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HEVEA BRASILIENSIS

PHRA RUBBER

ITS BOTANY, CULTIVATION, CHEMISTRY AND
DISEASES

HERBERT WRIGHT. A.R.C.S., F.L.S..

Late Controller, Government Experiment Station. Pcradeniya. Ceylon ;

Editor, The huiia-Rubher Journal ;

and Author of " Rubber Cultivation in the British Empire," " Seience of Para

Rubber Cultivation," ''Thcobroma Caeao," ete.

THIRD EDITION.

WITH PLATE5 AIND D1A0KAM5.

COLOMBO :
MESSRS. A.' M. iic J. FERGUSON-
LONDON :
Messrs. MacjLarex & Sons.

1908.
[Copyright in Great Britain. '\

A. M. & J. Fkuouson,

I'lilxTBKy AND Publishers.

Colombo.

PREFACE TO THE THIRD EDITION.

Iain writing those notes wliilc enjoying a tour through Ceylon^
^lalaya, Java, and Sumatra under conditions whicii might
lead the average man to go into some Httle detail regarding
rubber trees and their cultivation in the East. But the size of
this book has already greatly exceeded the ditnensions originally
anticipated and I do not therefore propose to write anythin<j;
beyond an explanation of why this edition is being printed.

The first practical work on Rubber cultivation for Planters in
the East was compiled by the Hon. Mr. John Ferguson, c.m.g., in
1883. Some 700 to 800 Planters read that work and not a few
planted rubber ; with 's\ hat wisdom and foresight recent events have
shown. In 190o, while I was Acting Director of the Peradeniya
Department. Mr. Ferguson suggested that I should write a book
on " Para Rubber"; an application was duly forwarded to C4ov-
ernment and their permission to compile and publish the book was
granted.

In the previous edition, written long before the Ceylon Rubber
Exhibition, I pointed out that the industry, as far as growers were
concerned, was in its infancy-. The jiresent edition has been
compiled in consequence of the many advances which have beeii
recently made in methods of cultivation and tapping, coagulating.
and curing operations. I have, since I retired from the Ceylon
Service, had signal opportunities of studying the rubber industry
from man)- points of view ; the wider knowledge thus gained
prompted me to give a more detailed account of essential operations
as carried out by rubber collectors in all parts of the world.

I again express my gratitude to Planters and Otiiciala in IIih
tropics, to maimfacturers in Euroijc, and to the proprietors of the
"India-Rubber Journal", for the information whicli they Jiave
kindly placed at my disposal. Without their assistance the presejit
compilation could not have been published.

H. W.

May, lUOS.

TLLrSTRATTONS.

Faciup; Page

A riantatiou in the Heneratguda Botanic (Jardens Froutispiei-c

Para Rubber Seedlings in Nmseiy ... ... ... ]

Ficus an<l Para llnbbev in Java ... ... ... s

Young Para Rubber, Experiment Station, Buitenzorg, Java ... 9

Leaves, Flowers, Fruits, and Seeds of Hevea brasiliensis ... 11

Para Rubber Trees shedding leaves ,. ... ... 12

Diagram of Latex Tul)es of Hovoa brasiliensis and Carica Papaya 17

Mature Para Rubber in Malacca ... ... ... -J'J

Para Rul)bcr and Cotlee, at 3,rionfeet, South India ... ... '2't

Para Rul)ber in Borneo ... ... ... 'J6

The Oldest Para Rubber Tree in Trinidad ... ... ... '28

Para Rubber on rockj- hillsides, Kalutara. Ceylon ... ... 30

Para Rubber trees 3ii months <^ld, Hunugalla Estate, Kogalla ... 3-i

Yoinig Para Rubber, Madampe, Rakwana, Ceylon ... ... 34

Para Rublier at Bandjasarie, Java ... ... ... 36

Jungle land in South India for rubber cultivation ... ... 37

Root grow-th of Para Riibber ... ... ... 3s

A Para Rubber clearing & niu'sery, South Ceylon ... ... 39

Clearing Land for rubber in Ceylon ... ... ... 40

Young Para rubber plants in baskets: Java ... ... 41

Planting young Para rubber stumps ... ... ... 42

Tapping matme trees, Madampe, Rakwana, Cejdon ... ... 44

Rubber in Malaya : S-year-old trees ... ... ... 46

Thirty-year-old Para rubber trees in Ceylon ... ... 48

Distance in planting : Close planting and thinning out ... 50

Para Rubber and Catchcrops : Rubber and Cassava ... ... 53

Para Rubber and Tea both in bearing: Nikakotua Estate, Matale... 54

Para Rubber and Cacao; Kepitigalla Estate, Matale, Cejdon ... 56

Para Rubber in drained swampy land, Kalutara. Ceylon ... 58

Matuie rubber and tea ; Undugoda Estate, Kegalle,' Ceylon ... 60

Mature rubber in Ambalangoda, Ceylon ... ... ... 62

Para rubber ti-ee.s along river banks, Ceylon ... ... 64

Mature Rubber and Tea ; tapping 15 year-old trees, Holton,

Wattegama, Ceylon ... ... ... 66

Para Rubber at -2,600 feet, Passara (iroup Estate, Ceylon ... 68

Manuring Young Para Rubber Trees ... ... ... 71

Maiuiring Young Rubber Trees ... ... ... 73

Young Rubber and Crotalaria striata ... ... ... 74

Sculfer's & Miller's tapping knives ... ... ... 76

Srinivasagam's knife ... ... ... 77

Efl'ect of bad tapping ... ... ... 78

Secure Knife ; Walker's ^ara Combination Knife ... ... 79

Tisdall's knife ... ... ... 80

Cameron Bros' "Scorpion"' Tapping Knife ... ... 81

Golledge's Knife ... ... ... 82

Safety knife ... ... ... 83

Para chisel ... ... ... 83

Bowman's & Northvvay's knives ... ... ... 84

Dixun s knife ... ... ... 85

Macadam's comb-pricker ... ... ... 86

Macadam-Miller knife ... ... ... 87

Bowman-Northway •' Simplex" knife in use .., ... 8S

Tapping operations on Gikiyanakanda Estate, Ceylon ... ... S9

( viii )

ILLUSTRATIONS ~(C^"/^/-)

Facinj,'
Full spiral s^'stem
\'-Tapping !..

Herring-bone system ...

Drip Tins : tlieiV constr\iction iV application
Double and multiple drip tins
Higb Tapping; at Heneratgoda : base to 50 feet
i'ara Ruliber Trees, two-vtar old : Ambalangoda, Ceylon
Hevea brasiliensis tapped every day
Hevea brasiliensis tapped every alternate day
Basal Tapjung

■Rubber and Cacao in bearing, Dangan Estate, Matab-, Cejdon
Tapping mature trees : Vataderiya Estate, K<!gallo, Ceylon
Tap{>ing Mnlure trees in UMI'i: Arampola Estate, Kurunegala,

Ceyk>n
The Famous I'ara Rubber 'I'rees, whioli have give)\ t-'."! lb.

ruliber in one year, CuUnden Estate, Kalutara
Tapping the renewed bark after l(i lb of dry lubber extracted

in one year
Half sjiiial system : Tree after it has given 14 lb of rubber
old Pai-a Rubber it Tea : Nikakotua Estate, Matale, Ceylon
Latex in setting pans

Da Costa's Patent Rubber Smoking & Coagulating Plant
Michie-Crolledge coagulator
Michie-doUedge scum rubber
The " K. L," Coagulator
Drying Biscuit Rubber
Rolling Macliinery
Passburg Vacuum Drier

Dickson's coagulating and drying machine ...
A rubber washing muchiiio
Heavj"^ washing mill
iiridge's types of rollers
Shaw's rubber washiiifj machine
Kintls of plantation runber
Plantation rid)ber in London
Manufacture of lace rubber
Hydraulic Block Presses
Hand block presses

Pasciation of Para Rubber tree stem ... ••• . .

Illustrations shewing hardy characteristrics of Hevea brasiliensis
Hevea brasiliensis from cuttings ... »«

page
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92
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194
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214
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217
238
240
242
246
248
258
266
272

CONTENTS.

Chapter I. vacr

History of Para Rttbber in the East '... ... )

Work of Wickham, Chapman and Cross— Illustration showing
old trees — Propagation from cuttings from two to three-year-old
trees— Flowering for the first time in Ceylon and the Straits —
First seed in Ceylon and the Straits — Distribution of seeds and
plants from Ceylon — Cultivation — Yields — Preparation — Value —
Export — and Acreage of Para rubber in Ceylon from 1884 to 1908
— Distribution of Ceylon rubber — Acreage in Malaya, Ceylon.
Sumatra, Java, and India — Acreage in all parts of Ceylon during
1906 — Para rubber in Kalutara — Para rubber in India — Rubber
in Federated Malay States, Straits Settlements and Johore —
j! Carruthers' estimate of area planted in rubber in Malaya in
December, 1907 — Para rubber planted in British Borneo — Para
rubber cultivation in Java — Para rubber cultivation in Sumatra
— Para rubber in Samoa.

Chapter II.
Botany of the Para Ribber Tree ... ... ... 11

Characters of the Para rubber tree— Species of Hovea and
their distribution— Illustration of leaves, flowers, fruits and
seeds of Hevea brasiliensis— Foliar periodicity of Hevea brasili-
ensis in Ceylon — Fruit periodicity in Singapore — The laticiferous
system in various plants — Laticiferous system of Hevea brasilien-
81S — Origin — Distribution and characters^Scott on the origin
of the laticifers— Functions of the latex — Observations by Groom,
Warming, Parkin, Ridley, Schulerus, Sachs and Haberlandt—
Water storing — Prevention against insect pests — Reserve food
or excretory — Anatomical details illustratetl.

Chapter III.
Climatk; Conditions for Para Rubber ... ... ... 19

Descriptions of Para by Drs. Trimen and Ule— Para trees in
Brazil— Illustration showing Para Rubber in Ceylon— Climate in
Ceylon, Straits, Perak, Selangor, Seremban, Singapore, Penang,
and Malacca— Java— Rubber-growing areas in Java— Illustration
showing young rubber at the Experiment Station, Buiteiizorg,
Java— Climate in South India— Climate in West Africa— Climate
in British North Borneo— Climate in Samoa— -Climate in the
West Indies— Trinidad— Grenada— Jamaica— Illustration Bht)wing
Para rubber trees in Malacca— Illustration showing Para rubber
trees at an elevation of 3,500 feet in India— Illustration showing
Para rubber trees on Sekong Estate, Borneo— Illustration showing
the oldest Para rubber tree in Trinidad.

(x)

CHAI'TKR IV. ?AOE

Cultivation of Para Rubbri! Tkees

Rate of growth — Sizes of trees at Henaratgoda, Peradeniya,
Edangoda, and parts of Ceylon — Illustrations showing Para
rubber on rocky hillsides and m drained swampy land — Kegalla,
Knuckles, Nilambe, Katngastota, Sabaragamnwa, Wattegania,
Kalutara, Matale, Baddegama — Spread of foliage each year from
2nd to 30th year — Growth on Vogan Estate, Ceylon— Rate of
growth in the Gold Coast — Aburi Botanic Gardens— Tarkwa
Botanic Gardens — African Plantations at Axim— Growth of Para
Rubber trees in Uganda, Liberia and East Africa— Height and
circumference — Rate of growth in Malaya, Perak, Selangor —
Carruthers on rate of growth in F.M.S. — Growth in British
Borneo — Growth in Java and Sumatra— Growth in Jamaica and
Trinidad— Rate of growth in India — Mergui, Shevaroy, Nilgiris —
High average incremental growth in the Straits — Leaf-fall — Root
system — Propagation of plants — Shade and wind in the F.M.S.
and Ceylon — Planting operations-- Illustration showing rubber
clearing and nursery in Ceylon — Nurseries — Distance of seeds in.
and manuring of — Success of basket plants — Fencing— Draining
— Distance, Holing and Planting — Distance in planting — Close
planting and checking rate of growth — Measurements from
estate in Kelani Valley, Ceylon — Systems of planting— Definition
of close planting — Advantages and disadvantages of close planting
— Distance of tapped trees — Original and permanent distances
— Close planting and available tapping area — Number of trees per
acre — Distance for rubber alone and catch crops — Pruning Para
rubber — When pruning should be tried — Principles and enect^
Measurements of straight-stemmed and forked trees in Ceylon —
Increase in girth after fcmr months — An experiment at Peradeniya
— Inter and catch crops— Cacao, Coffee, Tea,Gi-oundimts, Lomon-
grass, Citronella, Cassava or Tapioca, Cotton, Chillies, Tobacco,
Camphor — Future of inter crops — Illustrations showing Para
rubber and cacao at Kepitigalla: — Para rubber and Tea on
Nikakotua estate — Para rubber ami tea on Undugoda Estate,
Kegalla— Para rubber and cacao on Dangan Estate, Matale.

Chapter V.

Para Rubber Soils and Manurfno ... ... ... 57

The mechanical and chemical composition of rubber soils —
Peradeniya — Henaratgoda — Udugaraa — The .soils and rubber
planting in various parts of Ceylon— Carruthers and Bamber on
rubber land and soils in the Federated Malay States— Typical
soils of Malay States— Chemical and physical analyses of soils
in the Federated Malay States by Bamber— Cabooky, alluvial and
swampy soils in Ceylon — Treatment of swampy soils— Illustra-
tions showinw Para rubber on Passara (iroup estate, Passara ;
young and old rubber on Madampe estate, Rakwana, Arampola
estate, Kurunegala ; Para rubber and tea on Nikakotua estate,
Matale ; Para riibber on Hunuwalla estate, Kegalla— The Kelani,
Kegalla, Kalutara, Galle, Matale, Pussellawa, Ratnapura, Amha-
gamuwa, Kurunegala, and Pa.ssara Districts — Analyses of soils in
the West Indies and America — Demerara, Grenada, St. Vincent,
Trinidad, Nicaragua and Surinam— I'rinciples of Rubber Manu-
ring—Manuring to increase the latex— Forest vegeta,tion and
Para rubber trees — Manurinj' old and young trees — Objection to
destroying rootlets — Artificial Manures for rubber soils— How to
apply readily soluble and stable manures — Forking, trenching,

(xi)

1'AgE
and root growth — Results of inanurial experimonts — Ett'ect of
nitrogen and potash — Illustration showing trench-manuring for
young rubber— Constituents in woody stem, twigs, fresh, and
dried leaves — Composition of artificial maiuires obtainable locally
— Green manuring for Para rubber trees — Limit 6 to 8 years —
Suitable herbaceous plants and their composition— Illustration
showing young Para rubber and Crotalaria striata — Tree forms,
Dadaps and Albizzias — Organic matter obtainable— Green man-
uring in Malaya.

Chapter VI.

Tapping Operations and Implements ... ~ ... 77

Importance of tapping operations — The thickness of the bark
tissue, and shedding of dried latex tubes — Eft'ect of bad tapping
illustrated — Tapping knives — Requisites of a good tapping knife
— Recommendations of judges at the Ceylon Rubber Exhibition
— Clean cuts and scraping — Protection of the cambium— Paring
from right to left and left to right— Minimum excison of cortex
and bark — Paring and pricking — Patent tapping knives — Native
implement— Carpenter's chisel — Surgical scrapers and planes —
Beta knife— Golledge's knife, construction and illustration —
Holloway's knives — Mackenzie's knife — Collet's knife — Brown &
Co.'s knives, construction and illustrations — Eastern Produce and
Estates Co.'s knife — Bowman's and Northway's three knives,
construction, method of use, and illustrations— Dixon's knife,
construction, improvements and illustration — Macadam's Comb
pricker — Macadam-Miller paring knife — Miller's knife — The Far-
rier's knife — Pask-Holloway knife— The •' Secure " knife —
Kerkchove's knife — Walker's Combination knife — "Scorpion"
paring knife— Srinivasagam's knife — Tisdall's Knife — Sculfer's
Tapping knife — Bowman-Noi-thway knife.

Chaptek VII.
How TO Tap Paka Rubbek Trees ... ... ... 89

Methods of tapping Para rubber trees— Methods of native
collectors in Brazil and on the Gold Coast — Observations of
Jumelle and Bonnechaux — Modern methods— Single oblique
cuts, illustrated -V incisions, illustration showing a tree after
ten weeks' tapping -Limited area — Herring-bone system-- Photo-
graphs of trees in Ceylon tapped on the herring-bone system —
The zig-zag method and its use— Spiral curves — F. Crosbie Roles
on the spiral method, yields and estimates -Results of the
spiral system in parts in Ceylon — Collecting and storing of latex
— Bury's protector — Centralizing the latex from many trees. —
Drip-tins, their construction and action, illustrated — Keeping
the latex liquid and settling tanks — Method of marking the trees
for tapping — Collecting tins.

Chapter VIII.

Where To Tap ... ... ... ... ... 100

Occurrence of latex in parts of the plant— Rubber from young
parts of trees — Tapping virgin and wound areas — Wound response
and increased yields at Peradeniya, Java, and the Straits —
Interval between successive tappings and wound response —
Arden's results — Clotting of rubber in convex wound areas —

(xii)

I'AGE

Method of formation cf Para milk tubes — Best yioidiiig areas —
Results of experiments from the base upwards in the Straits and
Ceylon — Illustration showing tapping from 6 to 16 feet and base
to 50 feet at Henaratgoda — \ lelds obtained from various levels at
Henaratgoda -Latex from high parts of old trees — Occurrence of
non-coagualable latex.

Chapter IX.

When To Tap. ... ... ... - ... 107

Age or size as criterion — Resin in young trees of Castilloa
Rubber — AnalyBes of rubber from 2, 4, 6, 8, 10-12, and 30-year old
Para rubber trees — Two-year-old tree illustrated— Age of tapping
trees in the Straits— Age of tapping trees in Malacca— Age of
tapping trees in Ceylon— Age and size considered— A manu-
facturer's opinion of rubber from S-year-oId trees — Minimum size
for tapping — How to increase the tapping area illustrated —
Measurements of forked and straight-stemmed trees at Henerat-
goda — The best season for tapping— Tapping during period of
rapid bark renewal— Atmospheric conditions and the flow of
latex— Results in Straits Settlements, Ceylon, Java, F. M. S.
and Nicaragua — Results of Ridley, Haas and Arden— Latex liow
during the leafless phase — Use of ammonia and formalin — What
part of the day to tap — Yields in morning and evening — Compass
tapping— Frequency of tapping and results at Henaratgoda —
Yields obtained by tapping every day, every alternate day,
twice per week, once per week, once per month — Frequency of
tapping on Vallambrosa Rubber Estate — Frequeiicy when tapping
young trees on Lauadron Estate.

Chai'TEk X.

Fields of Para Rubber ... ... ... .- 119

Natural variations — Yields in Brazil and Ceylon — Henaratgoda
trees and Amazon yields — Yields on estates in Ceylon : Matale,
Uva, Kalutara, and Ambalangoda Districts — Illustration showing
the rubber trees on Passai'a Group Estate — 5 to .5! lb. averages
over large acreages — Yields obtained in the Kalutara District for
1905 by the Kalutara Rubber Co., Rayigam Tea Co., N'jl)oda
Tea Co., Vogan Tea Co., Southern Ceylon Tea and Riibber Co.,
Putupaula Tea Estate Co., Yatiyantota Ceylon Tea Co., Ea.stern
Produce and Estates Co., Sunnygama Ceylon Estates Co.,
Yataderiya Tea Co., Kepitigalla and Passara Group Estates,
Ceylon Tea and Coconut Estate Co., Ambalangooa Estate,
Balgownie Rubber Co., Pataling Rubber Co., and Gikiyanakanda
— Yields on Imboolpitiya estate, Nawalapitiya — Illustration show-
inw rubber trees at Peradeniya tapped on the full spiral system
— Exceptional yields at Culloden, Elpitiya, and Peradeniya--
Comparison of yields at Peradeniya and Henaratgoda—Experi-
ments at Henaratgoda — Comparative yields from different
systems of tapping — Spiral and herring-bone tapping compared —
Yields obtained at Henaratgoda in ll months — Results of high
tapping at Henaratgoda from base to .50 feet — High yield from
basal tapping only — 16 tappings yield IV- lb. ruDDer— Average
yielding capacity per square foot of thie bark tissues— Comparison
of yields obtained at Henaratgoda — Illustration showing the
Elpitiya tree after 11 lb. rubber extracted — Yields at Peradeniya
by the V and spiral methods— Rubber from shavings — Rubber

(xiil)

1'A(;k
Vinhls ill Mahij'ii — Yitild from young trees fni Tjiiiiadrmi Kslato -
^ iold fioiii old troes at Siiioaporo- Viul<l during 1906 '"
Fodoratod Malay Status, Straits Sottleinents and Joiiore Viold
during- 19(K) in Selangor, Terak, Nogri Semliilan and Pahang
Yield from the Saiidyuroft llubber Co., 1905 -Variation in yields
in Java — Yields in South India at high elevations Havvtlu)rii
Estate and Mergui Rubber Plantations — Para yields in the(iold
Coast — Y'ields of Para and African Rubber com[)ared — Yield
per tree during 1906 mid 1907 on the properties of the
Consolidated Malay; Anglo American Direct Tea Trading;
Anglo Malay; IJlackwater ; The Kalutara Co.; Kepitigalla ;
Peluiadulla; Yatiyantota; Shelford; Sandycroft ; Ledbury; Yata-
deriya ; Perak : Bukit Rajah ; VallaiiiTirosa ; Highlands and
Lowlands ; Cicely ; Pataling ; Asiatics ; Consolidated Malay ;
Eastei'ii Produce ; Golden Hope ; Shelford ; Union Estate's ;
Bertram ; Balgownie : Kuala Lumpur ; Uidjber Plantatiims ;
Kalumpong Estate — Yield per acre on Kuala Selangor Co. ;
Malay States C<,)ffee Co.; Rubber Growers Co.; Selangor
Rubber Co.; Seremban Estate Rubber Co. -Total yields from
estates in the East from 1905 to 1908 — Official returns for
Federated Mahiy States 19U7 — Yield and distance apart of trees
— Yields on various fields of the Vallambrosa Rubber Co. — -Yields
on fields of the Highlands and Lowlands Estate — Yields from
trees of known girth at Singapore — Cost of Rubber pi'oduction
on properties of Asiatic BLubber and Produce Co. ; Highlands
and Lowlands Co. ; Pataling Rubber Estates ; A'allambrosa ;
Vogan : Y'atiyantota ; Seremban Estate ; P)algownie ; Kuala
Lumpur — Annual increase in output from estates; Gikij'aiiakanda
from 1903 to 1908^ — Difficulty in forming average estimates of yield.

