  centres — Characters  of 
parent  plants  from,  and  soil  in,  the  Amazon  valley — Collins  procures  seeds  in 
1873 — Seeds  from  Wickham  in  1876 — Arrival  of  Wickham's  seeds  at  Kew —  . 
Plants  from  Cross  in  1876 — Transmission  to  Ceylon — Propagation  from 
cuttings — First  seeds  in  Ceylon — Distribution  of  seeds  within  the  tropics — 
Distribution  from  and  between  Singapore  and  Ceylon — Distribution  of  various 
rubber  plants  in  Malaya  and  India — Seeding  trees  in  tropical  possessions — 
Rubber  plants  from  Kew — Hevea  seeds  sent  from  Ceylon  to  Brazil — Characters 
of  present  plants  in  Amazon — Labour  costs  and  planted  acreages — Early 
history  of  cultivation,  preparation,  and  yields  in  Ceylon — Hevea  in  Ceylon — 
Cultivation  and  exports  from  1890  to  1910 — Area  originally  described  as 
suitable  for  rubber  in  Ceylon — Acreage  now  under  rubber — Principal  rubber 
districts  in  Ceylon — Hevea  in  South  India  and  Burmah — Acreage  and  number 
of  Hevea  trees  in  Malaya  in  1897,  1902,  1906,  to  1910 — Distribution  of  acreage 
and  number  of  Hevea  trees  in  Federated  Malay  States,  Straits  Settlements, 
Johore,  etc. — Rubber  in  Cochin-China  and  Annam — In  Siam — Acreages  in 
Sumatra — In  Java — In  British  Borneo — New  Guinea  and  Queensland — 
Samoan  rubber  developments — Rubber  in  Hawaii,  Fiji,  Solomon  Islands — 
Seychelles — Rubber  cultivation  in  the  Philippines — Hevea  rubber  in  Africa — 
Area  in  Liberia — Possibilities  in  Nigeria — Gold  Coast — Cultivation  in  Ashanti 
— Central  Africa — East  Africa — Planting  in  Nyasaland — Mauritius — Rubber 
in  the  West  Indies — British  Guiana — Rubber  in  Dutch  Guiana — Central 
America — Projected  rubber  planting  in  Russia  ! — The  World's  acreage 
in  1912.  25-45 


X  CONTENTS. 

CHAPTER  III. 
Botanical  Sources  of  Rubber. 
Relative  importance  of  tropical  America,  Africa,  and  Asia  as  sources  of 
rubber — Botanical  sources  of  rubber — Natural  orders  of  plants  yielding 
caoutchouc — Euphorbiaceae — Apocynaceae — Urticacese — Asclepiadaceae-  Com  • 
positas  —  LobeUaceee  —  Geographical  distribution  of  important  rubber 
plants — Indigenous  and  introduced  plants — Trees,  shrubs,  and  climbers — Im- 
portant generic  sources — Rubber-yielding  species — Laticiferous  and  caout- 
chouc-yielding plants — Hevea  Brasiliensis — High  percentage  of  caoutchouc — 
Botanical  characteristics — Other  species  of  Hevea,  l4ieir  distribution  and 
value — Species  of  Hevea  tapped  in  Peru,  Bolivia,  Guiana — Foliar  period- 
icities of  Hevea  brasiliensis — Fruit  periodicities  in  Singapore — In  Ceylon  and 
elsewhere — Laticiferous  system  in  various  plants — Hevea  brasiliensis,  structure 
of  stem,  laticiferous  system — How  latex  channels  are  formed — Formation 
of  rubber  in  situ — Variability  of  laticiferous  system  in  Hevea — Functions  of 
latex — Storing  water  and  as  waste  product — Protection  against  pests — Latex 
as  reserve  food — Observations  of  Warming,  Freeman,  Parkin,  Ridley,  Lloyd, 
Sachs,  Haberlandt,  Petch,  and  Spence — Difficulty  in  determining  function 
of  latex,  where  bark  excised — Illustrations  showing  the  anatomy  of,  and 
distribution  of,  laticifers  in  Hevea  brasiliensis.  46—64 

CHAPTER  IV. 
Climatic  Conditions  for  Hevea  Brasiliensis. 
Climate  in  Brazil — Monthly  rainfall  at  Manaos,  Ceara  and  Para — Climate 
in  Ceylon — Climate  in  South  India — Cochin — Federated  Malay  States — Rain- 
fall at  Perak,  Selangor,  Negri  Sembilan,  Kelantan — Singapore,  Penang, 
Malacca — Climate  in  Sumatra — Rainfall  on  well-known  Langkat,  Serdang, 
and  Bandar  estates — Climate  in  Java — Buitenzorg,  East  Java — Conditions  in 
Borneo — New  Guinea — Climate  in  Cochin-China — Climate  in  Seychelles, 
Fiji  Islands  and  Philippines — Climate  in  Samoa — Chmate  in  Africa — Rain- 
fall at  Gold  Coast  and  in  Nigeria — Togo  and  East  Africa — Dry  districts  and 
irrigation — Climate  in  Uganda — West  Indies,  Trinidad,  Grenada,  Jamaica — 
Climate  in  British  Guiana — Surinam.  65-77 

CHAPTER  V. 
Rate  of  Growth  of  Hevea  Brasiliensis. 
Rate  of  growth  of  stem — Girth  of  trees  at  Henaratgoda  from  1876  to  1905 
— Girth  of  Peradeniya  trees  29  years  old — Size  of  trees  at  Edangoda  and  Yatti- 
pawa — Rate  of  growth  in  parts  of  Ceylon  on  estates  interplanted  with  other 
products — Kegalle,  Knuckles,  Sabaragamuwa,  Katugastota,  Nilambe,  Neboda, 
Vogan — Census  of  estates  in  Ceylon — Growth  in  India  and  Burmah — Nilambur 
,  — Cochin — Shevaroys — Mergui — Growth  in  Malaya — Singapore — Largest  trees 
in'  Malaya — Growth  in  Selangor  and  Malacca — Growth  on  Jeram  estate — 
Growth  in  Perak — Growth  in  other  parts  of  Malaya — Growth  in  Java — 
Binangoen — East  Java — West  Java — Sampang  Peundeni — Growth  in  Sumatra 
— Suggestions  regarding  rate  of  growth  in  Sumatra — Measurements  of  trees  in 
Bandar  Langkat,  Siantar  and  Tamiang  districts — Growth  in  British  Borneo — 
Growth  in  Papua  and  Queensland — Fiji,  Hawaii  and  Indo-China — Rate  of 
growth  in  Africa — Congo — Gold  Coast  (Tarkwa,  Aburi,  Coomassie 
and  Axim) — Growth  in  Uganda — Nyasaland — Slow  growth  in  West  Indies — 
Surinam — Growth  of  the  stem  under  special  circumstances — Rate  of  growt 
under  forest  conditions  in  Singapore — Influence  of  elevation  and  age  on  rate 
of  growth — Girth  increases  per  acre — Census  of  trees — Ryan's  calliper — 
Burgess's  method  of  measuring  trees — Rate  of  growth  of  foliage  in  Ceylon 
districts — Rate  of  growth  of  root  system.  78-99 

CHAPTER      VI. 
Planting  Operations  and  Methods  of  Cultivation. 
Diversity   of  plantation  methods — Cultivation  of   Hevea  in   Malaya — 
Methods  of  cultivation  in  Ceylon,  South  India,  Java,  and  Sumatra — Shade 
in  Java  and  Malaya — Wind  and  damage  done  thereby — Wind  belts — Forestry 
on  rubber  estates — Plant  selection  for  Hevea — Habit  of  trees  and  yield — 
Artificial  pollination — Selection  of  seed  parents  on  estates — Selection  by 
chemical  method — Selection  by  propagating  from  cuttings — Selection  during 


CONTENTS.  xi 

transplanting — Methods  of  germination  and  planting — Selecting  and  manuring 
nursery  beds — Position  of  seeds  in  nursery  beds — Nursery  stumps — Trans- 
planting— Basket  plants — Clearing  operations — Removal  of  timber — Timber 
on  secondary  and  lalang  clearings — Uprooting  tree  stumps — Fencing  on 
estates — Draining — Terracing — Silt  traps — Holing  and  filling — Distance — 
Table  of  numbers  per  acre  and  planted  distances — Numbers  of  trees  per  acre  at 
specified  age  —  Hexagonal  planting  —  Diversity  of  opinion — Planting 
distance  in  Ceylon — Distance  and  checldng  of  growth — Results  in  Ceylon  and 
Malaya — Definition  of  close  planting  and  wide  planting — Advantages  and 
disadvantages  of  close  planting — Distance  required  by  tapped  trees — Original 
and  permanent  distance — Thinning  out — Gallagher  and  Carruthers — Thinning- 
out  in  Klang — Close  planting  and  available  tapping  area  in  early  stages — 
Personal  views  on  distance  and  methods  to  be  adopted — Pruning  trees — 
When  pruning  experiments  may  be  tried — Dimensions  of  straight-stemmed 
and  forked  trees — Some  experiments  in  pruning — Increase  in  girth  of  forked 
trees  in  Ceylon,  Africa,  and  India — Some  opinions  of  pruning — Weeding — Cost 
•of  weeding — Alternative  methods — System  in  clean-weeding — Clean-weeding 
generally  the  best — Cicely  estate  and  weeding — Cultivation  of  weed  killers — 
Effect  of  weeds  on  growth  of  Hevea — Lalang — Cost  of  eradication  by  spraying 
— Changkoling — Disc  harrow — Root  pruning.  100-134 

CHAPTER  VII. 
Cultivation  of  Catch  and  Intercrops. 
Adaptability  of  Hevea  brasiliensis — Advantages  and  disadvantages  of 
subsidiary  crops — Intercrops  and  reduction  of  loss  through  diseases — Financial 
■considerations — Future  importance  of  intercrops  of  coffee,  tea  and  cacao — 
Intercrops  in  Ceylon  and  South  India — Catch  crops  in  Malaya — Intercrops 
in  Sumatra — Intercrops  in  Java — Effect  of  rubber  on  other  products — 
Planting  distance  when  intercrops  grown — Inter  and  catch-crops  and  annual 
leaf- fall — Catch  crops — Lemon  grass — Citronella — Gambler — Ipecacuanha — 
Ground-nuts — Tapioca — Cotton — Manila  hemp — Indian  corn — Chillies — Pine- 
apples— Tobacco — Sugar — Bananas  —  Indigo — Intercrops — Tea — Camphor — 
-Coca — Cacao — Coffee — Robusta  coffee  and  Hevea  in  Java.  135-148 

CHAPTER  VIII. 
Hevea  Rubber  Soils  and  Manuring. 
Hevea  soils  in  South  America — Where  Hevea  thrives  on  the  Amazon — 
Wickham's  views  challenged — Opposing  statements  of  its  preference  for 
wet  or  for  drained  soils — Heyea  not  constructed  for  swamps — Good  growth  in 
unpromising  soils — Hevea  soils  in  Ceylon — Cabooky,  alluvial,  and  swampy 
■soils  in  Ceylon — Treatment  of  swampy  soils — Hevea  rubber  soils  in  various 
•  districts  of  Ceylon — Kelani,  Kegalla,  Kalutara,  Galle,  Matale,  Pussellawa, 
Ratnapura,  .Sabaragamuwa,  Ambagamuwa,  Kurunegala  and  Passara  districts 
— Soils  in  South  India — Hevea  rubber  land  and  soils  in  the  Federated  Malay 
States — Soils  in  the  Klang  district — Peat  soils — Selangor  soils — Typical  soils  of 
Malay  States — Soils  in  Java — Soils  in  Sumatra — Soils  in  British  ISfew  Guinea — 
Soils  in  Hawaii — Soils  in  the  West  Indies  and  South  America — Soils  in  British 
■Guiana — Manuring  for  increasing  the  yield  of  latex — Hawaiian  experiments — 
Forest  vegetation  and  soil  improvements — Food  in  Hevea  leaves — Apphcation 
of  readily  soluble  artificial  and  also  bulky  manures — The  method  of  manur- 
■ing  young  and  old  plants — The  rootlets  and  manuring — Artificial  and  green 
manures — Results  of  manuring  experiments — PZffects  of  nitrogen  and  potash — 
Manurial  experiments  in  Sumatra — Manurial  experirnents  in  Ceylon — Manurial 
■experiments  in  Malaya — Manurial  experiments  in  Hawaii — Soil  constituents  in 
woody  stems,  twigs  and  leave.s — Composition  of  artificial  manures — Manure 
■mixtures — Turning  weeds  into  the  soil — Green  manuring  for  Hevea  trees — 
Limit  six  to  eight  years — Disadvantages  of  green  manures — Herbaceous 
plants — Their  composition — Tree  forms — Dadaps  and  Albizzia — Green 
manuring  in  Malaya — Its  cost  as  against  clean  weedin,g — Experiments  with 
-various  green  manures  in  Malaya — Recent  experiments  in  Cevlon  and  soil 
wash.  149-178 

CHAPTER    IX. 

Tapping  Operations  and  Implements. 
Importance  of  tapping  operations — The  thickness  of  the  bark  tissues,  and 
-shedding  of  dried  latex  tubes — Effect  of  bad  tapping — ^Bad  tapping  on  old 


xii  CONTENTS. 

trees  in  Malaya — Knives  made  on  the  estate — Requisites  of  a  good  tapping 
knife — Recommendations  of  Judges  at  the  Ceylon  Rubber  Exhibition — Clean 
cuts  versus  scraping — Protection  of  the  cambium — Paring  from  left  to  right 
and  right  to  left — Minimum  excision  of  cortex  and  bark — Push  and  pull 
implements — Paring  and  pricking — Tapping  knives — The  carpenter's  chisel — 
The  farrier's  knife — Gouges — Surgical  scrapers  and  planes — Beta  knife — Gol- 
ledge's  knife-  Holloway's  knives  -Mackenzie's  knife-  Collet's  knife — Para  knife 
and  chisel — Cater-Schofield  knife — Eastern  Produce  and  Estate  Co.'s  knife — 
Bowman  and  Northway's  knives,  construction,  method  of  use — A  new  Bow- 
man-Northway  knife — Dixon's  knife,  construction,  improvement — Macadam's 
comb  pricker; — Macadam  Miller  paring  knife — Miller's  knife — Sculler's  knile — 
Barrydo  tapping  knife — Pask  Holloway  knife — The  Secure  knife — Kerckhove's 
knife — Norzagaray 's  knife — Walker's  Combination  knife — The  Scorpion  paring 
knife — Tisdall's  knife — Srinivasagam's  knife — The  Huber  knife — The 
Burgess  tapping   knife — Wynn,   Timmins  knife — Reafer  knife.  179-193 

CHAPTER    X. 

How  TO  Tap. 

Principles  to  be  followed  in  tapping — Methods  of  collectors  in  Brazil — 
Methods  in  Africa — Estate  Methods  of  tapping — Single  obUque  cuts — Basal  ^'  or 
Y — Multij)le  incisions — Limitations  of  the  V  system — Yield  from  V  Tapping  in 
Ceylon  and  Indo-China — Herring-bone  system — Zig-zag  tapping — Northway 
and  Bowman's  spiral  curves — When  spiral  tapping  can  be  used — Yield  from 
spiral  tapping  in  Ceylon — Peradeniya  trees — Henaratgoda  trees — New  tapping 
systems  in  Ceylon — A  vertical  system  for  young  trees — Comparison  of  yields 
by  different  systems  of  tapping — Spiral  and  herring-bone  tapping  compared — 
Half-herring-bone  and  basal  Y  systems — Half  herring-bone  and  V  systems 
in  Java — Estate  conditions  in  tapping — Excision  versus  incision  in  Brazil — 
Pricking  and  paring  methods — General  principles  in  systems  of  tapping — 
Direction  of  cuts — Upper  and  lower  sides  of  cuts — Supervision  of  tapping — 
Parallel  and  irregular  paring — Xumber  of  trees  tapped  per  cooly — Number 
of  tapping  cuts  per  inch — Distance  between  tapping  lines — Tables — Tapping 
systems  and  other  considerations — Arguments  of  two  managers — General  estate 
systems  of  tapping — Three-year  system — Four-year  system,  tapping  opposite 
quarters — Four  year  system,  tapping  one-quarter  each  year — Northway  and 
Bowman's  system  of  marking  the  trees — Holloway's  system  of  marking — 
The  collecting  and  storing  of  the  latex — A  protector — Centralizing  the  latex 
from  many  trees — Drip  tins  ;  their  construction  and  action — Collecting  cups 
and  spouts — Number  of  collecting  cups  required— Glass  and  earthenware  cups 
and  cleanliness.  194-217 

CHAPTER    XI. 
Where    to    Tap. 

Occurrence  of  latex  in  parts  of  the  plants — Areas  tapped  on  estates — Basal- 
tapping  of  young  trees — Experiments  in  Ceylon  and  Singapore — Best  yielding 
areas — Yields  from  base  to  6,  lo  to  20,  20  to  30,  base  to  30  and  50  feet  in  Ceylon 
— Yielding  capacity  of  bark  at  different  levels  in  Ceylon  and  Java — High 
tapping  results  in  Malay — Tapping  in  relation  to  quality — Tacky  rubber  from 
first  tappings — Occurrence  of  non-coagulable  latex  at  different  heights. 

218-223 
CHAPTER     XII. 
When    to    Tap. 

Time  factors  in  tapping — Importance  of  age  and  size — Accumulation  of 
rubber  in  young  trees — Rubber  from  young  trees — Analyses  of  Hevea  rubber 
from  trees  of  different  ages — Opinions  on  rubber  from  young  trees — Young 
rubber  from  Ceylon — Young  rubber  from  Malaya — Age  of  tapping  trees  in 
Malaya — A  manufacturer's  opinion  of  rubber  from  eight-year-old  trees — 
Age  and  size  considered — Minimum  size  for  tapping — Minimum  percentage 
of  trees  for  tapping — How  to  increase  the  tapping  area — Measurements  of  trees 
at  Henaratgoda  with  straight  and  forked  stems — The  best  season  to  tap — 
Tapping  during  period  of  rapid  bark  renewal — Tapping  during  leaf-change — 
Leaf-change  and  drought — Atmospheric  qonditions  and  the  flow  of  latex- — 
In  Java — Seasonal  tapping  in  Malaya — Experiments  at  Singapore — Seasonal 
results  at  Henaratgoda — 'What  part  of  the  day  to  tap — Yields    in   morning 


CONTENTS.  xiii 

and  evening  —  Experiments  in  Singapore  and  India  —  Compass  tapping — 
Frequency  of  tapping — Experiments  regarding  frequency  in  Ceylon — Alternate 
and  daily  tapping  in  Malay — Tapping  experiments  at  Buitenzorg — Frequency 
in  tapping  and  composition  of  latex — Wound  response — At  Henaratgoda — 
In  Straits  Settlements — In  Java — In  West  Indies — Explanation  of  wound 
response — Wound  response  in  24  hours  in  the  Straits — Resting  periods  during 
tapping — In  Malay — Fitting's  recommendations — Tapping  frequency  and 
bark  renewal  in  Malay — In  Ceylon — When  to  tap  renewed  bark.       224-242 

CHAPTER   XIII. 

How  Notable  Estates  are  being  Tapped. 

Investigation  into  methods  of  tapping  in  the  East — Practices  in  Malay — 
Managers'  methods  on  Batu  Caves,  Glenshiel,  Seafield,  Bukit  Rajah,  Chersonese, 
Jeram,  Labu,  Banteng,  Sungei  Krian,  Bujang,  Batak  Rabit,  Rubana,  Nova 
Scotia,  Gedong  Bagan  Serai,  Bukit  Lintang,  Batu  Tiga,  Klabang,  Brad- 
wall,  Klanang,  Sungei  Bahru,  Sempah,  Pendamaran,  Batu  Unjor,  Highlands 
and  Lowlands — Wide  adoption  of  basal  Y  on  young  trees  and  of  half-herring 
bone  systems — Average  distance  between  tapping  lines  and  number  of  cuts 
per  inch — Division  of  opinion  regarding  daily  or  alternate  tapping  and  best 
knife — Managers'  methods  on  Ceylon  estates — Grand  Central,  Dimbula  Valley, 
Rayigam,  Narthupana,  Geragama,  Pelmadulla,  Lochnagar,  Penrith,  Mahawale,, 
Matale  estate.  Old  Haloya,  Beddewella,  Suduganga,  Mudumana,  Ingoya, 
Mariawatte,  Atgalle,  Dunedin,  Humbuswalana,  Dewalakande,  Houpe,  AUuta, 
Lavant,  Debatgama,  Maousava,  and  Muwankande  Rubber  Estates  of  Ceylon 
— Greater  variation  in  systems  of  tapping — Preference  for  tapping  on  alternate 
days — Tendency  to  use  more  complicated  knives — Managers'  methods  in 
Sumatra — Serdang  Central,  Soengei  Gerpa.  Bangoen  Poerba,  Soengei  Roean, 
Blankahan,  Bandar  Sumatra,  and  Anglo-Sumatra — Preference  for  alternate 
day  tapping  and  half-herring  bone  system — Managers'  methods  in  Java, 
Borneo,  Samoa,  and  South  India,  on  Bantardawa,  Sekong,  Upolu,  Poonmudi, 
Vanguard,  Glenburn,  and  Hawthorne,  estates.  243-249 

CHAPTER  XIV. 

Effects  of  Tapping. 

Effect  of  repetitional  bark  stripping — Danger  of  annual  cortical  stripping 
— Effect  of  tapping  on  plant  reserves — Excision  and  Incision — Pricking  and 
paring  in  Ceylon  in  1908 — The  Northway  system — Bad  effects  of  pricking — 
Reasons  for  suspending  judgment — Effect  of  tapping  on  periodicities — Tapping 
and  change  in  foliar  periodicity — Effect  of  tapping  on  seeds — Effect  of 
tapping  on  growth — Frequency  of  tapping  and  reduction  of  yield  of  rubber — 
Frequency  of  tapping  and  lowering  of  quality  of  rubber — 'Time  required  for 
accumulation  and  concentration  of  latex — Reduction  in  percentage  of 
caoutchouc — Experiments  at  Singapore,  in  Ceylon — Haas  on  effect,  of  tapping 
on  latex  composition  in  Java — Schidrowitz  and  Kaye  on  abnormal  latex 
with  low  caoutchouc  content — Stevens  on  abnormal  latex.  250-259 

CHAPTER    XV. 

Tapping  and  Yields  in  the  Amazon  Region. 

Amazon  merhods  behind  those  of  Middle  East — When  tapping  is  done — 
The  day's. work — The  tapping  implement  and  size  of  cut — Depth  of  cut — 
Effects  of  bad  tapping — Methods  of  collecting  latex — Method  of  tapping — 
The  number  of  cuts  made — Number  of  cuts  in  Bolivia  and  Peru — Number 
of  trees  in  an  estrada — Distance  between  the  trees — The  girths  of  tapped  trees 
— The  minimum  age  for  tapping — Duration  of  the  tapping  season — Tapping 
frequency — Wound  response  on  the  Amazon — Resting  of  the  trees — Collection 
of  the  latex — The  method  of  coagulation — Considerations  affecting  Amazonian 
yields — Yields  in  Brazil — Yields  in  Peru — Yields  in  BoUvia — Average  yield 
on  the  Amazon.  260-271 

CHAPTER     XVI. 

Yields  in  Malaya. 

Records  of  yields  from  trees  2f  to  25  years  old- — Early  yields  from  trees 
9f  known  age — Yields  from  young  trees — Yields  from  old  trees — Yields  from 


xiv  CONTENTS. 

old  trees  of  doubtful  age — Yields  from  trees  3  to  25  years  old  from  Straits 
Beitam,  Bagan  Serai,  Straits  Rubber,  Batak  Rabit,  Sungei  Krian,  Jeram, 
Batu  Caves,  Carey,  Lanadron,  Linggi,  Pandan,  Castleiield,  Banteng,  F.M.S., 
Selangor,  Klanang,  Bakap,  Glenshiel,  Seafield,  Changkat  Salak,  Batu  Tiga, 
Gula  Kalumpong,  Batu  tJnjor,  Sendayan,  Lumut,  Taiping,  Jementah,  Sbel- 
ford,  Chersonese,  Kapar  Para,  Seremban,  Vallambrosa,  Tremelbye,  Sengat, 
Kinta  Kellas,  Buklt  Rajah,  Merton,  Allagar,  Consolidated  Malay,  Inch  Kenneth, 
Jugra,  Sempah,  Highlands  and  Lowlands,  Kurau,  Eow  Seugi  Rubana,  Pataling, 
Balgownie,  Rembia,  Golconda,  Labu,  North  Hummock,  Malacca,  Harpenden, 
Anglo  Malay,  Cicely,  Perak,  Golden  Hope,  Ledbury,  Sione,  Selinsing,  Singa- 
pore Para,  Parit  Buntar,  and  Gapis  estates  in  Malaya — Trees  3  to  5  years  old — 
Trees  4  to  5  years  old — 4  to  6,  7,  8,  and  9  years — Trees  5  to  6  years  old^- 
.T  to  7,  8,  g,  10,  II,  12,  and  13  years — Trees  6  to  7  years  old — 6  to  8,  9,  10,  and 
II  years — Trees  7  to  8  years  old — 7  to  9,  10,  11,  and  13  years — Trees  8  to  9 
years  old — Trees  9  to  10  years  old — Trees  10  to  11  years  old-?— Trees  11  to  12 
years  old — Yields  from  trees  12,  14,  17,  and  25  years  old — Y'ield  per  acre 
and  per  tree — Range  of  from  J  to  61  lb.  per  tree  average — Range  of  from  50 
to  758  lb.  per  acre  average — Successive  annual  yields  from  specified  trees — 
Remarkable  yields  from  the  F.M.S.  Co.,  estates — Annual  yields  from  the 
whole  of  Malaya — Trees  tapped  in  1906,  1907,  1908,  1909,  and  1911,  and 
yields  during  those  periods.  272-286 

CHAPTER   XVII. 

Yields  in  Ceylon  and  South  India. 

Comparison  of  yields  from  Ceylon  and  Malaya — First  recorded  yields  from 
Ceylon — Yields  from  young  trees — Yields  from  old  trees — Record  yield  of 
80  lb.  per  tree  per  annum — Yields  from  trees  4  to  15  years  old  from  Mahawale, 
Rubber  Plantations  of  Kalutara,  Rayigam,  Pelmadulla,  Bedewella,  Grand 
Central,  Narthupana,  Kepitigalla,  Penrith,  Suduganga,  General  Ceylon 
Rubber  and  Tea,  Deviturai,  Lochnagar,  Doranakande,  Glendon,  Passara 
group,  Taldua,  Southern  Ceylon,  Dangan,  a  Matale  estate,  and  Igalkande 
estates  in  various  parts  of  Ceylon — Trees  4  to  6  years — 5  to  7  years — 6  to  7 
years — 7  to  9  years — 9  to  11  years — 12  to  15  years — Yields  per  acre  and  per 
tree — From  31  to  469  lb.  per  acre  average — From  0'4  to  3-65  lb.  per  tree 
average — Past  yields  per  acre  from  the  whole  island — One  ton  per  to  acres 
when  trees  6i  years  old — Yields  from  Ceylon  districts — Matale,  Province 
of  Uva,  Kelani,  Kalutara,  Ambalangoda,  Rayigam — Yields  from  a  well- 
known  Kalutara  estate  per  acre  and  per  tree — Yields  from  Gikivanakande 
estate — Increase  in  yield  from  notable  companies:  Rosehaugh,  Ceylon  Tea 
Plantations,  Yatiyantota,  P.P.K.,  Lavant,  Panawatte,  Pelmadulla,  Eastern 
Produce,  Woodend,  Ceylon  Para,  Grand  Central,  and  Kintyre — Yields  in 
South  India — Travancore,  Mooply  Valley,  Rani,  Periyar  companies — Yield 
from  old  trees  in  Malabar — Y'ields  at  high  altitudes  on  Hawthorne  and  Glen- 
burn  estates.  287-296 

CHAPTER   XVIII. 

Yields  in  the  Dutch  East  Indies,  Borneo,  Africa    Etc. 

Yields  in  Sumatra  from  trees  of  known  age — 3  to  4  years — 3  to  5  years — 
4  to  6  years — 4  to  7  years — 5  to  0  years — 5  to  7  years — Yields  from  trees  of 
known  age  on  Sumatra  Para,  United  Sumatra,  Sialang,  Anglo-Sumatra, 
Serdang  Central,  United  Serdang,  Serbadjadi,  Sungei  Kari,  Deli  Moeda, 
Bandar  Sumatra,  Tapanoeli,  Glen  Bervie — Yields  from  trees  10  to  13  years 
old — Yields  from  Hevea  in  J  ava — Yields  in  British  North  Borneo  :  Sekong, 
Sapong,  British  Borneo  Para,  and  Tenom — Yields  in  the  Gold  Coast  from 
trees  7  to  10  years  old — Yields  in  Cameroon,  Togo,  and  Nigeria — Yields  in 
Congo  Free  State — Yields  in  Burmah,  Indo-China,  New  Guinea,  Queensland, 
and  Surinam  297-301 

CHAPTER  XIX. 

General  Considerations  Affecting  Yields. 

Natural  variations  in  yield — Estate  conditions  affecting  yields — A  com- 
parison of  yields  in  various  countries — Rate  of  growth  and  ultimate  yields — 
Effect  of  intercrops  and  catch-crops  on  yields — Yield  and  distance  in  planting — 
Crops  on  Vallambrosa,  Caledonia,  and  Highlands  and  Lowlands  from  fields 


CHAPTER     I. 
THE     HISTORY     OF     PARA     RUBBER. 

It  is  natural  that  Christopher  Columbus  should  be  associated 
with  our  product.  History  relates  that  on  his  second  voyage  to 
America  (1493-1496)  he  saw  the  natives  of  Haiti  playing  with 
balls  of  gum.  Further  references  in  1525  were  made  to  this 
substance  by  d'Anghiera,  and  to  trees  in  Mexico  by  Torquemada 
in  1615.  These  and  many  other  historical  facts  refer,  in  all 
probability,  to  rubbers  from  trees  other  than  Hevea. 

Priestley,  in  1772,  by  pointing  out  that  the  substance  from 
the  trees  had  the  power  of  removing  pencil  marks  from  paper, 
was  responsible  for  the  name  indiarubber  by  which  the  product  is 
likely  to  be  known  to  the  English  for  all  time. 

It  was  not  until  Charles  Goodyear  and  Thomas  Hancock 
pointed  out,  in  1842  and  1843,  the  changes  consequent  on  applying 
heat  to  raw  rubber  with  which  sulphur  was  mixed,  that  this  sub- 
stance took  its  place  as  one  of  the  most  important  commercial 
products  with  which  plants  can  be  associated. 

Probably  the  first  account  of  species  of  Hevea  was  that  made 
by  Condamine,  who,  in  1773,  was  sent  to  measure  an  arc  of  the 
meridian  near  Quito  (Kew  Bull,  1906).  The  tree  yielding  rubber 
in  the  Andean  region  was  named  Heve  or  J  eve  ;  in  the  Amazon 
valley  it  was  called  Cahuchu — a  word  which  suggests  similarity 
to  the  German  Kautschuk  [caoutchouc).  In  Brazil  the  Portuguese 
generally  call  the  rubber'  Seringa,  the  native  collectors  Serin- 
gueiros,  and  the  tree  Pao  de  Seringa.  In  the  Kew  Bulletin, 
1906,  it  is  stated  that  ' '  these  names  suggest  that  the  syringe  was 
one  of  the  earliest  uses  to  which  indiarubber  was  locally  applied." 

Various  Rubbers  from  Hevea  and  other  Species. 

The  position  now  occupied  by  species  of  Hevea  as  sources  of 
rubber  is  indicated  by  the  following  table  (Spence,  Lectures  on 
Indiarubber)  : — 

Chief 
Trade  Name.        Geographical  Origin.         Export  Botanical  Origin. 

Centres. 

I. — Para,    fine     Is-  Brazil,  the  islands  Para        Hevea   brasiliensis, 

land,   soft  cure,  of  the  lower  Ama-  Muell.  Arg. 

2. — Para  entrefine,  zon  and  its  delta,  Hevea  sy.  " Itauba," 

Islands     entre-  also  other  parts  of  Ule. 

fine.  the  State  of  Para.  Hevea  Sprueeana, 

3  — ^Negroheads    or  Muell.  Arg. 

■  Islands  coarse,  "  ~  Sapium  taburu,  Ule. 

Semamby. 


PARA     RUBBER 


Chief 
Trade  Name         Geographical  Origin.    Export 

Centres. 


Botanical  Origin. 


4. — Fine  Para,  up- 
river,  hard  cure 

5. — Upriver  entre- 
fine,  hard  en- 
trefine. 

6. — Upriver  coarse 
or  Manaos 
Scrappy 
Negroheads. 


The  district  lying     Manaos, 
on   both  sides   of     Para, 
the   Amazon   and     Iquitos, 
some  distance  up.     Serpa. 
Also    the    district 
drained      by      its 
large     tributaries, 
the  Jurua,  Madeira, 
Rio     Negro,    etc. 


Hevea    brasiliensis, 

Muell.  Arg. 
Hevea  sp.'  Itauba '  Ule 
Hevea  discolor,  Muell. 

Arg. 
Hevea   sp.  from   Rio 

Negro. 
Hevea  similis,  Hemsl. 
Hevea     biglandul- 

osum,  Ule. 
Micrandra  syphon 

aides,  Benth. 


7. — Cameta  Negro- 
heads. 


8. — Caucho  Bails. 

(Also  Peruvian) 
9. — Caucho   Slabs 

and  Strips. 

(Also  Peruvian) 


South  Western  River  Har-  Hevea  brasiliensis, 
Para.  bour,  Cameta.      Muell.  Arg. 

Hevea  Spruceana, 
Muell.  Arg. 

Sapium  tabura,  Ule. 


Amazon      district  Manaos, 

and    its    southern  Para, 

tributaries        also  Iquitos, 

yielding  Para.  Serpa. 


Hevea  brasiliensis 
and  other  Hevea 
species. 

Various  species  of 
Sapium  for  Caucho 
bianco  and  Cas- 
tilla  Vlei,  Warb., 
for    Caucho-negro. 


I  o. — Matto-Grosso, 
fine  and  entre- 
iine. 

II. — Matto  -  Grosso, 
Virgin  Sheets, 
White  Para. 

12  — Matto-Grosso, 
Negroheads. 


13. — Bolivian,      fine     Bolivia. 

medium. 
14. — Virgin,    coarse,         do. 

entrefine. 
15. — Uncut     Bol-  do. 

ivian. 


Province   of   Mat- 
to-Grosso,   Brazil. 


do. 


do. 


Montevideo. 
Rio  de  Jan- 
eiro. 


Manaos, 
Mollendo, 
Arica,    & 
various 
Peruvian  & 
La  Plata 
Ports. 


Hevea,  probably 
brasiliensis ,  and 
others. 


Various     species     of 
Hevea. 


16. — Mollendo,   fine,     South  Bolivia,  and     Mollendo.       Various     species     of 
medium       and     smalllFlotsSjifrom  Hevea. 

coarse.  Peru. 


17. — ^Peruvian,   fine,     Peru. 
medium       and 
scrappy. 
Peruvian  Balls 
(also  Caucho). 


x8. — Orinoco,  also 
Angostura  or 
Ciudad  Bolivar. 


Venexuela. 


Iquitos. 
Manaos. 
Mollendo. 


Ciudad 
Bolivar. 


Hevea      brasiliensis, 

Muell.  Arg. 
Hevea  sp.  "Ilauba, ' ' 

Ule. 


Hevea    Knuthimna^ 
Hub. 


PARA     RUBBER 


History  of  Para  Rubber  Exports. 

The  history  of  Para  rubber  exports  furnishes  one  of  the  most 
instructive  lessons  in  economic  botany.  The  most  interesting 
development  has  yet  to  be  witnessed  when  the  product  from 
plantations  established  prior  to  and  since  1906  is  placed  upon  the 
world's  market  to  compete  with  material  derived  from  the  same 
species  in  Brazil. 

Brazil  exported  only  31  tons  of  rubber  in  1827 — twenty  years 
later  624  tons  ;  in  1867  she  exported  5,826  tons  ;  and  it  was  not 
until  an  interval  of  over  fifty  years  had  elapsed  that  a  total  of 
10,000  tons  was  obtained  in  one  year  from  the  whole  of  Brazil. 
The  following  figures  (I.R.J.,  Sept.  7th,  1908)  will  serve  to  illus- 
trate the  slow  development  of  raw  rubber  supplies  from  1827 
to  1910  : — 

Exports  of  Para  Grades  (and  Caucho)  from  Brazil. 


Metric 

tons. 

340 

451 

561 

67? 

624 

901 

978. 

1,466- 

1,582 

1,632-' 


Total, 
tons. 
2,366 

2.715 
2,ig6 
1,904 
1,808 

2,673 
2,671 
2,513 
3.354 
4,034 
3.465 

5.434 
5.826 

5.651 
5.875 
6,601 
6,764 
8,217 
8,290 
7.715 
7.729 
7.908 


1827 

to  1852. 

Year. 

Metric  tons 

Year. 

(approximate). 

1827 

31 

1843 

1828 

50 

1844 

1829 

91 

1845 

1830 

156 

1846 

1836 

189 

1847 

1837 

.    283 

1848 

1838 

243 

1849 

1839 

391 

1850 

1840 

388 

1851 

1841 

339 

1852 

1842 

270 

1853  to  1 

910. 

Year. 

Amazonas 

Para. 

tons. 

tons. 

1853 

I 

2,365 

1854 

33 

2,682 

1855 

85 

2,1X1 

1856 

239 

1.665 

1857 

212 

1.596 

1858 

— 

1.745 

1859 

1x6 

2,557 

i860 

208 

2,463 

1861 

251 

2,262 

1862 

294 

3,060 

1863 

550 

3.484 

1864 

52 

3.413 

1865 

— 

3.545 

1866 

624 

4,810 

1867 

870 

4.956 

1868 

990 

4,66x 

1869 

1,096 

4.779 

1870 

J. 360 

5.241 

1871 

1.370 

5.394 

1872 

2,011 

6,206 

1873 

1,906 

6,384 

1874 

2.193 

5.522 

1875 

2,164 

5.565 

1876 

1.733 

6.175 

4  PARA  RUBBER 

Year.           Amazonas.          Para.  Total 

tons.             tons  tons. 

1877  ..    ..     2.573   ■•    •■    6.641  .•  ••     9.214 

1878  ..    ..     2,773   ••    ••    4.038  ..  •■     6,811 

1879  ..    ..     3,246   ..    ..    6,889  ■-  -•    10.135 

1880  . .    . .     3,362   . .    . .    5,317  . .  . .     8,679 

1881  ..    ..     3,385   ..    ..    5,317  ..  ..     8,702 

1882  ..    ..     4,358   ..    ..    5,713  ..  ..    10,071 

1883  .  .    . .     2,349   . .    . .    5.470  . .  . .     7.819 

1884  ••    ••     5.547   ••    ••    5.610  ..  ..    11,157 

1885  ■•    ••     5.508   ..    ..    6,273  ..  ..    II. 781 

1886  ..    ..     6.177   •■    ■■    6,512  ..  ..    12,689 

1887  •  ■    ■■     6,744   •  ■    •  ■    6,645  . .  . .    13.389 

1888  ..    ..     8,011   ..    ..    7,678  ..  ..    15.699 

1889  ••    ..     7.818   ..    ..    8,171  ..  ..    15.988 

1890  . .         10,710   . .    . .    4.644  . .  . .    15.354 

1891  . .          9.345   •  •         7.304  .  •  •  ■    16.649 

1892  ..         11.775   ■•    ••    6,474  •■  ■-    18,249 

1893  •  ■    •  •    10,809        . .    8,240  . .  . .    19.049 

1894  ••         11,661        ..    8,048  19.709 

1895  ..    ..    11,100   ..    ..    8,209  ..  ..    19.309 

1896  . .    . .    12,385   . .    . .    8,870  . .  . .    21,255 

1897  ■  •    •  ■    12,905   . .    . .    9,834  . .  - .    22,739 

1898  ..    ..    12,596   ..    ..    9.312  ..  ..    21,908 

1899  ..    ..      —     ..    ..    9,736  ..  ..      — 

1900  . .      —     . .    . .    9,954  . .  — 

1901  . .         15,694   . .        13.467  28,161 

1902  . .    .  .    13. 711   •  ■    •  •    13.406  27,117 

1903  . .    16,509        . .    12,559  .  .  . .    29,068 

1904  ..    ..    15.334   ••        13. 171 28,505 

1905  ■ .    . .    15.253   ■  •    •  ■    16,221  31.474 

1906  . .           . .    . .  .  .  . .    34.220 

1907  . .    . .           . .    . .  . .  . .    36,921 

1908  . .    . .           . .    . .  . .  36,991 

1909  ..                 ..    ..  ..  39.112 

1910  . .    . .            . .    . .  . .  38,200 

The  figures  for  1906  to  1910  are  those  given  by  the  British 
Consul  at  Para,  and  refer  to  the  exports  (including  caucho)  from 
Para,  Manaos,  etc.  Messrs.  Samuel  Figgis  and  Co.,  London,  give 
the  following  statistics  of  crop  in  their  annual  report  for  191 1  : — 

1911.  1910.  1909.     1908. 

tons.  tons.  tons.      tons. 

Brazil,  Peru,  and  Bolivia     37.730  38,200  39,050   38,160 

Including  Peruvian  and  Caucho 6,440  8,160  8,250     7.460 


African  Crops. 

It  is  interesting  to  note  the  progress  of  African  crops,  as 
compiled  by  Messrs.  Samuel  Figgis  &  Co.  The  following  figures 
are  given  : — 

1911.     1910.      1909.       1906. 
tons.       tons.       tons.       tons. 

West  Coast  African  (total  about)      15.000     14,800     15,500    17,200 

including  Benguela  and  Mossamedes 1.900       1,600       1,920      1,450 

Loanda 430         800         950        700 

Congo,  French  Congo  and  Soudan        6,200      6,000      6,300      5.900 


PARA     RUBBER  5 

A  more  complete  set  ot  statistics  (I.R.J.,  Dec.  30th,  1911), 

is  now  available,  showing  the  output  for  practically  the  whole  of 
rubber -producing  Africa  :— 

1909.  1910 

tons.  tons. 

French  Colonies      6,647  7.34° 

Congo  Free  State    5,217  5,000 

Portuguese  Possessions     3, 161  3,504 

British  Colonies 1.974  2,818 

German  Colonies    2,114  2,800 

19,113  21,462 

The  production  of  some  parts  of  Africa  not  included  in  the 
above  table  would  probably  bring  the  figures  up  to  22,000  tons 
or  thereabouts  in  19 10. 

The  foregoing  details  give  us  some  idea  of  the  progress  of 
wild  rubber  supplies  from  the  two  principal  continents — tropical 
America  and  Africa.  It  is  now  necessary  to  study  more  closely 
the  conditions  prevailing  where  these  huge  quantities  of  rubber 
have  been  harvested,  and  to  detail  the  changes  likely  to  occur  in 
consequence  of  plantations  having  been  established  in  other  parts 
of  the  world. 

Wild   Rubber   Developments. 

Hitherto  wild  rubber  has  been  obtained  from  forest  trees  or 
vines  indigenous  in  local  areas,  and  has  been  collected  mainly  by 
native  labourers  who  have  bargained  their  harvests  for  articles  of 
food,  etc.,  and  who  in  their  work  have  frequently  adopted  methods 
requiring  the  minimum  skill  and  involving  the  destruction  of  the 
plants.  To-day,  the  business  of  rubber  exploiting  in  tropical 
America  and  Africa  is  being  supervised  by  companies  which  are 
aiming  at  the  preservation  of  the  original  wild  plant,  and  in  some 
cases  the  reafforestation  of  areas  poorly  represented  in  wild  rubber 
species  by  indigenous  or  introduced  rubber-yielding  trees  of 
known  value.  The  terms  under  which  much  land  has  been  leased 
in  Brazil  and  the  Congo  provide  that  a  definite  acreage  shall  be 
planted  each  year,  thus  ensuring  that  the  sources  of  supply  shall, 
if  possible,  be  maintained. 

Importance  of  Wild  Rubber  Supplies. 

The  sources  of  wild  rubber  are  receiving  much  more  con- 
sideration and  care  than  was  the  case  a  few  years  ago,  and  may 
for  many  years  to  come  be  expected  to  annually  supply  large 
quantities  of  the  raw  material.  Rubber  manufacturers  have 
hitherto  been  dependent,  almost  entirely,  on  wild  rubber  ;  and 
it  seems  illogical  to  suggest  that  the  rubber  forests  on  which  so 
much  new  capital  and  enterprise  have  been  recently  expended, 
and  in  which  prominent  scientific  and  business  men  are  concerned, 
will  be  unable  to  satisfy,  in  part,  the  increased  demand  expected 
in  the  next  few  years. 

Though  the  extraction  of  rubber  from  indigenous  trees,  vines, 
and  shrubs  in  African  and  American  forests  has  been  hitherto 


6  PARA    RUBBER 

mainly  carried  out  at  the  sacrifice  of  the  plants  yielding  caout- 
chouc, it  must  not  be  surmised  that  this  practice  is  always  adopted. 
In  only  one  case — guayule — does  destruction  of  the  plant  appear 
necessary.  Most  of  the  companies  of  recent  birth,  formed  for 
the  exploitation  of  rubber  from  wild  sources,  are  pajdng  attention 
to  the  planting  of  ordinary  jungle  or  areas  which  already  possess  a 
fair  proportion  of  rubber  trees,  and  are  carefully  supervising 
collecting  operations  wherever  possible. 

Change  in  Wild  Rubber  Grades. 

The  material  exported  from  the  wild  rubber  areas  in  America 
will  probably  retain  much  of  its  present  character,  whereas  that 
from  tropical  Africa  may  show  considerable  changes  in  the  future 
and  tend  to  become  somewhat  similar  to  that  from  America. 
This  is  suggested  from  a  study  of  the  developments  which  are  now 
going  on  in  both  countries.  In  American  areas  attention  is  mainly 
directed  to  the  cultivation  and  exploitation  of  species  indigenous 
there,  and  though  a  few  species  of  Landolphia,  Funtumia,  and 
Ficus  from  Africa  and  the  Indo-Malayan  region  have  been  tried, 
they  do  not  appear  to  give  very  satisfactory  results.  On  the  other 
hand,  nearly  every  part  of  tropical  Africa  is  carrjdng  out  extensive 
experiments  with  Hevea  and  Manihot  species  from  America,  and 
in  consequence  of  the  success  which  has  already  been  achieved,  one, 
if  not  more,  of  the  three  American  genera  is  likely  to  be  largely 
adopted.  The  cultivation  of  climbing  plants  and  of  root  rubbers 
is  generally  more  difficult  and  expensive  than  that  of  arbores- 
cent forms,  and  it  appears  probable  that  the  produce  of  the  latter 
will  largely  increase,  and  that  of  the  former  decrease  in  quantity. 
Judging  from  results  obtained,  it  appears  to  me  that  the  cultiva- 
tion of  species  of  Hevea,  Castilloa,  Funtumia,  Manihot,  Sapium, 
and  arborescent  forms  similar  to  them,  will  predominate  in  the 
future,  and  that  of  species  of  Landolphia,  Crvptostegia,  Clitandra, 
Carpodinus,  and  Willughbeia,  etc.,  gradually  become  relatively 
insignificant.  Plants  of  the  former  group  require  less  supervision, 
they  attain  maturity  at  an  earlier  age,  they  allow  of  continuous 
tapping  operations  for  several  years  on  the  same  tree,  and  under 
certain  conditions  yield  rubber  in  larger  quantity  and  of  better 
quality  than  do  those  of  the  latter  class. 

In  the  Indo-Malayan  region,  the  indigenous  species  of 
Crvptostegia,  Leuconotis,  Parameria,  Rhynchodia,  etc.,  and  even  of 
Ficus  and  Sapium,  are  gradually  being  neglected  in  preference  to 
those  from  tropical  America.  Species  of  Manihot,  Ficus,  and 
Castilloa  do  not  appear  to  give  as  favourable  results  as  Hevea 
hrasiliensis,  and  before  very  long  that  area  will  stand  out  re- 
markably for  the  uniformity  of  the  greater  part  of  its  exported 
rubber.  Hevea  hrasiliensis  appears  to  have  been  taken  up  in  the 
East  almost  to  the  exclusion  of  all  other  rubber-jdelding  plants, 
and  even  the  coconut  palm  has  been  felled  in  order  to  make  room 
for  this  favourite  species.  It  is  very  rare  in  Ceylon  or  Malaya 
that  one  meets  with  plantations  of  Castilloa,  such  as  those  in 
Mexico,  or  of  Manihot,  as  in  parts  of  Bahia  and  East  Africa. 


PARA     RUBBER  7 

Differences  between  Wild  and  Plantation  Areas. 

Eastern  rubber  estates  are  nearly  all  planted  with  tree  forms  ; 
only  a  few  possess  indigenous  trees  or  climbers,  and  the  waiting 
period  is  consequently  very  long.  Properties  in  Malaya,  possessing 
trees  of  the  indigenous  Ficus  elastica,  have  nearly  all  been 
regularly  and  systematically  planted  with  seedlings  reared  in  the 
nursery,  and  in  this  feature  differ  from  the  wild  or  pseudo-wild 
areas. 

Again,  it  may  be  stated,  with  some  degree  of  acciaracy,  that 
the  rubber  output  from  most  parts  of  tropical  America  and 
Africa  is  .dependent  upon  native  efforts  ;  there  the  amount  of 
skilled  supervision  is  small  compared  with  that  on  planted  estates 
in  the  East.  I  have  been  informed  by  residents  in  prominent 
wild-rubber  areas  that  they  have  only  a  few  practical  men  of 
repute.  In  Ceylon,  Southern  India,  Sumatra,  Java,  Borneo, 
Federated  Malay  States,  Straits  Settlements,  etc.,  the  estates  are 
managed  by  Europeans  having  considerable  tropical  experience, 
and  their  system  of  keeping  records  and  accounts,  and  their 
knowledge  of  engineering,  survejdng,  languages,  etc. — all  of 
which  play  a  very  important  part  in  the  ultimate  success  of  any 
rubber  plantation — are  such  as  to  command  complete  confidence. 
The  number  of  planters  drawn  from  Ceylon  to  engage  in  the 
rubber  industries  of  the  Malay  Archipelago  is  very  large,  and  from 
a  few  years'  experience  in  that  island  I  anticipate  that  good 
work  will  be  done. 

It  is  now  generally  admitted  that  Hevea  brasiliensis  has,  on 
Eastern  plantations,  been  proved  to  give  excellent  results,  and  to 
stand  tapping  operations  even  of  a  very  drastic  nature.  This  can- 
not yet  be  asserted  for  many  Castilloa  plantations  in  Mexico  and 
Central  America,  or  even  for  those  of  Manihot  (Ceara)  in  Brazil, 
or  Landolphia  and  Funtumia  in  Africa,  though  favourable  results 
from  many  of  these  are  expected. 

Plantations  of  rubber  trees  are  capable  of  being  worked  more 
economically  than  forests  of  mixed  plants  ;  the  number  of  rubber 
trees  is  generally  accurately  recorded,  they  are  capable  of  being 
minutely  inspected  daily,  and  there  are  often  more  rubber  trees 
in  one  acre  of  an  Eastern  plantation  than  in  several  square  miles 
of  American  and  African  forest.  Of  course,  it  is  possible  to  plant 
in  any  country,  but  the  abundance  and  cheapness  of  the  Indian, 
Javanese,  Chinese,  and  Malay  labour  make  it  possible  to  do 
planting  work  cheaper  in  the  East  than  in  most  parts  of  the  tropics. 

It  is  asserted  by  many  that  tropical  plants  vnll  thrive  best 
in  their  native  habitats  ;  this  statement  can  be  seriously  con- 
tested, and  is  often  contradicted  by  the  results  obtained  from 
introduced  plants  in  the  tropics.  True,  the  indigenous  rubber- 
producing  plants  in  the  American  and  African  forests  represent 
types  which,  in  their  native  countries,  have  survived  in  the 
struggle  for  existence,  and  have  often  successfully  contested 
certain  pests.     But  it  is  well  known  that  a  change  of  climate  is 


8  PARA    RUBBER 

sometimes  beneficial  to  the  plants,  and  that  under  cultivation  they 
may  jdeld  far  larger  crops  than  in  their  wild  native  state. 

Future  Supplies  from  Brazil. 

The  foregoing  remarks  must  not  be  taken  to  suggest  that  the 
sources  of  wild  rubber  are  going  to  be  completely  obliterated 
when  supplies  from  plantations  are  forthcoming  in  large  quantities. 
I  believe  that  plantations  will  more  severely  affect  the  inferior 
wild  rubbers  from  Africa  than  the  first-quality  grades  from  Brazil. 
Furthermore,  the  effect  on  the  latter  will  only  be  one  of  curtailment 
and  not  entire  obliteration.  It  has  been  the  same  in  the  history  of 
many  other  tropical  products.  It  should  never  be  forgotten 
that  Brazil  lives  on  its  rubber  and  is  not  likely  to  allow  such  a 
source  of  revenue  to  be  entirely  destroyed ;  a  large  number  of 
the  natives  have  no  other  means  of  making  a  living  other  than  by 
collecting  rubber.  Witt  (Lectures  on  Indiarubber)  assures  us 
that  "it  is  not  at  all  unhkely  that  even  at  low  prices  people  in 

Brazil  will  be  able  to  compete  very  well  with  the  East      

Should  rubber  prices  ever  go  very  low  it  is  not  to  be  supposed  that 
the  Governments  ....  would  keep  up  the  heavy  taxation  of 
rubber  ....  There  is  a  very  big  margin  left  should  prices 
ever  drop,  say  to  2s.  per  lb."  Other  tropical  industries  could 
be  mentioned  which  are  kept  alive,  by  native  labour,  when 
Europeans  find  it  unprofitable  to  engage  in  them. 

Vasconcellos,  the  Commissioner  for  the  Federal  Government 
of  Brazil,  reminded  us  quite  recently,  that  Brazil  was  the  habitat 
of  rubber  and  that  the  Government  were  quite  aware  of  the 
competition  ahead.  Speaking  of  Brazil  he  said,  "It  is  awake 
also  to  the  necessity  for  arming  itself  with  instruments  equal  to 
those  of  its  competitors,  so  that  it  may  obtain  its  due  ;  not 
privileges,  but  fairness  and  justice.  It  is  only  right  that  you  should 
know  that  my  Government  is  pajnng  great  attention  to  the 
necessity  of  ameliorating  the  rubber  situation  in  the  country  by 
removing  the  two  obstacles  which  exist  at  present,  want  of  labour 
organisation  and  excessive  taxation. "  It  is  quite  clear  that 
Brazil  is  fully  alive  to  the  necessity  of  protecting  its  main  source 
of  revenue. 

Sandmann  is  of  the  opinion  that  the  living  expenses  of  the 
seringueiro,  now  the  equivalent  of  is.  lod.  per  day,  are  xery  high 
on  account  of  the  absurd  prices  of  food  ^uffs.  These  can  be 
reduced  by  more  efficient  organization,  and  by  opening  up  the 
land  for  the  cultivation  of  food  crops,  In  this  way  there  appears 
to  be  a  possibility  of  reducing  the  average  daily  cost  to  about  6d., 
which,  if  accompanied  by  the  abolition  of  taxes,  would  enable 
supplies  of  rubber  to  be  shipped  from  Brazil  for  some  time  to 
come. 

Government  encouraging  Plantations  in  Brazil. 
The  respective  Governments  in  Brazil  have  recognised  the 
change  which  is  likely  to  take  place  in  the  raw  rubber  industry  in 
consequence    of   the   development    of   plantations    in    the    East. 


PARA     RUBBER  9 

The  Governor  of  the  State  of  Para,  in  his  annual  message  (I.R.J., 
November  14th,  1910),  warned  the  producing  interests  of  the 
State  against  the  error  of  supposing  that  South  America  was  the 
only  rubber-producing  country  of  importance.  He  drew  atten- 
tion to  the  growing  importance  of  rubber  planting  in  the  British 
Colonies.  History  had  shown  that  careful  and  scientific  culture 
competed  on  favourable  terms  with  wild  extractive  industries. 
It  was  not  that  he  did  not  have  confidence  in  the  industrial  and 
commercial  future  of  Para.  But  he  warned  them  against  pro- 
digality during  periods  of  abundance,  and  urged  the  necessity 
of  forming  plantations.  He  did  not  despair  of  Para  holding  it& 
own  if  these  recommendations  were  adopted,  and  provided  that 
production  was  at  least  doubled. 

Two  years  ago  I  pointed  out  {I.R.J.,  December  13th,  1909,) 
that  the  Brazilian  Federal  Government  was  about  to  make  a 
move  in  the  systematic  planting  of  rubber.  It  was  proposed 
to  offer  those  who  would  undertake  to  plant  a  million  trees  or  so, 
free  land  and  total  exemption  from  duties  on  exports  of  rubber 
for  a  long  term  of  years,  with  possible  participation  by  Govern- 
ment in  profits. 

According  to  the  Consular  Report  for  1909  it  is  owing  to  the 
defective  methods  of  tapping  and  coagulating  in  Brazil  that  only 
45  per  cent,  of  the  rubber  collected  is  "Fine,"  the  rest  being  of  the 
inferior  grades  fetching  often  only  half  the  price  of  "  Fine  "  rubber. 
During  1909  a  process  was  invented  by  Dr.  Pinto  for  preparing 
crude  rubber,  and  to  test  the  value  of  this  preparation,  a  ton  of 
Hevea  and  a  ton  of  Caucho  prepared  by  this  system  were  to  be 
sold  on  the  open  market  in  New  York.  Dr.  Pinto  received  a. 
premium  of  £2,500  from  the  Federal  Government  for  his  invention. 

Supervision  and  Protection  of  Trees  in  Brazil. 

While  it  is  admitted  that  the  Brazilian  Government  has  recom- 
mended measures  to  stimulate  plantation  work,  but  little  appears 
to  have  been  done  in  the  way  of  protecting  the  forests  from  which 
the  States  of  Para  and  Amazonas  draw  some  70  per  cent,  of  their 
revenues.  The  difficulty  of  supervising  rubber  trees  in  the  forest 
areas  is  general  throughout  Brazil,  though  the  plantations  do  not 
suffer  in  the  same  way. 

The  Brazilian  Position  in  1910. 

At  the  end  of  1910  I  was  able  to  report  that  the  schemes  for 
fostering  Hevea  rubber  cultivation  in  Acre,  and  proposals  having 
reference  to  the  State  of  Para  and  the  Municipality  of  Anajas,  had 
progressed  satisfactorily.  The  State  of  Para  has  modified  the 
taxes  on  rubber  from  plantations,  charges  on  rubber  going  outwards 
have  been  lowered,  and  free  transport  has  been  conceded  on 
machinery,  seeds,  etc.  Furthermore,  the  authorities  have  come 
to  the  financial  assistance  of  people  prepared  to  carry  out  planta- 
tion work  on  a  large  scale.  Companies  thus  deriving  financial 
assistance  from  Government  have  to  undertake  to  plant  several 


10  PARA     RUBBER 

thousand  seeds  annually,  and  to  observe  the  instructions  of  the 
Agricultural  Department ;  they  have  also  to  maintain  schools 
and  to  train  men  for  agricultural  work  on  estates.  In  the  event 
of  the  regulations  of  the  Government  not  being  compHed  with,  the 
concessions  leased  to  private  individuals  revert  to  the  State.  The 
Municipality  of  Anajas  offered  substantial ,  bonuses  for  every  500 
trees  properly  planted.  In  this  way  the  Government  are  practically 
determining  the  future  of  the  industry.  The  Peruvian  Government 
has  not  lost  sight  of  the  importance  of  plantations,  and  has  agreed 
to  pay,  in  cash,  a  premium  for  every  rubber  tree  of  three  years  old 
grown  on  a  plantation  ;  this  is  equivalent  to  giving  a  government 
guarantee  on  capital  thus  invested. 

In  1910,  Dr.  Huber,  of  Para,  wrote  that  the  premium  had 
already  been  paid  upon  over  4J  million  trees  in  Para. 

Proposals  from  Acre. 

In  August,  1909,  a  congress  of  proprietors  of  rubber  estates 
was  held  in  the  Acre  territory  to  discuss  the  best  means  of  main- 
taining prices  and  developing  the  rubber  industry.  The  message 
which  the  Congress,  on  the  conclusion  of  the  sittings,  forwarded 
to  the  President  of  the  Republic,  states  the  chief  difficulties  under 
which  the  rubber  industry  labours  not  only  in  the  Acre,  but 
throughout  the  Republic.  The  remedies  they  proposed  included  : 
Legislation  to  confirm  actual  proprietors  of  estates  in  their  posses- 
sion ;  establishment  of  roads  ;  development  of  railway  ;  subven- 
tions to  steamships  ;  further  Government  aids  to  colonisation  ; 
the  appointment  of  a  commission  to  study  rubber  plantations  in 
Ceylon,  etc.,  and  reduction  of  taxation,  especially  of  export  taxes. 
Action  upon  these  lines  would  certainly  improve  the  prospects 
of  wild  rubber  from  this  area. 

When  such  developments  by  the  various  governments  are 
considered  in  conjunction  with  the  many  improvements  in  the 
way  of  machinery  for  turning  out  better -grade  rubber,  it  is  quite 
apparent  that  though  in  the  future  the  supplies  from  these  countries 
may  be  curtailed,  we  shall  always  be  able  to  rely  upon  consider- 
able quantities  being  annually  harvested.  We  have,  however, 
some  doubts  as  to  whether  the  various  Governments  in  Brazil, 
acting  through  their  Agricultural  Departments,  will  be  able  to 
control  the  proper  planting  and  cultivation  of  subsidised  estates. 
Experience  in  the  Congo,  where  perhaps  conditions  have  not  been 
so  favourable,  does  not  inspire  us  with  confidence  in  this  work. 
Nevertheless,  we  firmly  beheve  that  some  progress  will  be  reported 
within  a  few  years  as  the  result  of  the  wise  measures  adopted  by 
Government  Departments  in  Brazil. 

Recommendations   by  the  Manaos   Rubber  Congress. 

The  Congresso  Commercial  Industrial  e  Agricola,  organised  by 

the  Commercial  Association  of  Amazonas,  with  the  support  of  the 

State  Government,  was  recently  held  at  Manaos,  and  decided  to 

recommend  to  the  pubhc  authorities  of    the  countries  and  states 


PARA     RUBBER  ii 

represented  in  the  Congress  the  re-modelling  of  the  existing  rates 
for  freightage,  especially  those  relating  to  food  supplies  requisite 
for  the  maintenance  of  workers  in  the  rubber-extracting  industry. 
They  emphasised  the  urgency  of  ameliorating  labour  conditions  in 
the  rubber-extracting  industry.  They  recommended  the  public 
authorities  of  the  State  to  improve  the  means  of  communication 
for  the  municipalities  of  Barcellos  and  Sao  Gabriel,  on  the  river 
Negro  where  the  defective  navigation  is  the  cause  of  a  great  part 
-of  the  extractive  wealth  being  as  yet  unexplored. 

The  Congress  recognised  as  a  pressing  and  urgent  necessity 
ihe  planting  of  rubber  trees  in  Amazonas  Valley,  and  made  sugges- 
iiions  regarding  model  plantations  of  Hevea  rubber  to  be  made  by 
the  States,  Municipalities,  and  Agricultural  and  Commercial 
Associations  on  their  own  account  ;  they  suggested  free  grants  of 
land  for  this  culture  ;  reduction  of  export  tariffs  for  plantation 
rubber ;  propaganda  through  the  press,  and  by  means  of 
-circulars,  etc.  demonstrating  the  advantages  of  planting  and 
giving  practical  advice  on  the  method  of  planting  ;  and  liberal  dis- 
tribution of  seeds  and  plants  of  Hevea  brasiliensis.  The  Congress 
also  recommended  the  present  owners  of  rubber  estates  to  inter- 
plant  and  re-plant  existing  estradas,  and  to  plant  in  open  spaces, 
forests,  or  any  clearing  made  in  the  forest. 

The  Congress  advised  the  Governments  to  advertise  exten- 
sively, in  Europe  and  in  the  United  States,  the  advantages  of 
investing  capital  in  the  rubber  industry  of  the  Amazonas.  Pecu- 
liar to  relate,  at  this  late  hour,  they  advised  the  planting  of 
Hevea  brasiliensis  in  preference  to  all  other  varieties,  owmg  to  the 
backward  state  of  knowledge  relating  to  the  cultivation  of  other 
■trees.  The  authorities  were  also  asked  to  exempt  from  import 
duties  all  and  every  modern  machine  intended  to  improve  the 
present  methods  of  tapping  and  preparation  of  rubber  and  kindred 
.products  in  the  Amazonas  Valley.  If  half  of  these  valuable 
suggestions  are  adopted  the  future  of  Brazilian  supplies  is  definitely 
assured. 

Sufficierit  has  been  written  to  prove  that  plantation  work 
and  protection  of  wild  trees  will  go  hand  in  hand  if  the  Brazilian 
-Government  receive  encouragement.  It  is  now  necessary  to 
turn  to  the  second  largest  source  of  raw  rubber — the  i\frican 
continent — and  see  what  steps  are  being  taken  there  to  maintain 
■a  supply. 

African    Plantations. 

It  becomes  more  evident  day  by  day  that  the  future  of  the 
Belgian  Congo  will  depend  on  the  plantations  already  established 
and  to  be  established.  It  is  averred  that  equatorial  forests, 
in  the  Congo,  in  general  are  becoming  more  and  more  exhausted, 
•which  renders  their  progressive  exploitation  more  difficult.  The 
Secretary  for  Foreign  Affairs,  London,  recently  reported  that  the 
Belgian  Government  intended  to  plant  2,000  hectares  with  rubber 
-annually. 


12  PARA     RUBBER 

The  experimental  cultivation  by  the  Government  of  Hevea 
brasiliensis,  Funtumia  dastica,  and  Manihot  Glaziovii  is  receiving 
notice,  and  extensive  areas  in  addition  to  those  already  existing 
are  to  be  cultivated.  About  2,470  acres  have  been  planted  up  with 
Hevea  at  the  ten  centres,  and  encouraging  results  obtained.  Ex- 
periments with  Manihot  Glaziovii  have  been  made  at  20  stations, 
the  number  of  trees  being  about  185,200,  and  the  results  being 
satisfactory,  this  species  is  also  being  taken  up.  The  most  exten- 
sive plantations  are  those  of  Funtumia  elastica,  the  number  of 
trees  being  3,461,000  ;  but  it  does  not  appear  that  any  further 
development  of  this  species  is  thought  of.  Experiments  are  also 
in  progress  with  Castilloa,  various  species  of  Manihot  and  Ficus 
and  a  Euphorbia.  Attention  is  also  being  given  to  the  lianes, 
of  which  some  11,000,000  are  known  to  exist  in  plantations.  It  is 
reported  that  at  least  20,000,000  have  been  planted.  The  climatic 
and  soil  conditions  within  the  Congo  vary  greatly,  and  some  parts 
are  more  suitable  for  Manihot  Glaziovii  than  for  Hevea  brasiliensis. 

In  addition  to  Belgian  there  are  other  interests  at  work  in 
Africa — East,  West,  and  Central — which  will  enable  the  merchants 
to  maintain  a  fair  supply  of  raw  rubber  in  future  years.  Uganda, 
West  Africa  and  German  East  Africa  are  already  sending  increased 
supplies  from  semi-cultivated  trees  or  mature  plantations  of 
Funtumia  and  Manihot. 

Equivalent  Acreage  of  Wild  Rubber  Crop. 

Granting  the  existence  of  these  sources,  it  is  now  necessary  to 
determine  their  value  compared  with  regular  Eastern  plantations. 
The  annual  rubber-yielding  capacity  of  tropical  America 
can  be  assessed  at  approximately  40,000  tons  ;  this  indicates  the 
enormous  tracts  of  land  covered  by  the  wild  Hevea  trees  in  Brazil 
whence  the  major  portion  of  this  crop  is  derived,  especially  if 
Wickham's  estimate  (T.A.,  May,  1908)  of  6  or  7  trees  per  acre  is 
accepted.  Cultivated  rubber  estates  of  any  magnitude,  in  bearing, 
are  almost  non-existent  in  Brazil ;  the  produce  is  collected  from 
wild  trees  by  labourers  who  either  live  on  the  spot,  or  periodically 
visit  the  forests  as  soon  as  the  rivers  have  subsided.  To  determine 
the  equivalent  of  these  wild  trees  in  terms  of  planted  acreage  is 
extremely  difficult  owing  to  the  varying  age  and  yielding  capacity 
of  the  trees.  If  we  assume  that  the  wild  trees  yield  at  the  rate  of 
4  cwt.  (say,  450  lb.)  per  acre  per  annum,  the  annual  crop  of  rubber 
from  Brazil  is  equivalent  to  that  obtainable  from  only  200,000 
planted  acres,  assimiing  the  crop  to  be  pure  rubber. 

Calculated  on  the  same  basis,  a  total  annual  crop  of  70,000 
tons  of  rubber  for  America  and  Africa  is  only  equivalent  to  the 
produce  from  350,000  acres.  It  is  apparent  in  this  suggestion 
that  I  have  assessed  the  yielding  capacity  of  an  acre  of  land 
planted  with  Hevea  relatively  high.  My  reason  for  doing  this  is 
that  though  my  previous  basis  of  ' '  one  ton  per  ten  acres ' '  has 
proved  to  approximate  to  the  actual  outturn  up  to  the  present 
from  Ceylon,  it  is  a  yield  which  should  be  largely  exceeded  where. 


PARA     RUBBER  13 

-well-cultivated  Hevea  trees  attain  their  seventh  year.  In  the 
-chapter  on  "Yields"  it  will  be  shown  that  a  few  estates  in  the 
East  possessing  old  Hevea  trees  have  given  crops  quite  equal  to 
4  cwt.  per  acre,  or  one  ton  per  five  acres.  The  above  deduction 
will  be  referred  to  later  when  dealing  with  a  comparison  of  future 
•crops  from  various  areas. 

Evolution  of  Eastern  Planted  Acreages. 

Having  seen  the  gradual  evolution  of  the  Brazilian  crop  from 
1827  to  1911  and  the  equivalent  in  planted  acreage  of  its  maximum 
annual  outturn,  we  are  in  a  position  to  make  a  more  interesting 
comparison  with  the  plantation  industry.  The  differences 
between  the  histories  in  the  two  areas  are  marked,  for  in  the  East 
there  is  only  a  small  crop  of  rubber  to  chronicle  up  to  1911,  though 
an  unparalleled  development  in  planted  acreages  is  recorded.  At 
some  future  date  about  200,000  acres  in  Ceylon  will  be  rubber- 
producing.  Malaya  has  about  400,000  acres  that  will  all  be  in 
bearing.  And. the  total  world's  acreage  that  may  be  depended 
upon  to  yield  is  900,000  acres.  From  the  progress  thus  made  it 
is  clear  that  the  plantation  industry  is  destined  to  play  a  leading 
part  in  the  future  of  the  world's  supplies  of  raw  rubber.  Ceylon 
!lias  now  established  a  position  which  should  enable  it  to  produce 
more  rubber  yearly  than  is  annually  turned  out  from  the  whole  of 
Africa  ;  Malaya  has  placed  itself  in  the  first  position  in  the  British 
Empire  and  should  be  able,  together  with  other  Eastern  countries, 
to  annually  produce  crops  of  rubber  greater  than  those  hitherto 
obtained  from  America  and  Africa  combined. 

-Growth  of  Brazilian  and   Plantation  Supplies   compared. 

Now  let  us  study  the  figures  showing  what  has  been  exported 
from  Brazil  from  1827  to  1911.  It  took  about  80  years  to  raise 
the  Brazilian  output  from  50  to  36,000  tons.  In  the  first  thirty 
years— 1827  to  1857 — Brazil  raised  its  output  to  1,800  tons  ; 
the  East  equalled  that  total  nearly  three  years  ago.  Brazil 
required  over  50  years  to  produce  an  annual  crop  of  10,000  tons  : 
the  East  turned  out  over  that  amount  in  1911.  But  think  of  the 
handicap — Brazil  started  with  its  dense  forest  and  old  indigenous 
tappable  trees  over  thousands  of  square  miles  of  territory.  The 
East  commenced  with  a  couple  of  thousand  seeds  secured  by 
Wickham  in  1876,  had  to  rear  them  into  seed  bearers,  and  to 
wait  for  scientific  experiments  to  demonstrate  the  value  of,  and 
public  interest  to  be  aroused  in,  the  cultivation  of  Hevea.  So  far 
the  crops  from  the  East  have  been  small,  but  when  considered  in 
relation  to  the  acreages  in  bearing,  they  unmistakably  show  that 
a  high  average  annual  yield  can  reasonably  be  expected  in  the 
future.  The  progress  of  crops  from  the  East  so  far — 500,  1,000, 
1,800,  3,800,  8,200,  and  14,150  tons — for  the  respective  years 
1906,  1907,  1908,  1909,  1910,  and  1911,  is  almost  meteoric  com- 
pared with  the  early  growth  of  wild  rubber  supplies. 


14  PARA     RUBBER 

Malayan   Exports. 

The  two  principal  sources  of  supply  will  be  Malaya  and 
Ceylon.     First  consider  Malaya. 

There  is  apt  to  be  confusion  if  one  deals  with  the  crops  of 
Hevea  rubber  from  the  F.M.S.  instead  of  the  whole  of  Malaya. 
For  instance,  the  crop  of  rubber  for  F.M.S.  in  1907  was  given  by 
the  Director  of  Agriculture  at  1,990,754  lb.,  or  893  tons  ;  but  the 
total  crop  from  Malaya  was  (F.M.S.,  Straits  Settlements,  etc.) 
2,278,870  lb.,  or  approximately  1,036  tons. 

The  Director  of  Agriculture  for  the  F.M.S.  gives  in  his  last 
report  the  total  crops  foi  Malaya  during  the  years  1906  to  1910, 
which  were  :  1906,  935,056  lb.  (425  tons)  ;  1907,  2,278,870  lb. 
(1,036  tons)  ;  1908,  3.539.922  lb.  (1,655  tons)  ;  1909,  6,741,509  lb. 
(3,064  tons)  ;    and  1910,  14,368,863  lb.  (6,531  tons). 

So  far  as  can  be  estimated  from  the  official  returns  of  exports, 
the  output  in  1911  was  nearly  double  what  it  was  in  1910. 

The  above  statistics  are  based  upon  census  papers  filled  in  by 
estate  managers.  They  are  not  the  same  as  those  given  in  the 
Annual  Return  of  Imports  and  Exports  for  the  Straits  Settlements, 
through  which  all  Malayan  rubber  at  one  time  passed. 

Distribution  of  Malayan  Rubber. 

The  following  table,  compiled  from  the  ofiicial  return  of 
exports,  shows  the  destinations  of  the  cultivated  rubber  exported 
during  the  years  1906-9  from  Straits  Settlement  ports,  but  not 
Port  Swettenham.  It  includes  rubber  produced  not  only  in  the 
peninsula,  but  also  in  the  Dutch  East  Indies  : — 


United  Kingdom     

Australia     

Hongkong   

Ceylon      

Austria     

Belgium   

Denmark     

France     

Germany     

Holland    

Italy     

United  States  of  America  . . 
Japan  


1906. 

1907. 

1908 

1909. 

cwts. 

cwts. 

cwts. 

cwts. 

6,734 

14.514 

26,830 

3,4468 

88 

284 

191 

5 
2,772 

824 

710 

2,064 
6 

1.872 

532 

i,i68 

2,492 

2,001 

100 

165 

135 

206 

55 

102 

83 

46 

20 

202 

57 

141 

14 

10 

7 

— 

122 

37 

4 

201 

32 

104 

lOI 

443 

8,407       18,658     32,677      40,202 


It  will  be  noticed  that  very  little  rubber  went  direct  from 
these  ports  to  America  during  1909.  If,  however,  the  distribution 
of  Ceylon  rubber  is  studied  for  the  same  year  it  will  be  seen  that 
large  quantities,  considerably  in  excess  of  Malayan  imports  into 
Ceylon,  were  shipped  to  America. 

Estimated    Output    from    Malaya. 

In  a  speech  made  at  Kuala  Lumpur,  Sir  John  Anderson — 
the  Governor — is  reported  to  have  stated  that,  ' '  We  have  in  the 


PARA     RUBBER  15 

peninsula  already  alienated  for  rubber  an  amount  of  acres  which 
runs  into  seven  figures.  A  great  deal  of  it  is  not  yet  under  cultiva- 
tion, although  the  capital  necessary  to  bring  it  into  cultivation  is 
available.  Actually  under  cultivation  at  present  in  the  peninsula 
there  are  400,000  acres  under  rubber,  some  of  which  is  several 
years  old  and  already  producing  large  returns.  Six  years  ago  the 
export  of  rubber  was  five  tons  ;  before  the  end  of  this  year  (19 10) 
we  shall  have  exported  at  least  6,000  tons — a  considerable  advance 
for  six  years,  but  nothing  to  the  advance  which  will  be  shown  in 
the  next  five  or  six  years. 

If  you  consider  that  there  are  400,000  acres  under  cultivation, 
a  great  deal  being  three  years  old  and  much  more,  you  may  reckon 
an  average  output  per  acre  of  400  lb.  as  not  excessive,  and  we 
shall  be  turning  out  160,000,000  lb.,  or  70,000  tons,  of  rubber  in 
six  years'  time. ' ' 

How  the  planted  acreage  of  400,000  acres  is  arrived  at  is  not 
stated,  but  the  Director  of  Agriculture  reported  that  in  1909  there 
were  292,035  acres  planted  in  the  whole  of  th3  Malay  Penin- 
sula. H.  K.  Rutherford  {I.R.J.,  October  3rd,  1910)  gives  the 
following  estimate  of  rubber  from  the  Federated  Malay  States 
only  : — 

Estimated   Output   of   Plantation   Rubber   from 
THE    F.M.S. 
Years.  Tons. 

191 1 


1912 

1913 
1914 

1915 
1916 


8,100 
12,100 
17,040 
22,670 
27,300 
35.690 


The  Director  of  Agriculture,  F.M.S.,  Mr.  Lewton-Brain,  in 
his  report  for  1910,  advances  some  estimates  of  future  yields  in 
Malaya.  The  yield  for  1910  being  6,410  tons,  he  believed  that 
10,950  tons  would  be  got  in  1911,  18,750  tons  in  1912,  26,550  tons 
in  1913,  35,640  tons  in  1914,  and  in  1916  he  estimates  65,000  tons. 

Exports  from  Ceylon. 

For  some  years  previous  to  1903,  plantation  rubber  left 
Ceylon  only  in  small  quantity,  but  in  that  year  the  exports  began 
really  to  assume  definite  proportions.  The  figures  given  by  the 
Colombo  Chamber  of  Commerce  show  how  decided  has  been  the 
increase  since  then.  All  rubb.er  passing  through  the  port  from 
Malaya,  etc.,  has  been  excluded  : — 

Tons.  Tons. 

1903 19  1908 407 

1904 34  1909 666 

1905 75  1910 1,472 

1906 147  1911  (to  Dec.  18)  2,729 

1907 248 


i6  PARA    RUBBER 

Distribution  of  Ceylon  Rubber. 

The  rubber  shipped  from  Ceylon  in  1908,  1909,  and  1910,  was 
distributed  as  follows  : — 


United  Kingdom     5,001 

Australia 

Canada     

Belgium   

France      

Germany      

Italy     

U.S.A 

China  and  Japan     

Miscellaneous      

8,143       13.326        29,452       36,287 
The  shipments  from  Ceylon  for  the  first  nine  months  of  1908, 
1909,  and  1910^  were  4,883,  7,883,  and  18,249  cwts.  respectively. 

Estimate  of  Rubber  Crops  from  Ceylon. 

A  Ceylon  correspondent  estimates  that  at  present  there  are 
220,000  acres  in  Ceylon,  from  which  in  1920  he  predicts  a  yield  of 
20,000  tons. 

In  their  directory,  Messrs.  Ferguson,  of  Colombo,  give  the 
following  as  the  probable  exports  : — 


1908. 

1909. 

1910. 

1911. 

(9  months.) 

cwts. 

cwts. 

cwts. 

cwts. 

5,001 

8,193 

14,037 

19,465 

349 

93 

52 

246 

— 

— 

67 

123 

50 

321 

686 

4,100 

24 

15 

10 

I 

437 

190 

151 

234 

10 

10 

17 

32 

2,262 

4.483 

14,379 

11,687 

— 

19 

44 

355 

10 

2 

9 

44 

Possible 

Exports. 

;s  in  bearing 

tons. 

25,000 

2,500 

40,000 

3,500 

100,000 

7,500 

150,000 

10,000 

1911   

1912  

1913  

1914  

This  is  less  than  one  ton  per  ten  acres,  and  should  be  exceeded. 

The  Outturn  of  Rubber  by  the  Larger  Companies. 

The  yielding  capacity  from  good  Eastern  plantations  will 
give  a  few  surprises  in  years  to  come.  How  many,  even  among 
the  optimists,  will  question  the  suggestion  that  some  companies 
will  individually  produce  1,000  tons  or  more  per  annum  ?  Let 
us  take  a  few  companies,  the  names  of  which  are  known  to  most  of 
us,  and  add  to  them  the  acreages  planted  or  in  course  of  planting 
ihis  year  (1911)  : — 

Present  planted 
acreage. 

Malacca  Rubber  Plantations 15,000 

Grand  Central  (Ceylon)  Rubber  Estates    12,491 

Mount  Austin  ( Johore)  Rubber  Estates     10,936 

United  Serdang  (Sumatra)  Rubber  Plantations   . .  8,285 

Anglo- Java  Rubber  and  Produce  Co 6,658 

Rosehaugh  Tea  and  Rubber  Co 6,534 

Rubber  Cultuur  Maatschappij  "  Amsterdam "     ..  6,500 

Buldt  Sembawang  Rubber  Co 6,427 

Merlimau  Rubber  Estates 5,629 

Malayalam  Rubber  and  Produce  Co 5.524 

Linggi  Plantations   5,000 

General  Ceylon  Rubber  and  Tea  Estates 5,000 


PARA     RUBBER  17 

These  acreages  include  immature  as  well  as  mature  rubber, 
and  interplanted  rubber  also  ;  but  when  all  the  Hevea  trees  on 
each  of  these  estates  have  passed  their  seventh  year,  every  one 
of  the  estates,  if  they  are  efficiently  handled,  will  eventually, 
at  the  rate  of  i  ton  per  5  acres,  turn  out  its  1,000  and  more  tons 
per  annum.  The  aggregate  planted  area  of  these  twelve  companies 
being  nearly  95,000  acres,  their  future  aggregate  crops  may  amount 
to  19,000  tons  and  more.  If  we  assume  that  15  per  cent,  is  the 
average  loss  on  washing  and  drying  Amazonian  rubber,  this  is 
equivalent  to  21,850  tons  and  more  of  rubber  from  that  source. 

Coming  behind  these  companies,  some  very  close  to  them, 
are  others  with  a  considerable  planted  irea,  and  it  will  be  interest- 
ing to  know  what  crop  of  rubber  per  acre  they  will  require  to  turn 
out  to  ensure  a  total  annual  crop  each  of  1,000  tons.  One  ton  per 
five  acres  is  equivalent  to  440  pounds  per  acre  : — 

Amount 
Present      per  acre 
planted     to  produce 
acreage.    1,000  tons. 

Ceylon  Land  and  Produce  Co 4,900  449 

Lanadron  Rubber  Estates 4.799  458 

Ceylon  Tea  Plantations   4,561  482 

Tandjong  Rubber  Co 4.500  499 

Anglo-Malay  Rubber  Co 4.47^  491 

Tebrau  Rubber  Estates   4.384  502 

London  Asiatic  Rubber  and  Produce  Co 4.371  503 

Straits  Rubber  Co.    .' 4.293  512 

Gula  Kalumpong  Rubber  Estates      4,272  515 

Telogoredjo  United  Plantations 4,i95  524 

F.M.S.  Rubber  Co 4,000  550 

Sialang  Rubber  Estates  3.851  571 

Highlands  and  Lowlands  Para  Rubber  Co 3.840  575 

Jugra  Land  and  Rubber  Estates    3.781  582 

Straits  Settlements  (Bertam)  Rubber  Co 3.556  618 

Lumut  Rubber  Estates    3.332  660 

Sennah  Rubber  Co 3.321  663 

Java  Amalgamated  Rubber  Estates .  .        2.948  746 

In  the  case  of  perhaps  only  two  of  these  companies  can 
it  be  said  that  their  planting  programme  is  completed,  and  it  is  a 
strong  presumption  that  most,  if  not  all,  of  the  remainder  will 
increase  their  planted  areas  sufficiently  to  be  able  to  turn  out  from 
these  areas,  when  mature,  on  the  one  ton  per  five  acres  basis,  as 
much  as  1,000  tons  per  annum.  At  any  rate,  allowing  15  per  cent, 
as  the  loss  on  washing  and  drying  fine  hard  Para,  the  first  seven 
companies  on  this  list  will  each  be  able,  with  their  present  planted 
acreages,  to  annually  turn  out,  on  the  basis  of  i  ton  clean  and 
dry  plantation  rubber  per  5  acres,  rubber  equivalent  to  1,000  tons 
of  fine  hard. 

Can  Plantations  Treble  the  Amazon  Crop  ? 

The  foregoing  statistics  conclusively  show  that  the  future 
importance  of  plantation  rubber  is  one  which  cannot  be  lightly  put 
aside,  if  only  in  view  of  the  possibiUty  of  supplanting  a  good  portion 
of  wild  rubber  by  that  from  plantations.     There  can  be  no  doubt. 


B 


i8  PARA     RUBBER 

even  at  present,  about  the  question  of  economy  in  the  two  classes  ; 
this  is  evidenced  by  the  fact  that  very  many  of  the  wild-rubber 
areas  in  Africa  and  America  are  now  being  gradually  trans- 
formed into  plantations  of  some  kind  or  other.  The  general 
tendency  of  present-day  operations  is  to  commence  or  extend 
regularly  planted  estates  where  wild-rubber  forests  previously 
existed.  In  view  of  all  this  planting  activity,  it  is  advisable  to 
consider  the  capabilities  of  the  areas  already  established  in  the 
East  alone  ;  the  best  comparison  is  furnished  by  a  study  of  the 
present  annual  crop  from  Brazil  and  an  estimate  of  produce  from 
Hevea  estates.  To-day  Brazil  can  claim  rubber  trees  actually 
yielding  say,  40,000  tons  per  annum,  scattered  throughout  immense 
areas  of  dense  forest,  often  in  unhealthy  districts  ;  almost  all  the 
trees  exist  in  the  wild  condition,  very  few  successful  plantations 
being  yet  in  existence.  It  has  already  been  shown  that  the 
output  is  only  equal  to  200,000  acres  of  mature  plantations. 
On  the  other  hand,  there  is  the  plantation  industry  with  about 
800,000  acres  of  planted  trees,  capable  of  yielding  one  to  four 
cwt.  per  acre  per  annum.  The  possibility  of  securing  a  crop  from 
plantations  treble  the  amount  now  annually  obtained  from  Brazil 
may  seem  optimistic,  nay,  even  ridiculous  ;  but  it  may  have  to  be 
faced  before  1920. 

This  huge  plantation  industry  has  been  established  in  about 
ten  years  of  active  estate  work,  is  controlled  by  European  planters 
backed  with  years  of  tropical  experience  and  scientific  advice, 
and  is,  despite  statements  to  the  contrary,  likely  to  undergo 
still  further  extensions  in  the  near  future.  If  Brazil  or  Africa  now 
engage  in  planting  operations,  as  the  East  has  done,  the  result  will 
be  watched  with  natural  anxiety  by  the  planting  community. 
It  should  be  remembered  by  those  contemplating  such  a  programme, 
and  also  by  planters  in  the  East,  that,  whatever  is  planted  after 
1911  can  only  come  into  bearing  after  the  produce  of  800,000  acres 
has  been  placed  on  the  market.  It  is,  therefore,  obvious  that, 
except  labour  is  cheaper  or  plants  grow  more  rapidly  and  yield 
better  in  Brazil  or  Africa,  the  establishment  of  plantations  in 
those  parts  of  the  world  would  not  offer  any  attraction  abo\'e 
estates  already  or  about  to  be  commenced  in  the  East  ;  it  is  also 
clear  that  a  halt  should  be  called  in  planting  extensions  in  the 
latter  area. 

Value  of  Para  Rubber. 

Sufficient  has  been  written  to  give  an  idea  of  past  and  future 
quantities  of  raw  rubber.  It  will  now  be  interesting  to  study 
the  history  of  prices,  especially  that  of  fine  hard  Para  and  planta- 
tion rubber.  The  fluctuation  in  value  of  Para  rubber  during  the 
last  20  years  has  been  great.  In  a  general  way  it  may  be  stated 
that  from  1891  there  was  a  gradual  increase  in  price  from  2s.  yd. 
per  lb.  to  4s.  8d.  per  lb.  in  the  beginning  of  1900  ;  for  the  following 
three  years  there  was  a  decline  until  3s.  3d.  was  reached.  After 
1902,  prices  rose  rather  sharply  until  what  was  then  regarded  as 
the  phenomenal  price  of  5s.  8d.  per  lb.  was  recorded  in  1905. 


PARA     RUBBER  19 

Since  that  year  the  fluctuation  in  value  has  created  a  record  in 
tropical  agricultural  produce  ;  from  1905  to  1908  there  was  a 
gradual  decline  down  to  2s.  gd.,  this  carrying  us  back  to  the 
prices  paid  from  1891  to  1894.  At  about  that  time  the  plantation 
industry  "had  gained  a  footing,  and  those  interested  in  its  develop- 
ment based  their  ultimate  returns  on  an  average  price  of  3s.  3d. 
per  lb.  for  their  produce  when  estates  were  in  bearing.  This  was 
then  quite  a  legitimate  view  to  take.  The  following  two  years, 
however,  completely  changed  the  prospects  of  the  whole  industry. 
Commencing  in  the  early  part  of  1908,  prices  began  to  rise,  and 
before  the  end  of  the  year,  over  5s.  3d.  per  lb.  was  paid  for  fine 
hard  Para.  In  1909  the  demand  for  the  raw  material  was  active 
from  the  beginning  of  the  year  and  became  steadily  stronger  until 
September  and  October,  when  the  highest  prices  were  reached, 
fine  hard  Para  realising  9s.  2d.  and  smoked  plantation  9s.  S^d. 
per  lb.  Nor  was  that  all.  During  the  rest  of  the  year  a  sharp 
decline  to  about  7s.  was  noticed,  but  this  proved  to  be  only  the 
forerunner  of  famine  prices  in  the  following  year.  The  state  of 
the  raw  rubber  market  in  1910  will  be  remembered  for  many 
years  to  come. 

Phenomenal  Prices  during  1910. 

The  fluctuation  in  price  of  fine  hard  Para  and  plantation 
rubber  during  1910  proved  to  be  the  record  in  the  annals  of  the 
industry.  Never,  since  the  year  1827,  when  a  total  export  of  some 
30  tons  was  registered,  has  such  a  variation  in  price  been  recorded 
as  in  1910.  The  variation  during  1910  of  from  7s.  7d.  in  January, 
to  I2s.  8fd.  in  April  of  the  same  year  for  fine  hard  will  be  remem- 
bered as  one  of  the  most  undesirable  rises  ever  known.  It  has 
had  disastrous  results.  The  fluctuation  is  not  likely  to  be  soon 
forgotten.  The  chart  of  The  India-Rubber  Journal,  showing 
the  prices  from  January,  1907,  to  December,  1910,  demonstrates 
the  fluctuating  character  of  our  main  raw  product  ;  the  irregularity 
in  prices  can  undoubtedly  be  regarded  as  phenomenal.  There  is 
absolutely  no  relationship  in  maximum  and  minimum  prices 
with  the  cropping  periods.  In  1907  the  highest  prices  for  fine 
hard  were  in  January,  and  the  lowest  in  November  ;  whereas  in 
1908  the  highest  prices  were  in  November,  and  the  lowest  in 
February.  The  position  was  almost  exactly  reversed  in  two 
consecutive  years.  In  1909  the  highest  prices  were  in  October- 
November,  the  lowest  in  January-February.  During  the  year 
1910  the  highest  was  in  April,  and  the  lowest  in  October.  The 
fact  that  the  highest  prices  have  during  the  years  1907-1910  been 
realised  in  the  months  of  January,  November,  October-November, 
and  April  respectively,  will  always  confuse  economic  prophets 
who  claim  to  be  gifted  with  the  power  to  calculate  future  prices. 
The  irregularity  in  the  price  of  fine  hard  has  been  reflected  in  that 
for  plantation  rubber  from  the  East.  The  absence  of  an  equilibrium 
in  price  is  obvious  from  the  way  in  which  the  premium  on  planta- 
tion during  the  months  of  February  to  June  was  displaced  by  a 
heavy   discount   from   June   practically   up   to   December.     The 


20  PARA     RUBBER 

variation   in    average   price   for   plantation    for    1910   was   from 
5s.  yd.  to  I2S.  8fd. 

High  Prices  and  Increased  Supplies. 
Throughout  the  period  under  review  it  is  to  be  observed 
that  high  prices  had  no  relationship  to  decreased  supplies  ;  in 
fact,  the  higher  prices  during  1903  to  1910  are  coincident  with 
very  large  crops  of  rubber.  This  condition  is,  by  some  students 
of  economics,  regarded  as  abnormal.  The  following  tabulation 
should  prove  instructive  : — 

PARA   RUBBER. 

Year.  Crops.  Prices  per  lb. 

1890      15.354  tons  3/3  to  4/1 

1898      21,908     „  3/7  to  4/5 

1904      28,505     „  4/-  to  5/5 

1905      31,474     ,.  5/-  to  5/8 

1908  36,991  ..  2/9  to  5/3 

1909  39,112  „  5/0  to  9/2 

1910  38,200  ,,  5/6  to  12/9 

1911  37.730  .,  3/9  to  7/1 

Prices  for  Plantation  Rubber. 

The  rise  and  fall  in  the  price  of  plantation  Para  has  generally 
followed  the  fluctuation  in  fine  hard  Para.  During  some  years 
plantation  rubber  has  obtained  a  high  premium  above  the  wild 
product,  especially  for  forms  such  as  block,  pale  crepe,  or  smoked 
sheet,  these  being  paid  for  more  as  novelties  than  as  commercial 
quantities ;  at  other  times  plantation  rubber  has  been  at  a  sub- 
stantial discount.  Probably  the  best  way  to  demonstrate  the 
relationship  between  the  prices  of  the  two  forms  of  Para  rubber 
will  be  to  take  the  fluctuations  throughout  a  typical  year.  If 
we  select  the  year  1909,  we  shall  find  that  from  January  to  May  a 
steady  premium  for  plantation  Para  over  fine  hard  was  main- 
tained— a  difference  of  2d.  between  the  average  prices  being 
general  for  that  period.  A  healthy  premium  was  maintained 
until  the  month  of  August,  when  for  some  reason  plantation  Para 
sold  at  only  7s.  6d.,  while  fine  hard  realised  8s.  3i-d.  Subsequently, 
however,  plantation  rubber  again  estabUshed  itself,  and  towards 
the  end  of  September  and  early  October,  when  fine  hard  Para 
realised  gs.  to  9s.  id.,  plantation  obtained  an  average  price 
gs.  yd.  to  9s.  8d.  per  lb.  A  premium  was  maintained  throughout 
the  rest  of  the  year,  and  in  one  or  two  instances  plantation  marks, 
well  known  to  manufacturers,  obtained  a  premium  of  6d.  per  lb. 
over  the  average  prices  for  rubber  from  adjacent  estates  in  the 
East.  Similar  variability  was  recorded  during  1910,  a  premium 
of  2d.  to  4d.  per  lb.  for  plantation  giving  way  to  a  discount  of  over 
6d.  per  lb.  compared  with  fine  hard  Para. 

Effect  of  High  Prices. 
The  effect  of  the  high  prices  during  1909  and  1910  was  to 
stimulate  the  interest  of  the  general  pubUc  in  the  cultivation 


PARA     RUBBER  21 

of  rubber  plants.  Companies  have  now  been  formed  to  operate 
throughout  the  tropical  belt,  and  it  is  quite  reasonable  to  expect 
that  there  will,  after  making  allowance  for  a  fair  percentage  of 
failures,  be  over  800,000  acres  of  plantations  yielding  rubber  ten 
years  hence  ;  the  amount  of  rubber  likely  to  be  derived  therefrom 
has  already  been  indicated. 

The  condition  of  Eastern  estates,  the  yielding  capacity  of  the 
acreages  now  planted,  and  ■  the  capital  involved,  will  assuredly 
awaken  a  wider  interest  in  this  comparatively  new  and  profitable 
industry.  It  can  be  taken  for  granted  that,  except  something 
unforeseen  happens,  we  shall  have  annually  much  more  rubber 
from  the  East  alone  than  we  have  in  the  past  received  from  the 
whole  of  the  world. 

Every  Eastern  estate  represents  a  centralised  mass  of  trees 
from  which  supplies  of  rubber  can  be  more  rapidly  and  economi- 
cally drawn  than  in  any  other  part  of  the  world.  Every  tree  is 
under  the  personal  supervision  of  trained  European  agricul- 
turists, and  can  receive  daily  attention. 

From  these  facts  it  will  be  clear  that  the  potentialities  of 
the  Eastern  industry  alone  are  such  that  when  the  rubber  is 
arriving  in  fair  quantity,  other  rubbers  of  an  inferior  kind  will 
feel  the  pinch.  Para  rubber  is  acknowledged  to  be  superior  to 
most  other  kinds.  We  have  been  assured  by  some  of  the  most 
prominent  British  manufacturers  that,  if  we  can  supply  them  with 
Para  at  2s.  6d.  per  lb.,  they  will  use  it  in  preference  to  most  African 
and  inferior  American  grades.  A  continuance  of  2s.  6d.  per  lb. 
for  fine  hard  Para  will,  to  a  large  extent,  place  the  world's 
power  in  Eastern  plantations,  for  against  that  price  but  little 
African  and  American  rubber  can  be  exported  under  existing 
circumstances.  At  that  price,  and  with  yields  only  equal  to  those 
obtained  up  to  date,  planters  and  others  engaged  in  plantations 
will  secure  a  very  handsome  profit. . 

The  capital  necessary  to  bring  present  planted  areas  into 
bearing,  and  to  execute  large  extensions  has  already  been  supplied  ; 
the  financial  position  is  sound,  and  we  can  now  proceed  to  consider 
that  side  of  the  plantation  industry. 

Capital  for  Plantations. 

At  my  lecture  before  the  Society  of  Arts,  in  1907,  I  was  able 
to  give  some  indication  of  the  interest  taken,  by  financial  circles, 
in  the  rising  plantation  industry.  The  following  is  a  statement 
of  the  sums  then  invested  in  notable  properties  : — 

MARCH,  1907. 
Paid-up   Capital   of   Rubber-Planting  Companies. 

Malaya 2,048,281 

Ceylon  and  India   415,213 

Islandsin  the  Indo-Malayan  region    651,123 

America 765,000 

Africa 430,000 


22  PARA     RUBBER 

Sterling  equivalent  of  capital  existing  in  rupees 
and  other  local  currency  in' : — 

Malaya    532.748 

Ceylon  and  India   370,566 

Islands  in  Indo-Malayan  region 28,333 

Companies  growing  rubber  in  conjunction  with 

tea,  cacao,  and  other  products    9,121,761 

Grand  total   ;£i4,363.325 


These  figures  kindly  furnished  in  March,  1907,  by  Mr.  Fntz 
Zorn,  at  my  request,  showed  about  five-and-a-quarter  miUion 
sterhng  then  invested  in  rubber  alone.  EngUsh  capital  had  also 
been  invested  in  the  cultivation  and  exploitation  of  rubber  in 
numerous  East  and  West  Indian  islands,  in  tropical  America  and 
Africa,  and  very  large  sums  from  the  Continent  had  then 
been  supplied  for  the  same  purpose. 

The  activity  during  1907  in  new  flotations  •  was  more  pro- 
nounced in  Great  Britain  than  in  any  other  part  of  the  world, 
though  a  few  Mexican  propositions  and  others  emanating  from 
Dutch,  French,  and  German  sources  were  successfully  carried 
through.  In  Central,  West,  and  East  Africa,  Central  and  South 
America,  and  in  the  East  and  West  Indies,  increased  activity-was 
recorded  ;  it  was  then  predicted  that  we  might  during  1908  see 
New  Guinea,  New  Caledonia,  Samoa,  Borneo,  Java,  and  Sumatra 
rise  to  a  position  of  importance  which  very  few  expected,  though 
those  intimately  associated  with  some  of  these  islands,  especially 
the  last  three,  stated  that  the  conditions  for  rubber  cultivation 
were  better  there  than  in  many  parts  of  Ceylon  and  Malaya. 

The  capital  invested  in  rubber  (separate  and  mixed) 
cultivation  up  to  April,  1907,  was  no  less  than  £14,363,325  ;  I  then 
stated  that  ere  long  that  sum  would  be  increased  to  £20,000,000. 
The  following  figures  indicate  new  flotations  during  1907  : — 


1,915,830 

214.333 
1,449,916 
1,050,739 

191,499 

282,449 

3,898,149 

281,707 

;£9. 284,622 

India  and  Burmah,  8  companies .... 
Malaya  24  companies 

Africa,  10  companies    

Tropical  America,  15  companies     .. 
Miscellaneous,  3  companies 

Some  of  these  companies  have  not  been  successful,  but  the 
majority  are  in  working  order  at  the  present  time.  A  few  syndi- 
cates are  included  in  the  above,  and  are  responsible  for  much 
larger  sums  of  money  during  1908. 

1908  :  £2,010,500. 

During  1908  the  nominal  capital  of  companies  registered  in 
Great  Britain  was  £2,010,500. 


PARA     RUBBER  23 

A  number  of  companies  were  also  floated  semi-privately  in 
Ceylon  during  that  period.  Some  of  these  were  the  Ambanad 
Tea  and  Rubber  Co.  (capital  R75o,ooo),  the  Opata  Tea  and 
Rubber  Co.,  etc. 

Compared  with  the  enormous  activity  which  prevailed  the 
previous  year  in  the  rubber  company  world,  these  figures  do  not 
seem  large,  but  they  represent,  nevertheless, a  considerable  addition 
to  the  British  investors'  stake  in  the  rubber  industry.  As  in 
previous  years  the  new  enterprises  were  mainly  British. 

1909  :   £12,008,000. 

The  high  prices  ruling  for  raw  and  plantation  rubber  stimu- 
lated activity  during  1909,  the  total  nominal  capital  of  the  com- 
panies registered  in  Great  Britain,  excluding  finance  companies,  for 
that  year  being  £12,008,000,  or  about  six  times  that  for  1908. 

1910  :   £38,941,500. 

The  high  price  of  raw  rubber  and  the  wild  excitement  prevail- 
ing among  public  speculators  in  plantation  rubber  shares  during 
1910,  resulted  in  the  flotation  of  companies  operating  in  all  parts 
of  the  tropical  zone.  The  year  1910  will  stand  out  as  the  record 
for  all  time  in  respect  of  the  total  nominal  capital  of  such  companies 
registered  in  Great  Britain  ;  it  will  surprise  many  to  learn  that 
this  amounted  to  no  less  than  £38,941,500  for  the  year.  The 
total  for  1908  was  £2,010,500  and  for  1909  £13,671,000  ;  these 
appear  insignificant  compared  with  the  total  for  the  year  1910. 
The  first  quarter  of  the  year  was  responsible  for  £10,021,000,  the 
second  for  £21,130,000  ;  by  that  time  the  position  became  too 
speculative,  but  promoters  managed  to  bring  the  total  for  the  third 
quarter  up  to  £5,120,500  ;  this  was  practically  the  beginning  of 
the  end,  the  last  quarter  only  totalling  £2,670,000. 

These  figures  will  enable  the  reader  to  gain  some  idea  of  the 
efforts  likely  to  be  made  to  further  plantation  companies  in 
different  parts  of  the  world.  If  to  them  is  added  the  capital 
invested  on  the  Continent  of  Europe  and  elsewhere,  it  will  be  seen 
that  the  plantation  industry  has  sufficient  financial  support  to 
enable  it  to  achieve  success. 

1911  :    ABOUT   £6,600,000. 

In  1911  many  difiiculties  were  experienced  by  financial  and 
other  parties  consequent  on  the  fall  in  price  of  raw  rubber  and  the 
downward  tendency  of  most  plantation  companies'  shares.  The 
total  nominal  capital  up  to  the  end  of  the  year  can  be  roughly 
assessed  at  about  £6,600,000.  During  the  second  half  of  the 
year  many  debenture  issues  were  made  and  others  considered. 

Total  Capital  :    £90,000,000. 

The  nominal  capital  of  the  companies  registered  in  Great 
Britain  alone,  during  1907  to  191 1,  therefore  exceeds  £90,000,000, 
including   finance   companies,    a   total   which   guarantees   some 


24  PARA     RUBBER 

measure  of  success.  Nor  is  this  all.  Considerable  capital  has 
been  subscribed  in  Ceylon,  Malaya,  Java,  Sumatra,  Shanghai, 
and  on  the  Continent  of  Europe  during  the  same  period.  Further- 
more, large  sums  have  been  paid  in  subsequent  to  flotation,  as 
premiums  by  the  shareholders. 

Of  course  the  capital  actually  paid  up  is  somewhat  less  than 
this,  and  may  be  estimated  at  about  £60,000,000.  Yet  some 
addition  must  be  made  to  this  with  respect  to  the  debenture 
issues  now  becoming  frequent. 

Details  of  Nominal  Capitalisation,   1908  to  191  i. 

1908.  1909.  1910.  1911. 

£  £  £  i 

Ceylon      265,000  665,000  3,920,000  490,000 

India  and  Burmah      85,000  938,500  970,000  450,000 

Malaya     318,500  5,600,000  8,337,000  2,090,500 

Sumatra 330,000  656,000  2,240,000  1,505,000 

Java     170,000  595,000  5,970,000  660,000 

Borneo     230,000  825,000  3,680,000  200,000 

Africa 120,000  -        507,000  6,064,500  620,500 

Tropical  America 458,500  1,994,000  7,200,000  453,000 

Miscellaneous  Countries     ....  33,500  227,500  460,000  150,000 

;^2, 010,500    ;£i2,oo8,ooo  ;^38,84i,500  £6,619,000 


In  addition  to  the  above,  it  should  be  borne  in  mind  that  over 
£14,000,000  have  been  provided  for  in  finance  companies  from 
1909  to  igii  inclusive. 

Having  dealt  with  the  history  of  rubber  and  past  sources,  it  is 
now  necessary  to  study  the  detailed  history  of  the  plantation 
industry  in  which  such  large  sums  of  money  have  been  invested. 


CHAPTER  II. 

HISTORY  OF  RUBBER  PLANTATIONS 

(  We  are  all  accustomed  to  give  credit  for  plantation  develop- 
ment to  Kew  and  other  botanic  or  agricultural  departments../  Very 
few  people  realise  that,  long  before  even  vulcanization  was  known, 
Hancock  and  his  colleagues  experienced  difficulties  in  procuring 
a  good  supply  of  rubber,  as  they  were  frequently  using  at  the  rate 
of  from  two  or  three  tons  weekly. 

Plantations  recommended  in  1834. 

This,  together  with  the  adulterated  state  of  the  raw  material 
as  it  was  received,  led(Hancock  to  call  attention,  in  the  ' '  Gardener's 
Chronicle,"  to  the  possibility  of  cultivating  the  best  kinds  of 
rubber  plants  in  the  East  and  West  Indies.  That  was  in  1834.I 
Sir  William  Hooker  rendered  him  every  assistance  he  could. 

We  do  not  know  whether  many  have  referred  to  this  sugges- 
tion, which  dated  40  years  prior  to  the  introduction  of  Hevea 
rubber  into  the  East. 

It  was  not,  however,  until  Hevea  brasiliensis  was  selected  by 
Sir  Joseph  Hooker  that  any  development,  worthy  of  being 
recorded,  took  place. 

Collins  procures  Hevea  Seeds  in  1873. 

Six  plants  of  Hevea  brasiliensis  were  sent  from  Kew  to  Dr. 
King,  Botanic  Gardens,  Calcutta,  in  1873,  and  did  not  prove 
satisfactory.  These  were  probably  from  seeds  brought  to  Kew 
from  the  Amazon,  by  Collins,  on  June  4th,  1873.  Collins  after- 
wards became  Government  Economic  Botanist  at  Singapore. 
He  was  author  of  apparently  the  first  real  account  of  the  rubber 
industry  in  South  America  (Report  on  the  Caoutchouc  of  Com- 
merce, by  James  Collins,  1872).  Incidentally  it  should  be  men- 
tioned that  he  described  and  figured  the  herring-bone  system  of 
tapping  ;  invented  several  forms  of  tapping  knife  ;  and  suggested 
the  use  of  iron  vessels  for  collecting  latex  in  place  of  calabashes  or 
leaves  plastered  in  with  clay.  The  non-success  of  CoUins'  plants 
led  to  the  decision  of  Kew  to  send  the  next  Hevea  plants  to  Ceylon 
instead  of  India. 

Seeds  from  Wickham  in  1876. 

'  *  Wickham  relates  how  in  1876  Sir  Jos.  Hooker,  then  director  at 
Kew,  being  attracted  by  drawings  of  the  leaf  and  seed  of  Hevea 
brasiliensis  made  by  him,  did  not  rest  until  he  succeeded  in  inducing 
the  Government  of  India  to  grant  a  commission  for  the  introduction 
of  Hevea,  having  interested  Sir  Clements  Markham,  at  that  time  at 


26  PARA    RUBBER 

the  India  Office, -in  the  project.  Wickham  finally  procured  the 
seeds,  and  in  1876  Kew  was  compelled  to  turn  out  orchid  and 
propagating  houses  to  make  room  for  them  ;  within  a  fortnight  the 
glass  houses  were  filled  with  over  7,000  young  plants. 

Plants  from  Cross  in  1876. 
Cross  was  also  sent  to  South  America  to  bring  home  plants  in 
case  the  transmission  of  living  seed  should  prove  impossible.  He 
arrived  at  Kew  in  November,  1876,  and  brought  with  him  about 
1,080  seedUngs  without  soil,  of  which,  with  the  greatest  care, 
scarcely  three  per  cent,  were  saved  ;  from  these,  about  100  plants 
were  propagated  at  Kew  and  subsequently  sent  to  Ceylon. 

Introduction  to  Ceylon. 

In  1876  nearly  2,000  seedlings  of  Wickham's  stock  were 
despatched  to  Peradeniya,  Ceylon,  from  Kew.  Theje  were  con- 
tained in  Wardian  cases  and  arrived  by  the  ss.  "Duke  of 
Devonshire, ' '  in  excellent  condition. 

The  cost  of  procuring  the  seeds  and  plants,  including  freight 
and  other  expenses,  appears  to  have  been  no  less  than  £1,505  4s.  2d., 
or  an  equivalent  of  about  Rs.  11  for  every  plant  delivered  in  Ceylon. 
The  whole  expenditure  was  borne  by  the  Indian  Government. 
Burmah,  Java,  Singapore,  and  the  \'\'est  Indies  also  received  small 
consignments  from  Kew  direct  in  1876. 

First  Cuttings  and  Seeds  in  Ceylon. 

The  plants  were  first  propagated  from  cuttings,  the  twigs 
from  two  to  three-year-old  trees  being  used  for  this  purpose ;  a 
consignment  of  500  rooted  plants  was  sent,  from  Ceylon,  to  British 
Burmah  and  Madras  in  1878.  , 

The  plants  at  Henaratgocla,  Ceylon,  flowered  for  the  first  time 
in  1881,  when  they  were  five  years  old.  The  plants  at  Peradeniya 
did  not  flower  until  a  few  years  later — 1884 — but  curiously  enough, 
at  Perak  the  smaU  trees  only  35  feet  high  and  2|  years  old  flowered 
in  1880. 

The  trees  at  Peradeniya  did  not  flower  in  1882,  and  only  36 
seeds  were  secured  in  that  year  at  Henaratgoda.  Mr.  Low  sent, 
from  the  Experimental  Garden  at  Perak,  eighteen  seeds  to 
Peradeniya,  but  on  their  arrival  they  were  found  to  be  dead. 

In  1883  no  less  than  nine  trees  flowered  at  Henaratgoda  in 
March,  and  the  fruit  ripened  in  August.  From  this  crop  260 
seedlings  were  raised,  many  of  which  were  sent  to  planters  in 
Ceylon.  In  1884  a  good  crop  of  seed  was  produced  at  Henaratgoda, 
and  over  1,000  seedlings  were  raised  and  distributed  to  officials  in 
suitable  parts  of  the  colony.  In  the  same  year  a  few  seeds  were 
also  produced  for  the  first  time  at  Peradeniya. 

Singapore. 

The  Botanic  Gardens  at  Singapore  received  many  rubber- 
yielding  species  from  Ceylon  and  other  countries.     Mr.  H.N.  Ridley 


PARA     RUBBER 


27 


has  kindly  supplied  me  with  the  following  information  : — Twenty- 
two  plants  of  Hevea  brasiliensis  were  received  on  June  nth, 
1877,  from  Kew,  and  a  further  consignment  was  despatched  from 
Kew  in  the  following  year.  In  1876,  plants  of  Castilloa  elastica  and 
Manihot  Glaziovii  were  received  from  Kew  ;  the  former  were 
failures,  and  the  latter  are  not  looked  upon  with  favour  in  the 
Straits.  In  1898,  plants  of  Funtumia  elastica  and  Mascarenhasia 
elastica  were  received  from  Kew,  but  they  appear  to  grow  very 
slowly.  Plants  of  the  vines  Landolphia  Watsoniana,  L.  Peter' 
siana,  and  L.  Kirkii  were  received  in  1881  fi'om  Kew,  but  none 
have  been  successful  as  cultivated  plants,  though  nearlj^  all  grow 
well.  In  the  same  year  a  species  of  Hancornia,  which  subse- 
quently failed,  was  also  received  from  Kew.  Ficus  elastica,  at 
one  time  largely  cultivated  in  the  Straits  and  Federated  Malay 
States,  was  received  at  Singapore  before  1875.  It  is  a  native  of 
Perak,  and  caoutchouc  from  wild  trees  of  this  species  was  obtained 
before  1876." 

Mr.  Ridley  states  that  the  Straits  do  not  appear  to  have 
obtained  seeds  of  Hevea  brasiliensis  from  Ceylon  until  1886, 
when  they  were  then  distributing  their  own  seeds,  and  he  is  unable 
to  account  for  the  fate  of  the  material  sent  from  Ceylon  in  1877. 
According  to  Ridley,  it  is  clear  from  the  records  of  the  Botanic 
Gardens  and  Murton's  reports,  that  the  cuttings  from  Peradeniya 
were  either  not  received  or  were  dead  on  their  arrival  at  Singapore, 
and  in  1879  the  Botanic  Gardens  did  not  possess  any  living  cuttings 
or  any  plants  except  those  received  direct  from  Kew.  The 
descendants  of  the  healthy  trees  at  the  Singapore  Botanic  Gardens 
cover  immense  areas  in  the  Colony  and  Federated  Malay  States, 
the  islands  of  the  Malay  Archipelago,  East  and  West  Africa, 
Guiana  and  the  West  Indies,  Mexico  and  Polynesia.  As  far  as 
can  be  estimated,  at  least  2,500,000  seeds  and  plants  were  dis- 
tributed to  all  parts  of  the  Tropics  from  these  trees  up  to  the 
middle  of  1909. 

India. 

My  information  regarding  the  introduction  of  rubber-pro- 
ducing species  to  India  has  been  obtained  from  Mr.  J.  H.  Burkill, 
Officiating  Reporter  on  Economic  Products,  Indian  Museum, 
Calcutta.  For  many  years  thousands  of  seeds  of  Hevea  brasilien- 
sis have  been  annually  sent  from  the  Henaratgoda  Botanic 
Garden,  Ceylon,  to  the  Government  of  India,  and  in  addition  to 
these,'  officials  and  planters  have  frequently  secured  seed  supplies 
of  other  species  from  Ceylon  and  the  Federated  Malay  States. 

Six  plants  of  Hevea  brasiliensis  were  first  received  from.  Kew 
in  1873,  but  these  did  not  give  favourable  results  ;  others  were 
received  in  1876,  1877,  and  1879  from  Ceylon.  The  early  results 
obtained  in  India, were  not  encouraging,  and  the  comparative 
failures  then  recorded  had  undoubtedly  considerable ,  influence 
among  planters  in  South  India  especially.  Now;  several  localities 
have  been  proved  suitable,  for  Hevea,  and  regular  consignments 
are  shipped  from  Ceylon  to  Indian  estates.     During  the  last  few 


28  PARA     RUBBER 

years  several  estates  in  South  India  have  been  able  to  collect 
their  own  seeds.  Plants  of  Castilloa  elastica  were  received  from 
Kew  in  1881-1882,  of  Manihot  Glaziovii  in  1877,  of  Funtumia 
elastica  in  1899-1904,  and  of  Landolphia  Kirkii  in  1878-1879. 
All  these,  with  the  exception  of  Manihot  Glaziovii,  are  practically 
valueless  to  planters  in  India  as  sources  of  rubber. 

While  it  is  true  that  Sumatra,  Java  and  Borneo  possess  seed- 
bearing  trees  of  Hevea  brasiliensis,  it  cannot  be  said  that  many 
seeds  have  been  distributed  from  these  islands  to  other  countries. 

At  the  present  time  most  countries  are  in  possession  of  a 
few  seed  bearers,  and  before  long  will  be  independent  of  seed 
supplies  from  other  areas. 

Distribution  of  Rubber  Plants  from  Kew. 

Many  trials  of  Brazilian  species  have  already  been  made  in 
Africa,  East  and  West  Indies,  India,  Malaya,  Borneo,  Philippines, 
New  Guinea,  Fiji,  etc.,  and  of  African  species  in  parts  of  America 
and  the  East  and  West  Indies.  In  the  distribution  of  rubber- 
yiislding  plants  to  various  parts  of  the  world  the  British  Govern- 
ment have  taken  considerable  interest. 

y^  The  gradual  development  of  the  ])lantation  rubber  industry 
'can  be  associated  largely  with  the  activity  of  the  various  Govern- 
ment Botanic  Departments  in  different  parts  of  the  world.  The 
Royal  Gardens,  Kew,  naturally  ranks  of  first  importance  in  this 
respect,  as  a  centre  of  distribution  of  species  collected  from  all 
parts  of  the  tropics.  According  to  the  Kew  Bulletin  (No.  3, 
1907),  Hevea  brasiliensis  was  first  sent  from  Kew  to  India  in  1873  ; 
in  1876  to  Burmah,  Ceylon,  Java,  Singapore,  West  Indies  ;  in 
1877  to  Mauritius  and  West  Africa  ;  and  in  1878  to  Fiji.  Plants  of 
Hevea  Spniceana  were  first  despatched  to  Ceylon  in  1883  ;  to 
India,  Java,  SiVigapore,  West  Africa,  and  West  Indies  in  1887  ; 
and  to  Fiji  in  1893.  Castilloa  elastica  was  first  sent  to  India  in 
1875  ;  to  Ceylon,  Java,  and  \^'est  Indies  in  1876  ;  to  Singapore, 
Mauritius,  and  W'est  Africa  in  1877  ;  and  to  Fiji  in  1882.  Manihot 
Glaziovii  was  first  sent  to  India.  Ceylon,  Singapore,  and  West 
Africa  in  1877;  and  to  Java,  Fiji  and  the  West  Indies  in  1878. 
Landolphia  plants  were  first  despatched  to  Ceylon  and  the  West 
Indies  in  1880  ;  to  Singapore  and  Fiji  in  1881  ;  to  Mauritius  in 
1883  ;  and  to  Java  in  1888.  Funtumia  elastica  was  sent  from 
Kew  to  India,  Ceylon,  Java,  Singapore,  and  the  West  Indies  in 
1896,  and  a  second  consignment  was  forwarded  to  the  same 
countries  in  1897.     That  is  a  magnificent  record,  even  for  Kew.  - 

/ 
Ceylon. 

The  distribution  of  Hevea  seeds  from  Kew,  Ceylon,  and  Singa- 
pore is  an  object  lesson  to  all  who  regard  botanic  departments  as 
being  of  only  ornamental  value.  The  seeds  from  the  parent 
Hevea  trees  raised  by  Trimen  in  Ceylon  and  Cantley  in  Singapore, 
have  been  distributed  throughout  the  world.  The  success  which 
has  attended  the  transmission  of  seeds  has  been  recognised  bv 


PARA     RUBBER  29 

Tesponsible  officers  in  all  parts  of  the  world,  and  remarkable  to 
relate,  thousands  of  Hevea  hrasiliensis  seeds  were  sent  back  to 

■  Brazil,  from  Ceylon,  for  planting  purposes,  during  1906.  The 
various  consignments  have  had  a  varied  fate,  many  arriving  in 
first-class  order,  and  others  proving  a  miserable  failure.  In  the 
latter  category  it  is  recorded  that  out  of  300,000  seeds  sent  to 
Seychelles  in  1907  and  1908,  only  200  plants  were  raised  ;  the 
best  result  was  out  of  a  lot  of  1,000  seeds,  from  Ceylon,  750  plants 
being  raised  therefrom. 

Character  qf  Parent  Plants  in  Amazon. 

Since  the  publication  of  my  first  edition  the  question  of  the 
native  habitat  and  general  character  of  the  origin^  parents  of  East- 
em  Hevea  trees  has  been  frequently  discussed.  /\t  is  well-known 
that  most  of  the  trees  now  in  the  East  are  the  offspring  of  the  seeds 
brought  over  by  Wickham  ;  the  published  accounts  of  that 
•explorer  give  all  the  necessary  details  on  the  interesting  points 
in  question.  Wickham  assures  us  that  the  seeds  were  selected 
from  well-grown  forest  trees,  which  had  given  crops  of  rubber. 
The  trees  often  attained  a  circumference  of  12  feet,  and  rivalled 
all  except  the  largest  trees  in  the  dense  forest.  Hevea  should, 
therefore,  be  regarded  as  a  forest  cultivation.  The  sizes  of  the 
oldest  trees  in  Ceylon  and  Singapore  are  certainly  such  as  to 
warrant  a  wide  distance  in  cultivation.  It  appears  that  all  the 
seeds  came  from  the  same  locality — from  the  high  forest  covering 
the  great  plateaux  stretching  back  from  the  left  bank  of  the 
Rio  Tapajos,  a  tributary  of  the  Amazon.  These  high  plateaux, 
a  few  hundred  feet  above  sea-level,  are  immense  forest-covered 
plains,  and  occupy  ■  the  spaces  between  the  great  arterial  river 
systems  of  the  Amazon  valley.  "They  present  a  more  or  less 
steeply-escarped  face  abutting  on  to  and  above  the  marginal 
plains,  of  varying  width,  and  are  subject  to  inundation  by  the 
backwaters  during  the  annual  rise  of  the  great  river. ' '  So 
thorough  is  the  drainage  of  the  highlands  from  which  the  seeds  were 
gathered  that  the  people  who  penetrate  into  these  forests  for  the 
season's  working  of  rubber  have  to  utilise  certain  water-bearing 
vines  for  their  water  supply,  since  none  is  obtainable  by  surface 
sinking,  in  spite  of  the  heavy  rainfall  during  most  of  the  year.  / 

Wickham  further  states  that  the  soil  in  these  well- drained 
forest  tablelands  is  not  remarkably  rich,  but  deep  and  fairly 
uniform.  It  is,  therefore,  certain  that  as  far  as  elevation,  climate, 
and  soil  are  concerned  there  are  many  Hevea  estates  in  the  East 
where  conditions  compare  very  favourably  with  those  depicted 
by  Wickham.  It  should,  however,  be  stated  that  in  point  of 
distance  in  planting  and  general  cultivation,  planters  in  the  East 
are  not  following  the  recommendations  made  by  Wickham,  who 
believes  in  adopting  forestry  principles  in  the  cultivation  of  Hevea 
brasiliensis. 

Having  traced  the  introduction  of  Hevea  brasiliensis  into 
most  tropical  areas,  we  can  now  proceed  to  consider  the  evolution 

■  of  plantations  in  each  country  of  importance. 


30  PARA     RUBBER 

Labour  Costs  and  Planted  Acreages. 
Before  proceeding  to  detail  the  progress  of  planted  acreages 
it  is  advisable  to  remark  that  the  comparative  costs  of  coolie 
labour  in  various  parts  of  the  East  have  played  an  important 
part  in  the  progress  of  planted  acreages.  All  countries  in  the 
East,  except  South  India  and  Java,  appear  to  have  been  largely 
dependent  upon  imported  coolies  for  the  establishment  and 
upkeep  of  their  estates.  Ceylon  secures  its  labour  from  India  ; 
Malaya  from  India,  Java,  and  China  ;  Sumatra  and  Borneo  from 
Java  and  China.  In  each  country  the  native  population  can  also 
be  drawn  upon  especially  for  clearing  operations,  notably  Battaks 
in  Sumatra,  arid  Singhalese  in  Ceylon.  Recently,  Ferguson  (Sou- 
venir, I.R.J. ,  1909)  pointed  out  that  in  this  chief  factor  of  labour 
supply  Ceylon  will  always  have  great  advantages.  Its  close  prox- 
imity to  the  ,  coolie  districts  of  southern  India,  and  the  great 
improvement  in  transport  which  the  Indo-Ceylon  Railway,  with 
steam  ferry  now  sanctioned,  will  afford,  must  tell  greatly  in  favour 
of  Ceylon  rubber  plantations.  But,  in  addition,  it  is  found  already, 
and  will  be  increasingly  seen  as  time  runs  on,  that  the  Singhalese, 
in  many  districts,  will  be  quite  ready  to  take  service  for  such  simple, 
and  to  them,  interesting  work  as  is  involved  in  the  harvesting,  the 
collection  of  the  latex  and  the  preparation  of  the  same  in  the 
factory.  The  average  daily  cost  of  coolie  labour  in  Ceylon 
compares  favourably  with  other  countries,  especially  Malaya, 
Borneo,  and  Sumatra. 

The  West  Indies,  tropical  America  and  many  parts  of  Africa 
include  areas  which,  so  far  as  soil  and  climate  are  concerned,  are 
well  suited  for  the  growth  of  rubber  trees  ;  the  scarcity  of  labour 
and  its  high  cost  prevent  extensions  being  made  on  a  large  scale, 
and  to  these  factors  must  be  attributed  the  small  acreages  of 
cultivated  rubber  trees  in  the  countries  mentioned. 

Even  at  the  present  time  in  the  East  the  effect  of  increased 
labour  costs  is  making  itself  felt ;  on  many  Malayan  and  Sumatra 
estates  where  coolies  cost  quite  one  shilling  per  day  extensions 
cannot  be  undertaken  as  light-heartedly  as  in  parts  of  Ce\-lon, 
Java,  and  South  India,  where  labour  is  much  cheaper. 

Area    for    Rubber  in   Ceylon. 

It  appears  that  in  a  circular  of  the  Royal  Botanic  Gardens, 
Ceylon,  in  1898,  the  land  most  suitable  for  Hevea  cultivation  was 
described  as  that  at  about  sea-level :  the  area  of  land  suitable  for 
profitable  rubber  cultivation,  in  Ceylon,  being  then  assessed  at 
not  more  than  10,000  acres.  As  in  a  further  circular  (1899)  it 
was  stated  that  "there  is  not  very  much  suitable  land  in  the 
colony  in  which  this  cultivation  is  likely  to  prove  really  successful, ' ' 
and  this  is  repeated  by  other  authorities  so  late  as  1906  (Lectures 
on  Indiarubber,  page  154),  it  seems  necessary  to  draw  particular 
attention  to  the  erroneous  advice  originally  given.  The  area 
under  Hevea  in  Ceylon  is  already  twenty  times  that  originally 


PARA     RUBBER  31 

described  as  suitable,  and  a  considerable  portion  of  the  plantations 
will,  in  all  probability,  yield  fair  crops  of  rubber. 

Ceylon   Acreages. 

The  development  of  rubber  plantations  in  Ceylon  has  been 
rapid,  though  not  quite  so  phenomenal  as  in  Malaya.  In  1890 
Ceylon  had  only  300  acres  under  rubber  ;  in  1900,  1,750  acres  ; 
in  1902,  4,500  acres  ;  and  in  1904,  about  25,000  acres.  After  that 
year  planters  were  attracted  by  the  improved  growth  and  yield 
in  many  parts  of  the  island  and  the  acreages  showed  very  rapid 
increases,  they  being  in  1905,  40,000  acres  ;  1906,  100,000  acres  ; 
1907,  150,000  acres  ;  1908,  170,000  acres  ;  1909,  174,000  acres  ; 
and  in  the  middle  of  1910,  188,000  acres.  Of  the  174,000  acres 
under  rubber  in  1909,  no  less  than  131,800  were  in  separate 
clearings,  the  rest  being  intermixed  with  other  products.  These 
areas  have  been  calculated  from  a  statement  of  actual  acreages 
and  numbers  of  trees,  150  trees  being  estimated  to  the  acre 
and  an  allowance  also  being  made  for  intercrops.  As  a  matter 
of  fact,  in  the  middle  of  1910  rubber  was  scattered  over  238,000 
acres,  of  which  95,500  acres  were  associated  with  tea  or  cacao.  It 
is  only  fair  to  assume  that  Hevea  will  outlive  the  interplanted 
products. 

It  is  of  interest  to  note  that  the  leading  rubber-growing 
districts  in  Ceylon  were,  in  1909  and  1910,  in  their  order  according 
to  acreage,  viz.  : — Kelani  Valley,  Kalutara,  Ratnapura,  Kegalla, 
Galle,  Kurunegala,  Matale  East,  Matale  North,  Matale  West, 
Haputale,  Monaragala,  Madulsima,  Matale  South,  Rakwana, 
Kadugannawa,  Alagalla,  Nilambe,  Ambagamuwa,  Passara,  Dolos- 
bage  and  Galagedara.  Kelani  Valley  then  returned  30,321  acres 
rubber  alone,  beside  22,839  tea  and  rubber  ;  Kalutara,  29,902 
and  12,016  respectively  ;  Ratnapura,  12,963  and  2,352  ;  Kegalla, 
10,000  and  3,437  ;  and  Galle,  7,322  and  2,327 — to  name  only  the 
first  five  districts. 

RuBBEit    Acreages    in   South  India  and  Burmah. 

Though  Calcutta  was  the  first  to  receive  plants  of  Hevea  from 
Kew,  in  1873,  the  acreage  under  this  species  in  the  whole  of  India 
is  small  when  compared  with  Ceylon  or  Malaya.  In  a  recent 
document  regarding  South  India  it  is  stated  that  Travancore 
heads  the  list  with  18,251  acres,  Malabar  is  credited  with  from 
6,000  to  7,000  acres,  Cochin  with  3,736  acres,  the  Shevaroys  with 
1,829  acres,  and  Mysore  with  2,000  acres  ;  with  the  exception  of 
Mysore  the  plants  are  mainly  Hevea  hrasiliensis.  The  total  acreage 
under  rubber  of  all  kinds  in  South  India  is  approximately  42,000 
acres,  but  this  must  not  be  regarded  as  the  equivalent  of  the  same 
acreage  in  other  countries,  owing  to  some  estates  having  their 
Hevea  trees  growing  at  high  altitudes  and  under  unsuitable 
climatic  and  soil  conditions.  The  United  Planters'  Association 
of  Southern  liidia  estimated,  in  1910,  that  there  were  29,546 
acres  under  rubber  and  that  a  crop  of  179)400  lb.  would  be  exported 
in  rhat  year. 


32  PARA     RUBBER 

The  handbook,  ' '  Rubber  in  South  India, ' '  distributed  at  the 
last  exhibition  in  London,  gave  the  acreages  in  Travancore  and 
Cochin  as  follows  : — nine  years  old,  200  acres  ;  seven  years, 
701  acres  ;  six  years,  1,831  acres  ;  five  years,  5,259  acres  ;  four 
years,  4,498  acres  ;  three  years,  4,164  acres  ;  two  years,  i,59° 
acres  ;    one  year  old,  3,615  acres.     The  total  was  21,988  acres. 

There  are,  at  high  elevations  in  India,  about  5,000  acres  of 
Hevea,  not  including  that  in  Coorg,  Mysore  and  Wynaad.  It  is 
mostly  planted  amongst  or  interplanted  with  coffee,  some  of  the 
trees  being  nine  and  ten  years  old.  This  hill  rubber  is  at  varying 
elevations  from  a  httle  under  2,000  to  3,700  feet  above  sea-level, 
the  rate  of  growth  varying  according  to  elevation.  It  may  be  laid 
down,  according  to  Windle,  that  at,  say,  3,500  feet  above  sea- 
level,  a  tree  will  not  be  of  a  tappable  size  before  seven  years  in  a 
dry  district  and  a  year  or  so  less  in  a  moist  one. 

In  1908  rubber  in  Burmah  was  reported  to  total  about  4,500 
acres  in  Mergui,  Tavoy  and  Shweggin  districts  and  in  Rangoon  (not 
including  small  holdings  of  Chinese  and  Burmans)  ;  there  were 
also  plantations  in  Yonngoo,  Bosseim,  Amherst  and  Bhamo. 

Acreage  Planted  in   Malaya. 

Carruthers  pointed  out  that  in  1897,  rubber  estates  only 
covered  350  acres  in  Malaya  ;  10  years  after  they  had  increased  by 
360  times.  In  1902  less  than  7,500  acres  had  been  planted  ;  five 
years  after  17  times  that  amount  was  under  rubber.  Nearh'  all 
this  was  virgin  jungle  prior  to  its  being  planted  with  rubber, 
and  had  to  be  cleared  before  any  planting  operations  could  be 
begun.  Nine-tenths  of  the  whole  acreage  has  been  cleared  and 
planted  by  the  younger  generation  of  planters,  who  deserve  the 
greatest  credit  for  the  excellent  way  in  which  their  work  has  been 
carried  out. 

Malaya  in  1906  :  99,230  Acres. 
This  year,  in  the  F.M.S.  alone,  a  total  of  150,000  acres  was 
reported  as  alienated  for  rubber  cultivation.  Carruthers  estimated 
that  the  planted  area  comprised  25,000  acres  under  one  year  old  ; 
15,000  acres,  one  to  two  years  ;  4,500  acres,  under  three  years  ; 
4,000  acres,  under  four  years  ;  and  8,500  acres,  under  five  years. 
The  total  acreage  in  Selangor  was  given  at  44,821  acres,  Negri 
Sembilan  at  10,600  acres,  Perak  29,600  acres,  and  Pahang  4S3 
acres,  for  the  end  of  December,  1906,  by  the  then  Director  of 
Agriculture.  The  total  areas  for  Straits  Settlements,  under 
rubber,  was  given  at  11,341  acres,  and  Johore  2,310  acres,  making 
the  total  for  Malaya  99,230  acres  in  December,  1906.  These 
statistics  do  not  entirely  agree  with  those  given  in  the  Straits 
Settlements  Blue  Book  ;  the  same  remark  applies  to  the  figures 
for  the  years  1907  to  1909  inclusive. 

Malaya   in    1907 :  179,227  Acres. 
It  is  interesting  to  notice  at  that  time  (1906)  how  close  was 
the  competition  between  Ceylon  and  Malaya  to  have  the  largest 


PARA     RUBBER  33 

planted  acreage  under  rubber.  Carruthers'  estimate  of  the 
planted  acreage  in  the  F.M.S.,  Johore,  the  Straits  Settlements,  and 
Kedah,  for  December,  1907,  was  179,227  acres. 

The  rubber  acreage  (126,235  acres)  in  the  F.M.S.  was  made 
up  of  61,552  acres  in  Selangor,  46,167  acres  in  Perak,  17,656  acres 
in  Negri  Sembilan,  and  860  acres  in  Pahang. 

Selangor  had  124  estates  with  9,648,093  trees,  and  planted 
19,135  acres  during  1907  ;  Perak  had  114  estates,  6,648,957  trees, 
with  16,050  acres  planted  in  1907 ;  Negri  Sembilan  had  34 
estates,  3,165,388  trees,  with  4,945  acres  planted  in  1907,  and 
Pahang  brought  up  the  rear  with  15  estates,  166,590  trees,  and 
only  193  acres  were  planted  in  1907. 

The  land  alienated  for  rubber,  declared  Carruthers,  was  nearly 
four  times  as  much  as  that  actually  growing  rubber. 

The  rapid  progress  of  the  rubber  industry  in  Malaya  during 
1907  is  shown  by  the  fact  that  at  the  end  of  the  year  45,764  more 
acres  of  rubber  land  had  been  planted,  an  increase  of  about  46  per 
cent,  on  the  total  of  the  previous  year.  The  number  of  trees  in 
1906  was  under  13,000,000,  and  in  1907,  27,558,400,  a  large 
acreage  being  planted  closer  than  before. 

Malaya   in    1908 :   241,138   Acres. 

Further  progress  was  reported  in  planting  operations  through- 
out Malaya  in  1908.  It  was  stated  that  at  the  end  of  1908  there 
were  37,440,020  trees  as  compared  with  27,558,369  a  year  before  ; 
60,636  acres  were  planted  during  1908,  an  increase  of  over  33  per 
cent,  on  the  previous  year,  giving  a  total  of  241,138  acres  of 
rubber  on  the  31st  December  for  the  whole  Peninsula. 

The  advance  in  rubber  planting  in  the  Federated  Malay 
States  alone  was  as  rapid  in  1908  as  in  1907  ;  41,813  acres  were 
planted  during  the  year  as  compared  with  40,743  in  1907,  an  increase 
of  33  per  cent.  On  the  31st  December,  1908,  there  were  168,048 
acres  of  rubber,  containing  26,165,310  trees,  in  the  Federated 
Malay  States  alone,  as  against  126,235  acres  and  19,628,957  trees 
on  the  same  date  of  the  previous  year.  The  balance  of  the 
acreage  to  make  up  the  total  given  above  was  situated  in 
the  Straits  Settlements. 

Malaya  in  1909  :  292,035  Acres. 

There  were  only  28,905  acres  of  Hevea  planted  in  the  F.M.S. 
during  1909,  as  compared  with  41,813  planted  during  1908,  the 
decrease  in  rate  of  planting  being  especially  noticeable  in  Selangor 
and  Negri  Sembjlan.  In  the  whole  of  the  Peninsula  there  were 
50,897  acres  planted  during  1999,  as  against  60,636  acres  in  1908. 
In  the  total  acreage  for  the  F.M.S. — 196,953  acres — Selangor  is 
credited  with  93,853  acres,  Perak  with  68,278  acres,  Negri  Sembilan 
with  31,945  acres,  and  Pahang  with  2,877  acres. 

Malaya  in  1910  :  400,000  Acres, 

The  figures  for  1910  show  that  very  rapid  strides  were  made 
by  planters  in  almost  every  part  of  Malaya.     The  area  opened  in 


34  PARA    RUBBER 

the  F.M.S.  alone  was  48,813  acres,  against  28,905  acres  in  1909. 
In  a  recent  return  (Straits  Bulletin,  February,  1911),  compiled 
through  the  courtesy  of  land  officials,  an  approximate  acreage  under 
rubber  at  the  end  of  1910  was  given  for  Malacca  at  55,000  acres. 
Province  Wellesley,  22,900  acres,  Singapore,  14,000  acres,  and 
Penang,  3,000  acres,  a  total  of  nearly  100,000  acres.  In  the 
Annual  Report, of  the  Director  of  Agriculture,  Kuala  Lumpur,  for 
1910,  the  acreage  of  rubber  is  given  at  362,853  for  Malaya,  the 
Straits  Settlements  being  credited  with  60,568  acres  in  compiling 
that  estimate.  It  is  clear  from  the  above  that  the  Straits  Settle- 
ments can  be  assessed  at  nearly  100,000  acres,  thus  bringing  the 
total  acreage  in  Malaya  in  1910  to  approximately  400,000  acres. 

Comparison  for  Five  Years  in  Malaya. 
It  is  obvious  that  the  years  1906,  1907,  1908,  1909,  and  1910, 
were  responsible  for  systematic  progress  in  rubber  cultivation 
throughout  Malaya,  and  as  during  the  next  two  to  three  years 
heavy  crops  will  be  forthcoming  from  these  areas,  it  will  be  of 
interest  to  give  a  comparative  statement  showing  the  approximate 
acreages  of  trees  planted  each  year  in  the  respective  districts  : — 

Acres  under  Rubber  in  Malaya. 
Year.        Federated  Straits 

Malay  States.   Settlements. 

1906  85,579      11,341 

1907  126,235  42,866 

1908  168,048  50,121 

1909  196,953  57.587 

1910  245,774  60,568 

It  is  also  of  interest  to  note  the  increase  in  number  of  trees 
during  the  same  period,  official  estimates  assessing  these  as 
follows  : — 1906,  12,325,904  trees  ;  1907,  27,258,440  trees  ;  1908, 
37,440,000  trees.  Calculating  the  number  of  trees  at  the  rate  of 
150  per  acre,  we  should  have  approximately  45,000,000  and 
60,000,000  in  1909  and  1910  respectively.  It  is  now  becoming 
quite  common  to  thin  out  closely  planted  areas  ;  from  this  and 
other  causes  it  appears  reasonable  to  estimate  a  reduction  to 
40,000,000  trees  on  the  total  Malayan  acreage  for  1910. 

Malaya  takes  Premier  Position. 

It  will  be  instructive  to  compare  the  planted  acreages,  under 
Hevea,  in  the  two  leading  countries — Ceylon  and  Malaya  : — 

Ceylon.  Malay  Peninsul 

(Middle  of  each  year.)  (End  of  each  year.) 
Year.                                   Acres.  Acres. 

1897      650  350 

1902      4.5°°  7.500 

1903      7.500  — 

1904     25,000  

1905  ,  ■ 40,000  38.000  (estimated) 

1906  100,000  99,230 

1907  150,000    .  179,227 

1908  170,090,  241,138 

1909  174,000  292,035 

1910  188,000  400,000 


Johore. 

KeHntan  & 
Kedah. 

Total. 

2,310 

— 

99.230 

10,126 

— 

179.227 

20,944 

2,025 

241,138 

33.344 

4,151 

292,035 

43.516 

12.995 

362,853 

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PARA    RUBBER  33 

It  will  be  readily  understood  that  the  statistics  here  given  are 
approximate  only.  The  figures  for  Ceylon  can  be  increased  by 
the  equivalent  acreage  over  which  a  large  number  of  trees  are 
planted,  but  for  which  no  actual  acreage  is  given.  The  figures 
given  in  the  third  column  refer  not  to  the  rubber  acreage 
in  the  Federated  Malay  States,  but  also  to  the  areas  planted 
in  Malacca,  Wellesley,  Johore  and  Kelantan.  When  one 
takes  into  account  the  fact  that  the  Ceylon  statistics  relate 
to  planted  acreages  as  at  the  middle  of  each  year,  it  will 
be  seen  that  the  planted  acreages  at  the  end  of  each  year  more 
or  less  closely  approximated  to  one  another  for  a  number  of  years, 
but  later  Malaya  began  to  go  ahead.  A  large  portion  of  the  Hevea 
acreage  in  Ceylon  is  associated  with  other  products  ;  this  con- 
dition, though  it  may  lengthen  the  life  of  the  rubber  trees  in 
Ceylon,  will  alone  account  in  the  future  for  a  much  lower  yield, 
per  acre,  per  annum.  It  may  be  stated,  if  interplanted  areas 
are  included,  that  in  Ceylon,  in  1911,  there  was  a  little  more 
than  half  the  total  acreage  under  Hevea  in  Malaya;  this  may 
mean  that  double  the  quantity  of  rubber  from  Ceylon  may  be 
annually  expected  from  the  latter  area  in  future  years. 

Rubber  in   Cochin   China  and   Annam. 

The  French  have  done  their  best  to  encourage  rubber 
growing  in  these  colonies  by  starting  experimental  areas,  while 
private  effort  has  been  devoted  to  the  planting  of  Hevea.  The 
area  in  Cochin  China,  at  the  end  of  1910,  was  12,150  acres,  with 
1,759,700  trees.  There  were  886,000  trees  in  the  nurseries,  and  it 
is  anticipated  that  8,265,000  trees  will  ultimately  be  planted.  In 
Annam  the  cultivation  is  not  so  far  advanced. 

Rubber    in     Siam. 

H.M.  Consul  at  Senggora  (Siam)  stated  in  1909,  that  the  only 
foreign-owned  rubber  plantation  in  the  Monthon  of  Patani  was 
near  Bangnara.  It  was  owned  by  an  Englishman  and  was  started 
about  four  years  ago.  Reports  with  regard  to  it  are  favourable, 
and  the  Consul  calls  the  attention  of  persons  interested  in  rubber 
to  the  possibilities  of  Patani  as  a  rubber-producing  country. 

Sumatra    Acreages. 

In  1908  it  was  pointed  out  that  rubber  was  grown  on  44 
estates  in  Sumatra,  17  being  in  the  Serdang  and  7  in  the  Langkat 
districts.  The  Padang,  Bedagai,  Batoe  Bahara,  and  Asahan 
districts  were  also  represented. 

Fourteen  coffee  estates  of  the  above,  on  account  of  the  lowered 
commercial  value,  of  that  product,  planted  rubber  ;  rubber  and 
cofiee  in  conjunction  take  up  19  estates  ;  coffee-coconuts-rubber, 
2  estates  ;  tobacco-rubber,  4  estates  ;  tapioca-rubber,  2  estates  ; 
rubber-coffee-tobacco,  i  estate  ;  coffee-rubber-tobacco,  i  estate  ; 
coconuts-rubber,  i  estate,  and  groundnuts-rubber,  i  estate,  makeup 
the  remainder.  From  enquiry  made,  the  "  Ceylon  Observer  "learned 
that  the  acreage  under  rubber  cultivation  on  the  East  Coast  of 


36  PARA    RUBBER 

Sumatra  was  estimated  in  December,  1907,  at  20,800  acres.  It  is 
now  80,000  acres,  of  which  over  70,000  acres  are  Hevea  rubber. 

Enghsh  corripanies  operating  in  Sumatra  own  approximately 
50,000  acres.  It  is  assumed  that  they  possess  about  half  the  total 
acreage  under  Hevea  rubber  in  that  country  at  the  present  time, 
activity  being  mainly  manifest  in  the  Serdang,  Langkat,  and 
Asahan  residencies.  Many  large  estates  are  owned  by  the  Dutch, 
but  the  statistics  of  their  Hevea  acreages  are  not  available. 

The  most  striking  development  in  Sumatra  of  recent  years 
is  the  acquirement  of  extensive  areas  by  an  American  company 
working  through  subsidiaries.  Some  120,000  acres  have  been 
taken  over,  of  which  20,000  were  expected  to  be  planted  before 
1912. 

Rubber  Acreage  in  Java. 

Hevea  in  Java  is  being  mainly  grown  from  sea-level  up  to 
1,000  feet-;  there  are  estates  up  to  2,200  feet  where  this  species 
is  flourishing,  but  they  are  not  very  numerous.  In  many  districts 
there  is  a  marked  dry  season  of  many  months'  duration,  and  in 
others  a  more  or  less  continuous  and  abundant  rainfall.  Estates 
I  have  visited  had  an  annual  rainfall  of  from  70  to  over  200  inches  ; 
the  dry  period  lasting  three  to  five  months  in  each  year.  The 
majority  of  the  plantations  are  young,  extensive  clearings  dating 
from  1905  and  1906. 

A  few  estates  planted  in  1906  and  maintained  in  Hevea  alone 
will  be  harvesting  their  rubber  in  1912,  but  others  interplanted 
with  various  crops  will  be  a  little  later. 

Van  Bennekom  states  that,  according  to  official  figures,  it 
may  be  accepted  that  the  following  were  the  areas  at  the  end 
of  August,  1910  : — 

Hevea  brasiliensis       ..  .,  ..      about  47,500  acres 

Ficus  elastica  ..  ..  ..  ,,       31,000.   „ 

Hevea,  Ficus,  Castilloa,  Ceara  .  .  ,,       32.000    ,, 

We  may  safely  assume  that  in  1910-11  there  were  planted  : — 

Hevea  brasiliensis       ..  ..  ..      about  45,000  acres 

Ceara  and  other  Manihots       ..  ..  ,,         5,000 

He  then  assumes  that,  at  about  the  middle  of  1911,  about 
160,000  acres  were  planted  with  rubber  in  Java. 

In  January,  1910,  the  following  was  the  distribution  of  the 
estates,  with  their  planted  acreage,  according  to  residencies. 
Bantam,  11  estates,  5,368  acres  ;  Batavia,  13  estates,  6,490  acres  ; 
Preangfr,  13  estates,  11,180  acres;  Cheribon,  4  estates,  2,710 
acres  ;  Tegal,  i  estate,  175  acres  ;  Samarang,  16  estates,  6!o34 
acres  ;  Soerabaya,  3  estates,  1,211  acres  ;  Pasoeroean,  41  estates, 
2p,475  acres ;  Besoeki,  25  estates,  15.317  acres ;  Banjoemas^ 
8  estates,  5,535  acres  ;  Kediri,  12  estate?,  5,118  acres  ;  Soerakarta^ 
10  estates,  6,2,05  acres. 


PARA    RUBBER 


37 


Hevea  in  British  Borneo. 

The  late  Mr.  Cowie  informed  me  that  the  total  acreage  under 
rubber  at  the  end  of  1907  was  approximately  3,600  acres. 

This  country  has  made  good  process  since  then  in  planted 
acreage  under  Hevea.  It  was  estimated  that  there  were  about  12,000 
acres  planted  on  the  ist  January,  1911.  The  following  particulars 
indicate  the  approximate  acreages  planted  during  and  since  1906  : — 

Year.  Area. 

1906  1,240  acres. 

1907  2,823 

1908  3,380      ,. 

1909  4,992      ,, 

Total        12,435  acres. 

A  part  of  this  acreage  was  planted  with  tobacco,  but  it  is 
anticipated  that  such  ground  or  land  equal  to  the  acreage  under 
tobacco  on  the  same  estates  will  be  planted  with  Hevea. 

Figures  are  not  available  in  the  case  of  Dutch  Borneo. 

New  Guinea  and  Queensland. 

Owing  to  the  influx  of  capital  to  this  country  it  is  possible 
that  rubber  cultivation  may  soon  gain  a  sound  footing  in  British 
New  Guinea.  Wickham  has  reported  on  the  prospects  of  rubber 
planting  in  that  area.  An  illustration  (I.R.J.,  February  21st, 
1910),  of  a  young  Hevea  tree  in  Papua  indicates  that  fair  growth 
may  be  obtained  on  selected  soils.  Bloomfield  is  convinced 
that  rubber  planting  will  become  a  successful  industry  in  the  wet 
belt  of  Papua,  and  writes  that  Hevea  plants  from  Ceylon  seed 
have,  in  some  cases,  attained  a  height  of  22ft.  in  15  months  from  the 
date  of  planting  out. 

During  the  past  few  years  the  planting  of  rubber  trees  in 
German  New  Guinea  has  proceeded  on  a  large  scale.  The  progress 
of  the  plants  has  hitherto  shown  that  the  climate  promises  well 
for  Castilloa  elastica,  Ficus  elastica,  and  Hevea  brasiliensis.  A 
large  number  have  not  yet  reached  the  age  for  tapping,  although 
some  tons  of  rubber  are  now  being  harvested. 

Preuss  records  that  the  oldest  plants  of  Hevea  brasiliensis 
can  now  supply  abundant  quantities  of  seed. 

In  January,  191 1,  the  total  planted  acreage  in  German 
New  Guinea,  was  estimated  by  an  official  publication  at  6,036 
acres,  made  up  as  follows  :  Hevea,  1,144  acres  ;  Ficus,  4,237 
acres  ;  Castilloa,  639  acres  ;  Kickxia  (Funtumia) ,  15  acres  ;  Mani- 
hot,  I  acre. 

Queensland  is  evincing  activity  in  so  far  that  a  number  of 
settlers  are  selecting  land  and  applying  for  Hevea  and  other 
plants  from  the  State  nursery. 

Samoan  Rubber  Developments. 

Samoa  appears  to  be  attracting  attention  among  several 
Continental  firms  interested  in  the  cultivation  of  rubber  plants! 
At  the  present  time  there  are  only  two  or  three  very  large  companies 


38  PARA    RUBBER 

which  are  concerned  exclusively  with  rubber  cultivation,  a.na 
these  are  yet  in  their  infancy.  There  are,  however,  according 
to  Preuss,  several  small  rubber  estates  which  have  existed  for 
a  few  years.  The  Samoan  people  have  already  secured  plants 
of  Hevea  brasiliensis,  Castilloa  elastica,  Castilloa  elastica  vanetj' 
Alba,  Ficus  elastica,  Ficus  Riga,  Funtumia  elastica,  and  Urceola 
elastica.  A  fair  number  of  rubber- yielding  species  of  repute  are. 
available  for  experiment  and  subsequent  selection. 

A  British  company,  the  Upolu  Rubber  and  Cacao  Company, 
Ltd.,  has  already  some  550  acres  of  Hevea  rubber  under  cultivation, 
with  cacao  interplanted. 

The  Upolu  Rubber  Co.,  Ltd.,  amalgamated  with  the  former 
owns  a  considerable  area  under  Hevea. 

A  large  area  adjoining  this  plantation  has  been  cleared  by 
the  Safata  Samoa  Gesellschaft  for  rubber  culture  ;  the  company 
is  also  planting  rubber  through  its  cacao. 

The  BerUn  Caoutchouc  Company  is  vigorously  pushing  on 
its  work  at  Saluafata,  20  miles  from  Apia,  having  leased  from  the 
natives  a  tract  of  land  measuring  several  thousand  acres. 

From  400  to  500  acres  have  been  planted  with  cacao,  coco- 
nuts and  rubber  by  Messrs  Gurr  and  Moors,  the  former  having 
350  acres  under  cultivation. 

The  planted  acreage  under  rubber  in  Samoa  was,  in  1909, 
1,507  acres  ;  of  this,  1,418  acres  were  Hevea.  Tapping  is  expected 
to  commence  on  Alisa  and  other  plantations  this  or  next  year. 

Rubber  in  Hawaii,  etc. 

Rubber  cultivation  in  Hawaii  continues,  according  to  Evans, 
to  be  vigorously  pushed  forward,  and  there  are  now  several  local 
companies  in  operation.  The  present  area  under  cultivation  is 
about  1,325  acres,  the  greater  part  of  which  is  situated  on  the 
windward  side  of  the  island  of  Maui.  The  oldest  trees  are  about 
fifteen  years  of  age.  Hevea  brasiliensis,  Castilloa  elastica,  Manihot 
Glaziovii,  and  Ficus  elastica  have  all  been  given  a  trial.  The 
favourite  and  the  one  most  suited  to  local  conditions  is  undoubtedly 
Maniho  ;  next  in  order  of  suitability  comes  Hevea.  Ficus 
elastica  is  quite  unsuitable,  and  it  is  improbable  that  Castilloa 
will  prove  of  any  local  iniportance.  In  certain  districts  in- 
dividual trees  of  Castilloa  are  doing  well,  but  the  general  health 
and  growth  does  not  compare  well  with  trees  of  the  same  age  in 
other  rubber  countries. 

Although  climatic  conditions,  coupled  with  the  high  price 
of  labour,  will  prevent  the  territory  of  Hawaii  from  ever  becoming 
a  first-class  rubber-growing  centre,  there  is  evidence  that  in 
certain  districts  on  Maui  and  Hawaii  a  limited  supply  of  good 
quality  rubber  can  be  produced  at  a  profit,  providing  there  is  no 
serious  drop  in  present  market  prices. 

Several  planters  in  Fiji  and  the  Solomon  Islands  have  evinced 
interest  in  rubber  cultivation,  but  very  Uttle  progress  has  been 
so  far  made  with  plantations  of  Hevea  brasiliensis. 


PARA     RUBBER  39 

Seychelles. 

Seychelles  can  now  boast  of  being  able  to  secure  supplies 
of  Hevea  seeds  from  its  own  plants,  a  few  hundred  trees  having 
reached  the  seeding  and  tapping  stage.  The  best  trees  in  1909 
had  a  circumference  of  30  inches,  and  were  six  years  old.  The 
Seychelles  islands  being  between  latitudes  4°  and  5°  South,  are 
favourably  situated  for  rubber  growing.  One  company  reported 
on  the  30th  June,  igii,  that  270  acres  had  been  planted  with 
52,000  Hevea  trees  ;  another  expects  to  have  over  400  acres  planted 
by  the  end  of  this  year. 

Rubber  Cultivation  in  the  Philippines. 

The  reports  by  the  Bureau  of  Forestry  in  Mindanao  show 
that  interest  in  rubber  culture  is  increasing  in  that  part  of  the 
archipelago.  Many  seeds  and  seedlings  have  been  planted  during 
the  past  year,  especially  in  the  district  of  Davao,  the  Island  of 
Basilan,  and  along  the  east  and  west  coasts  of  the  Zamboanga 
peninsula.  The  reports  show  the  following  total  number  of  trees 
growing  on  ten  plantations  at  the  present  time  : — Hevea  brasiliensis, 
9,000  ;  Manihof  Glaziovii,  61,000  ;  Castilloa  elastica,  1,000  ; 
total  number,  71,000  ;  or  the  equivalent  of  : — Hevea  rubber,  47 
acres  ;  Ceara  rubber,  313  acres  ;  Castilloa  rubber,  6  acres  ;  total 
366  acres. 

Hevea  Rubber  in  Africa. 

Difficulties  in  connection  with  labour  and  transport  are 
mainly  responsible  for  the  slow  progress  of  rubber  cultivation 
in  Africa.  Bad  selection  in  the  past  appears  to  have  been  a 
frequent  cause  of  failure.  The  soil  and  chmate  conditions 
over  vast  areas  in  the  equatorial  belt  are  quite  favourable  to 
iYiQ^xo-wihoi  Hevea  brasiliensis.  Though  rubber  plants  of  one  kind 
or  another  are  distributed  over  the  southern  parts  of  that  Con- 
tinent, cultivation  is  centred  mainly  on  the  west  coast,  especially 
Sierra  Leone  and  the  Gold  Coast,  in  Central  Africa  (particularly 
the  Congo  and  Uganda)  ;  and  in  East  Africa.  In  the  last-men- 
tioned area  but  little  Hevea  is  grown.  Probably  the  largest 
number  of  trees  of  Hevea  brasiliensis  is  to  be  found  in  the  Congo, 
where  the  growth  has  often  been  reported  to  compare  favourably 
with  that  in  some  of  the  poorer  Eastern  countries.  The  principal 
centre  of  distribution  on  the  West  Coast  has  probably  been  Aburi, 
where  the  Government  Botanic  Gardens  are  established — un- 
fortunately on  a  site  not  of  the  best  for  Hevea  brasiliensis.  The 
demand  for  Hevea  seed  from  Aburi  has  been  great,  and  the 
majority  of  planters  have  had  to  procure  most  of  their  supplies 
direct  from  the  East. 

In  German  Africa  the  only  colony  where  Hevea  appears  to  have 
been  cultivated  is  Cameroon,  seeds  being  introduced  in  1889. 
The  25,000  acres  now  existing  there  consist  one  half  of  Hevea 
and  one  half  of  Funtumia.  Togo  and  German  East  Africa  possess 
Manihot  (Ceara),  but  in  1909  Hevea  brasiliensis  was  not  reported 


40  PARA    RUBBER 

in  either  of  these  colonies.  In  German  East  Africa  there  are  40,000 
acres  of  Ceara,  and  a  small  acreage  under  Castilloa  and  Funturaia. 

In  Angola,  the  principal  cultivated  tree  is  Ceara,  of  which 
there  are  2,000  acres  in  Loanda  district  alone.  Tapping  is  re- 
ported to  be  successful,  which  probably  means  that  a  fair  amount 
of  rubber  is  obtained,  and  not  that  the  tree  suffers  no  harm. 
There  are  also  Mani9oba  trees,  which  are  being  freely  planted  by 
native  owners,  though  they  are  said  to  be  dehcate  and  short-lived. 
Ficus  comes  next  in  favour.  Experiments  with  Castilloa  and 
Funtumia  are  in  progress  on  the  Government's  experimental 
farms.  Experiments  in  growing  "Bitinga"  rubber  have  proved 
a  failure,  as  the  tubers  grow  too  slowly. 

Planting  is  being  carried  out  upon  Fernando  Po,  a  Spanish 
island  in  the  Gulf  of  Guinea. 

The  position  in  the  Congo  Free  State  has  already  been  dealt 
with  in  the  first  chapter. 

Cultivated  Area  under  Rubber  ix  Liberia. 
Mount  Barclay  plantation,  in  Liberia,  has  made  a  promising 
start   in    the   cultivation   of   Hevea   rubber.     According   to    the 
annual  report   of  the   Liberian   Rubber   Corporation,    1910,   the 
estates  contain  the  following  Hevea  trees  : — 


Number. 

Age. 

2,684 

About  3  years  and  5  months. 

4,072 

About  I  year  and  7  months. 

19.327 

About  9I  months  old. 

10,274 

About  8|  months. 

11,623 

Transplanted  from  Nurseries. 

total  47,980    trees — about  241  acres  planted. 

Further  land  has  been  cleared,  and  is  ready  for  planting, 
amounting  to  400  acres,  of  which  about  50  acres  were  recently 
planted  with  Hevea  stumps. 

Possibilities  in  Nigeria. 

A  reasonably  complete  census  of  acreages  and  number  of 
plants  is  not  available  for  Nigeria.  There  are  very  few  large 
plantations,  but  very  many  small  ones  belonging  to  natives. 
Possibly  there  are  more  than  2,000,000  Hevea  and  Funtumia 
trees  planted,  mostly  Funtumia.  The  Government  has  repeatedly 
given  encouragement  to  the  planting  of  rubber  trees,  and  has 
distributed  plants  and  seeds  under  generous  terms  through  the 
Experimental  Stations.  In  Southern  Nigeria  nearly  every 
village  seems  to  have  its  plantation,  and  of  these  there-  appear  to 
be  over  2,000,  containing  many  lianes. 

Gold  Coast  Colony. 

For  obvious  reasons,  it  is  impossible  to  give  complete  statistics 
for  this  area.  Here,  again,  the  Government  is  taking  an  active 
part  in  developing  the  industry,  and  the  natives  have  taken  freely 


PARA     RUBBER  41 

to  it,  but  they  appear  to  have  mostly  planted  Funtumia.  For 
example,  in  1909,  while  only  48,700  Hevea  seedlings  were  dis- 
tributed, the  Funtumia  seeds  numbered  2,274,000.  From 
Coomassie  alone,  in  1910,  there  were  distributed  14,000  Hevea 
seedlings,  and  a  considerable  quantity  of  seeds.  On  the  Gold 
Coast  there  are  a  number  of  larger  undertakings,  and  in  1909  in 
the  Central  Province  some  twelve  iirms  and  individuals  owned 
among  them  106,820  seedlings  and  trees. 

Cultivation    in    Ashanti. 

The  Consular  report  (1907)  for  Ashanti  states  that  the  natives 
were  encouraged  to  cultivate  rubber-yielding  trees,  no  less  than 
seven  thousand  and  eighty  two  plants  {Funtumit  elastica)  being 
distributed  amongst  the  chiefs  of  the  Southern  Province  during 
1907,  most  of  which  are  doing  well.  Twenty-three  acres  of 
Hevea  hrasiliensis,  and  four-and-a-half  acres  of  Funtum  rubber 
[Funtumia  elastica),  were  planted  out  at  distances  of  15  feet  by 
15  feet,  and  10  feet  by  10  feet  respectively,  and  are  doing  well. 
The  agricultural  station  at  Coomassie  distributed  some  12,500 
seedlings  during  1909,  mainly  of  Hevea. 

The  area  under  Hevea  hrasiliensis  at  the  Agricultural  Station 
has  increased  to  55^  acres  ;  and  the  trees,  where  conditions  are 
favourable,  continue,  according  to  the  report,  to  make  rapid 
growth. 

Central  Africa. 

Uganda  has  been  taking  an  active  interest  in  Hevea  cultiva- 
tion. Kaye  reports  (I.R.J.,  March  7th,  1910),  that  at  Entebbe,  the 
seat  of  the  English  Administration,  the  experts  at  the  Botanic 
Gardens  have  given  much  attention  to  experimental  planting. 
The  report  of  the  Botanical  Forestry  and  Scientific  Department, 
Entebbe,  shows  that  good  work  is  being  done  in  distributing  plants 
and  seeds  to  planters  and  chiefs.  Thus  over  a  quarter  million 
Hevea  seeds  were  so  distributed  during  the  year  ending  March 
31st,  1909,  as  well  as  some  thousands  of  Manihot  and  Funtumia 
elastica  seeds. 

Dawe  after  giving,  an  account  of  satisfactory  results  of 
tapping  Hevea  trees  in  Uganda  (I.R.J.,  March  7th,  1910),  states 
that  Hevea  promises  to  grow  satisfactorily.  He  further  reports 
that  ' '  at  the  Nsamba  Mission  Station,  Kampala,  there  is  a  splen- 
didly cultivated  and  extensive  plantation  of  Hevea,  Castilloa,  and 
Ceara,  over  four  years  old.  About  15  miles  from  Kampala  is 
another  thriving  small  plantation,  Kivuvu.  The  soil  is  deep  and 
loamy,  and  the  Hevea  trees  interplanted  with  coffee,  etc.,  are  very 
strong  and  handsome  plants." 

The  Mabira  Forest  Rubber  Company  have  done  extensive 
planting,  and  undoubtedly  hold  the  premier  position  as  rubber 
planters  in  Uganda.  In  the  fertile  areas  of  the  concession  and 
the  wide  open  patches,  thousands  of  Funtumia  elastica  trees  have 
been  planted,  together  with  a  few  hundred  acres  of  Hevea ;  the 
latter  are  reported  to  be  growing  well.     At  Entebbe,  Funtumia 


4i  PARA     RUBBER 

elastica  trees  have  apparently  taken  on  a  bush-like  habit,  but  in 
Mabira  many  of  the  trees  are  growing  tall  and  straight,  as  do  the 
wild  forest  trees  that  are  tappable.  Dawe  is  quite  certain  that 
Hevea  will  be  a  success  in  Uganda  as  a  rubber  yielder,  but  he  is 
not  so  sure  of  the  cultivated  Funtumia  elastica.  This  opinion, 
coming  from  one  who  has  done  such  excellent  work  on  other 
rubber  plants,  will  be  read  with  surprise  by  many  Eastern  planters. 

East  Africa. 
East  Africa  is  not  expected  to  show  any  marked  advance  in 
the  cultivation  of  Hevea  brasiliensis,  though  judging  from  John- 
son's observations  there  appears  to  be  a  possibility  of  profitably 
growing  this  species  under  irrigation.  A  plantation  is  being 
established  under  such  circumstances  on  the  banks  of  the  Buzi 
River,  East  Africa.  Ceara  is,  however,  being  somewhat  extensively 
planted  in  British  and  German  East  Africa. 

Planting  in  Nyassaland. 
It  has  been. conclusively  proved,  says  a  consular  report,  that 
the  Shire  Highlands  are  not  suitable  for  the  cultivation  of  Hevea 
rubber  ;  in  fact  the  only  locality  within  the  Protectorate  where 
this  variety  has  proved  successful  is  in  the  West  Nyassa  District, 
where  600  acres  are  doing  well.  The  rubber  of  Nyassaland  is 
Ceara,  and  the  area  under  this  has  risen  steadily  to  4,500  acres. 
Plantation  rubber  is  now  being  exported. 

Mauritius. 

Rubber  estates  have  been  commenced  in  Mauritius.  Con- 
signments of  seeds  from  Ceylon  have  been  secured  (India-Rubber 
Journal,  June  27th,  1910),  and  planted  at  different  altitudes. 
These  are,  however,  too  young  to  furnish  any  useful  data  as  to  the 
prospects  of  Hevea  in  that  is  and. 

Rubber  in  the  West  Indies. 

Various  consular  reports  and  the  accounts  by  Morris  and 
Hart  give  interesting  details  of  the  history  of  rubber  in  the  West 
Indian  Islands.  It  appears  that  (Hart,  Souvenir,  Indiarubber 
Journal),  about  thirty-seven  years  ago  1here  were  few  trees  of  any 
kind  of  rubber  in  the  West  Indies.  The  oldest  specimens  are 
probably  trees  of  Ficus  elastica  in  Jamaica.  About  that  time 
Hevea  and  other  rubbers  were  sent  from  Kew,  Jamaica  and 
Trinidad  receiving  about  an  equal  share.  In  1887  Hart  found,  in 
Trinidad,  three  trees  of  Hevea  in  the  Botanic  Gardens,  and  several 
scattered  trees  of  other  kinds.  From  1887  onward,  there  was  an 
increasing  demand  for  plants,  Castilloa  in  most  cases  being  pre- 
ferred, as  coming  earher  into  bearing  than  Hevea  and  others,  and 
little  attention  was  paid  to  Hevea.  ' '  In  fact,  it  could  be  hardly 
given  away  until  the  market  prices  went  high,  and  it  then  became 
the  rage,  and  all  the  plants  the  botanical  department  could 
supply  were  eagerly  bought  up  ;     large  numbers  of    seeds  and 


PARA     RUBBER  43 

plants  were  imported,  and  some  good  plantations  have  been 
established.  Funtumia  rubber  was  introduced,  and  a  small 
plot  was  put  out  at  the  Experiment  Station  in  1898.  It  has 
grown  well,  and  has  produced  tall,  thriving  trees.  Manihot  has 
found  but  few  growers,  and  Landolphia  and  other  climbing  rubbers 
are  not  looked  upon  with  favour.  Castilloa  in  Trinidad  stands 
first,  but  considerable  plantations  of  Hevea  and  Funtumia  have 
been  made  in  recent  years. ' ' 

Trinidad  will  probably  prove  favourable  for  the  growth  of 
Hevea  hrasiliensis. 

Rubber  planting  in  Trinidad  and  Tobago  is  in  its  infancy,  and 
owing  to  lack  of  confidence  or  the  necessary  technical  knowledge 
in  cultivation  and  extraction  of  latex,  the  progress  had  not, 
according  to  the  late  J.  B.  Carruthers,  been  very  rapid.  There  are 
at  present  in  Trinidad  rubber  trees  of  ages  varying  from  one  to 
fifteen  years,  but  their  progress  in  growth  has  been  very  slow, 
and  there  are  no  large  trees  anywhere.  The  number  of  trees  on  the 
two  islands  (1910)  has  been  computed  as  follows  : — Castilloa, 
600,000  ;  Hevea,  80,000  ;  Funtumia,  25,000.  Attention  is  now 
being  turned  more  to  Hevea  than  Castilloa. 

Tempany  reports  that  there  are  about  200  acres  of  Hevea  in 
Dominica,  and  that  there  are  prospects  of  a  considerable  extension 
in  the  near  future. 

Jamaica  appears  to  be  quite  unsuitable  for  Hevea,  and  rubber 
planting  has  been  gone  in  for  very  little. 

In  Hayti  it  has  been  given  up. 

In  Grenada  of  recent  years  planting  has  been  taken  up  with 
enthusiasm,  both  Hevea  and  Castilloa,  but  most  of  the  trees 
growing  there  are  less  than  three  years  old.  As  in  other 
West  Indian  islands,  the  total  acreage  cannot  be  large. 

Despite  the  favourable  reports  on  the  growth  of  Hevea  now 
available  from  some  of  the  islands,  it  should  be  borne  in  mind  that 
labour  conditions  are  not  so  favourable  to  the  planting  community 
as  in  other  equally  accessible  areas. 

British  Guiana. 

Hevea  hrasiliensis  and  Sapium  J enmani  are,  according  to 
Harrison,  being  exploited  at  the  Government  experimental 
rubber  stations  in  British  Guiana.  Both  can  be  grown  with 
great  success,  and  a  great  deal  of  valuable  information  has  been 
ascertained  that  will  ensure  more  successful  cultivation  in  the 
future.  It  was  found  that  Sapium  J  enmani  and  Hevea  hrasiliensis 
grew  somewhat  at  the  same  rate,  but  with  regard  to  girth  only, 
Sapium  Jenmani  made  more  rapid  progress.  The  latest  reports  of 
the  tapping  of  Sapium  are  very  discouraging,  from  18  to  33 
ounces,  per  tree,  being  obtained,  in  two  years,  from  trees  varying 
in  girth  from  30  to  92  inches.  It  is  interesting  to  note  that 
there  were,  in  igio,  1,700  acres  under  rubber  cultivation  in  the 
colony  as  against  552  acres  on  the  corresponding  date  of  the  previous 
year,  over  1,000  acres  being  under  Hevea. 


44  PARA     RUBBER 

The  Government  have  recently  endeavoured  to  attract  rubber 
growers  to  British  Guiana  and  have  shown  that  they  are  prepared 
to  lease  lands  for  rubber  cultivation  on  reasonable  terms, 
providing,  among  other  things  : — (i)  During  the  first  ten  years 
of  the  lease  the  lessee  shall  pay  the  sum  of  two  cents  a  pound  for  all 
rubber,  balata,  or  other  substances  of  the  like  nature  obtained  by 
him  from  the  land,  whether  from  indigenous  or  cultivated  trees. 
(2)  The  lessee  shall,  each  year  plant  one  twenty-fifth  part  of  the 
land  leased  with  rubber  trees,  with  an  average  of  not  less  than  60 
rubber  trees  to  each  acre,  until  he  has  so  planted  not  less  than 
ten  twenty-fifth  parts  of  the  said  land  and  shall  maintain  such 
cultivation  in  good  order  to  the  satisfaction  of  the  Govemor-in- 
Council.  (3)  In  clearing  the  said  land  for  cultivation  no  rubber 
tree  or  balata  tree  shall  be  destroyed  without  the  permission  in 
writing  of  the  Commissioner. 

Rubber  in  Dutch  Guiana. 
In  Surinam  the  cultivation  of  rubber  is  exciting  attention. 
There  are  some  165,000  Hevea  trees  growing,  on  36  plantations, 
besides  a  large  number  of  young  plants  at  present  in  the  nurseries. 
Some  800,000  seeds  arrived  from  Ceylon  towards  the  close  of 
1910  ;  in  addition  there  are  a  number  of  Hevea  trees  in  the  colony 
which  are  now  yielding  seeds.  Photographs  of  trees  have  been 
shown  me  which  indicated  that  climatic  and  soil  conditions  were 
favourable  to  the  growth  of  Hevea  brasiliensis  in  parts  of  Surinam. 
There  is  also  the  indigenous  species — Hevea  guyanensis — in  the 
colony  ;  this  yields  less  than  Hevea  brasiliensis  and  the  produce  is 
inferior  in  quality. 

Central  America. 

It  has  been  computed  that  there  are  100,000  acres  of  planta- 
tions in  Central  America  alone,  most  of  which  is  Castilloa.  Some 
Hevea  seeds  have  been  sent  to  British  Honduras,  but  information  is 
not  yet  to  hand  of  their  fate.  The  cultivation  of  Hevea  has  also 
been  started  in  Mexico,  where  the  growth  in  the  nursery  upon  one 
estate  has  encouraged  further  extensions.  About  75  per  cent,  of 
the  first  consignment  of  Ceylon  seeds  germinated.  Central 
America  was  the  leader  in  planting  rubber  if  Brazil  was  not,  for 
it  was  in  1867  that  Don  Jose  Maria  Chacon  planted  Castilloa  at 
Soconusco  in  Mexico,  and  was  followed  during  the  next  year  bv 
others  in  Guatemala,  and  later  in  Nicaragua  and  Honduras.  It  is 
now  clear  that  Central  America  can  never  approach  the  ;\Iiddle 
East  as  a  producer  of  rubber. 

Projected  Rubber  Planting  in  Russia. 
Certain  optimistic  individuals  in  Russia  are  understood  to 
have  under  consideration  a  project  for  planting  rubber  in  the  Black 
Sea  provinces.  We  should  not  be  surprised  to  learn  of  serious 
attempts  being  made  to  cultivate  Ficiis  dastica,  but  even  this 
species  is  hardly  likely  to  compete  successfully  with  the  same 
plant  in  the  Middle  East.     By  the  time  the  trees  come  into  bearing 


PARA     RUBBER  45 

we  imagine  the  price  of  raw  rubber  will  lose  a  good  deal  of  its 
elasticity.     Hevea  rubber  is,  of  course,  out  of  the  question" 

The  World's  Planted  Acreage  in   1912. 

It  is  impossible  to  compile  an  accurate  statement  of  the 
acreages  planted,  in  1912,  throughout  the  world,  but  the  following 
may  be  taken  to  represent  the  approximate  position. 

In  the  Middle  East  Hevea  may  be  taken  as  the  main  cultiva- 
tion ;  elsewhere  Castilloa,  Ficus,  Manihot,  and  Funtumia  are 
planted. 

Of  the  240,000  acres  estimated  in  the  Dutch  East  Indies,  etc., 
only  150,000  acres  are  Hevea  brasiliensis. 

Country.  Acres. 

Malaya     420,000 

Ceylon      . .  .■ 238,000 

Dutch    East    Indies,    Borneo,    and 

Pacific  Islands     240,000 

South  India  and  Burmah 42,000 

German  Colonies     45,000 

Mexico,    Brazil,    Africa,    and    West 

Indies,  etc.  (approximate  only)  100,000 

Total    .....    1,085,000 


An  estimate  by  Van  den  Kerckhove  gives  220,000  acres  to 
Mexico,  80,000  to  Brazil,  and  100,006  to  Africa.  His  total  for 
the  world  is  1,131,000  acres. 

There  are  already  indications  that  Hevea  brasiliensis  will 
outlive  many  other  species,  and  it  may  therefore  be  confidently 
anticipated  that  the  countries  growing  this  plant  will  ultimately 
predominate  as  rubber  producers. 


CHAPTER  III. 

BOTANICAL  SOURCES  OF  RUBBER. 

Knowing  that  the  consumption  of  rubber  is  on  a  sufficiently 
large  scale  to  lead  to  the  investment  of  several  million  sterling 
in  its  exploitation,  it  now  becomes  necessary  to  deal  briefly  with 
the  botanical  sources  of  the  raw  material.  The  most  striking 
feature  of  the  industry  is  the  almost  absolute  dependence  in  the 
past,  and  even  to-day,  of  the  manufacturers  on  rubber  obtained 
from  trees  indigenoiis  to  certain  tropical  forests  and  their  in- 
dependence of  the  plantation  product.  It  is  necessary  to  point 
out  that  tropical  America  is  the  most  important  centre  for  rubber 
collection  (about  60  to  70  per  cent.),  tropical  Africa  the  next 
(20  to  25  per  cent.),  and  tropical  Asia  the  least  important,  since 
it  only  contributes  a  very  small  proportion  (about  10  to  20  per 
cent.),  made  up  of  wild  and  plantation  material.  I  predict,  how- 
ever, that  in  1912  tropical  Asia  will  become  equal  to  tropical 
Africa,  and  will  eventually  overtake  even  tropical  America.  It  is  of 
interest  to  recapitulate  that  the  richest  wild  rubber  areas  in  tropical 
America  (Brazil,  Venezuela,  Bolivia,  Peru,  Central  America,  and 
Mexico),  and  in  tropical  Africa  (Congo  Free  State)  are  not  British, 
though  capital  from  this  country  has  been  recently  diverted  to 
parts  of  these  two  vast  continents  for  the  exploitation  of  rubber. 

Natural  Orders  of  Plants   Yielding  Caoutchouc. 

The  fact  that,  out  of  a  total  annual  rubber  production  of 
75,000  to  90,000  tons,  over  45,000  to  55,000  tons  come  from 
tropical  America,  and  about  22,000  from  tropical  Africa,  compels 
us  to  look  to  these  two  great  continents  for  the  majority  of  the 
caoutchouc-yielding  plants,  and  to  place  the  whole  Asiatic  or  Indo- 
Malayan  region  in  a  minor  or  third  position  of  importance.  Our 
first  duty  is  to  see  which  plants  provide  the  caoutchouc  in  each 
area,  and  to  trace  the  distribution  of  notable  species  from  one 
country  to  another. 

The  natural  order  which  has  furnished,  and  which  still 
supplies  the  greater  part  of  the  world's  rubber,  is  the  Euphor- 
biaceae  ;  the  valuable  species  of  Hevea,  Manihot,  Sapium,  Micrandra 
and  Euphorbia  which  it  comprises  are  indigenous  mainly  to  the 
tropical  American  region,  but  have  been  distributed  to  all  parts 
of  the  tropical  world.  Next  in  importance  is  the  Apocynaceae, 
remarkable  in  tropical  Africa  for  the  valuable  rubber  species  of 
Landolphia,  Funtumia,  Clitandra,  Mascarenhasia,  Carpodinus, 
&c.  ;  this  order  also  comprises  the  genera  Chonemorpha,  Xylina- 
baria,  TabernEemontana,  Melodinus,  Alstonia,  Hancomia,  Urceola, 
Willughbeia,  Hymenelopus,  Parameria,Diplorhynchus,  Forsteronia] 


PARA     RUBBER  47 

Leuconotis,  Ecdysanthera,  and  Micrechites  known  in  many  parts 
of  the  tropics  for  the  quantity  if  not  the  quality  of  rubber  they 
jdeld. 

The  Urticaceae  is  also  of  importance  in  tropical  America  for 
its  species  of  Castilloa,  and  for  the  genera  Ficus  and  Artocarpus 
in  parts  of  Africa  and  the  Indo-Malayan  region. 

The  Asclepiadacese,  though  it  possesses  such  a  large  number 
of  laticiferous  species  abundantly  distributed,  especially  in  tropical 
Africa,  is  remarkable  for  the  absence  of  good  caoutchouc -yielding 
plants;  true,  the  genus  Cryptostegia  in  Madagascar  and  India 
furnishes  us  with  a  small  quantity  of  caoutchouc,  but  .the  other 
important  genera,  such  as  Calotropis,  Cryptolepis,  Marsdenia, 
and  Cyanchum,  have  not  yet  been  found  to  yield  latices  of  high 
commercial  value.  Perhaps  the  most  remarkable  natural  order 
in  this  respect  is  the  Compositae  ;  though  it  is  represented  by  such 
a  large  number  of  species  and  is  to  be  observed  in  almost  every 
part  of  the  temperate  and  tropical  world,  there  are  hardly  any 
species  of  value  to  the  cultivator  of  caoutchouc  plants.  During 
the  last  few  years,  however,  there  is  one  member  of  this  group — 
Parthenium  argentatum,  A.  Gray — which  has  come  to  be  regarded 
as  the  source  of  Guayule  rubber  (8,000  tons  in  1910)  in  Mexico, 
and  another — a  species  of  Hymenoxys — as  the  source  of  Colorado 
rubber.  The  sow-thistle,  Sonchus  oleraceus,  L.,  has  also  been 
mentioned  by  Jumelle  as  5delding  caoutchouc  of  value. 

;,  Another  natural  order  of-  note  in  this  respect  is  the  Lobe- 
liaceae,  since  the  tropical  American  species  of  Siphocampylus, 
found  in  Colombia  and  Ecuador,  have  been  said  to  yield  caoutchouc 
of  commercial  value. 

Geographical  Distribution  of  Caoutchouc  Plants. 

The  geographical  distribution  of  the  more  important  caout- 
chouc-yielding plants  is  imperfectly  known,  but  a  general  idea 
of  the  plant  areas  where  certain  species  thrive  can  be  given. 
/^  Rubber-producing  plants  occur  in  both  hemispheres,  and  are 
'  confined  to  approximately  25  degs.  or  28  degs.  north  and  south 
of  the  Equator/  In  this  area  the  three  most  important  regions  are, 
following  the  floral  regions  of  the  world  as  divided  by  Drude : 
(i)  tropical  American  ;  {2)  tropical  African,  including  Madagascar  ; 
and  (3)  the  Indo-Malayan  region.  These  three  regions  supply 
nearly  the  whole  of  the  rubber  of  commerce.  In  the  first  division 
Brazil  is  the  most  important  indigenous  area,  and  the  West 
Indies  the  most  prominent  for  cultivation  of  introduced  species ; 
in  the  second  division  the  Congo  State  stands  out  prominently  for 
indigenous  and  introduced  species;  in  the  last  division  Malaya 
may  be  taken  as  the  centre  with  the  Dutch  East  Indies  and 
Pacific  Islands  to  the  south,  and  Ceylon  and  South  India  to  the 
'west. 

Indigenous  and  Introduced  Plants. 

It   may:  be  said  that,   of  the  three  areas  enumerated,   the 
tropical  American  and  African  are,  at  present;  mainly  concerned 


48  PARA     RUBBER 

with  the  extraction  of  latex  from,  and  cultivation  of,  plants 
indigenous  to  those  areas — Hevea,Manihot,Funtumia,  Landolphia, 
etc. — whereas  the  Indo-Malayan  region,  though  it  possesses  a  few 
indigenous  species  of  value,  such  as  Ficus  elastica,  Cryptostegta 
grandiflora,  and  others,  is  directing  its  attention,  almost  exclusively 
to-day,  to  the  cultivation  of  species — Hevea  brasiliensis  and 
Manihot  G^aziom— introduced  from  the  tropical  American  region, 
and  to  a  few — notably  Funtumia  elastica — from  the  African  zone. 
The  tropical  American  region  has  been  the  home  of  the  plants  which 
have  led  to  the  rubber  industry  in  Ceylon,  Straits  Settlements, 
Federated  Malay  States,  Dutch  East  Indies,  and  Southern  India, 
and  has  supplied  even  tropical  Africa  with  species  which  rank 
as  of  first  importance  at  the  present  time. 

Trees,  Shrubs  and  Climbers. 

Another  interesting  feature  of  the  laticiferous  flora  of  these 
three  vast  regions  is  the  nature  of  the  plants  predominating  in 
each  area.  It  may  be  said  that  the  caoutchouc  plants  of  the 
tropical  American  area  are  mainly  of  an  arborescent  type, 
e.g.,  Hevea  brasiliensis,  Castilloa  elastica,  Manihot  Glaziovii,  and 
Sapium  ;  a  few  shrubby  plants,  such  as  Parihenium  argentatum, 
and  climbers  such  as  Forsteronia  floribunda,  do,  of  course,  exist 
there. 

On  the  other  hand,  the  rubber  industry  of  the  African. region, 
especially  if  we  include  Madagascar,  is  principally  concerned  with 
lianes,  climbers,  or  root  rubbers, — Landolphia,  Clitandra,  Carpodi- 
nus,  Cryptostegia,  etc.  ;  indigenous  tree  forms,  such  as  Funtumia 
elastica,  Ficus  Vogelii,  Euphorbia  Tirucalli,  and  introduced  tree 
forms  also  abound  in  certain  areas  of  Africa.  In  the  Indo-Malayan 
region,  on  the  other  hand,  there  is  a  mixed  indigenous  flora  com- 
posed of  huge  tree  forms,  such  as  Ficus  elastica,  Dyera  species,  and 
Sapium  insigne  ;  and  chrnbers  such  as  Willughbeia,  Cryptostegia, 
Urceola,  Leuconotis,  Parameria,  etc.,  few  of  which  pay  to  cultivate. 

The  introduced  plants  cultivated  in  the  Indo-Malayan  region 
are  nearly  all  of  the  arborescent  type,  such  as  Hevea,  Manihot, 
Castilloa,  Sapium,  Funtumia,  etc.,  with  a  few  hanes,  the  most 
prominent  of  which  is  Landolphia.  The  table  given  below  will 
show  the  introduced  and  native  plants  now  largely  exploited  for 
rubber  in  the  three  areas  : — 

Important  Caoutchouc  Plants. 

(Generic  Names.) 
I.— Tropical  America  (including  the  West  Indies)  : — 

Native.— Hevea,  Castilloa,  Manihot,  Sapium,  Hancornia, 
Micrandra,  Parthenium,  Hymenoxys,  Brosimum' 
Forsteronia. 

Introduced.— Funtumia,  Landolphia,  Castilloa,  Hevea, 
Manihot. 


PARA     RUBBER  49 

II. — Tropical  Africa  ; — 

Native. — Landolphia,  Funtumia,  Ficus,  Carpodinus,  Clit- 

andra,  Cryptostegia,  Euphorbia. 
Introduced. — Hevea,     Manihot,     Castilloa,      Cryptostegia, 

Ficus. 
III. — Indo-Malay  : — 

Native. — Ficus,    Dyera,   Willughbeia,    Urceola,  Parameria, 

Cryptostegia,  Chonemorpha,  Ecdysanthera,  Leu- 

conotis,  Rhynchodia. 
Introduced. — Hevea,       Manihot,       Castilloa,       Funtumia, 

Landolphia. 

Rubber-Yielding  Species. 

Most  companies  engaged  in  rubber  cultivation  have  selected 
trees  for  planting  purposes  which  have  become  known  in  virtue  of 
their  caoutchouc-yielding  capacities.  It  is  as  well  to  state  that  in 
each  of  the  genera  Hevea,  Castilloa,  Manihot,  Ficus,  etc.,  as  in 
many  others,  there  are  numerous  species  known  to  yield  caoutchouc, 
but  in  very  variable  quantities  and  of  different  qualities. 
Undoubtedly,  in  tropical  America  and  Africa,  the  latices 
of  numerous  species  frequently  contribute  to  the  rubber 
exported  in  a  form  known  under  only  one  name,  and  the 
real  rubber  values  of  many  species  of  Hevea,  Sapium, 
Euphorbia,  Dyera,  Landolphia,  and  Manihot,  are  but 
little  known,  except  to  the  natives  on  the  spot.  This  has 
been  dealt  with,  in  detail,  in  the  first  chapter.  There  are  some 
companies  operating  in  tropical  America  who  find  it  to  their 
interest  to  cultivate  species  of  Manihot  other  than  M.  Glaziovii, 
though  the  latter  is  the  species  of  Manihot  which  was  first  sent 
to  the  East,  and  which  everyone  has  hitherto  associated  with 
Ceara  rubber  for  many  years.  The  results  obtained  with  species 
of  Manihot  in  Malaya  are  far  less  favourable  than  those  reported 
in  East  Africa  where  the  climate  is  much  drier  and  hotter. 

Laticiferous    and    Caoutchouc    Plants. 

/It  is  necessary  to  explain  that  numerous  plants  possess  latex 
large  quantities,  but  the  viscous  liquid  is  often  almost  useless 
on  account  of  the  low  percentage  of  caoutchouc  or  the  high  per- 
centages of  albuminous,  resinous,  and  other  substances  present./ 
Everyone  must  have  noticed  the  milky  liquid  which  issues  from 
the  cut  surfaces  of  Sonchus  arvensis  and  species  of  Euphorbia — 
plants  which  occur  abundantly  in  parts  of  Europe.  In  the  tropics 
there  are  many  trees,  such  as  species  of  Carissa  and  Plumeria, 
Euphorbia  TirucalU  and  aniiquorum  ;  climbers  or  lianes,  notably 
Cryptostegia  grandiflora,  and  Willughbeia  zeylanica,  which  almost 
squirt  out  large  quantities  of  latex  when  cut  with  a  knife.  The 
same  may  be  said  of  Palaquium  and  Bassia  in  Ceylon — genera 
from  which  the  guttapercha  of  commerce  is  obtained,  but  which 
in  the  island  mentioned  yield  latex  in  small  quantities  and  of  very 
little  commercial  value.      Pontianak,  a  resinous  rubber  obtained 


50  ,  PARA     RUBBER 

from  Dyera  trees  is,  after  chemical  treatment,  now  shipped  as 
ordinary  crepe  rubber  and  competes  favourably  with  plantation 
Para  ;  this  illustrates  the  possibihties  with  other  trees  now  yieldmg 
inferior  rubbers.  The  latices  of  importance  usually  possess  high 
percentages  of  caoutchouc — the  compound  which  largely  deterrnines 
the  uses  to  which  the  dried  product  can  be  put.  If  one  considers 
species  of  the  same  genus,  the  striking  fact  is  revealed  that  the 
chemical  composition  of  the  latex  is  almost  of  specific  importance. 
There  are  many  species  of  Hevea,  Landolphia,  Ficus  and  Funtumia, 
but  only  certain  members  possess  high  percentages  of  caoutchouc 
and  low  percentages  of  resins  and  proteins. 

The  high  percentage  of  rubber  in  the  latex  from  Hevea 
brasiliensis  and  the  adaptability  of  plants  of  this  species  have, 
together  with  other  factors,  led  to  this  species  being  selected  in 
most  Eastern  countries  for  cultivation.  It  is,  therefore,  necessary 
to  deal  somewhat  fully  with  the  important  botanical  character- 
istics of  this  particular  plant. 

Botanical    Characters    of    Hevea   Brasiliensis. 

M.  H.  Jumelle  (Les  Plantes  a  Caoutchouc  et  a  Gutta,  by 
Henri  Jumelle,  Paris,  1903)  devotes  considerable  attention  to 
the  supposed  varieties  of  Hevea  brasiliensis,  and,  like  many  other 
botanists,  concludes  that  the  differences  in  colour,  size,  and  shape 
of  the  leaves  described  by  Ule  and  others  are  not  constant  and 
may  be  disregarded.  The  leaves  are  trifid,  long,  and  lanceolate, 
each  on  a  long  petiole. 

The  flowers  are  monoecious,  and  are  grouped,  at  the  tips  of 
branches,  in  panicles  of  small  cymes  ;  each  inflorescence  has  two 
kinds  of  flowers,  male  and  female,  which  permits  of  artificial 
pollination  without  much  difficulty  should  plant  selection  be 
adopted  in  the  future.  The  calyx  is  usually  five-lobed  ;  the 
stamens  of  the  male  flowers  are  united  in  the  centre  to  form  a 
column  ;  the  female  flowers  usually  possess  five  staminodes,  a 
small  3-celled  ovary,  and  3  ,  sessile  or  short-styled  stigmas  ;  the 
fruit  is  a  three-lobed  capsule,  in  which  the  three  oval  oleaginous 
seeds  are  contained.  The  seeds  are  each  about  the  size  of  a  nutmeg, 
and  shiny  and  speckled  brown  on  the  surface  ;  they  are  often 
scattered  a  distance  of  50  feet  when  the  fruits  burst  with  a  loud 
report. 

There  are  about  twenty  species  of  Hevea  recognized  by 
Mtiller,  Hemsley,  and  Huber. 

Botanically  the  genus  Hevea  has  been  divided  by  Huber 
("Essaio  d'uma  Synopse  das  Especies  do  Genero  Hevea  sobos 
pohtos  de  vista  Systematico  e  Geographico ")  into  two  sections, 
each  of  which  is  subdivided  into  series.  Hevea  brasiliensis  belongs 
to  section  Bjsiphonia,  Muell.  Arg.,  and  series  Intermediae,  and  is 
-characterised  by  having  anthers  in  two  complete  series,  in- 
florescence pale-yellow  or  white,  buds  of  the  male  flowers  acuminate 
and  obsolete  styles. 


Photo  hy  P.  H.  Macmillan. 


LEAVES,        FLOWERS,        FRUITS,      AND      SEEDS       OF      HEVEA 
BRASILIENSIS. 


LV 


Siu'i-iaUii  dfaini  hi/  B.  J.  Tabor. 

A.  TRANSVERSh     SECTION      THROUGH      BARK      OF      OLD     STEM  ; 

BARK     8mm.     THICK. 

B.  TRANSVERSE     SECTION     THROUGH     SECONDARY      PHLOEM. 

C.  TANGENTIAL     SECTION     OF      INNER     CORTEX. 

S.C.    stone   cells.       T.L.V.   Tangential  bands   of  laticiferous  vessels.    M.B. 
Medullary    rays.     C.    Companion    cells.    S.    Sieve    tubes.    L.V.    Laticiferous 

vessels, 

1.   Cork.    2.   Cortex.       3.    Phloem   or  inner   cortex,    i.  Cambium.    5.  Wood. 


PARA     RUBBER  51 

Species  of  Hevea  and  their  Distribution. 

The  genus  Hevea  furnishes  the  largest  quantity,  and  perhaps 
the  best  quaUty,  of  rubber  in  the  world  ;  some  samples  of  carefully 
prepared  Lagos  lump  from  Funtumia  elastica  and  Ceara  from 
Manihot  Glaziovii  are  said  to  be  equal,  in  many  respects,  to  the 
finest  Para.  It  is  represented  by  Hevea  hrasiliensis,  Muell.  Arg., 
and  H.  similis,  Hemsl.,  in  Brazil,  Eastern  Peru,  and  Bolivia  ;  by 
H.  spruceana,  Muell.  Arg.,  H.  minor,  Hemsl.,  H.  benthamiana, 
Muell.  Arg.,  H.  rigidifolia,  Muell.  Arg.,  and  H.  discolor  in  North 
Brazil ;  by  H.  pauciflora,  Muell.  Arg.,  in  North  Brazil  and  British 
Guiana  ;  by  H.  lutea,  Muell.  Arg.,  in  North  Brazil  and  East  Peru  ; 
by  H.  confusa  in  British  Guiana,  and  by  H.  guyanensis,  Aub.  In 
the  basin  of  the  Amazon  and  in  the  south  of  Venezuela  and  the 
Guianas,  species  of  Hevea  are  abundant  and  scattered  among 
other  forest  types  ;  further  north  they  are  replaced  by  Castilloa 
and  Parthenium,  and  on  the  Atlantic  side  by  Manihot  and 
Hancornia. 

Hevea  hrasiliensis  is,  in  the  wild  state,  distributed  through 
the  southern  part  of  the  Amazon  basin.  It  occurs  on  the  low 
alluvial  lands  of  the  affluents  of  the  great  river  and  also  on  the 
high  lands.  Huber  states  that  this  species  is  specially  abundant 
(i)  on  tide-flooded  islands  and  the  mouth  of  the  Amazon,  in- 
cluding the  lower  courses  of  the  rivers  Tocantins  and  Xingu,  (2) 
the  middle  course  of  the  rivers  Xingu  and  Tapajoz,  (3)  the  Brazilian 
part  of  the  basin  of  the  river  Madeira  and  its  affluents,  (4)  the 
Acre  Territory,  together  with  the  upper  basin  of  the  Rio  Madeira 
belonging  to  Brazil  and  Bolivia,  and  (5)  the  valleys  of  the  rivers. 
Purus,  Yurua,  Yutahy,  Yavary,  and  the  lower  valley  of  the 
Ucayali.  The  Acre  Territory  is  described  as  one  of  the  richest 
rubber  countries  in  the  whole  of  tropical  America,  and  the  con- 
struction of  the  Madeira-Mamore  railway  is  expected  to  lead  to  a 
material  increase  in  the  output  of  rubber  from  that  part  of  South 
America. 

Commercial    Value    of    Hevea    Species, 

Huber  recognises,  in  a  commercial  sense,  several  groups  of 
Hevea  species,  and  has  given  to  many  species  new  names.  He 
regards  Hevea  hrasiliensis  and  Hevea  henthamiana  as  the  two 
species  yielding  the  highest  class  of  rubber,  H.  henthamiana  being 
for  the  northern  affluents  of  the  Amazon  what  H.  hrasiliensis  is 
for  the  main  river  and  its  southern  affluents  ;  collectors  are  said 
to  regard  the  former  as  a  variety  of  the  latter.  In  the  second 
group  he  places  H.  guyanensis,  H.  collina,  H.  nigra,  H.  cuneata, 
H.  lutea  and  H.  paludosa  ;  these  yield  ' '  borracha  fraca ' '  or  weak 
rubber.  These  species  do  not  generally  grow  together  in  the  same 
localities,  only  H.  guyanensis  being  found  mixed  with  H.  hrasiliensis, 
and  the  latices  ^fe  theriefore  not  likely  to  become  mixed  with  that 
of  the  premier  species.  In  the  third  group  H.  spruceaHa,  H.  discolor, 
H.  similis,  and  H.  viridis  are  placed  ;  these  yield  only  small 
quantities  of  latex  which  give  a  sticky,  weak  rubber.  - 


52  PARA     RUBBER 

Among  the  species  of  Hevea  enumerated  above  there  are 
several  which  shield  large  quantities  of  latex,  but  Hevea  brasiliensis 
is  probably  responsible  for  the  greater  part  of  the  Para  rubber 
of  commerce.  H.  benthamiana  has  been  confused  with  Hevea 
brasiliensis,  and  is  said  to  be  cultivated,  at  the  present  time, 
in  some  parts  of  Venezuela. 

H.  discolor  has  lately  received  considerable  attention,  and 
though  its  latex  is  said  to  be  used  for  adulterating  purposes,  it 
does  not  appear  to  possess  very  much  caoutchouc. 

The  names  of  common  grades  of  rubber  obtained  from  various 
species  of  Hevea  are  given  in  the  first  chapter,  and  should  be 
studied  in  connection  with  the  above  details  of  distribution. 
Steglich  Von  Hassel  beheves  that  in  the  upper  Amazon  there 
are  600  kinds  (varieties  ?)  of  caoutchouc  trees. 

According  to  Sperber  (Tropenpflanzer,  Feb.,  1910)  the  follow- 
ing species  are  tapped  in  Peru: — Hevea guayensis  (?),  which  attains 
a  height  of  15  to  20  metres,  and  a  diameter  of  60  to  80  cm.  ; 
H.  brasiliensis,  height  18  to  20  metres,  and  diameter  60  to  80 
cm.  ;  H.  audinensis  (?),  height  15  to  20  metres,  and  diameter 
70  to  80  cm.  ;  H.  lutea,  height  18  to  20  metres,  and  diameter 
50  to  60  cm. 

Foliar   Periodicity   of   Hevea   Brasiliensis. 

Trees  of  Hevea  brasiliensis  exhibit  marked  foliar  periodicities 
in  the  East.  During  the  first  two  or  three  years  the  young  tree 
may  retain  its  leaves  and  show  a  nett  increase  in  foliage  at  regular 
intervals.  After  the  third  or  fourth  year,  however,  the  tree 
annually  drops  its  leaves,  but  quickly  puts  on  a  fresh  supply  of 
young  foliage.  When  growing  under  healthy  conditions  the 
trees  in  Ceylon  and  Malaya  usually  change  their  leaves  from 
January  to  March  ;  in  badly-drained  places  the  foliar  change  is 
very  irregular.  The  tapping  operations  are  believed,  by  many 
persons,  to  change  to  a  varying  degree  the  periodicity  of  leaf-faU 
and  production. 

The  following  observations  apply  to  some  of  the  oldest  trees 
at  Peradeniya  and  Henaratgoda  : — 

Number  of 

Number  of  Tree  New  Leaves  Days 

AND  Year.                 Leaf-Fall.                 Appeared.  Trees  Leafless. 
Commenced.     Finished. 

I.  1901-2      ..   November.      Jan.  6th.          Feb.  2nd.  26  days. 

II.  1902          .  .    Jan.  1st.          Feb.  23rd.       Feb.  28th.  4 
1903         .  .   Jan.  3rd.          Feb.  26th.       March  2nd.  3     "    , 

III.  1903          . .   Sept.  29th.      November.      November.  — 

IV.  1902         ..   Jan.  4th.          Jan.  14th.        Jan.  24th.  9  days. 
1903         ..   Jan.  2ist.        Feb.  3rd.         Feb.  loth.  6 

In  its  native  home  the  tree  is  said  to  become  leafless  between 
March  and  July  ;  but  in  parts  of  Peru  it  passes  through  this  phase, 
according  to  Sperber  (Tropenpflanzer,  Feb.,  1910),  from  July  to 
September. 


PARA    RUBBER  53 

Fruit  Pekiodicity  in  Singapore. 

There  is  a  considerable  difference  between  the  trees  in  the 
Singapore  Botanic  Gardens  and  the  average  mature  trees  in  Ceylon. 
In  the  Straits,  according  to  Ridley,  the  trees  may  bear  fruit  in  any 
month  of  the  year,  although  the  period  of  heaviest  seed  crop  is 
July-October  with  another  heavy  crop  in  the  month  of  March. 
The  following  table  shows  the  total  number  of  seeds  collected 
in  each  month  for  nine  consecutive  years  in  the  Singapore  Gar- 
dens : — 


January 

February 

March 

April 

May 


32,924  July  . .  29,650 

55,800  August  . .  79,600 

148,050  September  . .  324,515 

56,314  October  .  .  291,436 

28,097  November  . .  85,870 

28,700  December  . .  35,807 


Ridley  concludes  (a)  that  while  there  are  two  seasons  when 
flowers  and  fruits  may  occur  in  some  years  within  the  period  of  a 
year,  there  is  never  more  than  one  heavy  crop  annually  ;  (b)  that 
the  autumn  crop  is  the  more  uniform  of  the  two,  as  the  spring  has 
only  exceeded  the  autumn  crop  twice  in  10  years  ;  and  (c)  that  the 
autumn  fruit  periodicity  represents  the  true  normal  condition  of 
the  tree. 

Fruit  Periodicity  in  Ceylon. 

The  fruit  periodicity  in  Singapore  agrees  more  or  less  with 
Ceylon,  where  there  is  a  main  or  only  fruiting  period  in  the  autumn. 
(The  Uva  province  is  the  only  district  in  Ceylon  where  there  is  a 
special  spring  fruit  period,  February- April) .  The  best  crop  month 
in  spring  is  March,  which  over  a  period  of  nine  years  stands  third 
in  the  annual  returns,  and  varies  from  nil  return  in  1905,  and  only 
50  seeds  in  1902,  to  43,050  seeds  in  1901.  A  similar  variation  may 
be  observed  in  the  autumn  crop  for  August,  which  out  of  a  total 
of  79,600  seeds  for  9  completed  years  produced  no  less  than  60,850 
seeds  during  that  month  in  1905. 

In  the  south  of  Ceylon  the  principal  seed  crop  is  in  the 
autumn,  collecting  extending  from  August  to  November. 

On  the  Gold  Coast  the  fruiting  season  is  from  July  to  October. 

In  Brazil,  according  to  Temple,  the  fruits  begin  to  fall  in  March, 
and  according  to  Witte,  about  December  and  January ;  the 
latter  states  that  the  trees  sometimes  blossom  twice  a  year. 

/Laticiferous  Systems  of  Plants. 
All  the  species  which  yield  rubber  are  characterised  by 
systems  of  sacs,  series  of  cells,  or  tubes  containing  latex  ;  these 
occur  in  nearly  all  parts  of  the  plant./The  commercial  possi- 
bilities and  the  ultimate  success  of  several  species  are  determined 
by  the  particular  type  of  laticiferous  tissue  which  each  contains. 
When  one  considers  the  great  difference  in  the  nature,  mode  of 
origin,  and  development  of  the  laticifers  in  various  plants,  there  is 
every  reason  for  suggesting  that  each  species  should  be  tapped 


54  PARA    RUBBER 

on  a  particular  system  in  order  to  take  advantage  of  the  pecu- 
liarities of  each  type. 

From  a  study  of  the  laticiferous  system  of  our  prominent 
plants,  I  am  convinced  that  in  certain  instances  the  old  native  and 
apparently  wasteful  methods  adopted  in  the  extraction  of  latex 
are  probably  as  good  as,  and  even  better  than,  many  which  have 
been  evolved  by  Europeans. 

The  laticiferous  system  in  several  of  our  important  species 
occurs  in  the  cortex  of  the  stem,  branches,  roots,  and  in  the 
leaves,  flowers,  and  fruits.  In  some  species,  the  laticifers  appear 
to  be  best  developed  in  the  root  and  the  extraction  of  latex  is  only 
considered  in  relation  to  that  part  ;  in  other  species  there  appears 
to  be  a  better  development  in  the  stem,  and  in  a  few  others  the 
flowers  or  young  twigs  show  conspicuous  developments.  Gen- 
erally, the  laticifers  and  the  latex  appear  in  the  embryo  and 
remain  until  the  death  of  the  plant  ;  in  some  cases,  however, 
the  laticifers  are  not  obvious  except  in  plants  of  some  years' 
growth.  Sometimes  they  are  absolutely  restricted  to  stems  and 
roots,  the  leaves  and  flowers  never  being  in  possession  of  such 
structures  ;  in  a  few  cases  they  appear  in  the  young  tissues,  and 
then  gradually  die  and  disappear. 

It  will  perhaps  be  sufficient  to  state  that  there  are  three  types 
of  laticiferous  systems  the  components  of  which  are  scattered 
freely  throughout  the  cortex  in  the  stem  ;  they  may,  according  to 
their  age  and  the  condition  of  the  plant,  be  partially  or  wholly 
filled  with  latex. 

Stem  Structure  of  Hevea  Brasiliensis. 

On  plantations  the  part  of  the  plant  which  is  most  affected  is 
the  stem,  this  being  subject  often  to  daily  or  alternate  day  tapping 
until  the  whole  of  the  so-called  ' '  bark ' '  on  the  lower  part  of  the 
trunk  has  been  removed.  The  practical  man  knows  that  he  has 
to  avoid  cutting  too  deeply  during  tapping,  and  usually  the  only 
indication  of  having  done  this  is  exposure  of  wood.  It  is,  therefore, 
advisable  to  give  a  brief  description  of  the  stem  tissues  excised 
in  the  principal  operation  on  the  estate. 

Bark. 

Commencing  on  the  outside,  we  have  a  dark-coloured,  dry 
bark  ;  this  isformed  by  the  drying-up  of  the  outer  soft  cells  of  the 
living  cortex  in  young  saplings  and  older  plants,  but  later  on  in 
life  is  largely  produced  by  series  of  cells  (bark-cambium)  that 
continually  divide  and  form  bark  cells  on  the  outside  and  other 
living  cells  internally.  The  bark  represents  tissue  which  has 
lost  all  its  reserve  food  supplies,  and  is  always  peeling  off ;  it 
can,  therefore,  be  dispensed  with  as  being  of  Httle  importance  to 
the  planter. 

Cortex. 
Inside  the  bark  there  is  a  collection  of  soft  hving  cells,  which 
form  a  thick  layer  extending  from  the  dry  bark  nearly  to  the 


PARA     RUBBER  55 

wood  ;  this  is  the  ' '  cortex, ' '  and  constitutes  the  greater  part  of  the 
so-called  "bark"  which  is  cut  away  during  tapping  operations. 
It  is  this  layer  which  contains  abundance  of  reserve  food,  and 
which  not  only  serves  as  a  store-house,  but  as  the  main  channel 
along  which  food,  elaborated  in  the  leaves,  is  conducted  from 
above  downwards.  If  this  layer  is  removed  entirely  around  the 
stem  at  one  level,  the  cut  edge  on  the  lower  part  of  the  stem  will 
become  thin  and  dry  ;  the  upper  part,  still  in  connection  with  the 
cortex  and  therefore  the  foliage  above,  begins  to  bulge  out,  pro- 
bably because  the  food  materials,  being  stopped,  have  accu- 
mulated there  in  their  downward  course.  The  wound  area  will 
always  heal  from  above  downwards — this  indicates  the  one 
important  function  of  conducting  elaborated  food  materials  in 
this  direction  executed  by  the  cortex.  This  thick  layer  of  living 
cells  also  contains  the  laticifers  in  which  the  latex  accumulates. 
The  latex  channels  are  less  crowded,  but  larger,  in  the  outer  than 
the  inner  layer  of  cortex.  In  tapping  it  is  this  thick  cortex,  and 
the  thin  layer  of  dry  bark,  which  is  removed.  It  is,  therefore, 
clear  that  this  tissue,  containing  food  for  the  plant  and  the  special 
structures  filled  with  latex,  is  of  the  greatest  importance,  not 
merely  now  to  the  planter,  but  to  the  future  life  of  the  tree.  It 
should  be  preserved  as  long  as  possible.  Above  all,  the  means 
whereby  it  is  continuously  produced  should  be  protected. 

Cambium. 

This  brings  us  to  the  important  part  known  as  the  cambium — 
the  layer  of  cells  which,  so  long  as  it  is  not  injured,  produces 
cortical  cells  externally  (wherein  new  laticifers  appear  and  food 
supplies  accumulate)  ,^  and  wood  internally.  This  layer  is  not 
concerned  with  storing  food  ;  it  does  not  contain  latex  ;  it  does 
not  perform  any  function  of  importance  beyond  that  of  dividing 
to  produce  cortical  and  wood  cells  on  opposite  sides.  If,  in 
tapping,  this  layer  is  injured,  the  healing  and  growing  capacity 
of  the  tree  is  affected,  and  the  production  of  new  cortical  cells, 
on  which  renewed  tapping  depends,  is  checked.  It  is  an  ex- 
tremely thin  layer,  probably  not  thicker  than  the  sharp  cutting 
edge  of  the  tapping  knife,  and  is  the  dividing  line  between  the 
cortex  and  wood. 

Wood. 

Within  the  cambium  is  the  wood,  detected  immediately  by 
its  hard  texture  and  lighter  colour  whenever  the  tapper  has  gone 
below  the  healing  or  cambium  layer.  The  wood  is  a  part  of  the 
tree  which  should  have  no  claim  on  the  planter's  mind,  and  will 
therefore  not  be  described. 

Laticiferous    System    of    Hevea    Brasiliensis. 

In  Hevea  brasiliensis  the  latex  is  contained  in  definite  ducts 
which  occur  throughout  the  stems,  roots,  leaves,  flowers,  and 
fruits.  The  laticiferous  ducts  in  Hevea  brasiliensis  begin  as  a 
series  of  cells,  the  walls  of  which  break  down  and  thus  give  rise  to 


56  PARA    RUBBER 

the  formation  of  a  number  of  tubes,  disposed  more  or  less  longi- 
tudinally. In  some  cases  the  walls  of  the  cells  are  only  incom- 
pletely disintegrated,  and  the  flow  of  the  latex  is,  therefore,  not 
as  free  as  when  the  partition  walls  are  completely  broken  down. 
The  disconnected  series  of  cells  in  all  stages  of  perforation  is 
accountable  for  many  of  the  variations  in  jaeld  of  latex  and  rubber 
described  elsewhere. 

Scott,  in  his  paper  (Linn.  Soc.  1885)  on  the  occurrence  of 
articulated  laticiferous  vessels  in  Hevea,  states  that  the  embryo  of 
Hevea  hrasiliensis  contains  well-developed  laticifers,  which  form  a 
complex  anastomosing  system  ;  numerous  and  extensive  per- 
forations occur  in  the  lateral  walls,  though  the  absorption  of  the 
transverse  walls  may  not  be  complete.  Scott  believed  that  the 
perforation  of  the  lateral  walls  commenced  at  an  earher  stage  than 
that  of  the  transverse  walls.  In  many  parts  of  his  paper  he  points 
out  that  remnants  of  the  transverse  walls  remain  though  large 
numbers  of  cells  have  undergone  fusion.  The  same  processes  of 
perforation  and  disappearance  of  cell  walls  go  on  in  the  secondary 
cortex,  and  the  laticiferous  system  is,  though  communicative  to 
some  degree,  relatively  disconnected,  compared  with  the  straight, 
open,  non-articulated  tubes  in  certain  Castilloa  and  Euphorbia 
species. 

Chimani  found  that  in  a  twig  of  diameter  8'5  mm.  (^in.), 
the  latex  tubes  had  a  diameter  of  from  yJ^jo  in.  to  y^'^^^in. 

How    Latex    Channels    are    Formed. 

An  examination  under  a  high  power  of  the  microscope  reveals 
how  the  latex  tubes  arise  and  become  filled  with  the  globules  of 
the  different  substances  which  ultimately  give  the  rubber  of 
commerce,  for  here  and  there  can  be  seen  the  breaking-down  of 
the  regular  cells  and  the  production  of  a  single  irregular  tube 
by  the  disappearance  of  partition  walls.  This  decomposition, 
essential  for  the  production  of  the  latex  tubes  in  Hevea  and 
Manihot  rubber  trees,  commences  in  the  germinating  seeds  and 
continues  until  death  ;  even  when  the  trees  are  to  all  appearances 
dead,  they  may,  three  years  after  throwing  out  their  last  leaf,  still 
maintain  the  latex  tubes  and  yield  latex  of  fair  quality.  What  are 
perfectly  normal  and  regular  cells  in  the  bark  to-day  may  begin 
to  show  perforations  to-morrow,  and  within  a  few  days  or  a  week 
a  system  of  latex  tubes  may  arise  in  an  area  which,  had  it  been 
tapped  too  early,  would  never  have  yielded  a  drop  of  latex.  The 
formation  of  latex  tubes  from  a  series  of  single  cells  may  be 
illustrated  by  knocking  out  the  cross-walls  of  an  ordinary  bamboo  : 
from  a  series  of  separate  chambers  a  single  tube  with  the  remnants 
of  the  cross-walls  may  be  obtained.  It  should  be' clearly  under- 
stood that  the  latex  tubes  of  Hevea  trees  arise  by  the  perforation 
and  decomposition  of  ordinary  cells  of  the  cortex  ;  secondly,  that 
the  processes  involved  require  an  interval  of  time  for  their  com- 
pletion which  the  constitution  of  the  plant  determines  ;  and  lastly 
that  in  tapping  operations  we  are  deahng  with  a  series  of  channels 
which  have  no  very  vital  association  with  other  parts  of  the  cortex. 


PARA     RUBBER  57 

The  formation  of  new  laticifers  cannot  be  pre-determined 
by  microscopical  examination  of  the  newly-formed  cortical  cells, 
the  disappearance  of  the  transverse  walls  taking  place  irregularly 
in  the  cortex  ;  though  Ceylon  criticisms  suggested  otherwise,  the 
origin  de  novo  in  the  secondary  bark  is  accepted  by  microscopists. 
In  a  general  way  it  may  be  stated  that  the  longer  the  cortex  is 
allowed  to  remain  on  the  tree  the  greater  the  number  of  cell 
fusions  effected  ;  the  greater  the  number  of  cortical  cells  available 
the  larger  the  number  of  laticifers,  within  limits,  which  are  likely 
to  be  formed.  The  laticiferous  system  in  Hevea  hrasiliensis  does 
not  increase  in  size  by  prolongation  of  original  sacs  as  in  many 
other  plants,  but  by  the  disappearance  of  cell  walls  ;  such  a  system 
is,  despite  statements  implying  the  contrary,  relatively  discon- 
nected (compared  with  the  Castilloa  or  Euphorbia  type),  though 
there  is,  as  every  one  knows,  communication  of  some  kind  between 
the  disintegrated  cells  in  each  area.  In  Hevea  hrasiliensis  parts 
of  cross  walls  may  remain,  whereas  in  the  non-articulated  types 
these  never  exist.  The  laticifers  in  Hevea  rubber  trees  have  been 
called  "vessels,"  "sacs,"  "tubes,"  etc.,  but  the  name  is  of  no 
great  practical  importance,  and  can  only  confuse  the  point  at  issue 
The  term  ' '  fused  cells ' '  would  probably  convey  the  most  correct 
idea  for  the  laticifers  in  Hevea  hrasiliensis,  as  against  the  word 
' '  tubes ' '  for  those  in  Castilloa,  and  the  term  ' '  sacs ' '  for  those  in 
certain  guttapercha-yielding  plants. 

Formation  of  Rubber  in  Situ. 

No  one  has  yet  determined  the  total  quantity  of  rubber 
procurable  from  the  whole  of  the  bark  of  a  Hevea  rubber  tree  of 
known  age  or  size  by  felling  the  tree  and  macerating  the  milky 
tissues.  But  it  is  well  known  that,  irregularly  connected  though 
the  laticifers  in  this  species  may  be,  the  quantity  of  rubber  pro- 
curable by  tapping  may  greatly  exceed  the  actual  weight  of  bark 
removed  even  when  a  wasteful  excision  method  is  adopted.  It  is 
therefore  obvious  that  the  rubber  must  be  formed  in  the  bark 
in  virtue  of  the  associations  of  the  laticifers  with  other  parts  of  the 
plant  which  permit  the  circulation  of  ingredients  ultimately 
forming  part  of  the  latex.  The  laticifers  in  the  bark  are  usually 
surrounded  by  cells  which  either  store  food  supplies  or  conduct 
the  sap  elaborated  in  the  leaves  from  above  downwards  ;  their 
walls  are  very  thin  and  the  permeation  of  solutions  from  the 
surrounding  cells  is  easily  accomplished. 

Whenever  laticifers  are  cut  it  is  obvious  that  they  must 
partially  drain  those  with  which  they  are  connected  and,  after 
closing,  again  become  partly  filled  with  the  latex  from  connected 
laticifers.  At  the  same  time  certain  cortical  cells,  which  have 
been  cut  off  from  the  cambium  in  the  usual  manner,  are  gradually 
converted  into  laticifers  which  themselves  become  charged  with 
latex.  It  is  impossible  when  examining  young  cambium  products 
to  distinguish  which  cortical  cells  will  form  laticifers  in  the 
secondary  cortex. 


58  PARA    RUBBER 

In  order  to  determine  whether  caoutchouc  is  developed  at 
the  place  where  it  is  collected  from  the  tree,  experiments  were 
being  made  (Tropical  Agriculturist,  September,  1907)  in  Ceylon  : 
"trees  are  being  ringed,  and  half-ringed,  at  distances  of  a  foot,  and 
all  the  milk  removed,  to  determine  whether  new  rubber  is  formed 
between  the  rings."  The  results  of  these  experiments  will  be 
awaited  with  interest.  In  April',  1908,  the  isolated  cyhnders  of  bark 
possessed  a  fair  quantity  of  latex. 

Variability  of  Laticiferous  System  in  Hevea. 
Considerable  variation,  suggestive  of  internal  differences, 
has  already  been  recorded  in  the  yield  of  latex  from  tapped 
trees  in  the  East.  Variations  in  the  nature  and  yield  of  latex 
from  trees  at  all  elevations  are  to  be  expected  for  one  simple 
reason  :  the  laticiferous  system,  from  which  the  latex  is  obtained, 
is  not  a  vital  part  of  the  tree.  There  is,  of  course,  a  general 
anatomical  constancy,  and  the  majority  of  the  trees  of  Hevea 
brasiliensis  possess  latex  throughout  their  lives  ;  but  in  some 
cases  the  trees  do  not  yield  normal  latex  during  certain  periods, 
though  subsequently  they  contain  this  mixture  in  large  quantities. 
Generally  speaking,  one  may  say  that  there  is  less  constancy"  in 
parts  of  the  plant  which  are  not  of  vital  importance  than  in  those 
upon  which  the  cohtinuity  of  the  tree's  life  depends  ;  for  instance, 
the  peculiar  cells  which  are  of  vital  importance  and  conduct  and 
store  food  materials  from  the  leaves — phloem  tubes  and  companion 
cells — are  much  more  constant  in  the  cortex  of  Hevea  brasiliensis 
than  are  the  non-vital  latex  tubes.  There  is  no  need  to  get 
alarmed  at  the  fact  that  latex  is  occasionally  almost  absent  or 
possesses  a  low  percentage  of  rubber  globules  ;  it  is  a  variation 
which  must  be  expected,  considering  the  non-vital  functions  of  the 
latex  and  the  millions  of  the  same  species  already  planted  in  the 
East.  A  complete  explanation  of  this  variability  in  the  latici- 
ferous part  of  the  plant,  based  on  anatomical  or  phy-siological 
grounds,  has  not  been  put  forward,  and  in  the  meantime  this 
phenomenon  adds  one  more  to  the  perplexing  points  requiring 
solution.  We  are  left  to  explain  why  latex  tubes  occur  in  onlj-  a 
small  number  of  plants,  are  never  required  by  many  species,  and 
even  when  present  appear  to  have  no  vital  functions  to  perform. 
In  some  cases  they  remain  turgid  and  full  of  latex  when  most  other 
parts  of  the  plant  are  dead,  as  in  the  dead  stumps  observed  at 
Henaratgoda  and  Singapore. 

Functions  of  the  Latex. 
It  is  well  known  that  a  system  of  latex  tubes  may  or  may  not 
occur  in  different  species  of  plants,  and  that  the  presence  of  a  latici- 
fefous  system  is  of  importance  in  determining  the  identity  of  species- 
Several  natural  orders,  such  as  those  which  include  the  genera 
Euphorbia,  Castilloa,  Hevea,  Funtumia,  Landolphia,  etc.,  are 
characterised  by  large  numbers  of  plants  which  possess  latex  tubes, 
whereas  other  natural  orders  are  not  known  to  have  any  latici- 
ferous species.     It  is  also  recognized  that  the  number  of  species  of 


PARA     RUBBER  59 

plants,  possessing  latex  tubes,  is  greater  in  the  tropics  than  in 
colder  or  more  temperate  zones,  and  that  many  of  the  latex-bear- 
ing plants  thrive  on  rocky  soils  and  in  dry  districts  in  the  tropics. 

If  one  reflects  on  the  thriving  condition  of  widely  different 
species  of  latex-bearing  plants  in  the  temperate,  sub-temperate, 
and  tropical  regions,  and  the  behaviour  of  such  plants  under 
various  conditions,  the  difficulty  of  ascribing  a  single  function  or 
series  of  functions  to  the  latex  will  be  manifest.  Each  species 
must  be  considered  separately  ;  in  the  case  of  Hevea  brasiliensis 
many  observations  have  been  made  and  various  theories  pro- 
pounded. 

The  latex  of  I-Tcvca  consists  mainly  of  water  and  caout- 
chouc globules  together  with  small  quantities  of  sugars,  proteins, 
gums,  resins,  mineral  matter,  etc.  Most  of  the  constituents  cannot 
be  regarded  as  forming  reserve  food,  and  even  in  the  case  of  sugars 
and  proteins  their  presence  in  such  small  quantities  would  prevent 
their  being  of  vital  importance  to  the  plant  in  times  of  emergency. 
Furthermore,  the  fact  that  the  tubes  arise,  de  novo,  by  a  process  of 
perforation  and  decomposition,  and  along  their  ramifications  in 
the  cortex  are  never  in  direct  communication  but  contact  only 
with  the  vital  elements  of  the  bast,  supports  the  contention  that 
the  small  quantities  of  food  they  contain  are  probably  of  minor 
importance  to  the  plant. 

Groom  (Function  of  Laticiferous  Tubes,  Annals  of  Botany, 
1889),  when  dealing  with  this  subject,  pointed  out  that  there  was 
no  reason  to  believe  that  the  functions  of  the  latex  in  all  plants 
were  the  same,  or  that  one  function  should  exclude  the  other. 

Function  of  Storing  Water. 

The  water  is,  according  to  most  observers,  of  more  importance 
than  the  other  constituents.  It  is  well  known  that  the  flow  of 
latex  is  largely  determined  by  the  humidity  of  the  air  and  the 
quantity  of  water  present  in  the  soil.  The  increased  flow  which 
follows  rain  after  a  drought  is  often  very  remarkable  ;  this  may, 
or  may  not,  mean  an  increase  in  caoutchouc  during  these  periods. 

Warming,  after  studying  the  vegetation  of  tropical  America, 
concluded  that  the  latex  probably  served  many  functions,  one  of 
them  being  a  source  of  water-supply  during  the  dry,  hot  part  of  the 
day  or  year. 

Freeman  remarked  at  a  meeting  held  at  the  Royal  College 
of  Science,  London  (Indiarubber  Journal,  30th  December,  1907), 
that  one  viewi,  which  had  a  considerable  amount  of  evidence  to 
support  it,  was  that  tlie  latex  tissues  serve  as  a  place  for  storage 
of  water  to  be  drawn  upon  in  periods  of  drought.  It  has  been 
observed  that  trees  of  the  Central  American  {Castilloa  elastica) 
rubber  tree  growing  under  moist  conditions  develop  very  little 
latex,  i.e.,  yield  very  little  rubber,  whilst  trees  growing  under 
■drier  conditions  yield  latex  more  abundantly.  It  would  be 
reasonable  to  expect,  if  the  latex  is  really  functional  for  water 
■storage  purposes,  that  it  would  be  developed  to  the  greater  extent 
in  plants  living  under  such  circumstances   as  necessitate  their 


60  PARA     RUBBER 

drawing  on  storage  supplies  of  water  during  part  of  the  year.  That 
is  to  say,  rubber  plants  growing  in  countries  with  well-marked  dry 
seasons  would  have  greater  inducement  to  provide  the  water 
reserve  than  those  growing  in  continuously  humid  districts.  In 
the  latter  the  trees  would  thrive  and  grow  very  freely,  perhaps 
better  than  in  the  former,  but  they  might  yield  less  rubber  because 
conditions  are  too  well  suited  to  them. 

Freeman's  view  would  appear  to  be  contradicted  by  the 
results  obtained  in  the  wet  soils  of  the  F.M.S. 

Parkin  considered  that  the  latex  did  not  play  an  important 
part  in  nutrition,  and  inchned  to  the  behef  that  the  laticiferous 
system  served  as  a  channel  for  holding  water  in  reserve  to  be 
called  upon  during  times  of  drought.  ' '  Primarily, ' '  he  states, 
"the  latex  may  be  regarded  rather  as  a  waste  product,  and  the 
tubes  containing  it  as  genetically  related  to,  and  a  further  develop- 
ment of,  secretory  sacs.  But  the  substitution  of  an  extensive 
system  of  communicating  tubes  in  place  of  isolated  sacs  apparently 
implies  the  adoption  of  some  new  function,  in  addition  to  that  of 
removing  the  waste  products  of  metabolism.  A  conducting 
function  is  the  one  which  suggests  itself.  The  tubes  may  form 
channels  for  the  conveyance  and  storage  of  water.  Laticiferous 
plants,  at  any  rate  the  arborescent  ones,  are  distinctly  numerous 
in  the  tropics,  where  transpiration  at  times  is  excessive,  especially 
during  the  dry  season.  The  theory  of  water  storage  and  con- 
duction is  perhaps  the  most  plausible.  The  watery  nature  of  the 
latex  in  the  trunk  of  Hevea  has  been  noticed  to  be  affected  by 
the  state  of  the  soil.  When  dry,  the  latex  is  thicker  and  flows  out 
less  readily,  suggesting  that  the  tree  is  drawing  upon  the  reserve 
of  water  accumulated  in  the  laticiferous  tubes.  In  the  alluvial 
regions  of  the  Malay  States  the  tree  yields  latex  very  abundantly. 
Here  there  is  a  surplus  of  moisture  in  the  soil,  and  so  the  tubes  are 
always  well  distended  with  latex.  There  is,  in  fact,  no  need  to 
draw  upon  this  reserve. ' '  The  exudation  and  clotting  of  the  latex 
prevent  the  many  insects  entering  the  tree,  but  this  is  not  of  much 
importance. 

The  complete  stripping  of  the  cortex  from  the  base  up  to  5  feet, 
and  with  it  the  greater  part  of  the  laticiferous  system,  has  not,  in 
the  case  of  Hevea  hrasiliensis,  resulted  in  any  very  bad  effects  on 
the  tree. 

The  present  appearance  of  trees,  from  which  large  quantities  of 
latex  have  been  extracted,  is  such  as  to  confirm  the  belief  that 
the  latex  is  of  minor  importance  to  plants  freely  supplied  with 
water,  and  that  the  main  source  of  danger  hes  in  the  removal  of  the 
cortical  and  bark  tissues  often  effected  in  collecting  the  latex. 

It  should  be  recorded  that  Hevea  hrasiliensis  grows  exceedingly 
well  on  land  which  is  frequently  inundated,  and  in  some  parts  of 
Ceylon  I  have  seen  trees  with  their  tap  roots  and  a  large  proportion 
of  the  feeding  rootlets  permanently  under  water  and  yet  yielding 
over  10  pounds  of  rubber,  per  tree,  per  year.  An  abundant 
supply  of  water,  in  well-drained  land,  is  not  harmful  to  young 
Hevea  rubber  trees,  as  is  evidenced  by  the  large  5delds  obtained 


PARA    RUBBER  6i 

in  parts  of  Perak  and  Selangor  where  the  water-level  is  often  only 
six  inches  below  the  surface  and  the  trees  have  lost  their  tap  roots. 

Protective  Value  of  Latex 

Ridley  doubts  whether  the  latex  of  Hevea  rubber  trees  acts 
as  a  water  store  or  a  protection  against  drought  and  points  out 
that  though  many  laticiferous  plants  thrive  in  desert  areas,  the 
proportion  of  species  belonging  to  the  wet  tropical  districts  is 
relatively  high.  He  lays  emphasis  on  the  latex  as  a  protection 
against  the  intrusion  of  fungus  spores  and  insects  into  wounds, 
and  states  that  many  of  the  trees  of  the  equatorial  belt  are  provided 
with  either  latex,  resin  or  gum,  which  rapidly  exudes  when 
a  wound  is  made. 

Lloyd  in  his  paper  on  guayule  (Lectures  on  Indiarubber, 
page  139),  points  out  that  the  failure  to  exude  upon  wounding, 
in  that  plant,  appears  to  negative  the  view  that  it  serves  to 
protect  against  injury. 

Latex  as  a  Reserve  Food. 

In  the  accompanying  illustrations,  figures  i  and  2  represent 
the  latex  tubes  running  in  a  vertical  direction  through  the 
stem  of  Hevea  brasiliensis.  In  each  case  they  are  surrounded  by 
cells  which  naturally  store  up  reserve  food -materials,  and  in 
figure  2  curious  rod-like  bodies  are  seen  in  the  laticiferous  vessels. 
In  some  instances  the  latex  tubes  are  pitted,  so  that  a  transference 
of  solutions  may  be  effected  from  one  series  of  cells  to  the  other. 
Furthermore,  the  latex  tubes  often  run  very  close  to  those  elements 
of  the  wood  the  function  of  which  is  to  convey  watery  solutions 
from  the  roots  upwards.  Figure  4,  drawn  from  a  section  of  the 
fruit  waU  of  Carica  Papaya,  shows  the  proximity  of  the  water- 
conducting  elements  of  the  wood  to  the  latex  tubes,  the  latter 
-possessing  irregular  patches  of  coagulated  indiarubber.  In  figure 
3  the  general  outline  of  a  series  of  tubes  is  shown.  On  account  of 
these  relationships  one  may  be  inclined  to  attach  some  importance 
to  the  theory  that  the  latex  tubes  are  partially  connected  with 
conducting  functions.  Contact  between  laticifers  and  wood 
vessels  is,  of  course,  almost  impossible  in  healthy  mature  bark  of 
a  tappable  Hevea  tree  ;  the  close  association  of  these  elements  in 
the  embryo  and  seed-leaves  (cotyledons)  suggests  a  means  whereby 
the  latex  in  the  early  stages  may  be  used  as  food. 

But  the  fact  that  the  laticiferous  tubes  may  be  concerned  in 
conducting  solutions,  that  they  contain  in  their  earlier  stages  a 
certain  quantity  of  protoplasm,  and  that  nuclei  and  starch  grains 
may  be  occasionally  found,  does  not  exclude  the  view  that  they 
are  mainly  excretory  or  act  largely  as  water  reservoirs. 

Generally  speaking,  the  latex  tubes  contain  an  emulsion  of 
many  substances,  such  as  caoutchouc,  resin,  gum,  sugar,  proteins, 
alkaloids,  and  fats,  and  it  is  therefore  very  difficult  to  identify 
each  component  in  sections  under  the  microscope.  Schulerus 
•  observed  that  in  the  embryo  the  latex  is  rich  in  suspended  matters. 


;  V-^ 


Latex  Tubes   of  Hevea  hrasiliensis  (i  and  2)  and  Carica  Papaya  (3  and  4). 
A ,  Latex  Tubes  ;   B,  Water-conducting  Vessels. 


PARA'    RUBBER  63 

and  that  as  the  plant  grows  the  latex  becomes  more  watery.  He 
suggested  that  the  emulsion  of  substances  might  be  of  use  during 
the  early  stages.  He  also  noticed  that  after  germination  the 
laticiferous  system  becomes  prominent  owing  to  an  increase  in  the 
substances  in  suspension. 

Sachs  found  that  if  the  leaves  of  some  caoutchouc  plants  were 
subjected  to  continuous  darkness  the  quality  of  the  latex  was 
affected,  the  milk  becoming  less  opaque  ;  a  marked  change  was 
also  noticed  if  the  plants  were  deprived  of  carbonic  acid  gas. 

Haberlandt  and  others  found  that  in  some  plants  the  starch 
grains  disappeared  from  the  latex  tubes  if  kept  in  darkness  for  two 
or  three  weeks,  thus  suggesting  that  under  certain  circumstances 
the  occasional  starch  grains  may  be  converted  into  sugar  to  be 
used  by  the  plant.  The  possible  origin  of  caoutchouc  from  sugars 
should  also  be  borne  in  mind  at  this  juncture. 

The  presence  of  nuclei  in  certain  laticiferous  tubes,  absorption 
in  the  embryonic  stages,  the  close  association  of  latex  tubes  with 
conducting  elements  in  the  leaf,  and  the  occurrence  of  minute 
quantities  of  carbohydrates,  proteins,  fats,  and  peptonizing 
ferments,  certainly  support  the  idea  that  under  certain  conditions 
the  latex  contents  may  be  useful  to  the  plant.  These  substances 
are  present  in  very  variable  proportions,  and  the  percentage  of 
valuable  ingredients  in  the  latex  and  remaining  bark  often 
diminishes  as  the  result  of  tapping  operations ;  this  may  be 
accounted  for  by  the  demand  made  on  reserve  foods  in  Ihe 
immediate  vicinity  of  tapping  areas,  these  being  used  up  in  the 
production  of  new  cortex  to  replace  that  excised  in  tapping 
operations.  But  as  previously  pointed  out  the  occurrence  of  such 
material  in  very  small  quantities  prevents  one  from  attributing 
iindue  importance  to  the  "reserve  food"  conception. 

Spence  believes  that  caoutchouc  is  a  reserve  food- stuff  for 
the  plant  and  bases  his  theory  on  the  hydrocarbon  nature  of  this 
substance  and  the  presence  of  oxidising  enzymes  in  the  latex  ; 
furthermore,  he  found  that  young  trees  of  Ficus  elastica  drew  upon 
the  latex  when  grown  in  an  atmosphere  and  soil  free  from  carbon 
dioxide.  As  the  result  of  his  discoveries  in  connection  with  pro- 
teins and  enzymes  in  latices  and  rubber,  he  stated  that  caoutchouc 
is  "  a  reserve  food- stuff  for  the  plant  at  certain  stages  of  its  growth, 
which  is  broken  down  as  circumstances  demand,  by  the  enzyrnes 
associated  with  it  in  the  living  protoplasm,  into  the  simple  food- 
stuffs, the  sugars,  from  which  the  caoutchouc  is  almost  certainly 
formed  by  the  plant. ' '  In  support  of  his  theory  Spence  refers  to 
the  entire  disappearance  of  caoutchouc  in  the  latex  of  an  African 
plant  when  the  rainy  season  commences  and  its  reappearance  at 
the  end  of  the  rains  ;  his  inference  from  this  and  allied  phenomena 
is  that  the  caoutchouc  is  used  in  the  metabolic  processes  of  the 
plant.  Parkin  states  that  physiologists  will  require  much 
evidence  before  accepting  such  a  novel  theory. 

Petch  observes  that  if  a  fallen  Hevea  leaf  be  taken,  and  a 
thin  layer  of  the  midrib  on  the  back  of  the  leaf  be  slowly  peeled 


64  PARA      RUBBER 

off,  strands  of  rubber  appear  between  the  midrib  and  the  strip 
that  is  being  peeled  off.  Rubber  can  also  be  extracted  from 
fallen  leaves  with  carbon  bisulphide.  Now,  when  a  tree  sheds 
its  leaves,  all  the  potash,  phosphoric  acid,  starch,  etc.,  in  them  has 
been  absorbed.  The  dead  leaf  contains  only  waste  products  ; 
therefore  rubber  is  probably  a  waste  product. 

The  physiological  effect  of  extracting  large  quantities  of  latex 
from  trees  of  known  age  is  being  studied  in  the  East,  but  up 
to  the  present  no  remarkable  phenomena  have  been  observed. 
Where  the  bark  is  regularly  cut  away  it  is  impossible  to  determine 
the  effect  of  removal  of  latex  only,  as  the  loss  of  Uving  bark  con- 
taining abundant  supplies  of  reserve  food  is  obviously  a  far  more 
important  factor.  If  incision  experiments  only  are  carried  out, 
and  all  primary  bark  preserved,  it  may  then  be  possible  to  determine 
the  effect  of  removing  the  latex  on  the  quantity  of  reserve  food- 
stuffs in  adjacent  tissues.  Even  then  it  would  be  necessary  to 
remove  large  quantities  of  latex  and  to  make  due  allowance  for 
the  usual  metabolic  changes  daily  occurring  in  all  living  cells. 


CHAPTER    IV. 

CLIMATIC    CONDITIONS    FOR    HEVEA    BRASILIENSIS. 

Para  (Notes  on  Rubber-jdelding  Plants,  by  Trimen)  occupies 
a  position  near  the  mouth  of  one  of  the  vast  embouchures  of  the 
Amazon  in  about  south  latitude  i,  but  the  district  of  the  same 
name  extends  over  a  vast  forest  region  to  the  south  and  west, 
throughout  which  and  the  enormous  forests  of  Central  and  Northern 
Brazil,  Hevea  hrasiliensis  and  allied  sp'ecies  are  abundantly  found. 
The  climate  is  remarkable  for  its  uniformity  of  temperature, 
usually  not  exceeding  87°F.  at  midday  or  falling  below  74°  at  night. 
The  greatest  heat  recorded  is  95°,  and  the  mean  for  the  year  is 
81°  The  rainfall  occurs  principally  during  the  months  from 
January  to  June,  the  maximum  being  in  April,  when  it  reaches  15 
inches  ;  for  the  remaining  six  months  of  the  year  very  Uttle  rain 
falls,  but  there  are  fine  days  in  the  wet  season  and  occasional 
showers  in  the  dry.  During  the  wet  season  much  of  the  low-lying 
country  near  the  Amazon's  mouths  is  flooded. 

Ule  (Review  by  Willis,  "T.A.,"  March,  1905),  in  his  book 
dealing  with  rubber  in  the  Amazon  district,  points  out  that  ' '  the 
Para  tree  loses  its  leaves  annually  as  in  Ceylon,  and  in  the  flooded 
regions  this  occurs  when  the  water  is  at  its  highest,  i.e.,  between 
March  and  July.  It  flowers  in  July  and  August,  and  ripens  its 
fruit  in  January  and  February.  Like  most  forests  in  the  tropics 
those  of  the  Amazon  are  composed  of  many  kinds  of  trees  inter- 
mixed, and  rubber  occurs  scattered  among  the  rest.  The  lower- 
l3ring  forests  (vargem  or  igapo)  are  exposed  to  yearly  floods  and 
have  a  distinct  character,  differing  from  those  on  the  higher  lands. 

"  There  are  two  chief  seasons,  a  dry  and  a  wet.  The  driest 
months  are  July,  August,  and  September,  when  the  river-level  is 
also  lowest.  The  rains  begin  in  October  and  last  till  March,  and 
then  decrease ;  the  rain  is  not,  however,  continuous ;  there  are 
showers  with  clear  intervals.  The  rivers  rise  till  in  January  they 
overflow  into  the  forest ;  their  highest  level  is  reached  in  March 
or  April,  and  then  they  fall,  leaving  the  woods  dry  again.  In  the 
lower  course  of  the  Amazon  itself  the  water  reaches  its  highest 
level  in  June,  and  this  level  is  often  45  to  60  feet  above  the  lowest. 
The  annual  rainfall  is  usually  between  80  and  120  inches,  and  the 
mean  temperature  between  76°  and  8i°F.  There  are  a  great  many 
kinds  of  trees  in  the  forests,  and  in  a  distance  of  100  yards  one 
may  only  find  one  or  two  rubber  trees. ' '  ^ 


25° 

68 

243 

^P 

300 

287 

33° 

361 

igi 

269 

rzg 

133 

76 

51 

46 

16 

39 

14 

100 

16 

162 

13 

261 

42 

2127 

1463 

{85-0  in.) 

(59-5  m. 

66  PARA     RUBBER 

Rainfall  in  Para,  Manaos  and  Ceara. 
The  following  statistics  are  given  by  Leplae  in  his  account  ot 
Hevea  cultivation  : — 

Para.  Manaos.  Ceara. 

mm 

January  263 

February- 320 

March 338 

April     336 

May      237 

June     144 

July      125 

August     108 

September  82 

October    63 

November   59 

December    129 

Total    2204 

(88-2  in.) 

It  must  be  understood  that  Ceara  is  the  home  of  the  rubber 
of  that  name  and  is  outside  the  Hevea  areas. 

Hevea   Trees  in  Brazil. 

It  has  been  pointed  out  by  Wickham  that  the  true  forests  of 
the  Hevea  trees  lie  back  on  the  highlands,  and  those  commonly 
seen  by  travellers  along  the  river  side  are  scattered,  poor  in  growth, 
and  do  not  give  one  a  fair  idea  of  the  conditions  under  which  a 
good  growth  of  the  Hevea  tree  is  obtained.  The  Hevea  trees 
found  in  these  forests  attain  a  circumference  of  10  to  12  feet  in  the 
bole,  a  considerable  difference  to  the  6  or  7-foot  trees  recorded  by 
Cross. 

The  foregoing  accounts  of  the  climatic  conditions  in  the  native 
home  of  Hevea  brasiliensis  should  be  closely  studied  by  those 
who  intend  to  cultivate  this  tree.  The  rainfall  of  80  to  120- 
inches  and  temperature  of  75°  to  81  °F.,  though  characteristic  of 
the  forests  where  this  species  grows  luxuriantly,  should  not, 
however,  be  accepted  as  strictly  defining  the  limits  under  which 
Hevea  trees  can  be  grown.  But  even  if  the  adaptability  of  the 
tree  were  insignificant,  it  is  obvious  that  in  the  tropics  there  are 
many  areas  which  might  reasonably  be  expected  to  give  good 
results  with  this  species  of  rubber.  Already  the  cultivation  has 
aroused  considerable  interest  in  Africa,  Fiji,  Java,  Queensland, 
Seychelles,  Borneo,  Samoa,  Sumatra  ;  and  in  many  of  these  areas 
where  the  chmatic  factors  are  approximately  similar  to  those  of 
the  Amazon,  the  industry  promises  to  become  as  important  as  in 
Malaya,  Ceylon,  and  India. 