Chapter XL
Effect of Tappinc on the Tkkes .„ ... ... 145

Effect of repetitional bark stripping— Danger of annual cortical
stripping — Excision of Rubber and Cinchona cortex — Excision
and Incision — Pricking and paring in Cej'lou in 19' >8— Effect of
tapping on the foliar periodicity of the trees — Effect of taj)ping
on size and number of seeds — Frequent tapping and reduction
in yield of rubber— Frecjuent tapping and quality of rubber —
Time interval required for accimiulation and concentration of
latex — Reduction in percentage of caoutchouc in the East —
Schidrovvitz and Kaj'e on an abnormal latex with low caoutchouc
contents— Stevens on caoutchouc in latex from 6 and 7 year old
trees— Time interval for maturation of cortex. — Rate of bark
renewal in Ceylon — Rate of renewal on crowded estates and in
inferior soils — Thickness of renewed bark at Gikiyanakanda —
Thickness of renewed bark, 3, 15 and 36 months oh) — Thickness
of renewed bark two years old, at Henaratgoda— Formation of
rubber in situ.

Chapter XII.

Physical and Chemical Propekties of Latex ... ... 154

Physical properties of latex — Coloiu", consistency, alkalinity —
Sap exudations and acidity. Object of producer — Mechanical
impurities — Water in latex— Chemical Analyses of latex of Para
rubber by Seeligmann, Scott and Bamber — Variation in Chemical
composition — Caoutchouc globules— Occurrence, size, density
and Brownian movements— The origin of Caoutchouc in plants —
Resins and Sugary substances in latex — Protein matter in latex

( xiv )

and pntrofaction— Mineral sulistances in latex and their influence
in coagulation — Specific gravity of latex — General characters of
latex — Efl'ect of tempera tine, ammonia, formalin and acids.

PAGfc

CUAl'TER XIII.

The Pkodui'tion ok Rubber from Latex. ... ... 159

Straining latex — Use of porous cloth and centrifugal machines —
Not largely used in Ceylon —Description of centrifvigal machines
in Ceylon — The phenomenon of coagulation — Behaviour of latex
from different species — The Theoiy of coagulation — Henri's work
— Phase of coagulation — Effect of reagents on latex — Torrey on the
structure of crude rubber — Proteins and coagulation — Opinions of
Dunstan, Hpence and Weber — Proteins and Funtumia latex —
Natural coagulation - Artificial methods of coagulation — Spontan-
eous coagulation — Natural heat — Addition of water — Addition of
plant juices— Smoking and coagulation — Native method in Brazil
— Palm nuts and plants to use in smoking — Patent smoking pro-
cesses by Kerckhove, Brown and Davidson, Macadam, Wickham
and Da Costa —Use of alcoholic solution and creosote— Coagulation
by chemical reagents — Use of acetic, formic and tannic acid —
Mercuric chloride— Cream of tartar — Amount of acetic acid tt) be
used — Amounts used on Culloden and Gikiyanakanda -Time re-
<iuired for coagulation— Method of determining the amount of
acetic acid recjuired -Advantages and disadvantages of adding
chemicals to the latex -Influence of coagulant on strength of
rul)ber — Physical properties of rubber prepaiad by various me-
thods— Relation of elastic pi-operties to structure of the coagulum
— Observations by Henri, Si)ence and Torrey — Components of
coagulated rubber — Putrefaction and tacky rubber — ^Analyses of
sound and tacky rubber by Bamber — Use of antiseptics — ^The
necessity foi" washing rubber — Removal of the proteins from latex
— Experiments with Castilloa — Experiments with Para rubber
latex — Uses of ammonia and fcjrmalin — Rapid coagulation and re-
moval of proteins by mechanical means -Biften's centrifugal
machine — Experiments in ('eylon — Aktiebolaget Separator — Mic-
hio-doUedge machine — Matthieu's apparatus — Harvey's coagu-
lator — Coagulation in the field or factory.

CH.iI'TER XIV.

Drying ok Ribbki!. ... ... ... ... IS5

General Methods-Illustration showing the method of drying
biscuit rubber — Water, putrefaction and surface deposits — Chem-
icals and artificial heat for drying-Water in wild and planta-
tion rubber — Removal of moisture from plantation rul)ber —
Immediate removal of moisture from rui)ber by manufacturers-
Effect of moisture on the strength of rul)ber — Reduction of
moisture and increased strength — Experiments by Schidrowitz
ami Kaye— The tensile strength, elongatif)n and resiliency of
dry and moist Funtumia rubl)er samples -Water in and price of
rubber — Creosote and wet i)Iantatioii rubber by Bamber and
Willis — IManufactiners against wet plantation rubber — Methods
of drying in the East — Exposure to the air — Cold air currents —
Hot air rooms — Vacuum drying — Method of using Passburg's
drier — Vacuum dryers in the F. M. S.— Advantages of vacuum
drying — Rapid and slow drying — Manufacturers often prefer
slowly drieci rubber — Bubbles in rapidly dried rubber — Rapid
drying without vacuum driers— Dickson's Machine for coagulat-
ing and drying rubber — Use of calcium chloride — Hot air
chambers and the use of hygroscopic chemicals.

(XV)

CHAPTKU XV. VAC.T

PhV!<I(AL AXn C'lIKMICAr. PuoI'KHTIKS of RllUiKK. ... ... 199

Analyses of Para Rubber from Ceylon, Bukit Rajah, Duckwari,
Arapolakanda, Syston, Lanadron an<l Hawthorn estates, Penaug,
(iold Coast anil the Straits. -Analyses of plantation samples at
Ceylon Rubber Exhibition— Analyses of Ceylon plantation nil)ber
by Schidrowitz and Kaye Analyses by Bamber of Para rubber
from trees oi ditt'erent ages — Analj'ses of Para, Ceara, Castilloa,
Landolphia, Ficus, L'rceolaand Rhynooodia rubbers compared —
Chemical and phjsical properties of rubber — Empirical chemical
analyses and their value — Caoutchouc by difference — (Opinions
of Dunstan — Relation between the physical properties and
chemical composition -Resins— Resins in Para rubber — Resins
in rubber from Castilloa, Manihot, Landolphia, Ficus and
Hancornia species — Resins in crude rubbers from Uganda,
Mexico, Ceylon and Malay by Schidrowitz and Kaye — Removal
of Resins from Rubber— Characters of resin — Resin — Free rub-
bers—Albuminoids in rubber— Ash constituents in washed
rubber — Potassium in washed rubber — The insoluble constituent
— Oxygen — Phj'sical properties of india-rubber— Efl'ect cf
alkalies, acids and halogens— Elasticity, resiliency, colour and
odour — Action of heat on rubber.

Chapteu XVI.

PrRiFicATiox OF Rubber ... ... ... ... -ill

Analyses of washed and dried Para rubber — Purification by
the manufacturers — Lawrence's process for cleaning crude
rubbers — Loss in the manufacture of brands of Para rubber —
Loss in waslnng rubber — Oily and resinous substances and ash
in various rubbers -High loss undesirable — Purification of plant-
ation rubber — Description of rul)l)er washing machine — The
machine at work — Washing scrap ami dirty rubber — CJeneral
account of washing machines — Steam-jacketed rollers — The cut of
rollers — Illustrations showing various typos of rubber machinery
and rollers of different patterns — Macei*ators for bark shavings —
Characters of washed rubber — Rapid washing and drying.

Chaptek XVIT.

Vulcanization and Uses of Rubber ... ... ... 218

Vulcanization of rubber — Heat, sulphur, and india-rubber —
The heat cure and cold cure — The Effects of resins upon
vulcanization of rubber — Low percentage of resin in Para rubber
— The problem of using latex direct — Hancock's experiments —
Colouring latex — Sulphiu-ising latex — Bamber's experiments,
difficulties on estates and in factories and commercial value —
Sulphurising freshly coagulated rubber undesirable — Quantity
of india-rubber in common articles, roller covering, steam pack-
ing, tyre cover, tobacco pouch, garden hose — The composition
of rubber tyres — Analyses by Schidrowitz and Kaye, showing
percentage of india-rubber and substitutes — Analyses by lieadle
and Stevens, showing composition of solid tyres — Uses of rubber
— Purposes for which plantation rubber is useful and useless —
The direct use of plantation rubber — Tests with vulcanized plant-
ation rufiber — Important results by Beadle and Stevens — Synth-
etic ruliber- -Its non-existence— Misuse of the term "Synthetic
rubber' — ArtiHcial rubbers, their general characters and uses —
Composition of artificial rubber — Improvement of low-grade rub-
bers— Substitutes for rubber — Use of vulcanized linseed, rape,
poppy seed, cotton seed and castor oils— Disuse of rubber.

(xvi)
Chapter XVIII. Page

Kinds of Para Rubbkr. ... ... ... ... 23,3

Plantation and fine liard Para— Difterences l^etween Planta-
tion and wild rnbber — Inferiority of plantation Para rubber —
()pinions of india-rubber manufacturers on plantation rubber —
Observations by Burgess— The smoking method of plantation
rubber —Prevention of putrefaction — Chemical and phj'sical
tests — Similarity in chemical composition aufl difterences in
physical properties — Physical properties of rubber from Ceylon
and Malayan estates — Forms of plantation rubbei* — Packing
rubber — Ventilation of packing cases — Biscuit and sheet — Size
and shapes — Crepe — Worm — Conversion of worms into crepe —
Lace — Flake— Scrap — Purification of scrap rubber — Colour of
plantation rubber — Block rubber— Method of preparation— A
commvmication from Lanadron estate — Size of blocks — Blocking
dry rubber — Presses for blocking rubber — Brown and Davidson's
pi-ess— Shaw's block press — Bridge's presses — Kinds of plan-
tation rnbber : manufacturers' advice to planters — Small lots of
rubber: brokers' advice to planters— Analyses of plantation rubber.

Ch.\pter XIX.

DisEAShs OF Para PaTBBER Trees ... ... ... 253

Diseases of plants grown on small areas— Epidemics over large
acreages— Checking disease by tree belts— Forest belts in Malaya

Advantages of mixed products— Block Planting— Retention

of native compounds between estates— Illustration showing hardy
characteristics of Hevea brasiliensis- Diseases of rubber ])lants
—Burrs, twists, and fasciations— Para rubber pests in Brazil
and Java— Pests of nursery plants and stumps— Mites, bees and
wasps, beetles, crickets, cockchafers, Cen'tina species, Pesta-
lozzifi, frey blight— ^7«'ospofiH«i — Leaf diseases of Para rubber
— FmlgT, Hehnint hosporium, Periconia, Cladoi^porium, Macros-
liorlum, Cercospom — Preventive measures — Fruit diseases of
Para rubber— Fungi, Xectria and Phytophthora — Preventive
measures— Stem diseases of Para rubber— Fungi on old stems
and creen twigs- Preventive measures— Die h&ck—Bolnjodlplodia

Corticnm — A l)ark fungus in the Straits — Insects, wot>d-borers,

ants, and slugs— Preventive measures — Tennes Gcstroi and rubber
exudations— Extermination of white ants— Borer in Java— Horned
termite-Root diseases of Para rubber— Fungi in Straits and
Ceylon — Fomos in the Straits— Po/.i/2)oc»s, Uelicobasidium, and
HiymcJioc/tflc'tc- Insects, termites, cockchafers, grubs— Preventive
measure? — A <lisease on prepared rubber —Probable causes &
preventive measm-es- Analyses of black & yellow tacky rnbber
Chemical analyses of tacky and sound rubber — ^ioulds on

rubber.

CiiArTKi: XX.

What to do With the Seeiis

Number of seeds per tree — Seed characteristics — Value — Seed
oil and fat— Meal aii<l cake —Analysis of meal — Cake of Para
rubber seed c()mi)ared with linseed and cotton ciike— Packing
Para seeds for transport — Experiments at Trinidal and Singapore
—Charcoal, sawdust, and NVardian caseB. — Ridley against
Wardian cases.

( xvii )
Chapter XXI. I'aijk

EsTlMATEK OF llUBBER PLANTERS : CO8T8 OF PLANTING RuBBBR IN

Cbylon, Malaya, Java, South India, and Borneo. ... 277

Estimate I. by E. Gordon Reeves, Rs. 322'40 per acre at end
of .">th year for Matale -Estimate II. by F. J. HoUoway, Rs.
•283"r)(» per acre at end of 6th year.—Estimate III., Peradeniya
District for tirst two years — Estimate IV.. Kalutata District for
first six years -Estimate V., Ambalangoda District for first two
years - Estimate VI., Ambalaiio;oda District for first two years
in swampy land Estimate VII., Ambalangoda District for first
two years. Estimate of cost of developing 500 acres under Para
rubber in Malay Peninsula, upkeep of same and returns up to
the eighth year by Stanley Arden — Cost of planting 1000 acres
and profits therefrom in Malaya, by Carruthers Growth on
Seafield ^.states — Cost of planting rubber and profits therefrom
in Java, by Noel Bingley and A. H. Berkhout — Estimate of cost
of 3oO acres of Para rubber in South India, by E. G. Windle. —
Cost of planting Para rubber in Borneo.

Lent by M(ichirc».& Sons.
PARA RUBBER SEEDLINGS IN NURSERY

CHAPTER L
HISTORY OF PARA RUBBER IN THE EAST,

Work of Wickhara, Chapman and Cross— Illustration showing old trees
— Propagation from cuttings from two- to three-year-old trees —
Flowering for the first time in Ceylon and the Straits — First
seed in Ceylon and the Straits— Distribution of seeds and plants
from Ceylon— Cultivation— Yields— Preparation— Value— Export - and
Acreage of Para rubber in Ceylon from 1884 to 1908— Distribution
of Ceylon rubber— Acreage in Malaya, Ceylon, Sumatra, Java, and
India— Acreage in all parts of Ceylon during 1906— Para rubber in
Kalutara— Para rubber in India— Rubber in Federated Malay States,
Straits Settlements and Johore— Carruthers' estimate of area planted
in rubber in Malaya in December, 1907— Para rubber planted in
British Boraeo— Para rubber cultivation in Java— Para rubber culti-
vation in Sumatra — Para rubber in Samoa.

History of Introduction to Ceylon and the East.

THOUGH rubber had been known for many years it was not
until 1875 that the now famous Para rubber was seriously
talked about in Ceylon. In the following year nearly two thousand
seedlings of Hevea hrasiliensis were despatched to Peradeniya,
Ceylon, from Kew. These were contained in Wardian cases and
arrived by the ss. " Duke of Devonshire " in excellent condition,
under the care of Mr. W. Chapman. They were raised from seeds
collected by Mr. Wickham who succeeded in securing 70,000 in the
Ciringals of the Rio Tapajos

Mr. Cross was also sent to South America to bring hom3 plants
in case the transmission of living seed should prove impossible. Ho
arrived at Kew in November, 1876, and brought with him about
1 ,080 seedlings without soil, of which, with the greatest care, scarcely
three per cent, were saved ; from these, about 100 plants were pro-
pagated at Kew and subsequently sent to Ceylon. A photograph of
a Para rubber plantation at Henaratgoda with trees 15 to 20 years of
age is shown elsewliere. The cost of procuring the seeds and plants,
including freight and other expenses, appears to have been no less
than £1,505 4.s. '2d., or an equivalent of about Rs. 11 for every

(1)

2 t^AilA RtFBBEU

Itianl delivered in Ceylon. The whole expenditure was borno
by the Indian Government. Burma, Java, Singapore, and tlio
West Indies also received small consignments from Kew direct
in 187(5.

pROrAGATlON PROM CUTTING AND THE FiRST SeEDS

IN THE East.
*- The plants were first propagated from cuttings, the twigs from
two to thiee-year-old trees being used for this purpose, and a con-
signment of 500 rooted plants was sent, from Ceylon, to British
Burma and Madras in 1878. But as far back as 1873 a parcel of 6
plants was sent from Kew to Calcutta, and another batch of 50
plants was also despatched from the same source in 1877. Burma
obtained about 50 plants direct from Kew in 1877.

The plants at Henaratgoda, 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,
atPerak the small trees only 35 feet high and 2 J years old flowered
in 1880.

The trees at Peradeniya did not flower in 1882, and only 30
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.

Distribution of Seeds and Plants from Ceylon.
After the trees had begun to produce seed the propagation of
plants from cuttings was given up. The seed supply from less than
500 trees has risen from 260 in 1883 to about 200,000 at the present
lime, and every year large quantities of seeds are sent to many
^ropical countries.

India and the Straits have received a considerable number of
Oylon rubber seeds and plants, the first consignments dating back
to 1877 when the cuttings from one-ycai-old trees were sent from
Pfiadeniya. Mr. H. N. Bidley informs me that the Straits do not
appear to have obtained seeds from Ceylon till 1886, when they wero

PARA RUBBER. 3

then distiibuting their own seeds, and ho is unabl to account for
the fate of tlie material sent from Ceylon at an earlier date.
Accordijig to Ridley, it is cleai- 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 m 1879 the Botanic Gardens did not possess any living cuttings
or any plants except those brought by Murton and received
direct from Kew. Seeds were also sent to Queensland in 1886 and
1889, to Jamaica and Buitenzorg in 1887, to Fiji in 1888, to Borneo
and German East Africa in 1891, to Sumatra in 1901, and to tho
Gold Coast, Seychelles, and Australia dm-ing tlie last few years.

Cultivation, Yields, Preparation, and Value, &c.

When Jlerea brasiliensis was first introduced to Ceylon it was
considered to be most suitable for places little above sea-level, but
the good growth obtained at Peradeniya, though less satisfactory
than that at Henaratgoda, was suflicient to interest several plant-
ers, and consequently seeds were supplied to residents in manv
parts of the island. At the present time it cannot be doubted that
Jleve.a brasiliensis will grow in the Central Province of Ceylon up to
2,000 feet above sea-level and in the Province of Uva at a still higher
elevation. This is evidenced by the acreages now imder this
product in the Peradeniya, Matale, Gampola, Xawalapitiya,
Ambegamuwa, Vva, and other districts

Ten or eleven years ago it was thought advisable not to tap trees
until they were at least ten years old, and an estimate of 1 J lb. of
dry rubber per tree, per year, from the 12th to the 20th year was
considered satisfactory. Since that time it has been proved that
some trees when four or five years old may yield rubber of market-
able value, and in exceptional cases individual trees about eleven
years old have given no less than 12 lb. of dry rubber in eight
months, and others as much as 25 lb. per tree in twelve months.
In the same way steady progress is to be seen in the substitution of
paring and spur knives for the carpenter's chisel for tapping opera-
tions ; in washing machinery for cleansing crude rubber, revolving
cylinders for rapidly coagulating rubber, and in the use of chemicals
and hot air apparatus for hastening coagulation and curing the pro-
duct as rapidly and effectively as possible. Sinmltaneously with
general improvements in yield and methods of preparation there
has been a steady rise in price to .3.s\ 6r/.-6.<?. per lb. for some
samples of plantation rubber, and a large increase in tho acreage
under cultivation.

The progress in Ceylon is illustrative of what has taken place in
other tropical countries, and the following tables show the range in

4 PARA RUBBER.

value of Para rubber, export, price per lb., and the approximate
acreage in Ceylon from 1884 to 1908 : — ■

The Range in Value of Para Rubber.

Price of some

Approxi-

Samples of

mate

Plantation

Acreage

Year.

Annual Export.*

Value.*

Para Rubber.f

in Coylon.J

Rs. c. .

1884 ...

nil

.. 2

8 ..

—

1885 . .

cwt.

11.1.17* .

260 0

.. 2

5 ..

—

1886 ...

1 package

9 0

.. 3

0 ..

—

1887 ..

4 packages

110 0

.. 3

2 ..

—

1888 ..

»> •

727 0

.. 3

0| ..

—

1889 ..

542 0

.. 2

9^ ..

—

1890 . .

»> ♦

. 1,067 0

.. 3

6 ..

300

1891 ..

. 2,000 0

.. 3

2 ..

350

1892 . .

cwt.

65.0. 7 .

. 3,325 0

.. 2

10 ..

400

1893 ..

cwt.

52.2. 0 .

. 1,600 0

. .

• — , .

450

1894 ..

cwt.

82.0.14 .

. 4,400 0

10| ..

500

1895 ..

cwt.

15.2.17 .

. 1,290 0

.. 3

550

1896 ..

cwt.

157.0. 7 .

. 8,760 50

.. 3

U '.'.

600

1897 ..

cwt.

73.1. 5 .

. 7,458 0

.. 3

U ..

650

1898 ..

cwt.

24.3.20i.

. 3,694 0

.. 4

4 ..

750

1899 . .

cwt.

70.2.14 .

. 3,838 0

—

1,250

1900 . .

cwt.

73.1.19 .

. 12,882 75

.. 4

0 ..

1,750

1901 ..

cwt.

66.0. 0 .

. 11,986 0

.. 4

H ..

2,500

1902 . .

cwt.

189.0. 0 .

. 38,362 0

.. 4

0 ..

4,500

1903 . .

cwt.

387.0. 0 .

. 84,784 0

.. 5

0 ..

7,500

1904 . .

cwt.

676.0.10 .

.221,120 0

.. 6

0 ..

11,000

1905 . .

cwt.1,401.0. 0 .

.557,945 0

..6to6-8 ..

40,000

1906 ..

cwt.

3,705.0. 0

1,527,539 0

.. 6

3 ..

100,000

1907 . .

cwt.

7,093-0. 0

2,932,119 0

.. 5

8 ..

150,000

1908 ..

cwt.
(Up

3,0520. 0
to 30th, April

1,023,252 0
.)

.. 3

9 ..

165,000

DiSTRIBUTIC

)N OF Ceylon Rubber.

The rubber from Ceylon

in 1905, 1906 and 1907 was (

iistributed

as indicated below : —

Rubbei

•. Oiiantitv.

Countries

to which exported.

1905,

1906.

1907.

cwt.

United Kingdom

1,077

2518 ...

4,266 .

British India

—

119 ...

British East Africa

Canada

—

8 ...

Australia

31 ...

163

Other Bri

tish Possessions in A

sia —

1 ...

Straits Settlements

2 ;

Belgium

55 ...

France

53 ...

Germany

129

124 ...

208

Holland

Italy

United States of America

794 '.'.'.

2,348

Total

1,401

3,706 ...

7,093

* From the Principal Collector of Custom.s, Colombo, Ceylon, f Bulletin of
Miscellsneous Information, Kew, No. 112, 1898. J From the " Ceylon Directory."
§ Official figures.

PARA RUBBER

Acreage of Para Rubber in the East

It is very difficult to form a correct estimate of the acreages
planted with Hevea hrasiliensis in the East, but the following table
approximately indicates the extent of land under this species : —

Countries.

Acreage Planted

1905.

1906-07.

1907-08.

Ceylon

Malaya

Borneo

Java and Sumatra

India and Burma

40,000

38,000

1,500

6,000

8,000

... 100,000 ...
90,000

3,500 ...
20,000 ...
20,000 ...

150,000

147,300

10,.500

74,000

25,000

93,500

233,500

406,800

The Philippines, Fiji, Samoa, New Guinea, and otlier islaiuls in
the East are planting Hevea hrasiliensis ; there will soon be a
quarter-million acres of land planted with this species.

Acreage of Para Rubber ix Ceylon during 1906.

It is difficult to obtain anything approaching a reliable record re-
garding the acreage planted with Para rubber trees at the present
time, but the following table shows* the areas occupied bj' this
product, or about to be planted with it, in a few of the districts
in Ceylon :—

1905. 1007-08

Rubber &

"No. of rubber
Rubber & trees not

Rubber Alone

Tea

Cacao counted under

Acres.

Acres,

Acres.

Acres, other headings:
Number.

Kaliitara

13,394

23,574

6,584

— 415,746

Kegalla

6,521

7,399

2,203

66 48, .500

Puseellawa

2,692

415

1,221

— 136,312

Galle

2,500

4,995

1.142

— 35,000

Kelani

14,000

24,764

13,963

— 689,086

Sabaragamuwa ...

6,200

—

Matalo

1,898

10,826

3,3.}2

5,692 316,625

Ambegamuwa

800

601

.'>04

— 54,976

Kurunegala

—

4,519

—

1,366 23,500

In addition to the above there are in the Ratnapura, Passara,
Badulla, Kandy, Gampola, Polgahawela, and Dumbara Districts,
thousands of acres being planted with Para trees, and there is
every reason to believe that similar expansion is taking place
in Malaya, India, Java, West Indies, Sumatra, Borneo, tropical
America, Africa and other countries. The Ceylon, Indian, and
Malayan public companies alone show over 200,000 acres planted,
and double that area available and probably suitable for rubber ;
in addition to these there are large estates in' private hands which
are rapidly increasing their rubber acreages.

* See Ferguson's Ceylon Handbook and Directory, 1907-08.

6 PARA RUBBER.

Para Rubber in the Kalutara District.
In one district of Ce^^loa alone — Kalutara — tliere are nearly
20,000 acres under rubber, i)lanted during 1904, 1905, and 190f).

1906.

1905.

1904.

Previously.

Total.

r only ... 2,457

3,467

1,744

1,232

8,900

f & other products 1,839

1,330

2,234

5,451

10,854

Total. ... 4,296 4,797 3,978 6,683 19,754

Para Rubber in India.
Though Calcutta was the first country to receive plants of
Hevea hrasUiensis from Kevv in 1873, the acreage under this
species in the whole of India is small when compared with Ceylon
and the Federated Malay States. It is impossible to giv^e the area
occupied by Para rubber tress alone in India, and the following table,
given by Windle at the Ceylon Rubber Exhibition during September,
1906, will show the districts in South India of importance :—

Acres.

The Nilgiris and 8. Wynaad ... 1,200 mostly in coffee (Para cliieHy)

Malabar and S. Wynaad ... 400 (Para, Castilloa and Ceara)

Coimbatore ... ' ... ... 1,100 (Para;

Cochin ... .-■ ... l.W" ,.

Travancore ... ... ... 6,000 ,,

Shevarov Hills ... ... 1,200 (mostly Para in Cofiee)

Pnlneys' ... ... ... KIO

Mysore ... •• ••• —

Uoorg ... ••• ... 2,000 (chietiy Ceara)

Since the above statement was made several companies have
commenced operations in the Travancore district and also in Burma,
and we may soon expect to see, in Southern India and Burma,
about 20,000 to 30,000 acres of planted rubber.

Acreage in Malaya.
The following tables* show the acreages })lanted in tlie Federa-
ted Nfalay States, Straits Settlements, and Johore :

Malaya.
Rubber Statistics vv to the 31st Decembkk, 1906.

F.M.S. Straits Johore. Total.

Settlements.
No. of estates ... 242 5 7 2.54

Total acreage ... 8.5,579 11,341 2,3I(» 99,23o

Opened (luruig 1906, acres 42,154 4,098 l,3.')5 47, 607

No. <tf trees planted up to

the 31 Ht December, 19U6. 10,745,002 1,987,954 147,800 12,88o,7.-,6

Rubber Acrea(je in the Federated Malay States.
Malaya : — In the Federated Malay States a total of 1.50,003
acres lias been reported as alienated for this product. According

• Annual Report, Director of Agriculture, F.M.S., 1906.

l^ARA RUBBEll.

to Carrulliors, llu) following was iJio OHtimaiod acroago nii<l«r
rubber for llu) niiddlo of 190(3 in tlio Federated Malay States: —

Under one year old, 25,000 acres : ojie year and under two years
old, 15,000 : imder three, 4,500: under four, 4,000: under five.
S,500. The following tables show the extent of land jilantcd
with rubber up to the 31st December 1906: —

ISoliUigoi

• Perak

Negri
tSeinbilau

aliaiig

Tota

No. of estates ... Ill)

'23

•J42

Total acreage ... 44, 8*2 1

•-»9,61"2

10,663

483

85,579

Opened during 1900, acres. 19,063

17,678

4,94.->

468

4-J,154

No. of trees planted up to

the 31st December, 1906. 5,477,390

:J,99o,46-'

1,1 96,150

,000 10,

745,00-J

The United Planters' Association, however, in their annual
report for 1906 state that there are 52,843 acres in cultivation in
tlie Federated Malay States alone, of which 49,033 are under
rubber; the low return, as given in the followijig table may be
explahied by assuming that several census forms have not been
entered and returned : —

Of the census forms returned 69 are from Sclangor, 13 from
Negri Sembilan, 12 from Perak, and 3 from Pahang.

Selaugor
Negri Sembilan
Perak
Pahang

Rubber.

37,712$
8,345
4,397$
163

Total. 50,618.^

Crop Returns (Cwt).
19»J6 actual. 19ii7 estimated.
5,674i 9,156

1,594 2,398

•257 717

7,525^

12,271

Para.

Under

Undei-

Under

Uuder

5 years

1 year.

2 years.

3 years.

4 years.

5 years.

& over.

Solangor 16,106

5,783;f

2,968.',

2,705i

1,222.',

8,089$

Negri Sembilan :3, 172

1,284

l,283i

722

335

1,381

Perak 2,281

947

850 "

471

Pahang 163

—

Total. 21,722 8,014:J

5,102

3.521 i

1,618.^ 9,941?

Area Planted in December 1907.

Carruthers has, according to the Ceylon 06aerwr, December

19th. 1907, given a detailed estimate of the rubber planted in

the Malayan States and has concluded thai about 50,000 acres

wvw planted in 1907, making hi round numbers 150,000 acres

g PARA RUBBER.

with 16,000,000 trees, at 107 trees per acre. The following is hia
estimate for December, 1907 : —

Selangor ... ... 63,900 acres.

Perak ... ... 47,300

Negri Sembilan ... 15,600

Pahang ... ... 900

8. Settlements ... ... 16,000

Johore ... ... 3,600

147,300

Para Rubber in British North Borneo.

I am informed by Mr. Cowie, of the British North Borneo
Company, that the total acreage of Para rubber planted up to
31st, December. 1907, in British North Borneo, is approximately
3,605 acres, made up as follows : — •

The British North Borneo Para Rubber Co.

,, Manchester North Borneo Rubber Ltd.

,, Langkon North Borneo Rubber Ltd.

,, Tenom (Borneo) Rubber Co.

,, Sapong Rubber and Tobacco Co. ...

,, Beaufort Borneo Rubber Co.

,, North Borneo Trading and Planting Co.

Rubber in Sumatra.

In a recent issue of the "India-Rubber Journal" it was
pointed out that Rubber is now grown on 44 estates in Sumatra,
and is distributed among the various districts as follows : —

,027

acres

515

703

500

320

500

Serdang

17 estates

Langkat

... 7 „

Padang Redagei
Batoe Bahra

... 6 ,
... 6 „

Labocan Batol

... 4 „

Asaham

... w ,,

Siah

■ •>

Fourteen coffee estates are now, on account of the lowered
commercial value of that product, plantmg rubber; rubber and
coffee in conjunction take up 19 estates; coffee-coconuts-rubber
2 estates ; tobacco-rubber, 4 estates ; tapioca-rubber, 2 estates ;
rubber-coffee-tobacco 1 estate; coffee-rubber-tobacco, 1 estate;
coconuts-rubber, 1 estate, and groundnuts-rubber, 1 estate make
up the remainder. From enquiry made the Ceylon Observer learned
that the acreage under rubber cultivation on the East Coast of
Sumatra was estimated in December 1907 at 20,800 acres.

Planted Acreage in Java.

Mr. J. H. de Bussy, of Amsterdam informed the "India-
Rubber Journal " that it was difficult to state exactly the amount
of laud planted in Rubber m Java. On several estates rubber

Lent b\ Machveii & Sons.

RUBBER IN JAVA.
FICXJS AND PARA. FICUS ELASTIC A 18 MONTHS OLD:
PARA RUBBER 3 YEARS.

Loit by Dr. Tromp tic Haas.
YOUNG PARA RUBBER IN JAVA
KxPKHi.MKNT Station. r.rTTi:N/<>KU.

StTMI-S PKANTKI. I.N JaMAUY, l!Mt4. rHOT()(;KAPM TAKKX IN Dkckmber. 1905.

PARA RUBBER. 9

planting is done on a small scale, but is, however, contijiually
being extondod. The amount of land planted in Ficm elastica
by the Forest Department of Java was estimated on March 31st,
1906, viz:— 13,200 acres; on the same date 1905 at 9,300 acres!
During 1905-6, 4,100 acres have been planted.

On March 31st, 1906, there were said to be planted ; —

In Hevea brasiliensis . . 585 acres.

,, Castilloa elastica .. 200 ,,

,, Funtumia elastica . . 8 ,,

The amount of private land planted in rubber cannot be
stated exactly.

The following total estimate on December 31st, 1906, may
be considered as a creditable one, viz : —

In Java (Public) . . 20,000 acres.

,, Forest Dept., Java .. 14,000

Samoan Rubber Developments.

Samo a appears to be attracting attention among several Contin-
ental firms interested in the cultivation of rubber plants. At the
present time there are only two or three very large companies
which are concerned exclusively with rubber cultivation, and 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 having already secured plants of Hevea bratii-
liensis, Castilloa elastica, Castilloa' elastica variety Alba, Fiends
elastica, Ficus Riyo, Funtumia elastica, ajid Urceola elastica are
now in possession. A fair number of rubber-yielding species of
repute are available for experiment and subsequent selection.

In a report on the trade of Samoa for ISOo the Acting Vicc-
Consul, Mr. T. Trood, gives some particulais of the various rubber
planting ventures in that island.

A new British company, the Upolu Rubber Company, Ltd.,
commenced operations early in 1906, and has ah-eady some 20 J
acres of Para Rubber under cultivation, with cocoa interplanted.

The chief difficult}' — that of transport —having been surmount-
ed, it is likely that a great impetus will be given to rubber
planting in this country.

'2\

10 PARA RUBBER.

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

The Berlin 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 acret^ under cultivation.

— feC^^^gs^^jo--

Photo by II. F. Macmillan.
THE LEAVES. FLOWERS, FRUITS & SEEDS OF HEVEA BRASILIENSIS.

CHAPTER n.
BOTANY OF THE PARA HUB BE R TREE.

Characters of the IV^a rubber tree — Species of Hevea and their
"distribution — lUustriition of leaves, flowers, frait-J and seeds of
Hevea brasilicnsis — Foliar p;n-iodicity of Hovoa brasiliensis in
Ceylon — Fruit periodicity in Singai^ore — Tlie laticiferous system
in various plants — Laticiferous system of H'^vea brasiliensis —
Origin — Distribution and characters — Scott on the origin of the
laticifers — Functions of the latex — Observations by Groom,
Warming, Parkin, Ridley, Schulerus, Sachs and Hal)erlandt — •
Water storing — Prevention against insect posts — Reserve food
or excretory — Anatomical detr^ils illustrated.

Botanical Characters of the Para Rubber Tree.

M. H. Juraelle* devotes considerable attention to the supposed
varieties of Hevea brasiliensis, and, like many other botanists, con-
cludes that the differences in colour, size, and shape of the leaves
described by Ule and others are not constant and may be dis-
regarded. The leaves are trifid, long, and lanceolate.

The flowers are monoecious, and are grouped in panicles of small
cymes ; each inflorescence has two kinds of flowers, male and female.
The calyx is usually five-lobed ; the stamens of the male flowers are
anited in the centre to form a column ; the female flowers usually
possess five staminodes, a small 3-celled ovary, and 3 sessile or
shortly-styled stigmas ; the fruit is a three-lobed capsule, in which
the three oval oleagineous seeds are contained. The seeds are shiny
and speckled brown on the surface.

There are about a dozen species of Hevea recognized by
Midler, Hemsley, and Huber.

The illustrations herewitli given show the characters of the
leaves, flowers, fruits, and seeds of Hevza brasiliensis.

Species or Hevea and Their Distribution.
The genu;; Hevea furnishes the largoi.t quantity, and porliapa
the best quality, of rubber in the world. It if. roprci'.entod by
Hevea brasiliensis, Muell. Arg.,and H. similis, Hoixv.A., hx Brazil,

* Les Plaates a Caoutchouc et a Gutta, by Henri Jumello, Paris, 1903.

PARA RUBBER.

Eastern Peru, and Bolivia; by H. spruceana, Muell. Arg., H.
minor, Hemsl., H. hcnthamiana, Muell. Arg., H. rigidifolia, Muell.
Arg., and H. discolor in North Brazil; by H. pauci flora, Muell.
Arg., in North Brazil and British Guiana; by H. Intea, Muell.
Arg., in North Brazil and East Peru; by H. confusa in British
Guiana, and by H . guianensis , Aub. In the basin of the Amazon
and in the soutli of Venezuela and the Guianas, si^ecies of Hevea
are abundant and scattered among other forest types ; further
north they are rej^laced by Castilloas and Partheniura, and on the
Atlantic side by Manihot and Hancornia.

Among the species of Hevea enumerated above there are several
which yield large quantities of latex, but Hevea hrasiliensis is
probably responsible for the greater part of the Para rubber of
commerce. //. henthamiana has been confused with Hevea
hrasiliensis, 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 ver}- much caoutchouc.

Botanically the genus Hevea has been divided by Huber
(" Ensaio d'uma Synopse das Especies do Genero Hevea sob os pontos
de vista SystematicoeGeographico") into two sections each of which
is subdivided into series. Hevea hrasiliensis belongs to section
Bisiphonia, Muell. Arg., and series Intermediae, and is characterised
by havmg anthers in two complete series, inflorescence pale-yellow
or white, buds of the male flowers acuminate, and obsolete styles.

Foliar Periodicity of Hevea Brasiliensis.

Trees of Hevea hrasiliensis exhibit marked foliar and fruit
periodicities in the East. After the trees are a few years old they
annually pass through a leafless phase; generally, but not always,
they show active fruit production during the months of July
to October.

In Ceylon the trees usually shed their leaves duriiig the hot
season and the following observations apply to some of the oldest
trees in the East : —

Number of Tree
AND Yeak.

I.
II.

III.
IV.

19i)l--,
19112.
19ca

i9(i:{.

1902.
1903.

Lkaf-Fall.

i Commenced
1 November.
! Jan. 1st.

Jiui. 3rd.
j Sept. -29111.

Jan. 4th.

Jan. 21st.

Finished.

Jan. 6th.
Feb. 28th.
Fob. 26th
Novemljer.
Jan. 14th.
Feb. 3rd.

New Leaves
Appeared.

Feb. 2nd.
Feb. 23rd.
March 2nd.
November.
Jan. 24th. ,
Feb. 10th I

Number of

Days

Trees Leafless.

26 days.
3

days.

fj-Ht by Maclarcii & Sons.
PARA RUBBER TREES SHEDDING LEAVES.

I'AKA KUIiBER I.KAVIJS (. OVKlUNd SUM..

PARA IUT]?HKR 13

Fruit Peuiodicitv in Sinoapore.

There is a considerable dill'erence between the trees in i\n)
Suigapore Botanic Gardens and the average maturo trees in Ceylon.
In the Straits, according to Ridley, the trees may bear fruit in any
month of the year; although the period of lioaviest yield is
July-Octol)er with another lieavy \'ield in the m »nth of
March. The followuig table shows tlie total number of seeds
collected in each month for the past nine years in the Singa-
pore Gardens : —

January

•V2.9-24

July

29,650

February

00,8011

August

79,6011

March

... 148,0')I1

September

... :}24,.jl.J

April

56,314

Octobei-

... 29l,4:<(i

May

28,097

November

85,870

June

28,7UO

December

35,8(»7

This agrees more or less with Ceylon, where there is a main or
only fruiting period in the Autumn. (TheUva province is the only
district m C'eylon where there is a special Spring fruit period,
February-April). The best croj) 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 onh' 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 79,000 seeds for 9 completed
years produced no less than 60,850 seeds during that month in
1905.

Ridlej' concludes that (a) while tJiere 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 ; (b) that the
autumn crop is the more uniform of the two, as the spring has only
exceeded the autumn croj^ twice in 10 years ; and (c) that the
autumn fruit periodicity represents the true normal condition of
the tree.

The Laticiferous System.

All the species whicli yield rubbei' are cliaracterised by systems
of sacs, series of cells, or tubes containmg latex ; these occur in
nearly all parts of the plant. The commercial possibilities and
the ultimate success of sevei-al species aio detciininod by the
particular t\q)e of laticiferous tissue which each contains. When
one considers the great difference m the nature, mode of origin,
and development of the laticifers in various plants, there is
every reason for suggesting that each species should be tai)ped
on a jiarticular system in order to take advantage of the pecu-
liarities of each type.