Climate  in  Ceylon. 

The  combination  of  rainfall,  temperature,  and  elevation, 
required  for  the  cultivation  of  Hevea  brasiliensis  eliminates  man^' 
parts  of  the  tropics  for  this  species.     In  Ceylon,  India,  and  the 


PAPA     RUBBER  67 

Straits  the  large  tracts  of  land  in  the  hilly  districts  cannot  be 
included  in  the  Hevea  zone  on  account  of  low  temperatures  or 
unfavourable  moisture  conditions.  In  Ceylon  an  elevation  of 
2,000  feet  in  the  Central  Province,  and  3,000  feet  in  the  Uva 
Province,  is  considered  to  be  near  the  maximum  and  a  rainfall  of 
70  inches  near  the  minimum  for  the  cultivation  of  this  species. 
There  are  trees,  planted  in  1899,  measuring  18  to  26  inches  in  girth 
and  22  to  33  feet  in  height,  growing  on  Weweltalawa,  Halgolle 
estate,  on  the  borders  of  the  Kelani  Valley  and  Yakdessa  chstricts, 
at  an  elevation  of  3,300  feet.  It  is  being  tried  in  districts  having 
200  inches  of  rain  per  year  and  also  in  dry  irrigable  areas,  but 
reliable  results  cannot  be  obtained  there  for  many  years. 

The  following  are  the  meteorological  details  of  places  in 
particular  districts  in  Ceylon  where  Hevea  rubber  trees  are  being 
SLCcessfuUy  grown  (Surveyor-General's  Report,  1902,  and  by 
letter)  : — 

Annual  Average 

District.  Rainfall.  Annual  Elevation. 

Inches.         Temperature  Feet. 

Kalutara  (Gikiyaua- 

kanda)      15074  —  2°° 

Colombo 8y52  807  F.  40 

Henaratgoda  106-12  —  33 

Kelani      i6i'o6  —  250 

Kurunegala     8471  —  409 

Kegalla    122'33  —  729 

Kandy      81-52  75-5  1,634 

BaduUa    75'28  73-4  2,225 

Passara    88-91  —  2,800 

Matale      84-38  —  1,208 

Ratnapura i5i'39  79'i  84 

Galle     91-16  799  48 

Ragama 100-03  79-5  — 

In  the  Colombo,  Galle,  Ratnapura,  Kelani,  and  Kalutara  Dis- 
tricts the  rains  in  the  N.E.  and  S.W.  monsoons  are  very  heavy  ;  in 
the  Kurunegala,  Matale,  BaduUa,  and  Passara  Districts  they  are 
less  violent,  but  in  all  the  districts  mentioned  above  rain  falls 
every  month  in  the  year,  the  monthly  variation  being  from  about 
five  to  twenty-four  inches. 

Climate  in  South  India. 

In  some  parts  of  India  the  climatic  conditions  are  such  as  to 
allow  of  the  cultivation  of  Hevea  trees  up  to  3,500  feet  above  sea- 
level,  and  what  appear  to  be  satisfactory  rates  of  growth  are 
reported  from  many  parts.  Extensive  tracts  of  country  are  being 
opened  up,  especially  in  the  Travancore  district,  and  good  results 
are  anticipated  on  account  of  the  abundance  of  rich  alluvial  soil 
which  is  reported  to  exist  there. 

Curiously  enough,  we  must  pass  around  to  the  West  Coast  to 
find  a  climate  at  all  resembling  that  in  the  rubber-growing  districts 
of  Ceylon.  There  is  a  strip  of  country  between  the  hills  and 
the  coast  that  is  suitable,  though  there  are  also  some  outlying 
parts  more  to  the  east  only  a  little  less  desirable.     An  area  of 


68  PARA    RUBBER 

annual  rainfall  averaging  above  75  inches  lies  between  the  coast 
and  a  line  roughly  parallel  with  it  passing  northwards  from 
Quilon.  It  includes  the  extreme  north-west  corner  of  Travancore, 
Cochin  State,  Malabar,  part  of  the  Nilgiris,  Coorg,  a  corner  of 
Mysore,  Canara,  and  Goa  (15°  N.  lat.)  A  narrower  area  of  annual 
rainfall  averaging  above  100  inches  included  in  this  lies  between 
the  coast  and  a  line  roughly  parallel  with  it  passing  northwards 
from  Cochin  Town.  It  includes  Cochin  State,  Malabar,  less  of 
the  Nilgiris  and  of  Coorg  and  Mysore,  and  Canara  and  Goa. 
But  the  northerly  parts  of  these  areas  is  marked  by  a  very  pro- 
nounced dry  season,  and  even  in  Coorg  the  average  rainfall  for 
the  whole  period  of  four  months — December  to  March — at  the  ten 
Meteorological  Stations  is  only  0-949  inches,  with  that  at  the 
highest  station  only  1-69  inches.  Within  these  areas  the  average 
number  of  rainy  days  in  the  year  is  between  100  and  125  ;  except 
close  to  Cochin  Town,  where  the  rainfall  is  better  distributed  and 
the  dry  season  less  pronounced,  the  number  being  greater. 

As  the  following  table  shows,  the  climate  in  Cochin  district  is 
not  widely  different  from  that  in  the  rubber-growing  parts  of 
-Ceylon  : — 

Meteorological    Details,    Cochin. 


January 

February 

March 

April 

May 

June 

July 

Some  Hevea  rubber  in  coffee  has  done  well  in  the  Anamallai 
Hills  at  an  elevation  of  3,500  feet  above  sea-level  ;  and  the  results 
of  tapping  on  an  estate  in  the  Shevaroy  HiUs  are  given  in  one  of  the 
chapters  dealing  with  jdelds.  It  is  as  well  to  bear  in  mind  that 
the  elevation  up  to  3,500  feet,  in  so  far  that  it  is  related  with 
changes  of  atmospheric  pressure,  has  very  little  influence  on  the 
growth  of  the  rubber  ;  far  more  important  are  the  questions  of 
ranges  of  temperature  and  rainfall. 

The  Climate  in  the  Federated  Malay  States. 

In  the  Federated  Malay  States  there  is  no  evidence  of  the 
highest  elevation  at  which  Hevea  trees  will  thrive,  though  some 
young  trees  are  growing  at  Gunong  Angsi  at  an  elevation  of  2,500 
feet.  According  to  Carruthers  the  growth  of  Hevea  rubber  from 
sea-level  up  to  300  feet  in  the  Federated  Malay  States  is  better 
than  that  at  other  elevations. 

According  to  the  Manual  of  Statistics  published  by  the 
Federated  Malay  States  Government ' '  the  climate  of  the  Federated 
Malay  States  is  very  uniform  and  can  be  described  in  general 


Average 

monthly 

temperature. 

°Fahr. 

Average 
monthly 
rainfall. 
Inches. 

Average 
monthly 
temperature. 
"Fahr. 

Average 
monthly 
rainfall. 
Inches. 

79-5 
809 

82-5 
84-0 
82-5 

o-8o 
o-8o 

2-12 

5-24 
I2'00 

August 

September 

October 

November 

December 

77'9 
78-5 
79-1 
80-2 
79-9 

12-44 
8-74 

12-46 
5-16 
1-72 

787 
77'3 

30-12 
21-71 

Annual 

80-1 

113-31 

PARA     RUBBER  69 

terms  as  hot  and  moist.  The  annual  rainfall,  except  in  places 
close  to  the  mountain  ranges,  is  about  90  inches.  In  towns,  such 
as  Taiping,  Tapah,  Selama,  etc.,  close  to  high  mountains,  upwards 
of  50  per  cent,  more  is  registered,  the  average  of  ten  years'  records 
at  the  first-named  being  164  inches.  There  is  no  well-marked  dry 
season.  Generally  speaking,  July  is  the  driest  month,  but  has 
seldom  a  less  rainfall  than  3^  inches.  The  wettest  season  is  from 
October  to  December,  and  there  is  another  wet  season  of  slightly 
less  degree  during  March  and  April.  Rain  rarely  falls  before 
II  a.m.,  so  that  6  hours  of  outdoor  work  can  generally  be  depended 
upon  all  the  year  round. 

"The  average  maximum  temperature,  occurring  between  noon 
and  3  p.m.,  is  in  the  low-country  just  under  90°,  and  the  average 
minimum  occurring  before  sunrise  is  just  over  70°.  The  general 
mean  temperature  is  about  80°.  There  is  very  little  change  in  the 
mean  monthly  temperature  during  the  year,  the  average  of  ten 
years'  readings  in  Taiping  exhibiting  a  difference  of  only  3'2° 
between  the  mean  temperature  of  May,  the  hottest,  and  of 
December,  the  coldest  month  of  the  year. 

"  The  variation  of  temperature  with  altitude  may  be  taken 
roughly  as  a  decrease  of  3°  for  every  1,000  feet  increase  of 
altitude." 

Average    Rainfall   at    Perak,    Selangor,    Seremban. 

Perak  Selangor         Negri-Sembilan 


January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December 


(Teluk  Anson) ,    (Kuala  Lumpur),    (Seremban), 

1894-1903.  1894-1903.  1896-1903. 

IO-6I  667  5'2i 

7"28  6'29  6'46 

8-II  9-29  8-45 

8-85  1079  io'56 

7-40  9-13  7-81 

5'56  5'94  5'97 

4'20  4'o6  4'59 

5-10  6-14  5-96 

6-51  874  5-95 

i3'5i  1315  9T9 

I2-59  if87  io'24 

i.3'27  9'95  763 


Mean  Total..  i03'oi  io2"02  88'02 

The  above  details  of  rainfall  will  be  of  value  to  all  interested 
in  the  cultivation  of  Hevea  rubber  in  Perak,  Selangor,  and 
Seremban. 

Rainfall  in  Kelantan. 

According  to  the  Administration  Report  for  1909,  the  follow- 
ing are  the  rainfalls  for  parts  of  Kelantan  : — 


Kota  Bahru. 

Kuala  Lebir, 

Kuala  Kelantan. 

Inches. 

Inches. 

Inches. 

1907 

108-37 

120-54 

104-40 

1908 

10913 

95'i6 

10640 

rgog 

90-09 

73'09 

89-56 

70 


PARA     RUBBER 


Singapore,  Penang,  and  Malacca. 
I  am  indebted  to  the  Principal  Civil  Medical  Officer  of  Singa- 
pore for  the  following  statement  showing  the  average  monthly 
Rainfall,    Temperature,    and    Humidity    at    Singapore,    Penang, 
and  Malacca  : — 


Rainfall. 

Temperature. 

Hu 

rmdi 

t}- 

s 

"is 

i 

C 

bo 

c 
a 

u 
0 

5 

ti 
C 

0 
0 

ffi 

& 

S 

tn 

flH 

S 

'tSi 

Ah 

f^ 

Inches. 

Inches. 

Inches. 

°F. 

°F. 

°F. 

% 

% 

0' 

/o 

January- 

I3'47 

4'26 

4-15 

78-2 

8o-8 

79-2 

81 

71 

94 

February 

7'26 

2 '59 

5-36 

78-4 

80-7 

79-1 

78 

69 

92 

March 

575 

4'I3 

262 

79-7 

8i-5 

79-6 

77 

69 

93 

April 

1075 

6-82 

6'42 

80-5 

81-2 

79-7 

80 

73 

93 

May 

4'93 

g-oi 

6'27 

8i-3 

8o-8 

79-6 

78 

72 

94 

June 

6'50 

8-27 

6-21 

81-0 

80-9 

79-7 

79 

72 

94 

J"iy 

6'6o 

919 

6-66 

80-9 

80-2 

79-5 

78 

72 

94 

August 

877 

13-58 

912 

80-5 

79-9 

77-6 

78 

73 

94 

September 

4'65 

14-54 

8-36 

80-6 

79-9 

79-2 

78 

72 

92 

October 

5-60 

15-82 

12-86 

8o-i 

79-7 

79-4 

79 

74 

94 

November 

873 

lO'OI 

10-74 

79-1 

80-0 

79-2 

81 

73 

94 

December 

6-96 

5-14 

5-33 

78-3 

79-9 

79-1 

80 

73 

92 

Climate  in 

Sumatra. 

The  following  statistics  relating  to  the  i^ainfall  on  well-known 
and  advanced  Hevea  estates  in  the  Langkat,  Serdang,  and  Bandar 
districts  of  Sumatra  should  prove  of  interest  : — 


Rainfall,   1910 

Serdang 

Langkat 

District. 

Bandar 

Month. 

District. 

District. 

(Baloewa.) 

(Glen  Bervie.) 

(Soengei  Roean) 

(Pinang.) 

Inches. 

Inches. 

Inches. 

Inches. 

January 

9 

24 

I& 

'        54 

February 

13 

9 

14 

iij 

March 

?■■ 

8 

x&i 

7 

April 

12 

94 

20 

9 

May 

f:^ 

15 

174 

13 

June 

13- 

1 

74 

13 

July 

II   ; 

6 

ik 

8 

August 

15  1 

9 

§ 

14  • 

September 

II 

44 

14 

II 

October 

18; 

11 

244 

21 

November 

9. 

104 

30 

4 

December 

16 

10J 

32 

13 

146 


97^ 

Java. 


210J 


1281 


The  climate  in  Java  varies  Hke  that  in  Ceylon  according  to  the 
locality ;  we  have  definite  information  regarding  the  climatic 
factors  at  Buitenzorg  and  East  Java. 


PARA     RUBBER 


71 


The  climate  at  Buitenzorg  differs  from  that  at  Peradeniya, 
Ceylon,  in  many  ways.  At  Buitenzorg  the  rain  during  1901  to 
1904,  inclusive,  fell  on  an  average  of  263  days  in  each  year.  The 
humidity  of  the  air  in  1904  ranged  from  75  in  August  to  85  in 
December,  and  the  average  for  the  years  1901  to  1904,  inclusive, 
was  79.  The  average  monthly  temperature  ranged  in  1904  from 
23"6  to  25 ^"C.  The  climate  in  Buitenzorg  is  more  equable  than 
that  at  Peradeniya,  but  a  definite  periodicity  does  exist,  the 
rainfall  and  humidity  throughout  the  year  approximating  to 
those  at  Badulla  in  the  Uva  Province  of  Ceylon. 

In  East  Java  the  climate  is  more  exacting,  and  a  comparison 
of  the  two  places  is  given  below. 

I  was  indebted  to  the  late  Dr.  Treub  for  the  information  in 
the  following  synopsis  of  the  monthly  rainfall,  humidity,  and 
temperature  at  Pasoeroean  in  East  Java  and  Buitenzorg. 

Rainfall  during  1904  in  Java. 


Buitenzorg. 

East  Java 

Buitenzorg. 

East  Java 

mm. 

mm. 

mm. 

mm. 

January  . 

417 

221 

August     . .             344 

18 

February. 

455 

192 

September              388 

— 

March 

169 

287 

October    .  .             799 

II 

April 

204 

33 

November              312 

24 

May 

541 

155 

December              498 

no 

June 

389 

27 

Average 

July 

312 

48 

mean,  yearly 

1901 — 1904         4,416 

1, 200 

The  following  were  the  monthly  rainfalls,  in  inches,  from 
January  to  December,  1910,  on  Soember  Tengah  estate,  East 
Java  : — 11,  9f,  15 J,  9I,  7,  4f,  5 J,  if,  ij,  6,  i2-|,  and  13,  making 
a  total  of  97f  inches  for  the  year. 

I  am  informed  by  Mr.  R.  C.  Wright  that  probably  the  best 
parts  of  Java  for  rubber-growing  are :  a  portion  of  Bantam  ;  a 
great  part  of  the  Preanger  ;  a  portion  of  south-east  Java  ;  and 
perhaps  also  a  portion  of  the  north  side  of  Mid- Java.  In  some  of 
these  areas  the  temperature  at  about  1,000  feet  altitude  varies  from 
68°F.  to  90°F  ;  the  humidity,  except  in  a  portion  of  Mid- Java,  is 
high. 

Conditions  in  Borneo. 
The  late  Mr.  Cowie  informed  me  that  the  average  yearly 
rainfall  in  British  North  Borneo  rubber-growing  districts,  on  the 
coast,  is  about  120  inches.  In  the  interior,  immediately  behind 
the  great  central  range  of  mountains,  the  average  yearly  rainfall 
is,  according  to  Mr.  Lease,  Manager  of  the  Sapong  Rubber  and 
Tobacco  Company,  only  about  70  inches  per  annum. 

According  to  the  report  of  Mr.  Berkhuysen  the  rainfall  in 
the  interior  during  1906  was  62.34  inches.  The  same  authority 
gives  the  average  temperature  at  90°F.  during  the  day  and  70°F. 
during  the  night,  in  his  district. 


f% 


PARA    RUBBER 


On  the  coast  the  temperature  averages  about  85°F.  during 
the  day  and  about  8o°F.  at  night. 

The  following  are  the  details  of  the  monthly  rainfall  from 
July  1910  to  June  igii,  on  Sekong  Estate: — 5'52,  ii'O,  i2'4, 
4-2,  7-6,  6-6,  117,  8-3,  2-II,  5-96,  573,  and  575  inches,  making  a 
total   of   86-87   inches. 

Climate  in  New  Guinea. 
Though  it  is  the  second  largest  island  in  the  world,  and 
the  rainfall  and  temperature  are  suitable  in  so  many  parts. 
New  Guinea  has  as  yet  only  a  small  acreage  under  rubber.  The 
growth  so  far  reported  is  very  good.  Below  are  given  the  results 
of  observations  at  stations  in  Papua  and  German  New  Guinea  : — 


Sogeri. 
Average 
Rainfall 

Grima. 

Average 

Rainfall 

Sogeri. 

Average 

Rainfall 

Grima. 
Average 
Rainfall 

1902-4. 
Inches. 

1893-4. 
Inches. 

1902-4. 
Inches. 

1893-4. 
Inches. 

January  . . 

February. . 

March 

April 

May 

\  une 

]  uly 

9.247 
12.023 

13-797 

10.616 

6.812 

4917 

1-332 

14.272 

"■535 
12.382 
14.567 
11.063 
6.220 
6.988 

August     . . 
September 
October    . . 
November 
December 

Annual     , . 

3-520 
5-383 
5-852 
5-450 
17.424 

5-571 

4-035 

6.968 

18.071 

17.421 

92.606 

128.487 

Sogeri  is  at  a  height  of  1,600  feet  and  is  near  to  the  dry-belt 
district  around  Port  Moresby  ;   Grima  is  on  the  North  Coast. 

Climate  in  Cochin-China. 

It  is  claimed  (J.  d'Agr.  Trop.,  November,  1910,)  that  the  dry 
season,  from  January  to  April,  does  not  sensibly  retard  the  growth 
of  the  trees.  The  effects  of  the  dryness  are  said  to  be  counter- 
acted by  the  abundance  of  dews  and  by  the  physical  properties  of 
the  soils,  especially  the  red  types,  which  always  preserve  a  great 
degree  of  moisture  at  no  great  depth.  Mathieu  and  Deleurance 
consider  that  this  dryness  lessens  notably  the  cost  of  weeding, 
and  the  former  claims  that  it  is  favourable  to  plant  sanitation. 
One  may  remark  that  if  there  is  any  considerable  force  in  these 
claims,  there  does  not  seem  to  be  any  promise  of  good  growth  of 
rubber  trees. 

Climate  of  the  Seychelles,  Fiji  Islands  and 
Philippines. 

Lying  at  about  4°S.  latitude,  the  Seychelles  Islands  possess  a 
favourable  temperature,  the  mean  being  about  83 °F.  The 
average  annual  rainfall  at  Port  \'ictoria  amounts  to  ioi"24  inches, 
of  which  70  per  cent,  falls  within  the  period  from  November  to 
March,  both  months  inclusive.  Yet  this  leaves  more  than  30 
inches  for  the  seven  months  remaining. 

Situated  further  from  the  equator,  between  i6°S.  latitude  and 
i8°S.  latitude,  the  Fiji  Islands  have  a  mean  temperature  only  three 


PARA    RUBBER  73 

degrees  less,  yet  a  temperature  that  is  not  so  equable.  The 
rainfall  at  Suva  for  the  years  1905,  1906,  1907,  and  igo8  was  73'03 
inches,  i69'62  inches,  I47'49  inches,  and  104-85  inches  respectively. 
Hurricanes  sometimes  occur,  destroying  the  crops. 

The  Philippines  also  are  liable  to  severe  wind-storms.  Though 
they  stretch  from  7°N.  latitude  to  I9°N.  latitude,  the  temperature 
seems  everywhere  to  be  favourable,  but  it  is  only  south  of  the 
fourteenth  parallel  that  a  fairly  even  distribution  of  rainfall 
occurs,  as  in  some  regions  of  Luzon,  the  Eastern  Viscayas,  Mindanao 
and  Jolo.     The  average  annual  rainfall  at  Manila  is  75 '491  inches. 

Climate  in  Samoa. 

The  Samoan  Islands  possess  a  tropical  and  very  equable 
climate.  The  usual  range  of  temperature  is  from  68°  to  88°F. 
According  ±0  one  authority  (Bulletin,  Imperial  Institute,  London, 
March,  1904,)  "violent  winds  and  thunderstorms  are  not  of 
frequent  occurrence,  but  severe  hurricanes  sometimes  sweep  oyer 
the  islands,  though  only  in  every  seven  to  nine  years.  The 
dampness  of  the  air  is  not  so  great  as  would  be  expected  in  tropical 
islands,  but  it  is  high  enough  to  meet  the  requirements  of  all 
moisture-loving  tropical  plants.  In  the  rainy  season,  which  lasts 
from  November  to  March,  the  air  is  usually  almost  saturated.  The 
mean  annual  rainfall  at  Apia  for  the  13  years,  i8go  to  1902,  is 
115  inches,  and  the  extremes  in  that  period  are  a  minimum  of  89 
inches  and  a  maximum  of  163  inches.  On  the  coast  the  rain  is 
not  well  distributed  in  the  course  of  the  year,  and  there  are  years 
when  periods  of  drought  last  too  long  and  are  too  intense  to  suit 
the  needs  of  the  cacao  plant."  According  to  Wohltmann  the 
climate  in  different  parts  of  Samoa  is  very  variable,  the  rainfall 
of  selected  places  ranging  from  1,600  to  3,500  mm.  per  year,  and 
should  therefore  be  as  suitable  for  Hevea  rubber  trees  as  it 
undoubtedly  is  for  cacao  trees. 

Upon  one  of  the  properties  belonging  to  the  Upolu  Rubber 
and  Cacao  Estates,  Ltd.,  the  monthly  rainfalls  in  1910  were  :  11 -8, 
i6-4,  27-6,  14-3,  ii-o,  5-3,  1-4,  4-0,"' 7-5,  147,  19-4,  34-6  inches, 
a  total  of  167-9  inches.  Upon  another  property  the  total  was 
144-3  inches,  apportioned  as  follows:  14-8,  19-2,  24-1,  12-3,  7-8, 
4-5,  0-6,  3-5,  7-8,  7-0,  14-7,  28-1  inches.  Such  a  rainfall  is  ample 
for  the  cultivation  of  Hevea. 

Climate  in  Africa. 

In  West  Africa  are  two  strips  of  territory  along  and  near  to  the 
coast  where  there  is  an  abundant  rainfall.  One  of  these  extends 
through  Southern  Nigeria  and  the  Cameroon  ;  the  other  stretches 
through  Sierra  Leone,  Liberia,  and  the  Ivory  Coast.  Outside 
these  territories,  as  in  the  Congo  Free  State,  are  isolated  areas  that 
are  suitable.  In  those  parts  of  Sierra  Leone  and  Liberia  nearest 
to  the  coast  the  rainfall  may  be  over  160  inches  per  annum. 
Further  inland,  and  reaching  from  coast  to  coast  on  either  side, 
is  an  area  where  the  rainfall  may  be  from  120  to  160  inches  ;    and 


74  PARA     RUBBER 

this  IS  true  also  of  the  coast  territory  in  Southern  Nigeria  and  the 
Cameroon.  Behind  both  these  areas,  and  also  reaching  from  coast 
to  coast  on  either  side,  are  areas  with  a  rainfall  between  80  and 
120  inches.  Between  the  two  strips  of  territory  he  the  Gold 
Coast  and  Togoland,  where  the  rainfall  is  not  very  liberal,  though, 
as  will  be  seen  below,  some  success  with  Hevea  is  reported. 

On  the  estate  of  the  Liberian  Rubber  Corporation  an  annual 
rainfall  of  over  120  inches  is  reckoned  upon. 

Climate  on  the  Gold  Coast  and  in  Nigeria. 

In  the  Gold  Coast,  West  Africa,  the  Hevea  tree  is,  according 
to  Johnson,  being  grown  at  an  elevation  of  1,500  feet  above  sea- 
level,  where  the  average  mean  temperature  is  about  8i'5°F.  and  the 
annual  average  rainfall  only  47  inches,  and  there  promises  to  do 
better  than  other  rubber-producing  plants,  indigenous  or  exotic. 

The  following  table  shows  the  rainfall  and  number  of  days  on 
which  rain  fell  during  1902-1904,  at  Aburi,  Gold  Coast  : — 


[902. 

1903. 

1904. 

No.  of 

No.  of 

No.  of 

Rainfall. 

Wet  Days. 

Rainfall. 

Wet  Days. 

Rainfall. 

Wet  Days 

Inches. 

Inches. 

Inches. 

Inches. 

Inches. 

Inches. 

January 

o'30 

I 

073 

I 

I  "00 

I 

February 

503 

5 

I  09 

3 

055 

2 

March 

•        .V82 

9 

5-89 

6 

4-i6 

8 

April 

7-01 

10 

2-63 

9 

184 

5 

May 

•        3-27 

10 

4-56 

8 

6-24 

9 

June 

709 

II 

7'44 

II 

6-47 

13 

July 

2-07 

6 

372 

13 

219 

7 

August 

293 

7 

1-58 

10 

065 

3 

September   . 

073 

2 

193 

II 

2-97 

6 

October 

7'i6 

II 

478 

13 

220 

8 

November   . 

2-i6 

2 

660 

14      , 

052 

4 

December     . 

0-74 

3 

213 

5 

3-30 

5 

42-31  77  43'o8  104  3209  71 

(Annual  Report  for  1904  by  Director,  Botanic  Department, 
Gold  Coast.) 

The  following  are  the  annual  statistics  regarding  rainfall 
from  1905  to  1909  at  Aburi  : — 1905,  36-87  inches  ;  1906,  4784 
inches  ;  1907,  50-73  inches  ;  1908,  5492  inches,  and  1909,  49-23 
inches.  At  the  Tarquah  Experimental  Station,  where  Hevea 
trees  are  planted,  the  rainfall  was  as  follows  : — 1904,  68-12  inches  ; 
1905,  70-66  inches  ;  1906,  53-96  inches  ;  1907,  74-35  inches  ; 
1908,  81-84  inches  ;  1909,  7604  inches.  At  Akim,  another  centre 
for  Hevea,  during  the  years  1908  and  1909  the  rainfall  was  70-8, 
and  80-19  inches  respectively.  At  Coomeissie,  a  distributing 
centre  for  seedlings  and  seeds,  the  rainfall  in  1906,  1907,  1908, 
and  1909  was  75-33,  52-08,' 6i-io,  and  5347  inches  respectively. 

The  rainfall  is  much  more  generous  in  parts  of  the  Southern 
Province  of  Nigeria,  where  a  rainfall  of  even  165-97  inches  was 
recorded  at  one  centre  in  1909.  In  the  same  year  at  Lagos, 
which  is  nearer  to  the  drier  belt  on  the  Gold  Coast,  the  rainfall 
was  67-59  inches  ;  at  Calabar  it  was  150-24  inches. 


PARA     RUBBER  75 

Climate  in  Togo  and  East  Africa. 

The  adaptability  of  Hevea  and  its  continued  growth  under 
widely  different  climatic  and  soil  conditions  is  evidenced  by  the 
results  obtained  in  many  countries.  Warburg  states  (Lectures 
on  Indiarubber),  that  in  the  German  colonies  Hevea  has  been 
grown  in  climates  characterised  by  definite  dry  seasons.  Even 
in  East  Africa  where  there  was  a  very  dry  season  they  had 
remarkable  plantations  of  Hevea,  but  they  were  in  localities  which 
were  wet,  or  were  near  a  river,  or  had  water  at  their  side.  They 
had  Hevea  in  Togo,  which  had  a  long  dry  season,  but  it  was  only 
to  be  formd  in  localities  which  had  more  rain  generally  than  others. 
Warburg  beheves  that  it  would  be  easy  to  procure  Hevea  seeds 
which  could  be  cultivated  in  countries  where  the  seasons  were 
partly  wet  and  partly  dry,  but  does  not  give  meteorological 
details.  In  support  of  his  contention  is  the  statement  of  Johnson 
that  he  has  seen  the  foliage  of  Hevea  trees  in  East  and  West 
Africa  quite  fresh  and  green  when  coffee,  cacao,  and  other  plants 
were  drooping  and  losing  their  leaves  on  account  of  the  drought. 
He  further  reports  that  in  East  Africa  he  is  trying  to  cultivate 
Hevea  in  a  very  dry  climate,  but  is  relying  on  a  system  of  irrigation 
for  the  necessary  moisture.  It  is  well-known  that  even  in  Ceylon 
Hevea  trees  can,  without  any  bad  effects,  pass  through  a  rainless 
period  of  a  few  weeks  duration.  It  is,  however,  generally  advisable 
to  select  districts  with  a  rainfall,  temperature,  and  humidity 
somewhat  similar  to  those  in  the  Amazon  valley. 

Speaking  generally,  and  excepting  a  few  well-favoured 
localities  with  sufficient  rainfall,  British  East  Africa  is  not  suitable 
for  Hevea. 

Climate   in    Uganda. 

Owing  to  the  encouraging  results  so  far  obtained  in  Uganda 
it  is  necessary  to  draw  attention  to  the  climatic  factors  ruling 
there. 

The  average  annual  rainfall  for  nine  years  at  Entebbe  is  given 
at  57'98  inches.  It  is  somewhat  different  in  other  parts  of  the 
Protectorate  :  thus  in  1909  the  heaviest  fall  was  at  Mbarasa, 
75 '83  inches  in  104  days. 

The  maximum  temperature  at  Entebbe  is  86.5°F.,  and  at 
Jinja,  90°F.  ;  the  minimum  temperature  at  Entebbe,  55°F.,  and 
kt  Jinja,  58°F. 

Climate  in  the  West  Indies. 

It  is  a  most  remarkable  fact  that  the  West  Indian  islands, 
many  of  which  are  well  within  the  Hevea  rubber  zone,  have  not 
taken  a  very  active  interest  in  this  cultivation.  A  few  old  trees 
occur  on  some  of  the  islands,  and  seeds  are  being  applied  for  only 
in  fair  quantities. 

At  the  Botanic  Gardens,  Trinidad,  during  the  years  1887  to 
1899  inclusive,  the  average  annual  rainfall  was  68.19  inches, 
which  is  lower  than  that  at  Peradeniya,  the  highest  rainfall  in  any 
year  being  92-49  inches  and  the  lowest  46-76.     The  average  mean 


76 


PARA     RUBBER 


annual  relative  humidity  was  78-00,  the  highest  in  any  year- 
being  80-00,  and  the  lowest  75  00.  The  average  mean  annual 
temperature  was  78-54°  F.,  the  highest  79-4,  and  the  lowest 
77-4.     The  mean  minimum  temperature  was  69-57°  F. 

At  Springbank,  St.  Patrick's,  Grenada,  where  the  monthly 
rainfall  in  Grenada  in  1903  most  resembled  that  of  Ceylon,  it  was 
from  January  to  December  :  6-69,  2-00,  1-32,  1-34,  5-27.  8-68, 
10.13,  21.52,  11-42,  II.I9,  5-02,  and  11.52  inches,  the  total  96.10 
inches.  The  total  in  1902  was  66-io  inches.  In  the  years  1903 
and  1904  at  Belvidere,  St.  John's,  it  was  168-20  inches  and  151-29 
inches  respectively ;  at  Dougaldston,  St.  John's,  it  was  107-12 
and  102-34  inches  respectively  ;  at  DunfermUne,  St.  Andrew's, 
82.13  and  70-89  inches  ;  at  Les  Avocats,  St.  David's,  126-19  and 
100-57  inches  ;  at  Annandale,  St.  George's,  150-20  and  136-27 
inches.  These  are  all  cacao-growing  districts  and,  therefore, 
probably  rubber-growing  districts. 

In  Jamaica,  the  average  rainfall  in  1904  at  138  stations  was 
87-99  inches.  In  the  North-East  Division  the  average  monthly 
rainfall  from  January  to  December  was  :  5-88,  8-45,  6-07,  4-11, 
6-91,  18-27,  5-71.  7-02,  5-66,  19.38,  17-81,  and  6.85  inches,  the 
total  112-12  inches.  In  the  North  Division  the  average  total 
annual  rainfall  was  63-72  inches,  in  the  West  Central  Division 
104-40  inches,  and  in  the  Southern  Division,  72.35  inches. 

Jamaica  possesses  plants  of  an  indigenous  rubber  vine — 
Forsteronia  floribunda,  Dc,  but  so  far  does  not  appear  to  have 
taken  an  active  interest  in  Hevea  rubber  cultivation,  though 
saplings  of  this  species  are  reported  to  be  in  a  thriving  condition. 

According  to  W.  Harris,  there  are  many  districts  in  Jamaica 
suitable  for  Hevea  brasiliensis ,  namely : — ' '  Portions  of  St. 
Andrew,  St.  Thomas-in-the-East,  the  lower  lands  in  Portland,  St. 
Mary,  St.  Ann,  St.  Catharine,  Upper  Clarendon,  Manchester,  St. 
Elizabeth,  Trelawny,  St.  James,  Hanover  and  Westmoreland." 
But  later  information  is  to  the  effect  that  Jamaica  is  quite 
unsuitable. 

Climate  in  British  Guiana. 

Looking  to  the  facts  that  Guiana  is  so  close  to  the  home  of 
Hevea  brasiliensis,  and  that  it  is  the  home  of  other  Hevea  species, 
one  is  not  surprised  to  learn  that  its  cultivation  there  is  being 
anxiously  considered.  And  yet,  though  the  rainfall  is  on  the 
average  fairly  well  distributed  throughout  the  year,  there  is  some 
liability  to  years  of  only  moderate  rainfall  : — 

Observations  made  at  the  Botanic  Gardens,  Georgetown. 


Mean 

Average 

Mean 

Average 

temperature, 

Rainfall, 

temperature. 

RainfaU. 

1909. 

1880-1908, 
ins. 

1909. 

1880-1908, 
ins. 

January 

78-8 

856 

August 

88-1 

6-03 

February 

78-7 

670 

September 

798 

306 

March 

794 

7-27 

October 

81  0 

3-09 

April 

8o-2 

7-22 

November 

8i-6 

5'57 

May 

8o-o 

1 1  60 

December 

79-4 

11-84 

June 

79-6 

1172 

July 

79-5 

1044 

Annual 

80.5 

92.84 

PARA     RUBBER 


n 


In  the  three  coastal  districts  the  average  annual  rainfall 
during  the  period  1899-1908,  was  respectively  90-94  inches, 
9273  inches,  and  90*35  inches.  At  the  inland  stations  in  1908 
the  average  annual  rainfall  was  I20'82  inches,  and  no  station 
showed  a  lower  record  than  90  inches.  The  temperature  very 
seldom  falls  below  70°F.  at  Georgetown.  Apparently  the  strong 
winds  at  the  coast  interfere  with  growth. 

Climate  in  Surinam. 

The  rainfall  in  Dutch  Guiana  is  given  as  averaging  90  inches, 
well  distributed  throughout  the  year. 

Preuss  states  that  the  climate  in  Surinam  (Theobroma 
cacao,  Wright)  can  be  divided  into  two  dry  and  two  wet  sejisons, 
the  annual  rainfall  averaging  between  88  and  92  inches  (2,200  to 
2,300  min.).  The  first  little  dry  season  commences  towards  the 
end  of  February,  and  continues  till  the  end  of  May,  the  great 
rainy  season  then  setting  in  and  lasting  until  the  end  of  August. 
The  great  dry  season  follows,  and  drought  conditions  prevail 
until  the  end  of  November,  when  the  second  little  rainy  season 
commences  and  continues  until  the  end  of  Febniary. 


CHAPTER    V. 

RATE     OF     GROWTH     OF     HEVEA     BRASILIENSIS. 

The  rate  of  growth  depends  upon  the  nature  of  the  soil  and 
chmate  and  the  care  which  has  been  exercised  in  selecting  seed 
parents  and  in  planting  operations.  In  districts  having  a  rainfall 
of  about  100  inches  per  year,  an  average  mean  annual  temperature 
of  80°  F.,  and  soil  of  medium  quality,  the  trees  will  grow  about  six 
to  ten  feet  in  height  every  year  for  the  first  three  or  four  years  and 
attain  a  height  of  80  to  90  feet  within  thirty  years. 

Rate  of  Growth  of  Stem. 

The  growth  in  circumference  is  by  no  means  slow  ;  trees  one 
year  old  from  planting  may  have  a  circumference  of  three  to  four 
inches,  and  they  usually  increase  at  the  rate  of  four  to  five  inches 
each  year  for  the  first  few  years  when  planted  as  a  single  product. 
During  the  first  few  years  the  growth  is  mainly  in  length,  and  the 
rapid  increase  in  girth  is  most  noticeable  after  the  trees  are  a  few 
years  old.  The  following  table  shows  the  dimensions  of  trees  of 
known  ages  at  Henaratgoda  ;  the  stumps  were  about  one  year  old 
when  planted. 

Henaratgoda  Trees  planted  in  1876. 


Girth  at  3ft. 

Girth  at  3ft^ 

Year. 

Age. 

Inches. 

Year. 

Age. 

Inches. 

1878 

3 

14 

1887 

12 

53i 

1880 

5 

16 

1888 

13 

60 

18S1 

6 

21 

1889 

14 

69I 

1882 

7 

25i 

1890 

15 

73 

1883 

8 

30 

1892 

17 

77 

1884 

9 

36 

1893 

l8 

79i 

1885 

ro 

43 

1905 

30 

logl 

1886 

II 

m 

Peradeniya  Trees 

Planted 

IN    1876 

Hevea  rubber  trees  were  planted  at  Peradeniya  in  the  South 
Garden  near  the  river  banks,  above  flood-level.  They  were 
planted  10  feet  apart,  probably  in  1876,  when  the  stumps  were 
about  one  year  old,  and  the  following  were  the  dimensions  of  the 
trees  in  June,  1905  : — 


Height. 

Girth  at  3ft. 

Height. 

Girth  at  3ft. 

No.  of  Tree. 

ft.  in. 

Inches. 

No 

.  of  Tree. 

ft.  in. 

Inches. 

I 

51     7 

44 

7 

78     7 

58 

2 

89     6 

82 

8 

79     3 

56 

3 

73     3 

52 

9 

89     5 

81 

4 

82     7 

59 

10 

76     2 

50 

5 

84     2 

59 

II 

74     3 

43 

6 

55     4 

49 

PARA     RUBBER  79 

The  following  list  gives  the  dimensions  of  the  trees  planted  in 
1881  along  the  river  bank,  where  they  are  liable  to  be  flooded  when 
the  water  is  high.  They  are  remarkable  on  account  of  the  growth 
obtained  when  planted  so  close,  the  average  distance  between  the 
trees  at  the  present  time  being  9  to  10  feet. 


Circumference, 

Height. 

Circumference, 

Height 

3ft.  from  Base. 

3ft.  from  Base. 

Tree. 

ft.     in. 

ft. 

in. 

Tree. 

ft.     in. 

ft.  in. 

I 

4       9 

57 

2 

8 

■3       7 

79     6 

2 

4       2 

87 

4 

9 

5       3 

84     2 

3 

4       3 

61 

7 

10 

4     10 

86     I 

4 

6     iij 

82 

3 

II 

5       5 

67     4 

5 

6       8 

89 

I 

12 

5       8 

78     9 

6 

4       5 

81 

5 

13 

5       9 

64     7 

7 

2       9 

52 

7 

Other  measurements  show  that  at  Edangoda  and  Yattipawa, 
trees  two  years  old  girthed  4"96  inches,  those  three  years,  875  to 
9-37  inches,  and  the  four-year-old,  12-96  inches  a  yard  from  the 
ground. 

Rate  of  Growth  in  Other  Parts  of  Ceylon. 

The  following  figures  show  the  dimensions  of  Hevea  rubber 
trees,  interplanted  with  tea  and  cacao,  in  Ceylon  : — 

Circumference  of  the  Stem  in  Inches,  3  Feet  from  the  Base. 
Age  of 

Trees  in  Sahara-  Katugas- 

years.  Kegalla.  Knuckles,  gamuwa.  tota. 

2  —  5  —            — 

3  —  — 

4  —  14-16 

5  21  to  30J        — 

6  —  — 

7  —  — 

8  —  — 

—        15*046 

In  districts  over  2,000  feet  above  sea-level,  or  where  the  rubber 
has  been  planted  in  inferior  or  unsuitable  soils,  the  growth  is  much 
poorer.  On  one  estate  near  Peradeniya,  2,200  feet  above  sea-level, 
9-year-old  trees  only  measured  24  to  46  feet  in  height  and  15  to  46 
inches  in  circumference  a  yard  from  the  ground  ;  the  following 
dimensions  of  the  trees  referred  to  will  be  of  interest  to  those 
planters  who  are  trying  Hevea  rubber  at  high  elevations  in  Ceylon 
and  elsewhere  : — 


14 



15 



21 



274 

19 

31 



314 

24 

65 

38 

Pera- 

Kalu- 

deniya.  Nilamhe. 

tara. 

2  to  6           — 

5 

10            — 

9 

—            — 

17  to  20 

Length  of 

Spread  in 

Circumference 

No.  of 

Trunk. 

Widest  Part. 

3  Feet  from  the  Base. 

Tree. 

ft. 

in. 

ft. 

in. 

in. 

I 

42 

0 

29 

8 

46 

2 

36 

0 

21 

0 

22i 

3 

34 

6 

13 

0 

154 

4 

46 

10 

22 

6 

24 

5 

42 

6 

22 

8 

22 

6 

32 

5 

18 

0 

a2i 

7 

36 

6 

17 

0 

254 

8 

46 

8 

25 

6 

a 

1^ 

24 

4 

13 

4 

17 

10 

42 

8 

29 

0 

35 

8o  PARA    RUBBER. 

In  other  districts  where  the  rubber  has  been  planted  in  very 
poor  tea  and  cacao  land  the  growth  is  often  very  slow. 

Upon  an  estate  in  the  AUagalla  district,  where  the  rubber  has 
been  planted  in  cacao  on  weedy  land,  growth  has  been  slow.    Trees 

5  years  old,  between  12  and  20  inches  girth,  number  476  ;  between 

6  and  12  inches,  8,186  ;  under  6  inches,  21,596.  Four-year-old 
trees  between  10  and  12  inches  number  1,197  '■  between  6  and  8 
inches,  19 ;  under  6  inches,  3,238.  The  three-year-old  trees 
between  6  and  8  inches  number  76  ;   under  6  inches,  3,535- 

Upon  a  very  rocky,  poor  soil  in  the  Tumpane  district,  supply- 
ing has  been  frequently  done.  Trees  from  4^  to  4f  years  old  fall 
under  the  following  measurements  :  18  to  30  inches,  1,996  ;  10  to 
18  inches,  18,501  ;  under  10  inches,  13,062.  The  measurements  and 
numbers  of  those  from  3^  to  3f  years  old  are  :  15  to  30  inches, 
483  ;    10  to  15  inches,  9,699  ;    under  10  inches,  19,129. 

The  Hewagam  Rubber  Co.  reported,  in  1910,  an  average 
increase  in  girth  at  the  rate  of  fully  four  inches  per  annum. 

The  Neboda  Tea  Co.,  in  their  annual  report  for  1905,  state 
that  "the  1904  clearings  range  from  17  to  27J  feet  in  height  and 
from  6  to  10  inches  in  circumference,  while  last  year's  basket  plants, 
put  out  in  April-May,  from  August,  1904  seed,  show  the  best 
growth  :  8|  to  I2|  feet  in  height  and  3^  to  4^  inches  in  girth. 

At  Gangaruwa,  1,500  feet  above  sea-level,  trees  3^  years  old 
averaged  10  inches  at  a  yard  from  the  ground.  These  trees, 
planted  by  me  in  1905,  were  reported  to  show  an  average  increase 
in  girth,  from  December,  1908,  to  January,  1910,  of  5  29  inches  ; 
the  minimum  girth  (4-94  inches)  was  on  a  plot  which  was  inter- 
planted  with  lemon  grass,  and  the  maximum  (5 -81  inches)  on  land 
catch-cropped  with  indigo. 

Growth    on  Vogan   Estate. 

I  have  been  favoured  with  details,  by  Mr.  W.  N.  Tisdall, 
indicating  the  growth  of  the  Hevea  rubber  trees  on  Vogan  Estate, 
Kalutara,  Ceylon.  The  trees  were  planted  in  July,  1904,  and 
measured  in  March,  1906  (twenty  months'  growth),  5-88  inches 
average  circumference  at  three  feet  from  the  base  ;  nine  months 
after  (December,  1906),  the  girths  had  increased  3-64  inches,  the 
average  then  being  9-52  inches ;  October  29th,  1907,  the  average 
circumference  was  13-60  inches.  These  measurements  show 
that  twenty  months  after  planting  the  trees  measured  5-88  inches, 
and  in  the  following  ij  years  the  increase  was  772  inches,  or  at  the 
rate  of  5  inches  per  annum. 

Census    of    Estates. 

The  following  examples  will  serve  to  indicate  the  manner  in 
which  the  census  of  estates  may  be  shown. 


PARA     RUBBER  8i 

Hanipha    (Ceylon)    Tea   and    Rubber   Co. 
Census  of  Para  Rubber  Trees  taken  as  on  31ST  December,  1909. 


i8in.  & 
over.  , 

15  in.  to 
17  in. 

12  in.  to 
14  in. 

9  in.  to 
iiin. 

6  in.  to 
Sin. 

Young 
Plants. 

Total. 

3,703            4,677          11,273 
All  measurement's  taken 

.  at  3  feet  from  the  gi 

18,729        67,011 
ound.     Of  this  total 

26,810  Trees  are  planted  among  the  Tea,  and 
40,201        „  „      in  separate  clearings. 

Pantiya    Tea    and    Rubber    Co. 
Rubber  Census  November,  1910. 


Tapping. 

18  in.  up- 
wards. 

15-18 
in. 

12-15 

in. 

9-12 
in. 

6-9 
in. 

Under  6 
in. 

Total. 

23,300 

1,031 

7.957 

15,201 

18.955 

19,816 

68,293 

154.553 

Ceylon   Tea   Plantations   Co. 

Approximate    Census    or   Rubber    Trees,    at    December,  igio. 

Girth  in  inches.     Over  18    15  to  18      12  to  15       9  to  12      Below  9      Totals. 
In  Tea     ..  ..     60,510      39,966       58,597         85,417      142,469     386,959 

In  Clearings        ..     42,450      43,495       68.096        117,888     127,795     399,724 


Totals  . .    102,960     83,461       126,693      203,305      270,264      786,683 

Ceylon    (Para)    Rubber   Company. 

The  census  of  the  trees  taken  towards  the  end  of  December, 
1910,  vs^orks  out  as  follows  : — 

18  in.  Under 

and  over.  15-18  in.  12-15  in.  9-12  in.        gin.  Total. 

Ambadeniya         37,260        30,720         32,275  25,295        54,199  179,749 

Kiribatgalla          47.356        40,175         47.876  46,224  140,269  321,900 

84,616        70,895         80,151        71,519      194,468       501,649 
These  figures  compare  with  the  previous  year's  as  follows  :  — 

l8  in.  Under 

and  over    15-18  in.    12-15  in.      9-12  in.        gin.         Total. 
13,664        29,703        65,257        96,575      275,698    480,897 

Rate  of  Growth  in  India  and  Burmah. 

Proudlock  when  reporting  (1908)  on  rubber  trees  at  Nilambur, 
gave  the  following  statistics  regarding  trees  planted  in  June,  1879, 
and  measured  in  April,  1884  : — 

Height.    Girth  at  Base.    Girth  at  5ft.  up. 

ft.  ins.  ins. 

38  19  Hi 

37  20  12 

33i  i9i  i2i 

34  194  12 

34  19  9i 


82  PARA    RUBBER 

These  figures  are  only  interesting  in  so  far  as  they  show  the 
proportionate  development  of  parts  of  trees  which  had  been 
neglected. 

The  growth  on  estates  in  S.  India,  at  low  elevations,  is  quite 
good.  Six  trees  owned  by  the  Cochin  Rubber  Co.,  planted  in 
1906,  measured  4f  inches,  at  three  feet  from  the  ground,  in 
December,  1907,  and  8J  inches  in  December,  1908.  Kirk,  of  the 
Periyar  Rubber  Co.  (Planters'  Chronicle,  June,  1910),  refers  to 
Vincent's  deduction  that  the  difference  in  inches  between  measure- 
ments made  at  the  base  and  three  feet  from  the  ground  gives  the 
approximate  annual  increase  in  girth  ;  his  own  trees  give  the 
difference  in  girth  at  from  4  to  8  inches,  which  is  in  general  accord 
with  his  average  annual  increase  in  girth.  This  is  certainly  not 
characteristic  of  trees  in  Malaya  ;  bottle-shaped  trunks  are  often 
met  with  but  generally  only  on  poor  or  interplanted  land. 

In  many  parts  of  Southern  India,  Hevea  rubber  is  being 
more  or  less  successfully  grown  up  to  3,500  feet  above  sea-level. 
Trees  at  an  elevation  of  2,500  feet  have  attained  a  height  of  18  feet 
in  three  years,  a  circumference  of  42  inches  in  17  years,  and  nearly 
60  inches  in  22  years. 

On  the  Shevaroy  Hills,  at  an  elevation  of  3,400  feet,  Hevea 
rubber  trees  are  reported  to  be  about  10  inches  in  circumference 
when  three  years  old  ;  others  are  reported  at  3,600  feet  in  the 
Nilgiris  and  the  Anamallais  to  be  from  9  to  13  inches  in  circum- 
ference and  19  to  29  feet  in  height,  when  three-and-a-half  years 
old.  On  many  of  these  properties  the  rubber  is  used  as  shade  for 
coffee,  and  from  all  accounts  the  latter  is  thriving  under  the  shade 
of  Hevea  and  Castilloa  rubber. 

The  Hevea  rubber  trees  in  some  parts  of  South  India  do  not 
appear  to  increase  much  more  than  3  to  4  inches  in  circumference 
per  year,  and  a  girth  of  20  inches  in  5  years  would  be  considered 
satisfactory. 

The  following  figures  showing  the  dimensions  of  nine-year-old 
trees  in  Mergui  (girths  being  taken  at  2  feet  above  ground),  have 
been  given  by  Colonel  W.  J.  Seaton  : — 

Girth  in  Girth  in 


No. 

Height  in 

Feet. 

Inches. 

No. 

Height  in  Feet. 

Inches. 

I 

39 

29i 

6 

38i 

27i 

a 

34i 

37 

7 

36i 

31 

3 

40 

38 

8 

30 

18 

4 

43i 

4oi 

9 

31 

27 

5 

36J 

39i 

10 

21J 

i8i 

Rate   of   Growth   in    Malaya. 
The  growth  in  most  parts  of  the  Straits  Settlements  and 
Federated  Malay  States  is  considered  to  be  very  encouraging  and 
superior  to  that  obtained  in  many  other  rubber-growing  countries. 

Growth   in   Singapore. 
There  are  many  trees  in  Singapore  Gardens,  planted  6  and 
8  feet  apart,  over  15  years  old,  with  girths  from  50  to  70  inches 


PARA     RUBBER  83 

and  over.  They  are  planted  in  isolated  clumps  and  are  not  under 
the  conditions  prevailing  on  rubber  estates. 

The  record  tree  at  Singapore  was,  in  1908,  though  only  54  feet 
in  height,  no  less  than  120  inches  in  girth  at  a  yard  from  the 
ground.  It  was  then  30  years  old,  and  I  believe  was  the  largest, 
in  circumference,  recorded  up  to  that  time. 

The  seven  trees  received  in  1877,  were  first  planted  in  the 
Botanic  Gardens  by  Murton,  and  on  the  founding  of  the  Economic 
Gardens  in  1880  by  Cantley  were  transferred  to  their  present 
position.  One  tree  was  evidently  topped  at  about  four  feet  from 
the  ground  and  then  threw  out  three  branches,  which  are  now 
very  large.  It  is  growing  in  the  open  low  swampy  soil.  It  gave 
fourteen  pounds  of  rubber  on  being  tapped  by  the  spiral  system, 
and  would  probably  have  given  more  under  any  other  system 
of  tapping. 

The  growth  in  girth  of  this  tree  in  the  last  few  years  has 
been  :  1904,  109J  inches  ;  1905,  iiif  inches  ;  1906,  113!  inches  ; 
1908,  120  inches. 

Derry  recorded  the  girths  of  trees  of  from  3  to  18  years  ; 
the  average  for  three  years  being  13  to  15  inches,  and  for  18 
years,  100  inches. 

Rate  of  Growth  in  Selangor. 

The  following  measurements  of  trees  in  Selangor  of  known 
age  and  planted  at  definite  distances  apart  were  made  by  me  in 
1908  : — 

^  "  Girths  in  inches,  a  yard  from  ground,  ot 

trees  in  one  line. 

3i    2i,    2j,    2|     2|,    2f,    2f,    i| 
2j,    3i.    2f,    2i,    Ij,    2f 

7,  6,  7,  6,  6,  5,  7,  4,   7,  5 

17,  7,   II,   13,   14,    II,   13,  7,    14,   14,   17 
14,   16,   18,   10,   12,    17,  20,   12,   14,   14,   18" 
16,    19,   12,   17,   12,   14,   16,   15,   12,  9,   15 

18,  14,  9,   14,    II,   15,   14,   12,  9,   II 

The  growth  in  girth  during  the  third  year  on  these  estates 
was  rapid  ;  the  same  feature  was  observed  on  many  other  properties. 

On  another  estate  in  the  same  district,  on  which  lalang  had 
established  itself,  18  per  cent,  of  the  trees  measured  20  inches,  a 
yard  from  the  ground,  when  3f  years  old,  a  large  number  of  the 
balance  being  15  inches  in  girth. 

Trees  on  an  estate  in  Selangor  grew  to  a  height  of  over  30  feet 
and  attained  a  girth  of  19  inches  in  4  years. 

Growth  on  Jeram  Estate. 

On  Jeram  Estate,  Klang,  the  following  girths  of  trees  of 
different  ages  taken  at  random  have  been  issued  : — 

Age.  Girth,  in  inches,   3  feet  from  ground. 

5j  years.  19,  26^,  21J,  28J,  27J,  2of,  25J,  26,  32,  24^.  26f,  28^, 

29J,  17,  i8i,  25f,  27J,  20^,  27f,  2oj,  27f,  14J 


Distance 

apart  in 

Age. 

feet 

8  months 

24  by   12 

9       „ 

24  ,,     12 

10       ,, 

— 

2  years,    8  months 

— 

2        „       9       , 

— 

3  years 

17  by   17 

3  years 

20  ,,     10 

&t  PARA    RUBBER 

Age.  Girth,  in  inches,  3  feet  from  ground. 

5  years.  27^,  23J,  iSJ,  24^,  27^,  17I,  17!,  26J,  21J,  15I,  2oi,  igj, 

13,  i7i,  16,  16J,  26^,  i3f,  I2|,  I4i  15.  15.  iif.  i8|- 
4f  years.  22J,  2if,  23!,  24J,  15?,  22|,  23,  20,  23,  2o|,  28J,  19I, 

24i.  25- 
4  years  (lalang).        13J,  isj,  13!,  15I,  12J,  17!,  i8|,  12J,  14^,  i5if,  15.  20*- 

4  years  (passion        2i|,  13^,  21^,  20^,  16J,  23,  igj,  i2f,  24!,  17^,  19,  I3t- 
flower). 

The  above  figures  are  of  special  interest  because  the  trees 
have  been  grown  under  known  conditions. 

The  51  year-old  block  was  always  kept  clean  weeded. 

The  5-year-old  trees  were  all  under  lalang  until  18  months 
ago. 

The  4|-year-old  trees  were  under  passion  flower  for  12 
months. 

The  first  series  of  4-year-old  trees  was  under  lalang  up  to 
18  months  ago  ;  the  second  group  was  under  passion  flower  until 
18  months  ago. 

Growth  in  Perak. 

In  Perak  are  ii-year-old  specimens  that  are  70-75  feet  high, 
and  have  a  mean  girth  of  4^  feet  at  3  feet  from  the  ground,  and 
a  lo-year-old  tree  that  is  79  feet  high  and  girthing  4^  feet. 

At  Kuala  Kangsar  an  18-year-old  tree  has  a  girth  of  8^  feet 
at  3  feet. 

Sutton  stated  last  year  at  the  annual  meeting  of  the  Allagar 
Rubber  Estates,  that  3^  to  4-year-old  trees  interplanted  with 
coffee  had  a  girth  of  21  to  37  inches  ;  others  rising  4  years  measured 
22  to  30  inches  ;  those  rising  5  years  girthed  23  to  33  inches  ; 
and  a  number  rising  6  years  measured  27  to  50  inches.  Ten- 
year-old  trees  on  the  same  property  girthed  from  55  to  63  inches, 
all  at  3  feet  from  the  ground. 

Growth  in  Malacca. 

There  is  a  general  impression  that  growth  in  Malacca  is 
much  slower  than  in  other  parts  of  Malaya,  on  account  of  poor 
soil  or  the  cultivation  of  catch  crops.  It  is  frequently  found  that 
three  or  four  crops  of  tapioca  are  taken  by  native  cultivators  from 
the  same  area.  In  one  case  where  four  crops  of  tapioca  had 
been  taken  and  the  Hevea  trees  were  4  years  old,  the  latter  only 
girthed  9  to  12|  inches  a  yard  from  the  ground  ;    a  range  of  from 

5  to  7  inches  and  14  to  15  inches  has  also  been  recorded  for 
4-year-old  Hevea  on  land  from  which  three  crops  of  tapioca  had 
been  removed. 

Growth  in  Other  Parts  of  Malaya. 
On  some  estates  it  is  nc3t  uncommon  to  find  four-year-old 
Hevea  trees  from  14  to  20  inches,  and  4|-year-old  specimens 
averaging  over  20  inches  a  yard  from  the  ground.  On  one  pro- 
perty, catch-cropped  annually  with  sugar  canes,  the  2 1 -year-old 
trees  had  an  average  of  8  to  9  inches,  the  largest  being  14  inches 
in  circumference. 


PARA     RUBBER  85 

Phenomenal  growth  in  some  parts  of  the  Straits  is  often  met 
with,  trees  18  months  old  being  sometimes  nearly  30  feet  high, 
and  trees  8  years  old  having  a  circumference  of  45  or  more  inches 
a  yard  from  the  ground. 

The  5-year-old  trees  upon  a  Province  Wellesley  estate  have 
the  following  girth :  between  15  and  18  inches,  964  trees ; 
between  12  and  15  inches,  9,107  trees  ;  between  10  and  12,  7,327 
trees. 

Killick  (Financier,  Sept.,  1911),  reported  that  some  trees  in 
Kelantan,  2|-years-old,  measured  15,  17,  18,  i8|  inches,  even 
though  they  had  been  in  lalang  for  six  months.  On  Taku  Estate 
he  saw  trees  which,  in  his  opinion,  should  be  tappable  at  3  years 
of  age. 

Growth  in  Java. 

Detailed  statistics  showing  the  average  sizes  of  trees  of  known 
ages  in  that  island  are  not  available.  Many  parts  of  Java  are 
relatively  dry,  and  in  such  the  Hevea  rubber  plants  have  not 
developed  very  rapidly ;  in  other  districts,  provided  with  an 
abundant  rainfall,  the  growth  is  reported  to  be  quite  equal  to  that 
in  most  parts  of  Ceylon. 

During  the  course  of  my  recent  visit  to  Java,  I  found  that 
in  a  few  instances  the  growth  of  Hevea  was  second  to  none.  But 
on  most  of  the  estates  I  visited,  the  growth  was  not  what  I 
expected  it  to  be  from  considerations  of  the  climatic  and  soil  con- 
ditions prevailing.  The  less  rapid  growth  can,  I  believe,  be 
partly  explained  by  the  .intercropping,  absence  of  drains,  and 
prevalence  of  weeds,  which  characterise  the  properties  I  refer  to. 
The  system  adopted  is  a  very  safe  one,  and  is  sometimes  cheap  ; 
but  it  does  not  allow  the  trees  to  develop  as  rapidly  as  they  might 
do  in  such  ideal  soil.  When  one  has  a  soil  on  which  coconuts 
can  be  brought  to  the  productive  stage  in  five  years,  and  tea 
crops  average  800  lb.  per  annum,  one  has  some  gr.)und  for 
expecting  the  Hevea  trees  to  grow  at  the  rate  of  six  inches  in  girth 
per  annum.  I  was  shown  some  trees,  reputed  to  be  five  year ,  old, 
which  girthed  32  inches.  Such  growth  should  be  the  rule,  and 
not  the  exception,  in  Java.  Trees  planted  at  Binangoen  in  1907 
showed  at  the  end  of  1910  the  following  girths  a  yard  from  the 
ground: — I5in.  to  I7in.,  8,979  trees;  i7in.  to  i9in.,  3,964  trees; 
19  inches  and  over,  1,323  trees.  Three-year-old  trees  on  this 
estate  measured  16,  i6|,  17,  and  18  inches  a  yard  from  the  ground. 
On  another  estate  in  East  Java,  interplanted  with  robusta  coffee 
and  "Lamtoro"  shade,  the  3-year  old  Hevea  trees  averaged 
from  8  to  12  inches  in  girth  ;  another  field  of  the  same  age  possessed 
trees  of  from  7  to  11  inches.  Two-year-old  Hevea  on  the  same 
estate  measured  5^  to  7J  inches  in  girth,  a  yard  from  the  ground. 

A  census  of  3^  to  4j-year-old  trees  on  another  East  Java 
estate  showed  that  there  were  7  per  cent,  with  a  girth  of  between 
15  and  18  inches  ;  13  per  cent,  between  10  and  12  inches  ;  40  per 
cent,  between  8  and  10  inches  ;  31  per  cent,  between  6  and  8 
inches  ;    and  under  6  inches  there  were  9  per  cent.     The  girths  of 


86  PARA     RUBBER 

2i  to  3i-year-old  trees  were  :  between  15  and  18  inches,  3  per 
cent.  ;  between  10  and  12  inches,  9-5  per  cent  between  8  and 
10  inches,  37-5  per  cent.  ;  between  6  and  8  inches,  36  per  cent.  ; 
and  under  6  inches,  14  per  cent. 

Upon  a  West  Java  estate,  trees  4  to  5  years  old  girthed  : 
between  18  and  30  inches,  1,437  ;  Isetween  10  and  18  inches, 
13,242  ;  under  10  inches,  14,661.  This  was  on  weedy  land,  where 
supplying  had  been  heavy. 

The  manager  of  Sampang  Peundeni  estate  has  suppUed  me 
with  the  measurements  of  trees  on  his  estate.  These  show  an 
average  girth  of  19-88  inches  for  50  trees  at  4  years  ;  the  trees 
were  growing  at  an  altitude  of  700  feet  where  the  annual  rainfall 
was  approximately  140  inches. 

Four-year-old  trees  on  another  property,  planted  14  by  14 
feet,  show  an  average  circumference  a  yard  from  the  ground  of 
from  7  to  20  inches.  Others  planted  12  by  12  feet  show  an  average 
girth  of  from  6  to  13  inches.  Other  four-year-old  trees  not  far 
removed  from  the  foregoing  had  a  girth  of  from  6  to  13  inches. 
These  were  planted  20  by  20  feet  apart  in  virgin  land,  and  the 
estate  had  been  kept  clean  from  the  commencement.  On  the 
same  estate,  though  the  trees  were  of  the  same  age  and  planted 
at  the  same  distance,  but  on  old  coffee  land  and  only  circle-weeded, 
the  girth  varied  from  5  to  8  inches. 

Rate  of  Growth  in  Sumatra. 

Most  people  have  the  idea  that  phenomenally  rapid  growth 
is  to  be  seen  in  Sumatra,  the  Hevea  trees  being  reputed  to  increase 
in  girth  at  the  rate  of  six  inches  per  year.  I  have  certainly  seen 
trees  which  have  grown  at  that  rate  when  planted  alone  and  on 
virgin  land,  but  most  estates  I  visited  could  not  generally  lay  claim 
to  such  rapid  developments.  The  well-known  Sumatra  rubber 
estates  have  nearly  all  been  developed  out  of  coffee  plantations, 
and  the  growth  of  the  trees  thereon  is  not  what  it  might  otherwise 
have  been.  Coffee  bushes,  especially  when  old,  do  keep  back  the 
growth  of  Hevea  trees.  The  growth  of  the  trees  is  most  rapid 
when  planted  alone,  next  best  when  planted  at  the  same  time  as 
the  intercrop,  and  slowest  when  in  old  coffee  or  on  old  lalang 
and  tobacco  grounds.  I  should  put  the  circumferential  rate  of 
growth  in  Sumatra  at  six,  five,  and  four  inches  respectively,  on 
lands  included  in  the  three  categories  enumerated  above.  It  is 
very  dangerous  to  generahse  in  this  way,  especially  when  the  trees 
are  scattered  over  the  Serdang,  Langkat,  Bandar,  and  Asahan 
districts,  but  I  think  the  above  conclusion  will  be  found  to  be 
approximately  correct  in  most  instances. 

It  has  recently  been  stated  by  Mr.  J.  B.  Laurent  that  Hevea 
trees  in  Sumatra  had  measured,  when  three  years  old,  16  inches  ; 
when  four  years  old,  20  inches ;  and  at  five  years,  25  inches  in 
girth. 

The  slower  rate  of  growth  and  smaller  37ield  from  rubber 
trees  in  Sumatra,  when  compared  with  the  F.M.S.,  can  probably 
be  attributed  to  the  soil  conditions  and  to  the  fact  that  many 


PARA     RUBBER  87 

are  planted  between  old  coffee  trees.  On  most  Sumatra — and 
also  Java — Hevea  estates  the  soil  is  volcanic  and  very  dry,  the 
water-level  being  usually  many  yards  below  the  surface.  The  dry 
soil  contrasts  markedly  with  the  wet  soil  of  the  F.M.S.,  and  is  the 
probable  cause  of  the  slower  development  of  the  trees  in  Sumatra, 
especially  during  the  first  four  years.  In  subsequent  years,  when 
the  roots  reach  the  water-level,  the  growth  may  be  very  rapid. 

An  illustration  showing  a  five-year-old  tree  on  Bandar  Sumatra 
estate  with  a  girth  of  38I  inches  is  given  in  the  "  India- Rubber 
Journal,"  September  6th,  1909.  This,  though  in  coffee  land,  is 
exceptional  growth  for  Sumatra,  the  average  being  generally 
below  this. 

Different  trees  in  the  Bandar  district,  when  six  years  old, 
measured  from  22  to  38  inches  a  yard  from  the  ground ;  a  few 
girthed  over  40  inches.  Five-year-old  trees  measured  from  14  to 
28  inches  ;  four-year-old  specimens  ranged  from  12  to  27  inches, 
and  three-year-old  from  9  to  15  inches.  A  large  number  of  these 
were  interplanted  among  Liberian  coffee. 

On  an  estate  in  Langkat  trees  planted  in  1906  measured 
in  the  middle  of  1908,  7,  6,  6,  4,  5,  6,  6|,  and  10  inches  a  yard 
from  the  ground  ;  those  planted  in  1905,  measured  at  the  same 
date,  6J,  7J,  9,  10,  and  12  inches.  These  trees  were  planted  among 
old  coffee  ;  when  planted  alone  a  much  better  rate  of  growth 
was  recorded.  On  another  estate  in  the  same  district  where  the 
soil  was  poor  and  the  Hevea  trees  planted  among  old  coffee,  the 
four-year-old  trees  measured  20,  16,  17,  12,  11,  20,  17,  and  23 
inches;  two-year-old  Hevea  trees  girthed  7I,  6,  10,  11,  and  9 
inches  ;  and  ij-year-old  trees  averaged  6  inches — all  a  yard  from 
the  ground. 

On  an  estate  in  the  Tamiang  district  two-year-old  Hevea 
trees,  planted  alone,  measured  in  one  row  8,  7,  10,  9,  7,  9,  7,  8,  7,  6, 
5  inches ;  during  the  growing  season  many  two-year-old  trees 
increased  their  girth  at  the  rate  of  i  to  i  J  inches  per  month. 

In  the  Siantar  district  I  measured  i|-year-old  trees  which 
girthed,  at  a  yard  from  the  ground,  3  to  5J  inches. 

Growth    in    British    Borneo. 

The  measurements  of  20  Hevea  rubber  trees  on  an  estate 
belonging  to  the  British  Borneo  Para  Rubber  Co.,  Ltd.,  have  been 
received.  Twelve  20-month-old  trees  show  an  average  height 
of  20ft.  8in.  and  a  girth  of  8fin.,  at  3ft.  from  the  ground.  Eight 
trees  17  months  old  show  an  average  growth  of  19ft.  gjin.  in  height 
and  7  J  in  girth. 

The  Tenom  Rubber  Co.,  Ltd.,  reported  in  1908  that  trees 
only  12  months  old  had  an  average  height  of  10  feet.  At  a  later 
period  measurements  were  given  showing  an  average  increase 
in  girth  of  8|  inches  in  two  years  ;  many  trees  appear  to  attain 
a  girth  of  17  to  20  inches  in  four  years. 

"The. North  Borneo  Gazette"  stated,  in  1908,  that :  "One- 
hundred-and-fifty-five   Hevea    rubber  trees  in   the   Government 


88  PARA     RUBBER 

experimental  Gardens  at  Tenom,  were  planted,  not  before 
December,  1900,  nor  after  July,  1902  (exact  date  is  uncertain,  as 
no  records  were  kept).  The  plants  have  been  uncared  for  and 
allowed  to  grow  as  they  liked,  with  the  result  that  about  one 
quarter  of  them  have  two  or  three  stems  ;  this  lowers  considerably 
the  average  girth,  as  in  these  calculations  each  separate  stem  is 
regarded  as  a  separate  tree  ;  even  then  we  get  an  average  girth  at 
five  to  six  and  a  half  years  old  of  21  inches  at  3  feet  from  the 
ground,  and  the  average  increase  in  the  girth  during  the  last  12 
months  (ending  31st  July,  1907)  is  four  and  three-quarter  inches 
(Singapore  Botanic  Garden  records  an  average  of  3^  inches)." 
Since  this  was  published  more  reliable  data  have  been  obtained 
regarding  the  growth  of  Hevea  rubber  in  various  parts  of  Borneo. 
There  is  no  longer  any  doubt  that  the  climate  and  soil  in  parts 
of  Borneo  are  quite  as  suitable  as  in  Malaya  for  the  cultivation  of 
Hevea  brasiliensis. 

Growth  in  Papua  and  Queensland. 

It  is  reported  (T.A.,  April,  1908),  that  trees  at  four  years  of 
age  in  Papua  are  seeding.  This  often  indicates  fair  growth. 
It  is  also  stated  that  Hevea  trees  at  Sogeri,  3-J-  years  old,  have  a 
circumference  of  18  inches  a  yard  from  the  ground. 

Some  10  eight-year-old  trees  at  Kamerunga,  Queensland, 
have  girths  of  from  18  to  24  inches  at  3  feet. 

Growth  in  Fiji,   Hawaii  and  Cochin-China. 

In  the  Fiji  Islands  some  13-month-old  plants  show  (Trop. 
Agr.,  Jan.,  1910)  irregular  growth,  the  best  being  10  feet  high. 
The  average  girth  at  3  feet  of  some  i-year-old  plants  was  4-0 
inches  ;    2-year   plants,  575  inches  ;    3-year  plants,    9-2   inches. 

Hevea  is  making  rather  slow  growth  in  Hawaii. 

In  Indo-China  (Trop.  Agr.,  Jan.,  1910)  some  trees  3  years  and 
10  months  old  were  said  to  have  a  girth  of  15^  inches  ;  whether 
this  was  at  the  base  or  at  3  feet  was  not  stated. 

It  is  stated  by  Vernet  (J.  d'Agr.  Trop.,  July,  1909),  that  the 
trees  at  Suoi-Giao  are  making  fair  growth.  The  mean  girth  of 
93  eight-year-old  trees  at  3  feet  is  25J  inches,  and  of  47  ten-year- 
old  trees  32  inches.  One  may  remark  that  an  average  annual 
increase  of  3J  inches  is  not  good. 

Some  three-year-old  trees  at  Ong-Yem  measured  from  9  to 
gl  inches  in  girth  (J.  d'Agr.  Trop.,  Nov.,  1910),  and  the  average 
of  400  eleven-year-old  trees  was  at  3  feet  only  37!  inches. 

Rate  of  Growth  in  West  Africa. 

Hevea  trees,  planted  on  moist  land  in  the  Congo,  were 
reported  to  be  16  feet  in  height  in  two  years. 

Evans,  in  his  Annual  Report  for  1906,  states  that  in  the 
Axim  and  other  wet  districts  of  West  Africa,  Hevea  brasiliensis 
should  give  handsome  returns  after  a  few  years.  Several  estates 
in  the  Eastern  and  Western  provinces  are  planting  Hevea  rubber 


PARA     RUBBER 


89 


in  conjunction  with  other  products,  and  the  Botanic  Department 
at  Aburi,  Gold  Coast,  supplies  plants  at  reasonable  rates.  Evans 
also  gives  the  following  details  regarding  the  growth  of  Hevea 
rubber  trees  up  to  December,  1908,  at  the  Botanic  Gardens, 
Tarkwa  (average) : — 


Date 

Distance 

Height 

Height 

Girth  at  3  feet  from  ground. 

of 

in 

Dec. 

Dec. 

Dec. 

Dec. 

Dec. 

Dec. 

Planting. 

feet. 

1905. 

1906. 

1905- 

1906. 

1907. 

1908. 

feet 

feet 

inches 

inches 

inches 

inches 

June,    1904 

15  by  15 

20 

28 

7 

12 

13 

20 

,,         ,, 

12  ,,    12 

16 

25 

6 

10 

12 

16 

July     .. 

15..    15 

14 

24 

6 

10 

12 

18.5 

.. 

20  ,,    20 

14 

25 

6 

II 

12 

19 

., 

30..    30 

12 

27 

4 

9 

10 

16 

.< 

40  ,.    40 

12 

27 

4 

9 

10 

16.5 

,,      ,, 

12  ,,    12 

12 

26 

4 

9 

— 



Aug.  to  Sep 

12  ,,    12 

12 

27 

4 

• 
10 

— 

19.2 

In  1909  Tudhope  reported  that  the  trees  planted  in  June 
20th  and  24th,  1904,  had  an  average  girth  of  24  and  22  inches 
respectively. 

Plants  have  been  established  in  the  Botanic  Gardens  (Annual 
Report,  1903),  Aburi,  at  different  dates,  and  most  of  them  have 
made  favourable  growth  (though  planted  in  dry  and  stony 
ground).  Some  of  the  trees  only  18  months  old  were  10  feet  high, 
and  had  stems  3  inches  in  diameter  ;  others  planted  15  by  15  feet 
in  1900  and  1901  measured  an  average  of  20J  inches  at  a  yard 
from  the  ground,  in  1908.  The  trees  planted  in  1901  fruited  in 
1907,  and  according  to  Anderson,  100  per  cent,  of  the  seeds 
germinated.  The  following  table  shows  the  growth  of  certain 
trees  at  different  ages : — 

Aburi  Botanic  Gardens. 


Age  of  trees  in 

Height 

Girth  at  3  feet 

years. 

in  feet. 

in  inches. 

10 

30-25 

27 

12 

36 

40 

4 

23 

10 

6 

29 

I6 

3 

17-5 

6.5 

5 

27 

12 

At  Coomassie,  the  two-year-old  Hevea  plants  average  16 
feet  in  height ;  some  are  35  feet  high  and  6  inches  in  girth  at  a 
yard  from  the  ground. 

At  the  present  time  the  cultivation  of  Hevea  rubber  trees  in 
West  Africa  is  somewhat  experimental,  but  it  is  anticipated  that 
this  phase  will  soon  be  passed.  The  African  Plantations,  Ltd., 
according  to  the  report  issued  in  March,  1907,  have  several  thou- 
sands of  young  plants  growing  on  their  property  at  Axim.  Plants 
which  were  received  in  June,  1906,  had  grown  to  a  height  of  3  to 
4  feet  in  8  to  9  months,  and  the  best  developed  showed  a  height  of 
over  6  feet  9  inches  and  a  girth  of  24  inches.  The  African  Rubber 
Co.  reported,  in  1909,  the  girths  of  Hevea  trees  of  different  ages 


90  PARA    RUBBER 

growing  at  Axim,  Gold  Coast ;  trees  i8  months  old  measured  4  to 
4I  inches,  at  36  months,  9  inches,  and  at  45  months,  11  to  12 
inches.  On  the  Ivory  Coast,  at  Dabou,  there  were  (J.  d'Agr. 
Trop.,  Nov.,  1909)  trees  planted  in  1897-1898  yielding  seeds  and 
measuring  in  girth  from  31^  to  51  inches  at  16  inches  from  the 
ground. 

Small  plantations  of  this  species  have  been  made  in  Liberia, 
and  there  is  every  reason  to  feel  satisfied  at  the  growth  already 
obtained.  The  experiments  made  in  many  parts  of  East  and 
Central  Africa  are  not  so  encouraging  as  those  in  West  Africa,  the 
dry  climate  and  occasional  frost  preventing  continuous  and  rapid 
growth  in  the  former  areas. 

Growth  of  Hevea  Trees  in  Uganda,   Etc. 

According  to  H.M.  Commissioner's  Report  a  Hevea  rubber 
tree,  4-I  years  old,  growing  in  that  Protectorate,  was  'zy\  feet  high, 
with  a  girth  of  12J  inches  4  feet  from  the  ground.  About  200 
trees,  2^  years  old,  grown  from  seed,  were  about  17  feet  high. 
There  has  been  much  commercial  activity  in  regard  to  this  pro- 
duct, and  ventures  on  a  large  scale  were  pending  some  time  ago. 

Unexpected  interest  is  now  manifested  in  the  cultivation  of 
Hevea  hrasiliensis  in  Uganda,  and  the  following  details  of  rates  of 
growth  given  by  Kaye  (I.R.J.,  March  7th,  1910),  are  of  im- 
portance : — 

The  first  Hevea  tree  was  planted  in  1902,  and  it  has  made 
fine  progress.  Measured  on  the  31st  March,  1909,  it  had  a  height 
of  42  ft.  4  in.  and  30  in.  girth.  The  increase  during  the  year  was 
5  ft.  9I  in.  in  height  and  5-^-  in.  in  girth.  Other  trees,  in  the 
Botanic  Gardens,  showed  an  increased  height  of  7  ft.  4  in.  in  one 
year,  and  an  increase  of  2\  in.  in  girth  during  the  same  period. 

Hevea  trees  (from  Ceylon)  planted  December,  1903,  in  rich 
loam  on  clay  subsoil,  were  measured  every  six  months,  and  gave 
the  following  measurements: — 


No.  of  Tree. 

I 

2 

3 

4- 

When  measured. 

ft. 

ins. 

ft. 

ins. 

ft.  : 

ins. 

ft.  ins. 

Nov.  1906. 

Height  . . 

20 

10 

21 

9 

18 

3 

19 

0 

Girth  . . 

8 

6i 

6i 

7 

Apr.  1907. 

Height    .. 

22 

H 

23 

II 

19 

9 

22 

3 

Girth  . . 

9i 

7* 

7* 

7 

Nov.  1907. 

Height  .. 

25 

3 

29 

0 

20 

6 

16 

0 

Girth  . . 

I 

0 

10 

II 

10 

Apr.  igo8. 

Height    .. 

25 

4 

32 

10 

21 

5 

27 

8 

Girth  . . 

12 

12 

12 

12 

Nov,  1908. 

Height  .. 

29 

0 

34 

3 

21 

II 

29 

3 

Girth  . . 

I 

2 

I 

2i 

I 

I 

I 

I 

Apr.  1909. 

Height   .. 

30 

6 

41 

2 

25 

6 

34 

2 

Girth  . . 

I 

3 

I 

3 

I 

2 

I 

3 

Kaye  further  states  that  the  growth  of  the  Hevea  trees, 
compared  with  that  of  other  species  in  the  same  area,  promises 
to  be  exceptionally  good. 


PARA    RUBBER 


91 


In  Nyasaland,  266  survivors  from  a  wardian  case  of  Hevea 
seedlings,  despatched  from  Ceylon  in  1906,  had  a  height  of  5  feet 
in  January,  1907,  and  12  feet  in  July,  1908. 

Growth  in  the  West  Indies  and  Surinam. 

There  are  very  few  records  at  present  available  which  show 
the  average  annual  incremental  growth  in  parts  of  Trinidad  and 
Jamaica  where  this  species  has  been  planted,  though  the  general 
opinion  appears  to  be  that  the  growth  is  not  as  favourable  as  in 
the  East  Indies. 

In  an  issue  of  the  West  Indian  Bulletin,  Sharp  states  that 
Hevea  hrasiliensis  will  not  jdeld  so  early  or  so  abundantly  as 
Castilloa  elastica  and  is  not  so  suitable  as  a  shade  tree  for  cacao  ; 
he  further  states  that  in  dry  districts,  Hevea  will  probably  thrive 
better  than  Castilloa,  on  account  of  its  being  a  much  hardier  plant. 
These  statements  were  intended  to  apply  to  Jamaica  only ; 
it  is  obvious  they  do  not  agree  with  the,  results  of  experience  in 
the  East  Indies. 

The  interest  in  Hevea  cultivation  in  Trinidad  is  more  pro- 
mising. At  the  experiment  station  some  trees,  8|  years  old, 
are  35  feet  high  and  6  to  9  inches  in  diameter.  Hart  stated 
(Bulletin  No.  55,  July,  1907)  that  the  seeds  were  in  great 
demand  and  that  the  crop  on  the  Government  trees  would  not 
meet  the  demand  ;  he  also  informed  us  (Bulletin  No.  54,  April, 
1907)  that  the  largest  tree  under  cultivation  in  Trinidad  stands  a 
short  distance  from  the  residence  of  the  Governor,  Government 
House.  In  a  recent  issue  of  the  W.I.  Bulletin,  it  is  stated  that  on 
St.  Clair  lands,  which  are  well-drained,  but  of  a  sandy  alluvial 
character,  Castilloa  grows  faster  than  Hevea  in  the  first  two  years, 
but  later  the  Hevea  outgrows  the  Castilloa. 

On  the  island  of  Grenada  some  three-year-old  plants  are  20 
feet  high. 

Barbados,  St.  Lucia,  Montserrat,  Dominica,  etc.,  have  not 
yet  taken  up  a  very  prominent  position  in  the  cultivation  of 
Hevea  hrasiliensis,  but  whether  this  is  due  to  unfavourable  climatic 
conditions  or  otherwise  is  not  clear. 

Pearson  records  (I.R.  World,  Jan.,  1911)  that  on  the  occasion 
of  his  visit  to  Surinam  he  saw  trees  at  the  Botanic  Gardens  eight 
years  old  which  girthed  28  inches,  others  of  the  same  age  at 
Waterlands  measured  31I  inches,  while  12-year-old  trees  varied 
in  girth  from  35I  to.sgj  inches. 

Growth  of  Stem  under  Special  Circumstances. 

The  foregoing  statistics  relate  to  trees  which  have,  in  the 
various  countries,  generally  been  grown  under  ordinary  plantation 
conditions  ;  these,  though  variable,  have  come  to  be  regarded  as 
normal  for  each  country.  There  are,  however,  special  circum- 
stances under  which  the  rate  of  growth  of  the  stems  is  of  unusual 
interest. 


92  PARA     RUBBER 

Rate  of  Stem  Growth  under  Forest  Coxditions. 

One  of  the  most  interesting  features  in  the  Botanic  Gardens, 
Singapore,  is  the  block  of  Hevea  trees  in  and  under  forest.  The 
Hevea  rubber  tree,  on  account  of  the  rapidity  with  which  the  seeds 
lose  their  germinating  capacity,  has  only  a  poor  chance  to  spread 
in  primitive  forest.  Long  before  the  seed  finds  a  bit  of  soil,  it 
may  have  lost  its  germinating  power  through  exposure  to  un- 
favourable climatic  conditions.  Even  if  it  germinates,  it  has  to 
compete  with  the  roots  of  and  shade  from  the  surrounding  plants, 
and  finally  to  combat  many  natural  forest  enemies  before  it  can 
top  its  highest  neighbour.  Ridley  gave  an  account,  in  1908, 
of  the  trees  to  which  I  refer.  It  appears  that  in  the  year  1894 
some  one  planted  rubber  seedhngs  in  a  wood  behind  his  house  in 
the  Botanic  Gardens.  This  wood  is  on  the  slope  of  a  hill  running 
down  to  the  main  road  and  rather  steep.  It  had  been  planted 
up  by  Mr.  Cantley,  in  1884,  with  Alhizzia  violuccana,  Euginia 
grandis  and  other  trees,  and  had  additions  in  the  form  of  various 
trees  of  the  character  of  belukar  jungle.  The  rubber  trees  were 
quite  forgotten  for  about  ten  years,  and  when  found  were  crowded 
among  other  trees,  but  had  made  surprisingly  rapid  growth. 
The  tallest  was  measured  quite  recently.  It  had  grown  consider- 
ably higher  than  the  surrounding  trees,  and  was  conspicuous 
from  afar.  Its  height  was  found  to  be  no  less  than  a  hundred 
feet,  while  in  girth  at  three  feet  from  the  ground  it  measured  72 
inches.  The  stem  was  smooth  and  straight  without  a  branch 
for  a  considerable  height.  The  other  two  were  not  so  tall,  one 
having  lost  a  portion  of  the  top.  One  measured  60  inches  at 
three  feet  from  the  ground,  and  the  third  gave  a  measurement 
of  79  inches. 

On  the  slope  the  trees  lessen  in  girth  in  proportion  to  the 
steepness  of  the  hill,  the  slopes  of  which  show  signs  of  a  strong 
rush  of  water  during  rains.  The  whole  wood  is  full  of  seedlings 
from  these  trees,  although  for  some  years  past  it  has  been  the 
custom  for  the  seed  collectors  to  gather  up  the  fallen  seeds. 

The  usual  height  given  for  a  full-grown  Hevea  tree  is  70  feet 
and  the  tall  tree  is  certainly  the  record  in  height,  and  yet  it  is  but 
fourteen  years  of  age.  The  trees  are  grown  in  a  thick  wood  of 
lofty  trees,  on  a  stiff  and  poor  clay  soil.  They  have  cost  nothing 
more  than  the  mere  putting  of  the  seedlings  into  the  ground, 
except  that  when  they  were  rediscovered  some  trees  which  were 
pressing  against  them  were  knocked  down.  They  are  grown  under 
absolutely  natural  conditions,  just  as  one  sees  them  in  photographs 
of  the  trees  of  the  Amazons,  and  they  are  fully  twice  as  large 
as  trees  of  the  same  age  grown  in  the  open,  with  careful  and 
expensive  felling  and  clearing  and  weeding,  and  are  reproducing 
themselves  naturally  through  the  forest. 

The  trees  have  been  tapped,  and  good  returns  of  rubber 
obtained. 


PARA     RUBBER  93 

The  following  are  their  measurements  (age  14  years)  ;  48  in., 
38in.,  28  in.,  60  in.,  72  in.,  38  in.,  41  in.,  42^  in.,  79  in.  The  three 
trees  with  the  greatest  girth,  viz.,  those  of  60  in.,  72  in.,  and  79  in. 
circumference,  grew  higher  up  the  slopes.  The  average  annual 
growth  in  girth  at  three  feet  from  the  ground  of  these  big  trees 
in  the  last  four  years  was  2'o6,  2*87  and  4-06  inches.  The  ordinary 
growth  in  girth  of  big  trees  in  general  is  about  2  inches  a  year. 
Younger  trees  seem  to  grow  faster. 

The  following  measurements  of  the  trees  planted  in  1894 
were  given  by  Ridley  (Str.  Bull.  July,  1908)  : — 


Girth  in  Inches. 

Position. 

1904. 

1905- 

1906.     1907- 

1908 

Top  of  Hill  .  . 

■    62f 

68J 

7if      75i 

79 

>. 

6oi 

62J 

65f      68i 

72 

>» 

53f 

57i 

58       59i 

60 

Slope 

■   38* 

4oi 

42^      447 

48 

■   33J 

36i 

4if      42 

424 

•   34i 

36i 

38       40 

41 

34 

35 

35f      36f 

38 

31 

32 

34i      36? 

38 

24 

244 

26       27 

28 

Influence  of  Elevation  on  Rate  of  Growth. 

The  trees  planted  in  the  experimental  plots  on  Gunong  Angsi 
at  various  elevations  have  been  measured  (Rep.  Dir.  Agr.  F.M.S., 
1910)  :— 

Elevation  Percentage  Elevation  Percentage 

in  feet.  ready  to  tap.  in  feet.  ready  to  tap. 

300  69  1800  18 

600  18  2100  o 

1000  48  2400  2 

1600  27 

It  is  remarked  that  although  the  trees  at  600  feet  have  not 
•done  well,  the  results  tend  to  show  that  the  higher  the  elevation 
the  slower  the  growth  of  the  trees.  The  trees  at  an  elevation 
of  2,400  feet  look  as  healthy  as  those  at  300  feet. 

Influence  of  Age  on  Rate  of  Growth. 

The  fact  that  thirty-year-old  Hevea  trees  have  a  girth  of 
120  inches,  and  are  still  growing,  may  lead  some  planters  to  imagine 
that  the  rate  of  growth  is  more  or  less  constant  throughout  the 
life  of  the  tree.  This  is  far  from  being  the  case  even  when  trees  are 
not  tapped  ;  when  the  bark  is  regularly  excised  quite  a  number 
of  variations  may  be  expected.  During  the  first  two  or  three 
years  Hevea  trees  in  the  open  grow  mainly  in  length,  the  long 
spindly  character  of  young  clearings  of  this  age  being  quite 
characteristic.  Once  they  have  attained  a  length  of  20  to  30  feet 
and  thrown  out  lateral  branches  the  rapid  increase  in  girth  com- 
mences, and  continues,  generally,  until  the  trees  are  10  to  15 
years  old.  After  that  time  the  relative  growth  in  height  and 
girth  is 'largely  dependent  on  the  spacing  of  the  trees,     Ridley 


94  PARA    RUBBER 

(Str.  Bull.,  July,  1910)  states  that  the  ratio  of  increment  varies 
according  to  the  age  of  the  tree,  and  gives  the  following  measure- 
ments in  support  thereof  : — 


Hevea  trees. 

1904. 

1905. 

1906. 

1909. 

Increment 
in  6  years. 

5  years  old. 

I'   sr 

I'      9¥ 

2'     iF 

2'   iif 

I'     si' 

5 

I'      61" 

1'      irj" 

2'  3r 

3'      of" 

r'      ej" 

16 

3'   9r 

3'    iir 

4'  3' 

4'    lof 

t'        t' 

28' 

9'     iV 

9'       3i" 

9'  sr 

10'      oj" 

0'  11' 

Ridley  does  not  say  whether  or  not  these  are  averages.  He 
estimates  the  ratio  of  growth,  where  the  general  conditions  are 
fair,  from  5  to  15  years  at  3  to  4  inches  ;  from  15  to  20  years  at 
2  to  3  inches  ;  and  from  20  to  30  years  at  i  to  2  inches,  per  annum. 

The  normal  increment  of  growth  may  be  modiiied  in  any 
particular  year  through  prolific  seeding. 

Baxendale  (Jugra  Estate,  Annual  Report,  1908)  stated 
that  there  was  a  decided  check  to  growth  in  the  6th  year  on  fields 
planted  10  by  10  feet,  but  that  where  the  trees  were  planted  15  by 
15  feet  this  check  was  not  evident  for  quite  a  year  later. 

Girth  Increases  Calculated,  per  Acre. 

In  the  chapter  on  cultivation  the  effect  of  distance  in  planting 
on  the  rate  of  growth  has  been  demonstrated.  Berkhout  (Trop- 
enpflanzer,  September,  1910),  gives  some  interesting  data  re- 
garding the  rate  of  growth  and  its  significance,  per  acre,  on  Tali 
Ayer  estate.  Province  Wellesley.  The  following  are  his  measure- 
ments : — 


Distance. 

Age. 

Average  Girth.     Age. 

Average  Girth. 

Average  in- 
crease in 

6  months. 

20'  by  20' 

4 J  years 

2oi" 

5  years 

23" 

2r 

20'  by  18' 

3i     „ 

1 8  J" 

4i     ., 

2oi" 

ir 

36  by  10' 

4i     ,. 

i8r 

5       .. 

20J" 

iS'by  15' 

4        ,. 

19*' 

4i     „ 

2ir 

ij' 

18' by  10' 

4J     .. 

I5i" 

5       .. 

161" 

i" 

The  trees  planted  20  by  20  feet,  109  per  acre,  show  a  half- 
yearly  total  increase  of  109  by  2|  inches  =  300  inches  per  acre  ; 
those  planted  18  by  10  feet,  or  242  per  acre,  242  by  i  inch  =  242 
inches  per  acre.  The  total  girth  per  acre  of  the  trees  of  any  age  is 
of  course  given  by  multiplying  the  number  of  trees  per  acre  by  the 
girth  at  that  age. 

Census  of  Trees. 

It  has  become  customary  on  many  estates  to  obtain  a  census  of 
the  trees,  especially  prior  to  tapping,  in  order  to  determine  the 
number  of  trees  having  a  definite  circumference.  This  informa- 
tion, if  obtained  annually,  enables  anyone  to  calculate  the  average 
rate  of  growth  and  the  number  of  trees  which  can  be  tapped  in 
future  years. 


PARA     RUBBER 
Ryan's  Callipers. 


95 


The  simple  appliance  invented  by  Mr.  James  Ryan  affords 
an  easy  way  of  determining  the  circumferences  of  trees.  The 
implement  consists  of  a  pair  of  callipers  rotating  on  an  axis  ;  at 
one  end  is  a  pointer  which  moves  over  a  graduated  scale.  The 
callipers  clasp  the  stem  and  when  the  implement  is  withdrawn  the 
circumference  of  the  tree  is  indicated  by  the  pointer  on  the  scale. 


RYAN  S  CALLIPERS. 


This  simple  appliance  will  be  very  useful  to  planters  when 
preparing  an  annual  statement  of  the  rate  of  growth  of  their  young 
trees,  or  when  determining  the  average  sizes  prevaihng  over 
various  parts  of  the  property. 

Burgess's  Method  of  Measuring  Girth. 

Mr.  P.  J.  Burgess's  device  for  taking  measurements  of  rubber 
trees  has  lately  been  improved.  It  is  a  simple  method,  requiring 
nothing  but  what  can  be  made  on  the  estate,  and  enabling  a  coolie 
who  cannot  read  or  write  to  measure  and  record  the  girth  of  a 
thousand  trees  per  day. 

The  device  is  made  as  follows  :  A  wooden  stick  is  taken  about 
3  feet  6  inches  long,  and  at  3  feet  from  one  end  a  leather  strap 
is  fastened  ;  this  strap  is  about  i  to  2  inches  wide,  and  of  a  length 
eaual  to  the  maximum  growth  expected  to  be  recorded.  It  is 
fastened  at  right  angles  to  the  stick,  and  in  such  a  way  that 


96 


PARA     RUBBER 


about  6  inches  of  it  projects  on  one  side  of  the  stick.  This  pro- 
jecting portion  is  cut  narrow  so  that  its  width  is  about  half  an  inch. 
One  surface  of  the  strap  is  smooth,  the  other  surface  may  be  left 
rough,  and  the  strap  is  attached  with  the  smooth  side  next  to  the 
stick.  Into  the  end  of  the  short  projecting  portion  a  steel  pin 
is  fixed  ;  on  to  the  smooth  surface  of  the  strap  a  long  strip  of  paper 
is  pasted.  The  illustrations  depict  a  manufactured  set  of  sticks, 
etc. 


"-^^V-^V^;;^ 


s 


E 


PIN 

\ 

-^•1 

1 — H — n 1 

1 

BURGESS  S    MEASURING    DEVICE. 


The  stick  is  used  as  follows  :  The  coolie  places  the  stick 
upright  against  the  tree  to  be  recorded,  with  the  rough  side  of 
the  leather  against  the  tree,  this  brings  the  short  piece  carrying 
the  pin  to  the  right  hand  of  the  coolie  ;  the  long  strip  is  then 
wrapped  round  the  tree  trunk  and  brought  tight  across  the  stick 
above  the  short  strip  of  leather.  The  coolie  then  makes  a  prick 
mark  in  the  paper,  puts  a  chalk  mark  on  the  tree  to  show  that  it 
has  been  measured,  and  passes  on  to  the  next  tree. 


PARA    RUBBER 


97 


The  coolie  does  not  personally  do  any  reading  of  measures 
or  writing  at  all. 

At  the  end  of  the  day  the  sticks  are  brought  in  to  the  superin- 
tendent, who  first  marks  out  the  strip  of  paper,  and  then  counts 
the  prick  marks.  The  paper  is  set  out  as  follows  :  The  strap  is 
extended  fiat  on  a  table,  and  with  an  inch  ruler,  distances  in  inches 
are  set  off  on  the  lower  margin  of  the  paper,  inclined  lines  are 
then  ruled  as  shown  in  the  illustration  (this  inclination  is  to  allow 
for  the  swing  of  the  pin  on  the  short  strip  of  leather  when  the 
pricking  is  done  by  the  coolie).  The  superintendent  then  counts 
the  pricks  in  each  section,  and  the  number  gives  the  trees  of  that 
girth  measured.  If  the  highest  accuracy  be  required  and  the 
thickness  of  the  leather  be  allowed  for,  the  strap  may  be  set  out 
by  obtaining  a  fixed  point  on  the  paper  by  actual  measurement 
of  some  tree  with  a  tape  and  then  seeing  where  that  measurement 
will  appear  on  the  paper  when  the  tree  is  measured  by  the  apparatus 
and  setting  off  from  that.  In  practice,  this  is  not  necessary,  but 
the  superintendent  is  recommended  to  do  it  for  his  own  satisfac- 
tion once  or  twice. 

When  the  returns  are  counted,  it  will  be  seen  that  there 
is  with  all  areas  planted  at  anything  like  regular  periods  a  regu- 
larity in  the  results,  the  numbers  of  trees  increasing  to  a  maximum 
about  the  mean  girth  and  then  decreasing. 

If  the  coolie  fancies  it  easier  to  sit  down  and  fake  his  measure- 
ments by  pricking  at  random,  this  is  at  once  shown  on  counting,, 
because  the  results  are  then  irregular  and  no  systematic  increase 
and  decrease  is  discernible.  It  wiU  be  noted  that  this  method  is. 
rapid,  it  does  not  require  skilled  labour,  it  is  independent  of 
reading  and  writing,  and  it  automatically  sorts  out  the  measure- 
ments into  their  order  of  girths. 

There  is  little  difficulty  in  the  counting  if  the  pins  are  kept 
sharp.  One  hundred  and  fifty  pricks  per  area  are  easily  counted,, 
and  the  error  owing  to  two  pricks  occurring  in  the  same  hole  is 
less  than  two  per  cent.  With  care  this  error  can  be  entirely 
avoided. 

The  device  was  invented  by  Mr.  P.  J.  Burgess  in  1906,  and 
has  been  practically  tested  and  used  on  several  estates  and  found 
perfectly  satisfactory. 

The  first  set  of  four  sticks  which  were  used  to  count  174,343 
trees  were  made  on  the  estate  out  of  four  broom-sticks,  four 
drawing-pins,  and  four  bag  straps. 

Rate  of  Growth  of  Foliage.  ' 

Before  passing  to  the  consideration  of  methods  of  cultivation, 
when  planting  distances  must  be  enquired  into,  it  will  be  useful 
to  learn  what  is  known  of  the  rates  of  growth  of  the  crowns  of 
foUage  and  of  the  root-systems. 

The  diameters  of  the  branch  and  foliar  system  of  trees  of 
known  ages  measured  on  rubber  properties  in  Ceylon  are  here 
given  ;    it  must  be  understood  that  the  growth  has  been  obtained 


93  PARA    RUBBER 

where  Hevea  is  interplanted  with  cacao  or  tea.  The  growth  is 
very  variable.  The  Hevea  stumps  were  from  one  to  two  years 
old  when  planted. 

Diameter  of  Branches  with  Foliage. 

Age  of  Badde- Katu- Nilam- Knuck-    Pera-    Sahara- Watte-   Kalu- 

Trees.  Matale.  gama.  gastota.  be.        cles.      deniya.  gamuwa.  gama.     tara. 
Years,      ft.  ft.         ft.         ft.  ft.  ft.  ft.  ft.         ft. 

22  —  3——  3  15  3  8 

3  4  to  44     —         —         —  —  —  -^  —  " 

4  134  12  12  to  13      19  '" 

6  —  13  —  —  —  —  28  —  17 

7  15  to  24     18         —         —  —  —  —  —  20 

8  —  —         29         —  —  —  37  —  25 

9  —           —         —     17  to  30     —           —  —  23  25 
lo     32  to  34     —         —         —           —           —  —            28  33 

II—  —         —         —  —  —  —  —  35 

13         _______  __46 

15     27  to  46  —  —  —  —  —  —  —  — 

25         —  _  _  _  _  15  to  43  —  —  — 

30        —  —  —  —  —  28  to  40  —  —  — 

Elevation 

in  feet.   1,200  50  1,500  2,200  2,500  1,500  600  2,200  100 

Rainfall 

in  inches.  77  119  85  130  175  90  170  80  to  90  130 

Where  the  trees  are  planted  closer  than  10  by  15  feet  apart 
they  will  probably  show  a  greater  height  and  smaller  circum- 
ference. One  tree,  ten  years  old,  grown  more  or  less  in  the  open, 
has  a  spread  of  36  feet,  whereeis  one  of  the  same  age  surrounded  with 
other  trees  has  a  spread  of  only  20  feet.  The  largest  tree  in 
Ceylon,  when  thirty  years  old  from  seed,  measured  about  90  feet 
in  height  and  109J  inches  in  circumference,  and  there  were  many 
others  of  the  same  age  which  had  a  circumference  of  8  to  9  feet 
and  a  height  in  proportion  to  the  above  examples.  Several  of  the 
old  Henaratgoda  trees,  owing  to  their  being  too  closely  planted, 
have  only  a  branch  spread  to  15  to  20  feet  in  diameter. 

Rate  /jf  Growth  of  Root-System. 

The  tree  has  a  very  well-developed  root  system  which  may 
ultimately  crowd  out  many  intercrops  if  planted  too  close.  The 
tap  root  may  grow  to  a  considerable  length  and  the  lateral  rootlets 
form  a  very  compact  mass.  It  is  on  account  of  the  rapidly- 
growing,  compact,  and  superficial  root  system  that  plants  such 
as  the  coconut  and  other  palms,  tea  and  coffee,  cannot  be  grown 
successful^  for  very  many  years  in  conjunction  with  Hevea, 
except  the  latter  are  widely  planted.  The  lateral  roots  grow  at 
varying  rates  according  to  the  conditions  prevailing,  but  if  grown 
alone  on  moderately  good  and  fiat  land,  an  incremental  minimum 
yearly  increase  in  radius  of  about  one  to  two  feet  can  be  allowed 
for  ;  individual  roots  will,  of  course,  grow  much  more  rapidly.  In 
six  to  seven  years  the  lateral  roots  (growth  of  which  is  of  high 
importance)  of  plants  distanced  12  by  12,  in  Ceylon,  may  be 
expected  to  form  a  compact  mass  ;     planted  10  by  15  feet  the 


Chas.   IsJoitliu-aij. 
ROOTS     OF      HEVEA      TREES     13     YEARS     OLD. 


Is* 


tj'. 


Kf  *": 


4fci^i 


V 


*8^ 


^'^,. 


1    s      '     '|«ifci?    - 


PARA     RUBBER 


99 


larger  distance  will  be  more  or  less  completely  covered  in  7  to  8 
years  ;  in  richer  soils  the  rate  of  root  growth  is  much  more  rapid, 
and  a  much  wider  distance  of  20  by  20  feet  or  18  by  24  feet  would, 
in  Klang,  be  covered  in  the  same  period  of  time. 

The  root  system  of  young  Hevea  rubber  plants  (especially  the 
outer  zone),  though  superficial,  is  not  as  compact  as  that  of  an  old 
tree.  There  are  always  a  large  number  of  lateral  roots  on  young 
plants  which  grow  much  more  rapidly  than  the  rest,  but  the 
compact  root  system  does  not  usually  advance  at  a  rate  much  above 
one  to  two  feet,  radially,  each  year.  Individual  roots  have  been 
described  as  growing  at  the  rapid  rate  of  one  foot  per  month  ;  but 
no  figures  having  been  published,  I  meanwhile  judge  the  rate  of 
growth  of  the  compact  root  system  from  observations  made  when 
carrying  out  trench- manuring  experiments  with  young  trees  at 
Peradeniya. 

These  considerations  of  growth  lead  us  to  the  subject  of  cultiva- 
tion of  Hevea  hrasiliensis  in  various  countries,  and  the  means 
adopted  to  maintain  or  increase  the  regular  development  of  all  parts 
of  the  tree. 


CHAPTER    VI. 

PLANTING    OPERATIONS    AND    METHODS    OF 
CULTIVATION. 

It  has  been  shown  that  the  countries  possessing  the  largest 
acreages  of  Hevea  trees  are  Malaya,  Ceylon,  Java,  Sumatra,  and 
South  India.  The  methods  adopted  by  planters  in  these  areas 
furnish  striking  examples  of  the  diversity  of  opinion  among  them 
and  of  the  adaptability  of  the  plant. 

Method  of  Cultivation  in  Malaya. 

In  Malaya  Hevea  is  cultivated  over  continuous  stretches  of 
country,  often  as  a  single  product.  If  one  passes  through  Perak 
or  Selangor  one  is  impressed  by  the  flatness  of  the  land,  relieved 
here  and  there  by  small  hillocks  or  ' '  bukits, ' '  hills  of  any  great 
size  being  rarely  met  with.  Hevea  saplings  are  visible  everywhere, 
and  one  estate  is  often  only  separated  from  another  by  a  stretch  of 
high  lalang.  From  Kuala  Lumpur  to  Klang  is  a  typical  case. 
Many  estates  are  established  on  grass  or  lalang  ground  or  on  land 
which  has  grown  sugar  or  tapioca  for  several  years  ;  the  majoritj- 
are,  however,  planted  on  land  which  was  previously  in  heavy 
jungle.  Protective  forest  belts  of  immense  size  are  said  to  have 
been  selected  by  Government  to  divide  one- district  from  another, 
so  that  in  the  event  of  some  disastrous  disease  or  pest  arising  it  may 
to  some  extent  be  isolated  ;  these  may  afford  little  comfort  to 
those  within  such  belts.  Most  estates  in  Malaya  grow  Hevea 
alone  ;  a  few  have  unwisely  planted  Hevea  among  coconuts.  The 
principal  catchcrop  is  tapioca,  which  is  especially  favoured  by 
Chinese  and  native  planters.  Sugar,  indigo,  and  bananas  are  also 
grown,  the  former  especially  in  Province  Wellesley.  Among 
the  characteristics  of  much  of  the  land  are  the  nearness  to  sea-level 
and  the  occurrence  of  water  near  the  surface.  There  is  nothing 
in  Ceylon,  Sumatra,  or  Java,  to  compare  with  the  vast  tracts  of 
Hevea  growing  in  the  flat,  wet  land  in  parts  of  Province  Wellesley 
and  Selangor.  The  land  is  usually  very  well  drained,  the  soil  very 
fertile,  and  the  trees  are  planted  at  relatively  wide  distances. 
Clean-weeding  is  the  system  generally  adopted,  only  a  few  estates 
growing  Passiflora  and  other  weed-killers.  The  rate  of  growth 
of  the  trees  during  the  first  six  years  is  probably  quicker  than  in 
any  other  country. 

Hevea  Cultivation  in  Ceylon. 
Compared  with  Malaya,  Hevea  is,  in  Ceylon,  grown  under  a 
much  greater  variety  of  conditions.     It  is  rarely  grown  on  land 
with  the  water-level  so  near  the  surface ;   it  is  usually  cultivated 


Tl^"S.   -> 


Lfitt   by   Indnt-Ihiblxr  Jourjutl. 
HEVEA      AND      ALBIZZIA      TREES. 


Lfint  hv   lufVa-Iiublier  Journal. 
HEVEA       NURSERY. 


Uj; 


Lent   by    India-Ihibhrr  Journal. 
HEVEA    GROWING    AMONG    ROCKS. 


PARA     RUBBER  loi 

on  undulating  or  hilly  land,  often  abundantly  provided  with 
huge  boulders.  Nowhere  else  in  the  East  does  one  meet  with  such 
large  acreages  of  Hevea  growing  on  rocky  hillsides  ;  estates  in  the 
Kalutara  and  Kadugannawa  districts  furnish  good  examples  of 
Hevea  thriving  successfully  on  rocky  slopes.  The  estates  are 
generally  no  higher  than  i,ooo  feet  above  sea-level ;  quite  a 
number  of  notable  properties  are,  however,  above  this  elevation. 
Peradeniya,  where  some  of  the  original  trees  were  planted,  is  about 
1,500  feet  above  sea-level,  and  several  Hevea  estates  exist  in  the 
surrounding  districts  at  even  higher  altitudes.  The  soil  is  generally 
poor,  but  well  drained  ;  the  water-level  is  usually  many  feet  or 
yards  below  the  surface.  The  trees  are  planted  more  closely  than 
in  Malaya,  favourite  distances  being  15  by  15  feet  or  15  by  20  feet. 
In  many  parts  of  the  Kelani  Valley  and  |Calutara  one  meets  with 
immense  stretches  of  country  cultivated  with  Hevea  only.  The 
view  from  the  summit  of  one  of  the  hillocks  often  reveals,  at  the 
tops  and  beyond  the  hills,  along  valleys  and  small,  drained  swamps, 
the  spindly  stems  and  whorls  of  foliage  of  Hevea  saplings  of  all 
sizes  and  ages.  But  this  is  not  the  only  type  of  vegetation. 
Hevea  is  cultivated  in  association  with  tea  and  cacao  to  an  extent 
which  is  not  always  realised.  Nearly  100,000  acres  of  the  Hevea 
in  Ceylon  are  mixed  with  tea  at  low  and  medium  elevations  or 
with   cacao   at   medium   elevations. 

Tapioca  or  sugar  are  rare  ;  bananas  are  occasionally  met  with 
on  rubber  estates.  The  relative  poverty  of  the  soil,  and  the 
interplanting  on  numerous  estates,  has  resulted  in  a  slower  rate  of 
growth  than  Malaya  ;  manuring  is,  however,  now  being  carried 
out  extensively.  Clean-weeding  is  the  one  system  recognised  by 
most  experienced  planters.  Terracing,  by  means  of  stones,  is 
occasionally  done  where  trees  are  planted  on  very  steep  hillsides  ; 
this  is  more  frequently  seen  in  Java,  and  rarely  in  Malaya  or 
Sumatra. 

Hevea  in  South  India. 

In  this  country  Hevea  is  grown  at  low,  medium,  and  high 
altitudes.  A  large  area  in  the  hill  country  is  intercropped  with 
coffee,  and  the  growth  of  the  rubber  is  relatively  slow.  In  the 
Travancore  and  Cochin  districts  it  is  mainly  grown  as  a  single 
permanent  crop,  and  is  there  showing  comparatively  rapid 
growth.  The  methods  of  cultivation  and  general  configuration 
of  the  estates  are  somewhat  similar  to  those  in  Ceylon,  with  the 
exception  of  coffee  replacing  cacao  and  tea  as  the  intercrop. 
The  rate  of  growth  at  low  altitudes  is  quite  equal  to  that  in  Ceylon, 
and  is  frequently  above  the  average  for  the  latter  place. 

Method  of  Cultivation  in  Java. 
On  many  estates  Hevea  has  been  interplanted  among  exist- 
ing cultivations,  such  as  cacao  and  coffee,  or  these  products  have 
been  planted  with  or  after  the  Hevea.  Some  plantations  are 
being  catch-cropped  with  tapioca,  citronella,  lemon  grass  or 
groundnuts.     It  is  therefore  obvious  that  Java  rubber  planters  do 


102  PARA    RUBBER 

not  generally  rely  entirely  on  rubber,  but  sometimes  prefer  to 
adopt  a  mixed  cultivation,  such  as  is  seldom  seen  in  any  other 
country.  I  hke  to  see  mixed  products  on  the  same  ground  for 
obvious  reasons  ;  but  I  cannot  help  thinking  that  on  many  estates 
in  Java  it  is  overdone.  Where  the  same  estate  has  its  rubber 
planted  through  or  with  nutmegs,  Liberian,  Java  and  robusta 
coffee,  Ceara,  Castilloa,  cacao,  kapok,  and  other  useful  trees, 
the  attention  of  the  manager  is  necessarily  diverted.  He  will 
not  cut  out  his  nutmegs  or  kapok  trees  while  the  Hevea  saphngs 
are  young,  and  in  the  long  run  his  estate  consists  of  too  many 
products,  few  of  which  have  attained  perfection  ;  it  is  a  natural 
consequence  on  overplanted  estates. 

The  best  estates  I  have  seen  in  Java  consist  of  Hevea 
alone  or  with  a  crop  of, either  robusta  coffee,  cacao,  or  tapioca. 
One  catch  or  intercrop  under  the  rubber  saplings  is  generally 
quite  enough  even  on  phenomenally  rich  soil.  The  results  obtained 
on  Kalu  Minggir,  Poerwodjojo,  and  the  Java  Rubber  Plantations 
certainly  justify  one  in  advising  one  or  other  of  these  systems. 

A  feature  of  all  Ceylon  estates  along  hillsides,  and  even  on 
flat  ground,  is  the  draining,  the  drains  being  i  to  ih  ft.  wide  and 
deep,  and  running  at  right  angles  to  the  slope.  In  East  Java  I 
never  saw  anything  approaching  this,  except  on  flat,  swampy 
areas.  The  hillsides  are  not  drained  on  a  regular  system,  a  few 
water  pits  being  the  only  receptacles  provided  to  collect  the  water 
and  prevent  excessive  wash.  The  soil  is  so  rich  that  a  little 
wash  may  take  place  without  seriously  affecting  the  development 
of  the  plants  ;  but  surely  it  is  to  the  interest  of  all  to  retain,  by 
means  of  drains,  as  much  soil  as  possible  under  all  conditions. 
I  commend  the  subject  to  the  consideration  of  planters  in  East 
Java.  I  cannot  think  that  Ceylon  is  wasting  labour  and  money  in 
draining  ;  it  is  just  as  essential  for  rubber  cultivation  as  for  tea. 

Another  point  which  struck  me  somewhat  forcibly  after 
travelling  through  Perak  was  that  in  East  Jav^  very  few  sugar 
estates  were  planting  Hevea  among  the  sugar  canes.  A  few 
may  be  doing  this,  but  I  did  not  see  the  properties. 

Cultivation  in  Sumatra. 

The  cultivation  of  rubber  plants  in  Sumatra  is  almost  limited 
to  lands  near  sea-level,  and  thereby  resembles  Malaya  and  differs 
from  Java,  Ceylon,  and  Southern  India.  The  soil  is  very  similar 
to  that  in  Java,  being  light,  fertile,  and  mainly  of  volcanic  origin. 
I  have  not,  in  Sumatra,  seen  anything  resembling  the  stiff  blue 
clay  of  Malaya  or  the  rocky  slopes  of  Ceylon ;  everywhere  the  soil 
is  finely  divided  and  porous,  and  grows  magnificent  crops.  The 
sugar  of  Java,  and  the  tea  and  cacao  of  Ceylon,  are  replaced  by 
extensive  plantations  of  tobacco  in  Sumatra.,  Exactly  why 
Java  takes  so  ravenously  to  sugar  and  Sumatra  to  tobacco, 
though  each  country  could  probably  grow  both  products  very  well 
indeed,  is  difficult  to  explain.  The  only  product  which  is  com- 
monly grown  on  European  plantations  in  Java  and  Sumatra,  to  a 


PARA    RUBBER  103 

large  extent,  is  coffee.     In  both  countries  the  coffee  estates  are 
being  rapidly  interplanted  with  Hevea. 

Hevea  cultivation  in  Sumatra  was  not  commenced  in  earnest 
much  before  1906,  and  I  do  not  think  manufacturers  can  expect 
many  tons  of  rubber  from  that  island  before  1913  or  1914.  A  few 
estates,  such  as  those  owned  by  the  United  Serdang,  Langkat 
Snmatra,  United  Sumatra,  Sumatra  Para,  and  Amsterdam- 
Langkat  Companies,  possess  several  thousands  of  old  or  tappable 
trees.  Most  estates,  however,  consist  of  coffee  interplanted 
with  Hevea  or  old  tobacco  or  lalang  lands  planted  up  with  Hevea 
during  the  last  two  or  three  years.  There  are  very  few  estates 
consisting  of  Hevea  trees  alone,  and  in  this  respect  Sumatra 
comes  irito  line  with  most  other  countries. 

Shade  in  Java  and  Malaya. 

I  was  much  impressed  with  what  I  saw  on  one  estate  in 
East  Java  during  May,  1908.  In  parts  of  East  Java  the  dry 
season  may  extend  over  a  period  of  six  or  seven  months,  and 
it  has  become  a  planting  custom  in  that  area  to  develop  everything 
under  the  shade  of  trees — especially  Dadaps.  Liberian,  Arabian 
and  robusta  coffee  bushes,  and  cacao  trees  are  all  under  the 
same  shade,  though  in  the  adjacent  island  of  Sumatra  the  former 
products  are  grown  in  the  open.  On  the  estate  to  which  I  refer 
the  Hevea  trees,  now  two  years  old,  had  been  grown  under  the 
shade  of  high  Dadap  trees  ;  they  were  spindly  and  backward  for 
their  age,  and  I  consequently  advised  the  owner  to  ring  the  shade 
trees  to  let  in  more  light. 

At  the  Botanic  Gardens,  Singapore,  Mr.  Ridley  showed  me 
a  number  of  very  large  Hevea  trees  which  had  been  developed 
under  the  shade  of  tall  forest  trees.  The  trees  were  fifteen  to 
twenty  years  old  and  several  were  quite  equal  in  size  to  others 
which  had  been  grown  in  the  open.  The  seedlings  were  planted 
among  the  forest  trees  and  allowed  to  develop  as  best  they  could  ; 
the  fact  that  such  fine  development  can  be  obtained  proves  how 
the  plant  can  overcome  the  effect  of  unfavourable  conditions. 

In  Java  and  Sumatra  the  best  growth  of  Hevea  is' obtained 
without  permanent  -shade  ;  the  foregoing  examples  are,  however, 
of  interest. 

In  the  F.M.S.,  according  to  Carruthers',  the  shading  of  rubber 
plants  is  generally  of  very  little  importance  owing  to  the  absence 
of  severe  droughts  in  that  part  of  the  tropics  ;  it  is  only  recom- 
mended in  districts  where  "seed  at  stake"  is  the  method  of 
planting,  and  where  dry  weather  may  occur  within  ten  weeks 
after  planting. 

It  would  be  unfortunate  if  Hevea  required  a  permanent 
shade,  as  there  are  but  few  shade  trees  which  could  be  relied 
upon  to  always  outreach  the  tops  of  tall  rubber  trees,  especially 
when  the  latter  have  never  been  pruned  and  when  planted  very 
close.  Only  trees  such  as  Alhizzia  moluccana  and  perhaps  Ery- 
thrina  lithosperma  would  combine  the  quick  growth  and  spreading 


104  PARA    RUBBER 

of  branches  which  would  be  necessary.  Trees  of  Peltophorum  and 
Pterospermum  species,  etc.,  though  attaining  huge  dimensions, 
grow  at  too  slow  a  rate,  especially  when  cultivated  in  conjunction 
with  other  tree  forms. 

Hevea  trees  generally  develop  better  if  shaded  after  being 
planted,  and  a  hght  shade  for  the  first  and  second  years  such  as  is 
given  by  cuttings  or  plants  of  Erythrina  species  is  often  beneficial. 
After  their  second  year  they  grow  satisfactorily  without  shade. 

Damage  by  Wind. 

In  an  article  on  rubber  in  the  Journal  of  the  Board  of  Agricul- 
ture, of  British  Guiana  (October,  1910),  it  is  stated  that  when  trees 
of  Hevea  brasiliensis  have  been  exposed  to  the  strong  winds 
of  the  coastal  lands  of  the  colony  a  marked  dry  spell  of  weather  has 
resulted  in  a  general  shedding  of  leaves.  The  same  effect  has  been 
noticed  in  other  situations,  and  it  seems  fairly  definitely  established 
that  exposure  to  wind  not  only  retards  growth,  but  often  results 
in  frequent  change  of  leaf.  It  is  anticipated  that  the  frequent 
change  of  leaf  may  materially  affect  the  quantity  of  latex  from 
the  trees  when  the  tapping  stage  is  reached. 

Windbelts  are  generally  only  necessary  during  the  early  stages: 
owing  to  the  protection  from  wind  which  the  mature  trees  give 
to  one  another  and  their  general  strength,  special  forest  belts  can 
be  disregarded  except  in  very  windy  places,  where  the  retention  of 
jungle  or  planted  belts  to  break  the  wind  is  a  feasible  way  out  of  the 
difficulty. 

Much  damage  is  frequently  done  in  Sumatra  and  Malaya  by 
squalls,  and  it  is  customary  in  many  districts  to  estimate,  when 
planting  the  estates,  for  a  certain  percentage  of  the  trees  to  be 
blown  over. 

In  Samoa,  which  is  liable  to  windstorms,  Preuss  suggested 
that  the  plantations  be  provided  with  windbreaks,  for  which  he 
thought  Ficus  elastica  suitable. 

Damage  is  also  reported  from  Fiji  (India-Rubber  Journal, 
February  8th,  1909),  where  the  trade-wind  continued  with  more 
than  usual  severity  and  practically  defoliated  Hevea  trees  which 
were  then  2J  years  old  and  had  a  height  of  20  feet. 

Forestry  on  Rubber  Estates. 

These  occurrences  draw  attention  to  the  lack  of  forestry 
methods  on  Eastern  estates,  though  the  plants  cultivated  are  typical 
members  of  the  forest  group.  The  only  general  pruning  of  trees 
is  that  of  removing  branches  below  a  certain  height  in  order  to 
maintain  a  clear  tapping  stem  up  to  a  minimum  of  ten  or  fifteen 
feet,  or  the  removal  of  the  terminal  bud  at  that  height  in  order  to 
encourage  the  production  of  lateral  branches.  Once  a  tree  has 
passed  this  stage  it  is  generally  left  to  take  care  of  itself.  It  is 
advisable  that  all  Hevea  trees  should  be  regularly  inspected  by 
competent  forest  officers  and,  if  necessary,  pruned  in  order  that 
well-balanced  specimens  be  ultimately  obtained.     This  would  save 


PARA     RUBBER  105 

■many  losses  during  windy  weather  and  would  give  symmetrical 
trees  capable  of  yielding  the  maximum  quantity  of  rubber  in 
future  years.  It  is  never  too  late  to  commence  this  important 
work,  though  it  is  ob  iously  an  advantage  if  it  can  be  carried  out 
from  the  first  year  onwards.  At  present  there  is  only  one  planta- 
tion company  in  the  East  which  has  realised  the  importance  of 
this  work  and  has  appointed  an  officer  to  deal  solely  with  it. 

Plant  Selection  for  Hevea. 

The  desirability  of  selecting  the  best-yielding  varieties  of 
Hevea,  or  of  propagating  by  seed  or  cuttings  only  from  trees  which 
are  known  to  be  sound  and  capable  of  yielding  large  crops  of 
rubber,  is  recognised  by  scientists  and  planters.  The  records  of 
yields  are,  however,  so  scanty  and  incapable  of  giving  reliable 
comparative  data,  that  the  task  presents  more  than  the  usual 
difficulties.  It  should,  nevertheless,  be  possible  to  determine 
the  yielding  capacities  of  the  offspring  in  Malaya  and  Ceylon  and 
to  compare  these  with  the  yields  obtained  from  their  seed  parents. 

The  advantages  of  improving  the  yielding  capacity  of  Hevea 
frees  from  one  generation  to  another  are  apparent  to  all.  The 
•difficulties  in  the  way  of  effecting  improvement  are  noteworthy. 
In  the  first  place,  the  yielding  capacity  cannot  be  determined 
by  tapping  until  the  trees  have  been  tapped  for  several  years  in 
succession,  and  then  an  interval  of  perhaps  ten  years  may  be 
necessary  before  any  reliable  data  can  be  obtained.  Secondly,  the 
effect  of  paring  the  bark,  whereby  large  quantities  of  living  tissue 
are  annually  removed,  must  have  a  deteriorating  effect  on  the 
trees  whence  seeds  or  cuttings  are  to  be  derived.  With  other 
plants,  notably  fruit  trees,  one  can  actually  improve  the  plant 
during  the  selecting  period.  Thirdly,  the  propagation  of  plants 
by  cuttings  is  relatively  difficult  and  would  not  be  very  successful 
if  carried  out  by  planters  not  provided  with  suitable  apparatus. 
Selection  by  seed  could,  of  course,  be  adopted,  but  this  method  is 
open  to  many  objections,  most  of  which  can,  however,  be  overcome 
if  the  work  is  done  by  a  specialist  in  plant-breeding. 

Habit  of  Trees  and  Yield. 

Vernet  (J.  d'Agr.  Trop.),  points  out  that  with  Ceara  trees 
there  are  two  types  ;  one  a  tall  tree  with  narrow  crown  and  longer 
but  fewer  branches  which  is  a  good  yielder  ;  the  other — shorter, 
■wider  crown,  with  many  and  shorter  branches,  a  bad  yielder. 
Labroy,  when  dealing  with  the  same  species,  suggests  that  in  the 
nursery  only  plants  which  have  attained  a  certain  height  should  be 
selected.  Johnson  claims  that  inferior  latex  is  yielded  by  trees 
having  relatively  thick  bark  with  numerous  fissures.  It  is  possible 
that  a  further  study  of  the  habit  and  general  vegetative  character 
of  Hevea  trees  of  varying  yielding  capacity  may  throw  light  on 
this  line  of  selection. 


106  PARA     RUBBER 

Artificial  Pollination  Experiments. 

Parkin  has  made  some  valuable  suggestions  (Souvenir,  I.R.J.) 
on  this  subject.  After  pointing  out  that  the  flowers  of  Hevea 
are  unisexual  and  that  the  male  part  can  be  easily  removed,  he 
states  that  artificial  pollination  "could  probably  be  carried  out 
without  a  vast  amount  of  trouble  or  difficulty.  The  female 
flowers,  after  the  removal  of  the  male  blossoms,  would  have  to 
be  covered  while  in  the  bud  stage  to  prevent  natural  poUination, 
and  then  be  fertihsed  by  the  pollen  from  the  selected  tree  when 
expanded  and  in  the  receptive  state.  The  covers  would  have  to 
remain  on  the  fertilised  female  flowers  till  the  capsules  were  ripe, 
in  order  to  retain  the  seeds,  which  otherwise  would  be  scattered 
by  the  explosive  mechanism  possessed  by  the  ripe  fruits.  It 
would  be  advisable  to  put  out  the  plants  raised  from  these  seeds 
in  a  position  away  from  all  other  Heveas,  so  that  when  they 
flowered  all  danger  of  pollination  from  the  outside  would  be 
removed.  The  yielding  capacity  of  these  trees  could  be  tested 
in  their  fourth  to  sixth  year  and  the  poor  ones  rejected.  Such  a 
plantation  in  a  few  years'  time  would  be  capable  of  supplying  a 
good  strain  of  seed,  and  also  afford  material  for  further  selection, 
and  so  continued  improvement. 

He  further  remarks  that  ' '  If  something  of  the  kind  had  been 
begun  ten  years  ago,  when  the  rubber  planting  industry  was  in  its 
infancy,  we  should  have  known  ere  this  whether  promising  results 
were  likely  to  be  forthcoming  or  not. 

"Perhaps  in  ten  or  twenty  years'  time  the  older  estates  will 
require  to  renew  some  of  their  trees.  It  would  be  a  boon  indeed 
if  seed  of  Hevea  could  then  be  obtained  guaranteed  to  produce 
trees  of  great  vigour  and  yielding  capacity. 

Selection  of  Seed  Parents  on  Est.'^tes. 

Selection  of  the  best  plants  during  transplanting  is,  as 
explained  elsewhere,  easily  done  ;  that  of  the  original  seed  parents 
on  the  estate  is  not  so  simple  a  matter. 

Seeds  from  trees  which  show  irregularity  in  quality  or 
quantity  of  latex,  should  perhaps  not  be  used  for  planting.  It  is 
difficult  to  give  practical  advice  on  the  subject  of  selecting  seed 
parents  when  all  the  trees  are  healthy  and  artificial  pollination  is 
not  resorted  to.  Personally,  I  should  select  my  seeds  from  the 
best- developed  trees  on  the  estate — those  which  show  the  best 
growth  of  foliage  and  girth  and  a  corresponding  laticiferous 
system.  It  seems  rather  dangerous  to  select  seeds  from  trees 
which,  though  showing  good  growth,  have  never  been  tapped  ; 
one  may  be  selecting  seeds  from  trees  which,  had  they  been 
tapped,  would  have  given  the  minimum  quanti  y  of  latex, 
or  perhaps  none  at  all.  Provided  the  trees  have  not  been  roughly 
handled  in  tapping  operations,  there  is  no  great  mistake  in  selecting, 
as  seed  parents,  those  trees  which  are  best  developed  and  have 
given  fair  yields  of  rubber.  There  is  a  theory  abroad  that  you  can 
induce  characteristics  in  the  vegetative  parts  of  plants  which  can 


PARA     RUBBER  107 

be  fixed  and  transmitted,  by  seed,  from  generation  to  generation, 
in  which  case  the  selection  of  seeds  from  the  best-yielding  trees 
might  ultimately  give  very  good  types  of  rubber  rees.  But  the 
theory  of  transmission  of  vegetative  characters  acquired  in 
successive  generations  is  hotly  contested  by  many  botanists, 
and  it  has  not  yet  been  proved  that  it  occurs  with  the  latex 
tubes  of  Hevea  brasiliensis. 

Selection  by  a  Chemical  Method. 

The  excellent  results  obtained  in  Java  in  improving  the  strain 
of  cinchona  trees  led  Dr.  Tromp  de  Haas  to  consider  the  possibility 
of  effecting  similar  improvements  in  Hevea  by  the  aid  of  chemical 
science.  When  cinchona  plants  were  first  introduced  into  Java 
the  bark  yielded  9%  of  quinine  sulphate  ;  to-day,  through  wise 
selection,  based  on  chemical  analysis  of  bark,  the  trees  produce 
bark  capable  of  yielding  17%  of  quinine.  Can  a  similar  result  be 
obtained  with  Hevea  ?  Planters  are  unable  to  do  anything  beyond 
determining  which  trees,  once  they  have  attained  the  tappable 
age,  produce  most  rubber  by  tapping.  If  bad-yielding  trees  are 
then  discovered,  it  is  too  late  and  practically  impossible  to  replace 
them. 

Dr.  Tromp  de  Haas,  referring  to  rubber  trees,  was  compelled 
to  admit  "that  the  analytical  method  cannot  claim  great  accuracy," 
and  that  analysis  already  made  ' '  cannot  distinguish  between  rich 
and  poor  trees."  The  fact  that  latex  is  a  liquid  in  circulation 
within  irregular  laticifers,  and  that  it  varies  greatly  in  its  distribu- 
tion and  contents  from  time  to  time,  will  always  have  to  be  faced 
in  any  analytical  method  of  plant  selection. 

Selection  by  Propagating  from  Cuttings  or  by 
Marcotting. 

Some  difficulty  appears  to  have  been  experienced  in  propa- 
gating from  cuttings.  Large  numbers  of  plants  were  raised  by 
cuttings  taken  from  the  original  seedUngs  brought  by  Cross  from 
S.  America  in  1876,  and  also  from  the  first  stock  of  plants  received 
in  Ceylon.  In  the  1906  report  of  the  Ceylon  R.B.G.  it  is  stated 
that  not  a  single  plant  was  obtained  from  3,000  cuttings.  A 
planter  in  Ceylon  has,  however,  raised  several  trees  from  cuttings. 

The  taking  of  cuttings  is  applicable  when  a  tree  or  variety 
produces  superior  rubber  or  larger  quantities  than  its  fellows,  or 
possesses  other  desirable  characteristics.  There  is  said  to  be  a 
better  chance  of  obtaining  the  coveted  characters  by  this  means 
than  by  planting  seeds. 

Success  has  been  reported  (T.A.,  November,  1907)  in  Java  by 
' '  marcotting. ' '  This  consists  of  selecting  a  promising  young 
growth,  remoying  a  ring  of  bark  off  the  stem  immediately  beneath 
a  node  or  leaf  scar,  and  keeping  the  area  moist  by  means  of  a 
bandage  of  moss  or  similar  material.  When  roots  are  produced, 
the  shoot  is  severed  from  the  parent  and  transplanted.  It  is  a 
method  which  can  be  tried  where  difficulty  is  experienced  in 
rooting  ordinary  cuttings. 


io8  PARA     RUBBER 

We  can  now  proceed  to  detail  the  ordinary  operations  on 
estates,  commencing  with  nurseries,  draining,  holing,  and  weeding, 
etc. 

Selection  During  Transplanting. 
It  is  seldom  that  much  care  is  bestowed  on  selection  during 
planting,  though  this  work  is  of  vast  importance,  and  if  generally 
done  would  result  in  better-grown  trees  and  more  evenly-developed 
plantations.  All  plants  which  have  twisted  taproots  or  stems, 
or  which  have  a  sickly  appearance,  or  have  been  attacked  by 
diseases  or  pests,  should  be  removed  and  destroyed.  They  should 
not  be  returned  to  the  nursery  with  the  intention  of  using  or  selling 
them  when  they  have  apparently  recovered  and  attained  the 
normal  size.  Those  plants  should  be  selected  for  planting  which 
have  shown  the  most  rapid  and  even  rate  of  growth  and  have 
been  immune  from  attacks  of  fungi  or  insects.  It  is  possible 
that  the  differences  in  rate  of  growth  evidenced  during  the  nursery 
period  will  be  maintained  when  the  seedhngs  are  planted  in  the 
clearings. 

Methods  of  Germinating  and  Planting. 

In  planting,  one  may  use  (i)  seeds  at  stake,  (2)  ordinary 
seedlings,  or  stumps,  and  (3)  nursery  plants  in  the  form  of  basket 
or  bamboo  seedlings. 

The  "seeds  at  stake"  method,  if  successful,  is  ihe  simplest 
and,  in  some  respects,  probably  the  best  known.  The  seeds  are 
placed,  one  to  three  in  each  refilled  hole,  and  then  covered  with 
twigs,  fern  leaves,  etc.,  to  provide  shade  during  the  first  few 
weeks.  If  more  than  one  plant  develops  in  each  hole,  the  weaker 
members  are  removed.  This  system  necessitates  clean-weeding 
from  the  commencement,  otherwise  the  young  seedhngs  are  soon 
choked.  Further,  the  seedhngs  are  greedily  eaten  by  animals, 
and  it  is  a  common  sight  to  see  them  nipped  off  near  the  base  ; 
fencing  around  each  plant  often  obviates  destruction  by  rats. 
If  dry  weather  immediately  follows  the  planting  of  the  seeds, 
there  may  be  a  large  percentage  of  deaths.  The  numerous 
difficulties  associated  with  this  method  have  led  most  planters 
to  adopt  nurseries  wherein  young  plants  can  be  reared  until 
they  are  several  months  old,  and  can  then  be  transplanted. 

The  rate  of  growth  of  plants  raised  from  seeds  at  stake  and 
nursery  stumps  is  indicated  by  the  following  figures  pubhshed 
in  Malaya  by  Campbell  (Annual  Report,  1909)  : — 


Seeds  sown 

Planted 

Average  girth. 

October,   1907 

out. 

1908. 

1909. 

1910. 

At  Stake      . . 

— 

3  'ffin. 

ejin. 

gi'Viin. 

In  Nursery  . . 

Dec,  1907 

2  ,"ijin. 

5lin. 

9?in. 

The  experiment,  therefore,  cannot  be  said  to  prove  the 
superiority  of  either  method.  The  point  to  determine  is  the 
comparative  net  value  of  clearings,  planted  at  the  same  time 
from  seeds  at  stake  and  from  nursery  stumps. 


PARA     RUBBER  109 

Nursery  Beds. 

If  It  IS  intended  to  use  stumps  or  ordinary  seedlings,  it  is 
necessary  to  lay  out  nursery  beds.  The  site  for  these  should 
be  well  chosen,  and  the  soil  thoroughly  dug  over  and  manured. 
The  same  site  should  not  be  used  two  years  in  succession,  except 
it  is  well  limed,  forked,  and  manured.  The  area  of  the  nursery 
beds  will  depend  upon  the  acreage  of  land  to  be  planted.  The 
beds  should  be  about  four  feet  wide,  and  be  separated  by 
earth  paths  in  order  that  no  damage  will  be  done  to  the  plants 
during  watering,  weeding,  and  inspection.  After  the  seeds  have 
germinated — this  generally  takes  place  in  about  10  days — they 
should  be  planted  in  the  nursery  beds  at  definite  distances  apart 
according  to  the  length  of  time  it  is  intended  they  shall  remain 
there  ;  a  distance  of  8  to  9  inches  is  sufficient  for  9  to  1 2 -month- 
old  plants.  If  they  are  planted  too  close  they  grow  very  spindly. 
The  larger  the  plant — in  an  interval  of  9  to  12  months — the  better. 
Good  growth  has  been  obtained  by  adding  cattle  manure  and  leaf- 
mould  to  the  nursery  soil  before  sowing  the  seed  .  An  application 
of  a  well-balanced  artificial  manure  to  the  nursery  plants  when 
about  four  months  old  will  also  help  them  on  and  give  better  stumps 
for  planting  in  due  course. 

All  nurserj'  beds  should  be  carefully  shaded  during  the  middle 
of  the  day,  and  be  watered  morning  or  evening  in  dry  weather. 
When  about  to  be  transplanted,  they  should,  for  several  days, 
be  ' '  hardened  off  "  by  gradual  removal  of  shade.  Transplanting 
should  only  be  done  during  cloudy  wet  weather  ;  this  is,  perhaps, 
not  of  much  importance  in  Malaya,  but  in  parts  of  Ceylon  and 
East  Java  where  dry  weather  is  apt  to  set  in  unexpectedly  it  is 
imperative.  It  is  not  practicable  to  water  the  plantation ; 
it  is,  however,  easy  to  give  the  nursery  a  thorough  watering  prior 
to  commencing  transplanting. 

PosmoN  OF  Seeds  in  Nursery  Beds. 

The  seeds  of  Hevea  hrasiliensis  are  longer  than  they  are 
broad,  and  it  is  usual  to  lay  the  seeds  horizontally  in  the  nursery 
beds.  If  the  seeds  are  sown  vertically  with  the  micropyle  end 
downwards  they  are  usually  pushed  above  ground  when  germina- 
tion takes  place  ;  if  they  are  placed  with  the  micropyle  end  upper- 
most the  seedlings  are  frequently  twisted.  It  is  much  safer  to 
lay  the  seedlings  horizontally,  as  by  this  method  straight  taproots 
are  usually  obtained. 

Nursery  Stumps. 

Stumps  are  generally  used  because  they  can  be  removed 
from  the  nursery  when  everything  is  ready  for  planting  ;  in  some 
countries,  owing  to  the  time  of  the  seed  crop,  it  is  impossible  to 
use  even  four  to  five-month-old  basket  plants,  stumps  therefore 
being  the  only  possible  way  out  of  the  difficulty. 

Th;  stumping  of  nursery  plants  is  a  very  drastic  operation, 
the  foliage  and  green  parts  above  ground,  and  also  the  lateral 


no  PARA     RUBBER 

roots  and  part  of  the  main  or  tap  root,  being  deliberately  cut 
away,  leaving  a  thin  rod  of  living  material  similar  in  general 
appearance  to  a  straight  walking-stick.  This  simple  structure, 
the  lower  part  of  which  is  root,  and  the  upper  part  stem,  is  put 
into  a  recently  re-filled  hole,  in  wet  weather,  and  allowed  to  throw 
out  roots  and  leaves  if  it  can.  It  is  a  marvel  that  so  many  stumps 
survive  and  grow  into  such  enormous,  healthy  trees.  Most 
of  the  nursery  plants  are,  when  thus  operated  upon,  less  than 
twelve  months  old. 

Transplanting. 

Planting  from  nursery  stumps  is  sometimes  the  only  system 
possible,  but  were  I  planting  my  own  property  it  is  the  last  method 
I  should  think  of  adopting.  I  heard  of  an  estate  where  several 
three-year-old  plants  were  stumped  and  planted  with  such  success 
that  a  visitor  to  the  estate  at  a  subsequent  date  put  two  years  on 
to  the  age  of  the  plantation.  But  whatever  the  appearances  of 
such  a  property  may  be,  it  is  as  well  to  remember  that  the  plants 
have  not  got  either  the  lateral  root  system  or  main  tap  root  which 
they  naturally  possess  and  require.  What  white  ants  would  do 
with  such  plants  may  be  conjectured. 

It  is  often  possible,  in  wet  and  very  cloudy  weather,  to  trans- 
plant from  the  nursery  into  the  field  without  stumping  the  seed- 
lings ;  in  such  cases  planters  usually  take  every  care  not  to  injure 
the  root  system,  this  being  achieved  by  removing  the  plant  with 
as  much  nursery  soil  as  possible.  It  would  appear  that  in  the 
transplanting  of  fruit  trees  in  England  (Report,  Wobum  Exp. 
Farm,  1908),  too  much  care  can  be  taken  in  preserving  the  rootlets. 
It  is  pointed  out  that  the  delicate  tips  of  the  roots  are  broken 
off,  in  ordinary  transplanting,  and  cannot  be  reformed.  The  new 
roots  develop  most  strongly  from  those  parts  of  the  old  roots  that 
are  thickest,  since  these  have  more  reserve  food  than  other  parts  ; 
this  reserve  material  accumulates  at  the  cut  end  of  a  thick  root, 
and  generally  causes  many  new  roots  to  form  there.  Again,  the 
closer  the  contact  of  the  soil  with  the  roots  of  a  transplanted 
tree,  the  more  readily  will  new  roots  be  formed.  Hence  the 
advantage  of  "ramming"  the  soil  immediately  after  planting. 
The  ' '  ramming ' '  is  likely  to  cause  breaking  of  the  roots,  but  some 
experiments  show  that  this  is  often  an  advantage  than  otherwise, 
for  more  numerous  roots  develop  at  the  place  of  injury.  Whether 
this  is  applicable  to  Hevea  trees  is  doubtful. 

Basket  Plants. 

The  use  of  seed-baskets  is  to  be  recommended  whenever 
practicable,  and  it  is  a  matter  for  regret  that  the  success  with  which 
stumps  can  be  used  has  led  to  the  disuse  of  baskets  in  many 
districts.  Considering  that  so  few  trees  are  planted  per  acre,  and 
that  baskets  are  so  cheap,  the  disuse  of  the  latter  at  the  expense  of 
the  interruption  in  development  of  the  rubber  plant  is  to  be 
regretted.     The  Neboda  Tea  Co.,  Ceylon,  in  their  annual  report 


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PARA     RUBBER  in 

for  1905,  attributed  the  success  of  clearings  to  the  use  of  basket 
plants. 

The  results  which  have  been  obtained  by  the  use  of  basket 
plants — seedlings  reared  in  friable,  loose  baskets  for  two  or  four 
months,  and  planted  in  the  field  without  destroying  or  even  dis- 
turbing the  foliar  or  root  structures — are  magnificent,  especially 
when  compared  with  those  obtained  from  stumps.  There  is  a 
minimum  number  of  vacancies  and  less  likelihood  of  encouraging 
white  ants,  borers,  and  fungi  when  basket  plants  or  seeds  at 
stake  are  used  ;  the  cuts,  bruises,  and  dead  parts  on  stumjjed 
seedlings  are  sources  of  danger. 

The  splendid  growth  obtained  on  rubber  estates  planted 
with  basket  plants  has  attracted  attention  even  in  Europe,  one 
firm  having  gone  to  the  trouble  of  ordering  a  trial  consignment  of 
empty  baskets  from  Ceylon  for  use  on  their  West  African  planta- 
tion. If  the  baskets,  which  are  not  procurable  in  West  Africa, 
can  be  dehvered  at  the  latter  place  at  a  reasonable  cost,  they  will 
be  extensively  used  on  the  rubber  and  cacao  estates  now  rapidly 
springing  into  being  in  that  part  of  the  world. 

I  would  recommend  this  to  some  Sumatra  planters  who 
do  not  believe  in  anything  except  stumps,  the  roots  of  which  they, 
for  some  unknown  reason,  cut  back  to  about  six  inches.  Stump- 
ing is  a  method  only  to  fall  back  upon. 

Plants  in  bamboo  pots  are  sometimes  used,  especially  for 
old  specimens,  but  the  method  does  not  offer  any  great  ad- 
vantages over  ordinary  baskets,  which  readily  decay  when  put 
out  in  the  field. 

Burning  and  Removal  of  Timber  on  Clearings. 

After  felling  the  forest  and  piling  and  burning  the  branches 
in  the  field,  many  planters  commence  lining  and  holing.  A  good 
burn  means  -sterilisation  of  soil  in  local  areas  and  a  consequent 
reduction  in  weeding  expenses  ;  furthermore,  it  assists  in  the 
destruction  of  pests.  There  is,  even  after  the  best  burn,  a  quantity 
of  timber  which  hitherto  has  been  allowed  to  rot  in  situ  with  the 
exception  of  the  smaller  material.  Francis  Pears  states  that 
' '  the  orthodox  $4  to  $7  per  acre  for  clearing  after  a  burn-off  of 
virgin  jungle  is  not  nearly  sufficient.  By  spending  $40  to  $50, 
much  money  and  worry  will  be  saved  after  planting,  and  the  odds 
are  that  much  better  yields  will  be  obtained  when  the  area  comes 
into  bearing." 

Now  we  find  that  it  often  pays  on  many  properties  to  go  to  a 
very  large  expense  in  uprooting  the  stumps  of  trees  and  removing 
partly-burnt  timber.  This  course  has  resulted  in  a  diminution 
of  diseases  and  pests,  especially  white  ants  and  Fomes.  Estates 
near  towns  are  able  to  dispose  of  the  timber  on  new  clearings 
without  much  cost,  but  on  other  estates  it  is  necessary  to  hire 
elephants  and  use  estate  labour  to  clear  it  off  the  areas  about  to  be 
pilanted.  In  some  parts  of  Sumatra  where  the  estates  are  low- 
lying  and  subject  to  floods,  it  is  reported  that  considerable  damage 


112  PARA     RUBBER 

has  been  done  by  loose  timber.  On  clearings  two  years  old  the 
floods  have  carried  the  loose  timber  through  the  estates,  and 
have  finally  piled  it  against,  and  destroyed  many  of,  the  trees. 

This  method  of  completely  clearing  contrasts  markedly 
with  that  recommended  by  Wickham,  who  evidently  believes  in 
only  partial  clearing  of  the  forest,  then  planting,  and  cutting 
down  the  growth  from  time  to  time,  allowing  it  to  decay  in  situ. 
Experience  in  the  East  has  convinced  me  that  the  best  course 
is  :    burn  all  you  can,  and,  if  possible,  remove  the  rest. 

Timber  on  Secondary  and  Lalang  Clearings. 

Some  planters  beUeve  in  felling  the  virgin  forest,  burning 
as  much  as  possible,  and  then  allowing  secondary  growth  to 
appear,  which  can  be  subsequently  feUed  prior  to  planting.  The 
advocates  of  this  system  state  that  the  interval  permits  of  some 
of  the  larger  trees  decapng.  In  my  opinion  it  is  a  system  hable  to 
let  in  all  manner  of  weeds  and  to  materially  increase  the  opening 
costs.  Furthermore,  the  stumps  of  hard  woods  do  not  decay 
much  under  ten  years.  Many  advocate  the  planting  of  lalang 
ground  from  which  all  timber  and  root  stumps  have  disappeared. 

The  advantages  and  disadvantages  from  a  plant  sanitation 
standpoint  of  estabhshing  rubber  plantations  on  lalang  are  dis- 
cussed elsewhere.  It  has  been  pointed  out  that  one  cannot  now 
regard  lalang  as  a  weed  against  which  organised  effort  is  useless  ; 
and  further  there  is  much  to  be  said  in  favour  of  such  land  for 
Hevea  on  account  of  the  absence  of  tree  stumps  in  the  soil  with  the 
consequent  relative  immunity  from  root  diseases  and  white  ants. 

Uprooting  Tree  Stumps. 

The  cost  of  uprooting  tree  stumps  in  forest  clearings,  apart 
from  the  difficulty  of  finding  suitable  apparatus,  has  long  deterred 
planters  from  carrying  out  this  most  desirable  work.  The  subject 
is,  however,  receiving  attention,  and  success  has  been  recorded 
on  some  estates.     In  some  cases  jacks  have  been  used. 

A  planter  in  Sumatra  estimates  (I.R.J.,  Nov.  ist,  1909)  that 
a  jack  worked  by  two  Javanese  is  capable  of  grubbing  from  70  to  80 
roots  or  small  stumps  per  day.  It  is  capable  of  uprooting  trees 
from  one  to  two  feet  in  diameter,  and  should  therefore  be  of  great 
service  in  opening  up  operations.  When  operating  upon  dead 
timber,  the  jack  does  its  work  with  little  or  no  aid  from  spade  or 
axe.  In  dealing  with  green  timber,  it  is  often  necessary  to  dig  a 
Uttle  round  the  base  of  the  stump  and  cut  through  some  of  the 
surface  roots  before  appl5ring  the  jack.  For  removing  roots  and 
sunken  stones  it  is  only  necessary  to  dig  a  small  hole  on  one  side  in 
order  to  ajlow  the  claw  of  the  jack  to  get  a  hold. 

In  Malaya  it  is  customary  to  fell  the  forest  trees  at  a  height 
of  several  feet  above  the  the  level  of  the  ground,  the  stumps  being 
allowed  to  remain,  in  situ,  until  they  decay  and  fall  down.  This 
contrcLsts  most  unfavourably  with  the  custom  in  Ceylon  where  all 
jungle  is,  in  felling  operations,  cut  as  near  to  the  ground  as  possible. 


PARA     RUBBER 


III 


Fencing. 

This  work  is  necessary  if  the ,  vacancies  are  to  be  kept  at  a 
minimum.  Animals  attack  Hevea  at  all  stages,  particularly 
during  the  first  and  second  years,  and  the  amount  of  damage 
done  to  young  clearings  by  rats,  hares,  porcupines,  pigs,  deer,  and 
cattle  cannot  be  too  seriously  considered.  If  it  is  intended  to 
cultivate  catch  crops  which  are  equally  attractive  to  animals, 
fencing  is  imperative.  The  boundaries  of  newly-planted  clearings 
are  often  enclosed  in  coarse  wire  netting,  but  where  the  rubber  is 
planted  in  established  products,  such  as  tea,  cacao,  coffee,  etc., 
it  is  usually  sufficient  to  fence  around  each  plant,  either  with 
netting  or  sticks.  When  coarse  netting  is  used  the  plants  are 
protected  by  a  circle  of  netting  about  six  to  nine  inches  from  the 
plant  to  a  height  of  3  or  more  feet.  When  the  boundaries  of 
estates  are  fenced  it  is  necessary  to  use  from  8  to  13  strands  of 
strong  wire  ;  the  lower  ones  being  close  together,  and  the  upper 
strands  about  one  foot  apart.  A  high  strong  fence  is  necessary 
to  keep  out  animals  of  the  porcupine,  pig,  and  deer  types. 

A  type  of  fencing  which  appears  to  be  particularly  strong  and 
known  as  "  Hercules  "  is  now  being  supplied  to  estates. 


The  "Hercules' 


Fencing. 


As  will  be  seen  from  the  above  illustration  this  fencing,  made 
from  galvanized  English  spring  steel  wire,  consists  of  horizontal 
and  vertical  strands  at  varying  distances  from  one  another.  The 
strength  of  this  type  appears  to  be  partly  due  to  the  fact  that 
each  wire  is  supported  by  others  and  knotted  together  in  a 
peculiar  way. 


114  PARA     RUBBER 

Draining. 

It  is  erroneous  to  suppose  that  because  Hevea  is  a-  forest 
cultivation  draining  is  unnecessary.  Draining  is  as  necessary 
for  rubber  trees  as  it  is  for  any  other  product  in  order  to  encou.age 
the  free  circulation  of  air,  water,  and  food  solutions  throughout 
the  soil,  and  to  check  wash  on  steep  hillsides. 

The  distance  of  the  drains  from  one  another  and  their  size 
must  depend  upon'  the  soil  conditions.  In  swampy  and  boggy 
land,  little  above  the  water-level,  the  drains  should  be  as  wide  and 
deep  as  possible,  either  between  each  row  of  trees  or  in  exceptional 
cases  around  individual  trees.  Several  areas  in  the  low-country 
of  Ceylon,  consisting  of  bogs  rich  in  organic  matter,  have  been 
converted  into  good  rubber  land  by  making  drains  two  to  three 
feet  wide  and  three  to  four  feet  deep,  and  heaping  the  earth  in 
the  middle  to  form  a  dry  soil  on  which  the  rubber  plant  can  live 
for  a  couple  of  years.  One  authority  with  South  American 
experience  (T.A.,  January,  1909,)  has  suggested  that  thorough 
drainage  as  is  being  done  in  the  East  may  lead  to  trouble,  and 
believes  it  is  better  to  imitate  the  Amazon  conditions,  and  have 
low,  swampy  land,  preferably  submerged  for  a  part  of  the  year, 
and  always  damp  enough  to  prevent  the  underground  burrowing 
of  the  trees'  enemies  !  This  advice  is  not  likely  to  be  taken  too 
seriously. 

On  hillsides  the  drains  need  be  only  about  one  to  one-and-a- 
half  feet  deep.  They  should  be  made  at  right  angles  to  the  slope 
in  order  to  check  the  formation  of  gorges.  The  distance  of  the 
drains  from  one  another  will  vary  according  to  the  slope  and 
climatic  conditions  ;  on  flat  land  a  distance  of  60  to  100  feet  seems 
sufficient,  whereas  on  steep  hillsides  20  to  30  feet  is  not  too  close. 
They  are  usually  about  ij  feet  wide  and  deep,  but  in  swampy 
land  or  in  very  wet  districts  they  are  not  only  closer  together 
but  considerably  larger  ;  on  some  Selangor  estates  they  are  3  feet 
wide  and  deep. 

Terracing  and  Silt  Traps. 

In  some  parts  of  Ceylon,  South  India  and  Java,  where  the 
land  is  very  steep,  terraces  are  dug  along  which  the  Hevea  trees 
are  planted.  Malays  and  Chinese  also  terrace  the  hills  on  which, 
nutmeg  and  clove  trees  are  grown.  Where  the  soil  is  very  rocky 
and  digging  is  impossible,  stones  are  arranged  around  each  tree, 
on  the  lower  side,  to  check  wash.  In  steep  parts  of  East  Java! 
where  ordinary  "Ceylon  drainage"  is  rarely  met  witt,  large  pits 
are  dug  at  regular  distances  to  collect  the  silt  ;  on  very  steep 
estates  a  silt  trap  is  recommended  for  each  tree  ;  this  method 
is  not  applicable  when  the  estates  are  rocky,  but  it  is  easily  adopted 
with  the  hght  volcanic  soils  in  Java  and  Sumatra.  On  some 
estates  they  are  distanced  about  twenty  apart,  and  are 
{T.A.,  March,  1910,)  about  4  feet  long,  15  inches  wide,  and  15 
inches  deep  ;  on  other  properties  (T.A.,  April,  1910,)  they  are 
14  feet  by  18  by  18  inches.     The  pits  collect  the  fine  soil,  leaves. 


PARA    RUBBER  115 

twigs,  etc.,  and  require  to  be  cleared  out  regularly  ;  the  contents 
should  have  a  high  manurial  value.  A  suggestion  has  been  made 
(T.A.,  May,  1910,)  that  if  Hevea  grows  well  on  flat  land  periodically 
flooded,  it  should  thrive  through  the  gradual  percolation  of  water 
caught  in  these  silt  traps. 

Holing  and  Filling. 

The  question  of  holing  should  be  well  considered,  as  the 
rubber  plant  is  a  greedy  feeder  and  responds  to  generous  treatment. 
The  holes  should  be  ij  feet  deep  and  as  wide  in  area  as  possible  ; 
if  made  i  J  by  2  by  2  feet  they  would  not  be  any  too  large.  The 
larger  the  holes  the  better  for  the  plant.  Good  holing  will  give 
the  plants  an  excellent  start  ;  the  dribbling  in  of  seeds  in  small 
alavangoe  holes  is  not  to  be  recommended.  When  the  holes  are 
re-filled,  two  or  three  weeks  prior  to  planting,  only  the  top  soil  and 
the  scrapings  should  be  used  ;  the  bottom  soil  from  the  holes 
should  always  be  kept  separate  and  discarded.  It  is  hardly 
necessary  to  point  out  that  the  planting  operations  should  be  carried 
out  when  rain  is  plentiful ;  the  plants  should,  if  necessary,  be 
stumped,  but  every  care  taken  to  avoid  unnecessary  destruction 
of  sound  roots.  Frequently  seedlings  can  be  successfully  planted 
without  being  stumped.  The  stumps  will  stand  one  or  two  weeks' 
drought,  but  if  dry  weather  continues  for  a  long  period  the  soil 
around  the  plants  should  be  shaded.  In  some  instances,  where 
it  has  been  necessary  to  plant  in  moderately  dry  weather,  the 
nurseries  have  been  flooded  for  two  or  three  days  prior  to  the- 
plants  being  removed,  and  the  results  have  been  considered  good. 
The  holes  should  be  re-filled  with  soil  for  a  couple  of  weeks  before 
planting,  so  that  shrinkage  may  take  place  before  planting  is  done^ 

Distance  in  Planting. 

It  is  a  principle  recognized  in  forestry  that  close  planting  will 
give  tall  trees,  and  wide  or  open  planting  thick  trees.  One  object 
in  planting  Hevea  rubber  is  to  produce  trees  which  will,  as  early 
as  possible  after  the  fourth  or  sixtH  year,  give  a  straight  stem  of 
at  least  ten  to  fifteen  feet  in  height  and  a  circumference  of  18 
inches  or  more.  Such  trees  can  be  tapped.  If  the  trees  are  very 
tall,  but  have  a  circumference  of  much  less  than  18  inches,  tapping 
operations  are  generally  impossible  owing  to  the  smallness  of  the 
available  tapping  area  from  6  feet  downwards.  And  such  trees 
8  years  old  are  known,  this  undesirable  result  being  the  outcome 
of  too  close  planting  and  not  thinning-out  or  pruning  the  trees  at 
the  proper  time.  In  parts  of  Ceylon  trees  have  been  planted 
10'  by  10',  12'  by  12',  14'  by  14',  15'  by  15',  and  15'  by  20'.  It 
should  be  mentioned  that  trees  in  the  Federated  Malay  States, 
planted  36'  by  36',  showed  contact  of  branches  in  nine  years,  and 
in  Ceylon  the  branches  of  trees  planted  forty  feet  apart  have  been 
known  to  meet  in  ten  years.  A  very  popular  distance  for  Hevea 
alone  in  Ceylon  is  15'  by  20',  in  Malaya  12'  by  24',  and  20'  by  20' ; 
in  Sumatra  a  distance  of  20'  by  20'  is  often  provided. 


Ii6  PARA     RUBBER 

Number  of  Trees  per  Acre. 
The  following  table  indicates  from  the  distances  of  planting 
(square  or  oblong)  the  number  of  trees  to  the  acre  : — 


ft. 

8 

10 

12 

13 

14 

15 

16 

17 

18 

20 

25 

30 

35 

40 

8 

68o 

546 

453 

418 

388 

363 

340 

320 

302 

272 

217 

181 

155 

136 

10 

546 

435 

363 

335 

3" 

290 

272 

256 

242 

217 

174 

145 

124 

108 

12 

453 

363 

302 

279 

259 

242 

226 

213 

201 

181 

145 

121 

103 

90 

13 

418 

335 

279 

257 

239 

223 

209 

197 

186 

167 

134 

in 

95 

83 

14 

388 

3" 

259 

239 

222 

207 

194 

186 

172 

155 

124 

103 

88 

77 

15 

363 

290 

242 

223 

207 

193 

i8i 

170 

161 

145 

Ii6 

96 

82 

11 

16 

340 

272 

226 

209 

•194 

181 

170 

160 

151 

136 

108 

90 

77 

68 

17 

320 

256 

213 

197 

186 

170 

160 

151 

142 

128 

102 

85 

73 

64 

18 

302 

242 

201 

186 

172 

161 

151 

136 

134 

121 

96 

80 

69 

60 

20 

272 

217 

i8i 

167 

155 

145 

136 

128 

121 

io8 

87 

7; 

62 

54 

25 

217 

174 

145 

134 

124 

116 

108 

102 

96 

87 

69 

58 

49 

43 

30 

181 

145 

121 

HI 

103 

96 

90 

85 

80 

72 

58 

48 

41 

36 

35 

155 

124 

103 

95 

88 

82 

77 

73 

69 

62 

49 

41 

35 

31 

40 

136 

108 

90 

83 

77 

72 

68 

64 

60 

54 

43 

36 

31 

27 

Total  spread 

of  the  Branches 

Number  of  trees 

in  Diameter. 

per  Acre. 

12  feet 

302 

15  .. 

t93 

25  .. 

70 

30  „ 

30 

35  ,. 

35 

40  ., 

27 

Number  of  Trees  per  Acre  at  Certain  Ages. 

In  order  to  allow  the  plants  to  develop  freely  in  girth  the 
maximum  distance  should  be  allowed,  as  the  desired  length  of 
trunk  is  usually  obtained  even  when  the  Hevea  tree  is  grown  in 
the  open.  From  considerations  of  the  condition  of  trees  from  4  to 
15  years  old,  the  following  table  is  compiled  in  order  to  show  the 
probable  number  of  Hevea  trees  of  known  age  an  estate  can  bear 
without  interfering  with  the  natural  growth  of  the  plants  : — 

Age  of  Trees. 

Four  years  old 

Six  „ 

Eight 

Ten 

Twelve 

Fifteen 

This  shows  the  approximate  number  of  trees  to  the  acre  at 
different  ages  without  any  serious  interference  of  the  branches  of 
adja:cent  trees  with  one  another.  There  is,  however,  no  objection 
to  the  branches  of  trees  partially  overlapping,  and  it  is  more 
than  likely  that  any  excessive  branch  development  will  be  kept 
back  by  pruning  or  pollarding  rather  than  by  reducing  the  number 
of  trees  much  below  100  per  acre. 

Hexagonal  Planting. 

The  advantages  of  hexagonal  planting  have  been  discussed 
in  the  India-Rubber  Journal,  August  8th,  1910.  It  was  there 
pointed  out  that  in  square  planting  the  trees  are  set  out  in  rows  at 
right  angles  to  one  another.  In  hexagonal  planting  each  tree  is 
equidistant  from  six  others  which  surround  it,  there  being  rows 
in  three  directions  crossing  each  other  at  angles  of  60  degs., 
dividing  the  field  into  a  series  of  equilateral  triangles  with  a  tree 


PARA     RUBBER  117 

at  each  angle.     It  is  evident  that  a  larger  number  of  trees  can  be 
grown  to  the  acre  this  way. 

Various  Opinions  on  Distances  in  Planting. 

Gumming  has  expressed  the  opinion  that  distance  in  planting 
depends  a  great  deal  on  the  configuration  of  the  land.  Closer 
planting  is  possible  on  hilly  land  than  on  flat,  .because,  he  states, 
the  light  has  more  chance  to  get  among  trees  on  the  slopes  of  hills 
than  on  level  ground.  He  thought  that,  from  his  observations, 
close  planting  would  during  the  first  few  years  give  more  rubber 
than  wide  planting. 

Gallagher  (F.M.S.  Bull.  No.  10)  estimates  that  on  virgin  jungle 
land  from  15  to  20  per  cent,  of  the  trees  originally  planted  will, 
through  fungi,  white  ants,  wind  and  poor  trees,  have  been  lost  by 
the  time  the  trees  are  seven  years  old.  He  recommends  com- 
mencing with  120  to  140  per  acre,  in  order  that  about  100  trees  per 
acre  may  remain  when  they  are  seven  years  old.  He  does  not 
point  out  that  the  percentage  of  vacancies  is  much  smaller  if  the 
estate  is  originally  widely  planted. 

After  a  visit  to  Eastern  estates,  Berkhout,  late  Conservator 
of  Forests,  Java,  expressed  his  approval  of  close-planting,  though 
he  agreed  that  judicious  thinning-out  was  necessar}^^  subsequently. 
It  was  quite  a  mistake,  he  maintained,  to  suppose  that  every  acre 
of  an  estate  should  bear  the  same  number  of  trees.  He  would  plant 
12  by  12  feet,  but  before  the  age  of  20  the  number  of  trees  would 
have  to  be  very  largely  reduced.  The  thinning-out  ought  to  be 
done  continuously  and  regardless  of  symmetry.  No  dead  trees 
should  be  replaced  except  when  a  patch  had  been,  for  some  reason, 
cleared. 

Against  the  opinions  of  Gumming,  Gallagher  and  Berkhout, 
we  have  that  of  Mr.  Francis  Pears  to  the  effect  that  ' '  an  acre  of 
rubber  with  50  trees  is  likely  to  prove  more  valuable  than  one 
with  200. ' '     Wickham  advises  40  trees  to  the  acre. 

Planting   Distance  in  Ceylon. 

If  the  estate  is  planted  for  rubber  alone,  all  ideas  of  catch- 
crops  disregarded,  and  a  distance  of  10  by  15  feet  adopted  in 
planting,  the  trees  when  six  years  old  in  Ceylon,  and  earher  in 
richer  soils,  will  certainly  have  their  foliar  and  root  systems  in 
contact.  On  such  an  estate  individual  trees  might  be  stumped  and 
tapped  vigorously  until  they  died,  and  thus  make  room  for  the 
further  development  of  the  remaining  plants.  It  should  be 
mentioned  that  there  are  trees  which  have  been  grown  in  moder- 
ately rich  soil  for  over  twenty  years,  and  though  they  are  still  only 
from  eight  to  ten  feet  apart  they  have  a  circumference  of  from 
forty  to  over  eighty  inches,  and  a  branch  and  foHar  system 
measuring  less  than  thirty  feet  in  diameter.  I  have  frequently 
seen  Hevea  trees  which,  though  planted  the  same  distance  and 
over  10  years  old,  did  not  appear  to  be  too  crowded. 

Joseph  Fraser  (Souvenir,  I.R.J.)  considers  that  in  Ceylon  a 
distance  of  20  by  10  feet  is  the  most  suitable  distance  for  Hevea 


ii8  PARA    RUBBER 

trees.  Later  on,  if  necessary,  they  can  be  thinned  out  to  20  by 
20  feet,  but  he  beHeves  that  with  manuring  on  a  liberal  scale  it  is 
quite  possible  that  the  soil  will  carry  200  trees  to  each  acre  and 
yield  large  crops. 

Distance  in  Planting  and  Checking  of  Growth. 

The  rate  of  growth  is  ultimately  influenced  by  the  distance 
the  trees  are  apart ;  trees  planted  about  ten  feet  apart,  after 
attaining  a  girth  of  about  twenty  inches,  do  not  subsequently 
increase  in  girth  at  the  same  rate  as  do  those  widely  planted.  On  a 
Kadugannawa  estate,  Ceylon,  where  the  trees  are  planted  about 
ten  feet  apart,  those  trees  on  the  boundary  have  continued  to  grow 
in  circumference  after  those  in  the  middle  of  the  plantation  have 
almost  stopped  growing  ;  the  trees  on  this  block  were,  at  the  time 
these  observations  were  made,  about  nine  years  old  and  had  not 
been  regularly  tapped.  It  is,  therefore,  obvious  that  a  per- 
manent distance  of  ten  feet  apart  is  far  too  close  for  Hevea, 
though  many  estates  have  been  so  planted  and  will  require 
systematic  thinning-out  later. 

Many  measurements  have  been  made  by  Ridley  and  Deny 
which  show  the  evils  of  close  planting.  One  lot  of  73  trees  close- 
planted  and  another  of  74  wide-planted,  were  measured  in  1904 
and  again  in  1905  : — 


Aggregate  Girths. 

Aggregate  Increase. 

1904.                 1905. 

73  close-planted 

6686  m.           68-27  m. 

I-4I  m. 

74  wide-planted 

525  m.             58-5601. 

6'4i  m. 

For  each  close-planted  tree  the  average  rate  of  increase 
was  |-  inches,  and  for  the  wide-planted  trees,  3I  inches. 

Ridley  (Bulletin,  July,  1910)  also  gives  measurements  taken 
at  Singapore  over  a  period  of  six  years,  which  show  that  the 
average  annual  increase,  per  tree,  for  the  widely-planted  trees 
was  2j  inches,  against  f  inches  for  closely-planted  trees. 

In  the  report  of  the  Director  of  Agriculture,  F.M.S.,  for 
1910,  the  measurements  below  were  given  of  trees  in  the  Kuala 
Lumpur  plantation  : — 

Close  Planting,  4ft.  by  2ft.         Open  Planting,  25ft.  by  lajft. 

Average  Girth  A,verage  Girth 

at  3ft.  at  3ft. 

1907                            Planted  Planted 

190B                                 2iVin.  3i"8in. 

1909  4i'»™-  6Jin. 

1910  6in.  9fnin. 

The  seeds  were  planted  at  stake. 

The  old  Henaratgoda  trees,  now  about  22  years  old  and 
originally  planted  about  twelve  feet  apart,  measured,  according  to 
Willis,  30  inches  in  girth  in  1897  ;  but  in  1907  the  average  girth 
was  only  about  36^  inches  ;  the  annual  increase  in  circumference 
having  been  much  less  than  one  inch  during  the  last  few  years. 


PARA     RUBBER  iig 

In  the  "Financier"  of  September  27th,  1907,  the  following 
measurements  of  trees  planted  at  different  distances  were  given,  the 
details  being  supplied  from  estates  in  the  Kelani  Valley,  Ceylon  :— 

30-AcRE  Clearing,  Planted  1903  (10  by  10  Feet). 

Tree      No.     1.      2.      3.      4.  5.  6.  7.  8.      9.     10.   Average. 

in.  in.    in.    in.  in.  in.  in.  in.   in.    in.        in. 

January,      1906     . .     6       5I     8f  34  4  3  4J  5J     6       6f       5-3 

January,      1907      ..    11       9     15     6  7  4  7         999         86 

July.  1907     ..    13  lof  18J  7J  8i  5i  8J  iij  lof  loj     io'3 

50-AcRE  Clearing,  Planted  1904  (15  by  15  feet). 

Tree     No.      i.      2.      3.  4.  5.      6.  7.      8.    9.    10.  Average. 

in.  in.  in.  in.  in.  in.  in.  in.  in.  in.    in. 

January,   1906   ■  -   3i  3  3i  3    3|  2f  4i  5i   2*  3i    3-5 

January,      1907     ..7      65  6  10    6  81146          6-9 

July,            1907     ..   loj     8     7|  8 J  i2f  8  iij  14J  5J     9J         9-5 

These  measurements  appear  to  show  that  the  closely-planted 
trees  after  three  years  have  an  average  girth  of  5-3  inches  against 
an  average  girth  of  6-9  inches  for  the  same  aged  trees  on  the  estate 
more  widely  planted.  If  these  figures  represent  what  is  obtainable 
by  a  difference  in  age  alone,  they  are  very  valuable  ;  a  conspicuous 
difference  in  the  rate  of  growth  is  not  usually  expected  during 
the  first  four  or  five  years. 

Systems  of  Planting. 

In  the  planting  of  Hevea  there  are  five  systems  which  may 
be  mentioned  : — 

(«)  Close  planting — permanent ;  {b)  Close  planting  and  thin- 
ning-out ;  (c)  Wide  planting — permanent ;  (d)  Wide  planting 
with  catch  and  intercrops  ;  {e)  Interplanting  with  herbaceous 
and  arborescent  plants. 

What  is  Close  Planting  ? 

To  define  close  planting  is  a  difficult  matter,  and  though  actual 
figures  may  be  quoted,  they  are  subject  to  modification  according 
to  the  physical  and  chemical  properties  of  the  soil,  and  the  nature 
of  the  cUmate  in  which  it  is  proposed  to  grow  the  plants.  The 
term — close  planting — admittedly  implies  the  planting  of  the  trees 
at  a  distance  which  is  not  sufficient  to  allow  of  the  full  development 
of  all  parts  of  the  plant ;  the  latter  is  determined  by  the  natural 
vitahty  of  the  plants  and  the  nature  of  the  soil  and  climate.  Medium 
distance  planting  in  a  poor  cabook  soil,  or  in  a  washed-out  clay, 
above  2,500  feet  in  Ceylon,  would  be  regarded  as  close  planting  in 
a  rich  alluvial  soil  in  the  low  country  of  the  same  island.  The  trees 
should  be  planted  at  such  a  distance  that  they  will  rapidly  develop 
and  take  possession  of  the  whole  of  the  soil ;  their  development  is 
controlled  by  the  amount  of  food  which  the  soil  supplies,  and  it  is 
generally  conceded  that  the  better  the  soil,  and  more  forcing  the 
climate,  the  greater  must  be  the  distance  allowed. 

Disregarding  the  differences  in  quality  of  alluvial,  cabook, 
swampy,  forest  and  chena  land',  from  sea-level  up  to  3,000  feet  in 


120  PARA    RUBBER 

Ceylon,  and  the  allowances  to  be  made  accordingly,  it  may  be 
generally  stated  that  on  a  soil  similar  to  that  at  Peradeniya, 
Ceylon,  a  distance  of  ten  feet  apart,  or  less,  for  trees  of  Hevea 
brasiliensis,  mav  be  designated  as  close  planting  ;  one  of  fifteen 
feet  apart,  as  medium  distance  ;  and  one  of  twenty  feet  apart  or 
over  as  wide  planting.  These  distances  are  subject  to  modifica- 
tion according  to  local  conditions,  and  are  here  given  only  to  pro- 
vide a  basis  for  comparison  ;  it  is  obvious,  for  instance,  that  even 
15  by  15  feet  would  be  regarded  as  close  planting  in  Malaya  and 
Sumatra. 

Advantages  and  Disadvantages  of  Close  Planting. 

The  advantages  of  close  planting  are  that  there  is  a  larger 
number  of  trees  on  a  given  acreage  ;  (2)  the  ground  is  better 
protected  by  the  root  and  foliar  systems,  and  consequently 
expenses  in  weeding  are  greatly  checked,  and  soil  loss  thereby 
reduced ;  (3)  the  rubber  might,  perhaps,  be  harvested  cheaper ; 
(4)  the  cultivation  is  essentially  one  of  rubber  trees  which  pre- 
sumably have  a  higher  value  than  other  trees  of  economic  import- 
ance, and  the  method  of  cultivation  over  all  the  soil  becomes  the 
same  ;  (5)  the  inevitable  proportion  of  poorly-developed,  stunted, 
and  damaged  trees  is  not  as  serious  ;  (6)  it  is  generally  easier  to 
thin  out  a  densely  planted  estate  than  to  interplant  a  widely 
planted  one. 

The  disadvantages  are  ;  (i)  there  may  be  considerable  inter- 
ference in  the  development  of  all  parts  of  the  plant  and  the  resultant 
trees  be  dwarfed  and  lacking  in  vitality  ;  (2)  the  stems  will  tend  to 
become  thin,  long  and  spindly,  and  the  thickness  of  tappable  cortex 
(bark)  reduced  ;  (3)  diseases  are  given  a  greater  chance  of  originat- 
ing and  may  spread  more  rapidly  because  the  parts  of  the  plant 
are  nearer  to  one  another  or  in  more  frequent  contact. 

Distance  Required  by  Tapped  Trees. 

There  is  another  point  which  appears  to  have  been  overlooked 
in  connection  with  this  subject,  and  that  is  the  retardation  in 
growth  which  must  follow  regular  paring  or  tapping.  It  is  no 
exaggeration  to  say  that  most  of  the  old  trees  in  Ceylon  or  Malaya 
were  not  systematically  tapped  until  the  last  few  years,  and  but 
few  estates  can  point  to  acreages  which  have  been  regularly  tapped, 
throughout  successive  years,  from  the  time  the  old  trees  attained 
their  minimum  tappable  size.  Whenever  cortical  tissues  are 
removed  or  mutilated,  the  energy  of  the  plant  is  partly  diverted 
to  the  production  of  new  tissues  in  the  affected  area,  for  the  time 
being  the  intimate  connection  between  individual  vital  structures 
and  that  of  the  latter  with  cells  which  have  less  important  functions 
is  interrupted  ;  such  changes  must  affect  the  future  development 
of  the  plants,  especially  when  of  repeated  occurrence  from  the  4th, 
5th,  or  6th  year  onwards.  In  the  absence  of  any  measurable 
effects  following  the  tapping  of  trees  one  can  only  generalise  and 
state  that  the  sizes  of  trees  so  treated  will  probably  be  less  than 


PARA     RUBBER  121 

those  of  specimens  which  have  never  had  their  bark  so  excised 
and  otherwise  mutilated. 

Original  and  Permanent  Distance. 

It  is  taken  for  granted  that  the  reader  is  famihar  with  the  sizes 
of  Hevea  rubber  plants,  from  their  first  to  their  thirtieth  year,  in 
different  soils  and  climates  ;  the  question  to  discuss  is  whether  the 
original  should  be  the  permanent  distance.  No  one  who  has  seen 
the  uncultivated  thirty-year-old  trees  at  Henaratgoda  can  doubt 
that  such  specimens  require,  at  the  very  least,  a  distance  of  thirty 
to  forty  feet,  if  they  are  to  be  allowed  to  continue  their  growth 
and  maintain  a  healthy  constitution  ;  what  the  required  distance 
will  be  when  they  are  40  to  50  years  old  is  very  difficult  to  predict. 
In  striking  contrast  to  these  are  the  thin,  tall  stems  of  two  to 
four-year-old  trees,  and  the  poor  lateral  spread  of  the  foliage 
when  trees  have  just  reached  the  tappable  size.  Between  the 
first  year  of  tapping  and  that  represented  by  the  old  Henarat- 
goda trees,  is  a  gap  of  nearly  25  years — probably  the  equivalent 
of  a  longer  period  when  the  newly-bearing  trees  are  regularly 
tapped  throughout  successive  years.  I  am  of  the  opinion  that  it  is 
not  advantageous  to  plant,  in  a  clearing,  Hevea  rubber  trees  alone 
at  a  distance  which  they  will  require  when  thirty  years  old  ; 
we  are  dealing  with  a  species  which  does  not,  like  cacao  and 
similar  plants,  attain  the  greater  part  of  its  maximum  size  in 
the  first  six  or  seven  years,  but  with  one  which  continues  to  grow, 
year  by  year,  and  even  when  thirty  years  old,  still  keeps  on 
growing  and  throwing  its  roots  into  new  soil.  Though  Hevea  rubber 
trees  continue  to  grow  in  this  manner  and  the  ultimate  size  attain- 
able can  only  be  roughly  guessed  at  from  our  scanty  knowledge 
and  experience,  yet  we  know  that  when  their  stems  are  only  18 
inches  in  circumference  they  yield  marketable  rubber  in  very- 
satisfactory  quantities.  Four  to  six  years  is  a  long  time  to  wait 
for  the  first  returns,  and  from  a  commercial  standpoint  the  distance 
at  which  trees  can  be  planted,  without  entaihng  undue  interference 
in  general  development,  and  brought  into  bearing  in  their  fourth 
year  onwards,  is  one  worthy  of  every  consideration. 

When  the  trees  are  widely  planted  they  come  into  bearing 
as  early  as  when  closely  planted,  but  there  is  no  very  great 
difference  in  the  dimensions  of  trees  planted  at  widely  different 
distances,  up  to  their  fourth  year ;  the  growth  in  the  first  four 
years  is  not  as  conspicuous  as  in  later  years,  and  even  in  the  richest 
soils  there  is,  despite  ridiculous  statements  implying  the  contrary, 
a  hmit  to  the  root  and  fohar  development  of  Hevea  rubber  plants 
just  as  there  is  to  other  parts  of  plants. 

Thinning-out  Hevea  Trees. 

It  is  rare  that  a  mycologist  recommends  close  planting  and 
thinning-out  at  a  later  date ;  this,  however,  Gallagher  does. 
He  states  that  it  is  better  to  have  too  many  than  too  few  trees,  but 
that  thinning-out  should  be  done  in  the  fifth  and  sixth  years. 
The  roots  should  be  completely  taken  out  and  burned  along  with 


122  PARA     RUBBER 

the  stem  and  every  branch.  He  does  not  definitely  state  that 
the  trees  which  are  to  be  removed  should  be  tapped  to  death  ; 
if  this  is  not  intended  it  is  difficult  to  see  the  advantages,  beyond 
removing  backward  trees,  which  such  a  course  offers.  If  tapping 
to  death  is  intended  it  should  be  borne  in  mind  that  it  takes  one  to 
two  years  to  kill  a  tree  of  the  age  mentioned,  and  by  that  time 
difficulties  may  ari  e. 

Carruthers  (Annual  Report,  1908,)  stated  that  it  would  be 
better  to  pollard  the  trees  and  allow  the  branches  to  grow  beneath 
those  of  the  unpruned  trees,  than  leave  decaying  roots  of  stumped 
trees  in  the  soil. 

Thinning-out  in  Klang. 

The  procedure  adopted  on  some  Klang  estates  is  to  select 
the  trees  which  are  to  be  removed,  saw  them  down  at  a  height  of 
about  eight  feet,  and  drastically  tap  the  remaining  stumps.  In 
one  to  two  years  the  stumps  will  not  yield  paying  quantities  of 
rubber  and  can  then  be  uprooted.  Even  under  these  circumstances 
it  is  surprising  how  the  stumps  develop  ;  even  though  they  are 
densely  shaded  on  all  sides  by  the  fohage  of  surrounding  trees 
several  throw  out  branches  near  the  top,  which  persist  for  a 
considerable  time,  and  would,  if  permitted  to  do  so,  probably 
give  the  stumps  another  lease  of  life.  Often  one  to  two  pounds  of 
rubber  are  obtained  within  a  year  from  the  stump  of  a  six  or 
seven-year-old  tree. 

Close  Planting  and  Available  Tapping  Area. 

The  main  justification  for  closely  planting  Hevea  trees  is  the 
increased  tapping  area  which  is  available  from  the  fourth  year ; 
this  advantage,  however,  only  holds  good  for  a  few  years. 

The  object  of  many  persons  who  planted  this  product  a  few 
years  ago  was  to  place  their  rubber  on  the  market  as  early  as 
possible,  in  order  to  benefit  by  high  prices  and  to  obtain  quick 
returns.  The  results  obtained  by  close  planting  can  be  made  clear 
by  calculating  the  available  tapping  area  from  the  data  previously 
given.  The  table  given  below  shows  the  tapping  area  per  acre 
possible  when  the  plants  are  distanced  from  10  to  20  feet  apart  : — 


Available    tapping    Area 

per  Acre  at  the  End  of 

istance  of  Trees 

Number  of  Trees 

the  4th  or  5th  Year 

in  Feet. 

to  the  Acre. 

in  Square  Inches  ; 
Base  to  5  Feet. 

10  by  10 

435 

522,000 

10  by  15 

290 

348,000 

20  by  20 

169 

130,800 

In  this  table  it  is  assumed  that  the  effect  of  distance  on  the 
rate  of  growth  is  not  apparent  until  the  trees  are  more  than 
4  or  5  years  old  ;  if  after  that  age  has  been  reached  thinning- 
out  has  not  be-;n  done,  the  available  tapping  area  will  increase 
more  rapidly  on  the  widely-planted  areas. 


PARA     RUBBER  123 

From  the  above  table  it  is  obvious  that  by  planting  20  by  20 
feet  the  available  tapping  area  at  the  end  of  the  4th  or  5th  year  is 
reduced  to  about  one-quarter  of  what  it  would  be  if  planted  10  by 
10  feet.  On  an  estate  planted  10  by  10  about  5  per  cent,  of  the 
trees  could  be  killed  out  at  the  end  of  the  4th  year,  and  a  larger 
proportion  dealt  with  likewise  in  succeeding  years,  until  by  the  end 
of  the  8th  year  an  average  of  about  250  trees  per  acre  would  remain. 
The  thinning-out  of  Hevea  trees  is,  however,  an  unsatisfactory 
process,  and  very  few  estates  are  now  being  planted  with  this 
object  in  view.  A  widely- planted  rubber  estate  with  an  inter- 
crop of  cacao  or  coffee  is  apparently  more  valuable  and  less  trouble- 
some than  a  closely-planted  estate  of  rubber  trees  only. 

The  distance  of  10  feet  by  10  feet  suggested  on  the  above 
calculations  is  still  open  to  the  objection  that  the  soil  will,  in 
some  districts,  be  considerably  exposed  during  the  first  few  years, 
but  this  can  be  overcome  by  the  interplanting  of  cuttings  or 
plants  of  Erythrina  lithosperma  (Dadap),  a  species  which  can  be 
made  to  afford  shade  for  the  first  few  years  and  at  the  same  time 
provide  a  rich  mulch  for  the  benefit  of  the  young  Hevea  rubber 
plants. 

The  use  of  the  Dadap  or  Albizzia  stumps  between  young 
Hevea  plants  would,  I  believe,  be  accompanied  by  good  results  in 
very  poor  soils.  The  presence  of  a  young  Dadap  between  every 
two  rubber  plants  would  not  interfere  with  the  growth  of  the 
latter  for  several  years,  as  is  obvious  from  the  previous  considerar 
tions  regarding  the  rate  of  growth  of  the  lateral  root  system. 

On  several  estates  the  rubber  trees  have  been  planted  8  by  8 
feet  and  even  closer,  on  the  assumption  that  half  of  them  would  die 
from  one  cause  or  another  or  could  be  cut  out  when  the  growth 
became  too  dense. 

I  have  endeavoured  to  give  publicity  to  the  views  of  leading 
planters  on  this  very  debatable  subject.  In  view  of  my  having 
been  credited  with  definite  opinions  on  this  subject,  I  now  state 
that  for  planting  Hevea  alone,  I  recommend  a  distance  of  15  by 
15  feet  in  poor  soils  and  20  by  20  feet  in  richer  soils,  thinning-out 
to  be  done  later  as  desired.  Better  still,  I  think,  is  the  use  of 
intercrops  through  Hevea  planted  30  by  15,  30  by  20,  and  30  by 
25  feet  for  Malaya,  Sumatra,  and  Java,  and  20  by  20  feet  in 
Ceylon. 

Pruning    Young    Trees. 

It  is  eminently  desirable  to  maintain  a  clean  undivided  stem 
for  tapping ;  at  least  ten  feet  should  be  reserved  at  the  base 
of  the  tree  free  from  all  branches.  In  the  first  few  years  of  the 
plant's  life,  branches  are  frequently  formed  below  ten  feet  from 
the  base  ;  these  should  be  pruned  back  before  they  grow  to  any 
considerable  size. 

Hevea  brasiliensis  naturally  grows  to  a  tall  slender  tree,  and 
it  remains  to  be  seen  how  by  pruning  or  pollarding  the  young 
plants  an  increase  in  circumference  may  be  obtained  at  the  ex- 
pense  of   the   growth  in   height.      Considering  what   has   been 


124  PARA      RUBBER 

accomplished  with  tea,  where  plants  ordinarily  growing  into  fairly- 
stout  trees  over  twenty  feet  high  have  been  converted  into  small 
bushes  two  to  four  feet  high,  it  would  be  idle  to  predict  the  possi- 
bilities with  Hevea.  This  prevention  of  the  unnecessary  growth 
in  height  may  well  form  the  subject  of  many  experiments.  Wick- 
ham  believes  that  the  ideal  tree  form  for  Hevea  is  three  main 
primary  branches  and  to  each  of  these  three  secondary  branches  ; 
he  recommends  thumb-nail  pruning  as  soon  as  saplings  attairi  a 
clear  stem  of  ten  feet.  Johnson  advises  that  young  trees  which, 
have  been  allowed  to  grow  beyond  the  height  at  which  branching 
is  desired  should  be  pruned  back  to  this  height. 

The  plants  can  be  prevented  from  growing  into  slender  woody 
structures  by  removing  the  terminal  bud  with  a  knife  or  thumb- 
nail, or,  as  is  more  commonly  the  case,  by  pruning  the  terminal 
young  leaves  and  the  enclosed  bud.  If  the  central  bud  is  effectively 
removed,  without  doing  considerable  damage,  the  stem  cannot 
grow  in  height  except  by  means  of  lateral  shoots  ;  these  will  sub- 
sequently require  bud-pruning  once  they  have  attained  the 
required  size.  Buds  which  appear  in  undesirable  places  can  be 
removed  in  the  same  manner,  the  ultimate  result  being  that  a  tree 
considerably  forked  and  supplied  with  abundance  of  foliage  is 
obtained.  The  production  of  woody  tissue  in  the  upper  part  of  the 
tree  is  appreciably  checked,  and  the  girth  of  the  basal  stem  increases 
more  rapidly  than  when  the  tree  is  allowed  to  grow  upwards 
uninterrupted. 

At  Henaratgoda  the  trees  which  have  forked  at  7,  9,  and  11  feet 
from  the  base  show  an  additional  increase  of  30  inches  in  30  years 
or  an  average  of  one  inch,  per  year,  throughout  a  long  and  fairly 
rehable  period.  Young  trees  which  have  been  bud-pruned  in  the 
manner  suggested  above  show  an  increased  rate  of  circumferential 
growth  ;  this  means  the  attainment  to  a  tappable  size  at  an  earlier 
period. 

When  Pruning  Experiments  may  be  Tried. 

This  operation  is  impossible  or  useless  on  old  trees  which  have 
produced  high  woody  stems.  To  cut  off  the  whole  of  the  stem  and 
branches  above  fifteen  feet  would  check  the  growth  of  the  re- 
maining stem,  and  such  a  measure  is  not  recommended.  Old 
trees  treated  in  this  manner  produce  foMage,  but  this  mainly 
testifies  to  their  hardy  characteristics. 

The  stems  of  plants,  when  less  than  20  feet  in  height,  are  more 
suitable  for  such  an  operation  ;  when  12  to  15  feet  high  the 
terminal  bud  alone  can  be  easily  removed  by  thumb-nail  pruning, 
and  lateral  shoots  will  soon  appear  in  the  axils  of  the  leaves  on  the 
"green  wood"  of  the  stem.  The  object  is  simply  to  produce  a 
forked  tree,  the  advantages  of  which  can  be  observed  on  any  young 
rubber  plantation.  If  the  plants  have  been  allowed  to  grow  too 
high  it  is  too  late  to  perform  the  operation. 

The  suggestion  has  reference  only  to  young  clearings  of  Hevea 
rubber,  but,  considering  how  many  thousands  of  acres  are  being 


PARA      RUBBER  125 

yearly  planted  with  this  product,  and  the  possibility  of  appreciably 
reducing  the  long  years  of  waiting,  it  is  important  that  it  should  be 
carefully  considered  and  tried  experimentally  wherever  possible. 
If  the  young  plants  are  made  to  branch  too  much  there  may 
be  a  disadvantage,  as  the  foliage  of  adjacent  trees  may  interfere. 
In  such  case,  however,  were  it  desirable,  the  excessive  branch 
development  could  be  kept  down  by  repetitional  pruning.  It 
should  be  remembered  that  the  lateral  shoots,  induced  by  pruning 
the  terminal  bud,  ultimately  form  stout  branches  which  tend  to 
grow  upwards  and  not  horizontally. 


Dimensions    of    Straight-Stemmed    and    Forked    Trees    in 

Ceylon. 


District. 

Age  of 

Straight- 

stemmed. 

Forked  Trees. 

Average 

Rubber 

Average 

Average 

Differ- 

Trees. 

Girth. 

Girth. 

ence. 

Years. 

Number.  Inches. 

Number 

Inches. 

Inches. 

Galaha 

7 

15 

21-33 

7 

25'I4 

3-81 

Galaba 

10 

14 

2878 

4 

38-37 

9-59 

Kalutara 

2 

94 

rs 

76 

8-3 

0-8 

Matale 

3 

329 

I3"9 

78 

15-5 

1-6 

Kalutara 

li 

14 

4  to  7 

32 

4i  to  7i 

0-4 

Moneragalla 

2i 

250 

6| 

250 

H 

li 

Kalutara 

old 

I 

31 

I 

35 

4 

Do. 

old 

I 

23i 

I 

29 

5i 

Do. 

old 

I 

23 

I 

32 

9  ■ 

Henaratgoda 

30 

ID 

75 

10 

105 

30 

Some  Experiments  in  Pruning. 

The  following  is  an  account  of  one  experiment  carried  out 
at  Peradeniya: — ^Two  plants  of  exactly  the  same  age,  grown  from 
seeds  from  the  same  parent,  were  selected.  In  one  case  the  plant 
was  allowed  to  produce  the  usual  long  and  slender  stem;  the  other 
tree  had  its  terminal  bud  removed  by.  thumb-nail  pruning,  and 
being  unable  to  grow  in  height,  threw  out  ten  lateral  branches. 
The  result  was  the  straight-stemmed  tree  had  only  one  growing 
point  at  the  apex  of  the  stem,  whereas  the  pruned  one  had  ten, 
and  from  each  of  the  latter  were  produced  whorls  of  foliage. 
The  plant  so  treated  had,  four  months  after  pruning,  no  less  than 
200  fully-developed  leaves,  whereas  that  which  had  been  allowed 
to  grow  in  its  own  way  had  only  about  50  leaves.  The  food- 
producing  capacity  of  the  pruned  tree,  as  far  as  the  foliage  alone 
was  concerned,  was  four  times  as  great  as  that  of  the  straight- 
stemmed  one,  and  it  stands  to  reason  that  the  basal  part  of  the 
pruned  tree  would  probably  grow  at  a  quicker  rate.  The  operation 
itself  is  a  gentle  one  and  does  not  partake  of  anything  so  drastic 
as  the  cutting  away  of  the  upper  part  of  young  or  old  trees.  The 
lateral  branches  each  produce  theirown  whorls  of  foliage  as  though 
they  were  members  of  separate  trees,  and  as  they  tend  to  grow 
more  or  less  upwards  may  themselves  require  pruning  at  intervals 
of  three  or  six  months. 


126  PARA    RUBBER 

It  is  therefore  possible  to  lead  to  the  production  of  a  large 
number  of  branches,  and  we  have  next  to  enquire  how  soon  the 
effect  is  obvious  in  the  girth  of  the  stem. 

The  two  plants  referred  to  were  over  one-and-a-half  year  old 
from  stumps,  and  the  forked  one  showed,  four  months  after 
pruning,  a  circumference  of  4f  inches  as  against  4  inches  for  the 
straight-stemmed  tree  ;  this  means  an  increase  of  over  half-an- 
inch  within  six  months  of  the  pruning  operation. 

Growth  of   Forked  Trees   on   Estates. 

The  young  trees  on  various  estates  in  Ceylon  and  the  old  trees 
at  Henaratgoda  indicate  that  an  average  increase  of  about  one  inch 
per  year  may  be  obtained  by  making  them  fork  at  the  proper 
height. 

If  an  average  increase  of  one  inch  per  year  can  be  obtained,  it 
means  that  a  year  is  gained  in  the  first  four  or  five  years  and  a 
minimum  tapping  size  of  20  inches  may  be  reached  in  the  fourth 
year. 

An  interesting  series  of  figures  obtained  in  the  Kandy  District 
showed  that  trees  of  the  same  age,  which  had  branched  at  a  point 
12  to  14  feet  above  ground,  had  an  average  circumference  of  19 
inches,  and  those  which  had  branched  at  5  and  8  feet  from  the 
ground  had  an  average  of  26  inches. 

In  the  Kalutara  District  trees  of  the  same  age,  but  divided  at 
the  base  into  two,  three,  and  four  stems  respectively,  measured, 
in  stem  circumferences  per  tree,  14-4,  i8-i,  and  22  inches  re- 
spectively. In  all  parts  of  the  island  the  increased  circumference 
due  to  forking  of  the  trees  can  be  seen,  and  the  fact  has  even  been 
noted  in  the  annual  report  of  a  prominent  company  largely  in- 
terested in  rubber. 

The  Neboda  Tea  Co.  of  Ceylon,  Ltd.,  in  their  annual  report 
for  1905,  state  that  the  two  tallest  trees  show  the  smallest  girth, 
and  the  shortest  and  well-branched  trees  the  best. 

Tudhope  (Annual  Report,  Aburi,  1909,)  states  that  the  Hevea 
trees,  especially  those  which  have  branched  low,  are  making 
rapid  growth.  Proudlock,  in  his  report  on  rubber  trees  at  Nilam- 
bur,  1908,  after  giving  girth  measurements,  points  out  that  13  out 
of  the  37  trees  measured  have  forked  stems,  and  that  the  ' '  tappable 
girth ' '  is  greater  than  in  trees  unforked.  He  shows  that  the 
average  girths  at  4  feet  of  the  two  or  three  forks  together  is 
greater  than  the  average  girths  of  the  unforked. 

Some   Opinions  on  Pruning. 

Since  I  suggested,  some  five  or  six  years  ago,  that  experiments 
should  be  tried  in  thumb-nail  pruning,  the  subject  has  received 
attention.  My  critics,  however,  are  in  the  main  not  planters  ; 
some — Wickham,  Johnson,  and  Proudlock — favour  the  system, 
but  many  others  do  not.  Experiments  made  under  my  direction 
on  estates  in  Malaya  and  Sumatra  have  demonstrated  that  in 
windy  places  or  on  light  friable  soil  the  system  is  not  to  be  advocat- 
ed ;  on  the  other  hand,  districts  not  frequented  by  strong  winds  and 


PARA     RUBBER  127 

nav  ng  stiff  clayey  soils  appear  to  give  more  favourable  results. 
The  most  important  objection  arises  when  either  too  many  lateral 
branches  are  allowed  to  develop  at  the  same  level  and  thus  make 
the  tree  ' '  top  heavy, ' '  or  when  two  opposite  branches  only  are 
allowed  to  grow,  the  juncture  serving  as  a  receptacle  for  water  ; 
-  n  the  latter  case  decay  sometimes  sets  in  and  the  tree  splits  down 
the  middle.  I  still  think  that  where  climatic  and  soil  conditions 
are  favourable  the  experiment  may  prove  useful  providing  the 
lateral  branches  are  allowed  to  develop  in  positions  consistent 
with  the  symmetry  of  the  tree.  It  is,  however,  a  matter  which 
should  be  left  to  the  direction  of  those  on  the  estate. 

Towgood  (T.A.,  March,  1908,)  states  that  in  thumb-nail  prun- 
ing the  place  of  the  main  stem  is  taken  not  by  true  branches  but  by 
suckers,  very  liable  to  split  off,  and  the  tapping  height  is  fixed  for 
all  time.  He  suggests  that  the  leaves  of  the  saplings  be  removed 
leaving  only  the  stalks,  in  the  axil  of  which  new  branches  will 
arise  if  the  operation  is  performed  before  the  terminal  shoot  has 
made  its  appearance. 

Ryckman  (Jour.  d'Agric.  Trop.  Jan.,  1909,)  suggests  that  in 
ordinary  thumb-nail  pruning  the  equilibrium  between  the  root 
system  and  fohage  may  be  disturbed,  and  that  the  liabihty  to 
disease  is  increased  ;  while  admitting  the  latter,  it  is  difficult  to 
see  the  force  of  the  former  objection. 

Bailey  (Singapore  Free  Press,  April  loth,  1908,)  was  against  the 
system,  as  he  believed  it  to  be  unnatural  and  accompanied  by 
numerous  disadvantages. 

Weeding. 

The  question  of  suppressing  weeds  on  rubber  estates  affords 
ample  opportunity  for  new  suggestions  and  criticisms  of  systems 
now  in  vogue. 

The  only  real  item  of  expense  on  a  large  rubber  estate,  newly 
planted  with  rubber  alone,  is  that  of  weeding.  Annual  reports 
to  hand  give  some  information  of  the  cost  of  weeding  on  well- 
known  properties.  Some  balance-sheets  show  that  weeding  has 
cost  one-third  or  more  of  the  total  cost  (including  clearing  jungle, 
planting,  and  managerial  salaries),  of  a  block  of  land  recently 
opened.  Another  hst  shows  that  to  weed  a  plot  of  100  acres  to 
the  end  of  the  5th  year  cost  ;^55o  ;  while  other  properties  are 
known  which  have  cost  ;£io  per  acre  in  one  year  alone  for  weeding. 
Instances  could  be  quoted  where  the  costs  of  weeding  are  much 
higher,  especially  when  lalang  has  appeared.  On  the  other  hand, 
if  an  estate  is  kept  clean  from  the  beginning,  weeding  should  not 
cost  more  than  75  cents,  (rupee)  per  acre,  per  month  ;  even  this  can 
be  reduced  in  later  years. 

Every  planter  knows  that  the  work  of  weeding  is  one  of  the 
most  important  and  frequently  difficult  tasks  when  deahng  with 
newly-planted  rubber  estates.  If  any  part  of  the  property  begins 
to  biiow  a  green  cover,  trouble  will  assuredly  face  the  planter 
when  dealing  with  his  Weeding  contractors.     This  is  especially  so 


128  PARA     RUBBER 

in  Ceylon,  where  almost  without  exception  European  planters  and 
visiting  agents  are  wedded  to  the  system  of  clean-weeding  estates, 
whether  they  be  of  rubber,  tea,  or  cacao.  To  keep  the  estate  free 
from  weeds  is  the  test  as  to  the  fitness  of  a  planter  to  keep  his  post 
in  Ceylon. 

Planters,  even  in  Ceylon,  are  conv  need  that  it  is  impossible 
to  exaggerate  the  soil  loss  that  must  take  place  when  young 
clearings  are,  year  by  year,  exposed  to  tropical  heat  and  rain,  and 
scraped  by  .weeding  contractors.  Nobody  seems  to  entirely 
like  or  approve  of  the  system.  The  proprietor  knows  t  is  costly, 
the  planter  regards  it  as  his  most  troublesome  task,  and  all  who 
have  studied  the  pros  and  cons  pronounce  it  as  injurious  to  the  soil. 
Why,  then,  is  the  system  continued  ?  The  answer  to  this  question 
is  that  it  is  the  only  system  whereby  labour  can  be  retained,  costs 
kept  near  the  minimum,  and  the  Hevea  trees  made  to  show  the 
most  rapid  growth. 

Alternative  Schemes  in  Cultivation. 

Many  systems  have  been  tried  by  planters  in  Ceylon,  Malaya, 
Java,  Sumatra,  and  Borneo  ;  schemes  have  been  evolved  one 
after  the  other  by  the  writer  and  others  ;  money  has  been  spent  and 
experiments  have  been  carried  out  for  several  years  in  succession  ; 
and  after  all  the  same  questions  crop  up  among  the  planters. 
Most  planters  know,  on  an  estate  with  rubber  trees  only,  often  from 
bitter  experience,  that  there  is  very  little  to  choose  between 
clean-weeding  and  no  weeding  ;  to  attempt  to  weed  only  three 
feet  around  each  rubber  tree  is  a  dangerous  and  generally  im- 
practicable system.  To  allow  any  and  all  weeds  to  develop  will 
retard  the  growth  of  the  rubber  plants.  If  there  are  any  planters 
who  do  not  believe  this,  let  them  try  their  hand  and  make  careful 
measurements  of  the  trees  on  plots  cultivated  on  these  systems. 

The  only  practical  way  out  of  the  difficulty  seems  to  be  to 
interplant  the  rubber  properties  with  additional  crops  which 
will  not  rapidly  run  to  seed  and  in  turn  become  dangerous  weeds, 
or  which  will,  in  course  of  time,  give  some  return  as  a  catch  crop 
before  the  rubber  is  ready  for  tapping.  To  interplant  the  rubber 
saplings  with  Dadap  or  Albizzia  trees,  which  grow  rapidly  and 
will  stand  frequent  lopping,  is  one  good  system,  but,  nevertheless, 
quite  impossible  in  some  countries.  To  interplant  with  cacao, 
coffee,  tea,  tapioca,  tobacco,  etc.,  is  even  better,  providing  the 
required  space  is  allowed  around  each  rubber  tree.  Many  planters 
have  tried  tobacco  and  coffee  in  Sumatra,  tea  in  Ceylon,  South 
India,  and  Java,  tapicoa,  indigo,  coffee,  and  sugar  in  Malaya,  and 
cacao  in  Ceylon,  West  Indies,  Samoa,  and  Java,  in  conjunction 
with  Hevea,  and  though  each  country  frequently  claims  to  be 
satisfied  with  the  results  there  does  not  appear  to  be  much  change 
of  system  in  each  of  the  areas  enumerated,  except  that  Malaya 
appears  to  be  gradually  abandoning  all  catch -crops. 


PARA     RUBBER  129 

System  in  Clean-Weeding. 

Clean-weeding  in  the  tropics,  though  appalling  in  its  effects 
on  the  soil  and  costly  to  the  enthusiasts  accustomed  only  to 
agriculture  in  temperate  zones,  seems,  nevertheless,  to  be  the 
most  desirable  system  from  the  commercial  point  of  view.  Once 
an  estate  is  perfectly  clean  it  should  be  maintained  in  that  condi- 
tion for  aU  time  ;  this  can  be  accomplished  at  far  less  cost,  and 
the  minimum  of  dissatisfaction  to  the  labour  force,  than  any 
system  of  partial  weeding  at  irregular,  opportune  intervals. 
After  having  had  a  fairly  extensive  experience  with  the  various 
systems  in  India,'  Ceylon,  Borneo,  Java,  Sumatra,  and  Malaya, 
I  have  come  to  the  conclusion  that  any  system  other  than  syste- 
matic clean-weeding  is  only  advisable  on  very  steep  ground, 
or  when  an  estate  is  taken  over  in  a  bad,  weedy  condition  ;  these 
circumstances  warrant,  and  sometimes  necessitate,  a  departure 
from  the  system  of  clean- weeding,  at  least  for  some  little  time. 

Clean-weeding  should  be  done  in  a  thorough  and  systematic 
manner.  The  area  weeded  should  be  divided  into  blocks,  I.,  II., 
III.,  IV.,  &c.,  and  each  block  gone  back  upon  and  again  clean- 
weeded  once  every  21  working  days  before  the  area  of  clean- 
weeding  is  further  extended.  In  this  way  the  whole  area  should 
be  gradually  overtaken  without  any  portion  being  allowed  to  fall 
behind. 

Believers  in  this  system  usually  instruct  their  managers  that 
planting  extensions  must  not  be  undertaken  until  the  areas  already 
planted  are  being  regularly  weeded  every  21  working  days  or 
once  every  month. 

Joseph  Fraser,  after  a  long  residence  in  the  East,  states 
(Souvenir,  India-Rubber  Journal)  :  ' '  Many  estates  in  Ceylon  and 
Malaya  have  been  kept  perfectly  clean  from  ftie  first,  for  small 
cost,  with  the  best  results.  In  other  cases  where  weeds  have 
over-run  the  state,  and  especially  where  illuk  (lalang)  has  been 
allowed  to  grow,  the  results  have  been  absolutely  disastrous,  and 
the  cost  of  bringing  the  estate  into  bearing  has  been  enormously 
increased.  The  Passion  flower  plant  and  various  other  palliatives 
have  been  recommended,  and  have  no  doubt  done  good  in  certain 
cases,  but  there  is  only  one  right  and  economical  method  which  is 
to  eradicate  all  weeds  before  they  seed. 

Francis  Pears  believes  that  grass  should  be  avoided  like 
poison.  As  for  sowing  Crotalaria  broadcast  on  a  new  clearing 
with  just  sufficient  timber  heaped  and  burned  for  planting,  it  is 
only  inviting  disaster. 

Cicely   Estate   and   Weeding. 

It  is  only  fair  to  state  that  some  managers  have  been  able 
to  secure  excellent  results  without  attempting  even  regular  weeding 
of  the  estate.  At  the  annual  meeting  of  the  Cicely  Rubber  Co. 
in  1911,  Dr.  S.  Rideal  drew  attention  to  the  yield  from  the  trees? 
10  to  12  years  old,  that  had. never  been  clean  weeded.  When  the 
trees  were  taken  over  in  1905  clean-weeding  was  not  thought  of. 


130  PARA    RUBBER 

and  the  opinion  of  those  who  saw  the  estate  at  that  time  was  that 
it  was  very  much  neglected.  The  undergrowth  was  kept  down 
from  time  to  time  by  scything  and  cattle  had  eaten  it  down  too. 
The  trees  on  this  part  of  the  estate,  nevertheless,  gave  81b.  of 
rubber  each  during  the  year  under  review,  a  crop  quite  as  good 
as  that  from  estates  maintained  in  a  clean  condition  at  all  times. 
The  directors  have  only  recently  decided  to  clean  the  area ; 
subsequent  yields  will  be  watched  with  unusual  interest. 
Opponents  of  weedy  estates  may  think  that  the  excellent  yield  was 
in  spite  of  the  weeds,  and  that  a  much  larger  crop  would  have  been 
obtained  from  similar  aged  trees  on  estates  clean  weeded  from 
the  beginning. 

Cultivation  of  Weed  Killers. 

The  cultivation  of  plants  to  cover  and  kill  ordinary  weeds 
is  quite  distinct  from  that  of  growing  leguminous  plants  to  turn 
into  the  soil  as  green  manure,  though  the  objects  of  both  methods 
are  often  attained  by  growing  the  same  plant. 

Crotalaria,  Desmodium,  Trifolium,  Cassia,  Vigna,  Tephrosia, 
Mimosa,  Soya  bean,  have,  among  the  leguminous  tribe,  been  largeh' 
grown  as  weed  killers  in  Ceylon  and  Malaya  ;  their  sow  rate  of 
growth,  the  protection  they  give  to  porcupines  and  rats,  the  poor 
cover  they  give  to  weeds  and  the  necessity  to  annually  sow  seeds, 
have  brought  them  into  disfavour  ;  much  better  results  have 
been  obtained  with  Kratok — a  species  of  Phaseolus — on  estates 
in  East  Java.  The  wild  passion  flower  {Pw.siflora  fcetida)  has 
been  extensively  used  as  a  weed  killer  in  the  Federated  Malay 
States  ;  it  certainly  keeps  the  weeds — even  lalang — in  check.  It 
grows  very  rapidly,  and  appears  to  keep  back  the  growth  not 
only  of  the  wee^s,  but  also  the  rubber  trees  ;  when  uprooted 
weeds  begin  to  grow  quickly  and  should  be  systematically  attended 
to  from  the  moment  the  Passiflora  is  removed. 

The  Madu  Vine  along  with  the  Pupala  shrub  (T.  A.  March, 
1909)  has  been  recommended  by  a  planter  as  superior  to  Passi- 
flora for  suppressing  lalang.  Mikania  scandens,  a  plant  in  Ceylon, 
was  recommended  (Circular  R.B.G.,  1909,)  for  suppressing  weeds  ; 
the  cultivation  of  this  plant  as  a  weed  killer  is  purely  experimental. 
Very  few  weed  killers  are  systematically  grown  in  Ceylon,  Malaya, 
or  Sumatra,  except  the  land  is,  in  addition  to  being  weedy,  very 
steep  ;  the  use  of  these  plants  under  the  latter  circumstances 
is  more  justifiable. 

Experiments  with  weed  killers  were  carried  out  by  the 
Agricultural  Department,  Kuala  Lumpur.  According  to  Camp- 
bell and  Spring  (Annual  Report,  1909  and  1910,)  four  one-acre 
plots  of  Hevea  were  experimented  with  at  Batu  Tiga  and  the  follow- 
ing results  obtained  : — 


Planted  with  Mimosa,  and  not  weeded  after  it  was 

established . . 
Clean  weeded 

Weeded  three  feet  around  each  plant 
Not  weeded    . . 


.\verage  Girth. 

1908. 

1909. 

igio 

in. 

in. 

in. 

S19 

608 

13-20 

6-75 

1115 

t4-oo 

456 

543 

701 

519 

708 

10-37 

PARA     RUBBER  131 

The  Mimosa  plot  was  much  interfered  with  by  lalang.  The 
not  weeded ' '  plot  was  helped  by  the  fact  that  one  end  was  damp 
and  somewhat  shaded. 

Campbell,  after  growing  many  weed  killers,  concluded  that : 
(i)  As  a  substitute  for  weeding  on  old  land  they  are  a  failure. 
Lalang  and  other  weeds  generally  infest  the  land.  (2)  As  an  aid 
to  weeding  they  tend  to  greatly  reduce  its  cost.  (3)  They  tend 
to  retard  the  growth  of  the  trees  planted  among  them.  This  has 
been  noticed  even  with  nitrogen-producing  plants  like  Mimosa  and 
Crotalaria.  The  question  whether  the  reduced  cost  of  weeding 
compensates  for  the  delay  of,  say,  one  year  in  five  in  reaching  the 
tapping  period  is,  Campbell  admits,  an  open  one. 

Lalang. 

On  neglected  estates  the  tall,  narrow  leaves  of  that  much- 
feared  weed — lalang — soon  make  their  appearance.  Tobacco 
lands  in  Sumatra,  after  being  cropped,  are  allowed  to  develop  in 
lalang  and  secondary  growth.  The  same  happens  with  the  sugar 
lands  in  Java  and  tapioca  estates  in  Perak.  Whether  the  frequent 
sight  of  lalang  has  dulled  my  sense  of  fear  I  know  not,  but  I  cer- 
tainly must  admit  that  I  no  longer  look  upon  it  as  the  terrible 
weed  against  which  organised  effort  is  of  no  avail.  I  have  seen 
thousands  of  acres  of  Hevea  developed  on  old  lalang  grounds  and 
now  thriving  exceedingly  well.  As  already  pointed  out,  many 
planters  are  to-day  selecting  such  land  for  rubber  on  account  of 
the  absence  of  tree  stumps  in  the  soil  and  the  relative  immunity 
from  the  root  fungus  and  white  ants  which  such  a  condition  gives. 
There  is  usually  nothing  wrong  with  the  soil  except  that  a  Cfop  of 
tobacco,  tapioca  or  sugar  may  have  been  taken  from  it  in  past 
years. 

On  flat  land  I  have  seen  an  American  steam  plough  used  to- 
turn  the  soil  over  and  bury  the  lalang.  This  seemed  to  me  to  be 
the  wrong  thing  to  do,  but  as  the  lalang  was  kept  in  check  at  a  cost: 
of  two  guilders  (3s.  4d.)  per  bouw  (if  acres)  per  month  during  the 
first  year,  and  at  a  nominal  cost  subsequently,  I  could  not  seriously 
complain.  On  other  estates  the  land  is  kept  free  from  weeds 
along  the  lines  of  the  rubber  trees  to  a  width  of  six  feet,  and  the 
lalang  between  the  rows  smothered  with'kratok,  or  the  wild  passion 
flower.  If  the  estate  has  ultimately  to  be  clean  weeded  and  is 
completely  under  lalang,  it  will  cost  at  least,  even  by  the  most 
economical  method,  two  guilders  per  month  per  acre  for  the  first 
year,  i|  guilders  monthly  for  the  second  year,  and  one  guilder  for 
the  third  and  fourth  years.  Compare  that  cost  with  the 
combined  cost  of  felling,  clearing,  burning,  and  weeding  on  an 
ordinary  estate  developed  from  forest.  Lalang  does  not  come  out 
as  badly  as  the  average  rubber  investor  imagines  ;  on  many  estates, 
however,  £6  per  acre  have  been  spent  per  annum  in  eradicating 
lalang. 

I  do  not  for  a  moment  wish  it  to  be  thought  that  I  like  lalang. 
I  wish  it  were  not  in  existence,  and  strongly  advise  that  every 


132  PARA    RUBBER 

effort  be  made  to  prevent  it  from  getting  a  hold  on  any  planted 
estate.  But  from  what  I  have  seen  accomplished  in  Java,  Sumatra, 
and  Perak,  on  lands  originally  possessing  only  lalang,  I  no  longer 
regard  it  as  a  weed  beyond  the  control  of  the  planter. 

Lalang  Destruction  by  Spraying. 

One  firm,  interested  in  the  production  of  destructive  chemicals, 
submit  that  the  only  effective  method  of  ridding  land  of  weeds, 
especially  lalang  grass,  is  to  attack  the  roots  with  a  solution  of 
arsenite  of  soda.  Where  the  roots  are  not  more  than  a  foot  below 
the  surface,  and  the  soil  is  fairly  loose,  the  solution  will  find  its  way 
to  the  roots  if  the  ground  is  well  and  carefully  sprayed.  If  the 
grasses  and  weeds  have  been  cut  down  and  removed,  and  the 
surface  so  cleared  that  there  will  be  no  >j^aste  of  solution  upon  the 
rubbish  lying  about,  a  good  dressing  at  the  rate  of  25  gallons  to 
70  or  80  square  yards  (that  is,  80  by  i)  will  be  sufficient  to  kill  the 
roots  without  taking  them  up  ;  the  time  chosen  for  application 
is  when  the  ground  is  moist  with  dew.  The  ground  should  be 
well  sprayed  once,  and  then  again  before  it  has  time  to  dry,  one 
dressing  following  the  other  whilst  the  ground  is  wet.  If  the 
roots  are  more  than  a  foot  down  it  may  be  necessary  to  fork  them 
up  or  to  loosen  the  ground  so  that  the  solution  can  easily  penetrate 
to  them.  It  is  stated  that  to  destroy  young  lalang  by  forking 
costs  at  least  about  $60  per  acre,  whereas  the  cost  of  arsenite  of 
soda  of  sufficient  strength  to  accomplish  this  more  effectually 
upon  an  acre  of  ground  would  only  cost  about  I13  (i  dollar  =■ 
2S.  4d.)  c.i.f.  Port  Swettenham,  Singapore  or  Penang.  Campbell 
(Annual  Report,  igo8)  used  a  i-ioth%  solution  and  sprayed  the 
lalang  ten  times.  The  time  occupied  in  spraying  the  solution  over 
an  acre  would  take  three  men,  with  a  fairly  good  distributing 
apparatus,  from  three  to  four  hours.  There  may  be  cases  where, 
from  the  nature  of  the  ground,  or  the  fact  that  the  lalang  is  so 
deeply  rooted,  that  it  has  to  be  dug  up  and  the  roots  taken  away 
and  destroyed ;  but  even  in  such  cases  many  broken  pieces  of  root 
are  bound  to  be  scattered  over  the  surface.  These  will  grow  again 
if  not  destroyed.  One  spraying  would  be  sufficient  to  destroy 
these  pieces  of  broken  roots,  thereby  using  just  half  the  quantity 
of  solution. 

Ants  or  any  other  vermin  feeding  on  vegetable  matter  in  the 
soil  would  also  be  destroyed.  Merryweather's  have  made  a  special 
feature  of  their  apparatus  for  use  in  spraying  weeds  over  large 
acreages ;  pumps  and  lengths  of  tubing  being  varied  according 
to  the  area  under  experiment.  The  same  apparatus,  and  often 
the  same  chemical,  can  be  used  for  weeds  and  diseases  common 
to  Hevea. 

This  method  of  destroying  lalang  has,  under  the  direction  of 
the  Agricultural  Department  in  Malaya,  been  tried,  and  appears 
to  have  given  encouraging  results.  Experiments  were  also  made 
in  Borneo  and  elsewhere,  but  the  conclusion  finally  arrived  at 
seems  to  be  that  the  sooner  it  is  uprooted,  by  forking,  the  better. 


PARA    RUBBER  133 

Even  when  dealt  with  in  this  manner  coolies  have  to  repeatedly  go 
over  the  ground  to  coUect  broken  fragments  of  roots  lying  on  the 
surface.  The  expense  of  ordinary  changkoling  is  high,  especially 
when  the  roots  are  two  feet  below  the  surface  ;  many  estates  have 
spent  from  £b  to  £8  per  acre  in  removing  lalang,  and  even  then 
have  not  got  the  areas  under  control. 

Changkoling  Advocated. 

Mr.  Alma  Baker,  in  the  India- Rubber  Journal,  September 
5th,  1910,  strongly  advocated  changkoling  everything  once  every 
three  months  from  the  time  of  planting.  "This  system  has," 
Mr.  Baker  states,  ' '  the  following  advantages  : — 

"  I.  It  prevents  all  surface  wash  from  the  beginning. 

"2.  It  enables  the  land  to  retain  more  moisture. 

"3.  The  land  does  not  only  retain  all  the  plant  food  it 
originally  had,  but  has  in  addition  the  humus  derived  from  the 
vegetable  matter  turned  in  four  times  a  year,  Also,  the  turning 
up  of  the  under  soil  renders  readily  available,  through  exposure 
to  the  atmosphere,  a  portion  of  the  otherwise  unavailable  salts. 

"4.  It  forces  the  tree,  by  cutting  the  small  surface  laterals, 
to  root  firmer  and  lower,  and  to  take  its  nourishment  from  cooler, 
damper,  and  richer  soil. 

"5.  It  greatly  helps  in  the  eradication  of  Fomes  and  white 
ants,  as  it  clears  the  land  of  all  small  pieces  of  timber,  at  the  same 
time  opening  up  the  soil  for  the  air  and  sunlight  to  penetrate. ' ' 

Baker  feels  certain  ' '  that  this  system  of  cultivation  will  give  a 
larger  percentage  of  tappable  trees  at  a  given  age  than  any  other. 
Trees  growing  in  land  thus  treated  must  have  a  more  vigorous, 
healthy  and  longer  life  than  trees  grown  in  clean  weeded,  un- 
dulating soils  denuded  year  after  year  of  all  surface  soil  and  humus. 
The  cost  of  changkoling  four  times  a  year  is  not  more  than  ordinary 
clean  weeding.  The  one  thing  that  must  be  absolutely  certain 
in  this  class  of  cultivation  is  your  labour  supply.  This  must  be 
sufficient  to  come  back  on  the  area  changkoled  once  every  three 
months  for  certain. ' ' 

Approximate  cost  -of  changkoling  in  average  land — not 
big  lalang :  a  fairly  low  average  for  this  work  per  man  is  2J  acres 
per  month  of  25  days'  work ;  100  coolies  with  an  outturn  of 
80  per  cent,  (very  low),  constantly  at  work,  will  changkol  200 
acres  per  month,  i.e.,  600  acres  per  three  months." 

Mr.  Baker  does  not  say  whether  the  repeated  destruction 
of  roots  encourages  white  ants  and  Fomes  at  a  later  date  ;  once 
Hevea  trees  have  attained  the  age  of  three  or  four  years  it  is  not 
usually  deemed  advisable  to  more  than  lightly  scratch  the  soil 
even  when  manurial  operations  are  being  carried  out. 

Disc  Harrows  and  Cultivators. 

The  disc  harrow  has  recently  been  tried  in  Java  and  Ceylon  ; 
it  can  be  used  when  the  soil  is  comparatively  dry.  According  to 
Lock  (T.A  ,  Feb.,  1910),  it  disturbs  the  soil  to  a  depth  of  2  or  3 


134  PARA    RUBBER 

inches,  and  can  finish  3  or  4  acres  a  day  ;  each  crop  of  weeds  is 
said  to  be  destroyed  as  fast  as  it  appears.  These  harrows  are  also 
being  used  extensively  in  Province  Wellesley,  if  not  also  else- 
where in  Malaya.  For  similar  purposes  cultivators,  say,  9-tine, 
are  employed,  and  probably  are  more  suitable  for  certain  classes 
of  soil. 

Once  a  lalang  area  has  been  changkoled  or  ploughed  a 
number  of  times,  both  disc  harrows  and  cultivators  may  be 
successfully  used  to  keep  down  the  weeds. 

Root  Pruning. 

The  effect  of  changkoling  on  the  roots  would  be  still  more 
marked  if  systematic  root  pruning  were  adopted,  as  suggested  by 
Mathieu.     He  states  (page  126)  that  : — 

"When  the  roots  have  reached  the  limit  of  their  feeding 
ground  they  cease  to  spread.  They  then  coil  up  and  form  tangled 
masses  through  every  inch  of  the  ground  till,  space  lacking,  they 
cease  to  throw  out  new  feeders. "  ....  At  that  time  he  has 
found  that  a  partial  and  light  cutting  of  the  roots,  at  the  extremity 
of  their  feeding  ground,  renews  them  to  a  wonderful  extent. 
The  opening  of  the  ground  causes  moisture  to  penetrate  deeper  ; 
and  the  roots  strike  downwards  into  new  layers  of  soil.  Thousands 
of  new  rootlets  are  formed.  He  has  tried  this  with  coffee,  and 
only  suggests  it  for  Hevea.  To  carry  it  out  make  a  trench  one 
foot  deep  between  the  row  of  trees  and  10  feet  distant  from  the 
trunks,  merely  turning  the  sod  up  to  the  sides  ;  then  two  parallel 
trenches  one  foot  on  either  side  of  the  first,  but  only  4  inches  deep 
so  as  not  to  injure  the  main  roots. 

It  is  needless  to  add  that  this  is  only  a  matter  for  experiment ; 
it  should  certainly  not  be  adopted  until  the  effect  has  been  accur- 
ately demonstrated  on  isolated  trees. 


CHAPTER  VII. 

CULTIVATION  OF. CATCH  AND  INTERCROPS. 

There  is  a  large  number  of  planting  and  scientific  authorities 
who  believe  in  adopting  a  mixed  cultivation,  whenever  possible, 
because  by  so  doing  they  imitate  nature  closely.  It  is  apparent 
that  different  plants  may  help  each  other,  and  also  that  they  may 
feed  on  different  layers  of  soil  or  draw  to  some  extent  upon  different 
soil  constituents  in  different  degrees.  The  necessity  of  strictly 
imitating  nature  in  cultivation  is  not  obvious  to  the  writer.  On 
the  contrary,  we  ought,  with  all  the  knowledge  and  skill  at  our  com- 
mand, to  considerably  improve  on  the  results  obtained  from 
plants  growing  in  the  wild  state.  There  is  far  more  discord 
prevailing  in  jungle  or  forest  areas  than  one  is  at  first  incUned 
to  admit,  and  it  is  easily  possible,  under  cultivation,  to  eliminate 
many  factors  which  ordinarily  impede  the  development  of  a 
particular  plant.  Further,  one  can  go  so  far  as  to  state  that  if  one 
had  not  in  the  past  resorted  to  most  unnatural  methods  in  cultiva- 
tion, many  products  would  to-day  hardly  be  known.  Take,  for 
instance,  the  tea  bush.  The  plant  which  supplies  us  with  tea 
leaves  grows  to  a  large  bush  or  medium-sized  tree  in  its  native' 
habitat.  Even  on  estates  it  develops,  if  not  interfered  with,  into 
a  tree  of  sufficient  height  and  general  size  to  offer  substantial 
shade  to  cacao  plants.  But  on  tea  estates  this  vigorous  plant 
is  cut  down  to,  say,  two  feet,  nearly  every  year  at  low  altitudes. 
Three  months  later  the  bare  woody  branches  throw  out  leaf-buds. 
The  coolies  pluck  the  leaves  and  continue  this  stripping  every 
ten  days  until  near  the  time  for  pruning.  The  regular  plucking 
of  leaves,  pruning  back  of  the  bush  every  year  or  so,  forking  the 
soil  often  to  a  depth  of  nine  inches  and  thereby  destroying  enormous 
numbers  of  roots,  tramping  daily  over  the  hard  sun-baked  soil 
whence  the  tea  plants  derive  their  food  supplies — these  methods 
are  no  imitation  of  nature's  conditions.  Yet  it  is  upon  some  of 
these  factors  that  the  success  of  tea  under  cultivation  depends. 
I  draw  atention  to  this  point  because  one  so  often  hears  opinions 
being  expressed  to  the  effect  that  Hevea  brasiliensis  in  the  East 
will  not  continue  to  thrive  owing  to  its  being  taken  away  from 
its  native  habitat  and  to  its  being  grown  under  conditions  so 
unlike  those  prevailing  in  the  jungle  whence  the  parents  were 
derived. 

There  are  products  which,  unlike  tea,  must  to  some  extent 
have  conditions  under  cultivation  similar  to  those  prevaiUng 
in  the  forest.  Cacao,  for  instance,  during  its  early  life,  at  least, 
must  have  shade.  CastiUoa  rubber  trees,  which  grow  under  the 
shade  of  higher  trees  in  the  undisturbed  forest,  are  also  said  to 


136  PARA    RUBBER 

grow  better,  during  early  life,  with  a  little  shade  under  cultivation. 
The  adaptability  of  some  tropical  plants  is  sometimes  very  limited, 
whilst  in  other  species  it  is  the  reverse.  Each  tropical  plant  should 
be  studied  from  the  individual  point  of  view.  Hevea  brasiliensis 
is,  fortunately,  a  species  which  compares  very  favourably  with 
even  tea  and  coffee  in  point  of  adaptability.  It  grows  at  sea-level 
to  over  3,000  feet  altitude,  in  swamps,  dry  plains,  and  rocky 
hillsides,  and  in  districts  having  dissimilar  climates.  This 
adaptability  enables  us  to  use  Hevea,  under  cultivation,  in  a 
variety  of  ways  :  [a)  as  a  single  product,  (i)  in  association  with 
more  or  less  permanent  intercrops  of  tea,  cacao  and  coffee,  or  (c) 
with  catch-crops  of  cotton,  tobacco,  chillies,  etc. 

Advantages  and  Disadvantages  of  Subsidiary  Crops. 

The  main  advantages  claimed  for  inter  and  catch-crops  under 
Hevea  are  briefly  :  loss  by  soil  wash  is  checked  ;  the  soil  con- 
ditions may  be  improved  ;  plant  pests  are  sometimes  reduced ; 
revenue  is  obtained  before  the  Hevea  can  be  tapped  ;  and  the 
intercrop  may  prove  useful  when  rubber  no  longer  shows  an 
unusual  margin  of  profit. 

The  main  disadvantages  are  :  the  manager's  attention  and 
the  labour  force  are  diverted  from  the  principal  cultivation — • 
rubber  ;  the  soil  may  become  exhausted ;  the  intercrop  often 
retards  the  growth  of  the  Hevea,  and  has  often  to  be  neglected 
when  Hevea  is  in  bearing  ;  the  intercrop  has  usually  a  short 
life,  and  the  total  revenue  therefrom  is  often  less  than  the 
total  expenditure  thereon.  AH  the  foregoing  advantages  and 
disadvantages  must  be  admitted.  At  the  same  time  it  must  be 
acknowledged  that  mixed  products  usually  have  a  longer  life, 
a.nd  many  of  the  disadvantages  of  intercroping  can  be  overcome 
by  adopting  a  definite  system  of  distance  in  planting. 

Intercrops  and  Diseases. 

There  is  also  another  point  which  is  now  being  appreciated  by 
planters  who  have  lost  a  large  number  of  Hevea  trees  on  forest 
clearings  through  Fomes  and  white  ants  ;  viz.,  the  reduction  of 
losses  through  disease  on  lalang  and  old  coffee  clearings  com- 
pared w  th  those  on  land  previously  in  heavy  jungle. 

The  dangers  attending  new  clearings  of  Hevea  trees  on  land 
rich  in  roots,  timber  and  excess  of  organic  matter,  can  perhaps 
be  mitigated  by  the  adoption  of  a  system  which  appears  to  have 
gained  favour  especially  among  planting  circles  in  the  Dutch 
East  Indies.  On  some  estates  it  is  now  the  custom  to  plant  the 
intercrop  of  coffee  two  or  three  years  before  the  Hevea  trees, 
the  interval  of  time  being  sufficiently  long  to  ensure  decom- 
position of  many  of  the  roots.  The  atmospheric  agencies  and  the 
growing  crop  of  coffee  soon  lead  to  a  reduction  of  organic  matter 
in  the  soil,  thereby  affecting  the  food  supply  of  fungi  Hke  Fomes 

semitostus.      The   disadvantage — deferred   planting   of   rubber 

is  obvious,  but  the  scheme  strikes  me  as  one  which,  in  future,  when 


Photo  by.  i'.  J.  HoUou-ay. 
HEVEA     AND     CACAO,      KEPITIGALLE,       CEYLON. 


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PARA     RUBBER  137 

crops  in  addition  to  rubber  have  to  be  kept  in  view,  may  receive 
more  support  than  it  has  done  during  recent  years.  Any  plant 
which  temporarily  cultivated  will  act  as  a  "  trap  crop ' '  and  lessen 
the  liability  to  disease  of  the  main  crop  should  receive  considera- 
tion. Some  plants — notably  certain  green  manures — used  as 
weed  killers  may  assist  in  the  spread  of  certain  diseases  common 
to  them  and  Hevea  trees  ;  but  this  does  not  appear  to  be  the 
case  with  many  quick-growing  "catch-trap"  crops  at  our  com- 
mand. 

It  must  not  be  surmised  that  Hevea  plantations  established  on 
such  areas  are  immune  from  Fomes  or  equally  dangerous  diseases 
or  pests.  Even  soft  woods  like  kapok  (Eriodendron)  and  Albizzia 
moluccana  will  require  from  three  to  six  years  to  decay,  whilst 
the  stumps  of  hard  timber  such  as  Jak  (Artocarpus) ,  Marabau, 
Eugenia,  and  in  fact  most  of  the  trees  on  old  jungle  land,  will 
remain  for  ten  to  twenty  years  or  longer.  A  large  number  of 
the  smaller  trees  can,  of  course,  be  uprooted. 


Financial   Considerations. 

The  main  reason  why  I  am  inclined  to  urge  the  interplanting  of 
more  or  less  permanent  products  is  that  I  believe  that  long  before 
1920  we  shall,  in  rubber  plantation  companies,  be  far  more  de- 
pendent on  intercrops  for  our  revenue  than  we  are  to-day.  This 
view  was  not  always  logical ;  it  has,  however,  been  made  so  by 
the  events  of  the  last  few  years.  We  now  know  that  there  are 
about  400,000  acres  in  Malaya  and  500,000  acres  in  Ceylon,  Java, 
Sumatra,  South  India  and  Borneo — all  planted  with  rubber  trees. 
Throughout  the  tropical  belt,  and  even  in  Brazil  and  Africa, 
plantation  work  is  being  encouraged.  Within  seven  years  it  is 
quite  possible  that  the  plantation  crop  of  rubber  will  be  treble 
the  amount  we  have  been  in  the  habit  of  receiving  yearly  from 
Brazil.  This  means  that  plantation  rubber  may,  possibly  only  for  a 
limited  period,  be  sold  at  or  below  cost  of  production.  Lt  will 
take  several  years  for  the  trade  of  Europe  and  America  to  accustom 
itself  to  consuming  the  new  crops  of  plantation  rubber,  and  it  is 
only  reasonable  to  anticipate  that  the  history  of  cultivated  rubber 
will  be  somewhat  similar  to  that  of  other  vegetable  products  in 
the  tropics.  It  is  because  I  believe  this  so  thoroughly  that  I  recom- 
mend the  cultivation  of  intercrops  in  association  with  Hevea  ; 
it  is  a  measure  of  protection.  The  cultivation  of  other  crops  under 
rubber,  to  last  more  or  less  permanently,  is  possible  by  adopting 
a  wide  system  of  planting,  say  30  by  25  feet  in  the  rich  soils  of 
Sumatra,  Java  and  Malaya,  or  30  feet  by  20  feet  in  Ceylon  and  South 
India.  This  distance  will  give  a  long  life  for  the  intercrops  of 
tea,  cacao  and  coffee,  which  are  the  principal  permanent  crops 
recommended  for  this  purpose.  It  should  also  be  remembered 
that  one  cannot  abandon  tapping  operations,  temporarily,  on 
Hevea  trees  without  almost  entirely  destroying  the  labour  organi- 
zation on  the  estate,  should  it  ever  be  necessary  to  do  this  when 


138  PARA     RUBBER 

prices  for  raw  rubber  are  below  cost.  Where  the  estate  is  inter- 
planted,  however,  there  would  be  ample  work  for  a  good  part  of 
the  labour  force  with  the  intercrops. 

Intercrops  in  Ceylon  and  South  India. 

There  are  about  230,000  acres  over  which  Hevea  trees  are 
planted  in  Ceylon  ;  about  130,000  acres  are  Hevea  alone,  the 
rest — about  100,000  acres — being  through  cacao  and  tea  and 
various  minor  products.  Tea  is  met  with  as  an  intercrop  in 
Ceylon  at  all  altitudes  between  sea-level  and  3,000  feet  ;  the 
greater  part  of  the  acreage  associated  with  Hevea,  however,  is 
below  1,500  feet.  In  many  cases — and  this  apphes  in  the  main 
to  cacao  as  well — the  Hevea  trees  have  been  planted  out  last 
of  all,  the  result  being  a  very  slow  rate  of  growth  and  a  large 
number  of  vacancies,  the  latter  especially  on  cacao  estates.  Where 
the  Hevea  has  been  planted  at  or  about  the  same  time  as  the  tea 
or  cacao,  the  rubber  trees  grow  more  rapidly.  The  areas  com- 
posed of  cacao  with  Hevea  in  Ceylon  are  mainly  on  estates  between 
750  and  1,800  feet  above  sea-level,  the  Matale  and  Kandy  districts 
being  well  represented  in  this  respect.  The  distance  adopted 
in  Ceylon  is  not  one  which  can  be  recommended  for  richer  soils, 
and  even  in  that  island  much  of  the  tea  will  have  to  be  abandoned 
at  an  early  date  where  the  Hevea  is  planted  closer  than  20  by  15 
feet.  The  cacao  plantations  will  last  considerably  longer,  owing 
to  the  advantages  accruing  to  the  cacao  bushes  when  grown  under 
the  shade  of  forest  trees.  In  the  low-country  districts  of  Ceylon, 
citronella,  sugar,  tapioca,  and  other  minor  products  are  often 
grown  as  catch-crops,  but  these  do  not  cover  very  large  acreages. 

Intercrops  on  rubber  estates  in  South  India  are  met  with 
mainly  at  high  altitudes.  Cacao  is  not  grown  as  an  intercrop.  Tea 
and  coffee — Arabian  and  Liberian — are  the  principal  intercrops 
in  South  India. 

Intercrops  in   Malaya. 

Intercrops  are  not  cultivated  very  largely  in  Malaya  ;  in  fact, 
they  find  least  favour  in  that  area.  Only  about  6  per  cent,  of 
Hevea  is  interplanted  in  the  F.M.S.,  and  16  per  cent,  in  the  Straits 
Settlements.  Coffee  as  an  intercrop  is  gradually  disappearing  on 
account  of  the  rapid  growth  of  the  Hevea  trees  ;  this  can  also  be 
said  of  other  intercrops,  particularly  in  the  F.M.S.  The  following 
statistics  (Report  of  the  Director  of  Agriculture,  F.M.S.,  1910), 
show  the  interplanted  acreages  throughout  the  Peninsula  : — 

Federated  Straits  Kelantan 

Malay  Settle-  and 

States.  ments.  Johore.  Kedah.  Total. 

Rubber  alone 231,797  50,928  38,222  12,011  332,958 

Rubber  and  coffee      5.236  —  • —  —  5.236 

Rubber  and  coconuts     4,106  1,000  2  350  5,458 

Rubber  and  sugar 820  676  —  —  1,496 

Rubber  with  other  crops  ...  .          3,815  7,964  5,292  634  17.705 

Totals 245,774      60,568      43,516      12,995      362,853 


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PARA     RUBBER  139 

Intercrops  in  Sumatra. 
Permanent  intercrops  are  not  numerous  in  Sumatra.  Tea 
is  not  cultivated  in  that  island,  neither  is  cacao  to  any  extent.  I 
beheve  that  the  former  is  now  being  tried,  and  the  latter  is 
practically  hmited  to  about  30,000  trees  under  Hevea  on  Tamiang 
estate.  The  principal  intercrop  is  coffee,  Liberian  being  the  most 
popular  variety.  The  only  shade  given  to  the  coffee  is  that  of 
the  Hevea  tree,  and  this  may,  to  some  extent,  account  for  the 
comparative  failure  of  robusta  coffee  in  that  island.  The 
principal  catch-crop  in  Sumatra  is  tobacco  ;  this  could  be  used 
much  more  than  at  present  if  a  wide  distance  was  permitted  for 
the  Hevea  trees.  The  tobacco  is  ruined  by  the  drip  from 
the  trees  if  the  two  products  are  too  near  each  other. 

Intercrops  in  Java. 

It  is  in  the  island  of  Java  that  one  meets  with  mixed  cultiva- 
tion on  a  large  scale.  There  it  is  not  uncommon  to  find  on  the 
same  estate,  in  addition  to  Hevea,  coffee  (Arabian,  Liberian,  and 
robusta)  cacao,  coca,  pepper,  and  indigo,' as  intercrops,  and  also 
trees  of  cinchona,  nutmeg,  kapok  (Eriodendron),  Ceara,  Castilloa 
and  Ficus  rubber.  Mixed  cultivation  has  undoubtedly  been 
carried  on  to  a  ridiculous  extent  on  many,  estates,  the  soil  being 
frequently  crowded  with  thousands  of  trees  per  acre  of  all  de- 
scriptions and  ages.  On  the  better  estates  it  is  customary  to 
grow  only  one  or,  at  the  most,  two  intercrops  under  the  Hevea, 
coffee  and  cacao  being  the  favoured  products  for  this  purpose. 
Citronella,  sugar,  indigo,  Indian  corn,  beans,  and  tapioca  are  also 
grown  on  several  estates  as  catch-crops. 

Effect  of  Rubber  on  other  Cultivations. 

On  many  estates  the  effect  of  rubber  cultivation  on  the  inter- 
crops is  already  apparent,  especially  where  the  Hevea  is  closely 
planted.  Sooner  or  later  the  Hevea  trees  alone  must  be  in  posses- 
sion of  the  land.  As  in  the  low-country  tea  lands  of  Ceylon  and 
the  sugar  estates  of  Perak,  the  closely-planted  Hevea  tre^s  with 
increased  age  demand  more  soil,  and  prevent  the  intercrops  from 
receiving  the  light  they  require.  In  Sumatra  and  Java  the  old 
coffee  estates  interplanted  with  rubber  will  soon  be  transformed 
into  purely  Hevea  propositions,  and  unless  new  lands  are  planted, 
much  of  the  machinery  used  in  the  preparation  of  coffee  will  be 
iiseless.  In  Sumatran  districts  like  Serdang  and  Langkat  the 
change  will  be  great,  owing  to  the  very  large  acreage  now  under 
Liberian  coffee.  In  five  years  time  the  appearance  of  these  two 
residencies  will  be  considerably  changed,  and  for  the  first  time 
a  forest  cultivation  will  reign.  This  can,  in  future,  be  avoided 
by  adopting  a  wider  distance  in  planting  the  Hevea  trees. 

Distances  when  Intercrops  Grown. 

It  is  not  only  necessary  to  adopt  a  wide  distance  when  per- 
manent intercrops  are  grown,  but  it  is  also  advisable  to  have 


I40  PARA    RUBBER 

a  differential  arrangement  of,  say,  30  by  15,  20  by  10,  or  30  by  25 
feet,  instead  of  an  equal  distance  of  20  by  20,  or  15  by  15  feet,  etc. 
This  is  necessary  in  some  cases  where,  as  with  sugar  and  indigo, 
the  intercrop  requires  much  light.  The  wide  space  in  which  the 
crop  is  planted  should  run  east  and  west,  and  thus  get  the  maxi- 
mum amount  of  light  from  the  time  of  the  sun's  rising  to  that  of  its 
setting.  Furthermore,  an  unequal  distance  permits  of  the  short 
distance  line  being  kept  free  from  intercrops  in  order  that  tapping 
operations  can  be  supervised  as  easily  and  almost  as  effectively 
as  when  only  Hevea  is  grown.  The  planting  of  the  intercrop 
should  always  commence  some  distance  from,  but  be  parallel  to, 
the  hnes  in  which  Hevea  is  widely  planted.  By  this  arrangement 
one  always  has  a  clear  space,  free  from  all  crops,  along  the  short 
distance  lines,  and  a  distinct  gap  along  the  wide  distance  lines  ; 
both  useful  in  supervision  later  on. 

The  annual  leaf-fall  should  be  taken  into  consideration  if  the 
Hevea  trees  are  interplanted  with  other  products,  as  the  leafless 
phase  usually  occurs  when  the  dryness  and  temperature  of  the  air 
are  at  the  maximum,  and  the  intercrops  will  therefore  be  exposed 
to  the  dry,  hot  winds  at  a  time  when  rain  is  not  expected. 

Catch-Crops. 

If  real  catch-crops  are  grown  to  occupy  the  land  from  6  to  12 
months  at  a  time,  care  should  be  taken  not  to  plant  them  too  near 
the  rubber  plants.  A  radial  distance  of  one  to  two  feet  should  be 
allowed  each  year  for  the  growth  of  the  roots  of  the  rubber  trees 
and  catch-crops  should  not  be  planted  within  the  rubber  root  area. 

The  catch-crops  can  be  planted  two,  three,  and  four  feet  from 
one,  two,  and  three-year-old  rubber  trees  respectively.  In  all 
cases  the  foliage  or  ashes  obtained  as  by-products  of  the  catch-crops 
can  be  forked  in  around  the  trees  or  broadcasted  over  the  areas 
which  are  partly  occupied  by  the  rubber  roots. 

As  most  plants  used  as  catch-crops  are  very  exhausting,  it  is 
not  deemed  advisable  to  take  more  than  three  crops  off  the  ground 
when  each  crop  occupies  the  land  for  the  greater  part  of  a  year  ;  in 
some  instances,  only  one  crop  should  be  taken. 

Lemon    Grass    and    Citronella. 

Lemon  grass  gives  a  return  six  months  after  planting,  and 
may  be  expected  to  yield  about  14,000  lb.  of  fresh  grass,  containing 
about  20  lb.  of  pure  oil,  per  acre  per  year,  when  grown  in  open 
free  soil.  The  oil  is  valued  at  2d.  to  8d.  per  ounce,  and  is  obtained 
by  steaming  the  freshly-cut  grass.  A  distilhng  apparatus  is 
required,  and  can  be  kept  in  constant  use  by  the  grass  from  300 
acres.  The  fresh  lemon  grass  contains  'o-65  per  cent,  of  potash, 
0-09  per  cent,  of  phosphoric  acid,  and  0-12  per  cent,  of  nitrogen, 
but  if  the  dried  distilled  grass  is  used  as  fuel  and  the  ashes  for 
manuring  the  rubber  plants,  the  exhaustion  is  considerably 
reduced.  The  plant  is  propagated  from  cuttings.  It  is  being 
cultivated  in  parts  of  Ceylon  and  the  Straits. 


PARA     RUBBER 


141 


Citronella  can  be  cultivated  and  distilled  in  exactly  the  same 
manner  as  lemon  grass,  and  may  be  expected  to  yield  about  50  to 
60  lb.  of  oil  per  acre  per  year.  The  pure  oil  is  valued  at  from  is.  4d. 
to  IS.  lod.  per  lb.  in  Europe  and  America.  Citronella  is  cultivated 
on  rubber  estates  in  Ceylon  and  Java  ;    also  in  parts  of  Malaya. 


Gambier. 

The  leaves  and  twigs  of  this  shrub  [Uncaria  gambier)  yield  an 
extract  used  by  tanners  and  dyers  and  in  medicine.  The  shrub 
grows  to  a  height  of  8  to  10  feet.  Protection  of  the  nursery  against 
heavy  rains  is  necessary,  as  the  seeds  are  very  minute.  Statements 
regarding  the  length  of  time  they  retain  their  vitality  vary,  the 
range  usually  being  from  two  days  to  two  months.  Seedlings  are 
transplanted  when  6  to  8  inches  high  in  holes  7  feet  apart,  with 
the  tip  of  the  seedling  showing  just  above  the  level  of  the  ground  ; 
in  later  stages  it  is  said  to  be  an  advantage  to  heap  the  soil  around 
the  base  of  the  stem.  The  seedling  must  be  protected  from  sun  and 
rain  at  first  by  a  canopy  of  branches.  It  may  be  possible  to  crop 
twelve  months  after  planting,  and  again  at  eighteen  months. 
After  two  years  three  or  four  crops  a  year  may  be  taken.  It  must 
be  understood  that  these  statements  regarding  times  of  cropping 
are  only  approximate.  Cropping  goes  on  throughout  the  whole 
year  over  the  estate.  When  the  branches  are  from  20  to  25 
inches  long,  they  are  pruned  at  about  2  inches  above  their  bases. 
Shears  leave  a  cleaner  and  less  harmful  wound  than  the  knife. 
The  prunings  are  passed  through  a  chaff-cutter  and  are  then 
boiled  for  5  to  6  hours.  The  extract  is  concentrated  to  a  thick, 
nearly  solid  syrup  by  further  heating.  After  cooling,  the  mass  is 
cut  into  cakes,  which  are  dried  by  artificial  heat  or  naturally. 
Upon  a  Sumatran  estate  an  elaborate  installation  of  machinery, 
including  a  vacuum  chamber,  has  been  fitted  up  for  preparation  of 
the  gambier  ;  as  the  installation  is  to  be  extended,  the  crop  must 
be  remunerative. 

Ipecacuanha. 

The  annulated  root  of  Psychotria  ipecacuanha,  a  small, 
shrubby  plant,  co'mes  into  the  market  in  worm-like  masses  6  inches 
long.  This  medicinal  plant  is  a  native  of  South  America,  growing 
in  moist,  shady  places  in  forests.  It  cannot  endure  the  hot  sun, 
and  suffers  much  in  dry  weather  ;  on  the  other  hand,  heavy 
rainstorms  are  fatal,  and  good  drainage  is  necessary.  It  has 
been  grown  with  some  success  on  some  estates  in  Malaya.  It 
can  be  readily  grown  from  cuttings,  and  even  so  small  a  portion 
of  the  root  as  ^V  in.  in  length  may  develop  into  a  fresh  plant. 
The  root  is  prepared  for  the  market  by  drying  ;  this  should 
always  be  done  quickly.  Planting  is  in  rows  four  inches  apart, 
with  two  or  three  inches  between  the  plants.  Cuttings  are  not  so 
satisfactory  for  propagation  as  portions  of  the  roots. 


142  PARA    RUBBER 

Groundnuts. 
Groundnuts  yield  as  a  single  product  a  crop  of  1,500  to  3,000  lb. 
of  nuts  per  acre  in  various  countries,  the  best-yielding  varieties  in 
Ceylon  being  the  ' '  Mauritius ' '  and  ' '  Barbadoes. ' '  The  nuts 
are  valued  at  from  £8  to  £14,  according  to  size,  number  of  seeds  per 
nut,  and  cleanliness.  The  seeds  yield  a  valuable  oil,  equal  to 
olive  oil  in  quality,  and  the  residue  after  extracting  the  oil  is  sold  as 
a  manure — groundnut  cake — containing  y^  per  cent,  of  nitrogen-. 
The  foliage  can  be  used  as  a  green  manure  or  cattle  food,  and  is 
known  as  pea-nut  hay  in  America.  The  leaves  and  roots  contain 
nearly  i  per  cent,  of  nitrogen,  and  when  mixed  with  lime,  form  a 
good  plant  food  for  the  young  rubber  trees.  The  plants  are 
propagated  from  seeds.  The  crop  ripens  in  4  to  6  months,  very 
little  machinery  is  required,  and  there  is  a  good  demand  for  the 
oil  and  cake.  In  the  Philippines  they  are  planted  between  the 
rubber  as  soon  as  the  trees  have  commenced  growing.  They  are 
harvested  in  three  months,  the  crops  being  from  7  to  9  piculs  per 
acre  (T.A.,  Nov.,  1910).  Experiments  are  now  being  carried 
out  by  the  Director  of  Agriculture,  Malaya,  with  this  plant  as  a 
catch-crop. 

Cassava  or  Tapioca. 

There  are  several  famous  Hevea  rubber  plantations  in  Malaya 
which  have  practically  paid  for  all  working  expenses  by  cultivating 
varieties  of  Cassava  as  catch-crops  for  the  first  three  or  four  years. 
On  one  plantation  the  rubber  was  planted  15  by  15  feet  and  the 
cassava  6  feet  apart  at  the  same  time  as  the  rubber.  The  crop  was 
ready  for  harvesting  in  18  months  from  planting.  A  second  crop 
was  taken  off  the  land  before  the  end  of  the  fourth  year,  after 
which  the  cassava  cultivation  ceased  to  be  profitable.  I  have  been 
informed  that  a  crop  of  tapioca  or  cassava  flour  of  i|  to  2  tons  per 
acre  per  crop  is  thus  obtainable.  The  proceeds  from  these  crops 
have  on  several  estates  more  than  paid  for  the  upkeep  of  the  rubber. 
On  one  estate  in  Malaya  cassava  or  tapioca  is  largely  cultivated,  and 
on  one  field,  from  which  very  good  crops  of  this  product  have 
been  taken,  the  six-year-old  Hevea  rubber  trees  have  an  average 
circumference  of  20-21  inches,  the  largest  measuring  33  inches  and 
the  smallest  13  inches  in  girth  at  a  yard  from  the  ground. 

Gallagher  believes  (Str.  Bull.,  Feb.,  1909),  that  if  carefxilly 
handled  and  planted  among  Hevea  distanced  30  by  15  or  25  by 
15  feet,  it  does  not  do  much  harm.  He  saw  a  plot  of  5-year-old 
trees  which  had  not  cost  the  owner  i  cent  for  upkeep,  and  were 
quite  equal  to  other  Hevea  trees  at  that  age  ;  Chinese  had  planted 
the  crop,  manured  the  land,  which  was  previously  in  lalang,  and 
left  it  clean. 

In  parts  of  Malacca  the  cuttings  are  planted  5  by  2|  feet 
apart  (3,000  per  acre),  among  Hevea  distanced  20  by  17I  feet 
(125  per  acre). 

Cassava  thrives  best  in  good  soils,  and  can,  according  to  Lewis 
(Manioc,  by  J.  P.  Lewis,  Government  Agent,  Northern  Province, 
Ceylon),  be  grown  in  districts  in  Ceylon  with  only  14  inches  of 


PARA     RUBBER  143 

rainfall  per  year  or  in  districts  with  over  100  inches  per  year.  The 
plant  is  propagated  from  the  stem,  which  is  cut  into  pieces  about 
twelve  inches  in  length,  each  being  planted  in  a  mamoty  hole  at 
distances  of  3  to  8  feet.  The  yield  in  Ceylon  is  said  to  be  from 
8  to  10  tons  of  tubers  per  acre,  or  from  40  to  80  lb.  per  plant.  The 
cuttings  should  be  planted  in  wet  weather  ;  once  established,  they 
continue  to  grow  even  during  periods  of  severe  drought. 

The  exhaustion  following  the  cultivation  of  cassava  can  be 
partly  overcome  by  the  application  of  manure.  The  growing  crops 
would  for  the  first  three  years  protect  the  soil  and  thus  mitigate 
the  loss  which  invariably  accompanies  the  exposure  of  the  surface 
to  sun  and  rain.  The  tillage  of  the  land  necessary  in  the  cultiva- 
tion of  cassava  is  a  material  benefit  to  the  soil. 

On  several  estates,  owing  to  the  cassava  having  been  planted 
too  near  the  rubber  saplings,  a  considerable  amount  of  harm  has 
been  done.  The  growth  of  the  rubber  trees  should  not,  however,  be 
very  seriously  interfered  with  if  proper  distances  are  adopted. 
Some  object  to  the  inter-cultivation  of  this  plant  because  it  is  the 
same  natural  order — Euphorbiaceae — as  Hevea  brasiliensis. 

Cotton. 

The  Hevea  districts  in  Ceylon  usually  have  a  rainfall  far 
in  excess  of  that  required  for  cotton,  but  in  other  countries  where 
rain  falls  only  during  certain  months  and  where  sufficient  dry 
weather  can  be  relied  upon,  the  prospects  for  cotton  as  a  catch- 
crop  in  rubber  are  somewhat  favourable.  Rain  is  required 
during  the  first  two  or  three  months  after  planting,  and  irrigation 
may  or  may  not  be  required  subsequently.  The  ground  should 
be  lined  in  rows  five  feet  apart  and  the  seeds  sown  at  distances  of 
18  to  20  inches  apart  in  the  rows,  6  lb.  of  seed  usually  being  suffi- 
cient for  one  acre.  Selection  of  seed  is  necessary  to  prevent 
deterioration  from  year  to  year.  Plants  sown  in  September- 
October  may  flower  .in  January,  and  the  first  crop  may  be  picked 
about  six  weeks  after  flowering.  According  to  Mee  and  Willis, 
about  80,000  bolls  give  100  lb.  of  lint  and  200  lb.  of  seed. 

Hevea  rubber  and  cotton  has  been  tried  experimentally  in 
the  dry  Northern  Provinces  of  Ceylon.  The  land  at  the  Experi- 
ment Station  in  that  part  of  the  island  is  relatively  flat  and 
can  be  irrigated.  In  one  experiment  Mr.  Mee  planted  the  rubber 
trees  20  feet  apart  with  irrigation  channels  running  midway 
between  the  trees,  so  that  each  Hevea  rubber  tree  had  an  irrigation 
channel  running  down  10  feet  on  either  side  of  it.  The  cotton 
was  planted  5  feet  apart  between  the  rows  of  rubber,  and  in  the 
first  year  there  might  be  three,  in  the  second  year  two,  and  in  the 
third  year  one,  row  of  cotton  between  adjacent  lines  of  rubber 
trees.  On  an  experimental  plot  planted  on  this  system,  the  Hevea 
rubber  trees  planted  in  October,  1904,  and  at  intervals  up  till 
April,  1905,  showed  in  September,  1906,  a  height  of  8  to  15  feet 
and  a  girth  of  from  3  to  6  inches  ;  the  growth  is  very  satisfactory 
for  a  dry,  irrigated  district. 


144  PARA     RUBBER 

Manila  Hemp,  Sanseveiria,  Etc. 

Manila  is  grown  on  several  East  Java  rubber  estates.  It  is 
a  very  exhausting  crop,  the  whole  of  the  foUage  being  removed 
from  the  soil  by  every  harvest.  Within  i8  months  the  plants 
(Musa  textilis)  are  sufficiently  large  to  afford  good  shade  to  the 
ground.  The  profits  from  this  source  are  not  known  to  the 
writer. 

Sanseveiria,  or  bow-string  hemp,  is  sometimes  grown.  It 
develops  very  slowly,  and  is  not  likely  to  prove  very  remunerative. 

Maize  or  Indian  Corn. 

Two  or  more  crops  per  annum  can  be  obtained  from  this 
product  under  very  young  rubber.  I  have  seen  it  growing  as  a 
catch-crop  in  Java  ;  but  like  most  other  plants  of  this  group,  it 
appeared  to  exhaust  the  soil.  The  seeds  are  planted  in  rows  3  feet 
apart.  They  are  positioned  in  the  lines  2  or  3  feet  apart.  The 
yield  in  East  Africa  is,  according  to  Johnson,  4  to  10  bags  (each 
of  203  lb.),  per  acre. 

Chillies. 

These  are  not  cultivated  extensively  as  a  catch-crop  by  Euro- 
peans in  Ceylon,  though  the  successful  results  obtained  in  India  and 
the  West  Indies  appear  to  warrant  full  consideration.  The  plant  is 
propagated  from  seed,  the  latter  being  put  in  well-prepared 
nurseries.  The  seedlings  are  transplanted  when  2  or  3  inches 
high,  in  rows  3  feet  apart  and  ij  to  2  feet  apart  in  the  rows.  In 
Ceylon  the  planting  generally  begins  in  April,  and  picking  com- 
mences in  June,  and  continues  for  five  or  six  months.  According 
to  Drieberg,  a  chillie  plant,  with  proper  attention,  lives  for  a  year. 
The  produce  per  plant  varies  from  10  to  20  fruits  and  upwards 
per  picking,  and  two  or  more  pickings  can  be  got.  He  further 
states  that  in  Colombo  the  ordinary  market  price  of  fresh  chillies 
may  be  put  down  at  12  cents  per  100  and  dry  imported  ones 
15  cents  per  pound  of  about  750  chillies.  The  chillies  require 
to  be  thoroughly  dried  or  cured  before  being  despatched  to  the 
market.     A  crop  of  1,500  lb.  per  acre  is  considered  satisfactory. 

Pineapples. 
These  are  occasionally  grown  as  a  catch-crop  under  Hevea. 
If  the  rubber  trees  are  distanced  30  by  15  feet  and  pineapples 
are  not  planted  closer  to  any  rubber  tree  than  4  feet,  they  might 
be  used  to  advantage  on  rich  soils.  The  foliage  can  always  be 
returned  to  the  soil  to  reduce  the  exhaustion  consequent  on  the 
cultivation  of  this  crop.  The  plants  flower  in  15  to  18  months, 
thus  ensuring  a  crop  in  the  second  year.  After  the  fourth  year 
cultivation  is  not  advisable.  The  following  estimate  (Strs.  Bull., 
Sept.,  1910),  has  been  given  for  an  estate  near  Singapore  : — 

Receipts,  per  Acre. 

Year.  Pines.  Price  and  Receipts. 

Second  year     2,000  At  2  cents.,    J40 

Third  year 3,000  Ditto  $60 

Fourth  year     2,000  At  ij  cents.,  $30 


PARA     RUBBER  145 

Tobacco. 

Tobacco  as  a  catch-crop  under  rubber  has  not  been  largely 
cultivated  either  in  Ceylon  or  Malaya,  mainly  owing  to  the  atmos- 
phere being  too  moist.  It  is  largely  grown  under  rubber  in  Sumatra 
and  on  a  few  estates  in  Java  and  Borneo.  The  time  taken  from 
transplanting  to  harvesting  varies  from  about  70  to  100  days  ; 
and  dry  weather  is  necessary  towards  the  beginning  of  harvesting 
time.  It  may  yet  be  possible  to  cultivate  either  the  ' '  wrapping, ' ' 
"binding,"  or  "filling"  types  of  leaves  during  certain  seasons 
in  parts  of  Ceylon. 

The  cultivation  of  tobacco  requires  very  careful  selection  of 
soil,  varieties  and  climate,  and  frequently  one  finds  that  it  is  only 
possible  to  grow  one  variety  in  a  particular  area.  The  methods  of 
cultivation  depend  upon  the  variety  being  grown,  but  in  nearly  all 
cases  the  plants  are  first  reared  in  a  nursery  and  are  subsequently 
transplanted.  The  seedlings  are  planted  out,  in  mojst  weather, 
when  about  five  to  seven  weeks  old,  and  are  distanced  according 
to  requirements,  those  for  Sumatra  wrappers  usually  being  close 
together.  When  the  plants  are  i  to  ij  feet  high  the  basal  leaves 
are  removed  and  the  earth  heaped  up  around  the  plants.  At  a 
later  stage  the  flower  buds  are  pinched  off,  and  all  suckers  are 
removed  as  soon  as  they  appear.  The  leaves  are  ready  for  harvest- 
ing when  the  plant  acquires  a  yellowish  colour.  Sometimes  the 
whole  plant  is  cut,  but  in  Sumatra  the  leaves  on  each  plant  are 
plucked  separately  when  ripe.  The  leaves  are  then  carefully 
sorted,  cured,  tied  in  bundles  and  packed.  In  some  countries  this 
cultivation  is  very  profitable,  but  requires  very  careful  supervision 
at  all  stages  and  a  large  working  capital. 

Sugar. 

This  is  planted  for  three  or  more  years  in  succession  under 
Hevea  rubber.  The  latter  is  planted  30  by  15  feet  and  the  sugar 
planted  in  rows  six  feet  apart.  There  is  one  estate  in  Perak  with 
2,000  acres  of  sugar  under  Hevea,  the  total  expenditure  on  the 
estate  having  been  more  than  covered  by  the  revenue  from  sugar. 
From  7  to  11  tons  of  cane  per  acre  per  annum  may  be  expected  as 
a  catch-crop,  and  12  to  18  tons  if  canes  are  grown  alone  on  virgin 
land ;  from  25  to  30  piculs  of  sugar  per  acre  per  annum  may  be 
expected  as  a  catch-crop  under  Hevea  in  Perak. 

Bananas. 

These  are  grown  as  shade  for  rubber  plants  in  some  parts  of 
the  tropics.  Thousands  of  acres  are  cultivated  in  the  West 
Indies.  In  Malaya,  Java,  and  Ceylon,  they  seem  to  give  satis- 
factory yields  on  light  soil..  They  assist  materially  in  keeping 
weeds  down.  They  have  been  reputed  to  pay  £3  per  acre  per 
annum  on  estates  near  towns  in  Malay.  They  are  propagated 
from  suckers,  and  if  grown  alone  are  planted  in  rows  14  by  14  and 
18  by  12  feet  apart.  If  the  foliage  is  not  returned  to  the  soil,  the 
crop  is  very  exhausting. 

J 


146  PARA     RUBBER 

Indigo. 
Turner  states  (Souvenir,  I.R.J.)  that  indigo,  though  looked 
upon  as  exhausting,  has  allowed  probably  the  best  growth  of 
rubber  of  any  catch-crop  we  have  tried.  This  may  be  due  to  its 
being  a  leguminous  plant,  and  even  with  a  heavy  crop  of  stems 
taken  from  it  at  least  twice  a  year,  it  still  appears  to  add  to  the 
growth  of  the  rubber,  which  is  better  than  if  grown  on  clean 
land  with  no  catch-crop. 

Cultivation  of  Intercrops. 

The  successful  and  continued  cultivation  of  intercrops  with 
Hevea  mainly  depends  on  the  distance  the  plants  are  from  one 
another.  The  rapidly-growing  surface  roots  of  rubber  trees  will 
utimately  take  possession  of  the  soil,  and  the  intercrops  of  tea, 
cacao,  or  coffee  cannot  be  expected  to  thrive  unless  the  rubber 
trees  are  widely  planted. 

Tea  as  an  Intercrop. 

If  a  distance  of  20  by  30  feet  or  15  by  30  feet  is  allowed  for  the 
Hevea,  and  the  tea  is  planted  three  to  four  feet  apart  at  the  same 
time  as  the  rubber  trees,  the  intercrop  of  tea  ought  to  last  many 
years,  especially  if  the  narrow  interspace  is  free  from  tea  plants. 
Low-country  tea  in  Ceylon,  Java,  and  India,  must  have  shade,  and 
there  are  many  reasons  why  the  shade  trees  should  be  of  Hevea 
hrasiliensis  instead  of  Albizzia,  Erythrina,  or  Grevillea.  Tea 
planted  under  such  conditions  should  yield  a  small  crop  towards 
the  end  of  the  second  year,  and  give  a  crop  of  350  to  400  lb.  made 
tea  per  acre  per  annum  for  about  ten  years.  After  that  time  the 
Hevea  trees  could,  if  circumstances  warranted  it,  be  pruned  back  in 
order  to  give  the  tea  a  longer  life. 

I  have  seen  several  examples  of  14-year-old  tea  interplanted 
with  6-year-old  Hevea  trees  in  Ceylon,  the  latter  15  by  10  feet 
apart ;  the  tea  presented  a  very  weak,  spindly  appearance,  and 
could  not  be  profitably  plucked.  The  cultivation  of  tea  under 
closely-planted  rubber  is  more  or  less  of  a  catch-crop,  but  several 
estates  are  known  where  the  rubber  is  widely  planted  amongst  tea, 
and  both  are  bearing  and  doing  well.  The  two  products  are  very 
frequently  grown  together  in  Ceylon — especially  in  the  low- 
country  and  in  parts  of  Matale,  Kegalla  and  the  Uva  Province  up  to 
2,600  feet,  and  in  South  India  up  to  3,500  feet. 

Camphor  and  Coca. 
The  desirability  of  growing  camphor  as  an  intercrop  has 
often  been  discussed,  but  so  far  very  few  rubber  planters  in  the 
East  have  given  the  subject  much  attention.  The  plants  can  be 
planted  out  on  lines  very  similar  to  those  adopted  with  coffee. 
A  crop  of  pruned  leaves  and  twigs  cannot  be  expected  before 
two  years  at  least,  and  a  distillation  plant  of  a  simple  type  is 
required. 


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PARA     RUBBER  147 

The  cultivation  of  Coca  (Erythroxylon  Coca)  especially  the 
novo-branatense  variety,  which  is  suited  to  a  hot,  moist  cUmate, 
has  been  suggested.  It  is  a  native  ot  Peru,  and  is  cultivated 
for  its  leaves,  which  jrield  cocaine. 

Cacao  as  an  Intercrop. 

Cacao  planted  in  the  middle  of  the  lines  under  rubber  will 
last  for  several  years.     The  roots  of  these  plants  do  not  as  closely 
ramify  in  the  soil  as  those  of  the  crowded  tea  plants,  though  they 
will  ultimately  have  to  face  the  struggle  for  existence  with  the 
roots  of  Hevea  rubber,  and  will  probably  be  choked  out.     Cacao 
may  be  planted  10  to  20  feet  apart,  and  the  amount  of  soil  on 
good  cacao  estates  which  is  free  from  roots  is  often  very  large,  and 
permits  of  the  growth  of  other  trees  on  the  same  acreage.     Cacao 
under  rubber  will  last  much  longer  than  tea,  and  the  protection 
by  the    Hevea   rubber    trees    against    excessive    exposure   is   no 
doubt  greatly  in  favour  of  the  two  products  being  grown  together. 
In  the  Matale,  Dumbara,  Kurunegala,  Polgahawela,  and  Kandy 
districts  of  Ceylon,  cacao  and  Hevea  rubber  as  a  mixed  cultivation 
is  extending.     Good  results  have  been  obtained  on  Kepitigalla, 
Dangan,  WariapoUa  and  many  other  estates  in  Matale  and  on 
numerous  private  and  public  properties  in  the  above-mentioned 
districts.     The  planting  of  both  products  on  the  same  soil  is  done 
in  such  a  way  as  to  allow  free  root  areas  for  both  species  during 
the  first  five  years,  many  planting  the  cacao  and  rubber  both 
twenty  feet  apart,  so  that  there  will  be  approximately  100  rubber 
and   100  cacao  trees  per  acre.     Though  the  rubber  ultimately 
becomes  the  stronger  component,  it  is  surprising  how  long  both, 
products  can  be  successfully  grown  together.    A  yield  of  one  to 
two  cwt.  of  dry  cured  cacao  per  acre  can  be  expected  annually 
as  an  intercrop  in  Ceylon  ;  more  in  Samoa  and  parts  of  Java.   In  the 
cultivation  of  cacao  under  Hevea  rubber  it  is  essential  that  both 
products  be  planted  at  the  same  time,  as  the  rubber  tree  is  about 
as  strong  as  the  coconut  palm    in   its  root  system  and  quickly 
takes  possession  of  the  soil.     I  am  aware  that  there  are  diseases 
common  to  Hevea  and  cacao,  and  that  some  authorities  recommend 
the  cutting  out  of  cacao  interplanted  with  Hevea.     This  would  be 
of  very  little  use,  seeing  that  caqao  estates  may  exist  in  the  same 
district ;  while  I  imagine  there  would  be   considerable  difficulty 
in  compelling  cacao   planters  to   fell  their  trees  because  Hevea 
plantations  were   liable   to    infection  therefrom ;    or  vice  versa. 
The  best  advice  is  to  control  the  diseases  on  both  plants,  and 
maintain  each  in  good  condition. 

Coffee    as   an    Intercrop. 

In  Java,  Sumatra,  and  at  high  elevations  in  South  India,  coffee 
is  often  grown  between  Hevea  rubber  trees.  In  most  instances  the 
rubber  trees  have  been  interplanted  among  existing  coffee  bushes. 
This  is  especially  so  with  Arabian  and  Liberian  coffee  varieties. 
When  Hevea  rubber  and  coffee  trees  are  planted  at  the  same  time,  or 
the  former  a  few  months  in  advance  of  the  latter,  the  length  of  life 


148  PARA    RUBBER 

of  the  coffee  bushes  is  mainly  dependent  on  the  distance  at  which 
they  and  the  Hevea  trees  are  planted.  With  Hevea  planted  20  by 
20  feet,  two  rows  of  coffee  may  be  planted  six  feet  apart  in  the 
middle  of  the  rows,  the  distance  from  the  rubber  plants  being 
seven  feet  on  each  side.     But,  even  when  planted  at  such  distances, 
the  rubber  soon  shades  the  coffee,  and  the  latter  cannot  be  expected 
to  yield  much  produce  after  the  fifth  or  sixth  year  from  planting. 
The   very   small   crops   obtainable   from   Arabian   and   Liberian 
varieties  under  such  a  system  offers  no  encouragement,  and  these 
varieties  are  now  rarely  planted  as  an  intercrop.     On  most  rubber 
estates  interplanted  with  coffee  the  object  is  to  retain  the  coffee 
until  such  time  as  the  tapping  and  cultivation  of  the  rubber  trees 
demands  the  whole  of  the  manager's  attention  and  the  entire  cooly 
force.      Consequently,  it  has  come  to  be  regarded  on  some  estates 
more  as  a  catch-crop  than  a  permanent  intercrop.      The  variety 
most  suitable  for  this  purpose  appears  to  be  robusta  coffee,  since  it 
begins  to  yield  at  the  end  of  its  second  year,  and  is  expected  to 
yield  large   crops  before  the  sixth  year.    Robusta  coffee,  planted 
alone  in  a  clearing,  may  in  its  third  or  fourth  year  give  from  10  to 
20  cwt.  per  acre.     Among  rubber  it  5aelds  less  per  acre  per  annum 
for    obvious    reasons.     Furthermore,    robusta     coffee     requires 
shade  from  the  commencement,  and  in  Java,  even  though  planted 
among  rubber,  has   to    be  ■  shaded    by    means  of  other  plants, 
"Lamtoro"    being    generally    selected    for    this    purpose.     The 
relative  absence  of  shade  in  Sumatra  may  account  for  the  com- 
parative failure  of  this  variety  up  to  the  present.     Where  it  is 
deemed  advisable  to  make  coffee  a  more  or  less  permanent  inter- 
crop, I  would  suggest  a  distance  of  30  by  25  feet  for  the  Hevea, 
the  coffee  not  to  be   planted  in    the   line  of  the  narrow  space, 
but  as  four  rows,  six  feet  apart,  in  the  30-foot  space.     This  would 
leave  a  clear  space  of  at  least  six  feet  from  every  Hevea  tree,  and 
a  sUghtly  greater  distance  if  the  hues  of  coffee  commence  in  a  row 
parallel  to,  but  3I  feet  from,  the  30-foot  lines.    Already  on  certain 
estates  in  Java  the  robusta  coffee  bushes,  though  only  3  years  old 
have  grown  at  an  astonishing  rate  and  have  had  an  adverse  effect 
on  the  Hevea  trees  planted  20  by  20  feet. 


CHAPTER     VIII. 
SOILS    AND     MANURING. 

During  the  first  few  years  of  active  Hevea  planting  in  the 
East  planters  were  in  the  habit  of  selecting,  whenever  possible, 
the  banks  of  rivers  or  areas  liable  to  inundation  for  the  cultivation 
of  their  rubber  trees.  This  was  due  to  erroneous  advice  originally 
obtained  from  Brazil  and  circulated  among  planters  and  others. 

Consul  Churchill  stated  in  1897,  in  his  report  dealing  with 
the  trade  of  Para,  that  the  rubber  trees  (Hevea)  thrive  best  on 
islands  and  low  ground  near  to  rivers  where  the  banks  are  period- 
ically flooded.  He  went  so  far  as  to  report  that  ground  above 
water  at  all  times  or  that  had  no  drainage  was  not  so  suitable  to 
the  tree. 

Where  Hevea  Thrives  on  the  Amazon. 

This  information  was  widely  read,  and  government  depart- 
ments tendered  advice  accordingly.  Time  and  experience  have 
shown  how  erroneous  the  view  was  that  plantations  should  be 
along  river  banks,  and  not  on  ground  above  water  at  all  times. 
Wickham,  to  whom  the  plantation  industry  owes  so  much, 
repeatedly  pointed  out  the  mistake  made  by  planters  who  were 
acting  upon  advice  based  on  Churchill's  report.  He  states  that  the 
true  forests  of  Hevea  trees  lie  back  on  the  highlands,  where  they 
often  attain  a  circumference  of  ten  to  twelve  feet,  and  an  immense 
height.  He  believes  that  the  trees  seen  by  travellers  on  the 
' '  wet  marginal  river-lands  are  never  well-grown  trees. ' '  They  are 
the  offspring  of  seed  brought  down  from  the  inner  lands  during 
the  rainy  season.  The  soil  of  the  true  Hevea  forests  is  described 
by  him  as  not  being  remarkable  for  its  fertility,  but  for  depth  and 
uniformity  ;  it  is  generally  ' '  a  stiff  soil,  overlying  marl  formation. ' ' 

Pearson  (India  Rubber  World,  August,  1910)  states  that  at 
Manaos,  on  an  estate  which  he  visited,  trees  planted  on  land  well 
above  the  usual  water-level,  but  subject  to  inundations,  apparently 
suffered  no  harm.  Further  up  the  slope,  above  the  high-water 
mark,  were  trees  equally  large  and  healthy. 

He  was  informed  by  the  acting  director  of  the  Para  agricultural 
experiment  station  that  the  railway  from  Para  affords  access  to 
a  tract  of  well-drained  and  healthful  territory,  immune  from  the 
caprices  of  annual  floods.     This  area  is  part  of  the  great  forest 


150  PARA    RUBBER 

system  of  the  lower  Amazon,  and  is  a  typical  rain  forest.  The 
large  size  of  the  Hevea  tree  testifies  to  its  adaptabiUty  and  ability 
to  compete  with  its  neighbours.  There  are  large,  strong,  and  pro- 
ductive trees  planted  in  Para  along  a  railway ;  yet  here  the  soil 
is  poor,  the  trees  are  crowded,  and  have  been  neglected. 

Ule  (Notizblatt  Konigl.  Bot.  Garten,  Berlin,  Bd.  III.  and 
IV.,  1901-4)  found  Hevea  brasiliensis  growing  on  the  flooded 
areas  up  to  the  edge,  but  beyond  were  trees  giving  good  and  rich 
latex,  though  he  could  not  definitely  class  them  as  the  same  species. 

Witt  (Lectures,  Rubber  Exhibition,  1908)  asserted  that  in  the 
state  of  Amazonas  Hevea  brasiliensis  is  to  be  found  only  on  the 
lower  part  of  the  rivers  in  those  regions  subject  to  periodical 
inundations.  Yet  higher  up  country,  on  the  Purus,  Jurua,  etc., 
in  regions  where  there  are  no  inundations,  but  only  very  heavy 
rains,  a  first-class,  though  not  so  good  a  rubber,  is  collected.  On  the 
islands,  where  the  rubber  forests  are  daily  more  or  less  submerged 
by  the  tides,  Hevea  brasiliensis  lives  on  very  low  ground. 

A  United  States  Consul  at  Para,  Mr.  Kerbey  (Special  Consular 
Reports,  vol.  VI.,  1892)  bieheved  that  on  the  river  Purus,  where 
the  flood-plains  were  covered  with  water  from  one  to  three  or 
four  months  in  the  year,  the  trees  3delded  latex  in  abundance, 
while  thriving  trees  of  the  same  sort  not  reached  by  the  floods  did 
not  pay  for  the  trouble  of  tapping  them.  Yet  on  the  lower 
Amazon,  not  only  the  trees  on  the  tide-flats  and  flood-plains 
yielded  latex  in  pajang  quantities,  but  also  those  on  the  high  land, 
because  the  abundant  rains  of  six  months  or  more  in  the  year 
supplied  abundance  of  water  to  the  soil. 

Mathews  (' '  Up  the  Amazon  and  Madeira  Rivers, ' '  1879) 
claims  that,  on  the  Madeira  river,  trees  on  lands  that  are  inun- 
dated only  at  times  3deld  better  than  those  on  very  low  or  on 
elevated  ground. 

Another  observer  (T.A.,  August,  1910),  hailing  from  Bohvia, 
remarks  that  the  best-yielding  Hevea  trees  grow  on  steep  slopes, 
often  between  broken  rocks  ;  yet  in  this  case  one  would  like  to 
be  assured  as  to  the  species. 


Wickham's  Views  Challenged. 

Nevertheless,  statements  to  the  effect  that  Hevea  brasiliensis 
grows  only  or  yields  best  in  regularly-flooded  areas  are  numerous, 
and  making  an  allowance  for  negative  evidence,  the  information 
to  hand  comes  from  such  authoritative  sources  that  one  is  not 
surprised  to  find  that  the  earliest  planters  followed  the  advice 
then  tendered.  One  of  the  strongest  cases  is  that  made  by  De 
Kalb  (India-Rubber  Journal,  July,  1894)  who,  challenging  the 
assertion  of  Wickham  noted  above,  pointed  out  that  both  Von 
Martius  and  Popping  spent  many  years  in  a  study  of  the  flora  of 
the  Amazon,  in  the  course  of  which  they  penetrated  both  high 
and  low  country,  and  their  verdict  was  that  Hevea  brasiliensis 


PARA     RUBBER  151 

occurred  only  in  low,  alluvial  situations.  He  mentioned  also 
that  Bates,  who  spent  seven  years  in  scientific  research  in  the  basin 
of  the  Amazon,  was  most  positive  to  the  same  effect.  De  Kalb 
noted  that  every  tributary  of  the  Amazon  has  been  ascended  by 
explorers,  and  in  accounts  of  the  high  country — except  where 
there  are  local  basins  subject  to  inundation — there  is  no  mention 
of  Hevea  brasiliensis.  His  belief  was  that  Wickham  was  mistaken 
in  his  identification  of  the  species,  the  suggestion  being  that  it 
may  have  been  Hevea  lutea.  Surely  Bates's  statements  do  not 
justify  De  Kalb's  making  such  an  unqualified  use  of  them.  What 
Bates  said  was  that  the  tree  grows  only  on  the  low  lands  in  the 
Amazon  region,  and  that  when  he  was  in  Brazil,  now  about  60 
years  ago,  the  rubber  was  then  collected  chiefly  in  the  islands,  and 
in  the  swampy  parts  of  the  mainland.  Some  of  these  islands, 
of  which  he  had  direct  knowledge,  were  submerged  in  the  rainy 
season.  Bates  did  not  intend  to  make  a  general  statement 
covering  the  whole  of  the  Hevea  areas. 

Origin  of  Erroneous  Views. 

There  is  no  doubt,  to  my  mind,  that  the  advice  regarding 
the  desirability  of  cultivating  Hevea  on  the  banks  of  rivers  can 
be  traced  to  the  custom  of  native  collectors  to  tap  those  areas 
nearest  the  rivers.  The  seringueros  have  to  wait  till  the  rivers 
fall  before  commencing  operations,  and  it  is  natural  that  the  areas 
nearest  the  means  of  transport  should  be  first  dealt  with.  In 
course  of  time  they  must  necessarily  go  further  inland,  when  the 
marginal  trees  have  been  impoverished  or  destroyed,  and  com- 
petition becomes  keener. 

Hevea  not  Constructed  for  Swamps. 

There  are  no  features,  anatomical  or  physiological,  in  any  part 
of  Hevea  brasiliensis  which  even  suggest  that  this  species  is 
especially  suitable  for  wet  land.  The  leaves,  branches,  and  roots 
are  not  in  any  way  xerophytic,  but  conform  to  the  types  commonly 
met  with  among  deciduous  tropical  trees.  Had  this  species 
been  specially  suitable  or  adapted  for  growing  in  wet  lands,  there 
would  have  been  anatomical  characteristics  discernible  without 
the  use  of  a  microscope.  The  fact  that  all  such  features  are  absent 
makes  it  difficult  to  understand  why  botanists  of  repute  should 
have  recommended  the  plant  as  one  specially  suitable  for  wet 
soils  or  river  banks.  It  has,  nevertheless,  proved  itself  capable 
of  adaptation  to  a  remarkable  extent. 

Good   Growth  in   Poor  Soils. 

It  has  been  conclusively  shown  that  Hevea  trees  can  be 
grown  in  soils  relatively  poor  in  physical  and  chemical  properties, 
and  the  following  analyses  of  soils  in  different  parts  of  Ceylon 
(Circular,  R.B.G.,  Peradeniya,  Vol.  III.,  1905)  will  demonstrate  the 


152 


PARA    RUBBER 


composition    of    those    which    have    given    good   results    with 
Hevea : — 


Henaratgoda. 

Peradeniya 

I 

2 

Soils. 

Soil  vmder 

Soil  from 

Udagama 

Old 

Pasture 

Swamps. 

Rubber. 

Tand. 

Mechanical  Composition  : — 

% 

% 

% 

% 

Fine  soil  passing  90  mesh 

27-00 

59-00 

20-00 

26-00 

Fine  soil  passing  60  mesh 

20-00 

36-00 

28-00 

28-00 

Medium  soil  passing  30  mesh 

9-00 

i-oo 

14-00 

21-00 

Coarse  sand  and  small  stones 

44-00 

400 

38-00 

loo-oo 

25-00 

100-00 

100-00 

lOO-OO 

Chemical  Composition  : — 

Moisture          

4-000 

5-600 

1-200 

1-600 

Humus  and  combined  water . 

9-200 

20-400 

7-800 

7-000 

Oxide  of  iron  and  manganese 

s     8-400 

I -200 

2-800 

2000 

Oxide  of  alumina 

12-215 

5-232 

4960 

6-315 

T.ime 

o-o6o 

0-050 

0-040 

o-o6o 

Magnesia 

0086 

0-115 

0057 

0-072 

Potash              

0-092 

o-o6r 

0-046 

0-038 

Phosphoric  acid 

0-038 

0-064 

0-031 

0.031 

Soda 

0095 

0-182 

0-046 

o*o8o 

Sulphuric  acid 

Trace 

0-048 

0-007 

Trace 

Chlorine 

0-014 

0-048 

0-004 

0-004 

Sand  and  silicates 

65-800 

67-000 
loo-ooo 

83-000 

82-800 

roo-ooo 

loo-ooo 

loo-ooo 

Containing  nitrogen    . . 

0134 

0-448 

0-154 

0-134 

Equal  to  ammonia 

0-163 

0-544 

0-187 

0-163 

Lower  oxide  of  iron 

NU 

Much 

Trace 

Fair 

Acidity 

Faint 

Much 

Much 

Much 

Citric  soluble  potash  . . 

o-oo6 

0-009 

0005 

0-004 

Citric  soluble  phosphoric  acid 

Trace 

NU 

Trace 

Trace 

Hevea  Rubber  Soils  in   Ceylon. 

The  extension  of  Hevea  rubber  cultivation  in  various  parts  of 
Ceylon  is,  in  a  general  way,  an  indication  of  the  suitability  of  the 
soil  and  climate  for  this  product  ;  it  is  therefore  of  importance  to 
dwell  upon  the  soil  characteristics  in  some  of  the  more  promising 
districts,  though  these  points  should  be  considered  in  conjunction 
with  the  climatic  factors  for  the  same  areas. 

The  soils  in  which  rubber  is  cultivated  in  Ceylon  are  relatively 
poor  from  a  chemical  standpoint.  The  organic  matter  and  com- 
bined water  vary  from  about  2  to  20  per  cent.,  the  potash  from 
0-03  to  0-04  per  cent.,  phosphoric  acid  from  o-oi  to  o-i  per  cent., 
and  the  nitrogen  from  o-i  to  0-5  per  cent.  But  it  has  been  proved 
beyond  doubt  that  the  physical  and  climatic  characteristics  often 
outweigh  any  advantages  of  richness  in  chemical  properties. 

The  large  tracts  of  land  in  the  up-country  districts  which  are 
richest  from  a  chemical  standpoint  cannot  be  included  in  the 
Hevea  zone  of  the  island  on  account  of  unfavourable  climatic 
conditions. 


PARA     RUBBER  153 

The  following  notes  and  analyses  of  Ceylon  soils  are  largely 
taken  from  a  circular  (R.B.G.,  Circular  No.  6,  1905),  dealing 
with  this  subject. 

Cabooky  Soils,  Ceylon. 

Cabook. — The  cabook  soils  are  met  with  as  local  areas  in  many 
districts.  They  are  usually  inferior  from  a  chemical  and  physical 
standpoint,  though  in  many  cases  the  growth  of  the  rubber  trees 
appears  to  be  satisfactory.  Such  soils  usually  show  a  small  per- 
centage of  organic  matter,  potash,  phosphoric  acid,  and  lime.  One 
analysis  shows  only  8  per  cent,  of  organic  matter  and  combined 
water,  0-085  P^r  cent,  of  potash,  o-oio  per  cent,  of  phosphoric 
acid,  o-o6o  per  cent,  of  lime,  and  0-128  per  cent,  of  nitrogen. ' ' 

Alluvial  Soils,  Ceylon. 

' '  In  physical  properties  these  soils  are  usually  good,  and  the 
amount  of  sediment  periodically  deposited  during  floods  adds 
considerably  to  the  chemical  richness  of  the  soil.  They  are 
largely  composed  of  the  lighter  materials  carried  down  in  suspension 
by  moving  water.  The  particles  are  very  fine,  most  of  them 
passing  a  60  mesh.  This  matter  is  arrested  and  precipitated 
all  along  the  bank  of  the  river  during  flood  time.  During  heavy 
floods  very  large  quantities  of  matter  are  often  deposited  along 
the  banks,  but  they  are  often  of  a  coarser  nature  due  to  the  higher 
speed.  The  particles  which  go  to  make  up  an  alluvial  soil  may 
have  been  brought  from  considerable  distances  ;  they  constitute 
the  fine  parts  of  soils  liable  to  wash  within  the  drainage  area  of  the 
river. ' ' 

One  analysis  shows  about  11  per  cent,  of  organic  matter  and 
combined  water,  0-130  per  cent,  of  lime,  0-162  per  cent,  of  potash, 
0-076  per  cent,  of  phosphoric  acid,  and  0-230  per  cent,  of  nitrogen. 
The  soils  are  usually  good,  and  we  know  that  Hevea  grows  exceed- 
ingly well  in  such  soils,  and  has  continued  to  thrive  therein  for 
over  twenty  years  in  the  Peradeniya  District. 

Swampy  Soils,  Ceylon,   and  Drainage. 

The  cultivation  of  rubber  in  such  areas  has,  during  the  last 
year  or  so,  shown  a  considerable  increase.  Providing  the  draining 
and  liming  of  the  soils  are  efficiently  carried  out,  there  seems  no 
reason  why  continued  satisfactory  growth  should  not  be  obtained 
on  such  land.  The  drainage  should  be  very  thorough,  so  as 
to  allow  of  a  good  percolation  of  air  and  water  through  the  other- 
wise sour  soils.  In  some  cases  each  rubber  tree  should  have  a 
separate  drainage  system,  the  drains  being  two  or  more  feet  wide 
and  3  to  4  feet  deep,  the  material  from  them  being  heaped  up  near 
the  rubber  tree.  In  other  cases  each  line  of  rubber  trees  may  be 
separately  drained.  When  the  drains  are  sufficiently  large  and 
the  soil  from  them  is  heaped  around  the  rubber,  a  dry  soil  is 
ultimately  obtained  in  areas  which  have  hitherto  been  too  swampy 
for  any  cultivation  except  paddy. ' ' 


154  PARA    RUBBER 

One  analysis  of  a  swampy  soil  shows  it  to  contain  20-4  per 
cent,  of  organic  matter  and  combined  water,  0-05  per  cent,  of  lime, 
o-o6i  per  cent,  of  potash,  0-064  per  cent,  of  phosphoric  acid,  and 
0-448  per  cent,  of  nitrogen.  Such  an  analysis  indicates  a  chemical 
richness  in  organic  matter  and  nitrogen  which  rarely  obtains  in 
low-country  districts,  and  strongly  reminds  one  of  the  soils  at 
high  elevations  in  Ceylon.  It  is  to  be  regretted  that  the  area 
of  such  rich  land  in  the  low-country  is  small,  and  the  above  analysis 
is  certainly  encouraging  to  planters  who  have  such  swampy  soils 
capable  of  being  effectively  drained  and  made  sweet  by  the  applica- 
tion of  lime  or  by  burning. 

Treatment   of   Swampy    Soils. 

In  the  Straits  Settlements  and  Federated  Malay  States  and  in 
parts  of  Ceylon  drained  swamps  have  been  proved  to  grow  Hevea 
rubber.  In  the  former  place  large  sums  of  money  have  been 
spent  in  providing  good  canals  for  the  free  circulation  of  water 
through  rubber  estates  near  the  coast. 

' '  Swampy  soils  are  usually  in  a  very  fine  state  of  division,  a  con- 
dition which  may  prevent  the  soil  being  aerated,  and  to  some  extent 
may  hinder  the  free  oxidation  of  the  humus.  Owing  to  the 
extremely  fine  state  of  division  the  soil  can  retain  large  quantities 
of  water,  due  to  the  particles  being  in  such  close  contact  with  one 
another  that  they  form  a  very  large  number  of  capillary  tubes  which 
become  full  of  water.  Again,  such  a  soil  may  suffer  during  periods 
of  drought,  as  it  is  difficult  to  get  the  air  out  of  the  capillaries.  A 
water-logged  soil  is  usually  cold  and  therefore  generally  unsuitable 
for  cultivation,  unless  it  can  be  modified  both  physically  and  chemi- 
cally. One  of  the  chief  aims  in  reclaiming  such  land  is  to  have  the 
soil  well  drained,  in  order  that  the  superfluous  water  may  be  carried 
off  and  the  air  drawn  through  the  soil. 

' '  Burning  has  been  tried  on  peaty  soils  at  high  elevations,  and 
the  results  are  satisfactory.  Paring  the  surface  and  collecting  into 
heaps  and  then  burning  has  also  proved  successful.  The  heat 
should  not  be  allowed  to  become  too  great,  and  should  just  be 
sufficient  to  char  the  vegetable  organic  matter  ;  the  heaps  should 
then  be  distributed  over  the  surface.  There  is  a  loss  of  nitrogen 
and  organic  matter,  but  the  physical  condition  of  the  soil  is  im- 
proved, and  the  potash  salts  are  converted  into  carbonates  which 
are  useful  for  the  neutralization  of  the  free  acids  present.  After 
burning,  the  potash,  &c.,  is  in  a  much  more  available  condition. 

' '  Opening  up  of  swampy  soil  by  the  addition  of  sand  or  gravel 
has  been  tried,  but  this  is  expensive.  Liming  is  very  beneficial  for 
such  soils,  as  it  not  only  opens  them  up  but  also  neutralizes  the  free 
acids  present,  and  thus  gives  a  freer  action  to  nitrifying  organisms. 
The  addition  of  lime  frees  the  potash  from  the  double  salts  by 
double  decomposition,  and  makes  the  mineral  plant-food  generally 
more  available.  Swampy  soils  are  usually  deficient  in  mineral 
plant-food,  and  should  have  occasional  dressings  of  potash  and 
phosphatic  manures,  basic  slag  and  sulphate  of  potash  or  kainit 
being  considered  suitable. ' ' 


PARA     RUBBER  155 

Johnson  recommends  for  drained  swamps  or  land  previously 
Tvater-logged,  that  slaked  lime  at  the  rate  of  2,000  lb.  per  acre 
be  applied. 


Hevea  Rubber  Soils  in  various  Ceylon  Districts. 

In  order  to  give  some  idea  of  the  composition  of  the  soils  of 
typical  rubber  districts  in  Ceylon,  it  is  necessary  to  draw  inferences 
from  many  analyses.  The  districts  known  as  Kelani,  Kalutara, 
Kegalla,  Matale,  Peradeniya,  Kurunegala,  Ratnapura  and  Passara 
are  of  considerable  importance,  and  the  information  given  in  the 
<;ircular  previously  referred  to  is  here  quoted. 

Kelani   Valley  District. 

According  to  Messrs.  Ferguson's  "Ceylon  Handbook  and 
Directory,"  there  were  about  32,507  acres  planted  in  rubber 
alone  in  August,  1910,  in  addition  to  nearly  25,000  acres  inter- 
planted  with  tea,  etc.  The  abundant  rainfall  and  high  tempera- 
ture, together  with  the  moderately  good  soOs  in  the  Kelani 
district,  seem  very  suitable  for  Hevea. 

"Mechanical  characters. — The  mechanical  composition  of  the 
soil  is  moderately  good  ;  generally  14  to  35  per  cent,  passes  through 
a  90  mesh,  20  to  40  per  cent,  through  a  60  mesh,  and  3  to  8  per 
■cent,  through  a  30  mesh  ;  sand  and  small  stones  constitute  30  to 
60  per  cent,  on  an  average.  The  plants  are  mainly  dependent  upon 
the  finely-divided  soil  particles  for  their  food  supplies,  and  therefore 
the  amount  which  passes  through  the  90  mesh  is  of  the  greatest  im- 
portance. Some  soils  which  are  very  finely  divided  are  not  so  well 
suited  for  cultivation  as  coarser  types,  the  latter  frequently  allowing 
of  a  quicker  and  more  complete  circulation  of  air  and  water  in  the 
soil.  The  retentive  power  of  moisture  of  the  soils  depends  upon  the 
physical  properties  and  the  amount  of  organic  matter  present. 
This  variation  for  the  Kelani  soils  is  from  2  to  6  per  cent. :  i.e., 
every  100  lb.  of  air-dried  or  sun-dried  soil  can  retain  from  2  to  6  lb. 
of  water. ' ' 

Chemical  properties. — The  percentage  of  chemical  ingredients 
is,  relatively  speaking,  rather  low  when  compared  with  soils  at 
higher  elevations.  In  some  cases  the  percentages  of  organic 
matter  and  nitrogen  are  satisfactory.  The  organic  matter  varies 
from  8  to  13  per  cent.  ;  the  nitrogen  from  0-05  to  0-2  per  cent.  ; 
the  lime  from  0-05  to  0-15  per  cent.  ;  the  magnesia  from  0-05  to 
0-35  per  cent.  ;  potash  from  0-05  to  o-2  per  cent.  ;  and  the 
phosphoric  acid  from  traces  to  0-07  per  cent.  In  some  cases  the 
high  percentages  of  organic  matter  and  potash  are  exceptional, 
and  do  not  represent  the  general  characters  in  the  Kelani  District. 
The  figures  here  quoted  indicate  the  general  variation  in  the  pro- 
portions of  the  ingredients  which  may  be  expected  in  the  district ; 
they  do  not  represent  the  maximum  and  minimum  compositions. ' ' 


156  PARA     RUBBER 

Kegalla  District. 

The  Kegalla  district  might  also  be  considered  in  connection: 
with  the  Kelani,  as  the  soil  and  climate  appear  equally  suitable  for 
Hevea  rubber.  According  to  the  Ceylon  Handbook  there  were  in 
August,  1910,  15,500  acres  of  rubber,  either  alone  or  interplanted. 
Good  growth  has  been  obtained  in  clearings  only  10  and  18  months 
old  on  the  Mabopitiya,  DickelUa,  Waharaka,  Parambe  and  other 
estates  in  this  district,  and  the  tapping  of  trees  from  12  years 
upwards  on  Yataderiya  and  Undugoda  estates  has  been  accom- 
panied by  profitable  yields.  On  many  of  the  estates  in  the  Kegalla. 
district,  Hevea  rubber  is  interplanted  among  tea. 


Kalutara  and  Galle  Districts. 

During  the  year  1910  the  acreage  under  Hevea  rubber  in  the 
Kalutara  district  was  largely  increased.  The  Ceylon  Handbook 
showed  in  August,  1910,  33,447  acres  in  rubber  alone,  11,606  acres 
in  rubber  planted  through  tea,  and  50  acres  in  coconuts.  During 
and  since  1906  a  considerable  acreage  of  new  land  has  been 
planted,  but  it  is  not  thought  that  very  much  more  tea  will  be 
planted  up  with  rubber. 

South  of  Kalutara,  in  the  Galle  District,  soils  of  similar 
character  are  met  with  and  swamps  frequently  occur.  In  August, 
1910,  no  less  than  8,037  a-cres  were  then  in  Hevea  rubber  alone, 
and  2,370  acres  interplanted  with  tea. 

Mechanical  Composition. — ' '  The  soil  analyses  show  a  slightly 
coarser  texture  than  those  examined  from  the  Kelani  Valley  ; 
usually  from  11  to  28  per  cent,  passes  through  the  90  mesh,  16  to 
40  per  cent,  through  the  60  mesh,  4  to  10  per  cent,  through  the  30 
mesh,  and  sand  and  small  stones  form  from  30  to  70  per  cent,  of 
the  soil.  The  retentive  power  of  moisture  is  very  similar  to  the 
Kelani,  varying  from  2  to  6  per  cent. ' ' 

Chemical  Composition. — ' '  The  organic  matter  shows  a  varia- 
tion similar  to  that  in  the  Kelani  Valley  soils  ;  the  general  range  is 
from  7  to  15  per  cent.,  and  the  same  can  be  said  about  the  nitrogen, 
which  varies  from  o-i  to  0-15  per  cent.  This  is  of  course  excluding 
swampy  areas,  which  we  have  seen  to  be  very  rich  in  organic 
matter  and  nitrogen,  and  alluvial  soil  such  as  that  quoted  below. 
The  potash  varies  from  0-04  to  02  per  cent,  and  usually  shows  a 
relation  to  the  amount  of  magnesia,  both  being  derived  from  the 
decomposition  of  double  silicates.  The  phosphoric  acid  varies 
from  a  trace  to  o-o6  per  cent.,  and  this  low  percentage  is  common 
in  most  Ceylon  soils.  The  lime  varies  from  0-03  to  0-15  per  cent, 
and  the  magnesia  from  0-04  to  o-2  per  cent. 

Another  district  in  which  there  has  been  extensive  planting 
in  rubber  is  the  Galle  district.  Here  in  August,  1910,  there  were 
8,037  acres  in  rubber  alone  and  2,370  acres  with  tea.  The  soils 
of  this  district  were  not  included  in  the  above  survey. 


PARA     RUBBER  157 

'  Matale  District. 

In  the  Matale  district  there  were  in  August,  1910,  some 
9.753  acres  of  cacao  interplanted  with  rubber,  4,589  acres  inter- 
planted  with  tea,  and  15,326  acres  in  rubber  alone. 

It  is  well  known  that  the  Matale  district  contains  some  very 
old  Hevea  trees  that  are  now  being  tapped,  and  that  large  areas 
have  been  planted  in  association  with  cacao  and  tea  as  well  as  a 
single  product.  Trees  at  an  elevation  of  2,300  feet  are  being 
tapped  in  that  district. 

"  The  soils  characterising  the  Matale  district  are  somewhat 
similar  to  those  near  Peradeniya. " 

Mechanical  Composition. — ' '  The  soils  from  the  Matale  district 
are  on  an  average  in  a  better  state  of  division  than  those  in  the 
districts  previously  dealt  with,  usually  from  15  to  30  per  cent, 
passing  through  a  90  mesh,  14  to  25  per  cent,  through  a  60  mesh, 
and  3  to  7  through  a  30  mesh.  Sand  and  small  stones  may  form 
from  40  to  60  per  cent,  of  the  soil.  The  retentive  power  for  moisture 
of  air-dried  soil  does  not  show  a  very  great  variation,  and  is  from 
3  to  6  per  cent. ' ' 

Chemical  Composition. — "The  organic  matter  usually  varies 
from  8  to  14  per  cent,  and  the  nitrogen  from  o-i  to  0-2  per  cent.  ; 
the  lime  from  o-o8  to  0-2  per  cent.  ;  the  magnesia  from  0-05  to 
0-25  per  cent.  ;  the  potash  from  0-03  to  0-25  per  cent.,  and  the 
phosphoric  acid  from  o-oi  to  o-i  per  cent." 

In  the  PusseUawa  district  the  soil  and  climate  appear  to 
resemble  those  in  sections  of  the  Peradeniya  and  Matale  districts, 
and  although  part  of  the  district  is  considered  to  be  too  high  for 
Hevea  rubber,  there  were  in  August,  1910,  about  2,700  acres  of 
this  product  planted  alone  or  with  tea. 

Ratnapura  and   Ambagamuwa. 

The  Ratnapura  district,  differing  so  widely  from  the  fore- 
going in  having  such  a  heavy  rainfall  and  being  one  already 
extensively  cultivated  in  rubber,  is  here  synoptically  dealt  with. 
The  acreage  in  August,  1910,  in  rubber  alone  was  14,036  acres, 
with  tea  3,557  acres. 

Regarding  the  mechanical  composition, ' '  out  of  about  a  dozen 
soils  ly  to  20  per  cent,  of  the  soil  passes  a  90  mesh,  16  to  25  per 
cent,  a  60  mesh,  and  4  to  5  per  cent,  a  30  mesh,  and  sand  and 
small  stones  account  for  from  50  to  60  per  cent.  The  retentive 
power  for  moisture  varies  from  3  to  5.  The  chemical  composition 
shows  from  10  to  12  per  cent,  of  organic  matter,  o-i  to  0-2  per 
cent,  of  nitrogen,  o-o6  to  0-2  per  cent,  of  lime,  0-07  to  0-15  per 
cent,  of  magnesia,  0-04  to  o-i  of  potash,  and  from  0-03  to  o-8 
per  cent:  of  phosphoric  acid. ' '  Hevea  rubber  has  been  extensively 
planted   in   this   and   the   surrounding   districts. 

In  the  Upper  Ambagamuwa  district,  where  the  rainfall  is  very 
heavy,  Hevea  rubber  trees  are  being  tapped  and  planting  opera- 
tions continued,  though  the  elevation  in  such  a  wet  district  is 
thought  by  many  to  be  near  the  maximum.     About  3,000  acres 


158  PARA    RUBBER 

were  planted  by  August,  1910,  and  some  of  the  plants  now  show 
satisfactory  growth. 

KUEUNEGALA    DISTRICT. 

The  rainfall  of  75  to  100  inches  is  evidently  suitable,  and  a 
general  glance  at  the  average  composition  of  the  soils  would  not 
be  out  of  place  here.  The  soils  vary  greatly,  as  can  be  seen  from 
the  following  figures  : — 

Mechanical  Composition. 


Per  cent. 

Fine  soil  passing  90  mesh  . . 

17  to  35 

Fine  soil  passing  60  mesh  .  . 

20  to  35 

Medium  soil  passing  30  mesh 

5  to     9 

Chemical  Composition. 

Per  cent. 

Coarse  sand  and  small  stones 

20  to  60 

Moisture        

3.to  7 

Humus  and  combined  water 

4  to  8 

Lime  . . 

o'l  to  0'35 

Magnesia 

o'l  to  o'45 

Potash           

D-o8  to  o-i8 

Phosphoric  acid 

0'02t0  0-04 

Nitrogen 

o'o8  toon 

In  August,  1910,  there  were  over  8,700  acres  of  rubber  alone 
and  with  intercrops  planted  in  this  district. 

Passara  District. 

In  the  Passara  district  there  were  in  August,  1910,  some 
9,200  acres  of  rubber  alone  and  interplanted.  The  results  from 
the  older  trees  being  tapped  at  all  elevations  up  to  nearly  3,000 
feet  are  satisfactory.  In  the  Uva  Province  the  climatic  conditions 
are  said  to  be  such  as  to  allow  of  the  cultivation  of  Hevea  rubber 
up  to  an  elevation  of  2,900. 

' '  Very  few  soils  have  been  analysed  from  the  Province  of  Uva, 
but  from  those  obtained  from  Passara  the  following  information 
has  been  compiled.  Usually  from  17  to  30  per  cent,  passes  the 
90  mesh,  20  to  30  per  cent,  the  60  mesh,  7  to  8  per  cent,  the  30 
mesh,  and  sand  and  small  stones  form  from  40  to  43  per  cent.  The 
retentive  power  for  moisture  is  about  2J.  The  chemical  analyses 
show  the  presence  of  from  7  to  11  per  cent,  of  organic  matter,  o-i 
to  0-15  per  cent,  of  nitrogen,  o-o6  to  o-i  per  cent,  of  lime,  0-07  to 
0-13  per  cent,  of  magnesia,  0-05  to  o-o8  per  cent,  of  potash,  and 
from  0-03  to  0-04  per  cent,  of  phosphoric  acid." 

Soils  in  South  India. 
There  are  extensive  areas  of  alluvial  soil,  lying  within  regions 
of  abundant  rainfall,  stretched  along  the  West  Coast  through 
Cochin,  Malabar,  etc.,  which  are  quite  suitable  for  Hevea.  Windle 
considers  that  Cochin  is  an  ideal  land  for  Hevea.  The  soil  is 
a  deep,  well-drained  loam,and  the  country  flat  or  gently  undulating. 
Elsewhere,  in  possible  rubber-growing  districts,  ferruginous  soils 


PARA     RUBBER 


159 


of  various  characters  are  met  with  ;  even  laterite  occurs  in  some 
areas.  The  analyses  below  are  each  the  average  of  a  number 
of  samples,  all  of  coffee  soils  in  various  parts  of  South  India ; — 

Yarcand,       Munjerabad, 
Shevaroy  Mysore. 

Coorg.  Hills.         (By  Voelcker) 

(ByMassey)  (By  Leather.)      Laterite. 
%  %  % 


Moisture  . . 

6-334 

? 

? 

Humus  and  combined 

water 

4-201 

12-87 

11-36 

Oxides  of  iron 

4-186 

10-10 

9-63 

Alumina  . . 

6158 

18-64 

i5'24 

Lime 

0-920 

00-36 

00-28 

Magnesia 

0-279 

00-53 

00-30 

Potash      . . 

0-655 

00-20 

00-15 

Soda 

0-355 

00-05 

00- 1 1 

Phosphoric  acid 

0-622 

00-12 

00-13 

Sulphuric  acid 

0-178 

00-01 

00-03 

Chlorine  . . 

0-056 

p 

00-003 

Silica  and  insoluble 

matter 

70-419 

5678 

6i-37 

Nitrogen 

0-792 

00-123 

00-157 

Hevea  Soils  in  the  Federated  Malay  States. 

I  was  indebted  to  the  late  J.  B.  Carruthers  for  much  informa- 
tion regarding  the  land  and  soil  in  various  parts  of  the  Federated 
Malay  States.  The  rocks  from  which  most  of  the  non-alluvial 
soils  are  formed  are  limestones,  sandstones,  laterites,  and  granites, 
the  disintegration  products  of  red  laterite  being  considered  good. 
The  low-lying  land  at  the  foot  of  the  mountain  range  is  composed 
of  a  deep  alluvial  deposit  ;  the  subsoil  in  such  areas  is  said  to  be 
far  below  the  water-level,  and  for  purposes  of  cultivation  may 
therefore  be  neglected.  The  majority  of  the  alluvial  land  planted 
in  Hevea  rubber  is,  if  anything,  too  well  supplied  with  water, 
the  latter  being  within  3  to  4  feet  from  the  surface  all  the  year 
round.  The  water-level  all  over  the  plains  on  the  west  of  the 
mountain  range  is,  according  to  Carruthers,  very  near  the  surface — 
often  as  near  as  16  to  18  inches. 

On  the  estates  I  visited  in  the  Klang  district,  the  soil  was 
composed  of  a  rich  clayey  loam  with  plenty  of  humus  in  the  first 
twelve  inches,  and  a  stiffer  bluish  clay  below.  It  is  often  so  soft 
that  one  can  push  a  walking  stick  out  of  sight  with  a  little  exertion. 
There  is  hardly  a  stone  to  be  seen  on  many  estates,  and 
the  land  is  mainly  flat.  The  water-level  on  many  estates  was 
observed  to  be  from  one  to  two  feet  below  the  surface.  It  is  the 
custom  to  drain  the  land  prior  to  felling,  in  order  that  the  soil  may 
have  a  chance  to  dry  and  sink  before  planting  operations  are 
commenced. 

Bamber  states  that  some  samples  of  Malay  soils  pass  almost 
entirely  through  a  sieve  of  8,100  meshes  to  the  inch.  The  organic 
matter  frequently  exceeds  30  per  cent.,  and  the  nitrogen  is  some- 
times as  high  as  0-9  per  cent.     These  high  percentages  are  not. 


i6o 


PARA     RUBBER 


however,  obtainable  over  all  estates  in  the  Federated  Malay  States. 
Many  of  the  Ceylon  soils  are  quite  as  good  as,  and  occasionally 
superior  from  a  chemical  standpoint  to,  those  in  the  Federated 
Malay  States,  but  in  only  a  few  low-country  soils  in  Ceylon  does 
the  organic  matter  reach  20  per  cent.  In  relation  to  Ceylon 
soils  the  mineral  contents  of  the  Federated  Malay  States  soils 
are  very  often  inferior,  the  chief  deficiency  being  potash  rather 
than  phosphoric  acid. 

In  many  parts  of  the  Malay  Peninsula,  usually  near  tidal 
rivers,  a  peat  formation  occurs.  It  is  composed  of  dead  timber, 
roots,  and  decayed  leaves,  sometimes  to  a  depth  of  twenty  feet, 
clay,  stones,  etc.,  being  absent.  The  water  of  these  "soils" 
contains  an  excess  of  humic  acid.  The  deaths  or  vacancies  are 
very  large,  often  nearly  100  per  cent.  One  or  two  well-known 
plantations  have  been  tried  on  such  land  and  so  far  have  been 
failures. 

Selangor    Soils. 

As  so  many  notable  Hevea  plantations  have  been  established 
in  Selangor  the  following  analyses,  by  R.  J.  Eaton,  are  here 
given  : — 

Ix)ss  of  moisture  at  100°  C. 
Humus  and  combined  water 
Oxide  of  iron 
Alumina 
Manganese 
Lime 
Magnesia 
Soda 

Potash     . . 
Phosphoric  acid  , 
,    Sulphuric  acid 
Insoluble  sand  and  silicates 


No.  I. 

No.  2. 

6-490 

11-260 

5-290 

6430 

4-900 

1-400 

5-790 

6-658 

0-050 

0-065 

0-065 

0-065 

0-130 

0-115 

0-160 

0-160 

o-io6 

0-106 

o-io8 

0-112 

0-026 

0-004 

76-885 

73-625 

Typical  Soils  of  Malay  States. 

Bamber,  in  a  report  published  by  the  late  J.  B.  Carruthers, 
stated  that  ' '  the  soils  of  Malaya  may  be  roughly  divided  into  two 
distinct  kinds  : 

"(a)  The  flat  alluvial  clays  or  muds  on  the  banks  of  rivers 
and  near  the  sea  coast. 

' '  (b)     The  undulating  low  soils  a  few  miles  inland,  where  they  ■ 
vary  from  free  sandy  loams  to  heavy  clays. 

The  alluvial  clays  or  muds  are  in  an  exceedingly  fine  state  of 
division,  about  96  per  cent,  passing  through  a  mesh  of  8,100  per 
square  inch,  and  the  balance  through  a  mesh  of  3,600  per  square 
inch.  Although  having  the  appearance  of  fine  clays  there  is  very 
little  alumina  present,  the  bulk  of  the  soil  being  composed  of  very 
finely-divided  sand  and  insoluble  silicates.  When  wet  they  are 
compact  and  greasy,  but  on  drying  they  break  up  into  compara- 
tively free  loams,  through  which  roots  can  permeate  freely,  so  that, 
unless  liable  to  flooding  with  salt  water,  they  are  all  well  suited  for 
the  growth  of  Hevea,  coconuts,  and  Liberian  coffee.     The  amount 


PARA     RUBBER  i6i 

of  organic  matter  in  these  soils  varies  considerably — from  8  to 
35  per  cent.,  or  even  more  if  the  surface  layer  is  at  all  peaty. 
They  are  generally  very  rich  in  nitrogen,  containing  from  0-4  to 
0-9  per  cent,  on  the  air-dried  soil ;  a  soil  with  0-2  per  cent,  being 
considered  rich  in  other  countries. 

With  regard  to  the  mineral  matter,  which  forms  the  ash  of  the 
plants,  they  are  not  so  rich,  although  the  exceedingly  fine  state 
of  division  of  the  soils  renders  a  high  proportion  less  necessary. 
They  are  more  or  less  deficient  in  lime,  which  accounts  for  the 
markedly  acid  character  of  the  soils  when  first  opened ;  the  acidity 
is  neutralized  to  some  extent  by  ash  from  the  burnt  forest,  but  it 
also  gradually  diminishes  as  the  drainage  water  is  removed  to  a 
lower  level  and  the  soil  becomes  aerated.  Magnesia  is  present  in 
ample  quantity  in  most  cases.  Potash,  one  of  the  chief  mineral 
constituents  required  for  plant  growth,  is  frequently  deficient, 
though  a  few  of  the  river  deposits  are  rich  in  this  constituent,  and 
the  subsoil  is  usually  richer  than  the  surface  soil  especially  if  of  a 
clayey  nature.  The  proportion  of  phosphoric  acid  is  also  variable, 
ranging  from  0-012  to  0-13,  the  average  being  about  0-076  per  cent. 
on  the  air-dried  soil.  All  this  class  of  soil  requires  very  efficient 
drainage  as  it  has  often  been  more  or  less  under  water  for  years,  so 
that  air  has  been  excluded,  resulting  in  a  rather  high  proportion  of 
the  lower  oxide  of  iron,  which  in  excess  is  poisonous  to  many 
cultivated  plants.  The  vigorous  growth  of  rubber  on  this  class  of 
soil  after  drainage  is  unequalled  elsewhere  during  the  first  years, 
of  growth. 

"They  are  richer  in  nitrogen  than  the  proportion  of  organic, 
matter  would  indicate,  but  are  usually  a  little  deficient  in  total 
potash  and  to  some  extent  in  phosphoric  acid. 

"Their  free  character  and  suitability  for  root  growth  makes 
the  proportion  of  the  set  constituents  ample  for  present  require- 
ments, and  it  is  evident  from  the  growth  of  Hevea  on  these  soils 
that  there  is  no  deficiency  in  any  respect." 

The  following  analyses  (Bamber)  show  the  composition  of 
alluvial  and  sandy  loams  in  Malay  : — 

Chemical  and  Physical  Analyses  of  Federated  Malay  States  Soils. 

Alluvial  Clays.  Sandy  Loams. 

Mechanical  Composition  : — 

%  %  %  %  %  % 

Fine  soil  passing  90 

mesh  .  .         9600        9550       6800        3000        3600        2600 

Fine  soil  passing    60 

mesh  . .  400  450        3200        3400        3800        30'oo 

Medium  soil  passing 

30  mesh  . .  —  —  —  26'oo  8'oo        22'oo 

Coarse     sand     and 

small  stones     . .  —  —  —  1000        1800        2200 


lOO'OO    lOO'OO    lOO'OO    I00"00    lOO'OO    lOO'OO 


l62 


PARA    RUBBER 


Alluvial  Clays. 

Sandy 

Loams. 

Chemical  Composition 

: — 

Moisture 

6'920 

5'56o 

5-000 

1-400 

4-000 

2-200 

Humus    and    com- 

bined water     .  . 

24'o8o 

16-640 

8-000 

3000 

9-600 

5-600 

Oxide  of  iron   and 

manganese 

II20 

I  200 

3-000 

0-300 

8-240 

0-700 

Oxide  of  alumina  .  . 

2-971 

3-019 

2-520 

1-165 

4-183 

2-516 

Lime 

0-284 

0-200 

0-160 

0-140 

o-i6o 

0-160 

Magnesia 

0252 

0-381 

0-230 

0-130 

o-ioo 

0-130 

Potash 

0-I3I 

0-169 

0-014 

0-014 

0-053 

0-030 

Phosphoric  acid     .  . 

0025 

001 2 

0076 

0051 

0-064 

0064 

Sand  and  siUcates .  . 

64-200 

72-800 

8 1  000 

93-800 

73-600 

88-600 

Chlorine 

0017 

0-019 

1 00  000 

— 

— 

— 

loo-ooo 

lOOOOO 

lOOOOO 

lOOOOO 

lOOOOO 

Containing  nitrogen 

0-667 

o'425 

0-403 

0-492 

0-386 

0-403 

Equal  to  ammonia 

0-810 

0-516 

0-489 

0-59S 

0-469 

0-489 

Lower  oxide  of  iron 

Much 

Fair 

Good 

Good 

Good 

Good 

Acidity 

— 

— 

Marked 

Marked 

Marked 

Marked 

Soils  in 

Java. 

The  fertile  soil  of  Java  is  well  known.  Its  richness  is  due 
mainly  to  its  volcanic  origin.  The  ranges  of  volcanic  hills  are 
very  conspicuous  in  the  Kederi  and  Pasoeroean  residencies,  where 
notable  Hevea  estates  now  exist.  Some  of  the  old  volcanoes  are 
rugged  and  steep,  whilst  others  have  a  gentle  slope  many  miles 
in  length.  They  form  the  interesting  feature  of  the  country  in 
most  of  the  districts.  There  are  several  well-known  companies 
that  Ijave  their  estates  along  the  sides  of  volcanic  mountains. 
The  crops  are  good,  and  dividends  high.  In  contrast  with  these, 
in  situation,  are  the  estates  in  the  Langen  district,  where  rubber 
is  planted  on  land  as  fiat  as  a  billiard  table.  Most  of  the  rubber 
estates  are  planted  on  gently  undulating  or  fiat  land.  The  water- 
level  is  usually  many  yards  below  the  surface,  in  this  respect 
differing  from  Malaya.  I  have  seen  only  two  estates  which  for 
their  steep  slopes  approach  much  of  the  rubber  land  in  Ceylon. 
The  Java  rubber  estates  I  have  seen  are  notable  for  the  absence  of 
stony,  rocky  slopes,  such  as  one  meets  with  in  Ceylon,  and  for 
the  comparative  scarcity  of  swamps  so  abundant  in  Malay. 

The  soil  is,  almost  without  exception,  of  first-class  quality. 
It  usually  consists  of  a  dark-red  finely-divided  loam,  sometimes 
light  and  sandy,  at  other  times  a  trifle  clayey.  It  is  a  volcanic 
soil  on  which  luxuriant  vegetation  has  been  grown  for  many  years. 
Physically  it  is  often  perfect,  and  chemically  nearly  so. 

Analyses  are  given  below  of  soils  in  rubber-growing  districts 
in  East  and  West  Java.  The  first  three,  by  Szymanki  and 
Schohren,  are  each  the  average  of  five  samples  from  the  same 
area.  The  fourth,  by  Kramer,  is  the  average  of  three  soils  of 
slightly  different  characters.     All  are  clay  soils. 


PARA     RUBBER 


163 


Padhipaten 

Kemantren 

Kalibagor 

Pasoeroean 

Poppoh 

(Cheribon) 
0/ 

(Pekalongan)   (Banjoemas) 

0/                      0/ 

0/ 

(Soerabaya) 
0/ 

Humus  & 

/o 

/o 

/o 

/o 

70 

combined 

water 

7'342 

8-300 

9-760 

? 

8-90 

Lime 

.     o-6o8 

0-854 

0-664 

1-22 

4-00 

Magnesia . 

0-073 

0-067 

0059 

0-22 

1-32 

Potash     . 

0-058 

0-048 

0-069 

0-13 

0-07 

Phosphoric 

acid 

0-037 

0086 

0-050 

0-05 

003 

Nitrogen  . 

0-050 

0059 

0133 

0-08 

? 

Soils  in  Sumatra. 

The  soils  are  somewhat  similar  to  those  in  Java,  being  light, 
fertile,  and  mainly  of  volcanic  origin.  Busse  (Tropenpflanzer, 
Feb.,  1906),  remarks  that  in  Sumatra  rubber  is  cultivated  upon 
alluvial  loams  of  a  sandy  nature  as  well  as  upon  volcanic  soils, 
which  are  very  sandy,  reddish-yellow  loams.  The  growth  is  good 
on  the  higher  volcanic  soils  owing  to  the  absence  of  ground-water 
and  to  the  greater  rainfall.'  In  the  case  of  the  alluvial  soils  growth 
is  healthy  at  first,  but  is  less  rapid  later,  unless  deep  drains  are 
cut.  The  following  analyses,  by  Schidrowitz,  of  a  soil  in  the 
Siantar  district  (Eastern  Sumatra  Rubber  Company),  on  which 
secondary  and  primary  forest  were  flourishing,  will  give  some 
idea  of  the  richness  in  certain  constituents,  and  of  the  good 
mechanical  condition  of  the  soil  in  this  area.  The  poverty  of 
one  soil  in  phosphoric  acid  and  of  both  in  lime  will  be  noted. 

Mechanical  Analyses. 


I. 

n. 

Passing  90"  mesh 

57 

4' I 

60"      ,,                ... 

5-7 

4'3 

„       30"      ..                ... 

265 

30-1 

Coarse  sand  and  gravel  . . 

62-1 

61-5 

Chemical  Analyses. 

I. 

II. 

Moisture 

25-03 

17-01 

Humus  and  combined  water 

5-12 

4'55 

Iron 

Much 

Much 

Carbonates  . . 

Nil 

Nil 

Lime 

Trace 

Trace 

Potash         

0-260 

0-210 

Phosphoric  acid 

0-072 

0-007 

Nitrogen 

0-270 

0-340 

Nitrogen  equal  to  ammonia 

0-330 

0-410 

Citric  soluble  potash 

o-oi6 

0-014 

Citric  soluble  phosphoric  acid 

o-oio 

0-003 

Acidity 

Faint 

Faint 

To  these  may  be  added  the  averages  of  certain  analyses, 
made  by  Hissink  (Journ.  Landw.,  1905)  of  dark,  humus-rich 
tobacco  soils  from  Deli  : — 


Padang 

Boelan. 

0/ 

Soengei 

Mentjerim. 

0/ 

C 

■Jo/ 

Namoe 
Oekoer. 

0/ 

Lime 
Potash 

Phosphoric  acid 
Nitrogen 

/o 

0-09 
0-05 
0-52 
0-63 

/o 
o"35 
o-io 

0-53 
0-49 

/o 

0-36 
0-05 
0-40 

0-51 

/o 

0-42 

o-ii 

o'43 
0-84 

164 


PARA     RUBBER 


Soils  in   British  New  Guinea. 

It  is  reported  by  Guthrie  and  Symmonds  (Agric.  Gazette, 
New  South  Wales,  April,  1908),  who  examined  twelve  typical 
soils,  that,  speaking  generally,  they  were  rich,  fertile  soils  of  a 
loamy  nature,  friable  and  fairly  easy  to  work.  The  capacity  for 
retaining  water  was  high  in  all  cases,  and  the  humus  content  was 
satisfactory.  Of  the  following  soils,  the  two  first  were  from  the 
East  Coast,  the  area  in  which  rain  is  most  abundant ;  the  third  was 
from  the  hills  above  Port  Moresby,  and  in  a  district  where  there 
are  coffee  plantations. 


Buna  Bay. 

Milne  Bay. 

Sogeri. 

Grey  loamy 

Dark  brown 

Brown 

sand. 

0/ 

sandy  loams. 

0/ 

loam. 

0/ 
/o 

Mechanical  Composition. 

/o 

/o 

Stones 

— 

1-54 

4'54 

Gravel      . . 

— 

3'I4 

1-14 

Coarse  sand 

— 

3-87 

I  06 

Sand 

82-70 

68-50 

41-40 

Fine  sand 

2-34 

3-20 

3-80 

Silt 

170 

2-20 

2-22 

Fine  silt   .  . 

1-70 

I -60 

6-04 

Clay 

10-46 

13-40 

29-37 

Chemical  Composition. 

Moisture  . . 

i-io 

^'55 

10-43 

Humus  &  combined  water           5-02 

5'90 

13-67 

Soluble  in  hot  hydrochloric  acid 

{Sp.  gr.  I -I)  .•— 

Lime 

0-722 

I '593 

0-048 

Potash     . . 

0069 

0-252 

0023 

Phosphoric  acid 

0205 

0-999 

0-231 

Nitrogen 

0-126 

0-182 

0-182 

Reaction 

Neutral 

Faintly 

Very  strongly 

acid 

acid. 

Soils  in  Hawaii. 

In  view  of  the  experiments  being  made  to  cultivate  Hevea 
in  this  part  of  the  world,  the  following  analyses  (Thompson, 
Hawaiian  Agr.  Exp.  Str.,  1908),  may  be  of  interest : — 


Brown 

Dark  red 

Dark  brown 

loam 

loam 

loam 

0/ 

/o 

0/ 

% 

Moisture          ..          ..          ..          14-141 

3-763 

7-536 

Humus  and  combined  water                — 

15-864 

13-660 

Nitrogen 

0-505 

0-295 

0-226 

Phosphoric  acid 

0-185 

0-127 

0-127 

Potash 

0-178 

0-547 

0-148 

Lime     . . 

0-590 

0-940 

1-720 

Magnesia 

1-622 

0-450 

I  "564 

Manganese  oxide 

0-115 

0-400 

0-130 

Acidity 

acid 

neutral 

? 

Soils   in   the   West   Indies   and   South  America. 
According  to  Hart,  the  following  are  types  of  good  cacao 
soils    as    determined    in    the    Government    Laboratory,    British 
Guiana  ;    they  should  be  well  suited  for  Hevea  rubber  : — 


PARA     RUBBER 


165 


Demerara. 

Grenada. 

Trinidad. 

Surinam 

Humus  and  combined  w 

ater 

.     9-031 

10-442 

3-768 

i5'452 

Phosphoric  anhydride 

o'oSy 

0-184 

0-084 

0-I39 

Sulphuric  anhydride 

o'oiS 

traces 

traces 

0-047 

Chlo'Hne 

traces 

nil 

nil 

traces 

Iron  peroxide 

•      4783 

9'485 

3-910 

5-952 

Alumina  . . 

■      9'2I7 

10-024 

2-038 

16-076 

Manganese  oxide 

■      0'347 

o'3i3 

0-127 

nil 

Calcium  oxide 

■      o'596 

2-379 

o'356 

0-495 

Calcium  carbonate 

0032 

0-026 

nil 

nil 

Magnesium  oxide 

0-404 

3'367 

0'495 

1-071 

Potassium  oxide . . 

0291 

o"343 

0-118 

0-072 

Sodium  oxide 

.     o-2o8 

o'574 

0-278 

0-258 

Insoluble  silica  and  silic 

ites 

•  74-986 

62-863 

88-826 

59-438 

lOO'OOO 

loo-ooo 

loo-ooo 

loo'ooo 

Containing  nitrogen 

0-262 

0-271 

o-ioo 

0-366 

Water     retained     by 

air-drie 

d 

soil    . . 

■     6-5 

12-4 

1-8 

ri-00 

In  Jamaica,  Hevea  has  been  reported  a  failure  on  account  of 
the  absence  of  a  stiff,  clay  soil.  But  Ridley  (Str.  Bull.,  Feb., 
1910),  points  out  that  Hevea  grows  on  rocky  laterite  hills  as  well, 
if  not  better,  than  on  stiff  clay  soils.. 

Soils  in  British  Guiana. 

In  British  Guiana,  Hevea  brasiliensis  does  not  appear  to  have 
grown  very  satisfactorily  in  the  heavy  clay  lands  at  the  Botanic 
Gardens.  It  is  reported  to  be  growing  well  on  the  clayey  loams 
at  Onderneeming,  and  also  on  the  pegassy-clay  lands  at  the 
Issorora  Station,  but  not  so  rapidly  on  the  lateritic  hiU-slopes. 
Several  young  plants  on  clay  soils  at  Christianburg  are  promising, 
although  older  trees  have  not  grown  very  satisfactorily. 

Manuring  to  Increase  the  Yield  of  Latex. 

If  latex  is  mainly  an  excretory  or  useless  product  it  may  appear 
doubtful  as  to  whether  manuring  will  have  a  beneficial  effect  on  the 
rubber-producing  capacity  of  the  tree.  This  is  an  interesting 
point,  and  is  well  worth  considering. 

The  latex  is  obtained  from  cortical  tissues.  These  areas 
contain,  besides  the  latex  tubes,  series  of  cells  which  store  up  food, 
and  others  directly  associated  with  conducting  the  materials 
elaborated  in  the  leaves  from  above  downwards  to  various  parts  of 
the  plant.  These  tissues  are  removed  in  the  course  of  tapping 
operations,  and  their  renewal  entirely  depends  upon  the  activity  of 
the  cambium.  The  cambium  produces  new  wood  internally  and 
cortical  tissues  externally  ;  generally  the  cambium  produces  these 
two  series  of  tissue  in  a  definite  order,  and  a  large  production  of 
woody  material  is  accompanied  by  a  proportionate  amount  of 
cortical  tissues.  As  the  wood  is  marked  off  into  annual  zones  it  is 
therefore  possible  to  compare  the  rate  of  growth  of  trees  in  diff- 
erent countries  by  examination  of  transverse  sections  of  the 
trees,  and  indirectly  to  form  some  idea  of  the  time  required  in  the 


i66  PARA    RUBBER 

development  of  the  narrow  band  of  cortical  tissues  containing 
the  laticifers. 

The  latex  tubes  form  part  of  the  cortical  tissues,  and  an  in- 
creased leaf  activity  appreciably  affects  the  elements  in  this  region. 
The  more  abundant  the  foliage,  the  more  rapidly  will  the  food 
material  be  built  up  and  the  more  vigorous  will  the  cambium 
become.  From  these  and  other  considerations  it  may  be  con- 
cluded that  if  manuring  is  carried  out,  so  that  the  growth  of  the 
leaves  and  woody  material  is  appreciably  increased,  the  cortical 
tissue  will  be  proportionately  increased  in  quantity,  and  there 
will  be  a  larger  number  of  cells  available  for  transformation  into 
laticiferous  tubes.  Any  manure  which  affects  the  growth  of  the 
leaves  or  the  wood  must  have  a  corresponding  effect  on  the  cortical 
tissues.  The  main  object  in  manuring  Hevea  trees  should  be  to 
increase  the  number  of  cortical  cells  as  rapidly  as  possible  ;  this 
increase  is  dependent  upon  the  activity  of  the  cambium,  though 
the  subsequent  condition  of  the  newly-formed  elements  is  closely 
associated  with  the  abundance  and  activity  of  the  leaves.  It 
may  appear  absurd  to  advocate  manuring  with  a  view  to  in- 
creasing what  is  commonly  regarded  as  mainly  a  waste  product,  but 
it  cannot  be  gainsaid  that  abundance  of  cortical  tissue  provides 
more  cells  for  perforation  and  disintegration,  stages  involved  in 
the  formation  of  the  latex  tubes  of  Hevea  brasiliensis. 

Experiments  on  Manihot  in  Hawaii. 

In  the  Hawaiian  Islands,  at  Keanae,  experiments  were 
carried  out  (Hawaiian  Agric.  Exper.  Station,  Bull.  19,  1910),  by 
Wilcox,  to  determine  the  effect  upon  the  yield  of  manuring  with 
nitrate  of  soda,  but  upon  Ceara  trees.  They  were  divided  into 
three  groups  of  three  trees  each.  The  group  receiving  one  half 
pound  per  tree  gave  2-3  ozs.  of  dry  rubber  ;  that  receiving  one- 
quarter  pound  per  tree  gave  1-3  ozs.  ;  that  receiving  none  gave  i'2 
ozs.  The  effect  of  the  manure  was  manifested  in  48  hours,  the 
weather  being  rainy  during  the  experiment.  In  another  ex- 
periment, at  Tantalus,  the  yield  of  rubber  was  doubled  by  the 
application  of  one  half-pound  per  tree.  A  further  test  was  made  on 
trees  at  the  station.  One  group  of  five  trees  gave  0-9  ozs.  in  the 
three  days  before  the  nitrate  was  applied,  and  1-3  ozs.  in  the 
three  days  following.  Another  group  of  five  trees  in  the  same 
times  gave  0-9  ozs.  before  and  i'2  ozs.  after.  These  results  may 
indicate  the  possible  effect  of  manuring  on  the  latex  of  Hevea 
brasiliensis. 

The  analyses  of  various  parts  of  Hevea  brasiliensis  given 
elsewhere  should  be  carefully  considered  when  mixtures  of  artificial 
manures  for  rubber  are  being  compounded. 

Forest   Vegetation   and    Soil   Improvements. 

It  must  be  remembered  that  Hevea  rubber  trees  form  a  forest 
vegetation,  and  that  they  will  grow  well  in  relatively  inferior  soils 
providing  there  is  a  fair  balance  of  plant  food  and  that  the  climatic 


PARA     RUBBER  167 

conditions  are  favourable.  In  fact,  the  outstanding  feature  of 
Hevea  brasiliensis  is  that  it  can  grow  on  soils  and  in  climates  which 
exhibit  great  variability.  The  soil  under  forest  vegetation  im- 
proves in  mechanical  and  chemical  composition  with  age,  owing 
to  the  protection  which  the  trees  afford  to  the  soil,  to  the  action  of 
the  roots,  and  the  accumulation  of  leaf-mould.  The  annual  fall 
of  leaf  from  Hevea  rubber  trees  ultimately  effects  an  improvement 
in  the  soil  in  which  the  trees  are  being  grown.  This  is  borne  out  by 
the  analyses  of  the  soils  at  Henaratgoda,  the  results  proving  that 
the  organic  matter,  potash,  and  nitrogen  are  greater  in  the  soil 
which  has  been  under  rubber  for  29  years  than  that  maintained 
under  pasture  ;  the  lime  and  magnesia  have  decreased  under  the 
old  rubber,  while  the  phosphoric  acid  is  the  same  under  both 
conditions. 

Food    in    Hevea    Leaves. 

The  manurial  value  of  the  leaves  from  Hevea  rubber  trees 
cannot  be  doubted  when  it  is  remernbered  that  the  material,  dried 
at  ioo°C.,  contains  1-72  per  cent,  of  potash,  3-44  per  cent,  of  nitro- 
gen, 0-6  per  cent,  of  phosphoric  acid,  and  0-51  per  cent,  of  lime. 
If  this  material  is  regularly  forked  in  either  alone  or  with  lime 
or  artificial  manures,  excellent  results  will  be  obtained.  The 
artificial  manure  required  will  largely  depend  upon  the  physical 
and  chemical  properties  of  the  soil,  but  the  figures  showing  the 
composition  of  various  parts  of  the  Hevea  rubber  plant  will 
indicate,  in  a  general  way,  the  ingredients  required.  Potash  and 
nitrogen  are  very  abundant  in  the  fresh  and  fallen  leaves  and  lime 
is  abundant  in  the  woody  structures.  Lan  [Notes  sur  I'Hevea 
brasiliensis,  191 1),  showed  that  yellow  leaves  when  about  to  fall 
from  the  tree  possessed,  when  freshly  gathered,  0-49  per  cent,  of 
nitrogen  or  1-14  per  cent,  in  the  material  diied  at  ioo°C.  The 
fresh  yellow  leaves  also  contain  0-12  per  cent,  of  phosphoric  acid, 
and  0-20  per  cent,  of  potash. 

Application  of  Readily  Soluble  Manures. 

The  method  to  be  adopted  in  manuring  this  plant  is  deter- 
mined by  the  age  of  the  trees  and  the  kind  of  manure  used. 

Where  very  soluble  manures  such  as  sodium  and  potassium 
nitrate,  ammonium  sulphate,  potassium  chloride  or  sulphate,  and 
similar  compounds  are  used,  they  should  be  mixed  with  dry  earth 
and  broadcasted  over  the  area  where  the  young  rootlets  are  actively 
growing.  If  such  manures  are  applied  to  soil  areas  not  possessing 
rootlets,  the  greater  part  will  probably  be  carried  away  during  the 
first  few  rainy  days.  After  the  manures  have  been  applied,  the 
land  should  be  forked  to  a  depth  of  four  to  six  inches,  but  care 
should  be  taken  not  to  destroy  many  of  the  rootlets.  Decaying 
rootlets  may  encourage  ants  and  fungi.  The  young  rootlets  which 
absorb  the  manure  are  not  near  the  stem  of  the  tree,  but  usually 
some  distance  from  it ;  hence  the  necessity  to  scatter  the  manure 
some  distance  from  the  trunk.  Cowie  recommends  (I.R.J. ,  April, 
1909)    that    artificial   manures   be  sprinkled  round  the  tree  at  a 


i68  PARA    RUBBER 

distance  of  from  i  to  i|  feet  from  the  stem  for  each  year  of  the 
plant's  growth  and  then  very  hghtly  forked  into  the  soil.  In  order 
to  prevent  the  manure  from  being  washed  away  by  the  rain,  how- 
ever, a  shallow  trench  may  be  cut  round  the  tree,  the  manure 
forked  therein  and  the  surface  soil  then  replaced. 

Application  of  Bulky  Manures. 
Where  cattle  manure,  green  manure,  leaf-mould,  or  bulky 
artificial  manures  are  used  on  rubber  estates,  a  shghtly  different 
method  can  be  adopted.  The  object  in  such  manuring  is  not  only 
to  supply  at  a  very  short  notice  ingredients  required  for  the  rapid 
growth  of  parts  of  the  plant,  but  to  lead  to  the  development  of  a 
quicker-growing,  larger,  and  stronger  root-system.  This  result  can 
be  obtained  if  the  organic  manure  is  mixed  with  the  soil  around 
the  trees  at  a  definite  distance  according  to  the  age  of  the  tree. 
The  rootlets  of  the  Hevea  rubber  tree  grow  at  a  fairly  rapid  rate  in 
good  free  soil,  and  can  be  easily  observed.  The  manure  should  be 
applied  at  a  distance  just  within  reach  of  the  last-formed  rootlets. 
Around  each  newly-planted  tree  a  shallow  trench  can  be  dug, 
about  12  inches  wide  and  gradually  increasing  in  depth  from  the 
tree  outwards  to  a  maximum  depth  of  six  to  ten  inches.  The 
manure  can  then  be  mixed  with  part  of  the  soil,  returned  to  the 
trench,  and  subsequently  covered  with  the  balance  of  soil  available. 
The  distance  of  the  trench  from  the  tree  might  be  approximately 
2  feet  or  more  for  two-year-old  trees,  3  feet  or  more  for  three-year- 
old  trees,  an  allowance  of  about  one  to  two  feet  per  year  being 
made  in  each  subsequent  year  until  the  trees  are  6  to  8  years  old, 
when  the  lateral  roots  will  almost  certainly  have  met.  By  such  a 
system  of  manuring  the  rubber  plants  will  be  able  to  obtain  a 
supply  of  food  at  a  very  early  stage,  and  the  development  of  the 
rootlets  from  within  outwards  be  considerably  accelerated.  Once 
the  rootlets  of  adjacent  trees  have  met,  the  manure  should  be 
either  buried  in  shallow  trenches  between  the  trees  or  broadcasted 
and  the  ground  forked  to  a  depth  of  4  to  6  inches  or  left  undis- 
turbed. 

Manuring    Young    Plants. 

A  convenient  time  for  manuring  young  plants  is  when 
planting  out  has  been  completed,  for  the  young  plants  are  helped 
at  a  crucial  period,  and  further,  the  manure  is  brought  within  the 
immediate  reach  of  the  rootlets.  In  Cochin  China,  on  a  poor,  sandy 
soil,  seven  ounces  of  ground-nut  oilcake  has  been  put  into  each 
hole  when  planting.  It  is  not,  however,  usual  to  go  to  con- 
siderable expense  in  manuring  young  plants,  though  this  work 
might  conceivably  be  sometimes  carried  on  with  advantage. 

Artificial  and  Green  Manures. 

The  use  of  both  kinds  of  manures,  on  the  same  area,  is  often 
advisable.  It  is  sometimes  an  advantage  to  broadcast  readily 
soluble  manures  over  land  on  which  a  young  crop  of  herbaceous 
green  manures  is  coming  up  ;    this  leads  to  more  rapid  growth, 


PARA     RUBBER  169 

and  consequently  a  better  cover  and  more  effective  check  to  the 
growth  of  weeds.  When  the  green  crop  is  applied  to  the  land  the 
rubber  trees  would  benefit  from  the  original  application  of  soluble 
manures.  In  other  instances  large  quantities  of  concentrated 
artificial  manures  are  applied,  in  addition  to  lime  and  basic  slag, 
when  the  green  crop  is  forked  in  the  land  or  buried  in  trenches. 
A  mixture  composed  of  34  parts  of  potassium  chloride,  44  of 
precipitated  superphosphate,  and  22  of  finely-divided  bonemeal 
has  been  so  used. 

Results  of  Manuring  Experiments. 

As  previously  pointed  out  (I.R.J.,  July  29th,  1907),  I  have 
been  placed  in  possession  of  the  results  of  several  manurial  experi- 
ments, in  which  (a)  green  manure  and  lime,  (b)  cattle  manure  and 
lime,  (c)  cattle  manure,  lime,  and  artificial  manures,  and  (d)  arti- 
ficial manures  only,  have  been  used  on  Eastern  rubber  estates. 
The  results  clearly  show  that  manuring  may  bring  the  trees  to  a 
tappable  size  six  to  twelve  months  before  the  usual  time,  a  point 
which  must  appeal  to  all  interested  in  developmental  companies. 
The  requisite  quantities  of  the  various  essential  ingredients  vary 
with  the  age  of  the  trees  and  climatic  and  soil  conditions,  and  only 
a  continuation  of  the  experiments  on  a  large  scale  can  give  us 
accurate  information  on  this  point.  It  appears  to  have  been 
proved,  however,  that  potash  and  nitrogen  produce  the  most 
immediate  effect,  and  will  both  be  required.  Nitrogen,  if  applied 
in  excess  or  in  very  soluble-  forms,  appears  to  be  followed  by  a 
conspicuous  development  of  foliage  not  always  desirable,  and  some 
care  must  be  exercised  in  fixing  the  quantity  and  nature  of  arti- 
ficial nitrogenous  manures.  Potash,  as  might  have  been  antici- 
pated from  a  consideration  of  analyses  of  parts  of  the  plant,  is 
needed  in  large  quantities,  and  its  application  has  so  far  been 
attended  with  profitable  results. 

Manurial  Experiments  in  Sumatra. 

There  are  few  records  of  actual  increase  in  girth  consequent 
on  the  apphcation  of  artificial  manures,  though  no  one  doubts  that 
better  growth  is  obtained  by  their  use,  especially  on  poor  soil. 
Cowie  (I.R.J.,  April,  1909),  reports  the  following  experiment  at 
Deli-Moeda,  East  Coast  of  Sumatra.  Commencing  in  October, 
1906,  at  which  time  the  trees  (Hevea)  were  two  years  ten  months 
old,  three  plots  of  land  were  taken  and  differently  treated  from 
a  manurial  point  of  vi^w.  At  the  end  of  two  years  the  circum- 
ferences of  the  trees  on  the  different  plots  were  measured,  at  one 
yard  above  the  ground,  and  the  average  for  each  plot  was  calcu- 
lated.    The  results  are  shown  as  follows  : — 

I.  II.  III. 

No  Completely  Manured.       Manured  without 

Manure.  Potash. 

2  lb.  Pea-nut  Cake         2  lb.  Pea-nut  Cake 
Manuriilg  per  —  Meal.  Meal. 

tree.  12  oz.  Double  Super-     12  oz.  Double  Super- 

phosphate, phosphate. 

8  oz.  Muriate  of  Potash. 

Average  girth.  9  inches.  14  inches.  12  inches. 


170  PARA     RUBBER 

From  the  results  of  these  and  other  experiments,  it  is  clear 
that  potash  may  be  made  to  play  a  very  important  part  in  the 
manuring  of  rubber.  While  this  ingredient  may  be  applied 
fairly  abundantly  with  advantage,  nitrogen  must  be  used  with 
a  little  more  caution,  in  order  to  prevent  a  too  luxuriant  growth  of 
foliage.  Phosphoric  acid  is  also,  of  course,  indispensable,  and 
although  it  may  not  benefit  the  wood  to  the  same  extent  as  potash, 
it  serves  like  it  to  counteract  the  excessive  stimulating  effect  of 
nitrogen  on  the  development  of  the  foliage. 

Leplae  states  (T.A.,  May,  1910),  that  on  an  island  in  the 
Rio  Archipelago,  off  Sumatra,  applications  of  nitrogenous  manures 
on  clay  soils  were  doing  good  for  trees  in  their  second  year.  And 
as  much  as  1  lb.  of  guano  was  applied,  per  tree,  on  some  young 
Hevea  plantations. 

Manurial  Experiments  in  Ceylon. 
Experiments  with   artificial   and  green    manures  have  been 
made  at  Peradeniya  on  the  trees  planted  by  me  in  1905,  which 
show  the  effect  of  these  manures,  and  also,  incidentally,  of  catch- 
crops. 


Average 

girth 

in  inches. 

Increase 

Plot. 

Manure  or  Crop. 

Dec.  1908. 

Oct.  1909. 

in  inches. 

78 

Soluble  manure 

1027 

14-46 

4-i8 

79 

Crotalaria  striata 

9-96 

13-76 

3-80 

80 

Lemon  grass 

7'97 

ii-ii 

3'15 

81 

Indigofera 

9-27 

13-38 

4-12 

82 

Blank  (control) 

9-58 

13-28 

370 

Another  experiment,  carried  out  by  Mr.  Eckert,  Mncit, 
Ruawella,  shows  the  evil  effect  of  an  ill-balanced  manure.  A 
mixture  of  castor  and  rape-cake,  crushed  fish,  blood  and  bone 
meal,  and  muriate  of  potash,  containing  15  per  cent,  of  potash, 
4-5  per  cent,  of  phosphoric  acid,  and  4-5  per  cent,  of  nitrogen, 
gave  a  healthy  tree.  But  a  mixture  of  the  same  substances 
containing  5  per  cent,  of  potash,  4-9  per  cent,  of  phosphoric  acid, 
and  5-7  per  cent,  of  nitrogen — one  with  excess  of  nitrogen  com- 
pared with  potash — gave  a  weak-wooded  tree  with  heavy  foliage 
crown,  so  that  the  stem  was  easily  bent  over  and  even  broken. 

Manurial  Experiments  in  Malaya. 

The  following  experiments  are  recorded  (Str.  Bull.,  Aug., 
1 910)  on  Umbei  Rubber  Estate,  Malacca  : — 

Number  of       Average  girth  in  inches.  A\'erage  increase 
Manure  applied.  trees.         March  19th,      June  igth,  in  inches. 

1910.  igio. 

Bone  meal  60  6-34"  7"2o"  o'95' 

Fish  manure  60  6-25'  7"3o'  105" 

No  manure  (control)  59  a'?^"  6-70'  0-98' 

Half-a-pound  of  manure  was  applied  to  each  tree,  and  it  is 
quite  probable  that  the  whole  effect  was  not  registered  in  the 
three  months'  interval  shown  in  the  above  statistic. 


PARA     RUBBER 


171 


Ridley  (Straits  Bulletin,  October,  1904),  treated  each  of  five 
rows  of  nursery  plants  differently.  The  rows  received  respectively 
burnt  earth  and  leaves,  burnt  earth  and  leaves  with  cow-dung, 
cow-dung,  poudrette  and  lime.  Manuring  with  cow-dung  gave  the 
best  results,  and  burnt  earth  came  next.  Lime  seemed  absolutely 
injurious.  Ridley  points  out  that  cow-dung  is  too  expensive 
to  use  on  a  large  scale,  but  he  suggests  its  use  in  the  nurseries. 

Mathieu  (Trop.  Agric,  Sept.,  1910)  performed  some  manuring 
experiments  on  an  estate  in  Singapore  with  two-year-old  plants. 
The  records  published  so  far  deal  with  a  period  of  only  four  months, 
and  though  the  experiments  are  not  conclusive,  they  undoubtedly 
prove  that  a  greatly  accelerated  growth  is  obtained  by  giving  each 
tree  of  that  age  two  pounds  of  a  mixture  of  which  the  composition 
is  roughly  given  as  follows  :  sulphate  of  ammonia  and  super- 
phosphate, 55  lb.,  muriate  of  potash  and  bone  meal,  25  lb. 

Manurial  Experiments  with  Hevea  in  Hawaii. 

To  test  the  effects  of  different  fertilisers  on  Hevea  in  soil 
of  the  experimental  station  type — of  which  an  analysis  is  not 
given — Miss  Thompson  (Annual  Report,  Hawaiian  Agric.  Exper. 
Station,  1908)  used  the  paraffined  wire-basket  method.  Seeds 
were  planted  in  wire-baskets  filled  with  soils  containing  various 
manure  mixtures.  The  whole  was  sealed  with  a  film  of  paraffin 
wax,  except  for  an  aperture  allowing  the  plants  to  grow  out  and 
allowing  the  soil  to  be  watered,  the  latter  being  done  daily  with 
a  known  quantity  of  water.  The  table  below  shows  the  average 
weight  of  the  plants  after  they  had  been  allowed  to  grow  a  httle, 
and  it  also  shows  the  average  transpiration  of  water,  which 
might  conceivably  be  a  measure  of  the  activity  of  the  plant. 

Amount 


Check  (unmanured) 

Superphosphate 

Sulphate  of  potash 

Nitrate  of  soda    .  . 

Lime 

Manure  (dry) 

Superphosphate  and  sulphate  of  potash 

Superphosphate  and  nitrate  of  soda     . . 

Nitrate  of  soda  and  sulphate  of  potash 

Superphosphate,  lime,  nitrate  of  soda, 

and    sulphate    of    potash     (Ume, 

2,ooolb.) 
Superphosphate,  nitrate   of   soda,  and 

sulphate  of  potash  .  . 

The     following     are     Miss 
dry   manure,   sodium   nitrate,    or 

increased  materially  ;  superphosphate  or  sulphate  of  potash  gave 
a  slight  increase  ;  superphosphate  with  sulphate  of  potash  gave 
a  large  increase  ;  but  superphosphate  in  the  other  combinations 
either    decreased    the    transpiration  or  gave  but    little  increase. 


applied. 

Average 

Average 

calculated 

Transpira- 

weight of 

per  acre. 

tion. 

Plant. 

lb. 

grams. 

grams. 

— 

10-95 

3'I4 

200 

il'56 

3-42 

200 

1 1 '42 

3-55 

200 

16-58 

3-90 

2,240 

I3'05 

3-22 

11,200 

I5-50 

3-56 

200  each 

17-16 

3-83 

200  each 

10-50 

3'40 

200  each 

13-20 

3-29 

200  each 

7-06 

2-45 

220  each 

12-35 

3-i8 

lompson's 

comments 

with 

ime   alone. 

the  transpiration 

172 


PARA    RUBBER 


Sodium  nitrate  used  alone  is  a  good  fertiliser  for  rubber  trees, 
while  superphosphate  has  some  deleterious  effect. 

It  is  very  difficult  to  form  any  conclusions  from  the  above 
regarding  the  comparative  value  of  the  manures  employed  in 
these  experiments. 

Constituents  in  Woody  Stems,  Twigs,  and  Leaves. 
In  order  to  furnish  some  idea  of  the  constituents  of  various 
parts  of  the  rubber  tree,  the  following  synopsis  is  given  of  the 
constituents  of  the  fresh  material  (Circular  R.B.G.,  No.  6) : — 
Analyses  of  Parts   of  Hevea  Tree   dried   at   100°  C. 
Decayed 


Fresh 

Fallen 

Fallen 

Leaves. 

% 

Leaves. 

% 

Stalks. 
% 

Wood. 
% 

Twigs. 

% 

Water 

.  .      70 

.     60 

.      60 

.     60 

50 

Ash 

4-69 

4-08 

3-i8       . 

3-12 

262 

Lime 

0-51 

1-40 

o-8o 

o-8o 

0-83 

Magnesia    .  . 

o'56 

0-89 

0-30 

.        0-15 

0-17 

Potash 

1-72       . 

0-54 

0-64 

0-30 

0-28 

Phosphoric  acic 

0-66 

0-30 

0-15       . 

018 

0-09 

Nitrogen     . . 

3'44       • 

I -92 

0-84 

0-59 

0-62 

Composition  of  Artificial  Manures. 

The  following  table  shows  the  constituents  of  common  artificial 
manures  obtainable  from  local  merchants,  and  the  compositions 
here  quoted  are  those  guaranteed  by  various  firms  in  Colombo  : — 


Manure. 

Potash. 

Phosphoric  Acid. 

Nitrogen. 

0/ 

/o 

% 

% 

Blood  meal 

10  to  14 

Groundnut  cake 

I   to   2 

I  to  2 

7*  to    9 

Castor  cake      . . 

I  to  2 

I  to  2 

6to  7 

Rape  cake 

T  to  2 

2  to  3 

5  to  6 

Nitrate  of  soda 



— 

15  to  16 

Sulphate  of  ammonia 



— 

20J  to  21 J 

Chloride  of  potash 

•      57  to  59 

— 

— 

Sulphate  of  potash     . . 

■      49  to  52 

— 

— 

Precipitated  phosphate  of  lin 

le         — 

35  to  40 

— 

Concentrated  superphosphal 

e          — 

44  to  46 

— 

Basic  slag 

— 

I9-J  to  21 

— 

Fish 

— 

4  to  6 

5ito    6i 

Bone  dust 

— 

23  to  24 

3*  to     4 

Nitrate  of  potash 

•      37  to  40 

I  I  to  1 3 

Kainit  . . 

•      13  to  15 

— 

— 

Manure  Mixtures. 

The  following  mixtures  have  been  recommended  : — 

Mixture  I. 
This  is  suitable  for  land  rich  in  nitrogen  and  where  there  is  a  good  leaf 
growth. 


28  per  cent,  muriate  of  potash 

25  per  cent,  superphosphate 

20  per  cent,  bonemeal 

17  per  cent,  oilcake    .  . 

10  per  cent,  sulphate  of  ammonia 


Potash. 

% 
14 

Phosphoric 
acid. 

% 

Nitrogt 

% 

— 

450 
560 

02 

— 

— 

i'3 

— 

— 

1-6 

100  per  cent,  contains 


14 


3"i 


400  to  800  lb.  per  acre  to  be  applied. 


PARA     RUBBER 


Mixture  II. 


173 


This  is  recommended  for  land  which  is  in  a  poor  condition  with  regard  to 
its  nitrogen  content. 

Phosphoric 

Potash.             Acid.  Nitrogen. 

%                    %  % 

20  per  cent,  muriate  of  potash           . .            10                   —  — 

30  per  cent,  superphosphate              ..           —                   5-4  — 

10  per  cent,  bonemeal            ..          ..           —                   2'8  o-j 

24  per  cent,  sulphate  of  ammonia     ..           —                   —  49 

16  per  cent,  oilcake     ......           —                   —  i-o 


100  per  cent,  contains  ..  ..  10  8'2  6-o 

400  to  700  lb.  per  acre  to  be  applied. 

The  mixture  below  has,  according  to  Johnson,  been  found 
to  yield  good  results,  and  may  be  modified  to  suit  particular 
requirements  :  basic  slag,  1,500  lbs.  ;  nitrate  of  soda,  250  lbs.  ; 
sulphate  of  potash,  250  lbs.  This  should  be  applied  at  the  rate 
of  about  300  lbs.  per  acre,  and  ploughed  or  harrowed  in. 

Turning    Weeds    into    the    Soil. 

When  estates  are  planted  with  rubber  alone  one  must  either 
elect  to  allow  the  clean-weeded  soil  to  be  exposed  to  the  sun  and 
rain  and  to  be  thereby  impoverished,  or  decide  to  protect  it  by 
a  green  crop  and  increase  the  organic  matter  and  mineral  con- 
stituents for  the  future  benefit  of  the  growing  rubber. 

In  many  countries,  especially  Java  and  certain  West  Indian 
islands,  weeds  are  frequently  allowed  to  grow,  and  are  periodically 
cutlassed  and  applied  as  a  mulch  on  the  surface  or  turned  into  the 
soil.  If  we  could  select  our  own  weeds,  or  feel  fairly  certain  that 
lalang  or  its  equivalent  would  not  gain  a  footing,  we  might  be 
excused  for  allowing  other  weeds  to  grow.  Even  then  it  must  be 
admitted  that  the  growth  of  the  Hevea  trees  is  likely  to  be  retarded. 
It  is  difficult  to  explain  the  very  slow  rate  of  growth  of  Hevea 
trees  on  weedy  land  except  by  assuming  that  the  growing  crop 
of  weeds  takes  up  plant  food  which  might  otherwise  have  been 
absorbed  by  the  Hevea  rootlets,  and  checks  the  circulation  of 
air,  water,  and  plant  food  in  all  directions  through  the  soil. 

Green   Manuring   for   Hevea  Trees. 

It  is  hardly  necessary  to  point  out  the  advantages  of  green 
manuring,  seeing  that  the  system  is  adopted  in  European  as  well 
as  tropical  countries.  One  great  advantage  attending  the  use  of 
the  plants  mentioned  below  lies  in  the  fact  that  they  are  able,  in 
virtue  of  the  bacteria  associated  with  the  nodules  on  the  root,  to 
absorb  nitrogen  direct  from  the  air,  a  capacity  not  possessed  by 
most  of  the  plants  under  cultivation. 

The  points  to  be  considered  are :  during  what  stage  in  the  life 
of  a  rubber  plantation  green  manures  can  be  cultivated,  and  which 
plants  are  best  suited  for  the  purpose.     It  is  unnecessary  to  explain 


174  PARA     RUBBER 

that  after  a  good  rubber  estate  is  six  to  eight  years  old,  green 
manuring  must  practically  cease. 

Disadvantages   of   Green    Manures. 

Though  no  one  can  doubt  the  benefits  accruing,  to  the  soil, 
from  the  use  of  green  manures,  there  are  many  disadvantages 
which  cannot  be  lost  sight  of.  Firstly,  they  may  lead,  if  grown  on 
the  land  where  they  are  used,  to  serious  disorganization  of  the 
weeding  labour  force  and  lalang  may  estabUsh  itself  ;  secondly, 
they  may  harbour  pigs,  rats,  porcupines,  and  may  lead  to  the 
spread  of  pests  through  the  plantation,  and  increase  the  risk 
of  fire  ;  lastly,  their  regular  cultivation  may  be  very  expensive 
and  still  retard  the  growth  of  the  Hevea  trees.  No  one  can  deny 
that  many  estates  have  been  almost  ruined  by  allowing  weeds  to 
get  out  of  hand,  and  the  system  should  not  be  considered  if  the 
estate  is  already  clean-weeded.  It  is  wiser  to  maintain  a  clean- 
weeded  estate  in  that  condition,  and  buy  green  and  artificial 
manures  on  the  market  for  application  to  the  soil.  On  weedy 
or  steep  estates,  or  on  properties  that  cannot  be  kept  clean,  the 
subject  is,  nevertheless,  of  some  importance. 

Herbaceous  Plants. 

Herbaceous  plants  can  be  best  grown  from  the  first  to  the  fourth 
year  on  account  of  the  abundance  of  light  they  are  able  to  obtain 
and  the  relative  freedom  of  the  soil  particles  from. the  roots  of 
other  plants.  The  plants  which  can  be  used  are  Crotalaria  striata, 
C.  lahurnifolia,  C.  incana,  Cajanus  indicus.  Mimosa  pudica, 
Desmodium  trifolium,  Tephrosia  purpurea,  and  species  of  Indigofera 
and  Cassia.  These  plants  are  shrubby  in  habit,  grow  to  a  height 
of  one  to  five  feet,  and  will  stand  pruning  at  intervals  of  four  to  six 
months.  Indigo  appears  to  be  favoured  in  many  parts  of  Java 
and  Malaya.  Trailing  or  creeping  plants  such  as  the  groundnut 
and  species  of  Vigna  can  be  successfully  grown,  and  also  the 
Sensitive  plant.  All  these  plants  give  a  good  cover  to  the  soil 
and  help  to  keep  the  weeds  in  check  ;  they  produce  large  quantities 
of  organic  matter  rich  in  plant  food.  Space  forbids  a  fvill  account 
of  this  subject,  but  the  following  facts  are  of  interest  as  showing 
the  weight  of  green  material  obtainable  and  its  composition  in 
several  species  : — 

Weight  of  Organic         Time  between  Sowing 
Name  of  Plant.  Matter  per  Acre.  and  Uprooting. 

Crotalaria  striata  ..  20,2441b.  ..         Ten  months 

Vigna         12,092    ,,  ..         Four  months 

Pondicherry  groundnut  ..  ..  4,692    .,  ..  Five  months 

COMPOSITION  OF  Various  Green  Plants,  in  the  Fresh 
State. 

Nitrogen.            Potash.  Phosphoric  Acid.  Ume. 

Name  of  Plant.                 %                       %  "/^                         % 

Crotalaria  striata            ..o-7toi-o  ..       0^47  ..       0-154        ■•  0-210 

Vigna 0-6  ..       0-738  ..       0-177        ••  0-727 

Pondicherry  groundnut        0-914                  0-493  ..       0-155        ••  0-242 


PARA     RUBBER  175 

It  is  interesting  to  work  out  what  is  the  equivalent  of  15,000  lb. 
of  green  manure  of  Crotalaria  striata  from  a  purely  theoretical 
standpoint.  According  to  the  above  analyses  it  is  approximately 
equal  to  a  manure  of  the  following  composition  : — 

lb. 
Castor  cake  .  .  .  .  . .  500 


Blood  meal  .  . 
Nitrate  of  soda 
Basic  slag     .  . 
Potassium  sulphate 


500 

140 

115 
140 


If  the  whole  of  the  material  is  to  be  used,  it  should  be  buried 
with  lime  or  basic  slag  around  the  trees,  or  forked  in  as  previously 
explained.  During  its  decomposition  it  leads  to  the  liberation  of 
large  quantities  of  plant  food,  which  would  otherwise  remain  in  a 
latent  stage  for  many  years. 

For  the  successful  cultivation  of  the  herbaceous  green  manures 
about  10  to  20  lb.  of  seed  per  acre  should  be  broadcasted  on  clean 
land  in  wet  weather  and  the  land  lightly  forked.  In  Fiji  as  much 
as  50  lb.  of  Vigna  seed  is  used  per  acre  in  connection  with  other 
products.  The  green  manure  seeds  should  be  sown  a  reasonable 
distance  from  the  Hevea  trees  in  order  to  permit  of  ordinary 
daily  inspection.  On  steep  land  they  should  be  sown  at  right 
angles  to  the  slope  to  check  soil  wash  as  much  as  possible. 


Tree   Forms. 

The  cultivation  of  trees  for  green  manure  is  only  possible  on 
young  rubber  estates  ;  their  adoption  does  not  endanger  the 
weeding  work  on  the  estate  as  in  the  case  of  herbaceous  types — 
generaUy  their  growth  renders  the  weeding  problem  less  difficult 
on  account  of  the  shade  given  by  the  foliage. 

The  best  tree-forms  to  use  for  green  manure  are  Dadaps 
(Erythrina  sp.)  and  Alhizzia  moluccana.  <  Dadaps  can  be  propa 
gated  from  cuttings.  In  some  districts  they  will  give  a  very 
large  amount  of  organic  matter  within  a  few  months  from  planting 
the  cuttings.  Plants  can  also  be  used,  though  the  organic  matter 
obtainable  from  them  within  a  couple  of  years  is  less  than  that 
from  cuttings  in  a  few  months.  If  cuttings  are  used,  they  can  be 
planted  between  every  two  rubber  plants.  The  best  results  are 
obtained  if  the  cuttings  are  about  two  inches  in  diameter  and  four 
feet  long  with  one  foot  below  ground  ;  they  should  be  planted 
in  very  wet  weather.  Dadaps  can  be  used  on  hillsides  where  the 
cultivation  of  herbaceous  green  manures  is  practically  impossible. 
They  should  be  lopped  or  hand-pruned  as  frequently  as  possible 
and  the  material  buried  in  the  same  manner  as  for  other  species. 
The  following  table  shows  the  weight  of  fresh  leaves  obtainable 
from  one  acre  of  Dadap  cuttings  planted  4  by  8  feet  apart  in  July, 
1904. 


176 


PARA    RUBBER 


November,  1904 

December 

March  1905 

April 

May 

June 

July 

August 

September 

November 

December 


Total 


lb. 
791 
967* 
1.935 
1 .4441 
2,255 
2,240 
2,180 
3.058 
1.569! 
2, 104  J 

i,653i 
20,198^ 


These  experiments  show  that  Dadap  cuttings  may  produce 
over  18,000  lb.  of  fresh  green  leaves  within  one  year  from  planting, 
and  the  leaves  may  be  hand-pruned  nearly  every  month  in  the 
year.  The  fresh  leaves  contain  0-3  to  o-8  per  cent,  of  nitrogen, 
0-148  per  cent,  of  potash,  o-o8  per  cent,  of  phosphoric  acid  and 
0-197  P^r  cent,  of  lime. 

Albizzia. 

Albizzia' moluccana  is  one  of  the  quickest-growing  trees  known, 
but  it  is  not  easily  propagated  from  cuttings.  The  woody  tissues 
preponderate,  and  the  weight  of  leaf  obtainable  within  one  or  two 
years  is  less  than  with  Dadaps.  The  leaves  are  a  valuable  plant 
food,  and  if  the  trees  are  regularly  lopped  will  give  a  fair  amount  of 
material  fit  to  be  buried.  A  one-acre  plot,  planted  in  July  1904,  20 
feet  apart,  gave  up  to  January  1906,  3,246  lb.  of  green  material  and 
woody  twigs,  so  that  if  planted  as  close  as  the  Dadaps  (8  by  4)  they 
should  yield  about  13,000  lb.  per  acre  per  year.  On  some  rubber 
estates  the  young  Albizzia  plants  have  been  so  pruned  as  to  be 
easily  overtopped  by  two-year-old  rubber  trees,  the  branches  and 
foliage  of  the  Albizzia  trees  covering  the  greater  part  of  the  soil. 
The  fresh  leaves  contain  0-395  per  cent,  of  nitrogen,  0-406  per  cent, 
of  potash,  0-178  per  cent,  of  phosphoric  acid,  and  0-441  per  cent,  of 
lime. 

If  it  is  found  necessary  to  plant  belts  of  trees  enclosing  various 
sections  of  a  rubber  estate  for  the  purpose  of  checking  the  spread 
of  disease,  the  possibiUty  of  using  mixed  lines  of  Dadap  and 
Albizzia  trees  should  be  worth  considering ;  the  former  can 
be  easily  pruned  and  made  to  produce  a  close,  low-lying,  bushy 
fence,  and  the  latter  allowed  to  grow  and  form  a  belt  of  foliage 
and  branches  above  the  tops  of  the  Dadap  plants. 

'     Green    Manuring    in    Malaya. 

Ridley  maintains  that  in  the  Straits  and  F.M.S.  manuring  the 
trees  by  the  trenching  system  or  the  interplanting  of  Hevea 
trees  with  Dadaps  is  not  to  be  recommended  as  it  involves  an 
interference  or  destruction  of  the  roots  and  cutting  out  of  the  trees 
at  a  later  date.  He  is  of  the  opinion  that  green  manuring  in  the 
Straits  and  F.M.S.  should  be  done  only  with  herbaceous  plants. 


PARA     RUBBER  177 

and  these  should  be  merely  cut  and  thrown  on  the  ground  and  not 
dug  in.  In  Malaya  very  little  green  manuring  is  done.  In  Java, 
where  the  soil  is  equally  rich,  the  system  is  frequently  tried  with 
varying  degrees  of  success. 

A  number  of  experiments  have  been  made  in  the  F.M.S.  A 
planter  states  (Str.  Bull.,  April,  1909),  that  the  following  is  the 
cost  of  cultivating  Tephrosia  purpurea,  and  he  compares  it  with 
clean-weeding,  as  follows  : — 

$IO0"00 


Clean-weeding,  for  5  years 
Tephrosia. 

per 

acre. 

I  St  year — 
Establishing 
Keeping  drains  clear 
Rent  (!)     .  . 

$ 
4'oo 
i-oo 
i-oo 

Cutting  down  twice 
Various    . . 

2-0O 

I  00 

Superintendence 

100 

2nd  to  5th  years — 

As     above     (less     cost 

of     es 

tablishing)    . . 

24.00 

—  $io'oo 


$24'00 

3400 

In  the  above  it  is  assumed  that  the  crop  is  more  or  less  self- 
seeding  ;  to  rely  upon  the  plant  doing  this  effectively  would 
be  risky.  No  mention  is  made  of  the  cost  of  weeding  before  and 
after  each  green  manure  crop  ;  information  on  this  point  is 
essential  before  one  can  recommend  this  cultivation. 

Campbell  (Report,  1908),  after  conducting  numerous  ex- 
periments has  arrived  at  the  following  conclusions  : — 

Crotalaria. — The  best  method  of  planting  is  as  follows  :^ 

(i)  For  hill  lands,  or  any  ground  with  hard  surface  :  holes 
cut  one  changkol  deep,  about  15  inches  apart,  and  dibble  the 
seeds  in. 

(2)  For  ordinary  slightly  undulating  land  :    dibble  seeds  in. 

(3)  On  land  with  loose  surface  :  sow  seeds  broadcast  (2  lb. 
per  acre)  and  rake  in. 

(4)  On  wet,  low-lying  land  :  sow  seeds  broadcast  (2  lb.  per 
acre). 

Mimosa  pudica. — This  has  been  grown  over  six  acres  in 
Batu  Tiga,  where  it  has  made  a  dense  cover  and  keeps  in  check  all 
weeds  except  lalang.  Where  lalang  was  already  present,  the 
ground  was  dug  up  and  the  roots  picked  before  the  plants  were 
put  in.  The  lalang  in  some  cases  grew  rapidly,  and  threatened 
to  kill  the  mimosa.  In  some  places,  where  there  was  no  lalang 
before  planting,  none  has  come  up. 

Three  plots  with  mimosa,  10  months  old,  were  cut  down  to 
6  inches  and  the  cuttings  weighed  ;  the  average  weight  of  mulching 
material  worked' out  at  2,950  lb.  per  acre. 

Passiflora  foetida.^This  grows  rapidly  on  low-ljdng  moist 
land,  but  the  growth  is  slow  on  hard  ground,  especially  in  districts 
subject  to  occasional  drought. 


178  PARA     RUBBER 

Recent  Experiments  in  Ceylon  on  Soil  Wash. 
The  loss  of  soil  on  land  clean-weeded  is  known  to  be  great 
and  to  vary  when  covered  by  various  green  manures.  Ex- 
periments were  commenced  in  Ceylon  in  March,  1909  (T.A., 
Sept.,  1910),  to  determine  the  loss  of  surface  soil  by  wash  on 
average  sloping  land.  The  soil  wash,  in  tons  per  acre,  from 
March,  1909,  to  March,  1910,  on  the  various  plots,  was  as  follows  : — 

Clean-weeded      115     tons. 

Dadaps     106 

Deep-forked  land    79 

Albizzia    67 

Ipomea     45 

Crotalaria,  across  slope      43J     ,, 

Crotalaiia  and   Indigofera  in  rows  i  foot 

apart  up  slope     26  j 

Crotalaria,  across  slope  i  f oot  apart 26 J     , , 

Desmodium    12  J 

The  rainfall  during  the  period  of  the  experiments  was  59-03 
inches. 

It  is  generally  acknowledged  that  the  soil-wash  under  arbores- 
cent (Dadaps,  Albizzia),  shade  is  greater  than  that  under  her- 
baceous types  (Crotalaria,  Ipomea).  The  foregoing  results  may 
be  materially  altered  as  the  experiment  proceeds,  but  the  loss 
on  land  deeply-forked  is,  meanwhile,  of  more  than  passing  interest 
to  planters  whose  estates  are  steep. 


CHAPTER  IX. 

TAPPING  OPERATIONS  AND  IMPLEMENTS. 

The  question  of  tapping  Hevea  rubber  trees  is  one  which 
deserves  special  consideration  and  is  not  outweighed  in  importance 
by  even  the  methods  of  planting  or  by  the  processes  of  curing  the 
raw  rubber.  On  the  methods  of  tapping  depend  not  only  the 
quality  and  quantity  of  the  latex  and  rubber,  but  the  life  and 
future  condition  of  the  trees. 

In  the  case  of  Hevea  hrasiliensis  we  are  concerned  with  the 
laticiferous  tubes  in  the  outer  part  of  the  stems — the  secondary 
cortex — when  the  trees  are  ready  for  tapping.  The  thickness  of 
this  tissue  may  vary  from  \  to  about  \  inch  or  more,  according  to 
the  age  of  the  tree. 

The  average  thickness  of  the  undisturbed  bark  of  twenty-year- 
old  trees  in  Ceylon  is  about  |  inch  (9-5  mm.),  though  trees  at 
Singapore,  only  11  years  old,  possess  bark  of  this  thickness.  The 
outer  part  to  a  depth  of  \  inch  (3  mm.)  does  not  contain  many 
tubes  charged  with  latex,  but  the  inner  part  has  a  large  number, 
and  from  the  inner  xV  to  ^\  inch  the  latex  mainly  flows.  The  latex 
tjibes  in  the  outer  part  dry  up  and  are  regularly  shed  with  the 
outer  bark  tissues. 

When  the  primary  cortex  has  been  removed  new  tissue  is- 
produced,  mainly  from  above  downwards  and  within  outwards, 
and  in  this  the  latex  tubes  ^rise  de  novo  as  in  the  original  material. 
It  is  important  to  remember  that  the  extension  of  these  tubes  in 
the  cortex  of  Hevea  is  a  gradual  one,  that  in  many  instances  the 
parts  of  the  laticiferous  system  are  not  extensive,  and  in  tapping 
operations  only  a  fraction  of  the  whole  of  the  latex-containing 
tubes  may  be  drawn  upon. 

Recent  experiments  have  shown  how  improvement  can  be 
.made  on  the  old  method  of  tapping  every  alternate  year  and 
obtaining  i-|-  lb.  of  rubber  per  tree,  per  year,  from  eleven-year-old 
trees.  The  yield  obtained  in  parts  of  the  East  shows  that  by 
somewhat  drastic  methods  it  is  possible  to  procure  from  particular 
trees  in  one  year's  tapping  as  much  as  the  most  sanguine  only  a 
few  years  ago  anticipated  in  ten  years'  tapping,  though  it  must  be 
borne  in  mind  that  the  effect  on  the  trees  cannot,  with  our  present 
knowledge,  be  accurately  forecasted,  and  may  or  may  not  prove 
to  be  detrimental. 

Effect  of  Bad  Tapping. 

It  is  more  than  likely  that  the  tappirig  implements  and 
methods  of  the  future  will  be  such  as  to  ensure  tha+  the  minimum, 
if  any,  damage  is  done  to  the  cambium.     With  all  due  respect  to 


i8o  PARA    RUBBER 

many  inventors  who  have  placed  their  knives  before  the  pubUc, 
it  may  be  stated  that  the  faultless  or  ideal  paring  implement  has 
not  yet  been  produced,  though  there  seems  every  hkelihood  that 
it  will  soon  be  on  the  market.  There  are  still  several  implements 
sold  and  used  which  should  be  classed  as  dangerous. 

In  faulty  tapping  severe  wounds  may  be  inflicted,  and  several 
years  after  the  injury  is  made,  the  parts  above  it  may  be  found  to 
be  very  hard  and  to  give  very  httle  latex.  In  one  particular  case 
the  outward  appearance  was  not  striking  in  any  way,  and  only 
the  poor  yield  of  latex  led  to  an  inquiry  which  revealed  the  extent 
of  the  permanent  injury  that  had  been  done.  In  all  cases  where 
the  wood  has  been  damaged,  the  decomposition  of  a  vital  part  of 
the  tree  has  been  set  up,  and  the  vigour  and  longevity  of  the  tree 
appreciably  affected.  I  have  seen  several  malformations  produced 
by  damaging  the  wood  while  tapping  ;  often  the  areas  become 
very  "warty"  and  present  a  series  of  very  large  balls  of  hard 
woody  tissue  incapable  of  being  tapped,  and  which  seem  to  rest 
in  sockets  of  the  timber  ;  in  other  cases  large  scars  exist  where  the 
chisel  has  cut  below  the  cambium.  The  injury  in  all  cases  is 
permanent  and  can  be  detected  many  years  after  it  has  been  made. 
Such  knobs  and  scars  are  not  due  to  ' '  canker, ' '  and  the  estabUsh- 
ment  of  a  smooth  surface  on  such  trees  without  cutting  into  the 
■wood  is  for  many  years  practically  an  impossibility. 

The  tapping  of  irregular  surfaces  requires  special  considera- 
tion ;  but  it  may  be  stated  that  in  no  case  should  the  woody  pro- 
tuberances be  excised  ;  the  incisions  should,  if  possible,  be  made 
above  or  below  all  woody  warts,  and  the  latter  allowed  to  work 
themselves  out  in  their  own  way  and  time.  In  such  cases  the 
zig-zag  method  of  tapping  can  often  be  adopted  with  advantage. 

Bad  Tapping  on  Old  Trees. 

The  Director  of  Agriculture,  Malaya,  stated  in  his  report  for 
1910  that  ' '  the  results  of  bad  tapping  will  be  noticeable  in  about 
four  years'  time  when  the  irregularly  renewed  surface  comes  to  be 
tapped  again  ;  the  tapping  will  then  be  very  difficult  to  carry  out 
and  still  more  difficult  to  carry  out  without  again  increasing  the 
damage.  Some  of  the  oldest  trees  in  various  places  in  the 
Federated  Malay  States  are  an  object  lesson  in  what  may  be 
accomplished  by  bad  tapping  ;  little  blame  can  be  attached  to 
the  original  workers,  who  had  to  learn  by  experience  how  to  tap 
and  how  not  to  ;  but  estates  with  trees  now  being  tapped  for  the 
first  time  should  profit  by  others'  experiences,  as  upon  the  quality 
of  the  present  tapping  a  good  deal  of  their  future  prosperity  will 
depend.  I  strongly  recommend  that  all  wounds  to  the  wood  in 
tapping  be  immediately  painted  with  cold  coal-tar.  This  draws 
attention  to  bad  tapping  and  saves  attack  by  wound-fungi  and 
borers." 

Knives  Made  on  the  Estate. 

That  a  scientific  implement  for  tapping  rubber  trees  is  not 
required  is  evident  from  a  study  of  results  obtained  in  Mala\'  by 


PARA     RUBBER  i8i 

knives  of  the  simplest  construction.  In  one  case  (I.R.J.,  August 
26th,  191 1)  it  was  reported  that  the  manager  of  the  Anglo- Java 
Rubber  Estates,  Ltd.,  had  been  able  to  make  his  own  tapping 
knives  on  the  estate  at  a  cost  of  6  cents  each  ;  these  implements, 
it  was  claimed,  were,  though  of  the  simplest  description,  capable 
of  excising  bark  shavings  from  30th  to  Jsth  of  an  inch  in  thick- 
ness. 

Requisites  of  a  Good  Tapping  Knife. 

The  various  methods  of  tapping  now  in  vogue  are  often 
associated  with  the  use  of  a  particular  knife  or  series  of  knives, 
and  it  is  therefore  necessary  to  consider  the  knives  commonly 
used  and  the  general  requirements  of  such  implements. 

There  are  several  points  which  should  be  borne  in  mind  by 
those  who  desire  to  effect  improvements  in  tapping  knives  or  to 
invent  new  ones. 

In  the  official  report  of  the  judges  at  the  Ceylon  Rubber 
Exhibition,  igo6,  the  following  points  were  considered  in  con- 
nection with  the  tapping  knives  exhibited  : — 

1.  Thinness  of  paring. — Under  this  head  the  judges  decided 
that  the  uniformity  of  the  section  ;  adjustability  ;  cleanness  of 
cut  or  absence  of  drag  ;  and  efficiency  of  the  guard  or  control  of 
the  section  were  points  of  practical  importance. 

2.  Convenience  and  fatility  in  operation. — In  this  group  the 
points  considered  related  to  the  muscular  effort  required  ;  visibility 
of  cut  during  tapping  operations  ;  capability  of  cutting  in  all 
directions  ;  suitability  for  unskilled  labour  ;  absence  of  clogging  ; 
and  prevention  or  impossibility  of  incorrect  use  by  cooly. 

3.  Simplicity  and  durability  : — These  items  necessitated  a 
study  of  the  price  ;  length  of  life  ;  retention  of  sharpness  ;  facility 
for  sharpening  ;   and  lack  of  complication  in  relation  to  each  knife. 

The  primary  considerations  are  as  follows  : — 
The  first  requisite  is  that  the  cutting  surfaces  shall  be  such 
as  to  enable  the  operator  to  either  make  an  even  clean  cut  or  to 
excise  the  cortical  tissues  without  dragging  the  cells  or  clogging  the 
knife.  Several  friends  have  shown  me  instruments  which  are  best 
described  as  surgical  scrapers,  planes,  and  closed  knives  ;  in  each 
case  the  idea  was  to  scrape  away  a  thin  film  of  the  cortical  tissue, 
but  in  every  instance  the  operation  dragged  the  cortical  cells 
considerably,  clogged  the  latex  tubes,  and  left  an  uneven  surface 
along  which  watery  latex  could  not  readily  flow.  A  clean  cut  is 
essential,  and  for  this  reason  it  is  doubtful  whether  the  principle 
of  scraping  will  ever  be  generally  adopted. 

A  second  point  of  very  great  importance  is  that  the  knife 
should,  if  possible,  be  provided  with  some  structure  which  will 
prevent  the  cooly  from  cutting  too  deep  when  making  the  initial 
excision,  and.  also  protect  the  cambium  during  subsequent  paring 
operations.  In  several  cases  separate  knives  are  used  for  making 
the  original  incision  and  subsequent  paring  operations  ;  those 
used  in  the  latter  processes  are  frequently  made  so  that  they  can  be 
adjusted  beforehand,  or  they  are  protected  by  a  fixed  or  detachable 


l82 


PARA     RUBBER 


blade.  It  is  generally  an  advantage  if  the  cutting  parts  can  be 
adjusted  with,  ease  and  replaced  without  great  expense,  but,  more 
often  than  not,  tools  which  are  adjustable  are  very  dangerous 
in  the  hands  of  coolies.  The  damage  done  by  many  adjustable 
knives  has  led  to  the  demand  for  non-adjustable  tools  which  are, 
as  far  as  possible,  fool-proof. 

A  third  consideration,  which  should  not  be  lost  sight  of,  is 
that  the  knife  should  be  one  which  can  be  used  in  cutting  from 
left  to  right  and  from  right  to  left  from  above  downwards.  This 
is  a  necessary  quahfication  in  all  tapping  methods  except  the 


YATES'S     "PULL    AND    PUSH"    KNIFE. 


right-hand  half-herring-bone  and  spiral  systems.  It  is  also 
advisable  that  knives  should  be  constructed  so  as  to  permit  of 
paring  being  done  by  ' '  pushing ' '  from  below  upwards  or  ' '  pulling ' ' 
from  above  downwards.  Such  knives  are  described  as  ' '  pull  and 
push"  implements. 

A  fourth  point,  which  has  obviously  received  attention  in 
many  knives  recently  put  on  the  market,  is  that  the  instrument 
used  for  re-opening  or  paring  the  lower  surface  of  the  wound 
should  be  so  constructed  that  only  the  minimum  quantity  of 
material  is  cut  away  at  each  operation.  The  longevity  of  the  tapp- 
ing area  depends  upon  this  operation,  and  at  the  present  time 
there  are  knives  capable  of  demolishing  twelve  inches  of  bark  in 
three  months,  and  others  which  will  not  use  up  the  same  quantity 
of  tissue  in  two  or  three  years.  The  very  narrow  cutting  margins 
of  several  knives  are  specially  devised  for  paring  away  very  thin 
shavings  of  the  bark.  The  thickness  of  the  parings  varies  from 
i-ioth  to  i-30th  of  an  inch,  20  to  25  parings  per  inch  being  con- 
sidered a  fair  average. 

The  introduction  of  pricking  instruments  for  cutting  the 
laticiferous  tubes  in  the  wound  area,  though  duplicating  the 
tools,  may  be  useful.  Generally  the  duplication  of  the  tools 
required  to  make  the  first  and  subsequent  incisions  is  undesirable, 
and  in  several  instruments  the  power  of  adjustment  is  such  as  to 
allow  all  the  operations  to  be  carried  out  by  means  of  one  knife 
only. 


PARA    RUBBER  183 

Paring  and  Pricking. 

The  amount  of  cortical  or  bark  tissue  removed  by  one  paring 
operation  is  sometimes  surprisingly  large.  The  average  cooly 
will  excise  the  lower  surface  until  a  large  number  of  white  globules 
of  latex  have  appeared,  when  by  the  use  of  other  implements  the 
latex  tubes  might  have  been  tapped  without  excising  any  cortical 
cells  at  all.  It  has  been  asserted  that  since  the  most  careful 
method  may  only  allow  one  to  tap  the  whole  of  the  surface  from 
the  base  up  to  six  feet  in  three  to  four  years,  the  care  advocated 
is  not  necessary  when  large  acreages  have  to  be  tapped.  But 
the  necessity  for  tapping  every  tree  on  a  large  plantation  is  no 
excuse  for  excising  the  cortical  tissues  in  a  wasteful  manner.  The 
best  results  will  accompany  those  methods  involving  the  removal 
of  the  minimum  amount  of  cortical  substance  during  tapping 
operations. 

It  has  been  urged  that  even  if  one  removes  large  quantities  of 
tissue  when  tapping,  the  rubber  can  still  be  extracted  from  the 
material  thus  removed.  This  is  correct,  especially  when  large 
quantities  of  bark  are  cut  away,  but  the  greater  part  of  the  rubber 
can,  by  proper  tapping,  be  removed  without  such  great  waste  of 
tissues. 

Furthermore,  it  should  be  distinctly  borne  in  mind  that  the 
removal  of  the  cortical  cells  means  the  destruction  of  living  tissues 
wherein  the  latex  tubes  arise.  The  actual  quantity  of  rubber  in 
the  cortex  at  any  particular  time  is  very  small  compared  with  that 
which  can  be  obtained  by  pricking  the  latex  tubes,  allowing  them 
to  become  refilled,  and  encouraging  their  development.  The 
use  of  pricking  implements  must,  however,  depend  on  the  ultimate 
effect  which  their  adoption  has  on  the  renewed  cortex  ;  this  will 
be  discussed  fully  in  a  later  chapter. 

Tapping  Knives. 

The  native  collectors  of  rubber  in  the  uncultivated  forests  of 
Brazil  use  an  axe-like  implement,  with  which  a  heavy  blow  can  be 
inflicted  and  all  the  tissues  from  the  bark  to  the  cambium  be  cut 
in  one  stroke  ;  this  implement  has  not,  however,  been  adopted 
in  the  middle  East,  owing  to  the  damage  inflicted  by  its  use. 

At  the  present  time  the  East  is  taking  a  very  active  interest 
in  inventing  and  improving  tapping  knives  for  use  in  obtaining 
latex  from  Hevea  rubber  trees,  and  the  following  accounts  of  some 
well-known  implements  will  be  of  value. 

The  Carpenter's  Chisel. 

This  was  used  in  the  early  tapping  days,  but  has  been  super- 
seded by  more  useful  tools.  Parkin  carried  out  experiments  to 
see  ' '  whether  incisions  made  with  a  stone  or  cold  chisel  gave 
more  latex  than  corresponding  ones  made  with  an  ordinary  chisel, 
but  did  not  find  any  appreciable  difference  in  the  amount  of  latex 
collected  from  the  two  kinds  of  incision  on  the  single  oblique 
pattern. ' '     He  finally  recommended  a  wedge-shaped  chisel  with 


i84  PARA     RUBBER 

a  thickness  of  3-i6th  to  J  inch  at  a  distance  of  |  inch  from  the 
cutting  edge  ;  the  breadth  of  the  chisel  varied  from  i  to  ij  in. 

The   Farrier's    Knife. 

This  knife  is  one  of  the  simplest  on  the  market  at  the  present 
time.  It  consists  of  a  long  piece  of  metal  turned  on  itself  at  the 
end  to  form  a  cutting  curve.  It  is  largely  used  on  some  estates 
in  Malaya  and  gives  satisfactory  results  when  the  coolies  have 
had  fair  experience.  There  is  hardly  any  limit  to  the  damage 
which  can  be  done  by  such  a  knife,  but  to  those  planters  who 
crave  for  simplicity  and  a  tool  which  cannot  be  adjusted  at  wiU 
by  the  coolies,  this  form  should  appeal.  A  double-edged  farrier's 
knife  is  also  being  used. 

Founded  upon  the  farrier's  knife  are  the  Jebong,  Johore,  and 
other  kinds. 

Gouges. 

The  gouge  is  largely  used  in  Malay  and  has  found  favour  on 
account  of  its  simplicity.  It  is,  like  the  farrier's  knife,  capable 
of  inflicting  dangerous  wounds,  but  it  is  little  less  than  marvellous 
to  see  how  skilfully  it  can  be  manipulated  by  properly-trained 
coolies.  Bark  shavings  having  a  thickness  of  from  i-25th  to  i-20th 
of  an  inch  can  easily  be  obtained  by  the  use  of  the  gouge  in  Malaya, 
where  patent  adjustable  tapping  knives  have  been  almost  entirely 
abandoned.  Some  gouges  are  straight  and  others  bent ;  the  latter 
are  often  preferred  except  for  very  old,  rough  bark.  Some  have 
the  edge  receding  or  hollowed  towards  the  handle  ;  others  have 
the  edge  projecting  and  forming  a  rounded  point.  The  gouge 
varies  in  width,  standard  sizes  being  J,  ^^,  f,.,,  and  |  of  an 
inch ;  the  i',.  inch  tool  appears  to  be  extensively  used  in  parts  of 
Malaya.  The  Director  of  Agriculture,  F.M.S.,  recently  stated  that 
' '  In  spite  of  numerous  new  inventions,  the  favourite  instruments 
are  still  the  simpler  tools,  the  gouge  (straight  or  bent)  and  the 
farrier's  knife  or  jebong.  Which  of  these  is  best  depends  reallv 
on  which  the  tapping  cooly  is  used  to.  Where  there  is  sufficient 
European  supervision  and  a  stable  labour  force,  the  tapping  in 
Malaya  is  usually  excellently  done,  with  consequent  good  renewal 
of  the  bark.  Where  one  or  other  of  these  conditions  does  not 
obtain,  it  is  common  to  see  wounds  right  down  to  the  wood. ' ' 

Surgical  Scrapers. 

With  the  idea  of  re-opening  the  wound  area  without  cutting 
away  a  large  quantity  of  tissue,  several  surgical  scrapers  and  planes 
have  been  brought  forward,  but  in  every  case  have  proved  unsatis- 
factory.    They  tend  to  clog  the  freshly-opened  latex  tubes. 

The  Beta  Knife. 

The  Beta  knife,  placed  on  the  market  by  Messrs.  T.  Christy 
&  Co.,  is,  according  to  Johnson,  a  useful  instrument  ;  the  length 
of  the  blade  is  regulated  by  means  of  a  screw  to  suit  the  varying 


PARA     RUBBER 


185 


thicknesses  of  the  bark  of  different  trees  and  so  prevent  its  damaging 
the  wood  of  the  tree. 

Golledge's  Knife. 

This  knife  is  a  chisel  with  the  end  in  the  shape  of  a  short,  sharp, 
bevelled   V,   and  a  cutting  groove  along  the   sides.     The    knife 


GOLLEDGE  S    KNIFE. 


can  be  used  for  making  cuts  from  above  downwards,  below  upwards, 
and  from  left  to  right  or  right  to  left.  It  can  be  used  to  make 
the  original  incision  and  during  subsequent  paring  operations. 

Holloway's  Knives. 

The  Holloway  tapping  tool  is  an  improved  V  knife  provided 
with  movable  blades.  The  V  head  is  fastened  to  the  handle  by 
two  small  screws  and  nuts,  and  the  blade  when  worn  down  is  easily 
replaced. 

Holloway  invented  another  knife  essentially  provided  with 
a  two-flanged  and  a  basal  cutting  surface.  The  blade  is  made 
of  metal  and  is  curved  like  a  hook  at  the  top  ;  the  cutting  area 
is  provided  with  a  flange  at  either  side  at  right  angles  to  the  base, 
and  all  parts  can  be  easily  sharpened.  The  basal  cutting  surface 
or  either  of  the  angles  can  be  used  in  making  the  original  incision, 
and'the  two  angles  may  be  used  for  paring  either  from  right  to  left 
or  left  to  right.  The  parts  are  changeable  and  all  operations  can 
be  done  with  one  implement. 

Mackenzie's  Knife. 

This  consists  of  a  tempered  steel  head  of  box  section  having 
cutting  edges  on  three  sides.  The  cutting  surfaces  are  in  one  piece 
and  movable.  By  an  ingenious  screw  arrangement  the  depth  of 
the  cutting  edges  can  be  adjusted  according  to  requirements  by  two 
side  guards.  The  knife  can  be  used  for  tapping  from  left  to  right 
or  right  to  left.  When  the  incision  is  so  broad  that  the  guard  on 
the  upper  side  of  the  knife  does  not  rest  against  the  bark  on  the  top 
side  of  the  cut,  the  upper  guard  can  be  lowered  so  as  to  come  in 
contact  with  the  excised  area,  along  which  it  rubs  during  paring 
operations. 


i86  PARA    RUBBER 

Collet's  Knife. 

This  is  made  entirely  of  metal.  Running  down  the  handle 
and  coming  out  at  the  base  is  a  bluntly-pointed  piece  which  is 
inserted  in  the  bark  of  the  tree  to  be  tapped,  and  by  this  means 
the  depth  of  the  bark  is  measured.  The  blade  of  the  knife  is 
like  a  sharp  curved  gouge,  and  has  on  it  a  brass  support,  which 
is  set  at  an  angle  with  the  blade  and — before  cutting — is  adjusted 
at  a  definite  angle,  so  that  when  the  knife  is  in  use  and  the  brass 
support  resting  against  the  bark,  the  cut  can  only  go  as  deep  as 
it  is  set  for,  that  is,  the  depth  of  the  bark  measured  at  first  ;  by 
this  means  the  laticiferous  cells  are  reached,  but  the  cambium 
is  not  cut. 

The  "Para"   Rubber  Tapping  Knlfe -and  Chisel. 

The  ' '  Para ' '  tapping  knife  is  designed  for  making  the  first  cuts 
in  rubber  trees,  when  the  paring  process  is  intended  to  be  carried 
out  in  the  subsequent  tapping  rounds.  It  is  constructed  to  make 
incisions  on  the  left  and  right  of  the  perpendicular,  and  after  these 
cuttings  to  leave  flat  surfaces  on  the  lower  sides  of  the  incisions. 
It  provides  ample  head  room  for  the  "Para  Chisel"  to  work 
in  during  the  early  rounds  of  paring.  The  "Para  Chisel"  is  a 
tool  for  re-opening  the  original  incision  in  such  a  manner  as  to 
renew  the  flow  of  latex  with  the  minimum  loss  of  bark  tissue. 
It  is  first  adjusted  to  cut  to  the  required  depth,  then  placed  in  the 
incision  and  pressed  gently  forward  in  a  direction  parallel  to  that 
of  the  incision.     The  cutting  blade  can  be  easily  renewed. 

Cater-Schofield  Knife. 

A  novelty  in  the  matter  of  the  grip  afforded  is  provided  in 
the  above-named  knife  (I.R.J.,  November  28th,  1910).  The 
grip  is  shaped  like  that  of  a  flat-iron  and  is  placed  immediately 
over  the  blade.  That  this  gives  a  better  control  of  the  action — 
compared  with  the  tools  where  the  blade  is  guided  from  a  point 
six  or  eight  inches  distant  from  the  centre  of  effort,  as  is  the  case 
with  the  ordinary  handle — appears  to  be  manifest,  though  I  have 
not  had  an  opportunity  of  testing  whether  this  is  so  in  actual 
practice. 

The  blades  provided  are  interchangeable,  easilv  fixed  and 
removed,  and  cheap  to  renew.  They  may  be  had  separately 
or  in  the  form  of  combined  reversible  incising  and  paring  blades. 

In  use  the  combined  blade  is  inserted  through  the  central 
aperture  in  the  platform  of  the  tool,  and  is  adjusted  to  the  required 
depth  and  angle.  The  angle  of  the  incising  blade  is  "started"  in 
a  small  hole  made  by  the  pricker,  and  the  complement  is  then 
drawn  firmly  round  by  the  operation.  The  result  is  a  clean-cut 
groove  or  channel,  the  floor  of  which  is  horizontal,  and  prevents 
the  latex  from  overflowing.  For  paring  it  is,  of  course,  only 
necessary  to  reverse  the  knife,  the  V-shaped  edge  being  thus 
replaced  by  a  straight-edged  "parer. " 


PARA     RUBBER  187 

Rollers  are  provided  on  which  the  tool  runs  smoothly  over 
the  bark.  The  distance  between  the  rollers  and  blade  being 
permanent,  the  cut  is  of  uniform  depth.  Having  once  set  the 
blade — depths  from  y,',  to  g  of  an  inch  are  allowed  for — the 
intended  depth  will  not  be  deviated  from. 

The  knife  is  adapted  to  all  the  well-known  systems  of  tapping. 

V   Implement   for   Tapping    Rubber   Trees. 

The  Eastern  Produce  and  Estates  Company  are  responsible 
for  a  knife  at  one  time  used  on  many  estates  in  Ceylon.  The 
patentee  claims  that  it  is  a  simple  knife  and  one  which  can  be 
economically  used  over  large  acreages  of  trees.  It  consists  of  a 
wooden  handle  of  suitable  size  and  shape,  furnished  at  one  end  with 
a  stabbing  or  piercing  point  for  the  purpose  of  clearing  the  old  cuts 
of  scrap  rubber.  It  is  occasionally  used  on  estates  for  piercing  the 
stem  or  newly-formed  cortical  tissiie  to  see  if  the  latex  is  abundant. 
The  cutting  device  is  mounted  at  the  other  end  of  the  handle  and 
consists  of  a  haft  or  stem  with  a  hollow  wedge  or  triangular-shaped 
cutting  portion  at  the  apex.  This  knife  was  one  of  the  first  to  be 
placed  on  the  market,  and  a  detailed  account  of  it  is  given  in  the 
India-Rubber  Journal  of  February,  1904. 

Bowman  and  Northway's  Knives. 

These  knives  were  continually  used  by  me  in  the  experiments 
at  Peradeniya  and  Henaratgoda,  and  in  response  to  suggestions 
the  originals  were  slightly  modified  in  order  to  be  of  use  in  any 
of  the  numerous  systems  of  tapping,  and  to  still  further  economize 
in  the  removal  of  the  cortical  tissues.  These  knives  appear  to 
have  been  superseded,  to  some  extent,  by  others,  but  they  are  of 
historic  as  well  as  practical  interest,  as  in  my  opinion  they  have 
been  the  basis  of  many  recent  inventions.  There  are  three  knives 
in  all :  No.  i  for  making  the  original  groove.  No.  2  for  re-opening 
the  lower  surface  of  the  wound,  and  No.  3  for  pricking  the  latex 
tubes  in  the  area  of  the  wound  response  without  removal  of  any 
cortical  tissue. 

Knife  No.  i  is  provided  with  a  two-edged  guide,  which,  on 
pressing  against  the  bark,  cuts  the  tissue  and  defines  the  area  to 
be  cut  away  by  the  knife  edge  behind  it.  By  this  means  the 
original  groove  shows  clean-cut  surfaces  above  and  below.  It  is 
used  much  like  a  plane,  the  head  being  suitably  adjusted  to  shave 
the  bark  gradually.  As  soon  as  the  proper  depth  is  reached,  the 
bark  is  of  a  white  colour  and  becomes  lighter  and  lighter  the  nearer 
one  gets  to  the  cambium,  so  that  by  practice  it  is  possible  to  tell 
almost  correctly  when  the  right  depth  has  been  cut. 

Young  trees  are  more  difficult  to  cut  to  the  correct  depth  than 
old  ones,  as  the  latex-bearing  tissues  below  the  bark  and  next  to 
the  cambium  are  very  thin  indeed.  It  is  therefore  advisable 
to  mark  lightly  with  No.  i  and  reach  the  correct  depth  gradually 
with  a  few  tappings  with  No.  2  in  the  manner  described  below 
for  cutting  deeper. 


i88  PARA     RUBBER 

Knife  No.  2  in  its  improved  form  is  very  ingenious.  The 
cutting  part  consists  of  three  surfaces,  a  narrow  basal  one  along 
which  a  spring  blade  is  inserted,  and  two  side  surfaces  at  right 
angles  to  the  basal  one.  When  the  flexible  spring  blade  is  in- 
serted, there  are  two  small  cutting  edges  available,  one  to  use 
when  cutting  from  right  to  left  and  one  for  use  from  left  to  right. 
Several  of  the  No.  2  knives  are  provided  only  with  one  angular 
cutting  surface.  By  this  means  only  a  very  thin  layer  of  cortical 
or  bark  tissue  is  removed  during  each  paring  operation,  the 
removed  substance  being  so  small  that  it  takes  quite  30  parings  to 
remove  one  inch  of  tissue.  This  is  a  most  important  point,  as  the 
bark  is  made  to  last  considerably  over  one  year  instead  of  only 
3  to  6  months.  This  knife  is  used  only  for  paring  off  the  lower 
edge  of  the  grooves  originally  made,  and  when  in  use  should  be 
held  so  as  not  to  make  the  cuts  deeper  than  the  previous  ones  ; 
this  is  effected  by  holding  the  knife  at  the  proper  angle.  Leaning 
the  knife  over  to  the  right  makes  the  cut  deeper,  while  leaning 
over  to  the  left  makes  it  less  deep.  The  knife  is  constructed  to 
prevent  the  cooly  cutting  deep  enough  to  touch  the  cambium. 
The  basal  cutting  surface  of  this  knife  has  now  been  made  much 
narrower,  the  change  effecting  a  greater  economy  as  less  material 
is  likely  to  be  removed  during  each  operation. 

No.  3  consists  of  a  spur-like  arrangement,  provided  with  a 
number  of  sharp  cutting  teeth.  It  is  used  to  cut  the  latex  tubes 
near  the  cambium  or  to  tap  the  latex  vessels  which  have  become 
unduly  distended  with  latex.  The  latest  patterns  are  provided 
with  one  or  two  pieces  of  metal,  the  solid  margins  of  which  prevent 
the  teeth  from  penetrating  too  deeply  ;  these  can  be  changed  in 
order  to  allow  the  teeth  to  penetrate  the  cortex  to  the  necessary 
depth — a  wise  provision  when  tapping  trees  of  widely  different 
ages.  It  can  be  used  alternately  with  No.  2  knife,  though  in  the 
Peradeniya  experiments  the  spur  knife  was  used  at  least  twice  as 
often  as  knife  No.  2.  It  was  by  the  use  of  these  knives  that  a 
yield  of  12  lb.  of  rubber  was  obtained  in  6  months  from  an  eleven- 
year-old  tree  in  the  south  of  Ceylon,  and  4  lb.  in  two  months  from 
each  of  four  trees  at  Peradeniya.  Despite  the  reputed  bad  effects 
of  pricking  it  is  only  fair  to  point  out  that  by  means  of  such  an 
implement  the  excised  area  in  three  months'  work,  tapping  twice 
per  week,  was  less  than  one  inch. 

A  New  Bowman-Northway  Knife. 

Another  knife  has  been  more  recently  invented  by  Messrs. 
Bowman  and  Northway,  and  has  been  fully  described  and  illus- 
trated in  the  "India-Rubber  Journal"  of  January  13th,  1908. 
The  cutting  part  is  shaped  like  the  letter  T.  The  cross  part  of  the 
cutter  has  its  extreme  points  turned  up  at  an  angle  and  sharpened 
at  both  ends.  Guide  pins  are  provided  to  regulate  the  depth 
of  the  cut  and  the  thickness  of  the  shaving,  and  also  to  sustain  the 
tool  with  the  blade  at  a  correct  angle.  The  implement  can  be 
used  either  on  the  right  or  left  hand  and  will  cut  either  backwards 
or  forwards. 


PARA     RUBBER  189 

Dixon's  Knife. 

This  consists  of  a  grooved  open  knife  blade,  capable  of  being 
adjusted  to  cut  the  bark  to  any  depth  or  at  any  angle.  The 
cutting  part  can  be  easily  removed  from  the  handle  of  the  knife, 
and  is  therefore  capable  of  being  replaced  when  worn  out.  The 
base  iS'  provided  with  a  pricker  for  determining  bark  thicknesses, 
removing  scrap  rubber  from  the  cuts,  making  holes  for  attaching 
tins,  &c.  It  can  be  used  for  making  the  original  groove  or  for 
paring  the  lower  surfaces  in  any  direction,  the  excision  being  made 
by  drawing  the  knife  towards  the  operator.  In  a  later  pattern 
the  cutting  blade  is  provided  with  sharp  margins,  two  blades, 
detachable  and  adjustable,  to  be  used  according  to  particular 
requirements. 

Macadam's   Comb    Pricker. 

Another  type  of  pricking  instrument  has  been  introduced  by 
Mr.  Macadam,  of  Culloden  estate,  Kalutara.  This  is  worthy  of  a 
detailed  description,  as  it  is  constructed  on  a  sound  principle  and 
is  different  from  any  other  pricking  instrument  known.  In  order  to 
distinguish  it  from  others  I  propose  to  name  it  a  "  Comb ' '  pricker. 
It  consists  essentially  of  a  flat  steel  blade  or  comb  provided  with  a 
dozen  sharp  teeth  on  one  side  ;  the  teeth  are  5  mm.  wide  and  9  mm. 
long  and  the  blade  is  11 J  cm.  in  length,  so  that  a  tapping  line  one 
foot  in  length  (30  J  cm.)  could  be  pricked  in  three  operations.  The 
blade  slides  along  two  side  grooves  and  is  provided  with  two  pro- 
jecting pieces  of  metal  for  handling  during  adjustment.  The  blade 
can  be  pushed  outwards  or  drawn  inwards,  thus  allowing  only  a 
definite  length  of  each  tooth  for  the  pricking  operation.  The  ease 
with  which  the  length  of  all  the  teeth  can  be  adjusted  is  a  great 
advantage,  as  a  cooly  going  from  tree  to  tree  can,  though  he  only 
possesses  one  piece  of  metal,  accurately  change  the  length  of  the 
teeth  according  to  the  thickness  of  the  bark  on  the  trees  being 
tapped. 

A  further  advantage  in  the  ' '  Comb ' '  pricker  is  that  the  latex 
tubes  are  incised  by  merely  pressing  the  line  of  teeth  against  the 
cortex.  Dragging  of  the  bark  cells  is  therefore  almost  impossible. 
In  other  prickers  the  tapper  naturally  draws  or  pushes  the  instru- 
ment in  a  particular  direction,  and  the  unavoidable  dragging 
may  result  in  a  clogging  of  individual  latex  tubes.  The  teeth  of 
the ' '  Comb ' '  are  very  easily  sharpened,  and  the  simple  and  effective 
apparatus  is  mounted  on  an  arched  handle  whereby  a  good  grip 
is  obtainable  and  the  required  pressure  conveniently  applied 
during  tapping  operations. 

The  Macadam-Miller  Paring  Knife. 

This  paring  knife  consists  of  two  detachable-  paring  surfaces 
connected  by  a  screw  roller.  The  cutting  parts  are  on  opposite 
sides  and  may  be  moved-  outwards  or  inwards  by  turning  the 
screw,  and  can  therefore  be  adjusted  according  to  the  depth  of 
the  bark  to  be  excised.  The  essential  parts  are  lodged  in  a  sub- 
stantial steel  head  firmly  attached  below  to  a  wooden  handle. 


igo  PARA     RUBBER 

The  knife  is  constructed  so  that  the  operator  may  cut  from  right 
to  left  or  left  to  right,  from  above  downwards  or  below  upwards. 
The  essential  parts  are  rather  difficult  to  get  at  and  may  prove 
troublesome  to  a  cooly  who  is  not  accustomed  to  adjusting  the 
paring  edges. 

Miller's  Knife. 

This  knife  was,  at  the  Ceylon  Rubber  Exhibition  of  igo6' 
classed  as  equal  with  the  Bowman-Northway  knives.  It  is  very 
simple,  and  consists  of  a  rectangular  or  box-shaped  piece  of  metal, 
open  at  both  ends,  and  provided  with  four  cutting  edges.  It 
can' be  used  for  excising  bark  from  right  to  left,  left  to  right, 
below  upwards,  and  above  downwards.  The  base  of  the  cutting 
surface  is  drawn  out  at  both  ends  to  form  a  fixed,  sloping  guard 
which  prevents  the  operator  from  cutting  too  deep.  It  is  simple, 
non-adjustable,  and  capable  of  paring  only  the  thinnest  strips  of 
bark. 

Sculfer's   Knife. 

A  cheap  and  durable  knife  has  been  brought  out  by  Mr.  H.  G. 
Sculfer.  The  knife  is  fitted  with  a  guide  which  allows  only  a 
small  paring  to  be  taken  off  at  each  cut,  also  stopping  any  danger 
of  cutting  the  cambium.  It  will  cut  either  right  or  left,  puUing  or 
pushing ;  it  is  easily  sharpened  and  there  is  no  possibihty  of 
the  knife  choking. 

"Barrydo"  Tapping  Knife. 

The  "Barrydo"  knife  comprises  a  blade  provided  with  four 
cutting  edges  ;  this  can  be  changed  rapidly  and  the  remaining 
sharp  edges  employed  in  whatever  direction  the  operator  is 
paring.  The  knife  cuts  right  and  left,  pull  or  push,  without  any 
adjustment  being  necessary.  It  has  been  recommended  by 
many  Ceylon  planters  and  has  been  used  on  several  Malayan 
estates. 

Pask-Holloway  Knife. 

In  this  knife  the  rectangular-shaped  piece  of  metal  at  the  end 
of  the  blade  is  almost  blocked  so  that  only  very  narrow  cutting 
edges  remain  for  excising  the  bark.  The  cutting  section  of  the 
metal  is  to  some  extent  adjustable,  and  is  attached  to  the  block 
by  means  of  a  bolt,  and  can  therefore  be  removed  and  easily 
replaced.  It  is  a  strongly-made  knife  and  can  be  used  both  for  the 
initial  and  subsequent  cuts.  The  double  cutting  edge  enables 
right  and  left-hand  cutting  to  be  done,  and  the  paring  can  be 
changed  from  medium  to  narrow. 

The    ' '  Secure  ' '    Knife. 

This  knife  will  cut  in  either  direction,  pulling  or  pushing,  and 
can  be  adjusted  according  to  the  thickness  of  the  bark  to  be 
tapped.  The  blade  is  joined  to  a  circular  disc  by  means  of  a  bolt, 
and  is  fitted  so  as  to  rotate  in  a  sUde  to  any  angle  required.     The 


L__- 


«  vk 

•       i 

'  'Yr' 


SCULFER'S      KNIFE.      BOWMAN     AND      NORTHWAY.  MILLER'S      KNIFE. 


TISDALL'S      KNIFE. 


DIXON'S      KNIFE. 


PARA     RUBBER 


191 


circular  base  and  disc  are  toothed  and  lock  securely  in  any  position. 
The  pin  has  a  square  shoulder  to  prevent  turning,  and  the  shank 
is  ri vetted  in  the  handle. 

Van  den  Kerckhove's  Knife. 

This  knife  consists  of  a  steel  spike,  with  handle.  At  the  end 
of  the  spike,  which  is  slightly  curved,  is  a  plate  with  a  screw  and 
three  movable  blades  with  oblique  edges.  These  blades  can  be 
regulated  according  to  the  thickness  of  the  bark  to  be  cut  ;  the 
blades  can  be  used  combined  or  singly,  according  to  requirements. 

Norzagaray's    Knife. 

At  the  end  of  this  tool  is  a  dome,  below  which  is  a  pair  of 
knives  formed  so  as  to  cut  two  slots,  preferably  inclined  one 
towards  the  other  at  their  lower  ends,  so  making  a  groove.  The 
knives  are  attached  to  a  spindle  passing  through  the  centre  of  the 
dome.  This  spindle  is  threaded  and  can  be  lowered  or  raised  to 
alter  the  depth  of  cuts.  The  knives  can  be  raised  out  of  the  bark 
by  means  of  a  lever  operated  from  the  handle.  They  are  driven 
into  the  bark  by  striking  with  a  mallet  the  end  of  the  spindle  where 
it  projects  above  the  dome.  In  a  simpler  form  of  the  instrument, 
the  knives  are  attached  to  the  cylindrical  end  of  the  tool  and 
through  this  end  passes  a  screw  with  a  foot-plate  at  the  base  for 
adjustipg  the  depth  of  the  cut.     This,  though,  is  very  complicated. 

Walker's  Combination  Knife. 

An  ingenious  knife,  brought  forward  by  Mr.  H.  E.  Walker,  is 
provided  with  paring  section  and  rotatory  pricker.  The  claims 
of  the  inventor  are  as  follows  :  (i)  the  combination  of  shaving 
blade  and  pricking  spur  allows  the  operator  to  use  either  (a)  blade 
and  spur  in  the  same  operation,  or  (b)  blade  or  spur  separately 
without  removing  any  part ;  (2)  by  pressing  the  guard  against  the 
trunk. it  acts  as  a  guide  and  causes  the  spur  to  prick  the  latex 
channels  in  the  innermost  layer  of  the  cortex,  but  prevents  the 
teeth  from  going  too  deep  ;  (3)  the  spur  may  be  easily  adjusted 
by  means  of  the  slot  in  which  it  is  fixed  and  may  be  made  to 
penetrate  to  varying  depths,  or  be  withdrawn  from  use,  without 
removal  of  any  part  of  the  instrument ;  (4)  the  form  of  the  spur  is 
such  that  during  use  it  will  prick  only  the  bark  on  which  it  is 
used  ;  (5)  the  guards  are  made  at  such  an  angle  with  the  blade  that 
the  excised  plane  will  always,  when  properly  used,  be  inclined 
towards  the  tree  and  thus  prevent  overflowing  ;  (6)  the  knife  can 
be  used  for  right  or  left-hand  tapping  without  any  adjusting. 

The   "Scorpion"   Paring   Knife. 

This  knife,  more  generally  known  as  Cameron  Brothers' 
"Scorpion"  Paring  Knife,  is  claimed  to  be  one  which  will  enable 
a  skilled  tapping  cooly  to  pare  300  lineal  feet  in  one  hour,  on  trees 
25  feet  apart  carrying  2  feet  of  tapping  line  each.     The  cutting 


192  PARA     RUBBER 

parts  have  been  designed  to  allow  the  operator  to  pare  thick  bark 
shavings   i-i8th  of  an  inch  in   thickness. 

Tisdall's    Knife. 

This  knife,  which  received  commendation  at  the  Ceylon 
Rubber  Exhibition,  consists  of  a  long  piece  of  metal  curved  at  the 
end  to  form  a  cutting  blade,  and  with  a  revolving  disc  attachment 
which  can  be  adjusted  to  regulate  the  depth  of  cut. 

Srinivasagam's  Knife. 

This  knife  is  designed  to  make  the  original  incisions,  to  pare 
off  thin  shavings,  to  channel  the  side  of  the  tapping  cut,  and  to 
clean  the  trees  or  remove  dead  bark.  The  boat-shaped  front 
prevents  the  cooly  from  cutting  too  deep,  the  clip  protector 
guards  the  cutting  edge,  and  the  openings  at  the  sides  allow  the 
bark  shavings  to  escape. 

The    Huber   Tapping    Knife. 

This  knife  has  been  designed  by  Dr.  Huber,  of  Para,  and 
stands  alone  in  the  nature  of  the  grip  provided.  In  general 
appearance  the  tool  resembles  a  tin-opener.  Behind  the  nose  is  an 
adjustable,  chisel-like  blade  projecting  backwards.  In  use,  the 
nose  rests  on  the  surface  of  the  tree,  serving  to  give  steadiness,  and 
at  the  other  end  of  the  handle  is  a  small  wheel  for  the  same  purpose. 

The    "  Burgess  "   Tapping    Knife. 

The  knife  is  ten  inches  long,  it  is  made  in  one  piece,  and 
there  is  nothing  to  adjust.  The  blade  of  the  knife  is  made  of  a 
small  flat  sheet  of  tool  steel  bent  into  gutter  or  ' '  pot-hook ' '  shape, 


the    '/burgess"    tapping  knife. 

resembUng  the  curved  blade  of  a  farrier's  knife.  This  is  joined  to 
a  metal  shaft,  which  is  carried  in  a  wooden  handle.  The  shaft 
has  double  curves,  which  are  specially  designed  for  preventing 
damage  to  the  tree  and  waste  of  bark  in  tapping. 

In  use  the  knife  is  held  with  the  shaft  and  broader  flat  side 
of  the  blade  applied  to  the  surface  of  the  tree,  and  the  shoulder  of 
the  bend  of  the  shaft  resting  on  the  groove  or  ledge  in  the  bark  of 
the  tree  made  by  previous  tapping.  The  cut  is  made  by  the 
cooly  pulling  the  knife  towards  himself. 

.  The  knife  is  said  to  be  equally  suitable  for  making  first  cuts  on 
a  tree  and  for  deepening  previous  cuts.  It  is  then  held  at  right 
angles  to  its  usual  position,  so  that  the  broad  flat  side  of  the  blade 
is  at  right  angles  or  inclined  to  the  surface  of  the  tree.     Owing  to 


PARA     RUBBER 


193 


the  curvature  of  the  trunk  of  the  tree  the  shoulder  on  the  shaft 
which  normally  limits  the  thickness  of  the  paring  is  then  ineffective, 
and  the  desired  depth  of  the  first  cut  can  be  rapidly  and  easily 
obtained. 

It  will  be  noted  that  the  pulling  force  exerted  by  the  cooly 
is  practically  in  direct  line  with  the  resistance  at  the  cutting  edge, 
and  there  is  therefore  no  tendency  for  the  knife  to  slip  or  rotate 
in  the  hand,  and  there  is  no  wrist  fatigue  in  using  it. 

The  curve  of  the  blade  is  designed  to  leave  a  clean  grooved 
channel  for  the  flow  of  the  latex,  and  there  is  no  tendency  for  the 
latex  to  overflow  the  groove  and  run  to  waste  down  the  tree  trunk. 

The  knife  is  sharpened  from  the  inside  of  the  bend  of  the 
blade.  This  is  easily  done  by  using  the  thin  rounded  edges  of 
wedge-shaped  stones  which  are  sent  out  with  the  knives.  The 
advantages  claimed  by  the  inventor  may  be  thus  briefly 
summarised  :  it  is  simple,  safe,  economical  of  bark,  no  other  tool 
is  wanted,  it  is  easy  to  learn,  easy  to  use,  easy  to  sharpen,  it  cuts 
a  grooved  channel,  and  is  cheap. 

Wynn-Timmins    Knife. 

This  is  a  knife  which  can  be  adjusted.  A  regular  and  uniform 
depth  of  cut  may  be  obtained  by  locking  the  knife  in  a  certain 
position,  while  at  the  same  time  it  can  be  regulated  to  give  a  greater 
or  smaller  cut  as  desired,  and  when  regulated  is  firmly  fastened  in 
place.  The  body  of  the  tool  is  provided  with  the  usual  slot  or 
recessed  portion  for  the  reception  of  the  knife,  which  is  engaged  by 
a  screw  pin  (LR.J.,  May  13th,  1911).  When  the  knife  has  been 
adjusted,  by  unscrewing  the  pin  or  key,  a  spring  forces  the  catch 
into  engagement  with  the  particular  notch  in  the  knife  and  thus 
locks  the  latter.  The  pin  or  key  can  then  be  withdrawn  from  the 
tool  body,  whereupon  the  knife  is  locked  until  the  pin  or  key  ia 
again  apphed. 

The  "Reaper"  Tapping  Knife. 

This  is  a  non-adjustable  knife  similar,  in  some  respects,  to 
others  already  on  the  market.  It  consists  entirely  of  steel,  the 
head  being  provided  with  four  cutting  edges  for  paring  in  both 
directions  by  pushing  or  pulling.  It  is  one  of  those  knives  which 
cannot  get  choked  by  bark  shavings.  It  is  simple,  and  is  made 
without  any  removable  screws,  bolts  or  nuts,  and  is  said  to  be 
capable  of  excising  parings  from  i-25th  to  i-2oth  of  an  inch  in 
thickness.  Compared  with  many  other  knives,  it  is  cheap  and 
durable. 


M 


CHAPTER     X. 

HOW    TO     TAP. 

Principles  to  be  Followed  in  Tapping. 

The  best  method  of  tapping  is  that  which  extracts  the  maxi- 
mum amount  of  latex  from  the  tree  with  removal  of  the  minimum 
quantity  of  cortical  tissue,  and  without  damaging  the  thin  layer  of 
cambium  cells.  The  cambium  is  responsible  for  the  renewal  of 
the  cortical  tissue  in  which  the  latex  tubes  arise  later  by  a  process 
of  perforation  and  decomposition  of  the  cells.  If  the  cambium 
is  damaged,  the  repairing  of  the  cortical  tissue  is  long  delayed,  and 
in  very  many  cases  the  areas  so  damaged  can  never  again  be 
tapped  to  the  same  advantage. 

Fitting  (p.  41,  Eng.  trans.)  thinks  that  the  above  statement  is 
not  complete,  and  suggests  that  the  following  addition,  at  least  in 
the  case  of  young  trees,  should  have  been  made  :  ' '  And  the 
best  method  of  tapping  is,  furthermore,  one  that  checks  the  trans- 
port of  organic  material  in  the  bark  towards  the  base  of  the 
tree  for  the  minimum  length  of  time,  with  the  minimum  degree 
of  intensity,  which  most  confines  this  interruption  to  a  local  area, 
and  which  .consequently  does  not  in  course  of  time  damage  the 
tree  or  injuriously  affect  the  renewal  of  bark  or  latex."  I 
cannot  refrain  from  stating  that  my  original  ' '  maxim ' '  covers 
many  of  the  points  in  Fitting's  addition,  and  the  latter  might  have 
been  framed  in  more  comprehensive  terms. 

At  Henaratgoda  and  on  estates  many  examples  of  the  effect  of 
injuring  the  cambium  may  be  seen  at  the  present  time,  though  the 
damage  may  have  been  done  many  years  ago.  The  surface  of  a 
badly-tapped  tree  does  not  become  even  and  smooth  for  many 
years,  and  tapping  on  the  best  system  on  such  trees  is  difficult 
and  often  impossible. 

Methods   of   Collectors  in    America. 

The  felling  of  wild  trees  and  the  ringing  of  the  bark  and 
cortex  in  order  to  collect  the  milk  are  now  only  practised  by  native 
collectors  upon  Castilloa.  The  latex  is  generally  collected  from 
Hevea  trees  while  they  are  still  standing.  An  upward  incision  is 
made  in  the  bark  by  means  of  a  small  axe,  and  a  cup  then  placed 
beneath  each  cut. 

Tapping  Methods  in  Africa. 
Funtumia  and  Ficus  trees,  and  also  hanes,  are,  in  Africa, 
usually   tapped   by   collectors   in    a   rudimentary    manner,    long 


]•  "■* 


Ze«^  by   India^Rubber  Journal 
A   NEW   PRICKING    METHOD   OF  TAPPING. 


-  ..1* 


Lent  ht/   Ivdin-Ruhher  Jovrjial. 
BASAL     TAPPING      IN      MALAYA. 


PARA     RUBBER  195 

incisions  being  the  general  rule.  There  are  few  Hevea  trees  in 
bearing,  but  where  these  exist,  as  in  Uganda,  the  Gold  Coast, 
and  Nigeria,  the  herring-bone  system  is  being  generally  adopted. 

Estate  Methods  of  Tapping. 
At  the  present  time  the  various  methods  of  tapping  Hevea 
trees  may  be  roughly  described  as  :  (a)  single  oblique  cuts  ;  (b) 
basal  V  or  Y  ;  (c)  multiple  V  incisions  ;  (d)  single  cuts  with  a 
vertical  channel  joining  them  (when  the  cuts  are  on  only  one 
side  of  the  vertical  channel,  the  system  is  termed  the  half-herring- 
bone, and  when  on  both  sides  the  full  herring-bone  system)  ;  (e) 
full  and  half-spiral  curves.  There  are  various  modifications,  but 
they  are  not  of  sufficient  importance  to  warrant  a  detailed  separate 
description. 

Single    Oblique    Cuts. 

It  should  be  explained  at  this  point  that  the  laticiferous  tubes 
from  which  latex  is  obtainable  in  large  quantities  are  mainly  dis- 
posed internally — very  near  the  cambium — and  for  the  most  part 
run  through  the  cortex  in  a  vertical  direction. 

It  should  also  be  remembered  that  the  latex,  even  when  most 
dilute,  is  apt  to  rapidly  coagulate  on  the  tree  and  to  form  scrap 
rubber.  A  cut  made  horizontally  will  not  conduct  the  latex  to  a 
central  point,  and  horizontal  tapping  is  invariably  accompanied 
by  a  large  proportion  of  scrap  owing  to  the  latex  trickling  down 
the  stem  and  drying  there.  A  vertical  channel  is  naturally  the 
best  for  conducting  the  latex  to  a  desired  point,  but  it  is  regarded  as 
extravagant  by  some  observers.  Parkin  proved  that  simple 
incisions  made  in  an  oblique  direction  gave  about  double 
the  yield  of  latex  as  either  the  vertical  or  horizontal,  the  latter 
two  showing  very  little  difference  in  yield  of  rubber.  Lecomte 
has  pointed  out  that  vertical  incisions  lay  open  very  few  latex 
tubes,  and  must  in  some  degree  have  the  effect  of  relieving  the 
tension  ;  one  may  therefore  expect  a  poorer  flow  of  latex  from 
such  incisions. 

Each  oblique  cut  may  be  from  one  to  six  or  more  inches  in 
length,  according  to  the  size  of  the  tree,  but  a  distance  of  nearly 
one  foot  apart  should  be  allowed.  They  slope  at  from  35°  to  45° 
towards  the  vertical.  The  oblique  incision  is  practically  the  basis 
of  most  other  methods  now  in  use,  and  is  spoken  of  as  the  half- 
spiral  system  when  the  incisions  are  of  considerable  length,  and  as 
the  herring-bone  when  connected  by  vertical  channels.  The 
distinction  between  the  half-spiral  and  the  half-herring-bone 
systems  is  that  separate  cups  must  be  fixed  to  each  cut  in  the  former, 
and  the  cuts  are  also  longer,  while  in  the  latter  the  cuts  are  joined 
by  a  vertical  channel  and  only  one  cup  is  required  at  the  base. 

Basal   V   or   Y. 

The  V  incision  is  nothing  more  or  less  than  a  double  oblique 
system.  The  sides  of  each  V  may  be  from  2  to  12  inches  in  length 
with  the  apex  of  the  V  at  the  lowest  point.     The  yield  obtainable 


196  PARA     RUBBER 

from  such  incisions  is  generally,  but  not  always,  about  double 
that  obtained  from  a  single  obhque  cut,  and  having  one  centre  for 
two  incisions  seems  to  be  one  of  the  greatest  advantages  of  this 
system. 

The  Y  is  merely  a  V  with  a  conducting  channel. 

The  system  of  tapping  by  means  of  a  basal  V  or  Y  is  generally 
limited  to  the  first  tapping  period  of  a  tree.  The  base  of  the  tree 
trunk  is  somewhat  bottle-shaped  and  possesses  bark  of  considerable 
thickness  compared  with  that  three  to  five  feet  from  the  base. 
Comparatively  large  yields  have  been  obtained  from  four-year-old 
Hevea  trees  in  Malaya  by  these  methods.  Subsequently,  as  the 
tree  increases  in  girth,  tapping  lines  are  added  and  the  system  of 
half-herring-bone  tapping  instituted. 

Recent  investigations  suggest  that  the  basal  V  may  not  be  as 
beneficial  as  two  basal  single  oblique  cuts  on  opposite  sides  of  the  tree. 
Until  this  point  has  been  definitely  proved  it  may  be  wiser  to  adopt 
the  latter  system,  as  it  would  allow  the  cooly  to  tap  areas  separated 
from  each  other  with  the  maximum  amount  of  bark,  and  only  one 
side  need  be  tapped  on  separate  occasions.  The  basal  system  of 
tapping  is  generally  believed  to  give  a  better  yield  of  rubber  per 
area  of  bark  excised  and  a  reduced  quantity  of  scrap  than  certain 
other  systems  ;  but  if  it  is  carried  out  on  young  trees,  and  in  any 
way  affects  the  growth  of  the  plants  at  that  age,  I  advise  planters 
to  abandon  it. 

It  has  been  suggested  that  the  reason  why  the  quantity  of  latex 
obtainable  is  not  double  that  from  a  single  oblique  cut  is  because 
the  cuts  are  very  close  to  one  another  and  may  draw  on  the  same 
system  of  laticiferous  tubes,  a  conclusion  which  is  warranted  by  the 
results  of  many  experiments  in  various  parts  of  Ceylon.  In 
addition  to  this  drawback  there  is  also  another  serious  result  which 
often  accompanies  this  method  of  tapping,  viz.,  the  loosening  of  the 
bark  on  drying  and  tapping  from  the  apex  of  the  V  upwards. 

Multiple   V   Incisions. 

The  V's  are  usually  made  on  the  stem  from  the  base  up  to  a 
height  of  six  feet,  and  are  distanced  about  six  inches  apart.  The 
open  end  of  the  V  is  usually  about  six  inches  wide.  There  is, 
however,  a  great  variation  in  the  size  of  the  cuts,  the  smallest 
incisions  measuring  about  one  inch  in  length. 

It  cannot  be  doubted  that  in  a  system  of  small  obhque  or  V 
cuts  a  considerable  amount  of  labour  is  involved  in  fixing  and 
adjusting  a  very  large  number  of  collecting  tins  at  the  base  of  each 
incision,  and  though  this  system  cannot  be  regarded  as  drastic  and 
harmful  to  the  tree,  it  is  likely  to  be  superseded  by  others  when 
planters  have  to  find  labour  sufficient  to  regularly  tap"  large  acreages 
of  mature  rubber.  In  the  oblique  or  V  incisions  a  chisel  or  paring 
knife  is  commonly  used,  though  most  of  the  implements  previously 
described  may  be  tried  in  these  systems. 


PARA     RUBBER 

Limitations  of  the  V  System. 


197 


In  the  V  method  it  has  been  noticed  that  when  the  sides  of 
four  adjacent  V  cuts  are  drawing  on  an  area  of  60  to  80  square 
inches,  the  flow  of  latex  after  two  months'  tapping  becomes  very 
poor.  This  method  obviously  cannot  be  carried  out  for  the 
same  length  of  time  as  the  half  or  full-spiral  curves,  because  the 
oblique  cuts  sooner  or  later  interfere  with  one  another  and  draw  on 
the  same  limited  area.  Four  trees,  tapped  similarly  by  the  use  of  a 
paring  knife  and  the  spur,  gave  10  lb.  14!  oz.  of  dry  rubber  from 
the  29th  June  to  the  6th  September,  1905. 

Some  experts  in  Java  believe  that  a  very  high  yield  of  rubber 
per  unit  of  bark  excised  is  obtained  by  the  V  method. 

In  some  countries  the  exudations  from  trees  are  obtained  by 
making  incisions  in  the  form  of  inverted  V's,  but  such  a  method  has 
no  great  advantage  in  connection  with  the  tapping  of  Hevea 
rubber  trees.  Srinivasagam  (Ceylon  Observer,  Sept.  22nd, 
1910),  claims  that  this  system  is  being  vindicated  by  recent 
workers. 

Yield  from  V  Tapping  in  Ceylon. 

The  following  are  the  details  of  the  trees  at  Peradeniya,  which 
were  tapped  on  the  V  system.  The  letter  P  indicates  the 
days  on  which  the  pricker  was  used. 

It  will  be  noticed  that  the  quantity  of  latex  obtained  by  the 
use  of  Bowman  and  Northway's  pricker  was  usually  much 
greater  than  that  obtained  by  the  paring  knife  ;  this  was  to  some 
extent  due  to  the  fact  that  the  innermost  laticiferous  tubes  near 
the  cambium  were  penetrated  by  the  points  of  the  pricker. 

It  is,  however,  an  open  question  whether  the  total  yield  from  a 
series  of  pricking  and  paring  operations  is  in  excess  of  that  obtained 
by  the  same  number  of  parings,  if  a  long  enough  interval  of  time  is 
allowed  to  elapse.  The  large  yield  resulting  from  the  use  of  the 
pricker  was  followed  by  a  poor  flow  after  paring. 


Four  Peradeniya  Trees — 29  Years  Old 
Yield  of  Rubber  from  V  Cuts. 


Weight. 

Weight. 

Date. 

lb. 

oz. 

Date.                                      lb.    02. 

29-6-05 

4 

Brought  forward                ..      6     15 

1-7-05 

3l 

31-7-05 

7i 

5-7-05 

"1 

2-8-05 

7 

7-7-05 

loi 

3-8-05 

5 

10-7-05 

14 

4-8-05 

3 

12-7-05 

I2i 

5-8-05 

3: 

14-7-05 

6:: 

7-8-05 

4: 

17-7-05 

9j 

9-8-05 

2  : 

19-7-05 

8- 

10-8-05 

i| 

21-7-05 

9: 

1 1-8-05 

If 

24-7-05 

7i 

I 2-8-05 

If 

26-7-05 

7 

P     15-8-05 

3 

28-7-05 

7 

17-8-05 

li 

Carried  forward 

..     6 

15 

Carried  forward 

9     n| 

198 


PARA     RUBBER 


Brought  forward 
P     18-8-05 

19-8-05 
P    21-8-05 

22-8-05 
P    23-8-05 

24-8-05 
P    25-8-05 

26-8-05 
P    28-8-05 

29-8-05 

P    30-8-05 

P    31-8-05 

1-9-05 


Carried  forward 


Weight. 

lb.  oz. 

9  II J 

Brought  forward 

if 

P 

2-9-05 

2i 

4-9-05   ■ 

2i 

P 

5-9-05 

0';- 

6-9-05 

If 

P 

7-9-05 

oi 

8-9-05 

If 

P 

9-9-05 

If 

1 1-9-05 

I 

P 

12-9-05 

0*. 

P 

13-9-05 

If 

15-9-05 

I 

P 

18-9-05 

°i 

10  iij 

Weight. 

lb.  oz. 

10  ili 
li 
of 
If 
oi 
14 
of 
li 
oi 
I 

oi 
of 

If 


5l 


At  the  end  of  the  tapping  operations  the  hnes  of  adjacent 
V's  were  beginning  to  interfere  with  one  another,  and  the  trees 
were  therefore  rested.  The  average  yield  in  the  first  five  weeks 
was  two  pounds  of  rubber  per  tree,  but  subsequently  the  yield 
fell  off  considerably. 

Vernet's    Results. 

Vernet  (Bull.  Econ.  de  I'lndochine,  No.  44)  gives  an  account 
of  experiments  in  V  tapping.  From  100  open  V's,  by  re-opening 
both  edges,  1,153  cc.  of  latex  were  obtained  ;  by  re-opening  the 
lower  edge  a  yield  of  872  cc.  of  latex  was  secured.  It  might 
appear  that  had  the  lower  edge  been  opened  twice,  a  yield  of 
1744  cc.  (872  by  2)  would  have  been  obtained,  thus  showing  a 
better  result  from  the  lower  edge. 


Herring-Bone  System. 

This  consists  of  a  series  of  short,  parallel,  oblique  incisions  con- 
nected with  a  vertical  one.  The  incisions  may  be  on  one  or  both 
sides  of  the  vertical  channel,  and  vary  in  length  from  about  4  to 
12  inches.  The  vertical  channel  may  vary  from  i  to  6  feet  in 
length,  and  is  usually  sufficiently  wide  to  conduct  the  late.x  from  a 
dozen  oblique  cuts.  The  cup  placed  at  the  base  is  the  only 
receptacle  for  the  latex.  The  advantage  of  this  system  hes  in  the 
minimum  labour  required  for  collecting  operations,  but  there  are 
many  reasonable  objections  against  the  waste  of  tissue  which 
occurs  when  a  vertical  channel  of  considerable  depth  and  width 
is  made.  Though  it  is  considered  to  be  more  drastic  than  the 
foregoing  methods,  this  system  is  in  use  on  most  estates  in  Ceylon, 
and  has  been  adopted  with  success  by  planters  and  officials  in  the 
Malay  Peninsula,  India,  and  Africa.  It  appears  to  receive  more 
favour  than  any  other  system  of  tapping  known  at  the  present 
time. 

After  the  original  oblique  incisions  have  been  made,  they  are 
re-opened  by  paring  away  the  lower  surface,  this  operation  being 


PARA    RUBBER  199 

continued  until  the  whole  of  the  tissue  between  the  lines  is  used  up. 
Any  of  the  knives  described  may  be  used  for  these  operations. 

'  When  the  herring-bone  system  is  used,  there  is  no  necessity  to 
fix  spouts  at  the  base  of  each  incision,  as  the  latex  flows  down  the 
vertical  channel  in  the  bark.  Experiments  have  been  made  with 
conducting  channels  composed  of  clay,  the  inner  ridge  being  left 
open  at  the  base  of  the  incision  and  the  outer  one  continuous 
from  top  to  bottom  in  the  half-herring-bone  system,  and  both 
ridges  open  at  the  base  of  the  incisions  when  the  full  herring-bone 
system  is  adopted.  Such  a  channel  is  easily  made,  it  lasts  for 
quite  a  long  time,  and  in  so  far  that  it  does  away  with  the  vertical 
cut  in  the  bark  is  to  be  recommended  experimentally. 

According  to  Eraser  (T.A.,  July,  1910),  the  full  herring-bone 
system,  three  months  on  one  side  and  three  months  on  the  other, 
is  considered  wasteful  in  Malaya,  as  every  change  means  three 
cuts  wasted  before  a  normal  flow  begins. 

Zig-Zag  Tapping. 

The  zig-zag  system  of  tapping  consists  of  a  series  of  irregularly 
arranged  oblique  cuts  of  varying  length,  joined  together  by  sloping 
conducting  channels,  and  so  arranged  that  the  latex  is  collected 
at  the  base  of  the  lowest  incision  in  the  series.  This  system  is 
about  the  only  one  that  can  be  recommended  for  trees  which, 
on  account  of  previous  bad  tapping,  have  become  gnarled  and 
woody  on  the  surface  ;  the  downward  and  oblique  lines  can  be 
made  of  any  length  and  at  any  angle,  and  the  knots  thereby 
avoided. 

NORTHWAY    AND    BoWMAN'S    SpIEAL    CURVES. 

Another  method  which,  on  account  of  the  good  yields  obtained, 
attracted  considerable  attention  in  Ceylon  and  elsewhere  is 
the  long  spiral  curve.  The  system  consists  of  a  series  of  parallel 
cuts  running  round  the  stem  and  each  ending  separately  at  the 
base  of  the  tree  ;  or  of  shorter  cuts  ending  at  convenient  places. 
The  number  of  spiral  cuts  is  determined  by  the  circumference 
of  the  tree,  there  being  usually  one  curve  for  every  12  to  18 
inches  of  girth  at  the  top  of  the  tapping  area.  In  this  method 
of  tapping  a  series  of  special  knives  was  used  ;  these  ensured  the 
minimum  waste  of  tissue  when  re-opening  the  lower  side  of  the 
wound.  As  this  system  gave  an  average  of  2  lb.  per  tree  for  each 
month's  tapping  at  Peradeniya,  and  was  continued  in  some  districts 
until  a  total  of  16  lb.  per  tree  was  obtained  in  twelve  months, 
it  was  viewed  favourably  for  a  time. 

When  Spiral  Tajpping  can  be  used. 

It  cannot  be  doubted  that  the  full-spiral  system  is  drastic, 
and  though  excellent  yields  were  once  obtained  by  its  adoption,  it 
has  been  realized  that  cortical  stripping  should  not  be  effected 
too  rapidly  even  on  old  trees.  It  is  a  good  system  to  adopt  when 
it  is  intended  to  kill  out  intermediate  trees  on  estates  which 
are  too  densely  planted,  and  can  in  such  instance's  be  carried  out  on 


200  PARA    RUBBER 

young  trees.  The  results  obtained  by  this  system  on  io-to-30- 
year  old  trees  at  Henaratgoda  and  Peradeniya  appeared  at  one 
time  to  justify  its  adoption  on  old  Hevea  trees,  providing  the 
operation  was  carried  out  carefully  and  slowly.  The  bark  on  the 
old  trees  at  the  places  mentioned  was  removed  at  the  rate  of  only 
one  inch  in  three  months. 

Despite  the  numerous  advantages  of  this  system  of  tapping 
there  are  so  many  disadvantages,  especially  if  it  is  practised  on 
young  trees,  that  it  has  fallen  into  disuse  except  for  trees  which 
have  to  be  killed  and  ultimately  uprooted. 

Yields  from  Spiral  Tapping  in  Ceylon. 

Four  trees,  29  years  old,  were  tapped  65  times,  and  yielded 
a  total  crop  of  27  lb.  3  bz. 

The  results  which  have  been  obtained  from  the  full-spiral 
system  at  Peradeniya  are  not  as  satisfactory  as  those  at  Henarat- 
goda, and  are  only  briefly  indicated  here.  At  Peradeniya  four 
trees,  then  nearly  30  years  old,  were  tapped  from  June,  1905.  to 
February,  1906,  at  irregular  intervals.  About  three-quarters  of 
the  bark  tissues  were  removed  from  the  base  to  a  height  of  five 
to  six  feet  by  alternately  pricking  and  paring  the  lower  surface. 
Altogether  each  tree  was  tapped  on  150  occasions  during  the  time 
specified,  and  the  yield  obtained  was  approximately  6f,  lb.  of 
dry  rubber  per  tree. 

At  Henaratgoda  25  trees,  from  15  to  20  years  old,  were 
tapped  approximately  twice  per  week  from  September  26th,  1905, 
to  February,  1906.  The  pricker  was  used  alternately  with  the 
paring  knife,  and  in  an  interval  of  4J  months  the  width  of  bark 
tissues  removed  along  each  line  was  only  il  to  2  inches.  The 
results  show  that  by  tapping  on  37  occasions  a  total  of  50I  lb.  of 
dry  rubber  was  obtained. 

Pi  The  following  shows  some  of  the  yields  obtained  by  tapping 
on  the  full-spiral  system  at  Henaratgoda.  Each  tree  was  tapped 
from  the  base  to  a  height  of  5  or  6  feet  during  a  period  of  about 
4I  months  : — 

Number  of  Number  of  Yield  of 

times  tapped.  Trees.  Rubber. 

lb. 


37 

112 

56 

18 

100 


25 
5 
5 
5 
5 


50. 


301* 
261V 

27ii! 

According  to  Joseph  Eraser  (T.  A.,  July,  1910)  in  Malaya  the  full 
and  half-spiral  and  also  the  full  herring-bone  systems  are  being 
abandoned  in  favour  of  the  half-berring-bone  system. 

New  Tapping  Systems  in  Ceylon. 

It  is  not  long  since  a  system  of  pricking  the  trees,  and  washing 

the  latex  down  previously  cleaned  stems  by  means  of  water 

ejected  ;from  syringes,  was  favourably  reported  on  by  officials 

and  planters  in  Ceylon.     The  system  was  not  made  public,  but 


Fhnto  by   D.   L.  Gunawardane. 
HALF-SPIRAL       TAPPING. 


V.:<ln  hii  D.  L.  (i II luiifardane 
FULL      SPIRAL     TAPPING      OF      RENEWED      BARK. 


PARA     RUBBER  201 

was  specially  recommended  for  young  trees,  and  was  said  to 
be  remarkable  for  the  economy  of  bark  effected  by  its  adoption. 
Ihis  system  will  be  criticised  later  in  the  present  chapter. 

A  Vertical  System  for  Young  Trees. 

Another  system  was  advertised  at  the  recent  Rubber  Exhibi- 
tion in  London  (I.R.J.,  July  ist,  1911).  A  tree,  originally  planted 
by  me  at  Gangaruwa,  was  shown.  It  was  4-J  years  old,  and  was 
tapped  70  days,  the  yield  being  i  lb.  3  oz.  An  acre  of  similar 
trees  was  tapped,  and  an  average  yield  of  i  lb.  3  oz.  per  tree  ob- 
tained. 

In  this  new  system  of  tapping  the  minimum  amount  of  cortex 
is  rernoved.  Commencing  at  a  height  of  6  ft.,  two  channels  are 
cut  right  to  the  ground.  A  tapping-knife  having  four  or  five 
blades,  each  about  an  inch  apart,  is  placed  vertically  on  the  trees 
and  hit  with  a  small  hammer.  The  latex  flows  down  the  channels 
and  is  collected  at  the  bottom.  The  next  day  other  channels  are 
made  an  inch  to  the  right  on  both  sides,  and  so  on  until  they  have 
gone  completely  round  the  tree.  The  system  could  be  described 
as  tapping  on  alternate  days  by  incision,  and  only  vertically. 
The  objeqt  of  tapping  vertically  is  not  to  interfere  with  the 
•circulation  of  the  sap.  At  the  end  of  the  70  days  the  trees  which 
have  been  experimented  upon  showed  no  sign  of  injury,  according 
to  the  inventor.  It  was  claimed  that  a  cooly  could  tap  one 
hundred  trees  per  day  by  this  sj^stem.  The  system  must,  however, 
be  regarded  only  as  experimental. 

Comparisons  of  Yields  by  Different  Systems  of  Tapping. 

The  objects  of  my  experiments  at  Henaratgoda  were  numerous. 
One  of  them  was  concerned  with  the  yield  of  dry  rubber  obtainable 
by  different  systems  of  tapping,  and  is  of  particular  interest  to 
those  persons  having  rubber  trees  in  bearing.  A  plantation  of 
75  rubber  trees,  15  to  20  years  old,  was  selected  for  the  experiments, 
and  25  trees  in  each  of  three  groups  were  marked  out  and  tapped 
on  the  (a)  full-spiral,  (b)  half-spiral,  and  (c)  the  full  herring-bone 
systems.  Tapping  was  commenced  on  the  26th  September,  1905, 
and  continued  until  the  13th  of  February,  1906,  the  latter  being 
the  period  when  most  of  the  trees  were  undergoing  their  change  of 
leaf. 

It  was  impossible  to  obtain  exact  equality  in  all  the  physical 
conditions,  and  it  is  beyond  the  power  of  any  one  to  calculate  the 
individual  potentialities  of  the  selected  trees  ;  nevertheless,  the 
following  details  will  serve  to  indicate  the  results  which  may  be 
obtained  from  such  trees  under  conditions  similar  to  those  pre- 
vaihng  at  the  time  of  the  experiments. 

Full  Spiral.       Half -Spiral.        Full  herring- 
bone. 

Area  excised,  in  square  inches       12,414!         ..      5,003^  ..       7,348^ 

Number  of  times  tapped        .  .  37  . .  41  .  .  39 

Yield  of  dry  rubber,  in  lb.      .  .  50J        . .  35  J  .  .  47  ,V 

Yield  of  dry  rubber  per  5,000 

square  inches,  in  lb.        ..  2o'49     ..  34'47  ••  32'55 

Yield   of  dry  rubber  per  40 

tappings  from   25   trees, 

in  lb 550       ..  3420  ..  4852 


202  PARA    RUBBER 

Spiral  and  Herring-Bone  Tapping  Compared. 

It  is  probably  unwise  to  draw  final  conclusions  from  the  above 
experiments,  as  the  period  occupied  by  the  whole  of  the  work  was 
only  about  five  months  and  the  trees  were  15  to  20  years  old  at 
the  time  of  the  experiment.  But  care  was  exercised  to  equalize, 
as  far  as  possible,  the  physical  conditions  in  the  three  sections  and 
to  avoid  erroneous  deductions  being  made.  A  synoptical  state- 
ment of  the  significance  of  the  above  table  is  here  given. 

In  the  first  case  it  is  obvious  that  the  full-spiral  system 
necessitates  the  stripping  of  the  cortex  or  bark  at  the  quickest  rate, 
and  the  half-spiral  at  the  minimum  rate. 

The  largest  yield  per  group  of  25  trees  was  obtained  from  the 
full-spiral  system,  the  next  best  from  the  full  herring-bone,  and  the 
poorest  yield  from  the  half-spiral  system  of  tapping.  This  is  only 
what  may  be  expected  when  one  realizes  that  the  bark  removed  in 
the  full-spiral,  full  herring-bone,  and  half-spiral  systems  was  in 
the  ratio  of  12  :  7  :  5,  respectively.  It  seems  reasonable  to  con- 
clude that  since  the  above  results  show  that  the  maximum  quantity 
of  rubber  per  tree  has  been  obtained  from  the  full-spiral  system, 
such  a  system  might  be  recommended  where  it  is  expedient 
that  the  rubber  should  be  placed  on  the  market  as  quickly  as 
possible  irrespective  of  the  effect  on  the  trees.  By  adopting  this 
system  the  maximum  quantity  of  bark  is  removed  in  a  given 
time,  and  it  is,  therefore,  the  best  one  to  follow  in  thinning-out 
estates  which  are  too  closely  planted.  It  is  extremely  doubtful 
whether  this  system  should  be  adopted  on  trees  intended  to 
permanently  occupy  the  land  ;  the  effect  on  the  trees  is  bad. 

On  the  other  hand,  it  appears  that  the  maximum  quantity 
of  rubber  for  equal  areas  of  bark  has  been  obtained  from  the  half- 
spiral  system,  and,  therefore,  that  this  system  is  not  only  the 
least  harmful,  but  is  the  most  economical,  and  is  one  which,  on  a 
permanent  estate,  will  give  the  best  yield  from  the  available 
tapping  area. 

It  should,  however,  be  pointed  out  that  in  these  experiments 
the  different  systems  have  been  followed  in  such  a  manner  that  the 
paring  operations  have  only  removed  from  i^  to  2^  inohes  of 
cortex  along  each  incision  in  five  months.  The  tapping  lines  were 
originally  12  inches  apart,  so  that  the  whole  of  the  area  prepared 
for  tapping  will  only  be  worked  through  once  in  about  two  to  three 
years. 

Half-Herring-Bone  and  Basal  Y  Systems  Compared. 
Upon  the  Sapong  estate,  British  North  Borneo,  some  observa- 
tions have  been  made  upon  the  merits  of  these  two  systems.  The 
trees  were  tapped  for  twelve  months,  and  were  5  to  6^  years  old. 
It  was  determined  that  there  is  practically  no  difference  in  yield 
per  tree  by  either  method  of  tapping,  but  the  "half-herring-bone" 
system  required  the  excision  of  189  square  inches  of  cortex  for 
each  pound  of  dry  rubber  obtained,  whereas  the  "  Y  "  system  only 
required  the  excision  of  147  square  inches  to  obtain  the  same 
amount. 


PARA     RUBBER  203 

Half-Herring-Bone  and  V  Systems  in  Java. 

The  Buitenzorg  experiments  indicated  in  1908  the  highest 
yield  of  rubber  per  unit  of  bark  excised  from  the  half-herring- 
bone system  as  against  the  full  herring-bone  and  spiral  systems. 
Dr.  Tromp  de  Haas  appeared  inclined  to  think  that  the  short  V 
cut  would  be  still  better.  It  certainly  would  give  a  higher  yield 
per  square  metre  of  bark  than  any  other  system,  because  there 
is  so  little  bark  cut  away.  I  cannot,  however,  regard  the  V 
method  as  being  systematic.  The  lines  of  adjacent  V's  draw  on 
the  same  area  after  a  very  short  time.  They  prevent  regular 
paring  from  above  downwards  throughout  the  length  of  the 
trunk  ;  and  the  apex  of  each  V  is  apt  to  turn  up  in  dry  weather.  I 
should  not  be  surprised  to  see  some  planters  giving  the  system 
another  trial.  Such  a  development  would  be  a  very  natural 
reaction  after  the  drastic  methods  adopted  on  some  estates. 

Estate  Considerations  in  Tapping. 

Having  briefly  described  the  various  systems  of  tapping 
in  the  Middle-East  and  the  results  obtained,  it  is  now  necessary 
to  consider  other  points  which  require  attention,  no  matter  what 
system  of  tapping  is  adopted.  Incision  and  pricking  as  against 
paring,  the  distance  between  tapping  lines,  thickness  of  bark 
shavings,  cooly  tapping  tasks,  and  the  systems  of  tapping  accord- 
ing to  girth  and  bark-renewal,  are  all  of  paramount  importance 
to  estate  managers. 

Excision    versus    Incision    in    Brazil. 

From  observations  made  in  the  Amazonas,  Norzagaray 
(Lectures  on  Indiarubber,  page  155)  contends  that  incision  is  to  be 
recommended  for  the  following  reasons  :  (i)  the  same  incision 
produces  always  the  same  quantity  and  quality  of  latex,  irrespec- 
tive of  direction  of  cut  or  its  position  in  sunlight  or  shade  ;  (2) 
the  quantity  of  latex  obtained  increases  up  to  a  certain  extent  in 
proportion  to  the  number  of  previous  incisions  ;  (3)  300  incisions 
of  only  one  inch  in  length  yield  from  5  to  12  lb.  of  dry  rubber  per 
tree  during,  approximately,  150  days  in  the  year.  His  objections 
to  the  paring  or  excision  method  are  :  (i)  the  unnatural 
process  of  removing  the  living  bark  impairs  the  nutritive  functions 
of  the  tree,  exiposing  it  to  the  injurious  effects  of  atmospheric 
influences  and  to  the  attacks  of  certain  insects  ;  (2)  the  excision 
of  the  living  bark  introduces  a  considerable  quantity  of  chemical 
and  mechanical  impurities ;  (3)  an  appreciable  percentage  of 
scrap  rubber  is  produced  ;  (4)  not  one  of  the  many  present-day 
inventions  completely  meets  the  requirements  of  this  system,  and 
professional  skill  or  the  discovery  of  a  special  implement  is 
necessary.  He  also  points  out  that  though  the  collector-  in  the 
Amazon  is  hampered  in  his  work  by  natural  obstacles,  he  uses  the 
incision  system  only,  by  which  he  makes  about  300  incisions  on 
each  tree  every  year.  Yet  he  admits  that  the  system  adopted  by 
native  collectors  ultimately  destroys  the  trees,  a  large  quantity  of 


204  PARA     RUBBER 

sap  is  liberated  which  mixes  with  the  latex,  and  there  is  con- 
siderable loss  of  latex.  The  rough  method  of  incision  as  practised 
in  Brazil  has,  in  a  measure,  been  tried  on  a  Ceylon  plantation,  and 
from  the  disastrous  results  obtained  no  one  could  ever  recommend 
its  adoption  by  planters. 

The  faults  of  the  system,  can,  however,  be  partly  eliminated  by 
careful  incision  without  damaging  the  cambium. 

Wickham  still  adheres  to  the  principle  of  clean  sharp  incision 
instead  of  the  paring  method  adopted  in  the  East.  He  contends 
that  the  pubhshed  estate  returns  do  not  show  an  appreciable 
increase  in  yield  over  that  obtained  by  making  clean  incisions 
which  entail  the  minimum  strain  on  the  trees.  This  appears  to  be 
rather  a  bold  statement  to  make. 

It  is  now  generally  admitted  that  while  there  is  every  reason 
why  the  bark  should  be  preserved  for  as  long  as  possible,  the 
incision  method  adopted  by  native  collectors  in  Brazil  is  accom- 
panied by  so  many  serious  disadvantages,  arising  mainly  from 
wounding  of  the  cambium,  as  to  render  its  adoption  on  Eastern 
estates  undesirable. 

Pricking  and  Paring  Methods. 

Incision  by  native  collectors  leads  us  to  the  consideration  of 
incision  by  pricking  implements.  It  is  obvious  that  in  the  various 
systems  it  is  possible  to  use  either  paring  or  pricking  knives 
alone  or  these  instruments  alternately.  A  recent  system  of  prick- 
ing only,  invented  by  a  Ceylon  planter,  and  reported  favourably 
upon  by  Willis  (T.A.,  Feb.,  1909),  Eraser,  and  Clements,  was  said 
to  be  simple  and  less  costly  than  the  usual  paring  methods,  and  to 
give  quicker  and  possibly  increased  returns.  It  was  condemned 
(T.A.,  June  1909),  because  it  tapped  the  whole  circumference  of 
the  tree  at  one  time  and  appeared  likely  to  induce  undesirable 
growths.  The  incisions  were  said  to  close  up  prematurely,  the 
latex  then  flowing  between  the  cambium  and  bark  and  there 
forming  pads.  On  the  other  hand,  some  authorities  claim  that 
much  of  the  damage  was  due  to  bad  work  on  the  part  of  the 
tappers,  and  that  the  system  in  its  original  or  improved  state  was 
worthy  of  a  longer  and  more  scientific  test. 

Pricking  is  now  rarely  adopted  on  Hevea  trees,  except  alter- 
nately with  paring.  Even  the  latter  system  is  being  discarded, 
mainly  on  account  of  the  very  thin  bark  shavings  which  are  now 
cut  by  ordinary  paring  knives  and  also  for  other  reasons.  The 
effects  of  pricking  will  be  dealt  -with  in  a  later  chapter. 

General  Principles  in  Systems  of  Tapping. 

It  is  now  necessary  to  detail  a  few  of  the  important  principles 
underlying  tapping  operations,  such  as  direction  of  cuts,  distance 
of  tapping  Unes,  thickness  of  bark  shavings,  tapping  tasks,  etc. 
I  cannot  do  better  than  preface  these  with  four  axioms  laid  down 
by  Francis  Pears,  of  Lanadron  (Souvenir,  India-Rubber  Journal): — 

(i)  That  touching  wood  is  a  sign  of  bad  tapping,  yet  the 
reverse  is  not  necessarily  a  sign  of  good  tapping. 


PARA     RUBBER 


205 


(2)  That  it  is  not  advisable  to  let  latex  come  in  contact  with 
anything  but  glazed  surfaces,  such  as  glass,  enamelled  ware,  or 
glazed  pottery. 

(3)  That  in  tapping  it  is  most  important  to  have  organization 
and  a  system  whereby  there  are  fewest  loop-holes  for  coolies  to  do 
what  they  should  not. 

(4)  That  a  good  average  tapper  is  capable  of  cutting  1,200  feet 
of  bark  as  a  daily  task. 

Direction    of    Cuts. 

Most  up-to-date  tapping  knives  allow  the  tapper  to  cut 
right  to  left  and  left  to  right.  This  is  essential  where  the  full 
herring-bone  system  is  in  vogue,  and  is,  according  to  some  observers, 
desirable  on  account  of  the  yield  obtainable  by  tapping  with  the 
cuts  in  a  certain  direction.  It  is  stated  (T.A.,  Aug.,  1910) 
that  in  25  stems  examined,  the  fibres  sloped  slightly  up  to  the 
light  in  18,  in  the  other  7  they  were  practically  vertical.  It  was, 
therefore,  argued  that  a  cut  sloping  down  to  the  right  would  cut 
more  latex  tubes  than  one  sloping  to  the  left. 

A  series  of  experiments  was  made  (T.A.,  Oct.  and  Dec,  1910), 
on  trees  at  Peradeniya,  some  being  tapped  with  the  cuts  sloping 
from  right  to  left  and  others  from  left  to  right,  both  on  the  half- 
spiral  system.  After  computation  to  equalise  the  numbers  of 
trees  and  of  tappings,  the  comparative  yields  may  be  given  as 
follows  : — 

Right  to  left    ..  ..        14,904  grammes  of  dry  rubber. 

Left  to  right    . .  .  .        12,774 

Any  advantage  in  girth  lay  with  the  trees  cut  from  left  to  right. 
The  presumption  is  that  cuts  sloping  from  right  to  left  yield 
better  than  those  sloping  left  to  right.  The  difference  is  so  small, 
and  the  period  of  the  experiments  so  short,  that  any  deductions 
therefrom  are,  in  my  opinion,  extremely  dangerous.  There  is 
eve]:y  probability  of  parts  of  even  the  same  tree  showing  consider- 
able variation,  and  experiments  should  be  made  on  a  very  large 
number  of  trees  for  a  long  period  of  time  before  advice  is  given. 

Upper  and  Lower  Sides  of  Cuts. 

It  is  customary  in  paring  to  excise  the  bark  only  on  the  lower 
surface.  Some  authorities  have  suggested  that  the  upper  surface 
as  well  as  the  lower  should  be  re-opened.  This  is  dangerous, 
especially  if  bad  tapping  is  frequently  done,  as  much  of  the  healing 
which  normally  takes  place  from  above  downwards  (as  well  as 
from  within  outwards)  is  prevented.  Dr.  Tromp  de  Haas  tapped 
four  trees  at  Tjikeumeu,  and  obtained  the  following  yields  : — 

Incised'  on  Incised  on 

lower  edge  only.  both  edges. 

(i)  380  grammes  552  grammes 

(2)  180     „  370 

(3)  23/    „  403 

(4)  221     ,,  300 

1,018     ,,  1,625 


2o6  PARA    RUBBER 

A  higher  yield  is  naturally  to  be  expected  by  tapping  two 
surfaces  instead  of  one,  but  to  be  justifiable  the  yield  must  be 
mainta'ined  for  a  long  period  and  be  in  proportion  to  the  quantity 
of  bark  excised.  In  the  above  experiments  the  jdeld  from  the  double 
incision  was  far  less  than  double  that  from  the  single  incision. 
Another  series  of  experiments  gave  per  square  metre  of  tapped  area : 
incision  on  lower  edge  only,  390  grs.  ;  on  both  edges,  414  grs., 
thus  proving  the  advisability  of  tapping  the  lower  edge  only. 

With  some  bearing  upon  this  point  is  an  experiment  made 
by  Vernet  (Journ.  d'Agric.  Tropicale,  Jan.  1910),  who  ringed  a 
tree,  and  with  circular  cuts  tapped  the  upper  and  lower  sides 
of  the  ring.  In  17  days  77  c.cm.  of  latex  were  got  from  the 
upper  and  156  c.cm.  from  the  lower  edges.  Two  factors  were 
suggested  by  \'ernet.  First,  there  is  a  difference  in  tension  of 
the  tissues,  because  the  lower  part  is  in  communication  with  the 
water-absorbing  roots,  while  the  upper  part  is  in  communication 
with  the  water-losing  leaves.  Second,  the  flow  from  the  upper 
part  stops  sooner  owing  to  greater  readiness  on  the  part  of  the 
rubber  to  coagulate,  a  fact  proven  by  another  experiment  of  his 
own. 

Supervision  of  Tapping. 

Much  of  the  success  or  failure  in  tapping  can  be  attributed 
to  the  care  with  which  the  tapping  lines  are  laid  out.  It  is 
necessary  to  have  all  tapping  lines  parallel  and  at  definite  distances 
in  order  to  check  subsequent  work.  On  most  estates  separate 
batches  of  coolies  are  reserved  for  laying  out  tapping  lines  and 
making  the  first  cuts.  When  the  latter  work  is  being  executed 
the  cooly  should  make  two  or  three  clean  strokes  rather  than 
rub  the  tapping  knife  over  the  newly-made  cut. 

When  tapping  has  been  commenced,  Murdoch  advises  (I.R.J., 
June  13th,  1910)  keeping  a  daily  return  of  yields  and  dividing 
the  force  into  groups,  a  separate  record  for  each  being  kept. 
A  group  showing  a  sudden  rise  or  fall  can  at  once  be  visited. .  He 
would  not  recommend  more  than  6,000  trees  in  a  section,  each 
group  of  cooUes  being  controlled  by  a  good  cooly  or  sub-kangani. 
He  claims  that  it  is  impossible  for  the  European  staff  to  watch 
all  the  labour.  '  Parkinson  reported  that  on  his  estate  they  worked 
by  fields  of  20  acres  or  more. 

Parallel  and  Irregular  Paring. 
It  is  a  very  common  sight  on  some  estates  to  see  the  bark 
between  the  original  parallel  tapping  hues  of  varying  width  after 
tapping  has  been  going  on  for  several  months.  This  is  due  to 
the  tendency  of  the  cooly  to  cut  away  at  every  tapping  operation 
more  bark  near  the  end  of  the  tapp'ing  line  where  it  meets  the 
vertical  conducting  channel  than  in  the  upper  part.  Towards 
the  end  of  the  tapping  period,  strips  of  bark  are  left  which  are 
not  continuous  with  the  vertical  conducting  channel.  Very  often 
this  bark  cannot  be  tapped,  and  is  allowed  to  peel  away.  This 
represents  so  much  bark,  and  therefore  rubber,  lost  to  the  planter, 


PARA    RUBBER 


207 


•and  though  every  care  is  taken  to  prevent  this  on  well-managed 
■estates,  it  is  frequently  observed  on  some  properties. 

Number  of  Trees  Tapped  per  Cooly. 

The  number  of  trees  tapped  per  cooly  per  day  varies  enor- 
mously and  is  particularly  small  in  fields  tapped  for  the  first  time 
or  when  the  trees  are  very  large.  Furthermore,  the  number  and 
length  of  tapping  lines  per  tree,  and  the  bad  or  good  condition 
of  renewed  bark,  greatly  affect  the  number  of  trees  which  can 
be  tapped,  per  cooly,  in  an  ordinary  day.  In  some  accounts  the 
tapping  task  includes  not  only  making  the  cuts  but  fixing  collecting 
cups  and  collecting  scrap  from  the  tapped  trees  each  day.  The 
maximum  number  of  cuts  made  per  cooly  per  day  is  reported  as 
1,600  ;  there,  however,  the  coolies  did  not  collect  the  scrap.  On 
Malayan  estates  from  800  to  1,500  cuts  per  day,  or  250  to  310 
trees  per  day,  seems  to  cover  most  tasks. 

Parkinson  states  (I.R.J.,  June  13th,  1910)  that  the  task 
must  vary  with  the  age  of  the  tree.  He  gave  an  average  of  150 
trees  with  8  cuts  each,  making  a  total  of  1,200  cuts,  the  cooly 
collecting  the  latex  and  bark,  washing  the  cups,  and  carrying 
the  latex  to  the  coagulating  sheds.  With  older  trees  he  gave  an 
average  of  120  trees  with  8  cuts  each.  The  ' '  scrapping ' '  was  done 
by  women  and  children.  When  doing  150  trees  the  cooly  did 
75  in  the  morning,  stopped  collecting  the  latex,  then  another 
75,  finishing  at  from  2  to  2.30  p.m. 

Number   of   Tapping   Cuts   per   Inch. 

The  number  of  cuts  per  inch  is  often  an  index  of  the  amount 
of  supervision  given  to  the  tapping  coolies.  The  larger  the  number 
of  cuts  per  inch,  the  less  detrimental  will  be  the  effect  of  tapping  on 
the  tree,  and  the  larger  the  yield  of  rubber  per  unit  of  excised  bark, 
presuming,  of  course,  that  the  parings  are  always  sufficiently  thick 
to  permit  of  an  issue  of  latex.  The  various  tapping  knives  now 
on  the  market  vie  with  one  another  in  their  ability,  when  skilfully 
used,  of  cutting  away  bark  of  the  minimum  thickness.  The  actual 
thickness  of  the  bark  on  young  and  old  trees,  and  its  texture,  is 
said  to  determine  to  some  extent  the  minimum  thickness  of  each 
paring. 

Malcolm  Gumming  states  that,  in  tapping  ten-year-old  trees 
for  the  first  time,  only  10  to  12  cuts  per  inch  can  be  made.  Parkin- 
son affirms  that  it  is  not  possible  to  get  so  many  cuts  on  renewed 
bark  as  on  trees  newly  tapped.  It  is  said,  nevertheless,  by  Gallagher, 
"that  more  cuts  to  the  inch  can  be  made  on  the  soft  bark  of  young 
trees  than  on  the  hard  bark  of  older  trees  tapped  for  the  first  time. 

The  thickness  of  the  parings  varies  by  about  100  per  cent., 
the  minimum  being  i-30th  of  an  inch,  and  the  maximum  about 
i-i6th  of  an  inch  ;    the  former  is  reported  in  the  F.M.S.  and  the 


2o8  PARA    RUBBER 

latter  in  Ceylon.  Experience  has  shown  that  a  better  5dield  is 
obtained  with  20  cuts  than  with  15  to  the  inch.  Anything  less  than 
20  cuts  to  the  inch  denotes,  according  to  Gallagher,  faulty  manage- 
ment ;  23  is  considered  as  average,  and  25  and  over  as  very  good. 
This  does  not  include  the  first  incision,  the  width  of  which  varies 
according  to  the  knife  and  the  amount  of  skill  used. 


Distance  between  Tapping  Lines. 

Where  tapping  is  done  on  the  four-year-system  on  four  sides 
of  the  tree,  it  is  often  convenient  to  have  the  tapping  lines  twelve 
inches  apart  in  order  that,  at  the  rate  of  one  inch  per  month,  each 
section  can  be  made  to  last  one  year.  If  each  side  is  tapped 
on  alternate  days  throughout  the  whole  year,  and  the  average 
thickness  of  bark  excised  at  each  tapping  is  about  i-i5th  of  an 
inch,  the  system  is  almost  ideal.  In  parts  of  Malaya,  however, 
the  strip  of  bark  removed  in  each  operation  is  usually  much 
thinner  than  i-i5th  of  an  inch,  varying  generally  from  i-2oth  to 
i-30th  of  an  inch.  Furthermore,  during  certain  months  work 
cannot  proceed  regularly,  on  account  of  holidays,  bad  weather, 
etc.  ;  this  affects  the  average  total  width  of  bark  excised  each 
month.  It  is  therefore  necessary  for  each  planter  to  adopt  a 
distance  between  tapping  lines  according  to  the  general  system  upon 
which  he  is  working  the  estate.  If  he  is  tapping  one  quarter- 
section  only  for  each  of  four  years  on  alternate  days,  working  25 
days  in  the  month,  and  his  bark  shavings  are  I-I5th  of  an  inch 
thick,  the  tapping  lines  should  be  10  inches  apart  to  last  one  year. 
If  the  thickness  of  the  bark  removed  is  i-20th  or  i-30th  of  an  inch, 
the  distance  should  be  about  7^  or  5  inches  apart  respectively,  a 
spacing  which  is  obviously  too  close.  If  daily  tapping  is  adopted, 
then  the  distance  should  be  doubled.  It  is  generally  better  to 
make  the  tapping  lines  too  far  apart  than  too  close  together. 

If  the  system  adopted  is  the  two  opposite  quarters  to  last 
two  years,  and  the  opposite  sides  are  tapped  on  alternate  days 
(each  tree  being  tapped  each  day,  but  on  opposite  sides),  then  the 
distances  of  the  tapping  hues  should,  if  the  shavings  are  i-i5th, 
i-20th,  or  i-25th  of  an  inch  in  thickness,  be  20,  15,  and  12  inches 
apart  respectively.  It  is  therefore  seen  that,  allowing:  (i)  for  only  an 
average  of  25  working  days  per  month,  (2)  bark  shavings  i-25th 
of  an  inch  thick,  and  (3)  alternate  day  tapping,  using  two  opposite 
quarters  to  last  two  years,  the  original  distance  of  12  inches 
between  tapping  hnes  suggested  by  me  still  stands  good.  The 
distance  must,  of  course,  be  increased  if  the  working  days  per 
month  or  the  thickness  of  the  bark  daily  excised  are  increased  be- 
yond those  specified.  If  the  number  of  tapping  days  for  the 
planned  period  is  divided  by  the  thickness  of  the  bark  shavings, 
the  quotient  is  the  distance  to  be  allowed  between  the  tapping 
lines.  The  following  table  will  perhaps  prove  useful  to  planters 
planning  out  their  tapping  operations  : — ■ 


PARA     RUBBER  20Q 

Distance  between  tapping  lines 
Average  thickness         For  Daily  For  Tapping 

in  inches  of  Tapping 

bark  shavings.  to  last. 

I  Year.      2  Years. 


24  Working  Days  each  Month. 

A 

28* 

57i 

1 

T5 

191 

38f 

a'cr 

14I 

28t 

A 

11*;- 

23A 

j'd 

91 

i9i 

25   Working 

Days 

EACH   Month. 

t\t 

30 

60 

t'^ 

20 

40 

A 

15 

30 

-A 

12 

24 

jV 

10 

20 

26  Working  Days  each  Month. 


TO- 

3it 

02f 

A 

20i 

4IJ 

rzV 

151 

31* 

A 

"il 

2414 

jV 

IO| 

20* 

27  Working  Days 

EACH  Month. 

T^ 

321 

644 

1 

1  0 

2lf 

43* 

A 

16^ 

32f 

A 

i2ii- 

25fl 

^n 

lot 

214 

28  Working  Days  each  Month. 

t'o  331             67i 

t's  22|             44* 

A  16*             33i 

2^  1325  2D2^ 

^  II*  22f 

29  Working  Days  each  Month. 

T5  34*  69I 

tV  23*  46* 

sV  17*  341 

25  -^325  */23 

fV  "f  23* 

30  Working  Days  each  Month. 

A  36  72 

T5  24  48 

A  x8  36 

A  14*  28* 

s\s  12  24 

Tapping  Systems  and  Other  Considerations. 
A  visit  to  the  East  will  convince  everyone  that  there  is^great 
diversity  of  opinion  and  methods  among  planters  of  repute. 
This  applies  not  only  to  methods  of  planting,  but  to  systems  of 
tapping,  kinds  of  tapping  knives  used,  and  curing  apparatus. 
The  following  summary  of  the  methods  on  three  estates  in  Ceylon 
will  serve  to  illustrate  this  point  : — 


on  altera 

ate 

days. 

I  Year.     2 

Years. 

ins. 

ins. 

14* 

28* 

9J 

19* 

7* 

14* 

5*1 

iiH 

4* 

91 

15 

30 

10 

20 

7i 

15 

6 

12 

5 

10 

15I 

31* 

loi 

20* 

7* 

15* 

6ft 

i2.;f 

5* 

lof 

16* 

321 

10* 

2lf 

H, 

I6.i 

m 

12  J* 

5l 

10* 

i6| 

33# 

II* 

22| 

8* 

16* 

m 

13a 

5f 

II* 

17* 

34* 

"S 

23* 

8t'o 

i7f 

6|* 

i3« 

5* 

II* 

18 

36 

12 

24 

9 

18 

7* 

I4f 

6 

12 

210  PARA     RUBBER 

Estate  Cu.  Estate  Gk.  Estate  De. 

Tapping  system    ..  Half-herring-bone.  Full  herring-bone.   Spiral. 
Knives  used  . .  Miller's.  Michie-Golledge.      Bowman  &  North- 

way. 
Curing  systems      . .  Vacuum  driers.         Chambers  main-     Tea-withering 

tained  at  85°  F.  shed. 

Form  of  rubber     .  .  Cr^pe.  Worms.  Sheet. 

It  is  obvious  from  the  above  that  the  systems  adopted  on 
these  three  estates  are  as  different  as  they  can  possibly  be.  Never- 
theless, at  most  exhibitions  the  produce  from  all  of  these  estates  is 
generally  well  thought  of. 

A  still  more  striking  example  is  furnished  by  Bryce,  of  Tebrau 
Estate,  Johore  (Souvenir,  India-Rubber  Journal)  who  brings 
forward  the  arguments  of  two  managers  of  two  of  the  largest 
rubber-producing  estates  in  Malaya. 

For  convenience  Bryce  refers  to  them  as  A  and  B. 

A's  argument  is  as  follows  : — 

"  The  present  price  of  rubber  is  approximately  5s.  6d.  per 
lb.,  and  there  is  no  reason  to  think  that  the  price  of  rubber  will 
ever  be  much  higher  than  this.  The  area  now  being  tapped  on 
the  estates  in  his  charge  is  only  a  fraction  of  the  total  planted  area. 
His  object,  therefore,  is  to  get  as  much  rubber  as  possible  from  these 
trees  without  unduly  injuring  them.  Later  on  it  is  possible  that 
he  may  have  to  give  them  a  year's  rest  to  allow  time  for  bark 
renewal,  but  by  then  he  will  have  a  very  much  larger  area  in 
bearing.  It  is  true  that  his  cost  of  production  is  higher  than  B's 
cost  of  production,  but  that  is  because  his  method  of  tapping  is 
necessarily  more  laborious,  and  the  extra  amount  of  latex  obtained 
is  not  in  proportion  to  the  amount  of  extra  work  involved,  yet  at  the 
existing  price  of  rubber  his  profit  is  much  greater  than  B's  profit, 
since  he  is  getting  double  the  amount  of  latex  per  tree.  Further- 
more, owing  to  large  dividends,  his  company's  shares  are  at  a 
high  premium,  whicl>  enables  them  to  issue  new  shares  at  about 
this  premium,  and  purchase  other  estates  partly  in  bearing  at  a 
very  low  cost  to  original  shareholders." 

Now  follows  B's  argument. 

"  His  object  is  to  get  the  cost  of  production  as  low  as  possible, 
and  to  tap  lightly  to  ensure  always  having  sufficient  bark  area. 
He  has  chosen,  therefore,  the  simplest  and  hghtest  method  of 
tapping,  which  enables  his  coohes  to  tap  the  maximum  number 
of  trees  (800  per  coolie  per  day)  and  which  necessitates  cutting 
the  minimum  amount  of  bark.  The  tapping  is  all  done  on  con- 
tract, and  the  tappers  divided  into  three  classes  according  to 
their  skill,  with  heavy  fines  for  too  deep  cutting. 

"  Furthermore,  his  tappers  are  not,  as  on  most  estates,  allowed 
to  place  the  cups  and  collect  the  latex,  but  are  confined  to  tapping 
only,  since,  as  he  rightly  states,  tappers  are  skilled  labour,  and 
collecting  the  latex  can  be  done  by  women  and  children  at  a  much 
cheaper  rate. 


PARA     RUBBER  211 

"  In  this  way  he  has  reduced  the  cost  of  production  to  a  very 
low  figure,  and  is  sure  of  having  sufficient  b#k  area  to  continue 
tapping  indefinitely. ' ' 

The  above  examples  show  how,  from  financial  and  other 
considerations,  the  views  of  planters  may  be  influenced.  In  this 
volume  the  views  I  express  on  tapping  are  mainly  based  on  the 
principle  that  the  best  methods  of  tapping  are  those  that  are  sound 
from  a  hygienic  point  of  view.  The  future  health  and  yielding- 
capacity  of  the  trees  are  regarded  as  the  most  desirable  features 
to  strive  for,  rather  than  large  and  quick  returns  and  diseased 
or  weak  trees. 

General  Estate  Systems  of  Tapping. 

Whatever  system  of  tapping  is  adopted,  I  think  it  is 
essential  that  the  same  areas  should  be  regularly  tapped,  and  not 
one  side  or  part  of  it  allowed  to  rest  for  one  or  more  months  and 
then  be  re-tapped.  Where  tapping  every  alternate  day  is  carried 
out  the  cooly  removes  a  very  thin  piece  of  bark,  and  gets  a  reason- 
able flow  of  latex.  If  tapping  is  commenced  on  a  given  area  after 
one,  two  or  more  months'  rest,  the  first  few  tappings  give  very 
little  latex,  a  quantity  of  bark  and  also  valuable  labour  being 
thereby  wasted.  Of  course,  where  the  tree,  through  some  cause  or 
other,  does  not  yield  latex  in  proper  quantity  or  of  the  required 
quality,  a  rest  must  be  given.  Such  a  procedure  is,  fortunately, 
not  often  necessary. 

Three-Year  System. 

The  main  factor  underlying  modern  tapping  operations 
is  the  interval  of  time  allowed  for  secondary  bark  to  mature 
before  being  re-tapped.  In  some  countries  three  years  are  allowed, 
but  in  most  a  four-year  interval  is  regarded  as  much  safer.  When 
the  three-year  system  is  adopted,  the  tree  is  marked  out  into  thirds, 
and  one  part  is  tapped  each  year.  This  is  a  system  which  has 
been  approved  by  some  directors  and  planters  in  Malaya. 
Adherents  to  this  system  generally  believe  in  tapping  every  day,  and 
in  having  the  tapping  lines  nine  inches  apart,  trees  16  inches  in 
girth  having  two,  trees  18  inches  having  four,  and  trees  20  inches 
as  many  as  six  cuts  on  each  tapping  area.  Many  prefer  this 
system  because  the  tapping  lines  on  young  trees  can  then  be  made 
longer  than  in  the  quarter-section  system.  It  appears  to  be 
gaining  favour  among  Ceylon  planters. 

Four-Year  System. 

In  May,  1908,  my  system  of  tapping  was  drawn  up  for, 
and  adopted  by,  a  large  estate  in  Province  Wellesley  : — 

1.  The    tapping   lines    should   be    about    12    inches    apart, 

and  sloping  at  an  angle  of  approximately  45  degrees. 

2.  The  half-herring-bone   system,  or,   in  the  case  of  smaller 

trees,  basal  Y  or  V  to  be  adopted. 

3.  Tapping  to  be    done    on   each  side  every  alternate  day 

(each  tree  being,  therefore,  tapped  daily). 


212  PARA     RUBBER 

4.  The   renewed  bark    to   be    four   years   old   before   being 
tapped.    « 

(A)  Trees  15  to  18  inches  girth. 

Tap  the  basal  foot  only  on  half  the  tree.  This  should  be 
done  only  where  the  trees  have  a  vigorous  appearance,  and  are 
ove    three  years  old. 

(B)  Trees  18  to  20  inches  girth. 

Divide  the  tappable  section  into  north,  south,  east,  and 
west.  Tap  to  a  height  of  3  feet  on  the  half-herring-bone  system 
on  two  opposite  quarter-sections,  these  two  quarter-sections  to 
last  two  years. 

(C)  Trees  20  to  24  inches  girth. 

Tap  up  to  only  4  feet  in  the  same  manner  as  B. 

When  the  trees  are  above  24  inches,  the  tapping  area  should 
be  raised  to  5  feet,  the  same  system,  i.e.,  four  quarter-sections, 
being  adopted.  The  girths  referred  to  above  are  those  at  a  yard 
from  the  ground.  As  each  tree  increases  in  girth  and  passes  from 
one  class  to  the  other,  additional  tapping  hnes  are  added.  On 
some  estates  where  the  tapping  hnes  are  18  inches  apart,  and 
the  trees  are  tapped  daily,  trees  with  a  girth  of  15  inches  may  have 
one  cut,  and  18-inch  trees  two  cuts. 

This  system,  if  properly  carried  out,  will  not  unduly  tax 
the  trees.  It  will  give  a  gradual  increase  in  yield  from  the 
beginning,  and  will  permit  of  an  interval  of  at  least  four  years  for 
the  renewed  Lark  to  mature. 

This  quarter-section  system  has  since  been  adopted  by 
some  planters  in  Selangor,  and  on  estates  with  which  I  have  some 
connection  in  Sumatra,  Borneo  and  Java,  and  has  been  approved 
by  independent  experts  in  Malaya. 

Fitting,  at  a  later  date,  advised  that  the  tapping  system 
to  be  recommended  was  the  division  of  the  bark  into  four  quarter- 
sections,  on  the  half-herring-bone  system,  each  to  be  tapped  for 
one  year,  the  whole  of  the  bark  to  last  four  years.  He  states 
that  Ridley  confirms  the  adoption  of  the  system. 

Several  planters  have  objected  to  this  system  because  they 
consider  that  four  years  is  too  long  a  period  to  allow  for  renewed 
bark  to  form  and  mature.  My  own  view  is,  that  if  any  change 
in  the  bark-renewal  period  is  made  it  should  be  to  lengthen  the 
time,  rather  than  to  shorten  it,  for  each  cycle  of  renewed  bark.  It 
is  surely  a  great  enough  strain  on  the  trees  to  renew  the  bark  four 
times  in  the  first  twenty  years, 

Gallagher  favours  the  quarter-section  system  of  tapping 
(half-herring  bone),  as  he  beheves  bark  renewal  and  flow  of  latex 
will  be  better  from  this  than  from  any  other  system  in  vogue.  He 
prefers  tapping  one  quarter  for  one  year  only,  instead  of  two 
opposite  quarters  for  two  years.  The  following  is  the  system  he 
outHned  from  the  beginning  of  tapping  : — On  young  trees,  measur- 
ing 18  to  20  inches  at  a  yard  from  the  ground,  put  on  a  basal  V  18 
inches  high,  and  tap  every  day.  This  will  last  one  year.  The 
second  year,  put  a  similar  V  on  the  other  side.     The  third  year 


PARA    RUBBER  213 

begin  the  one-quarter-in-one-year  system  on  either  of  the  first 
two  quarters  tapped,  and  put  on  cuts  as  high%s  the  girth  allows, 
taking  the  opposite  quarter  the  fourth  year.  His  reasons  for 
departing  from  the  one-quarter-in-one-year  system  for  the  young 
trees  are  :  (i)  In  trees  5  to  6  years  old  which  have  had  only  one 
cut  upon  them  the  renewed  bark  in  two  years  is  thick  enough 
to  be  tapped  ;  (2)  the  cuts  are  short,  and  the  distance  which 
building  material  must  move  transversely  is  not  so  great  as  in 
later  years  ;  (3)  the  cut  on  one  quarter  is  too  short,  and  the  bark 
is  too  thin  higher  up. 

NORTHWAY  AND   BOWMAN'S  SySTEM  OF  MARKING  THE  TrEES. 

The  system  consists  first  in  marking  out  the  grooves  at  the 
correct  distance  and  angle  at  which  they  are  to  be  cut  during 
tapping.  This  is  effected  by  means  of  a  guide  in  the  shape  of  a 
right-angled  triangular  piece  of  tin,  the  side  subtending  the  right 
angle  being  2  ft.  in  length,  and  the  other  sides  17"  by  17".  The 
hypotenuse  is  the  line  along  which  the  trees  are  marked,  one  of 
the  17"  sides  being  arranged  vertically  before  marking  is 
commenced. 

The  grooves  to  be  cut  along  the  sloping  side  or  hypotenuse  of 
the  triangle  wiU  then  be  at  an  angle  of  45  degrees  to  the  base, 
each  groove  2  ft.  long  and  at  intervals  of  one  foot,  starting  one  foot 
from  the  base  of  the  tree,  up  to  a  height  of  5  ft.,  and  all  leading 
into  a  vertical  channel  running  down  to  within  a  few  inches  from 
the  ground  level.  A  small  tin  spout  is  inserted  at  the  lower  end 
of  the  vertical  channel  to  convey  the  latex  into  the  tin  vessels, 
which  are  placed  on  the  ground  near  the  tree.  The  tin  spout  is 
left  in  position  permanently,  thus  obviating  the  necessity  of  con- 
stantly inserting  cups  into  the  bark  and  removing  them,  and  at 
the  same  time  avoiding  injury  to  the  tree.  In  the  case  of  a  tree  18" 
in  circumference,  the  grooves  would  go  nearly  once  round,  and 
therefore  for  trees  of  this  size  there  would  be  one  vertical  channel  to 
convey  the  latex  flowing  from  the  several  spiral  cuts  into  the  tin 
receptacle,  and  only  one  of  the  latter  would  be  needed.  A  tree  36' 
in  circumference  would  require  2  vertical  chanriels  on  opposite 
sides  of  it,  and  correspondingly  a  tree  54"  in  circumference  would 
take  3  vertical  channels,  each  leading  into  a  tin  receptacle  placed 
on  the  ground  as  previously  stated.  To  suit  trees  of  various  sizes 
and  yielding  capacities,  the  grooves  can  be  made  longer  or  shorter  as 
may  be  found  necessary  or  convenient. 

Holloway's  System  of  Marking. 

Mr.  Francis  HoUoway  has  also  given  me  particulars  of  his 
method  of  marking  the  trees.  A  long  rod,  marked  off  into  feet,  is 
placed  against  each  tree.  A  sheet  of  zinc  or  tin,  cut  at  a  certain 
angle  (about  45°),  fits  at  one  end  into  the  rod,  and  can  be  moved  up 
and  down  as  desired.  The  remaining  part  of  the  zinc  or  tin  ribbon 
is  then  wound  round  the  tree  and  the  markings  made.  The  rod, 
being  marked  into  distances  of  one  foot,  can  be  used  at  any  height 


214  PARA    RUBBER 

on  the  trunk,  the  spaces  between  the  oblique  tapping  markings 
being  in  every  case  parallel  and  distanced  one  foot  from  each  other. 
This  plan  can  be  adopted  for  marking  out  spiral  curves  or  oblique 
incisions,  and  is  therefore  applicable  to  the  herring-bone  system. 