From a study of the laticiferous system of our prominent plants,
1 am convhiced that iji certain mstances the old Jiative and

14 PARARUBBER.

apparently wasteful methods adoj)ted in the extraction of latex are
probably as good as, and even better than, many which have
been evolved.

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.
Generally, these structures 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.

Laticiferous System of Hevea Brasiliensis.

In Hevea brasiliensis the latex is contained in definite duct^
which occur throughout the stems, roots, leaves, flowers, and fruits.
The laticiferous ducts in Hevea brasiliensis consist of a series
of cells, the walls of which break down and thus give rise to
the formation of a number of tubes, disposed more or less longi-
tudinally. In some cases the walls of the cells are only mcompletely
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 m yield of latex and rubber described
elsewhere.

Scott, in his paper (Lin. See. 1885) on the occurrence of articula-
ted laticiferous vessels in Hevea, states that the embryo of Hevea
brasiliensis contains well-developed laticifers, which form a complex
anastomosing system ; numerous and extensive perforations occur
in the lateral walls, tliough the absorption of the transverse walls
may not be complete. Scott believed that the perforation of the
lateral walls commenced at an earlier 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

PARA RUBBER. 15

disappearance of cell walls go on in ilie sec^ondary cortex, and the
laticiforoiis system is, though conimunicative to sonic degree,
relatively disconnected, compared with the straight, open, non-arti-
culated tubes in certain Castilloa and Euphorbia ;.pocies.

This fusion of cells, by the breaking down of the transverse walls
to form larger single channels, goes on day by day in the secondary
cortex, and tlie decomposition necessary requires time for its
completion. The formation of new laticifers cannot be lire-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 de
novo origin hi the secondary bark is accejDted by microscopists.
In a general way it may l)e stated that the longer tlie cortex is
allowed to remaui 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 disconnected (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 brasiUensis j)arts of cross walls may remain, whereas
in the non-articulated types these never exist. The laticifers in
Para 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 gutta-percha yielding plants.

Functions of the Latex.

It is well known that a system of milk tubes may or may not
occur in different species of plants, and that the presence of a latici-
ferous system is of importance in determining the identity of species.
Several natural orders, such as those which include s]-)eeies of
Euphorbia, Castilloa, Hevea, Funtumia, Landolphia, &c., are
characterised by large numbers of plants which possess milk tubes,
whereas other natural orders are not known to have any latici-
ferous species. It is also recognized that the number of species of
plants, possessing milk tubes, is greater in the tropics than in colder
or more temperate zones, and that many of the latex-bearing plants
thrive on rocky soils and in dry districts in the tropics.

If one reflects on the liuiving condition of widely different
species of latex-bearing plants in the temperate, sub-temperate, and
tropical regions, and the behaviour of such ])lants under various
conditions, the difficulty of ascribing a single function or series of

16 PARA RUBBER.

functions to the latex will be manifest. Each species must be
considered separately, and in the case of Uevca brasilieyisis many
observations have been made and various theories propounded.

Groom,* when dealing with this subject, pointed out that there
was no reason to believe that the functions of the latex in all plants
are the same, or that one function should exclude the other.

Function of Storing Water.

The latex of Para rubber consists mainly of water and caoutchouc
globules together with small quantities of sugars, proteids, gums,
resins, mineral matter, &c. Most of the constituents cannot be re-
garded as forming reserve food, and even in the case of sugars and
proteids their presence in such small quantities would prevent their
being of vital importance to the plant in times of emergercy. Fur-
thermore, the fact that the tubes arise, de novo, by a process of
perforation and decomposition, and during 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 very minor import-
ance to the plant.

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.

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.

Parkinf considered that the latex did not play an important part
in nutrition, and inclined to the belief that the laticiferous system
served as channels for holding water in reserve to be called upon
during times of drought. I'he exudation and clotting of the milk
prevent the many insects entering the tree, but this is not of much
importance.

Ridley doubts whether the latex of Para rubber trees acts
as a water-store or a protection against drouglit and points
out that though many laticiferous plants thrive in doseit areas,
the proportion of species belonging to the wet trojiii^al districts
is relatively high. He lays emphasis on the latex as a protection
againwt the ijitrusion of fungus spores and insects into wounds

* Function cf Lcitk'iferoiis Tubes, Anuula of Botany, ISSl).
f Parkin, 1

LATEX TUBES OF HEVEA BRASILIENSIS, 0, 2); AND CARICA PAPAYA (3)
(A) LATKX TUBKS; (B) VESSKL

PARA RUBBER. 17

and states tliat many of the trees of tlie equatorial belt are provided
with either a latex, resin or gum, whicii rapidly exudes when
a wound is made. -

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
ease of IJevea hrasiliensis, resulted in any very bad effects on the tree.

The present appearance of trees, froni which large quantities of
latex hare been extracted, is such as to confirm the belief that
the late:s is of minor importance to plants freely supplied with water,
and that the main source of danger lies in the removal of the corti-
cal and bark tissues often effected in collecting the latex.

It 6 iiould be recorded that Ilevca hrasiliensis grows exceedingly
well on land which is frequently inundated, and in some parts of
Ceylon I have seen trees with tlieir tap roots and a large proportion
of the feeding rootlets permanently under water and yet yielding
over 10 jjounds of rubber, per tree, per year. An abundant supply
of water, in well-drained land, is not harmful to Para rubber trees.

General Considerations.

In fthe accompanying illustrations, figures 1 and 2 represent
the latox tubes running in a vertical direction through the
stem of Ilevea hrasiliensis. 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 tlie milk tubes are pitted, so tliat a transference of
solutions may be effected from one series of cells to the other.
Furthermore, the milk 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 3, drawn from a section of the fruit wall
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 4 the general
outline of a series of tubes is sliown. On account of these relation-
ships one may be inclined to attach some importance to the tlieory
that the milk tubes are partially connected with conducting func-
tions.

But the fact that the laticiferous tubes may be concerned in con-
ducting 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 as water reservoirs.

Generally speaking, the milk tubes contaui an emulsion of many
substances, such as caoutchouc, resin, gum, sugar, proteids, al-
kaloids, and fats, and it is therefore very difficult to identify each
component in sections under the microscope. Schulerus observed

(3)

18 PARA RUBBER.

that in the embryo the latex is rich in suspended matters, 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 milk 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 presence of nuclei in certain laticiferous tubes, absorption in
the embryonic stages, the close association of milk tubes with con-
ducting elements in the leaf, and the occurrence of minute quantities
of carbohydrates, proteids, fats, and peptinizing 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 often diminishes as the result of tapping operations.
But as previously pointed out the occurrence of such mate-
rial in very small quantities prevents one from attributing undue
importance to the " reserve food " conception.

The physiological effect of extracting large quantities of latex
from trees of known age is being studied at Henaratgoda, where
tapping is done more by incision of the laticiferous tubes rather
than by excision of dry cortical tissues, but up to the present no
remarkable phenomena have been observed.

-3©>

CHAPTER III.
CLIMATIC CONDITIONS FOR PARA RUBBER

Descriptions of Para by Drs. Trimen and Ule-Para trees in Brazil-
Illustration showing Tara Rul)ber in Ceylon— Climate in Ceylon,
ytraits, Perak, Selangor, Sereiuban, Singapore, Penang, and Malacca-
Java— Rubber-growing areas in Java— Illustration showing young
rubber at the Experiment Station, Buitenzorg, Java — Climate in
South India— Cli mute in West Africa— Climate in British North
Borneo —Climate in Samoa— Climate in the West Indies— Trinidad —
Grenada— Jamaica— Illustration shomng Para rubber trees in Malacca
—Illustration showing Para rubber trees at an elevation of 3,500 feet
in India — Illustration showing Para rubber trees on Sekong Estate,
Borneo — Illustration showing the oldest Para rubber tree in Trinidad.

(( T)ARA* occupies a position near the mouth of one of the vast
± embouchures of the Amazon in about south latitude 1 , 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 brasiliensis and allied species
are abundantly found. The climate is remarkable for its uni-
formity 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 little 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,t 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 intermixed, and rubber occurs scattered among the

* Notes on Rubber-yielding Plants, by Dr. Trimen.

t Review by Dr. WiUIs, " T.A. & M. C.A.S.," March, 1905.

20 PARA RUBBER.

rest. The lower-lying forests (Vargem or Igapo) are exposed to
yearlj' 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 lains 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 81° 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."

Para Rubber Trees in Brazil.

It has been pointed out by Wickham that the true forests of
the Para rubber 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-to-7-foot trees recorded by Cross.

The foregoing accounts of the climatic conditions in the native
home of Hevea hrasiliensis 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 Para trees can
be grown. But even if the adaptability of the tree were insigni-
ficant, 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 climatic 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 hrasiliensis eliminates many parts
of the tropics for this species. In Ceylon, India, and the Straits
the large tracts of land in the hilly districts cannot be included in
the Para zone on accouat of low temperatures or unfavourable

PARA RUBBER. 21

moisture conditions. In Ceylon an elevation of 2.0(X> 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, HalgoUe estate, on the
borders of the Kelani Valley and Yakdessa districts, at an eleva-
tion 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 for many years.

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

District.

Kalutara (Gikiy
kanda)

Annual

Rainfall.

Inches.

ana-

1.50-74

Average

Annual

Temperature.

Elevation.
Feet.

200

Colombo

87-52

80-7 F. ..

Henaratgoda . .
Kelani

106- 12
161-06

—

33
250

Kurunegala

84-71

—

409

Kegalla

122-33

—

729

Kandy
Badulla

81-52
75-28

75-5
73-4

1,654
2,225

Passara

88-91

—

2,800

Matale

84-38

—

1,208

Ratnapura

GaUe

151-39
91-16

791
79-9

84
48

Kagama

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, Badulla, 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.

The Climate in the Federated SL\lay States.

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

PARA RUBBER.

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 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, &c., 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 11 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

(Telulc Anson), (Kuala Lumpur) (Seremban),
1894-1903. 1894-1903. 1896-1903.

January

February

March

7
8-

April

May

June

8-
7-
5-

July

August

September

October

13-

November

12-

December

13-

Mean Total.

rrti 1 T 1

103-
• 1 t •

5-21

6-46

8-45

10-56

7-81

5-97

4-59

5-96

5-95

919

10-24

7-63

102

88-02

The above details of rainfall will be of value to all interested
the cultivation of Para rubber in Perak, Selangor, and Seremban.
An illustration showing mature rubber on the property of the
Malacca Rubber Plantations is here given.

Photo lent by Doiki'cU & Co.

PARA RUBBER IN MALACCA.
Tappixc Mature Rl'hhkk. Malacca Ruhmrk I'i.antations. Ltd.

PARA RUBBER.

Stngatore, Penang, and Malacca.

lam indebted to the Principal Civil Medical Officer of Singapore
for the following statement showijig the average monthly Rainfall,
Temperature, and Humidity at Singapore, Penang, and Malacca : —

Rainfall.

Temperature.

Humidity.

<£

•S

ce
o

o
C

cS
o
o

Inches.

Inches .

, °Fah.

°Fah.

January

13-47

415

78-2

February

7-26

5-36

78-4

March

5'75

2-62

79-7

69 93

April

io-7r>

6-42

80 • 5

May

4-93

6-27

81-3

Jime

6-50

6-21

81-0

July

6-60

6-66

80-9

August

8-77

9-12

80-5

September

4-65

8-36

80-6

October

5-60

12-86

80-1

November

8-73

10-74

79-1

December

6-96

514

5-33

78-3

79-9

79-1

Java.

Tlie climate in Java varies like that in Ceylon according to the
locality, but we have definite information regarding the climatic
factors at Buitenzorg and East Java.

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 25-3°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 apj)roximating to those at
Badulla in the Uva Province of Cej'lon.

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

I am indebted to Dr. Treubfor the information in the following
synopsis of the monthly rainfall, humidity, and temperature at
PaBceroean in East Java and Buitenzorg.

FARA RUBBER.

Climate puking 1904

ra Java

Rainfall

in mm.

Monthly Average
Mean Humidity.

Monthly Average

Mean Shade

Temperature in °C.

East

Buitenzorg.

East Java.

Buitenzorg.

East Java.

Buitenzorg.

Java

January-

417

221

•2

February

455

192

March

169

287

April

204

May

541

155

June

389

July

312

August

344

September . .

388

—

October

799

November . .

312

December . .

498

110

24-2

27-9

Average

mean, yearly

1901—1904

4,416

1,200

71-9

25-0

27-6

Large areas are likely to be planted by companies in suitable
parts of Java, and it is of importance to notice that the Forest
Department of that island had on March 31st, 1906 approximate-
ly 585 acres in Para rubber. Seeds of Hevea hrasiliensis were
sent to Java in 1887, but the plants in that island at the present
time are mainly young. Illustrations have been seen showing
young rubber on tlie property of Passir Oetjing estate in the
Western part of Java, and satisfactory growth was obtained with
the trees planted nine feet apart. I am indebted to Dr. Tromp
de Haas, for the illustration showing Para rubber at the E.^peri-
ment Station, Buitenzorg, j)lanted as stumps in January, 1904;
the photograph was taken in December, 1905, so that the trees
were then nearly two years old.

I am informed by Mr. R. C. Wright tliat probably the best
parts of Java for rubber-growing are, a portion of Bantam ; a great
part of the Preangor ; a portion of south-east Java ; and porhajis
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 08° F.
to 90"^ F: the humidity, except in a portion of Mid-Java, is high.

Climate in South India.

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

PARA RUBBER.

The accompanying illustration will indicate the growth obtain-
able in the Anamallai Hills, in S. India, at an elevation of 3,500
feet above sea-level. In tliis particular instance coffee is inter-
planted with Para rubber. In South India various species of
rubber-yielding plants are being tried at high elevations, in con-
junction with tea and coffee. The illustration shows Para rubber
and coffee both doing well at a high elevation, and the results
of tapping on an estate in the Shevaroy Hills are given in the
chapter dealing with yields. It is as well to bear in mind that
the elevation up to 3,500 feet, in so far that it is affected 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.

West Africa.

In the Gold Coast, West Africa, it is, according to Johnson, being
grown at an elevation of 1,500 feet above sea-level, where the
average mean temperature is about 81 '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 1900-1904, at Aburi-Gold Coast : —

190(

1901.

1902.

1903. 1 1904.

'as

'3
P4

"3
-3

•

January

1-51

211

0-30

0-73

1-00

Febru&ry

2-30

5 • 32

503

1-09

March

2-72

4-53

3-82

5-89

April

4-88

4-07

701

2-63

May

314

5-48

3-27

4-56

June

.5-72

6-87

7 09

7-44

July

2-48

6-89

2-07

3-72

August

1-49

2-57

2-93

1 - 58

September . .

2-29

6-97

0-73

1-93

October

5-90

4-95

7-16

4-78

November ^

2-53

5-43

2-16

6-60

December

2-69

1-23

0-74

213

3-30

37-65

120

56-42

126

42-31

43 • 08

104

32-09

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

The Aburi Botanic Department regularly distributes large num-
bers of seedlings of Hevea brasilieiuiis to jjlanterson the West Coast,
and wliere the climatic conditions are very favourable this species
is showing satisfactory growth. Several plantations are established

(4)

26 PARA RUBBER.

in West Africa iii districts where from 80 to 100 inches of rain fall
every year ; the results should be better than those hitherto recorded
in the drier climate at Aburi.

Mr. A. E. Evans, in his report upon agriculture in the Gold
Coast Colony in 1906, gives a list of four undertakings which are
planting Para Rubber upon a considerable scale. 12,130 plants
and 259,000 seeds of Hevea hrasiliensis were distributed from the
Botanic Gardens in 1906.

Conditions in Borneo.

Para rubber plants were sent to Borneo from Peradeniya as
far back as 1891, and the illustration herewith given shows
how well this species of rubber grows in that country. The
photograph was obtained from the North Borneo Trading Co.,
Ltd., and represents well-developed trees on the Para estate at
Sekong, being as far as one can judge from the illustration, lightly
and carefully tapped on a system other than the herringbone or spiral.

Mr. Cowie informs 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.

On the coast the temperature averages about 85° F. during
the day arid about 80° F. at night.

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
to one authority * "violent winds and thunder-storms are not of
frequent occurrence, but severe hurricanes sometimes sweep over
the islands, though only in every seven to nine years. The damp-
ness 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. In
the dry season, lasting from April to the end of October, the hygro-
meter shows in the morning and evening about 90 per cent, and over
of complete saturation, but at 2 p.m. about 65 to 75 per cent, is obser-
ved ; this circumstance is very favourable for the drying of cacao."

* Bulletin, Imperial Institute, London, March, 1904.

o "^

UJ u

§ I

CQ ■"'

< =

< ^

Q. ^

PARA RUBBER.

"As regardti rainfau, the record kept at Apia extoads from
1890 onwards. The mean annual rainfall for the 13 years, 1890
to 1902 is 115 inches, and the extretnes in that J)eriod are a
niininuun of 89 hiclies and a maxinuun of 1()3 inches. As far as
quantity is concerned, the ininiiuuin fall is sufficient for cacao
and plants needing nnich water, but on the Samoan 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. If for two or three months
in succession the fall is only 0.8 in. per month the yield is very
seriously threatened, and for this reason suitable localities at
higher altitudes should be sought when selecting land for cacao
planting as the rainfall is heavier in such situations". According
to Wohltmann the climate iji different parts of Samoa is very
variable, the rainfall of selected places ranging from IGOO to
3500 mm. per year, and should therefore be as suitable for Para
rubber trees as it undoubtedly is for Cacao trees.

West Indies.
It is a most remarkable fact that the West Indian islands,
which are well withui the Para rubber zone, have not taken a very
active interest in the cultivation of this kind. A few old trees
occur on some of the islands, and seeds are being applied for in fair
quantities. The following particulars of climatic factors will be of
interest to those contemplating the cultivation of Hevea brasili-
ensis in the West Indies : — -

METEOROLOfilCAL

Details,

R.OYAI. Bd

ANic Gardens, Trinidad.*

Inches of

Mean
Annual re-

Tempera-

Rainfall.

lative Hu-

ture mean

midity.

maximum.

minimum.

annual.

Record for 1887

64-09

79-00

85-90

69-00

77-40

„ ., 1888

65-44

80-00

87-50

69-70

78-60

„ 1889

73-79

77-00

87-57

70-10

78-90

„ 1890

8-2-90

79-00

86-10

69-00

77-50

„ „ 1891

53-74

76-00

87-80

70-10

78-90

„ „ 1892 ...

91-14

80-00

87-02

70-02

78-70

„ 1893

9-2 -49

80-00

87-44

68-58

78-01

„ 1894

52-21

78-00

87-80

69-10

78-45

„ ., 1895

62-23

76-00

87-80

69-50

78-60

„ 1896

66-45

80-00

87 84

70-31

79-07

„ 1897

77-68

80-00

87-91

70-35

79-13

„ 1898

57-63

80-00

87-60

69-20

78-40

„ 1899

46-76

75-00

89-30

69-50

79-40

13 years' average.

68-19

78 -OU

87-51

69-57

78-54

The rauifall at the Botanic Gardens, Trinidad, appears to be
lower than that at Peradeniya, Ceylon, though the average mean
annual humidity is in each case about 78. The mean for 18 years

* (a) Cacao, by J. Hinchley Hart, Trinidad, 19u0 and (b) L' Agricul-
ture Pratiqiie des Pays Chauds, November-December, 1903 ; Etudes at
Memoires, La Trinidad, by Gratien Candace.

PARA RUBBER

was 66-48 inches, and the mean at 49 stations in Trinidad for 1905,
68-10 inches. The oldest Para rubber tree in Trinidad is here
illustrated.

Grenada.
1 am indebted to the Officer in charge of the Botanic Gardens
at Grenada for the followmg information regarding the distribution
of rain in some of the cacao-growing, and therefore probably
rubber-growing, districts of Grenada : —

Rainfall for 1903.

en .

03 ffi

DREW'S
FERM-

NE.

St. John's.

Month.

Q<:

^^^

Pu p3

DOUGALD-

Belvi-

STON.

VERE.

Inches.

Inches,

January

13-75

10-49

6-82

6-69

8-43

15-02

February-

4-89

4-00

1-37

2-00

3-54

4 -.09

March

5-80

4-91

1-03

1-32

1-76

5-54

April

3-54

3-02

0-99

1-34

2-33

3-42

May

4-97

2-78

3-17

5-27

4-11

6-91

June

14-22

12-40

6-88

8-68

10.91

13-17

July

16-77

14-87

11-92

10-13

15-90

22-38

August

23-77

19-10

17-83

21-52

18-82

27-98

September

14-38

11-00

811

11-42

11-07

•20-04

October

15-72

14-18

7-93

iri9

9-26

19-10

November

8-49

5-67

6-02

5-02

4-93

9-08

December

22-90

23-77

10-06

11-52

16-06

20-97

Total

150-20

126-19

82-13

96-10

107-12

168-20

190-2.

136-27

100-57

70-89

66-10

102-34

151-29

Jamaica.

I am mdebted to Mr. Buttenshaw for the following information
regarding the rauifall in various parts of Jamaica
Rainfall Over the Island.
(From about 138 "average" Stations.)

1904.

N.E.Div.

N. Div.

W. C. Div.

S. Div.

The

Island.

Inches.

Inches-

Inches.

January

5-88

2 60

3-01

2-17

3-42

February

8-45

4-19

3-13

2-86

4-66

March

6-07

3-18

11-37

6-74

6-68

April

4-11

4-18

10-26

5-10

5-91

May

6-91

7-33

9-55

6-26

7-51

June

18-27

11-61

17-6-.>

13-31

15-20

July

5-71

2-34

5-77

3-21

4-26

August

7-02

3-25

7-73

3-88

5-47

September

5-66

3-89

9-98

6-42

6-49

October

19-38

9-42

19.41

18-12

16-58

November

17-81

8-60

3-16

1-92

7-87

December

6-85

3-13

3-41
104-40

2 -.36

3-94

Total.

112- 12

63-72

72 -.35

87-99

Lent by Maclarcti & Sons.
THE OLDEST PARA RUBBER TREE IN TRINIDAD

PARA RUBBER. 29

Jamaica possesses plants of an iiidigonoua rubber vitio —Forstero-
via florihunda,\)c.,h\\t m far does not appear to havo taken an
active interest in Para rubber cultivation though saplings of this
species are reported to bo in a tluiving condition.

Accordhig to W. Harris, there are many districts in Jamaica
suitable for the cultivation of Hevea brasilieyisis . " Portions of St.
Andrew, St. Thomas-in-the-p]ast, the lower lands in Portland, St.
Mary, St. Ann, St. Catharine, Upper Clarendon, Manchester, St.
Elizabeth, Trelawny, St. James, Hanover and Westmoreland."

■'■^^

CHA.PTER IV.
CULTIVATION OF PARA RUBBER TREES.

Rate of growth — Sizes of trees at Henaratgoda, Peradeniya, Edangoda,
and parts of Ceylon — Illustrations showing Para rubber on rocky
hillsides and in drained swampy land— Kegalla, Knvickles, Nilambe,
Katugastotaj Sabaragamuwa, Wattegama, Kalutara, Matale, Badde-
gama — Spread of foliage each year from 2nd to 3Uth year — Growth
on Vogan Estate, Ceylon — Rate of growth in the Gold Coast — -Aburi
Botanic Gardens — Tarkwa Botanic Gardens — African Plantations at
Axim — Growth of Para Rubber trees inUganda, Liberia and East Africa
— Height and circumference — Rate of growth in Malaya, Perak,
Selangor— Carruthers on rate of growth in F.M.S. — (irowth in British
Borneo— Growth in Java and Sumatra— Growth in Jamaica and Trinidad
— Rate of growth in India— Mergui, Shevaroy, Nilgiris — High average
incremental growth in the Straits — Leaf-fall — Root system — Propaga-
tion of plants — Shade and wind in the F.M.S. and Ceylon — Planting
operations— Illustration showing rubber clearing and nursery in Ceylon
— Nurseries — Distance of seeds in, and manuring of — Success of basket
plants — Fencing — Draining — Distance, Holing and Planting — Distance
in planting — Close planting and checking rate of growth — Measure-
ments from estate in Kelani Valley, Ceylon— Systems of planting —
Definition of close planting— Advantages and disadvantages of close
planting— Distance of tapped trees — Original and permanent distances
— Close planting and available tapping area— Number of trees per
acre — Distance for rubber alone and catch crops — Pruning Para
rubber — When pruning should be tried— Principles and effect-
Measurements of straight-stemmed and forked trees in Ceylon —
Increase in girth after four months — An experiment at Peradeniya
— Inter and catch crops— Cacao, Coffee, Tea, Groundnuts, Lemon-
grass, Citrcmella, Cassava or Tapioca, Cotton, Chillies, Tobacco,
Camphor— Future of inter crops— illustrations showing Para rubber
and cacao at Kepitigalla : — Para rubber and Tea on Nikakotua
estate— Para rubber and tea on Undugoda Estate, Kegalla— Para
rubber and cacao on Dangan Estate, Matale.

Rate of Growth and Size of Mature Trees in Ceylon.

r"rSHE rate of growth depends upon the nature of the soil and
L 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 quahty, 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. The growth in circum-
ference 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

2
O

> 8-'

UJ '->

O X

E-

z 2

- O

^ X

CD !-

3 -

a
<

PARA RUBBER.

years wlien 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 foflowing
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.

Measurements.

Heiglit

Circumference

Year.

Age.

Feet.

Indies.

1878

1880

—

1881

— .

1882

25|

1883

—

1884

1885

—

1886

—

1887

—

53J

1888

—

1889

—

69J

1890

—

1892

—

1893

—

79J

1905

—

109J

Peradeniya Trees planted in 1876.
Para 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 : —

Xo. of Tree.

1
2

9
10
11

The folloAving hst gives the dimensions of the trees planted in
1881 along the river bank, where they are liable to be flooded wlien
the water is high. They are remarkable on account of the growth

leig

ht.

Circumference in Inches

ft.

in.

3 Feet from Base.

PARA RUBBER.

obtained wlien planted so close, the average distance between the
trees at the present time being 9 to 10 feet.

Circumference, Height.

3 ft. from Base.

Tree.

ft. in.

4 9

57 2

4 2

87 4

4 3

61 7

6 Hi

82 3

6 8

89 1

4 5

81 5

.'. 2 9

52 7

3 7

79 6

5 3

84 2

4 10

86 1

5 5

67 4

5 8

78 9

5 9

64 7

Other measurements have previously been taken of the trees
on the Forest Department Plantations and are here quoted : —

Edangoda Trees.

Age.

2 years

3 „

4 „

Yattipawa Trees.

Mean Circumference,
3 ft. from Base.
4-96 inches.
8-75 ,,
12-96 ..

3 years . . . .9*37 inches.

Rate of Growth in Other Parts of Ceylon,

The following figures show the dimensions of Para rubber
trees, inter planted with tea and cacao, in Ceylon ; —

Circumference of the Stem in Inciies, 3 Feet from tlie Base.

Age of
Trees in

years.
2

3
4
5

T- 11 T.- 11 Sahara- Katugas- Pera- „., , Kalu
Kegalla. Knuckles. „„_„^„ ,J„ .-^ ^ilambe. "^^^

— 14-16

21 to 30^ —

9 —

ganiuwa. tota

27i

Slh

65'

deniya.
2 to*6
10

tara.
5
9
17 to 20

19 — — —

24
38

15 to 46 —

Tn 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 measure 24 to 46 feet in height and 15 to 46
inches in circumference a yard from the ground, and the following
dimensions of the trees referred to will be of interest to those

Photo lent by the Kcgalle Planters' Association.
PARA RUBEER TREES, 32 MONTHS OLD
Hlnucjalla Estaik, Kkc;ai.i,k.

PARA RUBBER.

planters who are trying Para rubber at hicrh elevations in Ceylon
and elsewhere : — " -

y, f Leiigtii of Spread in Circumference

->„"•'" Trunk. Widest P.irt; 3 Feet from the Baso.

"'®®- ft. in. ft. in. in.

1 ... 42 0 ... 29 8 ... 4(5!

2 ... 3G 0 ... 21 (► ... 22J

3 ... 34 0 ... 13 0 ... 15i

4 ... 46 10 ... L>2 (i ... 24

5 ... 42 fi ... 22 S ... 22

6 ... 32 5 ... IS 0 ... 22h

7 ... 36 6 ... 17 0 ... 25'-

8 ... 46 8 ... 25 6 ... 33

9 ... 24 4 ... 13 4 ... 17
10 ... 42 8 ... 29 0 ... 35

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

The Neboda Tea Co., in their annual report for 1905, .state
that "the 1904 clearings range from 17 to 27^ feet in height and
from 6 to 10 inches in circumference, while last year's basket plants,
put out m April -May, from August, 1904, seed, show the best
growth : 8| to 12| feet in height and 3;^ to 4J inches in girth."

Under suitable conditions of .<*oil and climate in Ceylon, one
mus' allow for the full development of the plant; a spread or liranch
diameter of at least 30 feet for trees 10 years old, and 40 feet for 20-
year-old trees might form the basis of calculations where pruning is
not adopted, and where the cultivation is intended to be permanent.

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

Diameter of Branches with Foliage.

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

Tree.s. iviaraio. ganj,.^_ gastota. be. cles. deniya. gamuwa. gama. tara.

Years. ft. ft. ft. ft. ft. ft. ft. ft. ft.

2 2 — 3 — — 3 15 3 8

3 4to4i— — — — — — — 12

4 Uf 12 — — 12 to 13— 19 — 16

6 — 13 — — — — 28 — 17

7 15 to 24 18 — — — — — — 20

8 __ _ 29 — — — 37 — 25

9 _ _ _ 17 to 30 — — — 23 25

10 32 to 34 — — — — — — 28 33

11 -____ — — — — 35

13 ___ — —___. 46

15 27 to 46 — — — — — — — —

25 — — — — — 15 to 43— — —

30 — — — — — 28 to 40 — _ —

Elevation in

feet. 1,2.>0 50 1,500 2,200 2,500 1,5 lO GOO 2,200 100

Rainfall ia

inches. 77 119 85 130 175 90 no 80 to 90 130

(5)

PARA RUBBER.

Where the trees are planted closer than 10 x 15 feet apart they
will probably show a greater height and smaller circumference.
One tree, ten years old, grown more or less in the open, lias a spread
of 36 feet, whereas 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 109 i
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
of 15 to 20 feet in diameter.

Growth on Vogan Estate.

X have been recently favoured with details, by Mr. W. N. Tisdall,
indicating tlie growth of the Para 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 7'72 inches, or at the
rate of 5 inches per annum.

Growth of Para Rubber in Africa.

Evans, in his Annual Report for 1906, states that in the
Akim and other wet districts of West Africa Hevea brasiliensis
should give handsome returns after a few years. Sevei'al estates
in the Eastern and Western provinces are planting Para
rubber in conjunction with other products, and the Botanic
Department at Aburi, Gold Coast, supply plants at reasonable
rates. Evans alsogives the following details regarding the growth
of Para rubber trees, up to December, 1906, at the Botanic
Gardens, Tarkwa : —

Distance

Girth at 3

Trees

Height

feet from

Date of Planting.

planted

December,

ground,

ground.

apart, in

1905.

1D06.

December,

feet.

1905.

1906.

feet

iijch.'s

inches

June, 1904

l.-> by 15

„ ,,

12 ,5 12

July ,

15 „ 15

35 95

20 „ 20

35 5 5 * * ' " '

30 ,, 30

93 59

40 „ 40

55 95 •••

12 „ 12

Aug. tu Sept

12 „ 12

> - ^

CO . K

-1 ? H

IPARA RUBBER. 35

Rate of Growth in the Gold Coast.

Plants have been establislied in the Botanic Gardens,* Aburi,
at diiferent dates, and most of thoni have made favourable growth.
Some of the trees only IS months old were 10 feet high, and had stems
3 inches in diameter. The following table shows the growth of cer-
tain trees at different ages in the Gold Coast : —

Abiri Botanic Gakdenij.

Girth at 3 feet

Age of trees in

oight in

feet

from the

Dat

eof

years.

ground in
inches.

moasur

oniont

30-25

Dec.

19U3

1 >

1905

1903

17-5

6-5 ...

1903

»>

1905

At the present time the cultivation of Para 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 istuied 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 2| inches.

Small plantations of this species have been made in Liberia
and there is every reason to feel satisfied at the growth already
obtained. The v;xperiments made in many parts of East and
Central Africa are not as encouraging as those in West Africa, the
dry climate and occasional fi'ost preventing continuous and rapid
growth. The Hevea plantatioiis in the Congo Free State and
the German Colonies are not yet in a sufficiently advanced state
to allow one to make any very definite assertions.

Growth of Para Rubber trees in Uganda.
According to H. M. Commissioner's Report a Para rubber tree,
4J years old, growing in that Protectorate, was 27i feet high, with a
girth of 12^ 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 product, and
ventures on a large scale were pend'ug during 1906.

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 Para rubber-growing

* Jolinson, Report on Rubber in the Gold Coaat, 1905.

36 VABA RUBBER.

countries. In Perak* 11-year-old specimens may be 70-75 feet
high and have a mean girth of 4i feet, at 3 feet from the base.

Age in Circumference at a Yard Height

Years. from Base in Inches. Ft.

Trees in F.M.S. .. U 17^- —

.. 4 22^ 30

..10 54 65-75

AtPerak.f ..10 60 79

Trees on an estate in Selangor grew to a height of over 30
feet and attained a girth of 19 inches in four years. At Perak,
an 18-year-old tree growing at Kuala Kangsar, has a girth of 8 ft.
6 inches at a yard from the ground. Phenomenal growth in some
parts of the Straits is often met witli, 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.
According to Carruthers the rate of growth in the Federated Malay
States cannot be definitely given, but 3 to 9 inches girth in 2 years,
10 to 30 inches in 4 to 6 years, and 30 to 60 inches in 7 to 10 years
are quoted as averages by him.

Growth in British Borneo.
The measurements of 20 Para rubber trees on an estate belong-
ing to the British Borneo Paia Rubber Co., Ltd,, have been
received. Twelve 20-month-old trees sliow aji average height of 20
ft. 8 in. and a girth of 8| in., at 3 ft. from the ground. Eight
trees 17 months old show an average growth of 19 7-9 ft. in height
and 7| girth. The growth is very satisfactory, and compares
favourably with that in other Eastern places.

Growth in Java and Sumatra.
The illustration given elsewhere indicates the rate of growth
obtained at Buitenzorg, but 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 Para
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 t'eylon.

Hevea plantations in Sumatra have, during the past year,
attracted considerable attention on account of many reports
indicating very rapid growth. A large number of trees are
planted on rich, volcanic soil in areas supplied with over 100
inches per annum ; the rate of growth on many of these properties
appears to be quite equal to the best recorded development in the
Federated Malay States. An average growth, in circumference,
of 5 to 6 inches per annum is accepted for most of the eood
estates in Sumatra.

'Annual Report, F. M. S., for 1902, by Stanley Arden.
t Agr. Bill, of tilt) Straits and F. M. S., Juno, 1902.

UJ
CO X

" 5
<

<
CL

Loit by Mactnroi & Sons.
JUNGLE LAtslD IN SOUTH INDIA FOR RUBBER CULTIVATION-

PARA RUBBER, 37

Growth in the West Indies.
The rate of growth of Hevai hrasiliensis is indicated by the
illustration, given elsewhere, of the oldest tree in Trinidad.
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 a recent issue of the West Indian Bulletin. Shar]) states
that lievea hrasiliensis will not jneld as early or as abundantly
as Castilloa elastica and is not as suitable as a shade tree for
cacao ; he further states that in dry districts, Hevea will probably
thrive better than C'astilloa, on account of its being a much
hardier plant. These statements were intended to apply to
Jamaica only : it is obvious they do not concur with the results of
experience in the East Indies.

The interest in Hevea cultivation in Trinidad is very promising'
Hart states (Bulletin No. 55, July, 1907) that the seeds are in
great demand and that the crop on the Government trees will be
inadequate to meet the demand : he also informs us (Bulletin Xo.
54, April 1907) that the largest tree under cultivation in Trinidad,
dejjicted in the illustration previously referred to, stands a short
distance from the residence of the Governor, Government House.

Hawai, 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 condition;', or otherwise is not clear.

Rate of Growth in Indlv.
The following figures showing the dimensions of nine-year-old
trees in Mergui have been given by Colonel W. J. Seaton :—

Circumference in Inches,
at 2 ft. from the Ground.
29.1
37
38
40i
39l ■

31
18
27

18J

In many parts of Southern India, Para 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

No.
1

Height in Feet.
39

34.i

4
5

43i
36^
38^

362-

38 PARA RUBBER.

On the Shevaroy Hills, at an elevation of 3,400 feet. Para 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 circumference 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 Para and Castilloa rubber.

The Para 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 gu'th of 20 inches in 5 years would be considered satisfactory.

Speaking in quite a general way it is fairly correct to say that
the average growth obtained in the good soils of Malaya, when the
rubber is grown as a single product, is better than that in Ceylon,
India, or in West Africa, but that local areas in each country,
and especially in the drained black soils of Ceylon and along the
Malabar coast of India, show excellent growth of Para rubber.

LT5AF-rAI.L.

The Para rubber tree is not evergreen. During the first two or
three years the young tree may retain its leaves and show a nett in-
crease in foliage at regular intervals. After the second or third year,
however, the tres annually di'ops its leaves, but quickly puts on a
fresh supply of young fohage. When growing under healthy con-
ditions the trees in Ceylon and the Straits usually drop their leaves
in February and March ; in badly-di-ained places the foUar change
is very irregular. The tapping operations are beheved, by many
persons, to change to a varying degree the periodicity of leaf -fall
and production.

In its native home the tree becomes leafless between March
and July.

The annual leaf -fall should be taken into consideration if the
Para rubber 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.

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 successfully for
very many years in conjunction with Para rubber. The lateral roots
grow at varying rates according to the conditions prevailing, but if

ROOT GROWTH OF PARA TREES

^^^vm^:

vm- J- -^

'' ' ' •■••■"' -ii' Jt'

^' -;«J#^

P/wro by Chas. Nortlmhiv.
Paha Trkrs 13 tkars Old and thkir Root Systems.

t*^

Z «

_j a

-<i

PARA RUBBER. 39

grown alone on moderately good and flat land, an incremental
minimum j'early increase in radius of about one to two feet can
be allowed for. In six to seven years the lateral roots (growth
of which is of high importance) of plants distanced 12x12' may
be expected to form a compact mass; planted 10 x 15' the larger
distance will be more or less completely covered in 7 to 8 years.

Rate of Root Growth.
The root system of young Para 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 de-
scribed 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.

Shade in Java and Singapore.

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 Para rubber 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 tr-es 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.

Shade and Wind

In the F.M.S., according to Carruthers, the ."hading 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.

40 PARA RUBBER.

It would be unfortunate if the Para rubber tree required a per-
manent 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 Albizzia moluccana and perhaps Erythrina
lithosperma would conibmo the quick growth and spreading of
branches which would be necessary. Tree? of Peltophorum and
Pterospermum species, &c , though attaining huge dimensions, grow
at too slow a rate — especially when cultivated in conjunction with
other tree forms.

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

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 wmd is a feasible way
out of the difficulty

Planting Operations.

Nurseries. — If clearing and holing have been completed, the
seeds should be planted as soon as they have germinated. The
seeds germinate in a few days if regularly watered. If it is intend-
ed to plant stumps in the following year, a well- prepared nursery
should be used. The seeds can be planted from four to six inches
apart. 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 seeds ;
the same nursery should not be used twice unless it has been
liberally manured. 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. The use of seed-baskets is to be recommended as there is
minimum interruption in the root development during planting
operations ; 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 develop-
ment of the rubber plant is to be regretted. Tlie NebodaTeaCo.,
Ceylon, in their annual report for 1905, attribute the success of
recent clearings to the use of basket plants.

Fevring. — This work is necessary if the vacancies are to be kept
at a minimum. Animals attack the Para rubber plants at all stages,
particularly during the first and second years, and the amount of

L'lit hy Maclarcn & Sons.
CLEARING LAND FOR RUBBER IN CEYLON-

r^li^%^5^S:

,A^ :••■ ^-/VlFA', '-■■:*:

K'--7l^y;H^/,''fY r

Lent by Mcuhircu & Sons.
YOUNG PARA RUBBER PLANTS IN BASKETS: JAVA-

PARA RUBBER. 41

damage done to young clearings by rats, liares, porcupines, pigs,
deer, and cattle cannot be too seriously considered. If 't is intended
to cultivate catch crops whicii 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, &c., 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.

Draining. — It is erroneous to suppose that because Para rubber
is a forest cultivation draining is unnecessary. Draining is as neces-
sary for rubber trees as it is for any other jjroduct in order to
encourage the free circulation of air, water, and food solutions
throughout the soil, and to check wash on steep hillsides.

Tlie 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. An
illustration is given elsewhere to show swampy land which by means
of good drainage has been converted into good rubber soil.

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 70 feet seems sufficient, whereas on
steep hillsides 20 to 30 feet is not too close. The illustration repro-
duced elsewhere, shows a young rubber plantation established on
very rocky land.

Distance, Holing, and Planting. — It is a principle recognized in
forestry that close planting will give tall trees, and wide or open
planting thick trees. The object in planting Para rubber is to pro-
duce trees which wall, as early as possible after the fourth or sixth
year, give a straiglit stem of at least ten to fifteen feet in height and
a circumference of 20 inches or more. Such trees can be tapped.
If the trees are very tall, but have a circumference of less than 20
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, the undesirable result being
tlie outcome of too close planting and not thinning-out or pruning
tlie trees at the proper time. In parts of Ceylon Para trees have

(6)

PARA RUBBER.