The  Collecting  of  Latex. 

Having  indicated  the  general  principles  concerning  tapping 
implements  and  operations,  it  now  remains  for  us  to  consider  the 
more  special  contrivances  and  methods  adopted  in  the  process  of 
collecting  latex. 

A  Protector. 

Mr.  A.  H.  Bury,  Ceylon,  has  devised  an  apparatus  to  protect 
the  collecting  cups  from  rain  and  mechanical  impurities  during 
tapping  operations.  "The  protector  is  to  consist  of  a  zinc  coUar 
round  the  trunk  of  a  rubber  tree,  sloping  slightly  downwards  at 
an  angle  approaching  45  degrees.  The  protector  will  have  a  centre 
edging  of  felt,  fitting  on  the  tree  so  as  to  catch  any  moisture  running 
down  it  and  allow  it  to  drain  off  the  roof  over  the  latex  cup.  It  will 
also  fasten  with  a  stud  fastening,  in  the  same  way  as  an  ordinary 
collar,  only  there  will  be  several  holes  on  the  one  end  of  the  collar 
that  fastens  over  the  other,  so  as  to  allow  of  the  same  sized  coUar 
being  attached  at  various  times  to  trees  of  different  girth. ' '  This 
does  not  appear  to  have  been  adopted  by  many  planters. 

Centralizing  the  Latex  from  many  Trees. 

On  all  estates  each  tree  is  separately  visited  for  the  collection 
of  the  latex,  an  arrangement  which  requires  a  very  large  labour 
force  when  large  acreages  are  in  bearing.  Where  the  trees 
are  regularly  planted  and  the  slope  of  the  ground  is  favourable,  it 
has  been  suggested  that  an  arrangement  for  collecting  the  latex 
from  all  or  a  large  number  of  the  trees  should  be  adopted. 

A  method  has  been  brought  forward  having  for  its  object 
the  collecting  of  the  latex  from  an  indefinite  number  of  incisions 
in  one  or  more  trees  and  conveying  it  to  a  common  centre.  Its 
complete  success  depends  upon  keeping  the  latex  in  a  liquid 
condition  for  a  period  of  time  varying  according  to  the  distance 
over  which  the  latex  has  to  be  transmitted.  The  method,  though 
ingenious,  is  not  considered  practical. 

Drip-tins  :  their  Construction  axd  Action. 
It  is  well  known  to  most  planters  who  are  tapping  Hevea 
rubber  trees  that  the  latex  as  it  issues  from  a  newly-made  incision 
may  vary  much  in  consistency,  sometimes  being  very  watery  and 
flowing  freely,  at  other  times  being  too  thick  to  trickle  along  the 
hnes  prepared  for  it.  In  high  tapping  the  latex  may  have  to 
traverse  a  distance  of  over  twenty  feet  along  the  stem  before  it 
reaches  the  receptacle  at  the  base,  and  in  many  instances  never 
succeeds  in  being  collected  except  as  scrap  rubber.  Furthermore, 
the  latex  during  periods  of  drought  does  not  run  so  freely  as  when 
the  moisture  conditions  are  more  favourable. 


PARA     RUBBER  215 

In  all  such  instances  the  latex  tends  to  coagulate  on  the  tree 
and  is  subsequently  collected  as  scrap.  An  attempt  has  been  made 
to  overcome  this  difficulty  by  the  use  of  a  receptacle  called  the 
drip-tin.  This  consists  of  a  tin  vessel  made  to  hold  a  known 
quantity  of  water  or  water  containing  ammonia  or  formalin.  It 
has  a  concave  surface  to  fit  the  convex  outline  of  the  tree  and  is 
fixed  to  the  bark  by  means  of  pins.  At  the  base  it  is  drawn  out 
to  a  fine  point,  which,  when  the  drip-tin  is  adjusted,  is  in  contact 
with  the  tapping  area  on  the  stem.  The  point  is  provided  with 
an  ingenious  screw  arrangement  by  means  of  which  the  drop  of 
liquid  allowed  to  issue  can  be  regulated  according  to  requirements. 
The  apparatus  is  placed  at  the  top  of  each  incision,  and  as  soon  as 
the  tree  has  been  tapped  the  drip  is  allowed  to  commence.  By  these 
means  the  latex  is  to  a  great  extent  prevented  from  drying  up  on 
the  stem  and  is  carried  rapidly  towards  the  base  ;  the  latex  tubes, 
not  being  blocked  by  the  coagulated  substances,  continue  to  give 
forth  latex  for  a  long  period.  It  is  claimed  that  this  invention 
will  greatly  reduce  the  amount  of  scrap,  and  that  the  laticiferous 
tubes  are  more  nearly  emptied  by  its  adoption. 

The  above  refers  to  the  more  complex  type  of  drip-tin,  but 
several  others  designed  on  an  improved  and  simpler  plan  and  more 
suitable  for  coolies  have  already  been  made  in  Ceylon.  They  are 
useful  but  are  not  largely  adopted  in  the  East. 

Collecting  Cups  and  Spouts. 

In  all  methods  it  is  necessary  to  fix  the  tins  or  spouts 
on  the  trees  and  therefore  to  have  some  sharp  point  to 
press  against  the  bark  for  fixing.  In  most  .systems  now 
in  vogue  a  spout,  preferably  of  aluminium,  is  fixed  at  the 
base  of  each  fine  and  the  tins  are  placed  on  the  ground  immediately 
under  the  spout  ;  this  arrangement  is  found  to  be  economical. 

The  advance  made  recently  in  cups  for  collecting  latex 
on  rubber  plantations  is  of  more  than  usual  interest.  Four  or  five 
years  ago  it  was  the  custom  to  use,  on  many  Eastern  plantations, 
coconut  shells  in  preference  to  the  leaves  or  bamboo  cups  employed 
in  Brazil  and  Africa.  The  shells  were  popular  on  account  of  their 
cheapness  and  cleanl'ness,  and  were  replaceable  at  a  very  small 
cost.  Tin,  aluminium,  and  subsequently  galvanized  iron  and 
enamelled  cups  were  also  largely  used,  but  it  was  soon  found 
that  these  corroded,  and  were  apt  to  discolour  the  latex  or  scrap 
rubber  in  the  cups.  The  place  of  these  has  been  taken  by  glass, 
earthenware,  and  Chinese  paper  cups,  the  latter  being  preferred 
on  account  of  their  not  being  so  easily  broken  and  their  com- 
parative cheapness. 

Number  of  Collecting  Cups  Required. 

Having  run  through  a  good  variety  of  utensils  and  selected 
what  appear  to  be  reliable  forms  of  collecting  cups,  the  planters 
are  now  engaged  in  evolving  a  scheme  whereby  theft  can  be 
reduced  to  the  minimum,  and  cleanHness  maintained.     The  systems 


2i6  PARA    RUBBER 

adopted  on  two  Malayan  estates  may  be  compared.  In  both 
cases  only  one  cup  peT  tree  is  used ;  in  one  case  the  cup  when 
empty  is  turned  mouth  downwards,  and  placed  on  the  top  of  a 
stick  some  two  or  three  feet  from  each  tree,  and  projecting  about 
one  yard  above  the  ground  ;  in  the  other  case  each  empty,  clean 
cup  is  lodged  on  some  projection  from  the  tree  above  the  height 
of  the  tapping  area.  In  each  case  the  manager  can  see  all  the 
cups,  and  can  thus  detect  loss  by  theft  or  otherwise.  Further- 
more, the  cups,  being  upside  down,  are  clean  when  the  tapper 
commences  his  morning  round,  instead  of  being  partially  fiUed 
with  dirt  from  the  splashing  of  rain  on  the  ground,  fall  of  leaves,  etc. 
As  the  same  tree  is  not  tapped  morning  and  evening  of  the  same 
day,  one  cup  per  tree  should  suffice  under  this  system.  We 
cannot  see  the  reason  for  some  planters  insisting  on  two  collecting 
cups  for  each  tree  tapped  on  alternate  days. 

Glass  and  Earthenware  Cups. 

The  importance  of  cleanliness  in  all  departments  of  estate 
work  has  been  so  well  recognised  that  even  enamelled  collecting 
cups  and  coagulating  dishes  are  being  superseded  by  others  made 
of  glass.  Collecting  cups  to-day  are  of  a  varied  character.  The 
majority  of  estates  still  use  tin  or  iron  cups  and  will  probably  con- 
tinue doing  so  until  the  utensils  have  been  worn  out  ;  others  use 
coconut  shells  on  account  of  their  cheapness,  and  one  or  two  have 
adopted  enamelled  cups.  Undoubtedly  the  last  mentioned  is  the 
best  of  the  three,  but  I  believe  they  will  be  replaced,  in  very 
many  instances,  by  glass  or  earthenware  receptacles. 

In  tapping  operations  there  is  always  a  certain  amount  of 
sap  emitted  from  the  cortical  cells  ;  this  contains  various  acids 
which  become  mixed  with  the  latex  from  the  laticiferous  channels. 
The  acids  act  upon  the  tin  or  iron  cups  and  invariably  lead  to 
considerable  discolouration  in  the  latex  ;  subsequently  the  rubber 
is  often  stained  to  such  an  extent  as  to  lower  its  value.  When 
glass  cups  are  used,  no  such  chemical  reaction  can  take  place,  and  a 
pure  clean  rubber  should  result  from  their  use. 

Another  point  of  importance  is  the  ease  with  which  the 
glass  cups  can  be  cleaned.  After  each  day's  work  the  collectors 
have  to  pick  out  all  scrap  or  coagulated  rubber  in  the  cups  ;  often 
this  necessitates  some  amount  of  scraping  which,  with  receptacles 
other  than  those  made  of  glass,  results  in  exposure  of  surfaces 
readily  marked  by  acids.  It  is  obvious  that  glass  stands  first  in 
this  respect.  The  more  easily  the  collecting  cups  can  be  cleaned, 
the  less  likelihood  there  is  of  the  rubber  "being  stained  or  turning 
tacky.  Most  planters  now  recognise  that  in  the  handling  of 
latex  one  has  to  be  as  careful  as  in  a  dairy,  so  susceptible  are  its 
contents  to  decomposition.  Cleanliness  is  of  the  utmost  im- 
portance, and  the  use  of  glass  cups  will  materially  assist  planters 
anxious  to  turn  out  even-coloured  rubber. 

One  firm  has  devoted  considerable  time  and  attention  to  the 
manufacture  of  glass  collecting  cups  and  has  put   on  the  market 


PARA     RUBBER  217 

some  new  shapes  and  sizes,  not  only  for  collecting  the 
latex  at  the  base  of  the  tree,  but  also  for  use  higher  up  the 
trunks  of  the  trees.  Some  of  these  cups  (registered  designs)  are 
made  with  rims  and  holes  suitable  for  hanging  purposes.  They 
are  being  made  in  the  ordinary  clear  white  glass  and  also  in  light 
and  dark  green  and  amber  colours,  and  may  be  had  in  any  special 
pattern,  as  required.  Another  important  point  is  that  the  glass 
cups  can  be  supplied  with  the  name  of  the  estate  marked  on  them, 
so  that  they  are  easily  recognised. 

A  new  design  of  glass  collecting  cup  has  been  made  in 
the  half-lemon  shape,  and  is  equally  suitable  for  fixing  to  the 
tree  or  for  embedding  in  the  ground  at  the  foot  of  the  tree.  It  is 
moulded  with  two  rims  at  the  top,  between  which  a  string  or 
wire  can  be  passed  round  the  cup  and  the  tree,  so  that  it  can  be 
securely  attached  to  the  latter.  The  side  nearest  to  the  tree  is 
concave  and  fits  closely  to  the  bark  of  any-sized  tree,  permitting 
all  the  latex  to  run  into  the  cup  and  not  trickle  down  between 
the  bark  and  the  cup,  as  is  the  case  with  circular  cups.  These 
cups  do  not  require  any  hole  upon  which  to  hang  them.  This 
obviates  the  damage  to  the  bark  of  the  tree,  as  no  nail  is  necessary. 
The  shape  of  the  bottom  of  the  cup  is  also  a  considerable  im- 
provement, as  it  combines  the  advantages  of  the  two  different 
cups  which  are  often  used,  one  for  above  and  another  for  the 
base  of  the  tree.  The  cups  are  strongly  made  in  clear  white, 
amber,  or  green  colours,  and  are  shaped  so  as  to  pack  easily  one 
within  the  other. 


CHAPTER    XI. 

WHERE     TO     TAP. 

It  is  weU  known  that  in  Hevea  brasiliensis  the  latex  occurs  in 
all  parts  of  the  stem  and  branches  and  in  the  leaves.  But  the 
quality  and  quantity  of  the  latex  in  the  leaves,  young  twigs,  and 
branches  are  such  as  to  render  the  collection  from  these  areas 
unremunerative.  The  more  or  less  successful  production  of  gutta- 
percha from  leaves  led  many  to  anticipate  that  rubber  might  be 
obtainable  from  the  foliage  and  young  twigs  of  Hevea  brasiliensis. 

The  latex  in  young  tissues  and  fohage  is  never  abundant  and 
is  said  to  clot  in  httle  lumps  where  it  exudes.  The  rubber  from 
these  structures  is  adhesive  and  has  less  elasticity  and  strength 
than  that  from  the  trunks  of  mature  trees.  It  may  be  safely 
asserted  that  the  collection  of  latex  from  this  species  must  be 
made  from  the  stem,  and  in  some  cases  perhaps  the  main  branches, 
and  that  all  other  parts  may  be  neglected  as  sources  of  paying 
quantities  of  marketable  rubber.  In  practice  it  is  easier  to  tap 
the  stem  from  six  feet  downwards  than  any  other  part,  though  the 
erection  of  stands,  scaffolding,  and  the  use  of  ladders  and  walking 
stilts  for  tapping  higher  parts  and  thick  branches  have  been  attended 
with  good  results  in  some  cases.  Estates  are  known  where 
rubber  in  paying  quantities  has  been  obtained  from  six  to  twenty 
feet,  but  tapping  above  six  feet  is  not  generally  adopted.  The 
fact  that  from  20  to  over  30  lb.  of  rubber  per  tree  have  been 
obtained  from  the  lower  part  of  the  stem  alone  within  twelve 
months  makes  it  very  doubtful  whether  tapping  of  less  accessible 
parts  will  come  into  general  force  except  where  the  lower  part 
has  been  severely  mutilated  during  tapping.  The  strain  on  the 
plant  to  heal  the  wound  area  from  six  feet  downwards  is  quite  as 
much  as  it  need  stand.  Furthermore,  it  must  be  remembered  that 
the  maximum  quantity  of  latex  and  rubber  may  be  obtained  not 
so  much  by  tapping  virgin  areas  as  by  taking  advantage  of  the 
wound  response. 

Areas  Tapped  on  Estates. 

On  most  estates  in  the  East  tapping  is  done  only  from  the  base 
up  to  six  feet.  On  a  few  first-class  estates,  where  the  bark  in  this 
area  has  been  badly  tapped,  the  affected  trees  have  been  worked 
at  from  six  to  ten  feet  above  the  base  until  the  lower  areas  healed. 
Trees  three  to  four  years  old  are  tapped  from  the  base  up  to  two 
feet,  five-year-old  up  to  three  feet,  six-year-old  up  to  four  or  six 
feet.  On  only  one  or  two  estates  have  trees  under  three  years 
of  age  yielded,  when  tapped  towards  the  base,  pa3ang  quantities 
of  rubber.     The  low  percentage  of  trees  having  a  girth  of  18  inches 


PARA     RUBBER  219 

— below  30% — on  three  to  four-year-old  clearings,  prevents 
most  planters  from  economically  carrying  out  regular  tapping 
operations  at  that  age. 

Basal  Tapping  of  Young  Trees. 

Tapping  the  base  of  young  trees  has  been  extensively  done 
on  some  Malayan  and  Ceylon  estates,  with  what  results  to  the  tree 
only  the  future  can  tell.  It  has  been  contended  that  planters  will 
not  allow  any  latex  to  escape  if  it  is  at  all  possible  to  collect  it  at  a 
profit.  Certainly  the  tapping  of  the  basal  part  of  trees  which  are 
admittedly  too  thin  to  tap  at  the  usual  height  lends  colour  to  this 
declaration.  I  do  not  think  that  any  efforts  will  be  spared  to  secure 
the  maximum  quantity  of  rubber  from  trees  at  all  stages  of  their 
gr(  wth.  I  am  more  afraid  that  damage  may  be  done  to  the 
young  trees  by  thus  taking  advantage  of  a  difference  in  thickness 
of  the  bark  at  different  sections.  Most  managers  have  profited 
by  experience  already  gained  in  the  tapping  of  very  young  plants, 
and  are  now  inclined  to  let  the  trees  have  the  very  best  chance  to 
develop  into  the  strongest  types  so  that  a  regular  output  of  rubber 
can  be  reasonably  anticipated  during  the  years  to  come.  There 
are  no  data  available  which  would  lead  one  to  believe  that  the 
latex  at  the  base  of  a  four-year-old  tree  would  vanish  if  not 
immediately  collected.  The  latex,  if  left  alone  for  another  year, 
would  probably  increase  in  quality  and  quantity. 

The  following  experiments  (L'Hevea  Asiatique,  M.  Collet), 
indicate  that  the  lower  part  up  to  60  cm.  (i  cm.  equals  0-39  inch) 
yields  considerably  more  rubber  than  the  higher  parts  : — 

Number  of  Yield  of  Latex 

Incisions.  Area  tapped.  in  grammes. 

I20  ..  o  to     60cm.  ..  222644 

100  ..  60  to    120  cm.  ..  iiii'og 

120  ..  120  to    180  cm.  ..  58743 

These  results  show  that  the  maximum  jneld,  per  given  area,  is 
to  be  obtained  from  the  base  up  to  a  height  of  about  five  feet. 
Other  experiments  have  proved  that  the  yield  from  the  base  to 
three  feet  is  considerably  more  than  that  from  three  to  six  feet. 
According  to  Tromp  de  Haas,  the  trees  in  Java  give  the  largest 
yield  in  their  lower  parts,  and  tapping  up  to  a  height  of  i'5  metres 
(5  feet)  gives  the  best  results. 

Experiments   in   Ceylon. 

Experiments  carried  out  in  Ceylon  strongly  support  the  same 
conclusion,  and  the  following  are  typical  examples  of  the  results 
obtained  by  Parkin  : — 

Number  of  Area  tapped.  Yield  of 

Incisions.  Latex  in  c.c. 

i26  ..  12  inches  from  base  ..  245 

26  ..  36       ,,  „  -.  180 

26  ..  72       „  .,  ••  18-5 

.14  ..  At  base  of  trunk  ..  300 

B     14  . .  At  48  inches  from  bcise    . .  140 

(14  . .  At  108  „  . .  ii'5 


220  PARA     RUBBER 

The  conclusions  which  Parkin  drew  from  his  experiments  were 
' '  that  there  is  a  greater  exudation  of  latex  from  wounds  made  at  the 
base  of  the  trunks  of  Hevea  trees  than  at  any  higher  region ;  that 
the  exudations  from  one  to  five  or  six  feet  up  the  trunk  differ  little  ; 
and  that  above  five  or  six  feet  the  latex  exuded  falls  off  very  con- 
siderably. ' '  Experiments  in  Malaya  have  shown  that  the  first 
four  feet  from  the  base  contain  the  maximum  amount  of  latex,  but 
a  height  of  six  feet  is  allowed  by  many  planters.  It  is  well  known 
to  planters  in  Ceylon  that  the  quantity  of  latex  obtained  at  five  to 
six  feet  from  the  ground  is  little  more  than  half  that  at  the  base  of 
the  trunk ;  nevertheless,  a  jdeld  of  over  i  to  3  lb.  of  rubber,  per 
tree,  is  expected  on  certain  estates  by  tapping  the  area  from  six  to 
ten  feet  above  ground. 

16  High  Tappings  give  3J  lb.  Rubber. 
It  is  of  considerable  interest  to  note  that  though  the  rubber- 
yielding  capacity  of  the  cortex  of  the  stem  generally  decreases 
from  below  upwards,  the  yield  of  rubber  obtainable  from  the 
higher  parts  of  single  trees,  similar  to  those  at  Henaratgoda,  is 
sometimes  surprisingly  large.  The  following  results  show  that 
as  much  as  35  lb.  of  rubber  were  obtained  from  one  tree  in  16  tapping 
operations  at  10  to  20  feet. 

Where  tapped.  Number  of  times                  Yield  of  Rubber 

tapped.  per  tree. 

6  to  16  feet  ..  16  ..  2lb.  Sj^oz. 

10  to  20  feet  ..  16  ..  3  lb.  3  oz. 

20  to  30  feet  . .  16  .  .  2  lb.  6  oz. 

Base  to  30  feet  . ,  23  . .  4  lb.  6  oz. 

Base  to  50  feet  . .  8  . .  i  lb.  10  oz. 

Experiments    at    Singapore. 

Ridley  (Straits  Bulletin,  July,  1910)  considers  that  tapping 
should  be  done  from  the  base  to  a  height  of  five  feet.  The  richest 
latex  is  got  from  the  part  nearest  to  the  base,  and  the  amount  of 
latex  per  incision  is  greater  at  that  level.  From  the  upper  branches 
the  weight  of  rubber  obtained  is  much  smaller,  while  in  young 
trees  the  flow  soon  ceases.  In  recommending  basal  incisions .  for 
young  trees,  he  further  points  out  that  there  is  quick  renewal  at 
the  base  and  less  distortion  of  the  bark. 

Best  Yielding  Areas. 

Experiments  to  prove  which  is  the  best  area  to  tap  have  been 
carried  out  by  many  observers.  The  larger  flow  at  the  base  of  the 
trunk  than  from  higher  parts  has  been  noticed  by  Parkin  and 
others  in  Ceylon,  by  Beaton  in  India,  by  Haas  in  Java,  by  Arden 
in  Malaya,  as  well  as  by  native  collectors  in  the  Amazon  valley. 
One  critical  observer  (T.A.,  August,  1910)  seems  to  doubt  this,  but 
does  not  give  original  results  to  support  his  view.  It  is  on  account 
of  this  that  the  idea  of  increasing  the  lower  tapping  area,  by 
pruning  the  young  plants  and  retaining  a  few  of  the  basal  shoots  to 
grow   into   leaders   in    after   years,   has   been    recommended,   for 


■^      ^^  V 


/  7<f./»  fry   Ti-nr  Etheri>Hil(in. 
TAPPING       A       30-YEAR.OLD       HEVEA       IN       CEYLON. 


TAPPING     FROM     BASE     TO     50      FEET. 


Photo  by  11.  F.  Maemillan. 
TAPPING     FROM     6    TO     16     FEET. 


PARA     RUBBER 


221 


instead  of  one  stem  there  would  be  two  or  three  available  for 
tapping.  If  only  one  stem  is  retained,  it  will  show  a  large  increase 
in  circumference. 


Yielding  Capacity  at  Different  Heights. 


The  yielding  capacity  of  Hevea  brasiliensis  is  influenced  by 
its  constitution  and  environmental  conditions,  and  it  may,  at  first, 
seem  impossible  to  arrive  at  any  reliable  conclusions  as  to  the 
rubber  capacity  per  unit  of  cortical  tissue.  Dr.  Tromp  de  Haas 
has  determined  the  rubber-yielding  value,  under  known  con- 
ditions, per  square  metre  of  cortex  for  certain  Hevea  trees  in 
Java.  A  latge  number  of  results  will  be  required  before  anything 
definite  can  be  asserted,  and  the  following  figures  should  be  useful 
for  comparison  with  those  of  other  observers.  The  experiments 
were  carried  out  at  Henaratgoda  between  September  26th,  1905, 
and  February  13th,  1906,  on  trees  15  to  20  years  old.  The  original 
groove,  about  one-quarter  of  an  inch  wide,  was  made  without 
obtaining  rubber  in  quantity  ;  in  subsequent  operations  the  bark 
was  removed  by  paring  only  when  the  yield  of  latex  obtained 
by  pricking  the  tubes  was  considered  too  small.  The  rubber  was 
therefore  obtained  more  by  incising  rather  than  excising  the  latex 
tubes. 


Yield  of  Rubber 

in  ounces,  per 

Tapping  Section. 

Area  excised  in 

Yield   of 

square   foot   of 

square  inches. 

Rubber, 
lb. 

47 '« 

cortex  removed. 

Base  to  5  and  6  ft. 

• .       7.348i 

14-8 

6  to  16  feet 

796* 

4f 

13-37 

10  to  20  feet 

1,4724 

6tk 

IO'26 

20  to  30  feet 

. .        i,424i 

4!J 

7-58 

Base  to  30  feet 

1,666 

4l 

6-05 

Base  to  50  feet 

2,726 

3i 

274 

These  experiments  lead  one  to  suggest  that  the  first  six  feet 
of  bark  produce  larger  proportions  of  rubber,  per  unit  of  excised 
bark,  than  any  other,  and  that  there  is  a  general  decrease  in  the 
rubber-yielding  capacity  of  the  bark  the  higher  one  goes  up  the 
stem.  In  the  above  results  one  can  discern  a  fairly  regular 
agreement.  Other  results  over  larger  surfaces  agree,  more  or  less, 
with  the  above,  except  that  the  average  yield  of  rubber  per 
square  foot  is  sometimes  higher  from  the  stem  between  6  to  16  feet 
than  that  here  given. 

The  trees,  on  account  of  their  age,  had  moderately  thick  bark, 
and  the  average  yields  per  square  foot  are  higher  than  those 
obtainable  from  younger  trees.  It  is  important  to  note  that  an 
average  yield  of  over  13  ounces  of  rubber  may  be  obtained 'per 
square  foot  of  excised  cortical  tissue  from  the  base  up  to  5  or  6  feet 
and  from  6  to  16  feet  from  the  base.  In  a  fairly  general  way  it  may 
be  stated  that  an  increase  in  circumference  of  five  inches  gives  an 
increase  in  the  basal  tapping  area  of  360  square  inches. 


Nature  of  Cut. 

Crude  Rubber 
in  Latex. 

0/ 

Resin  in  the 
Crude  Rubber. 

0/ 

Simple  three-inch 
cut. 

/o 
43-8 

2-27 

Herring-bone. 

44'4 

2- 12 

Herring-bone. 

39-8 

1-88 

222  PARA     RUBBER 

High  Tapping  Results  in  Malay. 
On  the  property  of  Highlands  and  Lowlands,  717  trees, 
probably  about  10  years  old,  were  tapped  six  feet  above  the 
former  tapping,  and  yielded  1,160  lb.  of  rubber.  The  rubber  was 
collected  by  720  coolies,  thus  giving  a  return  of  i-6  lb.  per  cooly 
during  the  three  months — the  period  of  the  tapping  referred  to. 

Results  of  Experiments  Regarding  Quality. 
The    following    experimental   tappings    by    Burgess    (Straits 
Bulletin,  May,   1904),  indicate  the  quality  of  the  rubber  from 
different  parts  of  the  plants  : — 

Position  of  the 
Cut. 

X.  A  large  root  exposed 
by  removal  of  some 
soil. 

8.  The  main  trunk  1-2 
feet  above  the  ground. 

3.  The  trunk  after  fork- 
ing 20  feet  above 
ground. 

' '  It  will  be  noted  that  the  latex  from  the  higher  portions  of 
the  trunk  is,  in  the  above  experiments,  poorer  in  rubber  than 
the  latex  from  lower  down — at  the  same  time  the  proportional 
amount  of  resin  in  the  latex  appears  to  decrease. 

Burgess's  results,  so  far  as  they  apply  to  the  resin  content, 
do  not  agree  with  those  obtained  by  Weber  in  the  case  of  Gastilloa 
rubber.  The  latter  found  that  the  percentage  of  resin  increases 
as  one  passes  to  younger  parts  of  the  same  tree.  The  percentages 
of  resin  were  :  trunk,  2-6i  ;  largest  branches,  3-77  ;  medium 
branches,  4-88  ;  young  branches,  5-86. 

The  latex  obtained  from  areas  twenty  feet  from  the  base,  in 
Hevea,  is  often  very  sticky  and  may  not  yield  good  rubber,  but 
this  is  by  no  means  always  the  case.  On  some  estates  in  the 
Ambalangoda,  Kalutara,  and  Matale  districts  of  Ceylon  the 
old  rubber  trees  are  said  to  give  latex  of  good  quality  from  six 
feet  upwards. 

It  has  been  previously  pointed  out  that  the  cortex  of  the 
seedlings  of  Hevea  brasiliensis  and  the  cotyledons  of  the  seed  itself 
possess  a  large  number  of  laticiferous  channels,  but  the  latex 
obtainable  therefrom  is  usually  very  sticky  and  the  dried  product  of 
low  commercial  value.  Rubber  prepared  from  two-year-old  trees 
of  Hevea  brasiliensis  is  sticky  and  easily  snaps  when  lightly 
stretched  ;  that  from  four- year-old  trees  or  from  stems  which  have 
a  circumference  of  about  twenty  inches,  though  it  does  not  possess 
the ,  properties  which  manufacturers  most  desire,  reahzes  a  price 
which  is,  to  the  producers,  satisfactory. 

Tacky  Rubber  from  First  Tappings. 
When  a  tree  is  tapped  for  the  first  time,  though  it  may  be 
4  or  29  years  old,  the  rubber  obtained  from  the  latex  is  apt  to 


PARA    RUBBER  223 

turn  soft,  sticky,  or  tacky,  on  keeping.  This  is,  in  all  probability, 
primarily  due  to  the  large  percentage  of  sap  contents  which  exude 
from  a  proportionately  large  surface  of  fresh  cortical  cells.  In 
subsequent  tapping  operations  fewer  cortical  cells  are  excised  and 
excess  of  sap  constituents  has  had  every  chance  to  escape.  Sap 
contents  are  usually  rich  in  soluble  food  materials,  notably  sugar 
and  mineral  matter. 

Occurrence  of  Non-coagulable  Latex. 

Ordinary  tappings  of  medium-sized  and  old  Hevea  trees 
usually  give  good  rubber  when  the  tapping  operations  are  carried 
out  on  the  basal  part  (base  to  5  or  6  feet)  ;  it  is  curious,  however, 
to  note  that  when  the  higher  parts  of  even  the  oldest  trees  in  the 
East  are  tapped  the  latex  obtained  often  appears  to  be  changed  in 
constitution.  The  latex  from  high  parts  of  very  old  trees  is  often 
very  watery,  and  possesses  a  low  percentage  of  caoutchouc  ;  on 
treatment  with  the  requisite  quantity  of  acetic  acid  coagulation 
does  not  take  place  ;  even  when  allowed  to  stand  for  several  days  a 
curdled  liquid  only  is  obtained,  the  particles  of  which  are  not 
elastic  and  do  not  adhere  to  one  another.  The  following  results 
were  obtained  in  Ceylon  : — 

Per  cent,  of 
Number  of  times      tappings  giving 
Number  of  times      when  latex  not         non-coagulable 
Height  of  tapping  area.  tapped.  coagulable.  latex. 

Base  to    5  or    6  feet  1,165  9  °'77 

6  to  16     ,,  95  I  105 

10 to  20     ,,  94  I  i'o6 

20  to   30       ,,94  2  2'12 

30  feet  171  24  i4'03 

50  ..  84  5  5"95 

The  number  of  times  when  non-coagulable  latex  has  been 
obtained  from  various  sections  of  the  stem  of  29-year-old  trees  is 
given  in  the  table  ;  in  considering  them  one  should  remember  that 
the  circumference  of  the  stems  at  the  highest  points  tapped  was 
not  less  than  30  inches.  It  will  be  obvious  that  this  phenomenon 
was  most  frequently  observable  in  connection  with  the  latex 
secured  when  tapping  from  the  base  to  a  height  of  30  and  50  feet. 


CHAPTER     XII. 

WHEN    TO    TAP. 

In  entering  upon  this  subject,  it  must  be  borne  in  mind  that 
there  are  three  main  points  at  issue.  First,  there  is  the  question 
of  the  age  and  size  of  a  tree  when  tapping  operations  may  be  com- 
menced, and  the  frequency  with  which  these  operations  may  be 
repeated  with  an  increase  in  age  and  girth.  Second,  the  seasons 
in  the  various  countries  must  be  considered  ;  for  while  most 
parts  of  Malaya  have  no  marked  seasons  and  tapping  can  be 
continued  throughout  the  year,  this  is  by  no  means  the  case  in 
parts  of  India,  Ceylon,  and  Java.  Third,  the  interval  between 
successive  tapping  operations  must  be  determiijed  in  conjunction 
with  many  factors  involving  considerations  of  rate  of  growth, 
composition  of  latex,  distance  between  tapping  lines,  and  thick- 
ness of  bark  parings. 

Importance  of  Age  and  Size. 

Ule  and  Seeligmann  state  that  in  the  Amazon  district  the  tree 
requires  15  years  to  come  to  tapping  maturity  in  open  plantations 
and  25  years  in  the  forest,  and  one  cannot  help  concluding  from  this 
statement  that  either  the  cultivated  plants  in  the  East  thrive  much 
better  in  their  land  of  adoption  than  the  wild  ones  in  their  native 
habitat,  or  that  the  collectors  are  less  eager  to  commence  tapping 
operations  in  the  Amazon  district  than  in  the  Middle-East. 

Cross  stated  that  in  Para  the  trees  were  tapped  if  they  had  a 
circumference  above  18  or  24  inches,  the  operations  being  carried 
out  until  the  trees  were  killed.  On  plantations  in  the  East  such 
dimensions  may  be  attained  in  four  to  six  years. 

Trimen,  in  1884,  beheved  that  the  trees  in  Ceylon  should  be 
ten  years  old  before  commencing  tapping  operations.  Recent 
advances  have  shown,  however,  that  five-year-old  trees  in  that 
island  can  be  economically  tapped,  especially  if  they  have  been 
grown  in  virgin  forest  clearings. 

Johnson  is  of  the  opinion  that  the  size,  and  not  the  age,  of  the 
tree  indicates  when  it  can  be  safely  tapped,  and  that  tapping  may  be 
commenced  when  a  tree  has  a  girth  of  20  to  24  inches  a  yard  from 
the  ground.  As  a  matter  of  fact,  basal  tapping  is  usually  com- 
menced when  the  trees  have  a  girth  of  from  15  to  18  inches,  and 
several  tapping  lines  are  worked  on  trees  of  the  girth  mentioned 
by  Johnson. 


PARA    RUBBER 


225 


Rubber  from  Young  Trees. 

If  one  studies  the  many  analyses  of  Castilloa  rubber  quoted  by 
^^'eber  and  the  pubUcations  of  the  West  Indian  Botanic  and  Agri- 
cultural Departments,  one  cannot  help  being  struck  wth  the  fact 
that  the  quality  of  the  rubber  from  Castilloa  trees  depends, 
in  almost  every  case,  on  the  age  of  the  trees.  In  some  cases  the 
rubber  from  old  trees  is  shown  to  contain  82 '6  per  cent,  of  caout- 
chouc and  7-4  per  cent  of  resin.  The  rubber  from  two-year- 
old  Castilloa  trees  has  been  shown  to  contain  42-33  per  cent,  of 
resin  as  against  7-21  per  cent,  for  eight-year-old  trees.  Decrease  in 
resin  content  with  increase  in  age  is  also  characteristic  of  rubber 
from  Ficus  trees. 

The  importance  of  age  is  further  exemplified  by  analyses 
showing  a  gradual  decrease  in  percentage  of  resinous  substances, 
which  occurs  with  an  increase  in  the  age  of  the  part  of  the  Castilloa 
tree  from  which  the  rubber  is  obtained,  the  young  twigs  yielding 
5-8  per  cent.,  the  large  branches  377  per  cent.,  and  the  main  trunk 
only  2-6i  per  cent,  of  resinous  substances.  If  the  rubber  contains 
a  very  high  percentage  of  resin,  it  is  usually  considered  inferior, 
and  is  in  some  cases  almost  useless.  Increase  in  age  is  certainly 
to  be  associated  with  an  improvement  in  the  physical  properties 
and  quality  of  the  rubber,  whether  one  considers  plantations  of 
different  ages  or  parts  of  the  same  tree. 

Composition   of   Hevea   Rubber  from  Trees  of   Different 

Ages. 


Moisture 

Ash 

Resin  by  acetone  extraction 

Proteins 

Rubber 


2  yrs.  old. 
070  % 
o'5o    ,, 
3'6o    „ 
4'oo    ,, 

9i'2o    ,, 


4  yrs.  old. 
0-65  % 
0-30    .. 

2'72'   „ 

94'58    .. 


6  yrs.  old. 

0-55  % 
o'40  ,, 
275  ., 
1-51  .. 
9479    .. 


lOOOO 

loooo 

lOOOO 

Resins    extracted    by    glacial 
acetic  acid 

Moisture 

Ash 

Resin    .  . 
Proteins 
Caoutchouc 

2  74%        • 
8  yrs.  old. 
0-85%        . 
o"i4    ,, 
2-66    „ 

175    ..        ■ 
9460    „ 

.           2-62%            .. 

10-12  yrs.  old. 

.          0-20% 

022    ,, 

226    „ 

297    „ 

■     94'35    ..       •• 

2-65% 

30  yrs.  old 
0-50% 
0-25    „ 

2'32     „ 

369     „ 

93'24    „ 

loo-oo 

lOO'OO 

loo-oo 

Nitrogen 


0-28% 


0-48% 


0-59% 


Young  Rubber  from  Ceylon. 


The  above  analyses  show  (Bamber)  the  composition  of  Ceylon- 
grown  Hevea  rubber  prepared  from  trees  varying  in  age  from  2  to  30 
years.  It  wi  1  be  noticed  that  the  two-year-old  rubber  does  not 
differ  conspicuously  from  the  older  mature  rubber.  The  analyses 
represent  the  composition  of  only  one  series  of  samples,  and  should 


226  PARA    RUBBER 

not  be  taken  as  showing  the  constant  composition  of  rubber  from 
trees  of  the  ages  quoted.  The  rubber  from  two-year-old  trees 
was  sticky,  and  snapped  when  sUghtly  stretched ;  it  was 
obviously  unfit  for  ordinary  use. 

Samples  of  plantation  rubber  from  four-year-old  trees  were 
many  years  ago  deprecated  in  certain  quarters,  and  in  one  case 
they  were  classed  as  being  similar  to  common  African  sorts  for 
hardness,  but  superior  in  cleanliness.  They  were  described  as 
being  soft,  and  would  not  stand  much  working  on  the  machine, 
while  the  value  put  upon  them  was  only  equal  to  that  for  ' '  Congo 
ball  or  a  similar  quality  of  African. ' ' 

Parkin  proved  that  the  preparation  of  good  rubber  from  young 
stems  and  leaves  of  Hevea  brasiliensis  was  an  impossibility,  and 
other  observers  have  shown  that  rubber  from  young  trees  is 
adhesive  and  lacks  the  required  elasticity  and  strength  ;  never- 
theless, it  is  still  the  subject  of  much  discussion  as  to  whether  age 
is  the  only  criterion  for  cultivators  of  Hevea  in  the  East. 

Young  Rubber  from   Malaya. 

Clayton  Beadle  and  Stevens  (I.R.J.,  Jan.  28th,  1911),  state 
that ' '  determinations  carried  out  on  trees  about  four  years  of  age, 
and  just  brought  into  tapping,  yielded  in  one  series  of  experiments 
22  to  25  per  cent,  and  in  another  27  to  33  per  cent,  of  dry  rubber 
in  the  latex.  The  trees  were  tapped  every  day  and  on  different 
systems,  but  not  heavily.  The  results  are  the  average  figures  over 
periods,  of  some  months.  The  figures,  taken  in  conjunction  with 
others,  where  the  trees  were  older,  but  tapped  under  similar 
conditions,  show  that  the  latex  from  very  young  trees  is  poorer 
in  caoutchouc  than  that  from  older  trees. ' ' 

Their  analyses  of  latex  from  four  and  ten-year-old  trees  were 
as   follows  : — 

Trees  four  Trees  ten 

years  old.  years  old. 

0/  0/ 

/o  /o  . 

Water  . .  . .  . .  . .  . .  yo'oo  6000 

Acetone  extract  (resin) 
Protein 

Ash 

Caoutchouc  (by  difference) 

These  latices  were  also  dried  and  examined 


i'22  1-65 

1 47  2-03 

024  070 

27'°7  3562 


Dried  Latex  Dried  Latex 

from  trees  four  from  trees  ten 

years  old.  years  old. 

0/  0/ 

Acetone  extract  (resin)           ..  4-06  413 

Protein            490  508 

Ash 080  175 

Caoutchouc  (by  difference)    ..          ..  9024  89-04 

It  was  reported  by  Mr.  E.  B.  Davis,  director  of  the  General 
Rubber  Company,  New  York,  to  Mr.  Maude  of  the  Cicely  estate, 
after  a  series  of  tests  upon  rubber  from  4^,  5,  9,  10,  17,  and  27- 
year-old  trees,  that  the  rubber  from  young  trees  is  not  materially 
different  from  that  of  older  trees. 


PARA     RUBBER  227 

One  manufacturer  is  reported  (I.R.W.,  December,  1905)  as 
saying  that  the  rubber  does  not  attain  its  full  strength  unt  1  the  tree 
is  at  least  8  or  g  years  old,  and  materi?.!  from  younger  trees  ' '  has 
not  the  strength  of  hard-cure  Madeira  Ime  Para,  and  is  uneven  in 
strength. ' '  This  inferiority  is  not  seriously  reflected  in  the 
prices  paid  for  the  produce.  It  is  also  asserted  that  there  is  no 
difference  noticeable  in  the  rubber  from  8-year-old  trees  from 
different  plantations,  and  that  it  is  not  safe  to  use  it  for  the  finest 
work,  such  as  thread  and  the  best  bladders. 

Stanley  Arden  has  shown  that  in  parts  of  Malaya  the  rubber 
from  trees  3^  to  4  years  old  is  decidedly  inferior.  His  results  have 
been  quoted  in  the  section  dealing  with  yields  in  Malaya,  and  it 
is  only  necessary  to  point  out  that  the  yield  from  trees  up  to  four 
years  old  was  exceedingly  small  and  that  rubber  in  paying  quantities 
was  obtained  only  when  the  trees  were  about  or  over  seven  years 
old.  He  calculated  that  by  the  time  the  trees  in  Malaya  are  six 
years  old,  75  per  cent,  should  give  an  average  yield  of  12  ounces. 

Recent  events  have  nevertheless  shown  that  the  rubber  from 
'  four- year-old  Hevea  trees  in  Malaya,  if  properly  prepared,  com- 
mands a  very  satisfactory  price.  Furthermore,  a  yield  of  one 
pound  of  dry  rubber,  per  tree,  has  been  obtained  from  a  large 
number  of  trees  in  Selangor  and  elsewhere,  before  they  attained 
their  fifth  year. 

Age  and  Size  Considered. 

With  regard  to  experience  in  Ceylon  it  should  be  pointed 
out  that  under  favourable  circumstances  the  Hevea  rubber  tree 
will  show  an  increase  in  circumference  of  about  4  to  5  inches  per 
year  up  to  the  first  six  or  eight  years,  and  that  though  the  rubber 
from  two-to  six-year-old  trees  is  adhesive,  and  may  have  a  high, 
percentage  of  resinous  compounds,  it  is  by  no  means  always  the 
case.  The  analyses  of  Hevea  rubber  from  2,  4  and  6-year-old  trees- 
have  been  previously  given,  and  though  the  results  cannot  be 
accepted  as  conclusive,  it  was  pointed  out  by  Bamber  that  the 
rubber  did  not  possess  a  very  high  percentage  of  resin,  and  in  this 
respect  was  certainly  quite  contrary  to  what  Weber  and  others 
have  observed  in  the  rubber  from  young  Castilloa  trees.  But 
when  one  considers  that  the  rate  of  growth  of  the  Hevea  rubber 
tree  in  Ceylon  is  such  that  a  circumference  of  18  inches  cannot 
be  attained  much  before  the  fourth,  fifth,  or  sixth  year,  it  is  obvious 
that,  under  ordinary  methods  of  cultivation,  all  ideas  of  extracting 
rubber  from  trees  under  these  ages  should  not  be  encouraged. 

Parkin  suggests  (Science  Progress,  April,  '  1910)  that  the 
inferiority  of  rubber  from  young  stems  and  shoots  may  be  associa- 
ted with  the  fact  that  the  latex  is  contained  chiefly  in  tubes 
formed  in  primary  growth.  The  latex,  in  young  trees,  will  mingle 
with  that  from  tubes  formed  during  secondary  growth. 

Minimum  Size  for  Tapping. 

If  the  tree  has  a  circumference  of  much  less  than  20  inches, 
systematic  tapping  cannot  be  recommended,  because  the  available 


228  PARA     RUBBER 

tapping  area  is  so  small ;  nevertheless,  on  several  estates  the  trees 
having  a  circumference  of  only  15  to  18  inches  are  tapped.  The 
production  of  new  tissue  is  a  strain  on  the  young  plant,  and  the  thin 
bark  tissues  are  quickly  cut  away  long  before  the  desired  quantity 
of  rubber  has  been  obtained. 

If  the  circumference  is  20  inches  a  yard  from  the  ground,  and 
the  tree  is  four  years  old,  it  can  be  tapped.  I  have  seen  good 
rubber  from  such  trees.  A  tree  24  inches  in  circumference  should 
not  have  more  than  five  tapping  lines.  It  could  be  tapped  on 
the  "herring-bone  system  on  one  or  both  sides  of  the  tree. 

On  one  estate  in  Ceylon  41  trees  of  considerable  height,  but 
having  a  circumference  of  from  18  to  25  inches  a  yard  from  the 
ground  gave  with  very  light  tapping  during  March  and  April  19^  lb. 
of  dry  rubber. 

From  the  foregoing  remarks  it  is  clear  that  the  questions  of 
available  tapping  area  and  size  cannot  be  neglected  ;  they  are  as 
important  as  the  ages  of  the  trees.  A  minimum  circumference  of 
from  15  to  18  inches  a  yard  from  the  ground,  and  a  minimum 
age  of  3  to  ^5  years  can  be  accepted  for  most  rubber  properties,  the 
better  developed  trees  being  tapped  first. 

It  is  generally  conceded  that  the  minimum  girth  at  which 
tapping  may  commence  in  Malaya  is  15  to  18  inches  a  yard  from 
the  ground,  this  being  attained  when  the  trees  are  about  3J  to  4 
years  old  on  good  estates.  In  Ceylon,  especially  where  the  Hevea 
trees  have  been  planted  among  old  tea,  or  at  high  elevations  in 
South  India,  East  Java,  and  Ceylon,  the  trees  may  sometimes  not 
attain  this  size  until  they  are  quite  six  or  even  seven  years  old. 
Tapping  at  the  base  under  these  circumstances  is  sometimes  done 
when  the  trees  are  15  and  16  inches  girth  a  yard  from  the  ground. 

Minimum  Percentage  of  Trees  for  Tapping. 

While  the  minimum  girth  for  the  commencement  of  tapping 
operations  in  Malaya  is  agreed  upon,  there  is  still  to  be  considered 
the  important  question  of  the  percentage  of  trees  on  the  estate 
which  have  attained  the  required  circumference.  Tapping  cannot 
be  economically  carried  out  with  only  30  per  cent,  of  the  trees 
of  the  tappable  size.  At  a  recent  planters'  conference  in  Malaj'a, 
Baxendale  stated  that  if  65  per  cent,  of  the  trees  had  a  girth  of  18 
inches  tapping  could  be  commenced.  Duncan,  while  expressing 
his  unwillingness  to  tap  young  trees,  would  not  mind  tapping  trees 
with  a  minimum  girth  of  16  inches  if  80  per  cent,  of  the  trees 
were  of  that  size. 

How  TO  increase  the  Tapping  Area. 

The  foregoing  statements  refer  to  trees  of  known  ages  that 
have  attained  the  minimum  circumference  when  allowed  to 
develop  very  long  and  slender  stems.  But  it  has  been  pre\'iously 
remarked  that  by  pruning  the  trees  at  a  certain  stage  the  plant 
may  be  made  to  increase  in  girth  at  the  expense  of  the  longitudinal 
growth  ;  a  very  striking  illustration  of  this  is  to  be  seen  in  the  first 


PARA     RUBBER 


229 


clump  of  old  Hevea  rubber  trees  in  the  Henaratgoda  Garden, 
Ceylon.  The  dimensions  of  forked  and  straight-stemmed  trees 
on  various  estates  in  Ceylon  have  been  previously  given. 

In  the  particular  group  referred  to,  the  majority  of  the  trees 
have  long  straight  stems,  unbranched  to  a  height  of  30  to  60  feet. 
But  in  addition  to  these  there  are  a  few  which,  from  some  cause 
or  other,  have  forked  at  from  7  to  11  feet  from  the  ground,  and  in 
all  these  cases  the  trunks  are  conspicuously  larger  in  circumference 
and  therefore  present  an  increased  tapping  area.  The  following 
are  the  girths  at  3  feet  of  some  of  the  low-branched  and  straight- 
stemmed  trees  : — 


Trees  with 

long  straight 

Stems. 

Tree  forked  at 

II  feet  from 

Base. 

Tree  forked  at 
7  feet  from 
Base. 

Tree  forked  at 
9  feet  from 
Base. 

in. 
61,  65,  83,  85,  76 

in. 
log 

in. 
104 

in. 
109 

In  all  instances  those  trees  which  have  forked  near  the  ground 
have  a  much  larger  basal  circumference.  It  does  not  need 
any  argument  to  prove  that  an  increase  in  circumference  of 
over  30  inches  is  an  advantage,  and  the  fact  that  such  an 
increase  has  occurred  in  the  tapping  areas  of  trees  about  30 
years  old  is  sufficiently  encouraging  to  tempt  the  planter  to 
carry  out  a  few  bud-pruning  experiments,  once  his  trees  have 
attained  a  height  of  about  ten  to  twenty  feet.  The  buds  which 
appear  in  undesirable  places  can  be  removed  by  "thumb-nail" 
pruning.  Experiments  have  been  made  with  young  trees  in  their 
first  and  second  years,  and  in  each  case  the  increased  rate  of 
circumference  has  been  obtained  in  trees  within  the  second  year. 
In  dealing  with  young  plants  it  is  an  easy  matter  to  nip  off  the 
terminal  bud  of  the  main  stem,  when  the  desired  height  has  been 
obtained  ;  this  is  usually  followed  by  the  development  of  lateral 
shoots,  the  growth  of  which  should  be  encouraged  according  to 
circumstances.  An  increase  in  the  number  of  lateral  shoots 
means  an  ultimate  increase  in  the  foliage,  and  it  is  on  this  point 
that  the  success  of  the  work  depends.  The  pruning  should  be 
carried  out  in  such  a  manner  that  the  resultant  plant  has  an  in- 
creased quantity  of  foliage,  whereby  a  larger  food  supply  can  be 
built  up  for  the  benefit  of  all  parts  of  the  tree.  If  the  work  is  done 
in  such  a  manner  as  to  deprive  the  plant  of  its  leaves  for  a  long 
period  of  time,  the  growth  of  the  stem  will  be  temporarily  checked, 
and  the  immediate  increased  rate  of  growth  of  the  stem  tissues 
cannot  be  expected. 

The  Best  Season  to  Tap. 

The  trees  of  Hevea  hrasiliensis  exhibit  a  definite  foliar,  flower 
and  fruit  periodicity  ;  and  though  they  will  stand  tapping  through- 
out the  year,  it  is  questionable  whether  periodicity  in  tapping 
should  not  be  done  in  association  with  that  of  the  plant.  The 
trees  should  be  tapped  at  a  time  when  the  bark  is  most  quickly 
renewed,  in  order  that  cortical  tissues  may  be  formed  wherein  new 


230  PARA    RUBBER 

latxifers  can  be  produced.  The  periodicity  of  the  trees  varies 
according  to  chmatic  and  other  factors,  and  the  period  including 
the  fall  of  leaf,  the  leafless  phase,  and  that  of  fohar  renewal  appears 
to  be  the  most  critical  one.  In  most  parts  of  the  Straits  Settle- 
ments, according  to  Ridley,  from  December  to  March  is  probably 
the  resting  or  relatively  inactive  period,  and  the  bark  renewal 
during  these  months  cannot  take  place  as  rapidly  as  during  the 
rest  o  the  year.  One  observer  records  that  experiments  on 
17-year-old  trees  in  Krian  indicated  a  decrease  in  yield  during  the 
leafless  period,  and  also  during  the  fruiting  period.  On  a  large 
estate  every  planter  is  aware  of  the  fact  that  it  is  impossible  to 
entirely  suspend  tapping  operations  during  any  month  of  the 
year,  but  the  above  consideration  should,  whenever  practicable, 
be  allowed  for.  The  periodicity  in  estate  crops  noticeable  in 
March,  1911,  was  due  to  the  effect  of  drought,  and  Malcolm 
Gumming  stated  that  he  would  in  future  be  prepared  to  advise 
that  tapping  be  stopped  during  the  dry  period  of  foliar  renewal. 

Witt  points  out  that  in  the  Amazonas  careful  proprietors 
often  suspend  tapping  during  the  fruiting  period — August  to 
September.  The  same  principle  appears  to  have  actuated  many 
planters  who  believe  in  stopping  tapping  when  the  trees  are 
leafless,  a  period  of  some  two  or  three  weeks  each  year.  The 
experiments  which  have  been  continuously  carried  on  for  some 
18  months  on  17-year-old  trees  at  Krian  show,  according  to 
Carruthers,  a  shght  decrease  of  yield  during  the  leafless  period. 
The  notion  is  also  prevalent  that  tapping  should  be  discontinued 
during  the  fruit-bearing  period.  The  figures  obta'ned  at  Krian 
show  a  decrease  during  the  time  the  trees  were  in  fruit,  but  not  a 
decrease  sufficient  to  seriously  increase  the  cost  of  tapping. 

In  the  Amazon  valley  the  native  collectors  never  tap  the 
trees  when  in  flower,  as  they  believe  the  amount  of  rubber  then 
obtainable  is  much  less  than  at  other  times — an  idea  supported  by 
Ridley's  experiments  at  the  Botanic  Gardens,  Singapore. 

Tapping   during   Leaf-Change. 

Ridley  (Straits  Bull.,  May,  1903),  remarks  :  ' '  Mr.  Larkin, 
whose  estate  at  Castlewood  I  have  visited,  told  me  that  during 
the  late  dry  month  of  March  all  his  trees  in  one  part  of  the  estate 
shed  their  leaves  simultaneously,  and  remained  bare  for  a  time. 
He  continued  to  tap  during  this  period  and  found  no  diminution 
in  the  amount  of  latex  produced. ' ' 

If  yield  is  in  relation  to  turgidity  it  should  be  largest  when 
the  trees  are  leafless,  as  they  cannot  then  lose  much  water  by 
transpiration  ;  it  is  of  interest  to  note  that  the  experiments  made 
by  Arden  in  1902  seem  to  give  support  to  this  view.  Arden  states 
that  the  yield  from  trees  tapped  when  they  were  leafless  was 
much  greater  than  that  from  trees  tapped  when  the  leaves  were 
beginning  to  appear  or  when  in  full  foliage.  In  Nicaragua  the 
latex  from  other  rubber  trees  contains  the  highest  percentage  of 
caoutchouc  during  the  dry  season.    The  possession  of  abundance 


PARA     RUBBER  231 

of  latex  during  the  dry  season  may  lend  support  to  the  theory 
that  it  functions  as  a  water-store  during  drought. 

Tapping   During   Leaf-Change  and   Drought. 

In  many  parts  of  the  tropics,  however,  the  leafless  period 
occurs  when  rhe  dryness  and  temperature  of  the  air  are  at  the 
maximum,  and  the  collecting  of  latex  would,  during  such  a  time, 
be  limited  to  the  very  early  part  of  the  day  and  evening.  The 
results  quoted  elsewhere  tend  to  show  that  the  best  flow  of  latex  is 
obtained  in  Ceylon,  when  the  air  and  soil  are  abundantly  sup- 
plied with  moisture  and  when  the  temperature  is  comparatively 
low.  A  period  of  drought  lasting  only  seven  or  twelve  days 
appreciably  effects  the  flow  of  latex,  but  though,  under  such  con- 
ditions, the  quantity  is  reduced,  the  quality  is  usually  improved. 
The  latex  dries  rapidly  on  the  tree  in  hot,  dry  weather  ;  this  can, 
however,  be  overcome  by  the  use  of  ammonia,  formalin,  &c.,  placed 
in  the  drip-tins  at  the  top  of  each  incision. 

Effect  of  Humidity  on  Yield. 

Several  writers  have  associated  the  yield  of  latex  with 
atmospheric  conditions,  the  general  contention  being  that  a  low 
temperature  in  the  tropics  and  plenty  of  moisture  were  conducive 
to  a  copious  and  more  or  less  continuous  exudation  of  latex. 
During  hot  dry  weather  the  amount  of  water  lost  by  transpiration 
from  the  leaves  is  very  great,  and  it  has  been  argued  that  this 
loss  reduces  the  tension  in  the  cortex  and  therefore  in  the  latex 
tubes  ;  hence  the  poor  flow  obtained  during  such  times. 

Dr.  Haas,  as  a  result  of  his  experiments  in  Java,  concludes 
that  if  the  humidity  of  the  soil  is  great,  and  if  the  rains  are 
equally  distributed,  the  difference  in  yield  during  the  year  is  not 
great,  and  he  further  states  that  though  the  best  times  for 
tapping,  in  Java,  are  at  the  beginning  and  the  end  of  the  wet 
season,  in  wet  years  it  does  not  matter  when  the  trees  are  tapped. 

Seasonal  Tapping  and  Rainfall  in  Malaya. 

At  a  conference  of  Malayan  planters  Baxendale  stated  that 
an  average  of  nine  pounds,  per  acre,  per  month,  during  the  first 
three  months'  tapping  of  four  old  trees  was  the  lowest  yield 
he  had  experienced.  While  it  may  be  asserted  that  a  large  and 
well-distributed  rainfall  is  essential,  the  benefit  is  not  always 
immediately  apparent.  He  found  the  yield  per  cooly  in  the 
wettest  month  in  one  year  considerably  below  the  average.  When 
the  trees  became  very  wet,  the  latex  washed  over  the  cuts  and 
spread  itself  in  such  a  fine  layer  down  the  bark,  that  it  was  most 
difficult  to  collect,  even  as  scrap.  This  has  not,  however,  any 
adverse  effect  on  the  jaeld.  For  two  years  his  highest  5delds,  not 
only  by  the  cooly,  but  also  by  the  acre,  were  in  February  and 
March,  when  wintering  of  the  trees  was  general.  Parkinson  and 
Carey  stated  that  they  obtained  their  best  yields  in  wet  weather. 


232  PARA    RUBBER 

Experiments  at  Singapore. 
In  this  connection  some  useful  information  was  published 
by  Messrs.  H.  N.  Ridley  and  R.  Derry  (Straits  Bull.,  Dec,  1904). 
These  authorities  state  that  the  results  show  that  there  is  much 
difference  in  the  amount  of  rubber  obtained  from  the  same  quantity 
of  latex  at  different  times  of  the  year,  at  different  times  of  the 
day  (i.e.,  at  morning  and  evening  tappings),  and  from  the  same 
group  of  trees  when  they  have  had  a  sufficient  interval  of  rest  and 
when  they  have  not.  This  is  explained  by  stating  that  ' '  although 
in  over-tapping  latex  is  renewed  in  the  bark  quickly,  caoutchouc 
takes  much  longer  to  produce,  though  it  does  not  seem  in  the 
worst  cases  ever  to  be  entirely  absent  from  the  latex.  Thus  in  a 
trial  of  the  spiral  method  of  tapping  on  the  largest  tree  in  the 
Botanical  Garden  they  obtained  from  the  first  period  of  tapping 
531  fluid  oz.  of  latex  giving  9  lb.  of  rubber,  and  from  the  second 
period  of  tapping,  one  month  afterwards,  433  oz.  of  latex,  giving 
only  4  lb.  15  oz.  of  rubber,  the  ratios  of  caoutchouc  to  latex  com- 
paring as  3  {-Jf  fluid  ounces  to  one  ounce  dry  rubber,  as  against 
5yV  fluid  oz.  to  the  same  amount  of  rubber.  It  is  therefore  of 
the  greatest  importance  to  the  cultivator  to  avoid  tapping  at 
the  wrong  season  when  he  is  very  liable  to  interfere  with  the 
special  physiological  processes  in  the  trees  then  performing  their 
functions.  The  bark  of  the  tree  does  not  recover  as  well  from 
wounds  during  the  resting  period  between  December  and  March, 
nor  does  it  appear  that  the  return  of  caoutchouc  is  as  good.  Rapid 
and  good  renewal  of  the  bark  is  very  necessary,  not  only  to  protect 
the  wound  from  injurious  attacks  of  fungi,  but  also  to  increase  the 
production  of  caoutchouc.  Too  frequent  or  prolonged  tapping 
is  not  only  injurious,  but  produces  a  latex  inferior  in  quality. 

Seasonal   Results   at  Henaratgoda. 

Regarding  this  question  the  results  given  below  may  be  of 
value.  The  trees  marked  "  H  "  were  first  tapped  when  the  leaf-fall 
commenced,  and  the  operations  were  continued  through  the  period 
of  leaf- fall  and  renewal.  The  trees  marked  "  I "  were  tapped  from 
the  first  of  October  right  through  the  rainy  and  dry  seasons  ;  on  a 
few  days  tapping  was  not  carried  out  owing  to  inclement  weather. 

Yield  of  Dry 
Number  of  Times  Rubber 

tapped.  per  5  trees, 

lb.    oz. 
Trees  tapped  every  day  from  October 

I.  1905  (I)  157  .  .  38     I2| 

Trees  tapped  every  day  ;  first  tapped 

on  February  I,  1906  (H)  ..  68  13     14I 

The  tapping  operations  (I)  were  continued  at  Henaratgoda 
right  through  the  dry  months  of  January  to  April ;  towards  the 
end  of  the  latter  month  the  flow  of  latex  was  not  copious,  and  in 
some  cases  the  coagulation,  instead  of  being  complete  in  24  hours, 
required    a    period    of    nearly   two    days.     The    trees    had    been 


PARA     RUBBER  233 

regularly  tapped  from  September,  1905,  to  April,  1906,  during 
which  period  they  shed  all  their  leaves  and  produced  new 
foliage  and  also  flowers. 

On  estates  possessing  rubber  only  it  is  difficult  to  see  how  the 
labour  can  be  employed  if  tapping  is  suspended  during  the  leafless 
stage  or  the  dry  months,  and  the  point  to  determine  is  the  maxi- 
mum frequency  that  the  trees  can  be  tapped  with  the  minimum 
damage  to  the  tree  during  these  months. 

Further  Seasonal  Results  at  Henaratgoda. 

The  tapping  experiments  conducted  at  Henaratgoda  from 
June,  1908,  to  February,  1911,  by  Bamber  and  Lock  (Circular 
R.B.G.,  No.  18,  Vol.  v.),  led  them  to,  among  others,  the  following 
conclusions  : — 

"There  is  a  sHght  but  definite  seasonal  variation  in  yield, 
which  rises  to  a  maximum  about  December,  and  falls  to  a  minimum 
about  May. 

"Although  cHmatic  conditions  have  an  undoubted  effect 
upon  yield,  there  is  no  close  relation  to  be  traced  between  rainfall 
and  yield  for  particular  months. ' ' 

What  Part  of  the  Day  to  Tap. 

The  best  flow  of  latex  with  the  minimum  quantity  of  scrap 
rubber  is  obtained  in  the  early  morning  or  evening  on  sunny  days, 
but  tapping  may  be  done  further  on  into  the  day  when  the  temper- 
ature is  low  and  clouds  and  moisture  are  abundant.  In  a  district 
like  Peradeniya  tapping  may  be  continued  up  to  8  or  10  a.m., 
and  re-commenced  at  3  to  4  p.m.  Wickham  states  that  Hevea 
bleeds  most  freely  at  or  before  sunrise.  All-night  tapping  is  of 
course  only  possible  when  the  artificial  lighting  of  estates  is  more 
perfect  than  at  present.  The  best  times  for  tapping  in  Malaya 
are  given  by  some  planters  at  from  6.30  to  9.30  a.m.  ;  and  by 
others  at  5  to  10  a.m. 

In  the  early  and  late  parts  of  the  day  the  temperature  is 
lower,  the  air  usually  more  moist,  and  there  is  less  transpiration 
of  water  from  the  leaves  ;  the  combined  effect  of  these  factors  is  a 
better  flow  of  latex  during  such  times.  According  to  Ridley 
(Ann.  Rep.  Bot.  Garden),  the  girth  of  the  tree  decreases  during 
the  day  and  increases  towards  evening,  an  observation  which 
may  throw  some  light  on  the  theories  regarding  tension  of  the 
laticiferous  tissue  and  transpiration. 

Ridley  also  states  (Ann.  Rep.  Bot.  Gardens,  for  1904)  that 
the  most  favourable  times  for  tapping  are  morning  and  evening. 
From  the  same  number  of  trees  which  produced  a  total  amount 
of  578  lb.,  the  morning  trees  realized  314  lb.,  while  the  evening 
trees  gave  only  263  lb.,  showing  a  difference  in  favour  of  the  morn- 
ing tapping  of  51  lb.  Ridley  and  Derry  concluded  that  evening 
tappings  to  be  successful  should  be  deferred  to  as  late  an  hour  as 
possible. 


834  PARA     RUBBER 

Later  experiments  at  Singapore  (Straits  Bulletin,  July,  1910) 
show  a  slightly  higher  balance  than  this  in  favour  of  morning  tapping 
One  lot  of  trees  gave  no  lb.  15  J  oz.  of  dry  rubber  in  the  mornings 
and  90  lb.  2J  oz.  in  the  evenings.  Another  gave  109  lb.  10^  oz. 
in  the  mornings  and  85  lb.  14  oz.  in  the  evenings. 

Vernet  (Jour.  d'Agric.  Tropicale,  April,  1910)  tapped  three 
trees  at  Suoi  Gaio,  South  Annam,  and  got  the  markedly  different 
yields  of  296  c.c.  of  latex  in  the  mornings  and  91  c.c.  in  the  evenings. 
He  asserts  that  constant  great  humidity  reduces  the  difference. 

On  the  Mergui  Rubber  Plantation,  South  India,  tapping  by  the 
V  method,  it  was  found  that  morning  tapping  gave  much  better 
results  than  evening  tapping.  The  figures  for  the  whole  season 
show  the  average  quantity  of  latex  per  incision,  each  6  inches  in 
length,  obtained  in  the  morning  to  be  354  c.c.  compared  with 
r8g  c.c.  in  the  evening.  Tapping  in  the  rains  was  found  to  give 
almost  double  the  amount  of  latex  per  incision,  namely,  6'62  c.c, 
but  the  yield  of  dry  rubber  per  1,000  c.c.  of  latex  was  much  less, 
being  12-8  oz.  as  compared  with  16-4  oz.  from  morning  tapping 
and  15-1  oz.  from  evening  tapping  before  the  rains.  The  best 
season  for  tapping  was  found  to  be  from  October  to  February. 

Compass  Tapping. 

Several  experiments  have  been  carried  out  with  the  object  of 
proving  which  is  the  best  part  of  the  tree  to  tap  during  morning 
and  evening.  It  would  appear  that  the  tapping  areas  of  the  trees 
can  be  conveniently  divided  into  four  parts  :  one  side  to  face 
north,  the  next  south,  and  the  other  two  east  and  west  respectively. 
Each  side  can  be  tapped  on  a  definite  system,  say  once  per  day, 
twice  per  week,  and  so  on.  When  the  east  side  has  to  be  tapped 
it  is  best  to  perform  the  operation  in  the  afternoon  or  evening,  and 
to  tap  the  west  side  during  the  early  part  of  the  day  ;  such  a 
method,  applicable  to  the  east  and  west  sides  of  the  tree,  prevents 
direct  exposure  of  the  tapping  area  to  the  sun's  rays  during  work- 
ing operations,  and  allows  the  flow  of  latex  to  continue  for  a 
sHghtly  longer  period  of  time. 

Frequency  of  Tapping. 

The  frequency  of  tapping  varies  considerably,  but  it  is  by  no 
means  clearly  proved  that  the  tree  will  not  stand  tapping  every 
alternate  day  throughout  the  greater  part  of  the  year.  The  fact 
that  an  interval  of  one  day  is  sufficient  for  the  wound  response  to 
become  obvious  is  of  interest  and  importance. 

It  is  perhaps  not  advisable  to  judge  the  effect  of  very  frequent 
tapping  from  the  results  obtained  in  the  Amazon  districts,  as  there 
the  trees  are  usually  very  old,  and  in  many  cases  have  never  been 
tapped  before.  Nevertheless,  it  is  of  interest  to  learn  that  in  those 
districts  Hevea  is  often  tapped  for  180  days  each  year  without 
apparently  doing  very  serious  damage  to  the  trees. 

In  Ceylon  tapping  every  day  throughout  alternate  months,  or 
every  day  when  moisture  is  abundant,  or  on  alternate  days  through- 


PARA    RUBBER  235 

-out  the  year,  has  given  good  yields.      Available  returns  show  that 
alternate-day  tapping  is  almost  the  rule  on  Ceylon  estates. 

Experiments  in  Ceylon  on  Frequency. 

The  following  results  of  experiments  at  Henaratgoda  are  of 
value,  as  they  show  what  yields  have  been  obtained  by  tapping 
trees  of  similar  age  at  varying  intervals.  The  tapping  operations 
were  commenced  in  September,  1905,  and  ended  in  February, 
1906,  the  full-spiral  system  being  adopted  in  all  cases  quoted  below, 
from  the  base  to  a  height  of  five  to  six  feet. 

These  results  suggest  that  the  average  amount  of  rubber 
obtainable  per  tapping  operation  is  hkely  to  increase  when  an  inter- 
val of  one  or  more  days  is  allowed  between  successive  operations. 
They  also  indicate  that  the  average  yield,  per  tapping,  is  better 
when  the  trees  are  tapped  every  alternate  day  than  when  tapped 
once  per  day  or  once  per  week.  At  Singapore  the  yields  obtained 
by  tapping  every  day  were  better  than  those  secured  by  tapping 
•every  alternate  day.  From  a  practical  standpoint,  however,  the 
total  quantity  of  rubber  obtainable  when  the  trees  are  judiciously 
tapped  at  regular  intervals  is  of  more  importance  than  the  deduc- 
tions just  made  ;  the  latter  must  not  be  construed  as  contradicting 
the  accepted  theory  of  wound  response  discussed  elsewhere. 

Yield  of  Rub- 
Yield  of  Dry  ber  per  tap- 
Frequency  of           Number  of      Number  of     Rubber  per  ping,  per 
"     Tapping.          Times  tapped.       Trees.           five  trees.  five  trees. 

lb.  oz.  oz. 

Every  day  . .           . .        i68                    5                    42       7I  40 

Every  alternate  day        83                   5                   49       7I  9'5 

Twice  per  week     ■  •         57                 25                   14       o  4'o 

Once  per  week       . .         28                   5                   12       gj  7^7 

Once  per  month    . .           7                   5                     o     15!  2-1 

The  following  table  shows  the  results  obtained  in  Ceylon  by 
tapping  trees  at  different  periods  during  eleven  months  :— 

Frequency  of  Number  of  times     Number  of     Yield  of  dry  rub- 

tapping,  tapped.  trees.  ber  per  tree. 


Every  day 
Every  alternate  day 
Twice  per  week 
Once  per  week  . . 
Once  per  month 


lb.     oz. 

270  5  no 

136  5  12       8 

91  25  28 

44  5  3     13 

II  5  o     ic 


Alternate  and  Daily  Tapping  in   Malaya. 

Tapping  every  alternate  day  or  every  day  appear  to  be  the 
two  frequencies  adopted  in  Malaya.  Some  records  show  a  better 
yield  from  tapping  every  alternate  day,  others  show  very  little 
difference  over  a  period  of  many  months.  Campbell  (Malay 
Mail,  May  3rd,  1910)  stated  that  as  a  result  of  numerous  experi- 
ments he  had  found  that  over  a  period  of  six  months  tapping  on 


236  PARA    RUBBER 

alternate  days  gave  the  best  results  in  the  first  three  months,  but 
during  the  second  three  months  tapping  every  day  gave  the  bigger 
yield.  An  independent  authority,  after  carr5nng  out  a  lengthy 
research  in  Malay,  states  that  in  his  opinion  the  alternate  day 
system  is  better  for  a  variety  of  reasons, 

Frequency  Experiments  at  Buitenzorg. 

Haas,  in  his  account  of  the  experiments  in  Java  (I.R.J., 
July  8th,  191 1),  stated  that  experiments  were  conducted  on  trees 
planted  in  1904-5,  and  all  the  trees  tapped  had  a  minimum  circum- 
ference of  18  in.,  3  ft.  above  the  soil.  The  results  were  based  on 
one  square  metre  of  tapping  surface,  and  showed  that  the  largest 
quantity  of  rubber  was  collected  from  those  trees  which  were 
tapped  every  day.  He  thought,  however,  the  experiment  should 
be  conducted  over  a  longer  time  before  any  decisive  result  could  be 
obtained. 

Tapping  Frequency  and  Composition  of  Latex. 

Clayton  Beadle  and  Stevens  (LR.  J.,  January  28th,  1911),  have 
determined  the  composition  of  latex  got  by  tapping  trees  of  a 
known  age  every  alternate  day.  They  state  that  ' '  the  percentage 
of  total  solids  and  caoutchouc  depends  on  the  manner  and  fre- 
quency of  tapping.  For  trees  of  an  average  age  of  seven  or  eight 
years,  lightly  tapped  every  other  day,  the  total  dry  solids  were 
found  to  be  about  40  per  cent.  The  specific  gravity  varied  from 
0-980  to  0-972.  In  another  series  of  experiments  where  the  same 
trees  were  more  heavily  tapped,  the  total  dry  solids  were  approxi- 
mately 30  per  cent.  The  total  solids  in  the  latex,  other  than 
caoutchouc,  amount  to  about  2^  per  cent,  on  the  latex,  so  that 
by  subtracting  2-5  from  the  figure  for  total  dry  solids,  we  obtain 
the  approximate  figure  for  caoutchouc.  Of  the  samples  examined, 
the  highest  figure  for  caoutchouc  was  43  per  cent.,  and  the  lowest 
18-5  per  cent. " 

Wound  Response. 

It  has  been  stated  that  native  collectors  of  Hevea  rubber  do 
not  attempt  to  gather  the  latex  from  the  first  incisions,  and  that  a 
quantity  capable  of  being  collected  is  only  obtained  after  two  or 
more  tappings  in  approximately  the  same  area.  It  is  certain!}-  not 
advisable  to  make  the  first  incision  so  deep  that  a  good  flow  of  latex 
is  obtained  at  once  ;  only  small  quantities  of  latex  should  be 
expected  from  the  original  incisions.  The  first  cuts  can  be 
deepened  as  necessity  determines  in  subsequent  tapping  operations. 
The  flow  to  the  injured  part  increases  gradually,  and  may  reach 
the  maximum  after  three  to  fourteen  tappings,  after  which  it 
dechnes  if  the  wound  area  is  continuously  tapped.  The  first 
reliable  results  were  obtained  in  Ceylon,  and  as  the  ' '  wound 
response ' '  is  now  recognized  as  one  of  the  most  important  principles 
in  determining  the  frequency  of  tapping,  the  following  digest  of 
Parkin's  results  is  given  : — 


PARA     RUBBER 


237 


Number  of 

Number  of 

Date  of 

Yield  of 

Tappings. 

Incisions. 

Tapping. 

Latex  in  c.c 

ist  tapping 

40 

March  25 

610 

2nd     ,, 

40 

„       30 

105-5 

3rd      „ 

40 

April      6 

2200 

4th     ,, 

40 

12 

2085 

5th     „ 

40 

,.       15 

255-5 

6th     ,, 

40 

20 

290-0 

7th     „ 

40 

,.       25 

276-0 

8th     ., 

40 

May       I 

2530 

9th 

40 

6 

264-5 

loth      ,, 

40 

„       13 

275-0 

nth      ,, 

40 

20 

255-0 

I2th     ,, 

40 

..       26 

262-0 

13th     ,, 

40 

June      I 

328-0 

14th     „ 

40 

6 

449-0 

The  increase  in  yield  from  61  to  449  c.c.  of  latex  by  repetitional 
tapping  in  approximately  the  same  area  is  little  less  than  wonderful, 
and  it  now  remains  to  determine  the  interval  which  must  be 
allowed  between  successive  tappings.  Recent  experiments  in 
Ceylon  do  not  show  the  same  large  increase  as  that  originally 
obtained  by  Parkin.  The  wound  response  is  not  evident  twelve 
hours  after  tapping,  but  within  twenty-four  to  forty-eight  hours 
it  is  decidedly  obvious.  In  these  results  it  will  be  observed  that 
the  quantities  of  rubber  in  the  increased  yields  of  latex  are  not 
given.  This  point  has  been  cleared  up  in  some  recent  Ceylon 
experiments. 

These  results  suggest  the  advisability  of  every  planter  carrying 
out  his  own  experiments  to  determine  whether  it  is  better  to  tap 
every  day  for  the  half  of  each  month,  alternate  days  during  each 
month,  or  only  during  certain  months.  Tapping  every  day, 
either  for  the  whole  of  the  months  when  rain  was  abundant  or 
only  during  alternate  months,  has  already  given  excellent  results 
on  a  large  scale  on  several  estates  in  Ceylon.  The  nature  of  the 
origin  of  the  latex  tubes  in  Hevea  brasiliensis  accounts,  to  some 
extent,  for  the  variation  in  yields  from  the  same  area.  The  tubes 
require  a  certain  time  to  complete  their  formation,  and  for  this 
reason  areas  which  do  not  yield  any  latex  on  particular  days  may 
give  abundant  flows  subsequently,  when  the  processes  of  perfora- 
tion and  decomposition  are  sufficiently  advanced. 

Wound     Response    in    Singapore. 

Ridley  (Straits  Bulletin,  July,  1910)  states  that  the  increase 
in  latex  begins  between  the  fifth  and  tenth  tappings,  and  is 
accompanied  by  a  fall  in  the  percentage  of  rubber  in  the  latex, 
though  this  is  more  than  made  up  by  the  increase  in  quantity  of 
the  latex.  He  notes  that  in  the  case  of  some  trees  tapped  daily 
and  on  alternate  days  at  different  periods,  the  increase  in  the  latex 
began  in  both  series  of  tappings  after  the  sixth  tapping,  and  yet  this 
was  after  six  days  in  one  and  twelve  in  the  other.  The  increase 
in  latex  is  usually  exhibited  in  the  second  and  subsequent  periods 
of  tappings  after  fewer  tappings  than  in  the  first  period.  Ridley 
noted"  a  change  in  the  colour  of  the  latex  from  yellow  to  white; 


238  PARA     RUBBER 

this  is,  according  to  him,  comparable  with  the  alteration  in  colour 
at  seasons  of  heavy  rainfall,  due  to  excessive  water  in  the  latex. 

Wound    Response   in    Java   and   Trinidad. 

In  Java,  Haas  has  proved  that  wound  response  occurs  in  the 
Hevea  trees  in  that  island.  He  also  points  out  that  an  increase  in 
the  number  of  incisions  increases  the  yield  of  rubber,  but  not  in 
the  same  proportion,  and  states  that  an  increase  of  25  grammes  of 
rubber  per  square  metre  of  tapped  surface  is  only  obtained  after 
more  than  doubling  the  number  of  incisions. 

Hart  (\\M.  Bull.,  1907),  observed  that  a  second  and  even 
third  How  could  be  obtained  from  the  same  cuts  if  the  rubber  were 
allowed  to  dry  for  some  hours  in  the  cut  and  were  then  removed. 
That  this  should  be  held  as  wound  response  is  a  matter  of  doubt. 

Explanation   of  Wound   Response. 

A  satisfactory  explanation  of  the  phenomenon  of  wound 
response  has  not  yet  been  propounded.  It  is  commonly  assumed 
that  the  increased  flow  of  latex  is  due  to  the  lowering  of  pressure 
in  the  area  excised  and  to  the  consequent  rush  of  water  and  other 
liquids  in  the  direction  of  least  pressure.  On  arrival  at  the 
excised  area,  the  water  and  latex  contents  find  that  the  laticifers 
opened  the  previous  day  have  been  closed  by  coagulated  substances, 
and,  consequently,  they  accumulate  in  this  area  until  the  second 
incision  is  made.  It  has  been  suggested,  but  on  what  anatomical 
evidence  it  is  not  clear,  that  during  the  development  of  wound 
response  the  cut  ends  of  the  laticifers  become  swollen  and  assume  a 
trumpet-like  form.  This  is  a  point  which  can  easily  be  settled 
by  examination  under  the  microscope.  Parkin  does  not  believe 
the  increased  flow  to  be  due  to  the  formation  of  new  laticifers,  and 
suggests  that  it  may  be  caused  by  latex  from  adjoining  areas  flowing 
into  and  refilling  the  drained  tubes. 

\^'ouND   Response  in   24  Hours. 

Arden  concluded  from  the  following  experiments  that  the 
length  of  time  which  should  elapse  before  re-opening  incisions 
need  only  be  24  hours,  and  that  tapping  every  alternate  day  instead 
of  daily  was  not  always  advisable.  The  following  were  his 
results  : — 

60  incisions  made  on  six  consecutive  days  gave    99  J  oz.  wet  rubber. 
60         ,,        at  intervals  of  two  days  ,,         iii         ,,  ,, 

60         ,,  ,,         ,,         ,,  one  week  ,,         104^ 

In  the  Peradeniya  experiments,  where  the  spiral  system  has 
been  used,  it  has  been  noticed  that  the  renewed  cortical  tissue 
becomes  more  or  less  convex  in  outhne.  In  some  instances  clots 
of  rubber  were  found  beneath  the  bulging  areas,  and  from  micro- 
scopic examination  it  was  concluded  that  the  convex  outline 
was  due,  to  some  extent,  to  the  abnormed  rapid  distension  of 
the  cells  of  the  newly-formed  tissue  ;  the  coagulated  rubber  seemed 


PARA     RUBBER  239 

to  arise  by  the  bursting  of  the  inflated  tubes.  This  was  ' '  wound 
response  "  to  a  remarkable  degree,  and  on  all  such  areas  the  use  of 
Bowman  and  Northway's  pricking  instrument  gave  abundant 
flows  of  latex. 

Recent  Ceylon  Experiments. 

A  recent  Peradeniya  Circular,  by  Bamber  and  Lock,  is  of 
interest.  The  writers  state  that  the  experiments  were  designed 
with  a  view  to  ascertaining  what  differences,  if  any,  exist  in  the 
quantity,  composition,  and  properties  of  rubber  latex  drawn  from 
the  trees  by  tappings  carried  out  at  different  intervals  of  time. 
They  were  made  upon  trees  upwards  of  twenty  years  old  at 
Henaratgoda.  Seventy  trees  were  chosen,  in  seven  rows,  such 
that  the  total  circumference  of  the  ten  trees  in  each  row  was  as 
nearly  as  possible  the  same.  The  plan  of  the  experiment  was 
to  tap  the  trees  of  the  first  row  every  day,  of  the  second  every 
second  day,  and  so  on  up  to  the  seventh,  which  was  tapped  every 
seventh  day. 

In  giving  conclusions  they  emphasise  the  fact  that  the  ex- 
periments were  carried  out  upon  trees  which  had  not  previously 
been  tapped  with  any  regularity,  and  which  were  beginning  to 
show  obvious  signs  of  the  ill  effects  of  close  planting.  The  princi- 
pal conclusions  are  as  follows  : — 

' '  Taking  the  first  40  tappings  of  each  series,  there  is  no 
sensible  difference  in  yield  which  can  be  ascribed  to  the  length 
of  the  interval  between  successive  tappings.  The  yield  from 
trees  tapped  daily  and  from,  trees  tapped  weekly  is  practically 
identical  for  the  same  number  of  tappings,  both  in  the  gross  and 
in  proportion  to  the  area  of  bark  tapped. 

' '  During  the  first  few  tappings  the  rate  of  fall  in  the  per- 
centage of  rubber  contained  in  the  latex  is  more  or  less  inversely 
proportionate  to  the  length  of  the  interval  between  successive 
tappings,  the  fall  being  more  rapid  as  the  tappings  succeed  each 
other  at  shorter  intervals.  Sooner  or  later  a  nearly  constant 
percentage  composition  of  the  latex  is  arrived  at.  This  final 
percentage  is  lower  in  the  case  of  trees  tapped  at  short  intervals 
than  in  the  case  of  trees  tapped  at  longer  intervals. 

' '  As  might  be  expected  from  the  less  concentrated  con- 
dition of  the  latex,  the  proportion  of  scrap  rubber  obtained  is 
lower  in  the  case  of  more  frequent  tappings. 

"Mature  trees  tapped  daily  for  eighteen  months  continue 
to  afford  a  profitable  yield  of  rubber.  After  yielding  over  7 
pounds  of  rubber  per  tree  in  this  period,  the  average  yield  at  the 
440th  tapping  was  at  the  rate  of  4  pounds  of  dry  rubber  per  tree 
annually.  The  general  appearance  of  the  trees  at  this  time  was 
quite  healthy,  and  they  showed  no  signs  of  having  suffered  from 
the  severe  tapping  which  they  had  undergone. 

"It  is  apparent,  therefore,  that  frequent  tappings  are  to  be 
recommended  from  a  practical  point  of  view  so  far  as  more  yield 
is  concerned,  but  the  removal  of  bark  is,  of  course,  proportionately 


240  PARA     RUBBER 

more  rapid.  On  the  quarter-system  of  tapping  this  is  of  less 
importance,  and  it  still  remains  to  be  determined  whether  it 
would  not  pay  better  to  tap  daily  "during  certain  months  and  rest 
the  trees,  or  only  tap  at  two  or  more  days'  interval  during  the 
months  when  flow  is  less. ' ' 

In  a  later  circular  (Vol.  V.,  No.  i8),  computations  are  given 
of  the  average  annual  crop,  per  acre,  and  the  rate  of  the 
exhaustion  of  the  original  bark  for  the  different  rates  of  tapping  : — 

Frequency  (days)                           I.  II.  III.  IV.  V.  VI.  VII. 

lb.  lb.  lb.  lb.  lb.  lb.         lb. 

Per  acre           885  566  480  381  364  315  257 

Bark  exhausted  in  (years)      . .       2  J  4  6  7  8  9         10 

Resting  Periods  During  Tapping. 

Apart  from  the  rest  sometimes  given  during  periods  of  leaf- 
shedding  and  fruiting,  the  question  of  refraining  from  tapping 
during  certain  months  in  the  year  has  been  considered.  Such  a 
system  will,  perhaps,  be  necessary  in  the  event  of  labour  being 
inadequate  to  tap  each  tree  every  alternate  day.  In  parts  of 
Bolivia  the  trees  are  tapped  during  a  period  of  two  years,  and 
are  then  rested  for  a  similar  period.  Other  rubber  trees  are 
tapped  for  six  years  at  a  time  and  then  left  untouched  for  a  like 
term. 

In  the  report  of  the  Director  of  Agriculture  for  Malay,  1908, 
reference  is  made  to  this,  point.  On  some  estates,  after  a  period 
of  some  weeks  or  months  of  tapping, '  a  period  of  about  equal 
length  is  allowed  to  elapse  without  tapping.  On  others,  and  the 
majority  of  places,  tapping  is  continued  without  cessation,  in 
some  cases  trees  having  without  any  reduction  of  yield  been 
tapped  for  3^  to  4  years  every  other  day  without  cessation. 

Carefully  kept  data  on  some  Malayan  estates  show  that  after  a 
period  of  some  three  months  alternate  days'  tapping,  the  amount 
of  latex  per  tree  decreases  to  an  amount  which  is  of  less  value  than 
the  cost  of  tapping,  but  after  a  rest  of  two  months  the  trees  again 
on  the  fourth  or  fifth  tapping  yield  the  maximum,  which,  after 
some  forty  tappings,  begin  to  rapidly  decrease.  The  reverse  of 
these  observations  is  to  be  found  on  other  estates  where  accurate 
figures  of  yields  show  that  after  continuous  tapping  for  some  two 
or  three  years,  the  amount  obtained  varies  only  slightly,  never 
steadily  decreasing.  The  variation  is  caused  by  climatic  condi- 
tions, short  periods  of  little  or  no  rainfall  reducing  the  yield,  and 
periods  of  excessive  rainfall  producing  somewhat  the  same  results. 

It  is  easy  for  the  planters  to  determine  when  the  yield  of 
latex  of  rubber  is  showing  a  serious  decline,  and  to  modify  accord- 
ingly the  tapping  system. 

Fitting  (page  47,  Enghsh  trans.)  beheves  in  resting  periods, 
and  suggests  that  it  would  be  advantageous  to  tap  for  two  or  three 
months,  then  rest  for  one  or  two  months,  and  subsequently 
re-commence  tapping.  He  further  recommends  that  when  the 
first  tapping  period  is  over,  the  trees  should  be  rested  for  five  to 
six  months.     He  does  not,  however,  indicate  the  difficulty  of 


PARA     RUBBER  241 

organising  the  labour  force  to  carry  out  work  on   these  Hnes, 
neither  does  he  prove  the  necessity  for  such  long  intervals. 

Tapping  Frequency  and  Bark  Renewal  in  Malay. 

It  is  obvious  that  the  interval  of  tinae  to  be  allowed  before 
renewed  bark  is  tapped  will  largely  depend  upon  the  depth  to 
which  the  bark  has  been  previously  cut  and  also  upon  the  rate  of 
growth  of  the  trees.  Gallagher  advocates  a  four-year-interval 
if  the  trees  are  planted  closer  than  24  by  24  feet ;  at  this  or  a 
wider  distance  he  suggests  three  years.  Parkinson  is  reported  to 
have  declared  that  he  considered  two  years  as  ample  for  bark 
renewal  after  the  first  tapping  and  three  years  thereafter.  It  is 
quite  clear  that  most  of  the  authorities  quoted  have  been  influenced, 
in  advocating  short  periods  for  bark  renewal,  by  the  rapidity  with 
which  bark  has  been  formed  after  the  first  or  second  cortical 
stripping.  They  do  not  appear  to  have  considered  that  renewed 
bark  cannot  always  be  tapped  as  economically  as  the  original, 
neither  have  they  appreciated  the  fact  that  in  the  first  few  years 
■  the  tree  usually  grows  at  its  maximum  rate  on  plantations.  In 
future  years,  when  trees  are  older  and  bark  renewal  is  slower,  the  bad 
effect  of  rapid  cortical  stripping  will  assuredly  be  manifest. 

Rate   of  Bark  Renewal  in   Ceylon. 

The  rate  at  which  the  bark  of  tapped  trees  is  renewed  varies 
considerably.  Generally  the  renewed  bark  forms  at  the  most 
rapid  rate  on  trees  grown  alone  and  at  a  wide  distance  from  each 
other.  It  renews  very  slowly  on  closely-planted  trees,  and  on  those 
which  have  been  planted  in  poor  soil  or  where  associated  with 
intercrops.  The  bark  does  not  renew  quickly  when  the  root 
growth  of  the  trees  is  checked  by  the  roots  of  other  plants,  and 
some  surprising  results  may  yet  be  recorded  from  estates  with 
crowded  mixed  products. 

On  young  trees  the  renewed  bark  is  often  bulging  and  convex 
in  outline,  and  within  a  few  months  may  attain  the  same  thick- 
ness as  the  primary  untapped  bark.  On  older  trees  which  have 
been  deeply  pared,  a  longer  interval  is  required  for  the  renewed 
bark  to  grow  to  the  same  thickness  as  the  untapped  areas.  Thick- 
ness of  renewed  bark  is,  however,  not  the  only  criterion  of  maturity; 
often  the  cells  in  renewed  bark  are  equal  only  in  size,  and  not  in 
contents,  to  those  of  the  primary  bark. 

Measurements  made  in  April,  1908,  showed  that  on  Gikiyana- 
kanda  estate,  the  renewed  bark,  on  a  nine-year-old  tree  grown  on 
poor  soil,  was  when  three  years  old,  ^^  to  j-^  of  an  inch  in 
thickness. 

The  following  measurements  were  also  made  on  an  estate  in 
the  South  of  Ceylon,  in  April,  1908  : — 


Age  of 

Thickness 

Height  from 

renewed 

of  renewed 

ground  of 

bark. 

bark. 

point  of 
measurement. 

Second  renewed  bark . . 

2  months 

1  inch 

Base 

Second  renewed  bark . . 

15 

4    .. 

5 J  feet 

First  renewed  bark     . . 

..       36       .. 

1    .. 

5    feet 

242  PARA    RUBBER 

These  measurements  were  made  on  a  tree,  14  years  old,  with 
a  girth  of  71  inches  a  yard  from  the  ground.  The  reinnants  of 
primary  bark  above  the  tapping  area  had  an  average  thickness  of 
about  I",  so  that  the  renewed  bark  three  years  old  appeared  to  be 
equal  to  the  original.     The  tree  has  given  15  lb.  of  rubber  in  4  years. 

Another  tree  4J  years  old,  had  its  renewed  bark  y\"  in  thick- 
ness though  only  two  months  old  ;  this  was  nearly  equal  to  the 
thickness  of  the  primary  bark  above  the  tapping  area. 

The  old  Henaratgoda  trees,  measuring  68,  56,  29,  and  18 
inches  a  yard  from  the  ground,  had  renewed  bark  about  two  years 
old  measuring  f,  |,  |,  and  f,  of  an  inch  respectively,  in  thickness. 

The  bark  renews  fairly  rapidly  on  the  majority  of  the  trees, 
but  the  latex  takes  longer  to  mature. 

When  to  Tap  Renewed  Bark. 

There   have   been   several   attempts   to   reduce   the  interval 
between  removing  one  bark  and  tapping  its  successor,  which,  in 
1908,  I  suggested  should  be  a  minimum  of  three  to  four  years. 
Carruthers,   who  was  perhaps  under  the  misapprehension  that 
my  deductions  were  based  on  Ceylon  only,  argued  thus  :    ' '  The 
time  of  four  years  has  been  arbitrarily  fixed,  and  tapping  schemes 
are  arranged  in  relation  to  that  period.     That  four  years,  three 
years,  or  two  years  are  necessary  for  the  formation  of  bark  suitable 
for  tapping  cannot  yet  be  definitely  stated,  but  it  is  highly  probable 
from  isolated  cases  where  such  experiments  have  been  made  that 
four  years  is  unnecessarily  long.     Experimental  work  and  observa- 
tions on  tapping  and  yield  of  rubber  made  in  Ceylon  are  unfortun- 
ately of  little  value  for  Malaya.     The  climate  of  Ceylon  rubber 
districts,  with  its  periods  of  dry  weather,  is  not  comparable  with 
the  condition  in  Malaya,  where  rubber  trees  are  in  active  growth 
of  root,  leaf  and  other  tissues  practically  every  day  of  the  year, 
and  where,  even  when  they  are  leafless,  the  growth   of    trees  is 
not  entirely  stopped. ' '     While  I  admit  that  growth  is  slower  in 
Ceylon  and  other  countries  where  the  soil  is  inferior,  and  the  rubber 
trees  are  planted  among  other  trees  and  shrubs,  this  only  shows 
the  necessity,  to  my  mind,  for  a  still  longer  interval  to  be  cQlowed 
before  renewed  bark  is  tapped.     It  is  better  to  remove  too  little 
than  too  much  bark,  especially  in  view  of  the  fact  that,  with  a  few 
exceptions,  only  two — or  at  the  most  three — generations  of  bark 
viz.,  primary,   secondary  and  tertiary — have  so  far  been  dealt 
with  on  Eastern  estates.     I  am  not  at  all  sanguine  that  Hevea 
trees,  even  in  Malaya,  are  going  to  present  a  heedthy  spectacle 
ten  years  hence  if  cortical  stripping  is  permitted  once  every  four 
years.     It  cannot  be  too  strongly  impressed  on  all  planters  and 
proprietors  that  the  repeated  removal  of  the  bark  always  injures 
or  weakens  the  tree,  that  few  tropical  trees  have  survived  such 
treatment,  and  that  the  growing  layer  (cambium)  is  invariably 
damaged,  sooner  or  later.   Only  on  one  occasion  (T.A.,  June,  1909) 
have  I  noticed  a  futile  attempt  to  persuade  planters  that  it  may 
not  be  necessary  to  preserve  bark. 


CHAPTER    XIII. 


HOW    NOTABLE    ESTATES    ARE   BEING    TAPPED, 

Having  described  how,  where  and  when  Hevea  trees  are 
tapped  in  various  parts  of  the  tropics,  it  will  now  be  of  interest 
to  give  some  idea  of  the  practices  adopted  on  well-known  estates 
in  the  East. 

Early  in  191 1  I  submitted  blank  forms  to  managers  of  rubber 
estates  in  the  middle  East,  in  which  were  set  out  certain  questions 
relating  to  tapping  methods  and  tapping  knives.  It  has  been 
impossible  to  use  all  the  results  obtained,  but  suf&cient  has  been 
compiled  to  indicate  the  beliefs  of  planters  in  the  various  countries. 

How  Malayan  Estates  are  Being  Tapped. 

The  following  table  will  serve  to  show  tapping  practices  on 
3ome  of  the  oldest,  as  well  as  on  the  youngest,  estates  in  Malaya  : — 


System  of  Tapping. 

Trees  3-5      Older 

years.        Trees. 


Batu  Caves     Basal  Y 


Glenshiel 


Basal  V 

&half 

spiral 

Full 
H.B. 


Seafield 

Bukit  Rajah       — 

Chersonese      Basal  Y 

Jeram 


Full 
H.B. 


Full 
H.B, 

Half 
H.B. 

Half 
H.B. 


.      Halt  — 

H.B.  opp. 
quarters 
Labu  . .  1-2  single     Half 

cuts  opp.     H.B., 
quarters  2-3  cuts 

Banteng     . .     i  or  2     Multiple 

V's  V's 

Sungei  Krian  Basal  Y 


Distance 
between 
opening 
cuts 
Inches. 

12 

lasts  li 
years 

17 


I2-I» 

12-15 

18 


Number  of  Cuts 
Frequency  to   Inch.  Tapping 

of  Including   Ordin-  knife 

Tapping,        Opening       ary  Preferred. 

Cut.       Paring. 


Alternate      15 


Daily 


15-18  Double  edged 
farrier's  knife 


20-30  Farrier's  knife 


Alternate    15-1 
Alternate      — 
Daily  16-22 


>5i- 
i8i 


'^-"wry-neck- 
ed  gouge. 


Half 
H.B. 


18 
15 


Single       and 
double  jebong 

Alternate       15      20-25  J"bent  gouge. 


Alternate   20-25      25    Farrier's  knif 


Bujang 


Basal  V 


Batak  Rabit  Basal  Y 
Rubana     , .  Basal  Y 


Alternate 
Daily 
Daily 

Daily 
Daily 


35 
15 


20     Jebong. 
42    Pull  &  push. 


17  Double  jebong 
or  straight 
gouge. 

20-22  26-28  Jebong. 

26         30   Farrier's  knife 


244 


PARA     RUBBER 


Distance 


System  of  Tapping. 

between 

opening 

Trees  3-5 

Older 

cuts. 

years. 

Trees. 

Inches. 

Nova  Scotia 

Estate    .. 

Basal  Y 

Basal  Y 

12 

Gedong 

Estate    . . 

Basal  Y 

&  then 

halfH.B.. 

2  cuts, 
opp.  qrs. 

15-18 

Bagan  Serai 

Do. 

— 

15-18 

Batu  Tiga 

Half 

Half 

15.  i° 

H.B.  opp. 

H.B. 

young 

qrs.  3 

opp.  qrs. 

18 

cuts. 

Klabang     . , 

,    Single 

Half 

16 

lines  on 

H.B. 

quarters 

Bradwall   .. 

,    Single 



12     for 

lines,  half 

10 

H.B.  on 

months' 

quarters 

tapping 

Klanang     . 

.  Basal  Y, 

Half 

Yand 

or  full 

H.B. 

H.B.. 

H.B.  with 

18  ;i 

2  or  3  cuts 

H.B., 
12 

Sungei 

Bahru     . 

.      Half 

Half 

12 

spiral  & 

H.B. 

,  basal  V. 

Sempab 

Basal  V 

Half 
H.B. 

15 

Pendamaran 

Estate    .. 

Double 
or  treble 

V.  over 
half  tree 

18 

Bukit  Lin- 

tahg      . 

.   Basal  V 

Half 

Vs.,  16, 

H.B. 

iH.B. 
12 

Batu  Unjor 

Estate    . . 

Half 

Half 

Half 

spiral 

H.B. 

spiral 

opp.  qrs., 

14,  i 

&  high  & 

H.B. 

low  V's 

18 

opp.  sides 

H.  &L. 

Estate    .. 

Full  H.B.,  half, 

Young 

H.B.  opp.  qrs., 

14. 

and  half-spiral 

old,  18 

(H.B.  signifies  herring-bone. 

H,  &L 

Frequency 
of 

Tapping. 


Number  of  Cuts 

to  Inch.  Tapping 

Including  Ordin-  knife 

Opening      ary  Preferred. 

Cut.      Paring. 


Daily       16-21    20-25  Jebong. 
Daily  20-30        Pull  &  push. 


Daily  20-30        Pull  &  push. 

Alternate      20  at  most  Jebong. 


Daily  21         23     Jebong. 


Daily  25         26     Farrier     and 

Pull  &  push. 


Alternate  12-16   20-25  Estate-made 
knife  like 
Farrier's. 


Daily  15     20-30    Gouge. 


Daily         18-24  20-30  Jebong 


Alternate   26-30    30-34  Bent  gouge. 


Daily  —         —     Gouge. 


Young     Young,  Young,  Strsught  or 
trees  &      25-30     28-33    bent  gouge. 

half  old         old 

H.B.  al-    18-25     21-28 
ternate, 
V's  daily  & 
alternate 

Alternate  Young,  Young  Bent  gouge. 
30,  old     35-40. 
18-20  old  20-25 

.  Signifies  Highlands  and  Lowlands.). 


PARA     RUBBER  245 

Basal  and  Half-Herring-Bone  Systems. 

It  will  be  observed  that,  for  young  trees  3  to  5  years  old, 
the  basal  Y  is  the  most  popular  system  in  vogue,  though  several 
estates  prefer  single  tapping  lines  on  opposite  sides  of  the  tree. 
The  system  most  popular  for  older  trees  is  the  half-herring-bone. 
A  few  estates  adopt  the  full  herring-bone  system,  but  none  have 
advised  the  full-spiral  system. 

Distance  Between  Tapping  Lines  :    12  to  18  inches. 

The  distance  between  tapping  lines  depends  upon  the  thickness 
of  the  bark  shavings  and  the  time  interval  allowed  before  tapping 
renewed  bark.  The  estates  mentioned  appear  to  have  a  range  of 
from  12  to  18  inches  between  parallel  tapping  lines.  On  the  same 
estate,  it  will  be  observed,  there  is  sometimes  variation  on  this 
point. 

Frequency    of   Tapping. 

As  might  be  anticipated  from  official  results  already  published, 
and  the  rapid  growth  in  most  parts  of  Malaya,  many  managers 
prefer  daily  tapping.  There  are,  however,  quite  a  number  who 
adopt  alternate-day  tapping,  and  in  this  category  will  be  noticed 
some  prominent  companies  already  renowned  for  their  careful 
management. 

Number  of  Cuts  per  Inch. 

The  advance  made  in  tapping  operations  is  obvious  from  the 
figures  given  in  this  column.  If  we  exclude  the  original  incision, 
which  must  of  necessity  be  somewhat  wasteful,  we  find  that  the 
thickness  of  the  bark  shavings  varies  from  i-4oth  to  i-i5th  of  an 
inch.  In  old-established  companies,  where  tapping  has  been 
going  on  for  a  few  years,  the  range  is  from  i-3oth  to  i-2oth  of  an 
inch.  This  means  that  with  daily  tapping  every  inch  of  bark  will 
last  from  twenty  to  thirty  days,  and  double  those  periods  when 
alternate-day  tapping  is  adopted.  This  is  a  very  satisfactory 
result. 

Favourite  Tapping  Knives  in  Malaya. 

It  is  remarkable  that  such  fine  bark  parings  can  be  recorded 
for  a  country  which  has  never  taken  kindly  to  the  numerous 
scientific  tapping  knives  evolved  mainly  by  Ceylon  planters.  The 
gouge,  bent  or  straight ;  the  Jebong,  single  or  double  ;  and  the 
farrier's  knife,  appear  to  be  the  principal  kinds  used  by  managers 
in  Malaya. 

How  Ceylon  Estates  are  Being  Tapped. 

A  comparison  of  the  systems  of  tapping  in  Ceylon  with  those 
in  Malaya  will  be  almost  as  instructive  as  that  of  yields  in  both 
areas  : — 

Di-stance  Number  of  Cuts 

ttCTixi;              System  of  Tapping,     between  frequency          per  Inch.             Tapping 

ESTATE.                                                    x,™T^»  °i         Including  ruj;-,™       Kmfe 

Trees  3-5       Older        ^apprng  y^^pi^g,     opening   '^^   Preferred. 

Years.        Trees.          '-""'•  Cut.         *'a™'S- 
Grand 

Central  . .     Single    Fittings'      15  Alternate      20         25      Ordinary 

lines      system  gouge. 


246 


PARA     RUBBER 


nistanri.  Number  of  Cuts 

System  of  Tapping,      b^t^en      Frequency  jper  Inch.  Tapping 


ESTATE. 

Trees  3-5 
Years. 

Older 
Trees. 

Detween            ^'t 
"iE"        Tapping. 

Including   (VHjnarv    „  ^"'^ 
OP^f°e    ^^    Preferred. 

Dimbula 

Valley    .. 

Inverted 
V    and 
half- 
spiral 

Half- 
spital 

15 

Alternate 

15 

Sculfer. 

Rayigam   . . 

Half  H.B 

.  on  one- 

18 

Alternate 

Average 

Barrydo.  with 

third  sections 

ist  six 

about  20 

Northway's 

months. 

improved   for 

Daily  at 

ist  cuts. 

height  of 

flow. 

Narthupana 

Estate    . . 

Half -spiral 

18 

Alternate 

18-20   20-25 

Ordinary 

gouge          or 

Michie-Gol- 

ledge  chisel. 

Geragama 

Estate    .. 

Single 

lines    on 

thirds 

Full 
H.B. 

15 

Every 
3rd  day 

12-14    16-18 

Barrydo. 

PelmaduUa 

Estate  .. 

Half- 
spiral 

— 

18 

Alternate 

18         22 

Sculfer. 

Lochnagar. . 

Basal  Y 

Half 
H.B. 

18 

Alternate 

Works  out  at 

7 

Barrydo. 

Anonymous 

2  cuts, 

3  cuts, 

12  &  Alternate 

16-22 

Sculfer. 

spiral 

spiral. 

15 

on  thirds 

on  thirds 

Penrith 

Estate  . . 

3  cuts, 
half- 
spiral 

20         25 

Barrydo. 

Mahawale  . . 

2-3  cuts, 
single 

lines  on 
thirds 

Half- 
spiral 

12 

Alternate 

12  ins.  of 

bark  lasts  12- 

14  months 

Barrydo. 

Matale 

Estate     . . 

— 

Half 
H.B. 

12 

Alternate 

Z3l       3oi 

Barrydo  or 
Sculfer 

Old  Haloya 

Estate      . , 

.   Basal  Y  Full  H.B. 

18 

Daily 

i8      16-17 

Barrydo 

Beddewelle 

Estate      . 

— 

Half  H.B. 

12 

Alternate 

16         13 

Barrydo. 

Suduganga 

Estate      . 

— 

Half    Young 

Alternate 

9-10     12-14 

Barrydo  or 

H.B.  & 

18,  old 

Sculfer. 

half- 

15 

spiral 

Mudamana 

Estate      . 

.    Single 
lines 

Half 
H.B. 

12 

Alternate 

Ingoya  Es- 

tate 

.     I  cut, 
straight 

Do. 

15-18 

Varies 
through- 
out year 

Mariawatte 

Estate      . 

— 

Do. 

12 

Alternate 

PARA     RUBBER 


247 


ESTATE. 


Atgalle  Es- 
tate 


Dunedin 

Estate 


Humbus- 
walana  Es- 
tate 

Dewala- 
kande  Es- 
tate 


Distance  .Mumbei  01  Cuts 

System  ot  Tapping.      between      F™QU«"":y  PM  Ineh. 

3        Old.        -PP^..        Tap°pW'?fS    «pf ir 


Trees  3-5        Older 
Years.  Trees. 


I  aopin.; 

ivnife 

Preferred. 


2  single  Halt 
lines,  H.B. 
qis. 

Single         — 
lines 


Single         — 
lines 


18     Alternate 


18     Alternate, 
daily  in 
.  last  5 
months 


18     Alternate 


—        i  H.B.  on     12     Alternate, 


thirds 

proposed 

to   tap 

daily    iri 

Nov.  and 

Dec. 

Houpe   Es- 
tate 

—             — 

12 

Alternate 

AUuta 

Basal  Y  Half 
H.B. 
opp. 
quarters 

12 

Alternate 

Lavant 

Basal  V    Half- 

18 

Alternate 

Debatgama 

Estate      . . 
Maousava 

spiral, 
3-5  cuts. 

Quarter  spiral 

Estate      . . 

Do. 

Muwankande 

Estate      . . 

i-spiral    J-spiral 
(small        (large 
trees)        trees) 

15 


20         Barrydo. 


25 


Sculler. 


Basal  V  and  Other  Systems  Adopted. 

Young  trees  in  Ceylon  have  not,  age  for  age,  the  same  girth 
as  those  in  Malaya,  and  even  when  old,  the  rate  of  growth  of 
trees  in  Ceylon  is  comparatively  slow.  These  factors  must  be 
borne  in  mind  when  the  systems  of  tapping  are  being  considered. 
In  Ceylon  the  basal  V  or  single  lines  running  around  half  the  base 
of  the  tree  (half-spiral)  appear  to  be  favoured  for  young  trees. 
For  old  trees  the  half  and  full  herring-bone  systems  either  on  J  or  on 
opposite  quarters  of  the  tree  are  adopted.  It  would  appear  that 
the  trees  are  not  sufficiently  large  to  permit  of  quarter-section 
tapping  until  they  are  considerably  older  than  similar  girthed 
trees  in  Malaya.  The  distance  between  the  tapping  lines  varies 
from  12  to  18  inches,  and  in  this  respect  there  is  similarity  to  the 
method  adopted  in  Malaya. 


248 


PARA     RUBBER 


Frequency   of   Tapping. 

Whereas  in  Malaya  the  daily  system  appeared  to  be  favoured 
by  many  managers,  in  Ceylon  there  is  remarkable  unanimity  in  the 
preference  given  to  tapping  every  alternate  day.  This  may 
perhaps  be  correlated  with  the  rate  of  growth  of  the  trees  in 
Ceylon  and  a  longer  interval  being  necessary  for  the  accumulation 
and  concentration  of  latex  and  caoutchouc  in  tapped  areas. 

Number  of  Cuts  per  Inch. 

The  thickness  of  bark  shavings  does  not,  in  Ceylon,  come  up 
to  the  standard  in  Malaya.  An  average  thickness  of  i-25th  to 
i-20th  of  an  inch  is  evidently  considered  exceptionally  good. 
This  only  proves  that  there  is  still  much  improvement  possible. 
Perhaps  the  lower  yields  from  tapped  trees  are  capable  of  being 
associated  with  the  thicker  bark  parings. 

Complex  Tapping  Knives  Favoured  in  Ceylon. 

The  ingenuity  displayed  by  Ceylon,  planters  is  reflected  in 
the  selection  of  tapping  knives  made  by  the  various  companies 
mentioned.  The  "Barrydo"  and  "Sculfer"  knives  appear  to 
be  in  great  demand,  and  it  is  natural  that  these  should  have 
followed  the  "Bowman  and  Northway"  knives.  All  of  these 
knives  were  always  noted  for  the  economy  in  bark  effected  by 
their  use,  a  point  of  considerable  importance  where  rate  of  growth 
and  thinness  of  primary  bark  have  to  be  seriously  dealt  with. 
There  is  apparently  no  desire,  even  in  Ceylon,  to  adopt  knives 
which  are  adjustable  by  the  cooly  while  working  in  the  field. 

Tapping  Methods  in   Sumatra,   Java,  Borneo,  South  India, 

and  Samoa. 

Though  the  countries  here  considered  are  numerous,  there  is 
a  similarity  in  methods  which  is  striking. 

System  of  Tapping.      Distance  Number  of  Cuts  per 

Trees  between     Frequency  Inch.  Tapping 

3  to  5  Older         tapping  of         Including  Ordinary  Knife 

Yearn.         Trees.  lines  tapping,      opening     Paring  Preferred 

Cut. 
SUMATRA. 


Serdang 

Central   . 

.  Basal  Y       Half 

H.B.  opp. 
quarters 

12 

Alternate 

20-22 

Burgess  knife. 

Soengei 

Gerpa 

.  Basal  Y   Full  H.B. 

12 

Daily 

25          22 

Bent  gouge. 

Bandar 

Sumatra 

Basal  Y   Half  H.B. 

12 

Alternate 

23          26 

Burgess  knife. 

Bangoen 

Poerba  . 

Half        Same, 
H.B.   on   4-5  cuts, 
half     of 

tree 
2-5  cuts. 

10 

Alternate 

20-25    25-30 

Sculfer  and 
Jebong. 

Anglo-Sum- 

atra 

.       —           FuU 
H.B. 

14 

Alternate 

20-22    20-22 

Straight  and 
bent    gouge. 

PARA     RUBBER 


249 


System  of  Tapping. 

Trees 

3  to  5          Older 

Years.          Trees. 

Distance 

between 

tapping 

lines. 

Number  of  Cuts  pe? 
Frequency               Inch                      Tapping 
of           Including    Ordinary         Knife 
tapping.       opening      Paring.         Preferred. 
Cut. 

Sungei 
Roean     . 

.Basal  Y, 
on  15" 
girth 

Half 

H.B.  on 

larger 

trees 

12 

Daily 

20 

25 

Jebong 

Blankahan 

Basal  Y 

Half 
H.B. 

15 

Alternate 

24 

26 

Jebong. 

Bantardawa    Basal 
Y 

Half 
H.B. 

on  opp. 

quarters 

JAVA. 
18       Alternate 

12 

i8 

Burgess. 

BORNEO. 

Sekong 

.   Single 
lines 

Half 
H.B. 

12 

SOUTH 

Alternate 
INDIA 

22 

26 

Farrier's 
knife. 

Poonmudi 

Vanguard 
Group     . 

Fitting's 
system 

.Basal  Y 

Half 

12 

12 

Alternate 
Alternate 

22 

24 

Barrydo. 

H.B.  opp. 
quarters 
■Glenbum 

Group     .  .     Do.  Do.  12  Do.  11-16         Do. 

Hawthorne 

Group     . .     —  Do.  12  Do.        20-23    22-25     Farrier. 

SAMOA. 

Upolu  . .  Basal  Y    Multiple     12       Alternate       26         28       Rengam. 

V's 

In  these  countries  it  will  be  noted  that  in  systems  of  tapping 
the  basal  Y  or  V  are  adopted  on  young  trees,  and  the  half  or  full 
herring-bone  systems  on  older  trees.  The  quarter-section  system, 
as  in  Malaya,  also  appears  to  be  favoured. 

The  distance  between  the  tapping  lines  is  generally  12  inches, 
and  alternate  day  tapping  is  usually  adopted.  The  thickness  of 
the  bark  parings  being  from  i-30th  to  i-22nd  of  an  inch,  is 
creditable  when  one  remembers  that  tapping  has  not  been  carried 
on  for  many  years  in  these  countries. 

There  is  a  greater  variety  of  opinion  as  to  the  best  tapping 
knife,  though  there  is  an  obvious  tendency  to  use  only  those  knives 
"which  are  simple  in  construction  and  are  non-adjustable. 


CHAPTER   XIV. 

EFFECTS    OF    TAPPING. 

It  is  common  knowledge  that  many  excessive  yields  have 
been  obtained  by  completely  excising '  the  whole  of  the  bark 
from  the  base  up  to  a  height  of  6  or  15  feet,  and  it  is  natural  that 
some  questions  should  be  put  forward  as  to  the  effect  of  such 
treatment  on  the  plants. 

At  the  outset  it  must  be  recognized  that  the  great  function  of 
the  cortical  or  bark  tissues  is  to  conduct  the  elaborated  food 
materials  produced  in  the  leaves,  from  above  downwards,  to  various 
sections  of  the  growing  plant,  and  also  to  store  up,  in  certain  of  its 
cells,  a  quantity  of  food  as  reserve  material.  As  a  storehouse  and 
conducting-channel  the  bark  or  cortex  is  of  vital  importance  to  the 
plant,  and  if  it  is  removed  too  quickly  the  life  of  the  tree  may  be 
endangered.  The  internal  wood,  though  of  great  importance  to 
the  plant  in  conducting,  from  below  upwards,  the  water  and 
mineral  food  absorbed  by  the  roots,  is  less  vital  than  the  cortex, 
and  the  internal  portion  may,  to  a  certain  extent,  be  dispensed 
with  without  very  seriously  injuring  the  tree.  The  cortical  tissues 
are  dependent  for  their  rene\^al  on  the  activity  of  the  cambium — 
a  delicate  tissue  separating  the  inner  cortex  from  the  wood — 
and  in  the  natural  course  of  events  they  gradually  dry  up  near  to 
the  surface  and  peel  off  in  the  form  of  dead  bark.  The  inner  cortex, 
originally  containing  the  latex  tubes,  is  therefore  ultimately  cast  off 
as  dead  bark,  so  that  it  may  be  said  that  cortical  stripping,  in 
tapping  operations,  is  one  way  of  expediting  the  removal  of  the 
bark  tissues  and  may  be  effected  without  seriously  disturbing  the 
execution  of  the  normal  functions  of  the  plants. 

Effect  of  Repetitional  Bark   Stripping. 

It  must  be  obvious  to  every  one  that  the  stripping  of  the 
bark,  as  executed  in  tapping,  is  an  unnatural  process  and  not 
exactly  comparable  with  the  same  phenomenon  in  nature.  It 
differs  from  the  natural  process  in  so  far  that  the  cortical  cells 
are  excised  while  they  are  in  a  living  condition,  and  are  entirely 
removed  at  a  time  when  they  contain  reserve  food  intended  for 
the  use  of  the  plant.  It  also  differs  from  the  natural  process 
in  so  far  that  the  average  operator  exposes  the  inner,  more  delicate, 
and  vital  tissues  of  the  cortex  and  cambium  to  atmospheric 
influences.  Such  treatment  does  affect  the  vigour  of  the  trees, 
and  if  carried  out  too  frequently  may  hasten  the  death  of  the 
plants.  The  complete  stripping  of  the  bark,  every  year,  is  most 
dangerous.     The  writer  has  seen  many  trees  which  are  not  thriving 


PARA     RUBBER  251 

under  such  treatment ;  it  can  only  be  recommended  in  cases 
where  thinning-out  of  the  trees  is  desired.  On  many  estates 
where  thfe  parallel  spiral  tapping  lines  are  originally  distanced  twelve 
inches  apart,  the  bark  is  excised  at  the  rate  of  one  inch  per  month, 
which  means  cotnplete  stripping  in  a  year  ;  on  other  properties 
an  inch  is  made  to  last  from  two  to  four  months. 

Effect  of  Tapping  on  Plant  Reserves. 

In  1907,  at  the  Society  of  Arts,  London,  attention  was  directed 
(Rubber  Cultivation  in  the  British  Empire)  to  the  length  of 
time  which  the  primary  bark  could  be  made  to  last,  a  maximum  of 
six  years  being  given.  Emphasis  was  laid  upon  the  danger 
attendant  on  the  excising  of  the  bark  at  a  rapid  rate  when  it 
possessed  reserve  food  supplies  intended  to  be  of  use  to  the  plant. 
Rare  instances  of  trees  which  had  been  killed  by  too  frequent 
tapping  were  mentioned. 

Fitting  recommends  the  tapping  of  each  quarter-section  in 
one  year,  so  that  tapping  on  the  renewed  bark  can  be  re-commenced 
at  the  beginning  of  the  fifth  year,  thus  allowing  a  clear  interval  for 
bark  renewal  of  four  years.  But,  while  emphasizing  the  necessity 
of  a  four  years'  interval,  he  rightly  suggests  that  (p.  48,  Eng. 
trans.)  re-commencement  of  tapping  after  four  years  should  only  be 
permitted  if  an  investigation  of  the  renewed  bark  proves  that  the 
wood  and  bark  cells  have  been  refilled  with  reserve  material.  He 
recognises  what  many  others  have  not ;  viz.,  that  tapping — 
removal  of  bark — results  in  the  destruction  of  living  matter, 
and  thus  confirms  the  views  I  enunciated  in  my  Ceylon  lectures 
in  1906  (Science  of  Para  Rubber  Cultivation).  He  showed  that 
soon  after  tapping  was  commenced  starch  disappeared  from 
those  parts  of  the  bark  next  to  the  cuts — above  and  below — and 
that  time  for  its  re-formation  must  be  allowed  if  the  minimum 
injury  to  the  tree  is  aimed  at. 

Excision  and  Incision. 

If  the  area  is  excised  at  such  a  rate  that  the  whole  of  the  bark, 
at  the  base,  is  removed  in  four  years,  the  oldest  renewed  tissue, 
by  the  time  it  can  again  be  tapped,  may  be  considered  near  maturity 
and  can  be  operated  on  with  comparative  safety.  About  four 
years  is  near  the  minimum  time  required  for  the  young  plants 
to  produce  what  is  considered  mature  bark,  i.e.,  fit  for  tapping. 
The  suggestion  for  less  rapid  excising  is  made  from  a  study  of 
the  observed  effect  on*  Hevea  trees  in  Ceylon.  It  is  a  question 
whether,  in  some  cases,  it  would  not  be  better  only  to  excise  the 
bark  tissues  when  fresh  areas  are  required  for  the  use  of  the  pricking 
instrument.  It  is  very  doubtful  whether  the  paring  of  the  bark 
should  be  looked  upon  as  the  one  and  only  operation  required  to 
obtain  a  flow  of  latex  ;  it  might,  perhaps,  be  better  regarded  as  a 
means  of  facilitating  the  collection  of  the  latex  obtainable  by 
incising  and  not  excising  the  milk  tubes. 


252  PARA     RUBBER 

The  effect  of  paring  away  the  outer  bark  and  exposing  the 
internal  and  more  delicate  structures  to  atmospheric  influences  has 
in  some  cases  already  been  detrimental.  In  a  particular  case  in 
mind  the  inner  tissues  dried  up  and  peeled  off  in  flakes,  exposing 
the  whole  of  the  wood.  This  effect  is  more  noticeable  on  Ceara 
rubber  trees.but  is  also  known  to  occur  on  trees  of  Hevea  brasiliensis. 
It  has  been  suggested  that  a  covering  of  some  waterproof  material 
or  of  any  substance  which,  while  affording  protection  from  rain 
or  sun,  will  not  harbour  insects,  might  be  used  to  cover  the  tapping 
area  or  renewed  bark  when  collecting  operations  have  been  com- 
pleted. The  covering  might  be  arranged  loosely  in  the  form 
of  a  mantle  or  be  wound  round  the  oblique  excised  areas  like  an 
ordinary  ' '  puttie ' '  for  one's  legs.  This  suggestion  is  one,  however, 
not  likely  to  evoke  much  sympathy  among  practical  men. 

Pricking  and  Paring  in  Ceylon  in   1908. 

I  was  surprised  to  observe  the  frequency  with  which  trees 
were  being  pricked  on  the  occasion  of  my  visit  to  several  well- 
known  Kalutara  estates  in  April,  1908.  On  two  plantations, 
where  previously  only  the  paring  operation  was  adopted,  the 
pricking  implement  was  used  as  soon  as  the  flow  following  the 
paring  operation  had  ceased.  On  another  estate  latex  was  never 
deliberately  obtained  by  paring  ;  every  evening  the  coolies  went 
round  to  collect  the  scrap  coagulated  in  the  tapping  lines  and 
gently  used  the  paring  knife  to  remove  only  the  outer  dead  bark 
and  expose  a  new  area  below  for  the  pricker  ;  on  the  following 
morning  the  pricker  was  used  on  this  fresh  area  and  the  day's 
latex  thereby  obtained.  By  such  a  method  great  economy  in 
bark  is  effected  and  the  risks  accompanjdng  the  deep  paring  method 
are  obviated  to  a  large  extent. 

The  Northway  System. 

In  1909  Northway  invented  a  new  system  of  pricking.  This 
was  reported  upon  by  Willis,  then  Director,  Peradeniya  Gardens, 
who  gave  the  system  his  approval,  stating  that  it  was  well  suited 
to  young  trees.  The  advantages  claimed  were  :  simpHcity  in  opera- 
tion, quicker  and  earlier  returns,  and  reduced  cost.  The  system 
was  taken  up  by  many  planters,  but  adverse  criticisms  were  soon 
made.  A  reply  to  these  was  published  (T.A.,  April,  1909),  in 
which  it  was  pointed  out  that  :  The  chief  indictment  was  that 
it  encouraged  the  tapping  of  immature  trees,  and  that,  in  con- 
sequence, during  the  next  few  years  a  large  quantity  of  inferior 
or  young  rubber  would  be  sent  into  the  market  from  Ceylon.  One 
important  point  forgotten  by  some  of  the  critics  was  that  it  had 
not  been  claimed  for  the  system  that  it  increased  the  yield  of  the 
tree.  What  had  been  asserted  was  that  it  jdelded  the  same 
amount  of  rubber  in  half  the  time  and  at  half  the  cost.  For 
instance,  58  mature  trees  in  24  days,  by  the  new  process,  gave 
55  lb.  of  dry  rubber,  whereas  under  the  old  system  it  took  many 
more  days,  say,  about  55,  to  secure  that  quantity  of  rubber. 


PARA     RUBBER  253 

The  fact  that  the  bark  was  not  stripped  was,  of  course,  claimed  aS 
perhaps  the  greatest  advantage  of  the  new  process.  Under  the 
new  system  not  only  were  the  resources  of  the  tree  which  could 
be  expended  in  bark-renewal  conserved,  but  the  cambium  was 
protected  by  the  bark  remaining.  Many  objections  were  raised, 
and  the  system  has,  as  far  as  one  can  judge,  not  been  adopted 
by  planters  in  Ceylon. 

Bad   Effects    of    Pricking. 

Fitting,  while  acknowledging  that  the  use  of  this  implement 
has  noteworthy  advantages,  states  that  the  effect  of  the  teeth  of 
the  pricker  on  the  bark  is  bad.  He  found  on  microscopical  ex- 
amination of  tapped  areas  that  where  the  pricker  had  not  been 
used,  the  bark  cells  were  normal ;  but  where  used,  the  bark 
contained  many  stone-cells  where  the  teeth  of  the  pricker  had 
penetrated  to  the  cambium.  Even  when  the  cambium  had  not 
been  pricked,  the  new  bark  had  its  laticifers  irregularly  dis- 
tributed. He  concluded  that  when  the  pricker  was  used,  the 
new  bark  was  uneven  and  took  longer  to  form  ;  and  on  these 
grounds  he  advised  planters  to  abandon  pricking  implements. 
Another  observer  (T.A.,  Nov.,  1910),  states  that  the  effect  of  the 
pricker  on  the  cambium  passes  off  after  six  months. 

It  may  be  accepted  as  true  that  the  use  of  the  pricker  in  the 
past  has  led  to  the  formation  of  undesirable  pimples  or  warts  in 
the  renewed  bark.  But  the  system  cannot  be  condemned  and 
dismissed  in  this  manner.  No  one  seems  to  lay  due  stress  on  the 
fact  that  in  the  ordinary  paring  methods  wounds  are  invariably 
inflicted  ;  these  subsequently  give  rise  to  scars,  which  cannot 
be  appropriately  referred  to  as  either  warts  or  pimples  but  as 
ugly  woody  protrusions.  Even  on  the  best  managed  estates  where 
paring  only  is  adopted,  one  often  finds  large  ugly  patches  of 
renewed  bark  which  cannot  be  tapped  with  safety  for  many 
years,  and  must  therefore  be  rested.  Are  these  worse  than  the 
pimples  caused  by  pricking  ?  My  view  is  that  any  system  of 
tapping  which  minimises  the  loss  of  bark  is  deserving  of  the  very 
best  attention.  The  more  rapidly  the  bark  is  excised  the  sooner 
the  latex  stores  of  the  tree  are  depleted  ;  the  longer  the  bark  ■ 
is  allowed  to  remain  on  the  tree,  within  limits,  the  larger  should  be 
the  yield  of  rubber  therefrom.  I  do  not  think  that  the  real  value 
of  a  method  such  as  that  which  has  been  expounded  by  Northway 
can  be  determined  by  scattered  trials  over  a  period  of  a  few  months. 
Carruthers  pointed  out  that  the  prickers  so  far  used  have  been 
instruments  for  making,  not  a  puncture,  but  a  short  cut  which 
does  considerable  damage.  The  perfect  pricking  knife  has  not  yet 
been  invented. 

Furthermore,  stress  should  be  laid  on  the  fact  that  the  much- 
dreaded  but  harmless  "stone  cells"  observed  by  Fitting,  and 
elaborated  upon  by  a  few  Ceylon  enthusiasts,  often  occur  abund- 
antly in  the  primary  cortex  of  seedlings  and  in  the  untapped 
bark  of  Hevea  trees.     These  are  indicated  by  Tabor,  to  whom 


254  PARA     RUBBER 

I   am  indebted  for  the  illustrations  depicting   the  anatomy  of 
Hevea  brasUiensis. 

Effect  of  Tapping  on  the  Periodicity  of  the  Tree. 

The  treatment  meted  out  to  Hevea  rubber  trees  may  be  said 
-to  be  less  drastic  than  that  adopted  in  rapidly  excising  or  peeling 
the  bark  and  cortex  off  Cinchona  trees,  and  not  so  rigorous  as  the 
cutting  off  of  the  stems  of  cinnamon  bushes  near  the  base  in  order 
to  subsequently  secure  the  dry  peeling  bark  ;  nevertheless,  where 
latex  extraction  is  inseparable  from  rapid  cortical  stripping, 
the  processes  remind  one  of  those  adopted,  in  the  past,  on  many 
Cinchona  plantations. 

Then  what  are  the  probable  effects  on  the  trees  which  have 
been  tapped  in  this  manner  ?  It  may  be  considered  too  early  to 
form  any  definite  conclusions,  but  what  may  be  regarded  as  the 
early  effects  of  extracting  latex,  and  of  cortical  stripping,  should  be 
recorded. 

The  most  striking  effect,  even  on  estates  where  there  has  been 
but  little  excision  of  the  cortex  and  where  the  latex  has  been 
mainly  obtained  by  the  use  of  pricking  instruments,  is  that  on 
the  foliar  and  other  periodicities  of  the  plant.  Several  tropical 
trees,  even  though  they  are  growing  in  the  same  garden,  often  show 
considerable  differences  in  foliar  periodicity  ;  but  untapped  trees 
of  Hevea  brasUiensis  growing  under  approximately  the  same 
physical  conditions  do  not  generally  show  very  conspicuous 
differences,  as  the  tabulated  results,  given  elsewhere,  have  shown. 

Tapping  and  Change  in  Foliar  Periodicity. 

Tapped  tress  do,  however,  show  much  variation  ;  the  leafless 
phase  of  heavily  tapped  trees  may  be  passed  through  during 
different  months  of  the  year.  It  has  been  shown  elsewhere  that 
the  foliar  periodicity  of  endemic,  indigenous  and  even  introduced 
trees  in  Ceylon  is  mainly  determined  by  the  humidity  of  the  air  and 
soil,  the  majority  of  the  trees  passing  through  their  leafless  phases 
during  the  period  when  least  moisture  is  available.  A  change  in 
foUar  periodicity  is  coincident  with  changes  in  humidity,  and  it 
appears  quite  possible  that  the  extraction  of  latex,  involving  the 
removal  of  almost  half  its  weight  in  water  may,  from  moisture 
changes  alone,  be  partly  responsible  for  some  of  the  changes 
in  foliar  periodicity.  If  the  change  were  only  more  general,  this 
conclusion  would  be  more  justifiable.  It  is  the  constancy  in  all 
periodicities  of  some  heavily  tapped  trees  of  Hevea  brasUiensis 
which  prevents  one  from  making  a  definite  statement  on  this  point. 

The  changes  in  foliar  periodicity,  produced  by  deliberately 
mutilating  parts  of  a  tree,  are  only  too  well  known  ;  probably 
much  of  the  change  in  Hevea  brasUiensis  is  due  to  the  interruption 
in  the  work  of  the  conducting  and  store  cells  of  the  cortex,  rather 
than  the  removal  of  water  in  the  latex.  If  this  is  the  case,  the 
interruption  may  lead  to  further  irregularities,  to  a  lessening  of  the 
vigour  of  the  plant,  and  even  hastening  the  decay  or  premature 
death  of  various  parts. 


trees. 

trees. 

cm. 

cm. 

. .          X.48 

2.63 

0.62 

1.07 

[Tapping  stopped.] 

3.10 

1.98 

PARA     RUBBER  255 

Effect  of  Tapping  on   Seeds. 

Reports  have  been  frequently  received  to  the  effect  that  the 
size  and  number  of  the  seeds  produced  have  been  reduced  on  some 
tapped  trees,  and  in  particular  instances  an  increase  in  number  of 
seeds  per  tree  has  been  noted  ;  the  latter  is  probably  suggestive 
of  more  danger  than  the  former.  Some  statistics  appear  to 
indicate  that  though  the  seeds  from  tapped  trees  are  smaller, 
weigh  less  per  1,000  seeds,  are  denser  and  lose  more  weight  in 
dr3dng  than  those  from  untapped  trees,  yet  they  may  give  a 
greater  percentage  of  seedlings  and  preserve  their  power  of 
germination  longer. 

Effect   of   Tapping   upon   Growth. 

Vernet  (Journ.  d'Agr.  Trop.,  March,  1910),  made  periodical 
measurements  of  trees,  one  row  of  ten  that  had  not  been  tapped 
for  a  year  being  situated  between  two  rows  of  ten  each  that  were 
being  regularly  tapped  : — 

Average  increase  in  girth. 
Tapped  Untapped 

8th  Sept.,  1908,  to  ist  Jan.,  1909 
ist  Jan.,  1909,  to  gth  March,  1909 

9th  March,  1909,  to  2ist  July,  1909 

5.20  5.68 

In  face  of  the  small  number  of  trees  upon  which  observations 
were  made,  the  record  does  not  stand  for  much,  yet  the  result  is 
what  one  would  expect  when  the  functions  of  a  tree  are  interfered 
with. 

In  a  recent  Ceylon  circular  (No.  18,  vol.  V.)  it  is  noted  that  the 
trees  tapped  most  frequently  showed  the  greatest  increase  in  girth. 
This  is  almost  certainly  due  to  the  more  swollen  and  turgid  con- 
dition of  the  renewed  bark,  a  different  matter  from  increase  in 
growth. 

I  have  recently  had  an  opportunity  of  studying  the  growth 
of  trees,  tapped  and  not  tapped,  in  Klang,  Sumatra  and  Java. 
In  every  case  the  incremental  growth  of  the  tapped  trees  is  less 
than  that  of  untapped  trees. 

Frequent  Tapping  and  Reduction  in  Yield  of  Rubber. 
That  too  frequent  tapping  may  lower  the  yield  of  rubber 
there  can  be  no  doubt.  I  have  previously  pointed  out  that 
results  of  experiments  outhned  to  determine  quite  different 
points  have  shown  a  common  agreement,  in  so  far  that,  when 
tapping  has  been  done  too  frequently  or  too  extensively,  the  yield 
of  rubber  has  been  reduced,  and  the  bark  or  source  of  future  latex 
has  gone.  In  some  cases  the  poor  yield  from  well-developed 
trees  can  be  associated  with  the  too  rapid  excising  of  the  bark, 
and  the  sooner  one  realises  that  the  bark  is  really  the  ' '  mother  of 


256  PARA    RUBBER 

rubber,"  and  that  its  rapid  removal  means  a  reduction  in  sub- 
sequent yields,  the  better  for  all  concerned. 

One  might  at  first  conclude  that,  since  the  Hevea  trees 
rarely  ever  run  absolutely  dry,  and  most  of  them  (no  matter  how 
roughly  they  have  been  handled)  appear  to  contain  an  inexhaustible 
store  of  latex,  the  more  frequently  the  trees  are  tapped  the  larger 
the  quantity  of  rubber  obtainable.  In  one  series  of  experiments, 
which  may  or  may  not  be  exceptional,  this  idea  weis  disproved. 
The  trees  in  one  area  were  tapped  every  day  from  September,  1905, 
and  those  in  another  group  every  alternate  day  from  the  same  date. 
The  trees  which  were  tapped  every  day  (on  264  occasions)  gave 
about  9  lb.  of  dry  rubber  each,  and  all  the  original  bark  had  been 
cut  away  ;  those  trees  which  had  been  tapped  every  alternate  day 
(on  131  occasions)  gave  about  11  lb.  of  dry  rubber  each,  and  half 
of  the  original  bark  still  remained  on  the  trees. 

I  inspected  these  trees  in  April,  1908  (about  two  years  after 
the  experiments)  and  was  convinced  that  tapping  every  day  was 
extremely  dangerous  and  hkely  to  materially  affect  the  future 
life  of  the  tree. 

Tapping  at  less  frequent  intervals  did  not  only  give  a  higher 
jdeld  of  rubber  per  tree,  within  exactly  the  same  period,  but  there 
was  sufficient  original  bark  remaining  on  each  tree  to  last  for 
another  nine  months.  The  labour  expenses  were  reduced,  the 
yield  increased,  and  the  trees  less  drastically  treated  by  tapping 
every  alternate  day  instead  of  every  day.  There  is  some  ground 
for  believing  that,  when  incision  of  the  latex  tubes  is  made  more 
perfect  than  at  present,  the  interval  between  tapping  operations 
may,  with  advantage,  become  still  longer  and  yet  be  accompanied 
with  a  further  increase  in  yield  and  saving  of  labour.  In  view  of 
the  enormous  variation  in  the  yielding  capacity  of  bark,  and  the 
composition  of  the  latex  from  the  same  area,  it  would  be  unwise  to 
regard  these  results  as  being  always  possible  ;  they  are,  however, 
worthy  of  consideration  and  may  form  a  basis  for  further  research. 

Frequent  Tapping  and  Lowering  of  Quality. 

The  inferiority  of  some  samples  of  plantation  rubber  may 
be  partly  due  to  the  caoutchouc  and  other  constituents  being 
immature.  The  quality  of  rubber  from  the  same  trees  in  Ceylon 
varies  from  time  to  time.  The  rubber  from  the  first  tappings 
is  more  apt  to  become  soft  and  tacky  than  that  procured  some 
time  later  ;  that  from  the  same  trees  may,  when  obtained  during 
the  first  two  or  three  months'  tapping,  be  of  excellent  quality, 
but  after  a  time  the  quality  often  deteriorates  The  deterioration 
in  the  rubber  obtained  after  prolonged  and  repetitional  tapping  of 
primary  bark,  or  in  that  secured  from  young  renewed  bark, 
can  probably  be  accounted  for  by  the  changed  physical  and 
chemical  composition  of  the  latex.  The  latex  obtained  under 
these  circumstances  generally  contains  a  lower  percentage  of 
caoutchouc  and  other  ingredients,  and  seeing  that  in  the  renewed 
bark  a  large  proportion  of  the  constituents  have  arisen  within  a 


PARA     RUBBER  257 

brief  period  of  from  tiiree  to  four  years,  they  can  hardly  be  expected 
to  have  attained  the  same  degree  of  maturity  or  strength  as 
those  in  the  primary  bark  of  older  trees.  I  am  aware  that  many 
trees  are  first  tapped  when  orily  four  years  old,  but  even  then  the 
whole  of  the  bark  is  not  affected  until  two  or  more  years  after 
tapping  has  been  comm^enced.  In  the  Brazilian  and  African 
forests  the  trees  and  vines  are  only  tapped  during  certain  seasons, 
and  a  long  interval  is  allowed  to  elapse,  which  may  be  partly 
responsible  for  the  characters  of  the  rubber  secured. 

The  variation  in  the  characters  of  the  components  of  latex 
is  considerable,  especially  if  one  considers  different  aged  parts 
of  the  same  tree,  latex  often  being  abundant  in  the  younger  parts, 
but  so  constituted  as  to  be  uncoagulable.  The  association  of 
the  strength  of  the  final  product  with  the  frequency  of  tapping 
should  be  borne  in  mind. 

Reduction  of  Caoutchouc. 

One  of  the  most  interesting  demonstrations  in  connection 
with  Hevea  trees  is  the  decrease  in  percentage  of  caoutchouc  in 
the  latex  when  tapping  is  too  rapidly  carried  out.  The  yields 
on  which  the  hopes  of  the  future  have  been  largely  based  have 
been  obtained  by  tapping  the  original  cortex.  Success  in  the 
future  depends,  however,  on  the  yields  obtainable  from  renewed 
bark,  formed  after  repeated  excision  of  the  original  and  succeeding 
tissues. 

On  some  estates  the  cortical  stripping  round  the  whole  of  the 
tree  has  been  effected  in  one  year,  and  fair  yields  have  been 
obtained  from  renewed  cortical  tissues  which  were  only  one  year 
old.  It  has  been  demonstrated,  however,  that  tapping  young 
renewed  bark  is  not  advisable.  Normal  latex  may  possess  about 
50  to  60  per  cent,  of  water,  but  that  from  renewed  bark  only  one 
year  old  may  under  certain  conditions  possess  as  much  as  90  per 
cent,  of  water  and  very  little  caoutchouc. 

In  the  discussion  following  the  lecture  given  by  the  writer  at 
the  Ceylon  Rubber  Exhibition  it  was  pointed  out  that  the  per- 
centage of  the  caoutchouc  in  latex  might  vary  from  10  to  32, 
the  latex  from  trees  which  had  been  too  frequently  tapped  usuallj' 
possessing  a  very  large  proportion  of  water.  The  caoutchouc 
is  derived  from  compounds  which  have  been  identified  in  various 
parts  of  the  plant,  but  as  its  f)roduction  involves  a  complicated 
series  of  chemical  changes,  a  certain  time  interval  must  be  allowed 
for  the  accumulation  of  the  globules  and  for  a  particular  degree 
of  concentration  to  be  attained. 

Ridley,  in  his  Annual  Report  for  1906,  states  that  in  a  trial 
of  the  spiral  method  of  tapping,  he  obtained,  from  a  tree  in  the 
Singapore  Botanic  Garden,  from  the  first  period  of  tapping  531 
fluid  ounces  of  latex  giving  9  lb.  of  rubber,  and  from  the  second 
tapping,  one  month  afterwards,  433  ounces  of  latex  giving  4  lb. 
15  oz.  of  rubber. 

Recent  experiments  (T.A.,  Oct.,  1910),  in  Ceylon  indicated 
that  during  the  first  few  tappings  the  rate  of  fall  in  percentage 

Q 


258  PARA     RUBBER 

of  rubber  in  latex  was  inversely  proportional  to  the  length  of" 
interval  between  the  tappings.  Sooner  or  later  a  nearly  constant 
percentage  composition  of  the  latex  is  arrived  at  ;  this  final 
percentage  is  lower  in  the  case  of  trees  tapped  at  short  intervals. 

Effect   of   Tappixg   ix   Java. 

Dr.  Tromp  de  Haas  (Ann.  Jard.  Bot.,igio,  p.  443),  gives  an 
account  of  his  experiments  to  determine  not  only  the  effect  of 
tapping,  but  that  of  the  method  of  tapping  on  latex.  The 
experiments  were  made  on  trees  more  than  ten  years  old,  two 
systems  [a]  Holloway's  and  {h)  full  herring-bone,  being  used. 
The  following  figures  are  given  in  the  pubhshed  results  : — 


Solid  matter 

Composition  of  Solid  Matter. 

in  10  grEunmes 

Date. 

of  latex. 

Ash 

Proteins 

Caoutchouc 

Resins 

1907 

% 

% 

/o 

% 

4— IX, 

54 

1-25 

04 

900 

5-82 

6 

51 

080 

0-4 

12 

50 

080 

04 

924 

415 

18 

47 

090 

0-3 

908 

604 

26 

3-6 

100 

0-4 

907 

566 

3-X. 

3'3 

160 

07 

871 

640 

10 

2-8 

190 

06 

871 

681 

16 

33 

170 

07 

85-4 

8-24 

23 

33 

1-40 

07 

865 

7-08 

31 

3-6 

1-50 

0-7 

87-4 

559 

Tromp  de    Haas   concludes    that  ;    (i)    during   tapping,   thc- 
quantity  of  soHd  matter  in  the  latex  lessens  ;    (2)  the  proportions- 
of  ash  and  proteins  in  the  sohd  matter  increases  ;    (3)  the  method 
of  tapping  has  an  influence  upon  the  composition  of  the  latex 
This  last  conclusion  is  based  upon  the  following  table  : — 


Solid  Matter 

Composition  of  Solid  Matter. 

in  10  grammes 
of  latex. 

Ash. 

Proteins.     Caoutchouc.     Resir 

HoUoway  method 
Full  herring-bone 

grammes. 
. .       43-66 
■•        3595 

% 
II 

1-35 

0/                                          0/                                      Q, 

10                         /o                       /o 

0555                         90266                        51 
0628                         89174                        5-7 

Abnormal  Latex  from  Ceylon. 
Messrs.  Schidrowitz  and  Kaye  have  pointed  out,  in  the  ' '  India- 
Rubber  Journal"  of  July  ist.,  if 07,  that  in  a  sample  of  Hevea 
brasiliensis  latex  from  Ceylon  "the  amount  of  rubber  contained 
was  abnormally  small.  The  weight  of  the  crude  rubber  present 
in  750  cc.  of  latex,  after  pressing,  amounted  to  only  35  grams, 
of  roughly  4-6  per  cent.  Allowing  for  moisture,  this  would  meaii 
that  the  latex  in  question  contained  barely  4  per  cent,  of  dry 
rubber.  The  latex,  it  may  be  said,  was  obtained  from  the  primary 
bark  of  a  five-year-old  tree,. tapped  in  a  normal  manner,  and  we 
are  not  in  a  position  to  offer  an  explanation  of  the  exceedingly 
low  caoutchouc  contents."  They  do  not  state,  however,  what 
quantity  of  liquid  was  added  when  the  latex  was  first  bottled, 
in  Ceylon. 


PARA     RUBBER  259 

Stevens,  following  on  this  point,  states  (I.R.J.,  July  15th, 
1907),  that  he  also  has  made  "some  tests  with  separate  quantities 
of  latex  from  Ceylon,  to  which  small  quantities  of  preservatives 
had  been  added.  In  these  cases  only  small  yields  of  caoutchouc 
were  obtained. ' ' 

' '  The  latex  was  obtained  from  trees  6  and  7  years  old,  and 
represents  either  the  first  or  second  year's  tappings.  The  con- 
tents of  the  different  bottles  did  not  represent  the  same  mixture 
of  latices,  but  were  filled  up  from  different  trees  as  the  latex  came 
to  hand.  I  am  given  to  understand  that  no  water  was  at  any 
time  added  to  the  latex. ' '  The  preservatives  added  were ' '  cyllin, ' ' 
formalin,  a  salt  of  mercury,  and  chloroform,  and  the  yield  of 
moist  caoutchouc  in  separate  samples  was  8-4,  8-8,  9-2,  lo-o, 
8-6,  lo-o,  97,  and  13-5  per  cent. 

"When  allowance  is  made  for  the  moisture,  which  is  pro- 
bably not  less  than  10  per  cent.,  it  will  be  seen  that  with  one 
exception  the  yields  were  in  all  cases  less  than  10  per  cent,  reckoned 
on  the  original  latex."  In  these  instances,  the  latices  examined 
by  Messrs.  Schidrowitz,  Kaye  and  Stevens,  do  not  appear  to 
have  been  derived  from  any  specially  tapped  trees,  and  may 
indicate  the  variability  of  the  composition  of  the  latex  rather 
than  the  effect  of  excessive  tapping. 


CHAPTER     XV. 

TAPPING     AND    YIELDS     IN     THE     AMAZON     REGION. 

In  the  rational  treatment  and  tapping  of  the  trees,  the  Amazon 
has  been  decidedly  outpaced  by  the  Middle-East.  Since  the 
beginning  of  the  crude  rubber  industry  improvements  in  Amazon 
methods  have  been  few  ;  they  consist  of  little  more  than  a  lighten- 
ing of  the  head  of  the  tapping  axe,  and  the  replacing  of  the  older 
system  of  gathering  latex  in  a  gutter  at  the  base  from  numerous 
cuts  by  the  modern  cup  method.  General  adoption  of  up-to-date 
methods  cannot  be  expected,  for  each  collector  disappears  daily 
on  his  tapping  round  out  of  the  range  of  proper  supervision.  Yet 
it  must  not  be  assumed  that  chaos  rules  in  tapping  operations. 
The  main  principles  of  the  modern  system,  such  as  it  is,  are  generally 
followed,  and  tradition  with  experience  guide  all  except  the  un- 
scrupulous, or  those  beyond  any  control.  When  a  proprietor 
leases  his  concession,  he  has  to  face  the  possibility  of  tapping  being 
carried  on  in  a  fashion  that  he  resents,  but  cannot  prevent  ;  and 
even  when  he  partially  superintends  the  exploitation,  his  control 
over  the  collectors,  who  are  paid  by  results,  is  not  so  complete 
as  is  desirable. 

When    Tapping    is    Done. 

The  time  for  tapping,  in  the  Amazon  region,  is  in  the  early 
morning,  beginning  at  daybreak.  Some  reasons  for  this  are  the 
same  as  those  ruling  in  the  Middle-East ;  an  additional  advantage 
is  that  the  latex  may  be  collected  before  the  commencement  of  the 
frequently-recurring  rains  of  the  afternoon.  Interference  by 
sun  and  rain  is  sometimes  avoided  by  tapping  towards  nightfall 
and  gathering  in  the  morning.  Under  ordinary  circumstances, 
breakfast  follows  the  tapping  round,  and  after  this  interval  the 
latex  is  collected ;  immediately  after  returning  the  collector 
begins  to  smoke  the  latex.  Vice-Consul  Temple  understood  that 
tapping  ended  at  9  o'clock  ;  that  collecting  began  at  10  and 
finished  at  i  o'clock  ;  and  that  smoking  ended  at  :;  or  2.30  p.m. 
Dunleavy,  who  accompanied  a  Bolivian  collector  upon  his  round, 
stated  that  tapping  began  at  5.15  a.m.  and  ended  at  10,  that 
collecting  went  on  until  3  o'clock,  after  which  the  smoking.  Of 
course  the  time  taken  per  tree  in  tapping  varies  largely.  Cibot 
found  that  on  a  Bolivian  estrada,  fixing  from  450  to  500  cups  and 
tapping  150  trees  along  a  path  of  from  4  to  5  kilometers  (2-5  to 
3-1  miles)  long  took  from  4  to  5  hours  ;  that  is  from  i  minute,  36 
seconds,  to  2  minutes  for  each  tree.  On  a  Rio  Negro  estrada, 
according  to  Bonnechaux,  the  time  averaged  one  minute. 


PARA     RUBBER  261 

The  Tapping  Implement  and  Size  of  Cut. 

The  small-headed,  long-handled  tapping-axe  strongly  re- 
sembles a  tomahawk.  Small-headed  as  it  has  always  been,  the 
tendency  in  the  more  accessible  regions  has  been  to  lessen  its 
cutting-edge,    which   now    averages    about    one    inch    in    length. 

A  slanting  blow  is  struck  upwards  and  obliquely.  Ule  saw 
the  axe,  after  striking,  bent  outwards  to  open  the  wound  and  so 
accelerate  the  flow.  With  the  smaller  axes  the  length  of  the 
cut  seems  to  be  about  one  inch.  As  regards  the  depth  of  the  cut. 
Cross  asserted  that  it  was  about  one  inch,  and  always  went  into 
the  wood  ;  but  the  recent  practice  is  more  rational  now  that 
the  danger  of  cutting  deep  is  well  understood.  Sandmann  mentions 
a  belief  held  in  some  quarters  that  cutting  deeply  into  the  wood 
yields  more  latex.  By  Le  Cointe  it  is  stated  that  the  cuts  are 
from  5  to  10  mm.  (i-5th  to  2-5th  inches)  in  depth  ;  Warburg  also 
found  that  cuts  were  made  down  to  10  mm.,  which  he  thought  was 
too  deep.  Vice-Consul  Temple's  estimate  of  the  thickness  of  the 
bark  was  |  of  an  inch. 

Effects  of  Tapping. 

As  a  result  of  the  ill-treatment  the  trees  sometimes  receive 
the  tapping  area  may  take  on  an  abnormal  and  uneven  growth, 
large  bosses  developing.  There  is  a  photograph  extant  which 
shows  a  tree  with  its  tapping  area  about  three  times  the  diameter 
of  the  untapped  part.  Such  trees  become  unproductive  for  many 
years,  the  most  severely  inflicted  blows  failing  to  produce  latex 
except  in  very  small  quantities. 

Isolated  mention  is  made  of  attempts  to  lessen  the  dangers, 
at  the  incised  areas,  from  disease  and  insect  attack.  Some 
collectors  carry  clay  with  them  to  protect  the  more  brutallj^-made 
incisions,  or  even  to  fill  up  every  iilcision  after  the  scrap  has  been 
pulled  off.  Pearson  met  collectors  who  refused  to  pick  the  scrap  ; 
they  preferred  leaving  it  in  the  cuts  as  a  protection  to  the  wounded 
area. 

Method   of  Collecting  the   Latex. 

The  older  method  of  collecting  the  latex  is  still  followed 
in  the  more  remote  regions.  The  principle  is  to  allow  the  latex 
from  all  the  cuts,  of  which  many  are  made  at  a  time,  to  run  down 
the  bark,  previously  cleaned  and  smoothed,  into  a  sloping  guttei- 
encircling  the  whole  or  only  half  of  the  tree's  base,  and  from  this 
into  a  calabash  or  other  receptacle.  In  the  newer  method,  a  cup 
is  placed  below  each  incision.  The  cups  are  of  tin,  frequently  with 
flat  or  concave  sides  for  fitting  to  the  trunk  ;  they  seem  to  have 
supplanted  entirely,  or  nearly  so,  the  older  clay  cups,  shells  and 
bamboo  tubes.  Their  capacity  is  from  3I  to  7  fluid  ounces.  A 
common  practice,  in  fastening  the  cup  to  the  trunk,  is  to  use 
clay  as  a  cement,  and  partly  as  a  conducting  channel ;  in  some 
cases,  however,  the  edges  of  the  cups  are  pressed  into  the  bark  ; 
this  was  done  on  Eastern  plantations  a  few  years  ago. 


262  PARA     RUBBER 

Method    of   Tapping. 

The  carefully-planned  excision  methods  followed  in  the 
East  are  practically  unknown  in  Brazil.  Though  in  1872  CoUins 
mentioned  the  full  herring-bone  system,  only  isolated  and  casual 
trials  of  the  newer  or  Eastern  methods  are  heard  of.  It  is  note- 
worthy that  Dunleavy  tried  the  drastic  full-spiral  method  in 
Bolivia,  and  got  yields  largely  exceeding  those  obtained  by  the 
incision  method. 

At  each  tapping,  cuts  are  made  around  the  trunk  at  one  level, 
and  at  equal  distances  from  one  another.  A  method  probably 
rare  is  that  of  arranging  the  cuts  in  pairs  to  form  \' 's.  The  first 
ring  of  cuts  is  sometimes  made  at  the  highest  level  attainable, 
and  at  the  next  tapping  the  same  number  of  cuts  directly  below, 
and  so  on  until  the  base  is  approached.  (In  some  cases  the  first 
incisions  are  made  at  the  base  ;  in  other  instances  at  the  top  and 
bottom  simultaneously.)  Later  on,  a  second  series  is  begun  at 
the  top,  maybe  at  the  side  of  the  first  series,  or  midway  between 
the  first  and  second  rows  of  the  first  series.  These  principles 
are  followed  to  the  end  of  the  tapping  period,  and  season  after 
season,  for  so  long  as  is  possible  ;  in  course  of  time,  if  scarring 
arises,  incisions  have  to  be  made  where  a  flow  of  latex  seems 
likely  to  be  obtained. 

High  tapping  with  the  help  of  scaffolding  goes  on  when  the 
bases  of  the  trees  are  badly  scarred.  This  was  noted  in  Brazil  by 
Ule,  Sandmann,  Temple,  and  Pearson,  and  in  Peru  by  Eberhardt. 

The   Number   of  Cuts   Made. 

Among  the  numergus  accounts  of  tapping  operations  on  the 
Amazon,  there  is  not  one  that  is  complete,  and  it  is  therefore 
extremely  difficult  to  accurately  assess  the  actual  strain  imposed 
upon  the  trees.  Such  a  detail  as  the  distances  apart  of  the  cuts  at 
the  end  of  the  season  is  rarely  given,  and  the  tapping  history  season 
after  season  by  the  same  observer  is  seldom  available.  It  will  be 
noted  below  how  often  information  on  other  important  points 
is  lacking  ;  for  this  reason  alone  many  accounts  are  here  omitted, 
and  others  are  not  recorded  because  they  are  not  reliable. 

Upon  estradas  of  120  to  180  trees,  Le  Cointe  observed  that 
from  500  to  600  cups  were  needed,  each  representing  a  cut  made 
daily.  The  first  incisions  were  made  35  or  40  cm.  (14  to  16  iriche^) 
apart,  and  each  day's  incisions  were  6  cm.  (2-4  inches)  below  the 
previous  day's  cuts.  After  the  base  was  reached,  a  new  series  was 
begun  alongside  the  first  and  at  a  level  midway  between  the  first 
and  second  rings  in  the  first  series.  Six  series  might  thus  be  made, 
so  that  at  the  end  of  the  season  the  incisions  would  be  at  a  horizontal 
distance  from  one  another  of  about  2|  inches.  Sandmann  found 
that  the  first  cuts  were  44  cm.  (7^  inches)  apart,  those  of  the 
next  day's  being  5  to  7  cm.  (2  to  2|  inches)  lower.  Tapping  was 
begun  at  a  height  of  2  metres  (6^  feet),  and  the  ground  was  reached 
in  35  tapping  days,  when  a  new  series  was  begun  at  the  top  about 
two  spans  to  the  side.     He  remarks  that  some  collectors,  against 


PARA     RUBBER  263 

the  will  of  the  proprietor,  cut  three  such  series.  Other  statements 
are  still  less  complete.  Warburg  asserted  that  the  horizontal 
distance  between  the  cuts  made  each  day  was  from  10  to  20  cm. 
(4  to  7I  inches),  and  the  vertical  distance  between  the  successive 
tappings  20  to  30  cm.  {yl  to  ii|-  inches).  Witt's  estimate  of  these 
distances  was  i  to  2  feet  for  the  horizontal  and  4  inches  for  the 
vertical.  The  estimate  made  by  Cross — 4  to  5  inches  apart  and 
6  inches  vertical  distance — is  forty  j'ears  old.  It  is  clear  from  the 
above  that  where  the  horizontal  distance  is  great,  the  vertical  is 
usually  small.  Bonnechaux  claimed  that  a  vigorous  tree,  say,  50 
cm.  in  diameter  (computed  girth  about  60  inches),  bears  4  cups 
10  cm.  (nearly  4  inches)  apart,  though  there  are  rarely  more  than 
5  cups  even  when  the  diameter  is  i  metre  (girth  i2|  feet).  Clough, 
who  spent  some  years  on  the  Rio  Purus,  considered  that  a  tree  12 
inches  in  diameter  (girth  38  inches)  would  carry  6  cups.  These 
details  have  reference  to  Brazilian  practices  ;  there  are  few 
accounts  available  concerning  the  upper  waters  of  the  Amazon  in 
Bolivia  and  Peru. 

Number  of  Cuts  in  Bolivia  and  Peru. 

On  the  Rio  Beni',  in  Bolivia,  Cibot  frequently  found  a  distance 
of  40  cm.  (about  16  inches)  between  the  incisions,  the  tapping 
being  started  at  a  height  of  2-50  metres  (8  feet);  with  45  tapping 
days  before  the  base  of  the  tree  was  reached  the  vertical  distance 
must  have  been  about  2  inches.  In  180  tapping  days  four  vertical 
series  would  thus  be  carried  down  the  trunk.  During  the  second 
year  new  cuts  were  made  alongside  those  of  the  first  year.  In  the 
third  and  fourth  years  the  cuts  were,  in  level,  between  the  rings 
of  the  first  and  second  years.  Then  the  tree  was  rested  for  5  to  6 
years  to  allow  wounds  to  heal. 

The  only  information  on  this  point  regarding  Peru  is  contained 
in  such  meagre  statements  as  that  of  Eberhardt,  who  found 
trees  carrying  three  to  nine  cups,  and  recorded  that  a  new  series  of 
incisions  was  begun  each  month  at  the  top. 

Number    of    Trees    in    an    Estrada. 

The  range  in  number  of  trees  in  a  tapping  round  or  estrada  is 
considerable  ;  it  is  dependent  upon  their  spacing  and  sizes,  the 
diligence  and  dexterity  of  the  collector,  and  also  upon  whether  or 
not  the  collector  receives  any  help  in  placing  or  emptying  the  cups, 
or  in  scrapping,  from  members  of  his  family  or  others.  While 
the  number  of  trees  generally  ranges  between  50  and  200  (except 
on  the  Rio  Negro  and  iri  Bolivia,  where  the  numbers  may  be 
higher  and  the  species  other  thaMHeveahrasiliensis),  the  average  is 
probably  between  120  and  130.  Ballivian  has  drawn  a  plan  of  a 
concession  in  Peru  with  the  following  numbers  of  trees  shown  for 
each  estrada  :  103,  115,  106,  107,  100,  98,  102,  130,  120,  100,  no, 
95,  115.  98,  100,  106,  120,  108,  150,  120,  160,  120,  130,  132,  no, 
100, 105, 100, 108, 100.  An  estrada  is  arranged  so  that  the  tapping 
round  ends  near  to  the  beginning ;  there  may  be  short  paths  from  the 
raain  path  to  exploitable  trees. 


264  PARA     RUBBER 

Distances  between  the  Trees. 

Some  attempts  have  been  made  to  find  out  the  distances 
between  the  trees  in  an  estrada.  Cross  gave  an  estimate  of  from 
10  to  100  yards.  Bonnechaux  paced  the  distances  upon  a  Rio 
Negro  estrada,  and  got  an  average  of  44  paces.  In  Bohvia,  upon 
the  estradas  that  Cibot  personally  supervised,  the  mean  distance 
was  30  metres  (32-8  yards).  In  Peru,  on  the  Madre  de  Dios,  Plane 
found  an  average  of  33  metres  (36  yards)  ;  and  on  the  Vista  Alegre, 
a  branch  of  the  Madeira,  100  trees  were  stretched  along  a  path 
measuring  4,650  paces,  say  3,487  metres  (3,811  yards),  that  is,  an 
average  of  38  yards  between  the  trees. 

How  many  trees  there  are  per  acre  is  a  question  that  cannot 
be  answered  even  by  the  adoption  of  wide  limits,  very  few  esti- 
mates having  been  made  and  these  on  only  a  few  acres.  Wickham, 
who  was  in  the  Tapajos  region,  says  that  si.x  or  seven  trees,  per 
acre,  was  the  maximum  ;  he  doubts  very  much  whether  a  single 
square  mile  of  forest  exists  with  1,500  Hevea  trees  (equivalent  to 
about  five  trees  per  two  acres).  On  the  Lower  Amazon,  according 
to  Sandmann,  120  trees  occupy  4  hectares  ;  this  is  equal  to  11  trees 
per  acre.  Cibot  estimated  that  an  estrada  in  Bolivia  occupied 
from  5  to  15  hectares  (12.I  to  37  acres),  there  being  from  10  to  20 
trees  per  hectare,  or  from  4  to  6  to  the  acre. 

The  Girths  of  Tapped  Trees. 

Such  details  of  measurements  of  the  exploited  trees  as  are  at 
hand  shew  that  on  the  .Amazon  the  trees  are  generally  allowed 
to  attain  a  greater  size  before  being  tapped  than  is  the  case  in  the 
Middle-East.  Of  course,  the  reason  is  that  it  does  not  pay,  where 
trees  are  so  scattered,  to  include  young  ones  in  the  tapping  round. 
The  diameters  of  the  trees  in  an  estrada  situated  upon  a  tributary 
of  the  Rio  Negro  were  measured  by  Bonnechaux,  who  classified  the 
trees  into  groups.  The  average  girths  given  in  the  following 
table  have  been  calculated  from  the  average  diameters.  The 
height  at  which  the  measurements  were  taken  is  not  recorded  : — 


Average 

No.  of 

Average 

No.  of 

Average 

No.  of 

Average 

No.  of 

girth. 

trees. 

girth. 

trees. 

girth. 

trees. 

girth. 

trees. 

ins. 

ins. 

ins. 

ins. 

23i 

3 

49i 

38 

74i 

14 

99 

6 

31 

8 

55i 

14 

8oi 

2 

mi 

I 

37J: 

8 

62 

26 

86i 

8 

124 

I 

43i 

22 

68 

5 

93 

3 

The  lowest  of  these  calculated  average  girths  does  not  differ 
very  much  from  Cross's  estimate  of  18  or  24  inches  at  3  feet  from 
the  base  as  the  minimum  girth  for  tapping.  Sandmann  states  that 
the  average  girth  of  the  Hevea  trees  in  an  estrada  upon  the  Lower 
Amazon  was  43  inches.  The  largest  trees  recorded,  from  10  to 
12  feet  in  girth,  seem  to  have  been  those  found  by  Wickham. 
The  above  statistics  refer  to  trees  in  Brazihan  estradas. 

In  Bohvia,  Cibot  found  trees  below  0-25  metres  diameter 
(a  girth  of  31  inches)  and  as  large  as  5  metres  in  girth  (198  inches). 


PARA     RUBBER  265 

Upon  a  Peruvian  estrada,  the  diameter  of  the  trees,  according  to 
Plane,  ranged  between  20  cm.  and  1-30  metres  (equivalent  to  a 
girth  of  between  25  and  162  inches). 

The  Minimum  Age  for  Tapping. 

Various  second-hand  statements  are  available  respecting  the 
minimum  age,  in  the  Amazon  Valley,  for  tapping.  An  official 
Brazilian  publication  states  that  trees  can  be  tapped  successfully 
from  the  tenth  year,  sometimes  from  the  sixth.  From  10  to  15 
years  in  partially-cleared  forest,  and  from  25  to  30  years  in  the 
uncleared,  were  the  limits  reported  by  Pearson.  Von  Dionant 
understood  that  tapping  operations  could  be  commenced  10  years 
after  the  second  flowering  of  the  tree. 

Duration  of  the  Tapping  Season. 

In  Brazil  the  tapping  season  is  largely  determined  by  the 
rainy  season.  The  areas  close  to  the  streams  are,  in  the  rainy 
period,  submerged  and  cannot  be  exploited,  though,  where  it  is 
possible,  the  collectors  may  wade  in  waist-high.  The  heavy 
rains  may  interfere  too  much  with  the  flow  of  the  latex  and  dilute 
it  so  much  that  it  is  very  difficult  to  coagulate.  Even  the  diffi- 
culties of  transport  during  the  dry  season  encourage  periodicity 
in  tapping.  Yet,  taking  Brazil  as  a  whole,  tapping  is  going  on 
throughout  the  year,  for  the  end  and  the  beginning  of  the  season 
vary  in  different  parts  ;  April  is  given  as  the  first  month  for 
tapping  in  certain  regions  and  March  as  the  final  month  in  others. 
Over  and  above  this  it  must  be  understood  that  tapping  may 
occasionally  be  possible  in  the  rainy  season  except  in  flooded 
areas.  The  beginning  of  the  season  ranges,  according  to  the  dis- 
trict, from  April  to  September,  and  the  end  from  September  to 
March.     Its  length  is  from  5  to  9  months. 

Of  the  various  accounts  of  the  length  of  the  season  published, 
only  some  of  the  most  reliable  are  here  given.  An  official  pubhca- 
tion  records  that  the  season  lasts  from  May  to  January,  with  May 
and  September  as  the  best  period  ;  and  another  official  publica- 
tion records  it  as  lasting  from  April  to  September  in  Matto 
Grosso.  Ule  believes  that  the  season  lasts  six  months,  at  the 
most  eight  months,  beginning  in  May  or  June  and  ending  in 
January  or  February ;  leaving  out  Sundays,  saint  days,  and 
rainy  days,  about  120  working  days  remain.  Bonnechaux 
visited  the  Rio  Negro,  where  the  season  extends  from  July  to 
February,  the  number  of  tapping  days  out  of  the  200  to  250 
possible  being  100  only.  In  his  lecture  at  the  Rubber  Exhibition 
of  1908,  Witt  mentioned  that  on  the  higher  parts  of  the  river 
tapping  is  begun  in  May,  but  in  other  parts,  as  in  Amazonas,  in 
July  or  August.     The  working  days  are  from  90  to  120. 

In  Peru,  according  to  Sperber,  tapping  is  not  engaged  in 
during  the  leaf-change  from  July  to  Septernber  ;  it  is  begun  in 
October  and  lasts  until  the  end  of  December.  The  rains  from 
January  to  March  interrupt  tapping,  but  it  is  recommenced  in 
April  and  goes  oji  until  the  end  of  June. 


266  PARA     RUBBER 

In  Bolivia,  Pearson  understands  that  there  are  two  tapping 
periods  :  from  April  to  July,  and  from  October  to  March,  the  trees 
being  tapped  for  three  months  in  each  year  and  then  rested.  But 
this  is,  said  to  refer  to  the  species  producing  "mollendo"  rubber. 

Tapping  Frequency. 

Alternate-day  tapping  is  most  frequently  mentioned  in  the 
accounts  of  rubber  harvesting  on  the  Amazon  ;  the  opinion  is 
frequently  expressed  that  daily  tapping  does  not  give  pa5/ing 
yields.  The  principle  adopted  in  alternate-day  tapping  is  to 
have  one  collector  to  two  estradas  which  are  tapped  in  turn. 
Where  a  collector  works  three  estradas  in  turn — mentioned  by 
only  two  writers — more  numerous  incisions  are  made  and  therefore 
a  heavier  strain  is  imposed  upon  the  trees. 

Ule  records  that  on  the  Madeira  daily  tapping  is  carried  on, 
while  on  the  Jurua  and  Purus  two  estradas  are  tapped  alternately. 

Wound  Response  on  the  Amazon. 

After  wound  response  had  been  demonstrated  in  the  Middle- 
East,  some  Brazilians  passing  through  Singapore  informed  Ridley 
that  this  phenomenon  was  familiar  to  them.  In  his  account  of 
Brazilian  rubber-collecting,  Sandmann  states  that  every  tree 
is  first  struck  with  a  long-handled  tapping  axe  at  about  3J  metres 
(12  feet)  from  the  ground,  the  belief  being  that  this  stimulates 
the  flow  of  latex.  Two  days  later  regular  tapping  commences 
at  the  usual  height.  Two  observers  note  that  the  flow  of  latex 
from  the  first  incisions  is  small. 

Resting  of  the  Trees. 

There  are  a  few  references  to  the  practice  of  suspending 
tapping  operations  upon  a  tree  for  one  or  more  seasons.  Pearson 
records  that  trees  are  often  rested  for  a  year.  Temple  was 
informed  that  if  an  exhausted  tree  was  allowed  to  rest  for  three 
or  four  years,  it  completely  recovered  and  could  be  worked  again. 
A  writer  in  the  "  India-Rubber  Journal  "  stated  that  in  Bolivia  the 
trees  were  sometimes  tapped  for  two  years  and  then  rested  for 
the  same  period,  while  others  were  tapped  for  six  years  and 
rested  for  six.  The  statement  of  Cibot  that  in  the  same  country 
the  trees  were  tapped  for  four  years  and  rested  for  five  or  six  has 
already  been  referred  to. 

How  far  the  practice  of  resting  the  trees  is  adopted  it  is  quite 
impossible  to  learn.  It  would  appear  that  in  course  of  time  the 
tendency  is  for  the  trees  to  become  unproductive  through  the 
development  of  scars,  but  how  long  a  period  this  takes  must 
naturally  vary  greatly.  Productiveness  after  50  and  even  80 
years  of  tapping  has  been  recorded,  but  one  would  like  to  be  assured 
of  the  reliability  of  the  age  determination  before  finally  accepting 
this  statement. 


PARA     RUBBER  267 

Collection  of  the   Latex. 

There  is  not  much  to  be  gained  by  describing  the  operation 
of  collecting  latex  in  the  Amazon.  The  flow  is  said  to  end  in  from 
one  to  three  hours,  so  that  collection  may  be  begun  immediately 
after  breakfast.  The  collecting  vessels  most  favoured  at  one  time 
appear  to  have  been  calabashes  or  earthenware  vessels  suspended 
in  plaited  work  ;  tin  vessels,  including  the  ubiquitous  kerosene 
can,  are  also  now  common.  Their  capacities  range,  according  to  the 
few  records  available,  approximately  from  i  to  4  gallons.  When 
emptied,  the  collecting  cups  are  hung  upon  branches  or  sticks, 
or  are  placed  upside  down  at  the  base  of  the  tree.  A  bag  is 
sometimes  carried  for  holding  the  scrap  ;  at  other  times  the  scrap 
is  stuck  upon  the  edge  of  the  collecting  vessel. 

The  Method  of  Coagulation. 

The  method  of  coagulation  has  often  been  described.  A 
wood  fire  is  started  in  a  small  oven,  and  is  fed  in  part  with  the 
nuts  of  certain  palms,  when  these  are  available.  A  dense  smoke 
arises,  which  is  directed  to  one  point  by  placing  a  metal  cone, 
or  chatty,  open  at  both  ends,  over  the  fire.  The  latex  having  been 
poured  into  a  shallow  open  vessel,  a  paddle-like  instrument  is 
dipped  into  it  or  some  is  poured  over  with  a  dipping  can.  Excess 
of  latex  is  allowed  to  drip  off,  and  the  paddle  is  held  over  the 
smoke,  first  one  side  and  then  the  other,  two  or  three  circular 
passes  being  made  each  time.  Another  method  is  to  use  a  pole, 
one  end  of  which  is  supported  from  the  roof  or  upon  a  crosspiece, 
instead  of  the  paddle  ;  the  late.x  is  poured  over  the  middle  of  it, 
and  a  large  ball  of  rubber  is  ultimately  made.  The  formation  of 
a  ball  may  go  on  for  days.  Properly  prepared  balls  constitute 
the  ' '  fine  hard  Para ' '  of  commerce  ;  when  the  rubber  is  found,  on 
opening,  to  be  imperfectly  coagulated,  it  is  classed  as  "entre- 
fine, "  or  medium.  Scrap  rubber  taken  from  the  trees  and  from 
the  ground,  and  rubber  that  has  coagulated  in  the  cups  or  otherwise 
before  smoking,  is  dipped  into  latex  and  worked  up  into  chunks, 
forming  ' '  sernamby, "  "  coarse, "  or  "  negroheads. ' '  Newly- 
coagulated  rubber  is  very  wet,  and  water  drips  from  it  for  some 
days.  The  proportions  of  the  three  grades  exported  from  Brazil 
are  approximately  :  fine,  62  per  cent.  ;  entrefine,  10  per  cent.  ; 
and  sernamby,  28  per  cent. 

Considerations  Affecting  Amazonian  Yields. 

To  the  planter  in  the  Middle-East,  'the  amount  of  rubber 
got  from  Hevea  brasiliensis  in  its  native  country  is  a  matter 
of  interest,  but  it  is  impossible  to  make  other  than  an  approxi- 
mate estimate.  The  numerous  statements  of  yield  that  are 
available  differ  very  decidedly.  They  may  concern  concessions 
newly  opened  or  others  that  have  been  worked  to  the  full  for 
many  years.  Differences  in  yield  may  be  expected  according  to 
soil  and  other  natural  conditions.  The  collectors  vary  in  dili- 
gence,  and  individually  and  racially  in  skill,   while  dishonesty 


268  PARA     RUBBER 

leads  to  adulteration  and  to  sales  of  the  rubber  to  pirates,  the 
latter  factor  rendering  estimates  made  from  the  books  of  estates 
unrehable.  Trees  may  be  tapped  daily,  on  alternate  days,  some- 
times only  every  three  days  ;  the  tapping  season  varies  in  length  ; 
and  otherwise  there  are  differences  in  the  strain  that  is  imposed 
upon  the  trees.  The  crop  reported  is  perhaps  of  wet,  newly- 
coagulated,  rubber,  which  may  lose  even  30  per  cent,  of  its  weight 
by  the  time  it  reaches  Para  or  Manaos  ;  or  it  is  of  rubber  already 
received  there.  To  take  into  account  only  those  very  few  estimates 
carefully  made  on  certain  estates  would  be  wrong,  for  they  appear 
mostly  to  have  been  made  in  the  more  accessible  regions,  where 
the  trees  must  have  been  well  worked  in  the  past.  Other 
estimates,  where  they  have  not  been  made  from  estate  books, 
are  often  slipshod  and  casual. 

Upon  first  consideration,  it  would  appear  the  better  method, 
when  repeating  the  statements  of  the  different  observers  and 
others  who  have  dealt  with  the  yields  from  Hevea  in  the  wild 
state,  to  include  with  them  such  details  as  are  given  regarding  the 
number  of  cuts  per  tapping  day,  the  tapping  frequency,  and  the 
number  of  tapping  days  ;  but  such  details  are  seldom  complete, 
and  it  is  therefore  an  advantage  to  have  the  statistics  of  yield 
compacted  together,  and  as  far  as  possible  free  from  these  details. 

The  estimates  of  some  thirty-five  authorities  have  been 
examined,  but  they  are  not  all  included  here.  Where  it  is  not 
otherwise  stated,  the  weight  at  Para  or  Manaos  is  understood. 
It  will  be  observed  that  in  addition  to  the  yields  per  tree,  the 
yields  per  estrada  and  per  seringuero  are  frequently  given. 

Yields   in   Brazil. 

The  first  estimate  to  be  presented  is  one  that  has  been 
criticised  on  the  score  of  its  conservatism.  Vice-Consul  Temple, 
of  Para,  who  was  given  access  to  the  books  of  concession-owners 
in  Para  State,  and  to  other  information,  computed  the  average 
yield  per  tree  per  season  at  between  i  and  ij  kilo  (2-2  to  ^-^  lb.), 
and  he  was  of  the  opinion  that  very  many  trees  were  being  worked 
that  gave  no  larger  average  yield  than  0-5  kilo  (i-i  lb.).  .-Vll 
these  trees  were  in  well-worked  regions.  JIany  authorities 
doubt  whether  an  estate  could  be  profitably  worked  with  such 
small  average  yields.  Temple  also  remarks  that  chance  details 
coming  to  hand  from  time  to  time  point  to  the  probabilitv  of  some 
trees  yielding  from  4  to,  10  lb.  each. 

Though  Temple's  estimate  of  the  average  annual  yield  per 
tree  has  been  challenged,  it  does  not  differ  essentially  from  that 
made  by  Pearson,  who  believed  that  the  amount  did  not  exceed 
2  to  3  lb.,  and  was  even  less  in  districts  that  had  been  constantly 
worked  for  a  number  of  years.  Yet  he  elsewhere  acknowledges 
that  there  are  figures  shewing  a  yield  of  11  lb.  per  tree  on  the 
Purus,  15  lb.  on  the  Jurua,  and  of  9  lb.  on  the  Acre.  He  also 
mentions  that  in  the  newly-opened  Acre  territory  collectors  are 
able  to  get  from  13  to  55  lb.  of  rubber  per  day. 


PARA     RUBBER  269 

According  to  Ule,  some  trees  give  an  annual  yield  of  2  kilo. 
(4-4  lb.),  but  very  rich  trees  may  yield  12  kilo.  (26-4  lb.),  the 
average  being  3  kilo.  (6-6  lb).  The  daily  harvest  of  a  collector 
appears  to  be  2  and  3  kilo.  (44  and  6-6  lb.)  ;  the  yearly  average  is 
about  300  kilo.  (660  lb.).  He  records  a  case  where  two  seringueros, 
.working  four  estradas  on  the  Upper  Jurua  on  alternate  days  got 
1,000  kilo.  (2,200  lb.)  in   a  year. 

Sandmann  found  that  the  day's  yield  of  latex  upon  an  estrada 
was  from  2  to  7I  litres  (0-44  to  1-65  gallons),  the  average  being 
5  litres  (i-i  gallons').  In  140  tapping  days  over  two  estradas,  this 
equalled  700  litres  (154  gallons),  from  which  was  obtained  400 
kilo.  (880  lb.)  of  dry  rubber.  The  average  number  of  trees  in  an 
estrada  being  120 — average  girth  43  inches — the  yield  per  tree 
works  out  at  i-66  kilo.  (3"75  lb.).  Upon  the  Lower  Amazon, 
especially  the  islands,  the  crops  are  smaller. 

Though  Bonnechaux  records  estradas  yielding  16  to  20  litres 
daily,  the  average  yield  is  only  about  8  litres  (1-76  gallons) ;  from 
this  average  quantity  7-150  to  7-500  kilo,  of  wet  rubber  can  be 
obtained  which  on  partial  drying  will  be  further  reduced  in 
weight  to  4  kilo.  (8-8  lb.).  An  estrada  in  a  season  gives  400  to 
500  kilo.  (880  to  iioo  lb.).  Assuming,  that  there  are  150  trees,  this 
equals  for  each  tree  from  26  to  33  grammes  (0-922  to  i-i6  oz.)  per 
day,  or  from  2-6  to  3-3  kilo.  (5-72  to  7-26  lb.)  per  year. 

Witt  asserts  that  about  100  trees  are  tapped,  and  that  an 
estrada  generally  gives  from  2  to  3  kilo.  (4-4  to  6-6  lb.)  per  day. 
An  experienced  collector  has  been  known  to  obtain  44  lb.  per  day 
from  70  trees  with  alternate  day  tapping.  By  examining  the  cut 
surfaces  of  the  balls  from  different  regions,  for  they  show  stratifica- 
tion partly  due  to  each  day's  contribution  being  distinctly  shown, 
he  estimated  that  on  the  Acre  an  estrada  gave  12  lb.,  on  the 
Maderia  7  lb.,  on  the  Lower  Purus  5^  lb.,  and  on  the  Javary  4  lb. 
per  day. 

Vasconcellos  puts  the  average  yield  at  2^  kilo.  (5-5  lb.)  and  in 
the  Acre  territory  4  kilo.  (8-8  lb.)  of  dry  rubber. 

Upon  his  famous  journey  to  Brazil,  Wickham  personally 
tapped  70  to  80  trees  and  got  10  lb.  per  day  ;  he  also  stated 
that  an  experienced  Indian  collector  could  get  more. 

On  the  Lower  Amazon,  according  to  Ackermann,  a  collector 
can  get  3  kilo.  (6-6  lb.)  in  a  day  from  an  estrada,  and  easily  three 
times  that  on  the  Upper  Amazon.  In  a  period  of  7  months,  from 
100  trees,  a  man  is  able  to  get  from  400  to  800  kilo.  (880  to  1760  lb.). 

From  these  records  of  Brazilian  yields  we  may  turn  to  those 
from  Peru  and  Bolivia. 

Yields    in    Peru. 

From  Plane's  work  upon  the  Amazon  we  learn  that  on  the 
Madre  de  Dios,  in  Peru,  the  daily  yield  of  a  tree  30  cm.  diameter 
(38  inches  girth)  is  22-5  cm.  (0-78  fluid  oz.)  of  latex,  giving  15 
grammes  of  humid  rubber  and  10  grammes  (0-35  oz.)  of  dry. 
Estradas   at   Vista-Alegre,   Madeira,  worked  for  40  years,  gave  in 


270  PARA     RUBBER 

a  year  not  more  than  225  kilo.  (495  lb.)  per  estrada  and  per  worker 
from  100  trees.  On  the  Upper  Aripuana,  a  collector  got  450  kilo. 
(990  lb.)  in  a  season. 

A  Peruvian  estrada  of  150  trees,  so  Eberhardt  found,  yielded  in 
a  day  about  2  gallons  of  latex,  giving  4^  lb.  of  fine  hard. 

According  to  Castre,  the  average  production  of  each  tree,  in 
the  season  of  8  or  9  months,  tapped  alternate  days,  is  2  kilo. 
(4  lb.  7  oz.)  of  dry  rubber. 

Yields    in    Bolivia. 

Cibot  spent  six  years  upon  the  Rio  Beni,  in  Bolivia,  and  has 
published  some  instructive  details.  Dealing  first  with  the  par- 
ticulars of  an  estrada  of  120  trees,  he  noted  that  the  collector,  in  23 
tapping  days  extending  from  19th  July  to  25th  August,  tapping 
daily  except  for  an  interval  of  14  days,  got  108-24  kilo,  of  latex,  an 
average  of  4705  kilo.  (10-35  lb-)  per  day.  This  latex  was  all 
coagulated  in  one  ball,  which  on  the  25th  August  weighed  73  kilo> 
(160-6  lb.).  By  drying  the  weight  was  reduced  by  2nd  September 
to  66  kilo.  (145-2  lb.)  He  asserts  that,  when  marketed  in  Europe 
the  rubber  is  never,  in  weight,  more  than  half  that  of  the  latex 
whence  it  is  derived.  The  average  yield  per  tree  per  day  was  39 
grammes  (1-37  oz.)  of  latex  and  19-5  grammes  (0-69  oz.)  of  rubber 
marketed  in  Europe.  He  proceeded  to  repeat  the  particulars  of 
the  harvests  of  45  collectors  working  under  him,  each  upon  one 
estrada.  The  average  daily  harvest  over  a  period  of  14  weeks, 
which  formed  one  of  the  two  tapping  seasons  in  the  year,  was 
3-08  kilo.  (6-8  lb.),  weighed  one  month  after  coagulation  ;  deduct- 
ing 20  per  cent,  for  further  drying,  this  was  equal  to  2-464  kilo. 
(5-4  lb.)  in  Europe.  The  best  of  the  workers  got  5-36  kilo.  (11-8  lb.) 
weighed  after  one  month  ;  the  twelve  worst  only  an  average  of  2 
kilo.  (44-4  lb.)  There  being  an  average  of  130  exploitable  trees, 
the  average  yield  per  tree  works  out  at  4-261  kilo.  (9-4  lb.)  for  the 
season. 

In  his  work  upon  the  Bolivian  Andes,  Sir  Martin  Conway 
reported  that  nobody  counted  on  less  than  3  lb.  per  tree  per  year, 
and  no  estimates  were  higher  than  7  lb. 

On  the  estate  of  the  Boston  and  Bolivia  Rubber  Company, 
Dunleavy  went  the  rounds  with  a  collector.  From  345  trees 
ig  lb.  of  rubber  were  obtained.  Sixteen  hours  after  smoking 
the  weight  was  5  J  lb.  less,  and  twenty  days  later  it  had  decreased  by 
a  further  3^  lb.  The  amount  of  the  20-day-old  rubber  per  tree  per 
tapping  works  out  at  0-46  oz. 

The  Average  Yield  on  the  Amazon, 

The  average  amount  of  wet,  newly-coagulated  rubber  obtained 
per  tree  per  season  in  Brazil  seems  to  be  between  six  and  seven 
pounds.  Taking  into  account  the  contained  moisture,  this  is  the 
equivalent  of  not  more  than  3f  to  4I  lb.  of  plantation  rubber. 
Such  a  yield  is  possible  only  because  many  previously  untapped 
trees  are  each  year  brought  into  bearing. 


PARA     RUBBER  271 

The  average  yield  of  from  3f  lb.  to  4I  lb.  of  dry  rubber  from 
old  trees  does  not  seem  at  all  excessive,  and,  if  correct,  can  only 
be  explained  by  assuming  that  the  trees  are  never  taxed  to  the  same 
extent  as  they  are  on  Eastern  plantations  or  that  they  are  badly 
tapped.  In  the  best  areas  in  the  Middle-East  a  yield  of  one  ton 
per  five  acres  (equal  to  4  to  5  lb.  per  tree)  is  by  no  means  uncommon, 
and  yet  the  trees  in  the  East  are  far  younger  than  most  of  those 
tapped  along  the  Amazon.  On  the  other  hand,  one  must  bear  in 
mind  the  fact  that  trees  in  the  East  have  only  been  tapped  during 
the  last  few  years,  while  tapping  in  Brazil  carries  us  back  over 
eighty  years. 

Systematic  tapping  on  anything  approximating  scientific 
principles  is  rarely,  if  ever,  adopted  on  the  Amazon,  and  it  appears 
quite  possible  that  if  proper  supervision  could  be  given,  a  much 
larger  outturn  might  be  obtained  from  wild  trees  in  the  areas 
herein  mentioned. 


CHAPTER   XVI. 

YIELDS    IN    MALAYA. 

Hitherto  it  has  been  impossible  to  give  anything  like  an 
adequate  survey  of  the  yields  likely  to  be  obtained  from  Hevea 
trees  under  cultivation  in  the  Middle-East.  Now,  however,  we 
have  detailed  information  regarding  results  obtained  during  the 
last  six  years  from  Hevea  trees  ranging  from  2f  to  25  years  of  age, 
growing  under  very  dissimilar  conditions  and  tapped  on  systems 
remarkable  for  their  variability  in  principles.  We  possess  records 
of  yields  from  exceptionally  young  and  old  trees,  from  trees 
with  a  difference  of  twenty  years  in  age,  from  individual  estates, 
and  lastly  from  the  whole  of  the  tapped  trees  in  the  Malay  Penin- 
sula during  specified  years. 

The  yields  obtained  during  the  last  five  years  in  Malaya 
have  been  largely  responsible  for  stimulating  interest,  agri- 
culturally and  financially,  in  the  rubber-planting  industry.  There 
are  now  about  a  hundred  London  companies  producing  rubber  in 
Malaya  alone,  and  the  yields  obtained  over  large  acreages  as 
well  as  from  notable  trees  have  so  far  given  every  satisfaction. 

Early  Yields  from  Trees  of  Know.n-  Age. 

The  following  results  (Rep.  by  Stanley  Arden),  are  of  consider- 
able interest,  as  they  show-  the  yield  obtained,  many  years  ago, 
by  tapping  trees  of  different  ages  on  12  alternate  days  by  the 
herring-bone  system  ; — 

Age.  Yield. 

Years.  Ounces. 

3i  ■■■  1-54 

4  i»  2'26 

7  -..  14-27 

8  to  9  ..  16-76 

ID  to  12  ..  2825 

From  these  and  other  results  Arden  concluded  that  trees  under 
four  years  were  too  young  to  be  tapped,  and  that  an  average 
annual  yield  of  12  ounces  per  tree  should  be  obtained  from  trees 
6  years  old.  Of  late  years,  however,  these  results  have  been 
largely  exceeded. 

Further  results  obtained  by  Ridley  and  others  have  been 
published  from  time  to  time,  and  from  them  the  following  synopsis 
is  made.  The  range  in  yield  varies  from  10  ounces  per  tree  for 
6-year-old  trees  to  9  lb.  per  tree  for  older  specimens  ;  in  one 
case  as  much  as  3  lb.  of  rubber  has  been  reported  from  a  well- 
grown  three-year-old  tree.  Some  trees,  having  a  circumference  of 
36  inches,  have  given  3  lb.  of  dry  rubber  per  tree  ;    other  trees, 


•fo. 

Circumference  3  ft 

I 

2 

3 
4 

from  ground. 
17J  in. 
26J  „ 
26J  „ 
39i  „ 

5 

— 

PARA     RUBBER  273 

24  inches  or  more  in  circumference,  have  been  known  to  give  only 
2^  oz.  of  dry  rubber  each,  probably  on  account  of  their  being  too 
young. 

Yields  from  Young  Trees  in  Malaya. 

The  yield  from  very  young  trees  is  by  no  means  insig- 
nificant. An  experiment  was  made  in  Selangor  during  1909  with 
2,845  trees  which  were  only  2f  years  old.  These  were  tapped 
for  two  months  and  gave  an  average  yield  of  0^297  lb.  per  tree. 
Tapping  for  only  eight  months  2,843  trees,  3-|-  years  old,  gave 
I "24  lb.  per  tree,  and  in  nine  months  6,426  trees,  3|  years  old, 
gave  i-o6  lb.  per  tree. 

Another  record  shows  that  6,444  trees,  4f  years  old,  gave 
in  two  months  0-178  lb.  per  tree,  and  4,420  trees,  5|  years  old, 
for  the  same  period,  yielded  0-248  lb.  each.  In  another  field, 
400  trees,  4I  years  old,  tapped  for  six  months  gave  1-107  1^-  P^r 
tree,  and  4,674  trees,  5|  years  old,  during  the  same  period,  re- 
turned an  average  of  0-961  lb.  per  tree. 

A  large  number  of  trees,  all  5f  years  old,  were  tapped  during 
1909  for  two,  four  and  six  months,  and  yielded  respectively 
0-248,  0-503  and  0-997  lb-  per  tree,  or  an  increase  of  approximately 
50  per  cent,  for  each  two  months'  tapping. 

Some  trees  3  J  to  4^  years  old  in  the  Straits  Settlements 
and  in  Klang  have  given  at  the  rate  of  nearly  one  lb.  of  rubber  per 
annum,  per  tree.  The  bark  of  these  trees  is  relatively  soft  and 
does  not  compare  favourably  with  the  harder  texture  of  that  on 
trees  which  have  taken  a  longer  time  to  attain  the  tappable  size. 

Excellent  results  have  been  obtained  on  Malay  estates 
by  cutting  a  large  V  or  Y  at  a  foot  to  eighteen  inches  from  the 
base  of  the  tree,  the  V  extending  half  round  the  tree.  When 
the  tree  is  large  enough,  a  second  V  is  cut  on  the  reverse  side. 
By  such  a  method  the  young  trees  can  be  tapped  regularly — 
almost  every  alternate  day — the  rubber  is  extracted  only  from 
the  thick  part  of  the  bark,  and  a  high  yield  is  obtained  from  the 
basal  regions. 

Yields  from  Old  Trees  in  Malaya. 

In  rnarked  contrast  with  the  above  are  the  unexpectedly 
high  yields  obtained,  in  twelve  months,  from  individual  trees 
on  various  properties.  On  Jugra  estate  seven  to  nine-year-old 
trees  gave  7  lb.  per  tree,  and  on  Cicely  eight-year-old  trees  gave 
8  lb.  The  Federated  Malay  States  Company  possess  over  2,900 
9j-year-old  trees  which  gave  24,000  lb.  of  rubber  in  one  year,  or 
an  average  per  tree  of  8-2  lb.  Twelve-year-old  trees  on  Linggi 
yielded  10-7  lb.  in  twelve  months,  Batu  Unjor  is  reported  to 
have  secured  10-73  lb.  per  tree  from  6,800  trees  at  the  age  of  from 
II  to  12  years.  A  yield  of  28|  lb.  is  also  recorded  from  the  17- 
year-old  trees  growing  near  the  churchyard  at  Parit  Buntar. 
Similarly  high  yields,  equal  to  one  pound  of  rubber  for  each  year's 
growth,  have  been  published  from  time  to  time,  but  it  is  extremely 


274  PARA     RUBBER 

doubtful  whether  such  yields  can  be  relied  upon  annually  In 
several  instances  the  trees  have  been  growing  under  exceptionally 
favourable  conditions,  and  many  do  not  appear  to  have  been 
tapped  until  they  attained  quite  a  good  age. 

Yields   from   Old  Trees   of    Doubtful   Age. 

The  old  tree  in  the  Penang  Botanic  Gardens  was  tapped  during 
1908,  and  yielded  3  lb.  8  oz.  of  dry  rubber,  making  the  total  yield 
since  the  first  tapping  over  40  lb. 

An  old  Hevea  tree  at  the  Singapore  Botanic  Gardens  was 
tapped  in  November  and  December,  1906,  and  4  lb.  4J  oz.  of  dry 
rubber  obtained  ;  that  made  a  total  of  35  lb.  13^  oz.  from  the  tree 
since  it  was  first  tapped.  The  tree,  which  was  about  twelve 
years  old,  reached  a  greater  production  in  1905,  when  4  lb.  12J  oz. 
of  rubber  was  obtained. 

The  report  of  Mr.  W.  Peel,  the  Agricultural  Superintendent  of 
the  Gardens,  on  the  tapping  operations  during  1906,  showed  that 
though  the  old  tree  in  the  Botanic  Gardens  which  was  tapped  14 
times  between  November  19th  and  December  15th,  gave  4  lb. 
4J  oz.  of  dry  rubber,  the  same  number  of  operations  on  trees  on 
Penang  Hill,  carried  out  between  July  nth  and  August  6th, 
yielded  only  from  11^  oz.  to  2  lb.  14  oz. 

Two  very  old  trees  at  Perak,  having  a  circumference  of  56  to  89 
inches  respectively,  and  reported  to  be  25  years  old,  have  given  in 
two  months'  tapping  no  less  than  12  and  18  lb.  of  dry  rubber, 
including  scrap. 

Yield  from  Trees  3  to  25  Years  Old. 

It  is  eminently  desirable  that  some  attempt  should  be  made 
to  determine  the  average  yield,  per  tree  and  per  acre,  from  trees  of 
known  age.  As  in  other  statistics  of  this  character  compiled  by 
managers  of  estates  who  may  not  have  planted  the  trees  they  have 
tapped,  there  is  a  hability  to  error  which  cannot  be  ehminated. 
The  figures  in  the  column  headed  ' '  age ' '  refer,  when  no  range  of 
age  is  given,  generally  to  the  age  of  the  trees  when  tapping  was 
first  commenced.  Where  a  range  in  age  is  indicated,  this  usually 
covers  the  period  of  tapping  for  which  particulars  are  given.  The 
total  number  of  tapped  trees  shown  does  not  necessarily  indicate 
the  number  tapped  during  the  whole  of  the  year,  many  trees  being 
added  to  the  tapping  round  month  by  month.  It  is,  therefore, 
fair  to  assume  that  the  average  yields  given  err  on  the  low  side. 

Unfortunately,  though  details  of  times  of  planting  are  available 
in  the  prospectuses  of  many  companies,  the  yield  from  trees  planted 
in  successive  years  are  not  always  given  in  the  annual  reports. 
In  such  cases  the  age  of  the  tapped  trees  is  a  matter  of  conjecture 
and  the  available  details  have  therefore  been  rejected. 

The  information  has  been  arranged  to  show  the  yield  from 
numerous  estates  from  trees  of  approximately  the  same  age. 
It  should  be  borne  in  mind,  when  dealing  with  the  yields  in  later 
years,  that  these,  in  most  cases,  have  been  obtained  from  the  same 
trees. 


PARA     RUBBER  275 

Trees  Three  to  Five  Years  Old. 

Trees  in  Malaya,  3  to  4  years  old,  have  yielded,  within  twelve 
months,  from  0-53  to  1-24  lb.  per  tree,  and  at  the  rate  of  from 
104!  to  148^  lb.  per  acre,  even  though  every  tree  has  not  been 
tapped  regularly  throughout  the  year. 

Hevea  trees.  Yield  in  lb. 

Name.                  Age.  Number.  Acres.  Total.  Per  tree.  Per  acre. 

F.M.S 3i           2,483  —  3,084  1-24  — 

3}           6,426  46  6,871  i'o6  148 

3}           7.859  60  6,163  °'7^  i°2 

4             4.536  33  4,317  095  129 

Straits  Bertam    ..        3-5  23,000  211  12,296  O'sg  58 

Bagan  Serai         ..       3-4           8,536  51  5,669  066  iii 

Straits  Rubber    .  .        3-5  15,509  89  12,929  0-83  145 

Batak  Rabit                   4  23.400  119  12.457  °'53  '°5 

Sungei  Krian       .  .        3-5           7.170  —  8,680  i'2i  — 

Batu  Caves                 3J-5  56,258  —  95,894  170  — 

The  trees  on  Batak  Rabit  were  tapped  six  months  only  ; 
on  Bagan  Serai,  7  months  ;  on  Straits  Rubber  Estate,  8  months  ; 
on  the  F.M.S.  estates,  8  or  9  months  ;  on  Batu  Caves,  from 
8  to  12  months;    and  on  Sungei  Krian,  11  months. 

Several  trees,  3  to  7  years  old,  on  Carey  estate,  yielded  at  the 
rate  of  1-84  lb.  each.  Others,  3-11  years,  on  Lanadron,  gave  4-13 
per  tree,  or  at  the  rate  of  448  lb.  per  acre  per  annum.  Over  15,000 
closely-planted  trees,  3  to  12  years  old,  on  Pandan  (Johore),  gave 
an  average  of  309  lb.  per  acre.  On  Linggi,  151,796  trees,  3-J  to 
12  years  old,  yielded  3-59  lb.  each,  and  a  further  285,000,  3  to  13 
years  old,  gave  3-08  lb.  per  tree. 

Further  details  of  the  Carey  estate  show  that  trees  3  to  7 
years  old  each  gave  I'Si  lb.,  and  in  another  year  those  3  to  8, 
years  gave  1-65  lb.  each. 

Trees  Four  to  five  Years. 

In  this  group  tapping  does  not  appear  to  have  been  carried 
out  every  month  of  the  year.  Nevertheless,  yields  of  fi'om  0-46 
to  1-68  lb.  per  tree,  and  of  42  to  292  lb.  per  acre,  have  been 
chronicled. 


Hevea  Trees 

Yield  in  lb. 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree. 

Per  acre 

Castlefield 

4-5 

34.376 

270 

18,820 

055 

70 

F.M.S 

4-5 

8,489 

— 

— 

124 

Banteng  (Selaugor) 

5 

5.463 

50 

6,600 

1'2I 

132 

Selangor  . . 

4 

— 

— 

— 

— 

60 

.. 

5 

— 

— 

— 

1-70 

90 

Klanang  .  . 

4-5 

12,500 

140 

5.904 

046 

42 

„ 

4-5 

22,500 

380 

23.446 

l'04 

62 

Bakap 

4-5 

13,128 

— 

22,161 

1-68 



Glenshiel 

5 

3.953 

21 

6,290 

159 

293 

Seafield    . . 

4 

7,240 

120 

5.215 

0-72 

43 

4-5 

70,790 

538 

94.519 

l'33 

175 

Jeram 

4-5 

15.973 

254 

14.152 

0-88 

55 

Changkat  Salak  . . 

4 

99 

14,600 

— 

147 

Batu  Tiga 

4 

19,000 

— 

12,000 

063 

Gula  Kalumpong 

4-5 

73,000 

— 

— 

0-75 

— 

276  PARA     RUBBER 


Hevea  Trees. 

Yield  in  11 

>, 

Name, 

Age. 

Number 

Acres. 

Total. 

Per  tree. 

Per  acre 

Batu  Unjor 

4-5 

22,472 

262 

35.638 

1-5 

136 

Sendayan 

4-s 

19,380 

174 

17.537 

0-90 

100 

Batak  Rabit 

4-5 

23,000 

27,009 

I  17 

— 

Lumut 

4-5 

37.595 

— 

33.702 

0-90 

— 

Taiping 

■        4-4i 

50,000 

— 

52,?oo 

1-05 

— 

The  Castlefield  and  F.M.S.  trees  were  tapped  for  nine  months, 
the  Banteng  for  eight,  the  first  group  of  the  Klanang  (12,500 
trees)  for  five,  and  the  first  group  of  the  Seafield  (7,240  trees), 
for  four  months  only. 

Trees  Four  to  Nine  Years. 
It  would  not  be  wise  to  take  an  average  age  for  trees  ranging 
from  four  to  nine  years  old,  and  separate  figures  are  therefore 
given  showing  the  yields  obtained  according  to  range  in  age. 
On  Tremelbye  nearly  half  the  trees  were  tapped  for  a  few  months 
only  ;  on  Banteng  and  the  Straits  Rubber  the  tapping  was  mainly 
basal,  whereas  on  Vallambrosa  the  5delds  were  from  high 
tapping. 

Hevea  trees.  Yield  in  lb. 

Name.  Number.     Acres.        Total.    Per  tree.    Per  acre. 

Four  to  six  years. 

Banteng  . . 

Straits  Rubber  .  . 

Jementah 

Sungei  Krian 
Four  to  seven  years. 

Shelford  . . 

Chersonese 

Kapar  Para 

Seremban 

Vallambrosa 

Tremelbye 

Sengat 
Four  to  eight  years, 

Glenshiel 
Four  to  nine  years. 

Glenshiel 

Kinta  Kellas 

Bukit  Rajah 

There  are  other  yields  from  trees  4  years  old  and  upwards, 
which  are  worth  chronichng.  The  Merton  Rubber  Syndicate 
and  Allagar  obtained  from  trees,  4  to  10  years  old,  160J  and  310^ 
lb.  respectively  per  acre  in  one  year.  Consolidated  Malay  reported 
a  crop  of  3-44  lb.  per  tree  from  99,225  trees,  4  to  12  years  old. 
Inch  Kenneth  obtained  from  621  acres,  4  to  15  years  old,  a  crop 
at  the  rate  of  277  lb.  per  acre. 

Trees  Five  to  Six  Years   Old. 

Including  the  experimental  work  on  Jugra,  Sempah,  and 
oji  Highlands  and  Lowlands,  the  yield  from  trees  belonging  to 
this  class  ranges  from  o-88  to  2-38  lb.  per  tree,  or  95J  to  296  lb. 
per  acre. 


16,300 

200 

32,000 

1-96 

160 

217,000 

1,824 

209,449 

0-97 

"5 

— 

— 

— 

1-95 

96 

4,700 

— 

8,680 

1-85 



20,000 

184 

U.548 

057 

63 

24,000 

— 

27.659 

115 

— 

— 

800 

169,610 

— 

212 

36.750 

— 

68.957 

1-88 

— 

955 

371.316 

— 

388 

108.761 

1,076 

101,601 

094 

95 

40,811 

— 

116,763 

286 

13,000 

91 

5,679 

0-44 

61 

64,000 

428 

48,000 

075 

112 

30,000 

— 

30.085 

i-oo 

— 

88,341 

720 

118,982 

135 

165 

PARA     RUBBER 


277 


Hevea  trees. 

Yield  in  lb. 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree. 

Per  acre 

Jugra 

•        54 

6,820 

26 

— 

0-39 

103 

Batu  Unjor 

■       5-6 

39,874 

— 

38.952 

0-97 

Seremban 

•       5-6 

83 

20,086 

242 

Cons.  Malay 

.  Over    5 

853.390 

683 

202,440 

2-33 

296 

F.M.S.      . . 

•      5i 

7,020 

— 

16,739 

238 

— 

Seafield    .. 

■       5-6 

21,600 

238 

38,572 

1-79 

161 

Klanang 

.       5-5i 

9,564 

105 

14,072 

1-49 

134 

Kurau 

•       5-6 

24,000 

220 

21,036 

0-88 

95 

Sempah    .  . 

■       5-6 

6.367 

— 

4,071 

0-64 

Eow  Seng  .  . 

■       5-6 

7,800 

— 

9,411 

I-2I 

— 

H.  &  L.    . . 

■       5-6 

37.269 

406 

28,087 

o'75 

69 

Castlefield  (Klang 

)       5-6 

67.558 

541 

72,401 

i-o6 

134 

Rubana    . . 

•       5-6 

69,000 

607 

81,921 

I-I9 

114 

On  Jugra  estate  the  trees  were  only  tapped  39  times,  and  on 
Batu  Unjor  only  light  tapping  was  indulged  in.  On  Seafield  the 
trees  were  tapped  for  eleven  months,  and  on  Highlands  and 
Lowlands  about  half  of  the  trees  were  brought  into  the  tapping 
round  in  the  last  six  months. 


Trees  Five  to  Seven  Years  Old. 

A  yield  of  from  i-^fi  to  3-93  lb.  per  tree  and  up  to  405  lb. 
per  acre,  per  annum,  shows  a  decided  advance  above  the  yields 
previously  recorded. 


Hevea  trees. 

Yield  in  lb 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree. 

Per  acre. 

Pataling  .  . 

■       5-7 

— 

— 

— 

— 

236 

F.M.S. 

•     5i-6J 

6,467 

80 

18,877 

292 

236 

,, 

■      5i-6i 

3,880 

lOI 

9,607 

2' 47 

94 

Balgownie 

•     5i-6i 

7,800 

— 

10,642 

1-36 

— 

Rubana    .. 

5-7 

107,204 

977 

245.384 

229 

251 

Batu  Caves 

•       5-7 

15.462 

60,754 

393 

— 

Batu  Unjor 

5-7 

5.356 

46 

18,630 

3-48 

405 

Selangor  . . 

5-7 

— 

440 

29,750 

— 

67 

On  Jugra  Island  a  yield  of  400  lb.  per  acre  was  reported  by 
Carey  from  trees  planted  10  by  10  feet,  though  they  were 
only  from  5^  to  6 J  years  old. 

Trees  Five  to  Eight  Years  Old. 

The  statistics  relating  to  this  group  are  not  very  numerous  ; 
the  maximum  yield  per  tree  appears  to  have  been  less  than  4  lb. 


Hevea    trees. 

Yield  in  lb 

Name. 

Age.       Number. 

Acres. 

Total. 

Per  tree. 

Per  acre 

Rembia    . . 

■     5i-7J          3.750 

— 

11,000 

2-93 

^25 

F.M.S.      .  . 

■     5i-7i          3.287 

— 

11.654 

3'55 

— 

,, 

•   5i-7i        4.653 

— 

17.427 

3'74 

— 

Rembia    .  . 

5-8            7.500 

40 

8,361 

I'll 

206 

Shelford  .. 

.      5-8          24,250 

184 

23.828J 

— 

129 

Selangor  . . 

.       5-8              — 

553 

70,577 

— 

127 

Cons.  Malay 

5-8           11,348 

— 

32,693 

2-88 

Bukit  Rajah 

•       5-8           34.457 

— 

33,203 

0-97 

— 

Vallambrosa 

.      5-8              — 

930 

156,922 

— 

169 

The  crops  from  the  F.M.S.  properties  were  obtained  in  eleven 
months  of  tapping.  On  Selangor  36I  acres  were  tapped  for  the 
first  time  late  in  the  year. 


278 


PARA     RUBBER 


Trees  Five  to  Twelve  Years  Old. 
In  this  division  there  is  naturally  a  great  variation  in  5deld. 
A  maximum  crop  of  443  lb.  per  acre  is  recorded,  and  one  of  3-96  lb. 
per  tree,  from  Lanadron. 

Name. 
Five  to  nine  years. 

Golconda . . 

Shelford   . . 

Bukit  Rajah 

Cons.  Malay 
Five  to  ten  years. 

R.E.  of  Krian 

Bukit  Rajah 

Labu 

Lanadron 

Shelford   . . 

Cons.  Malay 
Five  to  eleven  years 

Selangor  . . 

Bukit  Rajah 

I^bu 

Cons.  Malay 

North  Hummock 
Five  to  twelve  years. 

Bukit  Rajah 

Labu 

H.  and  L. 

Vallambrosa 
Five  to  thirteen  years 

Bukit  Rajah 

Of  the  329  acres  on  Golconda,  five  to  nine  years  old,  106  were 
five  years  old,  and  this  accounts  for  the  relatively  low  yield.  On 
Labu  the  trees,  five  to  ten  years  old,  were  mixed  with  other 
products  ;  and  those  of  a  similar  age  on  Shelford  included  a 
large  number  of  young  trees.  The  yield  from  five  to  twelve-year- 
old  trees  on  Highlands  and  Lowlands  was  partly  obtained  from 
high  tapping.  That  given  for  Vallambrosa  was  partly  from  217 
acres  tapped  for  the  first  time. 


Hevea 

trees. 

Yield  in  lb 

Number. 

Acres. 

Total.  Per  tree. 

Per  acre. 

— 

329 

35.103 

— 

107 

— 

395 

33.o97i 

— 

83 

88,341 

720 

118,982 

i'34 

165 

17.549 

200 

63.615 

362 

318 

14,000 

— 

41,200 

29 

435 

89.295 

800 

163,521 

1-83 

204 

23,000 

140 

28,775 

125 

205 

— 

565 

249,247 

396 

443 

65.333 

— 

103,104 

1-58 

— 

34,000 

— 

111.585 

3-28 

— 

138,600 

924 

326,654 

23 

353 

94,600 

950 

210,081 

2'22 

221 

27,670 

205 

86,763 

313 

423 

57.145 

— 

215.893 

3-77 

— 

28,476 

— 

86,561 

304 

— 

125,000 

1.250 

314.778 

251 

251 

64,000 

520 

203,696 

3-i8 

391 

53.352 

720 

166,135 

311 

230 

— 

1,172 

411,476 

— 

351 

128,000       1,470         437.997        342 


298 


Trees  Six  to  Seven  Years  Old. 

Including  the  first  three  records,  the  yield  per  tree  varies  from 
I  to  5-72  lb.,  or  from  128  to  318  lb.  per  acre.  It  is  probable  that 
the  yield  per  acre  is  considerably  higher  than  this  on  many  estates, 
but  particulars  are  not  available  for  pubhcation. 


Hevea  trees. 

Yield  in 

lb. 

Name. 

Age.         Number. 

Acres. 

Total. 

Per  tree 

.  Per  acre 

Jugra 

6i                5,500 

38 

4,041 

073 

106 

Malacca    .  . 

.    6J  to  7          30,000 

— 

13,000 

— 

Selangor  .  . 

6                    — 

— 

— 

— 

140 

Klanang  .  . 

6                 16,000 

54 

13,218 

083 

244 

Harpenden 

6                    — 

22 

3.713 

— 

168 

Shelford  .. 

6                  9,636 

76 

6,808 

0-77 

128 

Seafield    .  . 

6-7            36,053 

238 

106,886 

2-97 

224 

Klanang  .  . 

6                18,900 

94 

30,028 

i-6o 

318 

Vallambrosa 

6-7              6,225 

40 

6,225 

I'OO 

155 

Straits  Bertam    . 

.6  and  over     16,782 

19,781 

117 

PARA     RUBBER 


279 


Hevea  trees. 

Yield  in  lb 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree.  Per  acre 

F.M.S.      . . 

•      6i 

3.820 

45 

10,114 

264 

221 

•        6i 

6,065 

59 

15.037 

2-47 

254 

•        H 

4.915 

— 

11,969 

2-43 

— 

■        6i 

5.225 

61 

15.710 

300 

257 

•        6i 

3.486 

— 

8,411 

2-41 

•        6i 

4,208 

— 

6,858 

1-63 

— 

Anglo-Malay 

•        6-7 

28,326 

— 

47.788 

1-68 

— 

.. 

•        6-7 

5.440 

— 

18,112 

3-32 

— 

The  trees  on  Malacca  were  tapped  fro  .11  April  to  October, 
and  some  of  those  on  Shelford  for  a  few  months  only.  The  trees 
on  Klanang  were  planted  12  ft.  by  12  ft.  apart,  and  were  tapped  on 
the  half-herring-bone  system.  Those  on  Vallambrosa  were 
originally  planted  10  ft.  by  12  ft.  apart.  The  Seafield  trees  were 
tapped  for  eight  months  on  the  full  herring-bone  system. 

Trees  Six  to  Eleven  Years  Old. 

The  range  in  age  is  considerable,  and  it  is  hardly  a  matter 
for  surprise  that  yields  of  over  4  lb.  per  tree  have  been  obtained 
from  large  numbers  of  trees. 

Name. 
Six  to  eight  years. 
Cicely 
Jugra 

F.M.S. 


Hevea  trees. 
Number.     Acres. 

Yield  in  lb 
Total.   Per  tree. 

Per  acre. 

6,919 

4,807 
5.383 
4.493 

72 
159 

54 

163 

9,184 

21,680 
17,426 

14.324 
18,722 

133 

4-51 
3-23 
318 

193 
136 
319 

114 

18,150 
152,195 

182 
930 

34.770 
225,302 

1-91 

1-48 

191 

242 

48,823 

3,812 

22,000 

656 

131.252 
19.756 

2-68 

519 
4'oo 

200 

308       115.895 


376 


Golconda 
Six  to  nine  years. 

Perak 

Vallambrosa 
Six  to  ten  vears. 

H. and  L. 

F.M.S.      . . 

Gula  Kalumpong 
Six  to  eleven  years. 

Perak 

On  Perak  96  acres  were  nine  years  old  and  a  higher  yield 
might  have  been  reasonably  anticipated.  On  Highlands  and 
Lowlands  7,128  trees  were  taken  in  during  the  second  half  of  the 
year. 

Trees  Seven  to  Eight  Years  Old. 

The  yield  from  trees  of  this  age  is  much  more  regular,  as  the 
whole  of  the  trees  on  each  acre  are  usually  in  the  tapping  round. 
The  crop  of  555  lb.  per  acre  from  such  a  large  acreage  on  Sungei 
Kapar  can  be  regarded  as  above  the  average,  though  from  4  to  5 
lb.  per  tree  are  frequently  heard  of  at  the  above-mentioned  ages. 


Hevea  trees. 

Yield  in  lb 

Name. 

Age.         Number. 

Acres. 

Total. 

Per  tree. 

Per  acre. 

Klanang  . . 

7             16,000 

54 

15,244 

095 

282 

Golden  Hope 

. .       7                  880 

— 

2,400 

2-9 

— 

Batu  Unjor 

. .       7-8           36,312 

369 

89,565 

2-46 

242 

Sungei  Kapar 

•■   7to7i       39,276 

207 

114,970 

292 

555 

Lanadron 

..Average    1 

7J        )      - 

567 

181,156 

2-44 

319 

28o 


PARA     RUBBER 


3evea  trees. 

Yield  in  J  b. 

Name. 

Age. 

Number. 

Acres 

Total. 

Per  tree 

Per  acre 

Ledbury  Estate 

.  Average 

}   - 

7 

— 

— 

460 

285 

Sione  Estate 

■      7* 

— 

— 

339 

246 

Jugra 

•      7 

120 

— 

— 

206 

— 

II                  -   - 

■      7i 

7,o68 

34 

— 

115 

240 

Allagar     .. 

.   7to8 

— 

— 

3-00 

— 

Anglo-Malay 

.   7to8 

28,043 

— 

105,655 

376 

— 

Malacca   . . 

.   7ito8 

12,000 

— 

46,890 

3-9 

— 

Selangor  . . 

•       7 

— 

— 

— 

— 

140 

In  connection  with  the  small  jdeld,  per  tree,  on  Klanang,  it 
should  be  mentioned  that  the  field  was  planted  12  ft.  by  12  ft. 
The  yield  of  1-15  lb.  per  tree  on  Jugra  was  obtained  from  trees 
tapped  71  times. 

Trees  Seven  to  Thirteen  Years  Old. 
Carey  has  reported  a  yield  of  7  lb.  per  tree  from  trees  seven 
to  nine  years  old.     This  is  quite  in  excess  of  the  average  so  far 
recorded  over  large  acreages. 


Hevea  trees. 

Yield  in  lb 

Name. 

Number. 

Acres. 

Total. 

Per  tree. 

Per  acre 

Seven  to  nine  years. 

Cicely 

8,020 

— 

19,069 

237 

— 

Seven  to  ten  years. 

Vallambrosa 

— 

930 

272,741 

— 

293 

Labu 

8,000 

60 

18,977 

237 

316 

Ledbury  .  . 

— 

175 

28,741 

308 

163 

Batu  Caves     .... 

3. 131 

16.479 

526 

Seven  to  eleven  years. 

H.  and  L. 

46,167 

656 

132,722 

2-87 

202 

Seven  to  thirteen  years. 

H.  and  L. 

■  ■        58.444 

682 

224,335 

384 

329 

The  trees  on  Labu  were  among  other  products,  and  those  on 
Batu  Caves  were  in  coffee.  Those  on  Highlands  and  Lowlands, 
seven  to  eleven  years  old,  included  5,252  trees  which  were  tapped 
for  six  months  only. 

Trees  Eight  to  Nine  and  More  Years  Old. 
It  will  be  noted  that  again  high  yields  of  5  lb.  per  tree  and 
over  400  lb.  per  acre  are  common.  An  eight-year-old  tree  on 
Cicely  estate  has  been  reputed  to  jdeld  8  lb.  of  rubber  in  100 
tappings  during  a  period  of  two  months  only.  Maude  also  states 
that  1,470  trees,  eight -and  a-half  years  old,  gave  30  lb.  of  rubber 
daily  plus  8  lb.  of  scrap. 


Hevea  trees. 

Yield  in  lb 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree. 

Per  acre 

Castlewood 

.    8t0  9 

1.508 

— 

2.934 

1-95 

Selangor  . . 

.        8 

— 

— 

300 

Golden  Hope 

8 

880 

— 

4.615 

550 

Jugra 

.        8 

150 

— 

356 



Seremban 

8 

348 

109.055 

313 

Vallambrosa 

8 

4,642 

60 

12,765 

— 

212 

Klanang  . . 

8 

16,000 

54 

18,886 

Ii8 

349 

Cicely 

.     8-10 

9,000 

43.696 

485 

Jugra       . . 

.        8J 

6,060 

38 

251 

400 

PARA     RUBBER 


281 


Hevea  trees. 

Yield  in  lb. 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree 

Per  acre 

Selinsing 

. .     8  to  9 

1,400 

— 

4.330 

3"  09 

— 

Jugra 

.  .   SJ  to  9 

270 

— 

5i 

— 

Sione 

. .   8|  to  9 

5.967 

— ■ 

8.385 

I  40 

— 

Lanadron 

1      H     ( 

1  Average  1 

— 

565 

249,247 

396 

443 

Batu  Unjor. 

. .  Up  to  9 

43.130 

425 

180,124 

4'I7 

423 

Batu  Tiga 

.  .     8-12 

— 

364 

84,000 

230 

Pataling  .  . 

..     8-13 

— 

372 

205,169 

— 

548 

The  trees  on  Jugra  which  gave  5  J  lb.  and  3  J  lb.  of  rubber  each 
were  in  avenues  ;  those  which  gave  2-$i  lb.  were  tapped  90  times 

Trees   Nine   to   Ten    Years    Old. 

The  very  large  yield,  per  tree,  from  Highlands  and  Lowlands 
(H.  and  L.)  was  obtained  from  trees  planted  30  by  25  feet  apart,  and 
it  will  be  noted  that  the  yield  per  acre  was  below  that  from  other 
properties  of  the  same  age. 


Hevea  trees 

Yield  in  lb 

Name. 

Age.        Number. 

Acres. 

Total. 

Per  tree. 

Per  acre 

Vallambrosa 

5             36,301 

150 

54.451 

i"5 

363 

H.  and  L. 

9                   807 

16 

5,742 

7-01 

359 

Seremban 

9                  — 

348 

109,055 

313 

Sione 

.gjtoioj       6,296 

— 

15.027 

239 

— 

Jugra 

.gjtoio            270 

— 

— 

800 

— 

Batu  Unjor 

.   9  to  10       28,500 

196 

126,961 

4-45 

647 

F.M.S.      . . 

•       9i             2.953 

— 

24.245 

8-21 

— 

It 

9i             2,395 

— 

9,342 

3"9 

— 

Klanang  Produce 

9               8,400 

54 

34,068 

4'05 

630 

Selangor  . . 

9                   — 

— 

— 

— 

400 

On  Cicely  estate,  9,000  trees,  from  9  to  11  years  old,  gave  a 
yield  of  6  lb.  each.  The  crop  of  363  lb.  per  acre  from  Vallambrosa 
was  obtained  from  areas  which  had  been  thinned  out.  The  same 
remark  apphes  to  the  crop  of  630  lb.  from  Klanang. 


Trees  Ten  to  Eleven  Years  Old. 

Yields  of  5,  8,  and  even  9  lb.  per  tree  and  from  500  to  700  lb. 
per  acre  are  recorded  for  trees  of  this  age. 


Hevea  trees. 

Yield  in 

b. 

Name. 

Age. 

Number, 

Acres. 

Total. 

Per  tree 

Per  acre 

Seremban 

10 

36,120 

348 

134,848 

3'73 

387 

Selangor  . . 

10 

— 

— 

— 

— 

500 

F.M.S.      . . 

10 

2,953 

— 

27,560 

932 

250 

loi 

3,860 

— 

31,780 

8-24 

— 

10 

1,707 

— 

5,212 

305 

396 

Klanang  Produce 

10 

8,400 

54 

40,026 

477 

741 

Batu  Tiga 

10 

3,183 

17 

9,316 

293 

548 

Linggi       .  . 

10 

— 

— 

— 

6-5 

— 

Ledbury 

(Sione 

Estate) 

lO-II 

9,655 

112 

37,477 

5-35 

221 

The  9,000  Cicely  trees,  when  10  to  12  years  old,  gave  about 
8  lb.  each  in  twelve  months.  On  Jebong  a  yield  of  7I  lb.  per  tree 
was  recorded  from  several  trees  10  to  13  years  old. 


282  PARA     RUBBER 

Trees  Eleven  to  Twelve  Years  Old. 
The  same  estates  are  again  credited  with  securing  phenomenaJly 
high  yields  from  their  notable  trees.     Batu  Tiga  heads  the  list  with 
758  lb.  per  acre,  and  the  F.M.S.  and  Batu  Unjor   are   prominent 
with  an  outturn  of  from  9  to  10  lb.  per  tree.  • 


Hevea  trees. 

Yield  in  lb 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree. 

Per  acre. 

Seremban 

II 

36,120 

350 

205,542 

5-69 

506 

12 

36,120 

350 

304,620 

8-43 

870 

Selangor  . . 

— - 

— ■ 

— 

600 

Batu  Tiga 

3,183 

17 

12,887 

4-05 

758 

Singapore  Para   . 

9,000 

65 

25.547 

2-84 

393 

Linggi      . . 

— 

— 

— 

800 

— 

F.M.S.      . . 

3,860 

no 

35,444 

918 

321 

Batu  Unjor 

11-12 

6,800 

162 

72,987 

10-73 

450 

,, 

11-12 

940 

12 

6,357 

676 

528 

The  940  trees  on  Batu  Unjor  were  tapped  for  nine  months  on 
the  half-herring-bone  system. 

Trees  Twelve  Years  Old. 
Twelve-year-old  trees  at  Taiping  yielded  3-9  lb.  of  rubber  each 
in  one  series  of  tappings  ;  the  length  of  the  tapping  period  is  not 
given.     Other  trees  of  the  same  age  on  Linggi  estate  have  given 
10-7  lb.  each  in  one  year. 

Trees  Fourteen  Years  Old. 

Other  trees  at  Perak,  14  years  old,  have  given  an  average  yield 
of  over  4  lb.  each,  and  others  of  the  same  age  quoted  by  Johnson 
show  a  yield  of  3  lb.  i  oz.  per  tree  in  Malacca. 

Trees  Seventeen  Years  Old  :  Record  Yield. 

An  interesting  tapping  experiment  with  eight  17-year-old 
trees  growing  near  the  churchyard  at  Parit  Buntar,  in  the  Krian 
district  of  Perak,  gave  an  average  of  28J  lb.  of  dry  rubber  per  tree 
(Offic.  Rep.,  1908).  The  average  girth  of  the  trees  was  54-87  inches 
at  three  feet  from  the  ground,  and  they  have  been  growing  in  un- 
weeded  land  containing  lalang  and  other  grasses.  The  tapping  was 
done  on  alternate  days.  These  trees  appear  to  have  become 
quite  famous,  for  I  was  informed  later  (I.R.  J.,  Feb.  8th,  1909),  that 
one  of  the  trees,  then  18  years  old,  had  given  no  less  than  50  lb. 
of  rubber  in  twelve  months.  The  same  yield  is  also  reported  by 
Berkhout  (Tropenpfianzer,  July,  1910),  who  points  out  that, 
with  only  16  trees  to  each  acre,  the  yield  would  be  800  lb.  per  acre, 
per  annum.  This  appears  to  be  the  record  yield  from  any  Hevea 
tree  of  known  age  in  Malaya. 

Trees   Twenty-five  years   Old. 

At  a  recent  conference  of  Malay  planters,  Baxendale  reported 
a  very  high  yield  from  one  of  the  trees  now  growing  on  Gapis 
Estate,  Perak.  In  fifteen  days,  from  July  17th  to  July  31st,  1902, 
he  collected  6  J  lb.  of  rubber  from  three  small  cuts  close  to  the  base. 


PARA     RUBBER 


283 


After  he  left  Gapis,  Mr.  Salisbury  continued  the  tapping  spas- 
modically, and  the  total  result  in  35  days'  actual  tapping  (between 
July  17th  and  Sept.  i8th),  was  18  lb.  of  rubber.  The  tree  was  25 
years  old,  and  measured  89  inches  in  girth  at  one  yard  from  the 
ground. 

Yield   per   Acre   and   per  Tree. 

It  is  extremely  difficult  to  generalise  regarding  the  yield  per 
acre  and  per  tree  from  trees  of  known  age  in  Malaya,  owing  to  the 
variation  in  the  conditions  under  which  the  plants  are  grown,  the 
number  of  tapping  operations  performed,  and  the  bark  sections 
tapped  on  particular  trees.  If  the  abnormal  instances  are  deleted 
from  the  preceding  tables,  some  useful  data  may  be  formulated. 
An  attempt  has  been  made  to  do  this  in  the  following  table,  in 
which  actual  figures  of  yield  from  known  estates  are  used  : — 


Age 

in  Years. 

Per  Acre. 

Per  Tree. 

3  to     4 

50  to  100 

o'53  to  i"o6 

4  to     5 

70  to  136 

0-88  to  1-50 

5  to     6 

114  to  160 

I-2I  to  1-79 

6  to     7 

128  to  221 

160  to  247 

7  to     8 

240  to  319 

2-44  to  3-39 

8  to     9 

313  to  443 

3-09  to  4-17 

9  to   lO 

363  to  550 

3-90  to  445 

10  to   II 

396  to  630 

477  to  5-35 

ri  to  12 

450  to  758 

5'69  to  6'76 

In  the  above  compilation  it  is  clear,  since  figures  from  separate 
but  known  estates  are  used,  that  the  increase  does  not  exhibit  that 
regularity  which  one  would  anticipate.  The  figures  do  not 
include,  as  .already  mentioned,  those  of  extreme  cases,  but  have 
been  selected  to  show  the  average  variation  on  the  estates  already 
mentioned.  It  will  be  quite  obvious,  for  example,  that  a  yield 
of  6-76  lb.  per  tree  or  630  lb.  per  acre  is  not  the  maximum  quantity 
that  can  be  obtained.  It  is  also  clear  that  the  yield  per  tree  may 
be  at  the  maximum  when  that  per  acre  is  only  medium,  and 
vice-versa,  according  to  the  spacing  of  the  trees. 

It  is  only  necessary  to  Remind  those  who  may  use  this  table 
that  the  figures  represent  the  yields  from  trees  which,  after  all,  are 
still  young,  and  which  will  probably  have  to  suffer  repetitional 
stripping  of  bark  in  order  to  again  yield  as  in  the  past.  Whether 
the  trees  will  continue  to  thrive  under  this  treatment  remains  to 
be  seen.  The  yields  are  considerably  in  excess  of  those  recorded 
from  trees  in  the  Amazon  valley. 

Successive  Annual  Yields  from  Specified  Trees. 

There  are  few  estates  in  Malaya  which  have  been  in  full 
bearing  for  several  years.  Generally  a  number,  small  or  large, 
of  trees  has  been  added  to  the  tapping-round  at  irregular  intervals 
during  the  last  few  years,  thus  making  a  comparison  of  total 
annual  yields  from  each  estate  almost  valueless.  There  are, 
however,  one  or  two  instances  which  enable  us  to  note  the  progress 
in  yields  from  the  same  trees  in  successive  years. 


384 


PARA     RUBBER 


Number  of  trees  or 

Name. 

Years. 

Acres  Tapped. 

Yield. 

Vallambrosa 

1907-8 

930 

acres 

242  per  acre 

1908-9 

930 

,, 

293 

1909-10 

930 

,, 

399 

Federated  | 

1907-8 

27.483 

trees 

0-85  per  tree 

Selangor     1 

1908-9 

34.072 

,, 

^•75 

1909-10 

42.743 

,, 

267 

Consolidated  / 

1906 

11.345 

,, 

2-88 

Malay              1 

1907 

17.549 

,, 

362 

1908 

34,000 

328 

1909 

57.145 

,, 

3-77 

Linggi     . . 

1908 

79.714 

,, 

3-57 

1909 

151,796 

,, 

3-59 

1910 

285,000 

3"o8 

It  will  be  obvious  that  in  the  last-mentioned  companies  some 
of  the  extra  trees  brought  into  the  tapping-round  were  young 
specimens. 

Yields  from  F.M.S.  Co.'s  Estates. 

Some  valuable  results  have  been  kindly  placed  at  my  disposal 
by  the  Federated  Malay  States  Rubber  Co.,  Ltd.,  which  show  the 
yield  during  one  year  (ist  June,  1909,  to  31st  May,  1910)  from 
trees  which  had  been  previously  regularly  tapped  and  yielded 
large  crops. 

Estate     No.  i. 


Age  of  tapped 

Number  of 

Yield  per 

trees. 

tapped  trees,  tree  per  annum. 

1 1    years 

3,860 

9.18  lb 

10 

2,953 

9-32  ., 

6i        „ 

5.225 

3.00  ,, 

5ito6i       „ 

6,467 

2.92  ,, 

6i       ,. 

3,820 

2.64  „ 

6i       „ 

6,065 

2-47  .. 

6i       „ 

4.915 

^•43  .. 

5i^      .. 

7,020 

2.38  „ 

These  yields  are  exclusiv( 

;  of  earth 

rubber,  which  amoui 

an  average  of  o-io  lb.  per  t 

ree. 

ESTA 

TE  No.  2. 

Age  of  tapped 

Number  of 

Yield  per 

trees. 

tapped  trees,  tree  per  annum. 

6i  to    8J  yerrs    .  . 

4.807 

4-51  lb. 

6i  to  10 

3.802 

5"I9  ,, 

6ito    8i      „ 

"5.383 

3-23  .. 

6Jto    8J 

4.493 

3-l8., 

5jto    6J 

3,880 

2-47  .. 

6i     „        .. 

3,486 

241  .. 

During  1910  this  Compar 

y  obtained  the 

following  : — 

Number  of 

Yield  per       Number  of 

trees.                                    Age. 

tree. 

months  tapping 

66,170       .  .           .  .      5j  to  11 

years 

3-83 

12 

4,208       . .           .  .                  6i 

1-62 

II 

1,707       . .           .  .                10 

305 

IC 

8,489      .  .          . .     4    to    5 

,, 

1-24 

9 

14,285      ..          ..     3ito3f 

,, 

o"9i 

8 

PARA     RUBBER  283 

In  the  previous  year  the  following  crop  was  secured  : — 
17,148      ..         ..     94  to  lO^      ,,  550  12 

20,630      ..  ..     4|to    5I       ,,  103  6 

5.033       •  ■  •  •  5l        ..  o'50  4 

A  total  average  yield  of  i  -98.  lb.  per  tree  was  obtained  from 
63,886  trees,  varying  in  age  from  3  to  io|  years,  tapped  from  i  to 
12  months  during  the  year. 

Annual  Yields  from  Malaya. 

Having  dealt  with  the  yields  from  individual  trees  and  estates 
in  Malaya  it  is  now  necessary  to  see  what  returns  have  been 
obtained  from  the  country  as  a  whole  and  from  this  to  gain  some 
reUable  estimate  of  future  production  from  this  area.  The 
Director  of  Agriculture,  F.M.S.,  reports  the  following  crops  :— 


1906. 

1907. 

1908. 

1909. 

1910. 

lb. 

lb. 

lb. 

lb. 

lb. 

Selangor 

620,033 

1,131,086 

1,846,384 

3,676,451 

7.052.975 

Perak 

94,848 

272,804 

383.073 

1,060,543 

2,962,218 

Negri  Sembilan 

146,891 

586,864 

963,253 

1,346,499 

2,599.707 

Pahang 

— 

— 

— 

2.483 

Malacca 

12,000 

23.490 

52,980 

•      36,865 

599.918 

Province  Wellesley 

13.560 

82,131 

92 '600 

293.516 

445,659 

Johore 

47.724 

182,495 

201,632 

327.635 

664,352 

Kelantan  and  Kedah 

— 

41.551 

Total    .. 

935.056 

2,278,870 

3.539,922 

6,741,509 

14,368,863 

If  we  consider  the  Federated  Malay  States  alone  we  find  that 
the  total  annual  yields  for  the  past  few  years  have  been :  1906, 
935.056  lb.;  1907,  2,278,870  lb. ;  1908,  3,539,922  lb. ;  1909, 
6,741,509  lb. ;  1910,  14,368,863  lb  These  are  the  figures  of 
production  issued  by  the  Agricultural  Department.  The  figures 
of  exports  from  the  Federated  Malay  States  as  given  by  the 
Federated  Malay  States  Information  Agency  are  generally  lower ; 
for  1911  the  amount  given  was  19,695,330  lb. 

Trees  Tapped  in  1906. 

The  productions  during  1906  for  Malacca  and  Province 
Wellesley  are  only  approximate  ;  those  from  the  latter  include 
rubber  from  nine  estates  in  Singapore  and  six  in  Penang.  The 
total  number  of  trees  tapped,  during  that  year,  was  441,488  in 
F.M.S.,  27,076  in  the  Straits  Settlements,  and  48,350  in  Johore, 
making  a  grand  total  of  516,914.  Many  of  the  tapped  trees 
in  the  F.M.S.  were  10  years  old  and  a  few  even  20  years  old.  The 
average  3deld,  per  tree,  for  1906  was,  therefore,  li  lb.  of  dry 
rubber. 

Trees  Tapped  in  1907. 

In  this  year  1,300,227  trees  were  tapped  in  the  F.M.S. ,  Straits 
Settlements,  and  Johore.  The  average  jdeld  per  tree  was  i  lb. 
12  oz.  In  the  ^^.M.S.  Selangor  had  a  very  long  lead  with  regard 
to  the  number  of  trees  being  tapped,  having  772,656,  against 


286  PARA     RUBBER 

240,401  in  Negri  Sembilan,  and  132,556  in  Perak.  The  average 
yield,  however,  was  higher  in  Negri  Sembilan  and  Perak,  being 
2  lb.  7  oz.  and  2  lb.  i  oz.  respectively,  against  i  lb.  7^  oz.  in 
Selangor.  This,  however,  is  not  much  to  go  by,  as  we  have  no 
returns  of  the  ages  of  the  trees. 

Trees  Tapped  in  1908. 
The  average  yield  per  tapped  tree  all  over  the  peninsula 
rose  from  i  lb.  12  oz.  in  1907  to  i  lb.  I5f  oz.  in  1908,  an  increase  of 
II  per  cent.  Considering  that  the  majority  of  the  trees  tapped 
were  in  their  first  year  of  bearing,  this  is  a  most  encouraging 
figure.  The  average  yield  in  Negri  Sembilan,  during  1908, 
amounted  to  3  lb.  2^  oz.,  which,  being  the  average  of  nearly  one 
million  trees,  is  an  extraordinarily  high  figure.  This  state  had 
much  higher  yields  per  tree,  because  the  proportion  of  trees  in 
their  first  tapping  period  was  much  less  than  in  the  other  States, 
but  this  high  figure  is  interesting  as  pointing  to  the  averages 
which  may  be  expected  from  trees  after  two  or  three  years'  tapping. 
The  yield  for  1908  was  obtained  from  a  total  of  1,954,090  trees, 
i,i72',383  of  these  being  in  Selangor,  251,613  in  Perak,  306,376 
in  Negri  Sembilan,  56,846  in  Malacca,  65,100  in  Province  Wellesley, 
and  101,772  in  Johore. 

Yield  from  1909  to  1911. 

The  output  of  rubber  during  1909  from  Malaya  was  6,741,509 
lb.,  and  was  succeeded  by  a  crop  of  14,368,863  lb.  in  1910.  The 
Federated  Malay  States  alone  gave  in  1910  four  times  the  crop 
for  1908  and  100  per  cent,  above  that  for  1909.  The  output 
figures  given  above  for  the  F.M.S.  is  about  400,000  lb.  in  excess 
of  those  returned  by  the  Commissioner  of  Trade  and  Customs. 
This  difference,  the  Director  of  Agriculture  states,  is  largely 
represented  by  rubber  on  hand  on  the  plantations.  As  stated 
above,  the  exports  in  1911 ,  from  the  F.^M.S.  alone,  were 
19.695,330  lb.  The  total  for  the  whole  of  Malaya  promises,  at 
the  date  of  writing,  to  be  over  23,060,000  lb. 


CHAPTER  XVII. 

YIELDS  IN    CEYLON    AND    SOUTH    INDIA. 

It  is  quite  manifest  from  a  cdmparison  of  the  available  figures 
that,  up  to  the  present,  Ceylon  takes  a  second  place,  compared  with 
Malaya,  in  point  of  annual  yield  from  young  trees  and  from 
definite  acreages  of  known  age,  though  the  recorded  yields 
from  old  trees  in  Ceylon  are  exceptionally  high.  It  is  freely 
admitted  that  the  soil  or  climatic  conditions  in  Ceylon  are  less 
favourable,  in  the  first  few  years,  to  the  growth  of  Hevea  hrasiliensis. 
Whether  the  moist  conditions  in  Malaya  will  prove  to  be  so 
beneficial  to  old  trees  as  the  comparatively  dry  environment 
in  Ceylon  remains  to  be  proved.  It  must  be  pointed  out  that, 
though  rubber  in  Ceylon  may,  in  the  first  few  years,  only  have 
been  produced  at  the  rate  of  150  lb.  per  acre,  per  annum,  other 
products  on  the  same  land  have  returned  good  crops  during  the 
same  period. 

First  Recorded  Yields  from  Ceylon. 

The  first  series  of  reliable  yields,  from  cultivated  trees,  were 
those  obtained  at  Henaratgoda  from  1888  to  1896.  One  tree  at 
Henaratgoda  was  lightly  tapped  every  second  year,  and  gave 
for  nine  years  an  average  annual  yield  of  i|  lb.  of  dry  rubber  : — 

27f  oz.  in  1888  51  oz.  in  1894 

42  oz.  in  1890  48^  oz.  in  i8g6 

5  oz.  in  1892 

This  tree  was  twelve  years  old  when  first  tapped,  and  the 
annual  yield  of  i^  lb.  was  from  the  12th  to  the  20th  year  of  the 
tree's  life.  The  method  of  tapping  consisted  of  scraping  off  the 
rough  outer  bark  and  making  numerous  V-shaped  incisions  to  a 
height  of  about  five  feet.  The  tree  had  a  circumference  of  50^ 
inches  and  was  growing  with  other  trees  of  nearly  equal  size, 
distanced  30  feet  apart. 

Yields  From  Young  Trees. 

There  are  very  few,  if  any,  estates  in  Ceylon  where  the  trees 
are  sufficiently  large  to  permit  of  tapping  under  four  years  of  age. 
In  this  respect  there  is  a  striking  difference  with  Malaya,  where 
tapping  is  often  started  as  soon  as  the  trees  are  three  years  old. 
Purely  as  an  experiment,  some  two-year-old  trees  were  tapped  in 
Kalutura,  but  the  yield  therefrom  was  insignificant.  In  that 
district  quite  a  number  of  trees,  tapped  when  four  years  old,  have 
given  over  100  lb.  per  acre  in  the  first  twelve  months.  A  yield 
of  I  lb.  per  tree  is  recorded  from  2,119  trees,  four  years  old,  on 


288  PARA     RUBBER 

•one  estate,  and  of  0-63  lb.  per  tree  from  747  trees  of  the  same  age 
on  Mahawale.  On  Rayigam,  6,000  trees,  four  to  five  years  old, 
gave  -J  lb.  of  rubber  each,  and  a  further  1,500  yielded  0-41  lb. 
each.  Light  tapping  of  young  trees  on  a  well-known  Kalutura 
property  gave  1-72  lb.  of  rubber  per  tree. 

Yields  from  Old  Trees. 

At  one  time  a  yield  of  two  to  three  lb.  per  tree  from  eight 
to  eleven-year-old  trees  on  KepitigaUa  estate  was  considered 
^ood.  One  tree  on  Elpitiya,  46  in.  in  circumference  and  eleven 
years  old,  gave  16  lb.  of  rubber  when  tapped  on  the  spiral  system. 
The  Elpitiya  tree  had  a  circumference  of  46  inches  ;  the  tapping 
was  commenced  in  October,  1904  ;  the  tree  was  rested  in  Novem- 
ber, tapped  again  in  December,  rested  in  January,  1905,  and 
continuously  tapped  from  February  to  June,  1905.  Tapping 
■was  recommenced  in  September,  1905.  This  tree  appeared  quite 
healthy  in  April,  1908. 

Individual  trees  of  unknown  age  (probably  20  to  25  years) 
on  CuUoden  estate,  gave  10,  18,  23,  and  25  lb.  of  rubber  in  twelve 
months,  tapped  on  various  systems.  These  trees  gave  an  average 
of  18  lb.  per  tree,  per  annum,  for  four  years. 

Several  trees  at  Peradeniya,  when  29  years  old,  gave  6f  lb. 
each  in  eight  months,  and  were  still  in  good  condition.  Others 
on  the  same  site  gave  3  lb.  each  in  twelve  weeks. 

Upon  the  Imboolpitiya  estate  in  the  Ambagamuwa  district 
at  an  elevation  of  2,000  feet,  several  28-year-old  trees  were  tapped 
from  i8th  December,  1905,  to  i8th  March,  1906,  and  therefore 
during  three  very  dry  months.  One  tree  tapped  17  times  gave 
3  lb.  7  oz.  of  dry  rubber ;  two  others,  tapped  21  times,  gave  11  lb. 
7  oz. 