Total spread

Age of Trees.

of the Branches

in Diameter, j

^'our years

old

12 feet

Six

15 ,,

Eight

25 '„

Ten

30 „

Twelve

35 ,,

Twelve

35 „

Fifteen

40 ,,

Twenty-

'40 „

been planted 10 ' x 10/ 12 ' x 12/ 14 ' x 14/ 15' x 15/ and 20' x 20/

It should be mentioned that trees in the Federated Malay States,
planted 36' x 36', showed contact of branches in nine years, and in
Ceylon the branches of trees planted forty feet apart liave been
known to meet in ten years.

In order to allow the plants to develop freely in circumference the
maximum distance should be allowed , as the desired length of trunk
is usually obtained even when the Para rubber tree is grown in
the open. From considerations of the condition of trees from 2 to
20 years old, the following table is compiled in order to show the
probable number of Para rubber trees of known age an estate can
bear without interfering with the natural growth of the plants : —

Number of Trees
per Acre.

302
193
70
30
35
35
27
27

This shows the approximate number of trees to the acre at differ-
ent ages without any interference of the branches of adjacent 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 below
about J 00 to 150 to the acre.

Holing. — The question of holing should be well considered, as the
Para rubber plant is a greedy feeder and responds to generous treat-
ment. The holes .should be H feet deep and as wide in area as pos-
sible, and if made 1 1 x 2 x 2 feet they would not be any too large.
The larger the holes, the better for the plant. Good hoUng will give
the plants an excellent start ; the dribbling in of seeds in small
al vangoe holes is not to be recommended. It is hardly necessary
I point out that the planting operations should be carried out when
rain is plentiful ; the plants should, if possible, be stumped but every
care taken to avoid unnecessary destruction of sound roots.
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.

Ltiit bv Miiclarcii & Sous.
PLANTING YOUNG PARA RUBBER STUMPS-

PARA RUBBER.

Distance in Planting.
Johnson recommends planting 15' x 15' to 20' x 20', and after-
wards tliinning-out. If the estate is phmted foi- rubber alone, all
ideas of catch crops are disregarded, and a distance of 10 by 10 feet
adopted in planting, the trees when six years old will certainly have
their foliar and rt)ut systems in contact. On such an estate indi-
vidual trees niiglit be tapped on the full spiral s3-stem until they died,
and thus make room for the further development of the remain-
ing plants. It should be mentioned that there are trees which
have been grown in moderately 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
foliar system measuring less than thirty feet in diameter. I have
frequently seen Para trees which, thougli planted the same distance
and over 10 years old, did not appear to be too crowded.

Distance in Planting and Checking Growth.

The rate of growth is ultimately influenced by the distance tiie
trees are apart ; trees planted about ten feet apart, after attain-
ing a girth of about twenty mches, do not subsequently increase
in girth at the same rate as do those widely planted. On a
Kadugamiawa estate, Ceylon, where the trees are planted about ten
feet apart, those trees on the boundary have contmued to grow hi
cu-cumference after those in the middle of tlie plantation have
almost stopped growing; tlie trees on this block were, at the time
these observations were made, about nine years old and had hardly
ever been tapped. It is, therefore, obvious that a permanent
distance of ten feet apart is far too close for Para rubber, though
many estates have been so planted and will require systematic
thinnmg-out later.

The old Henaratgoda trees, now about 22 years old and orighially
planted about twelve feet apart, measured, according to Willis, 30
mches in girth in 1897; but in 1907 the average girth was only
about 36J inches ; the annual uicrease in circumference having been
much les"? than one inch duruig the last few years

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 Kelaui V^alle}^ Ceylon : —

3<"»-Acnr: Clearing, Planted 1903. TiO by 10 feet).

TRICKS MAKKKI) NOS.

2. 3.

4. 5.

6. j 7. 1 8.

10.

Average.

ins.

ins. ins. ins. ins.

! .
ins.^ ins.

ins.

January,

190G ...

5| 8J

3i 4

5-3

January,

1907 ...

9 15

6 7

8-6

July,

1907 ...

iri' m

7i Si

8j Hi

log

10-3

44 PArA RUBBEIi.

oO-AcRE Clearing, Planted 1904, (15 by 15 feet).

January,
January,

July,

190G
1907
1907

TREES MARKED NOS.

10.

ins.' ins.
1

ins.

3|' 3

lOi

12i

14|

Avers j,^e.

ins.
:{-5
0-9
9-5

These measurements appear to show that the closely-planted
trees after tliree years have an average girth of 5"3 inches against
an average girth of 6" 9 inches for the same aged trees on tiie estate
more widely planted. If these figures represent what is obtainable
by a difference in age alone, they are very valuable ; a difference in
the rate of growth is not usually expected during the first four or
five years. In a later issue of the ' ' i'inancier " the following further
measurements on the same estate, made on September 30th, 1907,
are also given : —

30 Acre Cleaiunc;, 10 by 10 ft. — 1903

Numbers.

Average.

10.

ins.

1118.

ins.

lUS.

ins.

14f

20i

12i

10^^

11-35

50 Acre Clearing, 15 by 15 ft.— 1904.
Numbers.

as. ins.

ins.

ms.
10

ins.
15

111s.
9

ins.
12i

ins.
15i

ins.

10.

ins.
lOi

Average.

ins.
1061

1903 planting (selected trees) 22J ins., as against July, 1907., 2'J.^ ins.
Systems of Planting
It has been previously* explained that in the planting of Para
rubber there are approximately five systems which may be
mentioned : —

(a) Close plantuig — permanent ; (b) Close planting and thiimlng-
out; (c) Wide planting— permanent ; {d) Wide planting with
catch and intercrops; (e) Interplanting with herbaceous and

arborescent plants.

* Science of Para Rubber Cultivation ; Messrs. A. M. & J. Ferguson,
Colombo, 1907. :_•..'■ .■

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V. —
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1>ARA RtlBBER. 46

What is Close Planting ?
To define dose plaiitmg is a difficult uiiitter, and thoiij^'li actual
figures may be quoted, they are subject to juodificatioii according
to the pliysical and chemical properties of tlie soil, and the nature
of the climate in which it is proposed to grow the plants. The
term — close planting — admittedly implies the planting of the tree ;
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
vitality 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 plantijig 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 develo^nnent 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, swam-
py, forest and chena land, from sea-level up to 3,000 feet in Ceylon,
and the allowances to be made accordingly, it may be generally
stated that on a soil sunilar to that at Peradeniya, Ceylon, a dis-
tance often feet apart, or less, for trees of Hevea hrasilitnsis , may
be designated as close plantmg ; one of fifteen feet apart, as medium
distance ; and one of twenty feet apart or over as wide planting.
These distances are subject to modification according to local
conditions, and are here given only to provide a basis for comparison.

Advantages and Disadvantages of Close Planting.

The advantages of close planting are that there is va larger num-
ber of trees on a given acreage ; (2) the ground is better protected
with 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 ])resumably
have a higher value than other trees of economic importance, 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; (1) there may be considerable interfer-
ence 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 thui, 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.

46 tARA RUBBER.

Distance or Tapped Trees.

There is another point whicli appears to have been overlooked
in connection witli this subject, and tliat is the retardation in
growth wliich 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 tap2)able size. Whenever cortical tissues are
removed or mutilated, the energy of the plant is partly diverted
to tlie production of new tissues in the affected area, for the time
beijic 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 tliat the sizes of trees so treated will probably
be less than those of specimens which have never had their
bark so excised and otherwise mutilated.

Original & Permanent Distance.

It is taken for granted that the reader is familiar with the sizes
of Para rubber plants from their first to their thirtieth year, in
different soils and climates ; the question to discuss is wliether the
original should be the permanent distance. No one who has seen
the uncultivated thirty-year-old trees at Hejiaratgoda can doubt
that such specimens require, at the very least, a distance of thirty
to forty feet, if they are to be aUowed to continue in 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 thm, tall stems of
two to four-year-old trees, and the poor lateral spread of the
foliage when trees have just reached the tapjiable 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 regularl^^
tapped, throughout successive years. lam of the opinion that it is
not advantageous to plant, in a clearing. Para rubber trees alone,
at a distance which they will require when thirty years old;
we are deahng with a species which does not, hke 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 Para rubber
trees continue to grow in this mamier and the ultimate size
attainable can only be roughly guessed at from our '.scanty know-
ledge and experience, yet wo knoAV that when their stems are

< <

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CD >:

PARA RUBB?]R. 47

only 20 inches in circumference they yield markctal)le ruhber
in very satisfactory (juantities. Four to six years is a loii<,' titne t(>
wait for the first returns, and from a commercial standpoint
the distance at which trees can be ])lanted. witliout (Mitailinj,' uiuhie
interference in general devel()i)ment, and l)rought 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 implyin'^ the
contrary, a limit to the root and foliar development of Para rul)ber
plants just as there is to parts of other plants.

Close Planting and Available Tapping Area.

The main Justification for closely planting Para rubber trees
is the increased tapping area which is available from the fourth
year onwards.

The object of many persons who planted this product, two
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 PJnd of

Distance of Trees

Number of Trees

the4thor 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 bv 20

109

130,800

From this 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. Tlie
thinnmg-out of Hevea trees is, however, an unsatisfactory })rocess
and very few estates are now being planted with tJiis object in
view. A widely planted rubber estate with an intercrop of cacao
is apparently more valuable and less troublesome than a closely
planted estate of rubber trees only.

48 PARA RUBBER.

The dislaiioe of 10 feet by 10 feet sugsosted on the above
calculations is still open to the objection that tlie soil will be consider-
ably 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 bene-
fit of tlie young Para rubber plants

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.

The use of the Dadap or Albizzia stumps between Para rubber
plants would, I believe, be accompanied by good results. 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 considerations regarding the rate of
growth of the lateral root system.

Pruning Young Trees.

The Para rubber tree naturally grows to a tall slender tree, and
it remains to be seen how by jDruning or pollarding the j^oung plants
an increase in circumference may be obtained at the expense of
the growth in height. Considering what has been accomplished
with tea, where plants ordinarily growing into fairly stout trees
over twenty feet high hav^e been converted into small bushes two
to four feet in height, it would be idle to predict the possibilities with
Para rubber. The prevention of the unnecessary growth in height
may well form the subject of many experiments.

The plants can be prevented from growing into slender woody
structures by removing the terminal bud with a knife or thumb-nail
pruning, or, as is more commonly tlie case, by pruning the ter-
minal young leaves and the enclosed bud. If the central bud is
effectively and repeatedly removed, without doing considerable
damage, the stem cannot grow in height except by means of lateral
shoots ; these will subsequentl}- require bud-pruning once they
have attained the required size. Buds wliich appear in undesir-
able places can be removed in tlie same maimer, the ultimate result
being that a tree considerably forked and sup])lied witli 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 ba.sal
stem increases more rapidly than when the tree is allowed to
grow upwards uninterrupted.

At Henaratgoda tlie trees which have forked at 7,9, and 11 feet
from the ground show an increase of about 30 inches in thirty years

_l
>
liJ

PARA RUBBER. 49

or an average of one inch, per year, throughout a long and fairly
reliable period. Young trees whicli 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 Should 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 growtli of the
remaining stem, and such a measure is not recommended. Old
trees treated in this manner produce foliage 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 ter-
minal bud alone can be easily removed b}' 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 whicli 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.

This treatment has reference only to young clearings of Para
rubber, but, considering how many thousands of acres are being
j'-early 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.

The large acreages of rubber trees planted during the last two
years will in all probability be regularly tapped as soon as they have
attained the proper circumference, and it is therefore necessary to
do all in one's power to help the trees on to the desired condition.
Not only is it necessary to get a return as quickly as possible, but it is
advisable to place the rubber on the market while the price is high,
without unduly taxing the powers of the tree. The lower six feet
of each tree will provide work for about .3 years" systematic and
economic tapping, and the question of high tapping, as at present
being carried out at Henaratgoda and elsewhere, can perhaps be
dismissed.

If the young plants are made to brancli 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 develop-
ment 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.

(7)

PARA RUBBER.

Effect of Pruning Para Rubber Trees.
Dimensions of straight- stemmed and forked Trees in Ceylon.

Average

Direu inference of Trees a yard from the

Age of

Bub-

ber

Trees.

ground.

District.

Straiglit-stemmed
Trees.

Forked Trees.

Average

Number.

Average
Girth.

Number.

Average
Girth.

Difference.

years.

Inches.

Inch.

Galaha

21-33

2514

3-81

Galaha

28-78

88-37

9-59

Kalutara

7-5

8-3

0-8

Mat ale

329

13-9

15-5

1-6

Kalutara

4to7

H to 7A

0-4

Moneragalla

250

Kalutara

old

■Ho.

old

231

Do.

old

Henaratgoda

I 30

10 1 105

Increase in Girth After Four Months.
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 growmg
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 tlie straight-
stemmed one, and it stands to reason that tlie 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 their own whorls of foliage as though
they were members of separate trees, and as they tend to grow
more or loss upwards may themselves require prunmg at intervals of
three or six months.

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 Science of Para Rubber Cultivation; Messrs. A. M. and J.
FerguBon, Colombo, 19U7.

Lent bv Muclarcn & Sons.

DISTANCE IN PLANTING

CLOSE PLANTING ANO THINNINi: OUT.

PARA RUBBER. 61

The two plants roferrod to were over one-and-a-half year old
from stumps, and the forked one showed, four months after pruning,
a circumforence of 4| inches as against 4 mches for tlie straight-
stemmed tree ; tliis means an uicrease of over half-an-inch within
six months of the pruning operation.

The young trees on various estates in Ceylon and the old trees
at Henaratgoda hidicate that an average increase of about one inch
per year may be obtained by making them fork at the proxier height.

If an average mcrease of one inch per year can be obtained, it
means that a year is gained in the first four or five years and the
minimum tapping size of 20 inches may be reached m 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, 18 ■ 1 , and 22 inches respective-
ly. 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 interested 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

Inter and Catch Crops.
Where the rubber plants are closer than 10 to 15 feet the culti-
vation of inter or catch crops is limited to about four to eight years.
Cassava, bananas, cacao, coffee, chillies, groundnuts, lemon grass,
pepper, gingelly, and perhaps tobacco and cotton, are amongst the
most notable products for use under such conditions. If the inter-
crops are such that they can under ordinary circumstances
be grown permanently — as cacao and coffee — it is better to grow
them only in widely-planted rubber clearmgs, and to arrange tliem
between the rubber plants so that a fair root space is available
for alL Cacao and coffee are among the best products to be grown
as intercrops in rubber, and are being cultivated extensively in
India, Samoa, Java, Sumatra, Straits, and Ceylon as permanent
intercrops. Coffee is known to grow well under shade ; in parts of
India it is being cultivated as an inter or catch crop in rubber
clearings, where the rubber plants are planted twenty-four feet apart
and the coffee six feet apart.

52 PARA RUBBER.

If real catclicrops are grown to occup}^ the land from
0 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 for the growth of the roots of the rubber trees
each year, and catclicrops should not be planted witliin the rubber
root area.

The catch crops can be planted one, two, three, and four
feet from one, two, three, and four-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

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 8c?. per ounce, and is obtained
by steaming the freshly-cut grass. A distilling apparatus is re-
quired, and can be kept in constant use by the grass from 300
acres. The fresh lemon grass contains 0-65 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 culti-
vated in parts of Ceylon and the Straits.

Citronella.
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.

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 aro
valued at from £8 to £14, according to size, number of seeds per
nut, and cleanliness. The seeds yield a valuable oil, equal to OUve
oil in quaUty, and the residue after extracting the oil is sold as a
manure — groundnut cake — containing 7 \ per cent, of nitrogen. The
fohage 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 1 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.

PARA RUBBER. 63

Cassava or Tapioca.

'I'licre are several famous Para rubber plantations in Malaya
which have practically paid for all working expenses by cultivating
varieties of cassava as catch crops for the first tliree or four years.
On one ])lantation the rubber was planted 15 by 15 feet ai\d the cas-
sava t) feet apart at the same time as the rul3ber. 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
whicli the cassava cultivation ceased to be profitable. I have been
informed that a crop of tapioca or cassava flour of 1 i to 2 tons per
acre, per crop, is thus obtainable. The proceeds from these crops
have on several estates more tlian 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 tiiis product have
been taken, the six-year-old Para 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.

Cassava thrives best iii good soils and can, according to Lewis,* —
be grown in districts in Ceylon with only 14 inches of rainfall per
year or in districts with over 100 inches per year. The plant is
propagated from the stem, which is cut into pieceo 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 l)e 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 j^eriods 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.

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.

CoTTO^^

The Para rubber growing districts in Ceylon usually have a rain-
fall far in excess of that required for cotton, but in other countries
where rain falls only during certain months and where a drought
can be relied upon, the prospects for cotton as a catch crop m
rubber are somewhat favourable. Rain is required during the

* Mauicu. \fy J. P. Lewis, Govcrnuiunt Agout, Xurthern Provinco,
Ceylon.

54 PARA RUBBER.

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 sufficient 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 oolls give 100 lb. of lint
and 200 lb. of seed.

Para rubber and cotton are being tried experimentally in the dry
Northern Province of Ceylon. The land at tlie Experiment 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 Para 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 Para 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 satisfactorv for a dry, irrigated
district.

Chillies.
These are not cultivated extensively as a catch crop hy 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
until a favourable opportunity occurs to plant. In Ceylon the
planting generally begins in April and picking commences in June,
and continues for five or six months. According to Drieberg, a
chillie plant, with projoer 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 at 15 cents per pound of about 750
chillies. The chillies require to be thoroughly dried or cured before
being despatched to the market.

Tobacco.
Tobacco as a catch crop under rubber has not been largely
cultivated either in Ceylon or Malaya, mainly owing to tlie atmosphere
being too moist. It is largely grown under rubber m Sumatra and

* Cotton, Circular Vol. 111., No. 18, R.B.G., Poradeiiiya.

It)

<;
>.

PARA RUBBER. 55

on a few estates iji Java and Borneo. Tlie time taken from
trasnplanting to harvesting varies from about 70 to 100 days;
and dry weather is necessary towards the beginning of harvesting
time. It may yet bo possible to cultivate either the "wrapping,"
" bmding," or " fillhig " types of leaves during certain seasons
in parts of Ceylon.

The 'Cultivation of tobacco requires very careful selection of
varieties and climate and fre({uently one finds that it is only possible
to grow one variety in a particular local area. The methods of
cultivation depend upon the variety being grown, but in nearly all
cases the plants are first reared in a nursery made to hold from
1,500 to 2,000 seedlings and subsequently transplanted. The
seedlmgs are planted out, in moist weather, when about five to
seven weeks old, and are distanced accordmg to requirements, those
for Sumatra wrappers usually being close together. When the plants
are 1 to H 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 readj^ for harvestmg 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. Tlie 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.

Camphor.
The desirability of growing camphor as a catch or intercrop has
ften 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.

The profitable cultivation of catch crops is limited to about the
first four years, as the products grown cannot be planted close to
the Para rubber trees, and at the end of the fifth year would be al-
most limited to the middle of the lines. Furthermore, they are
all very exhausting.

Future of Intercrops.
The successful and continued cultivation of intercrops with
Para rubber mainly depends on the distance the plants are from one
another. The rapidly-growing surface roots of Para rubber will
ultimately take possession of the soil, and the intercrops of tea,
cacao, or coffee cannot be expected to thrive except the rubber plants
are widely planted. I have seen several examples of 14-year-old
tea planted with 6-year-old Para rubber, the latter 15 by 10 feet

56 PARA RUBBER.

apart ; Iho tea presented a very weak, spindly appearance and could
not be profitably plucked. Thf- cultivation of tea under closely-
planted rubber is niore 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-coun-
try and in parts of Matale , Kegalla and the Uva Province up to 2,600
feet, and in Soutli India up to 3,500 feet. The illustrations given
elfiewhere show properties in Ceylon where tea and rubber are
growing together.

Cacao and colTee planted in the middle of the lines will last
for several years under rubber. The roots of these plants do
not as closely ramify the soil as those of the crowded tea plants,
though they will ultimately have to face the struggle for existence
with the roots of Para 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 protec-
tion of the Para rubber trees against excessive exposure is no doubt
greatly in favour of the two products being grown together. In the
Matale, Dumbara,Kurunegal a. Polgahawela, andiuKandy Districts
of Ceylon, cacao and Para lul^ber as a mixed cultivation is
extendino-. Good results have been obtained on Kepitigalla,
Dangan, Wariapolla 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 iOO cacao trees per acre. Though the rubber ultimately
becomes the stronger component, it is surprising how long both
products can be successfully grown together. In the cultiva-
tion of intercrops under Para rubber it is essential that both
products be planted at the same time, as the Para rubber tree is
about as strong as the coconut palm in its root system and quickly
takes possession of the soil. The illustrations which have been
civen elsewhere, showing Para rubber in association with cacao
and tea in Ceylon and with coffee in Sou h India, could be
considerably increased, but they are sufficient for the purpose and
are worthy of careful study by all rubber planters. Apart from
the question of having more than one product to rely on, it is often
better, for plant sanitation reasons alone, to have mixed i)lanta-
tions; plants of diflere genera grown together are often 'u'lpful to
one another.