80  LB.  PER  Tree,  per  Annum. 

The  largest  yield  appears  to  have  been  obtained  from  the 
old  Henaratgoda  trees  during  1909  and  1910.  During  that  period 
the  largest  tree  gave  160  lb.,  or  at  the  rate  of  80  lb.  per  annum  : 
the  record,  probably,  for  the  world.  This,  from  a  tree  planted 
in  1876,  gives  one  some  idea  of  what  yield  can  be  obtained  from 
Hevea  on  very  poor  soil  at  thirty-five  years  of  age.  It  is  only 
fair  to  add  that  the  trees  at  Henaratgoda  have  never  been  syste 
matically  tapped  and  were  not  until  a  few  years  ago  even  ex- 
perimentally operated  upon. 

Some  trees  at  Henaratgoda,  over  20  years  old,  tapped  on  the 
full  herring-bone  system  with  knife  and  pricker,  have  yielded  at  the 
(computed)  rate  of  from  885  lb.  to  257  lb.  per  acre  per  year  when 
tapped  in  frequency  from  daily  to  seven-day  tapping.  The 
system  employed  was  not  one  recommended  for  estate  work. 


PARA     RUBBER 


289 


Trees  4  to  6  Years  Old. 

There  are  fewer  Hevea  estates  in  Ceylon  with  trees  of  the 
above  age  which  have  been  systematically  tapped  than  in  Malaya. 
The  following  statistics  give  some  idea  of  what  has  been  obtained: — 


Name. 

Yield  in  lb, 

Remarks. 

Hevea  Trees. 

Per 

Per 

Age. 

Number. 

Acres. 

,  Total. 

tree. 

acre. 

Mahawale  . . 

4 

747 

4 

470 

063 

117 

R.  Plantations  of 

4) 

2,119 

1,061 

0-50 

Kalutara 

5.064 

— 

3.093 

o-6i 

— 

Rayigam    . . 

4-5 

6,000 

— 

2,989 

0-50 

— 

In  10  months 

i> 

4-5 

1,500 

— 

621 

0-41 

— 

,,  10        „ 

PelmaduUa 

4i-54 

42.777 

476 

15.075 

0-35 

31 

.,  11 

Bedewella 

4-6 

2.538 

288 

2,164 

0-85 

89 

„     9 

The  above  figures  show  a  yield  per  tree,  from  4-to-5-year-old 
trees,  of  from  0-41  to  0-85  lb.  and  a  maximum  of  117I  lb.  per  acre. 
Most  of  the  trees  were  tapped  on  the  half-herring-bone  system 
for  9  to  12  months  in  the  year.  The  yield  per  tree,  from  trees 
4  years  old,  varies  from  0-50  to  0-63  lb.  On  Penrith  estate  8,726 
trees  varying  in  age  from  4  to  9  years,  planted  over  43J  acres,  gave 
in  II  months'  tapping  9,725  lb.  of  dry  rubber.  This  was  at  the 
rate  of  i-ii  lb.  per  tree  or  224  lb.  per  acre  for  the  tapping  period. 


Trees  5  to  7 

Years 

Old. 

The  yield  from  trees  averaging  six  years  shows  a  very  slight 

increase  over  those  just  recorded. 

Name. 

Hevea  Trees. 

Yield  in  lb. 

Age.       Number. 

Acres. 

Total. 

Per  tree. 

Per  acre. 

Rubber  Planters  of 

Kalutara 

5           11.252 

— 

8.934 

079 

75 

Kalutara    Rubber 

Co.  of  Ceylon  . . 

56           34.800 

— 

27.835 

o-8o 

— 

Grand  Central     . . 

5               — 

1,182 

— 

64 

Mahawale 

5             2,260 

II 

1,827 

o-8o 

166 

Narthupana 

5             8,100 

67 

7,000 

0-86 

104 

Mahawale 

5-6            11.256 

56 

9,428 

0-84 

168 

Kepitigalla 

5-7            18.563 

8,074 

0-43 

— 

The  Kepitigalla  trees  were  tapped  for  8  and  those  on  Narthu- 
pana 9  months.  The  yield  from  5-year-old  trees  varies  very 
little,  the  return  being  from  0-79  to  o-86  lb.  per  tree.  The  yield  per 
acre,  however,  varies  from  75!  to  166  lb.  per  acre.  This  is,  there- 
fore, a  slight  increase  compared  with  4-to-6-year-old  trees. 

On  Suduganga  estate,  Matale,  10,856  trees  varying  in  age 
from  5  to  over  11  years  gave  an  average  yield  of  0-92  lb.  These 
were  scattered  through  cacao  and  tea.  The  General  Ceylon 
Rubber  and  Tea  Estates  also  record  that  from  3,672  trees,  5  to  8 
years  old,  and  scattered  over  18  acres,  a  return  of  70  lb.  per  acre  or 
0-35  lb.  per  tree  was  obtained  in  eleven  months'  tapping. 

Trees  6  to  7  Years  Old. 

Quite  a  large  number  of  records  are  available  showiDg  the 
3delds  from  trees  once  they  have  reached  their  sixth  year 


ago 


PARA     RUBBER 


Name. 

Yield  in 

lb.             Remarks. 

Hevea  Trees. 

Per 

Per 

Age. 

Number. 

Acres 

Total. 

tree. 

acre. 

General  Ceylon 

.      6 

5.924 

53 

10.574 

1-78 

198 

Rubber  Plantations 

6 

2,000 

1,481 

075 

— 

Narthupana 

.      6 

13,000 

67 

26,000 

2-00 

388 

Deviturai 

.      6 

6,727 

6,779 

I-OI 

—  In  9  months. 

Grand  Central 

.      6 

427 



105   In  6  months. 

Deviturai 

■      7 

7.215 

6,960 

0-96 

—  In  9  months. 

Grand  Central 

.     7 

249 

— 



200  In  6  months. 

Kepitigalla 

.    7  to 

10,816 

17,200 

1-59 

—  In  10  months 

over  10 

The  yield  from  6-year-old  trees  varies  from  I'Oi  to  2  lb.  per 
tree,  and  105  to  388  lb.  per  acre.  It  will  also  be  noted  that  the 
yield  from  7-year-old  trees  is  given  as  200  lb.  per  acre  (Grand 
Central),  and  0-96  lb.  per  tree  (Deviturai),  though  tapping  was  only 
carried  on  for  6  and  9  months  respectively. 

Lochnagar  Produce  Company  report,  from  6,200  trees,  5  to  9 
years  old,  7,645  lb.  of  rubber,  or  an  average  of  1-23  lb.  per  tree, 
from  areas  interplanted  with  cacao  and  tea. 

Doranakande  obtained  an  average  return  of  1-27  lb.,  per  tree, 
from  23,812  trees,  5  to  17  years  old.  Suduganga  cropped  0-97  lb. 
per  tree  from  6,503  trees,  6  to  over  11  years  old,  scattered  through 
cacao  and  tea.  Glendon  secured,  from  43,000  trees,  6  to  16  years 
old,  an  average  of  1-25  lb.  per  tree  ;  Passara  Group  yielded  2  lb.  per 
tree,  from  370  trees,  6  to  13  years  old. 


Trees  7  to  9  Years  Old. 

In  this  group  there  is  still  a  variation  of  some  importance,, 
though  it  will  be  noted  that  the  yield  per  tree,  on  estates  the 
majority  of  which  are  planted  with  200  trees  per  acre,  is  between 
I  to  2  lb. 


Hevea  Trees. 

Yield  in  Ih 

. 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree. 

Per  acre 

Suduganga 

7-10 

3.370 

— 

4,270 

1-27 

— 

Taldua 

7-8 

3.500 

— 

About  2,000    OS? 



Southern  Ceylon 

7-9 

577 

— 

614 

1-07 



Dangan    . . 

7i-9i 

7,700 

— 

8,378 

I '09 

— 

,. 

8 

4,400 

— 

3.205 

073 

— 

., 

H 

5.175 

— 

5,216 

I'OI 

153 

Deviturai 

8 

2,000 

— 

2,996 

15 

Lochnagar 

.       8 

5,200 

150 

6,077 

117 

40 

Grand  Central     . 

8 

— 

112 

-=34 

Deviturai 

9 

5.290 



9.380 

1-77 

Kepitigalla 

.      8-15 

10,000 

— 

30,000 

3 

— 

The  Deviturai  trees  were  tapped  for  9,   and   those  of  the 
Grand  Central  Estate  6  months  only. 


Trees  9  to  ii  Years  Old. 

There  are  very  few  trees  in  Ceylon  from  9  years  and  upwards, 
but  the  following  statistics  are  of  some  interest : — 


PARA     RUBBER 


291 


Hevea  Trees. 

Yield  in  lb. 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per  tree.  Per  acre. 

Kepitigalla 

9-10 

400 

50 

339 

085 

6oi 

t>                        -  •                 s 

lO-II 

3.370 

303 

5,000 

1-48 

— 

,, 

lO-II 

400 

50 

382 

o'96 

— 

Suduganga 

10 

3.370 

— 

5,000 

149 

— 

„ 

II 

3.370 

— 

4.665 

139 

— 

Kepitigalla 

II 

— 

— 

— 

3\ 

— 

A  Matale  Estate 

II 

499 

— . 

1.596 

3 

— 

South  of  Ceylon 

II 

255 

— 

5i 

— 

Name. 

He 

i^ea  Trees. 

Age. 

Number. 

Igalkande    . 

12 

1616 

Igalkande    . 

13 

1616 

Igalkande 

14 

1616 

Deviturai 

15 

248 

The  trees  on  the  Matale  estate  were  tapped  for  seven  months 
only.  The  yield  given  in  the  first  three  series,  from  old  trees  on 
Kepitigalla,  is  low  on  account  of  bad  tapping  in  previous  years. 
The  other  yields  are  by  no  means  equal  to  those  from  similar- 
aged  trees  elsewhere. 

Trees  12  to  15  Years  old. 

The  following  yields  are  nearly  all  taken  from  the  records  of 
one  company  : — 

Yield  in  lb. 

Acres.        Total.        Per  tree.  Per  acre. 

6  2813  I-74'  469 

6  2433  1-51  405 

6  2679  1-66  446 

—  905  3-65  — 

The  trees  on  Deviturai  were  15  years  and  over,  but  were  only 
tapped  for  nine  months.  The  soil  in  this  particular  area  is  by  no 
means  rich,  and  I  understand  that  many  of  the  old  trees  were  used 
for  experimental  work  and  the  training  of  tapping  coolies.  It 
will  also  be  observed  that  the  trees  were  closely  planted,  and  that 
the  jaeld  per  acre  was  comparatively  large  for  Ceylon. 

Yields    Per   Acre  and   Per   Tree. 

The  same  difficulties  have  been  experienced  in  compiling  a 
statement  of  jdelds  per  acre  and  per  tree  for  Ceylon  as  were  noted 
when  dealing  with  this  subject  in  connection  with  Malaya.  In 
the  following  table  figures  have,  as  far  as  possible,  been  taken 
from  the  records  of  estates.  These  do  not  necessarily  give  the 
total  range,  but  the  more  probable  averages,  from  specified  estates, 
after  elimination  of  exceptional  returns  : — 


.\ge  in  years. 

Yield  per  acre. 

Yield  per  tree. 

4  to     6 

31  to  1171b. 

041  to  0-63  lb 

5  to     7 

64  to  166   ,, 

060  to  0  86  ,, 

6  to     7 

105  to  200   ,, 

0-75  to  1-59  „ 

7  to     9 

153  to  234   „ 

I  01  to  1-77  ,, 

9  to   II 

— 

148  to  3-00  ,, 

12  to  15 

405  to  469   „ 

174  to  365   „ 

A  point  of  some  importance  which  is  brought  out  in  the 
above  table  is  that  though  the  yield  per  tree  compares  unfavourably 
with  that  in  Malaya,  the  outturn  per  acre  is  by  no  means  in- 
significant once  tapping  operations  are  in  full  swing.  This  is 
explained  by  the  fact  that  the  areas  at  present  being  tapped  in 
Ceylon  are  very  closely  planted. 


292  PARA     RUBBER 

Past  Yields  Pee  Acre  from  Ceylon. 

It  is  now  convenient  to  determine  the  yield  per  acre  from 
planted  acreages  in  Ceylon  which  have  been  brought  to  the  pro- 
ductive stage.  The  foregoing  statistics  justify  one  in  assuming 
that  rubber  acreages  in  Ceylon  may  be  tapped  in  their  fifth  year. 

In  1901  there  were  2,469  acres  planted  in  rubber,  alone  and 
with  other  products  ;  this  area,  along  with  some  younger  rubber, 
produced  415  tons  in  1908,  which  is  at  the  rate  of  i-68  tons  per 
ten  acres.  By  the  year  1902,  the  area  was  3,356  acres,  from 
which  in  1909  were  turned  out  679  tons,  the  rate  per  ten  acres 
being  2-02  tons.  Great  progress  in  planting  had  been  made  by  the 
year  following,  1903,  with  11,630  acres,  only  a  part  of  which  can 
have  been  in  bearing  in  1910,  when  1,499  tons  were  produced, 
that  is,  as  much  as  1-29  tons  per  ten  acres. 

If  the  yields  from  acreages  six  years  old  are  considered, 
they  will  be  found  to  be  almost  as  much  below  a  ,  those  for  seven 
years  are  above,  one  ton  per  ten  acres.  The  average  yield  of  one 
ton  per  ten  acres  appears  to  have  been  obtainei  waen  the  trees 
were  about  6^  years  old,  taking  the  island  as  a  whole. 

Yields   from    Ceylon    Districts    and    Estates. 
Matale   District. 

In  the  Matale  District  there  are  estates  where  an  average 
yield  of  j  lb.  of  dry  rubber  per  tree  from  5,000  trees  has  been 
secured  in  one  month's  tapping.  The  average  circumference  of 
these  trees  was  35  inches  a  yard  from  the  ground. 

On  another  property  a  yield  of  32  lb.  of  rubber  per  tree 
has  been  obtained  from  499  trees  in  seven  months'  tapping. 
Another  estate,  in  the  same  district,  has  obtained  an  average 
yield  of  3^  lb.  of  dry  rubber  per  tree  from  311  trees  in  one  year. 
The  age  of  these  trees  varied  from  10  to  15  years,  and  the  trees 
varied  in  circumference  from  30  to  70  inches  at  a  yard  from  the 
ground.  They  were  tapped  on  the  full  herring-bone  system ; 
the  tapping  area  covered  half  the  tree  and  extended  from  the 
base  to  a  height  of  seven  feet.  The  tapping  was  done  very 
carefully,  a  distance  of  seven  feet  being  worked  through  in  240 
days  of  continuous  tapping.  The  yield  from  these  particular 
trees  wiU  probably  be  increased  by  a  change  in  the  method  of 
tapping  and  tapping  implements. 

On  a  third  Matale  estate  the  Hevea  trees  are  planted 
among  cacao.  The  cacao  is  planted  12  by  12  feet  and  the 
rubber  through  alternate  lines  of  cacao  24  by  12  feet.  By  the 
V  method  of  tapping  a  yield  of  3  lb.  of  dry  rubber  from  each  of 
10,000  trees  was  expected,  the  trees  being  8  to  15  years  old.  On 
this  estate  several  encouraging  experiments  in  tapping  from  6 
feet  upwards  to  a  height  of  15  feet  have  been  made,  light  ladders 
being  used  for  the  purpose. 

The  Province  of  Uva. 

The  most  successful  results  at  high  elevations  in  Ceylon  have 
probably  been  obtained  in  the  Province  of  Uva.     On  Passara 


PARA     RUBBER.  293 

Group  estate,  Hevea  brasiliensis  is  being  cultivated  up  to  and  over 
3,000  feet  above  sea-level.  The  trees  are  of  various  ages,  and  one 
specimen,  13  years  old,  measured  54  inches  in  circumference  a 
yard  from  the  ground,  and  60  to  70  feet  in  height,  though  growing 
at  an  elevation  of  about  2,600  feet.  Tapping  has  been  carried  on 
with  promising  results  up  to  2,800  feet.  From  the  trees  at  an 
elevation  of  2,600  feet,  varying  in  age  from  7  to  13  years,  an 
average  yield  of  2  lb.  of  dry  rubber  per  tree  was  obtained  during 
1905.     These  results  are  of  considerable  interest  and  importance. 

A  considerable  amount  of  Hevea  has  been  planted  in  the 
BaduUa,  Passara,  Monaragala,  and  Bibile  Districts  ;  and  in  many 
cases  the  altitude  is  considerably  over  2,000  feet. 

Kelani,  Kalutara,  Ambalangoda,  Rayigam,   &c. 

In  the  South  of  Ceylon  equally  good  and  often  better  results 
have  been  obtained.  On  one  estate  8,731  trees,  having  a  minimum 
circumference  of  20  inches,  gave  in  one  year  an  average  of  1-72  lb. 
of  dry  rubber  per  tree.  On  the  same  property  an  average  of  2  lb. 
per  tree  from  each  of  about  10,000  trees  was  expected  during  1906. 

A  section  of  another  rubber  property  in  the  South  of  Ceylon 
gave,  from  eleven-year-old  trees,  the  average  circumference  of 
which  was  30  inches  only,  no  less  than  5^  lb.  of  dry  rubber  from 
each  of  255  trees.  The  eight  largest  trees  on  this  property  yielded 
no  less  than  16  lb.  of  dry  rubber  each  in  twelve  months  ;  the 
newly-formed  cortex  has  been  tapped  again,  and  a  good  flow  of 
latex  secured.  These  results  have  been  obtained  by  the  half  or 
full-spiral  system  of  tapping. 

A  well-known  old  Kalutara  company  having  its  Hevea  trees 
mainly  planted  among  tea  records  the  following  :• — 


Hevea 

Trees. 

Yield    in   lb. 

Fumber. 

Acres. 

Total. 

Per  tree. 

Per  acre. 

8,368 

63 

13.655 

1-63 

217 

13.330 

63 

23.803 

1-79 

378 

17,610 

83 

36,520 

2  08 

440 

28,580 

150 

57.561 

201 

384 

39,912 

189 

87.779 

2  20 

464 

These  trees  were  from  four  to  ten  years  old,  and  the  results 
show  that  even  in  Ceylon  a  yield  approximating  to  one  ton  per 
five  acres  can  be  obtained  over  a  large  acreage  of  trees  which  have 
passed  their  infancy. 

The  quantity  of  rubber  harvested  during  1905  in  Kalutara 
district\was  101-978  lb.  from  88,667  trees,  which  shows  an  average 
of  about  1-15  per  tree.  A  large  number  of  these  trees,  about  43 
per  cent.,  were  tapped  for  the  first  time,  but  as  nearly  aU  the 
older  trees  in  the  district  were  planted  in  selected  spots  and  at 
great  distances,  the  Kalutara  Association  did  not,  at  that  time, 
expect  to  see  any  increase  in  the  5deld  per  tree  for  a  considerable 
number  of  years.  This  district  is  one  of  the  most  successful  in 
Ceylon,  and  the  returns  obtained  by  the  most  advanced  estates 
within  its  boundaries  during  1910  have  revived  confidence  among 
planters  in  the  island. 


294  PARA     RUBBER 

Yields  on   Gikiyanakanda   Estate. 

The  results  obtained  on  the  above  estate  for  1905  are  of 
importance  as  showing  reliable  details  of  jdeld  and  dimensions  of 
trees.  During  the  year,  5,598  trees  were  tapped  ;  of  these,  2,207 
had  been  previously  tapped.  Between  January  and  March  1,346 
new  trees  were  operated  on  for  the  first  time,  and  again  between 
July  and  October  other  2,045  trees  were  tapped  for  the  first  time. 
The  minimum  girth  of  the  trees,  which  were  tapped  for  the  first 
time,  was  20  inches  at  a  yard  from  the  ground,  and  the  census  at 
the  end  of  the  year  showed  that  3,811  out  of  the  5,598  had  a 
circumference  of  24  inches  or  over.  The  trees  were  tapped  on  the 
full  herring-bone  system,  each  tree  being  tapped  every  alternate 
day.  The  paring  operations  were  done  carefully,  the  width  of 
excised  bark  being  slightly  less  than  one  inch  per  month.  The 
total  quantity  of  rubber  from  the  5,598  trees,  some  of  which  were 
tapped  from  January  onwards,  others  only  from  October,  was 
7,592  lb.,  or  1-34  lb.  per  tree. 

Increase  in  Yield  from  Ceylon  Estates. 

The  yields  obtained  from  some  estates  during  the  past  few 
years  are  small  but  show  a  gradual  increase  from  the  same  pro- 
perties as  the  tapped  trees  get  older  and  more  young  ones  attain  a 
tappable  size  and  age.  The  gradual  increase  is  exemplified  in  the 
yields,  per  tree,  obtained  on  Gikiyanakanda,  Neboda,  Ceylon, 
according  to  the  information  kindly  supplied  to  me  by  Mr.  Gol- 
ledge  :  1903,  0-59  lb.  ;  1904,  076  lb.  ;  1905,  1-32  lb.  ;  1906, 
178  lb.  ;  and  1907,  i-86  lb. 

Rosehaugh  Tea  and  Rubber  Co. — The  yield  of  rubber  for  the 
twelve  months  ended  31st  December,  1910,  was  410,707  lb. 
For  the  past  three  years  the  yield  has  been  :  1908,  223,859  lb.  ; 
1909,  291,354  lb.  ;  and  in  1910,  410,707  lb. 

Ceylon  Tea  Plantations  Co. — The  jaeld  during  1910  was 
118,626  lb.  from  140,823  trees,  as  against  54,548  lb.  for  1909. 
Many  of  the  trees  tapped  in  1910  were  operated  upon  for  the  first 
time.     The  yield  in  1911  was  240,120  lb. 

Yatiyantota  {Ceylon)  Tea  Co. — The  quantity  of  rubber  secured 
during  1910  was  39,702  lb.,  as  compared  with  14,488  lb.  in  1909. 
The  yield  from  the  trees  in  the  old  487  acres  of  Polatagama  was 
16,366  lb.,  as  compared  with  7,330  lb.  in  1909.  The  balance  of 
23,336  lb.  was  obtained  from  interplanted  trees  in  the  tea  area. 
The  yield  in  1911   was  84,901  lb. 

The  crop  from  the  P.P.K.  (Ceylon)  Rubber  Estate  was  45,474 
in  1909  and  62,500  in  1910.  An  increase  from  964  to  2,670  was 
also  shown  for  the  same  years  in  the  returns  from  the  Haydella 
Tea  and  Rubber  Estates. 

The  Lavant  Rubber  and  Tea  Company  produced  6,000  lb. 
in  1909,  19,358  lb.  in  1910,  and  62,240  lb.  in  1911 ;  the  estimate 
for  1912  is  100,000  lb. 

The  Panawatte  Rubber  Company  obtained  89,204  lb.  in 
1910  and  181,529  lb.  in  1911. 


PARA     RUBBER  295 

The -Pelmadulla  Rubber  Company  similarly  showed  a  large 
increase,  the  crop  in  1910  being  17,547  and  in  1911,  74,556  lb. 

The  Eastern  Produce  Company  obtained  121,111  lb.  in  1910 
and  155,280  lb.  in  1911.  There  are  many  other  estates  in  Ceylon 
which  have  shown  a  conspicuous  increase  in  crop  during  the  past 
few  years,  but  the  above  references  will  be  sufficient  to  emphasize 
the  point  under  consideration. 

Prospective  Increases  from  Ceylon  Properties. 

There  are  many  estates  in  Ceylon  which  in  the  past  have  not 
had  large  crops  of  rubber,  but  which  in  virtue  of  their  large  acreages 
are  destined  to  play  an  important  part  in  the  future  of  rubber 
crops  from  that  island. 

Among  these  may  be  mentioned  Woodend,  which  gave  7,202 
lb.  in  1910  from  a  small  number  of  old  trees  ;  Panawal,  which 
yielded  11,005  lb-  ;  and  Pantiya,  which  harvested  23,918  lb.  in 
the  same  period.  On  the  property  of  the  Ceylon  (Para)  Rubber 
Co.,  tapping  operations  were  commenced  in  July,  igio.  The 
trees  were  very  lightly  treated  in  the  early  stages,  and  it  was  not 
until  the  closing  months  of  the  year  that  rubber  was  harvested  in 
any  appreciable  quantity.     The  total  crop  was  11,567  lb. 

The  Grand  Central  (Ceylon)  Rubber  Estates  recorded  for 
1910  a  rubber  crop  from  the  Urumiwella,  Nakiadeniya,  Duram- 
pitiya,  Atale,  Pallegama  and  Arandara  Estates  of  140,367  lb. 
This  Company  possesses,  in  addition  to  large  acreages  of  young 
rubber,  788^  acres  planted  1900-1904  and  1,182^  acres  planted 
during  1905. 

The  Kintyre  Tea  Estates  Co.  during  the  year  1910-1911 
harvested  40,108  lb.  This  company  possesses  139  J  acres  of  Hevea 
planted  from  1902  to  1905,  in  addition  to  some  among  tea  and 
large  areas  of  rubber  planted  after  1905. 

Yields  in  South  India. 

The  acreage  in  bearing  in  South  India  is  small,  and  there 
are  but  few  records  available  of  average  crops  from  estates  in  that 
part  of  the  world. 

The  Travancore  Rubber  Co.,  obtained  in  1910,  from  20,000 
trees,  4  to  5  years  old,  a  crop  of  6,385  lb.  The  trees  were  very 
lightly  tapped,  and  yielded  an  average  of  0-32  lb.  each,  or  at  the 
rate  of  32  lb.  per  acre  over  the  whole  200  acres. 

Mooply  Valley  in  1910  harvested  6,600  lb.  from  trees  planted 
over  45  acres  in  1905.  This  was  obtained  during  a  few  months' 
tapping  only. 

The  Rani  Travancore  Rubber  Co.  obtained  in  1910,  from 
79,800  trees,  then  5  to  6  years  old,  41,983  lb.  of  rubber,  equivalent 
to  0-53  lb.  per  tree.  It  should  be  pointed  out  that  a  large  number 
of  the  trees  only  reached  the  tapping  stage  towards  the  end  of  the 
year. 

The  Periyar  Rubber  Co.  secured  in  1908,  from  238  acres  of 
Hevea,  then  six  years  old,  11,340  lb.  Since  that  date  the  yield 
per  acre  has  been  increased  considerably. 


296  PARA    RUBBER 

Old  Trees  in  Malabar. 
Some  old  trees  planted  between  1883  and  1885  at  Poonur  in 
Malabar,  were  recently  tapped  (T.A.,  March,  1910).  They  were 
planted  135  trees  per  acre,  and  many  of  them  measured  seven 
feet  at  over  three  feet  from  the  ground.  During  several  months' 
tapping,  the  trees  are  said  to  have  yielded  at  the  rate  of  i  lb.  of  dry 
rubber  per  tree,  per  month,  a  cooly  collecting  about  3  J  lb.  per  day. 

Yields    at    High    Altitudes. 

On  Hawthorne  Estate,  Shevaroy  Hills,  the  rubber  trees  are 
growing  among  coffee,  at  an  elevation  of  3,000  to  3,500  feet,  and 
in  a  cMmate  having  only  about  50  inches  of  rain  annually.  The 
photographs  of  the  rubber  on  this  estate  show  fairly  good  growth, 
most  of  the  trees  having  been  allowed  to  produce  tall  and  slender 
stems.  Early  in  1906,  91  Hevea  rubber  trees,  twelve  of  which  were 
seven  years  old  and  the  rest  five  and  six  years,  were  tapped,  and  an 
average  j^ield  of  ^  lb.  of  dry  clean  rubber  per  tree  for  one  month 
was  obtained.  In  conjunction  with  this  it  must  be  remembered 
that  at  an  elevation  of  2,600  feet  in  Ceylon,  in  a  relatively  dry 
climate,  a  5rield  of  2  lb.  of  rubber  per  tree  has  been  obtained  during 
1905. 

Experimental  tapping  was  also  commenced  on  Glenburn 
estate  (T.A.,  May,  1909),  in  the  Nilgiris,  3,500  feet  above  sea- 
level  ;  745  trees  were  tapped  in  comparatively  dry  weather  and  in 
six  days  twenty-one  men  obtained  45  lb.  2  oz.  of  latex,  which 
yielded  15  lb.  11  oz.  of  dry  rubber. 

Ten  trees  planted  in  Cachar,  North-East  India  (Agr.  Jour. 
India,  July,  1907),  amongst  tea,  in  1897,  were  tapped  from 
December,  1906,  to  March,  1907,  and  yielded  10  lb.  of  rubber. 


CHAPTER    XVIII. 


YIELDS    IN  THE  DUTCH    EAST  INDIES,  BORNEO, 
AFRICA,    ETC. 

At  the  present  time  Malaya  and  Ceylon  are  the  principal 
producers  of  plantation  Para  rubber,  and  when  the  statistics 
regarding  yields  from  those  countries  have  been  dealt  with  this 
part  of  our  subject  is  almost  completed.  There  are,  nevertheless, 
enormous  areas  in  the  Indo-Malayan  region,  outside  the  countries 
already  dealt  with,  where  large  numbers  of  Hevea  plantations 
have  been  estabhshed,  the  more  notable  being  Sumatra,  Java, 
Borneo,  and  Africa.  It  is,  therefore,  desirable  to  deal  with  the 
records  of  crops  from  plantations  in  these  parts  of  the  tropical 
belt. 

Yields  in  Sumatra. 

Sumatra  is,  from  the  standpoint  of  acreage  under  Hevea, 
the  most  important  country  in  the  Dutch  East  Indies  Un- 
fortunately, the  number  of  old  or  bearing  trees  is  insignificant ; 
but  there  is  a  considerable  amount  of  information  available 
regarding  the  pelds  from  trees  of  a  known  age  which  may  prove 
useful  in  compiling  estimates  of  future  output  from  these  areas. 


Hevea  Trees. 

Yield  in  lb 

Name. 

Age. 

Number. 

Acres. 

Total. 

Per 

tree. 

Per 
acre 

Sumatra  Para     . 

3-4 

— 

— 

— 

— 

200 

United  Sumatra 

3-5 

1,850 

20 

1,600 

0-87 

80 

do. 

•       3-5 

6,000 

55 

4.300 

0-72 

78 

do. 

3-5 

1,200 

10  1 
85] 

5-7 

9,200 

17.300 

1-70 

182 

do. 

3-5 

12,000 

115  i 

•       5-7 

11,500 

no  \ 

50,500 

2-15 

224 

Sialang 

.        4-6 

12,000 

151 

16,767 

092 

III 

Anglo-Sumatra  . 

•        4-6 

3,676 

29 

3,282 

0-89 

113 

do 

4-7 

49.796 

432 

54.252 

I'og 

126 

Serdang  Central 

■       4-7 

12,500 

100 

6,830 

0'54 

68 

United  Serdang  . 

4-7 

74.094 

— 

67,828 

092 

— 

Serbadjadi 

•      4i-5 

13,000 

— 

4.504 

0-35 

— 

Sungei  Kari 

■        5-6 

18,211 

151 

16,767 

0-92 

Ill 

Deli  Moeda 

5-7 

9,000 

— 

17,600 

1-95 

— 

Bandar  Svunatra. 

5-7 

10,944 

— 

18,000 

1-73 

— 

United  Serdang  . 

•        5-7 

111,500 

976 

218,530 

1-95 

221 

Tapanoeli 

7 

25,006 

— 

12,500 

0-50 

— 

In  several  instances,  notably  Sialang  and  Serdang  Central, 
the  trees  were  only  tapped  for  6  or  8  months.  In  United  Serdang 
only  5638,  and  on  Tapanoeli  3,035  trees  were  in  the  tapping  round 
at  the  commencement  of  operations.  On  the  property  of  the 
United  Sumatra  the  Hevea  was  mixed  with  coffee,  which  was 


298  PARA     RUBBER. 

finally  removed.  On  Bandar  Sumatra  the  number  given  repre- 
sents the  average  tapped  throughout  the  year,  there  being  only 
6,300  trees  tapped  at  the  beginning  and  15,000  at  the  end  of  the 
year. 

The  yield  obtained  from  young  trees,  five  years  old,  in  Sumatra 
is  shown  in  the  returns  from  Glen  Bervie  Estate.  At  the  begiiining 
of  the  financial  year  1,200  trees  were  tapped,  6,337  in  the  n^iddle 
and  10,000  at  the  end  of  the  year.  The  yield  obtained  was  at 
the  rate  of  approximately  i  lb.  per  tree,  per  annum. 

The  above  yields  compare  very  favourably  with  those  from 
young  trees  in  Ceylon,  but  are  not  equal  to  the  yields  from  Malaya. 
The  main  reason  is  that  most  of  the  Hevea  trees  were  growing 
on  old  coffee  land. 

Yield  from  Old  Trees  in  Sumatra. 

Arbuthnot  does  not  regard  a  yield  of  2  lb.  per  tree  as  very 
satisfactory,  and  points  out  that  on  the. property  of  the  United 
Sumatra  company  there  are  several  old  trees  which  have  5nelded 
from  9  to  25  lb.  each.  Eighteen  trees,  10  years  old,  gave  9-2  lb. 
each  ;  when  11  years  old,  15  lb.  ;  at  12  years,  i8-8  lb. ;  at  13  years 
of  age,  25  lb.  each ;  thus  proving  that  the  yield  from  well-established 
trees  in  Sumatra  is  comparable  with  that  in  Malaya. 

On  the  properties  owned  by  the  Sumatra  Para  company 
there  are  many  old  trees.  It  was  stated  at  the  last  annual  meeting^ 
by  Mr.  Arbuthnot  that  the  trees  planted  in  1898-9  yielded  at  the 
rate  of  900  lb.  per  acre,  and  that  the  1902  planting  gave  700  lb.  per 
acre,  the  ages  of  the  trees  on  these  two  blocks  being  about  12 
and  9  years  respectively. 

Yields   from    Notable  Sumatra   Estates. 

There  are  several  estates  in  Sumatra,  notably  those  owned 
by  the  Sumatra  Para,  United  Sumatra,  and  other  companies, 
which  have  given  good  yields  in  the  past  few  years. 

The  Sumatra  Para  company  in  the  year  1907-8  tapped  about 
20,000  trees,  some  of  which  were  4  to  6  years  old,  and  the  remainder 
— 9,109 — 8  to  9  years  old,  the  yield  therefrom  being  at  the  rate  of 
3-13  lb.  per  tree,  per  annum.  In  the  following  year,  from  the  same 
trees,  together  with  an  additional  14,000  young  trees,  a  yield  of 
2-I7  lb.  per  tree  was  returned.  In  1909-10,  from  approximately 
9,000  trees  10  to  11  years  old,  and  28,000  trees  up  to  8  years 
old,  an  average  yield  of  3^  lb.  per  tree  was  obtained.  For  igio-ii, 
it  was  reported  that  over  the  whole  tapping  area  of  450  acres 
some  475  lb.  per  acre  was  got  from  trees  4  to  12  years  old. 

During  the  year  1910-11  the  United  Sumatra  Company 
obtained  about  2  lb.  per  tree  from  trees  up  to  9  years  old, 
with  some  17  older  trees. 

Yields  from  Hevea  in  Java. 

Though  the  acreage  under  Hevea  in  Java  is  now  large,  there 
are  very  few  estates  which  have  been  tapping  for  a  year  or  longer. 
The  Algemeene  Belgisch-Javische  CM.   report   that   5,000  trees- 


PARA     RUBBER 


299 


scattered  over  122^  acres,  only  4  years  old,  gave  a  yield  of  0-8  lb. 
each,  equivalent  to  33  lb.  per  acre.  The  Belgischo-Nederlandsche 
CM.  state  that  35,000  trees  over  420  acres,  when  3  to  5  years  old, 
gave  I -03  lb.  per  tree  or  86  lb.  per  acre.  The  Fransch-Neder- 
landsche  Koloniale  CM.  obtained  from  trees  4,  5,  and  6  years  old 
respectively  0-52,  0-92,  and  1-42  lb.  of  dry  rubber  per  tree,  per 
annum. 

At  Buitenzorg,  where  several  trees  are  growing  on  poor  soil, 
those  8  years  old  have  given  i  lb.  7  oz.  per  tree,  per  annum,  the 
tapping  having  been  done  every  alternate  day,  the  pricker  im- 
mediately following  the  parer  on  every  occasion. 

Yields  in   British  North  Borneo. 

As  in  Java,  there  are  few  estates  which  possess  large  trees 
in  bearing.  The  only  trees  which  appear  to  have  been  tapped  for 
a  considerable  period  are  those  on  Sekong  and  Sapong  estates 
and  at  the  experiment  station,  Tenom.  The  following  table  will 
serve  to  show  the  probable  yields  on  good  soil  in  Borneo  : — 

Hevea  Trees. 
Age.        Number.        Acres. 
4-5  26,947  — 

4-6  6,723  22 

5-6i  60  — 

4-10  22,367  74 

8  &  over        6,700  — 

10  11,317  — 

The  British  Borneo  Para  Rubber  Co.  inform  me  that  32,000 
trees,  averaging  5  years  in  age,  yielded  12,011  lb.  in  the  first  period 
of  tapping. 

Yields  in  the  Gold  Coast. 

Four  trees,  10  years  old,  were  tapped  for  the  first  time  in  1903, 
and  yielded  4  lb.  3  oz.  of  dry  rubber,  or  an  average  of  i  lb.  |  oz.  per 
tree.  Notwithstanding  the  quantity  of  rubber  extracted,  Johnson 
states  that  the  trees  show  no  signs  of  having  suffered  in  the  slightest 
degree. 

The  amount  of  rubber  yielded  by  Hevea  and  Funtitmia  trees 
(Johnson's  Report,  1905),  may  be  compared  by  consulting  the 
tables  given  below  : — 


Yield  in  lb. 

Total. 

Per  tree. 

Per  acre. 

22,990 

085 

— 

9.560 

1-42 

432 

107 

1-8 

— 

35.134 

1-57 

473 

10.395 

i'55 

— 

32,723 

298 

— 

Number  of 
Trees  tapped. 

Age  of  Trees, 
in  years. 

Date  of 
tapping. 

Average  yield  of 

Rubber  per  tree. 

lb.     oz. 

Hevea  brasiliensis    . .      4 
Funtumia  elastica    . .      i 

10 

7     .. 

1  Nov.  1903     . 

\  Dec.   1903    ■ 

Dec.   1901    . 

•  j            I       of 
0       4 

•  ■      I 

9     •• 

1903    • 

0       I 

•  ■      I 

9      .. 

1903    • 

0       4 

Regarding  the  yield  from  Hevea  brasiliensis,  Johnson  remarks 
that  it  must  not  be  taken  as  a  criterion  of  the  anticipated  yield 
from  trees  of  this  age  cultivated  in  West  Africa,  and  points  out  that 
the  trees  referred  to  are  growing  in  poor,  gravelly  soil  on  the  top  of 
a  hill  under  unfavourable  conditions. 


300  PARA     RUBBER 

Tudhope  states  that  in  1908,  at  Aburi,  14  trees,  with  an  average 
girth  of  about  igj  inches,  were  tapped  on  the  half-spiral  system, 

3  times  a  week  from  19th  November  to  31st  December,  1908.  A 
yield  of  2  lb.  8J  oz.  of  dry  rubber  was  obtained. 

The  Director  of  Agriculture,  in  his  annual  report  for  1909, 
states  that  thirty  trees,  5^  years  old,  and  with  an  average  girth 
of  24  inches,  were  selected  for  the  purpose  of  tapping,  and  a  yield 
of  5  lb.  14  oz.  of  dry  rubber  obtained  therefrom,  which  shows 
that  it  will  well  repay  planters  to  cultivate  this  species  of  rubber 
tree  in  that  colony.  Three  blocks  containing  15,  15  and  14  trees 
respectively  were  tapped  at  Aburi,  and  the  results,  2  lb.  5|  oz., 

4  lb.  5J  oz.,  and  4  lb.  5f  oz.,  are  very  encouraging.  The  third 
block  was  tapped  in  the  previous  year,  and  yielded  2  lb.  8|  oz, 
of  dry  rubber.  The  tapping  at  Tarquah  was  stopped  after  twelve 
cuts  had  been  made,  but  it  was  continued  at  Aburi,  and  the 
results  were  better  than  in  the  previous  year.     Tapping  on  Block 

I.  was  stopped  after  fourteen  incisions  had  been  made,  as  the  V 
knife  appeared  to  cause  considerable  damage  to  the  trees.     Blocks 

II.  and  III.  were  continued  until  the  22nd  December,  when  the 
Harmattan  set  in,  and  it  was  decided  to  stop  tapping  for  a  time. 
Twenty  cuts  had  been  made,  and  a  yield  of  4J  oz.  and  5  oz.  per 
tree  obtained. 

Yields  in  Cameroon,  Togo,  and  Nigeria. 

The  following  yields  (Tropenpflanzer,  Dec,  1910),  have  been 
recorded  from  three  lo-year-old  trees  in  the  Cameroon,  tapped 
daily ;  in  the  first  two  there  was  an  interval  of  six  months 
between  the  two  series  of  tappings  : — 

Tree.         Girth.  Method  of  No.  of         Total  Yield. 

Tapping.  Tappings.  ozs. 

1  .  .      3  ft.  5  ins.    .  .      Full  herring-bone  59  . .        20-98 

2  ..  do.  ..      Separate  oblique  cuts  ,.  56  ..        25"i6 

3  .  .      3  ft.  7  ins.     . .      Spiral  .  .  20  .  .  8-8o 


5494 
The  separate  oblique  cuts — 4  inches  long — were  made  in  rings 

around  the  stem,  and  each  day  a   new   ring  of  -^uts  was  made   2 

inches  below  the  previous  one. 

In  Togo  (Tropenpflanzer,  Dec,  1910),  a  tree  seven  years  old, 

with  a  girth  of  24  inches,  was  tapped  for  12  consecutive  days  in 

three  spirals  eight  inches  apart,  and  yielded  14^-  oz.  of  dry  rubber. 
In  Nigeria  (Ann.  Rep.,  For.  and  Agr.  Dep.,  1909),  100  trees, 

8  years  old,  were  tapped  and  yielded,  in  23  tappings,  61  oz.  per  tree  ; 

others  15  years  old  gave  i  lb.  4  oz.  in  26  tappings. 

Yields  in  the  Congo  Free  State. 

At  Mayumbe,  some  lo-year-old  Hevea  trees  each  gave  (Rub. 
Exh.  Handbook,  1911),  in  30  tappings,  296  grammes  (10^  oz.) 
of  dry  rubber  ;  others  gave  99  grammes  (3J  oz.)  in  10  tappings. 
Ten-year-old  trees  in  poor  soil  at  Boma,  where  there  is  a  well- 
defined    dry   season  of   from  5  to  6  months,  each  yielded  188-5 


PARA     RUBBER  301 

grammes  (6^  oz.)  in  28  tapping  days.  Trees  of  the  same  age  at 
Coquilhatville,  in  40  tapping  days,  yielded  1,499  grammes  (3  lb. 
5  oz.).  At  Tlambi,  ii-year-old  trees,  tapped  11  times,  gave  an 
average  per  tree  of  140  grammes  (5  oz.).  On  another  occasion, 
tapped  10  times  on  alternate  days,  they  averaged  227  grammes 
(8  oz.)  per  tree. 

Yields  in  Burmah,  Indo  China,  New  Guinea,  and  Queensland. 

According  to  Snow  (I.R.W.,  Jan.,  1911)  several  trees  in 
Lower  Burmah,  when  five  years  old,  measured  27  inches  in  girth 
at  a  yard  from  the  ground,  and  yielded  |  lb.  of  rubber  each. 

The  New  Guinea  Company  report  (Gummi-Zeitung,  Feb.  3rd, 
191 1)  that  several  eight -year-old  trees,  measuring  60  cm.  (24 
inches)  at  one  metre  from  the  ground,  produced  279  grammes  (g'S. 
ozs  )  of  rubber  in  one  month. 

Several  records  of  yields  in  Cochin  China  are  available.  One 
record  (J.  d'  Agr.  Trop.,  July,  1907)  states  that  seven  9-year-old 
trees  at  Suoi  Giao,  from  one  tapping,  gave  i|  oz.  of  rubber.  The 
same  authority  states  that  the  average  quantity  of  latex  obtained 
from  each  of  the  7  and  9-year-old  trees,  when  tapped  145  times, 
was  respectively  2,256  and  3,331  c.c.  The  mean  amount  of 
caoutchouc  in  the  latex  being  31-3  p§r  cent.,  the  yields  of  rubber 
were  1-55  lb.  for  the  7-year  trees,  and  2-30  lb.  for  those  9  years  old. 
Ten  trees  planted  in  1898  (Str.  Bull.,  Jan.,  1910),  gave,  in 
1909,  when  tapped  every  day,  the  equivalent  of  about  2^-  lb.  dry 
rubber. 

At  the  Kamerunga  Station,  Queensland,  ten  trees  about  8 
years  old,  with  average  girth  21-3  inches,  were  tapped  irregularly, 
some  nearly  every  day,  others  almost  alternate  days,  an  average 
of  41-5  times  between  19th  February  and  23rd  May,  1907.  Various 
methods,  including  the  full  spiral,  were  used.  The  average  yield 
per  tree  per  tapping  was  0-315  oz.,  which  at  180  tapping  days, 
equals  3  lb.  8f  oz.  per  year  per  tree. 

Yields  in  Surinam. 

There  are  several  old  Hevea  trees  in  Surinam  which  have  been 
somewhat  experimentally  tapped  and  have  given  encouraging 
yields.  In  1908  (Rep.  Dep.  Agr.)  ten  trees  planted  at  Waterland  in 
1897,  and  therefore  about  11  years  old,  gave  an  average  of  2-4  lb. 
each,  consisting  of  i-8  lbs.  of  first  grade  and  o-6  lbs.  of  scrap. 
A  year  later  a  yield  of  3  lb.  per  tree  was  reported  from  300 
ten-year-old  trees  in  the  same  district. 


CHAPTER  XIX. 

GENERAL    CONSIDERATIONS     AFFECTING    YIELDS. 

When  dealing  with  the  question  of  yields  of  dry  rubber  from  a 
known  acreage  or  number  of  trees,  it  is  necessary  to  indicate 
the  method  of  tapping  adopted,  the  age  of  the  trees,  and  the 
quality  of  the  resultant  rubber.  The  age  and  size  of  trees  greatly 
influence  the  quantity  and  quality  of  the  rubber,  and  it  is  to  be 
regretted  that  more  yields  over  large  acreages  for  several  years  in 
succession  are  not  at  hand.  Nevertheless,  we  do  possess 
information  of  the  yield  from  particular  trees  during  certain  years 
and  from  large  acreages  of  known  age  for  a  limited  period  ;  from 
these  a  fairly  reliable  statement  of  probable  yields  can  be  arrived 
at.  It  should  be  clearly  understood  that  the  yield  from  trees  of 
the  same  age  may  be  douBled,  trebled,  or  quadrupled  within  a 
year  by  a  change  in  the  method  of  tapping,  and  that  those  methods 
usually  give  the  largest  yields  which  tap  the  latex  tubes  over  the 
largest  area. 

Natural  Variations. 

It  should  also  be  remembered  that  individual  trees,  either  from 
internal  or  external  causes,  show  considerable  variation  in  the 
quantity  and  quahty  of  latex  they  give,  though  of  the  same  age  and 
tapped  in  a  similar  manner.  At  Henaratgoda,  where  the  trees 
range  in  age  from  15  to  30  years,  and  where  tapping  has  been 
done  on  various  sections  of  the  trees  from  the  base  to  6,  16,  20,  30, 
and  50  feet,  the  opportunities  to  observe  the  variation  in  yield  of 
latex  and  rubber  have  been  numerous.  The  first  six  feet  from  the 
base,  though  tapped  over  the  same  area,  in  the  same  manner,  and 
with  the  same  implements,  gave  from  ;/-,  oz.  to  nearly  two  ounces 
of  rubber  per  tapping  per  tree.  Other  parts  of  the  stems  of 
individual  trees  have  varied  in  their  daily  yield  of  rubber  from 
'i  oz.,  5.!  oz.,  and  A  oz.,  to  Ji!  oz.  In  one  case,  where  the 
tree  has  been  regularly  tapped  from  the  base  to  a  height  of 
50  feet,  the  yield  ot  dry  rubber  has  sometimes  been  as  high  as  8|oz. 
per  tree  per  tapping,  and  on  other  occasions  as  low  as  J  oz.  Such 
variations  can,  in  most  cases,  be  mainly  attributed  to  internal 
conditions  rather  than  external  chmatic  forces. 

Variation  in  jaeld  from  individual  trees  has  also  been  reported 
by  Pearson  (I.E. World)  in  the  Amazon,  some  trees  there  bleeding 
freely  and  others  reluctantly.  Several  trees  furnish  thick  creamy 
latex,  others  yield  thin  watery  latex  and  several  gave  no  latex  at 
all 


PARA     RUBBER  303 

Estate  Conditions  Affecting   Yields. 

It  is  apparent  from  the  foregoing  chapters  upon  yields  of 
rubber  from  Hevea  trees  in  various  countries,  that  considerable 
variation  must  be  allowed  for.  The  external  factors  which  are 
responsible  for  this  variation  are  numerous.  Some — distance 
in  planting,  frequency  of  tapping — have  already  been  recognised  ; 
others — such  as  humidity  and  atmospheric  pressure — are  still 
obscure.  It  is  therefore  necessary  to  consider  the  more  important 
estate  conditions  which  appear  to  have  an  effect  on  yield. 

Yields  in  Different  Countries. 

The  most  striking  differences  in  yield  are  seen  between  the 
two  leading  countries — Ceylon  and  Malaya.  Elsewhere  it  has 
been  shown  that,  whereas  the  yields  in  Ceylon  from  trees  six  to 
seven  years  old  may  range  from  075  to  1-59  lb.  per  tree  per  annum, 
those  in  Malaya  range  from  i-6o  to  2-47  lb.  per  tree  per  annum 
from  trees  of  approximately  similar  ages.  Tapping  in  Ceylon 
cannot  usually  be  commenced  before  the  middle  of  the  fifth  year; 
in  Malaya  many  trees  have  yielded  from  one  to  two  pounds  of 
rubber  each  before  attaining  that  age.  This  variability  in  yielding 
capacity  renders  estimates,  experiments,  and  observations  in 
Ceylon  of  little  value  for  Malaya.  The  soils,  climate,  and  methods 
of  cultivation  in  Ceylon  are  unlike  those  in  Malaya  ;  and  as  on 
these  depend  the  growth  and  ultimate  yields  of  rubber,  the  sooner 
the  differences  are  acknowledged  by  Ceylon  enthusiasts  the  better. 
Manuring  in  Ceylon  will  undoubtedly  compensate  for  many  of  the 
drawbacks  in  that  country.  This,  combined  with  cheap  produc- 
tion, wiU  enable  planters  in  Ceylon  to  successfully  compete  with 
their  fellows  in  most  parts  of  the  tropics. 

Rate  of  Growth  and  Ultimate  Yields. 

It  seems  almost  incredible  that  Hevea  trees  may  take  from 
three  to  seven,  and  even  nine,  years  to  reach  the  producing 
stage.  This  variation  in  bearing  age  is  very  large,  but  covers  a 
multitude  of  conditions  under  which  plants  are  at  present  culti- 
vated. Trees  in  bearing  at  three  years  are  frequently  to  be  seen 
in  Province  Wellesley,  Selangor,  and  Serdang  ;  others  in  Uva, 
Ceylon,  at  least  2,500  feet,  and  in  Southern  India  at  about  3,000 
feet  above  sea-level,  may  take  the  longer  period.  In  many  circles 
it  is  accepted  that  a  fair  proportion  of  the  trees  grown  alone  on  a 
clearing  can  be  tapped  when  four  years  old  in  favoured  parts  of 
Malaya,  at  five  years  in  other  parts  of  Malaya  and  Sumatra, 
and  at  six  years  in  most  Ceylon  districts  ;  where  the  trees  are 
planted  among  old  tea,  coffee,  or  cacao,  eight  years  is  often  re- 
quired before  successful  tapping  operations  can  be  carried  out. 
If  a  difference  of  two  years,  or  even  one  year,  is  ultimately  to  be 
associated  with  Hevea  trees  in  the  areas  enumerated,  it  is  a  matter 
of  the  utmost  importance  to  all.  This  difference  is  not  merely 
one  of  the  age  at  which  trees  can  be  tapped  for  the  first 
time  ;  it  indicates  the  probability  of  a  much  reduced  total  5deld 
from  trees  requiring  the  maximum  period  for  attainment  of 
maturity.     Where  the  trees  take  six  years  to  reach  the  tappable 


304  PARA     RUBBER 

stage  there  must,  on  account  of  inferior  soil,  unfavourable  climatic 
or  other  conditions,  be  a  much  slower  average  rate  of  grovvth 
during  what  may  be  termed  the  first  cycle  ;  as  the  slow-growing 
trees  get  older  they  will  not  have  a  better  chance  of  increasirig 
their  rate  of  growth  above  those  characterised  by  more  rapid 
development,  and  the  secondary  and  subsequently  renewed  barks 
will  probably  require  a  similarly  longer  period  to  mature.  In 
other  words,  there  will  be  less  renewed  bark  available  on  the  slow- 
growing  trees  after  a  given  period.  And  the  bark  is  the  mother 
of  rubber.  It  may  be  argued  that  quantity,  and  especially 
thickness,  of  bark  is  not  the  only  criterion  of  total  yield  ;  it  is 
granted  that  in  some  circumstances  thin-barked  trees  yield  as 
much  per  area  of  bark  excised  as  others  with  thicker  bark,  es- 
pecially when  the  former  trees  are  older.  But,  taking  trees  of  the 
same  age,  there  seems  every  reason  to  expect  that  those  with  more 
rapid  rates  of  growth  and  thicker  bark  tissues  will  be  capable 
of  5rielding  larger  quantities  of  rubber  in  the  future. 

In  some  instances  the  trees  have  not  reached  the  productive 
stage  at  an  early  age  on  account  of  bad  methods  of  cultivation  ; 
in  such  cases  the  subsequent  growth  may  be  quite  equal  to  that  on 
the  better-class  estates. 

Effect  of  Intercrops  on  Yields. 

The  effect  of  most  intercrops  on  yields  is  similar  to  that 
of  weeds  or  of  poor  soil..  The  growth  of  the  Hevea  tree  is  con- 
siderably slower,  and  the  ultimate  yield  of  rubber  is  therefore 
less.  Hevea  intercropped  with  tapioca  and  cultivated  in  the 
native  fashion  is  often  two  years  behind  in  growth.  This  should 
be  allowed  for  in  estimating  rubber  crops. 

Crops  such  as  Indian  corn,  tapioca,  sugar,  pineapples,  are 
known  to  have  a  very  exhausting  effect  ;  others,  such  as  coffee 
and  cacao,  are  less  detrimental,  especially  when  properly  dis- 
tanced ;  finally,  there  are  a  few,  of  the  indigo  and  banana  types, 
that  are  reputed  to  improve  the  fertility  of  the  land.  The  effect 
of  intercrops  on  the  available  food  supplies  in  the  soil  is,  however, 
generally  admitted.  They  undoubtedly  absorb  food  which  might 
otherwise  have  been  used  by  the  growing  rubber  trees. 

In  many  cases  they  preserve  the  soil  moisture,  a  consideration 
of  some  importance  in  dry  districts  of  Ceylon,  India,  and  Java, 
but  negligible  in  many  parts  of  Malaya,  where  the  water-level  is 
very  near  to  the  surface  all  the  year  round.  Intercrops  also 
shade  the  trunks  of  the  Hevea  trees  and  thus  check  whatever 
influence  sunlight  may  have  on  the  trees  or  the  latex.  This  effect 
is  Hmited,  with  low-lying  crops  such  as  coffee  and  tea,  mainly  to 
the  early  morning  and  to  the  evening,  though  with  cacao  it  is  in 
force  the  greater  part  of  the  day.  Man\-  of  the  intercrops  often 
interfere  with  direct  supervision  during  tapping,  though  this 
can  be  remedied  by  proper  spacing  of  both  classes  of  plants. 

It  is  obvious  that,  despite  the  unfavourable  effect  that 
intercrops  have  upon  the  growth  of  the  Hevea  trees  and  upon 
the  ultimate  yields,  they  may,  by  necessitating  a  much  wider 
distance   for   the    Hevea,   be    instrumental   in    effecting   a   great 


PARA     RUBBER  305 

improvement  in  later  years.  Many  estates  plant  the  Hevea  trees, 
if  without  intercrop,  from  15  to  20  feet  apart.  If  intercrops  are 
used,  the  distance  between  the  Hevea  trees  is  increased  to  20 
or  25  feet,  a  difference  which  ensures  much  larger  and  better 
developed  rubber  trees  in  the  future. 

In  a  general  way  it  may  be  stated  that  the  lowest  yields 
have  hitherto  been  obtained  in  countries  or  upon  estates  where 
intercrops  were  regularly  cultivated.  The  maximum  crops  have 
been  obtained  in  Malaya  and  Sumatra,  where  Hevea  has  been 
grown  as  a  single  product.  Whether  or  not  this  is  due  to  mis- 
management of  the  intercrops  remains  to  be  proved  ;  meanwhile, 
the  tendency  in  Malaya  and  Sumatra  is  to  remove  them  from 
estates  upon  which  they  have  been  planted.  On  the  other  hand, 
mainly  owing  to  the  high  prices  ruling  for  sugar,  coffee,  and  other 
catch-crop  products,  many  planters  prefer  to  cultivate  such  crops 
among  the  rubber  in  the  belief  that  the  total  net  profit  over  a 
number  of  years  from  rubber  and  other  products  will  be  greater 
than  from  rubber  alone. 

Yield  and  Distance  in  Planting. 

For  several  years  planters  have  not  been  able  to  decide  the 
question  of  the  best  distance  in  planting,  niany  believing  that  the 
closely-planted  trees  would  yield  more  per  acre  than  those  widely 
planted.  During  1906  some  very  good  results  were  obtained  on 
estates  where  trees  were  widely  planted ;  on  closely-planted 
properties  much  difficulty  was  experienced  in  thinning-out  the 
undesirable  trees. 

Yields  on   Vallambrosa  Estate. 

The  following  statement  of  approximate  yields  from  the 
older  fields  belonging  to  the  Vallambrosa  Rubber  Company  was 
compiled  from  the  manager's  report  and  presented  by  the  Direc- 
tors in  their  Annual  Report  for  1906-07  : — 


03 

0) 

■a 

C.-C 

^l 

ll 

11 

0  & 

0^ 

u 

■a 
■3 

"3 
3 

0 

a. 
1 

Remarks. 

Q  ^ 

a 

25 

'^ 

f> 

iz; 

> 

Feet. 

lb. 

lb. 

lb. 

24  X  12 

4.642 

3 

2j 

12,765 

77 

212J 

Planted  1899  (about 
150  trees  per  acre). 

10  X  10 

)    8,000 
/  28,301 

l\ 

I* 

54.451 

242 

363 

This  field  was  planted 
through  coffee  in  1898, 
and  thinned  -  out  to 
260  270  trees  per 
acre. 

12  X  10 

6,225 

2 

I 

6.225 

155 

155 

Planted  1900.  Thinned 
to  250  trees  per  acre. 

'  10,000 

l\ 

I 

70,820  1 

)  60,820 

/ 

12  X  10  ! 

1 

oz. 

147 

ii7i 

Planted  from  1899  to 

'  29,113 

I 

5 

9.097  ) 

1901.  Thinned  to  250- 
270  trees  per  acre. 

60 
^50 

40 

680 

930  147.1°'  153.358 


3o6  PARA     RUBBER 

Caledonia  Estate. 
Some  trees  were  planted  on  Caledonia  estate  many  years 
ago,  more,  it  is  said,  with  the  idea  of  filling  in  an  unsightly  swampy 
piece  of  ground  than  with  an  eye  to  profit.  For  several  years  this 
block,  of  a  few  acres  in  extent  (planted  lo  by  lo),  was  pointed  out 
as  an  awful  example  of  the  effects  of  close  planting.  The  trees 
were  tall,  weedy  in  appearance,  and  of  small  girth.  Moreover, 
they  were  subjected  to  all  kinds  of  experiments  in  the  way  of 
pruning,  lopping,  and  tapping,  and  the  soil,  according  to  experts, 
was  by  no  means  specially  suitable  for  rubber.  That  block  of 
trees,  however,  yielded  at  the  rate  of  900  lb.  per  acre  in  one  year  ; 
previously  it  had  given  378  lb.  per  acre  in  twelve  months. 

Yields  on  Highlands  and  Lowlands  Estate. 

The  Annual  Report  of  the  above  Company  for  1906  gives 
some  interesting  information  in  favour  of  widely-planted  trees. 
The  report  made  by  Mr.  R.  W.  Harrison  states  that  there  is  one 
block  of  trees,  16  acres  in  extent,  containing  807  trees  planted  30 
by  25  feet.  These  trees,  nine  years  old,  were  tapped  three  times 
during  1906  and  gave  2,500  lb.  at  the  first,  1,469  lb.  at  the  second, 
and  1,773  lb.  at  the  third  tapping,  or  a  total  of  5,742  lb.  fron  807 
trees,  equivalent  to  a  yield  of  over  7  lb.  per  tree.  These  may  be 
exceptional  results,  but  they  certainly  indicate  that  satisfactory 
returns  can  be  obtained  when  the  trees  are  not  closely  planted. 

As  pointed  out  by  Etlierington,  the  distance  of  -;o  1  y  25  ft. 
allows  2,250  cubic  feet  of  soil  to  each  tree  and  an  average  spread 
of  foliage  of  750  square  feet  ;  under  these  conditions  the  food- 
producing  and  absorbing  power  of  each  tree  must  be  considerable. 

Permanent  close  planting  has,  after  seven  or  eight  years,  an 
effect  similar  to  that  of  impoverished  soils.  The  trees  do  not 
make  the  same  growth,  the  bark  takes  longer  to  renew,  and  the 
yield  does  not  increase  as  it  does  on  widely-planted  or  thinned-out 
properties.  Future  yield  is  therefore  to  be  correlated  with  the 
rate  of  the  trees'  growth. 

Yield  and  Size  of  Tree. 

Ridley  and  Derry  in  their  Annual  Report  for  1904  published 
some  figures  showing  ratio  of  yield  to  the  size  of  the  tree. 
The  following  table  was  given  : — 

Comparative  yield  per 
Girth  at  3  feet  from  ground.  inch  of  girth  at  3  feet 

from  ground. 
Under  2  ft.  girth  Under    J  oz. 


From  ^  ft.  to  2  ft.  6  in. 

From  2  ft.  6  in.  to  3  ft. 

From  3  ft.  to  3  ft.  6  in. 

From  3  ft.  6  in.  and  over 


J  oz. 
Under    \  oz. 

\  oz. 
Over      i  oz 


Ridley  and  Derry  believe  that  the  best  growing  period  is 
between  the  6th  and  15th  years,  during  which  time  trees  may 
increase  from  about  24  inches  in  girth  to  60  inches  or  more,  thus 
showing  an  annual  increment  of  from  3  to  6  inches.     Thev  claim 


PARA     RUBBER  307 

to  have  shown  that  trees  closely  planted  do  not  make  a  satis- 
factory increment  of  growth,  and  that  the  yield  of  rubber  increases 
with  the  size  of  the  tree  from  under  J  oz.  of  dry  rubber  to  the  inch 
of  girth  for  small  trees  to  over  I  oz.  for  large  ones  ;  to  further 
emphasize  the  error  of  close  planting  they  have  submitted  the 
following  statements  taken  from  the  figures  of  their  experiments  : — 


No.  of  trees 

Average  girth 

Aggregate 

Dry 

tapped. 

per  tree. 

girth. 

Rubber. 

Remarks. 

ft.  in. 

ft.  in. 

lb.  oz. 

40 

2     3 

90     7i 

18     7i    1. 

Tapped 

20 

4     2 

83      7: 

25     6       1 

18  times. 

50 

I     9 

88     7  ■ 

18     Si 

15 

5     8 

85     7 

33     8 

Yield  and  Water  in  Soils. 

The  yields  of  rubber  which  are  now  being  chronicled  throw 
considerable  light  on  a  problem  which  has  engaged  the  attention 
of  cultivators  for  many  years.  It  was  originally  supposed  that 
Hevea  trees  throve  best  on  the  banks  of  rivers  where,  in  addition 
to  a  good  supply  of  available  plant  food,  there  was  always  abund- 
ance of  water  and  an  occasional  flooding  of  the  land.  As  pre- 
viously pointed  out,  it  was  in  consequence  of  this  that  botanical 
authorities  in  the  East  recommended  planters  to  select  similar 
areas  for  their  new  clearings  in  the  belief  that  to  imitate  Nature 
would  be  the  safest  and  probably  the  most  remunerative  plan. 
When  it  was  subsequently  reported  that  Hevea  trees  flourished  not 
only  along  the  river  banks,  but  on  the  low  hills  of  the  interior  of 
Brazil,  doubt  was  expressed  as  to  the  wisdom  of  planting  on  areas 
subject  to  periodical  inundation. 

As  a  result,  we  have  in  the  Indo-Malayan  region  Hevea 
rubber  trees  planted  on  all  classes  Of  soil,  some  very  dry  and  others 
exceedingly  damp.  It  is  well  known  that  the  majority  of  the 
Perak  and  Selangor  estates  now  in  bearing  are  on  land  where  the 
water-level  is  only  one  or  two  feet  from  the  surface.  In  Ceylon, 
Sumatra  and  Java,  the  majority  of  rubber  estates  are  not  so 
abundantly  supplied  with  water.  The  one  fact  which  vividly 
impresses  tourists  in  the  East  is  the  nearness  of  the  water-level 
to  the  surface  on  many  Malay  estates.  Now,  everyone  recognises 
that  the  highest  3aelds  have  been  obtained  from  these  estates, 
though  the  lateral  roots  are  more  or  less  immersed  in  water,  the 
taproots  have  disappeared  and  the  trees  are  growing  under  what 
would  normally  be  regarded  as  unnatural,  if  not  unhealthy,  con- 
ditions. The  water  factor  appears  to  be  of  more  importance 
during  the  first  eight  years  of  growth  than  most  experts  imagine. 

Atmospheric  Pressure  and  Yields. 

The  effect  upon  yields  of  variation  in  the  pressure  of  the  air 
is  as  yet  unknown.  The  behaviour  of  the  tree  at  high  altitudes 
cannot  serve  as  a  guide  upon  the  question,  for  there  many  other 
factors  come  into  consideration.  The  atmosphere  must  exercise 
its  pressure  upon  the  latex  in  two  opposing  directions  :    against 


3o8  PARA     RUBBER 

the  stream  flowing  out  of  the  cut  ends  of  the  latex  vessels,  and 
upon  the  trunk  of  the  trees.  This  latter  force  must  help  the  latex 
out  of  the  vessels,  with  the  aid  of  the  force  exercised  by  the  tissue 
tension.  At  first  glance  it  would  appear  very  much  the  greater, 
for  it  is  applied  to  a  larger  surface,  over  the  trunk,  while  the  other 
is  applied  to  only  the  small  cut  ends  of  the  latex  vessels.  But 
the  resistance  of  the  partly  unyielding  bark  to  the  pressure  of  the 
air  must  render  the  difference  in  intensity  of  the  force  less  in 
amount.  One  would  welcome  observations  upon  this  factor  of 
atmospheric  pressure.  The  variations  from  day  to  day  in  the 
yields  of  trees  are  sometimes  marked,  and  as  it  does  not  seem 
possible  to  refer  them  always  to  changes  in  moisture  conditions 
it  would  be  worth  while  to  determine  this  point.  It  must,  of 
course,  be  admitted  that  the  information  will  not  be  of  an  im- 
mediate practical  value,  since  atmospheric  pressure  is  beyond  our 
control,  but  it  may  throw  light  upon  estate  operations  wherein 
pressure  is  or  can  be  brought  into  force. 

Yield  and  Length  of  Time  Latex  Flows. 

The  length  of  time  that  latex  flows  from  a  freshly-made  cut 
has  a  direct  connection  with  the  yields  on  estates.  It  is  un- 
fortunate that  the  latex  flows  only  for  minutes,  instead  of  hours. 
The  length  of  time  that  latex  flows  is  dependent  upon  many  factors, 
some— the  anatomy  of  the  plant,  the  tissue  tension,  and  atmospheric 
pressure — are  beyond  our  control,  whilst  others,  such  as  the 
water  content  of  the  latex,  can  be  modified  during  collecting 
operations.  The  time  is  shortened  by  the  dryness  of  the  air,  by 
heat  and  by  sunlight.  The  former,  along  with  thickness  of  the 
latex,  often  necessitates  the  stopping  of  tapping  operations  in  dry 
seasons,  but  can  be  partially  controlled  by  the  use  of  water  from 
drip-tins  to  retard  the  coagulation  of  latex  at  the  cut  ends  of  the 
latex  tubes.  The  bad  effects  of  heat  and  sunlight  can  to  some 
extent  be  minimised  by  choosing  certain  times  of  the  day  for  tapping 
and  by  combining  this  with  compass  tapping  ;  some  intercrops^, 
especially  cacao,  shade  the  trunks  of  the  trees  throughout  the  day. 
Atmospheric  humidity  depends  almost  entirely  upon  the  location 
of  the  estate,  but  something  might  be  done  to  influence  this  in 
normally  dry  districts  by  the  retention  of  a  definite  proportion  of 
the  original  forest  to  serve  as  a  wind  break,  or  by  planting  wind- 
belts  or  bushy  intercrops  that  will  have  a  similar  effect.  By  thus 
impeding  the  circulation  of  air,  there  will  be  a  partial  retention  of 
moisture  that  has  come  from  the  soil  and  from  the  leaves. 

In  some  reports  of  tapping  on  the  Amazon  and  in  the  West 
Indies,  reference  is  made  to  the  renewal  of  the  flow  by  picking  ofi 
the  scrap  before  it  has  become  too  thick  ;  a  second  and  even  a  third 
flow  can  sometimes  be  obtained  by  this  means.  Hart  reported  this 
in  some  of  his  Trinidad  experiments,  and  Vernet  also  appears  to  have 
"refreshed"  the  cuts  twice  on  a  certain  day,  with  a  gradually 
decreasing  37ield,  though  it  is  doubtful  as  to  what  extent  the  knife 
was  used  by  him.     In  these  experiments  time  enters  as  a  factor,  the 


PARA     RUBBER  309 

interval  being  sufficiently  long  to  permit  of  an  accumulation  of 
latex,  of  varying  richness  in  caoutchouc,  towards  the  cut  ends  of 
the  latex  tubes. 

This  subject  is  not  so  trivial  as  it  may  on  first  consideration 
appear.  The  larger  the  quantity  of  latex  obtained  per  incision,  the 
greater  is  the  bark  economy  effected.  So  far  the  only  feasible 
operation  appears  to  be  to  maintain  open  latex  tubes  by  the 
passage  of  water  alone,  or  water  containing  ammonia,  along  the 
tapped  surfaces  as  soon  as  the  flow  begins  to  lessen. 

Yield  and  Superposition  of  Incisions. 

Vernet  (Journ.  d'Agric.  Tropicale,  April,  1910)  experimented 
to  find  out  what  was  the  effect  of  superposition  of  incisions  upon 
the  yield.  It  is  to  be  expected  that  an  upper  incision  will  to  some 
extent  prevent  the  downwardly-flowing  sap  from  reaching  and 
providing  with  nutriment  the  area  around  a  lower  incision.  And 
if  the  two  incisions  are  near  enough,  though  at  what  distance  we 
cannot  yet  say,  they  must  drain  not  only  the  same  systems  of 
laticiferous  vessels,  but  also  the  same  reserves  of  nutriment.  Vernet 
made  a  single  V  incision  upon  one  side  of  ten  seven-year-old  trees. 
Upon  the  other  side  he  made  two  V  incisions,  so  that  one  was  as 
much  higher  than  the  V  on  the  other  side  as  the  other  was  lower. 
The  incisions  were  renewed  six  times  : — 

70  double  incisions  gave  909  c.c.  of  latex. 
70  single  incisions  gave  620  c.c.  of  latex. 

Had  each  of  the  double  incisions  yielded  at  the  same  rate  as  the 
single  incision  there  would  have  been  1,240  c.c.  of  latex.  These 
results,  of  course,  do  not  throw  any  light  upon  the  second  of  the 
above  questions,  seeing  that  Vernet  does  not  tell  us  the  distance 
between  the  double  incisions.  Indeed,  he  does  not  mention  this 
point,  but  it  is  probable  that  he  made  the  cuts  far  enough  apart 
to  prevent  one  influencing  the  other  as  far  as  proximity  was  con- 
cerned. 

Factors  in  Yields  from  Individual  Estates. 

There  are  numerous  factors  which  have  an  important  relation- 
ship not  only  to  the  composition  of  an  estate's  crop,  but  to  the 
total  yield  from  a  particular  property.  Regularity  in  tapping, 
systems  of  coagulating,  washing,  and  other  operations  on  the  estate 
have  their  effect  on  the  total  yield.  Among  one  of  the  factors  is  that 
of  thickness  of  bark  shavings  and  cleanliness  in  picking  scrap. 

Rubber  from  Bark  Shavings. 

A  few  years  ago,  when  bark  parings  were  frequently  j\,  of 
an  inch  in  thickness,  and  the  picking  of  coagulated  scrap  from  the 
tapping  lines  was  not  carefully  attended  to,  a  considerable  yield 
of  rubber  was  obtained  from  shavings.  It  is  customary  to  collect 
all  shavings  and  accumulate  them  in  tanks  containing  water  with 
or  without  chemicals.  These  shavings,  when  thoroughly  steeped, 
are  washed  in  a  macerating  machine  and  the  rubber  extracted 
therefrom  shipped  as  washed  scrap.     In  the  early  tapping  days. 


310  PARA     RUBBER 

it  was  estimated  that  the  shavings  from  lOO  coolies'  work  would 
give  about  25  lb.  of  washed  rubber.  A  yield  of  7  per  cent,  of 
washed  scrap  rubber  from  bark  shavings  was  by  no  means  uncom- 
mon in  Ceylon  and  Malaya.  The  actual  quantity  of  rubber  in  the- 
thin  shavings  now  cut  away  is  very  small ;  much  more  is  attached 
to  the  strips  of  bark.  A  high  yield  from  bark  shavings  generally 
denotes  lack  of  supervision  during  paring  and  picking  operations. 
Earth  rubber  collected  from  the  ground  is  usually  very  impure 
and  does  not  always  figure  in  the  classified  rubber  from  estates ; 
on  some  large  properties  it  amounts  to  a  considerable  figure  in  the 
course  of  a  year. 

Percentage    of    Scrap   in    Total    Crop. 

The  percentage  of  scrap  in  the  total  dry  crop  varies  on  different 
estates,  even  where  the  same  system  of  grading  is  in  vogue.  First 
quality  crepe  or  sheet  should  be  from  70  to  80  per  cent,  of  the 
total  ;    in  dry  districts  60  per  cent,  is  sometimes  considered  fair. 

A  Ceylon  planter  (T.A.,  December,  1908),  after  making 
enquiries,  estimated  a  range  of  from  5  to  40  per  cent,  scrap. 
Where  it  is  said  that  no  scrap  is  obtained,  the  explanation  pro- 
bably lies  in  the  conversion  of  all  such  rubber  into  dark  crepe,  but 
even  then  the  product  should  be,  and  is  usually,  marketed  as 
crepe-scrap. 

At  a  recent  meeting  of  the  Malay  Planters'  Association,  it 
was  concluded  that  70  per  cent,  first  quality  was  a  fair  average. 
Mr.  Burn  Murdoch  gave  75  per  cent,  of  No.  i  as  the  result  of  his 
observations.  Mr.  Baxendale  thought  60  per  cent,  represented 
the  average  of  the  low  country  in  a  dry  season.  In  the  further 
course  of  the  discussion,  Mr.  H.  T.  Eraser  read  the  following  figures 
relating  to  a  series  of  experiments  lasting  over  six  months  : — 

First  three  months.     After  six  months. 

■  %  % 

No.  1         . .           .  .                85  83 

Lump        ....                   I  3 

Scrap        ....                 10  10 

Shavings               . .                  4  4 

Some  figures  are  given  by  Cramer  of  the  composition  of  the 
crop  upon  a  Malayan  estate  : — 

Old  Trees.  Young  trees. 

0/  0/ 

/o  /o 

No.  I                        .  .           74-64  74-77 

Lump                   . .            8-52  5-83 

Scrap                    ..          10-58  ii'73 

Shavings               ..            6-26  7-67 

Rather  high  proportions  of  lump  and  bark  rubber  are  shown. 

The  Klanang  Produce  Company  reported  that  their  crop  for 
1910  consisted  of  33,882  lb.  of  sheet,  29,931  lb.  of  number  one, 
and  29,852  lb.  of  number  two  crepe.  Other  five  Malayan  estates 
with  which  I  am  acquainted  show  the  percentage  of  scrap  rubber 
in  the  total  crop  to  be  18,  20,  22,  34,  and  55  per  cent.  ;  the  last 
was  from  an  estate  possessing  a  large  number  of  young  trees. 

In  the  annual  report  of  the  Golden  Hope  Rubber  Estates, 
Ltd.,  the  crop,  consisting  of  about  51,420  lb.,  was  divided  into  : 


PARA     RUBBER 


311 


number  i  fine  crepe  75  per  cent.,  number  2  fine  crepe  10  per  cent., 
number  3  scrap  10  per  cent.,  and  bark-scrap  5  per  cent. 

The  proportions  of  grades  in  the  1910-11  crops  of  the  Brieh 
Rubber  Estate  were  24,939  lb.  of  No.  i  sheet  and  crepe,  and 
8,974  lb.  of  No.  3  bark-scrap. 

Crop  Periodicity  in  Ceylon. 
One  is  accustomed  to  the  seasonal  crops  from  the  Amazon 
and  is  apt  to  imagine  that  on  the  contrary  the  plantation  in- 
dustry will  show  a  constant  increase  in  output  month  by  month 
and  year  by  year.  This,  however,  is  not  really  the  case,  as  there 
are  certain  factors  operating  in  most  of  the  rubber-growing  areas 
in  the  Middle-East  which  prevent  tapping  operations  from  being 
carried  out  with  that  regularity  characteristic  of  the  rest  of  the 
year.  While  it  is  true  that  the  majority  of  mature  Hevea  trees 
yield  latex  on  tapping  during  every  week  of  the  year,  in  some 
districts  there  are  periods  when,  on  account  of  the  small  yield 
obtainable,  tapping  is  partially  if  not  entirely  suspended.  Some 
companies  have  even  considered  the  stopping  of  tapping  opera- 
tions during  the  greater  part  of  the  dry  period  in  each  year.  It 
has  been  previously  pointed  out  that  in  many  of  the  Hevea  districts 
of  Ceylon  there  is  a  marked  dry  period  extending  in  each  year 
from  January  to  April.  Furthermore,  during  this  season  the 
trees  drop  their  old  leaves  and  produce  new  leaves,  and  subse- 
quently flowers,  this  foliar  change  being  particularly  noticeable 
during  February  and  March.  During  this  period  the  yield  of 
latex,  and  generally  also  of  dry  rubber,  per  tapping,  is  small ; 
and  it  has  become  a  custom  on  many  estates  to  allow  the  trees 
to  rest.  On  the  other  hand,  the  interference  with  tapping  opera- 
tions by  rains  is  indicated  at  two  periods  of  the  year,  the  first 
about  June,  the  second  in  November.  Of  course,  there  is  some 
degree  of  variation  from  year  to  year  in  the  incidence  of  the 
seasons,  and  between  different  districts. 

Monthly  Returns  from  Two  Ceylon  Estates. 
The  periodical  decreases  in  jdeld  are  demonstrated  by  the 
following  returns  from   (i)   an  estate  in  the  Kelani  Valley  and 
(2)  an  estate  in  the  Matale  district : — 

Monthly  Yields  of  Rubber. 


Kelani 

Matale 

.  Kelani 

Matale 

Estate. 

Estate. 

Estate. 

Estate. 

1909. 

lb. 

lb. 

igio. 

lb. 

lb. 

January 

— 

2.744 

January 

500 

3.055 

February 

— 

2.375 

February 

— 

2,232 

March 

174 

2,343 

March 

70 

1,911 

April 

351 

1,309 

April 

910 

2,277 

May 

180 

1,096 

May 

1.322 

567 

June 

44 

752 

June 

1,085 

5.566 

July 

70 

1.269 

July 

1,664 

3.517 

August 

412 

2,166 

August 

1.783 

3.965 

September 

1.274 

2,019 

September 

2,210 

4,106 

October 

1,280 

2,342 

October 

2,598 

4,702 

November 

1,001 

1,610 

November 

3,070 

4.174 

December 

1,230 

2,897 

December 

4.146 

4,728 

512  PARA     RUBBER 

The  crops  from  the  Kelani  Valley  estate  decreased  greatly 
during  the  first  three  months  of  igio.  A  recovery  followed  in 
April  and  May  ;  this  was  in  turn  followed  by  a  set-back  in  June, 
one  of  the  rainy  months.  During  the  rest  of  the  year  there  was  a 
steady  increase  with  the  increase  in  age  and  number  of  tapped 
trees.  Note  the  fall  at  the  beginning  of  191 1.  If  one  goes  back 
to  the  yields  for  the  year  1909,  one  can  see  how  marked  has  been 
the  effect  of  the  first  rainy  season  about  the  months  of  June  and 
July,  and  how  the  second  rainy  season  has  interfered  with  tapping 
in  November.  The  returns  from  the  Matale  estate  are  less 
instructive,  owing  to  some  irregularity  in  tapping  arising  partly 
from  the  enforced  resting  of  trees.  The  typical  dry-season 
decrease  is  shown  at  the  beginning  of  each  year,  but  in  1909  there 
was  no  recovery  shown  in  the  April  returns,  and  the  decrease  was 
continued  to  the  rainy  month  of  June,  after  which  was  a  recover}'. 
In  the  year  1910,  tapping  in  the  month  of  April  showed  an  im- 
provement after  the  dry  season,  and  from  the  rains  the  crops 
during  the  month  of  May  suffered  the  most ;  but  there  is  an 
inexplicable  return  for  June,  after  which  there  is  a  gradual  rise 
in  the  crop.  In  both  years  the  November  crop  has  been  affected 
by  the  rains. 

While  it  is  impossible  to  predict  the  actual  percentage  of  the 
year's  crop  that  may  be  expected  during  any  specified  part  of 
the  year  until  the  whole  island  is  in  fuU  production,  it  seems  fairly 
safe  to  estimate  that  the  produce  from  the  same  trees  will  probably 
be  approximately  35  to  40  per  cent,  for  the  months  from  January 
to  June  inclusive,  and  60  to  65  per  cent,  from  July  to  December. 

Crop  Periodicity  in  Malay.'^. 

On  many  estates,  even  in  Malaya,  with  its  less  marked  climatic 
variations,  tapping  is  not  so  vigorously  carried  on  during  February 
and  March  as  at  the  end  of  the  year,  on  account  of  the  prevalent 
belief  that  the  trees,  while  passing  through  their  change  of  leaf, 
jdeld  less  and  require  comparative  rest.  As  a  matter  of  fact,  the 
food  reserves  drawn  upon  during  active  leaf  production  are  more 
Hkely  to  be  those  in  the  twigs  and  branches  than  those  in  the  trunk 
of  the  tree.  The  turgidity  of  the  cells,  upon  which  a  copious  flow 
of  latex  largely  depends,  is  probably  most  irregular  during  this 
period  on  account,  firstly,  of  the  check  to  transpiration  due  to 
the  death  and  fall  of  old  leaves,  and,  secondly,  on  account  of  the 
rapid  increase  in  transpiration  from  the  young  leaves  which 
usually  appear  within  a  few  days  of  the  fall  of  the  old  ones. 

We  cannot  expect  to  find  so  marked  a  variation  in  the  Malayan 
crops,  for  the  good  reason  that  seasonal  changes  have  a  much 
smaller  range ;  the  rainfall  is  more  equally  distributed,  so  that  the 
variation  in  outturn  from  month  to  month  is  comparatively 
little.  And  the  range  of  variation  being  so  comparatively  small, 
such  disturbing  factors  as  the  irregular  resting  of  trees  and  the 


PARA     RUBBER 


313 


bringing  of  young  trees  into  the  tapping  round  make  the  statistics 
somewhat  erratic. 

Monthly  Returns  of  Representative  Companies. 

To  discover  what  are  the  variations,  the  monthly  returns 
of  some  31  Malayan  companies  turning  out  large  crops  have  been 
totalled.  Of  these  companies  the  returns  for  three  years — 1908- 
1910 — have  been  available  in  four  cases,  for  two  years — 1909-1910 — 
in  six  cases,  for  one  year — 1910 — in  twenty-one  : — 


Total 

Increase  or 

Total 

Increase  or 

Crops. 

decrease. 

Crops. 

decrease. 

lb. 

lb. 

lb. 

lb. 

January 

•       857.258 

July 

:, 139,817 

+  135.295 

February 

.      843,876 

—  13.382 

August 

1. 140.359 

4-          542 

March 

•      955.795 

+  111,919 

September 

1. 174.497 

+     34.138 

April 

.      921,444 

—  34.351 

October 

1.233.159 

+     58,662 

May 

■       949.553 

4-   28,109 

November 

1,290,285 

4-     57.126 

June 

.    1,004,522 

+   54.969 

December 

1,468,286 

4-  178,001 

There  is  a  fall  in  February,  with  a  strong  recovery  the  next 
month,  and  a  fall  in  April.  Yet,  in  spite  of  this,  April  shows  a 
good  advance  upon  January,  presumably  owing  to  the  increase 
in  number  and  size  of  the  tappable  trees.  From  April  onwards  a 
rise  increases  in  force  until  August,  when  it  receives  a  setback, 
starting  again  and  increasing  its  impetus,  as  it  were,  to  the  end  of 
the  year.  Not  shown  in  the  table  is  a  decrease  that  occurs  in 
January  as  compared  with  the  December  crop,  of  which  the  decrease 
in  February  is  a  continuation. 

The  fall  from  December  to  February  can  be  correlated  with 
a  decrease  in  the  rainfall — though  the  latter  is  not  very  marked— 
and  at  the  end  of  the  period  with  the  occurrence  of  wintering  and 
with  the  shortness  of  the  month  of  February — a  holiday  month. 
But  why  there  should  be  such  a  great  increase  in  March  is  not 
explainable,  even  by  allowing  for  the  rest  which  the  trees  receive 
in  February  owing  to  holidays.  The  decrease  in  April  may  be 
due  to  excessive  rains.  Suitable  moisture  conditions  permit 
of  better  crops  being  obtained  in  May,  June,  and  July  ;  but  the 
dry  season,  if  not  the  setting  of  the  fruits,  affects  the  August 
crop.  After  this  month  the  upward  move  is  resumed,  not  to  any 
great  extent  during  the  rains  in  October  and  November,  there 
being  a  slight  hesitation  during  the  latter  month  ;  then  comes  a 
big  advance  in  December,  a  more  desirable  month  for  tapping. 


Monthly    Returns    of  Two  Malayan  Companies. 

To  take  the  returns  of  separate  companies  only  is  to  increase 
the  possible  disturbing  effect  of  other  factors,  but  by  so  doing 
we  are  able  to  include  some  returns  for  the  first  three  months 
of  last  year.  There  is  a  purpose  in  this,  for  it  enables  us  to  illustrate 
the  depressing  result  on  the  yield  exercised  by  such  unprecedented 
drought  as  that  through  which  Malaya  was  then  passing. 


314 


PARA     RUBBER 


I9I0. 

Labu. 

H.  &L. 

1911. 

Labu 

H.  &L. 

January 

12,863 

43.176 

January 

20,089 

49,492 

February      . 

9,300 

40,724 

February     . 

17.872 

44.936 

March 

16,000 

47.273 

March 

14.717 

37.402 

April 

14.750 

42.265 

April 

14.569 

37,157 

May 

17,185 

38,648 

May 

20,744 

44.431 

June 

19,134 

37.471 

June 

20,635 

44,701 

July 

16,626 

39,266 

July 

23,510 

49,433 

August 

15.426 

39.8+7 

September  . 

20,648 

43.173 

October 

20,000 

48,253 

November   . 

20,000 

49.477 

December    . 

20,500 

45.908 

These  returns  are  alike  in  that  in  1910  the  months  of  February 
and  April  show  decreases  on  the  preceding  months,  though  it  must 
be  understood  that  this  is  far  from  being  the  case  with  all  the 
companies  whose  crops  have  been  totalled  in  the  preceding  table. 
The  first  of  the  two  companies  had  an  actual  decrease  in  August, 
following  another  in  July ;  the  other  shows  merely  a  hesitation 
in  the  rise.  Upon  passing  to  the  statistics  for  1911,  we  find  on 
the  whole  an  increase  in  January,  but  afterwards  a  very  marked 
decrease,  the  respective  managers  cabling  home  that  the  drought 
was  severe.  Of  course,  this  is  an  exceptional  condition,  but  the 
figures  serve  to  drive  home  the  fact  that  moisture  conditions 
affect  crops. 

Producing   Capacity    of    Plantations. 

The  following  tables  should  prove  useful  when  estimates  are 
being  made  of  future  plantation  crops  : — 

Approximate  Yield  per  Acre. 


Number 

l-lb 

I -lb. 

ij-lb. 

2-lb. 

3-lb. 

4-lb. 

Distance. 

of  trees 

per 

per 

per 

per 

per 

per 

per  acre. 

tree. 

tree. 

tree. 

tree. 

tree. 

tree. 

feet. 

lb. 

lb. 

lb. 

lb. 

lb. 

lb. 

10  by  10 

435 

326 

435 

652 

870 

1.305 

— 

10  by  15 

290 

217 

290 

435 

580 

870 

1,160 

15  by  15 

193 

145 

193 

— 

386 

579 

772 

15  by  20 

145 

109 

145 

217 

290 

435 

580 

20  by  20 

109 

82 

109 

163 

2X8 

327 

436 

20  by  25 

87 

65 

87 

130 

174 

261 

348 

25  by  25 

70 

52 

70 

105 

140 

210 

280 

Table 

Showin 

G    THE 

Producing 

Capac 

ITY    OF    Pl 

ANTATIONS. 

At 

I  cwt. 

At  2  cw1 

At  3  cwt. 

At  4  cwt 

Acreage. 

per 

acre. 

per  acre 

per  acre. 

per  acre. 

tons. 

tons. 

tons. 

tons. 

100 

5 

10 

15 

20 

210 

12i 

25 

37i 

50 

500 

25 

50 

75 

100 

1,000 

50 

100 

150 

200 

10,000 

500 

1,000 

1,500 

2,000 

50,000 

2 

500 

5,000 

7,500 

10,000 

IC0,OO0 

5 

000 

10,000 

15,000 

20,000 

200,000 

10,000 

20,000 

30,000 

40,000 

350,000 

17.500 

35,000 

52.500 

70,000 

The   second    table 

may    be    serviceable    wh 

?n    yields    from 

countries 

laving 

a    known    acreage    under    Hev  a    are    beine 

estimated. 

CHAPTER  XX. 

PHYSICAL  AND  CHEMICAL  PROPERTIES  OF  LATEX. 

The  Physical  Properties  of  Latex. 

The  latex  of  Hevea  hrasiliensis,  as  it  flows  from  a  freshly-made 
incision,  is  white  or  pale  yellow  in  colour,  and  varies  in  consis- 
tency mainly  according  to  whether  drought  or  rainy  weather 
prevails.  It  is  slightly  alkaline  when  fresh,  and,  as  it  flows  from 
the  tree,  consists  of  minute  globules  of  caoutchouc  and  other 
bodies  suspended  in  a  liquid  containing  various  materials  in 
solution  and  a  varying  proportion  of  mechanical  impurities.  In 
the  opinion  of  most,  it  is  strictly  comparable  with  an   emulsion. 

The  latex  obtained  from  the  first  incisions  usually  contains  a 
large  proportion  of  sap  exudations,  which  cannot  be  excluded  as 
they  flow  from  the  freshly-cut  cortical  cells  ;  they  can  be  reduced 
by  incising  instead  of  excising  the  laticiferous  tubes.  In  several 
instances  the  latex,  by  mixing  with  such  exudations,  becomes 
neutral,  and  may  rapidly  develop  acid  properties.  The  conversion 
to  an  acid  state  is  followed  by  coagulation,  and  hence  the  first 
tappings  are  frequently  but  unavoidably  accompanied  by  a  large 
proportion  of  scrap. 

Specific  Gravity  of  Latex. 

The  chemical  composition  of  latex  varies  considerably  arid  a 
difference  in  specific  gravity  is  therefore  to  be  expected.  Mus- 
pratt  gives  the  density  at  i-oi2  ;  Ule  quotes  1-041  ;  Henri  0-973  ; 
Seeligmann  i-oig  ;  while  Bamber  states  that  the  specific  weight 
of  latex  of  Hevea  hrasiliensis  containing  32  per  cent,  of  caoutchouc 
is  1-018  at  6o°F. 

By  Beadle  and  Stevens  (Indiarubber  Exhibition  Lectures, 
1908),  it  was  stated  that  one  of  them  determined  the  specific 
gravity  of  a  large  number  of  samples  of  latex  from  8-year-old  trees. 
The  average  was  0-975,  the  lowest  record  being  0-973,  and  the 
highest  0-980.  Kaye  made  a  number  of  determinations,  and 
found  a  maximum  of  10046  and  a  minimum  of  1-0030.  Ac- 
cording to  Girard  and  Lindet,  the  density  is  0-986.  In  the  case 
of  latex  collected  in  the  Manaos  district,  Bonnechaux  found  a 
density  of  0-905. 

The  density  of  the  caoutchouc  itself  varies,  though  the 
differences  observable  in  that  compound  are  insignificant  when 
compared  with  those  of  the  mineral,  protein,  or  resinous  contents. 

The  Chemistry  of  the  Latex. 

The  object  of  the  producer  in  the  tropics  is  to  separate  the 
globules  of  caoutchouc  from  the  mechanical  impurities  and  some  of 


3i6  PARA     RUBBER 

the  materials  in  solution  ;  it  is,  therefore,  necessary  to  explain 
clearly  what  these  substances  are  and  their  general  characteristics^ 

The  planter,  who  aims  at  producing  the  highest  quality  of 
rubber  or  perfecting  the  chemical  and  mechanical  processes  in- 
volved in  its  manufacture  from  latex,  must  thoroughly  grasp  the 
nature  of  the  substances  he  has  to  deal  with. 

The  mechanical  impurities  present  in  most  samples  of  latex  in 
the  field  consist  of  pieces  of  bark,  fibre,  sand,  &c.,  and  may  be 
easily  separated  by  filtering  the  diluted  solution  through  butter 
cloth  or  fine  gauze. 

The  filtrate  from  such  material  is  composed  of  water,  caout- 
chouc, resins,  proteins,  sugars,  gums,  insoluble  substances,  and 
mineral  matter.  The  amount  of  water  in  pure  latex  varies  con- 
siderably, but  it  is  usually  estimated  at  50  to  60  per  cent.  The 
latex  from  trees  which  have  been  frequently  or  heavily  tapped 
usually  contains  a  much  higher  proportion  of  water,  in  some 
instances  even  as  much  as  90  per  cent,  of  water  being  present.  The 
latex  collected  during  the  dry  months  of  February  and  March  at 
Henaratgoda  contains  much  less  water  than  that  obtained  from 
the  same  trees  in  the  rainy  season.  The  following  table  will 
serve  to  indicate  the  general  range  in  composition  according  to 
the  analyses  of  Seeligmann  (Indiarubber  and  Gutta  Percha,  by 
Torrilhon,  Seehgmann,  and  Falconet),  Lascelles  Scott  and  Bamber 
(Circular  R.B.G.,  June,  1899)  : — 

Scott.  Bamber. 

0/  0/  0/ 

/o  /o  /o 

52-32         ■■  5515  55"56 

37-13         ..  41-29  32-00 

2-71  .  .  2'lS  2-03 

344         -  -  —  203 

0-23         .  .  0-41  .  — 

417  -  0'36  — 

The  above  analyses  show  the  general  composition  of  the 
latex  of  Hevea  hrasiliensis  and  the  different  classifications  adopted 
by  chemists.  The  analysis  by  Lascelles  Scott  is  one  of  a  latex  of 
unnamed  origin,  but  ^^'ebe^  accepted  it  as  being  not  far  from  the 
truth  for  our  species.  There  is  an  indefiniteness  about  several 
of  the  constituents  grouped  under  such  general  heads  as  proteins, 
resins,  etc. 

V.-vRiATioN  IN  Composition  of  Hevea  Latex. 

The  latex  from  parts  of  the  same  tree  at  different  times  of  the 
year  shows  considerable  variation,  and  minor  ingredients,  normally 
absent,  appear  on  certain  occasions.  It  has  also  been  shown 
elsewhere  how  the  composition  and  character  of  the  latex  from 
the  same  tree  varies  during  different  parts  of  the  same  season, 
according  to  the  frequency  of  tapping,"  conditions  of  humidity, 
and  the  age  of  the  cortex  whence  the  latex  is  extracted.  Schid- 
rowitz,  Kaye,  and  Stevens  have  shown  how  certain  samples 
of  latex  from  trees  of  Hevea  hrasiliensis  in  Ceylon  vary,  and  have 
pointed  out  that  in  those  which  they  characterised  as  abnormal 
only  from  4  to  10  per  cent,  of  caoutchouc  occurred. 


Seeligmann, 

% 

Water       .  . 

•  •       55  to  56 

Caoutchouc 

32 

Proteins    .  . 

2-30 

Resins 

Traces 

Ash 

— 

Sugar 

— 

PARA     RUBBER  317 

It  will  be  noticed  that  the  caoutchouc,  according  to  the  above 
analyses,  varies  from  32  to  over  41  per  cent.,  and  the  other  con- 
stituents such  as  resin,  sugar,  insoluble  substances  and  ash,  show 
considerable  variation.  This  is  not  surprising,  as  the  latex  ex- 
amined in  each  case  was  obtained  from  a  different  country,  and 
the  ages  of  the  trees  were  probably  quite  different.  Furthermore, 
the  methods  of  extraction  of  the  latex  involve  the  cutting  of  bark 
tissues  to  different  .depths,  and  the  inevitable  mixing  of  liquids 
would  account  for  much  variation  in  the  soluble  impurities. 

The  Caoutchouc  Hydrocarbon. 

The  caoutchouc  exists  as  globules  in  suspension.  When  pure 
it  is  practically  colourless,  and  is  much  lighter  than  water.  It 
consists  essentially  of  carbon  and  hydrogen,  and  belongs  to  a 
class  of  bodies  known  asterpenes,  of  which  turpentine  is  a  member. 
The  percentage  composition — C,„  H,,, — is  the  same  for  turpen- 
tine as  for  the  caoutchouc  hydrocarbon,  though  the  degree  of 
condensation,  as  indicated  by  the  molecular  weight,  is  much 
higher  in  the  latter.  Caoutchouc  is  insoluble  in  water.  According 
to  Weber  it  may  be  obtained  fairly  pure  by  making  a  benzene 
solution,  allowing  the  insoluble  matter  to  settle  out,  and  sub- 
sequently precipitating  the  rubber  from  the  clear  solution  by  the 
addition  of  alcohol. 

Henri  states  that  microscopic  examination  of  the  latex  reveals 
the  presence  of  a  large  number  of  globules,  some  with  a  diameter  of 
nearly  0-002  millimetres,  others  smaller,  the  latter  exhibiting 
extremely  intense  and  persistent  Brownian  movements.  The 
number  of  globiiles  in  a  latex  indicates  its  richness  and  may  be 
easily  determined  ;  in  the  operation  a  suitable  diluent — 20  per 
cent,  solution  of  sodium  chloride — is  added,  which  arrests  the 
Brownian  movements,  without  precipitating  or  coagulating  the 
latex  ;  the  globules  can  then  be  counted,  and  in  one  case  an  average 
of  50  milhon  globules  per  cubic  millinietre  was  estimated. 

According  to  Seeligmann,  the  average  diameter  of  the  globules 
is  0-0035  mm.  This  size  seems  to  be  greater  than  that  of  the 
globules  in  any  other  latex.  Henri  asserts  that  the  diameter 
varies  only  between  0-0005  mm.  and  0-002  mm. 

The  origin  of  caoutchouc  in  latex  has  been  investigated 
by  many  authorities,  and  considerable  doubt  still  exists  in  the 
minds  of  chemists  regarding  this  ;  nevertheless,  it  is  generally 
admitted  that  Harries  has  fairly  well  established  a  close  relation- 
ship between  the  caoutchouc  and  the  sugar-like  products — 
laevulinic  acid — in  the  plants. 

Resins  and  Sugary  Substances. 

The  resins,  gums,  and  oil  suh*itances  are  present  in  varying 
quantities.  Generally  the  latex  i\om  young  trees,  branches,  and 
twigs  contains  a  large  proportion  ,6f  these  substances  ;  they  may 
occur  as  globules  suspended  in  tjie  latex  or  in  solution.  In  the 
ordinary  processes  of  coagulatioi.  the  greater  part  of  the  resin 


3i8  PARA     RUBBER 

becomes  an  integral  part  of  the  rubber,  and  the  extraction  from 
the  latter  by  the  manufacturers  in  Europe  is  a  difificult  and  tedious 
task. 

Spence  (Indiarubber  Lectures,  1908),  remarks  that  at  one  time 
it  was  believed  the  resins  were  derived  from  other  sources  than 
the  latex  tubes,  and  he  admits  that  this  maybe  true  to  a  certain 
extent,  particularly  when  tapping  is  carelessly  done  ;  but  in 
most  cases  the  resins  in  the  coagulated  rubber  are  derived  from  the 
latex,  although  in  what  form  he  had  not  been  able  to  determine. 
They  are  probably  dissolved  in  the  caoutchouc  in  the  latex.  He 
believed  that  they  would  eventually  be  shown  to  be  related  to 
the  caoutchouc  itself  and  derived  from  this,  either  as  a  by-product 
or  as  an  intermediary  one  in  the  building-up  or  breaking-down 
of  the  caoutchouc  by  the  plant.  They  have  been  shown  to  contain 
oxygen,  an  element  that  the  caoutchouc  hydrocarbon  very  readily 
takes  up,  and  recent  investigations  have  shown  that  in  some  cases 
the  resins  extracted  from  indiarubber  resemble,  in  elementary 
composition  at  least,  certain  resinous  products  prepared  by  the 
oxidation  of  rubber  in  a  current  of  air. 

The  sugars  are  rarely  present  in  large  proportions,  and  a 
maximum  of  0-5  per  cent,  may  be  taken  as  correct.  They  are 
dissolved  in  the  liquid  in  which  the  globules  of  caoutchouc  and 
resins  are  suspended  ;  in  the  washing  of  the  freshly-coagulated 
rubber  they  are  generally  removed. 

Starch  granules  of  peculiar  shape  exist  in  latex. 

Protein    Matter. 

Our  knowledge  of  the  chemistry  of  the  proteins  in  latex  is  not 
very  clear,  especially  in  regard  to  the  soluble  nitrogenous  products 
which  remain  in  the  mother  liquor  after  coagulation  ;  these  are 
probably  quite  different  from  the  complex  proteins  which  are 
coagulated  and  form  part  of  ordinary  raw  rubber.  Spence 
states  (LR.J.,  Aug.  i6th,  1907),  that  though  the  nitrogenous 
products  which  occur  in  the  latex  after  coagulation  are  peculiar 
in  origin  and  constitution  they  are  in  all  probability  simple  pro- 
ducts of  protein  metabolism. 

The  protein  or  albuminous  matter,  about  which  more  will 
be  said,  varies  from  19  to  27  per  cent,  of  the  fresh  lartex.  or 
approximately  3  to  4  per  cent,  of  the  dried  coagulated  product. 
This  is  a  very  high  proportion,  but  from  the  analyses  quoted  above 
no  other  conclusion  can  be  drawn.  It  is  believed  that  this  pro- 
tein matter  is  of  a  complex  nature,  and,  alone  or  with  the  gums, 
sugars,-  and  enzymes,  may  be  responsible  for  the  development 
of  bacteria  on  the  finished  product  which  lead  to  putrefaction  or 
tackiness. ' '  The  use  of  formaldehyde  in  connection  with 
elimination  of  the  protein  matter  will  be  considered  when  dealing 
with  coagulation.  ; 

When  the  rubber  is  prepared  by  simple  coagulation  the 
insoluble  protein  becomes  a  part  of  the  rubber,  but  if  a  centrifugal 
method  is  adopted,  and  the  freShly-coagulated  material  frequently 


PARA     RUBBER 


319 


and  well  washed,  pressed  and  dried  quickly,  a  considerable  amount 
may  be  removed  or  rendered  less  harmful.  In  the  purification 
of  rubber  this  subject  will  be  dealt  with.  It  is  believed  that  the 
removal  of  protein-,  from  commercial  rubber,  though  sometimes 
desired,  is  almost  impossible.  In  the  perfecting  of  mechanical 
processes  and  the  use  of  antiseptic  re-agents  for  dealing  with  the 
protein  in  the  latex  as  it  comes  from  the  tree  lies  a  considerable 
amount  of  important  profitable  work  for  planters  in  the  tropics. 

Enzymes  in  Latex. 

The  latex  of  Hevea  has  not  been  completely  examined  for 
its  enzymes  (ferments),  and  some  oxidising  enzymes  are  all  that 
have  been  discovered.  These  oxidising  enzymes  are  very  im- 
portant factors.  They  are  partly  responsible  for  the  latex  turning 
acid  on  keeping.  They  have  been  accused,  without  good  reason, 
according  to  Spence,  of  inducing  ' '  tackiness ' '  in  the  dry  rubber. , 
But  what  they  can  justly  be  associated  with  is  the  darkening 
of  prepared  rubber  through  their  oxidising  action  upon  the  pro- 
teins. Spence  points  out  that  the  enzymes  merely  accelerate 
a  reaction  that  can  take  place  without  them,  though  much  more 
slowly.  Experiments  by  Fickendey  have  shown  that  oxygen 
is  essential  to  the  darkening. 

Mineral  Matter. 

The  inorganic  matter  found  in  most  latices  consists  of  com- 
pounds containing  calcium,  potassium,  iron,  sodium,  and  magne- 
sium ;  these  are  combined  with  mineral  or  organic  acids.  The 
concentration  and  nature  of  the  salts  found  in  the  latex  influence 
its  coagulation. 

The  mineral  matter  occurring  in  suspension  and  solution  in  the 
latex,  and  the  various  insoluble  compounds  indicated  in  the  analyses 
previously  quoted,  may  be  regarded  as  impurities  of  minor  im- 
portance, and  can  be  better  dealt  with  in  the  chaptere  concerned 
with  the  components  of  commercial  rubber  and  the  purification 
processes. 

Effects   of   Physical   and   Chemical   Agencies. 

The  behaviour  of  the  latex,  when  subjected  to  physical  and 
chemical  agencies,  may  here  be  touched  upon.  It  readily  mixes 
with  water  without  creaming.  Parkin  kept  some  latex  diluted 
four  times  in  an  ice  chamber  for  days  without  showing  any  signs  of 
creaming.  It  is  very  difficult  to  separate  the  caoutchouc  by 
centrifugal  force,  and  on  several  occasions  a  speed  of  over  10,000 
revolutions  per  mfnute  did  not  affect  a  separation  of  the  caoutchouc 
of  normal  Hevea  latex.  The  effect  of  freezing  was  tried  by  Parkin, 
a  mixture  of  ice  and  common  salt  being  used  to  give  the  low  tem- 
perature ;  after  thawing,  the  latex  appeared  to  be  the  same  as 
before,  and  creaming  was  not  hastened  by  the  changes  of  tem- 
perature. Addition  of  ammonia  or  formalin  prevents  or  delays 
coagulation,  the  former  by  neutralizing  the  acids  as  soon  as  they 


320  PARA     RUBBER 

are  formed,  and  the  latter  by  acting  as  an  antiseptic  and  pre- 
venting the  decomposition  of  the  protein  matter.  Acids  bring 
about  coagulation  in  the  cold,  but  the  action  is  much  quicker 
when  warmed.  The  latex  may,  however,  if  diluted,  be  boiled,  and 
yet  coagulation  is  not  brought  about. 

These  points  should  be  borne  in  mind  by  the  planter  who  is 
inclined  to  experiment  mechanically  and  chemically  with  the 
object  of  extracting  the  undesirable  substances  usually  present  in 
latex. 


CHAPTER  XXI. 

PRODUCTION  OF  RUBBER  FROM  LATEX. 

Having  briefly  described  the  physical  and  chemical  propei-ties 
of  latex,  the  operations  upon  which  the  production  of  good  rubber 
from  latex  depends  can  now  be  dealt  with.  If  pure  latex  is  allowed 
to  stand  in  a  receptacle,  it  finally  coagulates  and  the  caoutchouc 
globules  with  other  substances  float  to  the  top,  leaving  a  more  or 
less  clear  liquid  behind. 

By  the  addition  of  chemical  re-agents  and  by  subjecting  the 
latex  to  different  temperatures  coagulation  may  be  hastened  or 
retarded.  The  coagulated  substance,  after  washing,  pressing, 
and  drying,  is  ultimately  known  as  the  rubber  of  commerce. 

Keeping  the  Latex  Liquid  in  Tanks. 

On  small  estates  where  few  and  widely-scattered  trees  are 
being  tapped  the  planter  is  often  compelled  to  resort  to  the  pro- 
duction of  rubber  on  a  small  scale.  This  frequently  involves  the 
use  of  much  petty  hand  labour.  The  latex  can,  however,  be  kept 
in  a  liquid  condition  for  several  days  or  even  weeks  without 
doing  much  harm  to  the  finished  product,  and  the  rubber  can  be 
manufactured  on  a  big  scale  when  a  sufficient  quantity  of  latex 
has  been  accumulated. 

If  it  is  necessary  to  keep  the  latex  in  the  liquid  condition,  this 
can  be  done  by  the  addition  of  formalin,  ammonia,  sodium  car- 
bonate, or  other  alkaline  chemicals  which  are  readily  soluble  in 
cold  water.  It  is  better  to  use  either  ammonia  or  formalin  and 
to  avoid  any  of  the  mineral  salts  ;  the  former  can  be  readily 
removed  and  may  even  escape  on  exposure  to  the  air  in  the 
ordinary  processes  of  preparation. 

In  one  invention,  not  much  used  on  estates,  the  latex  is  kept 
in  covered  settling  tanks  supplied  with  (i)  a  drip-tin  apparatus, 
filled  with  chemicals  to  retain  the  milk  in  an  alkaline  condition,  and 
(2)  with  a  paddle  to  keep  the  latex  in  motion.  If  a  receptacle  con- 
taining ammonia  is  exposed  to  the  air,  the  re-agent  will  evaporate 
and  the  latex  coagulate  within  a  few  days.  If,  however,  the 
receptacles  are  covered  or  sealed,  the  ammonia  cannot  easily 
escape  and  the  latex  can  be  accumulated  in  a  liquid  state  almost 
indefinitely. 

Formalin  has  a  similar  effect,  as  it  stops  putrefaction  and 
therefore  prevents  the  development  of  acidity.  The  ammonia 
probably  neutralizes  the  acids  as  they  are  formed  and  thus  main- 
tains the  latex  in  an  alkaline  or  neutral  state,  thereby  preventing 
coagulation.  By  the  use  of  such  re-agents  and  apparatus  a  great 
saving  of  labour  may  be  effected. 

u 


322  PARA     RUBBER 

It  is  reported  by  Messrs.  Clayton  Beadle  and  Stevens  that  the 
use  of  formalin  in  the  latex  does  not  affect  the  quality  of  the 
rubber.     But  Schidrowitz  and  Kaye  have  a  different  opinion. 

Effects  of  Diluting  the  Latex. 
It  has  been  asserted  that  the  protein  and  resin  content  of  the 
prepared  rubber  can  be  Icept  low  by  dilution  of  the  latex  before 
coagulation.  This  can  only  refer  to  proteins  and  resins  of  such 
kinds  as  remain  in  the  mother  liquor  after  separation  of  the  rubber, 
and  which  also,  of  course,  are  present  in  the  water  (mother  liquor) 
retained  in  the  rubber  itself.  When  the  rubber  is  dried,  they  are 
left  behind  in  it.  The  effect  of  dilution  is  to  lessen  their  concen- 
tration in  the  mother  liquor  retained  in  the  rubber,  so  that  they 
are  left  behind  in  smaller  quantity  on  evaporation  of  the  water. 
Yet  an  evil  effect  of  dilution  is  apparently  a  loss  in  quality  of  the 
rubber. 

Straining  Latex  :  Centrifugal  Machines. 

Before  any  steps  are  taken  to  effect  coagulation,  the  planter 
should  see  that  the  latex  is  quite  free  from  any  mechanical  im- 
purities ;  it  is  first  necessary  to  filter  the  latex  through  porous 
cloth  or  horsehair  sieves  or  to  remove  the  -visible  impurities  by 
means  of  some  mechanical  apparatus. 

A  very  important  reason  for  straining  latex  in  the  field  is  that 
the  coagulated  scrap  will  thereby  tend  to  be  on  the  whole  cleaner  ; 
furthermore,  the  prompt  exclusion  of  mechanical  impurities  in 
the  field  appears  to  be  accompanied  by  a  reduction  in  the  quantity 
of  scrap  normally  appearing  in  latex  as  irregular  coagulated 
lumps. 

At  the  Ceylon  Rubber  Exhibition  two  centrifugal  machines 
were  exhibited  for  this  work,  and  the  following  is  the  account  given 
in  the  Official  Handbook  of  the  Exhibition. 

' '  Both  machines  are  rotary,  and  with  the  exception  of  the 
•central  basket  or  drum,  are  of  the  same  design,  but  with  the  one 
type  of  drum  only  the  larger  and  hghter  impurities  can  be  removed, 
whilst  with  the  other  type  only  those  particles  of  sand  and  grit, 
etc.,  are  eliminated  which  are  of  a  greater  specific  gravity  than 
that  of  the  latex. 

"Mr.  Macadam's  exhibit,  i.e.,  the  one  which  removes  the 
larger  and  lighter  impurities  from  the  latex,  is  a  12-inch  self- 
balanced  centrifugal  machine  with  a  rope  drive  ;  it  is  composed 
of  a  cast-iron  pedestal  surmounted  by  a  cast-iron  casing  with  a 
dished  bottom  and  outlet  lip,  the  top  being  fitted  with  a  cover 
having  a  funnel  in  the  centre  for  the  purpose  of  feeding  the  machine. 
Inside  this  casing  a  basket  or  perforated  drum  revolves,  being 
actuated  by  a  vertical  shaft  whose  bearings  are  in  the  neck  and 
foot  of  the  pedestal.  The  basket  is  not  compelled  to  revolve 
about  a  fixed  centre  as  in  other  machines,  but  is  permitted  to  find 
its  proper  centre  of  rotation  by  the  use  of  elastic  bearings,  thus 
reducing  to  a  minimum  the  power  required  to  drive  the  machine 
as  also  the  amount  of  vibration  transmitted  to  the  casing  of  the 


PARA     RUBBER  323 

machine.  The  vertical  shaft  is  driven  at  the  rate  of  three  thousand 
revolutions  per  minute  by  means  of  a  rope  drive  from  a  small 
countershaft  carried  by  swing  bush  bearings  mounted  on  a  cast 
iron  frame.  The  shaft  is  also  fitted  with  fast  and  loose  pulleys 
for  belt  driving.  The  lubrication  of  the  swing  bush  bearings  of 
the  countershaft,  as  well  as  of  the  bearings  in  the  machine  proper, 
are  most  efficient,  the  former  being  self -oiling  and  the  latter  being 
fed  from  an  oil  cup  and  tube  outside  of  the  casing  and  pedestal. 
The  machine  is  fitted  with  a  suitable  foot  brake  to  enable  the 
operator  to  stop  the  process  at  any  moment.  The  machine  was 
thoroughly  tested  by  passing  latex  which  had  been  freely  and 
well  mixed  with  sand,  lumps  of  earth,  chips,  twigs,  bark,  etc., 
through  the  funnel  in  the  top  lid  of  the  outer  casing  and  into  the 
centre  of  the  revolving  basket  or  perforated  drum.  Inside  the 
latter  is  placed  a  linen  or  cloth  bag,  and  it  is  through  this  that  the 
latex  is  rapidly  strained,  leaving  the  lighter  and  large  impurities 
behind  it.  The  strained  latex  then  passes  into  the  outer  casing 
and  finally  issues  from  the  pipe  at  the  side  into  a  receptacle  bowl. 
By  this  means  large  quantities  of  latex  can  be  strained  in  a  very 
short  time. 

"The  machine  takes  about  i  H.P.  to  drive,  and  its  output 
is  50  gallons  per  hour. ' ' 

The  writer  was  informed,  when  at  Culloden  in  April,  1908, 
that  the  machine,  though  useful,  had  not  been  much  used  by  Mr. 
Macadam — or  any  other  planters  in  Ceylon. 

' '  The  machine  shown  by  Mr.  Kelway  Bamber  is  much  the 
same  as  that  exhibited  by  Mr.  Macadam,  except  that  no  cloth  bag 
is  used  and  that  the  bottom  and  the  periphery  of  the  drum  are 
solid,  and  the  top  also  is  partly  closed. 

' '  The  latex  is  poured  into  a  funnel  in  the  lid  in  the  same 
manner  as  that  described  in  the  other  machine,  except  that  it  has 
to  be  very  carefully  and  slowly  fed  into  the  centre  of  the  revolving 
•drum.  The  heavier  particles  of  the  impurities  in  the  latex  are 
thrown  centrifugally  against  the  periphery  and  are  there  collected 
and  retained,  being  helped  somewhat  by  means  of  short  partitions, 
whilst  the  pure  latex  rises  over  the  top  of  the  drum  into  the 
outer  casings  and  then  finally  issues  from  a  pipe  into  a  receptacle 
below.  The  output  of  the  machine  is  roughly  estimated  at  20 
gallons  per  hour. ' '  Having  secured  latex  free  from  any  mechanical 
impurities  the  first  step  towards  the  production  of  crude  rubber 
is  coagulation. 

Sieve  Pails. 

Where  centrifugal  machines  are  not  used'  the  majority  of 
estates  collect  the  latex  in  enamelled  pails  provided  with  tight- 
fitting  hds.  The  latter  are  furnished  with  metal  sieves,  having  a 
very  small  mesh,  which  are  effective  in  removing  mechanical 
mpurities  from  the  latex.  Sieves  of  this  description  are  expensive, 
and  are  liable  to  be  clogged  with  small  particles  of  coagulated 
rubber.  Hence  the  necessity  to  clean  them  regularly  at  the  end 
of  a  day's  work. 


324  PARA     RUBBER 

Transport  of  Latex  to    the   Factory. 

The  latex  collected  in  the  enamelled  pails  may  be  conveyed 
in  these  receptacles  to  the  factory  or  accumulated  in  larger  vessels 
and  transported  as  latex  or  coagulated  rubber  to  the  factory. 
The  idea  of  preparing  the  latex  in  the  field,  small  sheds  being  pro- 
vided with  the  usual  apparatus  for  straining  and  coagulating,  is  by 
no  means  new.  It  was  first  suggested  to  me  by  Mr.  Golledge 
in  1908.  The  object  is  to  reduce  the  transport  difficulties  by 
removing  the  water,  or  as  much  of  it  as  possible,  on  the  spot. 
Even  then  the  transport  of  the  freshly-coagulated  rubber  may 
occasion  some  difficulty  on  large  estates  provided  with  only  one 
central  factory.  On  Lanadron  and  other  estates  in  the  East,  the 
monorail  has  been  used  for  transporting  latex  from  the  field  to 
the  factory ;  on  other  properties  light  railways  have  been  constructed 
to  do  the  same  work.  Where  monorails  are  not  used,  it  is  often 
found  convenient  to  convey  the  latex  in  large  metal  tanks 
supported  on  two  wheels — the  whole  being  easily  pushed  by  one 
cooly. 

Monorails  and  Light  Railways. 

The  system  known  as  Caillet's  monorail  has  found  favour 
on  many  plantations.  This  is  intended  as  an  intermediary 
between  carts  and  the  lightest  of  double  rail  systems.  It  is 
essentially  a  system  for  small  traffic,  and  the  maximum  limit  of 
its  economical  working  varies  from  150  to  200  tons  per  day, 
according  to  local  conditions.  It  is  especially  economical  where 
long  distances  have  to  be  traversed  and  the  traffic  amounts 
to  only  a  few  thousand  tons  per  annum. 

It  consists  of  a  single  rail  of  light  section  supported  by  steel 
sole-plates  at  intervals  of  a  few  feet,  and  is  laid  down  direct  on  the 
surface  of  the  ground,  without  sleepers,  ballasting  or  other  special 
preparation.  One  horse  is  required  for  each  truck,  and  can 
draw  a  load  of  ij  to  2  tons  over  a  line  where  the  gradient  does 
not  exceed  about  5  per  cent.  Several  trucks  can  be  coupled 
together,   thereby  reducing  the  number  of  drivers. 

The  cars  for  hand  traction  are  hght  and  easily  manipulated, 
and  one  man  can  work  10  hours  per  day  transporting  loads  of 
6  cwt.  The  bottom  of  the  cars  being  only  a  few  inches  above 
the  rail,  it  is  impossible  for  them  to  run  away  or  to  overturn. 

A  hght  section  of  rail  is  used,  a  g-lb.  rail  being  sufficient  for 
all  cars  on  two  wheels  with  a  load  up  to  15  cwt.  and  for  bogie  cars 
with  a  load  of  about  20  cwt.  As  the  weight  of  the  load  presses 
directly  upon  the  top  of  the  rail,  only  sufficient  strength  is 
required  to  resist  any  permanent  bending  of  the  rail.  For  trucks 
loaded  up  to  30  cwt.,  a  12-lb.  or  14-lb.  section  is  employed  according 
to  the  amount  of  traffic  per  day.  The  14-lb.  section  is  also  strong 
enough  for  bogie  trucks  carrying  a  4-ton  load. 

Light  railways  have  also  been  laid  down  in  Java  which  are 
said  to  be  serviceable  as  a  means  of  transporting  large  cans  of 
latex  as  well  as  the  finished  product. 


PARA     RUBBER  325 

Natural  or  Spontaneous  Coagulation. 

If  latex  is  allowed  to  stand  exposed  to  air,  coagulation  takes 
place  after  an  interval  of  from  6  to  24  hours.  The  coagulated 
substance  carries,  or  becomes  mixed  with,  the  suspended  globules 
of  caoutchouc  and  other  bodies,  so  that  the  whole  process  is 
more  or  less  one  of  clarification,  the  liquid  left  behind  usually 
containing  only  those  ingredients  of  the  latex  which  have  remained 
in  solution.  Coagulation  occurs  as  soon  as  the  latex  becomes 
neutral  or  faintly  acid,  no  matter  what  proportion  of  suspended 
globules  of  caoutchouc  or  other  constituents  may  be  present  in 
the  latex. 

The  natural  method  of  coagulation  depends  upon  the  formation 
of  acids  by  bacteria  from  proteins  and  carbohydrates  present  in 
the  latex. 

It  has  been  asserted  that  the  rubber  made  by  the  natural 
method  is  less  elastic.  Other  objections,  viz.,  the  slowness  of  the 
method  ;  the  gathering  of  impurities  ;  and  the  putrefaction  that  is 
begun  in  the  rubber  and  is  an  essential  condition  for  the  process 
of  coagulation,  have  been  raised.  Furthermore,  the  mother 
liquor  is  often  quite  turbid  owing  to  its  containing  a  quantity  of 
caoutchouc.  If  such  mother  liquor  is  thrown  away,  there  is  con- 
siderable waste.  The  caoutchoac  can  be  obtained  from  such 
liquids  by  the  addition  of  acetic  acid. 

Artificial  Methods  of  Coagulation. 

There  are  numerous  mechanical  and  chemical  processes  by 
means  of  which  rubber  can  be  obtained  from  latex. 

Until  the  various  theories  outlined  elsewhere  have  been 
definitely  proved  and  accepted,  we  can  best  regard — in  a  work 
such  as  this,  which  is  written  for  the  guidance  of  the  practical 
planter — some  of  the  protein  substances  as  playing  an  important 
part  in  coagulation.  Certain  proteins  remain  in  solution  even  after 
coagulation  ;  others  are  capable  of  being  converted  into  an 
insoluble  form  and  occur  in  all  rubbers. 

Heating  Methods. 

Some  kinds  of  latex  can  be  heated  for  a  long  time — almost 
indefinitely — without  coagulation  being  effected,  whereas  other 
kinds  coagulate  rapidly  on  the  application  of  heat. 

According  to  Parkin,  the  diluted  latex  of  Hevea  brasiliensis  is 

unaffected  by  boiling.     If  the  undiluted  latex  is  boiled,  water  is 

driven  off,  and  the  thickened  milk  may  then  become  charred.     The 

^separation  of  the  caoutchouc  of  Castilloa,  Ficus  and  Landolphia 

latices  is  often  effected  by  boiling  on  a  slow  fire. 

The  addition  of  certain  chemical  re-agents  to  the  heated  latex 
brings  about  coagulation  ;  dilute  mineral  acids,  acetic  acid,  and 
tannic  acid  are  particularly  active. 

Natural  Heat. 

Explorers  who  have  visited  American  and  African  rubber- 
producing  areas  report  that  the  natives  frequently  collect  the 


326  PARA     RUBBER 

latex  and  rub  it  over  their  arms  and  chests  and  allow  the  heat 
of  the  body  and  the  feebly  acid  perspiration  to  aid  in  the  produc- 
tion of  rubber.  The  thin  particles  thus  obtained  are  gathered  and 
made  up  into  balls  for  export. 

Addition  of  Water. 
The  addition  of  pure  water  to  the  latex  of  Hevea  hrasiliensis 
does  not  hasten  coagulation,  but,  as  in  the  case  of  many  other 
latices,  delays  the  formation  of  a  solid  clot  for  a  considerable  time. 
It  is  worthy  of  note,  however,  that  the  caoutchouc  of  Castilloa  is 
sometimes  agglutinated  by  the  addition  of  water,  and  one  report 
states  that  the  same  result  is  sometimes  obtained  when  the  latex 
of  Funtumia  elastica  is  similarly  treated.  The  caoutchouc  in  both 
these  latices  can  be  creamed  or  separated  by  means  of  a  centrifugal 
machine. 

Addition  of  Plant  Juices. 

Organic  or  mineral  acids  bring  about  the  coagulation  of 
the  latex  of  Hevea  hrasiliensis.  In  parts  of  Ceylon  some  very 
interesting  results  have. been  obtained  by  the  use  of  clear  aqueous 
solutions  of  citrus,  tamarind,  and  other  commonly-occurring  acid 
fruits.  Samples  of  perfectly  dry  plantation  rubber,  obtained  by 
adding  plant  juices  to  the  latex,  have  possessed  remarkable  strength. 
In  parts  of  tropical  America  and  Africa  these  re-agents  are  largely 
used,  and  many  believe  that  the  strength  of  the  coagulated  rubber 
is  much  improved  thereby. 

The  plants  used  in  different  countries  differ  considerably  in 
their  botanical  relationships,  but  the  watery  extracts  from  most 
of  them  now  in  use  have  an  acid  reaction.  There  are  a  few 
which  are  said  to  have  an  alkaline  reaction. 

According  to  Jumelle,  the  natives  in  French  Soudan  use 
four  liquids  for  coagulating  Landolphia  Heudelotii  :  (i)  juice  of 
citron,  made  by  crushing  ten  fruits  in  a  litre  of  water  ;  (2)  water 
acidulated  with  the  fruit  of  Adansonia  digitata,  one  ripe,  macerated 
fruit  being  sufficient  for  one  litre  of  water  ;  (3)  water  acidulated 
by  the  leaves  or  calyces  of  the  Rozelle  plant — Hibiscus  Sabbariffa, 
500  grams  of  leaves  and  fruits  being  used  in  one  litre  of  water  ; 
(4)  infusion  of  fruits  of  Tamarindus  indica,  2  handfuls  of  fruits 
being  required  for  one  litre  of  water.  All  these  plants  are  abund- 
antly distributed  and  cultivated  in  many  parts  of  the  tropics 
and  can  easily  be  tried  by  planters.  In  Ecuador  and  the  Belgian 
Congo,  the  juice  from  the  stalks  of  ' '  bossanga" — Costus  Lukanus- 
ianus — is  largely  used  as  a  coagulant.  The  watery  extract  from 
the  macerated  stalks  of  Calonyction  speciosum — which,  according 
to  Preuss,  is  alkaline  in  reaction — is  also  used  in  Ecuador  and 
Central  America  generally.  Another  plant  which  has  received 
considerable  attention  as  a  source  of  an  effective  coagulant  is 
Bauhinia  reticulata,  a  species  now  established  in  most  of  the 
botanic  gardens  throughout  the  tropical  world.  It  is  largely  used 
in  the  production  of  rubber  from  the  latex  of  Funtumia  elastica. 


PARA     RUBBER  327 

According  to  Mountmorres  a  handful  of  the  green  leaves  and 
young  shoots  is  placed  in  two  gallons  of  water,  and  boiled  for 
about  fifteen  minutes,  the  filtered  infusion  being  poured,  while 
hot,  into  about  one-and-a-half  gallons  of  fresh  latex. 

It  is  obvious  that  aqueous  extracts  of  parts  of  plants  such 
as  those  mentioned  above  may  contain  a  number  of  useless  as 
well  as  useful  ingredients.  It  is  therefore  difficult  to  ascribe 
the  good  physical  properties  of  the  coagulated  rubber  to  any 
definite  substance  or  substances  until  these  have  been  chemically 
investigated.  The  plants  used  for  this  purpose  are  among  those 
most  commonly  met  with  in  tropical  areas,  and  the  subject  is 
therefore  one  which  should  arrest  the  attention  of  all  rubber 
planters. 

Smoking  and  Coagulation. 

The  coagulation  of  the  latex  may  be  hastened  by  exposing  it  to 
heat  and  the  products  of  combustion  of  a  fire.  The  latex  can  be 
coagulated  fractionally  by  such  a  process,  and  the  finished  product, 
when  properly  manufactured,  is  less  liable  to  putrefaction  than  the 
rubber  prepared  by  many  other  methods.  The  smoke  from 
burning  palm  nuts  used  in  the  Amazon  district  contains,  among 
other  substances,  small  quantities  of  acetic  acid,  acetone,  and 
creosote.  The  acetic  acid  is  probably  the  agent  responsible  for 
effecting  coagulation  ;  the  other  substances,  particularly  the 
creosote,  are  abs'orbed,  the  latter  acting  as  an  antiseptic  in  pre- 
venting the  rapid  decomposition  of  the  albuminoids  present. 

Coagulation  by  Chemical  Re-agents. 

In  coagulation  by  chemical  means  the  object  is  to  use  re-agents 
which,  while  effectively  and  rapidly  precipitating  the  coagulable 
material,  will  not  have  a  detrimental  effect  on  the  rubber  pro- 
duced. 

Many  compounds,  such  as  picric  acid,  would  rapidly  induce 
coagulation,  but  the  effect  on  the  resulting  rubber  would  be  bad. 
Weber  and  Parkin  have  shown  that  many  acids  may  be  used  in  the 
coagulating  process,  but  it  is  unnecessary  to  do  more  than  mention 
those  which  have,  from  practical  experience,  been  proved  more  or 
less  acceptable  to  planters. 

Acetic  acid. — This  is  cheap,  always  procurable,  is  not  danger- 
ous to  handle,  and  is  as  effective  as  formic  acid.  It  is  not  as 
powerful  as  tannic  acid,  though  it  is  effective  in  bringing  about 
coagulation  of  the  latex  while  cold.  The  commercial  article 
varies  in  strength  and  the  quality  should  be  noted  by  the  pur- 
chaser. The  rubber  produced  by  means  of  this  coagulant  is, 
according  to  Henri,  of  inferior  quality. 

Formic  acid. — This,  though  similar  to  acetic  acid  in  its  effect,  is 
more  expensive,  weight  for  weight.  The  advantages  of  using  this 
re-agent  are  (i)  that  less  is  required  than  of  acetic  acid,  and  (2)  it  has 
antiseptic  properties.  Whether  acetic  .or  formic  acid  is  used,  it 
should  be  applied  in  definite  proportions,  and  no  more  need  be  used 
than  is  required  just  to  precipitate  the  albumen  in  the  latex. 


328  PARA     RUBBER 

Formic  acid  is  less  pleasant  to  handle  than  acetic.  Spence  (I.R.J., 
April,  1908),  has  experimented  with  formic  acid,  which  he  prefers 
to  acetic.  The  rubber  obtained  was  of  good  quality  and  was 
pale  yellow  in  colour  ;  an  acetic  acid  prepared  specimen  from  the 
same  latex  was  dark-brown. 

Tannic  acid. — This  is,  according  to  Weber,  the  most  powerful 
of  the  acids  which  can  be  used  for  this  process  ;  he  asserts  that  on  a 
laboratory  scale  it  is  excellent  for  use  with  the  latex  of  Para  rubber. 
If  rubber  coagulated  by  tannic  acid,  while  still  wet,  be  placed  in  an 
incubator  at  temperatures  from  100°  F.  upwards,  it  rapidly  passes 
into  a  state  of  putrescid  fermentation,  but  such  a  change  does  not 
occur  if  the  rubber  is  thoroughly  dry. 

Mercuric  chloride. — Corrosive  sublimate  effects  coagulation 
while  the  latex  is  cold,  and  also  acts  as  an  antiseptic.  It  is  very 
poisonous,  and  if  used,  a  small  quantity  of  the  salt  is  unavoidably 
left  in  the  rubber.  Rubber  prepared  in  this  way  can  perhaps  be 
put  on  the  market,  if  it  is  made  perfectly  clear  to  the  buyers 
how  it  has  been  prepared.  Though  such  rubber  appears  to  be  of 
good  quality,  some  further  tests  are  necessary  before  any  definite 
recommendation  can  be  made. 

Carbonic  acid  gas. — The  use  of  this  gas  is  proposed,  and  a 
patent  method  of  employing  it — Pahl's — is  now  on  the  market,  but 
not  sufficient  information  is  at  hand  of  its  behaviour  or  of  the  quality 
of  the  rubber  obtained. 

Mixtures. 

The  following  mixtures  produced  samples  of  rubber  of  excellent 
quality  at  the  Ceylon  Rubber  Exhibition  in  1906  ; — A.  i  dram  of 
cream  of  tartar,  dissolved  in  i  oz.  cold  water,  added  to  a  panful  of 
latex  of  about  48  oz.  B.  J  dram  cream  of  tartar,  dissolved  in  4  oz. 
of  fresh  rubber  whey  added  to  a  panful  of  latex  of  about  48  oz. 
Mr.  J.  A.  Bird  is  said  to  have  originated  the  mixtures. 

The  following  is  the  formula  of  a  coagulating  mixture  that  has 
been  devised  by  Morisse  : — 

Solution  A. — Carbolic  acid,  commercial,  4  grammes  ;  alcohol 
in  sufficient  quantity  to  dissolve  it ;   water,  80  grammes. 

Solution  B. — Sulphuric  acid,  commercial,  2  grammes  ;  water, 
20  grammes. 

When  mixed,  these  quantities  are  sufficient  to  coagulate 
instantaneously,  with  the  aid  of  a  little  agitation,  a  litre  (if  pints) 
of  latex.  Morisse  points  out  that  to  coagulate  1,000  litres  of  latex, 
it  takes  2  litres  of  sulphuric  acid  and  4  of  carbolic,  which  in  his 
opinion  makes  the  method  a  very  inexpensive  one.  Some  rubber 
prepared  in  this  way,  exposed  to  the  air,  hght,  and  dust  during 
twelve  years,  was  as  good  in  July,  igoi,  as  it  was  when  prepared 
in  February,  1888.  Under  the  influence  of  a  little  free  sulphur  in 
the  coagulating  solution,  it  had  become  veritably  vulcanised.  In 
March,  1908,  this  sample  was  in  the  same  perfect  condition.  In 
this  connection  we  may  recall  the  fact  that  Spence  found  rubber 
coagulated  with  sulphuric  acid  to  deteriorate,  though  it  must  be 
noted  that  he  did  not  add  an  antiseptic. 


PARA     RUBBER  329 

Proprietary  Coagulants. 

There  are  a  number  of  patent  or  otherwise  secret  compositions 
on  the  market,  but  one  cannot  learn  of  the  extent  to  which 
all  are  used.  Hydrofluoric  acid  is  sold  under  the  name  of 
"Purub,"  and  under  that  of  "Coagjline"  is  retailed  a 
mixture  of  the  following  composition  :  tartar  emetic,  3  per 
cent.  ;  formaldehyde,  0-5  per  cent.  ;  carbolic  acid,  0-5  per 
cent.  ;  and  water,  96  per  cent.  We  have  also  the  Elias  process, 
the  Pinto  process,  and  that  of  Dern,  among  others. 

Amount   of   Acetic   Acid   to   be   used. 

The  quantity  of  acid  required  is  believed  to  largely  depend 
upon  the  proportion  and  condition  of  the  albumen  in  the  latex. 
According  to  Weber,  the  latex  from  Hevea  trees  in  the  Amazon 
contains  only  about  1-5  per  cent,  of  albumen,  and  one-third  of  an 
ounce  of  anhydrous  formic  or  half-an-ounce  of  glacial  acetic  acid  per 
gallon  of  the  latex  is  quite  sufficient  to  produce  rapid  and  complete 
coagulation.  The  behaviour  of  the  latex  with  acids  is  due  to  the 
fact  that  it  is,  when  fresh,  usually  slightly  alkaline  or  neutral,  and 
the  protein  substances  are  insoluble  in  a  feebly  acid  solution  but 
soluble  in  alkaline  or  strongly  acid  solutions.  It  has  been  asserted  ■ 
that  the  protein  matter  is  insoluble  in  a  neutral  solution,  but 
on  several  occasions  the  fresh  latex  from  the  Henaratgoda  trees 
remained  liquid,  though  the  reaction  with  litmus  paper  did  not 
indicate  acidity  or  alkalinity.  Only  a  small  quantity  of  acid  is 
required  to  neutralize  or  acidify  the  latex,  and  therefore  lead  to 
coagulation.  It  is  a  mistake  to  add  excess  of  acetic  acid,  as  the 
proteins  or  their  derivatives  would  be  partly  re-dissolved  and 
would,  therefore,  still  remain  in  solution.  Instead  of  protein 
being  the  agent  in  coagulation,  an  idea  held,  as  already 
mentioned,  is  that  latex  behaves  as  an  emulsion  in  the  presence 
of  an  acid. 

Quantity  of  Acetic  Acid  used  on  Estates. 

In  the  last  edition  the  following  remarks  were  made  : — 
"Every  100  volumes  of  pure  Ceylon  latex  require  about  one 
volume  of  pure  acetic  acid.  Many  planters  add  one  or  two  drops 
of  acetic  acid  to  about  half- a- gallon  of  the  diluted  latex.  On 
Culloden  estate  three  drams  of  acetic  acid  are  added  to  each 
gallon  of  latex,  no  matter  in  what  condition  the  latter  arrives  at 
the  factory  ;  the  acetic  acid  consists  of  three  parts  water  and  one 
part  glacial  acetic.  On  Gikiyanakanda  one  dram  of  acetic  acid 
is  used  for  each  gallon  of  latex.  If  the  acetic  acid  is  added  until 
the  mixture  becomes  feebly  acid  after  stirring  very  little 
harm  will  be  done.  The  addition  of  excess  of  acid  may  bring 
about  a  re-solution  of  the  proteins  and  coagulation  be  thereby 
delayed.  It  is  very  rare  that  the  latex  on  a  large  scale  is  heated 
before  treatment  with  acetic  acid." 

On  Glenealy  estate  one  fluid  drachm  of  a  10  per  cent,  solution 
is  added  to  each  quart  of  latex ;  that  is,  one  part  of  pure  acetic 
<;oagulates  3,226  parts  of  latex.  Coagulation  takes  place  in  two 
hours. 


330  PARA     RUBBER 

A  Recent  Research  ;    Quantity  of  Acid. 

The  above  differences  in  the  quantities  of  acid  employed 
have  been  commented  upon  by  Crossley  (I.R.J.,  27th  May,  1911). 
The  first-mentioned  quantity  being  100  volumes  of  latex  to  i  of 
acid,  he  points  out  that  on  CuUoden  1,706  volumes  of  latex  are 
coagulated  and  on  the  Gikiyanakanda  1,280  volumes,  while  Weber's 
estimate  equals  320  volumes.  He  suggests  that  these  differences 
are  explicable  by  different  degrees  of  dilution  and  by  variations  in 
the  amount  of  fermentation  acid  already  present.  Working  with  a 
Sumatran  latex  to  which  formalin  had  been  added,  and  which 
probably  had  been  diluted  with  water  three  or  four  times,  he 
determined  the  limits  in  quantity  of  acid  that  could  be  used.  In 
the  case  of  this  particular  latex  the  minimum  proportion  of  pure 
glacial  acetic  acid  producing  efficient  coagulation  was  one  part 
by  weight  of  acid  to  1,176  parts  by  volume  of  latex.  But  the 
fermentation  acids  were  already  present,  and  played  some  part 
in  coagulation.  Allowing  for  these,  and  assuming  that  their 
coagulating  power  in  the  aggregate  was  equal  to  that  of  the  same 
quantity  of  acetic  acid,  the  true  coagulating  power  of  the  total 
acid  present — fermentation  plus  added  acid — was  one  part  by 
weight  of  acid  to  575  parts  by  volume  of  latex  neutral  in  reaction.  In 
view  of  Parkin's  declaration  that  ' '  the  percentage  of  acid  necessary 
is  proportional  only  to  the  original  volume  of  latex  present,  and  is 
independent  of  its  dilution  with  water, ' '  Crossley  made  a  series 
of  experiments  with  the  latex  diluted  in  different  degrees,  when 
he  found  that  the  statement  held  good  over  a  long  range  of  values, 
After  plotting  out  the  results  in  the  form  of  a  curve,  he  computed 
that  a  minimum  of  07  c.c.  of  pure  glacial  acetic  acid  would  be 
necessary  to  coagulate  100  c.c.  of  pure  fresh  latex.  Determinations 
were  made  to  show  what  was  the  maximum  quantity  of  acid  that 
could  be  used  to  produce  coagulation  in  the  above  sample  of  latex  ; 
as  far  as  these  experiments  went,  they  proved  that,  ignoring 
the  fermentation  acid  present,  it  was  20-4  times  the  minimum. 
Taking  the  fermentation  acid  into  account,  that  is,  basing  the 
calculation  upon  the  total  acidity  of  the  latex,  it  was  10-4  times 
the  minimum.  The  relation  between  the  minimum  and  maximum 
quantities  of  acid  varies  with  the  dilution  ;  the  ' '  factor  of  safety, ' ' 
or  difference  between  them,  must  be  much  less  in  the  case  of 
undiluted  latex  than  it  was  in  the  latex  experimented  upon. 

Time    Required    for   Coagulation. 

The  completeness  of  coagulation  is  judged  by  the  clearness 
or  turbidity  of  the  liquid  in  which  the  rubber  floats.  When  the 
separation  of  caoutchouc  is  complete,  the  mother  Hquor  is  quite 
clear  ;  where  special  machines  are  used  the  latex  is  coagulated  in 
three  to  ten  minutes.  On  Culloden  estate,  without  the  use  of  any 
apparatus,  the  latex  is  completely  coagulated  in  ten  minutes  ;  on 
Vogan  in  a  couple  of  hours  ;  and  on  another  estate  in  the  same 
district  half-an-hour  was  generally  allowed  for  complete  coagulation. 


PARA     RUBBER  331 

Advantage   of  Rapid  Coagulation. 

The  variation  in  time  allowed  for  coagulation  is  still  con- 
siderable, though  the  opinion  is  gaining  ground  that  the  more 
rapidly  the  latex  can  be  coagulated,  the  more  satisfactory  are  the 
results.  It  is  maintained  by  some  planters  that  the  more  quickly 
the  latex  is  coagulated  and  put  through  the  washing  rollers,  the 
more  rapidly  the  rubber  dries,  a  point  of  practical  importance, 
especially  where  hot  air  is  not  used  in  the  drjdng  sheds.  Further- 
more, when  latex  has  to  be  collected  over  widely-scattered  acre- 
ages, some  time  often  elapses  before  it  can  be  delivered,  as  such, 
at  the  factory.  Under  such  circumstances  it  appears  advisable 
to  effect  coagulation  in  the  field,  providing  the  process  can  be 
carried  out  in  a  proper  manner  in  the  absence  of  the  usual  super- 
vision. 

Methods  of    Determining  the   Quantity   of   Acetic 
Acid    Required. 

It  has  been  contended  that  many  inventions  which  have 
recently  been  brought  forward  necessitate  dilution,  to  varying 
degrees,  with  water,  ammonia,  and  formalin,  and  that  such 
dilution  prevents  the  planter  from  knowing  how  much  latex  the 
coolies  collect,  and  how  much  acetic  acid  will  be  required  in  the 
process  of  coagulation.  It  is  quite  true  that  the  latex  so  treated 
will  contain  varying  quantities  of  rubber,  but  when  one  considers 
the  variation  in  composition  of  ordinary  samples  of  undiluted  latex 
from  different  trees,  or  when  obtained  at  different  times  of  the 
year  from  the  same  trees,  it  is  obvious  that  the  same  difficulty 
has  ordinarily  to  be  overcome.  The  objection  is,  therefore,  not  a 
very  serious  one  so  long  as  latex  is  not  sold  by  volume. 

The  application  of  the  same  quantity  of  acetic  acid  to  the 
same  volume  of  latex  on  every  occasion  cannot  be  recommended 
except  for  expediency.  The  acid  should  be  added  in  order  to 
neutralize  or  faintly  acidify  the  latex  ;  it  is  better  to  determine 
the  exact  quantity  required  than  to  add  too  much. 

The  amount  of  acid  required  can  be  determined  with  ease.  Let 
the  coolies  pour  the  diluted  latex  from  the  different  trees  into  a 
settling  tank  or  ordinary  receptacle  and  fill  up  to  a  known  level,  so 
that  the  exact  volume  will  be  known.  After  thoroughly  stirring 
the  mixture  take  a  small  sample  of  known  volume  and  add  dilute 
acetic  acid  of  constant  strength,  drop  by  drop,  from  a  burette  or 
graduated  glass  tube,  until  the  whole  mixture  after  stirring  is 
neutral  or  faintly  acid.  On  measuring  the  volume  of  acetic  acid 
used,  the  amount  required  for  complete  coagulation  of  the  latex  in 
the  settling  tank  can  be  easily  calculated  and  added.  Litmus  paper 
can  be  used  to  determine  when  sufficient  acetic  acid  has  been  used  ; 
the  resultant  solution  should  be  only  faintly  acid  or  neutral,  blue 
litmus  paper  becoming  faintly  red  and  red  litmus  paper  remaining 
unchanged  respectively  in  such  solutions. 

Such  a  method  may  involve  the  accumulation  of  the  latex  in 
receptacles   of   known   capacity   and   provided   with   mechanical 


332  PARA     RUBBER 

means  for  keeping  the  latex  in  a  liquid  state.  Some  such  apparatus 
may  or  may  not  be  required  as  the  trees  on  the  various  rubber 
estates  are  more  frequently  tapped. 

On  this  subject  Parkin  (I.R.J.,  1911),  remarks  :—"  It  seems 
to  me  that  the  proper  way  to  control  the  coagulation  would  be  to 
test  first  a  small  quantity  of  the  large  volume  of  diluted  latex 
awaiting  treatment.  This  could  be  so  arranged  as  to  occupy  only 
a  few  minutes.  A  spirit  lamp,  a  few  test  tubes,  and  one  or  two 
other  simple  chemical  devices  are  all  that  would  be  required. 
Heating  brings  about  the  coagulation  much  more  rapidly,  hence 
the  value  of  the  spirit  lamp  or  some  similar  contrivance.  The 
quantity  of  acid  required  is  the  same  in  either  heat  or  cold.  A 
simple  calculation  from  this  preliminary  test  will  give  the  amount 
of  acid  to  be  added  to  the  large  bulk  of  dilute  latex,  the  volume 
of  which  has  been  previously  measured. 

"  The  supervisor  of  this  part  of  the  proceedings  in  the  factory 
would  soon  have  a  good  idea  of  the  quantity  of  acid  needed,  so 
that  the  test  for  each  lot  of  latex  would  be  carried  out  very  quickly 
as  a  rule,  serving  more  as  a  precaution  or  check  than  anything  else. 
The  strength  of  the  acetic  acid  employed  must  also  be  known,  as 
I  imagine  that  pure  (glacial)  acetic  acid  will  be  rarely  used  on  the 
estates. 

On  theoretical  grounds  Schidrowitz  doubts  very  much  Parkin's 
assertion  that  the  quantity  of  acid  required  is  the  same  in  heat 
or  cold. 

The  suggestion  made  by  Dr.  Schidrowitz  for  fixing  the  amount 
of  acid  required  is  as  follows  :  ' '  On  the  whole,  I  think  that  the 
best  method  of  estimating  the  quantity  of  acid  to  be  added  would 
be  that  of  adding  varying  quantities  of  acid  to  a  number  of  samples 
of  bulked  latex  and  noting  the  minimum  quantity  which  gives 
a  good  result,  and  also  the  dry  weight  of  rubber  obtained  in  each 
case.  This  should  be  repeated  say  once  a  week,  and  gradually  in 
this  way  the  plantation  manager  would  accumulate  statistical 
material  which  would  enable  him  to  judge  with  comparative 
ease  how  any  particular  batch  of  latex  (according  to  rubber 
content,  time  of  year,  plot  from  which  derived)  should  be  handled. 
As  an  additional  safeguard,  the  litmus  test  could  be  used  con- 
stantly as  a  rough  check. ' ' 

Advantages  and  Disadvantages  of  adding  Chemicals  to  the 

Latex. 

It  has  been  frequently  contended  that  manufacturers  object 
to  the  use  of  chemicals  in  coagulation,  particularly  mineral  and 
vegetable  acids,  on  account  of  the  fact  that  even  after  thorough 
washing  and  pressing  some  of  the  acid  may  still  remain  in  the 
rubber  and  subsequently  prove  harmful  in  the  manufacturing 
processes.  The  retention  of  a  large  proportion  of  foreign  chemical 
ingredients  is  said  to  lead  to  the  production  of  bubbles  and  blow 
holes  and  to  be  occasionally  accompanied  by  early  deterioration 
of  the  prepared  rubber. 


PARA     RUBBER  33S 

On  the  other  hand,  it  can  be  shown  that  the  addition  of 
re-agents  such  as  formaUn,  creosote,  or  acids  such  as  formic  and 
even  hydrofluoric,  have  a  preservative  effect  on  the  rubber  when 
used  in  infinitely  small  quantities.  When  one  considers  the 
chemicals  which  are  incorporated  in  rubber  of  good  repute  prepared 
by  the  natives  in  the  Amazon  district  and  the  inert  characteristic  of 
rubber  itself,  the  objection  to  the  use  of  minimum  quantities  of 
re-agents  such  as  acetic  acid  and  creosote  seems  to  be  less  tenable. 
But  apart  from  the  preservative  action  of  some  of  the  chemicals 
used,  there  is  a  much  more  serious  advantage,  to  the  producer, 
accompanying  the  use  of  the  required  quantity  of  acetic  acid,  viz., 
the  rapidity  and  completeness  of  the  coagulation  effected. 

Why  Acids  Should  be  Used. 

In  one  experiment  about  i|  gallons  of  ordinary  latex  were 
poured  into  a  large  glass  beaker  and  allowed  to  coagulate  naturally. 
At  the  end  of  two  days  a  large  cake  of  rubber  had  formed  at  the  top 
of  the  liquid,  but  the  mother  liquor  was  still  quite  milky ;  the  cake  of 
rubber  was  removed,  and  subsequently  thinner  cakes  appeared  at 
the  surface  and  were  removed  ;  after  six  days  the  mother  liquor 
still  remained  turbid,  and  a  further  quantity  of  rubber  was  pre- 
pared from  it  by  treatment  with  a  small  quantity  of  acetic  acid 
and  heating.  The  completeness  of  coagulation,  when  the  latex  is 
allowed  to  set  untreated  with  acids,  does  not  always  take  such 
a  long  time,  but  it  is  probable  that  the  same  phenomenon  may 
repeat  itself,  and  thus  necessitate  considerable  delay  and  perhaps 
waste  ;  certainly  it  would  involve  considerable  irregularity  to  the 
producer.  The  use  of  acetic  acid,  on  the  other  hand,  effects 
coagulation  in  a  few  hours,  and  the  mother  liquor  becomes  per- 
fectly clear  in  less  than  a  day  ;  the  precipitation  is  complete,  and 
there  is  therefore  no  waste  of  rubber. 

If  the  planter  is  compelled  to  stop  using  acetic  or  any  other 
acid  for  assisting  coagulation,  and  has  to  produce  his  rubber  by 
simply  allowing  the  latex  to  slowly  ferment,  there  are  other 
difficulties  in  the  way.  It  is  obviously  to  the  advantage  of  the 
producer  to  reduce  the  proportion  of  scrap  in  his  rubber  and  to 
keep  the  latex  flowing  as  long  as  possible,  and  the  use  of  ammonia 
and  formalin  to  accomplish  this  is  being  adopted  on  many  estates 
during  tapping  operations ;  the  presence  of  these  re-agents  in  the- 
latex  tends  to  prevent  coagulation,  and  they  would,  therefore, 
further  aggravate  the  question  of  delay  necessary  if  the  natural 
process  of  coagulation  were  compulsory ;  a  long  period  of  time 
would  be  required  for  the  necessary  acidity  to  develop  in  presence 
of  either  of  these  re-agents. 

In  the  absence  of  definite  information  from  manufacturers, 
the  use  of  minimum  quantities  of  acetic  acid,  determined  by  the 
simple  methods  previously  described,  is  likely  to  be  continued 
by  the  producer  ia  the  tropics.  For  the  present  the  application 
of  the  correct  quantity  of  acid,  followed  by  thoroughly  washing 
and  rolling,  may  be  adopted,  but  care  must  be  exercised  not  to  add 


334  PARA     RUBBER 

excess,  and  every  effort  be  made  to  subsequently  expel  the  re-agent 
by  suitable  mechanical  processes.  One  of  the  most  marked 
examples  that  has  been  recorded  of  the  evil  effects  of  excess  of 
acid  was  a  sheet  of  rubber,  quarter  of  an  inch  or  more  thick, 
that,  as  a  result  of  over-dosing  with  acetic,  was  perfectly  rotten 
and  could  be  torn  like  cardboard. 

Effect  of  Acid  on  Quantity  of  Protein  in  Rubber. 

In  order  to  determine  if  the  quantity  of  protein  in  the  rubber 
was  affected  by  the  quantity  of  acid  used,  Crossley  (I.R.J.,  27th 
May,  1 911),  made  a  series  of  determinations,  using  an  acetic 
acid  solution  containing  0-0543  grammes  of  acid  in  each  cubic 
centimetre 


Percentage    acidity   of 

Acid  used  for 

Protein  found 

medium  in  which 

2oc,c  of  latex. 

in  Rubber. 

coagulation  took 
place. 

0-36  c.c. 

3-19% 

0-184% 

o-6o  c.c. 

3-20% 

0-245% 

090  c.c. 

3-49% 

0-320% 

I-20  c.c. 

3-92% 

0-392% 

6'oo  c.c. 

3-99% 

1-322% 

The  series  shows  that  it  is  an  advantage 

to  add  the  minimum 

quantity  of  acid. 

Receptacles  for  Coagulating  the  Latex  in   Bulk. 

Having  shown  that  many  different  processes  are  in  vogue  in 
various  parts  of  the  world,  and  that  on  plantations  the  use  of 
acetic  or  other  acids  is  desirable,  the  next  step  is  to  determine  the 
most  suitable  receptacles  wherein  the  latex  can  be  kept  during 
coagulation.  If  ammonia  is  used  in  the  latex,  copper  receptacles 
cannot  be  used.  The  best  materials  are  glazed  earthenware  or 
enamelled  troughs.  If  these  are  shaped  similarly  to  a  bath  and 
are  provided  with  an  outlet  pipe  at  the  bottom  for  running  off  the 
mother  liquor,  they  should  itieet  the  requirements.  It  is  necessary 
that  the  receptacles  be  made  of  material  which  can  be  kept  clean 
and  which  will  not  rust.  It  is,  furthermore,  advisable  to  supply 
a  sieved  funnel,  through  which  the  latex  can  be  poured  and  filtered, 
at  one  end  of  the  receptacle.  A  lid  should  also  be  provided  to 
keep  out  dust.  The  size  depends  upon  the  quantity  of  latex 
daily  harvested  ;  the  number  is  dependent  upon  the  same  factor, 
and  whether  the  latex  from  fields  of  different-aged  trees  is  kept 
separate  or  not. 

In  cases  of  emergency,  planters  use  empty  kerosine  oil  tins  or 
wood  barrels.  The  former  are,  however,  liable  to  rust,  and  the 
latter  to  hide  and  encourage  the  accumulation  of  mechanical 
impurities  ;  both  should  therefore  only  be  regarded  as  temporary 
expedients.  The  above  are  for  latex  when  crepe  is  the  form  of 
preparation  intended.  When  sheet  or  biscuits  are  made,  enamelled 
trays,  rectangular  or  circular,  are  used.  The  trays  vary  in  depth 
from  if  to  4  inches.     The  rectangular  trays  are  in  various  sizes, 


CROSSING     PLATE. 


Li'iil  hii  Mniiornil  Port.  nail.  Coy. 
A     MONORAIL     IN     USE. 


PARA     RUBBER  335 

1.2  by  8, 16  by  10,  6  by  18,  10  by  18  and  9  by  18  inches  ;  the  circular 
trays  are  usually  from  gj  to  12  inches  in  diameter. 

Rapid  Coagulation  by  Mechanical  and  Electrical  Means. 

It  may  appear  to  be  quite  unnecessary  and  perhaps  inadvisable 
to  unduly  hasten  coagulation,  seeing  that,  by  the  use.  of  acetic 
acid  in  specified  quantities,  this  work  can  be  effectively  carried 
out,  in  bulk,  in  less  than  an  hour.  It  may,  however,  be  possible 
to  effect  coalescence  of  the  caoutchouc  globules  without  the  use  of 
acids  or  other  chemical  re-agents,  though  all  the  inventions  so  far 
on  the  market,  with  one  or  two  exceptions,  appea.r  to  be  dependent 
upon  the  use  of  re-agents  at  some  stage  of  the  process.  Several 
mechanical,  electrical  and  mechanical-chemical  inventions  have 
been  placed  on  the  market. 

French    Spray    Patent. 

In  this  process  (Journ.  Soc.  Chem.  Ind.,  Vol.  xxx.,  No.  19), 
invented  by  Hamet  and  Mounier,  the  latex  is  forced  from  a  vessel' 
by  means  of  a  pump,  through  a  tube,  ending  in  an  atomising-jet 
within  the  domed  lid  of  a  coagulating  chamber  ;  simultaneously 
a  jet  of  steam,  hot  water,  or  acid  or  formaldehyde  solution, 
delivered  from  a  second  vessel,  and  similarly  atomized,  is  caused 
to  impinge  upon  the  latex-spray.  The  coagulating  vessel  is 
provided  with  a  perforated  false  bottom,  by  means  of  which  the 
coagulated  rubber  is  strained  off  from  the  mother  liquor  and 
added  liquid,  and'  upon  which  the  rubber  can  if  necessary  be 
washed  before  being  removed,  pressed  and  dried.  The  coagulating 
chamber  has  an  uptake  for  the  escape  of  vapours. 

Biffen's  Centrifugal  Machine. 

Biffen  recognised  that  in  latex  the  indiarubber  existed  as 
suspended  globules,  lighter  than  water,  and  employed  for  separating 
the  caoutchouc,  a  centrifugal  machine  similar  to  that  used  in 
separating  butter  from  milk.  The  machine  was  a  modified  form 
of  the  ordinary  centrifugal  milk  tester  capable  of  being  rotated 
6,000  times  per  minute.  The  caoutchouc  of  Hevea  latex  is  said  to 
be  effectively  separated  in  a  few  minutes  and  to  consist  of  the  pure 
article,  free  from  mixtures  of  proteins,  resins,  etc.  Weber  strongly 
recommended  such  a  process  of  treating  the  latex  for  eliminating 
protein  constituents. 

Biffen  claims  that  the  rubber  may  thus  be  prepared  by  purely 
physical  means  ;  the  light  rubber  globules  are  thrown  out  of  the 
bowl  in  an  almost  dry  state,  and  the  rubber  is  free  from  any 
obnoxious  smell  and  danger  of  decomposition.  It  is,  however, 
questionable  whether  pure  caoutchouc  free  from  resinous  and 
other  impurities,  is  desired  by  the  manufacturers.  It  is  certainly 
not  essential  to  remove  all  traces  of  these  substances. 


336  PARA     RUBBER 

Experiments   in   Ceylon. 

Furthermore,  several  small  experiments  carried  out  in  Ceylon 
have  proved  that  the  caoutchouc  in  Hevea  latex  is  not  rapidly 
separated  by  a  centrifugal  machine,  even  when  the  speed  is  as 
high  as  11,000  revolutions  per  minute.  In  these  experiments 
various  heavy  chemicals  were  added  to  the  latex  after  the  formalin  ; 
the  chemicals  used  did  not  show  an  acid  reaction,  and  considerably 
increased  the  density  of  the  alkahne  mother  liquor.  The  whole 
of  this  mixture  was  placed  in  the  ' '  Aktiebolaget  Separator, ' '  and 
then  subjected  to  centrifugal  force  for  over  an  hour,  and  yet  the 
caoutchouc  globules  were  not  effectively  separated  from  the  other 
constituents ;  the  apparatus  was  perhaps  too  small. 

Though  these  experiments  cannot  at  present  be  considered  a 
success,  the  principle  of  increasing  the  density  of  the  mother 
Hquor  by  addition  of  readily  soluble  and  heavy  substances,  and 
then  causing  a  separation  of  the  caoutchouc  globules  by  mechanical 
means,  is  one  which  cannot  be  too  strongly  impressed  on  the 
experimentalist. 

The   Michie     Golledge   Machine. 

Construction. — The  Michie- Golledge  rubber  coagulating 
machine  consists  of  a  revolving  cylinder,  with  angular  ribs  on  its 
inside,  and  curved  blades  which  are  fixtures.  The  latex  is  poured 
into  the  cylinder,  which  is  then  set  in  motion.  The  revolving 
cylinder  and  its  ribs  force  the  latex  forward  on  to  the  blades, 
which  carry  it  into  the  centre  of  the  cyhnder,  creating  a  kind  of 
vortex  or  whirlpool,  and  depositing  the  rubber  in  the  central 
space  in  the  form  of  a  sponge-like  mass.  \\'hen  the  mass  of  rubber 
reaches  the  right  consistency,  it  is  removed  by  hand,  separated 
into  lumps  of  the  required  size,  and  rolled  out  while  it  is  still  soft 
into  sheets  in  a  small  rolling  machine. 

Method  of  Using. — The  latex  is  diluted,  often  as  much  as  400 
per  cent.,  and  after  being  strained  to  remove  the  mechanical 
impurities  and  treated  with  acetic  acid  in  the  proportion  of  i  dram 
of  acetic  to  i  gallon  of  the  diluted  latex,  is  placed  in  the  churn-like 
cylinder.  The  cylinder  is  then  rotated  horizontally  at  the  rate  of 
about  180  revolutions  per  minute  for  about  i-|  minutes,  after 
which  the  speed  is  reduced  to  about  100  revolutions  per  minute  for 
the  next  3J  minutes.  The  coagulated  latex  accumulates  in  the 
centre,  and  the  watery  portion  remains  in  the  outer  part  between 
the  vertical  plates  and  the  wall  of  the  cylinder.  When  the  watery 
portion  is  clear  the  separation  of  the  rubber  is  considered  to  be 
complete,  and  the  coagulated  late.x  is  removed.  The  freshly- 
coagulated  mass  is,  in  the  fresh  state,  very  spongy,  and  is  torn 
into  irregular  pieces  which  are  pressed  between  the  rollers  of  a 
mangle  ;  the  irregular  cakes,  obtained  by  passing  the  spongy  mass 
through  the  rollers,  are  then  cut  into  worm-like  threads  by  means 
of  shears  worked  by  hand  ;  the  ' '  worms ' '  are  next  placed  on 
wooden  shelves  to  dry.  The  rubber  so  prepared  may  at  first 
contain  most  of  the  ingredients  present  in  the  latex,  the  soluble 


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MICHIE-GOLLEDGE  COAGULATOR. 


PARA     RUBBER  337 

portion  of  which  may  be  partially  removed  by  repeatedly  washing 
the  rubber  during  the  rolling  process. 

Mathieu's  Coagulator. 

With  this  apparatus  heat  is  the  coagulant  and  formalin  the 
antiseptic.  The  latex  flows  through  two  adjustable  slits  in  the 
bottom  of  a  receptacle  upon  the  surfaces  of  two  revolving  drums, 
these  surfaces  being  kept  at  a  temperature  of  120°  to  I30°F.  by  a 
hot- water  jacket.  What  makes  the  apparatus  impracticable  is 
the  fact  that,  to  maintain  this  temperature,  hot  water  has  to  be 
introduced  from  time  to  time  into  each  drum.  The  formalin  is 
sprayed  on.  When  the  coatings  of  the  drums  are  one  quarter  of 
an  inch  thick,  they  are  cut  across  and  unrolled  in  sheet  form. 

The  K.L.  Coagulator. 

A  coagulator  invented  by  Mr.  Harvey,  of  Pataling  estate, 
and  known  as  the  "K.L.  Coagulator"  was  exhibited  at  an  ex- 
hibition at  Kuala  Kangsar.  Compared  with  other  inventions, 
this  was  said  to  require  only  a  fraction  of  the  amount  of  coagulant 
■ordinarily  used,  and  to  be  capable  of  turning  out  sponge-rubber, 
ready  for  further  manipulation,  in  from  6  to  10  minutes,  according 
to  the  age  of  the  trees  from  which  the  latex  was  taken. 

Mr.  Harvey,  in  describing  his  machine,  wrote  to  the  Federated 
Engineering  Company,  Limited,  as  follows  : — 

1.  This  machine  occupies  very  little  room,  and  effectively 
does  away  with  the  need  for  coagulating  pans  and  racks,  thus 
saving  space  and  labour. 

2.  Latex  can  be  strained  directly  into  the  machine  im- 
mtediately  it  arrives  from  the  field,  and  a  perfect  coagulation  can 
be  effected  in  five  minutes.     Thorough  bulking  of  latex  is  assured. 

3.  By  the  use  of  this  machine  all  decomposition  of  the 
proteins  contained  in  the  latex  is  rendered  impossible,  and  when 
the  coagulated  rubber  is  washed  through  a  machine,  there  is  an 
entire  absence  of  that  unpleasant  odour  associated  with  new 
rubber  which  has  been  coagulated  naturally  in  pans. 

4.  The  outturn  of  dry  rubber  will  be  found  to  be  more  even 
in  colour. 

5.  The  large  machine  is  capable  of  dealing  with  50  gallons 
of  latex  at  one  time,  while  the  smaller  size  treats  30  gallons. 

6.  It  can  be  worked  easily  by  one  cooly,  and  needs  no 
pulleys  or  belts.     Nor  is  it  necessary  to  set  the  machine  in  concrete. 

7.  The  machine  is  portable,  and  can  be  cleaned  with  ease, 
with  fair  usage  it  is  impossible  to  get  out  of  order  or  broken. 

8.  The  price  is  less  than  one-third  that  of  any  other  coagu- 
lating machine  on  the  market,  and  its  capacity  is  four  times 
greater. 

Instructions  for  Use  with  "K.L.  Coagulator." 

The  following  solution  of  acetic  acid  has  been  found  to  give 
good  results  for  coagulation: — 


338 


PARA     RUBBER 


6  of  water  to  i  of  glacial  acetic,  and 

if  fluid  oz.  of  this  solution  to  every  4  gallons  of  latex. 

Having  strained  the  latex  into  the  coagulator,  turn  the 
handle  slowly  while  pouring  in  the  solution  ;  the  latter  should  be 
poured  in  slowly,  so  as  to  be  as  widely  diffused  as  possible  through- 
out the  latex. 

The  solution  having  all  been  poured  in,  continue  to  turn  for 
about' five  minutes;  a  medium  pace  should  be  maintained  and 
the  handle  occasionally  reversed  for  a  turn  or  two. 

If  there  are  about  35  gallons  of  latex  in  the  coagulator, 
coagulation  starts  in  about  five  minutes,  and  when  once  this  is 
the  case,  it  is  best  to  let  it  stand  and  then  turn  again  in  alternate 
spells  of  short  duration  ;  quantities  of  30  to  50  gallons  of  latex 
may  be  coagulated  in  about  six  to  seven  minutes. 

Smith's  Centrifugal  Machine. 
This  apparatus,  for  which  it  is  claimed  that  Castilloa  latex 
can  be  satisfactorily  treated,  has  been  experimented  with  upon 
Hevea  latex.  The  drum  is  deep,  and  the  sides  are  lined  by  a 
screen  of  cloth  covered  on  both  surfaces  by  layers  of  perforated 
metal.     After  the  apparatus  is  started,  some  water  is  run  into  the 


VERTICAL   SECTION  THROUGH  SMITH'S    MACHINE   AFTER 
SEPARATION    OF  RUBBER. 


drum  and  becomes  spread  over  the  inner  surface  of  the  screen, 
where  it  forms  a  wall  through  which  latex  cannot  escape.  Next, 
the  latex  is  run  in,  and  spreads  itself  in  turn  on  the  inside  of  this 
wall.  After  a  period,  while  the  drum  is  still  revolving,  the  water 
and  the  mother  liquor  which  have  separated  from  the  film  of  rubber 
are  allowed  to  escape  through  holes  in  the  side  of  the  drum.     This 


PARA     RUBBER  339 

allows  the  rubber  to  pass  outwards  and  apply  itself  to  the  inner 
surface  of  the  screen.  Continuation  of  the  motion  removes  some 
water  from  the  rubber,  which  is  finally  removed  in  the  form  of 
sheet  by  slitting  across  the  band  of  rubber  applied  to  the  screens. 
It  is  to  be  noted  that  acetic  acid  has  to  be  added  to  the  latex 
previous  to  treatment.  An  apparatus  has  been  sent  to  Malaya 
for  testing. 

Main's  Centrifugal  Machine. 
The  form  of  this  is  hke  that  of  a  vertical  turbine,  the  blades 
being  supposed  to  direct  the  caoutchouc  globules  inwards,  where 
four  curved  plates,  which  do  not  revolve,  pass  them  on  to  the 
centre.  Here  a  spongy  cylinder  of  rubber  is  formed,  this  rubber 
being  removed  by  hand  as  it  collects.  Again,  acetic  acid  must 
first  be  added. 

Cockerill's  Electrical  Coagulator. 

Cockerill  has  adapted  the  principle  that  caoutchouc  is  de- 
posited from  the  latex  upon  an  electrical  anode.  In  the  earlier 
form  of  his  apparatus  a  continually  moving  anode  is  formed  by  an 
endless  belt  coated  with  graphite.  Above  it,  with  its  free  end 
half-an-inch  from  the  belt,  is  a  metal  cathode.  Latex  running  on 
to  the  belt  has  its  caoutchouc  attracted  by  it,  and  the  residual 
serum  runs  into  drip-pans  below.  The  film  of  rubber  is  scraped 
off  the  belt  and  afterwards  is  run  between  rollers  to  press  out  some, 
of  the  water  remaining.  In  the  later  form,  both  anode  and  cathode 
take  the  shape  of  endless  belts,  one  above  the  other,  built  up  of. 
metallic  sections  hinged  together.  The  lower  belt  composes  the. 
trough  which  carries  the  latex  and  is  made  water-tight,  while 
there  are  provisions  for  keeping  the  latex  from  overflowing  and 
for  preserving  its  contact  with  the  surfaces  of  both  electrodes. 
Means  are  provided  for  the  removal  of  the  serum,  and  for  the 
washing  and  branding  of  the  rubber  sheet. 

Coagulation    in    the    Field    or    Factory. 

On  most  estates  the  latex  is  collected  in  the  field  and  des- 
patched to  the  factory  in  pails  carried  by  hand  or  in  tanks  along 
a  monorail,  where  it  is  almost  immediately  coagulated.  It  is 
obvious,  however,  that  a  large  quantity  of  water  is  thus  trans- 
mitted ;  in  order  to  effect  economy  several  planters  have  suggested 
that  coagulation  should  be  done  in  the  field  and  only  the  freshly- 
coagulated  rubber  need  then  be  carried  to  the  central  factory.  Mr., 
Golledge,  Gikiyanakanda,  informed  me  that  he  proposed  to  erect 
small  sheds  each  equipped  with  a  coagulating  machine  on  every 
hundred  acres  of  land  ;  the  coagulated  rubber  from  each  shed 
could  then  be  carried  to  the  factory  for  final  manipulation. 

Proteins,  etc.,  in  Coagulated  Rubber. 

Whenever  rubber  is  prepared  by  ordinary  coagulation,  either 
by  the  smoking  method  or  the  use  of  familiar  chemical  re-agents,. 


340  PARA     RUBBER 

hot  or  cold,  it  is  obvious  that  the  rubber  must  contain  the  proteins 
together  with  the  suspended  globules  of  caoutchouc,  resin,  &c. 
Analyses  of  well-dried  Para  rubber  show  only  a  small  percentage 
of  substances  other  than  caoutchouc — practically  from  4  to 
6  per  cent. — and  it  may  at  firs  sight  appear  unnecessary  to  draw 
attention  to  the  desirability  of  extracting  them.  If  one  compares 
the  analyses  of  latex  and  rubber  from  Hevea  brasiliensis,  it  is 
surprising  to  find  that  when  chemical  re-agents  have  been  used 
the  percentage  of  protein  matter  in  the  rubber  shows  that  the  whole 
of  that  in  the  latex  was  not  precipitated,  and  Bamber  and  Parkin 
proved  that  the  clear  liquid  remaining  after  coagulation  with  acetic 
acid  often  gave  re-actions  with  the  tests  for  proteins.  The  amount 
of  protein  in  the  clear  hquor  may,  according  to  Bamber,  be  as  much 
as  50  per  cent,  of  the  original.  It  may  be  asserted  that  a  great  part 
of  these  substances  generally  occurs  in  the  prepared  rubber,  and 
their  presence  along  with  other  substances  leads  in  many  cases  to 
putrefaction. 

Use  of  Antiseptics. 

If  the  local  conditions  are  such  that  the  rubber  cannot  be 
prepared  by  any  method  other  than  coagulation,  and  the  protein 
and  other  materials  must  be  included,  it  will  be  necessary  to  take 
steps  to  keep  the  obnoxious  ingredients  in  a  quiescent  state. 
This  can  be  done  by  treating  the  latex  with  some  re-agent  which 
has  antiseptic  properties,  such  as  creosote  or  corrosive  subUmate, 
and  quickly  drying  the  rubber  after  effectively  washing  and 
pressing  the  freshly-coagulated  material.  It  must  be  recalled 
that  the  acetic  acid  method,  as  first  devised  by  Parkin,  included 
the  use  of  creosote. 

Creosote  is  a  mixture  of  many  substances,  some  of  which  are 
slightly  soluble  in  water,  others  entirely  insoluble.  Of  those  that 
are  slightly  soluble  are  such  antiseptic  agents  as  carboUc  acid  and 
cresols,  one  of  the  latter  having  been  tried  alone,  with  what  result 
has  not  yet  been  made  public.  Parkin  recommends  the  use  of  a 
weak  aquequs  emulsion,  added  to  the  latex  before,  or  preferably 
with,  the  acetic  acid. 

At  the  Ongyem  station,  in  Cochin  China,  i  c  .c.  of  formalin  is 
added  with  the  coagulant  to  every  1,000  c.c.  of  latex,  which  is 
diluted.  After  the  last  passage  of  the  rubber  through  the  washing 
machine,  it  is  washed  in  4  per  cent,  formalin. 

Moisture,  Washing  and  Putrefaction. 

In  some  cases  it  is  doubtful  whether  it  is  even  necessary  to  add 
antiseptic  re-agents  if  it  is  intended  to  turn  the  rubber  out 
thoroughly  dried,  as  decomposition  is  more  or  less  dependent  upon 
a  supply  of  water  being  present. 

No  matter  whether  the  latex  has  been  treated  with  antiseptics 
or  not,  the  coagulated  substance  should  be  very  well  washed  ;  too 
much  water  cannot  be  used.  In  the  washing  processes  the  water 
may  carry  away  a  considerable  portion  of  the  soluble  protein  or 
that  precipitated  on  the  surface,  and  thus  minimise  the  danger. 


PARA     RUBBER  341 

The  use  of  washing  machinery  or  antiseptics  or  both  is  almost 
certain  to  become  a  necessity  in  the  near  future,  judging  by  the 
reports  of  European  firms  on  the  ondition  of  various  packages  of 
plantation  rubber  which  they  have  received.  Dilution  of  the  latex 
before  coagulation  might  also  reduce  the  proportion  of  protein  in  the 
prepared  rubber.  The  more  quickly  and  effectively  the  rubber 
is  dried,  the  less  likelihood  is  there  of  putrefaction  or  tackiness 
setting  in. 

Removal  of  the  Protein  from  the  Latex. 

But  it  is  not  beyond  the  ingenuity  of  the  chemist  or  planter  to 
treat  the  latex  with  some  re-agent  which  will  keep  some  proteins  in 
solution  while  the  caoutchouc  globules  are  segregating  ;  those  which 
form  part  of  the  rubber  can  be  expelled  by  subsequent  pressing, 
macerating,  and  washing.  Henri,  Spence  and  Dunstan  believe 
that  coagulation  can  be  effected  after  the  removal  of  all  protein 
substances  from  the  latex. 

Weber,  as  the  result  of  experiments  mainly  with  Castilloa 
latex,  suggested  that  the  treatment  of  dilute  hot  solutions  of 
latex  with  formaldehyde  (formalin),  or  the  use  of  the  latter  with 
sodium  sulphate,  may  be  effective  in  reducing  the  amount  of 
protein  matter  in  prepared  rubber  : — 

"To  every  gallon  of  the  rubber  latex,  from  i  oz.  to  i  oz.  of 
formalin  is  added  the  latex  well  stirred,  and  allowed  to  stand  for  one 
hour.  Then  to  each  gallon  of  latex  a  solution  of  i  lb.  of  sodium 
sulphate  (commercial)  in  one  pint  of  boiling  water  is  added  while 
still  hot,  and  the  mixture  stirred  for  some  time.  Coagulation  may 
take  place  immediately  or  after  several  hours'  standing,  according 
to  the  condition  of  the  latex.  Great  care  must  be  taken  to  use  a 
sodium  sulphate  of  entirely  neutral  re-action. 

' '  What  actually  happens  is  this  :  The  diluted  rubber  milk, 
freed  from  all  its  mechanical  impurities  by  straining,  is,  to  begin 
with,  rendered  non-coagulable  by  the  addition  of  the  formaldehyde. 
On  adding  to  the  rubber  milk  the  solution  of  sodium  sulphate  the 
rubber  substance  rapidly  rises  to  the  top,  where  at  first  it  forms  a 
very  thick,  creamy  mass,  the  individual  globules  of  which  rapidly 
coalesce.  The  coalesced  (and  as  a  matter  of  fact,  not  coagulated) 
mass,  on  being  worked  upon  the  washing  rollers,  undergoes  a  very 
curious  polymerisation  process,  and  thereby  rapidly  acquires  the 
great  strength  and  toughness  so  characteristic  of  high-class  india- 
rubber. 

' '  On  cutting  the  cake  open  it  will  be  found  to  be  rather  spongy, 
being  full  of  little  holes  which  are  still  filled  with  some  of  the 
albuminous,  though  very  dilute,  mother  liquor.  If,  therefore,  the 
rubber  were  dried  in  this  state,  it  is  obvious  that  it  would  still 
contain  a  small  quantity  of  the  objectionable  albuminous  matter. 
For  this  reason  the  rubber  so  obtained  should  at  once  be  taken, 
cut  into  strips,  and  subjected  to  a  thorough  washing  upon  ah 
ordinary  rubber  washing  machine. ' '  The  formalin  acts  more  as  an 
antiseptic  to  prevent  the  decomposition  of  the  protein  than  any- 


342  PARA    RUBBER 

thing  else,  and  does  not  affect  the  specific  gravity  of  the  mother 
liquor. 

Johnson  made  several  attempts,  when  Director  on  the  Gold 
Coast,  to  separate  rubber  from  Hevea  latex  in  the  manner  above 
suggested,  but  failed  in  each  instance,  although  the  latex  stood, 
in  one  or  two  trials,  for  nearly  three  weeks  without  the  rubber 
separating  out. 

This  method  has  been  tried  by  many  persons,  and  evidently 
requires  further  experiments  before  it  can  be  pronounced  as  perfect. 
It  should  be  remembered  that  certain  re- agents,  e.g.,  ammonia, 
&c.,  will  keep  the  latex  in  a  liquid  state  for  a  very  long  time,  and 
might  be  used  with  advantage  in  such  experiments. 

Darkening  of  Rubber  :    Proteins  and  Enzymes. 

It  being  very  desirable  that  rubber  should  be  sent  to  the 
market  in  as  pale  a  condition  as  is  possible,  some  attention  has 
been  given  to  methods  of  destroying  or  removing  the  substances 
causing  the  darkening.  Bamber  (Straits  Bulletin,  August,  1908), 
states  that  : — 

"The  discoloration  is  due  to  oxidation,  by  means  of  an 
oxidising  enzyme,  of  soluble  organic  bodies  alhed  to  tannin  in  the 
latex,  and  is  intensified  by  a  warm  temperature  and  exposure  to  the 
air.  Thorough  washing  of  the  freshly-coagulated  caoutchouc  will 
remove  much  of  the  soluble  matter  with  the  enzyme,  but  it  is 
difficult  or  impossible  to  remove  it  all,  and  other  means  have  to  be 
adopted  to  prevent  the  darkening  on  drying  which  almost  in- 
variably occurs.  This  is  done  by  destroying  the  enzyme  bj'  means 
of  heat  before  oxidation  occurs,  with  the  result  that  the  rubber 
dries  a  clear  pale  yellow  colour,  and  of  perfect  uniformity  from  day 
to  day.  The  heating  can  be  done  in  different  ways  before  or  after 
coagulation  :  ist.  By  passing  steam  into  the  bulked  latex  until 
the  temperature  reaches  8o°C.  (or  i67°F.),  and  maintaining  this 
temperature  for  15  minutes  or  longer,  according  to  the  thickness 
of  the  rubber.  2nd.  By  imrnersing  the  biscuits  or  sheets,  etc., 
in  water  of  this  temperature  for  some  minutes  immediately  after 
passing  through  the  above  rolling  machine  ;  then  re-rolling  to  the 
requisite  thinness,  and  immersing  again  for  a  shorter  time  to 
ensure  destruction  of  the  enzyme.  3rd.  Hot  water  can  be 
employed  in  the  washing  machine,  and  if  necessary  steam-heated 
rollers  as  well. ' ' 

A  different  position  is  taken  up  by  Spence  (Indiarubber 
Exhibition  Lectures,  1908),  who,  to  begin  with,  considers  that  the 
dark-coloured  bodies  are  formed  by  the  oxidation  of  proteins  by 
means  of  an  oxidising  enzyme,  and  who,  further,  denies  the 
efficiency  of  the  methods  suggested  by  Bamber.  He  admits  that, 
as  shown  by  his  own  experiments,  on  heating  an  extract  containing 
the  enzymes,  say,  at  8o°C.  for  5  minutes,  they  are  destroyed.  But 
he  points  out  that  all  enzymes  arise  from  bodies  known  as 
zymogens,  which  are  resistant  even  to  boiling.  Thus,  after 
treatment  of  crude  rubber  by  heat  for  the  destruction  of  the 


PARA     RUBBER  343 

enzymes,  new  enzyme  is  formed.  Yet  the  aggregate  activity 
has  been  lessened  by  the  process.  The  heating  method,  as  apphed 
to  some  latices,  may  possibly  ensure  light-coloured  rubber,  but  as 
applied  to  the  latices  from  old  trees,  it  is  doomed  to  failure  apart 
from  the  injury  that  may  be  done  to  the  rubber  by  heating  the 
latex.  He  recommends  that  if  light-coloured  rubber  is  desired, 
the  enzymes  and  proteins  be  removed  from  the  latex  by  suitable 
methods  of  washing  before  the  rubber  is  finally  coagulated.  By 
this  he  evidently  implies  washing  the  rubber  during  the  early 
stages  of  coagulation,  when  it  is  in  the  form  of  flakes,  a  process 
that  he  claimed  to  have  carried  out.  But  no  proposals  have  yet 
been  made  for  following  out  the  process  on  a  commercial  scale,  and 
Spence  himself  (I.R.J.,  April,  1911),  has  recently  admitted  that 
the  removal  of  the  proteins  from  crude  rubber  is  a  matter  of  much 
difficulty.  A  private  communication  from  Crossley  is  to  the  same 
effect. 

It  is  worthy  of  note  that  Messrs.  Lewis  and  Peat,  in  their 
1910  circular,  remark  that  the  trade  generally  now  look  far  more 
to  the  quality  and  strength  of  plantation  rubber  than  to  colour. 

Discoloration   of   Biscuits. 

The  government  mycologist,  Ceylon,  reported  that  in  1909 
various  cases  of  discoloration  to  rubber  biscuits,  e.g.,  red  patches, 
black  spots,  and  biscuits  with  a  brown  film,  had  been  examined  as 
far  as  possible.  Some  of  these  discolorations  appear  to  be  due  to 
bacteria  and  yeasts,  and  can  be  avoided  by  scalding  the  various 
utensils  used  in  the  factory  ;  others  appear  to  be  due  to  chemical 
differences,  and  these  are  now  being  analysed. 

When  this  trouble  makes  its  appearance,  all  collecting  cups 
should  be  boiled,  and  the  dishes,  pails,  etc.,  scalded  with  boiling 
water.  It  has  been  found  sufficient  to  do  this  once,  but  it  would 
be  a  wise  precaution  to  scald  the  dishes  and  pails  periodically, 
as  part  of  the  general  routine  of  the  factory.  If  the  infection  is 
introduced  with  the  water-supply,  the  above  treatment  will  not 
stop  it,  because  the  dishes  will  be  re-infected.  To  determine 
whether  the  water  supply  is  at  fault,  biscuits  should  be  made, 
using  water  which  has  been  boiled  and  cooled,  and  these  should 
be  compared  with  biscuits  made  with  the  unboiled  water. 

According  to  Brooks,  the  red  patches  are  due  to  infection  by 
Bacillus  prodigiosus. 

Moulds    on    Rubber. 

An  examination  of  the  rubbers  from  various  countries  was 
carried  out  in  Ceylon  (Annual  Report,  1906),  in  order  to  determine 
their  comparative  resistance  to  moulds.  The  mould  which  grows 
on  prepared  rubber  in  Ceylon  is  apparently  Eurotium  candidum. 
It  seems  clear  as  a  result  of  the  inquiry  that  the  development 
of  the  moulds  depended  upon  the  moisture  content  of  the  rubbers, 
the  driest  rubbers  escaping  attack. 


'H  AFTER   XXII. 

THE    THEORY     OF    COAGULATION. 

The  physical  and  chemical  changes  involved  in  the  phases  of 
coagulation  already  recognised  are  numerous  and  complex,  and 
many  theories  have  been  put  forward  to  explain  the  phenomenon. 
It  may  be  argued  that  the  practical  planter  does  not  need  to 
trouble  himself  about  the  changes  which  lead  to  the  separation  of 
rubber  from  the  latex,  since  this  is  so  easily  accomplished.  The 
writer  is  of  the  opinion,  however,  that  the  methods  adopted  on 
Eastern  estates  still  leave  much  to  be  desired,  and  if  a  better 
knowledge  of  the  changes  incurred  during  coagulation  can  be 
gained,  planters  of  an  inventive  frame  of  mind  will  quickly  effect 
improvements.  For  these  reasons,  it  is  proposed  to  study  the 
phenomena  of  coagulation  in  some  detail,  and  to  consider  latices 
from  species  other  than  Hevea  brasiliensis. 

The  latices  from  different  species  alike  possess  quantities  of 
resins,  proteins,  caoutchouc  and  inorganic  substances,  but  the 
behaviour  of  these  to  the  same  agencies — heat,  moisture,  centri- 
fugal force,  preservatives,  acids,  and  alkalies — ^is  widely  different. 
The  phases  of  coagulation  of  latices  from  distinct  botanical  sources 
require  separate  and  detailed  investigation.  Heat,  though  it 
coagulates  many  latices,  has  no  such  effect  on  that  of  Hevea 
brasiliensis.  Formaldehyde,  though  acting  as  an  anti-coagulant 
with  Hevea  latex,  appears  to  coagulate  other  latices.  Alkalies, 
which  help  to  maintain  some  latices  in  a  liquid  condition,  hasten 
the  coagulation  of  others.  Mechanical  means,  while  allowing  one 
to  effectively  separate  large-sized  caoutchouc  globules  from  some 
latices,  are  almost  useless  when  dealing  with  the  latex  of  Hevea 
brasiliensis. 

The  Theory  of  Coagulation. 

The  changes  that  are  essential  in  the  production  of  an  elastic 
mass  of  indiarubber  from  the  latex  have  been  variously  explained, 
but  only  two  views  will  be  here  referred  to.  Some  hold  that  the 
necessary  factor  is  the  formation  of  a  network  of  coagulating 
protein  that  brings  the  globules  together  as  it  contracts.  Others 
maintain  that  coagulation  is  independent  of  the  proteins,  can 
take  place  in  their  absence,  and  is  explicable  only  by  modern 
physico-chemical'  theories  of  the  suspension  of  colloid  particles 
in  an  emulsion.  That  the  coagulation  of  the  protein  is  responsible 
seems  a  very  attractive  explanation  when  one  recalls  the  clotting 


PARA     RUBBER  345. 

of  ordinary  milk  under  the  influence  of  rennet.  But  this  view 
of  coagulation  has  been  strongly  attacked  by,  among  others, 
Spence,  Dunstan,  and  Henri. 

The  term  ' '  coagulation ' '  was  originally  applied  to  the  coagula- 
tion of  protein,  but  it  is  now  generally  used  to  denote  the  separa- 
tion of  the  caoutchouc  globules  and  all  those  processes  which  lead 
to  the  production  of  a  mass  of  rubber  from  latex. 

Proteins  and  Coagulation. 

Dunstan  (Bull.  Imp.  Inst.,  Vol.  IV.,  No.  4,  1906),  has  pointed 
out  that  the  original  view  taken  of  the  process  of  coagulation — 
to  the  effect  that  it  was  dependent  upon  protein  coagulation  and 
the  separated  proteins  carrying  the  rubber  globules  with  them — 
cannot  now  be  accepted.  Dunstan  asserts  that  ' '  there  are 
peculiarities  connected  with  the  coagulation  of  latex  which  are 
opposed  to  the  view  that  it  is  wholly  explained  by  the  coagulation 
of  the  associated  proteins.  Experiments,  made  with  latex  from 
India,  led  them  to  the  conclusion  that  'coagulation'  can  take 
place  after  removal  of  the  proteins,  and  that  in  all  probability  it 
is  the  result  of  the  polymerisation  of  a  liquid  which  is  held  in 
suspension  in  the  latex  and  that  on  polymerisation  changes  into 
the  solid  colloid  which  we  know  as  caoutchouc.  There  is  little 
room  for  doubt  that  the,  coagulation  is  due  to  the  '  condensation ' 
or  polymerisation  of  a  liquid  contained  in  the  latex.  What 
is  the  nature  of  this  liquid  from  which  caoutchouc  is  formed  ?  ' '' 

Physico-Chemical  Theory  of  Coagulation. 

Henri  (Le  Caoutchouc,  May  15th,  1907),  who  carried  out 
a  series  of  experiments  with  the  latex  of  Hewa  hrasiliensis,  pointed 
out  that  in  connection  with  the  coagulation  of  latex  there  exists 
a  series  of  bodies  which  cause  coagulation  in  some  samples,  but 
have  no  effect  on  others  ;  he  also  remarks  that  the  coagulation 
of  latex  has  been  compared  with  that  of  albuminoids,  it  even  being 
surmised  that  these  substances  are  essential  to  the  process.  He 
maintains,  however,  that  latex  is  really  a  suspension  of  very 
fine  particles  in  aqueous  liquid  more  or  less  rich  in  saline  or  organic 
bodies,  is  of  the  nature  of  an  emulsion,  and  that  the  same  laws 
rule  as  in  the  precipitation  of  colloids  from  emulsions.  The  fact  that 
rubber,  owing  to  its  lightness,  rises  to  the  surface  instead 
of  being  precipitated  does  not  affect  the  comparison.  Having 
electrically  tested  Hevea  latex,  he  found  that  the  globules  were 
negatiye  as  to  the  serum.  And,  as  he  points  out,  the  precipitation 
of  negative  emulsions,  or  rather,  of  the  suspended  particles,  is 
brought  about  by  acids  or  the  salts  of  bi-  and  tri-valent  metals, 
without  any  distinction  as  to  the  nature  of  the  acids  of  these  salts  ; 
while  the  precipitation  of  positive  emulsions  is  brought  about  by 
alkalies  or  the  salts  of  bi-  and  tri-basic  acids,  the  nature  of  the 
metallic  bases  of  these  salts  being  of  no  importance.  This  close 
analogy  with  an  emulsion  he  regards  as  of  great  significance. 


346  PARA     RUBBER 

FiCKENDEY    ON     PROTECTIVE     COLLOIDS. 

By  Fickendey  (Zeits.  Chem.  Ind.  Kolloide,  1910),  the  term 
' '  coalescence ' '  is  preferred  to  that  of  ' '  coagulation. ' '  The 
stability  of  latex  emulsions,  that  is,  their  power  of  retaining  the 
caoutchouc  globules  in  suspension,  he  ascribes  to  what  he  calls 
the  protective  colloids,  the  proteins,  as  in  Hevea  latex,  or  the 
peptones,  as  in  Funtumia  latex.  The  first  phase  in  coalescence, 
really  comparable  to  creaming  of  the  globules,  depends  directly 
upon  the  behaviour  of  the  colloids.  Protein  precipitants  cause 
separation  of  the  rubber  in  latices  containing  proteins,  as  in 
Hevea  latex ;  peptone  precipitants  cause  separation  of  rubber  in 
latices  containing  peptones,  as  in  Funtumia,  where  formahn  is  a 
coagulant  because  it  is  a  peptone  precipitant.  If  freshly-separ- 
ated rubber  cream  from  Funtumia  latex  is  shaken  up  with  peptone 
solution,  a  stable  emulsion  is  formed.  The  same  happens  if 
cream  from  Castilloa  latex  is  shaken  up  with  albumen  solution. 
The  second  phase  of  coalescence  has  been  regarded  as  one  of 
polymerisation,  though  experimental  proof  is  wanting.  It  is 
accepted  by  him  that  liquefaction  or  destruction  of  the  separate 
globules  precedes  the  transformation  of  the  liquid  caoutchouc 
into  the  elastic  modification.  He  cannot  confirm  Schidrowitz's 
statement  that  the  globular  form  persists  in  the  crude  rubber. 

Polymerisation   of  the   Caoutchouc. 

This  question  of  polymerisation  of  the  caoutchouc  hydro- 
carbon during  the  production  of  the  rubber  is  still  a  matter  of 
debate.  Polymerisation  is  a  chemical  change,  but  not  one  in- 
volving any  alteratiorf  in  the  relative  quantity  of  the  constituents, 
being  merely  what  may  roughly  be  called  a  condensation,  a 
substance  of  higher  molecular  weight  being  formed.  Probably, 
this  chemical  change,  if  it  takes  place,  is  accompanied  by  a  physical 
change,  to  a  more  solid  condition. 

Some  investigators  hold  that  the  caoutchouc,  as  we  find  it 
in  the  crude  rubber,  is  already  formed  as  such  in  the  latex,  but 
others  differ.  Weber  believed  that  in  the  latex  caoutchouc 
exists  as  a  thin,  oily  liquid. 

Apparently  the  only  investigations  bearing  upon  this  question 
of  polymerisation  are  two  in  number.  Hinrichsen  and  Kindscher 
find  that  the  caoutchouc  has  already,  in  the  latex,  a  very  high 
molecular  weight,  a  fact  that  is  against  the  idea  that  polymerisa- 
tion takes  place  during  coagulation.  Harries  got  colloida:l  solu- 
tions by  treating  fresh  latex  with  ether — another  indication  of 
high  molecular  weight. 

It  must  not  be  assumed  that  polymerisation  is  an  incident 
only  in  coagulation,  or  that  it  necessarily  takes  place  at  that  stage. 
Harries  apparently  believes  that  polymerisation  mav  take  place 
during  the  drying  and  smoking  of  the  rubben 


PARA     RUBBER  347 

Phases    of    Coagulation. 

As  the  result  of  his  experiments  Henri  concluded  that  "On 
adding  different  reagents  to  the  latex  one  of  three  things  may 
occur  : — 

"i.  There  is  no  reaction. 

"2.  Isolated  flakes,  varying  in  size,  are  formed  which  either  rise 
or  sink,  but  do  not  unite,  being  readily  separated  by  stirring.  This 
may  be  termed  the  agglutination  of  the  latex. 

"3.  A  network  of  long  threads  encircling  all  the  globules  of  the 
latex  is  observed.  On  stirring,  the  threads  reunite,  forming  a 
solid  elastic  coagulum.     This  is  the  true  coagulation  of  the  latex." 

Agglutination  or  coalescence  of  the  caoutchouc  globules  is 
therefore  the  first  stage  in  coagulation.  It  is  conceivable,  when  the 
caoutchouc  is  entirely  separated  from  the  other  constituents  of  the 
latex,  that  this  may  also  be  the  only  and  therefore  final  stage. 

Effect  of   Re-agents   on   Latex. 

Henri  performed  his  experiments  upon  dialysed  latex,  that 
is,  latex  from  which  the  salts  and  other  crystalline  bodies  were 
removed.  A  large  number  of  re-agents,  singly  and  in  mixtures, 
were  tried  with  the  following  results  : — 

"Methyl,  ethyl  and  amyl  alcohol  produced  no  reaction. 
Hitherto  alcohol  has  been  considered  a  coagulant,  but  its  action 
is  evidently  due  to  salts  present  in  the  latex.  Sodium,  potassium, 
and  ammonium  salts  also  have  no  effect.  Salts  of  calcium,  barium 
and  magnesium  in  sufficient  quantities  cause  agglutination. 
Salts  of  iron,  manganese,  nickel,  cobalt,  copper,  zinc,  lead,  and 
aluminium  all  produce  agglutination,  the  size  of  the  flakes  increasing 
with  increase  in  concentration  of  the  solutions,  but  one  never  got  an 
elastic  clot.  Hydrochloric,  nitric  and  acetic  acids  all  cause 
agglutination  ;  very  dilute  sulphuric  acid  also  has  the  same  effect, 
but  if  more  concentrated,  coagulation  commences.  Trichloracetic 
acid,  even  when  very  dilute,  produces  a  remarkably  elastic 
coagulum.  Acetone  also  is  a  coagulant. ' ' 

"  Regarding  the  action  of  mixtures,  as  a  rule  alcohol  added 
after  a  salt  produces  agglutination  or  coagulation. 

On  studying  the  influence  of  alkalies  on  coagulation,  it  was 
found  that  an  extremely  small  quantity  interfered  with  the 
reaction  ;  a  ten- thousandth  normal  solution  was  sufficient  to 
prevent  agglutination  or  transform  coagulation  into  agglutination. 
Thus  magnesium  chloride  and  alcohol  produce  coagulation,  but 
if  the  latex  is  rendered  even  very  slightly  alkaline,  only  isolated 
flakes  are  formed,  again  showing  that  the  passage  from  agglutina- 
tion to  coagulation  is  gradual,  and  that  one  may  be  considered 
as  a  higher  stage  of  the  other. ' ' 

Generalisations    by    Henri    from    his    Experiments. 

Some  of  the  deductions  made  by  Henri  from  his  experiments 
are  as  follows  : — 

I.  Coagulation  by  mixtures  is  much  superior  to  that  by  single 
substances. 


348 


PARA     RUBBER 


2.  It  is  by  the  association  of  acids  with  the  salts  of  bivalent 
and  trivalent  metals  that  the  best  results  are  obtained. 

3.  Coagulation  by  mixtures  should  not  be  too  rapid,  other- 
wise some  parts  are  less  efficiently  coagulated  than  others.  Agita- 
tion helps  coagulation. 

4.  The  temperature  at  which  the  coagulant  is  added  is  of 
importance.  The  best  results  are  in  certain  cases  obtained  by 
first  adding  a  very  small  quantity  of  the  mixture,  not  enough  to 
produce  coagulation,  and  then  raising  the  temperature  to  25°  or 
30°  C.  The  rubber  obtained  is  very  homogeneous,  of  good  nerve, 
elastic,  and  generally  of  superior  quality.  Evaporation  of  water 
is  here,  of  course,  one  of  the  agents  in  coagulation. 

5.  The  mixtures  giving  the  most  elastic  rubber  are  not  those 
giving  the  best  rubber  for  solution  in  benzene. 

Comparative  Coagulating  Power  of  Different  Chemicals. 

The  coagulating  power  of  chemical  substances  varies  within 
fairly  wide  limits,  and  in  the  table  below  Parkin  (Science  Progress, 
April,  1910),  gives  the  weight  required  of  different  re-agents  to 
coagulate  completely  100  c.c.  of  Hevea  latex. 

Grammes  per  100  c.c. 
of  latex. 
Sulphuric  acid  .  .  .  .     o-i 

Hydrochloric  acid       . .  . .  . .      o-i 

Nitric  acid        .  .  .  .  .  .  .  .      0-3 

Acetic  acid  . .     0-95 

Oxalic  acid       .  .  . .  o'2 

Tartaric  acid   .  .  .  .  . .  .  .     0-25 

Citric  acid        . .  . .  . .  .  .      0'5 

Corrosive  sublimate   .  .  . .  . .     o-8 

Formic  acid     . .  . .  . .  .  .      0-45 

Acid  potassium  tartrate        ..  ..     0'i6 

It  will  be  observed  that  acetic  acid  is  the  least  powerful  of 
these  re-agents  ,'but,  leaving  all  other  considerations  out  of  account, 
this  has  its  advantage  in  that  greater  freedom  is  possible  in  the 
amount  of  acid  used. 


Structureof  C^u    e  Rubber. 

Torrey  (I.R.J. ,  Nov.,  1907)  points  out  that  Henri  gives  a 
series  of  plates  showing  the  structure  of  the  rubber  obtained 
by  coagulation  of  the  latex  with  different  re-agents,  and  shows 
that  the  same  latex  yields  products  of  totally  different  character 
(as  to  length  of  fibre,  elasticity  and  hfe)  according  to  the  re-agent 
by  which  it  is  coagulated.  Sometimes  the  rubber  separates  in  the 
form  of  fine  flecks  which  show  little  or  no  tendency  to  unite  with 
other  coagulants,  the  flecks  either  unite  to  form  larger  flecks,  or 
one  obtains  at  once  a  deposit  which  from  the  first  has  a  lace-like 
structure.  In  these  latter  cases  the  product  is  very  elastic  ;  in  the 
first  case  it  is  notably  less  so. 

Some  years  ago  Torrey  observed  that  "petroleum  naphtha 
solutions  of  a  number  of  crude  unwashed  rubbers  gave  charac- 
teristic figures  when  a  few  drops  were  allowed  to  evaporate  on  a 


PARA     RUBBER  349 

white  surface.  The  solutions  consisted  of  5  grams  of  each  rubber 
in  100  CO.,  petroleum  naphtha  boiling  at  60  deg.  to  90  deg.  C.  I 
recall  that  Fine  Para  and  Matto  Grosso  were  the  two  South 
American  grades  ;  and  among  the  Africans  were  Lapori,  Red 
Kasai,  Upper  Congo  Ball,  Ikelemba  and  Bussira. ' ' 

' '  Fine  Para  gave  always  a  fine  regular  lace-like  pattern  ; 
Matto  Grosso  gave  a  very  similar  one,  but  not  so  fine  and  not 
so  regular.  Some  of  the  African  gave  the  same  general  type  of 
figure,  but  much  coarser.  Others  deposited  the  rubber  in  the  form 
of  one  or  two  nebulous  spots,  shading  away  very  gradually  toward 
the  edges,  and  connected  by  a  few  rather  faint  filaments  which 
were  usually  disposed  between  the  two  spots  in  the  form  of  a 
single  mesh  of  a  coarse  network — the  mesh  being  approximately 
circular  in  form.  The  most  characteristic  case  of  this  kind  was 
Lapori.  On  the  whole,  the  difference  between  the  figures  cor- 
responding to  dirferent  rubbers  was  so  great  that  even  an  untrained 
observer  could,  without  difficulty,  identify  almost  any  one  of  the 
varieties  under  examination  by  its  figure. ' ' 

These  results  seem  to  be  explained  differently  by  the  experi- 
ments of  Fox  (I.R.J.,  January,  1909).  A  large  number  of  samples 
representing  the  most  important  of  the  wild  and  cultivated  species 
were  tested  according  to  Torrey's  method.  Fox  was  able  to  show 
that  the  pattern  of  the  films  left  after  evaporation  of  the  solvent 
depended  entirely  upon  the  viscosity  of  the  solution.  This  in 
turn  depends  mainly  upon  the  concentration  of  the  solution  and 
partly  upon  the  degree  of  impurity  of  the  crude  rubber. 

Influence  of  Coagulant  on  Strength  of  Rubber. 

The  observations  of  Henri  regarding  the  influence  of  the 
various  coagulants  on  the  strength  of  the  rubber  are  extremely 
important  to  planters.  If  the  re-agents  which  are  now  so  largely 
used  on  Eastern  estates  produce  an  inferior  rubber,  others  should 
be  taken  up.  Henri  claims  to  have  proved  that  ' '  the  structure  of 
the  coagulum  varies  with  the  nature  and  concentration  of  the 
substances  employed  for  coagulation.  A  weak  coagulant  produces 
a  pulverulent  or  flaky  precipitate  ;  a  strong  coagulant,  on  the 
contrary,  leads  to  the  formation  of  an  elastic  curd  with  reticular 
'•structure.  When  the  structure  of  the  reticular  curd  obtained  by 
different  coagulating  agents  is  considered  it  is  seen  that  the 
■  smallness  of  the  meshes  varies  with  the  coagulant  and  speed 
of  coagulation.  The  elastic  properties  of  rubber  obtained  by 
coagulation  of  the  same  latex  vary  much  with  the  different  coagu- 
lants employed. ' ' 

And  it  may  be  taken  in  a  general  sense  that  a  tougher  rubber, 
but  one  with  less  distensibility,  results  from  a  more  rapid  coagula- 
tion. 

The  curds  which  Henri  obtained  by  coagulation  of  latex 
were  rolled  out  in  sheets,  dried,  cut  into  strips  and  mechanically 
tested.  The  following  were  his  results.  (The  last  column  gives 
■elongations  at  moment  of  rupture)  : — 


pture  Stress  per 

millimetre. 

Elongations. 

150  g- 

8-5 

190 

7-2 

175 

7-5 

3ZO 

7-1 

325 

6-8 

3  Id 

6-8 

380 

6-8 

660 

6-5 

.150  PARA     RUBBER 


Mode  of  Coagulation. 
Heat  80  deg.  C. 
Heat  25  deg.  C. 
Weak  acetic  acid 
Strong  acetic  acid 
Trichloracetic  acid 
Acid  +  salt  i 
Acid  +  salt  2 
Acid  +  saJt  3 

' '  The  elastic  properties  of  rubber  are  therefore  considered  to 
be  in  relation  with  the  fineness  of  the  reticular  structure  of  the 
curd,  and  the  latter  depends  upon  the  coagulant  employed. 
Thus  with  the  same  latex  Henri  showed  that  rubbers  with 
different  values  can  be  obtained,  a  most  important  determination 
to  all  rubber  planters. 

Henri's  observation — that  the  fineness  of  the  reticular  struc- 
ture depends  on  the  nature  of  the  coagulant  and  the  rate  of 
coagulation — has  been  confirmed  by  Spence  for  Funtumia  rubber 
(I.R.J.,  August,  1907),  who  states  that  the  elastic  properties  of 
rubber  may  vary  with  the  coagulant  employed.  This  is  a  point 
which  should  be  well  studied  by  all  planters  who  are  anxious  to 
improve  the  physical  .properties  of  their  rubber.  If  the  acetic 
acid  so  largely  used  on  Eastern  estates  produces  an  inferior  rubber, 
its  use  should  be  discontinued  and  the  latest  results  of  science  given 
a  practical  trial  on  a  large  scale.  There  is  no  time  to  be  wasted  in 
this  direction,  especially  on  plantations  where  all  the  trees  are  young. 
.  Spence  is  of  the  opinion,  from  his  analyses  of  Funtumia  elastica 
latex  and  rubber,  that  if  the  nitrogenous  compounds  in  latex  could 
be  broken  up  in  a  particular  manner,  the  quality  of  the  final  rubber 
might  be  considerably  improved.  Is  this  also  likely  with  Hevea 
latex  ? 

Further  Observations  on  Effect  of  Coagulation  on 
Strength. 

Without  mentioning  the  methods  of  coagulation  employed, 
Schidrowitz  (Rubber,  1911)  mentions  that  in  a  series  of  three 
samples  of  Funtumia  rubber  prepared  by  different  methods,  the 
best  sample  had  a  viscosity  value  of  17,400  and  the  poorest  one  of 
12,800,  that  of  benzene  being  unity.  In  a  series  of  ten  samples, 
all  the  product  of  different  methods,  the  limits  were  18,500  and 
11,400.  These  figures  enforce  the  importance  of  our  determining 
carefully  the  best  methods  of  production. 

In  an  earlier  communication  that  he  made  along  with  Kaye 
(I.R.J. ,  23rd  Sept.,  1907),  wide  variations  were  found  in  samples 
of  Funtumia  rubber  coagulated  in  different  ways,  as  by  heating, 
and  with  calcium  chloride,  acetone,  etc.  The  pure  caoutchouc, 
that  is,  the  soluble  rubber  free  from  water  and  resin,  ranged  in 
quantity  from  77-6  to  94-32  per  cent,  of  the  latex.  The  tensile 
strengths  (breaking  strains)  varied  between  217  and  nearly  500  ; 
elongation  at  break  was  between  3-8  and  6-6  ;  the  range  in  resiliency 
was  from  54  to  100  per  cent. 


PARA     RUBBER  351 

Coagulant  and  Strength  of   Vulcanized  Rubber. 

Frank  and  Marckwald  (Gummi-Zeitung,  XXV.,  1911,  pp.  193 
and  877),  prepared  Ceara  and  Funtumia  rubber  by  numerous 
methods,  varying  the  methods  of  drying  and  after-preparation  as 
well  as  those  of  coagulation.  All  the  samples  were  vulcanized, 
and  then  tested  for  elongation  at  break  and  the  breaking  stress  ; 
the  viscosity  was  also  determined,  and  the  free  and  combined 
sulphur.  A  very  wide  variation  in  mechanical  qualities  and  in 
behaviour  under  vulcanization  was  shown. 

Messrs.  Clayton  Beadle  and  Stevens  (Chemical  News,  Novem- 
ber 22nd,  1907),  state  that  though  the  method  of  coagulation  may 
affect  the  physical  properties  (nerve)  of  raw  rubber,  the  difference 
in  reticulation  recorded  by  Henri  may  have  no  effect  on  the 
properties  of  the  ultimate  vulcanized  product.  At  the  temperature 
of  vulcanization  they  maintain  that  all  traces  of  structure  disappear, 
even  if  they  have  not  already  been  obliterated  in  the  process  of 
mastication.  They  should  not  lose  sight  of  the  fact,  however,  that 
raw  rubber  is  sold  by  producers  on  its  physical  properties  alone. 
Too  much  stress  cannot  be  laid  on  the  importance  of  preparing 
plantation  rubber  in  such  a  manner  that  its  nerve  shall,  if  possible, 
be  equal  to  that  of  fine  hard  Para. 

The  same  authors,  in  the  same  contribution,  point  out  that 
there  is  some  striking  proof  of  the  influence  of  the  conditions  under 
which  crude  rubber  is  prepared  on  its  physical  properties  in  the 
"apparent"  specific  gravity  of  the  rubbers  examined  by  them. 
The  specific  gravity  of  one  biscuit  was  low  corresponding  with  a 
low  tensile  strength.  That  of  a  block  was  lower  still  owing  to 
the  presence  of  a  large  number  of  air  bubbles.  Heating  a  block 
reduced  its  tensile  strength  ;  freezing  a  block  for  one  week  im- 
proved the  tensile  strength  without  materially  affecting  the  specific 
gravity. 


CHAPTER  XXIII. 

PURIFICATION    OF    RUBBER,    AND     WASHING 
MACHINES. 

Having  dealt  with  the  properties  of  latex  and  the  various 
methods  of  preparing  rubber  therefrom,  it  is  now  necessary  to 
consider  the  important  details  of  the  processes  through  which 
rubber  passes  in  purification,  and  its  condition  when  it  enters  the 
market.  It  is  possible  that  much  time  and  trouble  may  be 
saved,  and  at  the  same  time  a  rubber  of  higher  quality  be  produced, 
by  carrying  out  certain  purification  processes  in  the  initial  stages. 
The  condition  of  the  rubber  when  it  arrives  in  Europe  is  well 
known  to  most  cultivators,  as,  apart  from  the  usual  shrinkage, 
it  undergoes  no  changes  during  transit  if  it  has  been  properly 
prepared. 

Very  often  grades  of  washed  rubber,  prepared  carelessly,  con- 
tain nearly  20  per  cent,  of  impurities,  and  in  the  case  of  "scrap" 
rubber  the  question  of  purification  may  become  a  serious  one. 

Purification  by  the  Manufacturers. 
Scraps  of  fibre,  particles  of  sand,  abundance  of  resins, 
albuminoids,  and  mineral  matter  are  not  required  in  the  finished 
product,  and  the  mechanical  and  soluble  impurities  are,  as  far  as 
possible,  removed  by  the  manufacturer.  In  Europe  the  rubber  is 
first  cut  into  small  pieces  and  placed  in  tanks  containing  hot  or 
boiling  water.  It  is  then  put  t^trough  the  washing  machines,  the 
rollers  of  which  tear,  cut,  and  expose  all  parts  of  it  to  a  current  of 
clean  water.  The  success  of  this  method  depends  upon  the 
rubber  being  cut  into  sufficiently  small  pieces  and  soaked  for  the 
proper  length  of  time  in  water  maintained  at  the  desired  tempera- 
ture. The  washing  process  removes  every  kind  of  mechanical 
impurity,  the  fragments  of  fibre,  sand,  &c.,  flying  out  of  the 
softened  rubber  when  it  is  stretched  and  torn  between  the  rollers. 
These  impurities  are  loosely  embedded  in  the  rubber,  and  if  the 
temperature  is  raised  too  high  the  resins  may  be  converted  into 
sticky  substances,  which  cement  the  rubber  and  mechanical 
impurities  and  thus  render  it  impossible  to  remove  the  latter  by 
washing. 

Loss  IN  Washing  Wild  Rubbers. 
The  actual  loss  in  the  washing  process  is  often  surprising. 
The  loss  on  washing  some  of  the  Para  rubber  collected  in  the 
Amazon  district  varies  from  10  to  40  per  cent.  Biffen  states  that 
the  loss  in  the  factories  is  as  follows  for  different  grades  of  Para 
rubber  :— (i)  fine  Para,  10-15  per  cent.  ;  (2)  extra  fine,  the  care- 
lessly smoked  pieces,  15-20  per  cent.  ;    sernamby,  rubber  pulled 


PARA     RUBBER  353 

from  the  cuts  on  the  tree  and  cups,  20-40  per  cent.  Many  lots  of 
fine  wild  Para  have,  during  recent  times,  shown  a  loss  on  washing 
of  from  15-16  per  cent,  in  sarriples  containing  2-2  to  2-9  per  cent, 
of  resin  and  0-27  to  0-29  per  cent,  of  ash.  The  loss  from  fine 
Para  is  from  10  to  20  per  cent.,  whereas  that  from  plantation 
biscuit,  sheet,  crepe,  &c.,  is  only  about  i  per  cent.  Weber  states 
that  fine  hard  Para  from  the  Amazon  district  shows  a  loss  on 
washing  of  from  12  to  18  per  cent.,  and  contains  1-3  per  cent,  of 
resin  and  0-3  per  cent,  of  ash  in  the  dry  washed  material.  Cameta 
loses  40-50,  Peruvian  ball  or  Caucho,  20-40,  Mangabeira  (Han- 
cornia),  30-40,  Red  Kasai  (Landolphia),  20-30,  Gaboon  balls, 
25-35,  Upper  Congo,  10-30,  Panama  (Castilloa),  15-30,  and 
Pontianak,  10-50  per  cent,  on  washing. 

Different  brands  show  a  variation  in  the  composition  of  the 
impurities  and  the  loss  on  washing  as  indicated  below ;  the  com- 
position of  the  impurities  is  clearly  put  forward  by  Weber  : — 

Loss  on    Oily  and  Resinous 

Brand.  Washing.       Substances.  Ash. 

0/  0/  0/ 

/o  /o  /o 

Ceylon      . .  . .  . .  i  3*0  0-5 


Para,  hard  cure 
Para,  soft  cure 
Ceara 
Borneo 


15 
17 

48 


2-1 

^■5 

2-5 

0-3 

2-0 

274 

2-2 

2-2 

The  loss  on  washing  is  estimated  by  determining  the  yield  of 
dry  washed  rubber  obtainable  from  a  known  bulk  of  crude  rubber. 
The  crude  rubber  is  weighed  both  before  washing  and  after  drying, 
the  percentage  loss  then  being  calculated.  This  loss  consists 
mainly  of  water,  salts,  wood  fibres,  and  mineral  impurities.  The 
oily  substances  form  a  very  small  part  only  of  the  total  extract. 
Weber  states  that  the  resinous  matter  is  generally  semi-transparent, 
yellowish-brown,  or  brown  ;  in  sonde  cases  it  is  semi-resilient  and 
slightly  sticky,  sometimes  hard  and  brittle,  and  in  a  few  cases  is 
white  and  powdery  in  appearance. 

Many  persons  assume  that  the  percentage  of  resinous  matter 
in  indiarubber  is  an  indication  of  the  care  bestowed  upon  it  by  the 
producer.  This  is  not  correct,  for  the  resinous  matters  exist  in  the 
latex  as  the  latter  flows  from  the  trees.  The  variation  in  resin  in 
different  samples  of  the  same  brand  of  rubber  is  probably  due  to 
the  condition  or  age  of  the  tree  from  which  the  latex  is  obtained, 
or  to  the  mixing  of  latices  of  different  qualities. 

High  Loss  Undesirable. 

If  the  loss  on  washing  is  beyond  a  certain  amount  the  rubber 
will  be  naturally  classed  as  inferior.  In  a  paper  (I.R.  J.,  July  20, 1903) 
read  before  the  International  Congress  of  Applied  Chemistry  the 
following  interesting  passage  occurs  :  ' '  While  fifteen  years  ago 
fine  Para  rarely  showed  a  loss  in  washing  exceeding  from  10  to  12 
per  cent.,  this  rose  within  the  last  ten  years  from  12  to  16  per  cent., 
and  in  the  last  five  years  had  reached  from  15  to  20  per  cent. 
During  the  same  time  Colombia  Virgin,  at  one  time  one  of  the  finest 

w 


354  PARA     RUBBER. 

brands  of  rubber,  has  practically  entirely  disappeared  from  the 
market.  What  little  still  occurs  under  the  name  is  an  altogether 
inferior  product. ' ' 

Washing  Rubber  on  Plantations 
When  plantation  rubber  was  first  sent  from  the  East  it  was 
shipped  as  clean  biscuits  or  sheet  obtained  by  filtering  the  latex 
through  cloth,  adding  acetic  acid  to  hasten  coagulation,  and 
thoroughly  washing  the  soft  freshly-coagulated  rubber  with  clean 
water.  Such  methods  of  preparation,  while  useful  from  the 
standpoint  of  purity  in  composition  and  ease  in  packing,  are  not 
applicable  when  estates  are  harvesting  several  tons  each  month  ; 
the  use  of  separate  trays,  for  biscuits  or  sheets  weighing  only  a  few 
ounces  each  when  dry,  must  give  way  to  a  more  practical  method 
for  dealing  with  large  crops. 

The  use  of  machinery  is  bound  to  become  more  general 
when  more  rubber  is  collected  ;  the  means  adopted  for  straining, 
purif5dng,  and  coagulating  the  latex  will  minimise  the  loss  which 
normally  occu;s  in  the  manufacturing  process. 

Characters  of  Washed  Rubber. 

If  the  washing  process  has  been  properly  carried  out,  the 
rubber  should  dry  rapidly  and  give  a  pale  amber-coloured  final 
product.  The  unevenness  depends  upon  the  cut  of  the  rollers  and 
the  number  of  times  the  rubber  has  been  operated  upon.  Often 
the  rubber  has  been  torn  and  stretched  beyond  all  requirements. 
Thoroughly-washed  rubber  does  not  usually  show  any  signs  of 
mould  or  tackiness  ;  crepe — probably  on  account  of  the  washing  to 
which  it  has  been  subjected — is  rarely  known  to  arrive  in  Europe 
in  a  mouldy  condition  ;  this  cannot  be  said  of  most  other  forms. 
Where  machinery  is  defective,  the  strips  of  crepe  may  have  dirty 
or  oily  patches  which  disfigure  the  consignment  ;  these  defects 
can,  however,  be  remedied. 

Practical   Points  in   Washing   Rubber. 

Properly  washed  plantation  rubber  is  now  sometimes  being 
passed  through  the  manufacturing  processes  without  being 
submitted  to  the  preliminary  washing  usual  with  wild  rubbers. 
Of  course  the  washing  of  sheet  rubber  is  only  a  perfunctory 
process  and  affects  merely  the  surface.  Furthermore,  the  passing 
of  large  lumps  of  coagulated  rubber  through  washing  rollers  converts 
the  product  into  a  shape  in  which  it  can  be  easily  handled  in  far 
less  time  than  when  separate  trays  are  used  for  each  sheet  or 
biscuit  of  rubber.  The  fact  that  by  the  use  of  washing  machines 
on  plantations  the  planter  is  able  to  successfully  deal  with  his 
large  crop,  is  probably  quite  as  important,  to  him,  as  the  purifica- 
tion effected  in  the  rubber. 

Removal   of   Acids   by   Washing. 
An   important   reason    for   thoroughly   washing   the    rubber 
immediately  after  coagulation  is  that  the  residual  acid  is  harmful. 


PARA     RUBBER  355 

to  the  rubber,  and  interferes  with  vulcanization,  and  must  therefore 
be -removed  as  far  as  is  possible.  Some  of  the  acid  remains 
adsorbed  on  the  surface  of  the  caoutchouc  globule,  and  experience 
has  shown  that  it  is  impossible  to  remove  such  adsorbed  acid  by 
mere  washing.  But  it  is  desirable  that  the  quantity  of  acid 
retained  should  be  small,  for,  as  Spence  shows  in  the  case  of 
sulphuric,  the  residual  acid  is  harmful  to  the  rubber  and  may 
induce  tackiness.  Brindejonc  has  demonstrated  the  evil  effects  of 
acetic  acid  upon  the  keeping  qualities  of  rubber.  Crossley  has 
shown  that  the  quantity  of  acetic  remaining  in  the  clot  is  small        ,  1 

Another  good  reason  for  washing  is  the  removal  of  all  soluble 
substances  that  may  serve  as  food  for  bacteria  and  moulds. 

Further,  it  has  been  found  that  sheets  and  biscuits,  which  are 
not  really  washed,  have  a  tendency  to  deposit  on  the  rollers  of  the 
mixing  machine  a  sticky  substance  that  causes  the  mineral  matter 
of  the  compound  to  adhere  and  form  hard  scales  or  flakes. 

Mr.  P.  M.  Matthew,  of  the  Victoria  Rubber  Company,  Edin- 
burgh, suggested  that  immediately  after  coagulation  the  rubber 
should  be  thoroughly  cleansed  by  maceration  in  pure  water. 

Washing  Machines  for  Plantations. 

Less  than  ten  years  ago  washing  mills  were  hardly  known 
on  Eastern  plantations.  I  understand  that  the  introduction  of 
washing  machines  was  largely  the  result  of  conferences  between 
Mr.  Tarbet  (late  Editor,  India- Rubber  Journal),  Mr.  P.  J.  Burgess, 
at  that  time  attached  to  the  Agricultural  Department,  F.M.S.,. 
and  Mr.  Francis  Pears,  then  Manager  of  I.anadron  Estate,  Johore.^ 
Burgess,  at  an  agricultural  conference  in  Malay,  about  seven 
years  ago,  read  a  paper  to  planters  in  which  he  outlined  the  main 
features  of  washing  mills  he  had  seen  working  in  England ;  he 
definitely  advised  their  use  on  plantations.  Very  soon  Ceylon 
and  Kuala  Lumpur  firms  advertised  washing  machines  supplied 
with  rollers  of  quite  a  miniature  type,  but  fitted  with  feeding 
troughs  and  gears  of  an  enormous  size ;  since  that  date. 
Eastern  engineers  have  much  improved  their  machines.  British 
and  Continental  firms  have  also  entered  the  market,  and  have 
entirely  changed  the  mechanical  features  of  this  department 
of  factory  work  on  estates. 

Types  of  Plantation  Washing  Machines. 

Washing  machines  on  plantations  are  constructed  on  the 
same  principles  as  those  for  factories  in  Europe.  The  main 
difference  is  in  the  sizes  of  the  rollers  and  component  parts, 
and,  therefore,  in  capacity.  Some  countries  have  not  yet  adopted 
washing  mills  and  a  brief  description  of  their  construction  and 
working  is  therefore  necessary. 

A  typical  machine  consists  essentially  of  two  chilled  cast-iron 
or  steel  rollers,  which  revolve  on  horizontal  axes  parallel  to  one 
another.  The  distance  between  the  surfaces  of  the  two  rollers  can 
be  adjusted,  and  varies  from  about   one  inch   to   contact.     The 


356  PARA     RUBBER 

adjustment  is  effected  by  turning  a  screw  at  each  end  of  the  roller 
or  at  one  end  only.  The  fittings  of  the  roUers  are  so  arranged 
that,  in  the  event  of  large  stones  being  introduced  between  them, 
either  the  fittings  readily  give  way  or  the  rollers  stop.  Safety 
bushes,  the  screws  of  which  break  if  any  stones  get  between  the 
rollers,  are  usually  supplied.  The  rollers  may  revolve  at  the 
same  or  different  speeds.  The  axes  of  the  two  rollers  may  be 
on  the  same  horizontal  plane  ;  more  usually,  the  back  roller  is 
slightly  above  the  other.  A  stream  of  hot  or  cold  water  flows 
over  the  surface  of  the  rollers  all  the  time  they  are  in  use. 

Fresh  soft  rubber  is  placed  between  the  rollers,  and  is  passed 
through  them  several  times,  the  rollers  being  brought  close  together 
until  the  strip  of  sheet  or  crepe  is  even  in  thickness  and  compara- 
tively hard.  If  scrap  or  bark  rubber  is  used,  and  the  rollers 
are  running  at  different  speeds,  pieces  of  bark,  wood  and  dirt  are 
ejected  as  a  result  of  the  stretching  and  tearing  to  which  the  mass 
is  subjected.  The  stream  of  water,  supplied  from  a  jet  immediately 
above  the  middle  of  the  roUers,  thoroughly  washes  away  any 
mechanical  and  readily  soluble  impurities  in  the  rubber. 

Each  machine  is  usually  provided  with  a  trough  into  which 
the  soft  or  scrap  rubber  is  fed  ;  below  is  a  perforated  tray  to  catch 
fragments  of  rubber  and  yet  allow  water  and  finely  pulverised 
impurities  to  escape. 

It  is,  therefore,  obvious  that,  apart  from  the  fact  that  the 
machines  enable  the  planter  to  deal  rapidly  with  large  quantities 
of  rubber,  their  use  also  ensures  the  removal  of  mechanical  im- 
purities, the  washing  of  all  parts  of  the  rubber  by  clean  water, 
and  the  production  of  a  thin  sheet  of  fairly  uniform  thickness 
and  length  convenient  for  subsequent  drying  and  packing. 

Types  of  Machines   Required   by   Planters. 
There  are  usually  three  types  of  machines  required  by  planters, 
which  are  conveniently  described  as  sheeting,  creping  and  macerat- 
ing mills. 

Sheeting  Machines. 

Sheeting  inachines  are  supplied  with  perfectly  smooth  rollers 
which  revolve  at  nearly  even  speeds,  the  differential  speed  usually 
being  only  one  tooth  difference.  The  rubber  is  therefore  not 
subjected  to  much  tearing  or  stretching,  and  is  not  washed, 
internally,  to  the  same  degree  as  crepe.  These  machines  are 
used  for  making  sheet  rubber  and  for  binding  rubber  which  has 
been  repeatedly  passed  through  creping  or  macerating  machines. 
Sheet  rubber  can  be  more  easily  impressed  with  an  estate  mark 
than  crepe. 

Creping  Machines. 

Creping   machines   are   suppUed   with   grooved   rollers,   the 

flutings  or  grooves  sometimes  being  horizontal,  at  other  times 

square  or  diamond-cut  and  sometimes  spiral.     On  some  estates 

these  machines  are  supplied  with  one  roller  smooth  and  the  other 


BRIDGE'S    BELT-DRIVEN     WASHING     MACHINE. 


ROBINSON'S    WASHING    MACHINE. 


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PARA     RUBBER  357 

grooved.  The  rollers  run  at  uneven  speeds,  5  to  4  and  3  to  2 
being  common  speed  ratios  ;  on  some  properties  a  much  higher 
differential  rate  of  revolution  is  preferred.  It  is  obvious  that 
rubber  prepared  in  a  creping  machine  is  better  washed  and  gener- 
ally subjected  to  far  more  stretching  and  tearing  than  that  prepared 
between  even-speed  sheeting  rollers.  This  difference  is  so  great, 
and  the  effect  on  the  rubber  so  pronounced,  that  many  manu- 
facturers have  cautioned  estate  managers  against  their  use,, 
It  is,  however,  possible  to  achieve  the  desired  results  without 
risking  deterioration  of  the  rubber.  This  is  being  done  successfully 
on  many  estates. 

Creping  machines  are  used  primarily  for  the  production  of 
long  strips  of  crepe  rubber  which  can  be  rapidly  dried.  They 
are  also  occasionally  used  for  macerating  bark  shavings  and  wash- 
ing scrap. 

The  grooves  in  the  rollers  vary  in  distance  from  each  other 
according  to  the  pattern  adopted,  and  also  in  depth  and  width. 
The  groovings  give  a  definite  appearance  or  pattern  to  the  crepe, 
which  sometimes  makes  the  impressing  of  an  estate  mark  difficult 
on  this  class  of  rubber. 

Bertram's,  Ltd.,  state  that  they  have  supplied  single  spiral 
even-speed  machines  for  finishing  purposes,  having  the  grooves 
in  the  same  direction  so  that  they  cross  at  the  nip  of  the  rolls, 
thereby  marking  the  rubber  so  as  to  form  a  diamond  pattern 
when  held  up  to  the  light.  If  the  machine  used  for  this  purpose 
is  supplied  with  double  spirals  it  is  found  that  the  diamond  im- 
pression on  the  one  side  of  the  rubber  shows  on  the  opposite  side 
and  thereby  gives  a  confused  impression  instead  of  a  clear  diamond 
as  given  by  the  single  spiral  roll. 

Macerating  Machines. 

These  generally  differ  from  creping  machines  in  having 
roller ;  set  at  a  greater  differential  rate  of  revolution,  a  speed  ratio 
of  3  to  2  and  2  to  i  being  adopted  on  some  estates.  The  machines 
are  used  primarily  for  tearing  and  stretching  bark  shavings  and 
scrap  rubber.  They  are  also  used  for  shaping  freshly-coagulated 
rubber  before  passing  it  through  creping  or  sheeting  rollers,  one 
rolling  usually  being  sufficient  for  this  purpose.  It  is  advisable 
that  one  macerating  machine  shall  be  set  apart  for  dealing  with 
dirty  rubber  and  scrap,  in  order  to  avoid  contamination  of  the 
purer  grades.  Even  then  it  is  necessary  to  clean  the  machines 
more  frequently  than  the  others  if  the  best  results  are  to  be  ob- 
tained. The  groovings  are  usually  spiral  or  zigzag,  and  are  deeper 
and  wider  than  those  on  creping  rollers.  It  is  usually  necessary 
to  immediately  pass  the  rubber,  when  freed  from  all  impurities, 
through  smooth  sheeting  rollers,  in  order  to  get  the  benefit  of  any 
binding  effect  which  such  treatment  may  afford;  frequently 
the  rubber  when  finished  in  the  macerating  machine  is  in  such  a 
state  that  re-binding  is  impossible  or  extremely  difficult. 


58  PARA     RUBBER. 

Sizes  and  Chilling  of  Rollers. 
The  first  washing  machines  used  on  plantations  were  com- 
paratively small— rollers  8  to  9  inches  long— but  there  is  now  a 
pronounced  tendency  to  adopt  sizes  somewhat  similar  to  those 
used  in  Europe.  For  small  estates  rollers  18  in.  long  by  gj  in. 
diameter,  and  for  large  estates  18  in.  by  12  in.  are  now  usually 
recommended.  The  common  stock  sizes  for  plantations  are 
6  by  12,  7  by  12,  9  by  18,  gi  by  18,  12  by  15,  12  by  18,  14  by  21 
and  16  by  28  inches,  the  smaller  figure  being  the  diameter.  Most 
firms  supply  chilled  cast-iron  rollers,  as  it  is  believed  that 
these  last  longer  than  those  not  chilled.  They  are  not,  as  many 
planters  seem  to  think,  rust-proof.  The  deepening  or  re-cutting 
of  the  grooves  when  worn  down  is  by  no  means  an  easy  task. 
Chilling  increases  the  durability  of  the  rollers,  and  the  grooves 
are  not,  Iherefore,  worn  as  speedily  as  they  would  otherwise  be  ; 
but  it  is  being  doubted  in  many  quarters  whether  <  hilling  really 
pays.  Rollers  for  sheeting  machines,  made  of  hard, close-grained, 
cast  iron  are  said  to  be  quite  good.  Cochrane's  supply  rollers 
which  are  said  to  be  hard  and  non-rusting.  The  rollers  for 
plantation  machines  are  generally  solid ;  Warner's  recently 
made  hollow  rollers  for  plantations  which  could  be  heated  in 
order  that  softening  prior  to  blocking  could  be  effected. 

Speed  of  Rollers. 

As  previously  indicated,  the  speed  of  the  rollers  varies 
according  to  the  tj'pe  of  machine,  sheeting  machines  running 
at  almost  even  speeds  and  macerating  machines  at  the  maximum 
difference.  Bridge's  are  of  the  opinion  that  the  most  economical 
speed  of  rollers  in  macerating,  creping  and  sheeting  machines 
for  newly-coagulated  rubber  is  60  feet  per  minute,  though  they 
have  run  machinery  at  higher  and  lower  speeds.  At  a  higher 
speed,  the  machine  is  running  too  fast  for  the  attendant.  When 
hard  rubber  is  being  rolled,  40  feet  per  minute  is  advisable.  They 
also  find  that  if  the  rollers  are  running  at  the  ratio  of  i  J  to  I,  and 
even  up  to  2  to  i  for  macerating,  4-teeth  friction  for  creping,  and 
I  tooth-friction  for  sheeting  machines,  satisfactory  results  are 
obtained. 

Bertram's,  Ltd  ,  also  advise  a  surface  speed  for  rollers  of  60 
feet  per  minu'e  for  all  machines  on  plantations  They  adopt 
the  following  frictions  :  macerating  machines,  6  to  9  ;  creping 
machines,  6  to  7  or  6  to  8  ;  and  even-speed  for  sheeting  machines, 
6  to  6.  The  rollers  are  usually  run  at  a  speed  of  about  20  revolu- 
tions per  minute. 

Cochrane's  inform  me  that  in  all  their  machines  the  back 
rollers  run  at  24  revolutions  when  9  in.  in  diameter,  and  at  18J 
revolutions  per  minute  when  12  in.  in  diameter.  The  front  rollers 
revolve  in  macerating  machines  at  18  to  23  per  minute  when  9  in. 
diameter,  and  15  to  18  revolutions  per  minute  when  12  in.  diameter 
rollers  are  used.  In  creping  and  sheeting  machines  with  rollers 
9  in.  in  diameter,  they  run  at  20  to  23  and  20  to  24  respectively. 


PARA     RUBBER  359 

Shaw's,  as  well  as  other  firms,  have  the  rollers  running  at 
different  rates  according  to  size.  Rollers  18  by  9J  in.  have  the 
back  rollers  running  at  24  revolutions  per  minute,  the  front  rollers 
running  at  19  (for  macerating),  21J  (for  creping),  and  24  (for 
sheeting)  revolutions  per  minute.  With  rollers  18  in.  by  12  in., 
the  back  roller  is  run  at  20  revolutions  per  minute,  the  front 
running  at  16  (for  macerating),  18  (for  creping),  and  20  (for 
sheeting)  revolutions  per  minute. 

Dimensions  of  Grooves. 

The  depth,  width,  and  distance  apart  of  the  grooves  vary 
according  to  the  pattern  of  flutings  selected.  The  grooves  are 
generally  nearest  to  each  other  in  diamond-cut  rollers,  and  at  the 
greatest  distance,  when  disposed  horizontally ;  it  is  probably 
on  account  of  this  that  diamond-cut  rollers  wear  out  sooner  than 
other  types. 

Various  firms  appear  to  adopt  different  dimensions.  Ber- 
tram's, Ltd.,  make  macerating  rollers  with  grooves  -j^  in.  wide,  by 
J  in. deep,  or  |  in.  wide  by  J  in.  deep  ;  for  creping  the  grooves  ar^ 
I  in.  wide  by  |  in.  deep,  or  |-  in.  wide  by  ^V  in.  deep. 

Bridge's  prefer  grooves  on  spiral  macerating  rollers  to  be 
V-shaped,  fV  in.  wide,  ^A  in.  deep,  and  |  in.  pitch ;  on  the 
coarse  diamond  cuts  the  size  of  the  diamond  is  1^  in.  by  |  in.  with 
sizes  of  grooves  as  above.  Grooves  on  creping  rollers  are  made 
in  diamond-pattern  V-shapes,  -fy  in.  wide,  iJV  in.  deep,  and  the 
sizes  of  the  diamond  f  in.  and  |  in.  Straight-cut  rollers,  for 
macerating  or  creping,  are  made  with  grooves  |  in.  pitch,  ^V  in. 
by  J  wide  and  V-shaped. 

Cochrane's  make  their  spiral,  horizontal  and  diamond  grooves 
on  macerating  and  creping  rollers  f\;  in.  wide  with  a  pitch 
varying  from  ;^  in.  to  I  in.,  and  the  depth  from  ,Vr  in.  to -^  in.  In 
diamond-cut  rollers  the  grooves  are  jV  in.  deep,  J  in.  wide,  and 
from  f  in.  to  f  in.  pitch. 

Robinson's  make  the  grooves  in  all  fluted  rollers  of  definite 
dimensions,  but  vary  the  latter  according  to  the  size  of  the  rollers. 
The  grooves  are  -jJ,;  in.  deep,  y\>  in.  wide,  and  have  a  pitch 
off  in.  for  rollers  4  in.  by  6in.  and  6in.  byioin.  The  depth  is  Jin., 
width  T^l  in.,  and  pitch  |  in.,  for  rollers  8  in.  by  12  in.,  or  12  in. 
by  16  in.,  and  I'Vin.  deep,  yV  in.  wide,  and  pitch  J  in.,  when 
rollers  are  14  in.  by  26  in. 

Shaw's  make  the  grooves  in  spiral  and  diamond  patterns, 
on  macerating  rollers  with  i  in.  pitch,  the  depth  in  the  former 
being  ^\  in.  and  width  J  in.,  while  the  depth  in  the  latter  is  J  in. 
and  width  /^  in.  For  creping  machines,  diamond-pattern,  the 
grooves  are  ^l  in.  deep  and  wide  and  J  in.  apart.  In  their 
sheeting-machines  the  horizontal  grooves  are  g^j  in.  deep,  tV  in. 
wide,  and  |  in.  apart. 

Hand-Power  Washing  Machines. 

On  estates  which  are  only  commencing  tapping  operations, 
it  is  not  usually  deemed  advisable  to  go  to  the  expense  of  erecting 


36o  PARA     RUBBER. 

the  heavy  types  of  washing  machines  mentioned  in  the  foregoing 
pages.  An  ordinary  wooden  mangle  has  been  used  on  many 
estates  having  monthly  crops  of  a  few  hundred  pounds.  Where 
the  monthly  crop  is  larger  than  this,  wooden  rollers  are  soon 
worn  out,  and  it  is  usual  to  replace  them  with  metal.  The  hand- 
power  washers  now  being  sent  to  the  East  are  supplied  with 
metal  rollers,  and  can  be  worked  by  two  coolies  each  turning 
a  handle.  These  mangles  are  also  supplied  with  a  pulley  in 
order  that  at  a  later  date  they  can  be  driven  by  belt. 

In  the  hand-power  washing  machine  turned  out  by  Shaw's, 
the  rollers  can  be  altered  from  the  horizontal  position  for  washing 
to  the  vertical  for  rolling  sheets  and  biscuits,  and  they  may  be  run 
at  even  or  at  friction  speeds. 

Machines  for  Bark  Shavings  and  Scrap. 

Bark  shavings  are  usually  mixed  with  varying  quantities 
of  scrap  rubber,  and,  in  addition,  contain  rubber  which  has 
coagulated  internally.  To  macerate  the  bark  tissues  and  enable 
the  operator  to  effectively  separate  the  rubber  therefrom,  macerat- 
ing machines  are  employed.  The  bark  shavings  are  usually 
first  steeped  in  tubs  or  tanks  of  water  for  several  days  in  order 
to  soften  the  tissues  ;  the  bark  may,  perhaps  advantageously, 
be  more  rapidly  destroyed  by  the  use  of  small  quantities  of  caustic 
alkalies.  Before  rubber  can  be  effectively  separated  from  the 
shavings,  it  is  generally  necessary  to  pass  the  whole  mass  through 
the  rollers  many  times.  The  rubber  finally  obtained  from  bark 
shavings  is  generally  dark  in  colour,  and  even  though  it  may 
have  been  well  washed,  has  a  tendency  to  become  sticky  on  the 
surface.  Smoking  the  rubber  over  a  wood  fire  is  an  improvement 
which  is  more  necessary  with  this  than  with  any  other  kind  of  rubber 
from  plantations. 

The  Valour  and  Guiguet  Machines. 

Comparatively  little  attention  has  been  paid  to  the  pro- 
vision of  special  machines  for  dealing  with  bark  shavings.  Usually 
the  shavings  are  accumulated  until  there  is  sufficient  to  justify 
the  using  of  an  ordinary  macerating  machine.  And  certainly 
the  quantity  of  bark  parings  requiring  treatment  on  all  except 
the  largest  estates  scarcely  justifies  any  considerable  capital 
expenditure  upon  special  machinery.  One  of  the  simplest  of  these 
machines  is  the  "Valour,"  a  drum  revolving  on  a  horizontal  axis, 
and  containing  a  number  of  loose  heavy  metal  bars  that  crush 
the  bark  to  fine  particles. 

A  more  elaborate  machine  is  the  "Guiguet."  In  this  the 
bark  is  reduced  to  a  paste  between  a  fixed  and  a  rotating  plate, 
each  provided  with  teeth.  The  paste  passes  to  agglomerators, 
which  consist  of  cones,  with  helicoidal  grooves,  revolving  in 
sleeves  with  grooves  of  opposite  sign,  a  current  of  water  carrying 
bark  away,  and  the  rubber  collecting  into  masses.  These 
masses  are  carried  into  a  revolving  drum,  in  which  there  is  further 
separation  of  bark,  and  are  then  treated  in  a  second  agglomeratcr. 


PARA     RUBBER 
A  New  Type  of  Washing  Machine. 


361 


The  ' '  Universal  ' '  rubber  washer,  made  by  Messrs.  Werner, 
Pfleiderer  and  Perkins,  has  been  designed  mainly  to  avoid  injuring 
the  nerve  of  rubber  by  too  severe  a  mechanical  working.  Objec- 
tions to  the  ordinary  type  of  macerating,  machine  are  that  the 
force  of  the  rollers  is  concentrated  upon  a  narrow  strip  of  the 
rubber  to  its  detriment  ;    that  the  crushing  and  splintering  action 


A'A'^,  rolls;  B ' B '^ ,  their  bearings  ;  C,  trough;  D,  ledges  in  C;  E,  gratings; 
F.  sliding  frames  in  C;  G,  jacket  of  C;  H'H-',  \alves  in  G;  I.',  outlets; 
J' J'-',  levers  for  valves  ;  K'K',  slots;  L'L-,  shakers  in  slots  ;  M'M'^,  ledges; 
K'N",  saddles  for  opening  out  rubber;  O,  sand  box;  P'P'', flaps  for  flushing 
out  O ;  Q,  outlet  for  draining  O ;  R,  packing ;  S,  straining  vessel  to  catch 
impurities;  T',T'^,  sieves  in  S ;  U,  outlet  to  S;  V,  spray  pipe. 

upon  contained  sand  and  bark  hinders  the  purification,  for  the 
particles  become  embedded  in  the  rubber  and  are  difficult  to 
remove,  so  that  prolonged  washing  is  necessary  ;  that  the  quantity 


362  PARA     RUBBER 

of  rubber  that  can  be  manipulated  is  small,  as  it  is  limited  to 
what  the  operator  can  handle  ;  and  that  the  loose  scrap  needs 
constant  shovelling  up  from  the    ray  below. 