The cultivation of pepper among rubber neccessitates permanent
stumps, preferably of the Dadap plant.

Phofo by F. J. HoUoway.
PARA RUBBER AND COCOA-
Kepitigai.la, Matalk, Ceylox.

CHAPTER V.
PAEA RUBBER SOILS AND MANURING.

Tlie mechanical and clicmieal composition of rubber soils — Peradeniya
Henaratgoda — Udugania — The soils and rubber planting in various
parts of Ceylon — Carrutliers and Bamber on rubber land and sols
in the Federated Malay States — Typical soils of Malay States —
Chemical and ]ilijsical analyses of soils in tlie Federated Malay
States by Bamber — Cabookj^, alluvial, and swampy soils in Ceylon
— Treatment of swampy soils — Illustrations showing Para rubber
on Passara Group estate, Passara ; young and old rubber on
Madampe estate, Rakwana, Arampola estate, Kurunegala ; Para
rubber and tea on Nikakotua estate, Matale ; Para rubber on
Hunugalla estate, Kegalla — The Kelani, Kegalla, Kalutara, Galle,
Matale, Pussellawa, Ratnapura, Ambagamuwa, Kurunegala, and
Passara Districts — Analyses of soils in the West Indies and
America — Demerara, Grenada, St. Vincent, Trinidad, Nicaragua
and Surinam — Principles of Rubber Manuring — Manuring to
increase the latex — Forest vegetation and Para rubber trees —
Manuring old and young trees — Objection to destroying rootlets
— Artificial Manures for rubber soils — How to apply readily soluble
and stable manures — Forking, trencliing, and root gi'owth — Results
of manurial experiments — Effect of nitrogen and potash — Illus-
tration showing trench-manuring for young rubber — Constituents
in woody stem, twigs, fresh, and dried leaves — Composition of
artificial maniu'es obtainable locally — Green manuring for Para
rubber trees — Limit 6 to 8 years — Suitable herbaceous plants and
their composition — Illustration showing j^oung Para rubber and
Crotalaria striata — Tree forms, Dadaps and Albizzias — Organic
matter obtainable — Green mamu'ing in Malaya.

IT has been conclusively shown that Para rubber trees can be grown
in soils relatively poor in physical and chemical properties,
and the following analyses of soils in different parts of Ceylon* will

* Circular of the R. B. G. , Peradeniya, by Herbert Wright and A
Bruce, Vol. III., No. fi, July, 1905.

8) '

PARA RUBBER.

illustrate the composition of those which have given good results
with Para rubber :—

Rubber Soils at

Henaratgoda.

1 2

Soil under Soil from

Old Pasture
Rubber. Land.

Fine soil passing 90 mesh
Fine soil passing 60 mesh
Medium soU passing 30 mesh .
Coarse sand and small stones .

Peradeniya

Soils.

Mechanical Udagama
Compo.sition. Swamps.

Per cent. Per cent. Per cento Per cent.

.. 27-00 59-00 20-00 26-00

.. 20-00 36-00 28-00 28-00

9-00 1-00 14-00 21-00

44-00 4-00 38-00 25-00

100-00 100-00 100-00 100-00
Chemical Composition No. 81

Moisture .. .. 4-000 5-600 1-200 1-600

Organic matter & combined water 9-200 20-400 7-800 7-000

Oxide of iron and manganese.. 8-400 1-200 2-800 2-000

Oxide of alumina . . 12-215 5-232 4-960 6-315

Lime . . . . 0060 0-050 0-040 0-060

Magnesia .. .. 0-086 0-115 0-057 0-072

Potash .. .. 0-092 0-06] 0-046 0-038

Phosphoric acid . . 0-038 0-064 0-031 0-031

Soda .. .. 0-095 0-18£ 0-040 0-080

Sulphuric acid . . Trace 0-048 0-007 Trace

Clilorine .. .. 0-014 0-048 0-004 0-004 '

Sand and silicates . . 65-800 67-000 83-000 82-800

100-000 100-000 100-000 100-000

Containing Nitrogen
Equal to Ammonia
Lower oxide of iron
Acidity-
Citric soluble potash
Citric soluble phosphoric acid

0-134
0-163
Nil
Faint
0-006
Trace

0-448
0-544
Mucli
Mucli
0-009
Nil

0-154
0-187
Trace
Much
0-005
Trace

0-134
0-163
Fair
Much
0-004
Trace

Para Rubber Soils in Ceylon

The extension of Para 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 large tracts of land in the up-country districts which are
richest from a cliemical standpoint cannot be included in the Para
zone of the island on account of unfavourable climatic conditions.
The following notes and analyses of Ceylon soils are largely taken
from a circular* dealing with this subject.

*R. B. G. Circular on Para Rubber in Ceylon, No. G 1905.

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PARA RUBBER. 69

Tlie soils ill which rubber is cultivated in Coyloii arc relatively
poor from a chemical standpoint. The organic, matter and com-
bined water vary horn about 2 to 20 per cent., the potash from
003 to 0*04 per cent., phosphoric acid from 001 to 01 percent.,
and the nitrogen from 01 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.

Para Rubber Land & Soils in the Federated Malay States.

I am indebted to Mr. J. B. Carruthers for much information
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,
l^lanted in Para 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.

Mr. M. Kelway Bamber, who recently toured through the Fede-
rated Malay States and visited several of the leading Para rubber
properties, is convinced of the richness of many of the soils and
the suitability of large areas for the cultivation of Hevea hrasilien-
sis. The physical composition of the soils is often remarkably
good, and on Mr. Bamber's authority it can be stated that some
of the samples 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 sometimes as high as 0 • 9 per cent. These high
percentages are not, however, obtainable over all estates in the Fede-
rated 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 ]3er cent. In relation to
Ceylon soils the mineral contents of the Federated Malay States
soils are very often inferior, the chief deficiency being potasli,
rather than phosphoric acid,

Typical Soils of Malay States.

Mr. Bamber, in a report published by Mr. J. B. Carruthers,
stated that " the soils of ^lalaya may be roughly divided into two
distinct kinds.

(a) The fiat alluvial clays or muds on the banks of rivers and
near the sea coast.

60 PARA RUBBER.

(b) The undulating low soils a few miles inland, where they
vary from free sandy loams to heavy clays.

" Peaty soiU on clay usually lying a few miles from the coast.
The alluvial clays or muds are in an exceedingly line state of
division, about 96 per cent, passing through a mesh of 8,100 per
square inch, and the balance througli a mesh of 3,600 per square
inch. Although having the appearance of tine clays there is very
little alumina present, the bulk of tlie soil being composed of very
iinely-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 Para rubber, coconuts, and Liberian coffee. The
amount 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 asli of the
plants, they are not so rich ; although the exceedingly fine state
of division of the soils renders a high i)roportion 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 b}^ ash from the burnt forest, but it
also gradually dimmishes as the drainage water is removed to a
lower level and the soil becomes aerated. Magnesia is present in
ample quantity hi 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 tlie surface soil especially if of a
clayey nature. The proportion of phosphoric acid is also variable,
rangmg from 0'12 to 0'13, the average being about 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 })oisonou;; to many culti-
vated plants. The vigorous growtli of rubber on this class of soil
after drainage is unequalled elsewhere durijig the first years of
growth.

" They are richer in nitrogen than the proportion of organic
matter woiild 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 requirements,
and it is evident from the growth of Para on these soils that there
is no deSciency in any respect."

Photo lent by the Kcgallc Planters' Associntiou.
PARA RUBBER AND TEA IN BEARING

U.NDLCiOUA K^TATK, KlXiAl.I.i:.

PARA IIUBBKR.

The foUowhig analyses woro also given by Mr. Jiamber : —

CliUMlOAL AND PHYSICAL ANALYSIS OF FeDKRAXEI)

Malay States Soils,
mbchanical composition.

Fine soil passing 90 mesh ...

60 „
Medinm soil passing 30 mesh
Coarse sand and small stones

Mechanical Composition.

Alluvial Clays.

Sandy Loams.

96-00
4-00

100-00

Subsoil

95-50

4-50

100-00

68-00
3-2-00

100-00

%
30-00
34-00
26-00
10-00

%
36-00
38-1 0

8-00
18-00

%
26-00
30-00
22-00
22-00

100-00 100-00 100-00

CHEMICAL COMPOSITION.

Moisture

6-920

5 -.560

5-UOO

1-400

4-000

2-200

Organic matter and com-

bined water

24-080

16-640

8-000

3-000

n-6(to

5-600

Oxide of iron and manganese

1-120

1-200

3-0(0

0-300

8-240

()-7(iO

,, ,, alumina

2-971

3-019

2-5-20

1-165

4-183

2-516

Lime

0-284

0--200

0-160

0-140

0-160

M agnesia

0-252

0-381

0-230

0-130

0-100

0-130

Potash

0-131

0-169

0-014

0-O14

0-053

0-030

Phosphoric acid ...

0-025

0-012

0-076

0-051

0-064

Sand and silicates

64-200

72-800

81-000

93-800

73-600

88-600

Chlorine

0-017

0-019

100-000

Containing nitrogen

0-667

0-425

0-403

0-492

0-386

0-403

Equal to ammonia

0-810

0-516

0-489

0-598

0-469

0-489

Lower oxide of iron

Much

Fair

Good

Acidity.

Marked

Cabooky, Alluvial, and Swampy Soils, Ceylox.

' ' Cahook. — 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 per cent, of potash, 0010 per cent, of phos-
phoric acid, 0-060 percent, of lime, and 0128 per cent, of nitrogen."

'* Alluvial soil. — 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.

62 PARA RUBBER.

' ' 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.

' ' The particles are arrested and precipitated all along the bank
of the river during flood time. During heavy floods very large quan-
tities 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 1 1 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 Para rubber grow^
exceedingly well in such soils and continues to thrive therein for over
twenty years in the Peradeniya District.

" Swamps. — The cultivation of rubber in such areas has, during
tlie 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 otherwise sour soils.

' ' In some cases each rubber tree should have a separate drain-
age 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."

One analysis shows the soil to contain 20-4 per cent, of organic
matter and combined water, 005 per cent, of lime, 0'061 per cent,
of potasii, 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 application of lime or by burning.-

Treatment of Swampy Soils.
In the S- raits Settlements and Federated Malay States and in
parts of C -ylon drained swamps have been proved to grow Para
rubber ; in the former place large sums of money have been

P/ioto by D. L. Gi)onciL'cirdi(ne.
MATURE RUBBER IN AMBALANGODA
Tapping 11-yi;ar old Thkks. nKviirRAi Esiatk, Ei,1'itita, Ckyi-on.

PARA RUBBER. 63

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 tlie soil being aerated, and to some extent
may hinder the free oxidation of the humus. Owing to the ex-
tremely fine state of division the soil can retain large quantities of
water, due to the particles being in such close contact with one an-
otlier that they form a very large number of capillary tubes whicli
become full of water. Again, such a soil may suffer during periods
of drought, as it is difficult to get tlie air out of the capillaries. A
water-logged soil is usually cold and therefore generally unsuitable
for cultivation, unless it can be modified both pliysically 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 suf-
ficient to char the vegetable organic matter ; the heaps should then
be distributed over the surface. There is a loss of nitrogen and or-
ganic matter, but the physical condition of the soil is improved,
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 mucli 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 jjlant food,
and should have occasional dressings of potash and phosphatic
manures, basic slag, and sulphate of potash or kainit being consid-
ered suitable."

Para Rubber Soils ly various Districts in Ceylon.

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
Circular previously referred to is liere quoted.

Kelani Valley District.
According to the report of the District Planters' Associa-
tion, for the year 1905, it was estimated that there were about
14,000 acres planted in rubber alone in addition to a large acreage

64 PARA RUBBER.

interplanted with tea. The abundant rainfall and high tempera-
ture together with tlie moderately good soils in the Kelani district
seem very suitable for Heven brasiUensis .

" 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 percent.: 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 02 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 0"2 per cent.; and the phosphoric acid from
traces to 0*07 per cent. In some cases the high percentages of or-
ganic 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 proportions of the ingredients
which may be expected in the district ; they do not represent the
maximum and minimum compositions."

Kegalla District.
The Kegalla District might also be considered in connection with
the Kelani, as the soil and climate appear equally suitable for Para
rubber. According to the 1905 report of the District Association,
the Kegalla planters then had over 6,500 acres of rubber, either
alone or interplanted with tea. Good growth has been obtained in
clearings only 10 and 18 months old on the Mabopitiya, Dickellia,
Waharaka, Parambe and other estates in this district, and the tap-
ping of trees from 12 years upwards on Yataderiya and Undugoda
estates has been accompanied by profitable yields. On many of
the estates in the Kegalla district, the Para rubber is interplanted
among tea ; the illustration elsewhere shows both products doing
well on Undugoda Estate, Kegalla. Elsewhere illustrations are
given showing trees only 32 months old on Hunugalla estate, and
tapping of mature trees on the property of the Yataderiya Tea
Co., all in the Kegalla district.

I.rnt by M .
PARA RUBBER TREES ALONG RIVER BANKS CEYLON

PARA RUBBER. 66

Kalutara District.

During the year 1905 the acreage under Para rubber in the
Kalutara District was largely increased. The report of the District
Association for 1905 showed 6,038 acres in rubber alone, and 7,256
in rubber planted through tea, making a total of 13,394 against
the figures (for 1904) of 3,128 acres in rubber alone and 6,759
planted through tea. It is obvious that during 1906 a consider-
ably larger acreage of new land was planted, but it is not thought
that very much more tea will be planted up with rubber. In addition
to the above, large acreages are being planted by European and
native proprietary planters in the district.

Several illustrations are given showing the growth of Para
rubber trees in various parts of the Kalutara District, some of
them in the young stages, others mature and now being tapped.

South of Kalutara, in the Galle District, soils of similar
character are met with and swamps frequently occur. According
to the report for 1905, no less than 2,500 acres were then in
Para lubber and other 2,500 acres were estimated for 1906.

Mechanical Composition. — " The soil analyses show a slightly
coarser texture than those examined from the Kelani ; usually
from 1 1 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 variation
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 0' 1 to 0' 15 per cent. This is of course excluding
swampy areas, which we have seen to be very rich in organic matte
and nitrogen, and alluvial soil such as that quoted below. The
potash varies from 0'04 to 0*2 per cent, and usually shows a re-
lation to the amount of magnesia, both being derived from the de-
composition of double silicates. The phosphoric acid varies from
a trace to 0"06 per cent., and this low percentage is common in most
Ceylon soils. The hme varies from 0"03 to 0" 15 per cent, and the
magnesia from 0*04 to 0'2 per cent."

IVIatale District.

It is almost impossible to give the acreages under rubber in
the Matale District, but as far as can be gathered there were about
1,359 acre> of cacao interplanted with rubber, and 539 acres
in rubber alone in 1905. Tlie accompanying illustration shows
Para rubber growing on Dangan estate, the property of the
Rubber Plantations, Ltd., where tlv^ rubber and cacao trees were

(9)

f)G PARA RUBBER.

about 5| years old both being in bearing. Another photograph
shows Para rubber in association with tea, both in bearing and
doing well, on Nikakotua estate in the same district.

It is well known that the Matale District contains some very
old Para, lubber trees, 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 now 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
c?nt. 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 ,rom 3 to 6 per cent.

Chemical Composition. — " The organic] matter usually varies
from 8 to 14 per cent, and the nitrogen from 0* 1 to 0*2 per cent. ;
the lime from 0"08 to 0'2 per cent. ; the magnesia from 0'05 to
0*25 per cent.; the potash from 0'03 toO'25 percent., and the
phosphoric acid from 0"01 to O'l per cent."

PUSSELLAWA DISTRICT.

In the Pussellawa District the soil and climate appear to resem-
ble those in sections of the Peradeniya and Matale Districts, and
although part of the district is considered to be too high for Para
rubber, there were, early in 1906, nearly 2,700 acres' of this product
planted alone or with tea.

Ratnapura, Sabaragamuwa and Ambagamuwa.
The Ratnapura District, differing so widely from the foregoing
in having such a heavy rainfall and being one already extensively
cultivated in rubber, is here synoptically dealt with.

Regarding the mechanical composition, " out of about a dozen
soils 17 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 of moisture varies from 3 to 5. The chemical composition
shows from 10 to 12 per cent, of organic matter, O'l to 0*2 per
cent, of nitrogen, 0*06 to 0*2 percent, of hme,0"07 to 0'15
per cent, of magnesia, 0*04 to 0" 1 of potash, and from 0" 03 to 0*8
per cent, of phosphoric acid." Para rubber is being extensively
planted in this and the surrounding districts.

Photo by Volombo Apothecaries Co. Lent by M Seoiven.

PARA RUBBER IN CEYLON
Matl-he Rubber and Tea; Holton Estate, Wattegama.
Tapping 15 Year-Old Trees.

PARA RUBBER. 07

According to information supplied by the Secretary of tho
Sabaragainuwa Planters' Association, the acreage of tea inter-
pianted with rubber early in 1900 was 4,477 — in rubber alone 1,743
acres — and during the past two years several large tracts of land
have been cleared and planted with Para rubber. Tlie photographs,
showing the growth of Para rubber at Madanipe, Rakwana,
are all the more interesting as indicating the possibilities in
this district.

The illus rations show the growth obtainable in the Rakwana
District, where the elevation above sea-level varies from 700
to 900 feet, and the rainfall from 95 to 110 inches. One figure
shows a rubber clearing planted from stumps in June, 1904,
the plants being 17 months old at the time the photograph
was taken, and varying in height between 12 to 20 feet. Another
figure shows trees wliich have been obtained by planting ^ two-
year-old stumps in 1899, the trees being about six years old
at the time the photograph was taksn.

In the Upper Ambagamuwa District, where the rainfall is very
heav^y. Para rubber trees are being tapped and planting operations
continued, though the elevation in sucli a wet district is thought
by many to be near the maximum. About 800 acres were planted
early in 1900, and some of the plants now show satisfactory growth

KURUNEGALA 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
fo lowing figures : —

Mechanical Composition.

Per cent.

Fine soil passing 90 mesh

17 to 35

Fine soil passing 60 niesli . . *.

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;

Organic matter and combined water

4 to 8

Lime

0-1 to 0-35

Magnesia

0-1 to 0-45

Potash

0-08 to 0-18

'Phosphoric acid

0-02 to 0-04

Nitrogen

0-08 to 0-11

During 1905 Para rubber has been largely planted, and a total
estimate of about 4,000 acres for the year 1906 was considered to be
below the probable area for this district.

PARA RUBBER

Passara District.
According to tlie Passara District Association, ni their report
for 1905, large areas in Moneragalla and the lower elevations of
Madulsima and Passara were planted in rubber during the year,
audit was estimated that over 11,000 additional acres would be
opened within a short time. 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 a e said to be such as to
allow of the cultivation of Para rubber up to an elevation of 2,900
feet. Til? illustrations given elsewhere show Para rubber at an
elevation of 2,600 feet on Passara Group Estate, Passara, where
trees varying in age from 7 to 13 years have given 2 lb. of rubber
each during 1905.

" 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 of moisture is about 2i. The chemical analyses
show the presence of from 7 to 11 per cent, of organic matter, 0*1
to 0" 15 per cent, of nitrogen, 0"06 to 0" 1 per cent, of lime, 0*07 to
0*13 per cent, of magnesia, 0'05 to 0*08 per cent, cf potash, and
from 0'03 to 0*04 per cent, of phosphoric acid."

Soils in the West Indies and America.
According to Hart, the following are types of good and inferior
cacao soils as determined in the Government Laboratory, British
Guiana ; they should be well suited for Para rubber : —

i "^.^ Good Cacao Soils.

Deme-

Gre-

St.

Tri-

Nicara-

Suri-

rara.

nada.

Vinceut

nidad.

gua.

nam.

Organic matter and com-

bined water ...

9-031

10-442

3-046

3-768

10-815

15-452

Phosphoric anhydride

0-087

0-184

0-114

0-084

0-293

0-139

Sulphuric anhydride

0-018

traces

0-055

traces

0-141

0-047

Chlorine

traces

nil

traces

nil

(1-007

traces

Iron peroxide ...
Alumma

4-783

9-485

9-574

3-910

7-000

5-952

9-217

10-024

8-889

2-038

4-717

16-076

Manganese oxide

0-347

0-313

0-435

0-127

0-163

nil

Calcium oxide ...

0-596

2-379

4-981

0-356

2-250

0-495

Calcium carbonate

0-03-2

0-026

nil

Magnesium oxide

0-404

3-367

2-41S

0-495

0-217

1-071

Potassium oxide

0-291

0-343

0-178

0-118

0-619

0-072

Sodium oxide ...