In  the  "Universal"  washer,  two  very  deeply  corrugated 
rollers — the  ridges  large  and  wide  apart,  and  of  a  zigzag  pattern — 
revolve  in  a  double-walled  trough,  above  which  is  a  spray-pipe. 
The  rollers  are  not  set  close  together,  and  are  carried  in  fixed 
bearings  instead  of  adjustable  ones,  as  is  usually  the  case,  and  this, 
with  the  deepness  of  the  grooves  between  the  ridges,  prevents 
undue  compression  of  the  rubber  while  it  is  being  opened  out  under 
water  and  the  impurities  rejected.  The  bottom  of  the  trough  is  in 
the  form  of  two  semi-cylinders  in  each  of  which  is  one  of  the 
rollers,  a  space  being  left  between  the  rollers  and  the  trough. 

On  account  of  the  peculiar  formation  of  the  rollers,  the 
rubber,  as  it  is  fed  in,  is  immediately  gripped  and  carried  down- 
wards between  them,  being  opened  out  at  the  same  time,  and 
passes  next  between  the  rollers  and  trough  bottom,  where,  owing 
to  the  formation  of  the  bottom,  the  opening  out  is  continued, 
the  rubber  being  automatically  brought  to  the  surface  again. 
Guides  are  provided  to  turn  the  rubber  towards  the  centre  again 
as  it  comes  to  the  top,  and  in  this  way  it  is  continuously  carried 
round  until  thoroughly  cleansed. 

A  striking  feature  of  the  machine  is  the  provision  made 
for  getting  rid  of  the  impurities.  The  finer  of  the  heavy  impurities 
pass  through  two  slots  beneath  the  rollers  that  are  provided  with 
shakers  into  a  sand-box,  while  the  pebbles,  nails,  etc.,  are  thrust 
over  a  ledge  on  each  side  almost  level  with  the  tops  of  the  rollers. 
In  the  walls  of  the  inner  part  of  the  trough  are  wire-screens  through 
which  may  pass  wash  water  containing  floating  impurities,  rubber 
particles  being  retained.  The  level  of  the  water  may  be  raised  so 
that  wood  and  similar  large  floating  impurities  may  pass  over  the 
ledges  mentioned,  or  it  may  be  raised  level  with  a  gutter  near  the 
top  into  which  they  may  pass.  These  are  only  the  salient  features 
of  the  machine. 

This  machine  can  be  used  for  washing  any  kind  of  rubber, 
including  jelutong,  guttapercha,  and  balata,  in  addition  to  scrap 
and  bark  shavings.  It  can  also  be  used  by  planters  to  free  the 
freshly-coagulated  rubber  from  acid  and  soluble  substances 
which  harbour  bacteria  and  moulds,  and  owing  to  the  large 
output  capacity  of  the  larger  machines,  considerable  economies  in 
space  and  labour  can  be  secured.  Also  the  particularly  gentle 
action  of  this  machine  is  a  big  point  in  its  favour  when  manipulat- 
ing the  rubber  in  this  early  stage,  for  too  great  care  cannot  be 
taken  to  ensure  the  safety  of  the  ' '  nerve ' '  of  the  rubber. 

Large  quantities  of  freshly-coagulated  rubber  are  quickly 
worked  by  this  machine  into  a  convenient  shape  for  handling  and 
putting   through   sheeting   and   creping   machines. 

The  types  being  made  for  plantations  require  from  8  to  lo 
H.P.  ;  large  types  require  up  to  25  H.P.  each,  but  these  deal  with 
up  to  100  lb.  of  rubber  at  a  time. 


PARA     RUBBER  363 

Drives  for  Rubber  Factories. 

Most  up-to-date  factories  in  the  East  are  now  arranging 
for  their  washing-machines  to  be  driven  direct  from  the  main 
engine  by  means  of  gearing,  each  machine  being  put  in  and  out 
of  gear  by  means  of  a  clutch  fitted  to  the  pinion  working  into 
a  spur  wheel  on  the  main-line  shaft.  Belts  are  therefore  dis- 
pensed with,  and  in  this  alone  there  is  a  great  saving. 

When  washing-mills  were  first  used  in  Ceylon,  each  machine 
was  usually  supplied  with  a  loose  and  fast  pulley,  and  was  driven 
by  separate  belts  from  overhead  shafting.  This  was  the  most 
economical  arrangement  and"  necessitated  fewest  alterations  in  the 
factories  then  existing  and  being  worked  in  connection  with 
the  manufacture  of  tea,  coffee,  sugar,  etc. 

At  a  later  date,  the  same  plan  of  belt-driven  machines  was 
followed  even  when  new  rubber  factories  with  sides  of  corrugated 
iron  were  built.  The  expense  necessary  to  strengthen  the  walls 
of  the  factories  and  erect  brackets  was,  however,  found  to  be 
excessive.  Subsequently,  the  machines  were  driven  from  counter- 
shafting  carried  from  brackets  on  the  floors.  This,  however,  was 
soon  found  to  be  inconvenient,  and  to  require  more  space  than 
could  always  be  afforded. 

In  the  direct-gear  methods  now  being  adopted,  the  shaft, 
driven  direct  from  the  engine,  runs  under  or  at  the  back  of  the 
line  of  machines,  and  is  raised  about  15  inches  above  the  floor- 
level.  Preference  is  given  to  shafting  at  the  back  of  the  mills,  on 
account  of  the  gear  being  clear  of  the  operator.  This  system  of 
direct  driving  where  each  machine  is  supplied  with  a  friction- 
clutch  has  many  advantages  apart  from  saving  in  space.  It 
also  permits  of  extensions  being  easily  made  by  fixing  extension- 
shafts  on  either  side  of  the  engine.  The  only  disadvantages 
appear  to  be  the  higher  initial  costs,  and  the  somewhat  complicated 
apparatus  replacing  the  simple  pulley  and  belt  arrangement. 

Driving  Arrangements  in   Recent  Installations. 

The  driving  arrangement  is  sometimes  modified,  as  in  a 
double  machine,  similar  to  that  made  by  Shaw's.  In  this  case 
both  machines  are  driven  by  a  single  belt,  and  only  one  overhead 
pulley  is  required,  each  machine  being  worked  independently  of 
the  other  by  means  of  friction-clutches.  In  a  recent  installation 
of  plant  on  a  Sumatra  estate  (I.R.J.,  Oct.  28th,  1911),  the  line- 
shaft  driving  the  machinery  is  driven  direct  from  the  crank-shaft 
of  the  engines  by  belting,  a  coupling  being  placed  between 
the  two  driving-pulleys  on  the  main-shaft,  so  that  the  machines 
can  be  driven  by  either  of  two  engines  positioned  together  near 
the  centre  of  the  line  of  washing-mills.  To  give  flexibility  of 
drive  each  pulley  is  mounted  on  a  friction-clutch  so  that  the 
engines  can  be  started  before  the  Une-shaft  is  put  in  motion. 

Shaw's  recommend  for  transmitting  power  from  the  engine  to 
the  line-shaft  a  belt-drive  with  a  puUey  mounted  on  a  friction 
clutch,  or  double  helical  machine-cut  gears  fitted  with  a  clutch.  ' 


364 


PARA     RUBBER 


Clutches   and    Gearing. 

Various  types  of  friction -clutches  are  used  on  the  machines- 
turned  out  by  different  firms. 

In  Shaw's  machines  each  mill  is  operated  by  a  Hele-Shaw 
patent  friction-clutch 


ABC 


Hele- Shaw 
Clutch. 

A,  end  cover ;    B,  clutch  case ;    C,  core ;    D,  inner  steel  plates ;    E,  outer 

bronze   plates ;     F,    presser    plates ;     G,    presser    pins ;     H,    presser   box ; 

J,  actuating  ring ;  K,  triggers ;  L,  adjustable  trigger  ring. 


through  double  helical  machine-cut  gearing.  The  Hele-Sha^r 
clutches  (of  which  a  section  is  illustrated)  are  totally  enclosed 
and  are  unaffected  by  the  dirt  inseparable  from  rubber  washing. 
The  friction  plates  run  in  oil,  and  thus  allow  for  easy  adjustment, 
and  a  gradual  taking  up  of  the  load. 

Bertram's,  Ltd.,  iupply  a  simple  friction-clutch,  the  essential 
features  of  which  are  the  facihty  of  adjustment,  and  the  ease 
with  which  the  clutch  can  be  refilled  on  the  spot,  the 
filling  consisting  of  hard  wood  blocks.  In  the  accompanying 
illustration  a  section  is  shown  of  the  clutch  applied  to  a  spur 
wheel ;  the  adjustment  is  made  by  tightening  the  two  nuts  shown 
at  the  right-hand  side  of  the  disc.     (See  page  365). 

Bridge's,  who  many  years  ago  recommended  driving  planta- 
tion machinery  direct  from  the  engines  by  gearing  and  friction- 
clutches  in  order  to  avoid  the  objectionable  slipping  of  belts, 
have  specialised  in  what  they  term  the  Heywood-Bridge 
patent  friction-clutch.  This  clutch  is  operated  by  means  of  two 
right  and  left  hand  screws,  fitted  with  bell  crank  lever,  and  links 
actuated  by  hand  lever  and  shaft,  worked  from  any  position  to 
suit  the  operator.  They  are  lined  with  wood,  iron,  or  special 
quick-grip  frictional  material  that  can   easily  be  renewed  on  the 


PAR  A     RUBBER 


365 


BERTRAM  S    SECTION    FRICTION-CLUTCH. 


F]G,3 


ARRANGED  AS 
SHAFT  COUPUMO 


F1G4 


AS  APPLIEO 
TO  ROPE  PULUEV 


HEYWOOD    AND   BRIDGE  S   FRICTION -CLUTCH. 


366  PARA     RUBBER 

spot.  These  clutches  are  very  tender  in  their  action  when  starting 
machines,  and  can  be  instantly  disconnected  by  the  operator  in 
case  of  accident. 

Cochrane's  supply  in  addition  to  belt-driven  machines, 
others  driven  direct  through  a  claw-clutch  and  moulded  gears, 
and  a  third  type  driven  by  a  friction-clutch  and  double  helical 
gears  with  the  shafting  at  the  back  of  the  mill.  The  gears  are 
put  into  motion  by  an  expanding  type  of  friction-clutch. 

Outturn  of  Rubber  from  Washing  Machines. 

It  is  extremely  difficult  to  get  reliable  statements  regarding 
the  average  working  capacity  of  washing  machines  on  plantations. 
In  most  factories  one  or  more  of  the  mills  are  not  running,  and 
those  being  worked  are  used  for  the  preparation  of  different  forms 
of  rubber  in  the  wet  state.  Hence  the  difficulty  in  estimating 
the  maximum  outturn  of  dry  rubber  per  day  from  any  particular 
machine,  even  when  the  rollers  are  all  of  the  same  size.  Shaw's 
estimate  that  each  machine,  with  rollers  i8  by  12  inches,  can  turn 
out  45  lb.  of  dry  rubber  per  hour,  and  those  with  smaller  rollers, 
18  by  9J  inches,  from  30  to  35  lb.  per  hour.  It  is  well  known  that  a 
much  larger  outturn  can  be  obtained  if  all  the  machines  are  kept 
working  throughout  the  day,  and  especially  is  this  so  if  the  minimum 
time  is  spent  in  finishing  sheet  rubber.  Cochrane's  estimate 
that  with  quick  work  a  washing  mill  should  turn  out  800  lb.  of 
wet  rubber  per  day.  Bertram's,  Ltd.,  estimate  that  machines  with 
rollers  12  by  15  inches  will  turn  out  from  200  to  300  lb.  of  dry 
rubber  per  day  of  ten  hours.  Robinson's  estimate  an  outturn 
of  25  lb.,  50  lb.,  and  100  lb.  of  dry  rubber  per  hour  from  rollers 
8  in.  by  12  in.,  12  in.  by  16  in.,  and  14  in.  by  26  in.  respectively. 
Bridge's  point  out  that  the  outturn  largely  depends  on  the  finish 
given  to  the  rubber,  but  that  an  average  output  of  30,  40,  and 
56  lb.  per  hour  may  be  expected  from  rollers  g  in.,  12  in.,  and 
14  in.  diameter  respectively.  While  these  estimates  of  output 
differ,  it  must  be  understood  that  the  amount  of  rubber  that  can 
be  dealt  with  by  a  machine  is  influenced  by  the  width  of  the  rollers 
and  their  peripheral  speed. 

Power  for  Driving  Machines. 

Various  types  of  engines,  including  steam,  oil  and  suction 
gas,  are  now  used  for  driving  rubber  machinery.  The  power 
required  depends  upon  the  number  of  machines  in  use,  their 
respective  sizes,  and  the  condition  of  the  rubber  dealt  with. 
On  Eastern  estates  it  is  generally  advisable  to  have  several  small- 
power  engines  than  only  one  capable  of  driving  the  whole  of 
the  machinery,  owing  to  the  time  taken  in  effecting  repairs,  the 
general  lack  of  spare  parts  and  competent  engineering  officers. 
A  breakdown  on  a  plantation  many  miles  from  an  engineer  or 
works  would  be  very  serious  if  only  one  engine  were  'installed. 
The  usual  washing-mills  now  in  use  on  estates  each  require  from 


PARA     RUBBER  367 

8  to  12  H.P.,  but  provision  is  often  made  for  the  addition  of  other 
machines  (as  the  crops  increase  in  quantity)  to  be  driven  by  the 
same  engines.  The  engines  are  usually  provided  with  self- 
starters,  the  Government  in  some  countries  insisting  upon  their 
being  supplied  in  all  factories. 

On  one  estate,  supplied  with  three  washing  mills  having 
rollers  12  by  18  inches,  two  engines,  each  of  32  H.P.,  were  supplied, 
the  object  being  to  drive  all  three  machines  with  one  engine 
when  necessary  to  do  so,  or  to  drive  a  total  of  five  washing  machines 
with  both  engines  at  some  future  date.  On  another  property,  with 
three  machines  each  having  rollers  12  by  15  inches,  a  minimum 
of  24  H.P.,  and  a  maximum  of  36  H.P.,  were  found  workable. 
On  a  third  property,  three  washing-mills  with  rollers  15  by  12 
inches  were  run  by  two  oil  engines  each  capable  of  developing 
22  H.P.,  and  therefore  of  driving  two  machines. 

Filter  Beds  and  Presses. 

The  water  supply,  in  respect  of  quantity  and  purity,  is  of 
great  importance  in  the  factory.  Apart  from  the  use  of  water- 
power,  it  is  necessary  to  have  an  ample  supply  of  water  for  cleans- 
ing, tapping,  and  collecting  tools  and  for  thoroughly  washing  all 
rubber  during  the  washing  process.  It  is  known  that  rubber  can 
absorb  a  moderate  quantity  of  acetic  acid  sometimes  used  in 
irregular  quantities.  Furthermore,  rubber  contains  a  fair  pro- 
portion of  putrescible  substances.  It  is,  therefore,  necessary 
that  large  volumes  of  water  be  available,  and  that  these  be  as  pure 
as  possible.  The  use  of  impure  water  has  often  led  to  discolora- 
tion and  tackiness  in  rubber.  Every  means  should  therefore  be 
adopted  to  ensure  a  satisfactory  water  supply.  On  some  estates 
filter-beds  have  been  constructed  through  which  the  water  is 
allowed  to  pass  before  being  transmitted  to  the  factory. 

There  are  several  filter-presses  which  can  also  be  used  for 
this  purpose  ;  some  have  been  constructed  not  only  for  clarifying 
ordinary  water,  but  also  for  affecting  the  same  change  in  dirty 
water  from  the  washing  machines,  so  that  the  same  water  can  be 
used  several  times.  This  is  of  more  than  parsing  importance  to 
planters  in  districts  with  a  limited  water  supply. 

Johnson's  Water  Filter. 

This  apparatus  consists  of  a  number  of  square  cast-iron  plates 
and  distance  frames  or  rings.  The  plates  have  a  facing  on  each 
side  all  round  the  outer  edge.  When  the  plates  and  frames  are 
placed  side  by  side  in  position  and  the  press  tightened  up,  a  feeler 
'i<nTTr  in.  thick  cannot  be  inserted  between  the  joints.  The  flat 
surfaces  of  the  plates  circumscribed  by  the  machined  surface  is 
studded  all  over  by  small  truncated  square  pyramids  evenly 
spaced. 

The  plates  and  frames  have  lugs  at  the  top  and  bottom.  When 
the  plates  and  frames  are  placed  alternately,  there  is  a  series  of 


368 


PARA     RUBBER 


hollow  chambers  between  the  plates.  These  chambers  each  com- 
municate with  the  bottom  passage  by  means  of  a  port  cast  in  each 
distance  frame,  and  from  these  the  dirty  water  enters  each  chamber. 
Each  plate  has  a  corresponding  port  connecting  from  both  sides 
thereof  to  the  top  passage,  and  this  is  the  only  means  of  exit  for  tha 
water  when  forced  into  the  chambers  under  pressure. 

A  filter-cloth  is  placed  over  each  of  the  plates  and  securely 
gripped  between  the  machined  joints  when  the  press  is  tightened 
up  ;  the  water  must  pass  through  the  filter-cloths  in  order  to  reach 
the  outlet  passage.     It  is  by  this  means  entirely  freed  from  all 


RUBBER  HYDRAULIC  JOINT  COLLARS 


FUXRCD  WATER  O) 


Johnson's  water  filter. 

matter  in  suspension,  which  remains  as  a  deposit  upon  the  surface 
of  the  cloths.  As  this  deposit  increases,  due  to  the  accumulation 
of  the  solid  matter  removed  from  the  water,  the  rate  of  filtration 
willfgradually  diminish  and  eventually  cease. 

The  filter-press  must  be  frequently  opened  and  the  cloths 
removed  and  washed,  after  which  they  can  be  replaced  and 
filtration  continued. 


Pumps  and  Piping. 

Even  when  a  factory  has  a  water  supply  close  at  hand,  a  con- 
siderable length  of  piping  for, use  between  boilers,  washing  machines 
and  the  various  storage  tanks  is  required,  and  should  be  kept  in 
stock  on  all  estates.  Where  the  water  is  some  distance  away, 
expenditure  under  this  head  is  increased.  On  many  estates  the 
water  necessary  for  boilers,  cooling  tanks,  and  washing  machines, 
has  to  be  pumped  from  p  distant  place  many  feet  below  the 
level  of  the  factory  site.  Pumps  are  therefore  necessary  for  this 
work.  Double-acting  pumps  capable  of  raising  from  600  to 
10,000  gallons  of  water  per  hour  through  any  height  up  to  150 
feet,  or  single-acting  pumps  for  supplying  from  300  to  1,000  gallons 
per  hour  adapted  for  belt  driving  are  made.  The  water  is  usually 
carried  to  a  tank  upon  a  steel-framed  tower  from  which  it  is  led  to 

the  far+nrv. 


PARA     RUBBER  369 

Hot  and  Cold  Water. 

It  has  been  the  custom  to  use  hot  water  on  many  rubber 
estates  in  the  hope  of  removing  a  larger  proportion  of  chemical 
impurities  and  destroj^ing  those  organisms  responsible  for  darken- 
ing of  rubber  on  keeping.  Its  use  also  helps  to  maintain  the  rubber 
in  a  softer  and  more  workable  condition  during  the  washing 
process.  Quite  recently,  however,  several  firms  have  expressed 
their  objections  to  the  use  of  heated  water  because  they  believe 
it  has  some  bad  effects  on  the  nerve  of  the  rubber. 

It  is  the  custom  to  supply  spray  pipes,  positioned  above  the 
rollers,  with  steam  and  water  valves  in  order  that  water  at  any 
temperature  can  be  used  during  washing. 

The  use  of  hot  water  for  this  purpose  necessitates  the  erection 
of  steam  boilers  or  other  heating  apparatus.  When  these  are 
introduced,  the  further  possibiUty  of  using  the  exhaust  steam  for 
heating  pipes  in  the  curing  room  should  be  considered. 


CHAPTER  XXIV. 

THE  DRYING  OF  RUBBER. 

The  treatment  to  which  freshly-coagulated  rubber  is  sub- 
jected in  the  various  types  of  washing  machines  has  been  described, 
and  we  must  proceed  to  consider  further  processes  through  which 
rubber  has  to  pass  before  it  is  placed  on  the  market.  The  changes 
which  washed  rubber  subsequently  undergoes  are  associated  with 
loss  of  water  and  the  absence  or  presence  of  certain  preservatives ; 
hence  the  necessity  to  consider  the  importance  of  these  and  the 
methods  adopted  in  drying  and  smoking  the  raw  product. 

Water  in  Wild  and  Plantation  Rubber. 

Most  of  the  rubber  exported  from  African  and  American 
ports  contains  a  large  proportion  of  impurities.  E^^en  fine  hard 
Para  and  Lagos  lump  frequently  possess  over  ten  per  cent,  of  water 
alone  on  their  arrival  in  Europe.  Many  of  the  wild  rubbers 
exhibited  in  the  London  saleroom  can,  by  means  of  hand  pressure 
alone,  be  made  to  eject  water  in  considerable  quantities  ;  other 
rubbers  arrive  in  a  comparatively  dry,  though  otherwise  impure, 
state.  This  variation  in  the  moisture  content  naturally  affects 
the  proportion  of  caoutchouc,  the  value  of  the  rubber  to  the 
manufacturer,  and  therefore  the  price  realized.  In  marked 
contrast  to  this  is  the  dry  rubber  received  from  Eastern  plantations. 
This  freedom  from  moisture  and  consequent  constancy  in  com- 
position is  largely  responsible  for  the  agreement  in  average  prices 
realized  for  consignments  of  plantation  rubber  from  innumerable 
estates  in  Sumatra,  Borneo,  Java,  Ceylon,  and  Malaya.  The 
production  of  rubber  free  from  moisture  may  involve  the  erection 
of  machinery  and  necessitate  a  certain  amount  of  delay  in  delivery  ; 
but  this  is  fully  compensated  for  by  the  results  obtained. 

Removal  of  Moisture  from   Plantatk^x   Rubber. 

The  desirability  of  removing  the  water  from  plantation 
rubber  has  been  discussed  in  many  quarters  and  the  subject  raises 
numerous  points  of  interest.  In  the  first  case  it  should  be  remem- 
bered that  the  difference  between  wild  and  plantation  rubbers  is 
not  one  of  moisture  alone  ;  a  series  of  factors  such  as  the  proportion 
of  putrescible  matter  and  its  state  of  preservation,  the  age  of  the 
trees  whence  the  rubber  is  obtained,  etc.,  all  play  a  part  in  giving 
to  wild  rubber  its  general  characteristics. 

Some  time  ago  it  was  suggested  that  the  extra  moisture 
left  in  fine  Para  ' '  smoke-cured ' '  rendered  it  fit  and  strong  enough 
for   all  purposes,   and   accounted   for  its   not  deteriorating  after 


PARA     RUBBER  371 

being  kept  for  any  length  of  time.  To  this  the  Editor  of  the 
"India- Rubber  Journal"  (April  9th,  1906),  replied  "if  this  is  so,  why 
do  the  manufacturers,  as  soon  as  possible  after  there  arrives  in  the 
factory  a  delivery  of  rubber,  put  it  through  the  washing  machine, 
and  prefer  to  stock  it  as  dry  sheet  rather  than  in  the  state  in  which 
it  arrives  ?  The  answer  is  simply  that  thoroughly-washed 
and  dried  rubber  under  suitable  conditions  will  not  deteriorate 
until  after  a  very  long  lapse  of  time.  The  manufacturers'  dried 
rubber  contains  no  moisture  at  all,  and  in  the  old  days  it  used  to  be 
stocked  for  two  or  three  years  before  being  used  for  special  purposes. 
It  cannot  therefore  be  on  account  of  the  lack  of  moisture  that  the 
rubber  deteriorates."  What  is  true  regarding  Para  rubber  from 
wild  Hevea  trees  is  probably  equally  so  for  rubber  from  the  same 
species  under  cultivation. 

Mr.  C.  Devitt  stated,  in  1906,  that ' '  one  of  the  most  important 
points  in  the  packing  of  plantation  rubber  is  to  get  it  absolutely 
dry  and  quite  free  from  surface  moisture  before  shipping,  as  any 
dampness,  even  if  it  is  only  on  a  few  biscuits  or  sheets,  is  likely 
to  ruin  a  whole  easeful.  We  very  often  find  where  moisture  has 
been  left,  the  rubber  has  turned  white  and  decomposition  has 
started,  making  it  unsightly,  weak,  and  evil-smelling."  Past 
experience  in  the  East  has  proved  the  desirability  of  shipping  the 
rubber  in  as  dry  a  condition  as  it  is  possible  to  get  it. 

Effect  of  Moisture  on  Strength  of  Rubber. 

After  giving  the  analyses  of  various  rubbers,  it  is  stated 
in  the  Official  Handbook  to  the  Ceylon  Rubber  Exhibition,  that 
' '  A  careful  study  of  the  figures  shows  how  difficult  it  is  to  form 
deductions  as  to  what  gives  actual  strength  in  the  rubber,  for  the 
strongest  rubbers  have  not  necessarily  the  most  caoutchouc,  though 
the  difference  of  i  per  cent.,  in  such  high  numbers  as  93  to  95  per 
cent,  would  have  very  slight  effect. ' ' 

It  was  further  stated  that  :  ' '  The  theory  that  more  moisture 
left  in  the  rubber  would  add  to  its  strength  is  apparently  not 
borne  out  by  the  above  figures. ' '  In  view  of  this  statement  it  is. 
difficult  to  understand  the  claims  subsequently  made  by  the 
authors  of  the  above  in  connection  with  the  preparation  of  wet 
creosoted  rubber  described  below. 

Reduction  of  Moisture  and  Increased  Strength. 

Schidrowitz  and  Kaye,  in  their  paper  (I.R.J.,  Sept.  23rd, 
1907)  on  "The  Influence  of  the  Method  of  Coagulation  on  the 
Physical  and  Chemical  properties  of  Funtumia  elastica,"  point  out 
that  as  might  have  been  expected,  the  method  of  coagulation  has 
an  important  bearing  on  the  chemical  and  physical  properties  of 
Funtumia.  It  is  worthy  of  note  that  the  reduction  in  moisture 
from,'  in  the  highest  case,  12-64  to  a  mere  trace  results  in  every 
instance  in  an  appreciable  increase  in  tensile  strength  and  dis- 
tensibility.  This  is  of  particular  interest  in  view  of  the  fact  that 
fine  hard  Para  contains  considerably  more  moisture  than  any  of 


372  PARA     RUBBER 

these  moist  samples.  It  is  probable  that  in  this  moist  Funtumia 
the  water  is  present  in  a  quasi-molecular  state  whereas  in  fine 
hard  Para  it  is  merely  mechanically  admixed.  The  dry  samples 
gave  in  some  cases  very  high  figures  for  the  physical  tests.  It  has 
been  sometimes  asserted  that  to  dry  rubber  too  much  makes  it 
harsh  and  brittle.  These  results  show  that  if  this  is  so,  it  is  not 
due  to  the  removal  of  the  moisture,  but  to  the  manner  in  which  it 
is  removed. 

The  extent  to  which  moisture  should  be  removed  must  depend 
on  the  class  of  rubber  being  treated  and  the  method  of  coagulation. 
It  does  not  necessarily  follow  that  rubber  which  is  packed  some- 
what moist  will  on  arrival  and  after  washing  and  drying  give  worse 
results  than  material  which  is  shipped  very  dry.  It  depends 
largely  on  whether  the  conditions  of  preparation  of  the  crude 
rubber  are  such  that  an  appreciable  quantity  of  moisture  is 
■dangerous  as  regards  mould  formation  or  not.  The  same  remarks 
apply,  in  the  main,  to  plantation  rubber  from  Hevea  trees.  On 
■chemical  and  physical  grounds  there  is,  therefore,  no  reason  why 
anyone  should  recommend  planters  to  ship  their  rubber  in 
the  wet  state  ;  it  should  be  easily  possible  to  improve  upon  the 
native  methods  in  Brazil. 

Water  in,  and  Price  of.  Rubber. 

There  is  also  the  ordinary  commercial  aspect  of  the  case  to 
be  borne  in  mind. 

It  is  obvious  that  when  rubber  varies  in  its  water  content 
the  price  paid  for  the  crude  material  will  also  vary,  and  only  when 
the  rubber  is  free  from  all  impurities  and  of  relatively  constant 
composition  will  the  price  be  at  all  constant.  It  is  the  habit 
of  some  buyers  of  crude  rubber  to  test  the  samples  for  their  water 
and  grit  by  hand  only,  though  no  one  doubts  the  impossibilty 
of  thus  accurately  estimating  the  percentage  of  moisture  in  samples 
from  various  sources.  The  loss  in  weight  of  fine  hard  Para  and 
other  wet  grades,  due  to  the  evaporation  of  water,  is  sometimes 
very  great,  especially  when,  during  transit,  the  rubber  has  been 
stored  in  the  hottest  part  of  the  ship.  The  present  prices  for  fine 
hard  Para  and  plantation  Para  are  4s.  4d.  and  4s.  8d.  per  lb. 
respectively  ;  the  former  contains  up  to  20  per  cent,  and  the 
latter  less  than  0-9  per  cent,  of  water,  so  that  the  price  paid  for 
fine  hard  Para  is,  pound  per  pound  of  dry  rubber,  more  than  that 
paid  for  plantation.  The  increased  price  paid  for  fine  Para  may 
be  owing  to  its  superior  qualities  compared  with  that  from  ordin- 
ary plantations  and  its  estabhshed  position  in  the  manufactur- 
ing industry  ;  it  does  not  mean  that  plantation  rubber  is  getting 
a  lower  price  on  account  of  its  not  possessing  water  ;  the  difference 
paid  is  no  reason  why  any  person  should  have  suggested  the  shipping 
of  plantation  rubber  containing  a  higher  proportion  of  water. 

Creosote  and  Wet  Plantation  Rubber. 

At  the  Peradeniya  Gardens  (Circ.  Jan.,  1907),  experiments 
were  carried  out  to  test  the  possibility  of  sendmg  home  undried 


PARA     RUBBER  373 

rubber  preserved  with  the  aid  of  creosote.  Acetic  acid  and  a 
mixture  of  creosote  in  methylated  spirit  were  added  to  the  latex  ; 
as  soon  as  coagulation  was  complete,  the  mass  was  cut  up  and 
washed,  and  then  blocked  for  two  or  three  hours  in  a  wooden 
mould  in  a  screw  press.  The  block  so  prepared  contained  from  8 
to  9  per  cent,  of  water,  but  the  authorities  thought  that  this 
might  be  reduced  to  7  per  cent,  if  necessary. 

Samples  prepared  in  the  above  manner  were  valued  at  5s.  6d. 
per  lb.  It  was  thereupon  pointed  out  that  as  ordinary  Ceylon 
plantation  rubber  contains  less  than  i  per  cent,  of  moisture,  the 
price  obtained  for  the  experimental  samples  was  equivalent  to 
6s.  a  pound  for  the  actual  rubber  they  contained.  The  actual 
sales  on  the  same  day  were  ' '  CuUoden ' '  5s.  gjd.  and  on  seven 
other  estates  5s.  y^d.  The  rubber  therefore  obtained  a  price  3d. 
better  than  the  exceptionally  good  lot  sent  from  Culloden  ;  this 
compared  very  favourably  indeed  with  any  previously  reahzed, 
thougji  it  was  not  up  to  that  of  fine  hard  Para.  It  was  not, 
apparently,  known  to  the  experimentalists  that  later  con- 
signments proved  to  be  unsaleable,  and  that  their  appearance 
on  the  market  was  strongly  objected  to. 

The  following  analyses  were  given  to  show  the  composition  of 
the  wet  rubber  after  drying  ten  days,  and  the  average  of  good 
Ceylon  biscuits  : — 

Creosoted  Wet  Rubber.  Average  CeyLon  Biscuit, 

per  cent.  per  cent. 

7-06  .  .  0-45 

o-i8  ..  0-34 

I'92  .  .  2'OI 

3'67  •,  2'37 

87-17  ..  94-83 


Moisture 
Ash  .. 
Resin 
Proteins 
Caoutchouc 


loo-oo 


Nitrogen  0-58  0-37 

Messrs.  Bamber  and  WiUis  concluded  that  planters  were 
removing  too  much  from  their  rubber,  especially  in  the  way  of 
moisture,  and  that  in  future  it  would  be  advisable  to  block  rubber 
in  the  wet  condition,  provided  it  was  rendered  antiseptic  by  the 
use  of  creosote  or  other  preservative.  This  conclusion  was 
quite  unwarranted,  and  in  order  to  test  its  value  the  opinions  of 
leading  manufacturers  were  obtained. 

Manufacturers  Against  Wet  Plantation  Rubber. 

It  will  be  generally  admitted  that  the  users  of  plantation 
rubber  are,  in  virtue  of  their  long  association  with  rubbers  of 
many  kinds,  able  to  exercise  sound  judgment  on  such  a  question. 
The  ' '  India- Rubber  Journal, ' '  in  the  issue  dated  September 
23rd,  1907,  gave  the  following  account  of  the  opinions  of  manu- 
facturers on  plantation  rubber  in  the  wet  and  dry  state. 

The  question  put  before  the  manufacturers  was  whether 
they  preferred  to  receive  plantation  rubber  in  the  pure  and  dry 
state   or  with  water  and  creosote.     If   manufacturers   will   pay 


374  PARA     RUBBER 

a  price  for  wet  plantation  rubber  which  will  give  the  planter  a 
return  equal  to  or  better  than  that  realized  for  the  dry  material 
it  will  be  a  great  advantage,  and  will  allow  the  producers  to  turn 
out  their  rubber  in  the  minimum  time. 

The  following  are  the  repUes  of  several  firms  in  reply  to  the 
question  given  above  : — ' '  Dry  state  "  j  "  Pure  and  dry  "  ;  "  Pure 
and  dry  state  "  ;  "  Pure  and  dry  state  most  decidedly. ' '  This 
unanimity  among  manufacturers  using  the  rubber  for  entirely 
different  purposes  came  as  a  surprise.  Not  a  single  firm  repUed  to 
the  effect  that  they  preferred  the  rubber  in  the  ' '  wet  and  creosoted 
condition  ;  they  plumped  for  the  ' '  dry  and  pure  state. ' '  If  only 
planters  in  the  East  will  realize  how  important  it  is  that  their 
rubber  is  always  at  the  top  for  price,  purity,  and  constancy,  even  if 
the  maintenance  of  that  reputation  necessitates  what,  for  the 
present,  appears  almost  unnecessary  expenditure,  they  wiU  be 
well  advised.  The  cheapening  of  the  processes  of  production  does 
not  tempt  those  proprietors  who  know  the  value  of  keeping  their 
product  in  the  front  rank  in  every  respect  ;  it  is  hoped  that  no 
recommendations  will  be  again  issued  until  the  opinions  of  manu- 
facturers have  been  secured  on  the  samples  submitted. 

Since  the  above  experiments  were  made  no  one  has  seriously 
attempted  to  ship  rubber  in  the  wet  state.  In  fact,  competition 
has  been  exceptionally  keen  among  planters  and  engineers  in  the 
improvement  of  methods  of  dr5dng  the  raw  product,  and  numerous 
inventions  and  systems  of  drying  are  now  being  tried  throughout 
the  middle  East.  It  is  with  these  methods  of  drjdng  that  we 
must  now  concern  ourselves. 

Methods  of  Drying  ix  the  East. 

There  are  four  methods  of  very  unequal  merit  by  which 
rubber  is  dried  on  plantations  in  the  East  :  (i)  Exposure  in  the 
open  ;  (2)  Dr3ring  indoors  in  currents  of  unheated  air  ;  (3)  Drying 
indoors  in  heated  air  ;  and  (4)  Drying  in  vacuum.  All  except  the 
first  involve  the  erection  of  commodious  factories,  with  which  it 
will  therefore  be  necessary  to  deal  in  this  chapter. 

Exposure  in  the  Open. 

This  is  a  method  that  does  not  require  any  machinery,  but 
it  is  one  which  cannot  be  recommended  on  account  of  the  liability 
of  the  rubber  to  turn  soft  and  sticky  on  exposure  to  the  sun. 
It  is  only  practised  by  native  owners  of  very  smedl  plantations. 

CoLD-AiR  Currents. 

The  second  method  is  that  of  drying  the  rubber  in  dark 
rooms  kept  at  ordinary  temperatures.  The  length  of  time  required 
to  dry  the  rubber  under  such  conditions  is  determined  mainly  by 
the  circulation  of  air  through  the  room  and  the  thickness  of  the 
rubber.  Under  ordinary  conditions,  with  rubber  prepared  in 
thin  sheets  or  crepe  an  interval  of  weeks  or  months  may  be  allowed 


PARA     RUBBER  375 

for  this  process.  This  is  obviously  a  very  slow  method,  though 
it  is  used  by  persons  who  believe  that  a  better  product  is  obtained 
by  allowing  the  rubber  to  dry  very  slowly.  It  is  not  in  the  planter's 
interests  to  thus  keep  the  rubber  in  the  store,  because,  apart  from 
financial  considerations,  it  is  liable,  when  exposed  for  such  a  long 
period  to  become  tacky  or  mouldy. 

It  is,  however,  not  advisable  to  spend  huge  sums  of  money 
or  to  go  to  the  trouble  and  risk  of  erecting  complicated  machinery 
when  estates  are  just  beginning  to  yield.  The  experience  gained 
on  a  small  scale,  even  if  it  is  limited  to  mouldiness  and  tackiness, 
is  of  considerable  value  when  large  crops  are  anticipated.  Managers 
having  about  1,000  lb.  of  rubber  per  month  can  easily  deal  with 
their  produce  in  a  corrugated  iron  factory,  supplied  with  wooden 
reapers,  ij  by  J  in.,  stretching  across  the  width  of  the  building. 
It  is  not  absolutely  necessary  that  a  fan  or  heating  apparatus  be 
provided  ;  it  is,  however,  advisable  to  provide  such  a  chamber 
with  an  ample  supply  of  fresh  air.  Under  these  circumstances  it 
should  be  possible  to  turn  out  dry  rubber  within  a  week  if  the  air 
is  maintained  at  a  little  over  90°  F. — a  by  no  means  unusual 
temperature  for  iron-roofed  buildings  in  the  East.  As  a  matter 
of  fact,  simple  buildings  of  this  type  are  to-day  used  on  estates 
with  very  large  monthly  crops  and  no  serious  difficulties  are 
encountered. 

In  one  type  of  cold-air  factory  the  floor  is  laid  with  open 
joints  to  enable  air  to  pass  through,  and  a  ventilator  is  provided 
in  the  roof  to  ensure  a  continuous  current. 

Burgess  stated  that  it  was  possible  to  dry  rubber  without 
any  artificial  heat,  by  the  use  of  some  agent  that  will  dry  the  air. 
For  this  purpose  he  suggested  calcium  chloride.  This  substance  is 
made  commercially  on  a  large  scale  ;  it  is  comparatively  cheap 
and  very  effective  as  a  drying  agent.  The  material  as  bought  is 
in  white  granular  lumps  which,  when  placed  in  the  open  air,  absorb 
moisture  from  it,  and  the  calcium  chloride  becomes  moist  and 
eventually  absorbs  so  much  water  that  a  syrupy  liquid  results. 
It  can  be  recovered  from  the  wet  state  by  simply  heating  and 
thereby  driving  off  the  moisture.  It  is  not,  however,  used  on 
estates  at  the  present  time. 

HoT-AiR  Rooms. 

The  third  method  is  that  of  using  hot-air  chambers  provided 
with  shelves  or  poles  over  which  to  spread  or  hang  the  rubber. 
The  temperature  is  maintained  at  from  90°  to  100°  F.  by  means 
of  hot  air  which  is  drawn  through  the  building  by  means  of  a  fan. 
The  heating  is  generally  effected  by  hot  air  or  steam  pipes  placed 
around  the  building.  In  one  form  of  drying-shed  the  pipes  run 
below  the  open  floor.  Whenever  artificial  heat  is  resorted  to, 
care  should  be  exercised  and  the  temperature  never  allowed  to 
rise  above  120°  F.,  owing  to  the  adverse  effects  of  high  tempera- 
tures on  rubber.  Weber  asserted  that  certain  brands  of  rubber 
cannot  be  hung  up  to  dry  in  the  form  of  sheets  after  the  washing 


376  PARA     RUBBER 

process,  as  they  become  so  soft  as  to  fall  to  pieces.  The  tem- 
perature at  which  rubber  begins  to  soften  varies  according  to  the 
percentage  of  resinous  and  oily  substances  present ;  many  samples 
of  good  Para  rubber  pass  into  a  more  or  less  fluid  state  at  about 
170°   to  180°  F. 

Hot  air  buildings  are  usually,  but  not  always,  two  storeys 
high,  and  are  fitted  up  with  heating  apparatus  of  a  special  charac- 
ter. The  various  contrivances  adopted  can  best  be  dealt  with 
in  that  section  of  this  chapter  dealing  with  factories.  On  many  tea 
and  cacao  estates  in  Ceylon  the  rubber  is  dried  in  the  withering 
and  curing-sheds  respectively.  Such  an  arrangement  is,  however, 
only  advisable  when  the  rubber  crops  are  insignificant.  When 
the  rubber  is  harvested  in  regular  and  increasing  quantities, 
separate  factories  must  be  built  for  dealing  with  the  crop. 

Factories  on  Plantations. 

It  is,  for  obvious  reasons,  necessary  to  provide  on  estates  with 
large  areas  in  bearing  some  building  wherein  the  rubber  can  be 
protected  during  the  coagulating,  washing,  drying,  smoking,  and 
packing  stages.  The  washing  machines  and  engines,  with  the 
necessary  shafting,  are  usually  of  a  heavy  type  ;  these,  together 
with  driers,  fans,  and  other  appliances,  necessitate  the  construction 
of  buildings  of  a  substantial  and  permanent  character. 

Selection  of  Site. 

The  selection  of  a  suitable  site  requires,  in  some  countries, 
considerable  thought.  On  hilly  estates  it  is  customary  to  select 
some  area  as  low,  while  as  central,  as  possible.  This  generally 
enables  the  manager  to  economise  in  transport  and  sometimes  to 
use  water  power.  On  such  properties  sites  which  are  swampy,  liable 
to  'flood,  or  unhealthy,  should  be  avoided.  It  is  often  much 
cheaper  to  select  a  site  at  some  altitude,  and  pump  water  up  to 
the  factory,  than  to  choose  a  place  convenient  only  for  water  and 
transport.  In  considering  the  site  in  relation  to  transport,  it 
should  be  borne  in  mind  that  carrying  the  latex — which  may 
contain  more  than  50  per  cent,  of  water — to  the  factory  is  more 
expensive  than  the  subsequent  transport  of  dry  rubber  to  the 
nearest  cart  road.  The  selection  of  a  site  is  also  partly  determined 
by  the  accessibiUty  of  the  area  for  passenger  and  cart  trafiic, 
proximity  to  a  good  clean  supply  of  water,  exposure  to  wind,  and 
the  character  of  the  subsoil.  In  Ceylon  and  other  hilly  rubber 
districts  the  subsoil  is  usually  safe  for  foundation  work,  but  in  the 
wet,  flat,  and  somewhat  swampy  plains,  in  parts  of  Malaya  and 
Sumatra,  the  difficulty  of  making  rehable  foundations  is  often 
accentuated. 

One  difficulty  frequently  experienced,  especially  when 
artificial  heating  apparatus  is  not  employed,  is  that  of  getting  a 
good  suppl}'  of  cool  air  through  the  building.  This  defect  is  often 
due  to  the  site  not  being  at  a  sufficient  altitude  and  to  the  building 
being  closely  surrounded  by  forest  trees  of  the  Hevea  type.     A  site 


PARA     RUBBER  377 

sufficiently  large  and  free  from  trees  is  therefore  desirable.  In. 
gently  undulating  country  a  slight  altitude  is  all  that  is  required 
to  ensure  a  good  circulation  of  air  through  the  building. 

Types  of  Factories  Required. 

The  type  of  factory  to  be  erected  depends  upon  many  factors, 
such  as  the  amount  of  the  crop  and  the  methods  of  curing  and 
washing. 

In  order  to  meet  crop  requirements  care  should  be  taken  to 
ensure  that  extensions  can  be  easily  and  economically  made  from 
time  to  time.  This  is  particularly  the  case  where  small  acreages 
come  into  bearing  regularly  each  year  for  many  years  in  succession. 
Where  the  whole  of  the  area  is  in  bearing,  the  building  need  not 
provide  for  extensions  to  the  same  degree,  though  an  annual 
increase  in  yield  per  acre  must  be  allowed  for. 

The  method  of  curing  also  has  a  bearing  on  the  type  of  factory 
required.  If  vacuum  driers  are  used  the  size  of  the  factory  can  be 
reduced.  If  artificial  heating  apparatus  is  provided,  the  rubber 
is  dried  more  quickly,  and  less  space  is  therefore  required  in  the 
curing  section.  The  installation  of  heating  apparatus,  fans,  etc., 
generally  necessitates  the  erection  of  a  two-storey  building. 
Smoking  must  also  be  considered,  though  in  many  cases  a  separate 
building  is  erected  for  this  phase  of  the  curing  process.  Frequently, 
however,  the  rubber  is  smoked  while  being  cured,  in  a  part  of  the 
factory  permanently  set  aside  for  this  work. 

The  kind  of  washing  machine  and  position  of  shafting  must  also 
be  considered  in  the  construction  of  the  walls  and  floor  of  a  factory. 
There  are  some  washing  machines  which  have  double  or  treble  the 
working  capacity  of  others,  and  which  dernand  comparatively 
less  space.  Shafting,  if  overhead,  may  require  wall  brackets, 
which  frequently  necessitate  an  entirely  different  construction. 
Floor  shafting,  on  the  other  hand,  may  be  erected  more  or  less 
irrespective  of  the  materials  used  in  the  construction  of  the 
building. 

Types   xow   Used   on    Plantations. 

Though  in  types  of  factories  now  used  on  plantations  there  is 
considerable  variation,  there  is  some  ground  for  hoping  that 
standardisation  will  ultimately  be  recognised.  If  rubber  planta- 
tion factories  were  standardised,  the  cost  would  be  appreciably 
lessened,  and  additions  more  easily  made.  A  width  of  forty  feet 
with  bays  ten  feet,  has  been  suggested  (Davidson,  Souvenir, 
I.R.J.)  as  the  standard  to  adopt. 

On  Eastern  estates  the  factories  are  either  :  (i)  entirely 
on  ground  floor,  (2)  two-storeyed  (or  more)  throughout,  or  (3) 
two-storeyed  only  in  the  curing  section.  They  are  provided  with  a 
space  for  the  engines  inside  the  factory,  or  a  separate  building 
adjoining  the  factory  is  reserved  as  the  power  station. 


378 


PARA     RUBBER 


One- Storey  Factories. 

The  first  type — one  storey  only — is  recommended  by  many 
firms  if  land  is  available.  Messrs.  Francis  Shaw  recently  (I.R.J., 
October  28th,  1911)  erected  one  of  this  pattern  on  Sennah  Estate, 
Sumatra.  The  main  building  was  120  feet  long  and  40  feet  wide, 
having  a  height  to  eaves  of  12  feet.  An  engine-house  and  engineer- 
ing shop  was  also  provided,  72  by  30  feet,  adjoining  the  main 
building.     Ventilation    was    partly    provided    for    by    means    of 


Fuaocf        fAcroiir 


ELEVATION   AND   GROUND   PLAN   OF   FACTORY     MESSRS.  SHAW 


expanded  metal  all  round  the  building  at  the  floor-level  and  similar 
metal  under  the  eaves  of  each  span.  In  factories  of  this  kind,  the 
washing,  curing  and  packing  sections  must  be  screened  off  so  as  to 
avoid,  as  far  as  possible,  the  introduction  of  mechanical  im- 
purities while  the  rubber  is  in  course  of  preparation. 

The  expense  of  erecting  lifts  for  conveying  the  rubber  to  and 
from  the  drying-room  and  of  building  staircases  is  avoided,  and 
carting  is  generally  simple  with  one-storeyed  factories. 

Two-Storey    Factories. 

The  second  type — two  storeys  throughout — has  often  been 
recommended  by  planters  with  long  experience  in  Ceylon  .where 
tea  and  cacao  curing-houses  of  this  kind  have  been  in  use  for  many 
years.  In  the  Souvenir  number  of  the  I.R.J,  there  is  an  illustra- 
tion shewing  the  construction  and  plan  of  a  building  recommended 


PARA     RUBBER 


379 


by  Mr.  L.  Davidson  (retired  planter),  after  consultation  with 
leading  planters  and  engineers  in  the  East.  In  this  class  of  building 
each  department  is  carefully  spaced ;  a  verandah  for  receiving 
scrap  and  latex,  despatching  and  box-marking  is  provided.     It 


PLAN    OF  FACTORY   RECOMMENDED   BY  WALKER    AND    SONS. 

will  also  be  noticed  that  on  the  ground  floor  is  a  vacuum-drying 
and  blocking  section,  if  such  is  required,  in  addition  to  a  second 
storey  reserved  entirely  for  curing.  The  building  stretches  about 
i6o  feet  in  length  and  50  feet  in  width,  apart  from  the  separate 
areas  occupied  by  the  engine-house  (30  by  40  feet)  and  boiler  and 


38o 


PARA     RUBBER 


fuel  verandah  (lo  by  30  feet).  A  complete  factory  such  as  this  is 
capable  of  turning  out  from  800,000  to  1,000,000  lb.  per  annum. 
The  factory  was  designed  so  that  it  could  be  built  in  sections, 
commencing  with  one  engine  and  three  washing  machines. 

Messrs  Walker  Sons  and  Co.,  have  supplied  me  with  blocks 
showing  the'  plan  of  the  ground  floor  of  a  two-storeyed  factory 
now  being  recommended  by  them.  The  capacity  of  the  factory 
is  estimated  at  1000  lb.  of  dry  rubber  per  day  of  ten  hours,  though 
some  extension  of  the  building  may  be  necessary,  when  the 
maximum  output  is  reached,  for  hanging  the  rubber  in  crepe  form 
for  a  few  days  before  packing.  The  plan  of  this  factory  is  shown 
on  page  379. 


SECTION    OF   FACTORY   RECOMMENDED   BY   WALKER  AND    SONS. 


The  capacity  of  the  "  Colombo  Rubber  Dryer"  shown  on  the 
above  plan  is  also  estimated  at  1000  lb.  in  an  ordinary  day,  with 
a  possibility  of  turning  out  nearly  double  that  quantity,  in  ten 
hours,  when  their  own  process  of  curing  is  adopted. 

Another  type  of  two  storey  factory  is  shown  in  the  plans 
supplied  by  Messrs.  W.  H.  Cochrane  and  Co.  In  this  the  upper 
storey  is  devoted  to  curing  by  artificial  means  and  to  packing. 
On  the  ground-floor,  offices,  lift  and  engines  are  spaced  out,  and  a 
lean-to  is  provided  at  each  end  of  the  building.  The  factory, 
illustrated  on  the  opposite  page,  is  70  by  35  feet,  the  height  from 
the  ground  to  the  first  floor  being  13J  feet,  and  from  the  first  floor 
to  the  eaves-level  10  feet.  The  height  of  the  roof  is  equal  to  one- 
fourth  of  the  span.  There  is  a  lean-to  on  one  side  on  the  ground- 
floor,  70  feet  long  and  12  feet  wide,  and  also  an  open  lean-to,  lO' 
feet  wide,  across  each  end. 

A  factory  has  been  erected  according  to  the  above  plans  in 
Sumatra  and  is  working  successfully. 

Two- storey  factories  are  cheaper  per  square  foot  of  floor 
space  than  buildings  all  on  the  ground  floor.  They  are  generally 
rectangular  in  shape,  though  some  have  been  erected  circular  in 


PARA     RUBBER 


3S1 


outline  with  the  object  of  mitigating  damage  during  squalls  or 
hurricanes,  frequent  in  Samoa  and  Sumatra.     " 

Two-Storey  Curing  Section. 

The  third  type — two  storeys  for  curing-section — is  occasionally 
adopted  on  Eastern  plantations.  Such  an  arrangement  allows 
the  manager  to  effectively  instal  and  work  artificial  heating 
apparatus,  owing  to  the  difference  in  elevation  of  the  curing- 
section.     The  second    storey    may    extend    along    one-third    to 


Cooling    Tanks. 

PLAN   OF    COCHRANE'S    FACTORY. 


half  the  length  of  the  ground-floor  building,  and  is  reserved  entirely 
for  drying  or  smoking  the  rubber,  steam  or  hot-air  pipes  being 
used  for  the  former.  The  upper  storey  is  generally  well  ventilated. 
A  lift,  in  addition  to  a  staircase,  usually  connects  the  two  floors. 

Materials  Used  in  Construction  of  Factories. 

Most  factories  are  steel-framed  and  covered  with  galvanized 
corrugated-iron  sheets.  Where  the  roof  is  not  provided  with  a 
timber  ceiling  the  air  is  apt  to  get  very  warm  in  the  tropics.  The 
sides,  or  walls,  are  usually  made  of  corrugated-iron  sheets  similar 
to  those  used  for  the  roof.  On  some  estates  timber  is  sometimes 
favoured,  in  which  case  it  is  advisable  to  use  wood  which  has  been 
impregnated  with  creosote  in  order  to  preserve  it  against  the 
attacks  of  white  ants.  Brick  walls,  between  the  iron  columns,  are 
not  often  erected  though  they  are  always  cool,  durable,  and  neat. 


382  PARA     RUBBER 

.Ventilation  of  Factories. 

Apart  from  health  reasons,  there  are  many  others  why  rubber 
factories  should  be  well  ventilated.  Rubber  contains  a  proportion 
of  putrescible  matter,  and  if  the  air  is  not  kept  pure,  bacteria  may 
appear  in  large  numbers  and  lead  to  deterioration  of  the  rubber 
during  curing.  Furthermore,  drying  is,  even  in  dry  weather, 
expedited  if  a  good  draught  of  fresh  air  is  maintained  through  the 
building.  The  majority  of  factories  rely  upon  open  windows  and 
doors,  together  with  a  fan,  for  their  supplies  of  fresh  air  ;  expanded 
metal,  which  is  so  constructed  as  to  allow  of  air  currents,  is  now 
used,  near  the  eaves  or  floor-level. 

Floors  of  Factories. 

The  ground-floor  is,  for  durability  and  cleanliness,  usually 
made  of  cement.  It  is,  however,  not  uncommon  to  find  white  ants 
boring  their  way  through  thin  layers  of  cement,  and  it  is  therefore 
necessary  to  see  that  all  floors  are  properly  made.  In  order 
that  water  may  be  carried  rapidly  away  from  the  washing  machines 
and  drip  racks,  channels  should  be  freely  provided.  The  floor 
requires  washing  at  regular  intervals  (preferably  with  water 
containing  some  cheap  disinfectant)  and  it  is  therefore  necessary 
to  construct  it  with  a  slope  of,  say,  one  in  eighty,  to  hasten  drying. 

Where  one-storey  buildings  are  installed  with  artificial 
heating  apparatus,  a  raised  timbered  floor  is  often  necessary. 
This  may  be  provided  with  spaces  for  the  passage  of  air,  and  be 
raised  above  the  level  of  the  ground  to  enable  steam  or  hot-air 
pipes  to  be  laid  and  to  create  a  hot-air  chamber  in  this  region. 

Light    and    Windows    in    Factories. 

The  bad  effect  of  light  on  rubber,  and  the  necessity  of  having 
abundance  of  light  in  the  machinery  sections,  require  the  adoption 
of  a  different  arrangement  in  various  parts  of  the  factory.  There 
can  hardly  be  too  many  windows  near  the  engines  and  washing  mills. 
These  should,  therefore,  be  provided  and  constructed  so  as  to 
open  inwards  for  draught  purposes. 

In  the  curing  room,  however,  windows  must  either  be  supplied 
with  red  glass,  or  curtains,  to  stop  the  chemical  rays  from  reaching 
the  rubber,  or  with  wooden  or  corrugated  iron  doors — which 
can  be  opened  from  the  inside  to  allow  Ught  to  enter  during  in- 
spection of  the  rubber.  It  is  necessary  that  the  rubber  in  the 
curing  room  be  frequently  inspected  in  order  that  the  development 
of  moulds  and  tackiness  may  be  arrested  in  the  initial  stages  ; 
hence  the  desirability  of  having  even  the  curing  room  well  supplied 
with  light  but  under  control. 

Doors  and  windows  should,  whenever  possible,  be  made 
to  close  on  the  inside  in  order  that  draughts  of  fresh  air  can  enter 
the  building  without  check. 

Timber  in  Factories. 

It  is  not  only  necessary  that  all  timber  used  in  the  factory 
should  be  well  seasoned  to  avoid  warping,  and  of  the  most  durable 


PARA     RUBBER  383 

kind,  but  it  is  also  advisable  to  protect  it  in  every  possible  way 
against  wet  and  dry  rot  and  various  pests.  In  most  tropical 
areas  white  ants  do  an  enormous  amount  of  damage,  and  in  order 
to  mitigate  this  evil  some  estates  have  insisted  on  all  the  timber 
being  creosoted,  not  only  externally,  but  also  internally.  The 
use  of  such  timber  in  the  curing-house  is  an  obvious  advantage. 
When  used  for  flooring  it  may  be  troublesome  to  the  bare  feet 
of  the  coolies.  Instead  of  creosote,  "  Jodelite  "  is  being  used  on 
some  plantations. 

The  drying  poles,  reapers,  or  shelves,  in  the  curing-room 
are  not  necessarily  very  expensive.  Jungle  and  bamboo  poles 
free  from  splinters  are  extremely  useful ;  otherwise,  planed 
reapers  similar  to  those  used  in  ceiling  work  are  generally  supplied. 

Heating  Apparatus. 

Various  forms  of  heating  apparatus  are  supplied  to  estates ; 
each  is  usually  associated  with  the  name  of  the  inventor  or  firm 
interested  in  it. 

It  is  apparent  that,  in  the  production  of  heat,  material  may 
be  used  which  will  emit  dense  volumes  of  smoke  capable  of  being 
used  in  the  smoking  as  well  as  drying  of  rubber. 

In  Cochrane's  system  the  heat  is  developed  in  iron  trucks  on  the 
ground-floor.  Three  or  more  of  these  trucks,  each  provided  with 
regulating  grate  bars  and  fitted  on  wheels,  are  used.  They  can 
be  easily  cleaned,  and  the  fire  started  outside  the  building.  The 
heat  is  driven  by  a  fan  through  ducts  to  the  drying-rooms.  It 
then  rises  through  expanded  metal  meshwork  laid  under  each 
rack  in  the  drying-room,  and  is  drawn  over  the  rubber  on  the 
racks  by  the  opening  of  adjustable  ventilators. 

The  "Chula"  Rubber  Drying  Plant. 

The  "Chula"  patent  air  heater  used  in  connection  with 
rubber  drying  and  curing  is  one  which  has  been  developed  largely 
in  connection  with  tea-drying.  It  consists  of  a  large  number  of 
tubes  placed  above  a  furnace  through  which  the  air  to  be  heated 
circulates. 

In  its  application  to  rubber  drying  several  methods  are 
possible.  One  is  to  divide  the  drying-loft  up  into,  say,  six  sections, 
and  by  means  of  a  large  fan  to  draw  hot  air  through  a  system 
of  light  steel  piping  fitted  with  numerous  outlets  controlled 
by  shutters.  The  first  day's  rubber  is  placed  in  the  first  section, 
and  the  following  day's  production  goes  into  the  next  chamber, 
and  so  on  until  the  seventh  day,  when  the  first  chamber  is  emptied 
and  re-filled.  Once  started  this  process  is,  therefore,  continuous, 
and  a  day's  manufacture  of  rubber  is  turned  out  every  day  dried, 
and,  if  necessary,  also  smoked.  Using  thin  crepe,  and  with  the 
fan  running  during  the  day  only,  two  days  have  been  found  suffi- 
cient to  thoroughly  dry  the  crepe,  although,  to  get  it  heavily 
smoked,  it  should  remain  from  four  to  six  days  in  the  chamber. 


384 


PARA     RUBBER 


Another  method  of  applying  the  ' '  Chula ' '  heater  to  a  curing- 
loft  is  to  have  one  large  chamber  with  the  fan  at  one  end  and  the 
heater  at  the  other.     At  both  ends  of  the  building  ducts  are  pro- 


rifflmfflfflrnfflim 


ELEVATION    (WITH    SECTION)    SHOWING   APPLICATION    OF 
"CHULA  "    HEATER. 

vided  to  cause  an  even  current  of  hot  air  or  smoke  through  the 
building. 

Temperatures  of  from  ioo°  to  iio°  F.  are  used,  and  the  air 
or  smoke  is  arranged  to  pass  through  the  drying-room  from  six  to 
eight  times  per  hour. 

The  same  apparatus  can,  as  in  the  previous  case,  be  used  for 
supplying  hot  smoke  and  air  to  the  drying-room.  Valves  are 
provided  above  the  tube  chamber  by  means  of  which  the  fumes 
from  the  furnace  can,  if  desired,  be  allowed  to  escape  and  mix  with 
the  hot  air.  When  smoke-dried  rubber  is  desired,  the  fire  is  fed 
with  suitable  green  fuel  on  a  low  fire.  (Albizzia  wood  and  leaves 
are  used  in  Ceylon  and  Lantana  in  S.  India.)     The  dense  smoke 


SECTION   THROUGH   DRYING   CHAMBER. 

rising  among  the  air-heating  tubes  is  cooled  down  by  the  air 
circulating  through  the  tubes,  and  when  allowed  to  escape  through 
the  valves  at  the  top  of  the  heater,  is  practically  at  the  same 
temperature  as  the  hot  air  from  the  tubes.     The  mixture  of  hot  air 


Lent   by    Indin-Iiuhher  Journal. 
DRYING    RUBBER   ON  THE    ESTATE, 


Lent  hy   India-Iiuhher  Journal. 
SORTING  AND  PACKING   RUBBER  ON  THE  ESTATE. 


SHAW'S  VACUUM    DRIER. 


PASSBURG'S  VACUUM  DRIER. 


PARA     RUBBER  385 

and  smoke  is  then  drawn  off  by  a  fan  and  delivered  to  the  curing- 
rooms  in  a  suitable  manner.  The  crepe  or  sheet  is  hung  in  the 
usual  way  and  the  drying  room  filled  with  smoke  at  a  slight  pressure 
which  is  distributed  evenly  throughout  the  chamber  by  means  of 
outlets  in  the  piping.  Each  section  of  the  drying- chamber  can  have 
its  smoke-supply  cut  off  by  means  of  a  valve.  For  producing  pale 
dry  rubber  the  smoke  valves  on  the  heater  are  closed  and  the 
chimney  valve  opened  and,  of  course,  a  dry  fuel  used  in  the  furnace. 
Pure  hot  air  only  is  then  obtained  for  passing  over  the  rubber. 

"Sirocco"    Drying    Plant. 

The  ' '  Sirocco ' '  drying  plant  can  also  be  used  on  rubber  planta- 
tions. .It  consists  of  a  "Sirocco"  air  heater  placed  in  an  air- 
tight chamber  in  the  centre  of  the  ground-floor  of  the  factory. 
The  stoking  is  effected  from  the  outside,  as  this  obviates  the 
necessity  of  bringing  fuel  into  the  factory  itself,  and  permits  the 
latter  to  be  kept  clean.  A  volume  of  air,  suitable  to  the  require- 
ments of  the  curing- rooms,  is  driven  by  means  of  a  centrifugal  fan 
into  the  air  chamber.  Having  been  heated  to  a  desired  degree,  it 
passes  into  a  horizontal  duct  extending  the  whole  length  of  the  first 
floor  of  the  building.  By  means  of  valves  the  warm  air  can  be 
admitted  from  the  duct  into  any  of  the  curing-rooms,  which  are 
kept  under  a  slight  pressure  due  to  the  fan  or  the  natural  draught. 
Temperatures  of  from  80°  F.  to  160°  F.  can  be  employed. 

Fans    in    Drying    Factories. 

Though  an  adequate  draught  of  fresh  air  is  frequently 
obtained  in  curing-rooms  without  the  use  of  fans,  these  appliances 
are  being  used  with  advantage  on  many  estates.  When  artificial 
heat  is  used,  fans  are  invariably  adopted  to  drive  hot  air  into  the 
building  or  to  draw  off  the  hot,  moisture-laden  air.  Even  where 
no  heating  apparatus  is  employed  the  use  of  a  fan  is  found  necessary 
when  large  crops  have  to  be  cured  in  the  shortest  time  possible.. 
When  fans  are  used  the  rubber  is  much  more  quickly  dried  and 
the  danger  of  moulds  and  other  objectionable  developments 
lessened.  The  capacity  of  different-sized  fans  is  given  in  various 
engineering  catalogues. 

Vacuum  Drying. 

The  fourth  method  is  that  of  drying  in  vacuum-chambers. 
In  the  previous  methods  large  spaces  involving  the  erection  of 
factories  are  necessary.  In  this  method  the  minimum  space  is 
required.  It  is  maintained  that  drying  in  vacuum  is  accomplished 
rapidly,  only  low  temperatures  are  necessary,  and  a  great  saving 
in  fuel,  space  and  labour  is  effected.  The  vacuum-drjang  chambers 
are  generally  rectangular  or  cylindrical  in  form  and  fitted  with 
plate  shelves  or  shelf  coils  inside.  A  vacuum  chamber  usually 
consists  of  a  large  iron  box,  of  from  100  to  200  cubic  feet  capacity 
or  even  larger,  fitted  inside  with  shallow  trays  having  perforated 
bottoms,  and  heated  with  steam  pipes  ;    the  interior  is  connected 


386  PARA    RUBBER 

by  an  iron  pipe  with  an  exhaust  pump.  For  heating,  live  or 
exhaust  steam  may  be  used,  or  even  hot  water.  The  temperature 
of  the  chamber  is  raised  to  90  or  100  F.,  and  after  the  air  has  been 
drawn  through  the  drier  for  a  few  hours  the  rubber  is  usually 
suiificiently  dry  for  most  purposes.  Most  manufacturers  and 
planters  have  not  adopted  drying  in  vacuum  as  they  believe  the 
rubber  is  softened  too  much,  and  the  nerve  more  or  less  perman- 
ently injured.  They  prefer  to  dry  the  rubber  gradually  in 
dark  warm  rooms. 

This  most  rapid  method  of  drying  can  be  applied  to  all  kinds 
of  rubber — biscuits,  sheets,  or  crepe — and  enables  one  to  manu- 
facture rubber  nearly  dry  in  a  sound  but  soft  state,  ready  for 
making  up  into  blocks.  The  rubber  is  allowed  to  remain  in  the 
vacuum  chamber  until  only  about  i  per  cent,  moisture  is  left  in 
the  rubber.  When  in  that  condition  it  should  be  removed,  as  if 
allowed  to  remain  until  the  whole  of  the  moisture  is  extracted 
the  rubber  seems  very  liable  to  resolve  itself  into  a  soft  treacly 
mass.  The  temperature  and  pressure  inside  the  chamber,  can, 
with  a  little  skiU,  be  easily  regulated,  and  providing  the  whole 
of  the  moisture  is  not  extracted,  good  results  may  be  anticipated. 
The  quantity  of  rubber  which  can  be  dried  in  a  given  time  by 
means  of  a  vacuum  chamber  depends  upon  the  capacity. 

There  are  many  kinds  of  vacuum  driers  now  on  the  market, 
notably  Passburg's,  Shaw's,  Bridge's  and  Robinson's. 

Method  of  Working  Passburg's  Drier. 

In  working  Passburg's  drier,  the  rubber  remains  in  the 
chamber  from  ij  to  2  hours.  About  10  lb.  of  wet  rubber  are 
spread  upon  each  tray,  the  chamber  supplied  to  plantations 
usually  receiving  190  lb.  per  charge.  The  steam  supply  is  shut 
off  about  a  quarter-of-an-hour  before  the  rubber  is  dry.  The 
heat  in  the  metal  of  the  chamber  completes  the  last  stage  of  the 
drying.  When  the  vacuum  is  about  28J  inches,  the  temperature 
of  the  rubber  remains  at  about  90°  F.  until  the  greater  part  of 
the  moisture  has  been  removed.  It  then  slightly  rises,  and  the 
rubber  is  taken  out  when  the  temperature  reaches  about  120°  F. 
The  pump  requires  about  i  H.P.,  but  the  exhaust  steam  from  the 
steam  cylinder  is  more  than  sufficient  for  heating  the  shelves  of 
the  chambers. 

In  the  Federated  Malay  States  a  very  low  steam  pressure 
in  the  shelves  is  used — from  i  to  4  lb.  only — and  on  some  estates 
the  rubber  may  be  left  in  for  i|  to  2  hours.  When  planters  desire 
more  output  from  a  chamber  they  will  probably  increase  the  steam 
pressure  and  shorten  the  drying  time.  At  the  end  of  the  drying 
process  the  rubber  is  hot  and  relatively  soft,  and  is  specially 
suitable  for  cutting  into  strips  and  conversion  into  block.  One 
can  make  satisfactory  dry  blocks  with  using  the  vacuum  chamber, 
as  it  not  only  gives  a  dry,  but  a  soft  product,  easily  manipulated. 
The  warm  rubber  on  cooling  sets  into  a  hard  block. 


PARA     RUBBER 


387 


Shaw's    Vacuum    Drier. 

Shaw's  make  special  sizes  of  vacuum  stoves  for  plantations. 
Each  stove  contains  20  shelves  ;  the  size  may  be  4  in.  by  4  in., 
6 in.  by  4 in.,  or  Sin.  by  4 in.,  these  respectively  taking  84, 126,  and 
168  lb.  of  rubber  per  charge.  Five  charges  per  day  can  be  dried, 
so  that  the  output  from  a  single  stove  may  be  considerable.  The 
installation  is  provided  with  a  pump,  condenser,  and  receiver 
capable  of  operating  two  stoves,  so  that  a  second  can  be  added 
when  found  necessary  without  incurring  double  expense. 

Messrs.  Jas.  Robinson  and  Co.,  Manchester,  also  make  vacuum 
driers  of  a  special  type. 

Bridge's   Vacuum   Drier. 

The  stoves  in  Bridge's  vacuum  driers  contain  14  shelves. 
Three  sizes  of  stove  are  made,  all  of  the  same  width  inside,  but  of 
different  depth  from  front  to  back,  the  depths  of  the  shelves  being 
I  foot,  3I  feet,  and  5^  feet  respectively.  From  experiments  made 
at  their  works  they  find  that  a  square  foot  of  moderately  thin  crepe 
weighiiig,  say,  J  lb.  to  the  square  foot,  can  be  dried  in  30  minutes, 
working  at  a  temperature  of,  say,  90°  F. 


bridge  s   vacuum  drier. 

Bridge's  mention  that  the  great  point  in  using  vacuum  driers 
is  to  see  that  the  rubber  is  evenly  creped,  so  that  one  part  does 
not  dry  more  quickly  than  the  other.  After  vacuum  drying  the 
rubber  is  not  fit  for  the  market,  but  it  can  be  readily  made  so  by 
passing  through  dry  rollers  once  or  twice  to  re-crepe  it,  or  several 
thicknesses  can  be  put  together  through  the  dry  rollers  and  made 
up  into  blanket,  or  the  rubber  may  be  blocked.  This  firm  think 
that  thick  blanket  and  block  are  the  best  when  vacuum  dr3dng  is 
adopted. 

General  Remarks  about  Vacuum  Drying. 

Vacuum  drying  is  generally  resorted  to  when  it  is  advisable  to 
rapidly  remove  the  moisture  without  subjecting  the  product  to  a 
very  high  temperature. 


388  PARA     RUBBER 

It  has  been  argued  that  with  drying  in  vacuum  chambers 
there  cannot,  owing  to  the  absence  of  air,  be  any  oxidation  ;  this  is 
to  some  extent  a  wrong  view  to  take  as  a  small  quantity  of  air  will 
probably  remain  in  the  vacuum  chamber  however  excellent  the 
exhaust. 

It  is  obvious  from  these  considerations  that  the  vacuum 
method  is  one  by  means  of  which  rubber  can  be  dried  in  the 
shortest  time,  and  material  turned  out  approximately  pure  and 
uniform.  On  some  estates  vacuum  driers  have  been  described  as 
' '  useless, ' '  and  on  others  as  ' '  indispensable. ' '  The  success  with 
which  such  a  complicated  piece  of  apparatus  is  used  depends,  very 
often,  on  the  engineering  skill  of  the  planter  in  charge.  Where 
skilled  supervision  has  been  provided,  vacuum  driers  have  been 
quite  a  success. 

In  amplification  of  some  remarks  on  a  previous  page,  attention 
may  be  drawn  to  some  recommendations  made  by  Mr.  J.  Darnley 
Taylor  in  reference  to  complaints  against  the  tendency  of  vacuum- 
dried  rubber  to  become  nerveless  and  tacky.  According  to  him 
(Tropical  Life,  April,  1910),  this  is  because  the  rubber  is  .allowed 
to  remain  in  the  chamber,  subjected  to  the  heat  of  the  shelves, 
with  the  inside  temperature  rising,  after  the  superfluous  moisture 
has  been  removed,  so  that  a  cooking  or  roasting  action  takes 
place.  He  submits  that  it  is  unnecessary  and  even  harmful  to 
make  the  rubber  "bone  dry."  The  last  2  or  2^  per  cent,  of 
moisture  is  the  most  difficult  to  remove,  and  requires  somewhat 
severe  measures.  Taylor  recommends  leaving  it  in,  when  the 
vacuum  chamber  is  used,  as  he  beHeves  that  it  prolongs  the  life  of 
the  rubber,  and  gives  greater  elasticity.  He  mentions  that  the 
first  indication  of  the  rubber  being  sufficiently  dried  is  when  the 
temperature  begins  to  rise,  further  corroboration  being  the 
cessation  of  the  dropping  of  condensed  vapour  into  the  receiver. 
Then  is  the  time  to  stop  drying. 

It  is  well  known  from  experience  on  many  plantations  in  the 
East,  that  by  means  of  vacuum  dryers  rubber  can  be  cured  at  the 
rate  of  200  to  330  lb.  per  two  hours  ;  this  represents  an  output  now 
anticipated  on  many  properties.  But  as  to  whether  the  rubber 
is  in  any  way  damaged  by  such  rapid  drying,  opinion  seems  to  be 
divided.  The  replies  received  from  manufacturers  who  have  been 
consulted  as  to  whether  they  would  recommend  planters  to  dry 
their  rubber  slowly  or  in  vacuum  chambers  are  all  against  rapid 
drying  ;  they  all  state  that  the  best  rubber  is  obtained  when  it  is 
slowly  dried. 

When  rubber  is  rapidly  dried  an  impervious  skin  may  form 
on  the  surface  owing  to  the  superficial  layers  being  dried  before 
the  internal  portion  ;  when  one  is  deahng  with  very  thin  sheets  or 
crepe  this  drawback  against  rapid  drying  is  not  very  formidable. 

At  the  conference  held  during  the  Rubber  Exhibition  of  last 
year,  Dr.  Esch  condemned  vacuum  drying  in  any  case,  in  spite  of 
the  good  results  sometimes  obtained. 


PARA     RUBBER  389 

Bubbles  and  Vacuum  Drying. 

Attention  has  been  called  to  the  number  of  air  and  steam 
hubbies  occurring  in  some  samples  of  sheet  rubber  dried  in  vacuum 
chambers.  Many  explain  this  by  stating  that  when  the  wet 
sheets  are  placed  in  hot  chambers  a  film  forms  on  the  surface, 
which,  to  some  extent,  prevents  the  escape  of  air  or  steam  ;  if 
the  temperature  is  then  lowered  very  suddenly  the  air  or  steam 
may  never  escape,  and  the  bubbles  therefore  remain  to  disfigure 
the  rubber.  Slowly-dried,  thin  sheets  do  not  usually  show  this 
disfigurement  to  the  same  extent,  and  one  may  conclude  that 
the  method  of  drying  is  at  fault.  These  bubbles  occur  just  as 
abundantly  in  an  average  lot  of  crepe  rubber  cured  in  vacuum 
chambers,  but  when  the  rubber  is  presented  in  this  form  the  bubbles 
do  not  show  up  very  conspicuously.  The  steam  bubbles  are 
formed  as  soon  as  a  partial  vacuum  is  secured,  the  water  boiling 
under  the  reduced  pressure  at  a  comparatively  low  temperature. 
This  feature  in  vacuum-dried  rubber  cannot  be  regarded  as  a  very 
serious  obstacle,  especially  if  the  planters  must  convert  the  hot, 
dry  rubber  into  loaves  or  blocks  in  the  minimum  time. 

MiCHIE-GOLLEDGE     PROCESS     OF     RAPID     DRYING. 

I  am  indebted  to  Mr.  Michie,  of  Walker,  Sons  &  Co.,  London, 
for  the  following  description  of  the  Michie- Golledge  curing  process, 
which  enables  planters  to  turn  out  dry  rubber  in  the  minimum 
time  without  the  use  of  vacuum-driers.  Rubber  cured  by  this 
process  is  ready  for  despatch  in  one  or  two  days  after  the  latex 
is  taken  from  the  trees. 

Latex  is  coagulated  in  three  to  four  minutes  by  means  of  the 
Michie- Golledge  hand-driven  coagulating  machine,  these  machines 
being  placed  in  sheds  at  places  where  latex  from  the  various  fields 
can  be  conveniently  collected.  Immediately  after  coagulation 
the  rubber,  while  still  in  a  plastic  state,  is  passed  through  a  small 
hand-roller  and  rolled  into  sheets.  These  sheets  are  taken  to  the 
factory  or  curing-store,  and  are  at  once  cut  into  strips  by  a  special 
machine.  The  strips,  spread  on  wire  trays,  are  placed  inside 
drying-chambers,  through  which  slightly  heated  air  is  drawn  or 
forced  by  a  fan.  When  smoke-cure  is  required,  smoke  is  passed 
with  the  air  through  the  strip  rubber  during  the  drying  process. 
One  or  two  hours  suffice  to  thoroughly  dry-cure  the  "strip," 
which  is  then,  if  the  rubber  is  to  be  finished  in  crepe  or  sheet 
form,  passed  through  the  crepe  or  sheet  mills. 

I  have  seen  this  process  in  working  order,  and  consider  it 
one  of  few  complete  systems  capable  of  rapidly  dr3ang  rubber 
without  the  use  of  vacuum  driers.     It  is  a  simple  and  yet  very 
effective  process.      The  process  is  followed  upon  such  estates  a 
St.  George's,  Panawattee,  UdapoUa,  Neuchatel,  and  Periyar. 

Drying  of  Air  in  Refrigerating  Chamber. 

In  a  recent  patent  by  Marlow,  the  rubber  is  hung  in  a  dark 
chamber,  which  is  exhausted  to  a  vacuum  of  two  inches  of  water ; 


390  PARA     RUBBER 

an  air-blower  is  then  inserted,  and  through  it  the  previously 
dried  air  is  passed,  this  air  having  been  dried  in  a  refrigerating 
chamber,  after  which  its  temperature  is  raised  again. 

It  has  been  pointed  out,  by  some  authorities,  that  no  sugges- 
tion has  yet  been  made  for  drying  the  air  by  coohng  it  to  the 
condensation  point  of  the  bulk  of  the  contained  moisture. 


CHAPTER  XXV. 

THE  SMOKING  OF  RUBBER 

A  great  part  of  the  rubber  from  plantations  is  shipped  without 
being  in  any  way  smoked.  In  fact,  some  forms  of  plantation 
rubber,  especially  well-washed  crepes,  are  never  subjected  to  this 
treatment.  Nevertheless,  this  process  has  been  adopted  with 
advantage  by  many  planters,  and  is  worthy  of  consideration 
at  the  present  juncture. 

When  dealing  with  yields  and  preparation  of  rubber  from  the 
Amazon,  mention  has  been  made  of  the  smoking  method  adopted 
in  that  region.  Furthermore,  we  have  just  seen  how  in  many 
factories  recently  erected  in  the  East,  a  separate  part  of  the  building 
has  been  set  apart  for  smoking  only. 

Advantages  of  Smoking. 

The  benefits  to  be  derived  by  smoking  rubber  depend  upon 
the  thoroughness  with  which  the  raw  material  is  impregnated 
with  the  antiseptic  and  preserving  substances  contained  in  smoke, 
upon  the  condition  of  the  rubber  being  so  treated,  and  whether 
the  rubber  is  smoked  internally  or  externally. 

The  most  apparent  effect  of  smoking  is  reduction  in  the 
number  of  cases  showing  tackiness  and  moulds.  Properly 
smoked  sheet  rubber,  if  packed  dry,  can  be  stored  for  many  months 
without  becoming  soft  or  mouldy.  Crepe,  not  smoked,  keeps 
equally  well,  probably  because  the  substances  on  which  the  develop- 
ment of  moulds  and  tackiness  largely  depend  have  been  almost 
entirely  removed  during  the  washing  process  through  which 
all  such  rubber  passes. 

Smoking  and  Strength  of  Rubber. 

Apart  from  the  good  effects  on  the  keeping  properties,  smoking 
appears  to  improve  the  streingth  of  the  rubber,  especially  when 
effected  internally.  The  better  physical  properties  of  fine  hard 
Para  compared  with  the  average  plantation  product  have  for 
many  years  been  associated  with  the  smoking  process  in  the 
Amazon.  This  might  well  be  the  case  seeing  that  readily  decom- 
posible  substances  are,  during  coagulation,  covered  with  pre- 
servatives contained  in  the  smoke,  the  liability  to  internal  decom- 
position and  degeneration  being  thereby  minimised.  If  this  is 
the  correct  view,  it  would  certainly  appear  worth  while  smoking 
even  crepe,  washed  scrap,  and  any  other  forms  of  washed  rubber, 
especially  as  this  can  be  done  at  very  little  extra  cost. 


392 


PARA    RUBBER 


Demand  for  Smoked  Rubber. 


That  there  is  a  decided  preference  for  smoked  rubber  from 
plantations  .is  evident  from  the  fact  that  this  type  has  been 
acquired  by  the  payment  of  substantial  premiums  over  the  un- 
smoked  plantation  product.  This  premium  has  been  maintained  for 
several  months  in  succession,  and  though  it  will  in  all  probability 
diminish  or  disappear  when  smoked  rubber  is  available  in  large 
quantity,  its  existence  i  good  testimony  to  the  opinion  in  which 
it  is  held  by  buyers. 

A  most  striking  acknowledgment  to  smoked  rubber  was 
paid  at  the  Rubber  Exhibition,  191 1,  when  the  "India- Rubber 
Journal  Shield"  and  "Grenier's  Trophy"  were  offered  for  the 
best  plantation  rubber  in  the  world.  Both  prizes  were  won  by  one 
exhibitor  of  smoked  rubber,  and  those  exhibits  nearest  the  winning 
lot  were  smoked.  The  value  of  this  verdict  was  very  great.  It 
appears  that  separate  groups  of  technologists,  manufacturers, 
and  rubber  brokers  were  selected  to  examine  the  exhibits  for  each 
of  the  two  awards.  Though  the  methods  of  the  two  groups  of 
judges  were  quite  unknown  to  each  other,  the  smoked  rubber 
from  the  same  estate  gained  the  highest  number  of  marks  in  each 
competition.  This  decision,  strengthened  by  the  fact  that  nearly 
all  the  runners-up  in  each  competition  exhibited  smoked  rubber, 
was  regarded  as  a  definite  pronouncement  in  favour  of  smoked 
as  against  the  unsmoked  plantation  product. 

Of  course  this,  as  well  as  other  kinds  of  plantation  rubber, 
is  subject  to  the  laws  of  supply  and  demand.  In  fact,  at  the 
moment  of  writing,  merchants  are  asking  planters  to  make  crepe 
in  preference  to  smoked  or  unsmoked  sheet  ;  but  this  is  on  account 
of  the  market  condition  in  relation  to  forward  contracts  for  these 
classes  of  rubber. 

Methods  of  Smoking. 

There  are  various  methods  of  smoking  adopted  in  wild 
and  plantation  districts.  In  the  Amazon  region,  and  also  as  the 
basic  principle  in  many  of  the  recent  inventions  designed  for  use 
on  plantations,  the  rubber  is  smoked  internally  as  the  latex  is 
being  coagulated,  this  being  considered  to  have  a  better  effect  on 
the  physical  properties  of  the  finished  product. 

On  most  plantations  smoking  is  external  only  and  is  com- 
parable, to  som;  extent,  with  the  surface-smoking  of  common  food 
stuffs  in  this  country  both  in  respect  of  method  of  procedure  and 
effects.  The  rubber  when  smoked  externally  is  suspended  on 
racks  or  poles,  in  a  chamber  filled  with  smoke  from  a  smouldering 
fire,  until  it  has  been  thoroughly  covered  with  the  smoke,  the 
final  stage  being  determined  by  colour  and  smell. 

The  rubber  may  be  placed  in  the  smoking-chamber  in  the  wet 
or  in  an  almost  dry  state  ;  it  is  usually  transferred  to  the  smoking- 
shed  after  being  allowed  to  drip  for  a  day  or  two,  and  is  kept  there 
until  thoroughly  dry. 


PARA     RUBBER  393 

Smoking   Coincident   with   Other   Processes. 

It  will,  therefore,  be  quite  clear  that  whether  internal  or 
external  smoking  methods  are  adopted,  certain  other  changes  are  in 
progress  during  this  stage.  In  the  internal  methods,  coagulation  is 
proceeding  hand-in-hand  with  the  smoking  of  every  particle. 
When  surface-smoking  is  adopted,  drying  is  generally  accom- 
plished in  the  same  period.  In  the  former  method,  the  rubber 
is  usually,  but  not  always,  shipped  in  the  wet  and  unwashed 
state  ;  in  the  latter,  the  rubber  is  washed  before  being  smoked, 
and  is  generally  shipped  in  the  dry  condition.  It  is  this  connection 
between  the  smoking  methods  and  the  coagulating,  drying  and 
washing  processes  that  leads  to  such  entirely  different  factory 
arrangements  in  rubber-producing  areas. 

The  Amazon  Method. 

The  method  adopted  in  the  preparation  and  smoking  of 
fine  hard  Para  can  be  taken  as  the  standard.  Most  of  the  new 
inventions  are  based  on  the  principles  of  the  method  employed 
by  the  natives  in  the  Amazon  region. 

In  Brazil  the  latex  is  poured  into  a  shallow  basin  60  cm.  to  i 
metre  in  diameter  and  20  to  30  cm.  deep,  and  pieces  of  bark,  dirt, 
&c.,  removed.  A  fire  is  then  made  of  wood  and  resinous  substances, 
and  is  kept  going  either  with  green  branches  of  Mimusops  elata, 
or  with  palm  nuts  from  Attalea  excelsa  and  Maximiliana  regia. 
These  palms  are  usually  grown  in  botanic  gardens  in  various  parts 
of  the  tropics,  the  latter  species  being  more  commonly  known 
as  the  "Cocurito"  palm.  A  chatty,  open  at  both  ends,  or  a  cone, 
is  placed  on  the  fire  and  the  smoke  allowed  to  issue  from  the  upper 
aperture. 

A  paddle-like  implement  is  then  dipped  into  or  covered  with 
the  latex,  and  held  over  the  smoke  until  the  latter  is  coagulated. 
It  is  stated  by  Bonnechaux  that  8  litres  of  latex  are  completely 
coagulated  in  about  ij  hours  by  these  means.  The  same  principle 
is  said  to  be  adopted  in  parts  of  the  Congo  in  the  preparation  of 
Landolphia  rubber. 

The  Constituents  of  Smoke  from  Attalea  Nuts. 

These  have  been  partly  determined  by  Frank  and  Gnadiger. 
On  combustion  of  the  nuts,  there  are  obtained  io-o8  per  cent,  of 
tar,  46-4  per  cent,  of  watery  distillate,  29-10  per  cent,  of  charcoal, 
and  14-51  per  cent,  of  gases.  Neither  the  tar  nor  the  watery 
distillate  differ  greatly  in  composition  from  the  similar  products 
obtained  from  beechwood.  In  the  tar  were  identified  methylpy- 
rogallol,  dimethyl  ether,  coerulignol,  cresol,  guaiacol,  homo- 
pyrocatechol,  a  sesquiterpene,  and  pyridine  derivatives.  In 
the  aqueous  distillate  were  large  quantities  of  formaldehyde  and 
acetone,  and  in  addition  xanthogallol,  homopyrocatechol  and 
formic,  acetic  and  propionic  acids. 


394  PARA     RUBBER 

Other  Internal  Smoking  Processes. 

Ridley  (Straits  Bulletin,  1910),  devised  a  novel  method  of 
smoking.  Spindles,  flat  and  towards  the  centre  broad,  were  used  ; 
these,  when  made  to  revolve,  dipped  into  the  latex  and  passed 
through  a  smoke  chamber.  Samples  of  the  rubber  were  sub- 
mitted to  a  manufacturer  for  testing.  The  loss  in  washing  was 
13  per  cent,  compared  with  18  per  cent,  for  fine  hard  Para.  The 
rubber  was  extremely  like  the  latter  in  tensile  strength  and  power 
of  recovery,  but  was  slightly  softer  and  required  a  different 
vulcanizing  heat.  Tests  of  the  elasticity  and  tensile  strength  made 
at  different  times  during  the  experiments  show  that  at  the  proper 
vulcanizing  heat  it  was  as  durable  as  fine  hard  Para. 

Sutton's   Apparatus. 

This  also  is  based  upon  the  Brazilian  method  of  smoking  upon 
paddles.  There  is  a  series  of  paddles  revolving  in  a  circuit,  and 
each  is  made  to  dip  in  turn  into  a  vessel  containing  the  latex, 
making  two  or  three  turns  in  it.  After  a  paddle  has  thus  received  its 
coating  of  latex,  it  passes  through  a  chamber  filled  with  smoke 
generated  by  a  specially  constructed  creosote  apparatus.  The 
paddles  are  kept  revolving  until  each  has  a  sufficiently  thick 
coating  which  is  cut  off  and  forms  a  sheet.  It  is  claimed  that  one 
man  can  attend  to  several  machines,  and  that  the  temperature  is 
under  complete  control.  A  smaU-sized  machine  with  six  paddles 
is  being  tested  in  the  East,  but  machines  with  many  more  paddles 
can  be  made. 

The  Derry  and  Bertram  Methods. 

In  both  of  these  an  endless  band  is  made  to  dip  into  the  latex 
and  to  run  during  part  of  its  course  through  a  smoke  chamber. 
The  coagulated  rubber  is  cut  off  in  the  form  of  long  sheets.  Derry's 
apparatus  has  been  tried  in  Malaya  ;  the  method  is  highly  spoken 
of,  and  the  rubber  obtained  is  said  to  be  excellent.  Bertram's 
apparatus  has  various  modifications,  one  of  which  is  the  introduc- 
tion of  a  roller  which  revolves  continuously  in  the  latex  and  is  in 
contact  with  the  band,  which  does  not  itself  dip  into  the  latex,  but 
receives  it  from  the  roller.     This  apparatus  is  driven  by  hand. 

Wickham's  Smoking  Process. 
In  this  apparatus  dense  smoke  is  produced  in  a  furnace,  this 
being  effected  by  burning  oily  nuts  of  palms  with  charcoal.  The 
latex  is  poured  into  the  lower  portion  of  a  cyhnder  and  the  latter 
is  then  rotated.  The  smoke  is  passed  through  a  hollow  axle  of 
the  cylinder.  When  the  cylinder  rotates,  the  bulk  of  the  latex 
will  remain  in  the  lower  segment,  but  a  thin  film  will  adhere  to  the 
inner  surface  of  the  cylinder  and  be  carried  round  with  it  and 
exposed  to  the  smoke  which  cures  and  coagulates  the  rubber, 
forming  a  skin  of  solidified  rubber  on  the  inner  surface  of  the 
cylinder.     During  the  next  rotation  a  fresh  film  of  latex  is  carried 


PARA     RUBBER 


395 


round  on  the  surface  of  the  first  skin  and  in  its  turn  cured  and 
coagulated,  and  this  may  be  continued  till  a  ring  of  rubber  of  con- 
siderable thickness  is  formed  which  can  be  pulled  out  of  the  cylinder. 
The  setting  of  the  rubber  films  can  be  observed  through  the 
opening  in  the  side  of  the  cylinder,  and  the  speed  of  rotation 
regulated  accordingly.  By  this  means  the  whole  of  the  latex 
treated  is  exposed  in  successive  thin  films  to  the  action  of  the 
smoke,  and  a  well-cured  and  homogeneous  rubber  is  obtained. 

This  method  was  devised  to  closely  imitate  the  Amazon 
method,  but  there  are  no  reports  available  regarding  its  wide 
adoption  on  Eastern  plantations. 

Da    Costa    Smoking    and    Coagulating    Plant. 

This  process  for  coagulating  latex  and  at  the  same  time  in- 
corporating creosote  with  the  rubber  was  put  on  the  market  by 
Messrs.  Bridge  and  Co.,  and  depends  upon  the  injection  of  smoke 
directly  into  the  latex  by  means  of  steam,  compressed  air,  or  with 
a  jet  of  water.     The  plant  consists  of  boiler,   smoke-producer, 


smoke-sifter  (or  soot-filter),  and  coagulating  trolley  bearing  the 
coagulating-chamber,  together  with  the  necessary  piping,  fittings, 
etc.  The  smoke  is  made  from  any  kind  of  wood,  leaves,  twigs, 
etc.,  and  is  thoroughly  sifted  by  baffle-plates  to  extract  all  particles 
of  soot  previous  to  its  being  injected  into  the  latex.  To  ensure  its 
even  distribution,  the  smoke  is  diverted  from  the  soot-filter  to 
two  pipes.  The  latex  chamber  is  mounted  on  a  trolley  and  is 
fitted  with  a  tipping  arrangement  actuated  by  worm  gear  and  hand 
wheel.  An  instantaneous  connection  can  be  made  between 
the  pipes  fixed  to  the  coagulating  chamber  and  the  pipes  leading 
from  the  smoke  producer.  While  the  coagulating  process  is  going 
on,  another  coagulating  chamber  on  its  trolley  is  being  discharged 
of  coagulated  rubber  and  re-charged  with  latex.     The  force  of  the 


396 


PARA    RUBBER 


injection  violently  agitates  the  latex,  and  during  this  operation 
■every  particle  is  reached  by  the  smoke.  In  a  short  time  the  whole 
mass  coagulates  and  the  floating  rubber  can  be  removed.  It  may 
be  prepared  as  crepe,  or  be  blocked. 

Dickson's   Smoker   Coagulator. 
The  smoke  is  generated  in  a  small  furnace  below  the  coagulat- 
ing chamber,  and  before  passing  into  the  latter  filters  between 
baffle-plates.     In   the   coagulating  chamber   is    a  large    drum    in 


-contact  with  a  roller  which  is  partly  immersed  in  a  shallow  pan 
containing  latex.  The  roller  is  turned  by  hand  or  power,  when  it 
causes  the  drum  to  revolve,  depositing  on  it  at  the  same  time  a 
continuous  film  of  latex  which  is  coagulated  by  combined  heat  and 
smoke.  When  there  is  a  thick  deposit  of  rubber,  the  smoke  is 
shut  off  by  a  damper,  and  a  door  in  the  coagulating  chamber  is 
opened  through  which,  after  slitting  across  with  a  knife,  the  rubber 
is  withdrawn  in  the  form  of  a  large  sheet. 


PARA     RUBBER  397 

Shaw's   Smoking   System. 

In  this  apparatus  (I.R.J.,  April,  1911),  coagulation  is  effected 
by  forcing  smoke  through  the  latex  by  means  of  compressed  air 
led  from  a  belt-driven  air  compressor.  The  advantages  claimed 
are  :  (i)  latex  is  coagulated  at  a  definite  temperature  that  can  be 
ascertained  and  adhered  to  ;  (2)  live  steam  at  a  high  temperature 
is  not  brought  into  direct  contact  with  the  latex  ;  (3)  the  smoke 
is  cooled  by  the  compressed  air  before  reaching  the  latex.  This 
apparatus  may  commend  itself  to  those  who  are  nervous  about  the 
use  of  live  steam.  The  tanks  are  now  made  of  porcelain  with 
aluminium  covers  to  ensure  cleanliness  and  are  made  in  standard 
sizes  to  hold  25  and  50  gallons  of  latex  each.  They  are  water- 
jacketed,  the  water  being  heated  to  a  constant  level  to  ensure 
coagulation  being  always  effected  under  similar  conditions. 

The  "Fumero"  Apparatus. 

Van  den  •  Kerckhove  has  patented  an  apparatus,  called  the 
"Fumero,"  designed  for  use  on  plantations  where  the  smoking 
of  rubber  is  desired.  The  "Fumero"  is  about  80  cm.  (32  in.)  in 
height,  can  be  transported  by  hand  from  one  place  to  another,  and 
when  lighted  emits  smoke  containing  creosote.  The  inventor  states 
that  coagulation  is  effected  without  the  addition  of  acid,  and  the 
rubber  can  be  made  up,  finally,  in  the  form  of  sheets,  biscuits, 
balls,  etc.  It  was  explained  by  the  writer  at  the  Ceylon  Rubber 
Exhibition  that  hot  smoke,  from  smouldering  logs  of  wood  which 
had  been  previously  steeped  in  creosote,  brought  about  coagulation 
of  the  latex  through  which  it  was  passed. 

Krebs's  Patent  Smoking  Apparatus. 
Here,  instead  of  allowing  the  fumes  to  come  directly  into  con- 
tact with  the  latex,  they  are  passed  through  water,  which  traps- 
some  of  the  constituents,  this  water  being  added  to  the  latex 
to  produce  coagulation.  To  generate  the  fumes,  wood  is  slowly 
burned  in  a  forced- draught  furnace  and  they  are  driven  through 
the  water  by  means  of  a  hand  or  mechanically-propelled  fan.. 
The  residual  fumes  may  be  passed  on  to  the  drying-room. 

Surface-smoking  on  Estates. 
The  foregoing  methods  are  all  based  on  the  Amazon  system 
of  impregnating  every  particle  of  rubber  with  the  constituents  of 
smoke.  In  the  surface-smoking  methods  which  predominate  on 
Eastern  plantations,  smoking  is  almost  entirely  superficial. 
Various  systems  are  adopted,  the  smoking  chamber  sometimes 
being  of  a  temporary  character  and  at  other  times  a  fixed  part  of 
the  factory.  In  the  latter  case  the  smoking  section  may  be 
in  a  compartment  attached  to,  or  be  an  integral  part  of,  the  main 
building. 

Sources  of  Smoke. 

The  smok'J  is  obtained  from  various  sources.     On  Klanang 
estate,  where  smoked  sheet  of  first-class  quaUty  is  turned  out. 


.398  PARA    RUBBER 

coconut  husks,  with  a  small:  quantity  of  hard  wood,  are  used 
to  generate  the  smoke.  The  freshly-washed  sheets,  after  being 
allowed  to  drip,  are  exposed  to  the  smoke  and  are  said  to  be  dry 
and  ready  for  packing  in  about  one  week. 

On  other  estates  old  railway-sleepers,  or  timber  soaked  in 
creosote,  are  allowed  to  smoulder.  A  dense  smoke  is  obtained 
from  such  material,  though  the  addition  of  creosote  is  said  to 
sometimes  raise  the  temperature  and  lead  to  too  rapid  combustion. 
On  other  properties  certain  common  native  woods,  known  for  the 
dense  smoke  they  emit  while  smouldering,  are  used.  Waste 
■coconut-dust  and  sawdust  have  sometimes  been  used,  but  have 
been  abandoned  on  account  of  their  frequently  giving  off  sparks 
of  wood  which  settle  on  the  surface  of  the  rubber  and  also  increase 
the  fire  risks. 

Fires  and  Supervision  During  Smoking. 

It  appears  to  be  the  general  practice,  where  the  smoking 
chamber  is  not  a  part  of  the  main  building,  to  have  the  fire-places 
sunk  in  the  floor  or  placed  on  the  bare  earth.  Under  these 
circumstances  the  kiln  principle  appears  to  be  the  safest.  By 
means  of  baffle-plates  the  smoke  can  be  delivered  to  any  part  of 
the  chamber  where  the  rubber  is  hanging. 

There  is  very  little  supervision  required,  and  the  danger 
from  fire  is  generally  small. 

The  safest  principle  of  all,  and  one  allowing  almost  perfect 
control,  is  to  have  a  smoke-generating  apparatus  outside  the 
building,  such  as  the  "Chula"  type. 

Under  ordinary  circumstances,  the  timber  or  coconut  shells 
are  allowed  to  smoulder  all  day,  the  fires  being  renewed  at  frequent 
intervals.  The  smoke  should  be  dry  for  the  benefit  of  the  rubber 
and  the  coohes  working  in  it.  There  are  certain  risks  from  fire, 
but  these  can  be  minimised  if  the  fire  is  sunk  in  the  ground  and 
smouldering  only — which  does  not  increase  the  temperature 
greatly — is  permitted. 

The  rubber  should  be  turned  over  occasionally,  so  that  it 
may  be  smoked  as  evenly  as  possible.  If  this  is  not  done,  the 
part  of  the  rubber  touching  the  pole  or  support  will  remain  pale 
in  colour  and  thus  spoil  the  appearance  of  the  sheet. 

Creosote-Generating   Apparatus. 

A  creosote-generating  apparatus  has  been  recently  brought 
forward  by  Sutton,  based  on  the  vaporisation  of  creosote  by 
allowing  it  to  drip  upon  a  heated  surface.  The  creosote  drops 
through  small  nozzles  fitted  with  needle- valves  upon  a  pan  heated 
by  a  paraffin  oil-lamp.  Should  the  creosote  upon  the  pan  take 
fire,  the  supply  is  shut  off  automatically.  Should  the  lamp  go 
out,  the  overflow  of  unheated  creosote  is  provided  for.  The 
apparatus  is  placed  in  the  drying  or  smoking-room.  It  can  be 
easily  managed  by  a  native. 


PARA     RUBBER 


399 


Buildings  for  Surface-Smoking. 

On  many  estates  the  smoking-house  is  constructed  of  mud  and 
timber  or  of  timber  only.  The  plan  is  often  extremely  simple 
and  the  cost  of  erection  small. 

Upon  an  estate,  the  smoked  sheets  from  which  realize  very 
nearly  the  top  prices  at  the  auction  sales,  three  houses  differing 
somewhat  in  construction  are  used.  The  first  is  a  square  house 
12  ft.  by  12  ft.,  with  bars  running  across  the  open  top,  which  is 
14  feet  from  the  ground.  Above  the  fire,  three  feet  from  the  ground- 
level,  is  hung  an  iron  sheet,  and  above  it  again  is  stretched  wire 
netting  to  prevent  any  rubber  falling  into  the  fire. 

The  second  house  is  built  12  ft.  by  12  ft.  and  16  ft.  high,  with  a 
pit  5  ft.  deep.  This  house  has  a  covered-in  top,  a  small  hole  being 
left  in  the  centre  to  allow  the  smoke  to  escape.  Three  feet  from 
.  the  ground-level  sheets  of  iron  are  hung  over  the  fires,  and  i  foot 
above  this  is  the  bottom  of  the  first  drawer.  There  are  many 
drawers,  each  6  ft.  by  6  ft.  by  6  in.,  laid  on  top  of  one  another  as 
far  as  the  roof.  They  draw  to  the  outside,  a  platform  being 
erected  to  allow  of  their  being  filled.  There  are  four  tiers  of  these 
drawers,  56  in  all,  and  they  are  formed  of  a  framework  of  wood 
with  wire-netting  stretched  across  the  bottom.  Smaller  sheets 
are  smoked  in  this  house. 

The  third  house  is  a  corrugated  iron  building,  40  ft.  by  25  ft., 
.and  25  ft.  high.  In  a  chamber  on  the  ground-level,  10  ft.  wide 
at  the  bottom  and  22  ft.  at  the  top,  the  fires  are  placed.  At 
10  ft.  from  the  ground  is  a  wooden  ceiling  (the  floor  of  the  chamber 
above)  in  the  centre  of  which  is  a  space  6  ft.  wide  and  30  ft.  long, 
covered  with  wire-netting,  for  the  upward  passage  of  the  smoke. 
Rattans,  the  width  of  the  building,  are  stretched  across  the  upper 
chamber  10  ft.  above  its  floor  to  support  the  rubber  when  drying. 
The  fires  below  are  protected  with  sheet  iron  as  in  the  other 
forms  of  houses.  Ordinary  green  wood  from  the  new  clearings  is 
used,  and  sawdust  is  kept  caked  upon  the  top  to  prevent  the 
formation  of  flames. 

Smoking-House  at  Singapore. 

Ridley  {I.R.J.,  April,  1911),  has  given  the  following  des- 
cription of  a  building  which  he  found  useful  at  the  Botanic  Gardens, 
Singapore  : — 

"The  building  is  55 J  ft.  long  and  19  ft.  wide,  oblong  in 
shape,  and  made  of  ordinary  planking  with  a  high  roof.  The  plank 
walls  are  8  ft.  high,  and  the  roof  of  attaps,  15  ft.  high  in  the 
centre.  The  floor  is  cemented,  with  concrete  below.  There  are 
two  or  three  windows,  which  can  be  opened  when  required,  and 
one  entrance  door.  The  building  is  erected  on  a  slope  of  about  i  in 
12,  and  drains  run  down  the  side  to  carry  off  rain  water  ;  inside 
are  wooden  posts  sunk  in  the  ground  between  which  run  thin 
rattans  stretched  tight  over  which  the  rubber  is  hung.  Near  the 
door  are  sunk  in  the  concrete  and  cement  floors  circular  pits 
I  ft.  wide  and  3  ft.    deep  in  which  the  fire  is  put,  and  then  are 


400  PARA     RUBBER 

covered  with  iron  cones  with  a  flat  perforated  top.  These  cones 
are  22  in.  high.  They  have  a  small  oblong  opening  at  the  base 
to  admit  air  to  the  fire.  Three  of  these  fireplaces  keep  the  room 
full  all  day,  but  there  are  others  at  the  upper  end  of  the  building 
which  can  be  used  to  increase  the  smoke,  if  required,  either  for 
exceptionally  heavy  smoking  or  when  the  building  is  quite  full 
of  rubber.  The  newest  made  rubber  is  put  nearest  the  fires  so 
as  to  get  the  most  smoking  and  moved  further  up  the  slope  as  it 
gets  drier. 

"All  smoke  contains  a  certain  proportion  of  water,  and  this, 
with  the  free  creosote  and  naphtha,  are  practically  absorbed  by 
the  woodwork  and  attaps,  so  that  the  rubber  is  not  covered  with  a 
wet  unpleasant  layer.  At  one  time  a  brick  smoking-room  with  a 
corrugated  iron  roof  was  built.  In  this  house  the  fire  was  outside 
and  the  smoke  was  conducted  in  by  a  tube,  but  it  was  soon  found 
that  there  was  deposited  on  the  floor  and  elsewhere  in  the  rooms 
a  thick  brown  liquid  consisting  of  naphtha  and  water.  This 
stuff  got,  too,  on  the  rubber,  but  is  quite  absent  from  the  wooden 
drying  house.  Though  the  woodwork  gets  dark  brown  or  black 
from  the  deposited  products  of  the  smoke,  the  rubber  is  dry  and 
of  good  colour. ' ' 

Smoking  in  the  Main  Building. 

On  many  estates  the  smoking  compartment  is  a  part  of  the 
factory.  Where  the  building  is  all  on  the  ground  floor,  the  smoking 
section  is  at  one  end,  generally  projecting — almost  as  if  it  were 
a  separate  structure — from  the  line  of  the  main  building.  When 
the  factory  is  two  storeys  high,  the  smoking  department  is  again 
usually  at  one  end  of  the  upper  storey,  the  rest  of  that  floor  being 
used  for  packing  and  weighing.  When  such  arrangements  are 
adopted,  the  smoke  is  obtained  by  various  methods,  the  simplest 
being  by  perforated  buckets  containing  the  smouldering  sub- 
stances. In  other  cases  the  smoke  and  hot  air  are  obtained  from 
furnaces  placed  outside  the  building. 

The  risks  from  fire  in  a  part  of  the  main  building,  especially 
when  smoking  is  carried  out  on  the  second  floor,  are  sometimes 
considerable.  In  a  private  catalogue  is  shown  the  division  of 
the  upper  storey  of  a  factory  erected  by  Cochrane.  The  drying 
and  smoking-room  is  supphed  with  smoke  as  described  in  a  previous 
chapter. 

Smoking-Houses. 
Some  managers  prefer  to  have  a  separate  building  wherein 
the  rubber  can  be  smoked  and  dried.  This  is  beheved  to  minimise 
fire  risks,  and  to  enable  the  managers  to  organise  the  rest  of  the 
factory  operations  more  economically.  The  disadvantage  is  the 
distance  which  such  a  building  is  usually  from  the  washing-mills 
and  packing  rooms.  Considerable  hand  labour  and  exposure  is 
involved  in  taking  the  freshly-coagulated  rubber  from  the  main 
factory  and  in  carrying  the  smoked  and  dried  rubber  to  the  weighing 
and  packing  rooms. 


PARA     RUBBER 


401 


In  a  type  of  smoking-house  built  by  Francis  Shaw  &  Co.,  tlie 
floor  is  about  6  feet  from  the  ground,  and  below  are  the  fires,  which 


ELEVATION,    PLAN    OF    LOWER    CHAMBER,    AND    SECTION   OF   SHAW  S 
SMOKING  HOUSE. 

are  enclosed  in  a  chamber  with  sides  sloping  in  towards  the  bottom. 
The  floor  boards  are  laid  with  open  joints  to  allow  the  air  and  smoke 
to  pass  through,  and  below  the  floor  are ,  smoke-distributing 
plates.     A  ventilator  is  fixed  in  the  roof  as  shown  above. 

Continuous  Treatment  in  Central  Factories. 

Having  now  described  the  separate  processes  of  coagulating, 
washing,  drying  and  smoking,  and  seen  how  much  time  and  factory 
organisation  is  necessary  in  connection  with  each  of  these  procesies, 
we  can  now  consider  other  aspects.  In  the  foregoing  chapters 
it  has  been  shown  how  independent  each  process  is  or  may  be 
of  the  other,  and  how,  in  the  event  of  one  section  failing  for  a 
short  time,  the  others  may  be  proceeding.  For  instance,  drying 
or  smoking,  or  both,  may  be  going  on  during  the  night  when  the 
others  are  stopped.  Similarly,  the  other  processes  may  be  going 
on  when  the  drying  and  srhoking  compartments  are  empty.  In 
many  instances,  rubber  is  washed  only,  or  is  cured  only,  for  a 
neighbouring  estate  not  fully  equipped  for  complete  preparation. 
There  is,  therefore,  usually  ample  provision  made  for  each  process 
in  factories  on  estates  in  an  advanced  stage.  In  some  instances 
it 'has  been  thought  possible  to  effect  economy  by  using  a  central 
factory  for  several  estates,  large  spaces  and  the  necessary  machinery 
and  apparatus  being  provided  for  each  process  in  the  preparation 
of  the  finished  product.  Such  a  system  may  make  each  participant 
very  dependent  on  the  successful  running  of  every  department 
of  such  a  factory,  though  it  is  obvious  that  economy  is  more 
possible  under  such  a  scheme  providing  everything  is  maintained 
in  perfect  working  order.     A  step  has  been  taken  in  this  direction 


402  PARA     RUBBER 

by  the  newly- formed  "Kajang  Curing  Company,"  that  has  been 
formed  with  the  object  of  curing,  in  a  central  factory,  the  rubber 
from  the  Inch  Kenneth,  Glenshiel,  Balgownie,  Cheras,  Kajang,  and 
Sungei  Parau  estates  in  Malay. 

A  System  for  Continuous  Treatment. 

Somewhat  allied  to  this  is  an  invention  taken  out  in  the  joint 
names  of  Da  Costa  and  Bridge  for  an  elaborate  installation  of 
apparatus  at  one  end  of  which  is  fed  the  latex  and  at  the  other 
is  turned  out  the  finished,  marketable  rubber.  From  a  receiving 
trough  the  latex  is  led  through  a  pipe  by  gravitation  or  by  pumping 
into  the  coagulating  tank  of  a  Da  Costa  Smoker  Coagulator.  In  this 
coagulation  is  brought  about  by  a  mixture  of  smoke  and  steam, 
or  by  one  of  smoke  mixed  with  heated  or  cold  air  driven  in  by 
an  air-compressor  or  drawn  through  by  a  blower,  etc.  The 
coagulated  rubber  may  be  conveyed  by  various  means  proposed 
{worm  conveyor,  vanewheel,  etc.)  to  one  or  a  series  of  pairs  of 
rollers — macerating,  creping,  or  sheeting — between  which  it 
passes  downwards  and  is  deposited  upon  an  endless  belt.  This 
carries  it  towards  a  table,  upon  which  it  may  be  cut  into,  say, 
sheets,  which  are  then  placed  within  a  heated  drying  chamber. 
In  this  chamber  may  be  a  number  of  endless  belts,  preferably 
of  lattice  work,  arranged  one  above  another,  and  the  rubber 
placed  upon  the  uppermost,  drops  from  one  to  the  other.  In  place 
of  the  series  of  belts,  a  single  conveyor  belt  may  be  used  in  the 
drying  chamber.  Instead  of  a  simple  drying  chamber,  a  vacuum 
chamber  can  be  employed.  Provision  for  surface-smoking  is 
possible.  After  drying,  the  rubber  may  be  prepared  as  sheet, 
crepe  or  blanket,  and  may  further  be  finished  as  block,  arrange- 
ments being  made  even  to  run  the  trolleys  carrying  the  rubber 
to  the  presses  directly  into  them  so  that  transference  is  unnecessary. 

This  process  may  strike  the  planter  as  imaginary ;  it  has 
the  merit  of  originality,  and  may  lead  to  practical  suggestions 
later. 

In  the  previous  chapter  on  the  drying  of  rubber,  page  389, 
a  full  description  of  a  continuous  system — the  Michie  Golledge — 
has  been  given. 


CHAPTER    XXVI. 

FORMS.     BRANDING,     PACKING,     AND     HANDLING 
OF    PLANTATION     RUBBER. 

In  the  foregoing  accounts  of  the  methods  of  preparing  planta- 
tion rubber  it  has  been  shown  that  the  finished  product  may  be 
presented  in  various  forms.  In  the  production  of  each  kind 
special  means  and  apparatus  are  employed  and  certain  general 
rules  followed  in  order  to  meet  market  requirements.  The 
principal  form  of  plantation  rubber — in  first-quality  grades — 
now  on  the  market  are  :  biscuits,  sheet,  crepe,  worms,  and  block 
(scrap  being  in  the  form  of  crepe,,  slabs,  or  blocks).  All  except 
crepe  and,  perhaps,  block  rubber  may  appear  in  the  smoked 
or  unsmoked  condition. 

Merchants  have  aided  the  standardization  of  plantation 
grades  by  contracting,  in  forward  sales,  for  rubber  in  the  form 
of  (i)  smoked  or  unsmoked  sheet,  (2)  crepe,  not  smoked,  (3)  block, 
(4)  scrap.  Forward  contracts  have  been  made  for  1912  and  1913 
in  which  plantation  rubber  may  be  delivered  in  the  form'  of  crepe 
or  sheet  at  the  option  of  the  sellers.  This  may  suggest  that  the 
two  forms  are  approximately  of  the  same  value. 

Biscuit   Rubber. 

Biscuit  rubber,  the  original  form  of  preparation  in  Ceylon, 
is  now  not  so  commonly  met  with,  as  most  estates  have  machinery 
installed  for  turning  out  other  forms.  It  is  prepared  by  allowing 
the  latex  to  set  in  shallow,  circular  receptacles  after  acetic  acid 
has  been  added,  and  by  washing  and  rolling  the  cake  of  rubber  that 
appears  at  the  top.  The  biscuits  are,  therefore,  more  or  less 
circular  in  outline. 

In  many  instances  they  curl  up  at  the  edges  on  drying  and 
present  an  objectionable  appearance.  This  can  to  some  extent 
be  overcome  by  pressing  them  in  a  vessel  of  definite  outhne 
before  subjecting  them  to  the  rolling  process.  After  rolling,  the 
cakes  partake  of  the  shape  of  the  vessel  in  which  they  have  been 
pressed.  If  the  margins  of  the  coagulating  receptacles  are 
correctly  made,  the  tendency  to  curl  and  become  wavy  in  outhne 
is  not  so  noticeable. 

Biscuits  (and  sheets)  are  usually  very  pure,  and  can,  without 
washing,  be  used  for  ' '  solution ' '  work  by  the  manufacturers  ;  the 
material  is  practically  ready  for  the  naphtha  bath  on  its  arrival  in 
Europe.  It  has  been  stated  that  the  material  from  Ceylon  shrinks 
about  i'4  per  cent.,  and  that  it  is  not  hked  for  cements.  In  past 
times  it  has  been  very  irregular  in  quality,  sometimes  being  little 


404  PARA     RUBBER 

better  than  elastic  gum,  sometimes  sticky  and  only  equal  to 
recovered  rubber  in  elasticity.  The  rubber  biscuits  from  old  Hevea 
trees  are  tough  and  elastic,  and  much  of  the  irregularity  referred 
to  might  to  some  extent  be  obviated  by  not  mixing  the  tappings 
from  trees  of  different  ages. 

Biscuits  are  made  from  ,',;  to  J  inch  in  thickness  and  lo  to 
14  inches  in  diameter. 

Sheet    Rubber. 

This  is  prepared  by  coagulating  the  latex  in  special  oblong 
dishes  and  passing  the  rubber  between  smooth  rollers  running  at 
even  speeds  or  at  a  very  low  differential  rate.  Sheet  rubber  does  not 
get  the  thorough  washing  that  crepe  receives,  though  it  has  the 
advantage  of  being  less  worked  mechanically.  It  is  generally 
admitted  that  plantation  sheet  finished  in  the  machine  by  a 
squeezing  as  opposed  to  a  tearing  or  disintegrating  action,  in- 
volved in  making  crepe,  has,  so  far  as  manufacturing  experience 
goes,  given  the  most  satisfactory  results. 

It  is  considered  a  great  improvement  to  run  the  sheet  finally 
between  diamond-cut  rollers,  or  other  patterns.  The  resultant 
ridging  of  the  surface  allows  for  ventilation  between  the  sheets, 
so  that  mould  develops  less  easily.  It  also  prevents  them  sticking 
together  to  any 'extent.  This  form  of  rubber  is  verv  frequentlv 
smoked  on  the  plantation. 

Sheets  measuring  at  least  24  by  12  inches  and  one-sixteenth 
to  one-eighth  in  thickness  are  received  with  favour  in  Europe. 

Crepe  Rubber. 

Crepe  rubber  differs  from  the  foregoing  on  account  of  the 
stretching  and  tearing  it  has  undergone  between  the  rollers  of  the 
washing  machine  and  the  low  quantity  of  soluble  and  mechanical 
impurities  it  contains.  It  is,  of  course,  only  washed  rubber,  but 
it  may  have  been  obtained  from  purified  scrap  as  well  as  the  other 
class.  It  has  an  irregular  surface,  is  uneven  in  thickness,  and 
like  lace  and  flake  rubber,  dries  very  rapidly.  On  account  of  its 
purity  it  has  been  well  reported  upon  in  Europe. 

Lewis  and  Peat  stated  in  1905  that  ' '  manufacturers  are  still 
prejudiced  against  any  rubber  that  has  been  washed  or  otherwise 
treated,  as  a  certain  amount  of  the  natural  fibre  and  elasticity  is 
lost  in  the  process,  and  the  true  quahty  of  the  rubber  is  much 
more  difficult  to  tell  in  this  form  ;  but  the  prejudice  seems  to  be 
wearing  off."  That  the  prejudice  has  worn  off  is  witnessed  by  the 
free  and  considerable  market  in  crepe.  In  their  circular  for  igio, 
in  addition  to  smoked  sheet,  the  same  firm  recommend  the  pre- 
paration of  fine,  thick,  gristly  blanket  crepe. 

Crepe  rubber  may  be  prepared  in  lengths  of  from  3  to  9  feet, 
width  about  12  inches,  and  be  graded  according  to  colour.  To 
the  thicker  preparations  the  term  "blanket  crepe"  has  been 
applied.  Messrs.  Gow,  Wilson  &  Stanton,  in  their  report  for  1910, 
noted  a  marked  tendency  to  roll  out  crepe  very  thin  to  hasten 


Photo  by  Ivor  Ethermgton. 


DRYING      BISCUIT      RUBBER 


Phntn  hji  C.  H.  Ken: 


PREPARATION    OF     BISCUITS. 


PARA     RUBBER  405 

drying,  and  remarked  that  it  was  desirable  that  crepe  in  the 
finished  form  should  be  thick  and  even  in  texture,  say  |  in.  thick, 
prepared  by  running  together  between  the  rollers  several  layers 
of  thin  crepe.  It  is  a  mistake  to  attempt  to  turn  out  thick  crepe 
in  one  operation. 

Worm   Rubber. 

Worm  rubber  is  essentially  the  product  obtained  by  cutting 
irregular  sheets  of  freshly-coagulated  rubber  into  thin  worm-like 
rods  of  unequal  length.  This  form  comes  from  Ceylon,  the  Michie- 
Golledge  machine  being  used  to  coagulate  the  latex.  The  fresh 
rubber  is  rolled  to  express  the  water,  and  the  irregular  cakes  are 
cut  into  "worms"  by  means  of  large  shears  or  machines.  The 
fresh  rubber,  being  cut  into  such  fine  parts,  dries  quickly.  The 
' '  worms ' '  can  be  economically  packed  in  ordinary  tea  boxes. 

By  passing  the  dry  worms  through  ordinary  washing-rollers 
they  are  bound  togetlier  into  a  characteristic  form. 

Samples  of  "worm"  rubber  have,  up  to  the  present,  received 
good  reports,  the  concensus  of  opinion  being  that  the  rubber 
so  prepared  is  very  clean  and  contains  very  little  rnoisture. 

Lace  Rubber. 

Lace  rubber  was  for  a  time  prepared  by  Holloway  in  Ceylon. 
It  consisted  of  very  thin  perforated  sheets  of  considerable  length. 
The  porous  sheet  was  very  thin,  of  a  pale  amber  colour,  and  was 
easily  pressed  into  biscuits  or  sheets  of  any  desired  thickness. 
The  ' '  lace ' '  came  out  of  the  machine  in  a  continuous  strip,  and 
was  cut  into  pieces  6  feet  long  as  it  ran  on  to  wire  trays.  It  was 
maintained  that  it  could  be  turned  out  ready  for  drying  within 
seven  minutes  of  the  arrival  of  the  latex  at  the  factory.  The 
tiriie  taken  for  coagulating  the  latex,  conversion  into  lace  rubber, 
and  drying  ready  for  despatch  was  stated  to  be  48  hours. 

Flake  Rubber. 

Flake  rubber  was  first  made  by  Mr.  C.  O.  Macadam,  Culloden, 
Neboda.  It  was  prepared  by  placing  small  pieces  of  freshly- 
coagulated  rubber  in  a  small  rolling  machine  or  washer,  the 
corrugations  of  which  ran  horizontally.  The  rollers  were  close 
together,  and  the  cut  rubber  issued  as  thin  strips.  The  strips 
or  flakes  were  thin,  and  could  be  easily  smoked  and  packed  in 
any  form.  The  sample  I  saw  was  pale  amber  in  colour,  free 
from  mechanical  impurities,  and  possessed  good  physical  properties. 
It  is  apparent  that  the  very  thin  flakes  can  be  rapidly  dried,  and  in 
this  respect  compare  very  favourably  with  crepe  or  lace  rubber. 
This  form  is  seldom  seen  on  the  home  market ;  the  same  remark 
applies  to  ' '  lace ' '  rubber. 

Scrap  Rubber. 

Scrap  rubber  is  mainly  the  coagulated  rubber  obtained  from 
the  collecting  cups,  tapping  utensils,  and  incised  areas,  rolled 
into  balls  or  made  up  into  cakes.     It  may  be  sent  to  Europe  in 


4o6  PARA     RUBBER 

the  crude  state,  with  all  its  mechanical  impurities,  or  washed, 
purified,  and  converted  into  crepe  rubber  before  being  despatched. 
Scrap  rubber,  if  free  from  bark,  dirt,  and  other  impurities,  obtains 
a  high  price.  Hand-picked  scrap  is  preferred  to  the  washed 
material  by  some  buyers. 

Having  regard  to  the  opinions  of  manufacturers  as  to  the 
desirabihty  of  securing  dry  pure  rubber  in  preference  to  wet, 
and  bearing  in  mind  the  objections  which  others  raise  against 
the  use  of  machinery  in  the  preparation  of  crepe,  the  ' '  India- Rubber 
Journal"  asked  manufacturers  whether  they  preferred  scrap 
rubber  to  be  sent  as  purified  scrap,  crepe- or  block,  instead  of  in 
the  usual  impure  form  containing  a  large  proportion  of  water, 
bark  and  other  mechanical  impurities.  Only  one  firm  suggested 
that  the  scrap  should  be  sent  in  the  condition  in  which  it  arrives 
at  the  plantation  factory.  All  the  other  firms  agreed  that  the 
purification  of  scrap  rubber  was  a  thing  to  be  desired,  and  are 
thus  consistent  in  their  demands  for  pure  dry  rubber  of  the  first 
grade. 

Block   Rubber. 

It  is  well  known  that  block  rubber  has  been  most  successfully 
prepared  on  Lanadron  Estate,  Johore.  I  have,  in  my  office, 
exposed  to  light,  dust  and  various  temperatures  for  over  five  years, 
two  blocks  of  first-grade  and  scrap  block  rubber  made  on  Lanadron 
by  Mr.  Francis  Pears.  They  appear  to  be  just  as  good  as  when 
originally  received.  It  is  obvious  that  when  rubber  is  made  into 
six-inch  blocks  weighing  25  lb.  to  50  lb.  they  are  hkely  to  be  com- 
paratively uniform  in  section  and  to  expose  the  minimum  surface 
to  air  and  light.  These  advantages,  together  with  the  ease  of 
manufacture  and  packing,  are  such  as  to  make  this  form  one  of  the 
most  desirable. 

Block  rubber  is  usually  made  by  placing  the  soft  pliable  crepe 
from  the  vacuum  drier  into  presses:  When  rubber  leaves  the 
vacuum  chamber  it  is  of  a  consistency  which  permits  of  easy 
handling  and  pressing  into  any  shape  ;  on  cooling,  the  rubber 
hardens  and  retains  the  shape  of  the  receptacle  in  which  it  has 
been  pressed  while  cooling. 

Block  rubber  may  also  be  made  from  biscuits,  sheets,  scrap, 
or  worm  rubber  by  pressing  the  material  while  in  the  soft  condition 
as  it  is  when  removed  from  the  heated  vacuum  chamber,  or  by 
pressing  freshly-coagulated  wet  rubber.  The  blocks  may  be  made 
into  cubes  or  rectangular  slabs  and  in  all  cases  present  only  a 
relatively  small  surface  to  air  and  hght. 

Owing  to  the  arrival  of  parcels  of  wet  block,  many  manu- 
facturers have  shown  a  disinclination  to  purchase  rubber  in  this 
form.  Many  of  them  have  gone  back  to  the  old  form  of  sheets  or 
the  later  form  of  crepe. 

A  Recent  Opinion  upon  Block. 
Interviewed    during    the    course    of    the    1911    Exhibition, 
Schidrowitz  remarked  that,  with  regard  to  block,  it  seemed  that 


PARA     RUBBER  407 

no  particular  progress  had  been  made.  Manufacturers  perhaps 
found  it  an  awkward  form  ;  they  usually  preferred  a  method  of 
preparation  which  would  enable  them  to  detect  impurities  im- 
mediately. On  the  other  hand,  there  was  at  least  one  mark  of 
block  for  which  manufacturers  had  a  regard,  and  in  this  case  the 
quality  was  always  so  uniformly  high  that  it  could  be  purchased 
without  risk.  He  thought  that  when  one  had  a  sufficiently  hard 
rubber  to  stand  the  heating  in  the  blocking  press  necessary  for 
perfect  block,  and  very  efficient  superintendence,  block  could  not 
be  beaten.  He  looks  upon  block  made  by  compressing  smoked 
crepe  as  the  ideal  form ;    crepe  is  not,  however,  generally  smoked. 

Size  of  Blocks. 

The  original  Lanadron  blocks  were  about  10  by  10  by  6  inches. 
Mr.  Francis  Pears  advocated  the  preparation  of  blocks  about  one 
cubic  foot  in  size,  so  that  two  could  go  to  a  case,  with  a  thin 
partition  between  them.  Such  a  block  would  weigh  about  50  lb., 
and  would  therefore  be  equivalent  to  about  200  biscuits.  The 
reasons  which  Mr.  Francis  Pears  gave  in  support  of  the  idea  of 
making  such  large  blocks  were  (i)  the  thinner  the  blocks,  the 
more  the  hydraulic  presses  required,  or  less  time  must  be  given  to 
pressing  each  block  ;  and  (2)  several  thin  blocks  or  slabs  packed  in 
one  case  would  be  firmly  stuck  together  on  arrival  in  Europe  and 
would  require  considerable  effort  to  separate  them.  Several 
London  firms,  however,  have  suggested  that  the  blocks  should  not 
be  so  thick  and  state  that  rectangular  slabs  would  be  welcome. 
The  thinner  blocks  are  handled  with  more  ease. 

Many  persons  prefer  thin  block,  say,  from  i  to  ij  inches  thick, 
that  can  be  taken  by  the  washing  or  mixing  machine  without 
being,  previously  cut  up.  It  is  admitted  that  making  blocks  so 
thin  is  a  nuisance  ;  it  may  be  better  to  make  them  large  and  cut 
them  into  sections  on  the  plantation. 

It  has  been  asserted  by  a  manufacturer  that  blocks  12  in.  by 
12  in.  by  2  in.  are  convenient  for  packing  and  in  every  way  suited 
to  the  requirements  of  most  manufacturers. 

One  may  note  that  thin  blocks  or  slabs  can  be  tested  for 
impurities  by  holding  up  to  the  light. 

Blocking  Dry  Rubber. 

Block  rubber,  of  a  kind,  can  be  made  by  pressing  freshly- 
coagulated  rubber,  or  the  partially  dry  and  soft  rubber  fresh  from 
the  vacuum  driers  ;  but  it  is  also  possible  to  make  a  block  by  press- 
ing biscuits  which  have  been  kept  in  the  dried  state  for  several 
months.  On  one  occasion  some  biscuits,  ten  weeks  old  and  per- 
fectly dry,  were  placed  in  a  rnould  and  subjected  to  enormous 
pressure  in  a  large  hand-screw  press  ;  the  pressed  biscuits  were 
kept  in  this  condition  for  two  nights  and  one  day — 36  hours  in  all — 
and  then  removed  ;  the  block  was  fairly  good,  all  traces  of  the 
separate  biscuits  being  superficially  destroyed  and  only  feebly 
distinguishable  when  the  block  was  cut  in  two.     If  the  dry  rubber 


408  PARA     RUBBER 

is  passed  through  heated  rollers  it  is  softened  and  in  a  condition 
fit  to  be  blocked. 

Presses  for  Blocking  Rubber. 
Freshly-toagulated  rubber  is  soft  and  spongy  and  can  be 
blocked  without  the  use  of  comphcated  machinery.  On  some 
small  properties  a  letter  press  has  been  effectively  used  in  the 
preparation  of  small  samples  of  slab  or  block  rubber,  but  on 
estates  where  the  daily  output  is  at  all  large,  the  use  of  a  press  is 
essential  for  blocking  rubber.  The  presses  first  brought  before 
the  planters  were  usually  so  constructed  as  to  be  capable  of  being 
worked  by  hand  or  power,  and  a  large  number  have  already  been 
found  to  be  very  defective  when  required  to  give  a  pressure  equal 
to  one  or  two  tons  per  square  inch.  The  use  of  hydraulic 
presses  is  generally  viewed  with  favour  and  already  machinery  of 
this  type  has  been  placed  on  the  market.  Presses  of  various 
types  have  been  tried  and  a  description  of  some  of  these  will  not 
be  out  of  place. 

Shaw's  Blocking-Press. 

Messrs.  Francis  Shaw  and  Co.  have  placed  on  the  market 
a  compact  hydraulic  press.  It  is  claimed  that,  in  their  press, 
there  are  no  working  parts  liable  to  get  out  of  order,  which  is  a 
great  consideration  when  the  native  labour  usually  employed  is 
taken  into  account.  The  top  is  hinged  for  charging  and  emptjning, 
and  can  be  arranged  to  produce  any  size  of  finished  block.  Name 
plates  are  supplied  to  fit  the  cavities  by  means  of  which  the  name 
of  the  plantation  is  impressed  on  each  block  of  rubber  produced. 
The  press  is  operated  by  a  small  hand  pump,  fitted  with  a  safety 
valve  which  allows  the  water  to  circulate  as  soon  as  the  required 
pressure  is  attained  in  the  press.  For  smaller  plants  machines  of 
smaller  construction  and  made  for  driving  either  from  line  shafting 
near  the  floor- level,  or  by  means  of  belting  from  overhead  shafting, 
are  supplied.  The  blocks  are  made  to  any  size,  but  12  by  12  by  ij 
inches  seems  to  be  preferred  by  them. 

David   Bridge's   Presses. 

Messrs.  David  Bridge  and  Co.  have  designed  a  blocking-press 
which  can  be  worked  by  hand  or  otherwise.  It  consists  of  a  screw 
fitted  with  a  machine-cut  worm  wheel,  driven  by  a  steel-cut  worm 
by  fast  and  loose  pulleys.  A  reversing  motion  is  arranged  for  the 
quick  withdrawal  of  the  platten.  This  is  carried  on  two  strong 
steel  columns,  bolted  to  the  base.  The  platten  proper  has  a 
detachable  platten  cottered  to  it,  on  which  are  letters  for  branding 
the  block  rubber.  The  box  is  detachable,  therefore  any  number 
of  boxes  can  be  used  with  the  one  press.  Each  box  is  fitted  with 
two  strong  wrought-iron  bridles,  with  four  powerful  screws.  After 
the  crepe  rubber  has  left  the  vacuum-dryer  it  is  pressed  in  the 
bjox,  and  when  under  pressure  the  bridles  are  brought  over  to  an 
upright  position.  The  bottom  of  the  box  is  hinged  and  allows  the 
block  to  be  forced  out  by  four  vertical  screws. 


PARA     RUBBER  409 

This  press  is  also  fitted  with  a  hand  motion,  which  is  quite 
satisfactory  in  the  absence  of  mechanical  power.  The  power 
required  to  drive  by  belt  is  from  2  to  3  H.P.  The  boxes  are  of 
different  sizes.  The  total  weight  of  this  press  is  about  17  cwt., 
with  one  box. 

The  same  firm  has  patented  a  hydraulic  block-press  which 
appears  to  be  useful  for  blocking  rubber.  By  the  use  of  hydraulic 
pressure,  a  known  total  pressure  can  be  put  upon  the  rubber  being 
pressed,  and  the  pressure  can  be  regulated  exactly  in  accordance 
with  requirements. 

The  machine  consists  of  a  hydraulic  cast-iron  ram,  fitted  into  a 
strong  hydraulic  cylinder,  with  U  leather  packing  arranged  to  work 
at  a  pressure  of  1,200  lb.  per  square  inch.  The  base  of  the  cylinder 
is  arranged  to  carry  an  improved  design  hydraulic  pump,  operated 
by  hand-lever,  with  relief  valve  and  hydraulic  pressure-gauge. 

A  strong  cast-iron  rising  table  is  fitted  upon  the  top  of  the 
ram,  and  an  extra  strong  cast-iron  head,  fitted  with  lifting  eye 
and  mullet  or  ram  of  sufficient  length,  secured  to  same  to  admit 
of  its  passing  into  the  box  when  placed  on  the  table,  and  so  press 
the  rubber  to  the  necessary  thickness.  The  cast-iron  head  is 
supported  by  four  turned  steel  pillars,  secured  by  hexagonal  nuts  to 
the  head  and  cylinder  mentioned. 

The  table  is  arranged  to  receive  interchangeable  boxes  14  in. 
by  12  in.  by  9  in.,  which  are  fitted  with  runners  on  rails  secured 
to  the  pillars,  and  quickly  run  away  to  any  part  of  the  works. 
Each  box  is  arranged  to  run  on  wheels,  and  fitted  with  two  strong 
wrought-iron  bridles,  with  four  powerful  screws. 

Comparison  of  Present  Plantation  Forms. 

The  various  forms  which  have  been  here  described  have  now 
been  known  to  manufacturers  for  several  years,  and  the  advantages 
and  disadvantages  of  each  pubHcly  discussed  on  several  occasions. 

The  "India- Rubber  Journal"  published  the  views  of  manu- 
facturers on  this  subject  in  the  latter  part  of  1907,  and  pointed  out 
that  though-the  experimental  phase  in  the  preparation  of  rubber 
in  various  fancy  forms  was  almost  past,  and  crepe,  sheet,  block, 
and  biscuit  were  the  predominating  types  on  the  London  market, 
yet  the  original  biscuits  still  appealed  to  certain  manufacturers, 
apparently  because  they  could  be  easily  examined  to  ascertain 
their  purity  ;  sheet  similarly  appealed  to  many  manufacturers  in 
virtue  of  its  purity  and  the  fact  that  it  had  not  been  subjected  to 
any  mechanical  treatment.  At  the  present  moment  the  demand 
is  mainly  for  thick,  blanket  crepe  or  clean,  smoked  sheet. 

As  far  as  the  producer  is  concerned,  biscuits  and  sheets  are 
prepared  in  the  same  manner  and  at  the  same  cost,  but  the  rec- 
tangular form  is  preferred  for  convenience  in  packing.  Biscuits 
and  sheets,  owing  to  the  very  long  time  required  to  effectively 
dry  them,  are  not  popular,  except  on  small  estates.  To  the  planter 
there  is  another  strong  objection  to  biscuits  and  sheets  :  they  must 
generally  be  prepared  in  small  pans  by  the  slow-setting  process. 


410  PARA     RUBBER 

requiring  big  factory  space  and  a  waiting  period  of  over  twelve 
hours,  whereas  the  whole  of  the  day's  latex  can  be  converted 
into  rubber  in  one  receptacle  in  the  space  of  a  few  minutes.  The 
manufacturers  who  still  prefer  biscuits  request  that  these  pan- 
cakes be  as  thin  as  possible.  Those  who  prefer  plantation  rubber 
in  the  form  of  sheets  specify  that  the  sheets  should  be  fairly  thin  ; 
one  firm  also  suggests  that  they  should  be  from  two  to  three 
feet  wide  by  two  to  three  yards  long. 

Branding  of  Plantation  Rubber. 

Manufacturers  have  strongly  advised  planters  to  brand  all 
their  rubbers.  They  demand,  and  planters  have  every  reason 
to  respect  their  request,  that  plantation  rubber  must  not  be 
variable  in  appearance,  composition,  or  physical  properties.  They 
advocate  branding  the  rubber  from  ev-ery  estate,  because  this  is 
the  only  way  in  which  they  can  overcome  the  difficulties  consequent 
on  the  acknowledged  variability  of  plantation  rubber.  First- 
quahty  rubber  from  one  estate  known  to  the  manufacturer  by  its 
mark  is  bought  and  used  by  the  same  firm  for  the  same  purpose 
time  after  time.  There  is  less  variabihty  in  first-grade  qualities 
from  one  estate  than  from  several  plantations,  and  if  the  manufac- 
turer cannot  get  his  rubber  from  a  plantation  the  mark  of 
which  is  already  known  in  his  works,  there  is  bound  to  be  confusion 
and  trouble  in  the  near  future.  Several  plantation  companies  have 
already  made  their  name,  and  their  mark  is  a  guarantee  of  quality 
and  uniformity  to  manufacturers  ;  there  will  be  less  difficulty 
in  disposing  of  the  produce  from  such  estates  than  from  properties 
without  a  name  or  reputation. 

At  present,  speaking  generally,  block,  sheet,  and  biscuits 
are  marked,  but  in  the  case  of  crepe,  scrap  and  other  forms,  the 
mark  is  usually  only  on  the  packing  case.  Block  rubber  may 
readily  be  impressed  with  the  necessary  mark  on  one  or  both 
surfaces  in  the  process  of  blocking.  Biscuits  and  sheets  are 
stamped  before  they  are  dry,  and  when  the  rubber  almost  resembles 
dough.  With  crepe  it  is  different,  because  when  it  comes  out  of 
the  machine  it  is  hard,  and  therefore  very  difficult  to  make  an 
impression  upon.  Yet  it  is  stated  that  it  may  be  distinctly 
marked  by  being  passed  between  metal  rollers,  on  one  side  of 
which  the  desired  mark  or  name  has  been  cut.  The  marking  of 
the  packing  cases  alone  is  as  hkely  to  aid  as  to  prevent  fraud. 

A  branding  press  for  sheets,  biscuits,  etc.,  has  been  put  on  the 
market  by  Messrs.  Shaw  &  Co. 

Proposed  Gradixc,  of  Plantation  Rubber. 

A  suggestion  has  been  made  that  plantation  rubber  should 
be  graded  as  No.  i.  No.  2,  and  No.  3  latex,  and  be  sold  as  such 
without  the  estate  being  specified.  The  object  is  to  enable  forward 
sales  to  be  made.  This  will,  it  is  mantained,  if  successful,  tend  to 
class  all  sheets,  crepe,  etc.,  as  of  one  value.  If  manufacturers 
are  going  to  use  plantation  rubber  as  fast  as  it  is  produced,  it 


PARA     RUBBER  411 

is  absolutely  necessary  for  them  to  know  what  they  are  getting 
when  they  buy,  so  far  as  high  qualities  are  concerned.  At  present 
they  can  specify  marks  for  which  they  are  willing  to  pay  a  premium  ; 
but,  if  in  the  future  they  can  only  buy  No.  i  latex,  they  will  not 
know  exactly  what  they  are  getting,  as  any  lot  of  this  grade  may 
include  the  produce  from  a  number  of  estates. 

Packing   of    Rubbkr. 

In  packing  plantation  rubber,  the  cases  should  be  strong  and 
well  hooped.  When,  as  happens  sometimes  in  Ceylon,  the  rubber 
is  sent  to  the  shipping-port  packed  in  weak  tea-chests,  it  should  be 
repacked  in  stronger  cases.  This  is  not  always  done,  and  there 
are  serious  complaints  of  exposure  of  the  rubber  to  deteriorating 
influences  through  breakage  of  the  cases.  It  is  of  interest  to 
know  that  most  of  the  rubber  shipped  from  Para  is  put  into  cases 
made  of  imported  American  pinewood.  The  inside  of  the  cases 
should  be  perfectly  clean,  smooth,  and  free  from  sawdust  and 
splinters.  Lining  with  paper  or  cloth  or  dusting  with  fuller's 
earth  is  undesirable. 

Sheet  and  crepe  should  be  packed  flat  and  folded  to  fit  the 
usual  size  of  case.  It  is  not  advisable  to  roll  sheet  and  crepe  for 
purposes  of  packing,  though  a  few  estates  do  so. 

Shape   and   Weight   of   Cases. 

The  shape  of  packing-case  that  undergoes  handling  the  most 
satisfactorily  is  that  which  is  almost  cubical ;  the  measurements  of 
a  typical  case  are  19  by  19  by  24  inches.  Oblong  cases  seem 
generally  to  fall  to  pieces,  and  on  arrival  at  the  wharf  may  be  found 
tinkered  up  with  odd  pieces  of  wood.  A  case  of  the  above  size  will 
weigh  about  20  lb.  It  is  the  practice  on  some  estates  to  enclose 
the  case  in  gunny,  which  renders  the  detection  of  pilfering  simple. 
Another  provision  against  pilfering  is  to  use  wooden  instead  of 
steel  hoops. 

The  Ventilation  of  Cases. 
The  desirability  of  ventilating  cases  in  which  plantation 
rubber  is  shipped  appears  to  be  questionable.  Some  manu- 
facturers have  suggested  that  planters  should  ship  their  rubber  in 
air-tight  cases,  but,  on  the  other  hand,  a  few  planters  have  had 
cause  to  regret  having  adopted  that  system,  owing  to  the  arrival 
of  their  rubber  in  Europe  in  a  heated  condition.  It  is  obvious  that 
block  rubber  has  an  advantage  over  sheet  and  crepe  in  so  far  that 
proportionately  less  surface  is  exposed  to  the  air  ;  one  might, 
therefore,  feel  inchned  to  argue  that  packing  in  air-tight  cases,  to 
minimise  oxidation,  would  be  advantageous.  But  one  must 
realize  that  it  is  impossible  to  ship  rubber  in  vacuum  cases  ;  air 
must  always  be  present.  To  lock  up  rubber  in  an  air-tight  case 
may  simply  result  in  imprisoning  foul  gases  during  transit,  and  if 
there  is  any  tendency  towards  tackiness  at  the  time  of  packing  the 
.  whole  consignment  may  arrive  as  a  treacly  mass. 


412  PARA     RUBBER 

Bearing  upon  this  point  is  the  history  of  samples  of  rubber 
that  were  taken  from  block  rubber  prepared  on  the  Lanadron 
Estate,  and  were  carried  about  by  Mr.  Jas.  Ryan  for  two  and  a 
half  years.  One  that  was  allowed  to  remain  loose  in  a  kit-bag  or 
suit-case,  seldom  being  wrapped  even  in  paper,  retained  all  its 
qualities.  The  other,  fixed  to  the  lid  of  an  air-tight  metal  case, 
began  to  degenerate  within  three  weeks  and  became  hopelessly 
tacky. 

Fractions    of   a    Pound. 

The  exact  weight  of  rubber  in  each  packing  case  is  also  a 
point  worth  considering.  Fractions  of  a  pound  of  rubber  in  a 
case  are  always  in  favour  of  the  buyer,  no  allowance  being  made 
for  such  to  the  seller.  It  would  therefore  appear  to  be  advan- 
tageous to  the  seller  to  carefully  weigh  the  cases  before  shipment, 
and  after  allowing  for  the  average  loss  in  weight  during  transit, 
to  add  a  few  ounces  of  rubber  in  excess  of  the  full  pound.  It  is 
obviously  better  for  the  seller  to  receive  payment  for  200  lb.  and 
ose  the  value  of  two  or  three  ounces  in  excess,  than  to  receive 
credit  for  only  199  lb.  and  lose  the  value  of  twelve  or  fifteen 
ounces  through  a  deficiency  of  a  few  ounces  below  a  full  pound. 
A  wharfinger  to  whom  this  idea  was  suggested  gave  it  as  his 
opinion  that  it  would  be  almost  an  impossibility  for  the  shipper  or 
packer  to  put  in  the  few  odd  ounces  suggested.  Practically  all 
rubber  loses  a  certain  amount  of  weight  between  the  time  of 
shipment  and  arrival  at  its  destination.  These  losses  vary  very 
much  according  to  the  description  and  quality  of  the  rubber,  and 
though  as  a  rule  with  most  estate  rubber  the  loss  is  fairly  regular, 
it  would,  in  his  opinion,  be  impossible  to  calculate  it  to  such  a  fine 
point  as  would  be  required  by  my  suggestion. 

Sorting  During  Packing  on  the  Estate. 

It  is  very  important  that  the  lots  sent  home  be  uniform  in 
quality  and  not  of  a  mixed  character,  and  though,  on  the  other 
hand,  subdivision  into  very  small  lots  is  a  disadvantage,  this  is  a 
less  important  consideration.  Lower  prices  result  if  there  is  want 
of  uniformity  either  in  individual  packages  or  in  lots.  Different 
colours  should  be  kept  separate,  and,  where  it  is  practicable, 
rubbers  from  trees  of  different  ages.  All  mottled  or  otherwise 
damaged  pieces  should  be  kept  together  in  a  separate  lot.  Where 
efficient  sorting  of  the  rubber  results  in  smallness  of  lots  at  any 
time,  the  best  plan  is  to  accumulate  the  particular  grades  until 
they  are  sufficiently  large  in  quantity  to  be  marketable.  As  a 
matter  of  fact,  rubber  deh\ered  against  a  forward  contract 
(London)  must  be  presented  in  lots  each  of  not  less  than  ten  tons. 

It  will  amply  repay  planters  to  grade  their  rubber  better 
than  they  have  done  in  the  past.  This  point  is  one  which  brokers, 
too,  might  bear  in  mind,  as  we  have  reason  to  beheve  that  more 
care  might  be  bestowed  by  them  in  the  offering  of  rubber  of 
variable  colour  in  the  same  lot.  In  the  past  brokers  have  some- 
-times  been  able  to  obtain  small  premiums  for  a  difference  in  colour. 


PARA     RUBBER  415 

and  in  such  cases  every  care  has  been  taken  to  keep  the  colour- 
grades  separate  ;  now,  and  in  the  future,  when  premiums  for 
novelties  in  colour  and  thickness  cannot  be  obtained,  there  may 
be  a  tendency  to  offer  lots  of  a  mixed  character — a  course  which 
is  obviously  likely  to  do  considerable  harm  to  the  grower. 

Packing   of   Tacky    Rubber. 

It  is  most  necessary  to  isolate  all  rubber  as  soon  as  symptoms 
of  tackiness  are  presented,  otherwise  the  condition  may  spread 
and  affect  large  quantities  of  rubber  in  the  factory.  Dipping 
tacky  rubber  in  a  2%  solution  of  formalin  is  said  to  check  the 
spread.  All  tacky  rubber  should  be  sold  as  soon  as  possible,  and 
not  be  allowed  to  accumulate  in  the  factory.  In'  packing,  care 
should  be  taken  to  remove  any  samples  of  rubber  presenting 
sticky  surfaces  or  spots.  All  such  material  should  be  packed  in 
separate  cases. 

Small  Lots  of  Rubber. 

Representations  have  been  made  regarding  the  difficulties 
which  some  brokers  experience  in  disposing  of  small,  classified 
lots  of  rubber  frequently  received  from  individual  estates  in  the 
Federated  Malay  States  and  Ceylon.  Planters  appear  to  be  very 
anxious  to  keep  all  grades  in  separate  packets,  a  principle  which 
should  be  continued,  and  against  which  no  objection  can  reason- 
ably be  made.  But  it  is,  in  the  sale  room,  very  difficult  to  provide 
space  for,  and  to  dispose  of,  very  small  quantities  of  graded 
rubber  to  the  best  advantage  as  separate  lots,  and  before  long 
it  is  anticipated  that  brokers  will  be  compelled  to  sell  such  con- 
signments, from  each  estate,  as  one  lot  or  accumulate  small 
lots  until  they  have  about  i  cwt.  of  each  grade.  In  one  instance 
there  were  no  less  than  six  grades  in  a  consignment  from  one  estate 
though  the  total  weight  was  only  ij  cwt.  Up  to  the  present  time 
many  brokers  have  been  able  to  dispose  of  their  small  lots  in 
separate  batches,  according  to  grades,  but  when  numerous  estates 
begin  to  tap  their  rubber  trees  the  difficulty  may,  especially 
during  the  next  couple  of  years,  become  a  very  serious  one.  It  has 
been  suggested  by  some  brokers  that  planters  would  be  acting 
wisely  if  they  agreed  to  the  sale  of  their  small  lots  as  one  lot ;  it 
would  certainly  be  to  the  convenience  of  brokers  and  buyers.  Each 
small  lot  could  be  packed  separately,  according  to  quality,  and 
these  placed  in  one  box  without  any  difficulty. 

It  is  generally  desirable  to  keep  back  the  lots  until  there  are 
2  or  3  cwt.  of  each  ready  for  shipment. 

Rubber  in  the  Wharves. 

A  statement  is  necessary  regarding  the  treatment  to  which 
rubber  is  subjected  on  arrival  at,  and  while  stored  in,  the  London 
wharves. 

The  cases  of  rubber  are  lightered  up  from  the  import  ships 
to  the  quays  of  the  various  warehouses,  and  are  immediately 
deposited  on  the  floor  of  the  warehouse,  the  latter  having  certain 


414  PARA     RUBBER 

floors  set  apart  for  the  purpose.  The  gross  weight  of  each  case 
is  then  determined  as  a  check  against  the  weights  marked  on 
the  cases  or  in  the  specification.  The  cases  are  then  emptied 
and  the  rubber  inspected  and  sampled.  This  is  done  in  buildings 
usually  well  lighted,  and  provided  with  fire-proof  floors  ;  the 
contents  of  each  box  are  kept  separate.  Care  is  taken  to  keep 
the  rubber  clean  and  free  from  impurities,  such  as  chips  of  wood, 
dust,  etc.  The  samples  are  selected  to  represent  the  contents 
of  each  case,  and  are  forwarded  to  the  selling  brokers,  the  cases 
being  then  coopered,  tared,  re-filled  and  weighed,  and  then  stored 
in  vaults  or  cellars  reserved  exclusively  for  this  purpose.  It  should 
be  noted  that  almost  all  grades  of  wild  rubber  except  Para  arrive 
in  bales. 

In  the  work  of  emptying,  sampling  and  re-filling,  some  whar- 
fingers prefer  a  top  light,  others  a  well-lit  floor  without  a  top  light. 
Where  top  floors  are  used,  the  temperature  and  light,  especially 
in  hot  weather,  may  lead  to  discoloration  and  excessive  loss  in 
weight.  The  rooms  are  usually  maintained  at  a  uniform  low 
temperature  and  well  ventilated  and  not  too  dry.  Dryness  maj' 
with  wet,  wild  rubbers  encourage  a  great  loss  in  weight  due  to 
evaporation  of  water,  a  point  of  some  importance  if  and  when  the 
rubber  has  to  be  stored  many  weeks  or  months. 

Sorting  at  the  Wh.\rves. 

The  rule  ii}  re-filling  (after  taring  and  sampling,  is  that 
the  rubber  is  made  up  again  in  exactly  the  same  lots  and  cases. 
When  so  instructed,  the  rubber  from  several  cases  is  repacked  into 
a  single  box  by  the  wharfinger,  who  may  not  use  his  discretion 
as  to  what  lots  may  go  together. 

If,  on  sampling  the  rubber,  it  is  found  to  be  mixed  in  quality 
and  colour,  the  attention  of  the  merchants  or  the  selling-brokers 
is  called  to  the  lack  of  uniformity.  Usueilly,  orders  are  then 
given  to  sort  the  rubber  to  quality  or  colour  as  the  case  may  be, 
but  this  is  never  done  by  the  wharfingers  in  the  absfence  of  in- 
structions to  that  effect.  It  is  obviously  necessary  that  the 
sampling  and  sorting  be  done  by  those  having  an  adequate  know- 
ledge of  the  article  so  as  to  detect  those  differences  in  quahty 
and  colour  which  represents  even  a  small  difference  in  value  ; 
experienced  men  are  engaged  on  this  work. 

It  is  worthy  of  note  that  the  regulations  of  the  insurance 
companies  do  not  allow  rubber  to  be  stored  on  the  working-floors, 
neither  do  they  allow  other  produce  to  be  worked  on  the  floors 
set  apart  for  rubber.  The  rubber  is  taken  away  to  the  special 
vaults  as  soon  as  possible  after  it  has  been  worked  and  sampled. 


CHAPTER    XXVII. 

PLANTATION     RUBBER:     ITS     CHARACTERS      AND 
COMPARATIVE  VALUE. 

Having  discussed  the  various  methods  of  preparation  and 
the  present  forms  in  which  plantation  rubber  is  now  shipped, 
I  propose  to  deal  with  the  characters  and  comparative  value  of 
plantation  rubber  from  Hevea  trees.  This  is  advisable  in  view 
of  the  diverse  opinions  expressed  by  leading  authorities  on  the 
uses  to  which  Hevea  rubber  from  plantations  can  be  applied. 
It  is  necessary  to  take  into  consideration  the  composition  of  planta 
tion  rubber,  and  to  detail  the  results  of  various  physical  tests  on 
it.  The  first  of  these  subjects  is  more  fully  dealt  with  in  the 
chapter  dealing  with  the  chemistry  and  physical  properties  of 
rubber. 

Composition    of   Hevea   Rubber. 

The  most  striking  feature  of  plantation  Hevea  rubber  is  its 
purity,  and  therefore  the  small  loss  on  washing,  compared  with 
fine  hard  Para.  Samples  of  plantation  Hevea  from  Ceylon, 
Malaya,  Africa,  and  the  West  Indies  have  been  shown  to  possess 
irom  93  to  over  95  per  cent,  of  caoutchouc  ;  the  resins  have  varied 
from  1-6  to  5'83  per  cent.  ;  and  the  proteins  from  i'2$  to  4-20 
per  cent.  The  water  in  plantation  samples  rarely  exceeds  0-6 
per  cent.,  whereas  in  fine  hard  Para  it  may  vary  from  10  to  20  per 
cent.  It  is  on  account  of  the  small  quantity  of  moisture  in 
plantation  rubber  that  the  loss  in  weight  during  transit  from  the 
East  to  London  rarely  equals  i  per  cent.,  an  allowance  of  |  per 
cent,  being  usually  sufficient.  This  high  standard  of  purity  applies 
to  all  except  scrap  grades,  and  gives  to  the  plantation  product 
the  high  reputation  it  deserves.  Notwithstanding  the  small  loss 
on  washing,  plantation  Hevea  rubber  has  not  always  secured 
a  premium  over  comparatively  wet  fine  hard  Para.  A  higher 
price  per  pound  is,  in  my  opinion,  bound  to  be  paid  for  plantation 
grades  when  they  dominate  the  market  in  point  of  quantity  as  well 
as  quality. 

Physical  Characters  of  Plantation  Hevea  Rubber. 

It  has  on  many  occasions  been  asserted  that  chemical  analyses 
alone  do  not  give  any  indication  of  differences  in  physical  properties 
and  when  used  in  reference  to  plantation  rubber  may  give  rise 
to  erroneous  conceptions.  Elsewhere  it  has  been  shown  that 
rubber  from  Hevea  trees  in  Ceylon,  varying  in  age  from  2  to  30 
years,'  showed  only  small  differences  in  chemical  composition. 


4i6  PARA     RUBBER 

though  the  physical  characteristics  of  the  various  samples  were 
widely  different.  It  is,  therefore,  necessary  to  use  additional 
tests,  of  a  physical  character,  in  determining  the  value  of  plantation 
as  against  fine  hard  Para,  though  it  is  not  impossible  that  it  will 
ultimately  be  shown  how  the  physical  properties  are  associated 
with  the  quantity  and  character  of  the  substances  indicated  in 
the  chemical  analyses. 

It  is  seldom  that  the  valuation  of  plantation  rubber  is  based 
on  chemical  analyses  alone.  On  the  other  hand  physical  characters 
are  sometimes  of  very  -little  value.  For  instance,  colour  cannot 
be  accepted  as  a  guide,  some  manufacturers  giving  preference 
to  pale  amber  and  others  to  dark,  smoked  rubber.  Only  in  the 
case  of  really  bad  samples  can  odour  be  taken  as  indicating  quaHty, 
as  the  best  samples  have  often  a  cheesy,  putrescid  smell  which  is 
more  or  less  transient. 

Early  Tests  with  Plantation  Rubber. 

Clayton  Beadle  and  Stevens  published  (Chemical  News,  July 
26th,  October  i8th,  and  November  15th,  1907)  an  account  of 
their  experiments  with  plantation  rubber.  They  vulcanized 
samples  of  plantation  and  fine  hard  Para  rubber  ;  the  products 
from  the  former  were  clear,  transparent,  yellow  to  brown  shade 
when  viewed  through  sheets  i  mm.  thick  ;  the  latter  were  much 
darker  and  less  transparent.  The  average  tensile  strength  of 
vulcanized  plantation  samples  was  3,187,  and  that  of  vulcanized 
fine  hard  Para  3,013.  The  average  elongation  at  the  moment 
of  rupture  for  the  plantation  lots  was  13,  and  for  fine  hard  Para  12-7. 
The  elongation  under  a  strain  of  1,500  grammes,  less  than  that 
necessary  to  rupture,  was  8-9  and  9-3  respectively.  Beadle  and 
Stevens  therefore  concluded  that  the  plantation  product  would 
prove  equal  to  Amazonian  Para.  They  also  subsequently  proved  in 
their  tests  on  vulcanized  plantation  rubbers  prepared  from  block 
rubber  containing  mineral  matter,  that  the  addition  of  mineral 
matter  had  the  effect  of  increasing  the  tensile  strength  while 
reducing  the  elongation. 

These  results  are  very  interesting,  but  at  the  outset  it  should 
be  pointed  out  that  probably  the  best  block  plantation  rubber 
on  the  market  was  dealt  with.  A  persual  of  the  results  gives  one 
the  impression  that  plantation  rubber  is  at  the  present  time 
quite  equal  to,  if  not  better  than,  hard  fine  Para.  Manufacturers, 
whose  experience  in  this  regard  is  surely  unique,  are  not  allot  this 
opinion.  It  is,  nevertheless,  believed  that  latex  obtained  from 
mature  plantation  Hevea  trees,  and  coagulated  in  the  proper 
manner,  is  not,  in  the  long  run,  hkely  to  prove  in  any  way  inferior 
to  wild  Hevea  latex.  The  reasons  why  there  is  lack  of ' '  resihency ' ' 
or  "nerve"  in  much  of  the  plantation  product  must  be  looked 
for  in  other  directions,  particularly  in  the  tapping  of  immature 
trees,  and  the  employment  of  methods  of  coagulation,  washing  and 
curing  which  are  not  quite  suitable. 

Tests  made  by  the  same  chemists  on  a  sample  of  Ceylon 
biscuit  did  not  give  such  good  results  as  those  made  upon  block 


PARA     RUBBER  417 

rubber,  though  they  were  even  then  not  very  different  from  the 
results  found  in  the  case  of  fine  hard  Para. 

Beadle  and  Stevens  also  published  the  results  of  their  tests 
with  hard-cure  which  had  been  washed  and  dried  by  a  manufacturer 
and  was  therefore  in  the  exact  condition  in  which  it 
would  be  used  by  the  manufacturer  himself.  The  hard-cure  Para 
supplied  by  the  manufacturer  yielded  lower  figures  for  tensile 
strength  than  the  plantation  rubber.  The  average  elongation 
at  rupture  was  greater  and  the  elongation  under  a  stress  of  1,500 
grammes  was  also  greater.  They  concluded  that  different  forms 
of  plantation  rubber  differed  materially  from  one  another,  and 
suggested  that  planters  would  require  to  consider  carefully  whether 
the  form  in  which  they  were  shipping  their  rubber  was  that  which 
gave  the  best  results  to  the  manufacturer. 

Tests  by  Schidrowitz  and  Goldsborough. 

Schidrowitz  and  Goldsborough  (Journ.  Soc.  Chem.  Ind., 
Jan.,  1909),  examined  samples  of  Ceylon  plantation  rubber  from 
trees  of  different  ages,  submitting  them  to  mechanical  tests  and 
determining  their  viscosity  in  benzene  solution,  the  latter  quality 
being,  it  is  said,  indicative  of  "nerve."  A  sample  of  fine  hard 
Para  was  also  examined  : — 

Result  of  Elonga-  Co-ef&cient  Calculated 

Age  of  Broker's  tionat        Breaking   ofresili-       viscosity 

Trees.  Hand  Test.  break.  strain.  *       ency.  *      (Benzene 

=  I). 

A.  8  yr.  trees  Weak  4-5  58  2i"6  1,000 

B.  6-13  ,,       Fairly  strong  8-o  52  24  6.65  j 

C.  30  „       Verystrong  9-75  218  57  8,843 
Fine  hard  Para     Fair,  but  old            lo-o                406             75  7.253; 

*  Grammes  per  sq.  mm.  of  cross-sectional  area. 

The  authors  made  the  following  coinments  : — ' '  The  general 
superiority  of  C  and  the  Brazilian  specimen  over  A  and  B  is 
obvious.  The  inferiority  of  B  is  not  so  marked,  however,  in 
regard  to  viscosity  as  with  respect  to  the  other  factors,  and  we 
suggest  that  it  is  possible  that  we  have  here  a  case  where  a  rubber 
is  relatively  weak  as  regards  its  mechanical  structure,  but  fairly 
satisfactory  with  respect  to  the  chemical  or  physical  structure  of  its 
mass.  It  will  be  noticed  also  that,  whereas  C  is  inferior  to  the 
Brazilian  specimen  with  regard  to  breaking  strain  and  resilience, 
its  viscosity  is  superior  to  that  of  the  latter.  We  think  that 
in  the  case  of  the  BraziUan  product  there  is  not  the  slightest  doubt 
that  a  considerable  proportion  of  its  mechanical  strength  is  due 
to  purely  mechanical  causes,  and  that  comparing  it  with  C  the 
viscosity  figures  are  probably  a  better  criterion  of  the  relative 
'nerve'  of  the  actual  rubber  substance  of  the  two  specimens  than 
the  tension  results. 

"Another  point  of  interest  is  that  the  specimen  A,  which 
is  inferior  to  B  in  every  other  respect,  shows  a  rather  higher  figure 

AA 


4i8  PARA     RUBBER 

for  breaking  strain.  We  think  the  explanation  of  this  point  is 
not  far  to  seek.  This  specimen  (A)  contained  a  good  deal  of 
insoluble  matter,  and  experience  has  led  us  to  know  that  the 
presence  of  a  certain  type  of  insoluble  matter  in  rubbers  indicates 
that  they  have  gained  somewhat  in  toughness  at  the  cost  of 
elasticity  and  resilience.  In  such  cases  the  breaking  strain  may 
be  comparatively  high,  but  the  elongation  and  resihence  are 
always  low. 

To  these  viscosity  determinations  can  now  be  added  others 
made  later  by  Schidrowitz  (Rubber,  191 1)  : — 

Viscosity. 

Plantation,  from  young  trees,  crepe   1    decidedly  1,000 

Do.                     do.               do.   [    "short"  1,400 

Do.                      do.                do.    1  1,4°° 

Do.                      do.            thin  crepe  4,400 

Do.                      do.            biscuit  8,800 

Do.         from  old  trees,     block  10,000 

Do.                      do.            thick  crepe  7,000 

Fine  hard  Para,  rather  poor  and  old  9,000 

Do.              good  specimen  12,000-14,000 


Tests   by   the  Continental  Rubber  Co. 

At  the  last  International  Rubber  Exhibition  eight  samples 
of  plantation  rubber  on  exhibit  were  tested  along  with  one  of 
fine  hard  Para  by  the  Continental  Rubber  Company  of  New  York. 
Only  two  of  the  series — unsmoked  sheet  from  Glenealy  Estate 
coagulated  with  acetic  acid,  and  some  spindle  rubber  prepared 
in  the  BraziUan  fashion  at  the  Singapore  Gardens  by  Mr.  Derry — 
were  comparable  with  fine  hard  Para  : — 


Breaking  Strain. 

Resiliency. 

Permanent  set 

Pull  after 

after  5  minutes 

Weight   Extension 

Pull 

5  minutes 

extension  &  5 

lb.            inches. 

lb. 

lb. 

minutes   rest. 

Singapore  Spindle         58                9^ 

21 

I7i 

10 

Glenealy  Sheet    .  .        64                8| 

25 

2ii 

10 

Fine  hard  Para    .  .        58                9| 

I9i 

17 

8 

The  breaking  strain  was  6  lb.  more  for  Gleneeily  sheet  than 
for  fine  hard.  Resistance  to  puU  was  greater  in  the  case  of  both 
plantation  rubbers,  5|lb.  and  i^  lb.  respectively  ;  and  sjlb.  and  ^ 
lb.  after  five  minutes.  The  figures  represent  a  permanent  set  of 
7-81  per  cent,  for  both  plantation  rubbers  and  6-25  per  cent,  for 
fine  hard  Para,  an  advantage  in  favour  of  the  latter  of  1-55  per 
cent.  Thus,  the  plantation  rubbers  were  the  tougher,  and  the 
Brazilian  the  more  resiUent.  The  Glenealy  sheet  was  from  trees 
12  years  old  or  younger,  and  the  acetic  acid  used  in  coagulation 
was  in  strength  equal  to  0-31  per  cent. 

Two  other  samples  of  smoked  sheet  from  20-year-old  trees, 
and  smoked  biscuit,  both  from  the  Singapore  Gardens,  were  also 
tested.    The  results  were  quite  dissimilar  : — 


PARA     RUBBER  419 


Breaking  Strain. 

Resiliency. 

Time  of 

Permanent  set 

Vulcan- 

Pull after 

after  5  minutes 

ization.    Break. 

Unbroken. 

Extension. 

Pull 

5  minutes. 

extension  and 

minutes.       lb. 

lb. 

inches. 

lb. 

lb. 

5  min.  rest. 

Smoked  sheet : — 

50             — 

39 

94 

13 

loi 

II 

55             47 

— 

10 

i5i 

13 

24 

45             — 

41 

loi 

13 

104 

15 

Smoked  biscuit  ;— 

50             — 

41 

10 

12J 

lOj 

14 

55             40 

— 

9i 

134 

i2i 

12 

60             75 

— 

9i 

19 

17 

8 

The  smoked  sheet  was  therefore  incapable  of  giving  good 
results  with  any  vulcanization  period,  while  the  smoked  biscuit, 
when  the  right  period  was  found,  gave  very  good  results.  No 
information  was  available  as  to  the  probable  causes  of  difference 
between  the  two  rubbers. 

Tests  made  in  New  York. 

Samples  of  plantation  rubber  from  Malaya  were  examined 
independently  by  a  number  of  chemists  in  a  New  York  laboratory, 
and  among  the  conclusions  arrived  at  were  the  following  (Straits, 
Bull.,  March,  1910)  : — 

(i)  The  potential  strength  of  the  plantation  product  was 
inferior  to  that  of  fine  hard  Para. 

(2)  The  stretch  was  satisfactory  for  all  practical  purposes. 

(3)  The  plantation  product  has  slightly  less  resin  than  fine 
hard  Para. 

(4)  Plantation  rubber  has  slightly  less  mineral  matter. 

Does  Age  of  Trees  Affect  Quality  ? 

Schidrowitz  tested  a  series  of  samples  from  trees  varjdng 
in  age  from  6  to  30  years,  and  found  unmistakable  differences 
among  them.  The  samples  from  older  trees  were  remarkably 
good,  and  for  manufacturing  purposes  were  equal,  if  not  superior, 
to  fine  hard  Para.  The  same  can  be  said  of  samples  from  2  to  30- 
year-old  trees  examined  in  Ceylon. 

A  more  recent  series  of  tests  made  in  New  York,  in  the 
laboratory  already  mentioned,  upon  rubber  from  trees  4^,  5,  9,  10, 
17,  and  27  years  old  respectively,  justified  the  conclusion  that 
rubber  from  young  trees  is  not  materially  different  from  rubber 
from  older  trees.  And  Beadle  and  Stevens  appear  to  believe  that 
the  quality  of  the  rubber  is  not  affected  by  the  age  of  the  tree 
which  jrields  the  latex. 

Plantation   Rubber  in   1907. 

The  use  to  which  manufacturers  put  plantation  rubber  is 
probably  the  best  testimony.  It  is  now  bought  at  the  rate  of  over 
15,000  tons  per  annum,  and  must  be  used  by  someone  even  though 
the  users  may  regard  it  as  inferior  in  some  respects  to  fine  hard 


420  PARA    RUBBER 

Para.  The  "India- Rubber  Journal"  (Sept.  23rd,  1907),  in  order 
to  obtain  a  definite  pronouncement  on  this  subject  at  a  time  when 
plantation  rubber  was  not  well  known,  circularised  manufacturers 
and  asked  them  if  they  would  state  for  what  purposes  they  found 
plantation  rubber  (a)  useful  and  (b)  useless.  One  firm  replied  that 
they  found  plantation  rubber  useless  in  the  manufacture  of  elastic 
thread,  and  that  they  had  no  special  purpose  for  which  plantation 
rubber  could  be  used  ;  whilst  another  firm,  which  frankly  pointed 
out  that  competition  in  business  did  not  permit  their  informing  the 
public  for  what  special  purposes  they  found  plantation  rubber 
useful,  hastened  to  state  that  for  several  purposes  they  found 
this  class  of  rubber  useless  !  Other  firms  replied  that  they  found 
plantation  rubber  useful  in  the  making  of  buffers,  soles  and  heels 
for  boots  and  shoes,  motor  tyres,  etc. 

These  replies  were  received  when  plantation  rubber  was  only 
available  in  small  quantities,  and  at  a  time  when  prominent  firms 
had  not  seen  the  advantage  of  taking  up  the  product  from  Eastern 
plantations.  We  can  now  detail  the  advances  which  have  been 
made  in  the  use  of  plantation  rubber. 

The    Manufacturer's    Point    of    View. 

So  far  in  this  chapter  attention  has  been  paid  mainly  to 
what  the  scientist  has  to  tell  us.  Now  we  may  consider  those 
points  which  appeal  to  the  manufacturer  and  may  learn  the  very 
little  that  he  chooses  to  divulge  regarding  the  behaviour  of  planta- 
tion rubber  in  the  factory. 

The  purity  of  plantation  rubber  and  its  dryness,  with  in  most 
cases  its  lightness  of  colour,  have  been  prominent  factors  in 
gaining  favour  for  it.  The  saving  in  buying  a  purer  and  drier 
rubber — a  treble  saving  when  washing  in  the  factory  is  not  added 
to  the  cost  of  manufacture  and  depreciation  of  "nerve"  during 
this  process  is  avoided — has  enabled  the  plantation  product  to 
hold  its  own  against  fine  hard  Para  when  the  tapped  trees  have 
been  comparatively  young,  when  small  and  uneven  lots  have  been 
sent  to  the  market,  and  when,  speaking  candidly,  the  planter  has 
been  serving  his  apprenticeship  in  the  production  of  rubber  from 
latex. 

Solution  appears  to  have  been  at  one  time  the  destination  of 
most  plantation  rubber,  but  the  sphere  of  usefulness  of  the  latter 
is  enlarging  as  the  quaHty  improves  and  as  the  conservatism  of  the 
manufacturer  is  dispelled.  He  has  often,  in  the  past,  had  just 
grounds  for  complaining  of  plantation  rubber,  but  that  the  justifica- 
tion for  these  complaints  is  disappearing  is  evident  from  the 
testimony  given  below  of  the  increasing  adoption  of  plantation 
rubber.  Unfortunately,  the  hands  of  the  manufacturer  are  in 
many  cases  tied  by  clauses  in  contracts  that  specify  the  use  of 
fine  hard  Para. 

The  old  complaints  regarding  the  keeping  quaUties  of  planta- 
tion rubber  are  now  becoming  rarer,  especially  in  face  of  the 
thorough  smoking  so  often  practised. 


PARA     RUBBER  421 

Upon  the  question  of  the  keeping  quahties  of  the  vulcanized 
rubber  one  public  declaration  has  been  made  which  it  would  be 
desirable  to  have  confirmed  or  otherwise  by  the  manufacturers. 
It  has  been  stated  by  Dr.  Esch  that  cold-cure  goods  made 
from  some  kinds  of  plantation  rubber  cannot  be  stored  in  the  shop 
for  a  period  of  many  months.  He  also  asserted  that  some  large 
manufacturers  in  Germany  and  Russia,  giving  a  five  years' 
guarantee  with  their  goods,  cannot  use  plantation  rubber,  though 
they  can  use  sernamby. 

Upon  the  question  of  mechanical  qualities  there  are  differences 
of  opinion.  It  is  difficult  to  learn  what  is  the  real  state  of  affairs, 
for  the  manufacturer  as  a  rule  will  not  give  us  his  confidence  ; 
only  scattered  references  are  therefore  ava:ilable.  In  this  con- 
nection one  may  direct  attention  to  the  results  already  given  in 
this  chapter  of  mechanical  tests  carried  out  in  the  laboratory. 
When  one  reads  that  plantation  rubber  vulcanizes  badly,  or 
that  the  ultimate  product  is  inferior,  one  wonders  to  what  extent 
the  methods  suitable  for  fine  hard  Para  have  been  modified  to 
suit  a  rubber  prepared  in  a  different  fashion. 

Lack    of    Uniformity    in    Plantation    Rubber. 

Upon  the  question  of  uniformity  in  qualities  and  in  behaviour 
during  vulcanization  complaints  have  frequently  been  made,  and 
certainly  they  have  often  been  justifiable. 

A  serious  disadvantage  that  may  attach  to  any  lot  or  to 
any  grade  of  rubber  from  the  manufacturer's  point  of  view  is 
uncertainty  as  to  its  behaviour  during  vulcanization.  This 
matter  requires  the  careful  attention  of  the  planter  upon  whom 
lies  the  burden  of  acquainting  himself  with  the  nature  of  the 
complaints. 

One  complaint  is  that  made  by  Mr.  A.  D.  Thornton,  of  the 
Canadian  Consolidated  Rubber  Company,  Montreal  (I.R.J., 
Oct.,  1910),  who  thus  expresses  himself  :  "If  you  will  permit,  I 
would  like  to  give  you  the  reasons  why  we,  as  large  manufacturers, 
are  forced  to  use  ' '  fine  hard ' '  in  preference  to  ' '  plantation. ' '  We 
have  used  plantation  rubber  from  the  time  it  first  came  on  the 
market,  and  we  are  still  large  users  of  it,  but  we  realize  that  while 
improvements  have  been  made,  it  is  still  far  from  what  it  should 
be.  I  refer  to  its  lack  of  uniformity.  At  the  moment  I  have  in 
mind  a  ten-ton  lot  we  are  using  at  present.  It  comes  as  No.  i 
biscuit ;  there  are  many  shades  in  colour,  the  resinous  extracts 
vary  considerably,  the  tensile  strength  (when  vulcanized)  varies 
very  considerably,  but  most  serious  of  all  is  its  variation  as  to 
vulcanizing.  With  five  samples  selected  from  one  case,  we  mixed 
the  same  amount  of  sulphur  and  Htharge,  and  vulcanized  it  in 
moulds  at  the  same  time,  and  it  shows  unreasonable  variations  in 
the  results  ;  some  were  fully  vulcanized,  some  over  and  some 
under- vulcanized. ' ' 

This  was  followed  up  by  Mr.  Thornton  with  a  further  ex- 
pression of  opinion  :     "We  have  tried  large  and  small  parcels  ; 


422  PARA     RUBBER 

the  result  is  not  satisfactory.  I  enclose  two  biscuits  taken  from 
the  same  case.  You  will  note  the  branding  is  identical,  yet 
they  differ  in  colour,  elasticity  and  time  for  vulcanization.  The 
swell  in  benzene  shows  a  still  greater  variation. 

"  If  a  dark  biscuit  is  of  a  different  nature  to  a  light  biscuit,  that 
difference  prevails  all  through  the  process  of  manufacture.  We 
don't  object  to  the  shade  as  a  shade,  but  because  it  represents 
differences  in  composition,  consequently  many  vexatious  troubles 
for  the  technical  man  in  the  factory.  Para  is  not  uniform.  I 
know  it,  but  it  is  reasonably  so,  whereas  plantation  grades  are  not. 

The  two  biscuits  were  shown  to  the  head  of  one  of  the  principal 
broker's  houses  in  London,  and  he  expressed  surprise  that  two 
samples  differing  so  widely  in  colour  should  have  been  sold  in  the 
same  case. 

An  endorsement  of  Mr.  Thornton's  statements  was  made 
(I.R.J.,  October,  1910)  by  Mr.  Brierly,  F.C.S.,  manufacturer  and 
chemis-t,  who  remarked  that,  with  very  few  exceptions,  his  firm 
was  experiencing  the  same  difficulty  and  variations,  and  that  the 
uncertainty  and  fluctuating  vulcanization  of  plantation  rubber 
appears  to  be  an  increasing  evil  both  in  the  hot  and  cold-cure,  so 
much  so,  that  his  firm  was  seriously  curtailing  its  use  of  it  and  was 
going  back  to  the  old  standard  wild  rubbers. 

Another  authority,  after  having  visited  America,  and  who 
previously  had  considerable  experience  in  testing  plantation  as 
well  as  other  rubber,  gave  it  as  his  opinion  (I.R.J.,  October,  1910) 
that  the  variation  was  more  pronounced  with  rubber  used  in  the 
United  States,  and  probably  also  in  Canada,  than  it  was  in  Great 
Britain.  He  noticed  when  in  the  States  that  plantation  lots 
which  manufacturers  there  had  were  of  a  very  mixed  description, 
biscuits  and  sheets  of  various  qualities  and  colours  being  all 
mixed  up  in  one  and  the  same  case.  Many  manufacturers  with 
whom  this  subject  has  been  discussed  agree  that  the  plantation 
product  varies  very  widely  in  regard  to  strength. 

On  the  other  hand,  Stevens,  who  pointed  out  that  fine  hard 
Para  itself  is  by  no  means  absolutely  uniform,  stated  that  two 
good  samples  of  plantation  rubber,  of  different  origin,  and  giving 
distinctly  different  results  when  vulcanized  under  uniform  con- 
ditions, were  submitted  to  a  large  manufacturer  who  reported  that 
they  did  not  differ  from  one  another  more  than  two  samples  of 
fine  hard  Para  taken  at  random. 

He  cites  also  a  case  similar  to  that  described  by  Mr.  Thornton. 
Considerable  difficulty  was  experienced  in  some  rubber  works  in 
obtaining  uniform  results,  on  vulcanization,  of  articles  cured  in 
moulds  under  apparently  uniform  conditions.  In  this  case, 
however,  the  rubber,  although  a  Hevea  rubber,  was  not  a  plantation 
product,  but  one  of  the  well-known  South  American  brands. 

He  maintains  that  both  in  colour  and  time  of  vulcanizing 
certain  grades  of  Hevea  rubber  from  Eastern  estates  with  a  wide 
reputation  exhibit  great  uniformity. 


PARA     RUBBER  423 

Causes   of  the   Variability. 

Upon  the  causes  of  this  variabiHty  one  chemist  has  suggested 
that  merchants  on  this  side  were  probably  mixing  up  odd  lots 
and  were  sending  them  across  to  America.  He  was  satisfied  that, 
on  the  whole,  the  trouble  lay  here  and  not  in  the  East.  This 
point  has  been  cleared  up  by  enquiring  into  the  methods  of  dealing 
with  rubber  at  the  wharves,  where,  on  instructions,  the  contents 
of  several  cases  may  be  repacked  into  larger  cases  for  shipment 
abroad. 

Mixing  of  Lots  on   Small  Estates. 

Now,  biscuit  and  sheet  rubber  is  frequently  prepared  by 
planters  when  dealing  with  small  crops  ;  and  it  may  be  accepted 
that  the  mixing  up  of  odd  lots  is  one  natural  result  of  the  small 
crops  that  are  being  turned  out  as  yet  from  some  young  estates. 
That  an  improvement  can  be  expected,  so  far  as  this  factor  alone  is 
concerned,  is  certain  when  large  estates  are  producing  considerable 
quantities  of  rubber.  We  may  take  it  that  time  will  lead  to 
improvements  and  that  the  range  in  variability  in  any  lots  put  on 
the  market  will  be  within  the  limits  desirable  in  manufacture.  At 
any  rate,  with  such  large  crops  as  will  be  available  in  the  future, 
manufacturers  will  be  able  to  supply  their  needs,  keeping  to 
particular  brands  with  which  they  are  familiar. 

Factors  Causing  Variability. 

Some  of  the  factors  causing  variability  will,  in  the  course  of 
nature,  or  as  a  result  of  improved  methods,  become  equalised  ; 
others  are  beyond  equalisation  or  can  be  dealt  with  only  slightly. 
On  the  one  hand,  there  are  those  inducing  inequalities  in  the 
latex  ;  and  on  the  other,  those  arising  during  preparation  of  the 
rubber.  The  first  group  includes  age  of  trees,  altitude  of  estate, 
soil,  moisture,  and  climatic  conditions,  the  quality  of  the  water 
used  for  dilution,  and  natural  variations  among  the  trees.  The 
second  includes  the  length  of  time  elapsing  between  tapping  and 
coagulation,  the  time  taken  in  coagulation,  the  strength  of  coagu- 
lant used,  the  nature  of  the  coagulant,  the  time  elapsing  between 
coagulation  and  washing,  the  amount  of  mechanical  treatment 
during  the  washing  operations,  variations  in  drying  methods 
(rate  and  temperature)  and  the  pitch  to  which  they  are  carried,  and 
such  personal  factors  as  the  attention  of  the  operators  in  the 
factory.  Though  the  first  group  is  beyond  our  control,  the  age 
factor — probably  the  most  important  of  all — will  remedy  itself 
in  course  of  time.  The  second  group  is  to-day  under  continuous 
observation  and  improved  methods  are  being  daily  effected, 
especially  in  the  use  of  acids  and  thorough  washing  without  undue 
tearing  and  stretching. 

Direct  Use  of  Plantation  Rubber. 

The  question  of  the  direct  treatment  of  plantation  rubber  for 
mastication  and  mixing  is  one  of  considerable  importance.     If  the 


424  PARA     RUBBER 

latex  is  properly  coagulated,  and  the  resultant  mass  thoroughly 
washed  and  dried  on  the  plantations  before  exporting,  it  would 
appear  superfluous  for  the  manufacturers  in  this  country  to  go 
through  the  whole  process  a  second  time,  especially  when  the 
rubber  arrives  in  the  excellent  condition  in  which  it  is  now  being 
received  from  well-equipped  estates.  This  would  save  the  manu- 
facturer the  trouble  of  softening  in  warm  water,  followed  by  the 
washing  and  drying  operations,  the  latter  being  a  particularly 
slow  process,  especially  if  the  rubber  has  to  be  stored  for  the 
purpose  of  allowing  it  to  regain  the  pecuhar  physical  condition  in 
which  it  yields  the  best  results  on  vulcanization. 

The  above  remarks  have  been  borne  out  by  actual  experience 
in  the  factory,  and  plantation  rubber  has  in  some  cases  been 
directly  used.  For  reasons  before  explained,  this  does  not  apply 
to  biscuit  and  sheet,  but  only  to  thoroughly  washed  rubbers. 

Behaviour  During  Mastication. 

It  was  asserted  by  Esch  at  the  1911  Exhibition  Conference 
that  most  of  the  plantation  rubber  on  the  market  was  unable  to 
stand  much  mastication.  But  it  was  at  once  pointed  out  that  it  is 
not  an  unusual  thing  when  two  samples  differ  in  their  behaviour 
on  the  mill,  one  breaking  down  more  readily  and  undergoing 
the  milling  less  perfectly,  to  have  the  two  after  vulcanization  of 
equal  quality. 

At  the  same  conference,  Jaques,  who  has  had  several  years 
experience  in  rubber-mills,  took  up  a  somewhat  different  position 
to  Esch.  He  remarked  that  a  few  plantation  kinds  do  not  soften 
readily  on  the  rolls,  and  that  it  is  impossible  often  to  get  good 
calendered  sheet.  But  he  admitted  that  there  are  other  kinds  that 
are  more  amenable  on  the  mixing  rolls  than  hard-cure  Para,  which 
behave  as  well  in  calendering,  vulcanize  more  readily,  and  are 
stronger.  When  vulcanized  under  the  proper  conditions,  the 
finished  product,  like  fine  hard,  improves  with  keeping.  He  con- 
sidered that  the  tensile  properties  of  vulcanized  first-quality 
plantation  rubber  are  sometimes  equal  to  those  of  fine  hard 
Para.  On  the  other  hand,  there  are  some  smoked  and  pale  kinds 
that  are  of  better  quality  than  the  average  hard-cure. 

Plantation  Rubber  for  Solutions. 

Plantation  rubber  is  said  to  be  preferred  by  many  manufac- 
turers for  ' '  solutions ' '  on  account  of  their  being  able  to  use  it 
directly  without  purification.  Coal-tar  and  mineral  naphthas 
are  used  as  the  solvents.  Fine  hard  Para,  if  masticated,  appears 
to  be  dissolved  quicker  by  naphtha.  Biscuits  from  plantations  are 
sometimes  more  difficult  to  dissolve  than  washed  masticated 
crepe.  Plantation  rubbers,  if  pure,  are  gaining  in  favour  among 
manufacturers  for  this  purpose. 


PARA     RUBBER  425 

Elastic   Thread   the   Highest   Test. 

It  is  generally  acknowledged  that  rubber  in  the  form  of 
elastic  thread  is  subjected  to  the  severest  of  tests.  Elastic  thread 
represents  one  of  the  highest  classes  of  rubber  goods.  Upon  this 
point  (T.R.T.,  Nov.,  1908),  it  has  been  reported  that  an  EngUsh 
manufacturer,  who  had  made  a  quantity  of  elastic  thread  from 
Lanadron  block,  found  that  the  results  were  equal  to  those  obtained 
from  average  fine  hard  Para.  He  further  stated  that  he  saw  no 
reason  why  plantation  rubber  in  general,  when  prepared  under 
the  best  conditions,  should  not  be  capable  of  giving  results  equal 
to  those  obtained  with  fine  hard  Para.  Another  sample  of  this 
thread  was  submitted  to  a  firm  of  elastic  webbing  manufacturers, 
who  ultimately  described  it  as  "  very  satisfactory. ' ' 

This  view  is  not  held  by  another  manufacturer,  Mr.  P.  M. 
Matthew  (I.R.J.,  Feb.,  1909),  of  the  Victoria  Indiarubber  Mills, 
Edinburgh,  who  said  that  he  was  aware  that  it  was  the  view  of  some 
experts  that  plantation  rubber  could  be  used  for  any  purpose,  and 
that  splendid  thread  rubber  could  be  made  from  it,  but  this  was 
not  his  opinion.  Ht  further  asserted  that  there  is  no  doubt  that  if 
properly  treated,  plantation  rubber  can  be  successfully  employed 
for  most  purposes  for  which  wild  Para  is  now  used  and  possibly  in 
time  to  come  it  may  be  used  in  the  manufacture  of  thread,  which 
is  probably  the  highest  test  of  quality  to  which  it  can  be  subjected. 
He  had  made  many  experiments  with  the  object  of  determining 
the  relative  merits  of  fine  Para  and  cultivated  rubber,  with  the 
result  that  the  latter,  though  available  for  most  purposes,  could  not 
be  substituted  for  the  former  in  such  goods  as  elastic  thread. 

The  moral  of  these  two  statements  appears  to  be  that  all 
plantation  rubber  is  not  as  excellent  as  Lanadron  block. 

Though  Mr.  Matthew  could  not  admit  the  availability  of 
plantation  rubber  for  elastic  thread,  at  a  later  date  (I.R.J., 
Oct.,  1910),  he  claimed  for  it  a  utihty  for  most  purposes.  He 
pointed  out  that  there  are  some  purposes  for  which  it  is  still 
found  necessary  to  employ  fine  Para  in  preference  to  plantation 
rubber,  but  not  for  reasons  connected  with  its  durability.  The 
difference  in  the  method  of  coagulating  and  curing  the  two  rubbers 
necessitates  different  treatment  in  the  various  processes  of  manu- 
facture, but  when  this  is  thoroughly  understood  Mr.  Matthew 
believed  that  for  nine-tenths  of  the  purposes  for  which  wild  Para 
is  now  used,  the  best  plantation  rubber  could  be  employed  with 
equal  advantage.  He  had  subjected  plantation  rubber  to  severe 
tests,  including  those  for  durability  prescribed  by  the  Admiralty 
and  the  War  Of&ce,  and  had  obtained  satisfactory  results. 

Plantation  Rubber  for  Wire  Covering. 

Though  there  is  some  obscurity  in  the  following  extract 
from  a  letter  by  Mr.  Henry  A.  Morss,  Boston  (I.R.J.,  Nov.,  1910), 
it  is  clear  that  some  plantation  rubber  as  at  present  prepared 
has  at  least  one  limitation.  Morss  bought  a  small  amount  of 
crepe  rubber  in  Singapore,  and  experimented  with  it,  comparing 


4^6  PARA     RUBBER 

it  with  South  American  Para.  So  far  as  his  own  business  is 
concerned,  which  is  the  making  of  rubber-covered  wires  and  cables, 
the  rubber  that  he  bought  was  not  satisfactory.  However, 
he  had  some  further  experience  with  plantation  rubber,  having 
bought  several  small  lots,  mostly  from  Ceylon.  His  experience 
was  that,  while  plantation  rubber  is  clean,  and  on  the  whole  has 
good  mechanical  quahties,  only  smoked  rubber  is  suitable  for 
his  use.  He  had  been  unable  to  make  a  compound  with  acid- 
cured  rubber  which  would  withstand  the  searching  electrical 
tests  necessarily  apphed.  On  the  other  hand,  he  had  been  able 
to  do  fairly  well  with  smoked  Ceylon,  although,  owing  to  varying 
quahty,  it  could  not  be  depended  upon  for  the  highest  class  of  work. 
Though  Mr.  Morss  is  obviously  under  a  misconception  as  to 
the  method  by  which  smoked  plantation  rubber  is  prepared,  the 
fact  remains  that,  in  his  opinion,  it  is  not  entirely  suitable.  It 
will  be  noted  that  it  does  fairly  well,  presumably  in  withstanding 
the  electrical  tests,  but  beyond  this  is  the  objection  of  varjdng 
quality. 

Plantation   Rubber   and   Cut   Sheet. 

At  the  last  International  Exhibition  Conference,  1911,  Esch 
asserted  that  the  results  of  experiments  carried  out  by  him  for 
a  large  German  rubber  factory  showed  that  good  cut  sheet  could 
be  manufactured  from  second-grade  Caucho  ball,  but  they  had 
not  been  able  to  make  it 'from  the  best  plantation  light  crepe. 
Yet  he  admitted  that  some  kinds  of  plantation  rubber  could  be 
used ;  apparently  some  manufacturers  fear  that  they  wUI 
not  be  able  at  any  time  to  obtain  lots  sufficiently  large  for  their 
purpose,  lots  of  a  size  that  they  may  obtain  again  as  their  require- 
ments demand.  Terry  added  to  this  by  saying  that  it  was  a 
well-known  fact  that  plantation  rubber  did  not  produce  good  cut 
sheet.  He  also  remarked  that  card-cloth  manufacturers  used 
fine  hard  Para  only,  and  not  plantation  rubber. 

Clayton  Beadle  and  Stevens  (Rubber,  p.  105)  state  that  not 
only  are  lower  grade  rubbers  being  used  in  admixture  with  fine 
hard  Para  for  second-grade  sheet,  but  special  pale  cut  sheet  is 
now  being  made  from  plantation  rubber  stronger  than  that  of 
first  quality  made  exclusively  from  fine  hard  Para.  They  report 
that  plantation  rubber,  despite  its  purity,  is  for  cut  sheet  generally 
washed  by  the  manufacturer  before  being  used  for  this  purpose. 

Plantation  Rubber  for  Tyres. 

The  reputed  inferiority  of  recently  manufactured  articles, 
such  as  tyres,  has  been  lately  emphasized,  the  imputation  being 
that  plantation  grades  have  been  used,  and  that  these  are  inferior 
to  fine  hard  Para.  It  has  also  been  stated  in  my  hearing  that  a 
well-known  Continental  manufacturer  pubHcly  announced  that 
plantation  rubber  was  not  used  in  the  manufacture  of  tyres  made 
by  his  firm.  We  have  further  been  assured  by  other  manufacturers 
that  they  have  not  yet  used  plantation  rubber  for  tyres.     The 


PARA     RUBBER  427 

gentlemen  making  these  statements  are  connected  with  some 
of.  the  very  best  firms  in  Europe. 

There  is,  it  will  be  noted,  not  a  single  definite  statement 
that  plantation  rubber  cannot  be  used  for  tyres,  and  I  do  not  know 
of  any  evidence  of  its  unsuitability  as  determined  in  practice, 
nor  of  any  reason  why  it  should  not  be  used  when  properly 
prepared,  excepting,  of  course,  rubber  from  young  trees.  Had 
there  been  any  serious  objection  to  its  use,  one  would  have  heard 
much  more  definitely  of  this.  Tyre  rubber  passes  through  most 
severe  tests  in  practice  which  demand,  in  a  high  degree,  all  the 
essential  qualities  of  a  rubber. 

At  the  last  International  Rubber  Exhibition,  one  firm  manu- 
facturing tyres  proclaimed  its  adhesion  to  the  use  of  plantation 
rubber  for  this  purpose.  At  the  conference,  Esch  stated  that  in 
Germany  manufacturers  are  unable  to  extensively  use  plantation 
rubber  for  tyres,  the  reason  being  that  very  large  mixing  machines 
are  used,  the  quantity  of  rubber  necessary  to  keep  them  going 
not  being  available  of  sufficient  uniformity.  Yet  he  also  stated 
that  aU  large  manufacturers  who  use  hard-cure  rubber  could  not 
use  plantation  rubber  for  goods,  such  as  tyres,  that  have  to  undergo 
attrition. 


CHAPTER  XXVIII. 


CHEMICAL    AND    PHYSICAL    PROPERTIES   AND 
TESTING   OF    RUBBER. 

The  preparation  of  rubber  from  latices  having  been  fuUy 
described,  it  is,  before  considering  the  uses  to  which  rubber 
is  put,  advisable  to  discuss  the  chemical  and  physical  pro- 
perties of  the  raw  product.  The  characteristics  of  Hevea  rubber 
obtained  from  different  parts  of  the  tropical  world  are  of  primary 
importance,  and  are  here  considered  first.  The  composition  of 
other  rubbers  of  various  kinds  from  the  East,  Africa  and  Brazil 
is  then  dealt  with. 

Composition  of  Rubber  from  Malaya. 


Variously  prepared  forms  of  rubber 
States  were  analysed  at  the  Imperial 
3),  with  the  following  results  : — 


from  the  Federated  Malay 
Institute    (Bulletin  V.,  No 


Moisture. 

0/ 

Ash. 

/o 
o-i6 

Resin. 

0/ 

Proteins. 

0/ 

Caoutchouc 

0/ 

Crepe,  pale  yellow 

/o 

0-22 

/o 

275 

7o 
2-27 

/O 

94-60 

Large,  thin  biscuits 

,  pale   . .         0-36 

0-29 

2-23 

2-31 

94-81 

Thin  sheets,  pale,  opaque  . .         0-54 

0-48 

I '64 

2-66 

94-68 

Crepe,  almost  white 

0-26 

o'34 

3-58 

3-i8 

92-64 

Ditto,  dark  brown 

060 

o"56 

2-89 

2-50 

•53 -45 

Sheet,  very  pale 

0-38 

0-36 

178 

3-08 

94-40 

Crepe,  almost  whitt 

0-32 

o-i8 

2-83 

2-99 

93-68 

Large  biscuit,  pale 

042 

0-46 

1-38 

2-13 

95-61 

Crepe,  hght  brown 

0-28 

0-23 

2-82 

2-IO 

94-48 

Sheet,  dark 

044 

0-35 

2-45 

1-94 

94-82 

Ditto,  pale   .  . 

0-38 

0-28 

1-83 

2-36 

95'I5 

Ditto,  rather  dark 

0-36 

034 

2-07 

2-36 

94-87 

Ditto,  pale  . . 

052 

0-43 

2-57 

3-06 

93-42 

Crepe,  yellow 

0-42 

0-14 

3-OI 

2-90 

93-53 

Thin  sheet,  pale 

0-22 

0-2I 

1-87 

I '35 

96-35 

Sheet,  pale  . . 

0-38 

0-27 

175 

213 

95-47 

Minimum  valu 

es             .  .             0'22 

014 

1-38 

I '35 

92  64 

Maximum  vali 

les        . .         o-6o 

050 

3-58 

3-i8 

9635 

Analyses  of  Ceylon  and  S.  Indian  Rubber. 

The  following  are  some  of  the  analyses  of  Hevea  rubbers  as 
published  in  the  Official  Handbook  of  the  Ceylon  Exhibition  of 
1906  ;  the  first  four  rubbers  were  gold  medal  samples  : — • 

Moisture.   Resin.      Ash.     Proteins.  Caoutchouc 


0/ 

/o 

% 

/o 

% 

0/ 
/o 

Duckwari  biscuits  .  . 

0-68 

2-32 

036 

3-00 

93-64 

Arapolakande  smoked  bis- 

cuits    . . 

0-28 

1-84 

0-20 

2-12 

95-56 

Syston  sheet 

0-30 

2-74 

0-20 

2-25 

94-51 

Lanadron  block 

0-36 

2-44 

0-20 

3-31 

93-69 

Hawthorn  Estate,  S.  India, 

biscuits 

0-60 

3  02 

0-40 

2-82 

93-16 

Typical  weak  sheets 

1-04 

3-34 

0-36 

2-82 

92  44 

Typical  weak  biscuits 

0-68 

2-14 

0-24 

3-00 

93-94 

PARA     RUBBER 


429 


Taking  the  whole  of  the  prize  samples,  the  range  of  variation 
was  as  follows  :  moisture,  o-i8  to  i-i8  per  cent.  ;  resin,  i-i8  to 
4-84  per  cent.;  ash,  0-20  to  0-84  per  cent.  ;  proteins,  i'25  to 
7-31  per  cent.;  caoutchouc,  91-89  to  95"93  per  cent. 

As  far  as  the  chemical  composition  of  the  rubber  goes,  there 
seems  nothing  to  account  for  the  differences  in  the  strength  of 
various  plantation  and  other  rubbers.  The  splendid  Duckwari 
biscuits  and  "typical  weak  biscuits"  show  practically  no  differ- 
ence in  chemical  composition,  the  percentage  of  moisture  and 
proteins  are  identical,  and  the  weak  rubber  contains  less  ash  and 
less  resin  but  more  caoutchouc  than  the  gold  medal  sample. 

Typical  weak  shee  contains,  according  to  the  analyses, 
more  moisture  than  any  of  the  samples. 

The  best  plantation  samples  at  the  Ceylon  Rubber  Exhibition 
contained  practically  no  moisture  in  the  majority  of  cases,  there 
being  less  than  i  per  cent,  present,  while  a  typical  sample  of  weak 
Para  sheet  contained  1-04  per  cent,  of  moisture. 

Messrs.  Schidrowitz  and  Kaye,  in  the  Journal  of  the  Chemical 
Society,  have  dealt  with  the  composition  of  Ceylon  biscuits  of 
various  thicknesses.  Other  analyses  by  the  same  chemists  show 
that  rubber  prepared  from  Ceylon  latex  possessed  from  about 
86  to  over  90  per  cent,  of  caoutchouc,  when  the  moisture  ranged 
from  5  to  9  per  cent. 


Chemical  Composition  of  Hevea  Plantation  Rubber. 

The  following  analyses,  in  some  cases  averages  of  analyses, 
are  given  by  various  authorities,  including  the  Imperial  Institute, 
Bamber,  etc.  : — 


Ceylon 

0/ 

Bukit 
Rajah. 

0/ 

Penang. 

Straits 
Rubber, 
old. 

% 

Gold 

Coast 

(average) 

°L 

South 

Nigeria 
(average) 

Caoutchouc 
Resins  .  . 
Proteins 

,0 
3-00 

1-25 

/o 

9537 

3-02 

1-24 

/o 

95-00 
4-08 

? 

/o 

93-22 

1-76 

4-20 

/o 

9574 

3-58 

? 

93 '0 
2-6 
20 

Ash       .. 
Moisture 

0-25 

0-37 

0-05 
0-I5 

0-32 
0-50 

0-22 

0-57 

0-3 
2-1 

Nilgiris        Mergui      Martinique 
(average),  (average),    (average). 
0/                  0/                  0/ 

Trinidad 
(average) . 

Dominica 

°/ 

Caoutchouc .  . 

Resins 

Proteins 

Ash 

Moisture 

/o 

917 

33 
3 '3 
i-i 
06 

/o 
95-2 
1-6 
2-4 
0-3 
0-5 

/o 
90-5 
4-24 
3-38 
0-30 
1-58 

/o 

gi-i 

3-4 
2-1 

0-5 
2-9 

/o 

930 

4.2 

2-1 
0-3 
0-4 

The  high  percentage  of  caoutchouc  in  Hevea  rubber,  grown  in 
different  countries,  is  so  far  very  satisfactory.  It  has  been  shown 
that  whereas  the  rubber  from  Hevea  under  cultivation  may  contain 
over  95  per  cent,  of  caoutchouc  and  less  than  4  per  cent,  of  re- 
sinous matter,  the  native  African  rubber  (Funtumia  elastica) 
contains  less  than  90  per  cent,  of  caoutchouc  and  over  8  per  cent, 
of   resinous   compounds.     From   the   foregoing   analysis  it    may 


430 


PARA     RUBBER 


safely  be  asserted  that  Hevea  hrasiliensis  bids  fair  to  beat  many 
rubber  trees  indigenous  to  tropical  areas.  Resins  in  large  quanti- 
ties, proteins,  and  ash  constituents  are  not  required,  and  in  many 
articles  of  commerce  are  injurious. 

Composition  of  Other  Rubbers. 

It  will  be  seen  from  the  analyses  below  how  much  richer 
Hevea  rubber  is  in  caoutchouc  than  are  the  rubbers  from  other 
plants.  Compared  with  that  from  Ceara  and  Castilloa  trees, 
Hevea  rubber  is  much  less  resinous.  Such  differences  are 
reflected  in  the  physical  qualities  of  these  rubbers.  Taking  the 
analyses  as  a  whole,  and  noting  the  inferiority  in  quality  of  some 
of  the  kinds  as  indicated  by  their  market  values,  one  is  compelled 
to  acknowledge  that  chemical  analyses  have  some  real  value  in  such 
instances. 


Ceylon  Hevea,  Ceara  and  Castilloa  Rubbers. 

The  chemical  characteristics  of  rubber  from  Hevea,  Manihot 
(Ceara),  and  Castilloa  trees  grown  in  Ceylon  are  exemplified  in 
the  following  analyses  (Comm.  Agr.  Expts.,  Nov.,  1905)  : — 


Hevea. 

Ceara. 

Castillo 

0/ 
/o 

% 

0/ 

/o 

Caoutchouc 

94-60 

76-25 

86-19 

Resin 

2-66 

10-04 

12-42 

Proteins 

175 

8-05 

0-87 

Ash 

0-14 

2-46 

0-20 

Moisture 

0-85 

3-20 

0-32 

African  and  Eastern  Wild  Rubbers. 

The  essential  differences  in  chemical  composition  between 
various  wild  rubbers  obtained  from  Africa  and  the  East  are  mani- 
fest from  the  numerous  analyses  pubUshed  in  the  Bulletins  of  the 
Imperial  Institute,  London. 

The  following  are  a  few  typical  examples  : — 

Landolphia       Landolphia      Landolphia 


Kirkii. 

0/ 

Petersiana.     Watsoniana. 

0/                                   n' 

Caoutchouc 

/o 

8o-i 

70 
677 

/o 

67-2 

Resin 

6-9 

ii'i 

II-9 

Dirt  and  insoluble  matter 

5-3 

3'4 

8-0 

Ash  included  in  dirt 

0-31 

1-2 

13 

Moisture  . . 

77 

177 

12-9 

Species 

Ficus 

Urceola 

Rhynchodia 

of  Ficus. 

elastica 

esculenta 

.    WalUchii. 

0/ 
/o 

% 

% 

% 

Caoutchouc 

19-6 

84-3 

8o-5 

86-5 

Resin 

49  9 

ii-S 

9-8 

6-5' 

Dirt  and  insoluble  matter 

2-1 

3"! 

57 

4-2 

Ash  included  in  dirt 

079 

0-8 

i-i6 

0-48 

Moisture 

28-4 

0-8 

4-0 

V8 

PARA     RUBBER  431 

Relationship  Between  Chemical  and  Physical 
Characters. 

It  has  been  previously  pointed  out  that  the  physical  characters 
of  various  oils,  gums  and  resins  can  generally  be  associated  with 
differences  in  chemical  composition.  A  slight  change  in  the 
proportion  of  certain  chemical  ingredients,  or  reduction  or  oxida- 
tion of  components  in  a  mixture,  often  appreciably  affects  the 
physical  properties  of  the  products  under  observation.  The  same 
may,  to  a  hmited  extent,  be  said  of  various  rubbers  which  regularly 
appear  on  the  market.  An  increase  in  the  percentage  of  resinous 
constituents  may  change  the  rubber  to  a  brittle  or  sticky  mass, 
and  it  is  already  possible  to  group  some  rubbers  according  to 
their  chemical  composition  and  associated  physical  properties. 
Chemical  analyses,  even  as  submitted  to-day  in  their  undoubtedly 
empirical  and  undesirable  form,  allow  us  to  distinguish  sometimes 
the  botanical  sources  of  certain  latices  and  rubbers,  though 
the  plants  yielding  them  may  not  at  the  time  be  available  for 
botanical  verification.  But  no  one  can  deny  that  the  analyses  of 
rubber  as  at  present  submitted  often  give  no  indication  of  the 
physical  differences  which  exist  between  samples  of  rubber 
obtained  from  Hevea  trees  of  different  ages.  This  does  not 
necessarily  disprove  that  a  correlation  exists  between  the  chemical 
composition  and  physical  properties  of  the  rubber,  but  suggests 
that  the  analyses  do  not  distinguish  the  differences  between 
the  components  of  the  groups  enumerated.  It  is  not  sufficient 
to  merely  state  the  percentage  of  resinous,  protein,  and  caoutchouc 
contents  in  samples  of  rubber.  This  grouping  of  most  of  the  con- 
stituents and  the  calculation  of  caoutchouc  by  difference  does  not 
give  us  any  idea  of  the  differences  which  we  are  led  to  beheve 
exist  between  the  proteins  involved  in  the  phases  of  coagulation 
and  those  which  appear  in  solution  after  the  complete  separation 
of  the  caoutchouc  ;  neither  does  it  give  us  a  clear  conception  of 
the  differences  between  the  components  in  each  of  the  other 
groups  or  between  the  individual  resins  and  caoutchouc  globules  in 
trees  of  different  ages,  and  in  the  latex  from  different  species. 

Dunstan,  in  his  address  before  the  British  Association  in 
1906,  pointed  out  that  the  chemical  analysis  of  raw  rubber  as  at 
present  conducted  is  not  always  to  be  taken  by  itself  as  a  trust- 
worthy criterion  of  quality,  and  more  refined  processes  of  analysis 
are  now  needed.  In  a  recent  Bulletin  of  the  Imperial  Institute  he 
again  emphasises  this  point.  He  states  that,  "at  present  the 
caoutchouc  is  usually  determined  by  difference  from  the  results 
of  the  direct  determination  of  the  other  constituents.  All  the 
errors  of  the  analysis  a-e  therefore  concentrated  in  the  stated 
percentage  of  caoutchouc,  whilst,  in  the  absence  of  an  accurate 
direct  determination  of  the  caoutchouc,  the  homogeneity  of  this 
constituent  in  different  samples  of  crude  rubber  and  in  rubbers 
of  different  origin  has  to  be  assumed.  The  physical  characters 
of  rubber  are  still  more  roughly  determined  by  the  manual  tests 
of  brokers,  and  precise  methods  of  determining  strength  and 
resiliency  are  much  needed. ' ' 


432  PARA     RUBBER 

It  is,  however,  the  opinion  of  many  that  though  the  chemical 
composition  of  rubber  may  exhibit  considerable  variation,  the 
physical  properties  of  raw  rubber  can  often  be  correlated  with 
them.  The  elastic  caoutchouc  in  the  various  rubbers  is  of  a 
very  similar  chemical  structure,  and  the  same  may  be  said  of  some 
of  the  ingredients  of  raw  rubber  which  have  already  been  isolated. 

The  Properties  of  Rubber  Constituents. 

In  the  analyses  here  given  it  will  have  been  noticed  that  the 
constituents  previously  recorded  in  the  chapter  on  the  composition 
of  latex  are  still  present  in  the  raw  product.  In  most  cases, 
perhaps  in  all  excepting  the  caoutchouc  and  proteins,  the  latex 
constituents  are  very  similar  in  their  properties  to  those  in  the 
dry  rubber.  Irrespective  of  these  relationships  between  the  same 
groups  of  constituents  in  latex  and  rubber,  there  are  many  points 
of  interest,  chemical  and  physical,  to  discuss  in  connection  with 
each  component  of  the  finished  raw  product. 

The   Caoutchouc   Hydrocarbon. 

The  caoutchouc  globules  present  in  the  latex  persist  (according 
to  Schidrowitz,  who  examined  Hevea  and  Funtumia  rubbers 
under  the  microscope  in  order  to  determine  this  point)  in  the 
crude  rubber  Specially  prepared  sections  exhibited  globules 
in  appearance  and  size  similar  to  those  occurring  in  the  latex. 
They  were  also  seen  in  the  solutions  of  the  rubber  prepared  with 
benzene,  and  in  the  films  left  after  evaporation  of  the  latter. 
Fickendey  cannot  confirm  this,  and  believes  that  the  globules  lose 
their  identity  during  coagulation. 

The  chemical  nature  of  the  caoutchouc  hydrocarbon  is  stiU 
largely  a  matter  of  discussion,  though  upon  the  physical  side 
matters  are  a  little  clearer.  It  is  a  colloid,  that  is,  a  substance  of 
very  high  molecular  weight  with  accompanying  physical  character- 
istics. One  of  the  tests  of  such  a  body  is  that,  suspended  as 
particles  in  the  form  of  an  emulsion,  or  as  a  solution,  it  will  not 
pass  through  an  animal  membrane,  as  does  a  crystalline  body  in 
solution. 

Resins    in    Rubber. 

In  addition  to  the  resins  already  present  in  the  latex,  the 
quantity  of  resins  in  prepared  rubber  gradually  increases  owing 
to  oxidation  of  the  caoutchouc  hydrocarbon,  a  change  that  leads 
to  gradual  loss  by  the  rubber  of  its  essential  physical  quahties. 
Fine  hard  Para  is  said  to  possess  from  i  to  4  per  cent  of  resins 
when  obtained  from  mature  trees. 

Resins  and   Age   of  Plants. 

The  percentage  of  resin  in  rubber  appears  to  vary  according 
to  the  age  of  the  trees,  or  the  part  of  the  plant,  whence  it  is  derived. 
Bamber  analysed  samples  of  rubber  from  Hevea  trees  in  Ceylon 
which  varied  in  age  from  2  to  30  years.  The  following  are  the 
details  : — 


PARA     RUBBER  433 

Six  Seven 

Two  years.  Four  years.  years.        years. 

Resin    ..  '. .       3-25  &  3-60%         3-28  &  272%  275%       2-10% 

Eight  years.       Ten-twelve  years.  Thirty  years. 

Resin    ..  ..  2-66%  2-26%  2-32% 

According  to  Hooper,  a  more  marked  difference  is  observable 
in  the  resin  from  Ficus  elastica  (Rambong)  rubber.  He  states 
that  the  percentage  of  resin  varies  from  about  20  to  30  per  cent,  in 
rubber  from  young  trees  to  less  than  10  per  cent,  in  that  from  older 
trees. 

Weber  has  similarly  shown  that  in  the  case  of  Castilloa 
rubber  the  percentage  of  resin  decreases  with  increase  in  age. 
Rubber  from  eight-year-old  trees  gave  7-21  per  cent,  of  resin,  and 
that  from  three-year-old  trees  35-02  per  cent. 

It  will  be  noticed  that  Hevea  rubber  does  not  show  the 
same  great  reduction  in  percentage  of  resin  with  an  increase  in 
age.  In  this  respect  Hevea  seems  to  occupy  a  somewhat  isolated 
position. 

Resins  and  Part  of  Plants. 

There  is  also  a  relationship  between  the  percentage  of  resin 
n  rubber  and  the  age  of  the  section  of  the  tree  whence  the  rubber 
is  derived. 

In  the  case  of  Castilloa  elastica,  Weber  proved  that  not  only 
does  the  percentage  of  resin  decrease  with  the  age,  but  that  it 
increases  as  one  passes  to  younger  parts  of  the  same  tree.  His 
figures  were  as  follows  : — 

% 
Trunk       . .  . .  . .  . .         2"6i 

Largest  branches  ..         377 

Medium       4-88 

Young         5-86 

Leaves     . .  . .  . .         7*50 

This  increase  in  percentage  of  resin  as  one  passes  from  the 
old  to  the  younger  parts  of  the  plant  is  very  pronounced  in  Castilloa, 
and  probably  occurs,  though  to  a  less  extent,  in  many  other  species. 

Resins  in  Various  Rubbers. 

The  following  percentages  of  resins  in  various  rubbers  are 

given  by  Weber  : — 

% 
Paxa  {Hevea  brasiliensis)    ..  ..  i"3 


Ceara  {Manihot  Glaziovii) 
Colombie  (Castilloa  elastica) 
Madagascar  (Landolphia  ?) 
Assam  (Ficus  elastica) 
Mangabeira  (Hancornia  sp.) 
African  beills 


2T 

3-8 

8-2 

II-3 

13-1 

27-8 


The  resins  are  a  highly  complex  class  of  bodies  consisting, 
as  a  rule,  of  a  mixture  of  various  constituents ;  different  resins 
behave  in  different  ways  and  their  conditions  as  well  as  quantity 


BB 


434  PARA     RUBBER 

.  are  of  importance.  It  is  possible  that  some  resins  are  not  only 
not  disadvantageous,  but  possibly  of  advantage  up  to  a  certain 
point.     This  certainly  applies  to  the  harder  resins. 

Removal  of  Resins  from  Rubber. 

Though  the  various  "Plantation"  and  "Wild"  rubbers 
which  arrive  in  Europe  contain  resin  in  quantities  varying  from 
I  to  about  40  per  cent.,  they  appear  to  be  all  subjected  to  a  some- 
what similar  process  in  the  attempt  to  extract  this  ingredient. 
According  to  Weber,  the  resins  can  be  removed  by  extracting 
with  acetone  in  a  Soxhlet  extractor,  the  highly  porous  washed 
sheets  of  rubber  lending  themselves  best  to  this  purification 
process.  The  complete  extraction  of  these  resins  from  rubber 
requires  many  days.  The  presence  of  the  resinous  impurities 
influences  the  behaviour  of  the  rubber  in  practical  working  and  also 
the  stability  of  the  finished  article.  Owing  to  the  supposed 
detrimental  effect  of  the  resins  after  vulcanization,  no  efforts 
are  spared  to  reduce  them  to  the  desired  quantity  in  inferior 
brands  of  rubber.  The  extraction  of  some  of  the  resinous  bodies 
from  the  latex  of  certain  plants  is  a  subject  which,  though  crowded 
with  difficulties,  might  profitably  engage  the  time  of  the  producer 
in  the  tropics. 

The  Effects  of  Resins  upon  ^'uLCANIZATION  of  Rubber. 
The  presence  of  resins  in  plantation  rubber  and  in  wild  Para 
and  other  rubbers  has  an  important  bearing  upon  the  reactions 
that  take  place  during  vulcanization.  According  to  the  India- 
Rubber  Journal  of  August  13th,  1906,  Dr.  R.  Ditmar  made  a  careful 
comparison  of  several  brands  of  rubber,  and  communicated  the 
results  of  his  observations  to  the  ' '  Gummi  -  Zeitung. ' '  The 
amount  of  resin  contained  in  each  sample  having  been  first  deter- 
mined, 10  gram  lots  of  the  various  brands  were  vulcanized  with 
10  per  cent,  of  sulphur  at  145  deg.  C,  under  a  pressure  of  3-4 
atmospheres,  for  one  hour,  and  then  tested  for  elasticity  and 
tensile  strength.  It  was  found  that  fine  hard  Para,  containing 
1-44  per  cent,  of  resin,  was  completely  vulcanized  and  was  very 
elastic.  It  was  only  surpassed  in  the  latter  respect  by  ilozam- 
bique  balls  and  spindles,  Massai  balls,  and  Ceylon  plantation 
rubber.  The  behaviour  of  the  Mozambique  ball  was  remarkable, 
for,  although  it  was  considerably  richer  in  resins  and  was  not 
fully  vulcanized,  it  showed  a  greater  elasticity  and  strength  than  the 
fine  hard  Para  with  only  1-44  per  cent,  of  resm.  The  cause  of  this 
is  probably  to  be  sought  more  in  the  origin  of  the  rubber  than 
in  the  resin  it  contained.  The  same  properties  were  also  observed 
in  Adeli  balls,  Lewa  rubber,  and  Soudan  twists,  although  the^- 
did  not  contain  such  a  high  percentage  of  resin  as  the  Mozambique 
balls.'  It  is  therefore  concluded  from  these  experiments  that,  if 
the  amount  of  resin  does  not  exceed  7  per  cent.,  it  does  not  have 
an  injurious  effect  upon  vulcanization,  but  when  over  this  amount 
it  tends  to  prevent  complete  vulcanization  of  the  rubber.  At 
the  same  time  the  origin  of  the  rubber  is  also  of  great  importance 


PARA     RUBBER  435 

in  this  respect.  More  accurate  information  on  this  subject, 
however,  would  be  obtained  by  vulcanizing  Para  rubber,  for 
instance,  with  increasing  amounts  of  resin  extracted  from  one 
quality  of  rubber.  Accordingly,  experiments  were  eventually 
carried  out  in  the  following  way  :  fine  hard  Para  containing 
3-28  per  cent,  of  resin  was  well  washed  and  dried,  mixed  in  five- 
gram  lots  with  10  per  cent,  of  sulphur,  and  worked  up  with  in- 
creasing quantities  of  Congo  resin,  extracted  from  finest  black 
Upper  Congo  rubber  with  acetone.  Ten  such  samples  were 
vulcanized  for  45  minutes  at  145°  C,  under  a  pressure  of  4-5 
atmospheres,  then  dried,  and  subjected  to  physical  tests.  With 
the  proportion  of  added  resin  rising  from  3-30  per  cent.,  the 
breaking  strain  fell  from  9  kilos  to  3,  whilst  the  extensibility  of 
the  rubber  rose  from  3-9  to  5-7.  The  first  five  samples  (3-15  per 
cent,  added  resin)  were  well  vulcanized,  the  remainder  were 
vulcanized  throughout,  but  became  gradually  softer  as  the  pro- 
portion of  resin  increased. 

The  percentage  of  resins  in  plantation  rubber  and  in  fine  hard 
Para  is,  however,  usually  much  smaller  than  in  many  of  the  other 
rubbers  here  mentioned,  and  the  injurious  effect  of  excess  of  resins 
may,  as  far  as  rubber  growers  are  concerned,  be  dismissed. 

Value  of  Resins  in  Rubber. 

It  has  been  shown  that  the  amount  of  resin  in  various  samples 
of  rubber  varies  considerably ;  even  in  different  samples  known 
under  the  same  name  the  quantity  may  vary  quite  50  per  cent. 
As  to  the  value  of  rubber  freed  from  resin,  opinions  are  somewhat 
at  variance.  The  Rheinischer  Gummiwerke — (cf.  I.R.J.,  Feb. 
1907) — claim  to  be  able  to  place  on  the  market  a  rubber  which 
for  all  technical  purposes  may  be  considered  free  from  resin.  An 
examination  of  these  resin-free  rubbers  has  been  made  by  Drs. 
Frank,  Marckwald  and  Leibschiitz  with  the  object  of  determining 
whether  the  extraction  of  the  resins  from  washed  crude  rubber 
influences  the  manufacturing  process  favourably  or  unfavourably. 
They  report  that  the  sheets  of  rubber  obtained  in  the  ordinary 
way  from  the  extracted  rubber  are  in  every  case  less  sticky  and 
more  uniform  than  those  from  non-extracted  material.  Further, 
the  extracted  rubber  was  described  as  being  brighter  in  appearance 
and  the  smell  characteristic  of  the  several  brands  had  invariably 
disappeared.  Physical  tests  were  also  made  both  with  the  ex- 
tracted and  non-extracted  rubbers.  Various  brands  of  upper 
Congo,  Madagascar  and  Gambia  rubbers  were  employed  for  these 
determinations,  containing  varying  amounts  of  resin,  ranging 
from  4  to  38  per  cent.,  which  after  extraction  were  reduced  from 
2  to  9  per  cent. 

As  a  result  of  their  experiments  on  the  rubbers  from  which  the 
greater  part  of  the  resins  had  been  extracted,  they  concluded 
that :  (i)  The  specific  smell  of  the  raw  material  is  removed  ; 
(2)  its  stickiness  also  disappears  completely  by  extraction  of  the 
resins,  thus  materially  assisting  mixing  operations  ;   (3)  the  solidity 


436  PARA     RUBBER 

of  vulcanized  goods  made  from  extracted  rubbers  of  typical 
bad  qualities  is  invariably  greatly  superior,  being  sometimes 
as  much  as  50  per  cent,  better  than  the  non-extracted  rubber,  and 
(4)  the  extraction  of  resin  facihtates  uniform  qualities  being 
supplied. 

The  removal  of  resins  from  rubbers  in  this  way  is  of  more 
interest  to  those  planters  concerned  with  Para  rubber  in  the  wild 
state  or  with  other  American  and  African  rubbers  containing 
large  proportions  of  resins.  It  is,  however,  a  subject  of  interest 
to  all  rubber  growers  as,  besides  producing  the  advantages  already 
mentioned,  it  would  effect  a  reduction  in  cost  of  transport  and 
be  of  importance  to  the  manufacturer.  Pure  plantation  rubber 
containing  less  than  4  per  cent,  of  resin  would,  however,  not 
require  such  treatment. 

Desirable  Quantities  of  Resin. 

During  the  discussion  upon  a  lecture  by  Schidrowitz  (Society 
of  Chemical  Industry,  May  i6th,  1910)  Colonel  Birley  said  that 
the  manufacturers  required  a  minimum  of  resin,  and  that  this 
should  be  as  hard  as  possible.  A  httle  resin  of  the  right  t5rpe 
does  no  harm  in  rubber.  Good,  hard  resin  had  no  prejudicial 
effect  per  se,  if  there  is  not  more  than  6  to  8  per  cent. 

Other  views  upon  these  points  were  expressed  at  the  Con- 
ference held  in  connection'with  the  Rubber  Exhibition  of  igii.- 
According  to  Potts,  it  is  immaterial,  speaking  generally,  to  the 
manufacturer  what  the  percentage  of  resin  is  within  i  or  2  per  cent. 
Frank  thought  that  the  percentage  of  resin  may  or  may  not  be 
significant  according  to  the  nature  of  the  resin,  provided  it  lies 
within  the  right  limits  for  that  particular  rubber.  There  are 
hard  and  soft  resins.  The  former  are  generally  more  objectionable. 
The  chairman  of  the  meeting  said  that  the  manufacturer  does  not 
care  whether  there  is  3  or  6  per  cent,  of  resin. 

Crepe  from  Jelutong. 

Probably  one  of  the  most  recent  commercial  developments 
of  importance  in  this  direction  is  the  conversion  of  sticky  jelutong 
from  Dyera  trees  into  first-class  crepe,,  comparable  in  many 
respects  with  that  from  Hevea  plantations.  Developments 
upon  similar  hues  have  been  recorded  with  highly-resinous  pro 
ducts  obtained  from  Euphorbia  Tirucalli  in  Africa.  It  appears 
quite  possible,  if  prices  for  raw  rubber  are  maintained  at  a  high 
level,  that  supplies  may  be  appreciably  augmented  by  the  extrac- 
tion of  resins  from  products  hitherto  regarded  as  insignificant 
sources  of  rubber. 

A  Resin-Extracting  Machine. 

A  very  heavily-built  mixing  and  masticating  machine,  equipped 
with  a  jacketted-trough  which  can  be  heated  or  cooled  by  steam 
or  water,  and  also  fitted  with  attachments  so  that  the  gums  can 


PARA     RUBBER  437 

be  treated  in  vacuo,  is  made  by  Messrs.  Werner,  Pfleiderer  and 
Perkins. 

Freshly- washed  jelutong  is  taken  in  its  wet  condition  and 
put  into  this  machine,  which  dries  it  thoroughly,  rapidly, 
and  automatically  ;  when  dry  the  resin  solvent  is  introduced 
and  well  incorporated  with  the  jelutong.  When  the  resin  is 
dissolved,  the  solution  is  sucked  out  through  a  pipe  and  the 
rubber  left  behind.  The  rubber,  which  still  contains  a  quantity 
of  spirit,  can  then  be  washed  clean  in  the  same  machine.  In 
addition  the  machine  will  extract  the  solvent  from  the  resin 
solution  as  a  secondary  process. 

Proteins. 

The  proteins,  which  either  alone,  or  with  other  substances, 
lead  to  putrefaction,  exist  almost  entirely  in  solution  in  the  fresh 
latex.  In  the  rubber  they  are  reputed  to  be  responsible  for 
much  tackiness,  for  the  evolution  of  obj  ectionable  fumes  during 
hot  vulcanization,  and  also  for  certain  cases  of  "blowing"  in 
vulcanization.  Their  removal  from  latex  as  well  as  rubber  has 
often  been  discussed  and  .many  experiments  have  been  devised 
with  this  object  in  view. 

Removal  of  Proteins. 

Weber  suggested  that  an  expeditious  method  would  be  to 
centrifugalize  the  solutions,  a  method  which  has  been  dealt  with 
when  describing  the  machines  used  in  preparing  and  purifying 
rubber. 

The  addition  of  formaldehyde  to  some  latices  is  supposed 
(i)  to  prevent  the  coagulation  of  the  proteins  and  (2)  to  cause  the 
rubber  to  collect  on  the  top  of  the  mixture.  The  proper  applica- 
tion of  this  re-agent  to  Castilloa  latex  is  said  to  free  the  rubber 
from  every  trace  of  proteins.  It  has,  however,  been  questioned 
whether,  or  not,  the  caoutchouc  would  coagulate  or  even  coalesce, 
if  all  proteins  were  removed  from  the  latex. 

There  is  a  slightly  higher  percentage  of  proteins  and  resins  in 
Hevea  rubber  from  young  than  in  that  from  old  plants.  The 
poor  physical  properties  of  young  plantation  rubber  may  be 
ultimately  associated  with  the  proportion  of  these  constituents. 

Torrey  (Indiarubber  Exhibition  Lectures,  1908)  suggests  a 
method  of  getting  rid  of  a  large  proportion  of  the  proteins. 
After  thorough  cutting-up,  wash  with  cold  water,  following  with, 
say,  a  48  hours'  soaking  in  a  caustic  soda  solution  of  perhaps 
2  per  cent,  strength.  He  points  out  that,  during  vulcanization, 
sulphuretted  hydrogen  is  evolved  by  the  action  of  the  sulphur 
upon  the  proteins.  It  is  certain  that  many  of  the  obstinate 
cases  of  blowing  or  porosity  in  rubber  goods  may  be  traced  to  this 
cause.  Furthermore,  when  these  proteins  are  exposed  to  the 
ordinary  vulcanizing  temperatures  in  contact  with  basic  sub- 
stances, such  as  occur  among  the  ordinary  compounding  materials, 
decomposition  is  almost  certain,  and  will  be  accompanied  by 
evolution  of  ammonia,  and  perhaps  other  gases. 


438  PARA     RUBBER 

Thorough  washing  and  drying  of  the  rubber  is  generally 
all  that  is  necessary  to  prevent  the  decomposition  of  the 
protein.  The  protein  in  fine  hard  Para  is  said  to  be  more  or  less 
immune  to  the  action  of  putrefactive  bacteria  on  account  of  the 
presence  of  cresol. 

Distribution  of  the  Proteins. 

Spence  has  shewn  that  protein  is  the  substance  which  Weber 
regarded  as  an  oxygen-addition  compound  of  rubber,  and  that 
the  so-called  insoluble  constituent  is  in  every  case  the  protein 
of  the  latex.  The  jelly-Kke  residue  left  when  rubber  has  been 
dissolved  in  such  solvents  as  chloroform,  toluol,  etc.,  was  not 
examined  by  Weber  for  nitrogen  ;  had  this  been  done  it  would 
have  led  to  the  identification  of  protein.  Spence  states  that  the 
conception  of  a  protein  film  around  each  caoutchouc  globule, 
as  outhned  by  Weber,  is  no  longer  necessary  to  account  for  the 
peculiar  structure  and  stability  of  the  caoutchouc  globule.  He 
found  that  by  digesting  the  latex  of  Hevea  hrasiliensis  with  trypsin, 
more  than  half  of  the  protein  in  latex  can  be  afterwards  removed 
without  coagulation  taking  place.  Its  distribution  depends 
largely  on  the  method  of  coagulation  employed,  a  fact  which  may 
explain  the  difference  in  tensile  strength  between  fine  hard  Para 
and  plantation  rubber.  Parkin  urges  that  what  militates  against 
this  view  is  that  in  mastication  and  vulcanization  such  structure 
must  most  likely  disappear. 

The  following  researches  upon  the  distribution  of  protein 
in  fine  hard  Para  were  made  by  Spence  (Quarterly  Journal,  In- 
stitute Commercial  Research,  Liverpool  University,  1907).  At 
first,  samples  were  repeatedly  digested  in  chloroform  over  long 
periods  for  the  extraction  of  the  caoutchouc  hydrocarbon,  as  far  as 
that  was  possible.  Some  of  the  jelly-like  residue,  which  dries 
in  bulk  to  a  hard,  tough,  almost  friable  brown  mass,  was  spread 
upon  a  microscopic  slide,  and  was  compressed  into  a  thin  film. 
This  film  was  allowed  to  dry,  when  it  was  examined  under  a  low 
power  of  the  microscope.  "Fibrous-looking  threads  running 
in  all  directions,  as  if  the  material  had  contracted  on  itself,  leaving 
clear  spaces  covered  with  thin  films  of  what  appeared  to  be  caout- 
chouc, were  readily  discernible. ' '  One  may  remark  that  any 
gelatinous  or  colloidal  substance,  when  dried,  is  perhaps  likely 
to  show  this  appearance.  Spence  turned  next  to  the  examination 
of  sections  of  raw  rubber,  in  which,  by  a  certain  method,  a  deposit 
of  metallic  silver  brought  into  view  a  fibrous  or  thread-liite  structure 
running  through  the  mass.  He  considered  that  here  was  the 
protein. 

What  we  desire  to  know  from  such  a  research  is  the  exact  and 
minute  relationship  between  the  individual  caoutchouc  globules 
and  the  protein,  and  it  cannot  be  said  that  Spence's  methods 
were  efficient  from  this  point  of  view.  He  suggests  that  when 
the  raw  rubber  is  digested  in  chloroform,  the  latter  passes  through 
the  protein   and   is   absorbed  by   the   caoutchouc    hydrocarbon. 


PARA     RUBBER  439 

which  becomes  enormously  increased  in  bulk,  but  cannot  escape, 
even  as  a  solution,  through  the  protein.  The  protein  walls  of 
the  cavities  must,  therefore,  become  greatly  stretched ;  and 
it  is  by  their  eventual  rupture  that  the  caoutchouc  solution 
escapes.  It  is  unfortunate  that  Spence  bases  his  decision  upon 
the  examination  of  such  a  distended  and  ruptured  protein  mesh- 
work. 

Notes  on  Proteins  by  Spence. 

To  the  above  account  of  proteins  in  crude  rubber  I  desire  to 
add  a  series  of  notes  which  Dr.  Spence  has  been  good  enough  to 
compile  for  me  : — 

"The  nitrogen  of  rubber  is  not  entirely  of  protein  origin  as 
has  been  usually  held,  and  we  must  distinguish  between  protein- 
nitrogen  and  the  nitrogenous  bodies  of  the  acetone-extract  which 
are  of  well  defined  alkaloidal  character  and  are  readily  isolated 
by  suitable  means  from  Para  rubber  or  its  acetone-extract.  The 
distribution  of  the  nitrogen  in  some  samples  of  Para  rubber  is 
shewn  in  the  following  table  : — 


1.  of  Sample. 

Nitrogen  in 

Acetone-Extracted  Para 

Rubber. 

Nitrogen  in 
Acetone  Extract. 

I 
2 
3 

0.44% 

0.367% 

0.356% 

0.297% 

0-50% 
0.41% 

"The  protein  or  'insoluble'  nitrogen  of  rubber  has,  until 
recently,  received  but  scant  attention.  Recently,  however,  its 
importance  has  become  more  recognized.  In  the  case  of  Para 
and  of  some  other  rubbers,  I  have  shown  that  this  insoluble  protein 
e'xists  in  the  rubber  as  a  fibrous  network-like  structure  which  can 
be  made  evident  by  a  suitable  method  of  staining.  Protein  is 
present  in  greater  or  less  amount  in  all  latices  and  invariably 
becomes  bound  up  in  the  rubber  clot  when  the  latex  is  coagulated, 
unless  special  methods  are  adopted  whereby  the  protein  is 
eliminated  before  the  final  coagulation  takes  place.  It  is  ex- 
ceedingly difficult,  however,  if  not  well  nigh  impossible,  to  remove 
the  entire  nitrogen  from  rubber  in  this  way,  and  numerous 
experiments  conducted  with  the  object  of  removing  the  entire 
nitrogen  from  the  latex  have  been  only  partially  successful. 
Indeed,  there  can  be  no  doubt  that  the  protein  of  the  latex, 
colloidal  in  character  as  it  is,  is  one  of  the  most  important  elements 
in  determining  1he  stability  of  a  latex  on  the  one  hand,  and  the 
ease  with  which  it  can  be  coagulated  by  certain  coagulants  on  the 
other.  The  influence  of  this  'protective'  colloid  (Schutzkolloide) 
in  problems  of  coagulation  is  too  well  known  to  require  mention 
here,  but  to  those  who  have  the  practical  problem  of  latex  coagula- 
tion before  them  each  day,  no  more  fruitful  field  of  investigation 
could  be  found  than  that  of  the  influence  of  various  protective 
colloids  on  the  stabihty  of  latex  emulsions. 

' '  That  it  is  well-nigh  impossible  to  remove  the  entire  protein 
from  the  latex  is  probably  due  to  the  fact  that  it  is  adsorbed,  at 


440  PARA     RUBBER 

least  partially,  by  the  latex  emulsion.  That  these  globules  are 
surrounded  by  a  film  of  protein  in  the  sense  as  Weber  at  one  time 
suggested,  we  have  as  yet  no  satisfactory  proof,  nor  does  the 
existence  of  such  a  protein  sheath  around  each  globule  appear  to 
be  necessary  to  explain  the  existing  facts. 

' '  The  proteins  of  rubber  appear  to  belong  to  the  class  of  the 
glyco-proteins  rather  than  to  the  simple  proteins.  The  nitrogen 
contained  in  these  proteins  is  very  much  less  than  that  in  the 
simple  proteins  by  reason  of  the  large  carbohydrate  complex 
attached  to  the  former.  This  complex  can  be  split  off  and  plays 
a  not  unimportant  role  in  the  latex  as  well  as  in  the  rubber  derived 
from  it.  But  we  have  no  reason  to  believe  that  the  protein  of  the 
various  rubbers  is  all  alike.  On  the  contrary,  differences  in  the 
nature  of  the  protein  in  different  rubbers  probably  accounts  to 
some  extent  for  differences  in  the  ease  with  which  the  various 
latices  are  coagulated. 

"That  the  insoluble  constituent  of  rubber  is  of  protein 
character,  and  is  not  a  carbohydrate  as  Weber  suggested,  I  have 
endeavoured  in  various  publications  to  show.  The  reactions  of 
the  insoluble  constituent,  the  action  of  the  enzyme  trypsin  on  the 
same,  and  the  peculiar  staining  properties  of  the  substance,  all 
stand  to  confirm  this  belief. 

"The  retarding  influence  of  the  insoluble  constituent  on  the 
process  of  solution  of  raw  rubber  in  solvents  is  recognized.  I  have 
endeavoured  to  explain  its  influence  in  this  connection  by  a 
theory  based  on  its  peculiar  distribution  in  the  form  of  a  network 
of  microscopic  fibres  running  throughout  the  mass,  this  network 
being  pervious  to  solvents  but  impervious  to  the  colloidal  rubber 
solution.  If  this  network  is  destroyed  by  working  the  rubber  on 
the  mill,  the  complete  solution  of  the  rubber  is  hastened.  Whether 
this  simple  mechanical  theory  will  serve  to  explain  all  the 
phenomena  observed  in  the  preparation  of  a  rubber  solution  or 
not  is  still  doubtful.  The  fact,  however,  that  the  complete 
destruction  of  the  protein  fibre  in  raw  rubber  by  mechanical  means 
greatly  facilitates  the  preparation  of  a  hom.ogenous  solution  of  the 
same  goes  far  to  show  that  the  apparent  retarding  influence  of  the 
protein  fibre  on  the  rate  of  solution  is  of  a  mechanical  rather 
than  of  a  chemical  or  a  physical  nature. 

"From  the  analytical  standpoint,  the  protein  impurities 
in  rubber  are  of  even  more  importance  than  the  resins  themselves, 
for  these  are  readily  extracted  and  determined,  whereas  the 
quantitative  separation  of  rubber  from  protein  or  of  protein  from 
rubber  is  a  much  more  troublesome  task.  It  is  interesting,  how- 
ever, to  note  that  the  importance  of  the  protein  fibre  in  this 
connection  is  to-day  recognised  by  those  most  active  in  advancing 
methods  for  the  chemical  analysis  of  rubber.  The  separation  of 
the  protein  from  a  rubber  solution  by  filtration  or  by  centrifugaliza- 
tion  is  barely  possible.  On  the  other  hand,  I  have  found  that 
these   nitrogenous   elements    of   rubber   can    be    almost    entirely 


PARA     RUBBER  441 

eliminated  by  saponification  with  alcoholic  alkali  under  suitable 
conditions. ' ' 

I  have  quoted  the  above  from  Dr.  Spence  in  detail  in  order 
that  no  misconception  may  arise  as  to  that  scientist's  views  on  this 
important  constituent  of  rubber. 

Ash. 

This  impurity  is  present  in  almost  negligible  quantities — 
o-i8  to  0-5  per  cent.  Generally,  Para  rubber  contains  0-3  per  cent, 
of"  ash,  as  against  o-2  per  cent,  in  other  rubbers.  Weber  is  respon- 
sible for  the  statement  ' '  that  it  may  yet  be  possible  to  chemically 
identify  the  brand  of  indiarubber  from  ash  analyses."  Lime  is 
said  to  predominate  in  Para  rubber,  magnesia  in  Ceara,  and  ferrous 
oxide  in  African  rubbers.  The  presence  of  the  ash  impurities  is 
undesirable  on  account  of  their  tendency  to  interfuse  with  the 
indiarubber  and  the  resinous  constituents  during  the  processes  of 
manufacture. 

Spence,  as  a  result  of  his  analyses  (LR.J.,  Sept.,  1907),  of 
Funtumia  rubber,  concludes  that  the  ash  in  a  sample  of  washed 
rubber  is  remarkably  constant  in  quantity,  and  supports  Weber's 
suggestion  that  the  ash  contents  might  be  employed,  when  ex- 
haustive investigation  of  the  quantitative  composition  of  the  ash 
of  the  various  brands  has  been  made,  as  a  chemical  method  of 
distinguishing  washed  rubber  from  different  sources.  The  con- 
stancy of  the  mineral  constituents  in  washed  rubber  is  a  point 
of  considerable  importance. 

Potassium  in  Washed  Rubber. 

Spence  in  his  concluding  paragraph  states  ' '  that  the  per- 
centage of  potassium  salts  to  be  found  in  a  sample  of  washed 
rubber  from  Funtumia  elastica  may  be  taken  as  an  indication  of 
the  purity  of  the  rubber  and  the  efficiency  of  the  washing  process. 
Whether  the  same  applies  to  washed  Para  rubber  has  not  yet  been 
stated  by  chemists. 

Potassium,  though  it  is  the  chief  mineral  constituent  in  the 
ash  from  the  latex,  disappears  from  the  coagulated  rubber  in  the 
process  of  washing.  In  a  sample  of  Funtumia  elastica  latex  it 
was  present  in  the  form  of  soluble  salts  of  inorganic  and  organic 
acids  and  composed  about  75  per  cent,  of  the  ash  of  the  latex  on 
incineration. 

Action  of  Chemical  Agents  on  Rubber. 

The  effects  of  various  chemical  agents  upon  crude  and  manu- 
factured rubbers  have  been  observed.  In  the  latter  these  are 
modified  according  to  the  nature  of  the  compounding  ingredients 
used,  and  of  the  process  of  vulcanization.  An  attempt  is  here 
made  to  isolate  the  facts  relating  to  the  effects  of  chemical  agents 
on  crude  rubber  alone. 

Alkalies  have  not  a  pronounced  action  upon  rubber  at  low 
temperatures.     Heinzerling  states  that  on  prolonged  digestion  with 


442  PARA     RUBBER 

ammonia  the  rubber  passes  into  the  state  of  an  emulsion,  in 
appearance  closely  resembling  rubber  latex. 

Copper  and  its  salts  have  very  pronounced  effects  upon  rubber, 
and  rapidly  bring  about  its  decay.  They  accelerate  the  rate 
of  oxidation  of  rubber. 

The  effect  of  chlorine,  bromine,  and  iodine  on  rubber  is 
very  complicated,  and  for  a  full  knowledge  of  the  various  changes 
which  are  induced  by  their  action  reference  must  be  made  to  Weber 
(pp.  31-37).  Acids  exert  a  strong  action  on  indiarubber.  Strong 
sulphuric  acid  chars  rubber  on  heating.  Strong  nitric  acid 
attacks  it  vigorously,  forming  at  first  a  yellow  compound 
which  is  subsequently  decomposed. 

Rubber — crude  or  vulcanized — tends  to  become  hard  and 
brittle  under  the  action  of  oxygen  in  the  air.  Thus,  thin  vulcan- 
ized goods  may  oxidise  eventually  to  a  plastic  condition,  and 
finally  to  a  brittle  product  capable  of  being  powdered,  the  addition 
of  oxygen  to  the  caoutchouc  molecule  resulting  in  the  formation 
of  resinous  bodies  of  which  Spiller's  resin  is  the  best  known.  This 
oxidation  is  encouraged  by  light,  and  by  the  presence  of  small 
quantities  of  copper  or  of  its  salts,  and  also  of  oils. 

While  rubber  does  not  readily  react  with  many  common 
reagents,  it  does  to  a  surprising  degree  with  sulphur  in  its  various 
forms,  the  process  of  combination  being  commonly  spoken  of 
as  vulcanization.  Pure  sulphur  does  not  combine  with  rubber 
at  temperatures  below  270°  F.,  but  sulphur  mono-chloride  readily 
reacts  with  it  at  ordinary  temperatures,  a  fact  that  is  taken 
advantage  of  in  cold  vulcanization. 

Action  of  Oils  on  Rubber. 

Rubber  dissolves  in  mineral  oils  (benzene,  toluene,  petroleum 
spirit,  etc.),  in  ether,  chloroform,  carbon  tetra-chloride  and 
disulphide,  in  essential  oils  (turpentine,  terebene,  etc.),  and  in 
certain  fatty  oils  (neatsfoot  oil,  sperm  tallow).  Other  fatty  oils 
cause  it  to  swell  up.  Though  preparations  of  fatty  oils  are  used 
in  rubber-compounding  in  Small  quantities,  all  oils"  are  injurious, 
and  may  reduce  the  rubber  to  a  sticky  mass  if  not  in  amount 
sufficient  to  dissolve  it.  An  additional  effect,  about  which 
there  is  some  doubt,  is  the  acceleration  of  oxidation. 

The  danger  from  lubricating-oil  in  the  washing  machines  is 
avoided  by  lengthening  the  rollers  or  by  other  devices. 

Action  of  Heat  and  Cold  on  Rubber. 
Rubber  becomes  sticky  when  subjected  to  high  temperatures, 
assuming  also  a  soft  and  plastic  condition.  At  from  170°  to 
180°  C.  it  becomes  more  or  less  fluid.  When  heated  to  the  melting- 
point  only,  it  afterwards  remains  soft  and  adhesive  on  coohng, 
but  hardens  when  spread  out  in  thin  layers.  At  200°  C.  it  is 
converted  into  a  sticky  mass  that  does  not  harden  on  coohng ; 
Ditmar  puts  the  melting-point  for  fine  hard  Para  at  188°  C.  The 
melting-point,  if  rubber  can  be  said  to  have  one,  is  higher  than 


PARA     RUBBER  443 

this  if  the  resin  has  been  extracted.  It  is,  therefore,  obvious 
that  all  drying  and  coagulating  processes  adopted  on  plantations 
or  elsewhere  should  be  so  devised  as  to  ensure  the  temperature 
being  efficiently  regulated.  A  maximum  temperature  consider- 
ably below  that  just  quoted  should  be  guaranteed  in  any  patent 
appliances. 

Manufactured  articles,  if  exposed  to  high  temperatures,  are 
apt  to  lose  their  strength,  and  to  develop  either  sticky  or  brittle 
properties. 

When  submitted  to  low  temperatures,  rubber  loses  its  softness 
and  distensibility,  becoming  hard  and  rigid  before  the  freezing 
point  of  water  is  reached. 

Action   of   Light   on    Rubber. 

Experience  and  experiment  have  shown  that  rubber  is 
injuriously  affected  by  light,  the  rays  most  deleterious  being  the 
ultra-violet  or  actinic  (chemical)  rays.  In  order  to  determine 
more  fully  the  effects  of  actinic  light  upon  rubber,  Henri  (le 
Caoutchouc,  1910,  p.  4371),  submitted  some  sheets  of  crude  and 
vulcanized  rubber  prepared  in  different  ways  to  the  action  of  a 
mercury  vapour  lamp.  Kept  about  8  inches  away  from  the 
sheets,  an  exposure  of  20  hours  was  sufficient  to  produce  visible 
deterioration  in  the  crude  samples  ;  the  rubber  darkened  and 
became  shiny,  cracking  at  the  surface  when  stretched.  In  the 
case  of  dark-brown  cut-sheet,  the  action  was  only  superficial  ;  but 
it  proceeded  more  deeply  in  the  case  of  paler  samples.  Vulcanized 
rubber  took  a  longer  time  to  deteriorate — as  long  as  from  48  to  72 
hours.  Experiments  performed  in  the  absence  of  oxygen  showed 
that  the  latter  was  essential  to  the  change,  and  therefore  that  the 
process  was  one  of  oxidation  under  the  influence  of  the  actinic 
rays. 

Enough  has  been  said  to  show  the  importance  of  keeping 
crude  rubber  away  from  the  light,  or  at  least  of  keeping  it  in 
rooms  the  light  for  which  has  been  filtered  through  red-coloured 
glass. 

Absorption   of  Water  and  Gases. 

Though  rubber  is  insoluble  in  water,  it  rapidly  swells  when 
immersed  in  it  and  absorbs  a  considerable  amount  of  the  liquid,  the 
actual  amount  capable  of  being  absorbed  increasing  with  a  decrease 
in  the  resin  and  oily  substances.  On  this  account  rubber  from 
young  trees  may  perhaps  be  roughly  detected  by  the  water  capacity 
of  the  sample  of  rubber,  allowing  for  normal  variations.  When 
vulcanized  the  water  absorption  power  is  small. 

Gases  diffuse  through  rubber  ;  they  are  also  partly  retained, 
the  rubber  having  the  power  of  absorbing  and  holding  them. 

General   Properties  of  Rubber. 

The  specific  heat  of  rubber,  as  determined  by  Terry  and  Gee, 
is  0-84 — the  same  as  that  of  turpentine.  It  is  a  slow  conductor 
of  heat  and  stands  high  as  an  electrical  insulator. 


444  PARA     RUBBER 

Beadle  and  Stevens  (Chemical  News,  Nov.  15th  and  21st, 
1907),  give  several  determinations  of  the  specific  gravities  of 
plantation  rubbers  examined  by  them.  They  show  that  the  specific 
gravity  of  apparently  similar  biscuits,  blocks,  etc.,  may  vary 
according  to  the  method  employed  in  the  preparation  of  rubber, 
those  having  a  large  proportion  of  air  bubbles  or  which  have  not 
been  severely  pressed  being  Ughter  than  others.  The  Values  are  : 
block,  0-96  ;  biscuit,  0-919  ;  and  fine  hard  Para,  0-927.  The 
specific  gravity  of  fine  hard  Para  after  cleaning  has  been  variously 
estimated.  Faraday  gave  it  as  0-925  ;  Weber,  from  0-915  to 
0-931  ;  Juhan,  0-925  ;  and  Terry,  0-924.  In  Allen's  ' '  Commercial 
Organic  Analysis ' '  there  is  a  statement  to  the  effect  that  highly 
purified  rubber  has  a  specific  gravity  of  0-911  at  17°  C,  and  the 
technically  pure  substance  from  0-915  to  0-931. 

Rubber  is  almost  incompressible  ;  that  is,  it  retains  its  original 
volume  under  pressure. 

The  mechanical  properties  of  rubber  are  incidentally  con- 
sidered in  the  part  of  this  chapter  dealing  with  the  methods  of 
testing,  though  some  reference  may  here  be  specially  made  to  the 
nature  of  ' '  nerve. ' ' 

The  Nature  of  "  Nerve." 

The  word  ' '  nerve ' '  is  used  in  reference  to  the  usual  physical 
and  mechanical  properties  of  raw  rubber.  Mastication  or  heating, 
resulting  in  the  production  of  soft  rubber,  is  said  to  destroy,  for 
the  time  being,  the  "nerve"  of  rubber.  This  quality  of  crude 
rubber  is  credited  by  Schidrowitz  to  mechanical,  physical,  and 
chemical  factors.  The  mechanical  factors  referred  to  are,  in  the 
case  of  fine  hard  Para,  the  film  structure  due  to  the  method  of 
coagulating  in  succession  layers,  and  the.  fibrous  network  of 
protein.  By  the  physical  he  means  largely  the  consistency  of  the 
caoutchouc  globules.  The  chemical  factor  is,  of  course,  the  state 
of  polymerization  of  the  rubber  molecule.  He  has  stated  that  there 
was  no  doubt  in  his  mind  that  the  great  nerve  of  fine  hard  Para  is 
due  partly  to  the  method  of  coagulation  in  concentric  layers. 
The  smoking  and  drying  of  one  thin  layer  upon  another  in  endless 
succession  may,  in  his  opinion,  be  compared  to  the  manufacture 
of  wire-wound  artillery.  It  is  well  known  that  the  strength  of  a 
gun  built  up  by  tightly  winding  wire  round  a  core  is  much  greater 
than  that  of  a  solid  cast  or  forged  mass.  In  a  later  deliverance 
he  puts  forward  the  opinion  that  the  mechanical  structure  of  the 
crude  rubber — referring  to  the  film  structure  and  the  protein 
network — is  probably  of  little  utility,  as  it  is  very  largely  broken 
down  upon  the  washing  and  mixing  mills.  The  physical  nerve 
depends  upon  the  colloidal  state  of  the  caoutchouc  hydrocarbon. 
And  this  depends  largely,  if  not  entirely,  upon  the  state  of  poly- 
merisation ;  that  is,  it  is  a  function  of  the  chemical  nerve.  The 
chemical  nerve  is  a  very  important  factor  and  varies  probably 
according  to  the  species  of  the  tree,  the  method  of  coagulation,  etc. 
As  Schidrowitz  suggests,  chemical  nerve  being  to  a  great  extent 


PARA     RUBBER  445 

a.  question  of  the  quality  of  the  latex,  and  this  in  turn  being 
partly  dependent  on  the  age  of  the  tree,  it  is  obvious  that  the 
quality  or  nerve  of  plantation  rubber  must  improve  as  time  goes  on. 

Tackiness  in  Rubber. 

The  majority  of  planters,  even  if  they  have  only  just  com- 
menced to  tap  their  rubber  trees,  know  what  tackiness  in  planta- 
tion rubber  means.  In  the  mild  form  it  presents  itself  in  the 
drying-shed  as  a  sticky  appearance  on  the  surface  of  rubber.  In 
some  cases  it  does  not  make  its  appearance  until  the  rubber  has 
been  packed  and  despatched  to  Europe.  Frequently,  however, 
the  rubber  in  the  drjdng-house  practically  resolves  itself  into  a 
syrupy  liquid.  In  fact,  tacky,  or  as  it  is  sometimes  called,  heated 
rubber,  is  sold  more  as  a  by-product.  Tackiness  has  been  known 
for  many  years  on  plantations,  and  has  also  been  known  to  manu- 
facturers even  in  the  vulcanized  material.  In  these  notes  tacki- 
ness as  it  occurs  on  plantations  is  dealt  with.  It  is  a  subject  of  more 
than  ordinary  importance  to  every  producer  in  the  tropics  and 
to  estate  proprietors. 

At  the  present  time  it  is  known  that  various  agents  may  bring 
about  this  undesirable  condition,  and  it  is  doubtful  whether  many 
experts  can  be  found  who  will  be  bold  enough  to  state  that  any  one 
agent  is  solely  responsible.  From  a  study  of  the  researches  of 
various  authorities  it  can  be  concluded  that  this  condition  is  due 
to  several  causes  acting  sometimes  alone,  and  on  other  occasions 
conjointly.  The  agents  which  hitherto  have  been  associated  with 
this  sticky  development  of  rubber  may  be  grouped  under  the 
following  heads  :  (i)  bacterial ;  (2)  sunhght ;  (3)  heat ;  (4)  chemical. 

Already  the  effects  upon  crude  rubber  of  some  of  these  agents 
have  been  considered,  but  tackiness  is  a  condition  that  deserves 
separate  discussion,  especially  as  we  cannot  always  be  certain  of 
the  specific  cause  or  causes. 

Bacteria  and  Tackiness. 

When  tackiness  was  first  studied  in  Ceylon  it  was  stated 
to  be  almost  entirely  due  to  the  development  of  bacteria  upon 
or  in  the  rubber,  and  as  a  means  of  overcoming  this  it  was  suggested 
that  all  affected  specimens  should  be  immediately  isolated,  and 
that  in  order  to  avoid  the  frequent  appearance  of  this  disease, 
the  whole  of  the  factory  and  utensils  should  be  periodically 
disinfected.  As  a  result  of  these  measures  in  some  quarters  it  was 
stated  that  the  disinfecting  of  the  factory  had  resulted  in  a 
reduction  of  tacky  rubber. 

That  some  cases  of  tackiness  are  due  largely,  if  not  entirely, 
to  the  action  of  bacteria,  producing  putrefaction  of  the  proteins 
in  rubber,  is  admitted.  The  fermentation  of  the  sugars  and 
other  carbohydrates  possibly  also  plays  a  part.  The  first  rubber 
from  old  trees  or  that  from  young  trees  seems  very  liable  to  undergo 
putrefactive  changes.  Now,  such  rubbers,  or  the  original  latices, 
visually  possess  a  high  percentage  of  proteins  and  carbohydrates, 


446  PARA     RUBBER 

which  render  the  conditions  for  the  development  of  bacteria  more 
favourable.  Furthermore,  analyses  of  tacky  rubber  show  a  high 
percentage  of  proteins. 

The  relation  of  the  protein-content  to  tackiness  is  indicated 
in  the  analyses,  made  in  Ceylon  (Committee  Agric.  Exper.,  Pera- 
deniya,  1905),  of  sound  rubber  and  material  in  various  degrees 
of  tackiness  ; — 

Sound  Rubber.     Tacky.  Tacky.     Very  Tacky. 


0/ 
/o 

% 

/o 

% 

Moisture 

0-30 

0-36 

o-o6 

0-44 

Ash 

0-38 

0-28 

0-54 

072 

Resins 

2-36 

2 '32 

2-66 

3-70 

Proteins 

3-50 

3-85 

3-50 

4-90 

Caoutchouc.  . 

93-46 

loo-oo 

93-19 

93-24 

90-24 

loooo 

1 00  00 

1 00  00 

That  bacteria  play  a  part  in  tackiness  is  suggested  by  the 
fact  that  this  form  of  the  disease  can  spread  from  one  piece  of 
rubber  to  another  by  contact.  Furthermore,  fine  hard  Para 
and  smoked  rubber  from  plantations  do  not  very  frequently 
go  tacky.  The  explanation  of  this  probably  lies  in  the  presence 
of  antiseptics  in  the  smoked  rubber.  The  preventive  measures 
(if  bacteria  constitute  one  of  the  essential  factors)  to  keep  in 
view  are,  first,  to  keep  the  factory  and  all  utensils  well  disinfected, 
to  wash  and  squeeze  thoroughly  all  freshly-coagulated  rubber, 
to  dry  the  rubber  as  rapidly  as  possible  without  exposure  to  high 
temperatures,  and  occasionally  apply  formalin  to  the  latex 
or  the  surface  of  the  prepared  rubber. 

Sunlight  and  Tackiness. 

Though  sunhght  is  a  bactericide,  it  is  acknowledged  that 
tackiness  sometimes  develops  more  quickly  under  its  influence. 
Samples  of  rubber  when  exposed  to  strong  sunlight  may  become 
tacky  in  a  few  hours.  Brindejonc  submitted  some  samples  of 
Landolphia  rubber  to  the  action  of  sunlight,  diffused  hght,  heat, 
sea-salt,  and  solutions  of  weak  acids,  such  as  might  be  produced 
by  bacterial  action.  Of  these  agents  direct  sunhght  had  the 
most  deleterious  effect  ;  diffused  hght,  unless  particularly  bright, 
had  very  httle  effect.  While  the  effect  of  sunlight  in  this  direction 
cannot  but  be  admitted,  it  is  only  fair  to  say  that  in  my  of&ce 
there  are  samples  of  rubber  which  have  been  directly  exposed 
to  sunlight  since  1907.  One  is  a  specimen  of  Lanadron  block 
rubber  which  was  manufactured  in  1906,  and  part  of  which  was 
shown  at  the  Ceylon  Rubber  Exhibition ;  other  samples  are  com- 
prised of  biscuits  from  Ceylon  estates.  Not  a  single  specimen 
has  yet  shown  any  tacky  developments .  Yet  the  importance  of  this 
factor — sunlight — is  being  more  recognised  on  plantations,  and 
in  order  to  exclude  the  actinic  or  chemical  rays  of  light,  the  windows 
of  many  factories  are  being  supplied  with  ruby  or  orange-coloured 
glass. 


PARA     RUBBER  447 

Heat  and  Tackiness. 

Rubber,  when  exposed  to  high  temperatures,  becomes  soft 
and  sticky.  This  is  well  known  to  all  planters  who  have  used 
vacuum  driers,  and  to  rubber  manufacturers  generally.  It  is 
for  this  reason  that  the  temperature  of  drying  factories  is  usually 
maintained  at  a  maximum  of  between  90  and  100"  F.  Generally 
speaking,  however,  tackiness  is  not  frequently  associated 
with  heat  alone.  Heat  appears  to  have  a  more  softening  effect, 
and  if,  while  this  condition  of  the  rubber  lasts,  care  is  taken  to 
prevent  putrefactive  changes,  the  rubber  on  cooling  sets  to  the 
ordinary  consistency.  If,  however,  the  rubber  is  heated  in 
atmospheres  rich  in  organic  matter,  tackiness  may  set  in. 

Chemical  Causes  of  Tackiness. 

Like  sunlight,  chemical  agents  are  apparently  direct  causes 
of  tackiness,  acting  directly  on  the  caoutchouc  molecule  or  in- 
ducing a  chemical  state  in  which  the  molecule  tends  to  alter,  that 
is,  producing  that  condition  which  is  the  most  favourable  for  the 
chemical  changes.  Bamber  seems  to  stand  alone  in  placing  the 
responsibility  upon  the  enzymes,  but  this  is  merely  an  hypothesis, 
and  no  proof  is  adduced.  This  view  is  combated  by  Spence, 
who  has  prepared  samples  of  rubber  from  the  latex  of  Funtumia 
that  were  entirely  free  from  oxidising  enzymes,  and  yet  in  course 
of  time  became  tacky.  Spence  has  demonstrated  the  effect  in 
producing  tackiness  that  is  exercised  by  such  a  coagulant  as 
sulphuric  acid,  which  has  a  strong  effect.  Brindejonc  used  weak 
solutions  of  acids,  such  as  might  be  produced  by  bacterial  action. 
Rubber  that  had  been  soaked  in  acetic  acid  deteriorated  fairly 
rapidly  when  heated 'in  moist  air.  Curiously  enough,  this  hap- 
pened also  in  the  case  of  an  antiseptic  like  carbolic  acid,  a  fact 
that  would  tend  to  show  that  bacteria  are  not  essential,  or  at 
any  rate,  that  their  action  is  an  indirect  one.  The  change  also 
took  place  in  rubber  steeped  previously  in  salt  solution. 

Fox,  and  in  this  he  is  confirmed  by  Schidrowitz,  asserted  that 
alkalies  have  in  many  cases  a  tendency  to  produce  tackiness  ;  the 
latter  states  that  organic  acids  in  strength  tend  to  produce  hard 
and  brittle,  not  soft  or  tacky,  rubber. 

Imperfect  Coagulation  as  a  Cause. 

An  explanation  of  tackiness  that  does  not  come  under  any 
of  the  above  headings  has  been  put  forward  by  Frank,  but  it  is 
purely  a  hypothetical  one.  Adopting  the  idea  that  the  caoutchouc 
hydrocarbon  changes  by  polymerisation  during  coagulation  into 
the  substance  with  which  we  are  familiar,  he  attributes  the 
abnormality  to  the  presence  of  imperfectly-polymerised  portions 
that  owe  their  existence  to  unsatisfactory  coagulation,  the  coagulant 
and  the  latex  not  being  intimately  mixed,  so  that  some  parts 
of  the  latex  do  nnt  receive  proper  treatment.  Such  other  factors 
as  heat,  light,  bacteria,  enzymes,  and  mechanical  treatment,  are 
admitted  as  possibly  accessory.     While  imperfect  and  unequal 


448  PARA     RUBBER 

coagulation  can  readily  be  admitted  as  a  factor,  and  for  this  and 
other  reasons  should  be  guarded  against,  we  shall  require,  before 
Frank's  explanation  may  be  accepted,  a  proof  that  polymerisation 
of  the  caoutchouc  occurs  during  coagulation. 

Changes  during  Development  of  Tackiness. 

The  nature  of  the  chemical  alteration  underlying  tackiness  is  yet 
a  matter  of  doubt.  Spence  will  not  admit  that  the  change  depends 
upon  oxidation  of  the  caoutchouc  hydrocarbon,  or  to  resin 
formation,  which  is  the  result  of  oxidation.  And,  of  course,  we 
can  at  once  realize  that  resin  formation  is  out  of  the  question. 

There  can  be  little  doubt  that  the  chemical  change  taking 
place  is  a  process  of  depolymerisation,  the  caoutchouc  hydrocarbon 
breaking  down  into  substances  of  the  same  percentage  chemical 
composition,  but  of  less  molecular  weight.  If  viscosity  in  solution 
is  a  test  of  the  molecular  complexity  of  a  rubber,  it  is  significant 
that  tacky  rubbers  have  a  low  viscosity. 

There  is  doubt  as  to  how  far  the  change  is  chemical  and  how 
far  physical.  Spence  remarks  that  he  is  driven  to  the  conclusion 
that  tackiness  is  not  directly  caused  by  chemical  changes  in  the 
rubber,  and  he  would  even  go  to  the  length  of  suggesting  that  it 
is  largely  the  result  of  physical  deterioration.  One  feels  that 
Spence  would  have  been  nearer  the  mark  had  he  suggested  that 
this  physical  deterioration  is  the  natural  result  of  a  chemical 
change. 

,    Testing  of  Plantation  Rubbers. 

The  desirabiUty  of  the  planter  knowing  the  defects  of  his 
rubber  is  undoubted,  but  at  present  this  knowledge  is  to  a  large 
extent  denied  him  except  in  a  very  superficial  form  ;  some  system 
of  testing  the  rubber  upon  the  spot  is,  nevertheless,  called  for.  If 
the  testing  of  rubber  is  left  to  the  buyer,  it  is  most  unhkely  that  he 
will  let  the  seller  or  producer  know  why  and  when  he  considers 
certain  samples  depart  from  the  normal.  It  is  his  duty  to  bid 
a  price  and  be  sure  he  gets  good  value  for  his  money.  How,  then, 
is  the  planter  to  know  the  real  quality  of  his  rubber  ?  Obviously 
either  he  or  his  broker  must  determine  this.  Whenever  possible, 
the  application  of  simple  and  reliable  tests,  by  the  manager's 
scientific  staff,  to  all  rubber  before  it  leaves  the  plantation  should 
be  made.  It  is  perhaps  not  too  much  to  hope  that,  seeing  many 
directors  have  had  the  good  sense  and  foresight  to  appoint  scientific 
officers  to  deal  with  pests  as  they  arise,  and  investigate  chemical 
problems  relating  to  the  soil  and  preparation  of  rubber  from  latex, 
they  will  some  day  consider  it  a  part  of  the  scientific  officers' 
duty  to  test,  and  grade  accordingly,  the  various  lots  of  rubber 
before  they  are  shipped. 

How  this  is  to  be  performed  is  as  yet  not  at  all  clear,  but  no 
doubt  in  the  course  of  time  a  series  of  simple  tests  will  be  formulated 
and  the  necessary  apparatus  devised  to  meet  the  needs  of  the 
planter.     One  source  of  difficulty  is  the  form — crepe — ^in  which 


PARA     RUBBER  449 

so  much  rubber  is  now  turned  out,  a  form  that  is  beyond  sub* 
mission  to  tensile  tests  ;  even  tests  made  on  biscuit  and  sheet  are 
not  too  rehable,  as  a  uniform  thickness  and  homogenity  of  material 
throughout  a  test-piece  cannot  be  guaranteed.  It  must  also  be 
borne  in  mind  that  in  the  preparation  of  each  kind  of  plantation 
rubber  different  physical  forces  have  been  brought  into  play 
which  have  an  effect  on  the  properties  of  the  finished  raw 
material. 

The  Force  of  Thumb. 

Unfortunately,  the  testing  of  rubber  by  some  brokers  but 
fortunately  not'  all — consists  in  smelling  at  it,  and  seeing  if  it 
will  tear  when  stretched  between  two  hands,  or  give  way  to  a 
strong  push  of  the  finger  or  thumb.  This  is  a  most  empirical 
system  of  testing,  and  yet  it  is  the  most  that  the  majority  of  con- 
signments are  submitted  to  before  being  sent  to  the  buyers.  It  is, 
indeed,  a  test  by  "  force  of  thumb." 

Consider,  for  a  moment,  what  is  done  with  tea— a  product 
which  is  shipped  in  millions  of  pounds  every  year,  from  Ceylon, 
India,  Java,  and  China.  Every  consignment  of  tea,  even  if  it 
comes  from  an  estate  which  has,  by  its  mark,  been  favourably 
known  for  twenty  years  to  brokers  and  buyers,  and  even  though  it 
may  have  been  tested  in  the  factory  before  leaving  the  plantation, 
or  in  Colombo  or  Batavia  before  being  shipped,  is  carefully  sampled 
and  a  pot  of  tea  brewed  from  it.  The ' '  tea  taster ' '  knows  the  value 
of  every  degree  of  strength  and  flavour,  and  values  the  tea  to  a 
fraction  of  a  halfpenny. 

It  is  not  suggested  that  brokers  shall  have  every  sample  of 
rubber  submitted  to  a  detailed  chemical  analysis,  or  tested  for  its 
distensibility,  durability,  breaking  strain,  etc.  ;  all  that  is  asked 
is  that  they  devise  some  simple  scheme  whereby  samples  of  even 
appearance  shall  be  tested  rapidly,  accurately  and  cheaply.  When 
one  considers  the  variability  of  plantation  lots  which  sell  at 
practically  the  same  price  per  lb.  at  the  regular  auctions  he  cannot 
help  thinking  that  someone  is  the  loser.  It  may  not  appear  very 
necessary  to  adopt  reliable  tests  to-day,  while  Hevea  rubber  sells 
at  such  high  prices,  but  when  the  price  realised  is  a  question  of  pence 
only-^and  that  is  the  difference  between  cost  of  production  and 
profit — some  radical  change  will  have  to  be  effected.  If  brokers 
and  planters  will  only  reflect  on  the  history  of  tea,  coffee,  and  other 
products,  they  will  conclude  that  the  present  system,  which  is 
literally  one  of  ' '  force  of  thumb, ' '  is  most  inadequate. 

A  scientific  system  of  testing  is  likely  to  make  itself  more 
necessary  in  future  years,  when,  in  order  to  satisfy  manufacturers 
that  there  is  the  minimum  variability,  plantation  rubbers  will  be 
more  finely  graded  than  they  are  to-day.  The  sooner  it  is 
realized  that  stretching  between  the  hands  can  never  give  an 
indication  of  the  comparative  value  of  crepe  and  sheet  from  the 
same  countrj'  the  better.  Chemical  analyses  would,  if  planta- 
tion rubbers  showed  considerable  loss  on  washing,  be  of  some  use, 

cc 


450  PARA     RUBBER 

but  under  the  circumstances  they  would  not  help  sellers  very 
much.     Some  simple  physical  device  is  wanted. 

Possible  Tests  on  the  Plantation. 

It  has  been  said  that  tests  on  raw  rubber  are  not  so  valuable 
as  those  on  the  vulcanized  article  ;  while  this  may  be  true  it  does 
not  warrant  the  setting-aside  of  all  tests  on  the  raw  plantation 
material.  Furthermore,  it  does  not  mean  that  tests  on  the 
vulcanized  article  must  always  be  made  outside  the  plantation. 
Tests  on  the  raw  and  vulcanized  article  can  be  made  on  the  planta- 
tion providing  the  staff  has  the  necessary  training  and  equipment. 
On  the  majority  of  estates,  owing  to  the  absence  of  scientific 
of&cers  and  apparatus,  tests  can  only,  at  present,  be  apphed  to  the 
rubber  prior  to  vulcanization.  The  tests  thus  apphcable  are  very 
few  in  number. 

Viscosity  appears  to  be  a  practical  test  requiring  very  Uttle 
apparatus.  Adhesion  tests,  similar  to  those  applied  in  proofing, 
may  also  be  tried.  In  this  test  the  quality  of  rubber  solution  is 
determined  by  brushing  it  on  a  piece  of  cloth  or  strong  paper  and 
allowing  it  to  dry.  The  dry  sheet  is  folded  and  the  two  surfaces 
pressed  together  and  made  to  adhere  ;  a  test  is  then  made  to 
determine  what  weight  or  force  is  required  to  tear  the  adhering 
surfaces  apart.  Simple  tensile  tests  may  also  be  applied  to  rubber 
which  has  been  pressed  into  a  definite  shape  during  cooling  or 
drying,  time  being  allowed  for  the  recovery  of  the  natural  properties 
before  the  tests  are  applied. 

Some  authorities  (Rubber  Exhibition,  191 1)  have  concluded 
that  tests  on  raw  rubber,  whether  adhesion  tests  or  viscosity  deter- 
minations, lead  to  conclusions  which  a  e  not  in  strict  correlation 
with  the  vulcanization  tests.  The  difficulties  in  carrying  out  the 
above  tests  lie  mainly  in  the  length  of  time  required  to  make 
reliable  solutions  and  the  effect  of  mastication  on  crepe  and  block 
forms. 

Tests  on  the  vulcanized  material,  which  are  eminently 
desirable,  can  be  made  in  many  ways,  some  of  which  are  indicated 
in  the  following  pages.  The  vulcanization  test  is  said  to  be 
quite  possible  on  the  plantation  (Conference,  Rubber  Exhibition, 
1911).  A  small  mixing  mill,  a  calender,  and  a  little  vulcanizing 
press,  would  not  cost  much  more  than  one  assistant's  annual 
salary.  Esch  has  suggested  that  small  pieces  of  crepe  could  be 
placed  in  a  bath  of  molten  sulphur,  heated  for  some  time,  and  on 
cooling,  be  tested  by  a  small  apparatus  similar  to  a  spring  balance. 

Another  simple  test,  likely  to  give  immediate  and  beneficial 
results,  is  that  of  testing  the  rubber  for  the  quantity  of  acid  left 
behind  after  coagulation.  The  acid  should,  if  possible,  be  entirely 
removed  by  washing.  If  some  of  the  rubber  from  the  washing 
machine  is  cut  into  small  pieces  and  boiled  for  a  few  minutes  in 
distilled  water  until  the  liquid  is  sufficiently  concentrated,  the 
application  of  litmus  paper  to  the  mixture  will  immediately  indicate 
whether  or  not  too  much  acid  has  been  left  in  the  rubber. 


PARA     RUBBER.  451 

A  great  deal  can  also  be  done  by  the  planter  if  typical  samples 
out  of  each  consignment  are  kept  in  the  factory  together  with 
details  of  preparation  and  appearance  when  packed  ;  a  comparison 
of  prices  realized  and  samples  despatched  will  soon  enable  the 
planter  to  determine  the  preparation  most  suitable  to  the  buyers. 

The  Devising  of  Reliable  Tests. 

While  the  foregoing  simple  tests  have  been  suggested  for  use  by 
the  planter,  it  must  be  admitted  that  the  whole  system  of 
testing  rubber  scientifically — crude  or  manufactured— is  now  in 
the  melting  pot.  This  is  the  case  not  only  because  great  improve- 
ments are  being  made  in  physical,  chemical,  and  mechanical 
methods,  but  also  because  the  whole  subject  is  under  the  discussion 
of  specially-constituted  committees.  There  is  a  strong  feeling 
that  improvements  in  systems  of  analysis  are  necessary  and  that 
some  standard  system  for  all  countries  should  be  adopted  so  as  to 
facilitate  business  transactions.  At  the  Rubber  Exhibition  of 
1908  an  international  committee,  with  sections  for  each  country 
participating,  was  formed.  A  general  conference  of  the  members 
of  the  committee  was  held  at  the  1911  Exhibition,  when  sectional 
reports  were  given,  and  a  scheme  for  discussion  drawn  up. 
Apparently  partly  as  a  result  of  the  formation  of  the  committee, 
the  German  and  Dutch  Governments  have  established  organiza- 
tions of  a  tentative  character.  But  we  are  not  yet  in  possession 
of  an  organized  system  of  testing  that  has  the  confidence  of 
planters,  brokers,  and  manufacturers  alike,  and  that  can  ba 
adopted  so  as  to  render  disputes  next  to  impossible. 

Chemical  Analysis  of  Crude  Rubber. 

Though  the  methods  of  chemical  analysis  do  not  always  show 
how  a  rubber  is  going  to  vulcanize  and  do  not  come  within  the 
purview  of  this  work,  some  brief  indication  may  be  given  of  their 
nature.  The  moisture  is  determined  by  the  difference  in  weight 
after  drying.  Resins  are  generally  extracted  with  acetone  and 
weighed.  The  ash  is  obtained  by  decomposing  the  rubber  under 
heat.  The  proteins  are  calculated  from  the  nitrogen  content, 
multiplying  the  value  of  the  latter  by  the  factor  6-25,  though  this 
is  open  to  objection,  as  all  the  nitrogenous  bodies  present  are  not 
proteins.  A  separate  determination  may  be  made  of  the  matter 
insoluble  in  benzene  or  other  solvent,  and  though  this  may  contain 
proteins,  there  are  other  substances  present.  Caoutchouc  is 
usually  estimated  by  difference,  a  most  unsatisfactory  method. 
Some  chemists  prefer  estimating  the  caoutchouc  by  determining 
the  amount  passing  into  solution,  and  see  no  advantage,  except 
in  special  cases,  in  those  direct  methods  of  determining  the 
caoutchouc  such  as  by  the  nitrosite  or  tetrabromide. 

Mechanical    Tests. 
Mechanical  tests  must,  according  to  some  chemists,  be  placed 
first    in    importance.     If    they    indicate    unsatisfactory    quality. 


452  PARA     RUBBER 

chemical  tests  may  then  be  applied  to  ascertain  why  this  is  the 
case.  Of  recent  years  there  have  been  great  advances  in  the 
mechanical  methods  of  testing  ;  new  principles  have  been  adopted 
and  new  apparatus  devised.  Perhaps  it  is  not  too  much  to  claim 
that  the  rise  of  the  plantation  industry  helped  to  stimulate  these 
advances,  for  the  desire  to  obtain  accurate  estimates  of  the  quality 
of  plantation  rubber  and  to  compare  it  with  that  of  fine  hard 
Para  has  been  very  great  and  has  kept  the  subject  to  the  front. 

Of  course,  not  all  the  possible  tests  are  necessary  in  every  case. 
When  being  examined  from  the  manufacturer's  point  of  view, 
the  nature  of  the  tests  vary  according  to  the  intended  use  of  the 
rubber.  And  where  rubber  is  being  used  mainly  because  of  its  non- 
permeability  to  air  or  water,  or  for,  say,  its  electrical  properties, 
very  few  tests  are  necessary,  though  those  required  are  of  a  special 
character.  Otherwise  an  extensive  series  of  tests  seems  to  be  called 
for. 

The  variety  of  tests  made  upon  the  rubber  have  been  sum- 
marized thus  by  Schidrowitz.  The  oldest  and  most  favoured 
tensile  tests  are  the  determination  of  the  breaking  stress  per  unit  of 
cross-sectional  area  and  the  elongation  at  break.  But  worth 
ascertaining  also  are  the  elongation  under  a  constant  load,  and  the 
effect  of  varying  the  load  below  the  limit  of  breaking  stress.  And 
this  is  also  true  of  the  determination  of  the  load  that  may  be 
supported  at  a  fixed  elongation  over  a  certain  time  period.  Such 
tests  as  these  lay  bare  rather  the  mechanical  strength  of  the  rubber, 
and  for  the  determination  of  its  resiliency  a  different  series  is 
made. 

The  simplest  of  these  observations  on  resiliency  are  those 
made  of  the  "permanent  set,"  or  "coefficient  of  resiliency, "  and 
the  ' '  sub-permanent  set. "  The  permanent  increase  in  length, 
after  the  full  retraction  of  the  rubber  following  upon  the  withdrawal 
of  the  stress,  is  the  ' '  permanent  set. ' '  Measured  at  definite 
intervals  before  the  rubber  has  been  allowed  time  to  fully  retract, 
it  is  the  "sub-permanent  set." 

Additional  insight  into  the  quahties  of  the  rubber  is  obtained 
by  determining  the  minimum  load  producing  a  specific  sub-per- 
manent set,  and  the  effect  upon  the  sub-permanent  set  of  varying 
the  factors  of  load  and  time. 

If  the  results  of  the  tests  are  plotted  out  in  the  form  of  curves, 
their  story  may  very  easily  be  read,  and  out  of  this  graphic  method 
•of  recording  has  arisen  a  new  form  of  determination  of  mechanical 
qualities.  If  the  stress  has  been  carried  to  a  point  short  of  the 
breaking  strain,  and  the  load  is  then  gradually  removed,  it  is  found 
that  the  retraction  curve  does  not  coincide  with  the  extension 
curve — a  phenomenon  known  as  ' '  hysteresis ' ' — the  length  of  the 
rubber  under  the  same  load  being  different  during  extension  and 
retraction.  The  double  curve  thus  obtained  is  known  as  the 
hysteresis  loop, ' '  and  much  knowledge  of  the  quahty  of  the 
rubber  may  be  gained  by  a  study  of  the  form  of  the  double  curve,  of 
the  area  enclosed,  and  of  the  relationships  of  area  to  load  and 


PARA     RUBBER 


453 


elongation.  According  to  Schidrowitz,  these  are  much  more 
important  factors  in  forming  an  estimate  of  the  quality  of  rubber 
than  the  question  of  "set."  A  series  of  hysteresis  loops,  shewing 
the  effects  of  a  series  of  repeated  elongations,  is  most  instructive 
of  all. 

Beyond  the  tensile  tests,  there  are  few  in  the  mechanical  division 
which  can  be  here  described.  Rubber  for  railway  buffers  and  the 
hke  is  submitted  to  so-called  compression  tests  It  has  already 
been  said  that  rubber  is  practically  incompressible,  but  these  are 
leally  tests  of  the  capacity  of  the  rubber  to  return  to  its  original 
shape  after  distortion  by  compression.  In  abrasion  tests  the 
rubber  undergoes  continuous  friction,  as  when  placed  against  an 
emery  wheel.  Hardness  may  also  be  measured,  and  also  porosity 
to  air  and  water. 

Schwartz's  Hysteresis  Machine. 

This  machme  for  determining  hysteresis  is  designed  to  effect 
the  extension  of  the  rubber  by  a  load  which  is  increased  at  a  given 


Schwartz's  hysteresis  machine. 


rate  until  either  a  given  load  or  a  given  extension  is  reached.    Then 
the  load  is  lessened  at    the  same  rate  and  the  rubber  allowed  to 


454 


PARA     RUBBER 


retract.  An  automatic  recording  device  traces  extension  and 
retraction  curves — the  two  together  forming  the  hysteresis  loop — 
upon  a  chart  lying  on  a  travelling  table. 

The  stress  is  exercised  from  the  wheel  M,  the  axle  of 
which  is  screw-threaded  so  that  K  travels  up  and  down  and 
thereby  moves  the  floating  pulley  G.  Any  force  exercised  through 
this  pulley  is  distributed  so  that  both  the  strip  of  rubber  D  and  a 
calibrated  spring  H  are  stretched.  To  the  ends  of  each  of  these  is 
attached  a  thread,  one  (P)  attached  to  the  clip  at  the  end  of  the 
rubber,  causing  the  movement  backwards  and  forwards  of  the 
pencil  N  according  to  the  extension  of  the  rubber,  the  other  (W), 
attached  to  the  end  of  the  spring,  and  therefore  moving  according 
to  the  load,  moves  the  traveUing  table.  These  two  movements 
result  in  the  tracing  of  the  hysteresis  loop  upon  the  chart.  A 
series  of,  say,  five  hysteresis  tests  may  be  made  rapidly. 

A  study  of  the  loop  diagram  enables  one  to  determine  :  (i) 
the  degree  of  extension  with  load  ;  (2)  the  work  done  in  extension  ; 
(3)  the  work  done  by  the  rubber  in  retracting  ;  (4)  the  work 
expended  by  the  rubber  itself ;  (5)  the  sub-permanent  set. 

Breuil's   and   Schopper's   Testing    Machines. 

Breuil's  dynamometer  tests  rubber  in  strip  form  and  is  pro- 
vided with  a  variety  of  devices  for  determining  the  different 
qualities  of  rubber.  It  permits  of  making  slow,  rapid,  or  inter- 
mittent  tensile   tests  ;   slow,   rapid   or  intermittent   compression 


BREUIL  S    DYNAMOMETER. 


tests  ;  repeated  flexion  (bending)  tests  ;  and  tests  of  wear  and 
resistance  to  perforation.  An  automatic  device  registers  the 
results  automatically  in  diagrammatic  form. 

In  the  Schopper  apparatus  a  ring  punched  out  of  a  sheet  of 
the  material  is  tested  for  elongation  at  break  and  breaking  strain. 


PARA     RUBBER 


455 


The  ring  is  stretched  between  two  rotating  spools,  so  that  every 
part  of  it  is  submitted  in  turn  to  the  stress.  The  machine  is 
worked  by  hydrauUc  power,   a  gravitation  water  supply  giving 


schopper's  testing  machine. 


40  lb.  pressure  being  sufficient.  This  machine  also  is  provided 
with  an  automatic  recording  device,  and  may  be  worked  at  various 
speeds. 


456  PARA     RUBBER 

Viscosity  Tests. 

A  new  method  of  estimating  the  quahty  of  rubber  is  the 
determination  of  the  viscosity  of  a  solution.  It  has  always  been 
recognised  that  low-grade  highly-resinous  rubbers  tend  to  give 
thin  solutions,  and  high-grade  rubbers  highly-viscous  ones. 
Schidrowitz  and  Goldsborough  advance  the  theory  that  the 
degree  of  viscosity  approximates  fairly  closely  to  the  nerve  of 
the  rubber.  The  theory  is  based  upon  the  hypothesis  that  the 
nerve  of  a  piece  of  rubber  depends  upon  the  molecular  com- 
plexity of  its  contained  caoutchouc,  and  that  viscosity  is  a  function 
of  molecular  complexity.  Schidrowitz  claims  that  with  rubber 
from  the  same  species  of  tree,  viscosity  measurements  give  a 
direct  Hue  as  to  strength  and  vulcanizing  capacity.  The  method 
is  obviously  pecuharly  adapted  for  testing  rubbers  before  vulcaniza- 
tion. 

An  improved  apparatus  for  making  the  determination  has  been 
devised  by  Frank  (I.R.J.,  April,  1910).  I  am  under  the  impression 
that  this  apparatus,  while  giving  comparative  commercial  figures 
representing  ' '  fluidity ' '  of  commercial  solutions,  does  not  give 
results  of  the  same  order  as  viscosity  tests  made  in  a  viscometer  of 
the  scientific  type.  The  results  only  refer  to  the  properties  of 
solutions  of  a  given  concentration  and  not  to  the  viscosity  of  the 
rubber  as  such. 

In  their  work  upon  rubber  (p.  100),  Beadle  and  Stevens  remark 
that  mastication  of  rubber  has  an  effect  upon  the  readiness  with 
which  it  dissolves  and  on  the  viscosity  of  solutions,  so  that  biscuits 
and  sheets  are  less  easily  soluble  than  crepe.  Thus  viscosity  tests, 
according  to  them,  may  be  vitiated  by  the  presence  of  the  finely- 
divided  (solid)  protein  matter  which  results  from  mastication  or 
is  present  in  the  crude  rubber.  This  objection  cannot,  pre- 
sumably, apply  to  efficiently  filtered  solutions. 

Physical  Tests. 

According  to  the  purpose  for  which  the  rubber  is  intended  to 
be  used,  various  physical  tests,  i.e.,  determinations  of  its  behaviour 
under  the  action  of  physical  agents — heat,  etc. — may  be  made,  but 
always  upon  vulcanized  samples.  The  British  Admiralty  require 
that  rubber — intended  for  valve-packings,  etc. — shall  be  subjected 
to  dry  and  moist  heat  tests.  In  the  former  the  sample  is  kept  in  a 
hot-air  oven  for  two  hours  at  a  temperature  of  132°  C,  and 
deterioration  is  noted  or  mechanical  tests  made  before  and  after 
the  application  of  heat.  In  the  latter  it  is  heated  in  steam  in  a 
sealed  glass  tube  or  an  autoclave  for  3  or  4  hours  at  160°  C.  If  the 
rubber  is  intended  for  insulating  purposes,  appropriate  tests  are 
made.  The  usual  "sun  cracking"  tests  are  also  applied  in  certain 
cases. 

Chemical  Tests. 

Sometimes  it  is  necessary  that  the  behaviour  of  rubber  in 
acids,  alkalies,  oils,  etc.,  should  be  noted.     Such  observations  are 


PARA     RUBBER  457 

made  upon  samples  prepared  in  exactly  the  same  manner  and  of  the 
same  composition  as  the  manufactured  article.,  for  the  compounding 
ingredients  modify  the  behaviour  of  the  rubber,  either  in  an 
indirect  way  or  by  themselves  being  affected. 

I  have  gone  into  some  little  detail  on  the  subject  of  testing 
in  the  hope  that  many  producers  in  the  tropics  will  find  information 
which  will  lead  them  to  evolve  or  suggest  tests  of  some  use  to 
themselves  in  future  years.  At  a  later  date  reference  must  be 
made  to  scientific  apparatus  described  in  other  books  and  in  the 
various  journals  devoted  to  rubber. 


CHAPTER    XXIX. 

MANUFACTURE     AND     COMPOSITION     OF 
RUBBER     ARTICLES. 

Rubber,  as  shipped  from  the  plantations,  differs  very  little 
from  that  received  in  the  factory  of  the  manufacturer.  It  may 
have  lost  from  half  to  one  per  cent,  in  weight  through  the  evapora- 
tion of  water,  or  have  become  hard  in  winter  months.  On  its 
arrival  at  London,  Liverpool,  Antwerp,  or  New  York,  it  is  stored 
in  vaults  at  the  wharves,  where  every  care  is  taken  to  protect 
the  rubber  against  exposure  to  sunUght  and  foul  air.  Only  samples 
are  removed  from  the  wharves  prior  to  the  auctions  at  the  sale- 
rooms. 

Masticating   and   Mixing. 

The  first  processes  through  which  ordinary  wild  rubber  is 
put  are  washing  and  drying  ;  with  the  plantation  product  these 
can  sometimes  be  almost  entirely  dispensed  with.  The  dry,  clean 
rubber  is  then  put  through  the  masticating  machines. 

This  is  done  in  order  to  convert  it  into  a  soft,  doughy  mass,  and 
is  achieved  by  passing  the  dry  rubber  through  a  pair  of  smooth 
rollers  heated  by  means  of  steam  similar  to  those  on  a  sheeting 
washing  machine.  In  the  course  of  half-an-hour  the  rubber  is 
usually  of  the  required  consistency  for  the  next  process — mixing — 
to  be  put  in  operation. 

In  mixing,  the  various  compounding  ingredients,  having  been 
carefully  weighed,  are  placed  on  the  rubber,  and  by  repeatedly 
passing  through  the  rollers  of  the  masticating  machine  are  uniformly 
distributed  and  worked  into  it.  The  masticating  and  mixing 
processes  can  be  carried  out  on  the  same  machine,  though  it  is 
usual  to  keep  separate  machines  for  each  process. 

Calenderin'g. 

What  happens  next  depends  upon  the  kind  of  goods  to  be 
manufactured.  Generally  the  compounded  rubber  is  passed 
through  a  calender,  and  is  thereby  turned  out  in  the  form  of 
sheet,  which  is  led  to  a  revolving  wooden  roll  on  which  it  is  layered 
or  rolled  between  cloth.  A  calender  consists  essentially  of  super- 
imposed smooth  rollers,  two  or  more  in  number,  between  which  the 
rubber  can  be  fed.     The  rollers  are  hollow  for  steam-heating. 

If  the  rubber  is  not  intended  to  be  prepared  in  sheet  form,  the 
material  from  the  mixing  rollers  may  be  pressed  into  moulds,  or 
forced  through  a  die,  as  when  solid  tyres  and  some  forms  of  tubing 
are  being  made. 


Lent  hy  Jas.  SoUnson  &  Co. 
THREE-ROLL      CALENDER       WITH      MOTOR. 


Lent  hy  Jas.  Rdbivson  <i  Co. 
MIXING       MILL. 


^?!r''??'«^V>;m 


L™(  hy  Jas.  nohinsmt  <C'  Co. 
HYDRAULIC      VULCANIZING      PRESS. 


PARA     RUBBER  459 

If  the  article  to  be  prepared  is  elastic  thread  the  washed  crude 
rubber  is  spread  on  cloth  and  vulcanized  by  the  cold  method. 

Vulcanization. 

Vulcanization  is  effected  by  mixing  sulphur  in  one  of  its 
many  forms  with  the  masticated  rubber  and  then  heating  the 
mixture,  or  by  dipping  the  manufactured  article  in  a  liquid  con- 
taining monochloride  of  sulphur  and  bisulphide  of  carbon.  Usually 
only  from  4  to  5  per  cent,  of  sulphur  is  used  in  ordinary  vulcaniza- 
tion, but  in  the  production  of  ebonite  or  vulcanite  as  much  as  20  to 
40  per  cent,  of  sulphur  may  be  used.  A  more  complete  distribution 
of  sulphur  through  the  rubber  may  be  possible  if  a  solution  con- 
taining sulphur  be  added  to  the  latex  before  coagulation.  Prismatic 
sulphur  is  readily  soluble  in  carbon  bisulphide,  benzene,  ether,  &c.  ; 
solutions  may  be  made  with  any  of  these  and  other  reagents  con- 
taining varying  amounts  of  sulphur. 

In  vulcanization  most  of  the  sulphur  becomes  fixed  by  the 
rubber,  but  not  the  whole  of  it ;  there  is  always  a  certain  quantity 
of  sulphur  in  a  free  state  in  vulcanized  articles.  Ordinary  sulphur, 
or  various  compounds  of  sulphur,  may  be  used  in  this  process. 

The  Heat  and  Cold  Cures. 

In  the  ' '  heat  cure ' '  the  rubber  and  sulphur  are  brought  into 
intimate  admixture  by  masticating  and  mixing,  or  the  rubber 
is  dissolved  in  naphtha  to  facilitate  the  mixing  with  sulphur. 
The  temperature  is  then  raised  to  over  100°  C,  when  chemical 
union  takes  place  between  the  components,  and  vulcanized  rubber 
is  formed.  The  whole  of  the  sulphur  does  not  combine  with 
the  rubber,  but  if  the  high  temperature  is  maintained  for  a  long 
period,  more  and  more  of  the  free  sulphur  enters  into  combination 
and  produces  a  darker  and  tougher  vulcanized  product.  Action 
does  not  begin  between  the  two  constituents  until  the  temperature 
is  equal  to  or  above  that  of  boiling  water  ;-  in  Europe  a  temperature 
varying  from  125°  to  over  300°  C.  is  commonly  used  in  the  process 
of  vulcanization.  ^  If  alkaline  polysulphides  are  used,  vulcanization 
can  be  effected  at  temperatures  little  above  100°  C.  The  essential 
detail  in  the  "heat  cure"  method  is  that  the  temperature  of 
vulcanization  must  be  above  the  melting-point  of  sulphur — 
114-5°  C. 

Though  most  of  the  rubber  is  vulcanized  by  the  above  process, 
the  ' '  cold  cure,"  dependent  upon  the  action  of  sulphur  components 
in  the  cold,  is  often  adopted.  In  the  ' '  cold  cure, ' '  diluted  sulphur 
monochloride  is  mixed  with  the  rubber,  with  which  it  readily 
combines  at  ordinary  temperatures,  and  produces  a  vulcanized 
product  suitable  for  the  manufacture  of  goods  which  would  be 
damaged  by  high  temperatures.  Sulphur  monochloride  is  a  liquid 
at  ordinary  temperatures,and  on  account  of  its  violent  action  with 
rubber  is:  diluted  by  dissolving  in  carbon  bisulphide  before  being 
used  for  vulcanizing.  The  sulphur  chloride,  with  the  help  of  the 
solvent,  penetrates  into  the  rubber. 


46o  PARA     RUBBER 

Apparatus  used  ix  Vulcanization. 

Vulcanization  is  usually  effected  in  long  cylindrical  boilers 
or  presses.  The  boilers  or  pans  are  heated  by  steam,  which 
is  well  distributed  in  order  to  effect  uniform  heating.  The  goods 
are  run  into  the  cylinder  or  wheeled  cages  along  hght  rails,  the 
door  is  then  bolted,  and  the  process  commenced. 

Vulcanizing  presses,  which  serve  as  heaters  and  moulds, 
may  also  be  used.  They  consist  of  series  of  steam  boxes,  each 
provided  with  smooth  even  surfaces  facing  one  ariucher,  and 
capable  of  being  worked  by  hydraulic  pressure. 

Using   Latex   Directly. 

j\lany  attempts  have  been  made  to  use  latex  direct,  or  after 
treatment  with  sulphur  solution,  in  the  preparation  of  rubber 
articles.  Large  quantities  of  latex  have  been  sent  to  Europe  from 
Africa,  Brazil  and  the  Indo-Malayan  region,  and  though  it  appears 
to  have  arrived  in  a  satisfactory  state,  but  Httle  advance  has  been 
made  in  this  line  of  research.  Hancock  (LR.J.,  Oct.  8th,  1906), 
so  far  back  as  1825  patented  a  process  for  the  manufacture  of 
certain  ropes  by  treating  the  surface  of  the  fibres  with  latex  which, 
on  coagulation,  formed  a  waterproof,  elastic,  and  durable  covering  ; 
at  a  later  date  he  also  invented  a  process  of  mixing  the  latex  with 
a  fibrous  compound  made  by  mixing  hair,  wool,  cotton,  etc.,  to 
which  certain  substances,  such  as  whiting,  ochre,  brickdust, 
emery  powder,  were  added  according  to  requirements.  As  the 
result  of  his  labours,  Hancock  finally  decided  not  to  make  any 
further  efforts  in  connection  with  the  utilization  of  latex  direct, 
mainly  owing  to  the  difficulties  he  experienced  in  obtaining  it  in 
sufficiently  large  quantities  and  in  good  condition.  In  his  summing 
up  he  states  that  ;  ' '  Although  rubber  in  this  state  would  be  very 
useful,  and  many  things  could  be  done  with  it  which  are  hardly 
practicable  with  the  solutions,  yet  the  loss  of  weight  by  evaporation 
being  nearly  two-thirds  of  the  whole,  the  expense  of  vessels  and  the 
freight  of  so  much  worthless  matter  will  probably  prevent  its  ever 
being  used  extensively.  Before  the  difficultv  of  dissolving  ordinary 
rubber  was  overcome,  it  was  thought  that  the  liquid,  if  it  could  be 
obtained,  would  be  invaluable  ;  but  now,  all  things  considered,  the 
dry  material,  for  nearly  all  the  purposes  of  manufacture,  is  the 
cheapest  and  most  easily  applied,  although  to  persons  unacquainted 
with  practical  details  this  may  appear  enigmatical." 

Bamber  subsequently,  in  a  somewhat  similar  manner,  made 
samples  of  rubber  belting,  flooring,  mats,  etc.,  by  using  sulphurized 
latex  in  conjunction  with  waste  coir-dust  and  coconut  fibre. 
When  these  are  thoroughly  mixed  and  combined  with  sulphur, 
and  the  mass  is  dried  and  vulcanized,  a  strong,  hard,  and  pliable 
article  is  said  to  be  obtained. 

A  method  of  rendering  garments  waterproof  by  the  direct 
use  of  latex  has  been  experimented  with  by  Henri.  The  cloth 
is  first  placed  in  warm  water,  and  is  then  dipped  in  the  latex 


PARA     RUBBER  461 

several  times,   when   the  fibre  of  the  cloth  becomes  thoroughly 
penetrated.     Vulcanization  follows. 

Colouring  Latex. 

The  latex  can  also  be  coloured  by  organic  dyes  (T.A.,  Oct., 
1906),  such  as  methylene  blue,  etc.,  and  any  poisonous  colouring 
matter  be  thoroughly  mixed  with  the  rubber  instead  of  being  put 
on  the  outside  as  is  so  often  done  in  the  manufacture  of  children's 
toys.  It  is  interesting  to  note  that  though  Hancock  pointed  this 
principle  out  in  1857,  the  method  has  not  been  taken  up  on  com- 
mercial lines  in  any  of  the  countries  where  rubber  plants  are 
cultivated.  Among  the  more  notable  colouring  substances  used 
by  rubber  manufacturers  are  vermilion,  lithopone,  golden  sulphide, 
red  and  brown  oxides,  zinc  white  and  others,  many  of  which  contain 
combined  sulphur. 

Sulphurizing  Latex. 

The  subject  of  the  treatment  of  the  latex  with  solutions 
which  will  precipitate  large  quantities  of  free  sulphur  in  a  fine 
state  of  division,  is  one  which  has  been  much  ventilated.  In  one 
process  (T.A.,  Oct.,  1906),  a  solution  of  sulphur  is  added  to  the  fresh 
latex  and  thoroughly  stirred.  On  treatment  with  acid,  sulphur 
is  precipitated  and  the  latex  coagulated,  the  resultant  rubber 
being  minutely  permeated  with  the  finely-divided  particles  of 
sulphur.  The  complete  mixing  of  sulphur  with  the  latex  while 
the  latter  is  in  a  liquid  condition  is  intended  to  do  away  with  this 
process  at  a  later  stage  in  the  manufacture  of  the  rubber  goods,  and 
to  thereby  effect  a  saving  in  time  and  power. 

Feasibility  of  the  Direct  Use  of  Latex. 

It  should,  however,  be  pointed  out  that  the  processes  through 
which  raw  rubber  has  to  pass  in  the  manufactories  are  not  designed 
solely  for  the  perfect  mixing  of  sulphur  with  rubber,  but  for  the 
removal  of  various  impurities — economically  impossible  once  the 
latex  has  been  sulphurized — and  the  admixture  of  various  com- 
pounding ingredients,  known  only  to  the  trade.  It  is  not  likely 
that  the  manufacturers  are  going  to  instruct  planters  what  com- 
pounding ingredients  must  be  mixed  with  the  latex  prior  to 
vulcanization. 

If  the  direct  treatment  of  the  latex  is  to  be  of  ava;il  to  European 
producers  in  the  tropics,  it  appears  to  be  necessary  to  first 
remove  undesirable  impurities  and  subsequently  add  not  only 
the  required  sulphur  but  the  balance  of  compounding  ingredients 
commonly  used.  It  is  difficult  to  see  how  the  admixture  of  sulphur 
alone  to  ordinary  latex  can  at  present  be  a  very  great  saving 
of  labour  to  manufacturers  who  deal  with  wild  and  plantation 
rubber.  It  still  leaves  the  raw  rubber  of  the  wild  forests  to  be 
dealt  with  on  old  lines,  and  prevents  the  removal  of  undesirable 
components  from  the  latex  so  sulphurized. 


462  PARA     RUBBER 

Furthermore,  the  treatment  of  latex  while  in  a  Uquid  condi- 
tion necessitates  the  introduction  of  various  arrangements  not  at 
present  in  common  practice.  It  is  necessary  in  the  first  case  to 
keep  the  latex  in  a  liquid  condition  from  the  moment  it  leaves 
the  tree  to  its  arrival  at  some  central  factory,  and  to  so  treat  the 
latex  that  it  will  not  deteriorate  during  transit.  Experience  has 
taught  most  people  that  the  whole  of  the  latex  cannot  be  collected 
as  such,  a  large  proportion  invariably  drying  up  as  scrap 
especially  with  latex  other  than  that  from  Hevea  hrasiliensis. 
It  is  also  maintained  that  the  addition  of  ammonia  and  formalin — 
especially  the  former — is  not  always  accompanied  with  constant 
results,  and  the  latex,  owing  to  its  very  varied  composition,  is 
difficult  to  standardize. 

Sulphurizing  Freshly-Coagulated  Rubber. 

When  the  coagulation  of  the  latex  is  complete,  the  rubber  is  in 
a  very  soft  spongy  state  and  can  be  easily  torn  into  very  small 
pieces,  kneaded,  and  rolled  or  pressed  into  any  desired  shape. 
On  some  estates  experiments  have  been  made  with  the  freshly- 
coagulated  rubber  while  in  this  condition,  mixtures  of  sulphur 
with  other  ingredients  being  added,  and  after  thorough  mixing, 
pressed  into  blocks  or  sheets  and  dried  It  is  obvious  that  rubber 
so  treated  possesses  the  maximum  amount  of  resinous,  protein 
and  other  impurities,  and  if  washed  after  the  additional  com- 
pounding ingredients  have  been  mixed  with  it,  a  loss  of  the  latter 
may  be  occasioned. 

The  mixing  of  foreign  ingredients  with  rubber,  if  ever  con- 
sidered desirable,  can,  as  far  as  ordinary  estates  are  concerned, 
be  best  carried  out  when  the  rubber  is  in  the  freshly-coagulated 
spongy  state.  To  adopt  such  a  treatment,  on  the  plantation,  with 
the  rubber  after  it  has  passed  through  the  washing  machine  would 
not  be  attended  with  satisfactory  results ;  the  processes  of  masti- 
cating and  mixing  can  be  best  performed  by  the  manufacturer. 

It  has  been  claimed  that  the  addition  of  these  ingredients 
prevents  the  rubber  from  becoming  soft  or  tacky,  and  that  there  is 
an  improvement  in  the  physical  properties  of  the  rubber.  The 
tackiness  or  softening  may,  however,  be  obviated  by  careful  work 
during  drying  and  washing  or  the  addition  of  suitable  antiseptics  to 
the  latex.  Except  it  is  desired  to  conduct  the  manufacturing 
operations  in  the  tropics,  there  appears  to  be  very  little  in  favour 
of  adding  a  small  percentage  of  certain  vulcanizing  and  com- 
pounding ingredients  to  the  freshly-coagulated  rubber.  The 
writer  certainly  does  not  know  of  any  manufacturers  who  have 
asked  for  rubber  in  that  condition. 

Henri  claimed  to  have  devised  a  method  by  which  the  rubber 
in  latex  could  be  obtained  in  the  form  of  a  cream  as  thick  as  one 
wishes.  One  is  able  to  mix  with  it  in  this  state  sulphur  and  other 
compounds,  obtaining  homogeneous  mixtures  thereby.  Such  a 
cream,  as  he  pointed  out,  can  easily  be  treated  in  manufacture.  As 
Henri  made  his  claim  in  1907,  and  has  been  silent  on  this  subject 


PARA     RUBBER  463 

since,  the  method  has  apparently  not  been  brought  to  a  successful 
issue. 


Compounding  of  Rubber:    Ingredients  Used. 

When  crude  rubber  increases  in  price,  there  is  a  tendency 
towards  the  loading  of  rubber  goods  with  higher  percentages  of 
compounding  ingredients,  as  well  as  of  substitutes  and  inferior 
rubber.  It  must,  however,^  be  made  clear  that  compounding 
ingredients,  used  in  reason,  confer  some  benefit  and  are  essential 
in  most  classes  of  goods.  Further,  to  use  high-class  rubber  would 
in  very  many  cases  be  wasteful. 

Thus  it  is  sometimes  economical  to  use  compounding  ingredi- 
ents simply  as  fillers.  They  may  also  be  used  to  colour  the  rubber. 
But  more  important  purposes  to  which  they  may  be  applied  are  the 
making  of  rubber  tougher,  harder,  or  more  resilient,  the  rendering 
of  it  more  resistant  to  the  action  of  oils,  acids,  and  other  chemicals, 
and  the  increasing  of  its  heat-resisting  and  electrical-insulating 
capacity,  or  the  decreasing  of  its  permeability  to  water.  One 
very  convenient  advantage  with  certain  compounds  is  that  they 
contain  the  sulphur  necessary  in  vulcanization  ;  a  further  advantage 
is  that  some  may  accelerate  vulcanization.  For  some  or  other  of 
these  purposes  are  used  :  magnesia,  litharge,  red  sulphide  of 
antimony,  zinc  oxide  and  sulphide  and  carbonate,  plumbago, 
white  lead,  red  oxide  of  iron,  barytes,  French  chalk,  whiting,  lamp- 
black, asbestos  powder,  infusorial  earth,  etc.,  etc.  The  value  and 
even  necessity  of  many  compounding  ingredients  is  not  realized 
by  every  consumer  of  rubber. 

Quantity  of    Rubber  in  Common  Articles. 

The  important  part  which  rubber  and  sulphur,  together 
with  other  substances,  play  in  the  manufacture  of  articles  in 
common  use,  is  little  less  than  remarkable. 

The  following  analyses  are  given  by  Weber  : — 

Outer 
Roller        Steam      Cover     Tobacco  Garden 
Covering.  Packing,  of  a  Tyre.  Pouch.    Hose. 


Rubber 

% 
•     24-49 

% 

12-73 

0/ 
/o 

54-70 

0/ 
/o 
50-22 

0/ 
/o 

31-29 

Free  sulphur 

1-23 

.2-IO 

0-88 

0-27 

1-83 

Sulphur  of  vulcanization 

0-84 



1-99 

2-72 

2-15 

Mineral  matter 

■      72-33 

62-81 

41-08 

2-19 

26-28 

Organic  extract 

I'lO 

2-82 

1-34 

4-88 

7-34 

Carbonaceous  matter 

— 

19-53 

— 

— 

— 

Fatty  substitute     . . 

— . 

— 

37-21 

28-90 

Chlorine 

— 



— 

2-50 

2-20 

The  presence  of  as  much  as  50  to  54  per  cent,  of  rubber  in  an 
ordinary  tyre  and  tobacco  pouch,  the  use  of  nearly  30  per  cent,  of 
fatty  substitutes  in  garden  hoses,  and  over  70  per  cent,  of  mineral 
matter  in  roller- covering  made  from  fine  Para,  should  be  noted. 


464  PARA     RUBBER 

Rubber  in  Tyres. 

A  considerable  amount  of  analytical  work  has  been  done  in 
Europe  with  the  object  of  determining  the  composition  of  rubber 
tyres.  Schidrowitz  and  Kaye  (Journal  Soc.  of  Chem.  Ind., 
Feb.  28th,  1907)  conducted  an  examination  of  tyre  covers  of 
representative  makes,  and  the  following  are  analyses  of  several 
brands  which  they  investigated  : — 


Mark. 

B. 

D. 

D. 

E. 

F. 

Part  of  tyre. 

Tread. 
0/ 

Tread. 
0/ 

Body. 

% 
83-76 

Tread. 

Tread. 

Rubber 

/o 

69-10 

/o 
53"07 

/o 
65-00 

/o 
30-82 

Organic  extract 

5-80 

3-13 

4' 54 

7-90 

9-50 

Sulphur;   Total 

5-80 

4-00 

4-90 

9-80 

2-78 

Mineral  matter 

19-30 

39-80 

6- 80 

17-30 

56-80 

Fatty  substitutes 

Nil. 

Nil. 

Nil. 

Nil. 

NU. 

They  concluded  that  manufacturers  are  by  no  means  agreed 
as  to  the  quantity  of  rubber  and  mineral  matter  to  be  used. 
Certainly  the  analyses  pubhshed  show  that  the  proportion  of 
rubber  is  very  variable  in  the  covers  examined. 

Clayton  Beadle  and  Stevens  (Chemical  News,  August  2nd, 
1907),  subsequently  gave  an  account  of  their  investigations  into 
the  composition  and  value  of  tyre  rubbers  :  the  following  are 
results  obtained  with  solid  tyres  : — 


Rubber  (caoutchouc)  by  difierence 
Rubber  substitutes  (alcoholic  potash  ex- 
tract) 

Resins,  &c.  (acetone  extract) 
Mineral  matter  (ash) 
Total  sulphur  (calculated  on  caoutchouc 


Sample   i.  2.  3.  4. 

%  %  %  % 

42-3  43-3  430  47-7 


IO-2  89  g-i  11-7 

9-0  8-6  7-2  7-4 

38-5  39-2  40-7  33-2 

7-8  9-0  lo-o  11-3 


Vulcanite  or  Ebonite. 

This  material  is  produced  by  using  a  much  larger  proportion 
of  sulphur  in  vulcanization  than  for  ordinary  goods,  while  the 
mixture  is  heated  for  a  much  longer  time  and  (or)  at  a  higher 
temperature.  A  plastic  mass  results  that  hardens  to  vulcanite 
on  cooling.  Yet  this  material  has  little  interest  from  the  planta- 
tion point  of  view,  for  inferior  quality  rubber  can  frequently 
be  used  in  its  preparation. 

General  Uses  of  Rubber. 

The  finished  product  forms  an  important  factor  in  every- 
day life.  In  personal  use  it  appears  as  rubber  boots  and  shoes, 
goloshes,  heels,  tobacco  pouches,  pencil  erasers,  and  umbrella 
and  other  rings.  It  takes  its  place  in  the  household  in  the  form  of 
mats,  bags,  door  stops,  sponges,  bottle  and  other  stoppers,  and 
garden  hose.  In  the  field  of  sport  it  is  used  in  game  and  fishing- 
bags,  tennis  and  golf-balls,  football-bladders,  children's  playing- 
balls  and  even  rubberized-leather  cricket  balls.  In  the  workshops 
are  rubber- valves,  packing  and  belting,  and  in  the  office  erasers  and 


PARA     RUBBER  465 

dating-stamps.  To  the  chemist,  doctor  and  electrician,  rubber- 
tubing,  storage-bottles,  and  gloves  are  indispensable.  If  one 
travels,  one  cannot  help  being  impressed  by  the  universal  oc- 
currence of  rubber.  The  streets  are  cleaned  with  rubber  strips 
fixed  on  wood.  Every  second  person  or  passing  cart  is  using 
water-proofed  goods  of  some  description  or  other.  Vehicular 
traffic  appears  to  be  absolutely  dependent  upon  rubber,  and  in 
this  direction  larger  quantities  are  being  consumed  month  by 
month.  In  th^  buffers  of  railway- carriages  it  saves  the  passengers 
many  a  jolt.  Overhead,  telegraph  and  telephone  wires,  balloons, 
and  even  aeroplanes  cannot  do  without  it.  On  the  sea  one  finds  it 
as  the  floor-tiling  of  the  corridors  and  halls  of  steamers.  Even 
below  the  surface  of  the  sea  it  may  be  found  surrounding  tele- 
graphic cables.  The  usefulness  of  rubber  articles,  the  dependence 
of  other  industries  upon  rubber,  and  the  world-wide  distribution 
of  rubber  goods  all  testify  to  the  importance  of  our  product. 

Raw   Materials    Required   by    Rubber   Manufacturers. 

In  dealing  with  the  manufacture  of  rubber  goods,  it  has  now 
been  shown  that  raw  rubber  is  not  the  only  substance  required. 
It  must  also  be  realized  that  the  life  of  a  sample  of  rubber  is  not 
limited  to  that  of  the  article  into  which  it  is  first  made.  It  has 
already  been  shown  that  various  compounding  ingredients  are 
used  in  large  quantities.  There  are  also  numerous  substitutes, 
mainly  oxidised  oils,  and  many  so-called  artificial  rubbers  required 
in  ordinary  manufacture.  Over  and  above  these  there  are  enor- 
mous quantities  of  rubber  waste  which  are  annually  reclaimed  and 
reformed.  Probably  the"  least  important,  though  none  the  less 
interesting,  source  of  raw  material  is  the  ' '  synthetic ' '  product. 

Synthetic     Rubber. 

Synthetic  rubber  may  be  defined  as  one  built  up  by  chemical 
means  from  various  substances,  and  possessing  all  the  chemical  and 
physical  properties  of. natural  rubber.  It  is  essentially  formed  of 
the  same  hydrocarbon  or  hydrocarbons  that  occur  in  natural 
rubbers.  As  a  standard  for  natural  rubber  one  may  take  that 
obtained  from  Hevea  brasiliensis. 

Now  natural  rubber  consists  chemically  of  very  complicated 
compounds,  the  most  important  of  which  are  distinguished  by  the 
terms  caoutchouc,  resins  and  proteins.  Water  and  various  mineral 
substances  also  generally  occur  in  raw  rubbers,  but  need  not  be 
specially  considered  here.  It  may  not  be  well  known  to  many,  but 
it  should,  nevertheless,  be  borne  in  mind,  tLat  some  of  the  foremost 
rubber  chemists  of  the  day  frankly  acknowledge  their  ignorance 
regarding  the  exact  chemical  constitution  of  some  of  the  substances 
which  normally  occur  in  almost  every  sample  of  natural  rubber. 

The  substances  referred  to  in  such  empirical  terms  as  "resins" 
and  '  'proteins"  are  in  themselves  highly  complex  bodies,  the  com- 
ponents of  which,  though  recognised  and  conveniently  grouped  to- 
gether, are  but  little  understood.   The  synthesis  of  caoutchouc,  the 

DD 


466  PARA     RUBBER 

essential  and  therefore  the  most  important  constituent  of  natural 
rubber,  has  received  more  attention  from  chemists  than  the  average 
person  ever  dreams  of,  and  yet  it  has  never  been  made  successfully 
on  a  commercial  scale,  except  in  small  quantities. 

History  of  Synthetic  Rubber. 

The  first  report  of  the  synthesis  of  a  rubber  hke  substance 
was  made  in  i85o  by  Williams.  Isoprene,  after  standing  for  some 
months,  had  become  viscid,  oxygen  being  absorbed.  Upon 
distillation  of  the  product,  the  oxygen  was  given  up,  and  a  white, 
spongy,  elastic  mass  remained  which  gave  the  same  odour  as 
caoutchouc  when  burnt.  In  1879,  treating  isoprene  with  strong 
acids,  such  as  hydrochloric,  Bouchardet  obtained  a  tough,  elastic 
solid  that  he  and  Tilden  found  to  be  apparently  a  true  rubber. 
Wallach  later  reported  the  polymerisation  of  isoprene  that  had 
been  exposed  to  light  for  a  long  time,  from  which  a  caoutchouc- 
like mass  separated  out  upon  the  addition  of  alcohol.  In  1892 
Tilden  found  masses  floating  in  isoprene  that  had  been  stored 
in  bottles  for  several  years  ;  these  masses  possessed  the  physical 
and  chemical  properties  of  caoutchouc  and  united  with  sulphur  to 
form  a  tough,  elastic  compound.  The  spontaneous  polymerisation 
of  isoprene  after  9  months  is  also  recorded  by  ^^'eber  and  after 
3J  years  by  Pickles,  in  both  cases  the  caoutchouc  being  separated 
from  the  viscid  mass  by  addition  of  alcohol.  Last  year,  Harries 
was  able  to  announce  that  by  heating  isoprene  with  glacial 
acetic  acid  in  a  closed  tube  he  had  synthesized  rubber.  According 
to  him,  this  rubber  is  quite  as  tough  and  elastic  as  the  natural 
product,  but  the  process  is  very  costly.  Lebedeff's  method 
is  to  heat  isoprene  at  150°  C.  in  a  closed  vessel.  Recently,  sub- 
stances alhed  to  isoprene  have  been  treated  by  similar  methods 
with,  it  is  reported,  the  same  results. 

Cost  of  Manufacturing  Synthetic  Rubber. 

All  of  these  are  merely  laboratory  experiments,  and  all  that 
can  be  fairly  said  is  that  we  are  promised  rubber  upon  a  com- 
mercial scale,  with  the  bye-products  of  manufacture  to  lessen  the 
cost  of  production.  One  great  difficulty  is  to  prepare  isoprene 
cheaply  enough.  It  can  be  obtained  by,  say,  passing  turpentine 
through  a  red-hot  tube  ;  but,  according  to  tilden,  the  maximum 
yield  is  10  per  cent.  It  would  appear  that  the  isoprene  or  other 
intermediate  product  used  can  be  prepared  more  cheaply  from 
other  substances  than  turpentine,  though  at  what  cost  one  cannot 
say.  Some  degree  of  secrecy  is  being  maintained  by  most  of  the 
interested  parties  with  regard  to  the  financial  aspects  of  synthetic 
rubber  production,  and  the  actual  proportions  of  the  intermediate 
product — say  isoprene — obtained  from  the  raw  material,  together 
with  the  proportion  of  caoutchouc  yielded  by  the  intermediate 
product  is  not  a  matter  of  certainty.  Thus  it  is  difficult  to  discuss 
synthetic  rubber  from  the  financial  side.  The  price  of  American 
turpentine  is  now  (25th  November,  191 1),  3|d.  per  lb.     On  the 


PARA     RUBBER  467 

basis  of  a  ten  per  cent,  yield  of  isoprene  from  turpentine,  and,  as 
claimed  by  two  different  interests  exploiting  synthetic  rubber 
inventions  a  yield  of  15  and  50  per  cent,  of  ubber  respectively  from 
the  isoprene,  an  estimate  may  be  made  of  the  cost  of  the  raw 
materials,  to  which  must  be  added  factory  and  other  charges. 

But  attention  should  be  drawn  to  a  report  that  a  German 
firm  of  chemists  is  selling  synthetic  rubber  to  a  manufacturing  firm 
at  2s.  yd.  per  lb. 

MistrsE  OF  Term  "Synthetic  Rubber." 

It  is  now  time  to  strongly  object  to  the  gross  misuse 
of  the  term  ' '  synthetic  rubber. ' '  Its  application  to  any  substance 
which  is  remarkable  for  its  lightness  in  weight  or  great  elasticity 
is  not  justifiable,  and  in  my  opinion  should  never  be  allowed. 
Boiled  seaweeds  or  bones  give  light,  elastic,  gummy  substances, 
but  it  would  obviously  be  unfair  to  refer  to  these,  even  in  the  most 
popular  sense,  as  synthetic  rubbers.  Peaty  substances,  if  sub- 
jected to  bacteriological  treatment,  may  be  partly  transformed 
into  gummy  elastic  products  ;  but  whether  the  latter  should  be 
named  ' '  synthetic  rubber ' '  must  surely  depend  upon  the  results 
of  a  complete  analysis  of  the  products  formed.  High-grade 
and  low-grade  natural  rubbers,  when  mixed  with  balata  or  gummy 
extracts,  may  show  considerable  improvement  in  physical  properties 
and  this  may  be  especially  true  of  resinous,  low-grade  rubbers  ; 
but  no  chemist  would  allow  the  improved  product,  so  derived, 
to  pass  under  the  name  "synthetic  rubber."  Nevertheless,  the 
term  is  being  very  loosely  used  in  reference  to  substances  which 
are  merely  gummy  fermentations,  or  vulcanized  or  oxidized  oils,  or 
to  materials  which  have  as  their  basis  a  varying  proportion  ot 
natural  rubber. 

Rubber   Substitutes. 

Rubber  substitutes  are  already  largely  employed  in  the 
manufacture  of  certain  rubber  articles,  and  large  factories  have 
long  been  estabhshed  for  their  preparation.  Vulcanized  oils,  the 
preparation  of  which  is  rendered  possible  on  account  of  the  action 
of  sulphur  and  sulphur  chloride  on  various  oils  and  fats,  are 
largely  used  as  rubber  substitutes.  In  the  manufacture  of  these 
substitutes,  processes  somewhat  similar  to  those  used  in  ordinary 
vulcanization  are  carried  out ;  hence  the  reason  why  they  are 
described  as  vulcanized  oils.  Linseed,  rape,  poppy  seed,  cotton 
seed,  castor,  and  numerous  other  oils  are  used  in  this  way,  as  well 
as  substances  having  a  gummy  and  resinous  texture.  There  has 
never  been  any  attempt  at  secrecy  in  connection  with  the  use  of 
these  substitutes,  as  most  people  know  that  rubber  would  be  of 
very  Httle  use  if  it  were  not  mixed  and  compounded  with  such 
substances. 

Terry,  in  dealing  with  rubber  substitutes,  states  that  the 
efforts  inventors  have  made  to  discover  or  prepare  a  substitute 
for  rubber  have  been  very  noticeable,  but  up  to  the  present  time 


468  PARA     RUBBER 

no  real  substitute  has  been  discovered.  In  his  opinion,  the  sub- 
stitutes which  have  so  far  been  used  have  no  status  beyond  that  of 
cheapening  ingredients,  and  only  such  a  substance,  which  on 
admixture  with  rubber  cheapens  it  without  at  the  same  time 
reducing  its  quahty,  can  be  claimed  as  a  desirable  substitute.  He 
makes  a  pertinent  remark  to  the  effect  that  the  great  bulk  of  the 
rubber  substitute  inventions  have  benefited  no  one  except  those 
who  are  professionally  concerned  with  patents,  and  that  the 
present  prospects  of  wealth  for  the  discoverer  of  a  rubber  sub- 
stitute are  largely  illusionary.  It  is,  however,  pointed  out  that  in 
the  manufacture  of  rubber  articles  where  elasticity  is  not  reaUy 
required,  e.g.,  waterproof  goods,  doormats,  etc.,  certain  substances 
may  be  legitimately  used  which  will  not  impair  the  efficiency  of 
the  manufactured  article. 

Artificial  Rubbers. 

Artificial  rubbers  as  well  as  rubber  substitutes  are  often  met 
with.  They  are  substances  usually  derived  from  some  organic 
source,  and  generally  possess  one  or  more  of  the  physical  character- 
istics of  natural  rubber.  The  chemical  constituents  in  artificial 
rubbers  or  rubber  substitutes  need  not,  however,  be  even  remotely 
related,  chemically,  with  those  in  the  natural  article  ;  in  this 
particular  lies  one  of  the  great  differences  between  them  and  real 
synthetic  rubber. 

One  might  with  advantage  distinguish  between  artificial 
rubbers  and  rubber  substitutes  ;  the  former  being  roughly  de- 
fined as  substances  containing,  essentially,  a  quantity  of  natural 
rubber  together  with  other  substances  and  as  allied  to  natural  low- 
grade  rubbers,  and  the  latter  as  materials  derived  from  sources 
other  than  crude  rubbers. 

Composition  of  an  Artificial  Rubber. 

The  desire  to  place  on  the  market  a  comparatively  cheap 
composite  mixture  having  physical  properties  similar  to  raw 
rubber  is  strongly  marked.  From  time  to  time  samples  for  report 
and  analysis  are  received  ;  when  they  possess  characters  of  value 
to  rubber  manufacturers  they  usually  contain,  as  an  essential 
component,  a  proportion  of  rubber,  reclaimed  or  otherwise.  In  the 
"  Gummi-Zeitung "  an  account  is  given  of  material  submitted 
as  "  an  artificial  rubber  prepared  from  vegetable  fibres ' '  to  Marck- 
wald  and  Frank.  The  following  details  are  given  regarding  the 
composition  of  this  substance  : — 

/o  /c 

Moisture,  volatile  at  loo  deg.  C.       . .  .  .  12"86 

61-50 


Acetone  extract 
Which  consisted  of — 
Saponifiable  constituents 
Unsaponifiable  constituents 
Sulphur    . . 

Mineral  constituents  . . 

Sulphur  combined  with  rubber 

Rubber  substance 


9' 44 

49-88 

2-i8 

7-16 

3-00 

15-48 


PARA     RUBBER  469 

In  such  a  sample  it  is  obvious  that  100  parts  of  rubber  are 
combined  with  about  19  parts  of  sulphur.  The  mineral  constit- 
uents are  said  to  have  consisted  largely  of  alumina,  together 
with  iron  oxide  and  small  quantities  of  chalk  ;  magnesium 
carbonate  was  also  present.  Chemical  tests  further  revealed 
the  presence  of  starchy  and  resinous  compounds.  In  conclusion, 
it  is  stated  that  the  ' '  artificial  rubber ' '  under  investigation  may 
be  regarded  as  having  been  derived  from  an  inferior  reclaimed 
rubber  containing  sulphur  and  mineral  substances,  and  cannot 
lay  claim  to  being  an  artificial  rubber  in  the  true  sense  of  the  term. 

Improved  Low-Grade  Rubber.s. 

There  is  on  the  market  a  preparation,  made  by  a  secret 
process,  which  is  said  to  possess  excellent  qualities.  It  is  made 
essentially  from  guayule  rubber  and  certain  'gummy  substances, 
and  a  large  factory  has  been  established  for  its  manufacture. 
The  manufacture  of  this  substance — which  may  be  described 
as  an  artificial  or  modified  rubber — has  been  going  on  for  some  time, 
and  already  large  quantities  of  the  improved  product  are  being 
turned  out.  It  is  obvious,  however,  that  in  the  preparation  of 
this  class  of  rubber,  materials  very  expensive  in  themselves  have 
to  be  used,  guayule  rubber  alone  standing  at  2s.  jd.  per  lb.  (Feb., 
1912.)  Furthermore,  the  necessary  ingredients  are  obtained  from 
plants  which  grow  very  slowly,  and  the  method  of  extraction 
is  such  as  to  involve  the  destruction  of  the  plants  whence 
they  are  derived.  It  is,  therefore,  obvious  that  the  natural 
sources  of  supply  may  be  partially  exhausted  before  many  ^ears 
are  over.  But  what  puzzles  the  writer  is  that  this  new 
substance,  which  from  all  accounts  appears  to  be  nothing 
more  than  an  improved  low-grade  rubber,  should  have  been 
referred  to  as  "  synthetic  rubber. ' ' 

Reclaimed  and  Reformed   Rubber. 

At  the  present  time  there  is  a  ready  market  for  discarded 
rubber  goods,  the  rubber  being  reclaimed,  that  is,  devulcanized  as 
far  as  possible,  and  then  worked  up  again,  but  rarely  into  articles 
requiring  the  highest  class  of  rubber.  Such  reclaimed  rubber 
has  also  found  a  use  in  replacing  in  some  cases'  oil  substitutes. 
While  an  inexpensive  method  of  making  synthetic  rubber  is  a 
matter  of  remote  possibihty,  and  one  which  the  plantation  owner 
may  almost  ignore,  the  question  of  reclaimed  rubber  is  more 
insistent,  the  probability  being  that  in  course  of  time  this  sub- 
stance will  become  more  perfect  in  quality,  and  will  render  less 
necessary  the  use  of  the  first-grade  product.  The  popular  re- 
claiming methods  all  seem  to  have  a  prejudicial  effect  upon  the 
caoutchouc  hydrocarbon. 

The  general  principles  followed  are  very  varied.  The  first 
obvious  step  is  the  breaking-up  of  the  rubber  by  grinding  it  to 
a  powder  between  rollers,  where  that  is  possible  ;  or,  say,  as  in  one 
method,  by  cutting  it  up  with  knives  arranged  in  series.     Beyond 


470  PARA     RUBBER 

this  there  are  great  differences  in  procedure,  and  there  are  many 
patents  covering  this  part  of  the  process.  The  devulcanization 
may  be  performed  by  steaming  the  rubber  or  by  heating  it  in 
hot-air  stoves  with  resin-oil,  petroleum,  etc.,  preceded  by  treat- 
ment with  blasts  of  air  to  remove  any  fragments  of  fibre.  Other- 
wise alkalies  or  acids— which  also  destroy  the  fibres,  and  destroy 
or  dissolve  out  contained  oils  or  rubber  substitute — are  used  as 
devulcanizers.  Nowadays,  alkahes  are  generally  used.  Finally, 
the  rubber  is  washed,  dried,  and  rolled  into  sheets.  Some  pro- 
cesses involve  dissolving  out  the  rubber  by  means  of  such  solvents 
as  petroleum,  and  then  precipitating  it  by  means  of  alcohol. 

Reformed  differs  from  reclaimed  rubber  in  that  no  attempt 
is  made  to  devulcanize.  The  fragmented  rubber,  in  the  form 
of  powder  or  flakes,  to  which  oil  may  be  added,  is  directly  moulded 
by  heat  and  pressure  into  the  finished  article.  Satisfactory 
results  are  obtained,  the  homogeneous  mass,  on  cooling,  being 
indistinguishable  in  appearance  from  an  article  moulded  from 
first-hand  rubbers. 

Disuse  of  Rubber. 

In  some  countries  the  authorities  have  been  contemplating 
the  use  of  the  paper  and  dry-air  insulation  afforded  by  the  so-called 
dry  core  cables  for  underground  and  sub-aqueous  extensions,  but 
the  local  conditions  are  sometimes  so  peculiar  in  regard  to  the 
soil  and  the  atmosphere,  that  the  engineers  have  not  made  up 
their  minds  as  to  the  desirability  of  the  change  from  the  usual 
insulation.  Nevertheless,  cheap  substitutes  are  being  used  in 
cable  work  in  many  parts  of  the  world. 

Burgess  states  that  land  cable  carrying  telephone  wires, 
which  at  one  time  were  insulated  with  rubber,  are  now  largely 
insulated  with  dry  paper,  and  that  heavy  cables  for  electric  light 
supply  are  demanding  for  use  in  their  manufacture  less  and 
less  rubber  every  year,  its  place  being  taken  by  papier-mache 
and  cellulose  pulp.  He  attributes  this  to  the  high  price  of  raw 
rubber,  and  is  of  the  opinion  that  there  will  be  a  great  extension 
of  the  electrical  application  of  rubber  when  the  price  of  raw  rubber 
is  reduced. 

In  recent  years,  while  prices  for  rubber  goods  have  been 
abnormally  high,  there  have  been  still  other  instances  of  the 
gradual  disuse  of  rubber.  The  more  extensive  use  of  cork,  instead 
of  rubber,  in  door  mats,  and  the  substitution  of  metal  springs  for 
rubber  buffers  are  two  popular  examples.  On  the  other  hand 
great  advances  have  been  recorded  in  the  number  of  purposes  for 
which  rubber  can  be  used,  and  a  considerable  demand  has  been 
established  in  other  directions  in  which  our  product  has  long  been 
in  use.  The  disuse  of  rubber  \yill  not  be  of  any  consequence  so  long 
as  the  demand  in  old  applications  continues  to  grow  at  such 
rapid  rates. 


CHAPTER    XXX. 

THE  SEEDS  :  PROPERTIES,  USES  AND  DISTRIBUTION. 

It  is  well  known  that  trees  of  Hevea  hrasiliensis  in  the  East 
flower  and  fruit  after  their  fourth  or  fifth  years.  In  other  countries 
plants  raised  from  cuttings  have  been  known  to  produce  fruits 
within  three  years.  Each  fruit  usually  contains  three  seeds  ; 
the  number  of  seeds  annually  produced  per  tree  is  about  five 
hundred  when  the  trees  are  mature. 

The  following  interesting  information  was  pubhshed  in  the 
' '  Times  of  Ceylon ' '  regarding  the  number  of  seeds  capable  of 
being  produced  from  a  five-year-old  tree  and  its  offspring,  as- 
suming that  each  tree  after  attaining  its  fifth  year  produces  500 
seeds  annually,  and  that  all  germinate  : — 
Total  Seeds  at 


Year, 
ist 
2nd 
3rd 
4th 
6th 
8th 

loth 


end  of  each  year. 

Year. 

500 

nth 

1,000 

13th 

1,500 

15th 

2,000 

17th 

253,000 

1 8th 

1,504,000 

19th 

3.755.000 

20th 

Total  Seeds  at 

end  of  each  year. 

130.255.500 

1,259,006,500 

4.388,757,500 

323,019,508,500 

952,522,759,000 

2,208,151,259,500 

4,402,530,010,000 


At  the  present  time  there  are  about  220,000  acres  of  Hevea 
rubber  trees  in  Ceylon,  400,000  acres  in  Malaya,  and  very  large 
areas  in  other  parts  of  the  world.  It  is  obvious  from  a  glance 
at  the  above  table  that,  before  long,  very  large  quantities  of  seeds 
will  be  available. 


Decorticated  Seeds  :   Estimated  Annual  Crop. 

Basing  the  calculations  upon  the  assumptions  that  800,000 
acres  of  Hevea  now  planted  will  come  to  the  bearing  stage,  that 
100  is  the  average  number  of  trees  per  acre,  and  that  each  mature 
tree  produces  only  400  seeds,  then  32,000,000,000  seeds  wiU 
be  the  annual  crop.  If  we  accept  the  Peradeniya  estimate  that 
the  kernels  after  six  weeks'  natural  drying  weigh  700,000  to  the 
ton,  then  there  will  be  nearly  47,000  tons  of  decorticated  seed 
for  which  a  market  should  be  found.  Of  course,  the  Peradeniya 
estimate  was  based  upon  the  weighing  of  a  comparatively  small 
number  of  seeds. 

Weight  of  Seeds. 

Determinations  of  the  weight  of  seeds  have  been  made  at 
Peradeniya  (Circ.  R.B.G.,  Ceylon,  Vol.  IV.,  No.  11).  A  sample  of 
seed  in  course  of  shipment  had  been  taken  at  Colombo  and  the 


472  PARA     RUBBER 

weight  of  1,000  of  the  seeds  found  to  be  7-2  lb.  The  weight  of  1,000 
seeds  collected  at  Henaratgoda  and  despatched  to  Peradeniya 
and  weighed  the  same  day  was  8-5  lb. 

But  more  detailed  determinations  were  made  with  seeds 
from  tapped  or  untapped  trees,  and  the  amount  of  drying  that  took 
place  during  certain  intervals  was  measured.  Fresh  seeds  from 
20-year-old  untapped  trees  weighed  9-1  lb.  per  thousand  ;  from 
30-year-old  trees,  lightly  tapped  the  second  and  third  year  before, 
they  weighed  7-8  lb.  The  latter  group  of  trees  was  the  same 
from  which  the  late  J.  B.  Carruthers  got  the  seeds  five  years 
earher — when  the  trees  were  then  untapped — that  weighed 
9-1  lb.  per  thousand  :    an  exact  correspondence. 

After  six  weeks'  drying  in  open  dishes,  the  seeds  from  untapped 
trees  lost  17-6  per  cent,  in  weight,  and  those  from  the  tapped 
trees  20-i  per  cent  ;  a  detailed  experiment  showed  that  the  loss 
of  weight  took  place  almost  entirely  from  the  kernel.  The  seeds 
from  tapped  trees  were  smaller  and  individually  heavier  than  those 
from  the  untapped. 

When  fresh,  the  shells  of  the  seeds  from  untapped  trees 
were  35-2  per  cent,  of  the  total  weight,  and  the  kernels  64-8  per 
cent.  After  six  weeks'  drying,  the  weights  were  45-3  per  cent, 
and  547  per  cent,  respectively.  In  the  case  of  seeds  from  tapped 
trees  the  shells  weighed  42-2  per  cent,  of  the  total,  and  the  kernels 
57-8  per  cent.,  after  six  weeks'  drying.  The  authors  draw  atten- 
tion to  the  further  loss  of  weight  during  transit  to  England,  for 
the  director  of  the  Imperial  Institute  has  stated  that  the  kernels 
constitute  about  50  per  cent,  by  weight  of  the  whole  seeds  weighed 
in  England. 

A  planter  states  that  1,000  seeds  from  his  15-year-old  trees 
now  average  7  lb.,  and  formerly  seeds  from  the  same  trees  weighed 
10  lb.,  having  diminished  i  lb.  each  year  during  tapping. 

Value    of   Seeds   for   Export    Purposes. 

While  rubber  trees  are  yielding  such  large  quantities  of 
produce,  high  prices  are  ruling,  and  forests  are  being  extensively 
cleared  for  planting,  it  is  almost  unnatural  to  expect  planters  to 
trouble  themselves  with  the  subject  of  the  future  uses,  value,  and 
disposal  of  rubber  seed  supplies.  It  is,  nevertheless,  quite  patent 
that  when  an  estate  has  reached  its  fifth  year,  it  will  be  almost 
independent  of  outside  sources  for  seeds.  Since  there  is  no  limit 
to  the  area  to  be  planted  in  rubber,  there  must,  providing  the 
trees  continue  to  flourish,  ultimately  be  a  glut  in  the  seed  market. 
Considering  the  uses  to  which  the  various  parts  of  plants  are 
put  in  America,  the  manner  in  which  every  part  of  a  plant  can 
be  used  as  the  basis  for  the  manufacture  of  some  important  by- 
product, it  should  not  be  difficult  to  enhance  the  value  of  the 
surplus  rubber  seeds  by  facilitating  their  use  in  various  industries. 

On  the  value  of  seeds,  at  present,  for  export  purposes  little 
can  be  said  of  an  encouraging  nature.  The  determinations 
referred  to  above  show  that  taking  the  weight   of  1,000  seeds  as 


PARA     RUBBER 


473 


8  lb.,  the  loss  of  weight  on  drying  at  20  per  cent.,  and  the  weight 
of  the  kernel  as  50  per  cent,  of  the  whole  seed,  then 

T  ton  =  280,000  fresh  seeds. 
=  350,000  dried  seeds. 
=  700,000  kernels. 

It  is  pointed  out  that  this  estimate  is  too  favourable  on  each 
point,  but  accepting  it,  and  assuming  that  the  kernels  sell  for 
£10  per  ton,  then  the  gross  return  per  1,000  seeds  is  21-5  rupee 
cents.  Out  of  this  must  be  met  the  cost  of  collecting,  decorticating, 
and  the  freight,  insurance  and  general  charges. 

Form  in  which  to  Export  the  Seeds. 

According  to  Dunstan  it  is  useless  to  export  unshelled  seeds. 
The  shells  add  to  the  cost  of  freight,  and  have  to  be  removed 
eventually.  There  is  no  perfectly  satisfactory  shelling  machine 
for  these  nuts  on  the  market,  but  trials  at  the  Imperial  Institute 
show  that  "Miller's  Nutcracking  Machine"  gives  fairly  satis- 
factory results.  With  this  machine  the  broken  shells  have  to  be 
picked  out  by  hand,  but  this  can  be  done  by  children.  The 
kernels  should  be  dried  thoroughly  in  the  sun,  or  by  artificial 
heat,  as  rapidly  as  possible,  and  shipped  in  bags.  The  difficulties 
of  shelling  will  be  speedily  overcome  if  there  is  a  demand  for  the 
■  kernels. 


Estimated   Profit  from  Export  of   Seeds. 

As  already  pointed  out,  the  estimation  of  the  possible  profit 
by  collecting  and  exporting  the  seeds  is  difficult.  But  in  order 
to  obtain  some  guidance  upon  the  point,  the  following  calculations, 
based  upon  those  made  by  Mr.  Palmer  of  the  Brieh  Estate,  are 
given.  It  is  assumed  that  the  kernels  weigh  in  London  50  per 
cent,  of  the  whole  seed  and  that  700,000  weigh  a  ton  : — 

Costof  picking  700,000  seeds  at  4  cents,  per  1,000  ..  ..  $  yo 

Decorticating  2  tons           ..          ..  ..  ..  ..  ..  I4"0 

Gunnies  for  packing           ..  ..  ..  ..  2-4 

Packing,  weighing,  carting            .  .  .  .  .  .  ,  .  4-0 

Railway  freight,  at  20  c.  per  picul  ..  ..  ..  ..  3*4 

Shipping  charges,  insurance,  etc.  .  .  .  .  . .  .  .  8'o 

Freight  from  Port  Swettenham     ..  ..  ..  ..  ..  iS-o 

$56-8 

If  the  decorticated  seeds  realise  £10  a  ton  in  London,  this  allows 
of  a  profit  of  £2  5s.  per  ton.  Assuming  that  there  are  100  trees  to 
the  acre  and  that  a  tree  will  yield  400  seeds,  then  1,000  acres  will 
yield  40,000,000  seeds. _  These  seeds  ought  to  weigh  about  57 
tons,  and  the  profit  upon  an  estate  of  1,000  planted  acres  will  only 
be  £185  ;  ■  against  this,  certain  charges  must  be  made. 

This  estimate  is  a  conservative  one,  for  it  is  quite  possible 
that  more  than  ;fio  per  ton,  perhaps  double  this  figure,  can  be 
realized  in  London  ;  and  geographical  position  may  lessen  in  some 
cases  the  transport  charges.     But  taken  as  a  whole  it  is  not  very 


474  PARA     RUBBER 

promising.  Possibly,  after  all,  crushing  the  seed  on  the  spot  by 
necessarily  crude  methods,  and  using  the  poonac  as  manure,  may 
reward  the  planter  best. 

The  Oil  in  Hevea  Seeds. 

As  far  back  as  the  year  1872  Collins  stated  that  the  oil  was 
said  to  be  of  use  in  the  preparation  of  varnishes.  And  scientific 
investigations  have  shown  that  it  is  suita.ble  as  a  substitute  for 
hnseed  oil  and  similar  drying  oils.  Technical  trials  by  manu- 
facturers have  confirmed  this  view. 

In  January,  1911,  the  Director  of  the  Imperial  Institute  drew 
attention  to  the  fact  that  enquiries  from  manufacturers  desirous 
of  obtaining  suppHes  of  Hevea  seed  kernels  or  oil  had  been  received 
there. 

The  oil  was  valued  in  1903  at  £20  per  ton,  and  the  cake  at 
£5  to  £6  per  ton.  From  £10  to  £12  per  ton  was  the  estimated 
value  of  the  decorticated  seeds.  Since  the  year  1903,  the  prices 
of  oil  seeds  and  oils  have  very  much  advanced.  For  example, 
linseed  oil,  worth,  on  the  average,  not  much  more  than  £20  a  ton 
in  1903,  has  been  more  than  £40  a  ton  on  the  average  during  1911. 

The  report  made  by  the  Imperial  Institute  (Bull.  Imp.  Inst., 
1903),  upon  the  oil  is  as  follows  : — 

"The  kernels  constitute  about  50  per  cent,  by  weight  of  the 
whole  seeds  and  yield  42-3  per  cent,  of  oil.  The  husk  and  kernel 
together  yield  20  per  cent,  of  oil.  The  oil  is  clear,  light  yellow  in 
colour,  and  on  saponification  with  caustic  soda,  furnishes  a  soft 
soap  of  yellowish  colour.  If  the  seed  has  been  ground  to  a  meal, 
the  oil  extracted  is  solid  owing  to  decomposition  ;  but  that 
expressed  from  the  freshly-ground  seed  is  liquid.  The  husks  contain 
a  solid  fat  in  small  quantities." 

An  experiment  was  made  in  1911  at  Peradeniya  in  expressing 
the  oil  from  dried  kernels  in  a  "  chekku  mill. ' '  The  percentage 
of  oil  obtained  was  17-75.  The  residue  was  an  oily  poonac  that 
would  not  bind. 

Hevea   Seed   Meal   and   Cake. 

Old  ground  seed  so  finely  divided  as  to  form  a  meal  was  re- 
ported upon  by  the  Imperial  Institute  : — 

Chemical  Analysis. 

per  cent.  per  cent. 

Moisture  .  .  .  .     9'  i  Oil  .  .  . .  36'  i 

Ash  .  .     3'53  Proteins         . .  . .  i8'2 

Fibre  .  .     3'4  Carbohydrates  . .  29-67 

The  ash  was  found  to  contain  30-3  per  cent,  of  phosphoric  acid 
present  in  the  form  of  phosphates,  which  is  equivalent  to  1-07  per 
cent,  of  phosphoric  acid  in  the  meal. 

The  meal  thus  prepared  is  unsuited  for  cattle  food  on  account 
of  the  large  quantities  of  free  fatty  acids,  and  cannot  be  used  for  oil 
extraction.  "It  is  probable,  however,  that  if  the  oil  were  ex- 
pressed from  the  decorticated  seeds,  the  residual  cake  could  be 


PARA     RUBBER 


475 


utilised  as  a  feeding  material,  as  is  shown  by  the  following  com- 
parison between  the  calculated  composition  of  such  a  cake  and  the 
composition  of  some  commercial  feeding  cakes. ' ' 
Calculated 


Moisture 

Ash 

Proteins  .  . 

Fibre 

Fat 

Carbohydrates 

Nutrient  value 

These  figures  show  that  a  cake  prepared  from  Hevea  rubber 
seed  meal  may  form  a  good  cattle  food,  and  that  it  contains  very 
little  indigestible  matter. 

"  So  far  it  has  been  impossible  to  obtain  sufficiently  large 
supplies  of  the  cake  to  permit  of  feeding  trials  being  made.  More- 
over, the  cake  has  been  found  to  yield  small  quantities  of  prussic 
acid.  This  is,  of  course,  also  true  of  linseed  cake,  but  the  fact 
makes  it  very  important  that  feeding  trials  should  be  made  at  the 
earliest  opportunity.  In  Ceylon  it  is  certain  that  the  cake  would 
be  valuable  as  a  manure. ' ' 


Composition 

Linseed  Cake. 

Cotton  Seed 

of  Hevea 

New 

Old 

Cake. 

Seed  Cake. 

0/ 

Process. 
0/ 

Process. 

0/ 

New  process. 

0/ 

/o 

13-36 

/o 
9-4 

/o 
IO-8 

/o 
II-I 

5-19 

5-4 

5-0 

6-1 

26-81 

35-6 

28-6 

38-47 

5' 00 

yi 

6-7 

9-78 

6-00 

7'5 

10-6 

8-78 

4364 

35'o 

38-3 

25-75 

84-25 

87-85 

91-28 

84-4 

Experiments  with  Hevea  Oil  and  Cake. 

Some  seeds  were  sent  by  Mr.  Kirk,  of  Malabar,  to  Messrs. 
Peirce,  Leslie  and  Co.,  for  oil  extraction  and  determination  of 
the  manurial  value  of  the  poonac.  The  experiments  were  not 
altogether  successful  as  the  machinery  available  was  not  very 
efficient.  The  results  indicate,  at  least,  that  the  poonac  is  likely 
to  prove  a  valuable  fertiliser.  There  were  operated  upon  1,133  lb. 
of  seeds,  from  which  were  obtained  361  lb.  of  kernels  (or  32  per  cent, 
of  the  whole)  and  772  lb.  of  husk  (or  68  per  cent.).  When  crushed, 
the  kernels  yielded  38  lb.  of  oil  (or  10-5  per  cent.)  and  260  lb.  of 
poonac,  a  loss  of  63  lb.  Such  a  disappointing  yield  of  oil  was  due 
to  the  oil  left  in  the  poonac,  the  latter  still  contained  33  per  cent, 
of  it.      Thus  the  kernels  originally  contained  34  per  cent,  of  oil. 

In  the  first  column  of  the  annexed  table  is  shown  the  analysis 
of  this  poonac  ;  in  the  second  a  calculated  analysis  when  free  of 
oil ;   in  the  third  an  analysis  of  dried  castor  poonac  : — 

0/  0/  0/ 

/o  /o  /o 

Moisture      . .          . .           6-40  9-55  — 

(a)  Organic  matter       ..         55-12  82-27  9i'59 

Oil    . .          . .          .  .         33-00  —  — 

Ash 5-48  8-18  8-50 


5-74 


(a)  Containing  nitrogen  3-49  5-29  ^  ,  , 

The  ash  contained  15-12  per  cent,  of  phosphoric  acid  and  12-93 
per  cent,  of  potassium  ;  calculating  the  percentages  in  the  oil- 
free 'poonac  they  are  1-23  and  i-o6  respectively,  the  percentages  in 


476  PARA     RUBBER 

castor  poonac  being  i-8  and  i-2.  The  percentage  of  nitrogen  in 
oil-free  Hevea  poonac  is  as  favourable  as  that  shown  in  the  castor 
poonac  analysis,  in  which  the  moisture  is  not  included. 

Transport  of  Seeds  to  Oversea  Plantations. 

The  difficulty  of  transmitting  seeds  of  Hevea  brasiliensis  to 
distant  countries  is  well  known  ;  the  seeds  do  not  retain  their 
germinating  capacity  for  a  very  long  time  unless  great  care  is 
taken  in  collecting  and  packing  operations. 

The  two  most  important  factors  are  that  the  packing  material 
should  not  be  one  that  will  allow  moulds  or  bacteria  to  develop, 
and  that  it  should  be  dry  enough  to  pre\'ent  the  seeds  germinating 
and  yet  moist  enough  to  prevent  their  being  killed  by  drying. 
Other  factors  are  mentioned  in  the  notes  below. 

There  is  some  advantage  usually  in  sending  packages  of  seeds 
by  parcel-post  instead  of  by  ordinary  freight.  As  the  passage  is 
shortened  and  the  percentage  of  germinating  seeds  increased,  it 
will  generally  be  found  that  while  the  total  cost  per  despatched 
seed  is  higher,  the  cost  per  germinated  seed  is  lower. 

Success  in  germination  also  depends,  to  some  extent,  upon  the 
shortness  of  the  time  elapsing  between  the  falling  from  the  trees  and 
the  packing. 

The  Method  of  Packing  at  Trinidad. 

The  late  J.  H.  Hart,  of  Trinidad,  assured  me  that  he  always 
kept  Hevea  seeds  damp  and  never  dried  them,  and  that  he  objected 
to  the  use  of  charcoal  in  packing  as  he  believed  the  latter  abstracted 
the  moisture  from  the  seeds.  Mr.  Hart  informed  me  that  coconut 
dust  was  best  when  ' '  tobacco  damp, ' '  and  seeds  packed  with 
this  material,  in  small  tins  of  1  lb.  or  so,  kept  sound,  germinated 
freely,  and  did  well  when  disentangled.  One  maj'  presume  that 
the  seeds  sent  under  these  conditions  had  onlv  a  short  journey  to 
go. 

The   Method   of   Packing  at  Singapore. 

The  Director,  Botanic  Gardens,  Singapore,  has  sent  quantities 
of  Hevea  seed  as  far  as  Jamaica,  Kew,  ^Mexico,  etc.,  with  satis- 
factory results.  The  seeds  were  sent  to  Jamaica  in  biscuit  tins, 
packed  in  slightly  damped  incinerator  earth,  \nth  the  upper  part 
filled  with  sawdust  to  reduce  the  weight.  The  other  seeds  were 
sent  in  biscuit  tins  filled  with  damp,  finely- powdered  charcoal. 

"In  packing  a  certain  amount  of  care  is  required  (Str.  Bull., 
1906^  in  damping  the  charcoal  so  as  to  get  it  equally  moistened 
all  through  and  not  either  over  wet  or  over  dry.  This  is  best 
done  by  damping  it  thoroughly  and  then  drying  it  in  the  sun, 
consistently  stirring  and  turning  it  o\'er  till  it  is  uniformly  slightly 
damped.  The  incinerator  earth,  which  had  been  exposed  to  the 
elements,  was  damp  when  received,  and  only"  wanted  partial  drying 
to  fit  it  for  packing.  Its  weight  is  against  its  use,  but  both  it  and 
the  powdered  charcoal  have  the  great  advantage  of  preventing 


PARA     RUBBER  477 

attacks  of  mould  or  bacteria  likely  to  cause  decomposition.  Other 
experiments  with  powdered  coir  fibre  and  coirdust,  sawdust,  and 
variously  prepared  soils  have  been  tried,  but  the  results  do  not 
seem  to  have  ever  been  as  successful. ' ' 

On  the  occasion  of  my  visit  to  Singapore  in  1908  (My  Tour 
in  Eastern  Rubber  Lands)  I  noted  what  was  the  usual  practice 
of  the  authorities  there.  Good  results  have  always  been  got  by 
packing  in  burnt  rice  husks.  The  old  husks  are  obtained  from  the 
padi  mills  and  burnt  ;  the  residue  consists  largely  of  finely- 
divided  charcoal,  very  light  in  weight.  Before  the  seeds  are  packed 
in  it,  the  dust  is  sprinkled  with  water.  One  kerosene  tin  holds 
about  600  seeds  ;  the  tins  are  sealed  in  the  ordinary  way.  After 
a  journey  of  over  four  months,  60  per  cent,  of  the  seeds  germinated. 
Mr.  Ridley  is  strongly  against  using  coconut  dust  and  sawdust. 

The  Method  of  Packing  at  Peradeniya. 

I  am  obliged  to  Mr.  H.  F.  Macmillan,  Curator  of  the  Royal 
Botanic  Gardens,  Peradeniya,  for  the  following  notes  on  the 
methods  of  drying  and  packing  seeds  of  Hevea  brasiliensis  : — 

"Unless  the  seeds  are  sown  or  despatched  almost  as  soon  as 
collected,  they  should  be  spread  on  a  dry  cool  floor,  and  turned 
over  frequently  to  prevent  heating.  It  is  often  unavoidably 
necessary  to  keep  the  seeds  on  hand  for  several  days,  and  an 
important  question  is  the  condition  under  which  they  may  be 
stored  to  preserve  their  vitality  best.  When  a  large  amount 
has  to  be  dealt  with,  a  quantity  of  broken-up  charcoal  should  be 
in  readiness  for  mixing  with  these,  or,  if  this  be  not  available,  dry 
sand  may  with  advantage  be  used  instead.  On  no  account 
should  the  seeds  be  covered  or  surrounded  with  any  damp  material ; 
lior  should  they,  on  the  other  hand,  be  unduly  exposed  to  sun  heat. 
Small  quantities  of  Hevea  seeds  rnay  be  packed  with  coconut 
dust  in  biscuit  or  tobacco  tins  and  sent  long  journeys  by  post.  On 
short  journeys  not  exceeding  six  or  seven  days  they  may  be  sent 
by  post,  without  any  packing,  in  small  gunny  bags  holding  500 
and  weighing  about  6  pounds.  Obviously,  however,  this  would 
not  be  practicable  for  a  large  quantity,  even  if  the  postage  were 
not  prohibitive.  For  journeys  of  about  a  fortnight  to  three  weeks 
ordinary  strong  cases,  about  30"  by  16"  by  12",  and  holding 
when  packed  6,000  to  7,000  seeds  may  be  used.  A  thin  layer  of 
dry  charcoal  mixture  is  placed  in  the  bottom  of  the  case,  then 
a  covering  of  paper  (to  prevent  the  compost  filtering  to  one  side 
in  transit),  next  a  layer  of  seed  followed  by  mixture,  and  so  on. 
One  part  charcoal  to  two  of  coconut  dust  or  sawdust  is  very 
satisfactory.  This  has  also  the  merit  of  being  light  in  weight, 
which  is  a  consideration  in  transport  charges.  It  must  be  remem- 
bered, however,  that  the  success  of  this  method  depends  upon  the 
freshness  of  the  seed  as  well  as  on  the  length  of  journey.  The 
method  of  packing  the  seed  in  sealed  kerosine  oil  tins  has  been 
tried,  but  with  indifferent  results.  Treating  the  seed  with  a  4 
per  cent,  solution  of  copper  sulphate  or  formalin  may  have  the 


478  PARA     RUBBER 

effect  of  preventing  the  growth  of  mould  on  the  seeds  and  thus 
prolonging  their  vitality,  but  its  application  is  unnecessary,  except 
perhaps  in  extreme  cases.  By  far  the  most  satisfactory  means 
of  transporting  Hevea  seeds  is  by  way  of  Wardian  cases. 

History  of  Certain  Consignments. 

It  was  reported  by  the  late  J.  K.  Nock,  Hakgala,  Ceylon, 
that  on  August  25th,  1908,  some  1,500  seeds,  packed  in  powdered 
charcoal  and  coir  dust  (mixed  in  equal  parts  and  slightly  damped) 
in  ordinary  biscuit  tins,  were  despatched  to  India.  "  The  consignee 
could  not  be  traced,  and  the  seeds  were  returned  on  November 
4th,  or  72  days  after  despatch.  They  were  at  once  sown  in  an 
open  bed,  and  no  less  than^496  plants  were  raised,  the  last  seed 
germinating  on  December  20th,  or  144  days  after  gathering. 
This  number  would  have  been  exceeded  had  not  porcupines 
visited  the  bed  and  routed  out  the  seeds  a  week  or  two  after 
germination  had  commenced.-  Out  of  1,000  seeds  forwarded  to 
the  Botanic  Station,  Seychelles,  750  plants  were  raised. 

In  the  same  year  10  packages  (total  2,059  seeds)  were  sent 
from  Ceylon  to  St.  Lucia  in  charcoal  dust,  and  occupied  two 
months  in  transit.  Success  was  obtained  with  948  seeds,  or 
about  46  per  cent.  It  was  asserted  that  the  best  results  were  got 
from  seeds  in  tins  the  charcoal  of  which  was  dry  on  arrival. 

From  500  seeds  supplied  by  a  Ceylon  seedsman  to  the  Gold 
Coast  Botanical  Department  in  November,  1900,  200  plants  were 
raised.  The  seeds  were  packed  in  tins  with  charcoal,  and  were 
two  months  in  transit. 

Of  various  consignments  totalling  172,957  seeds  despatched 
between  1907  and  1910  from  the  Singapore  Botanic  Gardens 
to  the  Georgetown  Botanic  Gardens,  British  Guiana,  134,419 
germinated,  or  777  per  cent.  The  journey  occupies  about  60 
days.  It  has  apparently  been  demonstrated  that  the  best  method 
of  forwarding  is  by  parcel-post  in  biscuit  tins  holding  about  600 
seeds  and  packed  in  weathered,  charred  rice  husks.  One  lot 
of  50,600  seeds  sent  in  this  way  cost  on  arrival  about  1-2  cents, 
each.  A  comparison  was  made  by  Professor  Harrison  of  two 
lots  of  seeds,  one  from  the  Singapore  Gardens,  the  other  from 
a  Malayan  estate.  Both  lots  were  packed  in  charred  rice  dust, 
but  the  latter  were  in  hermetically-sealed  tins,  and  were  so  closely 
packed  that  they  almost  touched,  there  being  823  in  a  tin,  whereas 
of  the  former  there  were  only  600.  The  latter  consignment  had 
partly  fermented  on  the  journey  and  only  19  per  1,000  germinated, 
while  702  per  1,000  germinated  in  the  former  case.  Harrison 
ascribed  the  success  of  the  Singapore  consignment  to  the  seeds 
being  able  to  get  sufficient  oxygen  for  retaining  their  vitahty. 

Possible  Superiority  of  Autumn  Crops  of  Seeds. 

The  season  at  which  Hevea  seeds  ripen  may  have  something 
to  do  with  their  germinating  capacity  after  a  long  voyage.  The 
following  table  shows  the  fate  of  seeds  sent  from  the  Singapore 


PARA     RUBBER  479 

Botanic  Gardens  to  the  Georgetown  Botanic  Gardens,  British 
Guiana,  from  which  it  will  be  seen  that  the  autumn  crop  was 
superior  : — 


No.  of  Seeds 

Germinated. 

sent. 

Number. 

Percentage. 

1907-8 

10,800 

Spring  Crop 

6,955 

64-40 

do. 

52,000 

Autumn  Crop 

42,100 

8o-oo 

1908-9 

50.000 

Autumn  Crop 

43.150 

86-30 

1909-10 

30.131 

Autumn  Crop 

21,609 

70-00 

1910-11 

29,676 

Spring  Crop 

20,465 

68-90 

do. 

303 

Intermediate  Crop 

139 

46-00 

A  greater  difference  has  been  experienced  in  Surinam  with 
seeds  from  the  same  source.  Of  the  seeds  arriving  in  September, 
October,  and  November,  from  50  to  80  per  cent,  were  good,  while 
only  15  per  cent,  of  those  coming  in  February,  March,  and  April 
germinated. 

The  explanation  of  this  difference  given  by  Ridley  is  this  : 
"It  is  possible  that  this  is  due  to  the  drier  weather  about  the 
time  of  ripening  of  the  autumn  crop.  The  spring  crop  comes 
on  early  in  the  year,  just  after  or  during  the  rains.  The  seeds 
are  only  thrown  from  the  capsule  during  sunshine,  and  it  fre- 
quently happens  that  when  they  are  actually  ripe,  the  days  are 
dull  and  wet,  and  the  seeds  are  retained  in  the  capsule  till  the 
first  fine  day.  In  this  case  they  have,  it  appears,  a  tendency  to 
commence  germination  in  the  capsule,  and  even  if  the  radicle  is 
not  protruded,  the  earlier  preliminary  stages  may  take  place 
without  any  external  symptons.  Such  seeds,  when  travelling, 
doubtless  receive  a  check  in  growth  which  causes  their  death. ' ' 

Wardian   Cases. 

The  principle  of  the  foregoing  methods,  it  will  be  seen,  is  to 
retard  the  effort  of  the  seed  to  germinate  and  remove  conditions 
which  induce  germination  ;  that  of  the  Wardian  case  is  to 
encourage  germination  ;  for  the  seeds  being  sown,  not  "packed," 
are  at  once  encouraged  to  germinate  and  grow  into  plants.  The 
initial  cost  in  this  instance  is  greater,  but  there  may  be  a  saving  in 
the  long  run.  If  good  seeds  are  sown,  they  will  germinate  in  about 
ten  or  twelve  days,  and  the  percentage  of  failures  should  be  nil  ; 
the  seedlings  may  then  be  tended  in  the  cases  as  if  they  were  in  a 
nursery  bed,  and  an  opportunity  of  shipping  may  be  awaited  with- 
out risk  or  anxiety.  Thus  on  arrival  at  destination,  instead  of 
receiving  seed  with  a  doubtful  percentage  of  germinating  power,  you 
should  have  good-sized  plants  or  "stijmps. "  The  principle 
of  the  Wardian  case  consists  of  filling  the  body  of  the  latter 
to  a  depth  of  five  inches  with  a  light  porous  compost  (say 
two  parts  leaf-mould  to  one  of  decayed  coconut  dust,  with 
a  sprinkling  of  charcoal)  ;  upon  this  is  placed  a  layer  [of 
about  1,500  seeds  (or  if  necessary  two  layers  of  1,000  each 
with  co/npost  between),  finishing  with  a  covering  of  about 
an  inch   of  compost.     The   whole  is   then  thoroughly  watered, 


48o  PARA     RUBBER 

after  which  small  bamboo  twigs  are  placed  thinly  and  longitudi- 
nally on  top  ;  across  these  are  placed  narrow  battens  three  inches 
apart,  these  being  kept  in  place  by  a  longitudinal  strip  nailed 
along  both  sides  of  the  case.  The  latter  is  then  raised  on  four 
bricks  to  allow  the  escape  of  water  as  well  as  to  prevent  attack 
by  white  ants.  The  contents  must  be  kept  moist  by  watering 
them  each  day  if  the  weather  be  dry.  It  is  best  to  allow  the 
seeds  to  germinate  before  despatching.  The  two  glazed  top 
sides  are  left  off  to  the  last.  These  when  screwed  on  admit  the 
necessary  hght,  whilst  fresh  air  is  provided  by  a  ventilator  in  each 
end  covered  with  fine  gauze  with  a  box  nailed  on  to  the  inside  for 
preventing  sea  spray  reaching  the  plants.  The  advantage  of  thus 
having  plants  instead  of  seeds  at  destination  may  mean  a  year 
gained  in  planting. 

Ridley  maintains  that  Wardian  cases  are  expensive  and 
unsatisfactory,  and  considers  that  the  method  adopted  in 
Singapore  of  packing  in  shghtly-daraped  charcoal  or  burnt  rice- 
dust  gives  better  results. 


Forwarding  of  Stumps  Oversea. 

Success  with  stumps  shipped  oversea  seems  to  depend  upon 
the  care  taken  to  maintain  a  sufficient  degree  of  humidity  within 
the  packing  or  Wardian  cases.  If  the  journey  occupies  more  than 
a  week  it  is  advisable  that  some  one  should  accompany  the  con- 
signment to  perform  a  daily  sprinkling  with  water. 

Perhaps  the  most  successful  result  obtained  with  stumps 
after  a  long  journey  is  the  following  :  out  of  100,000  stumps 
sent  from  Ceylon  to  Samoa,  at  least  98  per  cent.  grew.  The 
seedlings  were  taken  out  of  the  nursery  beds  when  less  than  20 
inches  high.  Their  crowns  were  cut  off,  and  a  stem  of  12  inches 
left.  The  tap-roots  were  cut  down  to  4  inches.  They  were 
packed  in  petroleum  tanks  in  a  mixture  of  sand,  mould,  coconut 
fibres,  etc.,  with  a  layer  of  moistened  loam  at  the  base.  The 
mixture  was  maintained  on  the  journey,  which  took  six  weeks, 
and  some  days  elapsed  before  all  were  put  into  the  ground. 

But  not  all  consignments  are  so  successful.  One  learns 
that  only  4,000  trees  were  got  from  80,000  stumps  sent  from 
Ceylon  to  Surinam.  Probably  these  were  not  attended  to  during 
transit.  Properly  treated  on  the  voyage,  stumps  are  superior 
to  seeds  ;  there  is  also  an  advantage  in  the  time  saved  in  pro- 
pagation. But  whether  or  not  the  extra  expense  is  justified  is  a 
matter  for  individual  consideration. 

How  successful  stumps  may  be  on  oversea  voyages  when 
properly  cared  for  is  shown  by  the  results  obtained  by  Mr. 
Stuart  R.  Cope,  who  has  his  consignments  regularly  watered  on 
the  voyage.  I  am  informed  that  in  the  case  of  a  consignment 
of  50,000  sent  from  Ceylon  to  Cameroon,  the  actual  delivery, 
"  live  and  in  good  condition,"  was  43,726. 


PARA     RUBBER  481 

Straightening  Curled  Roots. 

When  stumps  or  seedlings  arrive  from  a  distant  country  the 
roots  are  often  considerably  twisted  and  cannot  therefore  be 
placed  in  nursery  soil  except  the  curled  roots  are  cut  away.  In 
such  cases  it  is  advisable  to  lay  the  plants  out  on  planks,  cover 
with  soil  and  sprinkle  water,  and  allow  them  to  remain  in  that 
state  for  a  few  days  in  order  that  the  roots  may  have  a  chance  to 
straighten  themselves  as  much  as  possible. 


EE 


CHAPTER    XXXI. 

DISEASES    AND     PESTS     OF     HEVEA    TREES. 

It  is  often  relatively  easy  to  successfully  grow  a  small  number 
of  plants  in  any  particular  district  without  their  suffering  from  the 
ravages  of  innumerable  insects  and  fungi.  But  if  the  same  crop  is 
grown  on  a  large  scale  matters  often  take  a  different  turn.  It  has 
frequently  been  my  experience  when  dealing  with  minor  pro- 
ducts on  a  small  scale  to  find  that  the  diseases  to  which  they  were 
subject  never  developed  to  a  serious  extent,  but  when  once  the 
product  was  greatly  extended  the  insignificant  diseases  became  a 
serious  menace  to  the  plants  and  often  rendered  further  cultivation 
impossible. 

It  would  appear  on  first  consideration  that  any  pest,  which 
found  a  desirable  means  of  sustenance  on  the  tissues  of  a  particular 
plant,  would  increase  to  such  an  extent  that  the  few  host  plants  in 
the  neighbourhood  would  be  exterminated.  But,  for  some  reason 
or  other,  many  pests  do  not  appear  to  behave  in  this  manner,  and  it 
is  only  when  the  host  plant  occurs  in  large  numbers  and  over  exten- 
sive areas  that  anything  like  an  epidemic  is  noticeable. 

Specific  Hosts  for  Fungi  and  Insects. 

Perhaps  the  occurrence  in  large  numbers  of  the  host  plant  in 
widely-separated  districts  ensures  that  the  pests  will  find  the 
requisite  means  of  sustenance,  no  matter  where  they  occur,  and 
their  propagation  be  thereby  ensured.  The  larger  their  food 
supply,  the  quicker  they  will  increase  in  number  and  ultimately 
prove  more  serious  to  the  crop  on  which  they  are  living.  On  these 
grounds  the  contention  of  Colombo  friends  "that  the  cultivation 
of  Hevea  to  the  exclusion  of  other  kinds  of  rubber  is  a  dangerous 
system"  has  probably  much  to  recommend  it.  On  some  large 
estates  the  Hevea  trees  are  being  grouped,  and  each  group  is 
separated  from  its  neighbour  by  a  belt  of  other  trees.  Such  a 
belt  would  prevent,  to  a  certain  extent,  the  spread  of  pests  and 
diseases,  and  ne  might  be  able  to  more  easily  combat  insect  or 
fungus  pests,  as  soon  as  they  made  their  appearance  on  the 
enclosed  rubber  tress. 

It  has  been  conclusively  proved  that  many  parasites  on 
cultivated  plants  have  specific  or  generic  hosts  ;  they  usually 
confine  themselves  to  a  single  species  or  groups  of  allied  plants. 
Certain  fungi  which  now  thrive  on  cacao  pods  do  not  attack  tea 
plants  in  the  same  district ;  one  which  attacks  rubber  plants  will 
probably  not  damage  cinchona  ;    each  pest  thrives  best  and  often 


PARA     RUBBER  483 

only  on  a  particular  product.  The  pests  appear  to  become  estab- 
lished and  effect  the  greatest  damage  wherever  a  very  large  acreage 
is  occupied  by  only  one  cultivated  product  ;  wherever  the  insects 
or  fungi  are  carried,  a  fresh  source  of  the  same  food  is  at  hand,  and 
in  consequence  of  this,  the  parasites,  though  blown  about  for  many 
miles,  are  rarely  deposited  in  areas  where  a  food  supply  is  not 
available.  Though  this  is  the  case  it  must  not  be  lost  sight  of 
that  many  fungi  have  wide  powers  of  adaptability  and  may  select 
new  hosts  when  least  expected  to  do  so. 

Protective  Belts  of  Trees. 

A  fungus  which  thrives  on  coffee  leaves  and  kills  them  would 
probably  die  of  starvation  if  placed  on  a  tea  plantation  where  only 
tea  leaves  were  available.  It  may  be  generally  stated  that  a  large 
acreage  uninterrupted  with  other  species  affords  one  of  the  best 
means  of  propagating  parasitic  species  !  It  is  essential  that,  in 
order  to  check  the  spread  of  insect  and  fungus  pests,  the  protective 
belts  of  trees,  virgin  or  planted,  shall  be  composed  of  species 
unlike — botanically — those  to  be  protected.  For  instance,  in 
some  parts  of  Java,  the  cacao  and  rubber  trees  are  arranged  in 
separate  patches,  so  that  the  rows  of  rubber  trees  form  distinct 
belts  between  parallel  groups  of  cacao  trees.  One  plan  which  has 
been  suggested  is  to  plant  five  or  more  lines  of  cacao,  the  lines  to 
be  10  to  15  feet  apart  ;  interplant  these  with  Dadap  shade  trees,  if 
necessary,  then  plant  three  or  six  lines  of  rubber,  t'he  lines  to  be 
10  to  20  feet  apart. 

A  belt  of  jungle  not  possessing  these  cultivated  trees  will 
arrest  parasitic  insects  and  fungi,  but  may  not  feed  them  ;  if 
these  parasitic  organisms  are  kept  from  their  host  plants  they  are 
apt  to  die  or  degenerate,  the  belts  thus  serving  as  traps. 

Forest  Belts   and   Harbouring  Disease. 

But  some  reservation  must  be  made  to  the  statement  that 
jungle  belts  always  protect  cultivated  trees  against  diseases. 
It  may  be  fully  accepted  that  the  spores  of  "pink  disease"  and 
"dieback"  are  car  ied  at  monsoon  time  from  the  jungle,  which 
serves  as  a  nursery  for  the  disease,  a  factor  that  necessitates 
constant  watchfulness.  As  other  diseases  may  also  be  harboured 
by  certain  jungle  trees,  one  begins  to  feel  somewhat  dubious  about 
the  principle  of  jungle  belts.  I  cannot  help  believing  that  many 
of  the  organisms  attacking  cultivated  plants  in  the  tropics  have 
always  been  in  those  areas,  and  are  able  to  accommodate  them- 
selves to  the  new  food  supplies  presented  in  vast  areas  of  the 
same  species  under  cultivation. 

Forest  Belts  in  Malaya. 

The  idea  that  all  parasites  come  from  the  jungle,  and  that 
forest  belts  may  therefore  harbour  pests,  is  one  which  is  frequently 
brought  forward  ;  it  is  admitted  that  the  origin  of  parasites  in 
the  tropics  is  sometimes  very  problematical.     Everyone,  however, 


484  PARA     RUBBER 

with  tropical  experience  is  convinced  that  small  properties  are 
generally  freer  from  pests  than  large  ones,  and  that  barriers  in  the 
form  of  belts  of  unlike  species  generally  assist  one  in  keeping 
diseases  at  the  minimum.  The  retention  of  barriers  of  virgin 
forest  has  been  brought  into  force  in  the  F.M.S.  by  the  Government 
Botanist.  There  one  very  large  tract  of  forest  has  been  retained 
in  a  certain  district.  Prominent  agriculturists  have  expressed 
their  approval  of  this  system. 

Advantages  of  Mixed  Products. 

Mr.  Green,  Government  Entomologist,  Ceylon,  has  stated 
the  case  as  follows  : — ' '  The  history  of  every  cultivation  has 
shown  that  with  increase  of  area  and  lapse  of  time,  new  pests  arise, 
attracted  by  the  altered  conditions  and  an  abundant  supply  of  food. 
Our  Ceylon  system  of  exclusive  cultivation  of  single  products, 
though  convenient  for  economic  purposes,  lends  itself  to  the  rapid 
spread  of  pests  and  calls  for  special  measures  to  meet  this  liability. 
Plants  in  their  natural  state — where  numerous  orders,  genera  and 
species  are  intimately  mingled  together — are  not  nearly  so  subject 
to  the  ravages  of  disease.  Apart  from  the  physiological  benefits  of 
commensalism — now  becoming  more  generally  recognised — the 
more  or  less  complete  isolation  of  individual  species  that  occurs 
under  natural  conditions  is  itself  a  check  to  the  extension  of 
disease. 

' '  These'  facts  lead  up  to  the  consideration  of  what  I  look  upon 
as  by  far  the  most  important  part  of  my  subject,  that  of  isolation. 
I  have  been  impressed  with  a  sense  pf  the  immense  difficulties 
that  lie  in  the  way  of  combating  any  serious  insect  pests  where  no 
efficient  means  of  isolating  any  particular  area  for  purposes  of 
remedial  treatment  are  present.  What  are  the  conditions  that 
prevailed  during  the  reign  of  coffee  and  that  are  now  equally 
or  even  more  pronounced  during  the  age  of  tea  ?  We  find  vast 
continuous  tracts  of  land  planted  with  a  single  product,  unbroken 
by  either  natural  or  artificial  boundaries,  and  affording  no  hind- 
rance, to  the  free  distribution  of  any  infectious  disease.  Under 
such  conditions  how  can  we  hope  to  effectively  deal  with  our 
insect  enemies  ?  Vigorous  measures  may  be  employed  and  a 
pest  may  be  temporarily  exterminated  on  a  hmited  area,  but  the 
disinfected  parts  are  immediately  hable  to  fresh  invasions  from  all 
sides.  Given  an  isolated  field  we  can  deal  with  a  pest  with  some 
confidence  that  our  labour  will  not  be  nullified. 

' '  The  remedy  lies  in  the  formation  of  protective  belts  or  bound- 
aries of  either  jungle  or  cultivated  trees.  Such  belts  should  be  at 
least  30  feet  in  depth  and  composed  of  close-growing  trees  with  a 
good  cover  of  foliage.  As  in  most  trees  the  lower  parts  are  bare 
of  foHage,  a  separate  undergrowth  will  be  necessary  to  ensure  an 
effective  screen.  It  is  also  important  to  understand  that  the  trees 
and  shrubs  composing  the  belts  should  be  of  kinds  differing  as 
widely  as  possible  from  the  plants  that  are  to  be  protected  by  their 
means.     Insects,  though  seldom  dependent  upon  a  single  species 


PARA     RUBBER  485 

of  plant  for  their  nourishment,  generally  confine  their  attention  to 
distinct  groups  of  nearly  related  species  and  genera.  If  the 
protective  screens  are  composed  of  trees  belonging  to  a  distinct 
natural  order,  there  is  much  less  chance  of  the  inter-communi- 
cation of  pests. ' ' 

Block  Planting. 

It  is  not  necessary  to  apologise  for  such  a  lengthy  extract 
from  the  remarks  made  by  Mr.  E.  E.  Green,  as  the  subject  deserves 
more  consideration  than  it  has  yet  received  from  Eastern  officials 
and  planters.  In  order  to  meet  the  views  herein  expressed  several 
African  and  American  rubber  planting  companies,  dealing  with 
the  cultivation  of  several  species  in  the  same  territory,  have  caused 
the  trees  to  be  planted  in  blocks  so  that  the  continuous  area  under 
each  species  is  limited  and  the  trees  are  surrounded  by  unhke 
species.  This  block  system  of  planting  can  easily  be  carried  out 
when  the  estates  are  first  taken  over. 

When  touring  through  Ceylon  in  April,  1908;  the  writer 
observed  that  many  strips  or  patches  of  native  compounds,  planted 
with  species  other  than  those  yielding  rubber,  were  retained  ; 
these  serve  to  isolate  the  large  rubber  estates  in  the  same  district 
from  one  another,  and  their  preservation  should,  if  possible,  be 
encouraged. 

Diseases  of  Rubber  Plants. 

Much  has  been  written  on  the  subject  of  plant  diseases  in  the 
tropics,  and  Government  have  from  past  experience  seen  the 
necessity  to  appoint  officers  to  investigate  the  life  histories  of 
fungi,  insects  and  various  pests  as  soon  as  they  appear.  Every 
cultivated  plant  in  the  tropics  is  subject  to  the  attacks  of  injurious 
insects  and  fungi,  and  we  are  now  in  possession  of  up-to-date 
information  which  enables  planters  to  suppress  most  parasitic 
diseases  upon  their  appearance.  The  first  appearance  of  a  disease 
in  the  tropics  is  usually  promptly  notified  by  the  authorities, 
every  publicity  is  given  to  even  the  harmless  forms,  and  planters 
■  are  now  fully  alive  to  the  importance  of  carrying  out  well- 
advised  plant  sanitation  operations.  It  is  satisfactory  to  know 
that  effective  remedial  measures  can  be  applied  against  most  of 
the  diseases  known  to  affect  cultivated  rubber  plants. 

It  is,  however,  well  to  realize  that  trees  of  Hevea  brasiliensis, 
whether  growing  under  unhealthy  or  perfect  conditions,  are  not 
immune  from  the  attacks  of  parasitic  fungi  and  insects,  even  at  a 
time  when  the  number  and  age  of  the  host  plants  may  seem  to  be 
almost  negligible.  The  best  advice  which  can  be  given  is  to 
attack  all  diseases  in  their  earliest  stages  before  the  parasites 
have  increased  beyond  easy  control.  It  is  fortunate  that  among 
the  many  diseases  or  pests  mentioned  in  this  chapter  most  of  them 
are  not  of  a  very  serious  nature,  but  they  are  nevertheless  worthy 
of  full  consideration.  Only  the  more  important  are  dealt  with 
in  these  notes. 


486  PARA     RUBBER 

General  Principles  in   Plant  Sanitation. 

There  are  certain  general  principles  to  be  adopted  in  attacking 
diseases  on  cultivated  trees.  Briefly  they  can  be  enumerated  as 
follows  : — 

Diseases  and  pests  should  be  promptly  dealt  with. 

A  permanent  sanitary  gang  of  experienced  coolies  should  be 
set  apart  for  disease  work,  and  augmented  whenever  necessary, 
even  if  this  involves  reduction  of  working  coolies  on  other 
important  divisions  of  the  estate  work. 

Efficient  spra5dng  machines  should  be  kept  at  hand  and  always 
in  working  order.  As  Carruthers  pointed  out,  the  cost  of  even  the 
most  expensive  steam-power  spraying  apparatus,  one  capable 
of  reaching  the  tops  of  trees  80  feet  or  more  in  height,  bears  an 
infinitesimal  proportion  to  the  value  of  the  trees  on  even  a  small 
estate. 

A  stock  of  chemicals  for  spraying  should  always  be  at  hand, 
and  acquaintance  should  be  made  with  the  methods  of  using  the 
most  efficient  remedies. 

The  treatment  of  the  soil  after  the  removal  of  a  tree  having 
diseased  roots  is  not  in  practice  too  clearly  understood.  Liming 
can  only  have  an  indirect  effect,  as  by  neutralizing  soil  the  extreme 
acidity  of  which  has  been  responsible  for  the  encouragement  of 
the  disease.  The  use  of  one  of  the  proprietary  soil  fungicides 
may  be  recommended,  though  one  cannot  at  present  endorse 
the  claim  that  they  effect  a,  cure  in  situ  of  the  diseased  tree  itself. 

All  Fomes  areas  should  be  at  once  isolated  by  means  of 
trenches. 

All  diseased  tissues,  whether  in  the  orm  of  fruits  which  have 
fallen  from  the  trees,  cankered  bark  which  has  been  excised  by 
coolies,  branches,  prunings,  or  roots,  should  be  collected  and  burnt, 
either  on  the  spot  or  in  some  central  place. 

The  Removal  of  Stumps  and  Logs. 

The  question  of  removing  stumps  and  logs  always  receives, 
for  financial  reasons  especially,  careful  consideration.  It  does  not 
appear  as  a  rule  to  be  essential  in  Ceylon,  but  in  Malaya  it  is  generally  ■ 
necessary  as  a  preventative  of  root  disease  and  of  white  ants. 
It  is  a  question  which  the  proprietors  of  each  estate  must  decide 
for  themselves,  keeping  in  view  the  experience  of  estates  in  their 
districts.  A  very  convenient,  and  in  fact  the  best,  time  for 
removal  of  tree  stumps  and  logs  is  before  planting  out  ;  though 
the  objection  has  been  made  to  this  that  delay  in  planting  results, 
estate  operations  may  follow  a  course  with  regard  to  the  seasons 
that  render  this  objection  futile.  At  any  rate,  the  greater  expense 
of  removal  after  planting  must  be  considered  as  against  the  earher 
maturity  of  the  trees.  Where,  upon  the  older  planted  estates, 
the  wood  was  left  to  decay,  great  improvement  has  since  been 
made  in  many  cases  by  clearing  it  away.  The  cost  per  acre  has 
appeared  enormous,  but  it  has  amounted  to  much  less  than  the 
total  cost  of  supplying  and  maintaining,  which  would  otherwise 


PARA     RUBBER  487 

have  been  incurred.  Yet  it  has  been  said  that  the  great  expense 
some  imes  involved  in  clearing  all  logs  and  uprooting  stumps  is 
not  warranted,  since  their  removal  does  not  appreciably  decrease 
the  loss  of  trees  through  attacks  of  root  disease  and  white  ants. 

It  should  not  be  forgotten  that  weeding  is  better  and  more 
cheaply  done  on  estates  where  all  timber  has  been  removed  prior 
to  or  immediately  after  planting. 

Some   Precautions   in  Pruning. 

When  dead  or  diseased  twigs  and  branches  are  cut  away, 
care  should  be  taken  that  they  are  removed  flush  with  the  branches 
or  trunk,  so  that  the  bark  may  grow  over  the  wound.  Otherwise, 
as  foresters  have  found  out  by  experience,  the  bark  being  unable 
to  cover  the  exposed  area,  the  latter  is  very  liable  to  attack  by 
insects  and  fungi.  All  wounds  left  after  pruning  diseased  branches 
should,  if  possible,  be  protected.  Coal-tar  is  more  efficient  than 
wood-tar,  but  no  more  should  be  applied  than  is  essential,  in  view 
of  its  possible  poisoning  effects.  In  America  white-lead  paint  is 
sometimes  favoured  for  this  purpose,  but  information  is  not  to 
hand  of  its  applicability  in  the  tropics,  though  there  is  no  reason 
for  doubting  it.  Care  should  be  taken  to  prevent  the  coating 
materials  being  used  on  diseased  areas,  as,  if  the  latter  are  simply 
covered  with  tar,  the  destruction  will  ultimately  be  greater.  Where 
"cankered"  bark  is  being  treated,  the  operator  should  excise 
every  particle  of  diseased  tissue  before  allowing  the  area  to  be 
covered  with  tar  or  any  other  substance  ;  in  fact,  it  is  usually 
safer  to  allow  such  areas  to  heal  without  being  covered  with  any 
protective  substances. 

Spraying  Apparatus. 

Up  to  the  present  no  extensive  use  has  been  found  on  rubber 
plantations  for  powerful  spraying  machines ;  those  used  so  far 
apparently  having  been  sprayers  fitted  with  hand-pumps.  For 
fluids  or  washes  containing  insoluble  constituents,  an  up-to-date 
apparatus  is  necessary  in  which  efficient  stirring  is  brought  about. 
In  some  forms  of  apparatus,  as  in  the  Strawsonizer,  the  stream 
issuing  from  the  nozzle  is  broken  up  further  by  an  air-blast 
impinging  upon  it. 

Iron  vessels  should  not  be  used  when  copper  compounds  are 
being  sprayed.  Copper  sprayers  should  be  discarded  when 
ammoniacal  spraying  mixtures  are  used. 

The  sprayers  now  in  use  consist  of  (i)  hand  syringes,  (2) 
knapsack  sprayers  for  carrying  on  the  coolies'  backs,  and  (3) 
sprayers  requiring  considerable  power.  Some  of  these  can  be 
used  in  conjunction  with  the  spraying  of  weeds. 

Merryweather's  have  supplied  various  types  of  portable 
sprayers  to  estates.  The  simplest  type,  and  one  which  can  be 
recommended  for  work  on  a  small  scale,  consists  of  a  barrel 
constructed  of  oak,  with  a  capacity  of  36  gallons,     A  hand-pump 


488  PARA    RUBBER 

for  generating  pressure  is  supplied.  The  apparatus  is  mounted 
on  wheels  and  can  be  moved  about  and  worked  by  one  man. 

In  other  sprayers,  pumps  are  driven  by  oil  or  petrol  engines. 
In  one  type  the  apparatus  is  provided  with  a  horizontal  oil  engine, 
a  pump  of  the  "VaUent"  type,  and  4  to  6  spraying  jets.  In 
another  form,  a  vertical  petrol  engine  is  used  to  drive  the  pump, 
which  is  suitable  for  six  spraying  jets  and  for  working  up  to  a 
pressure  of  200  lb.  per  square  inch.  This  is  recommended  where 
pumping  has  to  be  carried  on  continuously  for  a  considerable 
period.  It  will  be  obvious  that  these  spraying  machines  can  be 
used  for  spraying  to  a  great  height  and  over  a  large  area. 

Hand  sprayers  and  syringes  are  sometimes  the  only  kinds 
which  can  be  used,  as  when  the  estates  are  steep  and  young  and 
badly  provided  with  roads.  Numerous  firms  supply  these  in 
various  types. 

Fungicides. 

All  fungicides  should  be  considered  as  poisons,  though  some 
are  so  only  in  a  small  degree.  Care  should  be  taken  to  guard 
against  any  corrosive  effects  upon  the  skin.  All  chemicals  should 
be  purchased  from  reliable  dealers  at  prices  that  will  command 
relative  purity  and  freedom  from  constituents  harmful  to  the 
trees. 

Copper  Sulphate. — The  cheaper  kinds  contain  iron  sulphate, 
which  is  in  strength  sometimes  sufficient  to  cause  damage.  Material 
with  a  purity  of  98  per  cent,  should  be  used.  This  salt  enters 
with  lime  into  the  composition  of  Bordeaux  mixture  ;  it  has  also 
been  employed  as  a  soil-dressing  for  root  disease. 

"Solubic  Brand"  sulphate  of  copper  (prepared  by  Messrs. 
Strawson),  is  guaranteed  not  less  than  99%  pure,  and  also  has  the 
advantage  of  being  in  fine  granular  form  which  is  instantly  soluble 
in  cold  water.  It  is  superior  to  ground  or  powdered  sulphate  of 
copper  as  it  is  more  quickly  soluble,  and  does  not  "cake."  It 
is  suited  for  use  on  rubber  plantations  for  destroying  weeds  as 
well  as  a  fungicide,  owing  to  its  solubihty,  guaranteed  purity,  and 
fine  form. 

Bordeaux  mixture. — The  constituents  of  this  mixture  'are  : 
copper  sulphate  (98  per  cent.),  6  lb.  ;  freshly-burnt  lime,  4  lb.  ; 
water,  45  gallons.  The  following  directions  for  making  up  the 
mixture  are  given  by  Strawson.  In  a  wooden  vessel  dissolve  the 
sulphate  in  half  of  the  water.  Slake  the  lime  to  a  uniform  mass, 
and  add  to  it  the  rest  of  the  water.  Pour  the  lime  mixture  into 
the  copper  solution,  stirring  well.  Upon  settling,  the  liquid  should 
not  be  tinged  with  blue.  The  mixture  may  be  bought  in  powder 
form,  already  prepared,  water  being  added  for  use.  Constant 
agitation  is  necessary  during  spraying.  The  most  useful  applica- 
tion of  this  mixture  is  as  a  preventative  of  pink  disease,  when  it  is 
used  as  a  wash  ;  it  can  be  applied  with  a  brush.  There  is  con- 
siderable difficulty  in  preparing  the  material  so  that  it  is  uniform 
and  neutral.  Moreover,  without  a  special  dehydrating  plant,  it 
is  impossible  to  concentrate  the  material. 


PARA     RUBBER  489 

Strawsonite  (the  original  ready-made  Bordeaux  mixture)  is 
highly  concentrated — that  is  to  say,  a  ton  of  Strawsonite  actually 
contains  the  same  amount  of  metallic  copper  as  a  ton  of  sulphate 
of  copper  itself.  Thus  i  ton  of  sulphate  of  copper  plus  J  ton  of 
lime  makes  approximately  only  i  ton  of  Strawsonite,  the  loss  in 
weight  being  caused  by  driving  off  moisture.  It  is  guaranteed  to 
contain  24  to  25  per  cent,  of  metallic  copper,  which  is,  of  course, 
the  same  percentage  of  copper  as  in  pure  sulphate  of  copper  itself. 
The  advantage  to  the  planter  in  using  Strawsonite  is  (i)  the 
material  is  uniform,  (2)  the  trouble  and  risk  of  mixing  is  avoided — 
merely  cold  water  has  to  be  added,  (3)  there  is  economy  in  freight, 
as  the  lime  is  already  included  in  the  compound. 

When  buying  ready-made  Bordeaux  mixtures  planters  should 
always  ask  for  the  strength  in  copper — some  mixtures  contain  only 
about- 5  to  10  per  cent,  of  copper. 

Lime-sulphur  wash. — This  mixture,  with  somewhat  similar 
uses  to  Bordeaux  mixture,  especially  as  a  preventative,  has  not 
received  much  notice  in  the  East.  Take  freshly-burnt  lime, 
7  lb.  ;  flower  of  sulphur,  3J  lb.  ;  common  salt,  3  lb.  ;  water  to 
make  10  gallons.  Boil  half  the  lime  with  the  whole  of  the  sulphur 
for  an  hour  in  3  gallons  of  the  water.  Slake  the  rest  of  the  lime, 
making  up  with  3  gallons  of  water,  and  add  the  salt.  Pour  the 
latter  mixture  into  the  first  and  add  the  rest  of  the  water.  This 
is  an  insecticide  (for  scale  insects,  etc.),  as  well  as  a  fungicide.  Its 
use  is  likely  to  extend,  but  at  present  one  cannot  recommend 
definite  strengths  for  use.  The  above  formula  is  that  for  a  winter- 
wash  in  the  temperate  zone  ;  probably  on  rubber  plantations  about 
100  per  cent,  more  water  will  prove  a  sufficient  strength  if  the  wash 
is  used  for  other  purposes  than  for  painting  the  bark. 

Carholineum  plantarium. — This  extract  of  wood-tar  has  been 
recommended  a?  a  dressing  in  root  diseases.  But  it  must  be 
noted  that  the  general  opinion  is  that  coal-tar  is  more  efficient 
than  wood-tar,  and  this  may  apply  as  well  to  the  extracts. 

Soil  fungicides.- — A  number  of  proprietary  articles  are  on  the 
market  for  soil  treatment  in  root  disease,  among  which  may  be 
mentioned,  "Furigal, "  "Clubicide, "  etc.  Lime  and  copper 
sulphate  are  also  used  for  forking  into  the  soil,  in  connection  with 
root  diseases. 

Insecticides 

The  constituents  of  insecticides  act  in  three  ways :  (i)  as 
stomachic  poisons  for  caterpillars,  beetles,  and  other  leaf  and 
wood-eating  insects  ;  (2)  as  corrosives,  for  plant-sucking  bugs,  as 
the  aphides  ;  and  (3)  as  asphyxiators,  for  white  ants,  and  also  for 
aphides.  The  stomachic  poisons  are  sprayed  on  to  the  trees,  dug 
into  the  soil,  or  bait  poisoned  with  them  is  put  down.  The 
corrosives  are  sprayed.  Asphyxiators  are  sometimes  sprayed  in 
the  form  of  oil  emulsions ;  occasionally  they  are  dug  into  the 
soil  as  powders,  which  give  rise  to  fumes,  or  the  fumes  may  be 
directly  applied. 


490  PARA     RUBBER 

Arsenate  of  lead. — This  is  a  compound  made  up  as  follows  : 
acetate  of  lead  (g8  per  cent.),  2f  oz.  ;  arsenate  of  soda  (98  per 
cent.),  I  oz  ;  water,  10  gallons.  The  chemicals  are  placed  in  the 
water  together  and  dissolved.  If  thought  desirable,  a  pound  of 
treacle  may  be  added  to  ensure  adhesion  to  the  foliage.  Arsenate 
of  lead  has  been  preferred  to  Paris  Green,  as  it  sticks  better,  and  is 
said  to  be  less  dangerous  to  the  foliage.  It  is  a  valuable  poison  for 
leaf-eating  insects. 

Arsenate  of  lead  can  be  prepared  on  the  plantation  by  the 
grower,  but  the  chemicals  are  highly  poisonous  and  are  dangerous 
to  handle.  Moreover,  home-made  preparations  frequently  contain 
a  high  percentage  of  arsenious  acid,  which  scorches  the  foliage. 

Arsenate  of  Lead  [Strawson  Swift). — This  is  the  original 
arsenate  of  lead  which  was  first  discovered  in  America.  It  is 
said  not  to  scorch  the  foliage,  and  is  so  intensely  adhesive  that  it 
will  remain  upon  the  foliage  for  many  weeks,  and  is  not  even 
washed  off  by  ordinary  rains.  It  is  in  a  fine  state  of  sub-division, 
and  does  not  clog  the  spraying  machine. 

Paris  Green. — This  is  arsenate  of  copper  and  is  a  powerful 
poison.  Being  insoluble  in  water,  the  mixture  must  be  well 
stirred  during  application.  A  standard  preparation  is  Blundell's 
Paris  Green,  which  is  supplied  as  a  powder  or  a  paste.  Take 
I  oz.  of  either  and  mix  in  10  gallons  of  water.  A  fine  spray  is 
necessary. 

Petroleum  emulsion. — This  is  the  most  useful  remedy  for 
plant-sucking  bugs,  which,  of  course,  cannot  be  attacked  by 
poisons  sprayed  upon  their  food  material.  The  constituents  of 
a  typical  formula  are  :  petroleum,  2  gallons  ;  water,  i  gallon  ; 
soft  soap,  I  lb.  Add  the  soap  to  the  water  and  bring  to  the 
boil,  dissolving  thoroughly.  Into  the  solution,  when  boiling 
hot,  stir  the  petroleum.  Immediately  well  churn  the  whole  to 
emulsify  ;  then  allow  to  cool,  when  a  jelly  should  form.  Use 
I  part  of  this  to  10  parts  of  water.  Spraying  should  take  place 
only  in  the  evening,  and  in  as  dry  weather  as  possible. 

Sulphur. — This  is  sometimes  useful  for  blights  on  nursery 
plants.  ' '  Flower  of  Sulphur ' '  can  be  distributed  as  a  fine  powder 
by  means  of  a  hand-blower  or  in  a  bag  made  of  coarse  cloth. 

Soil  Insecticides. — A  proprietary  article  for  forking  into  the 
soil  is  ' '  Vaporite, ' '  a  preparation  of  naphthalin  and  tank-waste 
from  alkali  manufacture  that  liberates  a  poisonous  gas  in  the  soil. 
The  manure  ' '  Kainit ' '  has  been  recommended  for  the  treatment 
of  tender-skinned  beetle  grubs.     Quicklime  has  a  similar  action. 

Burrs,  Twists  and  Fasciations. 

Unusual  growths,  which  cannot  be  associated  with  any 
disease,  often  appear  on  healthy  Hevea  trees.  On  the  trunk  two 
types  of  burrs  (Circ.  R.B.G.,  Vol.  IV.,  and  Straits  Bull.,  June, 
191 1),  may  occur  within  the  tapping  area.  One  type  is  due  to 
abnormal  thickening  or  upraising  of  wood  below  the  tapping  lines 
or  below  spots  through  which  the  teeth  of  prickers  have  passed. 


PARA     RUBBER  491 

In  such  cases  the  cambium  is  injured  and  an  excessive  quantity 
of  woody  tissue  produced.  The  second  type  consists  of  woody 
nodules  in  the  cortex,  each  with  its  own  cambium  or  growing 
tissue  ;  these  are  at  first  isolated  in  the  bark,  but  later  become 
connected  with  the  wood.  The  nodules  betray  their  existence 
by  raising  the  surface  of  the  bark.  Eventually  they  develop 
each  into  a  larger  burr,  or  a  number  may  fuse  together. 

Tapping  over  burrs  cannot  be  recommended.  It  is  better  to 
allow  these  to  work  themselves  out,  especially  if  they  are  in  the 
form  of  small  nodules. 

Cases  of  twisted  stems  in  seedlings  are  frequent ;  the  cause 
is  usually  the  position  of  the  seeds  in  planting.  The  best  position 
is  perhaps  the  horizontal  one  with  the  flattened  end  upwards. 
When  planted  vertically  with  the  more  pointed  (micropylar)  end 
uppermost,  a  high  percentage  of  abnormal  seedlings  develop. 

Sometimes  the  trees  are  irregular  in  outline  in  consequence 
of  having  been  exposed  to  wind,  the  surface  facing  the  wind 
frequently  being  flattened  ;  such  trees  when  twisted  are  not  as 
easy  to  tap  as  those  with  normal  stems. 

Fasciated  stems  have  also  been  recorded  ;  they  are  rare,  and 
do  not  appear  to  be  due  to  parasitic  fungi  or  insects. 

Seed    Pests. 

There  are  no  records  of  diseases  of  seeds  due  to  fungi,  nor 
are  there  any  showing  that  seeds  may  carry  the  germs  of  diseases 
that  may  attack  living  plants.  It  is  noteworthy  that  the  Governor 
of  Cochin-China,  to  protect  against  all  possible  danger  of  this 
kind,  has  ordered  that  all  introduced  Hevea  seeds  be  immersed 
for  half-an-hour  in  a  solution  of  o-i  per  cent,  corrosive  sublimate 
or  I  per  cent,  sulphate  of  copper.  He  has  interdicted  the  in- 
troduction of  the  plants. 

Craw  found  that  a  consignment  of  seeds  sent  to  Hawaii  from 
Ceylon  were  infected  by  mites.  The  seeds  were  treated  successfully 
with  carbon  bisulphide. 

Nursery  Plants  and  Stumps. 

Fungi. — A  thread  blight — Pestalozzia  ■palmarum — the  cause 
also  of  grey  blight  of  tea  and  of  leaf  disease  in  the  coconut,  has 
been  found  on  the  green  stems  and  leaves  of  nursery  seedlings.  The 
fungus  forms  irregular,  white  areas  spreading  generally  from  the 
tip  of  the  leaf,  or  it  forms  similar  areas  at  the  base  of  the  stem,  when 
it  kills  the  seedling.  All  the  plants  attacked  should  be  removed, 
and  the  soil  disinfected  with,  say,  carbolic  acid  one  part  to  160  of 
water. 

A  leaf  disease  has  appeared  among  seedlings  in  Surinam 
which  produces  irregular  brown  areas,  with  yellowish-green  zones 
outside,  upon  the  upper  surfaces  of  the  leaves.  The  disease  has 
not  so  far  been  amenable  to  treatment,  but  it  is  not  a  serious  one. 

The  fungus  responsible  for  the  final  stage  of  dieback — 
Botryodiflodia    theobromae — mentioned    in    the    section    of    this 


492  PARA     RUBBER 

chapter  dealing  with  stem  diseases — may  attack  stumps.  The 
infection  appears  to  arise  from  the  soil  in  which  the  trees  are 
planted.  Liming,  after  pulling  out  the  diseased  plants,  may- 
be tried,  though  it  is  not  in  all  cases  efficient. 

In  the  Straits,  the  leaves  of  seedHngs  have  been  attacked 
by  a  fungus  (Straits  Bull.,  July,  1905),  regarding  which  Massie 
reported  :  ' '  The  pale  blotches  on  the  leaves  are  caused  by  some 
species  of  Cercospora,  but  the  absence  of  fruit  prevents  specific 
identification."  Ridley  stated  that  this  fungus,  was  common 
all  over  the  Malay  Peninsula,  but  that  except  in  the  case  of  seedlings 
not  much  harm  is  done.  It  has  been  suggested  that  this  fungus 
may  be  a  species  of  Helminthosporium. 

Leaves  of  Hevea  seedhngs  have  been  attacked  by  a  species 
of  Helminthosporium.  The  leaves  (T.A.,  June,  1905),  were 
studded  with  circular,  white,  semi-transparent  spots,  each  sur- 
rounded by  a  brown  cushion  from  which  arose  the  threads  of  the 
fungus  This  disease  is  one  which  leads  to  partial  defoliation 
and  checks  the  growth  of  the  young  plants.  In  all  such  cases  the 
diseased  leaves  should  be  pulled  off  and  burnt,  and  the  rest  of  the 
plants  sprayed  with  Bordeaux  mixture. 

Insect  Pests. — ' '  Mites ' '  in  rubber  nurseries  have  been  reported 
from  the  Straits.  Arden  (Straits  Bull.,  June,  1905),  stated  that 
in  some  cases  the  young  leaves  fall  from  the  plant  before  they 
are  fully  developed,  and  in  other  cases  the  mature  leaves  present 
a  crinkled  appearance,  are  yellowish-green  in  colour,  and  appear 
to  be  dotted  with  numerous  punctures.  He  compared  it  to 
' '  Red  Spider, ' '  and  believed  that  the  disease  was  mainly  limited 
to  plants  growing  under  unfavourable  conditions. 

Bernard  (Bull.  Dept.  Agric,  Indes  Neerlandaises,  No.  6) 
records  the  attacks  of  mites  on  the  leaves  of  nursery  plants  in 
Java.  He  recommends  destroying  the  leaves,  or  as  an  alternative 
the  use  of  insecticides. 

Green  has  the  following  notes  (TA.,  Feb.,  1906),  regarding 
pests  which  are  associated  with  stems  of  young  plants  : — 

"The  cut  ends  of  young  Hevea  stumps  are  frequently  tun- 
nelled by  various  small  species  of  bees  and  wasps.  But  these 
insects  are  not  responsible  for  the  dying  back.  The  pith  of  any 
dead  stem  would  be  utilized  in  a  similar  manner.  When  a  young 
Hevea  plant  is  stumped,  it  usually  dies  back  to  the  node,  and  it 
is  in  such  dried  ends  that  the  tiny  wasps  construct  their  nests. 
They  cannot  be  regarded  as  pests,  but  more  properly  as  friends, 
for  most  of  them  provision  their  nests  with  Aphides  taken  from 
some  other  plants. ' ' 

The  deserted  tunnels  of  these  wasps  and  bees  are  sometimes 
tenanted  by  a  species  of  thrips,  but  the  latter  is  quite  harmless^ 

The  grub  of  the  large  cockchafer — Lepidiota  pinguis — appears 
to  be  troublesome  on  young  Hevea  plants  ;  Green  reports  over 
3,000  plants  being  killed  in  a  single  clearing.  In  some  cases  the 
tap-root  has  been  eaten  through.  If  ' '  Kainit "  or  "  Vaporite ' ' 
are  forked  in  within  the  areas  affected,  the  grubs  can  be  destroyed. 


PARA     RUBBER  493 

As  the  effects  of  their  attack  upon  the  plants  appear  only  after 
the  damage  is  irremediable,  preventative  measures  against  further 
attacks  alone  are  possible. 

Green  (T.A  ,  Feb.,  1906),  makes  the  following  remarks  about 
a  beetle  pest  : — 

' '  Specimens  of  a  small  Longicorn  beetle,  said  to  be  responsible 
for  the  death  of  young  Hevea  trees,  have  been  received  from 
Southern  India.  The  insect  proved  to  be  Pterolophia  annulata, 
a  species  that  occurs  in  Ceylon  also.  I  have  no  records  of  injury 
done  by  this  insect  to  Hevea  in  this  country,  but  I  have  bred  out 
a  specimen  from  the  diseased  bark  of  a  Ceara  rubber  tree.  My 
correspondent  from  India  reports  that  the  beetles  girdle  the 
stems,  the  upper  parts  of  the  trees  dying  back  down  to  the  injured 
area.  This  girdling  habit  is  common  to  many  species  of  Longicorn 
beetles  The  object  of  the  manoeuvre  is  believed  to  be  to  check 
the  sap  and  induce  the  degree  of  decay  best  suited  to  the  nourish- 
ment of  the  grubs  of  the  beetle,  the  eggs  having  first  been  inserted 
in  the  back  above  the  point  of  injury.  If  this  pest  should  become 
common,  it  might  cause  serious  damage  on  rubber  plantations. 
In  case  of  any  occurrence  of  the  pest  the  stems  of  all  the  trees 
should  be  carefully  searched.  The  adult  beetles  will  probably 
be  found  clinging  to  the  bark  of  the  trees,  when  they  can  be  easily 
captured  and  destroyed. ' ' 

Specimens  of  another  Longicorn  beetle — Moechotypa  verruci- 
collis — said  to  have  killed  young  rubber  stumps,  have  been  reported 
upon  by  Green  (Circ.  R.B.G.,  Ceylon,  No.  12,  vol.  IV.).  The 
bark  of  the  injured  plahts  had  been  nibbled  off,  and  the  bare  wood 
exposed.  The  probability  is  that  the  attacked  plants  were  first 
diseased,  as  the  beetles  cannot  deal  with  latex-yielding  living 
tissues.  Examination  of  the  roots  proved  that  they  had  pre- 
viously been  attacked  by  the  parasitic  fungus,  Botryodiflodia 
elastica.     Hand  picking  is  suggested. 

A  few  cases  of  damage  to  young  plants  by  cut-worms — larvae 
of  Agrotis  segretis — have  been  recorded.  Injury  can  be  prevented 
by  adding  ' '  Vaporite ' '  before  putting  in  the  seed. 

Dragon-flies  have  in  error  been  blamed  for  causing  injury, 
but  as  they  are  insectivorous  they  should  be  regarded  rather  as 
beneficial. 

The  ' '  black  bug ' ' — Lecanium  nigrum— where  it  occurs 
thickly  on  young  plants,  checks  their  growth,  but,  according  to 
one  authority  (Journ.  Econ.  Biol.,  May,  1911),  does  little  or  no 
harm  to  well-established  plants.  It  affects  leaves  of  young  stems. 
Where  destruction  by  hand  is  too  laborious  a  method  to  adopt, 
one  of  the  standard  soapy  insecticides  may  be  applied.  Other 
species  of  scale-bug  seem  to  be  of  no  serious  importance 

According  to  Green  (Circ.  R.B.G.,  No.  12,  vol.  IV.),  the 
leaves  of  Hevea  seedlings  are  reported  to  have  been  punctured 
by  certain  plant-sucking  bugs,  Leptocorisa  acuta  and  Callicratides 
rama.  The  former  is  known  as  the  "Rice-sapper."  The  bugs 
can  puncture  soft  parts  of  the  stem,  causing  the  terminal  shoot  to 


494  PARA     RUBBER 

wilt  and  droop  Damage  from  this  cause  can  be  prevented  by 
lightly  sweeping  a  butterfly  net  over  the  growing  seedlings  and 
destroying  the  insects  by  hand. 

Crickets  have  been  described  by  Ridley  (Straits  Bull.,  March, 
1906),  as  biting  off  the  tips  of  rubber  seedlings,  and  Waterhouse  of 
the  British  Museum  has  identified  some  of  these  pests  as  Brachy- 
irypes  achatina  and  Gymmogryllus  elegans. 

The  mole-cricket  has  been  blamed  for  eating  off  the  young 
shoots  of  stumps.  The  planter  complaining  has  tried  liming, 
tarring,  and  even  bird-liming  without  avail,  and  he  has  been 
told  that  all  that  can  be  done  is  to  pull  up  the  stumps  and  supply 
others  of  greater  height.  I  have  known  of  large  acreages  destroyed 
by  this  pest. 

Spotted  locusts  have  been  reported  to  occasionally  damage 
young  dadap  and  rubber  plants  in  Ceylon  and  the  Straits,  but  they 
usually  ignore  Hevea  trees. 

Wingless  locusts  reported  from  various  districts  in  Ceylon  are 
said  to  destroy  the  seedlings,  the  bark  being  gnarled  and  com- 
pletely eaten  off  in  parts.  Poisoned  baits  have  been  found 
effective  in  such  cases  (T.A.,  Nov.,  1905),  one  of  the  best  being 
"  arsenic-salt-horsedung "  mixture,  made  by  compounding  one 
part  of  Paris  green  or  white  arsenic  with  two  parts  of  salt  and 
forty  parts  fresh  horsedung.  It  is  recommended  that  this  should 
be  broadcasted  among  the  affected  plants  or  wherever  the  locusts 
may  be  noticed. 

Several  smaller  species  of  grasshopper  sometimes  defoliate 
the  young  nursery  plants.  The  same  poisonous  mixture  should  be 
used. 

A  species  of  white  ant — Termes  carbonarius — previously 
thought  to  be  harmless,  has  been  found  stripping  newly-planted 
stumps  (Straits  Bull.,  Aug.,  1911),  by  eating  the  bark,  over  which 
it  constructs  galleries.  The  nests  are  in  large  mounds  often 
six  feet  high.  Treatment  of  their  nests  is  by  the  fumigation 
method  described  later  for  use  against  Termes  gestroi. 

Leaf  Diseases  and  Pests. 
There  are  already  several  insects  and  fungi  which  live  on  the 
leaves  of  Hevea  trees,  but  none  of  them  are  very  harmful.  To  a  very 
hmited  extent  the  annual  fall  of  leaf  that  takes  place  on  rubber 
trees  after  they  have  passed  their  third  year  is  an  advantage 
when  dealing  with  leaf  pests,  as  the  foliage  can  be  easily  and 
regularly  collected  and  burned.  Again,  the  leaves  may  happen 
to  fall  prior  to  the  formation  of  the  spore-producing  bodies,  and  in 
this  way  assist,  to  some  extent,  in  checking  the  spread  of  disease. 
But  it  should  be  remembered  that  Hevea  trees  are  in  possession 
of  their  foliage  for  about  50  weeks  each  year,  and  to  assume  that 
the  leaves,  owing  to  the  deciduous  character  of  the  tree,  are  not 
likely  to  contract  a  permanent  disease  is  by  no  means  sound. 
Further,  the  trees  do  not  pass  through  their  leafless  period  all  at  the 
same  time,  so  that  there  are  at  all  times  some  trees  in  leaf  to  per- 
petuate disease. 


PARA     RUBBER  495 

Fungi. — A  thread-blight  (Straits  Bull.,  April,  1911),  attacks 
the  leaves  and  younger  twigs  of  trees  in  Malaya.  Bancroft 
found  white  strands  which  may  mat  the  leaves  together  in  dense 
masses.  As  the  disease  progresses,  the  leaves  fall,  and  the  younger 
twigs  wither.  Infection  is  by  contact,  say  by  a  fallen  leaf  infested 
with  the  disease  being  blown  against  a  healthy  leaf  or  a  branch,  or 
by  the  touching  of  branches  of  adjacent  trees.  All  the  fallen 
leaves  and  twigs  under  affected  trees  should  be  gathered  into  heaps 
and  burnt.  The  trees  should  be  pruned,  the  prunings  being  also 
burnt.  Spraying  with  lime-sulphur  wash  will  probably  help  to 
keep  the  disease  in  check. 

Insects. — A  species  of  weevil,  allied  to  if  not  identical  with 
Astacus  lateralis  (Wray,  Perak  Museum  Notes,  1897),  was  reported 
in  the  Straits  to  eat  Hevea  leaves.  Pratt  received  from  Malayan 
estates  some  specimens  of  a  weevil — Eumeces  squamosus — that 
injures  the  young  trees  by  eating  the  leaves  and  younger  shoots. 
Two  species  of  weevil  eating  the  leaves  have  been  recorded  from 
Java.     For  these,  hand-picking  is  the  only  remedy. 

A  new  species  of  scale-bug  upon  the  leaves,  belonging  to  the 
genus  Mytilaspis,  has  been  recorded  (T.A.,  Dec,  1905),  but  it  is 
unlikely  to  cause  any  serious  trouble. 

According  to  Green,  there  is  no  single  species  of  caterpillar 
that  has  a  preference  for  the  foliage  of  Hevea.  But  every  cater- 
pillar found  actually  feeding  upon  the  plant  must  be  treated  as  a 
potential  enemy  and  destroyed. 

Specimens  of  the  "pigmy  rose  beetle" — Cingala  tenella — 
were  submitted  to  Green  with  leaves  showing  nurnerous  small 
irregular  perforations.  The  insects  were  dead  on  arrival,  and 
were  firmly  glued  to  the  leaves  by  coagulated  latex. 

Fruit  Disease. 

Planters  in  many  parts  of  Ceylon  have  occasionally  been 
alarmed  at  the  curious  behaviour  of  certain  fruits  ;  some  dry 
up  and  remain  attached  to  the  twigs,  and  others  of  all  ages  fall  to 
the  ground  without  expelling  the  seeds.  The  fall  of  the  unex- 
ploded  fruits  is  often  due  to  disease.  The  disease  is  the  same 
— Phytophthora  Faberi — as  that  responsible  for  the  canker  of 
cacao  fruits,  and,  therefore,  affects  the  cultivation  of  both  Hevea 
and  cacao  trees.  This  disease  can  be  considered  when  dealing  with 
the  same  disease  on  the  stems. 

The  most  effective  way  of  fighting  the  fruit  disease  is  to  collect 
all  dried  fruits  which  are  on  the  trees  and  those  which  have  fallen 
to  the  ground  and  burn  the  lot  on  the  spot.  On  the  average  rubber 
estate  there  can  be  no  real  objection  to  burning  such  small  quantities 
of  fruits  as  this  treatment  involves. 

Stem     Diseases. 

Canker  of  the  stem  and  of  the  fruits  of  Hevea  (Circ.  R.G.B.,  No. 
13,  Vol.  v.),  is  caused  by  the  same  fungus — Phytophthora  Faberi — 
that  is  responsible  for  cacao  canker  and  fruit  disease.     On  young 


496  PARA     RUBBER 

trees  the  affected  bark  may  appear  darker  ;  in  some  cases  the 
bark  exudes  a  reddish  or  purplish  Uquid.  In  many  cases  the 
disease  has  been  discovered  only  when  the  tree  has  ceased  to  yield 
latex.  A  black  layer  is  found  beneath  the  outer  brown  bark, 
and  below  it  again  the  laticiferous  tissue  is  discoloured,  at  first 
being  greyish  with  a  black  border,  later  claret-coloured  brown  or 
yellow  on  green  pods,  and  black  on  dark-red  pods.  If  the  diseased 
pods  are  left  on  the  tree,  the  fungus  travels  down  the  stalks  into 
the  branches.  The  disease  is  usually  discovered  by  the  cessation 
of  the  latex  flow.  Sometimes  all  the  cuts,  sometimes  one  or  two 
only,  yield  no  latex  when  tapped.  In  some  cases  the  tapping  has 
struck  a  patch  of  canker  where  the  bark  is  clearly  diseased  ;  but 
in  other  cases  the  tapped  bark  appears  quite  healthy,  though  rather 
dry  and  slightly  yellowish.  In  other  cases  the  disease  occurs 
at  the  base  of  the  stem,  and  all  the  cuts  are  dry.  On  plantations 
of  Hevea  only,  canker  has  not  caused  very  much  damage,  but 
on  mixed  Hevea  and  cacao  plantations  it  may  be  more  serious. 

It  is  remarked  that  ' '  excision  of  diseased  tissues  is  the  re- 
cognised treatment  for  stem  canker.  All  the  discoloured  tissue 
should  be  cut  out  and  burnt.  The  difficulty  here  is  the  discovery 
of  the  canker  before  it  has  progressed  so  far  that  a  large  area  has 
to  be  excised.  The  tapping  coolies  should  be  shown  what  cankered 
bark  is  like,  and  they  should  be  instructed  to  stop  tapping,  and 
report  any  trees  which  cease  to  yield  latex,  even  if  the  flow  ceases 
only  on  one  cut. 

' '  If  the  wounds  caused  by  excision  of  cankered  bark  are 
small,  cow  dung  and  clay  is  the  best  covering  that  can  be  used 
to  promote  the  healing  process.  But  where  they  are  large,  so 
that  the  bark  cannot  be  expected  to  grow  over  them,  the  exposed 
wood  must  be  protected.  If  it  is  left  unprotected,  it  is  soon 
riddled  by  boring  beetles  which  rapidly  bring  about  the  destruction 
of  the  tree."  Fetch  suggests  that  the  exposed  wood  be  tarred, 
except  for  a  strip  of  an  inch  all  round,  and  that  this  strip  be  treated 
with  cow  dung  and  clay  as  before.  On  badly-affected  estates 
it  may  be  advisable  to  spray  all  the  stems  with  Bordeaux  mixture 
in  dry  weather  ;  this  treatment  would  kill  the  spores  and  thus 
assist  in  controlling  the  spread  of  the  disease. 

Pink  disease. — In  Java,  Ceylon,  South  India,  Medaya  and 
in  the  West  Indies,  "pink  disease,"  the  "djamoer  oepas"  of 
Java,  due  to  Corticum  javanicuni,  occurs.  In  addition  to  Hevea 
it  attacks  tea,  coffee,  cacao,  coca,  cinchona,  dadaps,  crotalaxia, 
etc.  The  spores  are  carried  by  the  wind,  evidently  to  some  large 
extent  from  the  jungle,  and  find  favourable  conditions  for  their 
development  upon  wet  bark.  In  South  India,  the  south-west 
monsoon  period  is  the  time  when  the  disease  begins  to  develop  ; 
its  growth  is  suspended  in  the  dry  season.  Close-planting  en- 
courages it.  It  generally  begins  at  the  fork  of  a  tree,  or  where 
several  branches  arise  close  together,  these  being  situations  where 
rain-water   collects.     At   first   a  superficial   pink   incrustation   is 


PARA     RUBBER  497 

formed,  and  as  it  spreads  over  the  surface  there  is  also  an  ex- 
tension into  the  bark,  which  it  kills.  This  splits  along  lines  at 
right-angles  to  one  another,  and  begins  to  peel  from  the  wood. 
Older  patches  lose  their  pink  colour,  becoming  yellow  and  even 
white.  According  to  Anstead,  treatment  by  cutting  out  the 
diseased  bark  and  painting  the  wound  with  Bordeaux  mixture  or 
tar  is  a  failure.  Affected  branches  should  be  cut  off  at  least  18 
inches  below  the  point  of  attack.  Where  the  trunk  is  affected, 
unless  3  feet  of  tappable  stem  can  be  left,  it  is  best  to  cut  the  tree 
down  to  the  ground  and  get  a  sucker  from  below  to  replace  it. 
The  knives  and  chisels,  and  also  the  coolies'  hands,  should  be 
washed  in  permanganate  of  potash  when  proceeding  from  tree  to 
tree. 

Gudgeon  used  Bordeaux  mixture  on  Palapilly  estate.  South 
India,  to  kill  the  alighting  spores.  Gum  was  added  to  make  it 
stick  on  the  trees.  The  mixture  was  applied  to  all  wounds  and 
points  of  attachment  of  branches  to  the  main  stem,  the  applica- 
tion being  made  before  the  beginning  of  the  south-west  monsoon. 
He  reported  (Planters'  Chronicle,  May,  1911),  that : 

"It  has  cost  me  about  150  rupees  to  do  500  acres,  200  acres 
af  which  were  2|-year-old  trees  and  cost  very  little.  This  includes 
labour,  pan,  copper  sulphate  and  brushes.  The  amount  a  coolie 
will  do  is  difficult  to  say,  as  it  entirely  depends  on  the  age  and 
size  of  the  trees  ;  I  also  pruned  the  trees  carefully  as  I  went 
along,  which  is  not  included  in  the  above  cost.  At  least  90  per 
cent,  of  the  trees  were  done  in  the  older  clearings ;  only  those  that 
had  branches  shooting  out  very  high  up  were  missed. ' ' 

Dieback.— The  essential  fungus — Botryodiplodia  theobromee — 
causing  "dieback"  of  the  Hevea  rubber  tree  and  cacao  (Dept. 
of  Agric.  F.M.S.  Bull.,  No.  9,  and  Circ.  R.B.G  .,  Ceylon,  No.  23, 
Vol.  IV.),  is  distributed  throughout  almost  the  whole  tropical 
zone,  though  as  a  disease  of  the  rubber  tree  it  is  reported  only 
from  Ceylon,  South  India,  and  the  Federated  Malay  States. 
Many  other  plants — tea,  coffee,  coconuts,  camphor,  tapioca, 
Albizzia,  etc.,  upon  which  it  is  found,  are  mostly  infected  only 
upon  parts  already  dead.  The  fungus  attacks  the  branches 
of  Hevea  at  a  point  some  distance  from  the  apex.  Death  of  the 
terminal  portion  follows  owing  to  interruption  of  the  food  supplies, 
and  the  disease  spreads  downwards,  in  some  cases  even  to  the 
roots.  Growth  is  very  rapid,  and  many  cases  are  mentioned 
where  a  tree  has  died  in  a  month  or  six  weeks  after  the  death  of 
the  uppermost  branches,  while  there  has  been  a  case  where  a 
2j-year-old  tree  was  killed  down  to  4  inches  from  the  ground  in 
twelve  days.  Both  wood  and  bark  are  discoloured,  becoming 
grey.  The  cambium  forms  a  black  or  dark  brown  film  which 
subsequently  dries.  The  fungus  spreads  mostly  through  the 
wood,  and  hyphae  extend  for  a  distance  of  4  or  5  inches  beyond  the 
discoloured  part  of  the  wood.  Where  the  growth  of  the  fungus 
is  slow,  and  the  infection  has  been  upon  an  older  part,  a  cankered 
appearance    arises.     In    Malayan   experiments   to   infect    Hevea 

FF 


498  PARA     RUBBER 

plants  with  the  spores,  it  was  found  that  infection  was  not  possible 
upon  an  uninjured  surface,  nor  at  a  shallow  wound  or  carefully 
tapped  surface,  but  it  resulted  in  every  case  where  wounds  were 
deep  enough  to  expose  the  wood. 

Though  the  fungus  Glceosporium  alborubrum,  said  in  Ceylon  to 
prepare  the  branches  for  the  attack  of  ' '  dieback, ' '  has  not  been 
observed  in  Malaya,  its  characteristics  must  be  noted.  It  appears 
on  the  branches  away  from  the  tip,  and  they  become  dark  brown, 
later  grey,  a  discolouration  that  extends  towards  the  tip  and 
towards  the  main  stem.  Fructifications  develop  that  cause 
very  minute  swellings  of  the  epidermis,  which  burst  at  the  top 
to  hberate  the  pink  or  white  spores,  the  minute  holes  remaining 
giving  the  surface  a  rough  appearance. 

The  most  familiar  fructifications  df  the  essential  "dieback" 
fungus — Botryodiplodia — are  situated  in  the  bark,  and  are  small 
black  spores  about  one  hundredth  of  an  inch  in  diameter,  a  size 
within  the  range  of  visibility.  These  spores  frequently  occur 
close  together,  and  united  into  a  continuous  mass,  whidh  happens 
especially  when  they  develop  in  cracks  in  the  bark  ;  in  such 
cases  they  may  form  a  projecting,  swollen  cushion.  When  ex- 
truded, the  spores  cover  the  surface  of  the  bark  with  a  fine  black 
powder.  This  fungus  has  been  variously  named  Diplodia  rapax, 
Lasiodiplodia  theohromce,  Botryodiplodia  elasticce,  etc.,  but  recent 
work  by  Bancroft  in  determining  a  certain  form  of  its  fructifica- 
tion other  than  the  above — there  are  three  forms  in  all — suggest 
that  the  name  in  the  future  must  be  given  as  Thyridaria  tarda. 
In  addition  to  thorough  sanitation  and  good  cultivation  as  general 
measures,  pruning  of  the  diseased  parts  is,  of  course,  necessary. 
The  cut  should  be  sloping  ;  it  should  be  tarred  and  all  excised 
parts  burnt.  A  useful  precautionary  measure  is  to  cut  off  all  dead 
green  shoots. 

It  should  be  noted  that  Ridley  denies  that  the  above  fungus 
attacks  living  tisues.' 

A  canker-like  disease — due  to  a  species  of  Fusicladium,  and 
yielding  to  similar  methods  of  treatment — is  recorded  from  Java 
by  Bernard. 

White  Ants. 

Insects. — The  termite  or  so-called  "white  ant" — Termes 
gestroi — which  enters  the  root  and  may  also  excavate  the  stem, 
is  a  most  troublesome  pest,  especially  in  the  Federated  Malay 
States.  At  one  time  stress  was  laid  upon  the  association  between 
white  ants  and  root  fungus,  the  ants  following  the  latter  ;  but 
Pratt  states  that  there  can  be  no  doubt  whatever  that  in  the  case 
of  at  least  90  per  cent,  of  the  trees  attacked,  the  white  ant  is 
solely  responsible. 

The  members  of  a  colony  consist  of  a  queen,  fertile  males, 
soldiers  and  workers.  The  queen  estabhshes  the  nest,  and  rears 
her  first  brood  of  workers  and  soldiers  until  they  are  capable  of 
undertaking  the  duties  of  the  colony.  After  this  she  becomes 
merely  an  egg-laying  machine— the  queen  of  another  species  of 


PARA     RUBBER  499 

termite  lays  at  the  rate  of  60  eggs  per  minute  or  more  than  80,000 
per  day — and  the  workers,  probably  with  the  assistance  in  part  of 
the  soldiers,  attend  to  her  needs,  care  for  the  young,  contmue 
the  building  of  the  nest,  and  excavate  the  burrows  through  the 
soil.  These  burrows  lie  from  six  inches  to  three  or  even  four  feet 
below  the  surface,  according  to  the  character  of  the  soil  and  the 
depth  of  the  soil-water.  They  may  be  of  great  lengths,  and  have 
been  traced  to  a  distance  of  300  feet  from  the  nest.  New  nests 
may  be  started  along  the  burrows  Nests  may  actually  be  found 
in  hollow  Hevea  trunks. 

The  sources  of  danger  are  decaying  jungle  stumps  and  logs. 
These  serve  not  only  for  harbouring  the  pests,  but  also  for  supplying 
food  in  the  form  of  finely-divided  particles  of  wood,  and  probably 
also  of  the  moulds  present.  Entry  to  the  Hevea  trees  may  be 
by  way  of  the  lateral  roots,  though  occasionally  the  burrow  goes 
straight  to  the  tap  root.  The  destruction  of  the  roots  and  the 
hollowing  of  the  stem  may  not  be  evident  for  some  time  The 
ravages  of  this  pest  often  leads  to  unsightly  excavations  and 
to  removal  of  soil  from  the  main  roots  near  the  stem. 

Upon  comparatively  new  estates,  where  dead  wood  in  various 
forms  may  be  found  in  abundance,  the  insects  thus  readily  find 
conditions  that  lead  to  their  rapid  increase  in  numbers.  At  the 
same  time  they  are  using  up  the  available  wood,  which  is  also 
disappearing  by  process  of  decay.  As  a  result  of  the  disappearance 
of  the  food  supply  there  is  a  much  greater  tendency  for  the  rubber 
trees  to  be  attacked,  and  the  hollow  stems  of  these  contain  nests 
in  great  numbers,  which  serve  as  new  centres  of  distribution.  The 
importance  of  dealing  promptly  with  the  pest  is  clear. 

White  Ants  and  Rubber  Exudations. 

A  fanciful  and  erroneous  idea  has,  in  India,  obtained  a  footing 
that  Termes  Gestroi  ' '  attacks  the  tree  for  the  purpose  of  obtaining, 
rubber  from  it,  for,  on  applying  pressure  to  the  bodies  of  the 
termites,  it  was  found  that  the  majority  of  them  were  full  of 
fresh  latex.  They  apparently  collect  and  store  the  rubber,  masses 
of  rubber  being  found  as  a  rule  in  the  nests,  which  are  usually 
situated  at  the  crown  of  the  root.  From  one  of  these  nests  situated 
at  the  base  of  a  three-foot  girth  tree  as  much  as  2  lb.  of  rubber  was 
collected. ' '  It  has,  however,  been  pointed  out  by  Ridley  and 
Green  that  the  insect  exudes  from  its  mouth  a  milky  substance,  like 
latex  in  appearance,  for  protective  purposes  ;  it  has  also  been 
suggested  that  the  latex  may  have  exuded  from  some  injury  or 
from  part  of  a  diseased  tree  and  trickled  down  to  the  ants'  nest. 

Insecticides  for  White  Ants. 

Before  proceeding  to  describe  the  general  methods  of  dealing 
with  white  ^nts,  a  word  is  necessary  as  to  the  substances  used  in 
killing  them. 

The  ordinary  soil  insecticides  in  powder  form  are  almost 
useless.     Though  carbon  bisulphide  liberates  fumes  that  are  very 


500  PARA    RUBBER 

destructive  to  the  ants,  its  cost  is  generally  prohibitive.  The 
most  efficient  remedy  appears  to  be  the  fumes  got  by  heating  white 
arsenic  with  sulphur  in  the  proportions  of  85  per  cent,  and  15 
per  cent,  respectively.  A  machine  for  generating  and  for  driving 
the  fumes  into  the  burrows  consists  of  a  charcoal  furnace  in 
connection  with  a  bellows  or  air-pump.  Some  of  the  sulphur 
and  arsenic  mixture  is  placed  upon  the  fire  after  it  is  brought 
to  a  glow,  and  the  Ud  fastened  down  A  tube,  with  a  nozzle 
for  inserting  in  the  burrows,  leads  from  the  furnace. 

General  Treatment  for  White  Ants 

In  treating  the  root  disease  Fomes,  the  drastic  remedy  of 
entirely  removing  the  whole  of  the  logs  and  stumps  from  the 
estate,  expensive  though  that  be,  is  sometimes  adopted  ;  it  is 
fortunate  that  such  measures  are  generally  protective  agamst 
white  ants.  And  while  it  may  not  appear  necessary  to  proceed 
to  do  this  where  white  ants  alone  are  present,  except  within  the 
■circumscribed  areas  affected,  removal  of  the  whole  of  the  dead 
•wood  upon  an  estate,  as  far  as  that  is  possible,  is  a  step  that  can  be 
recommended,  and  especially  its  removal  or  destruction  before 
planting  operations  are  begun. 

Pratt  (F.M.S.  Dept  of  Agric,  Bull.  No.  3),  has  made  some 
recommendations  that,  with  some  modification,  may  be  given 
in  brief.  It  will  be  seen  that  total  removal  of  the  dead  wood 
■on  an  estate  is  not  mentioned. 

Having  located  the  source  of  contamination  in  a  log  or  stump, 
icut  a  trench  around  it,  3  feet  away,  say,  4  feet  deep.  Leave 
this  open  for  a  few  days  ;  the  ants  will  construct  over  it  covered 
ways  leading  from  the  burrows  by  which  it  is  possible  to  locate 
the  latter.  After  these  are  known,  proceed  with  the  treatment, 
■dealing  first  with  the  log  or  stump.  Stop  up  the  ends  with  clay 
if  necessary,  and  bore  a  hole  into  which  the  fumes  may  be  pumped. 
Inject  the  fumes  for  six  minutes.  Crevices  allowing  fumes  to 
escape  must  be  plugged,  as  also  the  hole  after  pumping.  If  the 
log  is  long  enough,  make  other  holes  25  feet  apart  and  treat  as 
before.  Then  treat  the  burrows  between  the  trench  and  the 
tree,  from  the  base  of  which  fumes  should  escape  if  there  are  mud 
encasements  on  the  bark.  Should  no  fumes  escape  when  pumping 
into  the  runs,  then  find  the  ends  of  the  burrows  at  the  tree  and 
pump  there.  The  burning  of  the  log  or  stump  must  not  be  for- 
gotten. Should  it  be  impossible  to  locate  the  nest  or  the  burrows, 
then  destroy  all  the  dead  wood  within  the  affected  area,  dig  over 
the  soil  to  a  depth  of  at  least  3  feet,  adding  an  insecticide,  cind 
isolate  the  area  by  a  trench  four  feet  deep. 

The  trees  themselves  will  require  treatment.  If  they  are 
hoUow,  bore  a  hole  to  the  cavity  and  inject  the  fumes.  In  any 
case  ensure  that  the  runs  are  treated  at  their  bases.  Of  course, 
some  of  the  trees  may  be  beyond  hope,  and  must  be  burned. 


PARA     RUBBER  501 

Other  Insects  Attacking  the  Stem. 

Green  also  records  (T.A.  August,  1906),  a  case  of  infestation 
of  the  stem  of  a  Hevea  tree  "by  the  'horned  Termite,'  Termes 
inanis.  This  species  of  termite  takes  advantage  of  any  hollow  in 
a  tree  for  the  construction  of  its  nest."  Though  the  termites 
occupied  a  large  cavity  in  the  bole  of  the  stem,  the  tree  continued 
to  live.  Scooping  out  as  much  as  possible  of  the  pest,  and  flooding 
the  cavity  with  naphthalin  dissolved  in  petrol  proved  successful. 

Hevea  brasiliensis  has  been  attacked  by  a  borer  in  Java, 
the  report  being  to  the  effect  that  the  insect  proved  fatal  to  a 
seven-year-old  tree.  The  trunk  had  part  of  its  wood  exposed  and 
pierced  by  numerous  little  holes.  It  is  suggested  that  the  borers 
were  Scolytidse.  In  Ceylon  small  Scolytidse  (a  kind  of  beetle) 
have  often  been  found  in  dead  stems,  but  there  was  abundant 
evidence  of  the  previous  existence  of  a  parasitic  fungus. 

Green  states  that  he  has  repeatedly  received  specimens  of 
dead  branches  and  stems  of  Hevea  brasiliensis,  perforated  by  a 
Bostrichid  beetle — Xylopertha  mutilata — but  he  believes  that  in 
every  case  the  beetle  has  effected  its  entrance  after  the  death  of 
the  parts  He  also  records  the  ' '  shot-hole  borer ' ' — Xyleborus 
fornicatus — and  the  "brown  borer" — Arbela  quadrinotata.  The 
former  is  found  in  cankered  branches,  while  the  latter  strays  from 
Albizzias  and  enters  the  Hevea  tree  at  the  angle  of  a  branch  or 
in  the  fork  between  two  stems.  The  remedy  suggested  is  to 
plug  the  hole  with  tow  soaked  in  coal  tar. 

Pratt  mentions  that  a  borer  occurs  in  Malaya,  appearing 
invariably  upon  poUarded  trees,  rarely  spreading  to  the  unpoUarded 
trees  near,  and  then  only  at  tapped  surfaces.  Most  of  the  insects 
are  caught  in  the  latex  and  killed.  He  recommends  that  where 
lopping  is  performed,  tar  should  at  once  be  applied.  Ridley 
has  recorded  a  borer  of  the  genus  Platypus. 

The  caterpillars  of  a  little  moth — Comoetitis  pieria — feed  in 
Ceylon  on  the  outer  bark  of  the  trees,  but  seldom  cause  a  flow  of 
latex.  Their  galleries,  composed  of  fragments  of  bark  and  excreta 
fastened  together  with  a  silky  web,  can  be  easily  brushed  off  by 
hand. 

White  slugs — Mariaella  dussumerii — have  been  suspected  by 
Green  of  feeding  upon  the  renewing  bark  and  developing  buds, 
and  also  of  eating  the  remains  of  the  latex  left  in  the  wounds  after 
tapping.  ' '  Living  specimens  of  the  slugs  received  at  Peradeniya 
were  fed  with  fresh  latex.  Its  presence  was  almost  immediately 
scented  out  by  them.  One  of  them  drank  for  about  ten  minutes. ' ' 
Where  the  numbers  are  small,  hand-picking  will  be  effective. 
Should  the  slugs  be  numerous,  spread  a  broad  belt  of  ' '  Vaporite ' ' 
around  the  tree.  If  this  fails,  place  freshly-tarred  cylinders  of 
stout  paper  around  the  bases  of  the  stems. 

Considerable  harm  has  been  done  in  gnawing  of  stems  by 
rats  and  porcupines.  Maintaining  an  estate  in  a  clean  condition 
keeps  them  down  in  numbers  by  removing  possible  shelter. 
Green  (T.A.,  August,  1910),  suggests  the  hme  and  sulphur  wash 


503  PARA     RUBBER 

used  against  rabbits,  the  mixture  being  made  by  boiling  together 
3  lb.  quickhme,  3  lb.  flowers  of  sulphur,  and  6  gallons  of  water, 
until  the  whole  is  reduced  to  2  gallons. 

Root  Diseases. 

Fungi. — The  most  serious  root  disease  of  Hevea,  which  also 
occurs  on  the  first  six  inches  of  the  trunk  as  well  as  on  the  roots, 
is  Fom.es  semitostus.  The  disease  (F.M.S.  Dept.  of  Agric,  Bull. 
No.  2,  Gallagher),  is  not  discovered,  as  a  rule,  until  the  tree  is 
nearly  dead  ;  as  a  matter  of  fact,  often  when  the  tree  has  been 
blown  down  after  partial  destruction  of  its  root  system.  The 
first  symptoms  are  changes  in  the  leaves,  which  suddenly  become 
brown,  first  around  the  edges  and  especially  at  the  tips,  and  then 
entirely.  These  changes  are  often  preceded  by  a  curling  of  the 
leaf  edges  towards  the  under  side.  The  leaves  in  time  fall  off, 
but  generally  before  this  happens  the  tree  is  blown  down.  Upon 
examining  the  roots,  white  or  straw-coloured  cords,  each  formed 
of  a  number  of  fungus  threads,  are  found  running  irregularly 
over  them,  particularly  over  the  lateral  roots.  There  may  also 
exist  a  white,  cobweb-hke  felt,  mostly  upon  the  tap-root.  An 
infected  tap-root  will  be  black  in  colour  instead  of  the  usual 
healthy  white.  Its  cortex  is  soft  and  rotten,  and  the  hard  wood 
below  is  discoloured. 

Characters  of  Fomes. 

The  fruiting  part  of  the  fungus — which  produces  the  spores, 
that,  carried  by  the  wind  or  water,  form  new  centres  of  infection — 
is  not  very  common,  and  is  found  on  decaying  logs  or  dead  trees, 
where  they  are  exposed  to  the  air.  It  has  been  described  as  follows 
(Straits  Bulletin,  May,  1904) :  ' '  the  fruiting  part  of  Fomes  semitostus 
is  a  broad,  flat,  rounded  plate  often  very  irregular  in  form,  usually 
reniform,  4  to  6  inches  across,  and  of  an  orange-red  colour  beneath, 
paler  above,  where  it  is  marked  with  rings  and  fine  striae  ;  beneath 
can  be  seen  with  a  lens  the  honeycomb-like  structure  of  the 
hymeneal  surface.  The  texture  of  the  fungus  is  tough,  and  it 
possesses  a  strong  mushroom-like  scent. ' ' 

Mitchell  states  that  the  fruit  at  maturity  forms  a  semi- 
circular or  kidney-shaped  bracket  attached  to  a  dead  stump  or 
root.  The  upper  surface  is  yellow-brown  marked  by  a  series  of 
darker  concentric  lines.  The  under  surface  is  orange  or  red- 
brown  If  cut  vertically  the  upper  half  is  white  and  the  lower 
brown. 

The  original  source  of  infection  is  frequently  a  diseased 
jungle  stump  or  log,  when  this  happens  to  be  reached  by  a  growing 
lateral  root.  Along  this  the  disease  extends,  killing  the  root 
as  it  goes,  eventually  reaching  the  tap-root,  and  then  passing  to 
the  other  lateral  roots.  From  an  infected  tree  it  may  spread  to 
healthy  trees  in  the  neighbourhood.  The  disease  can  spread 
also  by  independent  growth  through  the  ground,  especially 
in   low-lying,  damp,  heavy,    and   badly-drained   soils    (Bancroft, 


PARA     RUBBER  503 

Agr.  Rep.  F.M.S.,  1910).  Mitchell  has  observed  it  on  stumps 
of  jungle  trees  to  a  depth  of  over  three  feet,  though  usually  it 
occurs  at  i  to  i^  feet  below  the  surface. 

Percentage  of  Deaths  .Due  to  Fomes, 

There  can  be  no  doubt  that  Fomes  is  the  most  serious  pest 
with  which  rubber  planters  have  so  far  had  to  deal  with,  A  very 
large  number  of  trees  are  attacked  almost  every  month  and 
deaths  are  recorded  frequently.  On  one  estate  where  Fomes 
only  appears  to  seriously  affect  trees  over  two  to  three  years  old, 
a  monthly  record  of  trees  showing  symptoms  of  the  disease  is 
being  kept.  The  affected  area  is  only  500  acres  in  extent,  yet  the 
number  of  trees  killed  in  certain  months  were :  April,  97  ; 
August,  118  ;  September,  100  ;  October,  54.  A  very  high  per- 
centage of  vacancies  must  therefore  be  expected  on  estates  in 
Malaya.  In  Ceylon,  Java,  and  Sumatra,  where  the  soil  is  usually 
drier,  there  does  not  appear  to  be  the  same  destruction  due  to 
Fomes. 

Conditions  Affecting  Fomes. 

There  are  certain  conditions  which  appear  to  encourage  the 
spread  of  Fomes.  This  fungus  commences  as  a  saprophyte — one 
living  on  dead  matter — and  on  the  living  roots  of  Hevea  trees  it 
becomes  a  true  parasite.  It  is  also  possible,  where  the  roots  of 
Hevea  trees  have  been  partially  destroyed  by  forking,  trenching, 
attacks  of  white  ants,  etc.,  that  the  fungus  may  commence  on  the 
dead  part  of  the  root  and  spread  to  the  living  portion  of  the  same 
structure.  Hence  the  necessity  to  avoid  undue  destruction  of 
rootlets  of  Hevea  trees  when  carrying  out  manuring  and  tillage 
on  the  estate. 

This  capacity  of  the  fungus  to  change  from  a  saprophyte  to 
a  parasite  is  probably  closely  associated  with  the  frequent  preva- 
lence of  white  ants  and  the  fungus  on  the  same  spot.  On  the 
other  hand,  it  is  conceivable  that  white  ants,  by  destroying  dead 
material,  may  ultimately  remove  substances  on  which  Fomes 
might  have  commenced  to  grow. 

Mitchell,  of  Lanadron,  states  that  it  spreads  very  rapidly  in 
loose,  friable  soils  such  as  sand  and  loams. 

Remedial  Methods  for  Fomes. 

The  remedial  measures  recommended  by  Gallagher  in  the 
treatment  of  an  infected  area  are  :  (i)  remove  all  timber,  roots, 
stumps,  logs  and  bits  of  branches  and  burn  them  ;  (2)  trench 
(changkol)  over  the  soil  a  couple  of  times  to  a  depth  of  two  feet  to 
expose  fungal  threads  in  it  to  the  sun  and  thus  kill  them  ;  (3)  use 
lime  every  time  the  ground  is  turned  over.  All  diseased  trees 
within  the  area  must  be  removed.  When  a  diseased  lateral  root 
of  an  apparently  healthy  tree  is  met  with,  it  must  be  cut  off  at  a 
point  six  inches  above  the  diseased  part,  and  the  specially  treated 
area  of  the  soil  extended  as  far.     Where  root  disease  has  been 


504  PARA     RUBBER 

neglected,  and  is  present  in  scattered  areas  over  the  estate,  as  a 
preliminary  treatment  a  trench  2  feet  deep  and  a  changkol  wide, 
should  be  dug  round  each  area.  The  trench  should  not  be  less 
than  3  feet  away  from  the  certainly  healthy  trees.  Supplies  may 
be  put  in  just  after  the  last  digging  over,  but  it  is  better  to  wait 
for  eight  weeks. 

Other  Root  Diseases. 

The  ' '  brown  root  disease ' ' — Hymenochaete  noxia —  is  found 
in  Ceylon,  Malaya,  Samoa,  and  New  Guinea,  and  probably  also  in 
South  India  and  Java  (Circ,  R.B.G.,  No.  6,  Vol.  V).  It  is  not  very 
dangerous,  for  it  spreads  very  slowly,  and  only  one  tree  is  killed 
at  each  centre  of  infection  unless  a  tree  killed  by  the  fungus  is  left 
standing  for  two  or  three  years.  As  with  other  root  diseases,  the 
leaves  of  the  tree  wither  and  fall  off,  and  the  tree  eventually  dies. 
A  thick,  yellowish-brown  felt,  which  later  develops  a  black  crust 
exteriorly,  covers  the  roots,  and  to  this  covering  are  attached  stones, 
sand,  etc.  The  fruiting  part  is  a  thin,  dark-brown  crust  adhering 
to  the  base  of  the  stem.  Nearly  all  the  cases  arise  where  cacao 
has  been  cut  out,  the  stumps  being  liable  to  encourage  the  disease 
and  pass  it  on  to  the  Hevea  when  the  roots  of  the  latter  come  into 
contact  with  them.  The  remedy  is  to  dig  out  and  burn,  with  any 
neighbouring  cacao  stump,  and  afterwards  lime  the  ground. 

A  third  root  disease — Spaerostilbe  repens — has  been  found 
in  Ceylon  (Circular,  R.B.G.,  No.  8,  Vol.  V.),  but  cases  are  few. 
The  fungus  forms  red  cords — which  become  black  on  decajdng — 
between  the  wood  and  cortex,  especially  at  the  collar,  where  it 
may  become  a  continuous  sheet.  One  form  of  fruiting  appears 
at  the  collar  as  a  dense  cluster  of  small,  red  stalks  with  white 
heads.  The  wood  of  the  affected  parts  is  deep  blue  when  fresh, 
fading  when  it  dries.  The  sources  of  infection  are  pieces  of  jak- 
wood.  Dig  up  and  burn  the  dead  trees  and  any  jak  stumps,  and 
collect  and  burn  all  pieces  of  wood  which  may  encourage  the 
fungus.  Surround  the  infected  area  with  a  trench,  and  fork  in 
lime. 

Considerable  damage  has  been  done  on  the  Gold  Coast  by  a 
fungus — Rosellinia  sp. — that  attacked  the  roots  and  the  collars 
of  the  stems  (Report,  Dir.  of  Agr.,  Gold  Coast,  1909).  The  trees 
were  removed  and  burnt,  the  areas  trenched,  and  dug  over  with 
lime. 

Insect  Pests. — Specimens  of  a  termite — T.  redemanni — 
have  been  sent  with  the  report  that  they  were  eating  off  the  tap 
roots  of  young  rubber  plants.  It  is  practically  certain  that  the 
white  ants  have  followed  on  fungal  root  disease,  and  they  may  be 
treated  by  the  usual  methods. 

Grubs  of  the  large  cockchafer — Lepidiota  pinguis — have  been 
received  by  Green  (T.A.,  Oct.,  1905),  from  Yatiyantota,  Ceylon, 
with  the  report  that  they  are  found  about  two  inches  below  ground- 
level.  It  is  stated  that  the  pest  bites  through  a  live  stump  (of 
Para  rubber)  of  any  size.     The  only  way  one  can  tell  that  it  is 


PARA     RUBBER  505 

working  is  by  seeing  the  green  shoot  on  the  stumps  die  back. 
On  touching  the  stump  it  breaks  off.  The  taproot  has  been 
severed  an  inch  or  two  below  the  collar,  and  every  vestige  of  a 
side  root  has  disappeared.  Alkaline  manures,  such  as  kainit  and 
nitrate  of  soda,  have  been  found  useful  in  driving  away  cockchafer 
grubs.  The  manure  should  be  forked  in  round  the  plants  in 
clearings  affected  by  the  pest.  "The  adult  beetle  is  of  a  con- 
siderable size,  being  fully  an  inch  long  and  proportionately  stout. 
The  larva  is  a  white  fleshy  grub,  two  inches  in  length,  the  body 
curved  round  into  the  form  of  a  horse  shoe.  It  has  very  powerful 
jaws,  with  which  it  works  great  havoc  on  the  roots  upon  which 
it  feeds." 

Green  also  mentions  the  grub  of  another  kind  of  large  beetle 
(Circ,  R.B.G.,  No.  12,  Vol.  IV.)  that  tunnels  the  tap-root  and 
works  into  the  stem. 


CHAPTER     XXXII. 

COST    OF    PRODUCTION    ON    ESTATES. 

The  cost  of  producing  Hevea  rubber  on  estates  in  the  East 
has,  since  the  inception  of  the  industry,  been  the  subject  of  much 
discussion.  Hitherto  tapping  has  usually  been  carried  out  only 
on  a  relatively  small  number  of  trees  often  scattered  through  the 
estate.  Where  only  from  lo  to  50  per  cent,  of  the  trees  on  a  given 
area  are  in  a  condition  fit  to  be  tapped,  it  is  but  reasonable  to 
expect  that  the  cost  of  collecting  will  be  proportionately  high. 
When,  furthermore,  the  trees  are  being  tapped  for  the  first  time 
the  bark  tissue  wherein  the  latex  accumulates  is  thin  and  soft,  and 
a  low  yield  of  rubber  per  cooly  employed  can  be  expected.  Guided 
by  the  results  of  a  few  years  experience  in  the  tropics,  it  was 
predicted  that,  when  estates  reached  maturity,  the  production 
of  rubber  would  be  accomplished  at  from  is.  to  is.  6d.  per  lb., 
the  lower  cost  being  characteristic  of  countries  where  labour  is 
cheap  and  well  trained,  and  the  higher  figure  for  areas  where 
labour  conditions  are  less  favourable. 

Variations  in  Systems  of  Costing. 

The  great  range  in  the  cost  of  production  shown  later  in 
this  chapter  can  be  explained  partly  by  the  different  methods 
adopted  in  compiling  the  accounts  of  the  respective  companies, 
but  the  outsider  must,  except  some  general  agreement  is  arrived 
at,  remain  in  ignorance  of  the  actual  items  covered  by  the  headings 
given.  Where  an  estate  possesses  only  a  few  scattered  mature 
trees,  and  more  than  one  product  is  cultivated  on  the  same  area, 
a  reasonable  excuse  can  be  given  for  not  detailing  the  items  con- 
cerned. If,  however,  the  whole  area  is  in  bearing  and  all  estate 
and  managerial  items  are  chargeable  against  the  rubber  harvested, 
there  is  not  the  slightest  excuse  for  keeping  secret  the  cost  per 
pound  of  rubber.  Detailed  information  of  this  character  should 
prove  exceedingly  valuable  to  directors  in  Europe,  and  managers 
abroad,  when  comparisons  are  made  between  the  various  items 
in  monthly  reports  from  different  estates. 

It  is  very  difficult  to  form  a  correct  idea  of  the  average  cost 
incurred  in  marking  trees,  tapping  and  collecting,  curing,  freight, 
packing-cases  and  packing,  tapping-knives,  etc.,  owing  to  the 
fact  that  each  estate  has  its  own  system  of  accounts.  Further- 
more, on  estates  which  are  planted  with  tea  and  other  products 
in  addition  to  rubber,  a  varying  proportion  of  the  capital  expenses 
are  charged  against  the  rubber,  according  to  the  system  of  accounts 
adopted. 


PARA     RUBBER  507 

Cost  in  Ceylon  in  1908. 

In  the  second  quarter  of  1908,  I  visited  several  rubber  pro- 
perties in  Ceylon  possessing  a  large  number  of  Hevea  rubber 
trees  of  different  ages  in  bearing.  On  only  one  occasion  was  the 
superintendent  unable  to  produce  rubber  at  a  profit — on  paper — 
with  rubber  at  3s.  per  lb.  In  that  particular  case,  all  the  trees 
were  from  four-and-a-half  to  five  years  old,  and  the  youthfulness 
of  the  property,  with  the  inexperience  of  the  man  in  charge, 
were  probably  responsible  for  such  a  condition  of  affairs. 

The  cost  of  production  varies  considerably  on  estates  in 
the  same  district,  and  especially  when  the  plantations  are  of 
different  ages.  On  one  well-known  Kalutara  property,  the  rubber 
during  1907  was  delivered  f.o.b.  Colombo  at  80  cents  (100  cents 
equal  i6d.).  On  the  same  property  it  was  estimated  that  in  the 
future,  with  the  whole  of  the  estate  in  bearing,  the  cost  would 
be  reduced  to  55  cents  per  lb.  On  another  property,  the  cost 
of  the  rubber  from  young  trees  was  85  cents,  and  that  from  old 
trees  48-15  cents.  ,  The  superintendent  hoped  to  be  able  to  bring 
down  the  cost,  f.o.b.  Colombo,  to  50  or  60  cents  per  lb.  On 
another  property,  the  cost  of  production,  including  all  charges 
in  Colombo  and  London,  was  Rs.  i-io  from  old  trees,  and  Rs. 
1-50  from  young  trees.  The  superintendent  estimated  that  the 
cost  in  the  future  would  be  R.  i  per  lb.  when  his  cooly  average  was 
35  cents  per  day.  It  is,  therefore,  quite  obvious  that  even  in 
the  same  district  or  country  there  is  a  considerable  variation  in  the 
costs  of  production. 

Influence  of  Labour  on  Tapping  Costs. 

The  average  daily  cost  of  cooly  labour  has  a  great  influence  on 
the  cost  of  production.  There  are  many  estates  in  Ceylon  and 
Malaya  where  the  daily  average  is  38  cents,  but  in  the  former 
country  that  is  equivalent  to  6d.  and  in  the  latter  io|d.  Fraser 
(I.R.J.,  Aug.  22nd,  1910)  stated  that  tapping  was  being  done  at 
from  10  to  18  dollar  cents  by  Tamils  and  22  to  25  cents  by  Chinese, 
but  this,  he  thinks,  will  be  greatly  improved  upon.  A  planter 
in  the  F.M.S  felt  certain  that  with  crops  of  500  lb.  per  acre,  the 
f.o.b.  cost  of  rubber  might  be  brought  down  to  8d.  or  gd.  with 
Tamil  tapping  in  F.M.S.  ;  is.  to  is.  id.  with  Chinese  tapping  in 
F.M.S.  ;  4jd.  in  Ceylon  without  manuring  ;  6d.  in  Ceylon  with 
manuring. 

Another  point  which  influences  cost  is  that  some  managers 
■charge  the  actual  cost  of  the  labour  employed  in  tapping  against 
that  item,  instead  of  charging  the  average  cooly  cost  over  the 
whole  estate.  A  case  in  point  was  where  the  tapping  coolies  were 
paid  at  the  rate  of  45  cents,  when  the  cooly  average  over  the 
property  was  35  cents.  On  another  property,  where  the  average 
rate  of  cooly  pay  was  the  same,  the  cost  per  day  for  tapping 
coolies  was  below  the  average,  viz.,  30  cents,  on  account  of  only 
podians  (boys)  and  women  being  employed  for  such  work.  Weed- 
ing and  other  work  is  just  as  essential  as  that  more  directly  con- 


5o8  PARA     RUBBER 

cerned  with  the  collection  and  preparation  of  rubber,  and  it  would 
appear  to  be  fairer  to  charge  the  average  cooly  cost  for  the  estate 
rather  than  the  cost  of  individuals  employed  for  the  time  being  on 
this  particular  work. 

Other  Factors  Affecting  Cost. 

It  is  obvious  that  the  cost  of  production  must  also  be  largely 
determined  by  the  ages  of  the  trees  and  methods  of  tapping 
employed.  The  yield,  and  therefore  cost,  also  varies  according 
to  the  distance  between  the  trees,  the  percentage  of  trees  in  the 
tapping  round,  the  season,  and  the  percentage  of  crop  grades. 
The  large  variation  in  the  cost  of  tapping  knives  alone  will  account 
for  considerable  differences  between  the  costs  of  production  on 
adjacent  estates.  Land,  river,  and  sea  transports,  local  agency 
charges,  and  many  other  factors  are  also  responsible  for  the 
enormous  variation  in  cost  at  the  present  time. 

Daily  Tasks  in  Collecting. 

The  weight  of  rubber  brought  in  by  each  cooly  per  day  has 
been  given  in  the  annual  reports  of  various  companies.  On 
Lanadron  estate  the  cooly  outturn  in  1908  (trees  5  to  9  years) 
was  3-67  lb.  per  day  ;  in  1909  (trees  6  to  10  years)  3-18  lb.  ;  in 
1910  it  was  2-63  lb.  from  trees  3  to  11  years.  Ledbury  estate 
obtained  2-14  lb.  per  cooly  per  day  in  1909  (trees  7  to  10  years), 
and  2-97  lb.  in  1910  (trees  3  to  11  years).  On  Sione  estate  2-69  lb. 
per  cooly  were  obtained  in  1909  from  trees  4  to  12  years  old,  and 
1-97  lb.  in  the  following  year  from  trees  3  to  13  years  old.  The 
Singapore  and  Johore  Rubber  Company  report  a  completed  task 
of  2-32  lb.  per  cooly  for  1910.  Jementah  estate  report  i-2i  lb.  in 
the  same  year,  the  trees  on  this  property  being  4  to  6  years  old. 

On  several  estates  an  outturn  of  5  lb.  of  rubber  per  day 
per  cooly  is  obtained  from  ten-year-old  trees,  a  fact  which  indicates 
that  a  considerable  reduction  in  cost  of  collecting  rubber  wiU  be 
possible  when  Hevea  trees  reach  the  age  mentioned. 

Proportionate  Cost  on  Estate. 

If  the  accounts  of  estates  in  full  bearing  are  examined  it  will 
invariably  be  found  that  the  main  item  of  expense,  on  the  estate, 
is  that  included  under  the  heading  of  tapping  and  manufacture. 
This  amounts  generally  to  from  50  to  80  per  cent,  of  the  total 
cost  of  production,  and  includes  costs  of  tapping,  utensils,  washing, 
drying,  packing,  transport,  and  shipping.  Cost  of  cultivation, 
which  includes  roads  and  drains,  weeding,  supplying,  pests, 
forking,  and  tools,  is  usually  next  in  amount,  and  averages  about 
10  to  15  per  cent,  of  the  total  cost.  Buildings  and  repairs  are 
usually  from  5  to  7  per  cent.  General  charges  also  vary,  including 
salaries,  insurance,  local  and  visiting  agency  fees,  rent,  medicsd. 
and  contingencies,  etc.,  and  on  estates  in  view  account  for  from 
10  to  16  per  cent,  of  the  total  costs  of  production.     To  the  above 


PARA     RUBBER 


509 


must  be  added  London  costs,  which  include  offices  directors'  fees, 
and  commissions. 


Standardization  of  Accounts. 

It  would  be  advantageous  if  managers  in  the  same  district 
or  country  could  adopt  the  same  form  of  accounts,  as  it  would 
enable  them  to  compare  the  costs  of  the  various  items  with  similar 
charges  on  neighbouring  properties.  It  would  also  be  a  boon 
to  accountants  and  directors.  An  attempt  has  been  made  by 
H.  K.  Rutherford  to  supply  the  necessary  form,  the  actual  charges 
incurred  upon  a  Malayan  estate  being  added  : — 


General — 

Salaries    . . 

Allowances 

Visiting  and  Agent's  fee 

Quit  Rent 

Hospital  charges 

Fire  insurance 

Stationery  and  postages 

Cattle 

Recruiting 
Contingencies 


Cultivation — 

Weeding 

•  •      4-53 

Roads,  bridges  and  drains     . . 

• .       1-30 

Supplying 

•24 

Pests  and  diseases 

•46 

Tools 

•07 

Upkeep  of  Buildings,  etc. — 

Bungalows 

•15 

Lines    . . 

•29 

Factory  and  Stores     . . 

•17 

Cattle  sheds 

•06 

Machinery 

•16 

Rubber  Manufacture — 

Marking  trees 

•42 

Tapping  and  scrapping 

. .      14-04 

Curing,  including  fuel 

•  •        1-54 

Utensils           

■59 

Packages 

i-i8 

Transport,  including  rail 

•58 

Forwarding  charges   . . 

•08 

Duty 

4-24 

per  lb. 
4'73  dollar  cents. 
•40 
•22 

■43 
■80 

■17 
■10 
•10 
-75 
•57 

8-27 


6-6o 


Freight 

Warehouse  charges 
Sale  expenses 
Brokerage    . . 
Marine  insurance    . 
Discount  and  draft 


■68  pence 

■33 
•04 
■29 
■23 
173 


0-83 


22'67 

38-37   =   10-75  pence 


3"30 


14-05  pence. 


I 

2 

3 

4 

5 

0-46 

0-28 

nil 

nil 

nil 

6-31 

7-02 

7-2 

8-4 

7-2 

272 

3-4 

13 

0-6 

l-i 

— 

028 

o'3 

— 

0-2 

0'26 

0-6 

o-i 

02 

O-I 

2-46 

i'i5 

— 

— 

1-9 

— 

— 

0-2 

— 

o-i 

510  PARA     RUBBER 

Principal  Costs  Itemised. 

It  has  been  shown  that  the  principal  cost  on  a  mature  estate 
is  that  included  under  the  heading  of  ' '  tapping  and  manufacture. 
The  costs  of  each  item  in  this  charge  vary  according  to  estate 
conditions,  and  whether  or  not  large  numbers  of  trees  are  being 
regularly  taken  into  the  tapping  round. 

The  following  table  is  compiled  from  actual  costs  on  different 
estates  in  the  East  : — 

Cost  in  pence  per  lb.  of  Rubber  harvested. 
Items. 
Marking  trees 
Tapping  and  utensils 
Washing  ajid  drying 
Packing  and  packages    .  . 
Transport 
Shipping  charges 
Factory  requisites 
Insurance  . .  .  .     0-42  o'23  —  —  — 

The  series  numbered  i,  2,  4,  and  5  relate  to  estates  in  Malaya 
and  Sumatra,  number  3  to  Ceylon.  Estates  i  and  2  are  young,  and 
several  thousands  of  trees  are  being  taken  into  the  tapping  round 
every  month,  the  yield  being  about  3,000  lb.  per  month.  Estate 
number  3  is  a  Ceylon  property  with  the  greater  part  in  bearing, 
and  yielding  5,000  lb.  per  month.  Number  4  is  a  Sumatran 
estate,  giving  2,000  lb.  of  rubber  monthly  from  young  trees. 
Number  5  is  an  estate  in  full  bearing,  and  yielding  over  20,000  lb. 
per  month. 

The  Kuala  Lumpur  Rubber  Company's  report  for  1910-11 
states  that  the  cost  of  collecting  was  19-27  dollar  cents  per  lb., 
as  against  19-73  cents  for  the  previous  year  ;  and  it  also  reports 
that  curing  costs  were  4-19  cents  per  lb.  as  against  3-42  cents  for 
1909-10.  It  further  states  that  the  cost  of  production  and 
marketing,  for  a  crop  of  676,648  lb.  of  dry  rubber,  was  2od.  per  lb., 
as  against  igd.  per  lb.  for  the  previous  year. 

Lanadron  reports  that  the  cost  of  marking  trees,  tapping 
and  transport- to  the  factory  cost  16-69  cents  per  lb.  for  Lanadron, 
estate,  and  32-30  cents  for  Jementah  estate.  Highlands  and 
Lowlands  quotes  15-87  cents  per  lb.  for  tapping  on  Highlands 
estate,  and  12-11  cents  on  Batu  Unjor.  Ledbury  costs  for  tapping 
and  scrapping  were  10-16  cents,  and  Pataling  9-49  cents  per  lb. 
Selangor  gives  19  cents  as  the  cost  per  lb.  of  tapping  and  curing, 
including  the  cost  of  tools  and  utensils.  The  cost  of  tapping  and 
scrapping  on  Chersonese  was  i7id.  per  lb. 

Costs  f.o.b.  Colombo,  Madras  and  Belawan. 

Though  I  am  unable  to  state  what  items  are  included  under 
the  heading  of  "cost  of  production"  in  the  reports  of  various 
companies,  the  following  figures  should  prove  of  some  value  as 
showing  the  costs,  in  pence  per  lb.  of  rubber,  free  on  board  in 
Colombo,  Madras,  or  Belawan  :— 


PARA     RUBBER 


511 


Ceylon. 

South  India. 

Estate.                      Costs. 

Estate. 

Costs. 

Eastern  Produce 

■      i3i 

Malayalam  . . 

■      i6's 

Arapolakande 

9i 

Rani  Travancore    . . 

•     23 

Panawatte  . . 

.     26J 

Rosehaugh  . . 

.        I2i 

Sumatra. 

Doranakande 

•    III 

Langkat  Sumatra  .  . 

•        6J 

Yatiyantota 

•    15 

United  Sumatra 

.      12 

Sapumalkande 

.  21J 

Sumatra  Para 

■      13J 

Sittawa 

.  20J 

United  Serdang 

■    i9i 

Moneragalla 

■      i6i 

Grand  Central 

•      I5t°o 

NagoUe 

.        22i 

Lavant 

•         14 

It  would  be  interesting  to  know  what  proportion  of  estate 
charges  have  been  debited  against  the  rubber  from  each  of  these 
estates.  On  Lavant  3d.  per  lb.,  included  in  the  cost  of  i4d., 
was  for  weeding  and  manuring. 

Costs  in  Malaya. 

There  are  many  estates  in  Malaya  whereon  the  costs  of  the 
various  items  are  known.  The  variation  in  the  costing  system 
adopted  is  enormous,  some  giving  the  cost  f.o.b.,  others  c.i.f.,  and 
others  with  or  without  a  proportion  or  the  whole  of  salaries, 
bonuses,  and  London  charges. 

On  a  few  estates  the  cost  of  collecting,  together  with  all 
charges  and  London  expenses,  are  given  : — 

Items  Included  in  Cost. 
Directors'  fees,  London  office  expenses, 

bonuses,  depreciation. 
Directors'  fees,  London  office  expenses. 

Do.  do. 

Excluding  London  expenses. 
London,  expenses. 

All  London,  and  proportion  local  expenses 
London  expenses  not  included. 
C.i.f.  London. 
Total  cost  of  marketing. 
Part  of  London  expenses. 
Freight,  duty,  insurance,  commission. 

Do.  do.  do. 

Total   revenue   expenditure,    home    and 

colonial. 
Including  establishment  charges . 

The  above  list  indicates  items  charged  in  addition  to  the 
actual  costs  on  the  estates.  The  following  figures  show  the 
proportions  of  the  various  items  in  two  producing  companies  : — 


Estate. 

Cost. 

Pataling 

i2d. 

Selaba 

22d. 

Bikam 

Kuala  Lumpur 

Merton 

34id. 

20d. 

3id. 

Batu  Tiga 
Castlefield 

22id. 

25d. 

Kapar  Para     .  . 
Sungei  Kapar 
Kuala  Selangor 
Buldt  Lintang 
Inch  Kenneth .  . 

I4d. 
I4id. 

2lT-»od 

igfd. 

24id. 

Carey  United  . . 

23id. 

Rembia 

i5id. 

Items  included  in  cost. 
F.o.b.  including  export  tax  (ifd.) 

Freight  and  selling  charges. 

Directors'  fees,  London  expenses, 
and  management. 


Bukit 

Rajah. 

I2d. 

4d. 


Consolidated 
Malay. 
I2'76d. 

213d. 


lid. 


5'ood. 


Items  included 

in   cost. 

General  charges  and 

upkeep  expenses. 
Duty,  transport,  and 
shipping    charges. 
London  costs,  ex- 
warehouse. 


Totals 


IS.  54d. 


IS.  8d. 


512  PARA     RUBBER 

It  is  quite  conceivable  from  the  above  statistics  that  should 
the  trees  yield  double  their  present  daily  outturn,    the  cost  per 
lb.   will  be  brought  near  to  one  shiUing  (including  all  charges) 
-  per  pound  of  rubber  in  future  years. 

Costs  f.o.b.  Port  Swettenham  and  Penang. 

An  instructive  lesson  may  be  gained  from  a  study  of  the  costs 
of  the  rubber  delivered  at  Malayan  ports.  The  following  are  the 
costs,  in  pence,  f.o.b.  Port  Swettenham  ; — 

Seaport,  32f d. ;  Sungei  Choh,  i8Jd.  ;  London  Asiatic,  i6d.  ; 
Sandycroft,  i4d. ;  Golden  Hope,  i2|d. ;  Golconda,  I2d.  ;  Anglo- 
Malay,  13d. 

The  costs  f.o.b.  Penang  were  i8d.  for  Allagar  ;  i^^d.  for  Cicely ; 
I2fd.  for  Jebong  ;    and  39-94d.  for  Chersonese. 

The  costs  f.o.b.  Teluk  Anson  were  igd.  for  Selaba,  and  33fd. 
for  Sungei  Chumor. 

Other  companies  have  published  the  costs  f.o.b.  without 
mentioning  the  port  of  shipment.  Bikam  cost  28|d.  ;  Batak 
Rabit,  28Jd.  ;  Kurau,  26d.  ;  Straits  Rubber,  22d. ;  Rubana,  igd.  ; 
Perak  and  Labu  each  ly-^d.  ;  Linggi,  isjd.  ;  Kamuning,  I5d.  ; 
and  Sendayan,  37"39d.  per  lb. 

It  must  be  understood  that  all  costs  mentioned  in  this  chapter, 
except  where  it  is  otherwise  noted,  refer  to  the  financial  years 
1910  or  1910-11   of  the  respective  companies. 


CHAPTER  XXXIII. 

ESTIMATED    COSTS   OF   PLANTING. 

The  cost  of  clearing,  draining,  planting  and  up-keep  of 
large  acreages  of  Hevea  necessarily  varies  according  to  the 
condition  of  the  forests  to  be  cleared,  the  nature  of  the  land, 
and  the  rates  of  wages  paid,  &c. 

In  the  last  edition  I  was  able,  through  the  courtesy  of  various 
friends,  to  give  estimates  for  the  opening  out  of  estates  in  various 
parts  of  the  Middle-East.  Owing  to  increases  in  labour  costs 
and  that  of  superintendence,  the  much  heavier  expenditure 
upon  machinery  and  buildings  now  considered  necessary,  the 
aggregate  cost  of  bringing  an  estate  into  bearing  has  reached 
figures  that  were  once  unexpected.  This  has  demanded  a  revision 
of  the  estimates,  atid  I  am  again  indebted  to  some  of  'my  friends 
for  the  information  they  have  supplied.  In  the  case  of  the  Ceylon 
estimates  I  have  decided  to  leave  them  untouched,  with  the  proviso 
that,  the  charges  being  now  heavier,  the  total  costs  must  be 
increased  by  lo  or  15  per  cent.  ;  the  same  remark  applies  to  Java. 

Rubber  Planting  in  Ceylon. 

Estimate    I. 

Estimate  of  Cost  of    Purchasing    100  acres  of  Land  and 
Planting  with  Hevea — Matale  District. 

Cost  of  100  acres  of  Land —  Rs. 

Forest  say  at  Rs.  60  per  acre     |         „„ „„„„ 

Chena  ,,         40  to  Rs.  45  J^^y  ^"- 5°  P^-^ ^'^^^       ••  ••  S.ooo 

Clearing — 

100  acres  Forest  at  Rs.  20  per  acre     I  ,-> 

WacresChenaatRs.  istoRs.  17   I      say  Rs.  17  50  per  acre  1,750 

Nurseries  AND  Seeds — 40,000  seeds  at  Rs.  7  per  1,000  Rs.280     o 

30,000  Baskets,  Rs.  4  per  1,000  ..  ..  120     o 

Making  nurseries,  including  sheds  for  basket  plants, 

sowing  seed .  .  . .  . .  . .  60     o 

Upkeep,  watering  for  3  months  regularly  . .  30     o 

Further  occasional  attendance  for  6  months         .  .  20     o 


510 

Roads  and  Drains — at  Rs.  6  per  acre      ..  ..  ..  600 

Lining — say  15'  by  15' — about  200  trees  per  acre,  including  cost 

of  pegs,  at  75  cents  per  acre  ..  ..  ..  75 

Holing — -Holes  18"  by  12"  :  task  40  per  man,  say  Rs.  i 'So  per  acre  180 

Planting — 20,000    Basket    plants,    including     transport     from 

nurseries,  dipping  in  liquid  manure,  &c.,  80  cents,  per  acre  ..  80 

Supplying — Putting  out  6,000  basket  plants  at  50  cents  per  100    ..  30 

Shading — 30,000  cadjans  at  Rs.  10  per  1,000  ..     Rs.    300 

Making  up,  fixing,  and  general  attendance,  say  Rs. 

I -50  per  acre  ..  ..  ...  150 


450 


GG 


314 


PARA     RUBBER 


Lines — i  set  of  temporary  lines,  20  rooms,  jungle  post  thatched 

roof,  mud  and  wattle  walls,  at  Rs.  20  per  room  .  . 
Weeding — Forest  land,  first  3  months  at  Rs.  i"25,  thereafter  at  80 
cents,  say  10  months'  weeding  at  Rs.  I'jo  per  acre 
Chena  Land  : 

First  3  months  at  Rs.  2-50  1 
Second  3  months  ,,  i'75  [■ 
Thereafter  „    I'o      J 


Fencing.- 


-Cost  of  wire  and  staples     ) 

about  Rs.  150  per  mile,       | 

3  wires  at  i  foot  apart         ! 

Posts  :  cutting  holes,  &c.,      [ 

and  fixing,  Rs.  30  per  mile 
Carpenters  at  Rs.  7  per  mile  J 
Tools 

Contingencies 

Superintendence  at  Rs.  100  per  month    . . 
Coast  Advances  ;  80  coolies,  say  Rs.  30  each 


Add  interest  on  Rs.  14,936  at  7% 


Rs.  187  per  mile  for 
3  miles 


Rs. 


Rs. 


Rs. 

400 
1,500 


561 


100 

100 

1, 200 

2,400 

14.936 
1.045 

15,981 


2nd  Year      ...     Superintendence 

Weeding  100  acres  at  R.  i 
Nurseries,  suppljdng  cadjans,  &c. 
Roads  and  drains  upkeep  .  . 
Thatching  lines  Rs.  i  '50  per  room 
'  Upkeep  of  fence 

Contingencies 

Add  intereston  Rs.  18,511  at  7% 


3rd  Year      Superintendence 

Weeding  at  80  cents 

Suppljdng  and  nurseries 

Roads  and  drains 

Lines 

Fencing 

Contingencies 

Add  interest  on  Rs.  2 1 , 8 1 6  at  7  % 


4th  year  . .         Superintendence 

Weeding  at  75  cents 

Supplying,  &c. 

Lines  :      20   rooms — permanent  stone 

pillars,  mud  and  wattle  walls,  iron 

roof,  Rs.  70  per  room 
Fencing 
Contingencies 

Interest  at  7% 


Rs. 

1,000 

1,200 

105 

50 

30 

50 

100 


2.535 
1,290 


Rs. 

19,806 

900 

800 

100 

50 

30 

30 

100 

2,010 

1.527 

Rs. 

23.343 

720 

750 

100 

1,400 

30 

70 

3.070 

1,848 

Rs. 


28,261 


PARA     RUBBER  515 


Rs. 

Rs. 

5th  Year  . .         Superintendence 

900 

Weeding 

750 

Fencing 

50 

Contingencies 

70 

Roads,  &c.,  and  general  attention 

lOO 

1,870 

Interest  at  7  % 

Rs. 

2,109 

32,240 

Rs.  322-40  per  acre  at  end  of  fifth  year. 

Memos. — I  close  the  estimate  at  termination  of  the  fifth  year, 
as  it  is  now  generally  admitted  that  tapping  may  commence, 
according  to  growth,  between  the  end  of  fourth  and  sixth  years. 

The  estimate  is  framed  on  the  lines  of  rubber  planting  as 
ordinarily  carried  on  in  the  district  of  Matale,  and  might  serve  as 
a  guide  to  the  planting  of  rubber  in  such  districts  as  Badulla 
Valley,  Kurunegala,  Dumbara,  &c.,  districts  usually  not  heavily 
influenced  by  the  rains  of  the  south-west  monsoon. 

Felling. — The  cost  of  felling  and  clearing  both  of  forest  and 
chena  land  is  so  very  variable,  that  it  is  impossible  to  give  an 
estimate  which  would  apply  to  the  rubber  districts  generally. 

Clearing. — In  some  districts  I  have  had  chena  lands  cleared 
for  Rs.  9  per  acre  ;  and,  again,  the  felling  of  forest  will  not  be  taken 
up  by  contractors  in  some  localities  for  less  than  Rs.  25  per  acre. 

Roads  and  Drains. — The  cost  would  be  from  Rs.  5  to  Rs.  8 
per  acre  according  to  lay  of  land,  soil,  &c. 

Fencing. — Fencing  can  only  be  estimated  for  by  the  mile. 
Many  estates  or  clearings,  covering  perhaps  only  100  to  150  acres, 
would  require  3  to  4  miles  of  fencing  owing  to  established  rights 
of  way.  My  estimate  is  for  a  treble  wire  fence.  It  is  not  at  all 
certain  that  it  would  not  pay  in  cases  where  clearings  have  a 
jungle  frontage  to  put  up  two  wires  only,  say  at  i  foot  6  inches  and 
3  feet,  backed  by  galvanized  wire  3  feet  by  3  inches  mesh.  The  cost 
of  the  barbed  wire  fence  would  be  reduced  to  Rs.  50  per  mile.  The 
galvanized  wire  would  cost  about  Rs.  285  per  mile.  The  total 
cost  of  such  fencing  would  therefore  work  out  at  about  Rs.  422 
per  mile.  It  would  effectually  put  a  stop  to  the  depredations  of 
muntjak  deer,  mouse  deer,  porcupines,  and  hares,  and  those  who 
have  clearings  along  a  jungle  edge  know  what  damage  such 
animals  can  do. 

Planting. — The  use  of  basket  plants  and  shading  with  cad- 
jans  adds  about  Rs.  5  to  Rs.  6  per  acre  to  the  cost  of  planting  ; 
but  results  prove  that  this  extra  expense  is  well  repaid. 

Weeding. — This  is  an  item  which  may  very  easily  exceed 
the  estimate  I  have  given  as  regards  chena  lands.  The  first  year's 
weeding  should  not,  however,  in  any  case  cost  over  Rs.  3  per 
acre  per  month — say  Rs.  36  per  acre  for  the  year  for  the  weediest 
chena  lands.  It  may  cost  this  unless  labour  is  very  plentiful 
From  fourth  year  the  weeding  should  be  reduced  in  either  forest 
or  chena  land  clearings  to  an  average  of  75  cents  per  acre. 


5l6  PARA     RUBBER 

Superintendence. — Has  been  estimated  for  on  the  supposition 
that  the  clearing  is  being  looked  after  by  the  manager  of 
an  adjoining  property.  In  the  case  of  an  estate  of  considerable 
acreage  being  concerned,  this  item  would  be  chargeable  at  Rs.  lo 
per  acre  per  annum  all  through. 

Buildings. — I  make  no  estimate  for  factory,  superinten- 
dent's bungalow,  &c.,  though  both  would  be  required.  Super - 
ntendent's  bungalow  could  be  built  for  about  Rs.  2,000. 

It  is  useless  at  the  present  stage  of  the  industry  to  make  an 
estimate  for  a  factory,  as  the  invention  of  suitable  machinery, 
which  is  sure  to  foUow  during  the  next  year  or  two,  wiU  revolutionize 
the  curing  of  rubber.  It  would  probably  be  safe,  however,  to 
allow  at  the  rate  of  Rs.  50  per  acre  as  the  cost  of  the  building  only. 

Coast  Advances. — I  have  charged  these  as  an  ordinary  item 
of  expenditure.  It  is  only  fair  to  do  so,  as  it  is  an  item  which, 
though  slightly  varying  in  amount,  is  never  absent,  and  is  just 
as  really  a  charge  on  the  estate  as  superintendence  or  any  other 
item,  and  should  be  recognised  as  such.  The  amount  Rs.  2,400 
would  probably  be  exceeded  from  and  after  the  sixth  year  on 
tapping  operations  commencing. 


Wiltshire, 
Matale,  October  10,  1905. 


E.  GORDON  REEVES. 


Estimate  II. 
Para  Rubber  in  Central  Provinxe. 
Estimate  for  Opening  Land  and  Notes  on  Same. 

In  making  an  estimate  for  opening  land  there  are  many  things 
to  be  taken  into  consideration,  such  as  (i)  the  nature  of  the  jungle 
to  be  felled — whether  high  or  low  ;,  (2)  nature  of  soil — whether 
good  soil  with  rocks  or  hard  gravelly  soil  ;  (3)  lay  of  land — if  the 
land  is  fairly  flat  with  few  rocks  or  stones,  the  work  will  be  much 
cheaper  than  on  a  rocky  and  hUly  estate  ;  (4)  local  conditions  of 
labour — in  some  districts  the  cooly  is  paid  33  cents  per  day,  in 
others  50  cents.  Therefore,  I  should  not  think  of  framing'  an 
estimate  until  I  saw  and  examined  the  land.  The  whole  work  with 
the  exception  of  felhng  and  clearing  can  be  done  cheaper  with 
Tamil  than  village  labour. 

The  cost  of  felling  and  clearing  varies  from  Rs.  12.50  to  Rs.  20  ; 
roads  and  drains,  according  to  lay  of  land,  Rs.  7-50  to  Rs.  12,  and 
even  Rs.  20  per  acre  in  rocky  and  hilly  land,  as  blasting  and  building 
is  an  expensive  item. 

Barbed  wire  and  fencing  is  an  important  item,  and  I  have 
added  this  to  the  estimate. 

The  following  estimate  is  made  for  an  estate  in  the  Central 
Province  worked  entirely  by  village  labour.  Lay  of  land,  mostly 
on  hillsides,  with  a  fair  number  of  rocks.     Average  cost  of  labour 


PARA     RUBBER 


517 


about  40  cents  per  day. 
new  clearings. 


I  strongly  advocate  seed  at  stake  in  all 


Estimate  of  Purchasing  and  Opening  300  Acres  of  Land. 

Rs. 

I. — Purchase  of  land,  say  300  acres,  at  Rs.  50  per  acre         ..          ..  15,000 

2. — Felling,  burning,  clearing,  rooting  300  acres,  at  Rs.  15  per  acre . .  4,500 

3. — Roads  and  drains,  blasting  and  building,  at  Rs.  I2  per  acre       .  .  3,600 

4. — Lining  and  pegs,  15  ft.  by  15  ft.,  at  Rs.  1'50  per  acre       . .          .  .  450 

5. — Holing  2  ft.  by  1 5  in.  and  filling,  at  Rs.  6-50  per  acre  i  ,950 
6. — Cost  of  seed  at  Rs.  6  per  1,000,  3  in  a  hole,  at  5  cents  per  acre, 

and  planting          ..                                                       ..  1,500 

7. — Nursery  basket  plants  for  supplies,  6,000  and  upkeep     ..  150 

8. — Planting,  Rs.  i"50  per  acre. .          ..          ..          ..          ..  450 

9. — Weeding,  April  to  December,  at  Rs.  20  per  acre  . .          . .  6;O0O 

10. — Bungalow,  Rs.  2,500  ;  lines  (20  rooms)  Rs.  600  .  .          .  .  3.100 

II. — Superintendent,  Rs.  3,000  ;  Conductor,  Rs.  600             ..  3,600 

12. — Tools  and  contingencies      ..                      ..          ..          ..          ..  750 

13. — Barbed-wire  fence,  4  strands  put  8  ft.  apart,  and  erection  of 
same,  at  15  cents,  per  yard,  or,  in  round  figures,  say,  at  Rs. 
5  per  acre  (if  2-in.  wire  netting  buried  and  put  in  ground — 
and  3  strands  of  barbed  wire  and  erection,  at  Rs.  9  per  acre.) 


2nd  to  6th  year : — 

Supervision,  Rs.  3,600 

Weeding,  second  year  at  Rs.  20  per  year,  Rs.  6,000 
third  year  at  Rs.  15  per  year,  Rs.  4,500 
fourth  to  sixth  year  at  Rs.  10  per  year,  Rs.  9,000 

Upkeep  of  roads  and  drains  at  Rs.  i  per  acre,  5  years  at  Rs.  5 

Upkeep  of  lines,  bungalow,  &c.,  5  years 

Supplying  and  attending  young  plants,  5  years  at  Rs.  200 

Sundries  and  contingencies,  5  years  at  Rs.  250 . . 


1,500 

42,550 

18,000 

19.500 

1,500 
1,250 
1,000 
1.250 

Rs.  85,050 


Total  cost  of  300  acres  (Rupee  at  is.  4d.) — ^^5,670;  or  ^£18  18s.  per  acre. 
October  14,  1905.  ,       FRANCIS   J.   HOLLOW  AY. 


Estimate  III. 
First  and  Second  Years — Peradeniya  District. 


First  Year. 

Second  Year 

Rs.  c. 

Rs.  c. 

Superintendence 

10    0 

10    0 

Felling           

12     0 

— 

Lining,  1 8  feet  by  1 8  feet     . 

I     0 

— 

Pegging          

I     0 

— 

Roads  and  drains 

15     0 

I  50 

Fencing  with  barbed  wire    . 

14     0 

HoUng 

6     0 

— 

Filling  and  planting 

3     0 

— 

Plants            

I  50 

0  50 

Weeding 

10     0 

9     0 

Buildings 

8     0 

0  25 

Tools             

0  50 

— 

Contingencies 

2     0 



Supplying  and  fencing 

■  — 

2      0 

Cost  per  acre 

.Rs.84    0 

Rs.23  25 

5i8 


PARA     RUBBER 


Estimate    IV. 

First  to  Sixth  Year — Kalutara  District. 

The  following  estimate  of  the  cost  of  opening  up  Hevea 
rubber  land  is  about  the  average  for  light,  low-country  jungle 
land  in  the  Kalutara  district.  On  many  estates  the  cost  for  the 
first  six  years  works  out  at  from  Rs.  i8o  to  Rs.  200  per  acre. 


Year. 

ISt. 

2nd. 

3rd. 

4th. 

Sth.          6th. 

Rs. 

c. 

Rs.  c.      Rs.  c. 

Rs.  c. 

Rs.  c.      Rs.  c. 

Felling  and  clearing    . 

8 

0 

— 

— 

— 

—             — 

Drains 

12 

0 

— 

— 

— 

—             — 

Roads  .  . 

4 

0 

2     0 

I  50 

I   50 

10         10 

Holing  and  filling 

5 

0 

— 

—             — 

Lining  and  pegs 

2 

0 

— 

— 

— 

—             — 

Weeding 

18 

0 

16     0 

12      0 

12     0 

12     0       12     0 

Fencing 

4 

0 

2     0 

2      0 

1     0 

10         10 

Plants 

4 

0 

— 

— 

— 

—            

Planting 

I 

0 

2     0 

— 

— 

—             — 

Tools 

2 

0 

u   50 

0  50 

— 

—             — 

Superintendence 

12 

0 

5     0 

5     0 

5     0 

50         50 

Survey,  &c.,  and  con- 

tingencies 

I 

0 

0  50 

0  50 
M  50 

1     0 

10         10 

Cost  per  acre         Rs. 

73 

0 

28    0      S 

20  50 

20    0      20    0 

Es 

T 

Total— Rs.  183. 

timate  \ 

First  and  Second  Years- -Ambalangoda  District. 

First  Year. 

Second  Year. 

Rs. 

c. 

Rs.  c. 

Felling  and  clearing 

10 

0 

Lining  and  pegging 

2 

0 



Roads  and  drains    .  . 

15 

0 

I  50 

Fencing  with  barbed  wire 

5 

0 

Holing 

9 

0 



FilUng  and  planting 

7 

0 



Plants 

I 

50 

0  50 

Weeding 

12 

0 

12     0 

Contingencies 

2 

0 

I     0 

Supplying  and  fencinj 

Rs.  63 

50 

I  50 

Cost  per  acn 

Rs.  16  50 

Estimate   VI. 

First  and  Second  Year — Ambalangoda  District. 
Principal  Items  in  opening  Swampy  Land. 

First  year. 


FelUng  and  clearing 
Lining  and  pegging 
Roads  and  drains    . . 
Heaping  soil 
Fencing  with  wire  . . 
Filling  and  planting 
Weeding 
Contingencies 
Supplying,  &c. 

Cost  per  acre 


Rs.  c. 

4  o 
2     o 

30     o 

8  50 

5  o 
7     o 

24    o 

2       O 


Rs.  82  50 


Second  Year. 
Rs.  c. 


24     o 
I     o 

I  50 

Rs.  36  50 


PARA     RUBBER 


519 


Estimate  VII. 

Estimate  of  Opening  One  Acre  under  Rubber  in 
Low-country,  Ambalangoda. 

First  Year.  Rs.  c. 

Superintendence           . .          . .          . .  . .          .  .          . .          lo     o 

Costof  watering  and  rearing  plants,  per  1,000  ..          ..           20 

Felling  and  clearing      . .          .  .          . .  . .          . .          .  .           80 

Lining,  20  ft.  by  20  ft.  . .          . .          . .  . .          .  .          , .            i  50 

Holing  and  filling  in,  2  ft.  by  2  ft.  by  2  ft.  90 

Planting             . .          . .          . .          .  .  . .                                    to 

Wearand  tear  of  tools              ..          ..  ..          ..          ..           2  50 

Weeding,  per  month,  Rs.  I -50             ..  ..          ..          i8     o 

Drains    .  .          . .          .  .  . .          . .          .  .           80 

Roads     . .                                              . .  50 

Supplying         . .  o  50 

Fencing  with  barbed  wire        . .  30 

Cost  per  acre 

Second  Year. 
Superintendence 

Weeding,  per  acre  per  month,  R.  i     . . 
Supplying 
General  upkeep — drains,  roads,  and  contingencies  . . 


No  bungalow  or  lines  estimated  for  in  either  first  or  second 
year.  Cost  of  plants  or  watchman  not  taken  into  consideration, 
the  cost  of  former  being  too  fluctuating. 

In  the  foregoing  estimates  I  have  given  the  figures  as  presented 
to  me  by  my  friends.  Items  such  as  superintendence  and  interest 
are  not  always  shown,  and  the  variation  in  cost  of  felling,  clearing, 
and  weeding  is  very  great. 


.68 

50 

Rs. 

c. 

5 

0 

12 

0 

I 

0 

5 

0 

.23 

0 

Estimate  of  Costs  in  Southern  India. 

Estimate  for  Opening  500  AcreS  of  Para  Rubber  with 
Five  Years'  Expenditure. 

The  conditions  for  which  this  estimate  has  been  framed  are 
those  of  the  lowlands  of  S.W.  India,  which  is  the  part  most  suitable 
for  Hevea.     Elevation  at  or  near  sea-level.     Rainfall  80  inches 
and  upwards. 

The  purchase  of  land  is  presumably  from  private  owners. 
The  British  Government  has  very  little  land  suitable  for  sale, 
and  the  Governments  of  Travancore  and  Cothin  are  difficult  to 
deal  with. 

First  Year.  Rs. 

Purchase  of  land  at  Rs.  40  per  acre,  500  acres         .  .  .  .       20,000 

Fillingandclearingat  Rs.  I5peracre  •       ..  ..  ..         7,500 

Nurseries,  100,000  plants  at  Rs.  25  per  1,000  ..  ..         2,500 

Roads  and  drains  at  Rs.  10  per  acre . .  . .  . .  . .         5.000 

Lining  and  pegs,  iSft.  by  i8ft.  (=  130  plants  per  acre),  at 

Rs.  I  per  acre      . .  . .  . .  . .  . .  . .  500 


520 


PARA     RUBBER 


First  Year. 
Pitting,  2  ft.  by  2ft.  at  Rs.  3  per  acre 
Filling  pits  and  planting  at  Rs.  2  per  acre    . . 
Supplying  at  R.  i  per  acre     . . 
Shading  at  Rs.  4  per  acre 
Planting  shade  (dadap  stumps) ,  say 
Weeding  at  Rs.  2  per  acre  per  month — 9  months    . . 
Fencing  at  Rs!  6  per  acre 

Buildings,  etc.  ; — 
Coolie  lines 

Bungalow,  out-buildings  and  furniture 
Tools    . . 

Management : — 

Superintendent  at  Rs.  250  per  month  ;    Writer  at  Rs. 

per  month  ;  Allowances  at  Rs.  25  per  month . . 
Visiting  Agent  at  Rs.  100  per  month 

Sundries  : — 
Advances 

Medicines,  books,  stationery 
Taxes   . . 
General  contingencies 


Second  Year. 
Weeding  at  Rs.  2  per  acre — 12  weedings 
Supplies 

Digging  at  Rs.  7  per  acre 
MEinagement,  same  as  before 
Upkeep  roads  and  drains  at  Rs.  2  per  acre 
Tools,  taxes  and  general  contingencies  as  above 


Third  Year. 
Weeding  at  Rs.  1-8  annas  per  acre — 12  weedings 
Supplies 

Management  as  before 
Upkeep  roads  and  drains 
Tools,  taxes,  and  general  contingencies  as  above 


50 


Rs. 

1,500 
1,000 
500 
2,000 
1,000 
9,000 
3,000 

1.500 
4,000 
1,000 


3,900 
1,200 


1,000 
500 
500 
500 


Rs.  67,600 

Rs. 
12,000 
500 

3.500 
5,100 
1,000 
2,000 


Rs.  24,100 


Rs. 
9,000 
250 
5,100 
500 
2,000 


Rs.  16,850 


Fourth  Year. 
Weeding  at  Rs.  i  per  acre — 12  weedings 
Management  . . 
Upkeep  roads  and  drains 
Manure 
Tools,  taxes  and  general  contingencies  as  above 


Fifth  Year. 
Weeding 
Management  . . 
Roads  and  drains 

Tools,  taxes,  and  general  contingencies  as  above    . . 
Factory  and  machinery         . .         . .         , .    ^^3,000 


Rs. 
6,000 
6,300 
500 
3,000 
2,000 

Rs.  17,800 


Rs. 
4,000 
6,500 
1,000 
2,000 
45,000 


Rs.  58,500 


PARA     RUBBER 


521 


Summary 


I  St  year 
2nd  year 
3rd  year 
4th  year 
5th  year 


Rs.  67,600 
24,100 
16,850 
17,800 
58,500 


Rs.  184,800     =     Rs.  369  or  S25  per  acre. 

2nd  October,  1911.  E.    G.    WINDLE. 

Mr.  Windle  has  not  allowed  for  interest  (compound).  In- 
cluding this,  at  the  rate  of  6  per  cent.,  the  total  amount  for  the 
iive  years  is  Rs.  222,968,  which  equals  Rs.  446  or  £29  15s.  per  acre. 


Rubber  Planting  in  Malaya. 

estim.'vtes  for  opening  1,000  acres,  or  250  acres  in  each 
OF  Four  Years. 


Year. 

ist. 

2nd. 

3rd. 

4th. 

5th. 

$ 

$ 

% 

$ 

$ 

Premium  (1,100  acres)    .. 

3,300 

— 

— 

Survey  Fees 

1,100 

— 

— 

— 

— 

Rent         

1,100 

1,100 

1,100 

1,100 

I.IOO 

Felling,  Clearing,  and  Burning 

8.750 

8.750 

8.750 

8.750 

— 

Removal  of  logs  and  roots 

12,500 

12,500 

12,500 

12,500 

— ■ 

Lining,  Holing,  and  Planting    . . 

1.375 

1.375 

1,375 

1.375 

— 

Nurseries  and  Seeds 

1,300 

1,000 

1,100 

1,200 

500 

Weeding  (first  year  for  3  months) 

1,500 

4,500 

7.500 

10,500 

12,000 

Supplying,  Pests,  etc.     . . 

— 

1.250 

2.250 

2,250 

1.750 

Roads,    Drains,    Bridges,     and 

Fences 

3.500 

2,500 

2,000 

1.500 

500 

Bungalow,  Lines,  Hospital,  etc. 

5,000 

I,OQO 

2,000 

2,000 

1,000 

Upkeep  of  same  . . 

1,200 

1,000 

1,000 

1,000 

? 

Tools,  Live  Stock,  and  Vehicles, 

and  Factory 

1.500 

1,000 

1,200 

1,300 

17,200 

Medical  Charges . . 

1.500 

1.750 

2,000 

2,250 

2,250 

Superintendence,  Allowances   . . 

5.500 

6,000 

8,500 

9.500 

12,000 

Coolie  Assessments     and     Re- 

cruiting Expenses  . . 

2.500 

3,500 

4.50Q 

5.500 

7,000 

Water  Supply 

1.500 

1,500 

1,500 

1,500 

1,500 

Assessments,  Contingencies 

2,000 

1,500 

1,200 

I,2C0 

1,300 

55.125 

48,825 

Tob 

60,725 

64.425 

00  dollars 

57.100 

il— 286,2 

In  the  above  estimate  for  Malaya  I  have  estimated  for  the 
removal  of  logs  and  uprooting  of  tree-stumps  at  a  total  cost  of 
50,000  dollars  for  i,ooo  acres.  I  have  also  included  the  rent, 
premium  and  survey  fees'  for  i,ioo  acres,  out  of  which  i,ooo  acres 
can  be  planted.  Furthermore,  though  a  factory  is  included  in  the 
fifth  year,  no  account  is  taken  of  revenue,  which  should,  if  the 
estate  has  been  kept  in  order,  have  accrued  in  that  year  and  the 
fourth  year. 

The  total  cost  of  286  dollars  (£35)  per  acre  may  be  regarded 
as  high, .  but  if  allowance  is  made  for  the  extra  cost  of  European 
supervision,  erection  of  factory,  labour  and  government  assess- 
ments for  hospital,  drains  and  water  supply,  I  do  not  think  the 
amount  estimated  will  leave  a  very  big  margin.     Even  this  figure 


522 


PARA     RUBBER 


does  not  include  London   and   local   agency   charges    or  interest 
on  the  money  expended. 


Costs  of  Planting  in  Borneo. 

In  view  of  the  publicity  given  to  rubber  planting  in  Borneo, 
especially  in  the  Northern  British  territory,  an  estimate  of  costs, 
compiled  at  my  request  by  Mr.  John  Bruce,  late  Manager  of 
Sekong  Estate,  Borneo,  is  here  given.  It  will  be  observed  that 
the  costs  up  to  the  end  of  the  fifth  year  on  the  East  and  West 
coasts  are  estimated  respectively  at  315  and  318  dollars  per  acre. 
On  the  East  coast,  Mr.  Bruce  estimates  for  planting  300,  400,  and 
300  acres  respectively  in  the  first,  second,  and  third  years,  whereas 
on  the  West  Coast  he  estimates  for  opening  800  and  200  acres  in 
the  first  and  second  years  respectively. 

The  East  Coast  is  regarded  as  that  area  East  of  Marudu  Bay. 
A  launch  is  estimated  for  in  that  area  and  also  the  cost  of  keeping 
it  in  good  order  each  year. 

Mr.  Bruce  informs  me  that,  as  a  general  rule,  the  land  on  the 
East  Coast  is  better,  the  jungle  heavier,  and  the  rainfall  more 
prolonged  than  on  the  West  Coast.  He  beheves  that  five-year- 
old  trees  on  the  East  Coast  are  six  months  ahead  of  those  on  the 
West  Coast. 

British  North  Borneo. 

Cost  of  Purchase,  Opening  and  Bringing  into  Bearing 

1,000  Acres. 


First   Year. 
Cost  of  1,000  acres  of  land  at  B.N.  Borneo  Co.  rates 
Rentiicing 
Felling      . .  . .       ... 

Piling,  Clearing,  and  Burning 

Lining,  Holing,  and  Planting 

Supplying 

Plants  and  Nurseries 

Roads  and  Drains 

Fencing    . . 

Tools,  Implements,  etc 

Bridges     . . 

Office,  Stationery,  Books,  etc 

Buildings — 

Lines  for  300  and  400  Coolies 

Hospital  for  60  Patients  with  outhouses,  etc. 

Dressers'  and  Clerks'  quarters 

Office,  Store,  and  Shop 

Manager's  Bungalow  and  Furniture 

Assistant's  Bungalow  and  Furniture 
Insurance  on  Buildings  and  Launch     . . 
Recruiting,  Cost  of  importing  300  or  400  coolies,  less 

amounts  recoverable 
Transport,  Cost  of  Launch,  Upkeep,  Wages  of  Crew 
Doctor  and  Hospital,  Salary  of  Doctor,  Dresser,  Up 
keep  of  30  patients,  including  medicine,  etc. 
Weeding  .  . 

Salaries— Manager,  Assistant,  Clerk 
Agency  Fees 
Contingencies  and  Miscellaneous 


East 
Coast. 
17.142 

75 
2,400 
7.500 
1,320 

75 
1,900 
2,100 

2.332 
300 

1.200 
500 

1,500 
2.000 

1,400 

3  •500 

1,400 

627 

13,200 
7.750 

4.770 

9,000 

10,200 

1.457 
2,000 


West 

Coast. 

42,850 

200 

4,000 

7,200 

6,400 

200 

1,100 

5.600 

5.952 

1,200 

500 

500 

2.750 

2, coo 

500 

1,400 

4,530 

3,400 

218 

18,000 

3.000 

6,170 

9,000 

12,300 

1.457 
1.500 


$95,648        $141,897 


PARA     RUBBER 


523 


In  these  estimates  300  acres  are  opened  up  on  the  East  and 
800  acres  on  the  West  Coast.  Weeding  on  the  East  Coast  is  taken 
at  $250  per  acre  per  month  for  6  months  ;  on  the  West  Coast  this 
is  calculated  as  400  acres  for  3  and  400  acres  for  6  months  at 
$250  monthly,  per  acre. 


Second  Year. 

Ren  tricing 

Felling 

Piling  and  Burning 

Lining,  Holing,  and  Planting    . . 

Supplying  .  . 

Nurseries . . 

Ro'ads  and  Drains 

Fencing    . . 

Tools,  Implements,  etc. . . 

Bridges    . . 

Office,  Stationery,  etc.   . . 

Buildings,  Lines  for  100  Coolies  and  Upkeep  . . 

Insurance 

Recruiting  100  Coolies   . . 

Transport,  Launch,  Wages,  Fuel,  etc. 

Doctor  and  Hospital,  Salaries  and  keep  of  40  Patients 

Weeding  . . 

Salary  of  Manager,  ist  Assistant,  2nd  Assistant,  Clerk 

Agency  Fees 

Contingencies  and  Miscellaneous 


In  the  second  year  400  acres  are  opened  upon  the  East  and  250 
acres  on  the  West  Coast.  Weeding  is  estimated  for  the  East 
Coast  at  300  acres  for  12  months  at  $200  and  400  acres  for  six 
months  at  $250  per  acre,  monthly  ;  on  the  West  Coast  800  acres 
are  worked  at  $150  and  200  at  $250  per  acre  per  month. 


East 

West 

Coast. 

Coast. 

$ 

$ 

100 

50 

3,200 

1,000 

10,000 

1,800 

1,760 

1,600 

175 

130 

600 

200 

2,800 

1,600 

2,976 

1,480 

120 

300 

1,200 

400 

100 

100 

600 

880 

627 

228 

4,400 

4.500 

1.750 

3.500 

3            5.500 

6,170 

13,200 

17,403 

k          12,000 

12,900 

1.457 

1.457 

1, 00c 

1,000 

$63,565 

$56,695 

East 

West 

Third  Year.                                             Coast. 

Coast. 

$ 

$ 

Rentricing  . . 

75 

100 

Felling 

2,400 

— 

Piling  and  Burning 

7.500 

— 

Lining,  Holing,  and  Planting 

1,320 

— 

Supplying    . . 

175 

— 

Nurseries     . . 

600 

50 

Roads  and  Drains  . . 

2,100 

300 

Fencing 

2,232 

150 

Tools,  Implements,  etc.      . . 

100 

100 

Bridges 

1,050 

200 

Office,  Stationery,  etc. 

100 

100 

Buildings,  Upkeep 

300 

300 

Insurance     . . 

627 

228 

Recruiting  .  . 

2,200 

— 

Transport,  Launch,  Repairs,  etc. 

4.365 

4,000 

Doctor  and  Hospital,  Salaries  and  keep  of  35  patients  . 

2,770 

4,801 

Weeding 

19.500 

15,000 

Carried  forward 

$47,414 

$25,329 

524 


PARA     RUBBER 


East 

West 

Coast. 

Coast. 

$ 

$ 

47.414 

25.329^ 

12,600 

13.500 

1.457 

1.457 

1,200 

1,000 

400 

I, coo 

$  63,071 

42,286 

Third  Year. 

Brought  forward 
Salary,  Manager,  ist  Assistant  2nd  Assistant,  Clerk 
Agency  Fees  . .  . .  . .  .'. 

Contingencies  and  Miscellaneous 
Pests,  Diseases  and  Pruning 


On  the  East  Coast  300  acres  are  planted  in  the  third  year. 
Weeding  is  estimated  to  cost,  on  the  East  Coast,  300  acres  at  1/50, 
400  at  2/-,  and  300  at  2/50  dollars  per  acre,  the  last  being  for  six 
months  only  ;  on  the  West  Coast  1,000  acres  are  estimated  to  CQst 
1/25  dollars  per  acre,  per  month. 


Fourth  Year. 

Supplying 

Nurseries 

Roads  and  Drains  . , 

Fence 

Tools  and  Implements 

Bridges.  Upkeep     . . 

Stationery 

Buildings,  Upkeep 

Insurance . . 

Recruiting 

Transport,  Launch,  Fuel,  etc. 

Doctor  and  Hospital,  Salaries  aftd  keep  of  20  patients 

Weeding 

Salary    of   Manager,    ist    Assistant,    and    Assistant, 

3rd  Assistant,  and  Clerk 
Agency  Fees 

Contingencies  and  Miscellaneous 
Pests,  Diseases,  Pruning 


East 

West 

Coast. 

Coast. 

f 

f 

100 

100 

150 

— 

500 

300 

200 

200 

100 

100 

200 

200 

100 

100 

300 

300 

627 

228 

4,400 

1,200 

2,100 

4,000 

5.500 

4,801 

18,000 

12,000 

14,700 

14,100 

1.457 

1.457 

1,500 

1,000 

600 

1,500 

$50,534       $41,586 


On  the  East  Coast  weeding  is  estimated  to  cost  for  300  acres, 
$1/00,  400  acres,  $1/50,  and  300  acres  $2/00  per  acre, 
monthly  ;  on  the  West  Coast  1,000  acres  are  estimated  to  cost 
$1/00  dollar  per  acre  per  month. 


Fifth  Year. 


Roads  and  Drains  . . 

Fence 

Tools  and  Implements 

Bridges 

Office  and  Stationery 

Buildings     . . 

Insurance 

Recruiting  . . 


East 

West 

Coast. 

Coast. 

$ 

$ 

600 

400 

200 

250 

100 

TOO 

300 

200 

100 

100 

800 

500 

627 

228 

2,200 

1,000 

Carried  forward 


$4,927  $2,778 


PARA     RUBBER 


525 


Fifth  Year. 

Brought  forward 
Transport,  Launch,  Repairs,  etc. 
Doctor  and  Hospital,  Salary  of  Doctor  and  Dresser, 

and  keep  of  2  a  Patients 
Weeding 
Salary  of  Manager,  ist  Assistant,  2nd  Assistant,  3rd 

Assistant,  and  Clerk 
Agency  Fees 

Contingencies  and  Miscellaneous 
Pests,  Diseases  and  Pruning 


East 

West 

Coast. 

Coast. 

$ 

1 

4.927 

2,778 

2,000 

4,000 

4.770 

4.345 

12,000 

6,000 

15,600 

14,400 

1.457 

1.457 

1,500 

1,000 

800 

1.500 

$43,054       $35,480 


On  the  East  Coast  weeding  is  estimated  to  cost  for 
50  cents,  400  acres,  $1/00,  and  300  acres,  $1/50  per  acre, 
on  the  West  Coast  1,000  acres  are  estimated  to  cost  50 
acre  per  month. 


Sixth  Year. 

Roads  and  Drains  . . 

Fence 

Tools  and  Implements 

Bridges 

Office  

Buildings,  lines  for  50  Coolies,  upkeep,  etc. 

Insurance     .  . 

Recruiting  . . 

Transport  and  Launch 

Doctor  and  Hospital,  Salaries  and  keep  of  25  Patients 

Weeding 

Salaries  of  Manager,  ist  Assistant,  2nd  Assistant,  3rd 

Assistant,  and  Clerk 
Agency  Fees 

Contingencies  and  Miscellaneous 
Pests,  Diseases  and  Pruning 


East 

Coast. 

$ 

600 
200 
100 
300 
100 
800 
627 
4,400 
2,200 

4.770 
7,800 

15.900 

1.457 

1,000 

700 


300  acres, 
monthly ; 
cents,  per 

West 

Coast. 

? 

400 

600 

100 

300 

100 

600 

228 

1,000 

4,000 

4,800 

3,000 

14,100 

1.457 
1,200 
2,000 


$40,954         $33,885 


On  the  East  Coast  weeding  is  estimated  to  cost  50  cents,  for 
700  acres  and  $1/00  for  300  acres,  per  month  ;  on  the  West  Coast 
1,000  acres  are  estimated  to  cost  25  cents,  per  acre,  monthly. 


Seventh  Year. 

East  Coast. 

West  Coast 

Roads  and  Drains 

800 

$ 

400 

Fence 

100 

200 

Tools 

100 

100 

Bridges 
Office 

400 

lOd 

300 
100 

Buildings     . . 
Insurance    . . 

700 
627 

600 

228 

Recruiting  . . 
Transport    . . 

200 
1,500 

$4,527 

500 
3.500 

Carried  i 

orward  . 

$5,928 

526 


PARA     RUBBER 


Seventh  Year. 

East  Coast. 

4.527 
4,040 

West  Coa 

1 
5,928 

4,000 

Brought  forward . . 
Doctor  and  Hospital,  Salaries  and  Keep 
of  20  Patients 

Weeding 

Salaries  of  Manager,  ist  Asst.,  2nd  Asst., 

6,000 

3,000 

3rd  Asst.  and  Clerk 
Agency  Fees 

Contingencies  and  Miscellaneous 
Pests,  Diseases  and  Pruning 

16,200 

1.457 

1,000 

700 

14,100 

1.457 
1,200 
2,000 

$33,924 


$31,685 


Weeding  is  estimated  to  cost  50  and  25  cents,  per  acre  per 
month  on  the  East  and  West  Coasts  respectively. 


Eighth    Year. 

Roads  and  Drains 

Fence 

Tools 

Bridges 

Office 

Buildings 

Insurance 

Recruiting 

Transport 

Doctor  and  Hospital, 

1 5  Patients 
Weeding,  1,000  acres  at  50  cents. 
Superintendence 
Agency  Fees 
Contingencies  and  Miscellaneous 
Pests,  Diseases  and  Pruning  . . 


Salaries  and  Keep  of 


East  Coast. 
S 
8jo 
100 
100 
400 
100 
700 
627 
200 
2,000 

3.675 

6,000 

15,900 

1.457 

1,000 

6oo 


$33,659 

Recapitulation. 

West  Coast. 

East  Coast 

$ 

$ 

First  Year 

141,897 

95.648 

Second  ,, 
Third     „ 

56,695 
42,286 

63.565 
63,C7I 

Fourth  ,, 

41,586 

.50.534 

Fifth      „ 

35.483 

43.054 

Sixth      ,, 

33.885 

40.954 

Seventh  , 

31.685 

33.924 

Eighth   ,, 

— 

33.659 

$383,514 

$424,409 

at  Exchange  2/4=       at  Exchange 
^44.743  or;£44  15s.       2/4=£49,5i4 
per  acre.  or  ^^49  los.  per 

acre. 


Estimate  for    One   Thousand  Bouws  Rubber  in   Java. 
By   Mr.   Noel  Bingley. 

The  cost  of  opening  and  planting  up  land  in  Java  with  Hevea 
and  bringing  same  into  bearing  varies  so  largely  according  to  the 


PARA     RUBBER 


527 


character  of  the  land,  the  locaUty,  and,  most  of  all,  the  labour 
conditions,  that  it  is  impossible  to  frame  a  standard  estimate  to 
suit  the  various  conditions. 

The  following,  however,  may  be  taken  as  an  approximate 
estimate  of  cost  of  bringing  1,000  bouws  into  bearing  in  a 
district  which  is  fairly  accessible  by  rail  and  road  and  where  the 
labour  conditions  are  such  as  to  ensure  good  upkeep  from  the 
planting  to  the  productive  stage. 

(One  bouw  equals  if  acres.     One  florin  equals  1/8). 


1ST  Year — 

General  Expenditure  : 

Salaries — 

Manager 

. .  FI.300 

Assistant 

150 

Visiting  Agent  .  . 

100 

Local  Agents     . . 

100 

Native  Clerk,  etc. 

50 

900     X     12 

Fl. 

10,800 

Tools 

400 

Stable  a/c. — Purchase  2  horses 

.  .  FI.500 

Upkeep 

250 

750 

Contingencies 

3,000 

Native  Festivities 

500 

Coolie  Brokerage  .  . 

500 

New  Lines 

1,000 

Manager's  Bungalow 

5,000 

Assistants'  Bungalow 

2,500 

Office  and  Stationery 

300 

Medical 

250 

Roads  and  Bridges 

1,000 

Rent  and  Taxes    .  . 

3,000 

Clearing  250  Bouws  Rubber — 

Nurseries  and  Seed 

Fl.ioper  bouw 

Felling  and  Burning 

40       '    ,, 

Draining 

20 

Digging                  

20 

Roads  and  Bridges 

5 

Lining 

2-50 

Holing 

5 

Planting 

5 

Pests,  etc.              

250 

Fencing 

5 

W^eeding 

10 

FI.125  X  250 

FI 

31.250 

60,250 

2ND  Year — 

General  Expenditure  : 

Salaries — 

Manager 

.  .  FI.500 

I  St  Assistant     . . 

175 

2nd  Assistant    . . 

125 

Visiting  Agent  . . 

100 

Local  Agents     . . 

100 

Native  Clerks,  etc. 

50 

Fl.1,050    X    12 

ed  forward    . . 

Fl 
Fl 

12,600 

Carri 

12,600 

528 


PARA     RUBBER 


Brought  forward  . 

Fl.  12,600 

Tools 

400 

Stable — New  Horse 

FI.250 

Upkeep  . . 

350 

600 

Contingencies 

3,000 

Native  Festivities 

500 

Coolies  Brokerage 

500 

New  Lines 

1,000 

Assistant's  Bungalow 

2,500 

Upkeep  Buildings 

1,000 

Office  Stationery  . . 

300 

Medical 

250 

Roads  and  Bridges 

1,000 

Rent  and  Taxes    . . 

3,000 

Fl.  26,650 

New  Clearing  250  Bouws — 

Nurseries  and  Seed 

Fl.ioperbouw 

FeUing  and  Burning 

■           40 

Draining    . . 

20 

Digging 

20 

Roads  and  Bridges 

5 

Lining 

2-5C     .. 

Holing 

5 

Planting     .  . 

5 

Pests,  etc 

250    .. 

Fencing 

5 

Weeding     . . 

to 

FI.125  X  250 

31.250 

Upkeep— 250  Bouws  at  FI.40 

10,000 

FL67,9oo 

3RD  Year — 

General  Expenditure  : 

Salaries— 

Manager 

ist  Assistant      . . 

. .  FI.60C 
150 

,  2nd  Assistant    .  . 

150 

Visiting  Agent  . . 

Local  Ageiits 

Clerk,  etc 

150 

150 

50 

Tools 

Stable  upkeep  FI.500,  and  i  New  Horse  FI.250 

Contingencies 

Native  Festivities 

Coolie  Brokerage  . . 

New  Lines 

Upkeep  Buildings 

Office  and  Stationery 

Medical 

Roads  and  Bridges 

Rent  and  Taxes    . . 


New  Clearing  250  Bouws  at  FI.125 

Carried  forward 


Fl.1,300  X   12        Fl.15,600 

400 

750 

3,000 

500 

500 

1,000 

1,000 

300 

250 

1,000 

3,000 


Fl.27,300 
31.250 


Fl.  58,550 


PARA     RUBBER 

Brought  forward  . . 
Upkeep — 250  Bouws  at  FI.40  =  Fl.  10,000 

250         -.        „       33  =  8,750 


529 
Fi-58,55o 

18,730 


Fl.77,300 


4TH  Year — 

General  Expbnditur>  : 

Salaries — 
Managei 
tst  Assistant 
2nci  ditto 
3rd  ditto 
Visiting  Agent 
Local  Agents 
Clerk,  etc. 


Tools 

Stable — Upkeep   . . 


Contingencies 
Native  Festivities  . . 
Coolie  Brokerage    . . 
New  Lines   . . 
Assistants'  Bungalow 
Upkeep  Buildings  . . 
Office  and  Stationery 
Medical 

Roads  and  Bridges 
Rent  and  Taxes 


New  Clearing  250  bouws  at  Fl.  1 25 
Upkeep — 250    bouws     at     FI.40 
250         ..         ..  35 

250         ..         ..  30 


5TH  Year — 
General  Expenditure  : 
Salaries — Manager 
ist  Assistant  .  . 
and 
3rd 

Visiting  Agent 
Local  Agents  .  . 
eierk,  etc. 


FI.630 
225  ' 
175 
150 
150 
150 
50 

Fl.  1,550    X   12 


Fl.  18.600 
400 
700 


^'1. 1 9, 700 

Fl.3,000 

500 

500 

1,000 

2,500 

1 ,000 

300 

250 

1,000 

3.000 

Fl.  10,000 

8.750 
7.500 


Fl.32,750 
31,250. 


26,250' 


Fl.90,250 


FI.700 
225 
175 
150 
150 
150 
50 


Tools 
Stable 

Contingencies 
Native  Festivities 
Coolie  Brokerage 


Fl.i,6oo    X    12 


Fl.  19,200 

400 

700 

3,000 

500 

1,500 


Carried  iorward 


FI.25  300 


HH 


530 


PARA     RUBBER 


New  Lines  . . 

Upkeep  Buildings  . 

Office  Stationery    . 

Medical 

Roads  and  Bridges 

Rent  and  Taxes 


Brought  forward 


Fl.25,300 
2,000 
1,000 
300 
250 
1,000 
3,000 


Upkeep — 250  bouws  x  40 

250       ..      =t  35 
250       „      X  30 
250              X  25 

to 
to 

Fl.10,000 

8,750 
7,500 
6,250 

PI.  32,850 
32,500 

Fl.8,750 

7,500 

12,500 

6th  Ykar — 
Genbrai,  Expenditure  : 

Salaries 

Sundries 
Upkeep — 250  bouws  x  FI.35 
250       „      X        30 
50°       ..      X       25 

Fl.65,350 

Fl.  19,200 
13.650 

28,750 
35,000 

Factory  and  Tapping  Tools 

Fl.  19,200 
13,650 

32,850 

8,210 

Fl.96,600 

7TH  Year — 

Salaries  as  before 

General  Expenses  ditto 

Less  i  to  Revenue  %  (250  bouws 
Revenue  %) 

Fl.24,640 

Upkeep — 250  bouws  at  FI.30 
500       ,.      .,       25 

Fl.7,500 
12,500 

Fl.ig,2oo 
13.650 

32.850 

16,425 

8th  Year— 

Salaries  as  before 
General  Expenditure  ditto 

Less  to  Revenue  %  (500  boaws 
Revenue  ^ ) 

FL  44,640 

Fl.  16,425 
12,500 

Upkbkp — 500  bouirs  at  25 

Fl.28,925 

INDEX. 


Abnormal  latex  trom  Ceylon,  258-259 
Abrasion  tests,  453 
Accounts,  standardization  of,  509 
Acetic  acid,  327,  329-335,  347  ;    quan- 
tity necessary,  329-330,  334  ;  how  to 
determine  quantity,  331-332  ;    time 
necessary,    330,    333 ;    comparative 
coagulating  power,   348  ;   effects  of 
excess,   334  ;    effect  on  strength  of 
rubber,  350  ;  effect  on   quantity  of 
protein,  334  ;  in  smoke,  393 
Acetone  as  coagulant  347,  350 
Acids  in  coagulation,  325-335,  347,  348, 
350,  354-355,  442,  447.  450  ;   adsorp- 
tion, 355  ;     effect  on  quality,  350, 
355,  442,  447  ;    and  tackiness,  447  ; 
why  they  should  be  used,  333-334  ; 
removal  by  washing,  354-355  ;   tests 
for,  in  rubber,  450 
Acid  potassium  tartrate,  348 
Acreage,  Africa,  30,  45  ;    Angola,  40  ; 
Ashanti,   41  ;      Brazil,   45  ;      British 
Guiana,  43  ;    British  North  Borneo, 
37  ;     Burmah,  32.  45  ;     Cameroon, 
39  ;    Central  America,  44  ;    Ceylon, 
30,  31,  34,  35,  45  ;  Cochin  China  and 
Annam,    35  ;      Dutch   East   Indies, 
45  ;     F.M.S.,  32,  33,  34  ;     German 
East  Africa,  40  ;     Gold  Coast,  40  ; 
Hawaii,  38  ;    Java,  36  ;    Johore,  32, 
33,  34  ;    Kedah,  33,  34  ;    Kelantan, 
34  ;       Liberia,    40  ;       Malacca,    34  ; 
Malaya,  32,  33,  34,  35,  45  ;     Negri 
Sembilan,  32,  33  ;    New  Guinea,  37  ; 
Nigeria,      40 ;        Nyassaland,      42  ; 
Pahang,     32,     33  ;        Penang,     34  ; 
Perak,    32,    33  ;       Philippines,    39  ; 
Province  Wellesley,  34  ;  Queensland, 
37  ;    Samoa,  38  ;    Selangor,  32,  33  ; 
Seychelles,  39  ;     Siam,   35  ;     Singa- 
pore, 34  ;     South  India,  31,  32,  45  ; 
Straits    Settlements,     32,     33,     34  ; 
Sumatra,  35,  36 ;  Surinam,  44 ;  Trin- 
idad and  Tobago,  43  ;   Uganda,  41  ; 
West  Indies,  42,  43,  45  ;  World,  45 
Actinic  rays,  effects  on  rubber,  446 
Adhesion  tests,  45a 
Adsorption  of  acids,  355 
Africa — acreage,   39-42,   45  ;      climate 
and  rainfall,  73-75  ;    rate  of  growth 
in,  88-90  ;    as  rubber  producer,  46 ; 
exports,  4-5 
Age    of    trees,    and    growth    of    root 
system,    98-99  ;        and    growth    in 
height  of  stem,  .78,  79,  82,  83,  87,  89, 
90,   91,   92  ;      and  growth  in  girth 
{see  Girth,  Stem,  Rate  of  Growth)  ; 
and  growth  of  foliage  crown,  79,  97- 
98  ;      influence  on  rate  of  growth, 
93-94  ;    minimum,  for  tapping,  224- 
227, 228  ;  on  Amazon,  265  ;  and  qual- 
ity of  rubber,  222-223,  225-227,  419 


Agglutination  of  latex,  347 

Agrotis,  493 

Albizzia  (Dadaps),  103,  123,  128,  137, 

146,  175-176.  178,  496,  497.  501 
Alcohols  in  coagulation,  328,  347 
Alkalies,  in  coagulation,  344,  347  {see 
Ammonia)  ;    action  on  rubber,  440, 
441-442  ;    and  tackiness,  447 
Allagar,  yield,  276,  280 
Alstonia,  46 
Alternate-day  tapping,    234-240,   243- 

249,  256 
Amazon.  See  Age  of  trees  ;  Coagula- 
tion ;  Climate  ;  Collection  ;  Cups  ; 
Cuts,  number  of ;  Effects  of 
Tapping ;  Estrada ;  Frequency  of 
Tapping  ;  Girths  ;  Incision  ; 
Latex ;  Methods  of  Tapping ; 
Resting  trees  ;  Smoking  ;  Tapping  ; 
Rainfall ;  Soils ;  Trees ;  Wound 
response ;  Yields 
Amazon,  spacing  of  trees,  264  ;  parents 

of  plantation  trees,  29 
America     as    rubber    producer,     46 ; 

plantations  in,   6 
Ammonia,  309,  319,  321,  333 
Analyses   of   plantation   rubber,    225- 

226,  428-429  ;    other  rubbers,  430 
Anglo-Malay,  yield,  279-280 
Anglo-Sumatra,  yield,   297 
Angola,  acreage,  40 
Antiseptics  in  rubber,  319,  320,  321, 
327,    328,    340-341.    372-373.    413. 
445-446,447   {see  Creosote,  Folrma- 
lin.  Disinfection) 
Apocynaceae,  46 
Arbela,  501 
Arsenate  of  lead,  490 
Arsenic-salt-horsedung  mixture,  494 
Arsenic  and  sulphur  mixture,  500 
Artificial  rubber,  468-469 
Artocarpus,  47 
Asclepiadaceae,  47 
Ash  in  latex,  316,  317,  319  ;   in  rubber, 

225,  226,  258,  428-429,  430,  441 
Ashanti,  acreage,  41 
Asia  as  rubber  producer,  46 
Astacus,  495 

Atmospheric  pressure  and  yields,  307- 
308 

Bacteria  and  tackiness,  446 

Bagan  Serai,  yield,  275 

Bakap,  yield,  275 

Balgownie,  yield,  277 

Bamboo  pots,  1 1 1 

Bananas,  100,  loi,  304 ;  cultivation,  145 

Bandar  Sumatra,  yield,  297,  298 

Banteng,  yield,  275,  276 

Bark— thickness  of ,  179,  261 ;  rate  of  ex- 
haustion, 240  ;  effects  of  repetitional 
stripping,  250-251   {see  Cortex) 


533 


INDEX. 


Bark  shavings,  thickness  of,  243-249  ; 
rubber  from,  309-310  ;     maceration 
of,  356 
Bark,  renewal,  212,  213,  229,  232,  241 
242,251,256;  rate  of,  212,  213,  232, 
241-242,      251  ;     eSect  of     tapping 
frequency  on,  241  ;  renewed,  thick- 
ness of,  241-242 ;  when  to  tap,  242  ; 
quality  of  rubber  from,  256 
Barrydo  knife,  190,  246,  247,  248,  249 
Basal  tappi^ig  of  young  trees,  219,  224, 

228    {see  Basal  V  or  Y) 
Basal  V  or  Y,  195-196,  202,  203,  211, 

212,  243, 244,  245,  246, 247, 248,  249 
Basket  plants,  109,  iio-iii 
Bassia,  49 

Batak  Rabit,  yield,  275,  276 
Batu  Caves,  yield,  275,  277,  280 
Batu  Tiga,  yield,  276,  281,  282 
Batu  Unjor,  yield,  273,  276,  277,  279, 

281,  282 
Beddewella,  yield,  289 
Bees,  492 

Beetles,  492,  493,  495.  501.  504-505 
Bertram's  smoker  coagulator,  394 
Beta  knife,  184-185 
Biffen's  centrifugal  machine,   335 
Biscuits,    334-335.    343.    354.   403-404. 

416,  419,  428,  429 
Bi-weekly  tapping,  235 
Block  planting  and  disease,  485 
Block  rubber,   373,   406-407,   407-408, 
416,  418,  425,  428  ;   presses,  408-409 
Bolivia,  263,  270 
Boots    and    shoes,    plantation    rubber 

for,  420 
Bordeaux  mixture,  488-489,  492,  496, 

497 

Borers,  501 

Borneo,  climate,  71-72  ;  acreage, 
37,  45  ;  rate  of  growth,  87,  88  ; 
yields,  299  ;  tapping  practices,  249  ; 
cost  ot  planting,  315-319 

Botryodiplodia  {see  Dieback) 

Bowman  and  Northway's  knives,  187- 
188,   248 

Brachytrypes,  494 

Branding  of  rubber,  410;  Shaw'spress, 
410 

Brazil,  exports  from,  3-13  ;  future 
supplies  from,  8  ;  cost  of  collection, 
8  ;  proposals  for  improving  in- 
dustry, g-ii  ;  equivalent  acreage, 
12,  18;  value  of  rubber,  18-20; 
seeds  sent  from  East  to,  29  {see 
Amazon  and  Fine  hard  Para) 

Breuil's  Dynamometer,  454 

Bridge's  washing  machines,  358,  359, 
366 ;  friction  clutch,  364-366 ;  vacuum 
drier,  387  ;  blocking  press,  408-409 

British  East  Africa,  42,  75 

British  Guiana,  acreage,  43  ;  climate, 
76-77  ;  soils,  165 

Brosimum,  48 

Brown  root  disease,  504 


Buffers,  plantation  rubber  for,  420 
Bugs,  plant,  493-494,  495 
Bukit  Rajah,  yield,  276,  277,  288 
Burgess,   device  for  measuring  girth, 

95-97  ;      knife,    192-193,    248,    249  ; 

and  washing  machines,  355 
Burmah,  acreage,  32  ;    rate  of  growth, 

82  ;    yields,  301  ;    analysis  of  rubber 

from,  429 
Burn-off,  in 
Burrs,    490-491 

Cabooky   soils  in  Ceylon,  153 

Cacao,    loi,    102,    103,    128,    135,    138, 

139,    147,   303,   304,   308,   482,   483, 

495.  496,  504  ;    cultivation  of,  147 
Cachar,  yield  in,  296 
Cajanus,  174 
Cake  from  seeds,  474 
Calcium  chloride  as  drying  agent,  375 
Caledonia,  yield,  306 
Calendering,  458-459 
Callicratides,  493 
Calotropis,  47 
Cambium,  54,  55 

Cameroon,  acreage,  39  ;    yields,  300 
Camphor,  497  ;    cultivation,  146 
Canker,  495-496.  498 
Caoutchouc,  reduction  in  tapping,  257, 

258  ;    characters,,  316-317,  432,  448  ; 

molecular  weight,   346  ;    amount  in 

plantation     rubber.     428-429,     430 ; 

estimation  of,  431 ;     formation  of  in 

tree.  57-58 
Carbolic  acid,  328,  329,  340,  447,  491 
Carbolineum,  489 
Carbon  bisulphide,  491,  499 
Carbonic  acid  gas  as  coagulant.  3 28 
Carey  estate,  yield,  275 
Carissa,  49 

Carpodinus,  6.  46.  48,  49 
Cassava  {see  Tapioca) 
Cassia.  130 . 
Castilloa,   2,   6,   7,    12,   27.   28,   36.   37, 

38,  39,  40,  43,  45.  47.  49,  57,  58,  59. 

102,  135,    139  ;     latex,    325,    346 ; 
rubber,  analysis,  433,  437 

Castlefield.  yield,  275,  276,  277 
CastJewood,  yield,  280 
Catch-crops,    in    Ceylon,      loi,      138  ; 
Malaya,    100,    139 ;    Sumatra,    102- 

103,  139;    Java,  loi,  139;    cultiva- 
tion, 140-146   {see  Intercrops) 

Caterpillars,  495,  501 
Cater-Schofield  knife,  186-187 
Caucho,  2,  3,  4.  426 
Ceara,  6,  7,  12,  17,  28,  36,  37,  38,  39, 

40,  41,  42,  45,  46,  48,  49    I02,  139, 

430  ;    analyses  of  rubber,  433,  441 
Censuses  of  trees,  80,  94  ;    method  of 

taking,  94 
Central  America,  acreage,  44 
Centrifugal  separation  of  rubber,  214, 

319;    machines,  335-339  ;    strainers. 

322-323 


INDEX. 


533 


Cercospora,  492 

Ceylon,  Hevea  introduced,  26 ; 
acreages,  30,  31,  34,  35,  45  ;  climate, 
67;  30113,100-101,151-158;  water- 
level,  307  ;  rate  of  growth,  78-81, 
101  ;  inter  and  catch  crops,  loi, 
138,  139 ;  exports,  15  ;  distribu- 
tion of,  16  ;  estimated  future  output, 
15-16;  first  recorded  yields,  287; 
yields  from  young  trees,  287-288  ; 
from  old  trees,  288 ;  from  trees  of 
definite  ages,  289-291  ;  per  acre  and 
per  tree,  291  ;  past  yields  per  acre, 
292  ;  yields  in  Matale  district,  292  ; 
in  Uva,  292-293  ;  in  Kelani, 
Kalutara,  Ambalangoda,  Rayigam, 
etc.,  293  ;  in Gikiyanakanda,  294  ;  in- 
crease in  yield  from  estates,  294-295 ; 
prospective  increases  from  certain 
properties,  295  ;  analysis  of  rubber 
from,  428-430 ;  tapping  practices, 
245-248;   cost  of  planting,  513-519 

Ceylon  (Para),  yield,  295 

Ceylon  T.P.,  yield,  294 

Changkat  Salak,  yield,  275 

Chemical  agents,  action  on  rubber, 
441-442  ;    chemical  tests,  456-457 

Chemical  analysis  of  rubber,  451 

Chemical  and  physical  properties  of 
rubber,  428-457  ;  relationship  be- 
tween, 431-432 

Chemical  causes  of  tackiness,  447 

Chemical  coagulants,  345,  347,  350 ; 
advantages  and  disadvantages,  332- 

333 
Chemistry,  latex.  315-320;   of  rubber, 

346 

Chersonese,  yield,  276 

Chillies,  cultivation,  144 

Chilling  of  rollers,  358 

Chisel,   carpenter's,    183 

Chonemorpha.   46,   49 

Chula  heater,  383-385,  398 

Cicely,  yield,  273,  279,  280 

Cinchona,  139,  254,  482,  496 

Cingala,  495 

Circle-weeding,  128,  130 

Circumference  of  trees  (see  Girths) 

Citric  acid,  348 

Citronella,  loi,  138,  139  ;  cultivation, 
141 

Clean  weeding,  100,  128-130,  178 

Clearing,  111-113 

Climate,  on  Amazon,  65  ;  Africa,  73-75  ; 
British  Guiana,  76-77  ;  Borneo, 
71-72  ;  Ceylon,  66-67  ;  Cochin- 
China,  72  ;  Fiji  Islands,  72  ;  Java, 
70-71  ;  Malaya,  68-70 ;  New 
Guinea,  72  ;  Philippines,  73  ;  Samoa, 
73  ;  Seychelles,  72  ;  Sumatra,  70  ; 
Surinam,  77 ;  West  Indies,  75-76 

Clitandra,  6,  46,  48,  49 

Close  planting,  1 19-120,  122-123,  3°^ 

Coagulation,  meaning  of  term,  345  ; 
theory  of,  344-351,  439-440  ;   phases 


o*.  347  ;  proteins  in,  318-319,  322, 
344-345  ;  effect  on  structure  of 
rubber,  348  ;  on  strength,  349-351  ; 
centrifugal,  319,  335-339.  344  '•  elec- 
trical, 335,  339  ;  by  heat,  320,  325- 
326,  327,  344,  350  ;  natural,  325,  353  ; 
by  chemicals,  345,  347,  350  ;  ad- 
vantages and  disadvantages,  332- 
333  ;  by  acids,  347,  348,  350  (see 
Acetic  acid)  ;  by  salts  347,  348, 
350  ;  by  mixtures,  328,  347,  348,  350 ; 
by  plant  juices,  326-327  ;  acetone, 
347  ;  by  alcohols,  347  ;  carbonic 
acid,  328;  corrosive  sublimate,  328; 
cream  of  tartar,  328  ;  formic  acid, 
327-328,  333  ;  hydrofluoric  acid, 
329  ;  sulphuric  acid,  328  ;  tannic 
acid,  328  ;  acetic  acid  (see  Acetic 
acid)  ;  by  smoking  (see  Smoke)  ;  on 
Amazon,  267,  393  ;  in  field,  339  ; 
in  bulk,  334-335  ;  advantage  of 
rapid,  331  ;  imperfect  as  cause  of 
tackiness,  447-448 

Coagulants,  proprietary,  329 

Coagulator,  spray,  335 

Coagulinc,  329 

Coalescence,  346,  347 

Coca,  139,  496  ;    cultivation,  146 

Cochin-China,  acreage,  35  ;  climate, 
72  :    rate  of  growth,  88  ;    yields,  301 

Cochrane's  heating  apparatus,  383 

Cockchafer,  492,  504-505 

Cockerill's  electrical  coagulator,  339 

Coconuts,  100,  138,  491,  497 

Coffee,  100,  loi,  102,  103,  128,  136, 
138,  139,  159,  303,  304,  305,  482, 
484,  496,  497  ;    cultivation,  147-148 

Cold,  action  on  rubber,  443 

Collecting  cups  and  spouts,  215-217  ; 
on  Amazon,  261,  267 

Collection  of  latex,  261  ;  daily  tasks, 
508  ;     on  Amazon,  194,   260-271 

Collet's  knife,  186 

Collins  brings  seeds  to  Kew,  25 

Colour  of  rubber,  319,  416,  421-422  ; 
grades,  412-414  ;  method  of  im- 
proving, 342-343  ;  discolouration  oi 
biscuits,  343 

Colouring  of  latex,  461 

Comoeritis,  501 

Compass  tapping,  212,  234 

Compositae,  47 

Composition  of  latex,  316-317 ;  of 
plantation  rubber,  225-226,  415-416, 
428-430  ;  of  fine  hard,  340  ;  of  other 
rubbers,  430 

Compounding  of  rubber,  463-464 

Compression  of  rubber,  444  ;  tests,  453 

Congo  Free  State,  4,  5,  10,  11,  12; 
yields,  300-301 

Consolidated  Malay,  yield,  276,  277, 
278,  284 

Continuous  treatment  of  Da  Costa 
and  Bridge,  402 

Copper,  action  on  rubber,  442 


534 


INDEX. 


Copper,  sulphate  of,  488,  489,  491 

Corrosive  sublimate,  as  coagulant,  etc., 
340,  348,  491 

Cortex   (or  bark),  functions  of,   250  ; 

anatomy  of,  54 
Corticium  {see  Pink  disease) 
Costs  of  planting,  estimated,  Ceylon, 
513-519;       South    India,    519-521; 
Malaya,  521-522  ;    Borneo,  522-526  ; 
Java,  526-530 

Cost  of  production,  506-512  ;  varia- 
tions in,  506  ;  influence  of  labour 
on,  507-508  ;  and  other  factors,  508  ; 
proportions  of  cost  on  estate,  508- 
509;  principal  costs  itemised,  510  ; 
form  of  accounts,  509;  in  Ceylon,  507, 
510-511  ;  in  South  India,  510-511  ; 
in  Malaya,  507,  509,  510,  511-512  ; 
in  Sumatra,  510-51 1 

Cotton,   cultivation,    143 

Cover  plants,  129,  130 

Cream  of  tartar  in  coagulation,  328 

Creosote,  327,  333,  372-373,  39b,  400  ; 
generator,  Sutton's,  398 

Crfipe,  354,  374,  418,  425,  428  ;  pre- 
paration, 334,  404-405  ;  machines, 
356-359 

Cresol,  340,  393  {see  Creosote) 

Crickets,  494 

Crop,  percentages  of  grades  m,  310-31 1 

Cross  brings  seedlings  to  Kew,  26 

Crotalaria,  129,  130,  131,  174,  175,  177, 
178,  496 

Cryptolepis,  47 

Cryptostegia,  6,  47,  48,  49 

Cultivators,   134 

Cups,  collecting  {see  Collecting  Cups) 

Cuts,  number  to  inch,  207-209,  243- 
249  ;  number  per  tree  on  Amazon, 
262-263  •  direction  of,  205  ;  paring 
upper  edge,   198,   205-206 

Cuttings,  propagation  by,  105 

Cutworms,  493 

Cyanchum,  47 

Da  Costa,  smoker  coagulator,  395-396  ; 

continuous  treatment,  402 
Dadaps  {see  Albizzia) 
Daily  tapping,  234-238,  239-240,  243- 

249,256 
Daily  tasks,  207,  508 
Dangan,  yield,  290 
Darkening  of  rubber  {see  Colour) 
Deli  Moeda,  yield,  297 
Depolymerisation,  448 
Derr5''s  smoker  coagulator,  394 
Desmodium,  130,  174,  178 
Deviturai,  yield,  290,  291 
Dickson's  smoker  coagulator,  396 
Dieback,  483,  491-492,  493,  497-498 
Diplodia  {see  Dieback) 
Diplorhynchus,  46 
Directuseof  latex,  460-462  ;  feasibility, 

461-462  ;   of  plantation  rubber,  423- 

424 


Direction  of  cuts,  205 

Disc  hari'ows,  133-134 

Discoloration  of  rubber,  343 

Diseases  and  pests,  482-504  ;  and 
protective  belts,  483-484  ;  and  inter- 
crops, 136-137  ;  and  mixed  products 
(block  planting) ,  484-485  ;  specific 
hosts,  482-483  ;  control,  485  ;  of 
seeds,  491  ;  nursery  plants  and 
stumps,  491-494  ;  leaves,  494-495  ; 
fruits,    495  ;   stem,    495-502  ;     root, 

502-505 

Disuse  of  rubber,  470 

Distance  in  planting,  in  different 
countries,  1 15-123  ;  and  rate  of 
growth,  94,  98,  99,  118-119  ;  where 
intercrops,  139-140 ;  original  and 
permanent,  121  ;  distance  required 
by  tapped  trees,  120-121  :  and 
yields,   305-307 

Distance  between  tapping  lines,  208-209 

Dixon's  knife,  189 

Dominica,  acreage,  43 

Doranakande,  yield,  290 

Dragonflies,  493 

Drainage,  102,  114 

Drip-tins,  214-215,  231,  321 

Drives  in  factories,  363-366 

Drought  and  tapping  {see  Dry  season) 

Dry  season  and  tapping,  230-233,  308  ; 
and  yields,  311-314 

Drying  of  rubber,  374-390  ;  by  ex- 
posure in  open,  374  ;  in  coid  air 
currents,  374-375  ;  in  hot  air,  375- 
376 ;  vacuum,  385-389  ;  Michie- 
Golledge  process,  389  ;  use  of 
refrigeration,  389-390  ;  with  calcium 
chloride,  ^75  ;  temperatures.  375- 
376,  384-386,  388 

Dutch  Guiana  {see  Surinaun) 

Dyera,  48,  49,  50  {see  Jelutong  and 
Pontianak) 

East  Africa,  climate,  75 

Eastern  Produce,  yield,  295 

Ecdysanthera,  47,  49 

Effects  of  tapping,  250-259  ;  on  plant 
reserves,  251  ;  exposure  to  attack 
252  :  pricking,  252-254  ;  on  per- 
iodicity, 254  ;  on  seeds,  255 ;  on 
growth,  255  ;  on  j-ields,  255-256 ; 
on  quality,  256-257  ;  on  caoutchouc, 
etc.,  in  latex,  257-258 

Elastic  thread,  plantation  rubber  for, 
420 

Electrical  coagulation,    335-339 

Elevation,  and  growth,  67-68,  79-80. 
82,  93  ;  and  yield,  303 

Elongation  at  break,  350-351 

Enzymes,  318-319,  342,  447 

Eow  Seng,  yield,  277 

Eriodendron  {see  Kapok) 

Erythrina,  103,  104,  146 

Estimated  outputs,  Malaya,  14-15  ; 
Ceylon,  16 


INDEX. 


535 


Estrada,    number   of   trees   in,    263 ; 

distances,  264  ;  area,  264 
Eugenia,  137 
Eumyces,  495 

Euphorbia,  12,  46,  48,  49,  57,  58,  436 
Evening  tapping,  233-234 
Excision  versus  incision,  203-204,  251 
Exports,    Brazil,    3-4 ;     Africa,    4-5 ; 

Malaya,  14  ;   Ceylon,  15 

F.M.S.,  acreage,  32,  33,  34 ;  yields, 
285-286 

F.M.S.  Co.,  yield,  273,  275-277,  279, 
281,  282,  284,  285 

Factories,  376-383 ;  site,  376-377  ; 
types,  377 ;  sizes,  377-380 ;  one- 
storey,  378  ;  two-storey,  378-381  ; 
curing  section,  380-381  ;  materials 
used  in  construction,  381-382  ;  timber 
in,  382-383  ;  floors,  382  ;  light  and 
windows,  382 ;  heating  apparatus, 
383  ;  ventilation  and  fans,  378,  382, 
385  ;   output,  380  ;   central,  401-402 

Farrier's  knife,  184,  243-245,  249 

Fasciations,  491 

Federated  Selangor,  yield,  284 

Felling  jungle,  in 

Fencing,  113 

Ferments  (see  Enzymes) 

Ficus,  6,  7, 12,  36,  37,  38,  40,  42,  44,  45, 
47,  48,  49,  50,  104,  139,  194;  latex, 
325  ;  analysis  of  rubber,  '430,  433 

Fiji  Islands,  cultivation  in,  38 ;  climate 
72-73  ;  rate  of  growth,  88 

Filling,  holes,  115 

Filter  beds  and  presses,  367-368 

Fine  hard  Para,  compared  with  planta- 
tion rubber,  415-418,  420,  422,  425, 
426,  432  ;  preparation,  267,  393  ;  ex- 
ports, 3-4 

First  tappings  and  tacky  rubber,  222- 
223 

Fittings  system,  194,  240-241,  245,  249, 

251 
Five-day  tapping,  239-240 
Flake  rubber,  405 
Flooding  on  Amazon,  65,  150-151 
Flower,  periodicity,  and  tapping,  229- 

230 
Foliage  crown,  rate  of  growth,  97-98  ; 

diameter,  8g,  306 
Foliar  periodicity,   52,   140,   311-313  ; 
tapping  during,  229-233  ;    effect  of 
tapping  on,  254  ;   and  crops,  311 
Fomes,   136-137,  502-504 ;    fructifica- 
tion,   502 ;     percentage   of   deaths, 
503  ;      conditions     affecting,     503 ; 
remedies,  503-504.  (see  Root  disease) 
' '  Force  of  thumb, ' '  449-450 
Forest  belts  (see  Protective  belts) 
Forest  cultivation  for  Hevea,  112,  114 
Forked  trees,  growth  of,  124-126,  229 
Formalin    (formaldehyde),    319,    321, 
337.  340.  393.  413.  416;    effect  on 
rubber,  322,  329,  333 


Formic  acid,  327-328,  333,  348 

Forms  of  rubber,  403-410 

Forsteronia,  46,  48,  76 

Four-day  tapping,  239-240 

Fractions  of  pound  in  cases,  412 

Frequency  in  tapping,  234-241,  256- 
258  ;  and  composition  of  latex,  236, 
239;  and  lowering  of  quality  of 
rubber,  256-258  ;  and  bark  renewal, 
241  ;  practice  in  East,  243-249  ;  on 
Amazon,  266 

Freezing,  of  latex,  319  ;  of  rubber,  351 

Friction  clutches,  363-366 

Fruiting  season,  65  ;  and  tapping,  229- 
230 

Full  herring-bone,  198-199,  201-203, 
205,  243-246,  248 

FuU  spiral,  199-200,  201,  202,  203,  245 

"Fumero"  smoker  coagulator,  397 

Fungi  (see  Diseases) 

Fungicides,  488-489 

Funtumia,  6,  7,  12,  27,  28,  37,  38,  40, 
41,  42,  43,  45,  46,  48,  49,  50,  58,  194, 
299  ;  latex,  326,  346,  350  ;  rubber, 
350-351,  429,  441 

Fusicladium,  498 


Gambler,  cultivation,  141 

Gapis,  yield,  282-283 

Gases,  absorption  by  rubber,  443 

Gearing  in  factories,  363-366 

General  Ceylon  R.  and  T.,  yield,  289- 
290 

German  East  Africa,  acreage,  40 

Germination  of  seeds,   108 

Gikiyanakanda,  yield,  294 

Girth,  increase  per  acre,  94  ;  and  yield, 
306-309  ;  minimum  for  tapping,  224, 
227-228  ;  of  trees  tapped  on  Amazon 
224,  264-265  ;  instruments  for 
measuring,   95-97 

Glsosporium,  498 

Glen  Bervie,  yield,  298 

Glendon,  yield,  290 

Glenbum,  yield,  296 

Glenshiel,   jrield,    275-276 

Golconda,   yield,   278-279 

Gold  Coast,  acreage,  40  ;  climate,  74  ; 
rate  of  growth,  89-90  ;  yields,  299- 
300  ;   analysis  of  rubber  from,  429 

Golden  Hope,  yield,  279-280 

Golledge's  knife,  185 

Gouge,  184,  243-246 

Grades,  percentage  in  crop,  3 10-3 11 

Grading  of  plantation  rubber,  4 10-4 11 

Grand  Central,  yield,  289,  290,  295 

Grasshoppers,  494 

Green  manuring,  173-178 

Grenada,  cultivation  in,  43  ;  chmate, 
76  ;  rate  of  growth,  gi ;  soils,  165 

Grevillea,   146 

Grooving  in  rollers,  356,  357,  359 

Ground-nuts,  loi,  174;  cultivation, 
142 


536 


INDEX. 


Growth,  rate  of,  78-99.  227  ;  effect  of 
intercrops,  304-305  ;  effect  of 
tapping,  255  ;  and  ultimate  yields, 
303-304  ;  best  growing  period,  306  ; 
and  planted  distance,  94,  98-99 ; 
and  elevation,  79-80,  82,  93  ;  in- 
fluence of  age  on,  93-94  ;  of  foliage 
crown,  97-98  ;  of  root  system,  98- 
99  ;    and  yields,  303-304 

Grymmogryllus,  494 

Guayule  (Parthenium),  6,  47,  48,  469 

Guiana,  British  {see  British  Guiana)  ; 
Dutch  {see  Surinam) 

Guiguet    machine,    360 

Gula  Kalumpong,  yield,  276,  279 

Gums  in  latex,  317,  318 

Habit  and  jdeld,  105 

Half  herring-bone,  198-199,  202,  203, 
211-212,    243-249 

Half-spiral,  201,  243-244,  246,  247 

Hancornia,  46,  48  ;   rubber,  433 

Harpeuden,  yield,  278 

Hawaii,  acreage,  38  ;  '  rate  of  growth, 
88  ;  soils,  164  ;  manuring  experi- 
ments, 166,  171-172 

Hawthorne,  yield,  296 

Heat,  effect  on  rubber,  351,  442-443  ; 
and  tackiness,  447  ;   coagulation  by, 

325-327.  344.  350 

Heating  apparatus  in  factories,  383-385 

Height  of  tapping,  218-223 

Heights  of  trees,  78,  79,  82,  83,  87-92 

Helminthosporium,  492 

Herring-bone,  198-199  {see  Full  herring- 
bone and   Half  herring-bone) 

Hevea,  other  species,  i,  12,  28,  44,  50- 
52 

Hevea  brasiliensis,  conditions  on 
Amazon,  60,  61,  65,  66,  149,  150-151  ; 
botanical  characters,  50  ;  bringing 
from  Amazon,  25  ;  sending  to  East, 
26-29 

Hexagonal  planting,  116 

High  tapping,  218-223 

Highlands  and  Lowlands,  yield,  276- 
281,  306 

Holing,   III,   115 

Holloway's    knives,   185 

Huber  knife,  192 

Humidity  and  tapping,  230-233,  308 

Hydrochloric  acid,  347,  348 

Hydrofluoric  acid  as  coagulant,   329, 

333 
Hymenochoete,  504 
Hymenolopus,   46 
Hymenoxys,  47,  48 
Hysteresis,     452-454 ;  Schwartz's 

machine,  453 

Igalkande,  yield,  291 

Ingredients  in  rubber  goods,  463-464 

Improved  low-grade  rubbers,  469 

Inch  Kenneth,  yield,  276 

Incision  method,  194,  203-204,  aji,  a6i 


India,  South,  acreage,  31,  32,  45 ; 
climate,  67-68  ;  rate  of  growth,  81- 
82  ;  soils,  158  ;  intercrops,  loi,  138; 
yields,  295-296  ;  practices  on  estates, 
249  ;  analysis  of  rubber  from,  428- 
429  ;  costs  of  planting,  51Q-521 

Indian  corn  (see  Maize) 

Indigo  (Indigoera),  100,  128,  139,  174, 
178,  304  ;   cultivation,  146 

Insects  {see  Diseases  and  pests) 

Insecticides,  489-490 

Intercrops,  in  different  countries,  100, 
138-139  ;  and  planted  distance,  123, 
139-140  ;  and  weeds,  128  ;  advan- 
tages, and  disadvantages,  136;  finan- 
cial considerations,  137  ;  effect  on 
diseases,  136-137;  cultivation,  146; 
effect  on  yields,  304-305 

Ipecacuanha,  cultivation,  141 

Ivory  Coast,  climate,  73  ;  rate  of 
growth,  90 

Jacks  for  stumping,  112 

Jak, 137 

Jamaica,  Hevea  in,  43  ;  climate,  76 ; 
rate  of  growth,  91  ;  soils,  165 

Java,  acreage,  36  ;  climate,  70-71  ; 
rate  of  growth,  85-86  ;  catch  and 
intercrops,  loi,  139  ;  soils,  162-163  ; 
water-level,  307  ;  methods  of  cultiva- 
tion, 101-102  ;  tapping  practices, 
249  ;    yields,  298-299 

Jebong  knife,  184,  243-245,  249 

Jebong,  yield,  281 

Jelutong,  436-437  (see  Pontianak  and 
Dyera) 

Jementah,  yield,  276 

Jeram,  yield,  275 

Johore  knife,  104 

Johore  State,  acreage,  32,  33,  34 ; 
annual  yields,  285 

Jugra,  yield,  273,  276-281 

K.L.  Coagulator,  337-338 
Kalutara  R.  Co.,  yield,  289 
Kalutara  R    Plantations,  yield,   289- 

290 
Kapar  Para,  yield,  276 
Kapok,  102,  137,  139 
Kedah,  acreage,  33-34  ;    annual  yield, 

285 
Kelantan,  acreage,  34  ;    growth  in,  85  ; 

annual  yields,  285 
Kepitigalla,  yield,  289-291 
Kew,  distribution  of  plants  from,  26-28 
Kinta  Kellas,  yield,  276 
Kintyre,  yield,  295 
Klanang,  yield,  275-280 
Klang,  rate  of  growth,  83-84  ;  soils,  159 
Knives,  tapping,    179-193  ;    requisites 

of  good,  181-182 
Kratok,   130-131 
Krebs's  smoking  method,  397 
Krian,  Rubber  Estates  of,  yield,  278 
Kuraa,  yield,  277 


INDEX. 


537 


Labour,  costs  and  kinds  of,  30 
Labu,  yield,  278,  280 
Lace   rubber,  405 
Lalang,  100,  103,  112,  127,  129-134 
Laintoro,  148 

Lanadron,  yield,  275,  278,  279,  281 
Landolphia,  6,  7,  27,  28,  46,  48,  49,  50, 
58  ;     latex,  325-326  ;     rubber,  430, 

433 

Latex,  properties  of.  315-320  ;  con- 
stituents, 59,  61,  315-319;  com- 
position, 316  ;  variation  in,  316- 
317;  caoutchouc  in,  316-317; 
resins,  316-318,  322  ;  proteins,  316- 
319,  322,  325  ;  ash,  316-317,  319  ; 
sugars,  316-318  ;  gums,  317-318  ; 
oil,  317  ;  enzymes,  318-319  ;  im- 
purities, 316-317 ;  reaction,  315, 
321,  330;  specific  gravity,  315; 
colour,  237-238  ;  functions,  58-64  ; 
effect  of  agents  on,  319-320  ;  dilution 
and  its  effects,  320,  322,  325-326  ; 
from  first  incisions,  315  ;  abnormal, 
258-259,  316  ;  non-coagulable,  223  ; 
quality  in  leaves  and  twigs,  218  ; 
effect  of  tapping  on,  257-258  ;  pro- 
tector, 214  ;  collecting,  214,  261  ;  on 
Amazon,  267  ;  keeping  it  liquid, 
321-322  ;  transport,  324  ;  cen- 
tralizing, 214  ;  straining,  322-323  ; 
production  of  rubber  from,  321-343  ; 
direct  use  of ,  4  60-462  ;  sulphurizing, 
461  ;     colouring,  461 

^aticiferous  vessels,  anatomy,  53-54  ; 
of  Hevea,  55-56,  58 ;  formation, 
56-57  ;     variability,  58 

Lavant,   yield,   294 

Leaf-fall  {see  Foliar  periodicity) 

Leaves,  food  in,  167  ;  quality  of  latex 
in,  218 

Lecanium,  493 

Ledbury,  yield,  280 

Lemon-grass,  loi  ;   cultivation,  140 

Lepidiota  (cockchafer),  492,  504-505 

Leptocorisa,  493 

Leuconotis,  6,  47,  48,  49 

Liberia,  acreage,  40  ;  climate,  73-74  ; 
rate  of  growth,  90 

Light,  action  on  rubber,  443 

Lime-sulphur  wash,  489,  495,  501 

Liming,  11 1 

Linggi,  yield,  273,  281-282,  284 

Lobeiiaceae,  47 

Lochnagar,   yield,   290 

Locusts,   494 

Loss  of  weight  in  transit,  412,  415 

Lumut,  yield,  276 

Macadam's  comb  pricker,  189 
Macadam-Miller  paring  knife,    rSg-igo 
Maceration  of  bark  shavings,  356,  360  ; 

machines,  357-359 
Machines,  crgping,  356-359  ;    sheeting, 

356.  358,  359  ;    macerating,  357-359 
Mackenzie's  knife,  183 


Mahawale,  yield,  288,  289 

Main's  centrifugal  machine,  339 

Maize,  139  ;   cultivation,  144 

Malacca,  acreage,  34  ;  climate,  70  ; 
rate  of  growth,  84  ;  annual  yields 
285 

Malacca  R.  Plantations,  yield,  278-280 

Malaya,  Hevea  introduced,  26  ;  acre- 
age, 32-35,  45  ;  climate,  68-70  ; 
soils,  100,  159  ;  water-level,  307  ; 
rate  of  growth,  82-85  ;  methods  of 
cultivation,  100  ;  catch  and  inter- 
crops, 100,  128,  138-139  ;  tapping 
practices,  243-245  ;  exports,  14  ; 
distribution  of,  14  ;  estimated 
future  output,  14-15  ;  early  yields, 
272  ;  jdelds  from  young  trees,  273  ; 
from  old  trees,  273-274  ;  from  trees 
of  definite  ages,  274-283  ;  per  acre 
and  per  tree,  285  ;  annual  yields, 
285-286  ;  successive  annual  yields 
from  specified  trees,  283-284 ; 
analysis  of  rubber  from,  428-429  ; 
costs  of  planting,  521-522 

Manihot  {see  Ceara) 

Manila  hemp,  144 

Manufacture  of  rubber  goods,  458-460 

Manufacturers  on  plantation  rubber, 
416,  419-422 

Manures,  artificial,  168-169,  172  ;  mix- 
tures, 172-173  ;  ■  application  of,  167- 
168,  173  ;  green,  168-169,  173  ;  for 
nursery,  log  ;  for  young  plants,  168  ; 
experiments,  169-172  ;  for  increasing 
yield,  165-166 

Marabau,  137 

Mariaella,  501 

Marking  trees,  Northway  &  Bowman's 
system,  213  ;  HoUoway's,  213-214 

Mascarenhasia,  27,  46 

Mastication,     458 ;  behaviour     of 

plantation  rubber  during,  424 

Mathieu's  coagulator,  337 

Mauritius,  42 

Meal  from  seeds,  474-475 

Mechanical  coagulation,  335-339,  344 

Mechanical  tests,  45T-456 

Mechanical  qualities  of  plantation 
rubber,  415-419,  421 

Melodinus,  46 

Merryweather's  sprayers,  487-488 

Merton,  yield,  276 

Mexico,  44,  45 

Michie-Golledge  chisel,  246  ;  centri- 
fugal machine,  336-337  ;  process  of 
rapid  drying,  389 

Micrandra,  2,  46,  48 

Micrechites,  47 

Mikania,  130 

Miller's  knife,  190 

Mimosa,  130,  131,  174,  177 

Mineral  matter  {see  Ash) 

Minimum  girth  for  tapping  {see  Girth) 

Minimum  percentage  of  trees  for 
tapping,  228 


538 


INDEX. 


Mites,  492 

Mixing  in  manufacture,  458 
Mixing  of  lots  on  small  estates,  423 
Mixtures  as  coagulants.  328,  347,  348, 

350 

Moechotypa,  493 

Moisture  in  fine  hard,  370  ;  in  planta- 
tion rubber,  amount,  225,  226,  428- 
430  ;  effect  on  strength,  371-372  ; 
and  price,  372  ;  retention  of,  372- 
374 ;  manufacturers'  opinions  on 
latter,  373-374 

Monorail,  324 

Monthly  tapping,  235 

Mooply  Valley,  yield,  295 

Morning  tapping,  233-234 

Moulds  on  rubber,  343,  375 

Multiple  V's,  196-198,  243,  244,  246, 
249  ;   yields,  197-198 

Mytilaspis,  495 

Naphthalin,  501 

Narthupana,  yield,  289,  290 

Natural  coagulation,  326,  333 

Negri     Sembilan,     acreage,     32,     33  ; 

annual  yields,  285,  286 
Nerve,  351,  416-420,  444-445 
New  Guinea,  acreage,  37 ;  chmate,  72  ; 

rate  of  growth ,  88;  soils,  164  ;  yields, 

-301 
Nigeria,  acreage,  40 ;  climate,  74 ;  yields, 

300  :  analysis  of  rubber  from,  429 
Nitric  acid,  347,  348 
Non-coagulable  latex,  223 
North  Hummock,  yield,  278 
Northway    knife,    246  ;        system    of 

pricking,  252-253 
Norzagaray's  knife,   191 
Number  of  trees  per  acre  (table),  116 
Nursery  beds  and  plants,  109 
Nutmeg,  102,  139 

Nuts,  composition  of  smoke  from,  393 
Nyasaland,     acreage,      42  ;       rate     of 

growth,   91 

Oil,  in  latex,  317  ;  in  seeds,  474-475 
Oils,  action  on  rubber,  442 
Opposite  quarter  sections,  212-213 
Oxalic  acid,  348 
Oxidation  of  rubber,  318-319,  442 

P.P.K.,  yield,  294 

Pahang,  acreage,  32-33  ;  annual  yields, 

285 
Packing  of  rubber,   411-414;      cases, 

etc.,    411  ;       ventilation,    411-412  ; 

sorting  during,  412-413  ;    small  lots, 

413  ;   tacky  rubber,  413 
Packing  of  seeds,  476-478 
Palaqium,  49 
Panawal,  yield,  295 
Panawatte,  yield,  294 
Pandan,  yield,  275 
Pantiya,  yield,  295 
Papua  {see  New  Guinea) 


' '  Para ' '  knife  and  chisel,  186 

Parameria,  6,  46,  48,  49 

Paring,    parallel   and   irregular,    206 ; 

number  per  inch,  207-209,  243-249  ; 

versus  pricking,  1 83 ;  upper  edge,  198, 
.  205-206 ;  thickness  of,  207-208 
Paris  Green,  490 

Parit  Buntar  trees,  yield,  273,  282 
Parthenium  {see  Guayule) 
Pask-HoUoway  knife,  190 
Passara  group,  yield,  290,  292-293 
Passburg's  vacuum  drier,  386 
Passion  flower  (Passiflora),   100,    129- 

131,  177 

Pataling,  yield,  277,  281 

PelmaduUa,  yield,  289,  295 

Peltophorum,  104 

Penang,  acreage,  34  ;    yields,  274 

Penrith,  yield,  289 

Pepper,  139 

Perak,  acreage,  32-33  ;  rate  of  growth, 
84  ;  annual  yields,  285-286 

Perak  R.P.,  yield,  279 

Periyar,  yield,  295 

Periodicity,  leaf  and  fruit,  52,  53,  311- 
313;  and  tapping  arrangements,  229- 
233  ;  in  crops,  311-314  ;  effect  of 
tapping  on,  254 

Peru,  263,  269-270 

Permanent  set,  452 

Pestalozzia  (see  Thread  blight) 

Pests  {see  Diseases  and  pests) 

Petroleum  emulsion,  490,  493 

Phaseolus  (Kratok),  130-131 

Philippines,  acreage,  39  ;  climate,  73 

Physical  (and  mechanical)  properties 
of  rubber,  448-455  ;  of  plantation 
rubber,  415-419,  421  ;  relationship 
with  chemical  properties,  431-432 

Phytophthora  (see  Canker) 

Picric  acid  as  coagulant,  327 

Pineapples,  304  ;    cultivation,  144 

Pink  disease,  483,  495-497 

Plant  juices,  coagulauon  by,   326 

Plaiitation  rubber,  in  i(f-.  .\i9-420 ; 
composition,  415,  428-430  ;  age  of 
tree  and  quality,  419  ;  purity.  415- 
416  ;    dryness,  415-416  ;    direct  use, 

423  ;  keeping  qualities,  421  :  lack 
of  uniformity,  421-423  ;  manu- 
facturers' opinions,  416,  419-422  ; 
condition  on  marketting,  354  ;  cotn- 
pared  with  fine  hard,  415-419,  421, 
422  ;    behaviour  during  mastication, 

424  ;  during  vulcanization,  421-422  ; 
mechanical  and  physical  qualities. 
415-419,  421  ;  methods  of  testing, 
448-451  ;  results  of  tests,  415-419  : 
for  solutions,  424  ;  elastic  thread, 
425;  wire  covering,  425-426;  cut 
sheet,  426  ;  tyres,  426-427  ;  buffers, 
420  ;   boots  and  shoes,  420 

Plantations,  history,  13,  25  ;  future 
supplies  from,  14-18  ;  capitaliza- 
tion, 21-24 


INDEX. 


539- 


Planting,  108-111 

Planting    distance    {see    Distance    in 

planting) 
Platypus,  501 
Plumeria,  49 
Pollination,  artificial,  106 
Polymerisation,  346 
Pontianak,  49  (see  Jelutong  and  Dyera) 
Porcupines,  501-502 
Potassium  in  wasted  rubber,  441 
Power  for  driving  machines,  366-367 
Prices,  fine  hard,   18-20  ;     plantation, 

19-21 
Pricking,   182-183,  200-201,   204,   252- 

254 
Producing     capacity     of     plantations 

(tables),  314 
Production  of  rubber  from  latex,  321- 

343 
Proportion  of  scrap  in  crop,  239 
Proprietary  coagulants,  329 
Protective  colloids,  346,  439-440 
Protective  forest  belts,   100,  483-484  ; 

disadvantages,    483  ;       in    Malaya, 

483-484 
Protector  for  latex,  214 
Proteins,  in  latex,  316-319  ;     removal 

from,  341-342  ;    in  rubber,  225-226, 

258,    339-340.    341-343.    428-430 ; 

removal  from,  437-441  ;  distribu- 
tion in,  438-440  ;  in  coagulation, 
318-319,  322,  325,  344-345  ;  and 
tackiness,  446 

Pruning,  thumb-nail,  123-127,  229  ; 
of  roots,  134  ;   precautions,  487 

Pterolophia,  493 

Pterospermum,  104 

"Pull and  Push"  knife,  182,  243-244 

Pumps  for  water  supply,  368 

Pupala  shrub,  130 

Purification  of  rubber  (see  Washing) 

Purub,  329 

Province  Wellesley,  acreage,  34  ;  rate 
of  growth,  85  ;    annual  yields,  285 

Quality  of  rubber  and  age  of  trees,  222- 
419  ;   and  height  of  tapping,  222 

Queensland,  acreage,  37  ;  rate  of 
growth,  88  ;    yield,  301 

Railways,  light,  324 

Rainfall  (see  Climate,  under  heading  of 

particular  country) 
Rainfall  and  tapping,   230-233,   265  ; 

and  yields.  240,  311-314 
Rani  Travancore,  yield,  295 
Rate  of  growth  (see  Growth) 
Rats,  501-502 
Rayigam,  yield,  289 
Reaction  of  latex,  321,  315,  330 
Reaper  tapping  knife,  193 
Reclaimed   rubber,   469-470 
Record  yields,  282,  288 
Reformed  rubber,  470 
Rembia,  yield,  277 


Renewal  of  flow,  238 

Renewed  and  renewal  of  bark  (see  Bark 
renewed) 

Resiliency,  350 

Resins,  and  age  of  trees,  225-227,  432- 
433  ;  and  parts  of  trees,  222,  433  ; 
in  latex,  316-318,  322  ;  formation  in 
rubber,  442  ;  quantity  in  various 
rubbers,  433-434  :  in  fine  hard,  353  ; 
in  plantation  rubber,  225-226,  258, 
419,  428,  430  ;  quantity  desirable, 
434,  436  ;  effect  on  vulcanization, 
434-435  ;  removal  from  rubber, 
434-436  ;  value  of,  435-436  ;  ex- 
tracting machine,  436-437 

Resting  periods,  240  ;   on  Amazon,  266 

Rhyncodia,  6,  49  ;  analysis  of  rubber, 
430 

Robinson's  vacuum  drier,  387 

Rollers  of  machines,  sizes,  358  ;  groov- 
ing. 356-357  ;  chilling,  358  ;  speed, 
356-359 

Root  system,  rate  of  growth,  98-99  ; 
pruning,  134  ;  diseases,  iii,  131,  133, 
502-504 

Rose  beetle,  495 

Rosehaugh,  yield,  294 

Rosellinia,  504 

Rubana.  yield,  277 

Rubber,  origin  of  names  of,  i  ;  structure 
of  crude,  348-350 

Russia,  proposed  planting  m,  44 

Ryan's  callipers,  95 

Salts  as  coagulants,  347,  348,  350 

Samoa,  acreage,  38 ;  climate,  73  ; 
tapping  practices,  249 

Sanitation  of  plants,  general  principles, 
486 

Sanseveiria,  144 

Sapium,  i,  2,  6,  43,  46,  48 

Scale  bugs,  495 

Schopper's  testing  machine,  454-455 

Schwartz's  hysteresis  machine,  453-454 

Scolytidae,  501 

Scorpion  knife,  191 

Scrap,  percentage  in  crop,  239,  310- 
311;  washing,  356,  360,  361,  406; 
description,  etc.,  405,  406 

Sculfer  knife,  190,  246-248 

Seafield.  yield,  275-279 

Season,  best,  to  tap.  229-233 

Secure  knife,  190-191 

Seeds,  description,  50 ;  selection  of, 
106-107  ;  position  in  nursery.  109  ; 
at  stake,  108,  m  ;  pests.  491  ; 
number  from  trees,  471  ;  estimated 
crops,  471  ;  ,  weight  of,  471-473  ; 
effect  of  tapping,  255,  472  ;  packing 
of,  476-478  ;  superiority  of  autumn 
crop,  478-479  ;  oil  in,  474-475  ;  meal 
and  cake,  474-475  ;  ash  in  ditto, 
475-476  ;  value  for  export,  472-473  ; 
form  for  export,  473  ;  profit  from, 
473-474 


540 


INDEX. 


Selangor,  acreage,  32-33  ;  climate,  69  ; 
rate  of  growth,  83  ;  soils,  160  ;  annual 
yields,  275,  277-278,  280-282,  285-286 

Selangor  R.  Co.,  510 

Selection,  by  seed,  105-106  ;  chemical 
method,  107  ;  during  transplanting, 
108 ;  by  cuttings,  105,  107  ;  by 
marcotting,  107 

Selinising,  yield,  281 

Sempah,  yield,  276,  277 

Sendayan,  yield,  276 

Sengat,  yield,  276 

Serbadjadi,  yield,  297 

Serdang  Central,  yield,  297 

Seremban,  yield,  276,  277,  280-282 

Seychelles,  acreage,  39  ;   climate,  72 

Shade,  135-136,  146,  148  ;  nursery, 
109  ;    shade    trees,     103-104 

Shafting  for  factories,  363,  377 

Shaw's  smoker  coagulator,  397  ; 
vacuum  drier,  387  ;  blocking  press, 
408 

Sheets,  354,  374,  404,  418,  428-429 ; 
preparation,  334-335  ;  smoked,  392, 
419  ;   machines,  356,  358-359 

Shelf ord,  276-279 

Sialang,  yield,  297 

Siam,  acreage,  35 

Sieves  for  straining,  322-323 

Silt-traps,  114 

Singapore,  acreage,  34  ;  climate,  70  ; 
rate  of  growth,  82-83,  92-93  ;  yields, 
274  ;    arrival  of  first  plants,  27 

Singapore  Para,  yield,  282 

Single  oblique  cuts,  195,  196,  243-247 

Sione,  yield,  280-281 

Siphocampylus,  47 

' '  Sirocco ' '  drying  plant,  385 

Six-day  tapping,  239-240 

Size  of  tree,  and  tapping  {see  Girth) 

Slugs,  501 

Small  lots  of  rubber,  413 

Smith's  centrifugal  machine,  338-339 

Smoke,  coagulation  by,  on  Amazon, 
267,  327,  393  ;  at  Singapore,  394  ; 
Da  Costa  method,  395-396-;  Shaw's, 
397  ;  Dickson's,  396  ;  Wickham's, 
394-395;  "  Fumero, "  397  ;  Derry's, 
394  ;  Bertram's,  394  ;  Sutton's, 
394  :    Krebs's,  397 

Smoked  sheet,  392,  419;  biscuit,  419, 
428 

Smoking  of  rubber,  external,  381,  383- 
385,  397-402,  424,  426  ;  in  main 
building,  381,  383.  400  ;  in  separate 
houses,     390-401  ;      fires,     383-385, 

398-399 ;  fuel,  384,  393,  397-399 ; 

advantages  of,  391 ;  quality  of  rubber 
39T,  424-426  ;  demand  for,  392 
Soil  fungicides,  489  ;  insecticides,  490 
Soils,  149-178 ;  in  Brazil,  29,  149  ; 
swampy,  treatment,  153-155  ;  im- 
provement under  forest  vegetation, 
167  ;  poor,  good  growth  on,  152  {see 
soils,   under  various  countries) 


Solomon  Islands,  38 

Solution,  plantation  rubber  for,   403, 

420,  438-440,  442 
Sonchus,  47,  49 
Sorting  of  rubber,  during  packing,  412- 

413  ;  at  wharves,  414 
South  India  {see  India,  South) 
South  of  Ceylon,  yield,  291 
Southern  Ceylon,  yield,  290 
Sow-thistle,  47 
Soya  bean,  130 
Specific    gravity,    of    latex,    315  ;     of 

rubber,  351,  444 
Specific  heat  of  rubber,  443 
Sphaerostilbe,  504 
Spindle  rubber,  394,  418 
Spiral    tapping,     full,     199-203,     245 ; 

half, 201,  202,  243-247 
Spray  coagulator,  335 
Spraying,  apparatus.  132,  486-488  ;    of 

lalang,    132  -133 
Srinivasagam's  knife,  192 
Standardization  of  accounts,  509 
Starch  in  latex,  318 
Steam  ploughs,  131 
Stem,  growth  of,  78,  92-93  ;   structure, 

54-55 

Stone  cells,  253-254 

Storing,  effects  of,  424  ;  at  wharves, 
414 

Straining  of  latex,  322-323 

Straits  Bertam,  yield,  275,  278 

Straits  Settlements,  acreage,  32-34 

Straits  R.  Co.,  yield,  275,  276 

Strawsonite,  488 

Structure  of  rubber,  348-351 

Stumps  and  logs,  removal,  112,  486- 
487,  500 

Stumps  (nursery),  108-11T  ;  forward- 
ing of,  479-481 

Sub-permanent  set,  452 

Substitutes,  467-468 

Suduganga,  yield,  289-291 

Sugarcane,  100-102,  128,  131,  138-139, 
304-305  ;    cultivation.  145 

Sugars  in  latex,  316-318 

Sulphur,  action  on  rubber;  442  ;  in 
vulcanization,  459-461  ;  as  in- 
secticide, 490 

Sulphurizing  freshly  coagulated  rubber, 
462 

Sulphuric  acid  in  coagulation,  128, 
347-348 

Sumatra,  acreage,  35-36  ;  climate,  70  : 
soils,  102,  163,  water  level,  307  ; 
rate  of  growth,  86-87  '■  catch  and 
intercrops,  102-103,  139  ;  tapping 
practices,  248-249  ;  yields  in,  297-298 

Sumatra  Para,  yield,  297 

Sungei  Kapar,  yield,  279 

Sungei  Kari,  yield,  297 

Sungei  Krian,  yield,  275-276 

Sunlight  and  tackiness,  446 

Superposition  of  incisions  and  yield, 
309 


INDEX. 


541 


Supervision  of  tapping,  206 

Surgical  scrapers,  184 

Surinam,    acreage,    44  ;     climate,    77  ; 

soils,    165  ;     rate    of    growth,    01  ; 

yields,  301 
Sutton's      smoker      coagulator,       394 

creosote  generator,  398 
Swampy   soils,    114,    151  ;     treatment, 

153-155 
Synthetic  rubber,  465-467 
Systems  in  tapping,  211-213,  243-249 

Tabernaemontana,   46 

Tacky  rubber,  analysis,  446 ;  from 
first  tappings,   222-223 

Tackiness,  375,  445-448 ;  changes 
during,  448 ;  bacteria  and,  318, 
445-446  ;  proteins  and,  318,  446  ; 
sunlight  and,  446  ;  heat  and,  447  ; 
chemical  causes,  447 ;  imperfect 
coagulation,  447-448 ;    enzymes  and, 

319 

Taiping,  yield,  276 

Taldua,  yield,  290 

Tannic  acid  as  coagulant,  328 

Tapanoeli,  yield,  297 

Tapioca,  100-102,  128,  131,  138,  139, 
304,  497  ;     cultivation,  142-143 

Tapping,  general  principles,  194,  203- 
205,  systems,  194-217 ;  3-year 
system,  211  ;  4-year  system,  211-213; 
author's  proposals,  212  ;  Gallagher's, 
212  ;  Fitting's,  212  ;  two  managers' 
arguments,  210-211  ;  systems  pre- 
ferred in  East,  243-249  ;  methods 
in  Africa,  194-195  ;  on  Amazon,  194, 
260-271 ;  methods  in  East  (see  Spiral, 
Herringbone,  V,  Vertical,  Single 
Oblique  Cuts,  etc.)  ;  knives  {see 
Knives) ;  lines,  distance  between, 
208,  209,  211,  243-249  ;  slope  of,  211  ; 
cuts,  number  per  inch,  207-208, 
243-249  ;  and  minimum  girth  of  tree, 
224,  227-228 ;  compass  tapping, 
234 ;  areas,  best,  218-223  ;  height 
of  and  quality,  222-223  ;  basal, 
219,  224,  228  ;  high,  218-223  ;  ex- 
periments at  different  heights,  219- 
223  ;  how  to  increase  area,  228-229  ; 
time  of  day,  233-234,  260,  308 ;  best 
season,  229-233  ;  and  periodicity 
(leaf-fall,  etc.),  229-233  ;  resting 
periods,  240  ;  and  rainfall,  230-233, 
308,  311-314  ;  supervision  of,  206, 
304 ;  number  of  trees  per  cooly, 
207,  210  ;  first,  and  tacky  rubber, 
222-223  ;  frequency,  211,  232,  234- 
241  ;  and  composition  of  latex,  236, 
239.  258  ;  and  quality  of  rubber, 
256-258 ;  and  reduction  in  yields, 
255-256  ;  and  bark  renewal,  241  ; 
daily,  234-240 ;  alternate  days, 
234-240  ;  three  day,  239-240,  246  ; 
twice  and  once  a  week  and  monthly, 
335  ;     frequencies  preferred  in  East, 


243-249  ;    on  Amazon,  266  ;     effects 
of,    250-259 ;      on     Amazon,    261  ; 
effects  of  prolonged,  232  ;     of  bad, 
179-180  ;     effect  on  growth,  255  ;   on 
renewal  of  bark,  229  ;  on  latex,  258  ; 
on  plant  reserves,   251  ;      on  perio- 
dicity, 254  ;   on  seeds,  255. 
Tarring,  180,  497,  498,  501 
Tartaric  acid  as  coagulant,  348 
Tea.  loi,  134,  138,  139,  303,   304-482, 
484,  491,  496,  497  ;    cultivation,  146 
Temperature  {see  Climate,  under  various 

countries) 
Tensile  strength,  350,  351,  451-456 
Tephrusia,  130,  174,  177 
Termes    gestroi,       498-500 ;       T.     ca- 
bonarius,  494  ;    T.   inanis,     501  ;    T. 
redemanni,  504 
Terracing,  loi,  114 
Testing     of     rubber,     431,     448-451  ; 

machines,  453-455 
Tests,  mechanical,  451-456  ;    adhesion, 
450  ;    viscosity,  450,  456  ;    physical, 
456  ;    chemical,     451,    456-457  ;     for 
acid,  450 
Thinning  out,  117,  121-122 
Thread  blight,  491,  495 
Thumbnail  pruning,  124-127,  229 
Thyridaria  {see  Botryodiplodia) 
Time  that  latex  flows,  308-309 
Time  of  day  for  tapping,  233-234 
Tisdall's  knife,  192 

Tobacco,  102,   103,   128,   131 ;    cultiva- 
tion,   139 
Togo,  rubber  in,  39  ;  climate,  75  ;  yields, 

300 
Transplanting,    109,    115  ;       selection 

during,    108 
Transport  of  latex  to  factory,  324 
Transport  of  seeds  oversea,    476-480  ; 

of  stumps,   480-481 
Travancore  R.  Co.,  yield,  295 
Trees    per    acre     (table);       116;      on 

Amazon,    264 
Tremelbye,   yield,   276 
Trichloracetic  acid  as  coagulant,    347, 

350 
Trinidad,    acreage    (and   Tobago),    43; 

climate,    75-76 ;      soils,    165  ;      rate 

of   growth,   91 
Twisting  of  stems,  491 
Tyres,  plantation  rubber  for,  420 

Uganda,   acreage,   41  ;      climate,    75  ; 

rate  of  growth,  90 
Uniformity,  lack  of,  421-423  ;    causes, 

423 
United  Serdang,  yield,  297 
United  Sumatra,  yield,  297 
' '  Universal ' '  machine,  361  -362 
Urceola,  38,  46,  48,  49  ;     analysis  of 

rubber,  430 
Urticaceae,  47 
Uses  of  rubber,  464-465  ;  of  plantation 

rubber,  227,  419-427 


i42 


INDEX. 


V  implement  for  tapping,  187 

V  (or  Y)  incisions,  basal,  195-196, 
243-248 ;  multiple,  196,  243-244, 
246,     249 ;        inverted,     197,     246 

Vacuum  drying,  385-389 ;  general 
remarks,  387-388  ;  air  bubbles  and, 
389  ;  Shaw's,  387  ;  Robinson's,  387  ; 
Bridge's,  387  ;    Passburg's,  386 

"Valient"  sprayer,  488 

Vallambrosa,  yield,  276-281,  284,  305 

' '  Valour ' '  machine,  360 

Van  der  Kerckhove's  knife,  191 

Vaporite,  492,  493,  501 

Variability  in  plantation  rubber,  421- 
423  ;  causes,  423 

Variations,  natural,  in  yields,  302-303 

Vertical  method  of  tapping,  201 

Vigna,  130,  174 

Viscosity,  350,  417-418,  450-456 

Vulcanite,  464 

Vulcanization,  351,  459-460 ;  be- 
haviour of  plantation  rubber  in, 
421-422 


Walker's  combination  knife,  191 

Wardian  cases,  479-480 

Warts  following  pricking,  253 

Washed  rubber,  characters,  354 

Washing  of  rubber,  purposes,  340-341, 
352-355  ;  effects  of  not  doing  so, 
355  ;  points  in,  354  ;  scrap,  356, 
360-361  ;  by  manufacturers,  352  ; 
less  in,  352-354  ;  machines,  355- 
362  ;  early,  355  ;  types,  355-357  : 
outturn,  366  ;  hand-power,  360 

Wasps,  492 

Water  in  rubber  {see  Moisture)  ; 
absorption  by,  443  ;  for  washing, 
heating  of,  369  ;  supply,  368  ; 
purification,  367-368 

Water  in  soils,  and  yields,  307 

Water  pits,  102 

Water  level  in  soil  {see  Ceylon,  Malaya, 
Sumatra) 

Weed  killers,  1 30-1 31 

Weeding,  127-131,  134  ;  costs,  127  ; 
turning  weeds  into  soil,  173 

Weekly  tapping,  235,  239-240 

Weevils,  495 

West  Indies,  acreage,  42,  43,  45  ; 
climate,  75-76  ;  soils,  164-165  ;  rate 
of  growth,  91  ;  analysis  of  rubber 
from,  429 

Wet  plantation  rubber  {see  Moisture) 

Wharves,  rubber  at,  413-414 


When  to  tap,  224-242 

Where  to  tap,  218-223 

White  ants,  rii,  131-133,  136-137, 
494,  498-504  ;  general  treatment, 
500  ;  fumigation,  500  ;  and  rubber 
exudations,  499  ;    and  root  disease, 

503 
Wickham,  brings  seeds  to  Kew,  25-26  ; 

on    parent    plants,    29  ;        smoking 

process,  29 
Willughbeia,  6,  46,  48,  49 
Wild  rubber,  5-6  :    equivalent  acreage, 

12-13 
Wind,  damage  by,  104 
Windbelts,  104,  308 
Woodend,  yield,  295 
World's  acreage,  45 
Worm  rubber,  405 
Wound  response,  236-240  ;  on  Amazon, 

266 
Wynn-Timmius  knife,  193 

Xylinabaria,  46 
Xyloborus,  501 
Xylopertha,  501 

Y  (or  V)  basal,  195-196,  243-248 

Yatiyantota,  yield,  294 

Yield,  general  considerations  affecting, 
302-314  ;  per  acre,  table  for  estimat- 
ing, 314  ;  high  per  acre,  306  ;  and 
water  in  soils,  307  ;  and  rainfall, 
311-314  ;  and  atmospheric  pressure, 
307-308  ;  and  elevation,  296,  303  ; 
natural  variations  in,  302-303  ; 
estate  conditions  affecting,  303  ; 
and  distance  in  planting,  305-306  ; 
effect  of  intercrops,  304-305  ;  and 
size  of  tree,  306-307  ;  and  rate  of 
growth,  303-304  ;  and  time  latex 
flows,  308-309  ;  and  superposition  of 
incisions,  309  ;  reduction  in,  and 
frequent  tapping,  255-256 

Yields  on  Amazon,  267-271 ;  Borneo, 
299  ;  Burmah,  301 ;  Cameroon,  300 ; 
Ceylon,  287-295 ;  Cochin  China.  301 ; 
Congo  Free  State,  300-301 ;  Gold 
Coast,  299-300;  Java,  299;  Malaya, 
272-283,  305-306;  New  Guinea,  301 ; 
Nigeria,  300  ;  Queensland,  301  ; 
South  India,  295-296;  Sumatra,  297- 
298;  Togo,  300 

Young  trees,  quahty  of  rubber  from, 
225-227 

Zig-zag  tapping,  199 


ADVERTISEMENTS 


SPECIAL  NOTICE  TO  THE  RUBBER  PIAIITIIIG  WORLD. 


1         PARA,    GASTILLOA,    CEARA,    FUNTUMIA   (TRUE),    MANIHOT    DICHOTOMA, 

PIAUHYENSIS,    HEPTAPHYLLA     NEW    VARIETIES    OF    MANICOBA), 
I  MIMUSOPS  GLOBOSA  (BALATA),  LANDOLPHIA  KIRKI,  Etc. 

■^  Seeds,    Plants,   and    Stumps   forwarded  to    all    parts    of    the    World. 


a  TEA.— -Manipuri  Indigenous  Daik  Leaf  approved  Jats.    1911   crop   sold  to  Mexico,   South   India, 

^  Java,  etc.    Orders  being  t>ooked  for  1912  crop  and  onwards. 

•3  TEA  SEEDS  FOE  MEXICO.— Landon,  2nd  September,  1910:— "On  receipt  of  this  letter  pleaae 

S  carefully  prepare  10  maunds  picked  Seed  Thea  Tiridis  at  £  — -  per  maimd,  10  maunds  Thea  Aseotaica 

at  £  —  per  inaund."  !*- 

"'  PABA  SEEDS  AND  STUMPS.— Orders  bein^  booked  for  1912  session  and  onwards,  seeds  already  e 

o  booked  over  five  million  for  August-September  shipment,  Btuanps  over  two  million  for  ^ipment  April  A 

|§  onwards  in  closed  cases  amd  in  Wardian  cases.  S> 

j|  WARDIAN  OASES  OF  PAEA  STUMPS.— On  shipping  75,000  in  August  the  following  wire  order  « 

13  has  been  received  on  the  7th  September:— "  Duplicate  last  order  Wardian  Stumps";    also  25,000  Paxa  g 

^  Seed  by  Parcel'  Foot  and  225,000  by  freight  has  been  forwarded  to  the  easoQ  addreaa.  h 

■g  FOE  DUTCH  GUIANA.— The  Diiectoa:  of  an  Agricultural  Department  writes  11th  August,  1910;—  w 

g  "The  Agricultuial  Department  has  ordered  in  total   560,000  Para  Seed."  5 

■^  *'  The  India  Bubber  Journal  "  Quotes  from  the  "  Tropenpfianzer,"  touching  one  of  our  Para  stump  • 

a  shipments :—"  The  writer  saw  100,000  of  these  stumps  wihich  hod  just  been   planted   out,   none   were  ^ 

S  dead,  and  many  were  putting  out  new  roots.    The  (^ylon  consignors,  J.  P.  William  and  Bros.,  Hena-  ^ 

a  latgoda,  guarantee  a  mortality  not  exceeding  25  per  cent.,  and  the  Manager  of   the  Upola  Company  & 

"-I  estimated  the  lose  on  this  batch  at  2  per  cent.  only.    This  is  decidedly  the  beeb  method  of  transporting  q 

_  Heveas."  q- 

g  SAMPLE  PARA  STUMPS  forwarded  by  sample  post   to  intending   purchasers  in   all   countries,  I" 

J5  Post   Free.  g 

*"  PAEA      STUMPS      m      CLOSED      CASES.  * 

"S  DEMEE ABA.— Secretary  of  an  Agricultural  Estates,  Ltd.,   of  British   Guiana  writes;  New  York  S 

«  U.S.A.,   11th  April,  1911:—"  The  enclosed  copy  of  our   letter  of  even  date  to  your  London  Agents  will  >tj 

S  abow  you  that  tiiey  have  advised  us  by  telegraph  of  the  stdpping  arrangeaaeaits  in  regard  to  the  order  ,  g 

3  for  seventy  thousand  (70,000)  stumps  placed  with  you  through  our   Londion   representatives.    We   shall  » 

^  most  likely  require  something  like  200,000  seeds,"    The  cost  of  Paxa  etumpa  in  closed  cases  is  about  g 

■B  half  when  compared  with  Wardian  cases.  & 

0  PHILIPPINE  ISLANDS.— Manager  of  an  extensive  rubber  plantations,  in  ordering  75,000  Para  O 
•o  stumps,  writes,  dating  Mindanao,  27th  November,  1910:— "Tour  first  conadgnment  of  Para  seeds  were  a  £ 
g  great  success."  ^- 

«-  GOVEENMENT    OEDEE.— On    reijeiving    25,000    Para  seed  by  Parcel  Post  at   Sierra  Leone  in  S 

^  October,  a  repeat  order  recerived  on  14th  November,  1911,  runs  as  folLowe :  — "  With  reference  to  your  m 

«  letter  of  10th  inst.,  please  send  at  once  50^000  Para  Eubber  seed  by  Parcel  Post  .to Sierra  Leone,  p 

»  West  Africa."  g; 

«■  GLASGOW.— Secretariee  of  a  Bubber  Estates  Co.,    Ltd.,  of    Mexico,  writes,   17th  March,  1911:—  § 

f"  We  have  pleasure  ini  informing  you  i^t  our  Directors  are  satisfied  with  the  result  obtained  from  the 

__  ten  thousand  Hevea  seeds  got  from  you  last  year,  and  they  desire   this  year  to   plaut   another  thirty  S- 

ft  thousand  seed."  ^ 

'-'  TBINIDAD— A  Planter  writes,  St  Joseph,  February  3rd,  1911:— "I  dudy  received  the  50,000  Hevea  * 

«■  Seed,    I  am  about  forming  a  Syndicate  of  the  planters  to  order  250,000  Hevea  Seed."  tn 

•  MANGO    GEAFTS^— Over  75  varieties,  including   Creeping,  twice-bearing,  all  -tihe  year  round  bear-  g 

•  ing.  LITCHI  GEAFTS.— 22  varieties,  including  seedless.  SAPODILLA  GEAFT  all  the  year  round.  • 
^  Skeds  Aia>  Plants  os  nttmebous  Commebcial  Pbodtigts  SuppLisn,  rNCLUDiNG  Tea,  Ceij:bbated  Caba-  ^ 
H  vohioa,  Mamaba    BAnro  asd  Spbnce  Cotton,  Abasian  Libebian  Hybeid  Coftbh,  Coffee  Bobuata,  Oofpeb  & 

^  OOKOBNBIS  TAB.    OhALOTI  PBOVBD  TO   BBS  ABSOLUTELY    EEBIBTINO    HeMCTLEIA    VEBTBATBIX,     SOYA    BBAN,    GBHBK  ^ 

^  Sauabow  extbbmblt  eably  and  peolipio,  GrANT  Tellow  Santa  Mabgaeita,  op  bnoemous  gbowth,  beans  S 

teby  laegb,  exteembly  PEOLtrio,  OocoA,  Kola,  Sibal,  and  otecbe  Fibbes,  etc.  g' 

5  For  Gieen  Manuring.- Ceotolabia  Steiata,  Viqna,  Albizzia  Molucoana,  Pasbiploba  PoBTrnA,  Cassu  '^ 

MzMosozDES  Tbpheobia  Candida,  1.  Pubpubia,  Beanb,  etc..   Seeds.  S 

*•  Six  Deecidptive  Catalogues,  with  Circulars  and  Special  offers  pas*  free  to  foreign  countries. 

^  Separate  Price  List  for    Ceylon. 

S  "  SOUTH  AFBICA,"  the  great  authority  on  South  African  affairs,  says:—"  An  interesting  Catalogue 

1  reaches  us  from  the  East.  It  is  issued  by  WILLIAM  BE0THEE8,  Tropical  Seed  Merchants,  of  Hena- 
a  ratgoda,  O^lon,  and  schedules  all  the  useful  and  beautiful  plants  which  will  thrive  in  tropical  and 
g  S6mi4ropical  i^ons.  We  fancy  Messrs.  Williams  should  do  good  business,  for  now  that  tihe  great 
3  Powers  have  grabbed  all  the  waste  places  of  tihe  earth,  they  nmst  turn  to  and  prove  i^t  they  were 
*^  worth  the  grabbing.  We  recommend  the  great  Powcts  and  Concessionaries  under  ttiem  to  go  to  William 
J-  Bros. 

£i  Agents   in   London :— Messrs.    P.    W-   Woollby  and   Co.,   90,  Lower  Thams   Street. 

•  Agents  in  Colombo,   Ceylon : —Messrs.   E.   B.   Obbasy  and  Oa 

sl  No  Sole  Agents  Anywhere. 

^  J.     P.     WILLIAM     &     BROTHERS, 

%  Tel^raphio  Address:—                                                        Tropical    Seeds    and    Plants    MerahAnts, 

%  WnxiAU,  Hbnabatgoda,  Ceylon.                                                                             Hbnakatooda,   Citlon 

^  lAha^B,  A.I.  and  A.B.O.  Oodra  [4th  and  5lh  Editions)  used. 

^  Also  Prints  Ood«& 


ADVERTISEMENTS 


Sole  Patentees  and  Manufacturers  : 

Francis  Shaw  8  Co,,  Ltd,, 

GORBETT  STREET  IRONWORKS^ 

Bradford,    Manchester,    Eng., 

— :  AND  : — 

139y  Gannon  Street,   London^  E.G. 


LARGEST  MAKERS  IN  THE  WORLD  OF 

Rubber  Plantation  Machinery 

Cables :  Telephones : 

Calender,  Manchester.  1749,  Central,  Manchester. 

Vibrate,  London.  5788,  London  Wall. 

Codes:   Ai.     A.B.C,  5th  Edition. 


Sole  Agents  in   F.MS,  and  Sumatra: — 
GUTHRIE    &    Co.,    Ltd., 

Singapore,   Penang,   Kwala  Lumpur,  &c. 

Sole  Agents  in  Ceylon  and  Southern  India  : — 
WALKER,    SONS    &    Co..    Ltd., 

Colombo  and   Kandy- 
Sole  Agents  in  Java  : — 

MACHINEFABRIEK,  "  AMSTERDAM," 

Soerabaia,  Java. 


INDEX     TO     ADVERTISEMENTS. 


Name. 
Abraham,  J.  P 
Acme  Chemical  Co.,  Ltd. 
Acme  Tea  Chest  Co.,  Ltd. 
Anglo  Continental  Guano  Works,  Ltd. 
Anglo  Dutch  Estates  Agency,  Ltd. 
Assoc,  des  Planteurs  de  Caoutchouc. 

Baur,  A. 

BayUss,  Jones  and  Bayliss,  Ltd. 

Berry,  Hy.  and  Co.,  Ltd. 

Bertrams,  Ltd. 

Blackman  Export  Co.,  Ltd. 

Bohringer,  Ch.  and  A. 

Bridge,  David  and  Co.,  Ltd. 

Brindley.  H. 
Bull  Wharf,  Ltd 
Bussey  J.  H  de. 

Chemical  Union,  Ltd. 

Chemical    Works,    late    H.    and    E. 

Albert. 
Clarke,  T.  A.  W.,  Ltd. 
Cochrane,  W.  H.  and  Co. 

Colombo  Commercial  Co. 

Cope,  Stuart  R. 
Cowieson,  F.  D.  and  Co. 
Cussons,  G.,  Ltd. 
Darlington  Wire  Fencing  Co. 
Davidson  and  Co.,  Ltd. 
Dee,  Joseph  and  Sons,  Ltd. 

Federated  Engineering  Co.,  Ltd. 
Ferguson,  A.  M.  and  J. 
Financier. 
Financial  News. 
Financial  Times. 
Freudenburg'  and  Co. 

Glasgow  Steel  Roofing  Co.,  Ltd. 
Gordon,  John  and  Co. 
Gummi  Zeitung. 
Guthrie  and  Co.,  Ltd. 

Hutchinson,  Jeffares  and  Co. 

India-Rubber  Journal. 
India-Rubber  World. 
International  Rubber  Exhibition. 

Johnson,  S.  H  and  Co.,  Ltd. 

Kalisjmdikat,  G.  m.  b.  H. 
Kolonial  Wirtschaftliches  Komitee. 
Krupp,  Fried.  A.  G. 


A  rticle  and  Page . 
Seeds,  no 
Insecticides,   io5 
Rubber  Chests,  102 
Fertilisers,  no 
Estate  Supphes,  loi 
Trade  Publication,  100 

Fertilisers,  89 

Fencing  and  Corrugated  Iron,  106 

Plantation  Machinery,  77 

Plantation  Machinery,    70 

Drying  Apparatus,  94 

Lactic  Acid,  107 

Plantation  Machinery,  28,  29,  30, 

32,  33.  34.  35 
Tapping  Knives,  in 
Wharfingers,   50,   51 
Technical  Book,  119 

Fertilisers,  105 
Fertilisers,  113 


31. 


Plantation  Machinery,  73 

Plantation  Machinery  and    Buildings, 

38,  39,  40,  41,  42 
Plantation   Machinery   and   Buildings 

66,  67 
Seeds,  43 
Buildings,  in 
Testing  Apparatus,  80 

Fencing,  76 

Plantation  Machinery,  109 

Jodelite  Termite  Preventative,  82 

Plantation  Machinery,  92 

Technical  Books,  86,  87 

Financial  Newspaper,  98 

88 

93 
Fertilisers,  68,  69 

Buildings,  103 

Plantation  Machinery,  56,  57 
Trade  Publication,  122 
Estates  Agents.  95 

Tree  Gutters,  90 

Trade  Journal,  121 
Trade  Journal,  n8 
Exhibitions,  96 

Filter  Presses,  74 

Fertilisers,  108 
Technical  Books,  117 
Plantation  Machinery,  75 


A  D  VERTISEMENTS 


1 


RUBBeRs 


sHMV's 


IT^CHINERX 


IMPORTANT  NOnCE. 

'"THE  SHAW  MACHINES  have  been  more  extensively 
adopted  on  Rubber  Estates  than  any  other  make  owning 
to  their  reputation  for  RELIABILITY,  EFFICIENCY,  AND 
EASY  RUNNING.  We  give  below  a  necessarily  incomplete 
list  of  Estates  using  Shaw  Machines  and  we  request  intending 
purchasers  before  decidmg  to 

ASK  THE  MAN  WHO  USES  THEM. 


::o:: 

SOME    ESTATES    USING    SHAW    MACHINES. 


H.H.  Sultan  of  Johore 

Estates  . 
LiNGGi  Estates. 
Malacca    ,, 
F.M.S.  Rubber  Go's 

Estates. 
Sekong 
Sandycroft 
Sungei  Buaya 
Mount  Austin 
Paradise 
BUKIT   Cloh 
Tanjong  Malim     ,, 
United  Malaysian 

Estates. 
BoEY  Seng's 
Kapar  Para 
TowKAY  Yeoh  Paik 

Estates 
Keats 

durian  tunggul    , 
Bukit  Panjang        , 
BuKiT  Kajang 
Sendayan  ,, 

Banteng 

PUCHONG 
TjIKADOE 

Pasir  Waringin 
Rim  Malacca 


Golconda  Malay 

Estate 
Cicely 
Labu 

Kuala  Lumpur 
United  Temiang 
Kamuning 
Adda  and  Pandan 

Estates. 
Lankat  River 
Glen  Bervie 
West  Country 
Galang  Besar 
Sungei  Kapar 
Bukit  Nanas 
Pengeram 
Port  Dickson 
Towkay  Loke  Yews 

Estates. 
Jalan  Acob 
North  Hummock     ,, 
Scottish  Malay  Go's 

Estates. 
Sagga 
New  Labu 
The  Atlas 
Towkay  Tan  Chay 

Yans  Estates. 

Haydep 


Sedenak      Estates. 

KoMBOjc    Estate. 

BiDOR  Estates. 

Alloowhari  Estates 

Deviturai 

St.  George's 

Waga 

Langslaxd 

Tallagalla 

Vincit 

Halpe 

Pallegodde 

Panawalle 

Kepitigalla 

Venture 

Weoya 

Magmally 

Galphele 

Kirby 

Caledonia 

Vincit 

Delwita 

Las  Cascadas 

soconusco 

DUNKWA 

Sempah 
Sennah 

Anglo  Johore   ,, 
Padang  Kajah  ,, 


-::o::- 


FRANCIS    SHAW    &    CO.,    LTD., 
BRADFORD,    MANCHESTER. 


INDEX     TO     ADVERTISERS 


Name. 

Latex  Engineering  Co. 

Le  Caoutchouc  and  La  Gutta  percha. 

Maclaren  and  Sons,  Ltd. 
Merryweather  and  Sons. 
Monorail  Portable  Railway  Co. 

Nieuw  Praauwenveer. 
Newey,  Thos.  and  Sons. 
Osterreith  and  Co. 

Passburg,  Emil. 
Perkin  and  Co.,  Ltd. 
Port  of  London  Authority. 
Pulsometer  Engineering  Co.,  Ltd. 

Richard,  J.  P. 

Riley,  Hargreaves  and  Co.,  Ltd. 
Robertson,  A.  R.  and  Co. 
Robinson,  Jos.  and  Co. 

Rubber  Estate  Agency,  Ltd. 

Schlieper,  Carl 

Shaw,  Francis  and  Co.,  Ltd. 

Societe  Coloniale  Anversoise. 
Schopper,  Louis. 
Skelton   and   Schofield. 
Strawsons  and  Co. 
Stroohoedenveem. 

Technical  Bureau  ' '  Soenda. ' ' 
Tyneside  Foundry  and  Engineering 

Co. 
Van  Starrex,  A. 

Venesta,  Ltd. 

Walker,  Sons  and  Co.,  Ltd. 

Weber,  Smith  and  Hoare. 
Werner  Pfleiderer  and  Perkins,  Ltd. 
Williams,  J.  P.  and  Bros. 
William  and  Richard. 
Wotherspoon,  J.  M.  and  Co.,  Ltd. 

Wynn  Timmins  and  Co. 
Yates  and  Co.,  Ltd. 


Address  and  Page. 

Plantation  Machinery,  85 
Trade  Publication,  116 

Technical  Books,   104 
Sprayers-  etc.,  60,  61 
Portable  Railwa5's,  64,  65 

Forwarding  Agents,  112 
Tapping    Knives,    114 

Merchants,  120 

Vacuum  Dryers,  72 
Portable  Engines,  84 
Wharfingers,    52 
Pumps,  etc.,  81 

Seeds,  91 

Plantation  Machinery,  79 

Belting,  109 

Plantation  Machinery,  18,   19,  20,   21, 

22,  23,  24,  25 
Estate  Agents,  99 

Plantation  Tools  and  Machinery,  71 
Plantation  Machinery,  2,  4,  6,  7,  8,  9, 

10,  II,  12,  13,  14,  15 
Rubber  Importers,  Merchants,  etc.,  104 
Testing  Apparatus,  113 
Tapping  Knives,  105 
Insecticides,  83 
Forwarding  Agents,   112 

Buildings  and  Machinery,  17 
Plantation  Machinery,  58,  59 

Seeds,  97 

Packing  Cases,   114 

Plantation  Machinery,  16,  26,  27,  36, 

37,  62,  63,  124 
Wharfingers,  48,  49 
Plantation  Machinery,  54,  55 
Seeds  and  Stumps,  i 
Seeds  and  Stumps,   107 
Tapping    Knives,    Buildings,    etc.    53 

123 
Tapping  Knives,  78 

Plantation  Tools,  etc.,  44,  45,  46,  47 


Erratum  .•—Pulsometer  Engineering  Co.,  Ltd.,  for  "  Pumps  " 
read  "  Drying  Plant  and  Pumps." 


ADVERTISEMENTS 


Rubbers 


SHOW'S 


IAachinerx 


i 


HAND  WASHING  MACHINES. 


ROLLERS  15in.  x  Tin. 

INVALUABLE    FOR    SMALL    ESTATES    AND 
THOSE    BEGINNING   TO   TAP. 


This  machine  is  a  small  replica  of  our  power  driven  machines, 
but  proportioned  to  minimise  friction  and  to  enable  rubber  to  be 
washed  and  sheeted  by  manual  labour  only.  It  is  supplied  with 
diamond  cut  rollers  for  washing  and  plain  roUers  for  sheeting. 
Easy  running  is  attained  by  the  use  of  double  helical  machine 
cut  driving  gears.  Each  machine  is  fitted  up  with  water  spray 
pipe  and  valve,  guide  plates,  tray,  and  strainer. 

Worm  and  wheel  roller  adjusting  gear  is  fitted  if  desired. 


Two  of  these  Machines   will  deal  with  an 
output  of  1,500  Ihs.  of  Dry  Rubber  per  month. 


FRANCIS    SHAW    &    CO.,    LTD., 


AD  VERTISEMENTS 


Washing    Maghines. 


MADE  IN  TWO  STANDARD,  SIZES. 

18"    X     12"    FOR     lARQE     ESTATES. 
18"     X    9i"    FOR     SMALL     ESTATES. 

OUR  1912  MODELS  COMBINE  ALL  THE  LATEST  IMPROVE- 
MENTS    WITH     THE     BEST     MATERIALS     AND 
WORKMANSHIP. 

TOTALLY     ENCLOSED     ROLLER     ADJUSTING     GEAR 

Working  in  an  oil  bath  inside,  the  frames. 

OUR  IMPROVED  SAFETY  BUSHES  IN  EACH  FRAME 

To  prevent  damage  by  careless  working. 

A    HELE     SHAW    PATENT     FRICTION    CLUTCH 

Operates  the  machines  without  any  shock. 

PATENT  DOUBLE  HELICAL  MACHINE  CUT  GEARING 

gives  maximum  efficiency  minimum  noise. 

ALUMINIUM     HOPPERS    AND     GUIDE     PLATES. 

CAST    IRON    TRAY    WITH    ALUMINIUN    CATCH    PLATE 
AND      STRAINER. 

BRADFORD,    MANCHESTER. 


ADVEETISEMENl  S 


RUBBCEte 


SHOW'S 


IAVachinery  ffli' 


Washing^  Grepeing  &  Sheeting 
Machines. 


Battery  or  Machines  with    Back  Shaft  Drive. 

DRIVING    ARRANGEMENTS. 

WE  supply  our  Machines  with  either  Under  Shaft  or  Back 
Shaft  Drive,  but  strongly  recommend  the  latter,  as  the 
bearings  are  then  quite  clear  of  the  dirt  and  water  from  the 
machines. 

The  line-shaft  is  driven  from  the  Engine  Crank  Shatt  by  any 
of  the  following  methods  : — 

(a)  By  Fast  and  Loose  Pulleys  with  Belt-Shifting  Gear. 
[h)  By  a  Single  Pulley  mounted  on  a  Hele-Shaw  Friction- 
Clutch  on  the  line  shaft.  (This  is  preferable  to  the 
fast  and  loose  pulleys  as  no  shifting  of  the  belt  is 
necessary) . 
(c)  By  Patent  Double  HeUcal  Machine  but  Gearing  direct 
from  the  Crank  Shaft  to  the  Line  Shaft.  In  this  case 
the  wheel  on  the  line  shaft  is  mounted  on  a  Hele- 
Shaw  Friction-Clutch  to  throw  the  shaft  into  opera- 
tion after  the  engine  has  been  started  under  no  load. 
This  method  is  very  useful  where  space  is  a  con- 
sideration, as  the  engine  can  be  placed  close  up  to  the 
machines. 


FRANCIS    SHAW    &    CO.,    LTD., 


AD  VERTISEMENTS 


Universal  Washing   Machine. 


Manufactured  under  licence  from  the  Patentees. 


IF  YOU  WANT  TO  OBTAIN  THE  BEST  PRICE 

FOR  YOUR  BARK  AND  SCRAP 

THIS  MACHINE  IS 

A    Nl 


::o:: 

The  Universal  Washing  Machine  was  one  of  the  outstanding  successes  of 
the  Rubber  Exhibition  at  London  in  1911,  and  the  tests  there  carried  out  have 
led  to  its  adoption  on  a  large  number  of  estates.  It  is  automatic  in  action" 
requires  minimum  attention  and  cleanses  rubber  scrap  and  bark  more 
effectually  than  any  other  machine.  Made  in  three  sizes  as  follows  : — 
Size     B  Will  treat     1120     lbs.  of  clean  scrap  per  day. 

Size     C  ,,         ,,       1680 

Size     D  ,,         ,,       2240  ,,  ,, 

Full  particulars  and  prices  free  on  application. 

::o:: 


BRADFORD,    MANCHESTER. 


10 


AD  VERTISEMEN-TS 


Sham's  Smoker  Goagdator 


HTHE  SHAW  SMOKER  COAGULATOR  induces  coagu- 
lation by  forcing  smoke  through  the  latex  by  means 
of  compressed  air.  Porcelain  tanks  are  employed  to 
assure  cleanliness,  and  these  are  jacketted  to  contain 
water  on  the  outside  which  is  heated  to  enable  the  latex 
to  be  always  treated  at  the  same  temperature. 

MADE    IN   TWO    STANDARD    SIZES. 

[a]  With  three  tanks  each  taking  25   gallons   of  latex 
per   charge. 

{h)  With  three  tanks  each   taking  50   gallons   of   latex 
per  charge. 

Additional   tanks   can   be    added  to    enable    any    quantity 
of  latex  to  be  treated  per  day. 

FULL  PRICES  &  PARTICULARS  ON  APPLICATION. 


FRANCIS    SHAW    &    CO.,    LTD., 


ADVERTISEMENTS 


VACUUM   DRYING   STOVES. 


TWO     VACUUM     DRYING    STOVES    OPERATED    BY    SINGLE    PUMP, 
CONDENSER    AND    RECEIVER. 

There  is  no  doubt  that  with  proper  attention  the  vacuum  process  is  the 
ideal  method  of  drying  rubber,  and  this  contention  is  upheld  by  the  increasing 
number  of  estates  now  installing  vacuum  dryers,  and  the  success  of  those 
already  in  operation.  In  the  Shaw  Vacuum  Dryer  the  operation  is  carried  out 
at  a  low  temperature  which  is  maintained  at  a  constant  level,  and  affects 
equally  the  whole  of  the  charge. 

The  saving  in  time,  labour,  and  space  is  an  important  factor  and  con- 
siderably reduces  the  cost  of  production. 

For  Rubber  Estates  we  make  the  following  special  sizes  : — 


Size 
No. 

No.  of 
Shelves. 

Size  of 
Shelves. 

Space 
Between 
Shelves. 

Approx.  Out- 
put Per  Day 
of  10  Hours. 

2 

8 
8a 

8 

20 
20 
20 

3ft   by  3ft. 
4ft.  by  4ft. 
6ft.  by  4ft. 
8ft.  by  4ft. 

2i 

120  lbs. 
500  ,, 
720  ,, 
960  ,, 

We  recommend  a  single  stove  in  the  first  instance  with  a  Pump,  Con- 
denser, and  Receiver  capable  of  operating  two  stoves,  so  that  a  second  can  be 
added  when  required. 

Belt,  Steam,  or  Electrically  Driven  Puumps  supplied  for  operating. 


-::o:: —     — 


BRADFORD,    MANCHESTER. 


AD  VERTISEMENTS 


1 


RUBBeRr 


SHAW'S 


l^^CHINERX 


HYDRAULIC  BLOCK  PRESSES. 


BATTERY   OF   PKtSSES  WITH   BELT  DRIVEN   PUMP. 

These  are  the  most  compact  and  easiest  presses  to  handle 
for  the;production  of  Block  Rubber. 

The  Rams  of  the  presses  are  double  acting,  to  enable  the 
pressure  to  be  used  for  first  making  the  block,  and  afterwards 
for  lowering  the  platten,  thus  dispensing  with  the  handling  of 
any  loose  parts,  and  eliminating  trouble  due  to  overflow  and 
sticking. 

We  supply  presses  to  produce  any  size  of  block,  but  find 
that  blocks  about  lain.  x  i2in.  x  i^  in.  are  most  favoured  by  the 
manufacturers. 

IIMPORTAMT    NOTICE. 

We  erect,  by  our  own  staff  of  Engineers  in  the 
far  East,  Factory  Installations  complete  for 
dealing  with  any  required  output.  Our  extensive 
experience  is  at  the  service  of  clients,  and  full 
particulars,  plans  and  prices  will  be  submitted 
free  of  charge  on  receipt  of  particulars  of 
requirements. 


FRANCIS    SHAW    &    CO.,    LTD., 


ADVERTISEMENTS 


13 


Water   Supply. 


Belt    Driven    Pump. 


I^^l-T"' "" 


Steel  Tank  and   Tower. 


We  supply  Pumps  and  Tanks   of   all  sizes,   but  have   standardized  the 
foUowins-  for  Rubber  Factories  : — 


Pumps. 


Tanks. 


Size. 

To  Deliver 

A 
B 
C 
D 

500  gallons  per  hour 
1,000 
1,500 
i.ooo 

Size 

Capacity 

12'  dia.  4'  deep 

2,500  gallons 

15'    ..     5'      „ 

5,000 

20'    ,,     6*      ,, 

11,000 

24'    ,,     6' 

16,000 

The  bottom  of  the  tank  is  fixed  at  a  height  of  15  feet  above  the  factory 
floor  level,  unless  otherwise  arranged.  In  some  cases,  where  the  larger  tanks 
are  necessary,  they  are  arranged  to  form  the  roof  of  the  Engine  House  or 
Store  Room,  thus  dispensing  with  the  steel  tower. 

PLANS     AND     ESTIMATES     FOR     COMPLETE    FACTORIES 
FREE    ON    APPLICATION. 


BRADFORD,     MANCHESTER. 


14 


A  D  VER  TISEMENTS 


SMOKING  &  DRYING  SHEDS. 


RuBBEH    Smoking  Hou?.f     r 


IMPROVED     SMOKING     SHED. 

This  is  the  most  approved  type  of  shed  for  surface  smoking.  The  fires 
are  placed  under  the  drying-room  floor,  which  is  arranged  to  allow  the  smoke 
to  pass  through.  Smoke  distributing  plates  are  placed  above  each  fire. 
Expanded  metal  is  fixed  at  the  floor  level  for  the  inlet  of  air,  and  opening  and 
closing  shutters  in  the  ventilator  to  enable  the  current  of  smoke  and  air  to  be 
controlled. 


'^^^^XaC 


RUBBER     FACTORY. 

We  make  a  speciality  of  steel-framed  factory  buildings  which  we  try 
together  in  our  works  before  shipment  to  ensure  all  parts  being  correct.  They 
are  carefully  marked  to  facilitate  erection,  and  are  of  the  most  approved 
design.  Plans  specifications  and  prices  of  factories  of  any  size  will  be 
submitted  free  of  charge. 


-::o::- 


FRANCIS    SHAW    &    CO.,    LTD., 


ADVERTISEMENTS 


15 


RUBBeRs 


AVACHINERy 


Coolie    Lines. 


A    BLOCK    FOR    20    COOLIES. 

We  illustrate  above  our  Standard  Block  of  Coolie 
Lines  for  20  Coolies. 

It  is  designed  on  the  most  up-to-date  principles 
combined  with  the  minimum  cost. 

Each  room  is  10ft.  square  with  a  ventilator  in  the 
roof  and  a  separate  door  and  steps. 

The  floor  is  raised  6ft.  above  the  ground.     All  the 
framework  is  of  steel  with  a  corrugated  iron  roof. 

The  timberwork  can  be  supplied  locally  or  sent 
out  with  the  steelwork  to  suit  requirements. 

DESIGNS    AND    PRICES    FREE 
for  Coolie    Lines   of  any   size  and  to  suit 
local  conditions  in  any  part  of  the  world. 


BRADFORD,    MANCHESTER. 


i6  ADVERTISEMENTS 


Telegrams :—"  WALKERS,"    Colombo,    Ceylon. 


Walker  Sons  &  Co., 


LIMITED. 


COLOMBO    IRONWORKS. 
Colombo  U  Kandy,  Ceylon. 


THE  LARGEST  & 
BEST     EQUIPPED 

WORKSHOPS  in  the  EAST 

for    the    manufacture    of 

RUBBER  &  TEA 
MACHINERY. 

Please  see  Pages  26,  27,  36,  37,  62,   63,  and  last  page. 


LONDON   OFFICE— 36,    Basinghall   Street,    E.C. 


ADVERTISEMENTS 


.  FORMERLY 


Civil,  Mechanical,  &    Electrical    Engineers, 

BANDOENG^    JAVA. 


SPECIALISTS:  Water-Power,    Direct  or  witii  Electrical 
Transmission,  Electric   Lighting. 
Steam  and  Oil  (Diesel)  Engines  and  Gas  Engines. 

Steel   Buildings,  Complete  Tea  &  Rubber 
Factories,   etc.,  etc.,  to  our  own  designs. 

Over  70  Complete  TEA   FACTORIES  supplied  and 
erected  by  us  in  Java. 

Tea  Preparing  Machinery  from  Messrs.  MARSHALL,  SONS 
and  Co.,  Gainsborough;    Messrs.  DAVIDSON  &  Co.,  Ltd., 

Belfast. 

Consulting  Engineers  to  Messrs.  JOHN  PEET  and  Co.,  Batavia  (Sole  Agents). 

Over  85  Turbines  and  Pelton  Water  Wheels 

Supplied,  Erected  and  in  hand. 

SOLE   AGENTS  in  the   Netherlands,  East  Indies,  for:— 

THE    PELTON    WATER   WHEEL   Co., 
San  Francisco,  U.S.A. ; 

THE  UNBREAKABLE  PULLEY  &  MILL  GEARING  Co.,  Ltd., 

London ; 

THE   BELL   ROCK   BELTING   Co, 
Manchester,  England. 


1 8  ADVERTISEMENTS 


ESTABLISHED     1842. 


JOSEPH 

ROBINSON 

&  CO., 

SPRINGFIELD  LANE  IRONWORKS, 

SALFORD, 

MANCHESTER. 

Telegrams:    "OPAL,    MANCHESTER." 
Tel.    No.    783   CITY    MANCHESTER. 


SPECIALITY: 

RUBBER 


WASHING  MILLS. 

ROLLS  from  8  inches  Diameter  by  12  inches  Long, 
to  18  inches  Diameter  by  36  inches  Long. 

WITH    SMOOTH    FINISH     FOR    SHEETING 

HORIZONTAL.    SPIRAL, 
DIAMOND,    AND     SQUARE    CUT    GROOVES. 


ADVERTISEMENTS 


19 


.  .JOSEPH.  . 

ROBINSON 

&  Co, 

SALFORD,    MANCHESTER.  


/JW\ 


Fig.  No.  245. 

No.    4    WASHING    MILL 

-    FOR    BELT    DRIVE, 

Fitted   with    TRAY^    STRAINER^    and 
WIRE    WHEEL    GUARDS. 


Jj 


ADVERTISEMENTS 


JOSEPH  .  . 

ROBINSON 

.  .  &  Co. 


ESTABLISHED     1842. 


TELEGRAMS     -    "OPAL,    MANCHESTER. 


Fig.  No    231. 


o.    4    WASHING    MILL 

WITH    PATENT    CLUTCH 
ON     DRIVING     SHAFT. 


ADVERTISEMENTS 


JOSEPH  .  . 

ROBINSON 

.  .  &  CO., 

SPRINGFIELD    L4NE    IRONWORKS, 

SALFORD. 


Fig.  No'  228. 


No.   4  WASHING    MILL 

WITH         '  ' 
CATCH     BOX    ON     DRIVING    SHAFT. 


AD  VERTISEMENTS 


JOSEPH  .  . 

ROBINSON 

. .  &  CO., 

Tel.  No.   783   CITY,  MANCHESTER. 
Telegrams  :    "  OPAL,    MANCHESTER." 


Fig.   No.  239 

No.     4    WASHING     MILL 

WITH 

WORM     SETTING     GEAR     FOR     ROLL 
ADJUSTMENT. 


A  D  VER  TISEMENTS 


24 


A  D  VERTISEMEN  TS 


o 


^g 


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ADVERTISEMENTS 


*S 


JOSEPH 

ROBINSON  St  eo. 

SALFORD. 


Fig.    Xo.    242. 

DOUBLE      ACTING      PISTON     PUMP 

— :  FOR  :— 
WATER     SUPPLY. 


26  ADVERTISEMENTS 


Telegrams :—"  WALKERS,"    Colombo,    Ceylon. 


Walker  Sons  &  Co., 

LIMITED, 

COLOMBO     IRON\A/^ORKS, 

Colombo  and  Kandy,  Ceylon. 


The  Michie-Goiledge  Latex  Coagulating  Machine. 

See  Reference  on  page  336  of  text  of  this  Book. 

This  machine  is  inexpensive,  simple,  and  eiificient.  It  is  easily 

transported  to  the  vicinity  of  the  tapping  so  that  the  latex 

may  be   treated  immediately  after  being  tapped.      Eight  to 

ten  gallons  of  latex  can  be  coagulated  in  five  minutes. 


WALKER'S    COLOMBO     RUBBER    DRYER 

is  an  acknowledged  success. 

It  has  a  capacity  of  1,000  lbs.  per  day  if  used  in  conjunction 
with  the  M.G.  process. 

If  used  for  dr5nng  crepe  its  capacity  is  approximately  500  lbs. 
per  day. 

WALKER  SONS  &  GO.^  Ltd.^ 

COLOMBO    AND  KANDY,  CEYLON. 

London  Office— AUCKLAND  HOUSE,  36,  BASINGHALL  ST. 


Please  see  pages  16,  27,  36,  37,  62,  63,  and  last  page. 


ADVERTISEMENTS 


27 


Telegrams. -"WALKERS,"    Colombo,    Ceylon. 

Walker  Sons  &  Co., 

LIMITED, 

COLOMBO     IRONWORKS, 

Colombo  and  Kandy,  Ceylon. 


Walker's   Strip    Cutting    Machine. 

Used  in  connection  with  the  Michie-Golledge  Process.     It  cuts 

the  coagulated   Rubber    into    "worms"    or   strips    and  has 

a  capacity  of  about  120  lbs.  per  hour. 


WALKER  SONS    &    CO.,    Ltd.,    have   always  in  stock  in 

Colombo  and    Kandy   a    great    variety    of    Rubber    Estate 

Requisites.     They  can    supply   all  that  is  necessary  for  the 

development  and  maintenance  of  Estates. 

WALKER  SONS  &  GO.^  Ltd.^ 

COLOMBO   AND    KANDY,   CEYLON. 

London  Office— AUCKLAND  HOUSE,  36,  BASINGHALL  ST. 


Please  see  pages  16,  .26,  36,  37,  62,  63,  and  last  page. 


28  AD  VER  TISEMENTS 


RUBBER    MACHINERY. 


TO  PLANTERS,  RUBBER  MANUFACTURERS,  Etc. 

Gentlemen, 

We  think  it  only  fair  to  make  it  quite  clear  to  Planters 
and  others  that  many  years  ago  we  took  over  the 
Rubber  Machinery  business  of  the  late  John  Mills ;  he  was 
the  English  Pioneer  in  this  branch  of  the  Engineering  trade, 
having  established  himself  about  Fifty  Years  ago,  and 
devoting  his  experience  to  specially  designing  machinery  for 
Rubber  Manufacturers.  Both  he  and  ourselves  have,  there- 
fore, had  a  unique  experience  in  the  Washing  and  Preparation 
of  all  kinds  of  Rubbers  by  supplying  the  necessary  Plants  for 
Rubber  Manufacturers  long  before  planting  was  ever  thought 
of,  besides,  of  course,  designing  and  making  complete  Plants  for 
manufacturing  Rubber  Goods  of  all  descriptions.  Prepara- 
tory to  the  trees  in  the  East  coming  into  bearing  we  re- 
modelled our  Washing  and  Preparation  Machinery  to  suit  the 
new  conditions,  and  have  embodied  many  patented  improve- 
ments in  order  that  Planters,  etc.,  should  produce  only  the 
highest  quality  of  Rubber.  We  attribute  our  success  in 
Ceylon,  The  Malay  States,  Dutch  East  Indies,  Africa,  Brazil, 
Mexico,  etc.,  to  the  fact  that  we  know  exactly  what  Planters 
and  others  want  in  the  shape  of  Machinery,  so  that  their 
Rubber  should  command  the  very  best  market  prices. 

In  the  following  pages  we  illustrate  a  few  of  our  special- 
ities, but  we  would  beg  to  solicit  enquiries  from  Planters, 
etc.,  who  are  contemplating  putting  down  Machinery  for  the 
economical  production  of  Rubber  in  all  its  phases,  when 
prices  will  be  given  for  Buildings,  Drying  and  Smoking  Sheds, 
and  the  necessary  Machinery,  including  erection,  on  the  site 
by  competent  engineers. 

We  shall  be  greatly  indebted  to  our  friends  if  thev  will 
kindly  specify  Bridge's  Machinery  and  Heywood  and 
Bridge's  Patent  Friction  Clutches,  Gearing,  etc.,  when  we 
will  give  same  our  personal  attention. 

Assuring  you  of  our  personal  attention  to  your  valued 
commands,  we  beg  to  remain,  Dear  Sirs, 

Yours    faithfully, 

DAVID  BRIDGE  &  CO.,  Ltd. 


P.S.^We  have  just  been  granted  a 
License  to  make  and  sell  The 
"  Universal  "  Patent  Scrap 
Rubber  Washing  Machine  by 
Messrs.  Werner,  Pfleiderer 
and  Perltlns. 


CXmef^  CuLeL^ 


Managing  Director. 
Castleton,  Manchester. 


ADVERTISEMENTS 


29 


—  N.B.  — 
This  is  undoubtediy 
the  finest  Catalogue 
yet  pubiished  in  con- 
n  e  c  t  i  0  n  with  the 
preparation  of   Plan- 

j  atior      and      Crude 

i  Rubber. 


< 


—  N.B.  — 
We  would  malce  it 
quite  clear  that  even 
this  Catalogue  doe: 
not  represent  our 
Latest  Designs  of 
Rubber     Preparation 

Machinery. 


PLANTERS'  CATALOGUE— 200  Pages— Free  on  Application. 


o 


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o 


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3 
O 


The  above  is  a  Phc^T  of  a  Front  Corner  View  of  our  Works;  behind  are  our  Foundries, 
Smithy,  Pattern  Shops,  Joiners'   Shops    etc.  [Covers  7,2(55  square  yards]. 


—  N.B.  — 

We  malce  Complete 

Plants  of    Rubber 

Machinery  for  every 

section  of  the  Rubbe' 

Trade. 

Also  Reclaming 

Machinery. 


—  N.B.  — 

We    mal(e     Gu;tta 

Percha    and    Balata 

Machinery  in  all  its 

Branches.     Also 

Cable  Machinery. 


m 
m 


MANUFACTURER'S  CATALOGUE— 130  Pages— Free  on  Application. 


A  GENTS  : 

Malay  States  —  Kuala 
Lumpur  Engineering 
Works  —  Secretaries  : 
Paterson,  Simons  & 
Co.,  Ltd.,  London, 
Kuala  Lumpur,  Singa- 
pore, etc. 
Kelantan— Duff  Development  Co.,  Ltd.,  London  and  Kuala  Leblr. 


Ceylon  &  Southern  India 
— Colombo  Commercial 
Co.,'  Ltd.,  London  & 
Colombo. 


Dutch  East  Indies — Merrem 
and  La  Porte,  Amsterdam, 
Batavia,  Soerabaia,  Medan, 
Bandjermasin,  Padang, 


LONDON  OFFICE  :— 35,  Queen  Victoria  Street,  E.G. 


3° 


ADVERTISEMENTS 


BRIDGE'S 

MODERN  RUBBER  MACHINERY. 

FOR   MACERATING,   WASHING,  CREPEING   AND 
SHEETING  PLANTATION    AND  WILD   RUBBERS. 


(igi2  Model.) 

N-B. — This  represents  our  Improved  Patent  Machine,  and  is  acknowledged 
by  the  leading  Planters,  etc,  as  the  last  word  on  Washing  Machinery. 


E 
O 


Battery  of  our  direct  driven  Macerating,  Crepeing,  and  Sheeting  Machinery. 
Please  Specify  Bridge's  Machinery.  Send  For  Catalogues — Free. 


PATENTEES     AND     SOLE     MAKERS:— 


DAVID  BRIDGE  &  CO.,  LTD,, 


LONDON   OFFICE  :  — 

35,  QUEEN    VICTORIA  ST.,  E.G. 


RUBBER 
ENGINEERS, 
Norton  Iron  Works, 
CASTLETON,  Manchester. 


A  D  VERTISEMENTS 


31 


BRIDGE'S 

VACUUM  DRYER. 


IMPROVED 
RUBBER 


CO     » 

o:   >. 
u  ■c 

>■  S. 

E 
3 
3 
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> 


(A  SCIENTIFIC  INSTRUMENT  MADE  UN0E!!8TANDABLE). 


3  a 

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S    S 


5.  3 


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o    9 


^3 


(Made  in  VAiiious  Sizes). 

Before  placing  on  the  Market  our  Vacuum  Dryer  we  made  extensive  experiments  at  our  own  Works. 
We  give  full   instructions  to  our   Customers   with   every   Plant. 

BRIDGrS  PATENT  ROBBER  BLOCKING  PRESSES  AND  PUMPS. 


Our  Presses  are  of  a  Special  Design  for  Rapidly  Blocking  and  Extracting  tlie  Rubber  from  the  Box. 
We  malie  them  in  Batteries  to  deal  with  any  quantity  of  Rubber. 


SEND    FOR    CATALOGUES.— FREE. 


PATENTEES    &    SOLE    MAKERS  :- 


RUBBER 


DAVID  BRIDGE  &  CO.,  LTD.,  encnbers 

LONDON  office: —  NortoH  Iron  Works, 

35,  QUEEN  VICTORIA  ST.,  E.c.        CASTLETON,  Manchester. 


32 


ADVERTISEMENTS 


The  DA  COSTA  Patent  "  Rapid  " 

LATEX  COAGULATOR 

BY     A    SMOKING    PROCESS. 

AWARDED     GOLD     MEDAL     AND      DIPLOMA     AT     RIO     JANEIRO. 

Made  in  various    sizes    to  Coagulate    upwards    of  5,000 
g'allons  of  Latex  per  hour. 


SPECIFY     THE 
DA     COSTA     COAGULATOR 


tti  I 


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< 


This  IS   a  photo,  of   an   installation   we   sent   to    :x\c    First    Rubber 

Plantation  in  Brazil.     The  Brazilians  know  full  well  the  Impoitance 

of  coagulating  their  Latex  by   a  smoking  process. 

N.B.— We  have  carried  out  extensive  experiments  on  all  kinds  of  latices 
both  at  our  Works  and  on  the  plantations  by  the  Da  Costa 
System,  with  the  result  that  the  Rubber  is  as  near  like  BraziUan 
Fme  Hard  Para  as  possible,  and  it  is  pronounced  by  experts  to 
be  much  stronger  after  vulcanization  than  that  coagulated  bv 
Acetic  Acid. 


SEND    FOR    CATALOGUE— PEEE. 


SOLE     MAKERS: 


DAVID  BRIDGE  &  CO.,  LTD., 


LONDON    OFFICE  : — 

35,    QUEEN    VICTORIA    ST.,    E.C. 


RUBBER 
ENGINEERS, 

Norton  Iron  Works, 
CASTLETON,  Manchester. 


m 


ADVERTISEMENTS 


33 


PLEASE  SPECIFY  BRIDGE'S  RUBBER  MACHINERY. 
WE  WILL  SEE  YOU  GET  THE  BEST. 


si 

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SEND  FOR  CATALOGUES— FREE. 


34 


A  D  VERJTSEMENTS 


HEYWOOD  S  BRIDGE'S  PATENT 

FRICTION  CLUTCHES. 


WE  ARE  THE  PIONEERS  IN  THE  APPLICATION 
OF  CLUTCHES  TO  RUBBER  MACHINERY  FOR 
BOTH   PLANTERS  AND    MANUFACTURERS. 


£.a 


>  3  g'S' 
J  5.32 


"  2,0 

S  §  g  M.S 

OS    a   Q    0   t^ 


ALL   IN    HALVES). 

Battery    of    Clutches    prepared    lor    Belt    Drivinfr    and    Eenold's    Chain    Driving.    This 
single    order    represents    over    2,000     b.h.p. 


1   & 


This  shows  part  of  a  complete  installation  (the  other  half  being  a  duplicate  of 
tJiat  shown)  of  our  Heywrod  and  Bridge's  Improved  Patent  Friction  Clutches  for  driv- 
ing Stamp  Batteries,  Air  Compresscrs  Pumps,  etc..  in  connection  with  a  large  Gold 
Mine.  The  whole  plant  is  driven)  by  Gas  Engines,  and  the  Clutches  are  so  arranged 
that  any  one  Gas  Engine,  through  our  Friction  Clvtches,  can  be  made  to  drive  any 
particular  unit  —  for  instance,  the  Stamp  Batteries  can  be  driven  by  any 
of  the  four  Engines  The  whole  of  the  Clutches  and  Millwrights'  work  throughout 
have  been  supplied  and  erected  by  us  ou  the  site. 

N.B.— "We  have  been  making  our  Friction  Clutches  for  Users  Engineers,  Machinists, 
etc.,  for  over  20  years,  and  during'  that  period  they  have  been  applied  to  all  IdJida  of 
drives  which  necessitated  stopping  and  starting  whilst  running  at  hUli  and  low  spe«da 
when  giving  out  light  and  heavy  loads  without  any  shock  or  jar  taking  placet 

200  PAGE  CATALOGUES  FREE  ON  APPLICATION. 


PATENTEES  AND  SOLE  MAKERS: 


DAVID  BRIDGE  &  CO.,  LTD., 


LONDON   OFFICE  ; — 

35,  QUEEN  VICTORIA  ST.,  E.G. 


RUBBER 
ENGINEERS 

Norton  Iron  Works, 

CASTLETON,  Manchester. 


ADVERTISEMENTS 


35 


f 


BRIDGE'S  MODERN 

miLLWRIGHTS^   WORK^ 
SHAFTING  and    GEARING^ 
HAULING    PLANTS^  &c.^ 

For    Es-ta.±es,     Mines,    e-tc. 

(ELECTRICAL     &     MECHANICAL). 
BEST     MATERIALS     AND     WORKMANSHIP. 


SEND    FOR    CATALOGUES.— FREE. 


3. 
t 


a 
o 
» 


PHOTO  OF  CLUTCHES,   SHAFTING,   PULLEYS,   GEARING, 
BEARINGS,    BRACKETS,    Etc.,    TAKEN     IN    OUR    WORKS. 


N.B. — We  have  fitted  up  some  of  the  Largest 
WORKS.  FACTORIES,  MILLS, 
Etc,  with  complete  Shafting  and 
Gearing  Installations,  both  in  the  United 
Kingdom  and  abroad. 


PATENTEES    &    SOLE    MAKERS  :- 


RUBBER 
ENQINEERS, 


DAVID  BRIDGE  &  CO.,  LTD., 

LONDON  OFFICE : —  Nofton  Iron  Works, 

35,  QUEEN  VICTORIA  ST.,  E.G.         CASTLETON,  Manchester 


KK 


36 


ADVERTISEMENTS 


Telegrams :—"  WALKERS,"    Colombo,    Ceylon. 


Walker  Sons  &  Co., 


LIMITED, 


COLOMBO     IRONWORKS, 

Colombo   and  Kandy,  Ceylon. 


Golledge's   Hand    Roller. 

This  machine, 'for  which  "Walkers"  hold  the  manufacturing  rights, 
is  simple,  substantial,  and  efficient.  The  coagulated  latex  in  anv  form 
is  fed  into  the  hopper  and  after  passing  through  the  rollers  twice'  I, there 
being  three  rollers)  is  delivered  minus  all  water  on  to  the  table  below  in 
the  form  of  neat  sheets.  The  bearings  of  the  machine  are  carefully 
machined  and  fitted  and  the  fly-wheels  balanced  with  the  result  it  can 
easily  be  operated  by  one  coolie. 
This  hand  roller  is  in  use  on  200  Rubber  Estates. 


WALKER  SONS  &,  CO.,  Ltd., 

COLOMBO    AND   KANDY,  CEYLQN. 

London  Office— AUCKLAND  HOUSE,  36,  BASINGHALL  ST. 
Please  see  pages  i6,  26,  27,  37,  62,  63,  and  last  page. 


AD  VERTISEMENTS 


37 


Telegrams —"WALKERS,"    Colombo,    Ceylon. 


Walker  Sons  &  Co., 


LIMITED, 


COLOMBO     IRONWORKS, 

Colombo    and  Kandy,  Ceylon. 


Walker's  Geared 

Hand    Press. 

By  means  of  gearing 
and  screw  an  enormous 
pressure  can  be  obtain- 
ed witb  but  little  effort. 
The  size  of  the  top  plate 
is  20  inches  by  14  inches. 


For    larger    installations   the 
"  Self-Acting ' '    Rubber  Press 

is  recommended.  This  design 
for  pressing  sheets,  biscuits, 
and  for  blockmg  scrap  crepe 
and  worm.  The  size  of  the 
box  is  24  by  14  by  12  inches 
deep,  and  contains  12  pres- 
sure plates. 


WALKER  SONS  &  CO., 

LIMITED, 

COLOMBO  &  KANDY,  CEYLON. 

London'  Office — 

AUCKLAND  HOUSE, 

35,   BASINGHALL   STREET. 


Please  see   pages  16,    26,    27, 
36,  62,  63  and  last  page. 


38 


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42 


A  D  VERTISEMENTS 


W.  H.  COCHRANE   &  Co.,    Engineers,   110  CANNON 
STREET,  LONDON. 


View  of  Coolie  Lines. 

In  the  above  illustration  we  show  a  double  set  of  lines 
made  ot  steel  framework,  with  corrugated  iron  roof  and 
timber  walls,  doors  and  steps,  well  ventilated  with  lattised 
inlet  above  the  doors,  that  is  protected  by  the  overhang 
of  the  roof,  the  foul  air  outlet  being  a  continuous  ventilator 
on  the  ridge,  as  shown  in  our  sketch. 


SEND   FOR  OUR  CATALOGUE 


OF     OUR     IMPROVED 


Rubber  Plantation  Machinery,  Factories,  etc. 

W.   H.   COCHRANE  &  Co.^ 

-     ENGINEERS,      - 

110,   CANNON   ST.,    LONDON,    E.C. 

And  at  Kuala  Lumpur,  F.M.S.,  and  Medam,  Sumatra. 


A  D  VERTISEMENTS 


43 


TELEGRAMS— 
TEAMINSTER, 
LONDON. 


TELEPHONE- 
AVENUE,  3105. 


HEVEA  STUMPS  SHIPPED  AT  SHORT 
NOTICE  TO  ALL  PARTS  OF  THE  WORLD 

The  following  Certificate  of  delivery  has  recently  been 
received  in  respect  of  an  order  for  50,000  Stumps  from  the 
Nyong  Rubber  Plantations,  Ltd.,  Cameroon,  German  West 
Africa : — 

"  Examined,  counted  and  checked  twice,  by  Alfred 
"Chandler,  for  and  on  behalf  of  Stuart  R.  Cope, 
' '  London — 20/1  i/ii . 

"  H.  P.  Cavill,  for  and  on  behalf  of  the  Nyong 
"Rubber  Plantations,  Ltd.,  acting  under  the 
"instructions  from  F.  Luders,  Esq.,  General  Manager 

20/11  II. 
"Total,  live,  and  in  good  condition,  43,726. 

The  Order  was  for        50,000 

I  Guaranteed  to  deliver  Sound     . . .     37,500   (75  %) 
I  delivered  "  Live  g  in  Goad  Condition,"  43,726  (87^  7o) 

Surplus  over  my  Guarantee      ...     6,226  Stumps  or  12|7o 


Tropical  Seeds  of  all  kinds  supplied  at  short  notice  in  Season  : — 

HEVEA   BRASILIENSIS.  TEA. 

SAPIUM,    SP.  SOYA. 

MAINIHOT,  SP.  COTTON. 

COFFEE,  SP  GREEN    MANURES. 

Specialities  almost  always  in  Stock,  Robusta  &  Maragogipe  Coffees. 

STUART    B,    COPE, 

33  GREAT  TOWER  ST.^  LONDON^  E.G. 

Planting  Pamphlets  sent  on  application.  Post  Free. 


44 


AD  VERTISEMENTS 


e 

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.4  D  VERTISEMENTS 


A  D  VERTISEMENTS 


YATES  &  CO.,  Ltd.,  "v^^orVs!'  Aston  Manor,  Birminghani. 


A  D  VERTISEMENTS 


H131. 


JOHN  YATES  &  CO.,  Ltd.,  AsL  ManorrBirmingham. 


"48 


ADVERTISEMENTS 


METROPOLITAN  &   NEW   CRANE  WHARVES, 

WAPPING     WALL.     E. 


SAMPLING   RUBBER   IN  ONE   OF  THE  SHOW-FLOORS. 


RE-WEIGHING  RUBBER  PRIOR  TO  DELIVERY  FROM  VAULTS. 

WEBER.  SMITH.  U  HOARE.  Wharfingers. 

C!TY     OFFICE  :     7,    MINCING     LANE,     E.C. 


AD  VERTISEMENTS 


49 


METROPOLITAN   &   NEW   CRANE  WHARVES, 

WAPPING     WALL,     E. 


LANDING  RUBBER  AT  NEW  CRANE  WHARF. 


A  RUBBER  STORAGE  VAULT  AT  NEW  CRANE  WHARF. 


WEBER,  SMITH.  S  HOARE.  Wharfingers. 

CITY    OFFICE  :     7,    MINCING     LANE,     EC. 


5° 


ADVERTISEMENTS 


BULL    V/HARF,     QUEENHITHE,     LONDON,     E.G. 


Jbull  Mbarf  is  situated  in  the  heart  of  the  Citv  of 
London,  within  easy  distance  of  ;\fincing  Lane.  This 
whari  has  long  been  recognised  as  one  of  tlie  leading 
warehouses  for  the  storage  of  Rubber  of  all  kinds,  with 
exceptional  facilities  for  the  inspection  and  working  of 
Rubber  Commodious  \'aults,  considered  some  of  the  finest 
in  London,  particulaii\-  suited  to  the  needs  of  Rubber 
storage,  run  under  the  buildings.  Tire  large,  loftv  and 
light  quays,  and  commodious  upper  floors,  are  specialh' 
adapted  for  the  showing  of  all  kinds  of  Ivubber.  and 
there  is  every  facility  for  the  working  and  inspection  to 
advantage  in  all  parts  of  the  buildings  which  are  devoted 
to  tins  produce.  The  Rubber  business  of  Bull  Wharf 
extends  back  to  i8f)0,  at  which  time  the  wharf  had.  with 
its  trees  at  the  side,  a  more  rural  aspect  than  it  presents 
at  the  present  day. 


ADVERTISEMENTS 


51 


It  IS  well  known  and  appreciatcJ  in  the  trade  that 
the  staff  who  handle  the  Rubber  entrusted  to  Bull  Wharl, 
from  their  long  familiarity  witii  all  kinds,  are  experts, 
and  therefore  able  to  discriminate  as  to  the  cliaracter 
and  qualities  of  the  article,  an  advantage  of  no  small 
benefit  to  merchants.  Our  picture  illustrates  tiie  samplmg 
ol  Plantation  liubber  which  now  constitutes  an  increasing 
proportion  of  tlie  imports. 

The  hre  insuiance  premiums  are  the  lowest  current  for 
liublier  floors  and   \-aults. 

The  proprietors  are  at  all  times  jileased  to  show  those 
who  are  interested  o\'er  their  their  premises,  and  thus  enable 
them  to  see  the  ol3\'ious  ad\'anta,ge  of  storing  Rubber  at 
Bull  ^^•harf, 

Telej)hone  Nos.   3583/5   hondon  W'al 


52 


AD  VERTISEMENTS 


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A  D  VER  TISEMENTS  53 


WHEN  YOU  REQUIRE 

ANY  KIND  of  REQUISITE  for 

RUBBER    ESTATES,    and  for 

FACTORIES, 

YOU    MIGHT    KINDLY   SEND   YOUR 
ENQUIRIES    AND    ORDERS    TO   US. 


We  Supply  and  Ship 

TAPPING     KNIVES, 

COLLECTING     CUPS, 
DRIP    TINS. 

DRIP     SPOUTS,  ■   i 

COAGULATING     PANS, 
BUCKETS, 

STRAINERS,     Etc, 

WASHING  &  CREPEING   MACHINES, 
VACUUM     DRYERS, 
biL     ENGINES, 
SUCTION  GAS  PLANTS,  4  '  ' 
SHAFTING,  PULLEYS,       •  >^ 
ETC.,     ETC. 

WE    MAKE   A    SPECIALTY    OF 

COMPLETE  STEEL  BUILDINGS 

FOR    — 

FACTORIES,  TEA  HOUSES,  GODOWNS,  Etc. 


J.     IN.    WOTHERSPOON    &    CO., 

31  (iate,23)  GREAT  ST.  HELENS,  LONDON,  E.G. 

Teleg.  Addir-bss  :  "Weldable,  London." 


54 


ADVERTISEMENTS 


THE    PATENT 

UNIVERSAL  WASHER 

(BRITISH    MANUFACTURE). 


Pulley  Driven   ^Iachixe. 

(See  also  Opposite  Page). 


The  following  is  a  list  of  a  few  Firms  who  have  adopted  this  Machim- — 
THE  BORNEO  COMPAXY.   Ltd. 
CONSOLIDATED   MALAY  ESTATES,   Ltd. 
THE  DAMANSARA   RUBBER  CO.,   Ltd. 
LANADRON   RUBBER  ESTATES.   Ltd. 

(Lanajron  and   Jementah    Estates). 
LIXGGI   PLAXTATIONS,   Ltd. 
RAYIGAM  ESTATES.   Ltd.,  Ceylon. 
ROSEHAUGH    TEA   &    KUBI3ER   CO.,  Ltd. 
ST.  GEORGE'S  RUBBER  ESTATES.  Ltd. 


Werner,  Pf ieiderer  &  Perkins,  Ltd. 

ENGINEERS, 
WESTWOOD  WORKS,  PETERBOROUGH,   England. 

Telegraphic  Address :    Arktos,    Peterborough. 


ADVERTISEMENTS 


55 


THE    PATENT 


UNIVERSAL  WASHER 

(BRITISH    MANUFACTURE). 


BIRDS-EYE      VIEW 

SHOWING   FRICTION   CLUTCH    GEAR    DRIVEN   WASHING   MACHINEl 

{See  also  Opposite  page). 


Thoroughly  Cleanses  ail  Rubbers  and  Removes  Bark  and  New  Wood  without 
Breaking  or  Splintering.  Cleanses  the  Sandiest  Rubbers  Perfectly  and 
very  Rapidly.      Removes  all  traces  of  Acid. 

When  enquiring  please  send  sketch  showing  position  .of  your  driving  shaft  relative  to 

floor  level,  also  give  the  diameter,  speed  and  running  direction  so  that  detail  plan  can 

be  sent  with  quotation. 


Werner,  Pfleiderer  &  Perkins,  itn 


J 


J 


ENGINEERS, 
WESTWOOD  WORKS,    PETERBOROUGH,   England. 

TelegrapMc  Address :    Arktos,  Peterborough. 


56 


A  D  VERTISEMENTS 


JOHN  GORDON  &  Co., 

9  NEW  BROAD  STREET, 

LONOON, 

Manufacturers   of   every   description    of 
Plantation   Machinery 

FOR   TREATING 

ROBUSTA,  ARABIAN  or  LIBERIAN  COFFEE. 


^ 


Telegraphic 
Address — 
"  Pulper, 
London." 


Established 

over 
50  Years- 


COFFEE     PULPERS, 
WASHERS, 
DRYERS, 
HULLERS, 
GRADERS. 
ALSO    MACHINERY    FOR    TREATING 

Cacao,    Sugar 

and  Rice. 

Write  for  Catalogues,  Estimates  and  Plans. 


^, 


ADVERTISEMENTS 


57 


JOHN  GORDON  &  CoT^l 

9  NEW  BROAD  STREET, 
r.ONI>ON^, 

Sole  Manufacturers  of  H.  S.  SMITH'S  Patent 

Rubber   Centrifugal    Machine. 


Telegraphic 

Address — 

"Pulper, 

London." 


Eitabliihed 

over 
50  Years. 


This  Centrifugal  Machine  produces  direct  from 
the  Latex,  Pure  Sheets  of  Rubber  in  10  Minutes 
without    any    other     manipulation    whatever. 

For  description  see  Page  338. 

Equally  Suitable  for  Treating 

HEVEA,    FUNTUMIA,    CEARA    or 

CASTILLOA     LATEX. 

WRITE    FOR   ILLUSTRATED    PAMPHLET. 


58 


ADVERTISEMENTS 


'CHULA' Patent  RUBBER  DRYING 
and  SMOKING  PLANT. 

FOR  PRODUCING    EITHER    PALE  OR   SMOKED    RUBBER 
WITHOUT    ALTERATION    TO    PLANT     


If  Dries  large  quantities  of  Rubber  at  a  time,  using  a  slow  moving 

current  of  air  or  smoke  at  a  temperature  of  lOo"  to  iio°  Fahr. 
1[  With  our  method  of  sub-divided  Drying  Room  a  day's  production 

of  Rubber  can  be  turned  out  ready  for  packing  e\ery  day. 
*'•  Can  easily  be  apphed  to  existing  Factories  vchere  Drying  Room  is 

available. 
H  Cheap  in  first  cost  and  in  working. 
H  Further  particulars  and  estimates  for  installation  sent  on  receipt  of 

plan  of  existing  Factory. 
T  These  plants  are  now  working  in  Ceylon,  South  India,  and  F.il.S. 


SOLE     MANUFACTURERS  : 

Tyneside  Foundry  &  Engineering  Co., 

Head  Office  and  Works  : 

ELSWIGK,    NEWCASTLE-OM-TYNE. 

Telegrams:   "FOUNDRY,  Newcastle-on-Tyne.  " 
Code  :  A  B  C,  5th  edition. 


ADVERTISEMENTS 


59 


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A  D  VER  TISEMENTS 


Merry  weathers'  Spraying  Apparatus 

FOR    RUBBER    PLANTATIONS. 


F,^.  No.  -^oJX- 


Merry  weathers'  Patent  Petrol-driven  ■  Ravensbourne"  Pump  at  work 
on  a  Rubber  Plantation. 


MERRY  WEATHERS'  are 
manufacturers  of  every  des- 
cription of  Apparatus  for  Spray- 
ing by  fiand  or  power  for  small 
or  large  Plantations,  and  are 
willing  to  give  expert  advice  on 
learning  particulars  of  local  con- 
ditions and  special  requirements. 


Merryweathers'  Light   Handworked 
Spray  Pump. 


Write  for   ILLUSTRATED    PAMPHLET    (Xo.    508    R.W.R.)    dealing 
completely  with  the  whole  subject. 

IVIERRYWEATHER     &    SONS^ 

GREENWICH,    LONDON,    S.E. 


A  D  VERTISEMENTS 


6i 


Mcrrywgatkrs'   Light   Portable 
" Valiant"  Steam  Pump. 


Will  Pump  ioo  Gallons 
per  minute. 

Boiler    can   be   arranged 

TO  BURN  coal,    WOOD,    OR 
LIQUID    FUEL. 

Weight  6i  cwts. 

The  "Valiant"  is  suitable 
for  general  plantation 
Work,  also  for — 

Emptying  Drains, 

Irrigation  by 
Artificial  Rain. 

Fire  Extinction, 
&c.,  &c. 

Will     also     drive     Light 
\  Machinery  by  belt  from 

fly-wheel. 

The  most  Useful  Appli- 
ance a  Planter  can 
purchase. 

Perfectly     Safe     in     the 

HANDS         of        unskilled 

native    labour. 


Merryweathers'  "  Variant "  Steam  Pump  with  liglit 
two-wheeled   detachable   Carriage. 


The  "Valiant"  can  be  wheeled  about  by  one  man. 
Can  be  carried  by  poles  on  the  shoulders  of  8  men. 
Hundreds  in  constant  use  in  all  parts  of  the  World. 


A   Customer  in  Selangor  writes  : — 

"The   "Valiant"   Engine    which  I  have  been  using  lor 
years  has  given  me  more  than  satisfaction  always." 


Write  jar  Ilhisirated  ramphhi  No.  738  M.W.R. 

MERRYWEATHER    &    SONS^ 

GREENWICH,    LONDON,    S.E 


62  ADVERTISEMENTS 


Telegrams :—"  WALKERS,"    Colombo,    Ceylon. 


Walker  Sons  &  Co., 

LIMITED, 

COLOMBO     IRONWORKS, 

Colombo  and  Kandy,   Ceylon. 


In    addition    to    their    own     facilities     for     manufacturing 

machinery  for  Tea  and  Rubber  Estates  WALKER    SONS  & 

CO.,  Ltd.,  hold  the  following  important  Agencies  : — 

Marshall  Sons  &  Co.,  Ltd  ,       ...     For  Engines,  Boilers,  and  Tea 

iWachinery. 
The  National  Oas  Engine  Co.,        For  Producer  or  Suction  Gas 
Ltd.  and  Oil  Engines. 

Babcock  &  Wilcox,  Ltd.  ...     For  Water  Tube  Boilers 

Francis  Shaw  &  Co.,  Ltd.  The    well=known     English 

makers  of  Rubber  Machin- 
ery. 

F.  Reddaway  &  Co.,  Ltd.  ...     For  Belting. 

R.  Waygood  &  Co.,  Ltd.  ...     For  Lifts  and  Cranes. 

Bullivant  and  Co.,  Ltd.  ...     For  Wire  Shoots,  Wire  Ropes, 

&c. 

Blackman  Ventilating  Co.,  Ltd....  For  Fans,  &c. 

T.  Firth  &  Sons,  Ltd For  Tool  Steel  &  Steel  Castings 

North  British  Mercantile  Insur- 
ance Co FIRE. 

North  British  Mercantile  Insur- 
ance Co LIFE. 


WALKER  SONS  &  GO.^  Ltd.^ 

COLOMBO   AND    KANDY,  CEYLON. 

London  Office— AUCKLAND  HOUSE,  36,  BASINGHALL  ST. 


Please  see  pages  16,  26,  27,  36,  ^7,  63,  and  last  page. 


ADVERTISEMENTS 


63 


Telegrams —"WALKERS,"    Colombo,    Ceylon. 


WALhER  SONS  &  CO.,  Ltd., 

COLOMBO  IRONWORKS,  Colombo  and  Kandy,  Ceylon. 


SHEWING  GOLLEDGE'S  HAND  ROLLER  IN  OPERATION. 

WALKER  SONS  &  CO,  Ltd,  kanTTeW 

London  Office— AUCKLAND  HOUSE,  36,   BASINGHALL  STREET. 
Please  see  pages  16,  26,  27,  36,  37,  62,  and  last  page. 


64 


ADVERTISEMENTS 


CAILLET'S  MONO-RAIL 


For 
Rubber  Estates. 


Oh  P 

ci   -^ 

OJ   r-; 


^  o 


Rail  with  Sole  Plates  and  Fish  Plates  in  position 


Portalile  Ramp  or  Switch  for  temporary  use>n  curves,  etc. 


Crossing  Plato  tor  lines  running  at  right  angles. 


ADVERTISEMENTS 


65 


CAR,  TYPE   33,   BEING    USED    ON   A   RUBBER   PLANTATION   IN 
MALAY   PENINSULA. 


MONORAIL,     TYPE     47. 


65 


ADVERTISEMENTS 


Colombo  Commercial  Co.^  Ltd.^ 


Engineers  &  Building  Contractors. 


COLOMBO. 


BBBSSggja iiliiiia£.^    SSSSmiP 

>.    '^^^^te..^^K 

^-  P^^^.^^^^^y^^ 

■J^^f^S 

P-^^^^!^^g^^|^B 

Pl^^^S 

s^^^^MiaM 

Manufacturers  of :—  WORKSHOP   INTERIOR. 

C.C.C.  HOT  AIR  RUBBER  DRYING  APPARATUS. 
PELTOM  WHEELS.        AERIAL  ROPEWAYS. 
STEEL   STRUCTURAL   WORK   FOR   FACTORIES,  COOLY 
LINES  and  for  all  types  of  ESTATE  BUILDINGS. 


■:-.:'U  :"-'■:•:. ''^:.'^(^-    i    :'.    :.''' 

->'"i;-^ 

^^^^^^^L                                            ~ -?..'*J?r-^ —  '  ■ — — ■' ^»fc  -"■ 

■HIp''-  - ^      ■  -'"•      \-4^^^^  1  JWIJ 

i 

Agents  for:—  STRUCTURAL   STEEL   YARD. 

TANGYE'S  SUCTION  GAS  PLANT. 

DAVID  BRIDGE  &  Co.'s  RUBBER  MACHINERY. 


A  D  VERTISEMENTS 


67 


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68  AD  VER  TISEMENTS 


RECORD    CROPS 

—  BY  — 

FREUDENBERG  S  Co.'s 

Special  Fertilisers 

—  FOR  — 

RUBBER,    TEA,     COCOA,    COCONUTS,    Etc. 


Bone  Meal.  Concentrated 
Crushed  Bones.  Superphosphate. 

Ground  Nut  Cake.  Good  Ordinary  Basic  Slag. 

Rape   Seed  Cake.  Extra  QuaUty  Basic  Slag. 

Nitrate   of    Potash.  Gjrpsum. 

Sulphate  of   Ammonia.  Best  Indian  Fish  Manure. 

Castor  Cake.  Peruvian  Guano. 

Patent  Steamed  Bone  Dust.  Freshly  Burnt  Lime. 

Nitrate  of  Soda.  Blood    Meal. 

Superphosphate.  Precipitated  Phosphate  of 

Lime. 


SOLE    AGENTS    OF 

THE    GERMAN    POTASH     SYNDICATE. 

Kainit,  Muriate  &  Sulphate  of  Potash,  &  all  other  Potash  Salts. 

NORTH    WESTERN    CYANAMIDE   Co.,   Ltd., 

Nitrohm. 


(Buaranteeb  analyses.         Soils   Hnali^seb. 

PLEASE    ASK    FOR    QUOTATIONS. 

Freudenberg  &  Go.^  Colombo 

Manure  Works:  HULTSDORF  MILLS. 
Offices:     PRINCE   STREET,   FORT. 


ADVERTISEMENTS 


AD  VERTISEMENTS 


BERTRAMS  LIMITED 

Engineers^ 
SCIENNES,    EDINBURGH. 

MAKERS    OF    ALL    KINDS    OF     


Plantation   Rubber    Machinery 


Rubber  Machines 
at  Singapore 
Exhibition  1910, 
Awarded  First 
Prize  and  Goid 
iHedal. 


If  for  the  MALAY  PENINSULA  Send  to 

RILEY,  HARGREAVES  8  Co.,  Ltd.,  Engineers.  SINGAPORE. 

Our  Sole  Agents  there. 
If  for  CEYLON  Send  to 

GEORGE  ROBSON  8  Co.,  COLOMBO, 

Our  Sole  Agents  there. 


ADVERTISEMENTS 


71 


Complete  Installation  for  the 
Preparation  of  the  Crude  Rubber, 

Tapping  Knives,  Collecting  Cups,  Coagulating 
Utensils,  Coagulating  Chemicals,  Rubber  Rolling 
Mills,    Drying    Plants,     Blocking    Presses,    etc. 


flgricultural 
Implements. 


Tools  of  the 


TRADE   MARK. 


Patented  Process  for  Extracting  Caoutchouc  out  of  Poor  latex. 

EXTREMELY     PROFITABLE. 

CARL  SGHLIEPER,   Remscheid. 
CARL   SCHLIEPER,    Batavia. 

CARL  SCHLIEPER  Gebrs.,  Semarang. 
CARL  SCHLIEPER  &  Co.,  Soerabaia. 


ImpiementsTapping  Knives 
finest  Quality 


72  AD  VERTISEMENTS 


PASSBURG'S 

VACUUM  DRYERS 


SPECIALITY  :- 

HEATING  SHELVES  with  WELDED  EDGES 

Ensuring  Thorough  Drainage  of 
Condensed  Steam  and  Air,  and 

HIGHEST     EFFICIENCY. 

Nearly  3^000  in  use. 

OVER    350    SUPPLIED    TO 

RUBBER  WORKS  and  PLANTATIONS. 


The  ^^PASSBURC  DRYERS  embody 
all  the  improvements  suggested  by  over  35 
years'  experience  as  DESIGNER, 
MANUFACTURER  &  USER  of  Vacuum 
Drying  Plant. 

OVER  35,000  TONS  of  Washed   Rubber  are  annually  dried 
in  the  "PASSBURG"  Chambers. 


Full  Particulars  from  : — 

JAIVIES   LIVINGSTON,    M.I.IVIech.E., 

DRYING    EXPERT, 

Representative  for  the  United  Kingdom  and  Colonies, 
30,  Great  Saint  Helens,  LONDON,  E.G. 


ADVER  T I  SEMEN  TS 


73 


We  were  making  and  advertising  Rubber  Machinery  in  1854, 


UFT  HAND  BATTERy 


T^.JV^.C      TYPE 


111  ftaliirlu  Gai  Igr  Cu  .!>  Oil  etiKi  Dim 


T.  J.  W.  CLARKE,  L™  ^^ai 


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ENGINEERS 

RUBBER   PLHNTATION 
MACniNERy    MAKERS 


HaVELOCK      IljON      WoiiKS. 

LiEICESTEIl 


TITACERHTOR. 


O 


M.M.S.   TYPE   BATTERY. 

ttrt    HAND  SECTION   OF   A   SIX   MILL   BATTERY  RIGHT   HAND    SECTION    OF    A    SIX    MILL    BATTERY 


SELLING   ACCNTS; 


JKcjir.    SOUSTEAD   6    Co..    Sl-gppon  anJ  Vcnang. 

■JWcjin    SOUSTEAD  'HJIM'PSHITin   &    Co.,  Lid.  Kuah.  Lumpur,  F.MS 

JlTr.."     l-l\"nETF\r'i   STOKHS.  .S-HFornrx.  Sotraioa.  JImihlJam. 


74 


A  D  VER  TI  SEME  NTS 


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ADVERTISEMENTS 


IMPROVED  PLANTATION 
RUBBER    MACHINERY. 

ROLLER  MILLS  for   dehydrating  the  Latex. 
ROLLER  MILLS  for  Washing  the  Crude  Rubber. 
BLOCK  RUBBER  PRESSES,  Etc. 

Complete  Machinery  for  INDIA  RUBBER,  GUTTA 
PERCHA,     and    CELLULOID     MANUFACTURE 

on  the  most  modern  principles. 


FRIED.KRUPP,A.G. 

GRUSONWERK. 

MAGDEBURG— BUCKAN. 

Sole  Agent  for  Great  Britain  and  Ireland— 
VSf.    STAMM, 

25,  COLLEGE  HILL,  CANNON  STREET,  LONDON,  E.C. 

^ J 


76 


ADVERTISEMENTS 


i.mn'i^moM(iM 


A  D  VERTISEMENTS 


77 


HENBY  BERRY  &  CO.,  Ltd.,  [[[DS.  Engliiiid. 

specialities— RUmER  PLANTATION  MACHINERY. 
RUBBER   FACTORY  MACHINERY. 
HYDRAULIC  MACHINERY  &  TOOLS. 


Estimates  Given  for  Complete  Plants  and  Single  Machi 


HAND   AND   POWER    DRIVEN.  a  BELT     DRIVEN 

I  PLANTATION  RUBBER  WASHERS.  —  CREPERS.  —  MACERATORS.  —  SHEETER8. 


BELT     DRIVEN   HYDRAULIC 
PUMP. 


PATENT  RUBBER    CORD  TUBE  AND  TYRE 
FORCING     MACHINE. 


HYDRAULIC    VULCANIIING 
PRESS    AND    INTENSIFIER. 


SCREW  TYPE  BELT  VULCANIZING  PRESS. 


AD  VERTISEMENTS 


ADVERITSEMENTS  79 


COMPLETE    INSTALLATIONS 
FOR    ESTATES. 

STEEL-FRAMED  FACTORIES. 
SMOKE  AND  DRYING  HOUSES, 
COOLIE  LINES  &  BUNGALOWS. 
PUMPS,  TANKS,  FILTERS,  AND 
STERILISING  APPARATUS  FOR 
ESTATE  WATER  SUPPLIES. 
ERECTED  ANYW^HERE  IN  THE 
EAST. 

♦■♦■♦■♦■»■♦•»■♦' 
SPECIALISTS    IN 

PUNTATION  RUBBER  MACHINERY. 

Designs  and  Estimates  Submitted  Free. 


RILEY  HABGBEAVES&Co.,Lt[l.. 

ENGINEERS, 

SINGAPORE  and  Branches, 


Telegrams — "  Hargreaves." 


8o 


ADVERTISEMENTS 


RUBBER    HYSTERESIS    TEST: 

Prof.  Schwartz,  Professor  of  Elec- 
trical Engineering  at  the  Victoria 
University,  England,  has  invented 
a  Rubber  Testing  Machine  whereby 
the  Hysteresis  of  Rubber  is  auto- 
malicall\-  recorded  on  paper.  The 
Extension  Curve  and  Hysteresis 
Loop  assume  definite  shapes  for 
particular  grades  and  qualities  of 
Rubber,  and  therefore  specimens 
may  be  standardized  for  compari- 
son \\  ith  other  samples. 

The  Machme  is  manufactured  under 
authorit\'  Irom   Prof.  Schwartz  by 

G   CUSSONS,  Ltd., 

The  Technical  Works, 

MANCHESTER 
AND 
231,  STRAND, 

LONDON,  W.C. 


The  make  of  the 
Machine  is  of  the 
highest  possible 
excellence.  All 
Pulleys,  Screws, 
and  mo\'ing 
parts  are  speci- 
ally; .designed, 
being  rigid  and 
highly  sensitive. 
The  Frame  is  of 
best  mahogany, 
polished. 


All  requisite 
accessories  are 
included  with  the 
Machine,  viz.. 
Brass  Standard 
Cutting  Appar- 
atus, Special 
Cutting  Knife, 
Guages,  Clamps, 
Tools,  e'c. 


Price  complete  £23. 

See  reference  to  this 
experiment  on  Page 

No.  453. 

Size  approx.,  6ft.  by 

3fi-  by  ift. 


ADVERTISEMENTS  8i 


1 


RUBBER  DRYING 


ON   THE 


-*-H-*- 


NORMAIR    SYSTEM 

-« V >- 

(MARLOW'S     PATENTS). 


No   risk   from   over-heating. 
Rapid   in   operation. 
Easy   to   regulate. 
Easy   to   run. 
Economical. 

WRITE     FOR'  LIST     No.     503. 

ESTIMATES    AND    PLANS    FOR    DRYING    RUBBER    OR 
OTHER    COLONIAL    PRODUCE     ON     APPLICATION. 

putsometer  Cnginccrinsi  G?,  II! 

LONDON:  READING: 

irJ  OFFICES :  WORKS : 

11,  TOTHILL  STREET,  S.W.        NINE  ELMS  IRON  WORKS. 


82 


ADVERTISEMENTS 


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PLANTATIONS  &  TREES  WIT 

IPPLICATION    TO    THE    SOLE  MaNUFA 

5,   CROSS    STREET, 

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ADVERTISEMENTS  83 


Pests   on    Rubber. 

For  30  years  Messrs.  Strawsons  have  made  a  speciality  of  Insecticides 
and  spray  fluids — having  the  largest  and  oldest  business  of  their  kind 
in  Europe. 

The  following  three  chemicals  are  of  standard  international  reputation 
and  should  be  used  on  all  rubber  plantations  (from  which  highly  satisfac- 
tory testimonials  are  being  received.) 

(1).    For  leaf-eating  or  gnawing  insects  and  caterpillars. 

Strawson-Swift  Arsenate  o'f  Lead  paste  destroys  in  a  few  hours 

all  leaf-eating,  chewing,  or  gnawing  insects. 

It  is  the  standard  Arsenical  spray  fluid  of  the  World.     It  adheres 

to  the  plant  for  many  weeks — and  withstands  heavy  rains.     It 

does  not  scorch  the  foliage — it  mixes  readily  with  cold  water.     It 

is  applied  with  an  ordinary  sprayer  in  the  visual  way. 

Price  yd.  net  per  lb.  in  loo-lh.  kegs. 

(2).    For  Fungus  Diseases. 


Strawsonite  concentrated  Bordeaux  Mixture  is  the  mqst  powerful 
Fungicide  with  which  we  are  acquainted  for  dealing  with  Fungus 
diseases  of  rubber. 

The  use  of  Strawsonite  avoids  the  labor,  trouble,  and  danger  of 
preparing  the  Bordeaux  Mixture  upon  the  plantation.  Moreover, 
there  is  a  great  saving  in  freight  as  no  Lime  is  required  (one  ton 
Sulphate  of  Copper  plus  J-ton  Lime  only  makes  about  i  ton  Straw- 
sonite— the  difierence  in  weight  being  given  off  in  steam.) 
Strawsonite  is  a  uniform  powder  guaranteed  to  contain  the  copper 
equivalent  of  pure  Sulphate  of  Copper  itself,  viz  : — 24%  to  25% 
metallic  copper. 

Packed  in  50/6.  and  100/6.  bags. 
Fluctuating  prices  on   application. 

For  Icilling  weeds. 


Soluble  Brand  Sulphate  of  Copper  is  very  extensively  used  for 
destroying  weeds  (also  for  making  home-made  Bordeaux  Mixture) . 
Soluble  Brand  is  guaranteed  99%  pure,  and  is  prepared  by  a  special 
process  which  renders  it  immediately  soluble  in  cold  water.  It 
does  not  ' '  cake. ' '  Soluble  Brand  is  greatly  superior  to  the 
ordinary  crushed  or  powdered  grades  of  Sulphate  of  Copper, 
which  take  a  much  longer  time  to  dissolve,  and  which  are  liable 
to   ' '  cake. ' ' 

Packed  in  ^olb.  and  100/6.  bags. 
Fluctuating  prices   on   application. 
Ask  for  Booklet,  Leaflets,  etc. 


Strawsons  <S  Company, 

WHOLESALE  &  EXPORT  CHEMISTS. 

Dept.  R,  79,  Queen  Victoria  Street,  London,  Eng. 


84 

ADVERTISEMENTS 

NES. 

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ADVERTISEMENTS 


85 


LATEX 

FOR    ALL     UPTO-DATE 

RIBBER  PLANTATION  REQUIREMENTS. 

FACTORIES  SUPPLIED  COMPLETE. 


WASHING   &    CREPEING    MACHINE    WITH    LATEST    IMPROVEMENTS. 


£atex  engineering  Co.  || 


Works  and  Head  Office — 

Manchester   Road,   Droylsden,  Near   Manchester. 

Town  Office — 65,  Bridge  St.,   Manchester. 
prices  and  specifications  on   application  to  head  office. 


86  ADVERTISEMENTS 


Tropical  Agriculturist 

AND  MAGAZINE  OF  THE  CEYLON  AGRICULTURAL  SOCIETY 

[Commenced  June,   1881.) 

A  Monthly  Magazine  of  Information  regarding  Products 
suited  for  Cultivation  in  the  Tropics.  Rubber,  Tea,  and 
Coconuts  freely  written  up.  Much  information  published  on 
Minor  Products. 

The  "  Tropical  Agriculturist ' '  has  an  assured  position  in  its 
large  circulation  in  Ceylon,  Southern  and  even  Central  and 
Northern  Iniia,  the  Straits  Settlements,  Sumatra,  Java, 
Borneo,  Northern  Australia,  Queensland,  Natal,  West  Africa 
Mauritius,  Southern  and  Central  States  of  America,  Brazil 
and  the  West  Indies. 

As  a  medium  for  English,  American,  Australian  and  Indian 
advertisements  of  Goods  suitable  for  the  tropics,  and  for  aU 
connected  with  Agriculture,  the  "  Tropical  Agriculturist ' ' 
stands  unrivalled,  the  work  being  constantly  in  the  hands  of 
Native  as  well  as  European   and  American    Agriculturists. 

SUBSCRIPTION  :     £1     PER    ANNUM,    POSTAGE    INCLUDED. 

Weekly  Ceylon  Observer. 

The  Ceylon  Paper   for  Home  and  Abroad. 

A  General  Summary  of  the  daily  Ceylon  Observer  published 
Weekly  on  the  day  upon  which  the  Overland  Mail  is 
despatched,  and  contains  an  Epitome  of  Occurrences  in  Ceylon, 
including  Government,  Civil,  Military,  Mercantile ,  Planting 
and  Religious  affairs ;  Domestic,  Shipping  and  General 
Intelligence. 

A  special  feature  of  the  Weekly  Ceylon  Observer  is  the  very 
full  and  complete  Commercial  Intelligence  given,  enabling 
Proprietors,  Brokers,  and  Dealers  at  home  to  ascertain  the 
condition  and  prospects  of  Ceylon.  Produce  and  Estate  Crops. 
Much  information  given  each  week  regarding  Rubber,  Tea,  etc. 

£1     4s.    PER    ANNUM     IN     ADVANCE. 

A.    M.    &   J.    FERGUSON, 

Publishers  and  Proprietors, 

Colombo,  CEYLON. 

LONDON  :— MACLAREN  &  SONS,  Ltd., 

37  &  38,  Shoe  Lane,  E.C. 


ADVERTISEMENTS  87 


Books  for  Tropical  Planters. 


ALL  Planters  in  Tropical  and  Sub-tropical  countries 
should    write    for    a    copy    of  our  Catalogue  of 
Books     on    Tea,     Rubber,     Coconuts,     Coffee, 
Cotton,  Cocoa,  Cinnamon,  Camphor,  Tobacco,  Pepper, 
Cinchona,  Fibres,    Palms,  Cardamons,  Vanilla,  Wattles, 
etc. 

"Hevea  Brasiliensis,  or  Para  Rubber,"  by  Herbert  Wright. 

"Science  of  Para  Cultivation,"  by  Herbert  Wright. 

"Tea  Pruning  and  Kindred  Subjects,"  by  Ed.  Hamlin. 

"  Fertilization  of  Tea,"  by  G.  A.  Cowie. 

"Bulletins  of  the  Indian  Tea  Association." 

"Theobroma  Cacao  or  Cocoa,"  by  Herbert  Wright. 

"Coconut  Planters'  Manual,"  by  J.  Ferguson. 

"  Coffee  Planters'  Manual,"  by  J.  Ferguson. 

"  Cinchona  Planters'  Manual,"  by  T.  C.  Owen. 

"  Handbook  of   Tropical  Qardening  and  Planting," 

by  H.  F.  Macmillan. 


IMPORTANT     FOR    PLANTERS     IN    CEYLON, 
INDIA    AND     MALAYA. 

"Inge  Va"  Tamil  Handbook, 
"Niehe  Varen"  Sinhalese  Handbook. 

Apply  to — 

A.    M.    &    J.    FERGUSON, 

Publishers  of  "  Ceylon  Observer  "  (Daily  and  Weekly). 

"Tropical  Agriculturist  "  and  Magazine  of  the  Ceylon 
Agricultural  Society  (Monthly), 

"Ceylon  Handbook  and  Directory"  (Annual),  etc.; 

or  to — 

MACLAREN    &    SONS,    Ltd., 

37  &  38,  Shoe  Lane, 

LONDON,  E.C. 


A  D  VERTISEMENTS 


Established    1884. 


1     ■       The  Leading  Financial  Daily  uf  the  fVorhL        1 

Jhs  financial  tKsws 

THE     GREAT    CITY     DAILY. 

THE  FINANCIAL  NEWS    has  the  largest  circulation  of  any  financial 
newspaper  in   the  worlcl. 


ALL  THE  NEWS  OF  ALL  THE  MARKETS. 


Special  Industrial  and  Mining  Intelligence. 
Special  Legal,  Banking,  and  Insurance  Notes. 

Page  2  every  day  of  THE  FINANCIAL  NEWS  contains  the  best 
Rubber  Share  Market  report  and  other  Rubber  News. 


RUBBER    MARKET    MOTES 

appear  every  Friday,  and  include  unbiassed  comment  on  current  events. 


Publishing,  Advettisevient,  and  i^dHm-ial  Ojjiccfi:  — 

111,  QUEEN  VICTORIA  STREET,  LONDON,  E.G. 

BRANCH     OFFICES  :— 

New  York,  Paris,  Berlin,  Rome,  Malta,  Cape  Town,   Johannesburg, 
Perth,  W.A.,  Dublin,  Glfisgow,  and  Edinburgh. 

Telegrams  — '*  Fiiu'ira,  Loiuhmy  TcU'plt(nie — 3S71  Ccuh-al  S^if  <C-  L^Ni  i'itfi. 


THE    FINANCIAL    NEWS 

IS  PUBLISHED  DAILY   IN  FRENCH   IN  PARIS. 
Offices— 36  bis  BOULEVARD   HAUSSMANN. 

Telegrams — "  l-'ineirs,  Paris  "  Tch'[)hone — S-JH/'S. 


ADVERTISEMENTS  89 


THE  LARGEST 

MANURE  WORKS 

IN  THE  EAST! 


Rubber  Fertilisers 

A   SPECIALITY. 


3for  C.3.]f.  prices  an&  Daluable  3nformation 

—   APPLY     TO  — 

THE  CEYLON  MANURE  WORKS. 
A.   BAUR  

COLOMBO.        CEYLON. 


MANURE    ANALYSES 
GUARANTEED. 

MANY     YEARS 

EXPERIENCE. 


Well  Balanced  aad 
Effedive  Mixtures,  the 
result  of  Laboratory 
Research  and  Extensive 
Experiments  on  Rubber 
Estates. 


go 


ADVERTISEMENTS 


THE 

'Hutchinson-Jeffares' 

PATENT   RAIN   GUTTERS 

For    preventing    rain   washing    away    the    LATEX 

during  the  wet  months  whilst  tapping.  — - 

Claims  : 

'1  liu  only  Gutter  that  cannot  damage  the  Cambium. 

No  more  loss  of  Crops  during  tlie  ^vet  seasons. 

Tappmg  may  be  continued  m  all  weathers. 

Cost  per  acre  to  estabhsh  about  Rs.  5.  Once  up  always  up. 

ilore  profits  to  the  Estate.      More  pay  to  the-  C.jolies.      Gutters  are  expandable. 


Gutters  are  made  in  three  sizes— SMALL,   MEDIUM  &   LARGE. 

For  Paiiictilais  and  Prices,  apply- 

Messrs.  WALKER  Bros.,  Ltd./ COLOMBO. 

The  above  Firm  are  Sole  Agents  in  India,  F.  Malay  States,  and  Ceylon. 


ADVERTISEMENTS  91 


RUBBER  SEEDS^STUMPS 
and  PLANTS. 

Of   the   following  Varieties:  — 

HEVEA    BRASILIENSIS    (Para    Rubber), 

CASTILLO  A    ELASTIC  A   (Panama   Rubber), 

MANIHOT    GLAZIOVII    (Ceara   Rubber), 

LANDOLPHIA   KIRKII    (West  African  Rubber), 

MANIHOT      DICHOTOMA,     M.      PIAUHYENSIS, 

M     HEPTAPHYLLA, 

Can  be  obtained  from 

J.  P.  RICHARD, 

HENARATGODA,    CEYLON. 


Good    Arrival    and    Germination 
guaranteed. 

SEEDS    AND    PLANTS    PACKED    TO    STAND    THE    TRANSIT 
WELL   UP  TO   FOUR   MONTHS   AND  OVER. 


Telegraphic  Address  :  Codes  used  : 

RICHARD,  A.  I,  A.B.C.,  4th  and  5th 

Henaratgoda,  Ceylon.  Ed's.,  and  Liebers. 


92 


A  D  VERTISEMENTS 


THI 


FEDERATED  ENGINEERING  CO.,  LTD., 

LARGEST    MAKERS   IN    THE    EAST   OE 

Rubber  Plantation  Machinery 


4  Views  of  our    Heavy  Pattern    Rubber  Treating  Machines. 

CATALOGUES,    PLANS    AND    PRICES    ON   APPLICATION. 

FACTORIES  SUPPLIED    &    ERECTED   COMPLETE, 

INCLUDING     ENQINLS    AND    ALL    MACHINERY. 


ADVERTISEMENTS  93 


ORDER    NOW    YOUR    COPY    OF 

Rubber  Producing  Companies, 

1912    EDITION, 

IN    PREPARATION. 

This    Valuable    and    Exhaustive   Handbook    gives    full   details 

as   to 

CAPITAL,  SITUATION  OF   PROPERTY, 

FINANCES,  TOTAL  ACREAGE, 

DIVIDENDS  (if  any),     AREA   PLANTED, 

etc.,  etc.,  of 

RIBBER   COMPANIES   \N   ALL 
PARTS  OF  THE  WORLD. 

It   also   includes -a   Directory   of   Directors, 

which  will  form  a  most  valuable  guide  to  the  personnel 

of  new  companies. 

Rubber   Producing  Companies  is  the  most  up-to-date  aud  com- 
prehensive  work  of  reference    of    the   kind   on    the   market,  is 

compiled    by 

Messrs.  GOW,  WILSON   &  STANTON.  Ltd  ,  Tea  and  Rubber 

Produce  and  Share  Brokers,   13  and  23,  Rood  Lane,   London, 

E.G.,    and   THE    FINANCIAL    TIMES,   and  is 

published   by 


72,   COLEMAN   STREET,   LONDON,   E.  C. 

Price     J  S,    Net. 
3s.  id.  post  free  in  United  Kingdom.  Abroad  3s.  6d,  post  jvee. 


94 


AD  VERTISEMENTS 


THE 


Double  Bhckman 

(UNEQUALLED     EFFICIENCY). 

BEST    FOR    DRYING    RUBBER, 
CACAO,  COPRAH,  TEA,  TOBACCO,  TIMBER, 

And  other  TROPICAL  CROPS. 


BLACKMAN   EXPORT  Co-,  Ltd.. 

Cable:  Aculla.  London.  70,  FINSBURY  PAVEMENT, 

Codes :  A  BC  6  W.U.  LONDON,  E.G. 


A  D  VER  TISEMENTS 


95 


^^  ESTABLISHED  1821.  ^ 

SINGAPORE. 

Branches   at    PENANG,       KUALA    LUMPUR, 
PORT  SWETTENHAM    and    LONDON. 

General  l»ercl)ant$, 

Secretaries  &  Agents  to  Rubber  Plantation 
Companies, 

"Bank,   Shipping,   and  Insurance  Agents. 


SOLE   AGENTS 

For    the     Leading     Manufacturers    of 
EQUIPMENT    FOR   RUBBER   ESTATES. 


FRANCIS  SHAW  &  Co.,  Ltd 

Washing  Machines, 
Drying  Stoves, 
Blocking   Presses. 

MARSHALL.  SONS  &  Co.,  Ltd. 

Steam  Engines  &  Boilers, 
Oil  Tractors  for  Hauling 
and  Ploughing. 


NATIONAL    GAS     ENGINE 
Co.,  Ltd. 

Gas  Engines  &  Suction 

Gas  Plants, 
Crude   Oil   and    Petrol 

Engines. 

HAYWARD=TYLER  &  Co.,  Ltd. 

Plunger-Pumps. 


MONO-RAIL  PORTABLE    RAILWAY   Co.,   Ltd. 

Mono-rail    Transport    System. 

FACTORY     BUILDINGS. 


Stocks  of  all  small  Utensils  for  Rubber  Estates  kept  in 

local  Godowns,  also  Poilite  Asbestos  Slates,  Drain  Pipes, 

Expanded  Metal,   Hall's  Distemper,   etc. 


96 


ADVERTISEMENTS 


International 
RUBBER 


AND  Allied  Trades 
EXHIBITION, 

London,  June,  19  14. 


ORGANiaED    BY — 

THE   INTERNATIONAL    RUBBER    AND 

ALLIED   TRADES    EXHIBITION,    LTD., 

A.  STANES  MANDERS,   MailUrr, 

MISS  D.  FULTON,  .'ijci' ;tar>i. 


COTTON 
FIBRE 


AND 

ALLIED    TRADES 

AND 

TROPICAL  PRODUCTS 
EXHIBITION, 


A.     STANES    MANUERS, 

75>    CHANCERY    LANE, 
LONDON.   W.C. 


London, 


1914. 


ADVERTISEMENTS  97 


FOR    EXPORT. 

Para  Rubber  Stumps 

Imported  stumps  saves  the  grower  at  least  one  year's 
time,  and  are  more  reliable  than  seed. 

There  is  only  one  method  of  shipping  stumps  economically. 

My  mode  of  packing  in  closed  cases — a  thousand  occupying 
about  six  cubic  feet  and  weighing  less  then  one  hundred 
pounds — enables  them  to  be  shipped  as  ordinary  merchandise. 

Costs  about  half  the  value  and  gives  equally  good  results 
as  when  Wardian  ca,ses  are  used. 

STUMPS   ARE    GUARANTEED    TO   ARRIVE   AT    LEAST 
75%   SOUND 

The  following  certificate  covers  a  consignment  of  50,000 
stumps  shipped  to  the  Cameroons,  German  West  Africa, 
through  Mr  Stuart  R.  Cope,  (Anti  Tea  Duty  League)  London, 
on  2nd  Sept  1911,  87%  reached  alive  and  in  good  condition 
on  2ist  Nov.  nearly  three  months  after  despatch: — 

"Examined,  Counted,  and  Checked  Twice,  by  Alfred 
"Chandler,  for  and  on  behalf  of  Stuart  R.  Cope,  London, 
"  and  H.  P.  Cavill,  for  and  on  behalf  of  the  Nyong  Rubber 
"Plantations  Ltd.,  acting  under  instructions  from  E. 
"  Luders,  Esq.,  General  Manager.  " 

"Total  Live  and  in  Good  Condition,  43,726." 

"  Signed  in  Duplicate  by  the  said  Alfred  Chandler  and 
"H.  P.  Cavill,  whose  signatures  are  attached,  and  all 
"Live  Plants  taken  to  Dehane  by  Mr.  Cavill  on  21st 
"November  1911. 


One  Year  Old  Selected  Stumps  £3  12s.  per  1,000  fo.b   Colombo, 
and  50,000  and  over  at  £3  7s.  6d.  per  1,000  f.o.b. 

Delivery  two  weeks  after  receipt  of  order. 

At  least  half  value  must  accompany  order,  balance   to    be 
paid  on  delivery  at  destination. 


A.  VAN  STARREX,  F.R.H.S., 

Crystal  Hilt  Estate,  MATALE,  Ceylon. 

Code:  A  B.C.    5th  Edition.  Telegraphic  Address  :      Starrex,  Matale. 

Write  for  Price  List  of  Seeds  and  Plants  of  Tropical 
Products,  Green  Manuring  Plants,  Shafie  Trees,  etc. 


ADVERTISEMENTS 


JUST    PUBLISHED. 

THE 

9th    EDITION 

OF 


mtitr 

RUBBER    SHARE 
HANDBOOK 

(Illustrate). 


The  book  contains  all  the  latest 
information  of  Sterling,  Rupee,  and 
Dollar   Rubber  Companies. 


T'rice    u.    6d. 

Offices  : 

54,  WOOL  EXCHANGE. 

LONDON.  EC. 


ADVERTISEMENTS  gg 


THE 

RUBBER  ESTATE  HGENCY, 

LIMITED, 

MINCING  LANE  HOISE,  59,  EASTCHEAP, 
LONDON,  EX. 

SECRETARIES    TO  : 

The  Eastern  International  Rubber  and  Produce  Trust,  Ltd. 
The  British  and  Continental  Tea  Plantations  Trust,  Ltd. 
The  Anglo-Dutch  Estates  Agency,  Ltd. 
The  Java  Rubber  Plantations,  Ltd. 
The  Langkat-Sumatra  Rubber  Co.,  Ltd. 

COMMERCIAL  AGENTS    and    SECRETARIES   TO  :— 

The  Bandar-Sumatra  Rubber  Co.,  Ltd. 

The  Serdang  Central  Plantations,.  Ltd. 

The  P'rye  Rubber  and  Coconut  Plantations,  Ltd. 

The  Lavant  Rubber  and  Tea  Co.,  Ltd. 

The  Java  Amalgamated  Rubber  Estates,  Ltd. 

The  Eastern-Sumatra  Rubber  Estates,  Ltd. 

The  Tamiang  Rubber  Estates,  Ltd. 

The  Sempah  Rubber  Estates,  Ltd. 

The  Batu  Kawan  Rubber  and  Coconut  Plantations,  Ltd. 

The  Jeram  Rubber  Estates,  Ltd. 

The  Soemberajoe  Rubber  Estates,  Ltd. 

The  Glen  Bervie  Rubber  Co.,  Ltd. 

The  Alluta  Rubber  and  Produce  Co.,  Ltd. 

The  Upolu  Rubber  and  Cocoa  Estates,  Ltd. 

The  Bantardawa  Rubber  Estates,  Ltd. 

The  Indian  Peninsular  Rubber  and  Tea  Estates,  Ltd. 

The  Sungei  Bahru  Rubber  Estates,   Ltd. 

The  Medini  Maatschappy. 

yHE   RUBBER   ESTATE  AGENCY,  LTD.,   is  prepared  to 
negotiate   for   the   purchase   of   Rubber,    Tea,    and   other 
iEstates  in  the  Middle  East,  and  the  formation  of   Public   or 
Private  Companies  to  carry  on  same. 

The  Agency  undertakes  the  conversion  of  Dollar  and  Rupee 
into  Sterling  Companies  under  the  Companies  Acts,  and  the 
provision  of  additional  working  Capital. 

Principals  or  their  Solicitors  only  dealt  with. 

Correspondence  invited. 

AGENCIES  AND  CORRESPONDENTS  IN  ALL  EASTERN  CENTRES. 

Telegraphic  A,ddress- — ■" Aiders,  London."        Telephone: — 11473   Central. 
Codes: — A. B.C.,  5th  Edition,  Mercuut,  Broomhall,  BentUy. 


OC 


ADVERTISEMENTS 


ASSOCIATION  PES  PLANTEURS  DE 
CAOUTCHOUC- 

(Rubber  Growers'  Association). 


'"PHIS  Association  has  been  formed  to  promote, 
combine  and  defend  the  interests  of  the 
Rubber  Planters  in  the  world.  It  has  an  inter- 
national character,  and  is  in  close  touch  with  the 
English  Rubber  Growers'  Association  in  London, 
and  the  Planters'  Community  in  Central  America, 
Central  Africa  and  the  East. 

It  publishes  a  monthly  bulletin,  which  is  an 
agricutural,  technical,  commercial  and  financial 
paper,  the  only  review  in  French  devoted  to  the 
practical  study  of  the  Rubber  Planting  Industry. 

Published  at  middle  of  every  month.  Annual 
Subscription— 12/- 

This  handsome  review  contains  every  month 
articles,  especially  written  for  the  Association  by 
the  leading  Rubber  Planters  in  all  countries;  it 
closely  follows  the  technical  and  financial  develop- 
ment of  Rubber  Plantations  in  the  tropical  world, 
and  offers  the  best  suited  field  for  advertising  new 
methods  and  machines  connected  with  the  Rubber 
Planting  Industry. 

Write  for  information  to  the  Secretary. 
HEAD   OFFICE:— 

48  Place  de  Meir,  Antwerp  (Belgium) 


ADVERTISEMENTS 


LIIVIITED. 

London  Office  :  Offices  in  the  East  : 

Mincing  Lane  House,  Medan  &  Tebing  Tinggi  (Sumatra), 

59,' Eastcheap,   E.C.  Sourabaya  (Java). 


T'HE  AGENCY  undertakes  the  Management,  Supervision,  and 
Visiting  Agency  of  Estates  in  Sumatra  and  Java,  and  keeps 
its  own  Accountancy    Staff,  who  examine  all  Accounts  before 
forwarding  to  London. 

The  Agency  also  undertakes  provision  of  Estate  supplies, 
local  Sales  of  Produce,  etc.,  and,  in  addition,  is  favourably 
situated  for  the  supply  of  Machinery  and  Factories,  having 
entered  into  agreements  with  Manufacturers  by  means  of  which 
it  is  able  to  offer  special  terms  to  Clients. 

Commercial  or  Visiting  Agents  jor 

The  Bandar  Sumatra  Rubber  Co.,  Ltd. 

The  Deli  Padang  Maatschappij . 

The  Eastern  Sumatra  Rubber  Estates,  Ltd. 

The  Glen  Bervie  Rubber  Co.,  Ltd. 

The  Java  Amalgamated  Rubber  Estates,  Ltd. 

The  Java  Rubber  Plantations,  Ltd. 

The  Langkat  Sumatra  Rubber  Co.,  Ltd. 

The  Lankat  Rubber  Co.,  Ltd. 

The  Nederlandsch-Indisch  Land  Syndicaat. 

The  Poelahan  Rubber  Maatschappij. 

The  Serdang  Central  Plantations,  Ltd. 

The  Soember  Ajoe  Rubber  Estates,  Ltd. 

The  Sumatra  Plantage  Maatschappij. 

The  Tamiang  Rubber  Estates,  Ltd. 

Messrs.  Van  Heekeren  &  Co.,  Amsterdam. 

The  Amsterdam  Londen  Verzekering  Maatschappij. 

The  Insulinde  Cultuur  Syndicaat. 

The  Agency  is  open  to  accept  Agencies  for  Machinery  and 
Estate  Goods,  Agricultural  Implements,  etc.,  and  General 
Merchandise. 


Correspondence   Invited. 

Telephone: — 11473  Central.  Telegrams: — '-Anduesta,"  London. 

Codes : — A  B  C  (5th  Edition),  Mercuur,  Broomhall,  Bentley. 


ADVERTISEMENTS 


PATENT 


Ventilated  :  Rubber :  Box. 


Ventilation  tHT 
perforations  extend 
along  the  four  cor- 
ners. 


This  box  is  ventilated  at  all  four  corners,  and  is  constructed 
without  corner-pieces  or  internal  fittings  of  any  kind,  so  that  the 
contents  may  be  conveniently  discharged.  It  weighs  lalbs.  and 
holds  i3olbs.  Rubber  ;  the  gross  weight  is  therefore  not  too  great 
for  easy  handling.  It  can  be  supplied  with  less  or  more  venti- 
lation perforations  than  shown  in  illustration,  or,  if  preferred, 
they  can  be  altogether  omitted. 

PRICE: 

2s.  6d.,  each  c.i.f.  Calcutta,  Colombo  or  Batavia — packed  in 

cases  of  10  boxes. 

QUOTATION     FOR     OTHER     SIZES     ON     APPLICATION 

TERMS  :  Cash  against  Shipping  Documents.     DISCOUNTS :  according 

to  Quantity. 


The  ACME  TEA   CHEST  CO.. 

LIMITED, 

Patentees  and  Manufacturers  of  Packages  for  Tea,  Rubber,  &c., 

TeUgrams:  GLASGOW,  ABC   Code, 

"Chests,"  Glasgow.  SCOTLAND.  5th  Edition. 

/'.  HTUART  BROWN,  Mnna^iuy    Dhv.-lor 
TIMBER     FdRESTS:  '     '  LONDON: 

Cape  Fear  River,  Impkrial  Tea  Chests  Ai;kncv,  Ltd., 

;AR0L1NA,   U..S.A.  4  LLOYDS  AVENUE. 

CEYLON : 

THE     r.ALAIIA     CEYLON     TEA    ESTATES     AND     AGENCY     CO.,     LTD., 

COLOMBO 
JAVA  . 

BOMBAY     J.4VA    TRADING     COMPANY,     LTD.. 

BATAVIA, 


NORTH  CAROLINA,   U..S.A. 


ADVERTISEMENTS 


103 


THE  GLASGOW  STEEL 
ROOFING  Co7,  Ltd. 

Nortli.  'Western   TATorlcs, 


h-rih-ij--rihff-i^--  -4-dr-m 


^i        ^: 


I; 


:<q^ 


r 


Approved  Design  Steel  Framed  Coolie  House. 


Cables:    "ROOFING,    GLASGOW." 


I04  ADVERTISEMENTS 


THE    RUBBER    TRABE    LIBRARY. 

"RUBBER  "  by  Philip  Schidrowitz.     300  pp.  Svo.     Covers  in  a  thoroughly  practical  and  critical 
manner  the  different  branches  of  the  rubber  industry.     Up-to-date.     Price  los.  6a.     Post  free  its. 

"RUBBER  AND  RUBBER    TEA  AND  COCOA  ESTATE  REPORT  SHEETS  AND  BOOKS."— 
Specimen  and  Prices  on  appUcation.  * 

"LOSS  ON  WASHING  TABLES  "  showmg  the  exact  cost  of  Rubber  at  aU  prices  from  is.  to  4s.  ii}d. 
after  deducting  the  loss  on  washing  and  drying  at  the  difierent  percentages  from  i  to  60  per  cent. 
Indispensable  to  the  Costing  Clerk.     Mounted  on  cards  and  cloth  bound  for  handy  reference. 
Price  7s.  6d. 

"CULTIVATION     AND     PREPARATION     OF     PARA     RUBBER."— By  W.  H.  Johnson.     2nd 
Edition.     Price  7s.  lod.,  post  free. 

"INDIA-RUBBER   AND  GUTTA-PERCHA."— By  T.  SeeUgman.     Large  Svo.     Price  12s.   rod. 
post  free,  13s.  6d.  foreign.    A  complete  practical  treatise  on  India  Rubber  and  Gutta-Percha. 

"HEVEA  CULTIVATION:    A  HANDBOOK  FOR  THE  PLANTER."— By  Dr.  Cramer.     136  pp., 
large  Svo,  in  English,  Dutch,  and  French  Editions.    Cloth  bound.    5s.  3d.,  post  free. 

"TAPPING     METHODS."— By  Prof.  Fitting.    English  Translation,     is.  id.,  post  free. 

"HOW    TO    JUDGE    RUBBER    INVESTMENTS."— By  Frederick  W.  Knocker,  F.2.S.,  F.R.A.I. 
2S.  gd.  post  free. 

"THE  MANUFACTURE  OF  RUBBER  GOODS.  '—By  Adolf  Heil  and  Dr.  W.  Esch.     Price  ios.6d. 
net ;    post  free  los.  rod. 

"RUBBER    AND    RUBBER    TESTING."— Hinrichsen  and  Memmler.     Cloth  bound  (in  Gennan). 
gs.  6d.,  post  free. 

"THE     PHYSIOLOGY     AND     DISEASES    OF    HEVEA-BRASILIENSIS."— By  T.  Fetch,  B.Sc, 
B.A.     Price  Ss.,  post  free. 

"CRUDE     RUBBER    AND    COMPOUNDING     INGREDIENTS."— By  H.  Pearson.    A  work  for 
Manufacturers.     Price  £2  net.    Second  Edition  Now  Ready. 

"RUBBER  TYRES  AND  ALL  ABOUT  THEM."— By  Henry  C.  Pearson  (U.S.A.).     Price  12s.  lod. 
post  free. 

"UNIVERSAL  GRADING  OF  SCRAP  RUBBER."— Bv  A.  W.  Leslie.     Price  2S.  8d.  post  free. 

"RUBBER     CULTIVATION     IN     THE     BRITISH     EMPIRE."— By  Herbert  Wright,  A.R.C.S., 
F.L.S.     Price  2S.  Sd.  post  free. 

"PARA   INDIA  RUBBER."— By  H.  A.  Wickham.     Cloth.     Price  3s.  gd.,  post  free. 

"INDIA-RUBBER    AND    ITS    MANUFACTURE."— By  H.  L.  Terry,  F.l.C.    About  300  pages. 
Borjid  Cloth.     Price  6s.  3d.,  post  free. 

MATHIEU'S   "PARA   RUBBER   CULTIVATION."— Text  in  French  and  English.     Price  15s.  4d., 
post  free. 

"RUBBER"   (PITMAN'S  SERIES).— By  Clayton  Beadle  and  Stevens.     Price  is,  8d.,  post  free. 

"RUBBER  COUNTRY  OF  THE  AMAZON."— By  H.  C.  Pearson.     Price  13s.,  po-t  free. 


WRITE     FOR     OUR     CATALOGUE     OF     RUBBER     BOOKS. 

All  other  Trade  Works  can  he  obtained.        Terms — Cash  With  Order.       Address — 

Book  Dept.,  INDIA-RUBBER  JOURNAL,  37-38  Shoe  Lane,  London,  E.C 


Socictc    OoioAiak    ^nymoise, 

Antwerp  Offices  :  15,  RUE  RUBENS.     Telephones  378  &  653. 

Crude  Rubber  Importers  S  Dealers, 


India  Rubber   Merchants. 


•  ■       ■■ 
■  •       ■■ 


Speciality:  PLANTATION  RUBBER 


Crude  Rubber  Consignments  Solicited. 


ADVERTISEMENTS  105  oaj 


BY    ROYAL      7^m^       WARRANT. 


FISONS' 

FERTILIZERS. 

"THE     BEST     IN     THE     WORLD." 

—    FOR   — 

RUBBER^  TEA,  COFFEE,  SUGAR,  Etc. 

Write  for  full  particulars  of  fertilizers  for  tliese  and 

otfier  crops.     Tfic   quality  is  high,  price  moderate, 

and  conditions  perfect.      Fisons'  Fertilizers  are 

used  all  over  the  World. 

THE  CHEMICAL   UNION,  Ltd,  IPSWICH,  ENG. 


Ease,    Safety,    Simplicity, 

Are  the  Characteristics  of  the 

Cater-Schofield 

TAPPING  KNIFE, 

Suitable  for  any  system  of  Tapping,  and  can  be  regulated 
for  any  depth  of  incision— 


HEVEA,  FICUS,  GEARA,  or  CASTILLOA. 


Send  for    Descriptive   Circular   and 
Prices 


Skelton  &  Schofield, 

29,   MARTIN'S   LANE,   CANNON    ST., 
—  LONDON,  EC  — 


io6 


ADVERTISEMENTS 


eOMBIMED-MESH 


WIRE/NETTine. 


ETC.  '-^^3 


eO/MTINUOU5  •  BAR  FErtCI/SS  0 


f^.. 


W.  I.  UNGLIMBABLB 
r  I  I  I  I  I  I  I  I  I  I  I  I  I 


/t^  RAILI/NG. 


i 


Ifflffi.- 


TREE    GUARDS. 


BAYLISS.J0I1G 


mam 


FENCINCGATESs. 


CORRUGATED 
-^  SHEETS/ 

-     -  m\ 


SHEEP  HURDLES    ETC 


/ 


:^g^gg'^  WOLVERHAMPTON^  "l^S^:!  S 


Please  Mention  This  Book. 


TO     RUBBER     PLANTERS 
AND     OTHERS. 


f— ♦— i 

Specialities  for  the  destruction  of 

LALANQ    QRASS,    SCRUB,    &c.,     LOCUSTS, 
WHITE  ANTS,  &c.,  FUNGOID  DISEASES,  &c. 

IVIanufacturers  of 

ARSENATE   OF   LEAD,   Paste  or  Powder, 

For  the  destruction  of  all  leaf-eating  insects. 

ARSENITE    OF    SODA,    60%,    68%,    70% 
FERTILIZERS. 

ENQUIRIES    INVITED.         QUOTATIONS    AT    LOWEST    EXPORT    PRICES. 


ACME    CHEMICAL   CO.,   Ltd., 

TONBRIDGE,   KENT,   and  River   Street,   Bolton, 

^Lancashire,   England. 

Contractors  to  the  Crown  Agents,  India  Offlce,  etc 


ADVERTISEMENTS  107 

Fob  Rubber  Plahters. 

Lactic  Acid, 

A   harmless  highly  antiseptic  coagulent. 


y         Lactic  Acid  has  the  advantage    against  other  organic 
acids  that  it  is  not  evaporating. 

The  following  is  the  report  of  a  well  known  chemist : — 
"A  5%  solution  of  Acetic  Acid  destroys  all  germs  and  it  acts 
"  more  favourably  than  other  disinfectants  as  its  action  is  not 
"  corrosive.  It  can  be  specially  recommended  in  cases  where 
"  tender  tissue  has  to  be  protected  against  fermentation." 

For  further  particulars  please  apply  to 

CH.    &    A.    BOHRINGER, 
COLOMBO. 


WILLIA[\/I&  RICHARD. 

Florists,  Seedsmen,  and  Plant  Merchants, 

ALEXANDRA     GARDENS, 

HORTON  PLACE.  COLOMBO.  CEYLON. 


TROPICAL  SEEDS  &  PLANTS  OF  COMMERCIAL  PRODUCTS 
A  SPECIALTY. 


►      PARA,  CASTILLOA,  CEARA,  TEA.  COFFEE,  COCOA, 

CARDAMOM,  VANILLA,  PEPPER,  KOLA,  SPICES,  &c. 

ORNAMENTAL,    FOLIAGE,    SHADE,  TIMBER,    &    FRUIT 

TREES,  &c.,  &c., 

FORWARDED  TO   ALL  PARTS  OF  THE  WORLD. 


Telegraphic  Address  :  "Bouquet,  Colombo." 
Code  Used :    Ai,  A.B.C.,  4th  and  5th  Editions. 


io8 


ADVERTISEMENTS 


IVIanuring  for  Rubber  Trees. 

Experiments  show  that  lor  Rubber  Treei  as  well  as  tor  other 
Tropical  and  Sub-Tropical  Plants 

POTASH 

Should     b^    Iricluded 
IN    EVERY    WELL-BALANCED     COMPLETE     FERTILIZER, 

IN     ORDER     TO     GAIN 

Higher  Yields,  Better  QufliiTY,  Larger  Profits. 

POTASH     MANURES    CAN     BE     SUPPLIED     AS  :— 


MURIATE  of  POTASH 


KAINIT 


SULPHATE  of  POTASH 


or     INDIA     RUBBER,    TEA,  for  COTTON  and  I    for  TOBACCO,  SUGAR  CANE, 

COFFEE,   COCOA  &  RICE.       !  COCO-NUTS  i    PINEAPPLES  &  FRUIT  TREES 

Information  {iven  and  Pamp'hiets  sent  FREE  on  APPLICATION  to: — 

KALISYNDIKAT,   G.mB.H.,    BERLIN,  S.W.,  11. 

DESSAUER  STRASSE,  28,   29. 


BEp,  MEYER  &  Co.,  Ltd.,  SlMGAPQIjE, 

And  at  Penang,  Sandakan,  Bangkok,  Batavia,  Soerabaya, 
Telok    Betong,     Manila,     Ilo    Ilo,     Cebu,    Zamboanga. 

HOME     OFFICES- 
ARNOLD    OTTO    MEYER,    1,    Alsterdamm,  Hamburg. 
ARNOLD  OTTO  MEYER  &  CO.,  39,  Mincing  Lane.  London. 

ESTATE  DEPARTMENT 

acts  as  Managing  and  Commercial  Agent  for 
Home  and  Eastern  Rubber  and  Produce 
Companies. 

MANURE   DEPARTMENT 


has  wide  experience  in  the  selection  and  use  ot 
manures  lor  all  conditions  of  soil  and  always 
carries  large  stock  of  all   classes  of  manure. 

ENGINEERING  DEPARTMENT 

supplies  complete  installations  of  Rubber 
Factories  and  every  kind  of  Estate  implements. 


ADVERTISEMENTS  109 


RUBBER  CURING 


Prevents 

tackiness,  ^^^^^^— ^^^^—  Suitable 

and  for 

BY     MEANS    OF  ^^^moked 

uniformity,  *•■■*••••••••  pale  or 

r"  ™E  giRoccQ  MUK.  - 

and  ^— — — — —  brown 

even  Rubber. 


colour. 


Apparatus 


DAVIDSON  &  CO..  Ltd., 

Sirocco  Engineering  Works,  BELFAST. 

"SO- WO" 

SOLID    WOVEN     GOTTON 
BELTING. 

"  INEXPENSl  VE     A  ND     LA  STING." 

A  SPECIAL  WEAVE  MADE  &  PREPARED 

EXPRESSLY    FOR    USE     IN    TROPICAL 

COUNTRIES,   WHERE   EXTREME    HEAT 

AND    DAMPNESS   PREVAIL 

Full  Particulars  from 

y.  RDBERTSOII  s  Co.,  68,  Gordon  St,  GLASGOW 

London  Office :  John  O.  Fitch,  133,  Fenchurch  St.,  E,C. 


ADVERTISEMENTS 


OHLENDORFF'S 
FERTILIZERS 


-:  FOR  :— 


RUBBER,     TEA, 

TOBACCO,     COFFEE, 

COCOA,    Etc., 

Also  BASIC  SLAG,  SUPERPHOSPHATES,  etc. 

BUYERS-     OWN     PRESCRIPTIONS     PREPARED. 

ANGLO -CONTINENTAL    GUANO     WORKS 

(Late   OHLENDORFF'S), 

Dock    House,     Billitep    Street,    London,    E.G. 


SEED     PLANTS 

FORWARDED     TO 
ALL     PARTS     OF    THE    WORLD. 


COFFEE, 

TEA, 

COCOA, 

RUBBER, 

CINNAMON, 

CARDAMOM, 

PEPPER, 

CINCHONA, 

COCA, 

COLA, 

CLOVE, 

NUTMEG, 

COTTON, 

CROTOLARIA, 


ALL     KINDS     OF 


VIGNA, 

GROUND  NUTS, 
GREVILLEA 
ALBIZZIA, 

Etc.,  Etc, 
OF  Fruit  Trfes 
MANGO, 
DURIAN, 
MANGOSTEEN, 
SAPODILLA, 
Avocado  Pear. 


LITCHI, 
RAMBOOTANS, 
LOQUAT, 
ORANGE, 
LIME, 
LEMON, 
Custard   Apple. 
ALMONDS, 
JAMBOS, 
PAPAYA, 
GRAN.ADILLA, 
Etc  ,  Etc. 


PALMS, 
FERNS, 
CYCADS, 
ORCHIDS, 
LILLIES, 
CROTONS, 
HIBISCUS 
ANTHURIUMS, 
MAR.AXTAS. 
Etc,    Etc. 


PRICE     LIST     ON     APPLICATION. 


J.  P.  ABRAHAM,  ^""^srrM:"!.. 

MUTWAL,     COLOMBO,     CEYLON. 


ADVERTISEMENTS 


COMPOSITE    IRON 

AND 

WOOD   BUILDINGS 

INEXPENSIVE    AND    EFFICIENT. 

( BUfsr  G.a.iL.0  w  s) 

Specially  designed  and  conatmcted  for  use  in  the 

tropic-. 

(Mosquito  and  aut  proof  if  required.) 

COOLIE    LINES,  FACTORIES,  STORES,  ETC, 

STEEL  ROOFS  AND  LIGHT  BRIDGES. 

OUR  WORKS  are  the  largest  and  best  equipped  in 
this  countiy,  and  beiu^  situated  adjoining  the  prin- 
cipal docks,  we  are  In  a  position  to  quote  very 
favourably. 

All  Buildings  for  expo  t  are  erected  complete  before 
despatch  and  can  be  easily  erected  at  site  by  native 
workmen. 

DESIGNS     AND     COMPLETE     ESTIMATES     SUBMITTED     FREE     OF     COST. 

li^.    I>.    COIK^IESON  <Sc     Co., 

DESIGNERS,   STRUCTURAL    ENGINEERS    AND    PATENTEES, 

Building  Dept.,  4  to  44,  Charles  Street,  St.  Rollox,  Glasgow,  Scotland 

X  B.— When  sending'  enquiry     please  give  a**   many    particulars    as    porfsibl*.    this    to 
%  save  delay  and  disappointment. 


H.   BRINDLEY, 

ESTABLISHED     1828, 

298,  SIMMER  LANE,  BIRMINGHAM. 

MAKER    OF 

TAPPING     KNIVES 

OF    DIFFERENT    DESIGNS. 

My  Rubber  Tappers  are  renowned  for  their 
simplicity  of  construction  and  ensure  easy  and 
safe  Tapping  of  all  kind  of  Rubber   Trees. 

!'      THEY  ARE  A  BOON  TO  EVERY  PLANTER. 


ADVERTISEMENTS 


NIEUW  PRAAUWENVEER 


(LIGHTER    COMPANY), 

SOURABAYA,  (JAVA.) 


Teltgraphie  Address : 

KojANG,  Sourabaya. 


Past  Address : 


NiEUw  pRAAuwENVEER,  Sourabaya. 


Transport  of  all  kinds  of  Produce,  Merchandise  and 
Machinery  from  ships  in  the  roads  to  the  Sourabaya 
Harbour,  quays,  or  vice-versa. 


STROOHOEDENVEEM, 


SOURABAYA   (JAVA). 


Telegraphic  Address: 

Stroohoed,  Sourabaya. 


Post  Address: 


Stroohoedenveem,  Sourabaya. 


Acts  as  Custodian.  Issues  Warrants. 

Clearing  and  forwarding  to  the  Interior  of  Merchandise. 


ADVERTISEMENTS 


113 


THOMAS'  PHOSPHATE  POWDER 

(BASIC   SLAG) 

(Albert's  and  Star  Brand). 
CHEAPEST    AND    BEST    PHOSPHATIC    MANURE 

— ■      FOR       ■ — : 

RUBBER,    SUGAR    CANE, 

TEA,    CACAO,    COFFEE, 

And  all  other  Crops. 


Largely  increases  YIELD  and  Improves  QUALITY. 


PLEASE  APPLY  FOR  PARTICULARS  : 


United  Thomas'  Phosphate  Works, 

15,  PHILPOT  LANE,  LONDON,  EC. 


SCHOPPER'S  RUBBER  TESTER 


PATENTED. 


For  ascertaining  the  strength 
and  elasticity  with  accuracy. 
A  new  metliod,  satisfying  the 
most     exacting     requiremenls. 

Thickness  Gauges 
All  Precision  Appliances 

for  testing  web  fabrics,  yarns, 
etc.  Analytical  and  Precision 
Balances 

LOUIS     SCHOPPER, 

kEIRZIG,     GERn/IANY. 


Sole  Agents  in  Great  Britain : 

JOHN  J.  GRIFFIN   S   SONS,  Ltd., 
Kingsway,  London. 


114  ADVERTISEMENTS 


SHIP     YOUR     RUBBER     IN 

''VENESTA"  CASES 


"VENESTA"  RUBBER  CASES  are  smooth  inside  and 
there  is  no  risk  of  splinters  sticking  in  the  rubber,  as  is 
the  case  with  rough  sawn  cases. 

"VENESTA"  CASES  turn  out  the  rubber,  with  the 
minimum  of  oxidation,  which  means  from  2d.  to  6d.  per 
lb.  better  price  obtained. 

"VENESTA"  RUBBER  CASES  are  made  of  ply-wood 
throughout  and  therefore  possess  extreme  lightness, 
with  no  loss  of  strength,  and  save  about  10  %  of  the 
IMPORT  FREIGHT  on  Rubber,  and  about  15%  of 
RAIL  TRANSPORT  on  tbe  packed  cases. 


VENESTA,  Ltd.,  1  Great  Tower  St.,  London,  e.c. 


The  Leading  House  for   TAPPING  KNIVES.    ""iZll''" 

"Java."     "Para."     "Malay."      "  Jebongs." 
"Secure."  "Ceylon."  "  Ren  gam."  etc.,  etc. 

TREE    MEASURING    CALLIPERS 

-     -     and    "Sumatra"   GOUGES. 


Hanufaeturedl>y   JHOS.   NEWEY  &  SONS, 

Central  Gool  Otorks,  BIRMINGHHM. 

—     ESTABLISHED     1740.     — 


London    Office— 3.    CROSS    LANE,    EASTCHEAP,     E.C. 


ADVERTISEMENTS 


115 


DYNAMOM 

PATENT  APPLIED  FOR  IN  ALL  COUNTRIES. 


R 


Trade  Mark  :  P.B. 


HIGHEST    PRECISION. 

For  testing  supple  and  hard  Rubber,  Ebonite,  Celluloid,  Linoleun,  Wax-elotli, 
Cables,  Tlireads,  Textile   Fabrics,  Belting,  Plastic  Materials,  etc.,  etc., 

THE     OITLT    DYITAMOMETEB    IN    THE    WORLD. 

FOR    THE    TESTING    BY 

TENSION    (slow,  sudden  or  alternate). 

COMPRESSION   (slow,   sudden  or  alternate). 

FLEXION   (slow,  sudden,  or  repeated  bending). 

WEAR  AND  TEAR   (determination  of  the  coefficient  of  friction). 

PLASTICITY,  etc.,  etc. 

It  can  be  used  for  testing  at  any  temperature.     It  traces  automatically  diagrams. 
It  can  always  be  verified  by  tlie  operator  himself. 


A.     D.     ClkkARD, 

Mechanical  Engineer,  Government 
49,    RUE    DES    VINAIGRIERS, 
Branches, 

Marseilles    . .   29,  Rue  Pavilion 

Hamburg  21 . .  43,  Osterbeckstrasse 
New  York     . .  43-45.  West  34th  St. 
Johannesburg  Palace  Buildings 
Obidos  (Bresil). 
Majunga  (Madagascar). 


(  CORRESPONDENTS : 

CONSTANTINOPLE.  MADRID. 

BRUXELLES.  CEYLON. 


SINGAPORE. 

GRAND    PRIX  : 


international 


Contractor,       EE)  ?J  § 
PARIS. 

Awards. 
Bordeaux  1907      i  Gold  Medal 
NoGENT  1907  I     „         „ 

Paris  EXP,  sp.  1907  I  „ 
Toulouse  igo8  i  ,, 
Franco.  BRIT.  1908  I     ,, 

secretaire  cl.  99 
Marseille  1909      i     ,, 
Bruxelles  1910 


Prix 


Francfort  1 910 
Bruxelles  1910 
Buenos-ayres 
DoUAi  Tgio 


2  Grand 

(Col.) 
Hors  Concours 
2  Gold  Medals 
I     ..         ,, 
I  Diploma 

d'Honneur 


Clermont-  Ferr 

1910  1 

Exhibition,    Brussels,    1911, 


Sole  Agents  for  the  United  Kingdom- 

W.  MARTIN  &  CO., 


93,  Aldersgate  Street,  London,  E.C. 


ff 


Il6 


A  D  VER  TISEMENTS 


Le  Caoutchouc  & 
La  Gutta-Percha. 


Scientific  &  Industrial  Record  of  the  Raw  &  Manu- 
factured Rubber  &  Outta°Percha  &  Allied  Industries. 

The  Review  is  independent  of  any  Financial  or  Cotnmer-cial  groups 

Director :    A.    D.    CILLARD,     is  u  j     Engineer. 

Commercial  Councillor  for  Foreign  Countries. 

PARIS  :  i9,  Rue  des  Vinaigriers,  Paris  (Xe). 


Sole  Representatives  for  U.K. :  W.  MARTIN  &.  Go.^ 
93,  Aldersgate  Street,    London,   E.G. 


AWARDS  : 


Bordeaux   1907 

1  Gold  Medal 

Nog-ent  1907 

1       „ 

Paris  Exp.  Sp. 

1907 

1        , 

Toulouse  igo8 

1       ., 

Franco-Britque 

1908  Secretaire  cl 

1 

Marseilles  1909 

1                M 

Brussels  igio 

2  Grand  PHm 

Brussels  1910 

2  Gold  Medals 

Douai  1910 

Clermont-Ferrd 

1910 

1             „ 

Francfort  1910 

Hors  Concours 

Vice-President  of  the  London  Rubber  &  Allied  Trades  Exhibitions  of  1908  &  I9lt 

BRANCHES : 
MARSEILLES : 


29   rue  Pavilion. 

HAMBURG  21  : 

43  Osterbeckstrasse. 

NEW    YORK: 

43-45  West  34th  Street. 


JOHANNESBURG : 
Palace    Building. 

OBIDOS    (BRESIL). 

MAJUNGA  (MADAGASCAR). 


CORRESPONDENTS : 
Constantinople.  Madrid.  Brussels.         Ceylon.  Singapore. 

GRAND  PRIX  :  Brussels  International  Exhibition,    1910. 

Telegraphic  Address :  DRALLIC,  PARIS.    Codes  used :  Western  Union ;  A.B.C.,  5th  Edition. 


ADVERTISEMENTS  117 


Im  Verlage  des 

Kolonial-Wirtschaftlichen  Komitees 

Berlin  NW7,  Unter  den  Linden  43 

erscheinen  fortlaufend  : 

Der  Tropenpflanzer,  Zeitschrift  fiir  tropische  Landwirtschaft  mit  wissen- 
schaftlichen  und  praktischen  Beiheften,  monatlich.  1912.  XVI. 
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Ungarn  und  die  deutschen  Kolonien,  M.  15, —  fiir  das  Ausland. 

Kolonial-HandelS-AllreBbuch,\i5.  Jahrgang,  Ausgabe  1911.     Preis  M.  2,50. 

Berichte  Uber  Deuisch-koloniale  Baumwoll-Unternehmungen  : 
Baumwoll-Expedition  nach  Togo  1900.    (Vergrifien.) 
Deutsch-koloniale  Baumwoll-Unternehmungen.    Bericht  I — XV,  Karl 
Supf. 

Verhandlungen  des  Vorstandes  des  Kolonial-Wirtschaftlichen  Komitees. 

Verhandlungen  der  Baumwollbau-Kommission. 

Verhandlungen  der  Kolonial-Technischen  Komission. 

Verhandlungen  der  Kautschuk-Kommission. 

Sonstige   Veroffentlichungen 
des    Kolonial-Wirtschaftlichen    Komitees : 

Wirtschafts-Ailas  der  Deutschen  Kolonien.    Zweite,  verb.  Aufl.  Preis  M.  5,—. 
Kunene-Zambesi-Expedition,  H.  Baum.    Preis  M.  7,30. 
Samoa-Erkundung,  Geh.  Reg.-Rat  Prof.  Dr.  Wohltmann.     Preis  M.  2,25. 
FiSChflUSS-Expedition,  Ingenieur  Alexander  Kuhn.     Preis  M.  2, — . 
Wirtschaftliche  Eisenbahn-Erkundungen  im  mittleren  und  nordlichen  Deutsch- 

Ostafrika,  Paul  Fuchs.     Preis  M.  4, — . 
Die  Wirtschaftliche  Erkundung  einer  ostafrikanischen  Sudbahn,  Paul  Fuchs. 

Preis  M.  3, — . 
Die  Baumwollfrage,  ein  weltwirtschaftliclies  Problem,  Prof.  Dr.  Helfierich, 

Wirkl.  Legationsrat  a.  D.     Preis  M.  i , — . 
Die  wirtschaftliche  Bedeutung  der  Baumwolle  auf  dem  Weltmarkte,  Eberhard 

von  Schkopp,  Preis  M.  1,50. 
Die  Baumwolle  in  den  Vereinigten  Staaten  von  Nordamerika,  Moritz  Schanz. 

Preis  M.  1,50. 
Plantagenkulturen  auf  Samoa,  Prof.  Dr.  PreuB.    Preis  M.  1,50. 
Deutsche  Kolonial-Baumwolle,  Berichte  1900-1908,  Karl  Supf,  Preis  M.  4, — . 
Unsere  Kolonialwirtschaft  in  ihrer  Bedeutung  fur  Industrie,   Handel  und 

Landwirtschaft,  Preis  M.  1,50. 
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rung  an  deutsche  Prospektoren  zur  Betatigung  in  unsern  Kolonien. 

Pr.  75  Pf. 
Neue      Maschinenindustriezweige,      Deutsche       Baumwoll-Emtebereitungs- 

maschinen,  Deutsche  Palrnol  -  und  Palmkem  -  Gewinnungsmaschinen, 

Karl  Supf,  Preis  M.  1,50.     (Vergriffen.) 
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Zimmermann.     Preis  M.  2, — . 
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Dr.  Zimmermann.     Preis  M.  i, — . 
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Die  Guttapercha-  und  Kautschuk-Expedition  des  Kolonial-Wirtschaftlichen 

Komitees  nach  Kaiser  Wilhelmsland  1907-1909,  von  Dr.  R.  Schlechter. 

Preis  M.  5, — . 

samtlich  zu  beziehen  durch  die  Geschaftsstelle  des 
Kolonial-Wirtschaftlichen  Komitees,  Berlin  NW7,  Unter  den  Linden  43. 


ii8  Advertisements 


The  India -Rubber  World. 

15,    WEST    38th   ST., 

NEW  YORK,  U.S.A. 

The  Leading  Journal  of  the  India-Rubber  World. 

Circulates  in  all  Countries        Founded  in  1889. 

SUBSCRIPTION      -      3.50  dol.  per  annum. 

HENRY  C.  PEARSON,  Editor. 


Le  principal  journal   (en  anglais)  consacre  aux  interets  du 
Caoutchouc  et   de  la  Gutta-Percha. 

FABRICATION.    VENTE.    EXPLOITATION. 

PLANTATION  DU  CAOUTCHOUC  BRUT. 

Fondi-  en  1SS9.       I\rdiL;r  par  des  spicialisies.       Circulation  dans  tous  les  Pavs. 

Abonnement :  Un  an,  3  dol.  50  (17  fr.  SO)  port  pay6. 

Anciens  Nos.  specimens  gratis. 

Tarif  des  annonces  sur  demande. 


EFstklassiges  illustFiePtes  paehblatt 

fiir  die  amerikanische  Gumtni-lndustrie  und  alle 
verwandten    Branchen. 

Gegriindet  1889  und  seitdem  ununterbiochen  unter 

derselben  fachmannischen  Leitung  weitergefiihrt. 


Beschreibung  aller  neuen 
Fabrikations  -  Prozesse 
und  Verbesserungen. 


Patent  -  Berichte. 


Vollstandige    Rohgummi- 
Statistiken. 


Berichte    iiber    Plantagenbau    und    Kautschuk-Qewinnung    in 
alien   Landern. 


Jahrl.  Abonnementspreis  M. 14.— (3.50  Doll.)  franko 

PROBENUMMERN     GRATIS. 


Advertisements  itg 


Published  by  J.  H.  DE  BUSSY,  Amsterdam. 

MERCURY   CODE. 

3rd     EDITION. 

Two  Volumes  with  Supplement   (2,666   4tO.  pages). 
ENGLISH     AND     DUTCH. 


THE    telegraphic   Code    for   communication   between 
Europe  and  Netherlands  last  and  West 
Indies. 

Several  sections  are  relating  specially  to  the 
peculiar  circumstances  and  conditions  of  different 
trades  and  occurrences  in  Java,  Sumatra,  Borneo, 
Celebes,  the  MolucCOS  and  the  other  Islands  of  the 
Indian  Archipelago,  moreover  in  Surinam  and 
Curacao. 

The  Supplement  contains  Estates,  Companies, 
Banks,    Firms,    etc. 

No  Commercial  or  Banking  House  dealing 
with  Dutch  India  can  do  without  the 

MERCURY    CODE. 

Price  SIX  GUINEAS,  excluding  Postage. 

The  Cultivation  of  Hevea. 

A    MANUAL     TOR    THE    PLANTER, 

—  BY  — 

Dr.    P.    J.   S.    CRAMER, 

Director  of  Agriculture  in  Surinam. 

Translated  from  the  Dutch  by 

STUART  R.  COPE  and  A.  CONTENT, 

with    40     Illustrations. 


Price  :     Paper   Covers,   4s.  ;    bound,   5s. 


t2o  ADVERTISEMENTS 


OSTERRIETH  &  Co. 


ANTWERP, 

BELGIUM. 


Banking  Department, 

Wool   Department, 

Colonial  8  Rubber  Department. 


All  Commission  and  Banking  Trans- 
actions. Consignments.  Liberal  ad- 
vances at  best  terms  on  Rubber,  Ivory, 
Cocoa,    Wool.     M.o.P.    Shells,     etc. 


SPECIALITY  :— 

Jtubber  Plantaiion  Jlgenciet. 


CORRESPONDENCE     SOLICITED. 


Tel.  Address:  ^^„        Codes: 

^  A.B.C.,  5th  Ed.    —    A  I. 

OSTERRIETH,  ' 

.  llebers — western  union 

Antwerp.  Mercuur. 


ADVERTISEMENTS 


The  Orgd^n  oftbe  Rubber,  Gutter  Pcrehiy, 
Asbestos. evnd  EleetricSkl  Industries. 

The  Leading  Organ  of  all  Branches  of  the 

RUBBER  INDUSTRY. 

Editor :  HERBERT  WRIGHT,  Assoc.  R.C.S.,  F.L  S. 


Annnal  Subscription  )   Home  -      -     15s. 

Post   Free     -      -     -  J   Colonial  &  Foreign,  16s. 

Specimen  Copy  Free  on  Applicatio'n. 


-:  o :- 


THE    MOST    COMPLETE    NEWS    SERVICE    IN 
THE    WORLD. 

An  Indispensable  Journal  for: — 

RUBBER  PLANTERS, 

RUBBER  DIRECTORS, 

RUBBER  MERCHANTS, 

RUBBER  MANUFACTURERS, 

RUBBER  INVESTORS. 

Send  for  Catalogue  of  Books  for  Rubber  Men. 


MAGLAREN  &.  SONS^  Ltd.^ 

38,   shoe  Lane,  London,   E.G. 


ADVERTISEMENTS 


ii 


Gummi-Zeitunq" 


Established   26   Years. 
BERLIN  S.  61.  BLUECHERSTR,  31. 


The  Most-widely  Circulated    and    Leading 

Paper    on    the   Continent   for  the    India- 

Rubber,     Gutta     Percha,     Asbestos    and 

Celluloid    Industries. 

CHIEF    ORGAN   FOR   THE    WHOLE    SURGICAL   AND 
TECHNICAL    TRADE. 

With    Fortnightly    Supplement. 

'^Die   Celluloid-Industrie/^ 

Official  Organ  of  the   Association   of 
the  German  Celluloid  Manufacturers. 

Published  Weekly.  Subscription  M.  4— Quarterly. 

4  EXPORT    ISSUES    PER    YEAR. 


Advertising  Rates,  2/6  per  inch  per  Column. 
Reduced  Rates  for  Series  Advertisements. 
Special    section    for    Job-line    and    similar 
Advertisements' 


Specimen    Copy    Free   of    Charge. 


ADVERTISEMENTS 


123 


TAPPING    TOOLS, 

When    all    is    said 
that    CAN    be    said, 

YOU'LL     FIND 

there's  nothing  like 


THE 


ICULFEI 


PATENT 


OR 


THE 


PATENT 


FOR 

EFFICIENCY^ 

ECONOMY, 

SIMPLICITY, 

and 

ULTIMATE    CHEAPNESS. 

Not  e. — They  cannot  possibly  injure  the  Cambium,   and 
the  Coohes  Uke  them. 


::o::- 


J.    M.    WOTHERSPOON    &    CO., 

31  (late  23)  GREAT  ST.  HELENS,  LONDON,  E.G. 

Teleg.  Address — "  WeLdable,  London." 


QQ 


124 


A  D  VER  TISEMENTS 


Telegrams:— "WALKERS,"    Colombo,    Ceylon. 

WALKER  SONS  k  GO.,  Ltd, 

COLOMBO     IRONWORKS, 

Colombo   and   Kandy,  Ceylon. 


WALKER  SONS  &  CO,,  Ltd.,  kanTTevS,n 

London  Office— AUCKLAND    HOUSE,  36,  BASINGHALL  STREET. 
Please  see  pages  16,  26,  27,  36,  37,  62,  63.