0-208

0-574

0-369

0-278

1-184

0-258

Insohiblo silica & silicateB

74-98G

62-803

69-941

88-826

72-594

59-438

100-000

1 . Containing nitrogen . . .

0-262

0-271

0-205

0-100

0-228

0-306

Water retained by air-dried
soil

6-5

12-4

8-1

1-8

8-0

11-00

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PARA RUBBER. 69

Manuring for increasing the Yield of Latex.

If latex is mainly an excretory or useless product it may appear
doubtful as to wliether manuring will hav^c 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
contam, besides the milk tubes, series of cells which store up food,
and others du'ectly associated with conduct nig the materials elabo-
rated 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 ex-
ternally ; 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 different countries by examina-
tion of transverse sections of the trees, and indirectly to form some
idea of the development of tbft 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 foHage,tlie 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 concluded 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 in-
creased in quantity, and there will be a larger number of cells avail-
able for transformation into laticiferous tubes. Any manure which
affects the growth of the leaves or the wood must have a correspond-
ing effect on the cortical tissues. The main object in manuring
Para rubber 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 manming 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 Para rubber.

The analyses of various parts of the Para rubber plant, given
elsewhere, should be carefully considered when mixtures of artificial
rubber manures are being compounded.

70 PARA RUBBER.

Forest Vegetation and Soil Improvements.

It must be remembered that Para rubber trees form a forest
vegetation, and that thoy will grow well in relatively inferior soils
providing there is a fair balance of plant food and that the climatic
conditions are favourable. 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 Para 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 Para Rubber Leaves.

The manurial value of the leaves from Para rubber trees cannot
be doubted when it is remembered that the material, dried at 100'' C,
contains I 12 per cent, of potash, 3" 44 per cent, of nitrogen, 0'6per
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 ujion the physical and chemical properties of the
soil, but the figures showing the composition of various parts of the
Par.i 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.

Manuring Old and Young Trees.

The method to be adopted in manuring this product is deter-
mined by the age of the trees and the kind of manure used.

Where very soluble inanures such as sodium and potassium
nitrate, ammonium sulphate, potassium chloride or sulphate, and
similar compounds are used, tliey should be mixed with dry earth and
broadcasted over the area where the young rootlets are actively grow-
ing. 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 sihould be
taken not to destroy many of the rootlets. Decaying rootlets may
encourage ants and fungi which often prove troublesome on
Eastern estates.

Where cattle manure, green manure, leaf-mould, or bulky artifi-
cial manure are used on rubber estates a slightly dififerent method can

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PARA RUBBER. 71

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 tlie 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 Para rubber tree
grow at a fairly rapid rate in good free soil, and can bo easily
observed ; the manure should be applied at a distance just
within reach of the last- formed rootlets. Around each newly-phinted
tree a shallow trench can be dug, about 12 inclies wide and gradually
increasing in depth from the tree outwards to a maximmn depth of six
to ten inches. The manure can then be mixed with part of the soil,
returned to tiie 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.
The accompanying illustration shows the system applied to young
plants. In this instance the leaves of crotalaria, dadaps, and
groundnuts were buried in the trenches after mixing with lime
and soil. The Para rubber plants were only six months old and
the trenches 6 to 9 inches from the stems. 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 undisturbed.

Results of Manueing Experiments.

As previously po^^ted* out I have been placed in possession
of the results of several manurial experiments, in which (a) green
manure and lime, (b) cattle manure and lime, (c) cattle manure,
lime, and artificial manures, and (d) artificial manures only, have
been used on Eastern rubber estates. The results clearly show
that manuring may bring the trees to a tapjiable size, six to twelve
months before the usual time, a point which nmst appeal to
all interested in developmental companies. The requisite quanti-
ties of the various essential ingredients vary with the age of the
trees and climatic and soil conditions, and only a continuation
of the expeiiments on a large scale can give us accurate information
on this point. It appears to have been proved, liowevcr, that
potash and nitrogen jiroduce 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

India-Rubber Journal, Julyt29, 190';

PARA RUBBER.

not always desirable, and some care must be exercised in fixing the
quantity and nature of artificial nitrogenous manures. Potash,
as might have been anticipated from a consideration of analyses
of parts of the plant, is needed m large quantities, and its appli-
cation has so far been attended with profitable results.

Constituents in Woody Stems and Twigs.
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, as determined by Mr. A. Bruce* : —

Analysis of Parts of a Para Rubber Tree dried at 100°C.

Water

Ash

Lime

Magnesia

Potash

Phosphoric acid

Nitrogen

Fresh
Leaves

Per cent.

, 70
4-69
0-51
0-56
1-72
0-66
3.44

Decayed

fallen
Leaves
Per cent.
60

4-08
1-40
0-89
0-54
0-30
1-92

Fallen
Stalks
Per cent.
60

•18
•80
•30
•64
•15
•84

Wood
Per cent
60

•12
•80
•15
•30
•18
•59

Twigs.
Per cent.
50

•62
•83
•17
•28
•09
•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.

Per cent.

Blood meal

—

10tol4

Groundnut cake

1 to 2 .

1 to 2 . .

1\ to 9

Castor cake

1 to 2 .

1 to 2 . .

6 to 7

Rape cake

1 to 2 .

2 to 3 ..

5 to 6

Nitrate of soda

—

15 to 16

Sulphate of ammonia . .

—

20 i to 21 J

Chloride of potash

57 to 59 .

—

Sulphate of potash

49 to 52 .

—

Precipitated phosphate

of lime

^ —

35 to 40 . .

—

Concentrated super-

phosphate

—

44 to 46 . .

—

Basic slag

—

192 to 21 . .

—

Fish

—

4 to 6 . .

5i to 6i

Bone dust

—

23 to 24 . .

3^ to 4

Nitrate of potash

37 to 40 .

—

ll^to 13

Kainit

13 to 15 .

—

Circular, No. 6, l,c.

Lent bv Maclarcu & Sons.

MANURING YOUNG RUBBER TREES.

PARA RUBBER, ONK YEAR OLD, AND GRKKX MANURING.

THIS ILLUSTRATION INDICATES HOW THE LEAVES OF DADAP

MAY SOMETIMKS BE USED.

PARA RUBBER. 73

Green Manurng for Para Rubber Trees.

It is a fortunate coincidence that the climatic conditions
favourable to the cultivation of Para rubber in the young stage are
identical with those required for the plants of value as green manure.
When estates are planted with rubber alone one must either elect
to allow the soil to be exposed to the sun and rain and to b
thereby impoverished, or decide to protect it by a green crop and
increase the organic matter and mineral constituents for the future
benefit of the growing rubber.

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
that after a good rubber estate is six to eight years old green manur-
ing must practically cease. But during the first few years it is pos-
sible to keep a green cover over those parts of the land not affected
by the rubber plants.

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,
D.C., C. laburnifolia, L., C. incana, L., Cajanus indicus, Spreng,
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. TraiHng 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 full
account of this subject, but the following facts are of interest as
showing the weight of green material obtainable and the composi-
tion of several species : —

Weight of Organic Time between Sowing
Namo of Plant. Matter per Acre. and Uiirooting.

Crotalaria striata . . 20,244 lb. . . Ten montlis

Vigna . . . . 12,092 „ . . Four months

Pondicherry groimdnut . . 4,692 „. .. Five months

( 10)

74 PARA RUBBER.

Composition of Various Green Plants, in the Fresh State.

Nitrogen. Potasli. Phosphoric Acid. Limo

Name of Plant. Per Cent. Per Cent. Per Cent. Per Cent.

Crotalaria striata ..0-7 to 1-0.. 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

It is interesting to work out what the equivalent of 15,0001b.
of green manure of Crotalaria striata is from a purely theoreiical
standpoint.

According to the above analyses it is approximately equal to a
manure of the following composition : —

lb.
Castor cake . . . . . . . . 500

Blood meal .. .. .. ..500

Nitrate of soda . . . . . . 140

Basic slag .. .. .. ..115

Potassium siilphate . . . . . . 140

If the whole of the material is to be used, it should be buried with
lime or basic slag around the trees or fo:ked 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.

An illustration is here given to show the characters of C. striata,
when only six months old . The young rubber, a year old, is just
showing above the Crotalaria ; the latter covers nearly the whole
of the ground and tends to check the growth of weeds

Tree Forms.

The best tree forms to use for green manure are Dadaps (Erythrina
species) and Albizzia moluccana. Dadaps can be propagated from
cuttings ; in some districts they will give a very large amount of organ-
ic 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 practicaUy impossible. They should be lopped or

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PARA RUBBER. tS

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 i by S feet apart in July, 1904

lb.

November, 1904 .. .. 791

Doccmb'u- ,, .. ... 9Qli

March 1905 .. .. 1,935"

April ,, .. .. 1,444^

May ,, .. .. 2,255

Juno ,, .. .. 2,240

July ,, .. .. 2,180 (

August ,, .. .. 3,058

Septoinbor ,, .. .. 1,569|

November ,, — . , 2, 104 J

December ,, — .. 1,653^

Tota .. 20,198i

These experiments show that Dadap cuttings may produce over
1 1 ,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 0*8 of nitrogen, 0-148 of potash,
0*08 of phosphoric acid and 0"197 of lime.

Aleizzia.

Albizzia moluccana is one of the quickest-growing trees known,
but it is not easily propagated from cuttings. The woody tissues pre-
ponderate, 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 Para rubber trees, the branches and
fohage 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 Para rubber estate for the purpose of checking the
spread of disease, the possibility 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.

1Q parA rubber.

Geeen Manuking in Malaya.
Ridley maintains that in the Straits and F.M.S., manuring the
trees by the trenching system or the interplanting of Para rubber
trees with Badaps is not to be recommended as it mvohes an
interference or destruction of the roots and cutting out at a later
date. He is of the ojiinion that green manuring in the Straits and
F.M.S., should be done only with herbaceous plants, and these
should be merely cut and thrown on the ground and not dug m.

SCULFER'S TAPPING KNIFE-

MILLER'S TAPPING KNIFE

SRINIVASAGAMS TAPPING KNIFE-

CHAPTER VI.
TAPPING OPERATIONS AND IMPLEMENTS,

Importance of tapping operations — The tliicknoss of the bark tissue ,
and shedding of dried latex tubes — Effect of bad tapping illus-
trated— Tapping knives — Requisites of a good tapping knife —
Keconimendations of judges at the Ceylon Rubber Exhibition^
Clean cuts and scraping — Protection of the canabium — Paring
from right to left and left to right — Minimum excision of cortex
and bark — Paring and pricking — Patent tapping knives — Native
implement — Carpenter's chisel — Surgical scrapers and planes —
Beta knife — Golledge's knife, construction and illustration — •
HoUoway's knives — Mackenzie's knife — Collet's knife — Brown
& Co.'s knives, construction and illustrations — Eastern Produce
and Estates Co.'s knife — Bowman's and Northway's three knives,
construction, method of use, and illustrations — Dixon's knife,
construction, improvements, and illustration — Macadam's Comb
pricker — Macadam-Miller paring knife — Miller's knife — The
Farrier's knife — Pask- Holloway knife — The "Secure" knife — •
Kerkchove's knife — Walker's Combination knife. — "Scorpion"
paring knife — Srinivasagain's knife — Tisdall's Knife — Sculfer's
Tapping knife — Bowinan-Northway knife.

THE question of how to tap Para rubber trees is one which
deserves special consideration and is not outweighed in impor-
tance by even the process of curing or methods of planting this
species. On the methods of tapping depend not only the quality and
(fuantity of the latex and rubber, hut the life and future condition of
the trees

We are concerned with the laticiferous tubes in tlie outer part of
he stems when the trees are ready for tapping.

The thickness of this tissue may vary from i^ 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 Singa-
pore, only 11 years old, possess bark of this thickness. The outer
part to a deptli of |^ inch (3 mm.) does not contain many tubes,
but the inner part has a large number, and from the inner -^l to
■f^ inch the milk mainly flows. The tubes in the outer part dry
up and are regularly shed with the outer bark tissues.

78 PAtlA RUBBiiR.

When the original cortex has been removed new tissue is produc-
ed, mainly from above downwards and witliin outwards, and in this
the latex tubes aiise dc novo as in tlie original material. It is impor-
tant 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 milk-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 H
lb. of rubber per tree, per year, from eleven-year-old trees. It has
been stated that the yields possible in the near future may, if present
prices are maintained, be such as to allow one to consider the
contingency of re-planting every twelfth year. The yield obtained
in some parts of Ceylon 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 j)resent knowledge, be accurately
forecasted and may or may not prove to be detrimental.

Effect of Bad Tapping.

It is more than likely that the tapping implements and methods
of the future will be such as to ensure tliat the minimum, if any, dam-
age is done to the cambium. With all due respect to the inventors
wlio have placed their knives before the public, it may be stated
that the faultless or ideal paring implement has not yet been pro-
duced, though there seems every likelihood tliat it will soon be on
the market. There are still several implements sold and used which
should be classed as dangerous. In order to impress all planters
with the ultimate effect of bad tapping, a couple of photographs are
here reproduced.

In the accompanying illustration the upper figure shows a part
of a large tree witli the bark and part of the wood removed.
The large approximately V-shaped hollow in the exposed section is
due to the decay of the wood,w]nch occurred internally to a depth of
several inches, and was caused originally by making a large V wound
that scraped below the cambium into the timber all along the in-
cision. The lower figure on the same Plate shows a section of the
wood with part of the bark and outer tissues removed. The wood was,
with the original tapping, considerably damaged, and several years
after the injury was made the parts above it were found to be very
hard and to give very little latex : the wood was permanently
damaged. In this 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 made. The black V-shaped lines in the exposed wood show
the direction and extent of the old Vicuts ; these penetrated to the

EFFECT OF BAD TAPPING ON THE WOOD-

SHOWrXrt DECAY OK I.VTKKXAI. WoOll WIIKHK INJrHKI) 1!V TAI'P[.\(;.

;■

)^sy

- J

f</

Photos by M. Kcliuay Bambcr.

(a) OUTKR wood REMOVlCn ; (k) DAKK V LINKS INDICATING THE DECOMPOSITTON

OF THE WOOD.

THE "SECURE" TAPPING
KNIFE-

WALKER'S PARA COMBINATION
KNIFE
A. These Blades are detachable.

PARA RUBBER. 7ft

cambium. In all such cases tlie decomposition of a vutal part of the
tree has been set up, and the vigour and longevity of the tree appreci-
ably affected. I have seen several other malformations produced by
damaging the wood while tapping ; often the areas become very
"warty" and present a series of ver}^ 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. Sucli knobs and
scars are not due to "canker,'" and the establishment of a smooth
surface on such trees without cutting into the wood is practically
an impossibility.

The tapping of irregular surfaces requires special consideration ;
but it may be stated that in no case should the woody protuberances
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 tap-
ping (see next chapter) can often be adopted with advantage.

Tapping Knives

The various methods of tapping now in vogue are often associa-
ted with the use of a particular knife or series of knives, and it is
therefore necessary to first consider the knives commonly used and
the general requirements of such implements.

Requisites of a Good Tapping Knife.

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 Exhi-
bition, the following points were considered in connection with
the tapping knives exhibited : —

1. Thinness of paring : — Under this head the judges decided
that the miiformity cf tlie 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. Convejiience ami facility in operation : — In this group the
points considered related to the muscular effort required ; visibilitv
of cut during tapping operations ; capablity 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

80 PARA RUBBER

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 would not 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 in-
cision and subsequent paring operations ; those used in the latter
processes are frequently made so that they can be adjusted before-
hand, or they are protected by a fixed or detachable blade. A glance
at the various photographs and diagrams will show the appliances
referred to. The effect of bad tapping is shown elsewhere. It is a
great advantage if the cutting parts can be adjusted with ease and
replaced witliout great expense

A third consideration, which should not be lost sight of, is tliat
the knife should be one which can be used in cutting from left to riglit
and right to left from above downwards. Several illustrations
show knives which can be so used, and also from below upwards if
desired. This is a necessary qualification in all tapping methods
except the right-hand half-herring-bone and spiral systems.

A fourth point, which has obviously received attention in the
knives recently put on the market, is tliat 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 tapping area depends upon
this operation, and at the present time there are knives capable of
demolishing 12 inclies of bark in three montlis, and otliers which will
not use up tlie same quantity of tissue in two or tluee years. The
very narrow cutting margins of several knives are specially devised
for paring away very thin sliavings of the bark.

The introduction of pricking instruments for cutting the laticif-
erous tubes in the wound area, though duplicating the tools, is very
useful; generally the dupHcation of the tools required to make the

•3diN>i ONiddvx s.iivasii

CAMERON BROS' "SCORPION' TAPPING KNIFE

PARA RUBBER. 81

first and pubsequent incisions is undesirable, and in several instru-
ments the power of adjustment is such as to allow all the operations
to be carried out by means of one knife onlj\

Paring and Pricking.
The amount of cortical or bark tissue removed by one par-
ing operation is sometimes surprisingly larg3. The average cooly
will excise the lower surface until a large number of white globules of
latex have appeared, when by tlie use of other implements the latex
tubes might have been tapped without excising any cortical cells at
till. It has been asserted that since the mo5t careful method
may only allow one to tap the whole of the surface from the base up
to six feet in two to three years, the care advocated is not necessary
when large aci-eages have to be tapped. But the necessity for tap-
ping every tree on a large plantation is no excuse for excising the
cortical tissues in a wasteful manner. The best results will accom-
pany 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 mate-
rial thus removed. This is correct especially when large quantities of
bark are cut away, but the greater part of the rubber can, by proper
paring and pricking, be removed without great waste of tissues.

Furthermore, it should be distinctly borne in mind that the re-
moval 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.

Patent Tapping Knives.
The native collectors of rubber in the uncultivated forests o^
Brazil use an axe-like implement, with which a heavy blow can be in-
flicted and all the tissues from the bark to the cambium be cut in one
stroke. At the present time Ceylon is taking a very active interest
in inventing and improving tapping knives for use in obtaining
latex from Para 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 superseded
by more useful tools. Parkin carried out experiments to see " whe-
ther 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

(11)

82 PARA RUBBER.

recommended a wedge-shaped chisel with a thickness of Vo to ] incli,
at a distance of h inch from the cutting edge ; the breadth of the
chisel varied from 1 to IJ, in.

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 thicknesses
of the bark of different trees and so prevent its damaging the wood
of the tree.

CtOlledge's Knife.

In the accompanying illustration it will be seen that this
knife consists of a flat piece of steel provided at the end
with a short sharp bevelled V and a cutting groove along the sides.
The knife can be used for making cuts from above downwards, be-
1 ow upwards, and from left to right or right to left. It can be used to
make the original incision and during subsequent paring operations.
The illustration showing the herring-bone system of tapping,
at Gikiyanakanda, indicates the good work done by means of
this knife.

Holloway's Knives.

The Holloway tapping tool is an improved V knife pro-
vided with movable blades ; the V head is fastened to th(^ handle by
two small screws and nuts, and the blade wJien worn down is easily
replaced.

Holloway has brought out another knife which is essentially pro-
vided 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 pro\T[ded with a flange at either side at right angles to the base, and
all parts lan 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 havin g

jutting edges on three sides. The cutting surfaces ai-e in one piece

and movable; by an ingenious screw arrangement the depth of the

"utting edges can be ad justed according to requirements by two side

guards. The knife can be used for tapping from left to right or right

l^-^ u

Section CO

GOLLEDQE'S KNIFE

?o-

THE "SAFETY- TAPPING KNIFF-

mr Will'

Lent bv Brmvn & Co.

THE PARA CHISEL.

PARA RUBBER. 83

to loft. When the incision is so broad that the guard on the uppoi-
side of the knife does not rest against the ])ark on the top side of the
cut, the upper guard can be lowered so as to come in contact witli
the excised area, along which it rubs during paring operations.

Collet's Knife.

M. Collet recently exhibited a new tapping knife whicli I am in-
formed has been patented in Belgium. It is made entirely of metal :
running down tlie liandle, 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, ana nas 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 Knife and Chisel.

The two instruments indicated are obtainable, from Messrs.
Brown & Co. , Colombo. The " tapping knife " is designed for making
the first incisions in rubber trees, wlien tlie paring process is intend-
ed to be carried out in tlie subsequent tapping rounds. It is con-
structed to make incisions on the left and riglit 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 ]:»aring. The " Para Chisel "
is a tool for re-opening the original incision in such a manner as to
renew the flow of latex witli the minimum loss of bark tissue.
It is first adjusted to cut to the required deptli, 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. The
accompanying illustration shows the construction of the
important parts.

An Implement for Tapping Rubber Trees.

The Eastern Produce and Estates Company are responsible for
a knife, already largely used on many estates in Ceylon. The
patentee claims that it is a simple knife and one which can be econ-
omically used over large acreages of rubber. It consists of a wood-
en liandle 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 tissue to see if the latex is abundant.
The cuttini;' 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 tlie apex. This knife was one of the first to be

84 PARA RUBBER.

placed on the market, and a detailed account of it is given in the
India-Rubber Journal of February, 1904.

Bowman's and Northway's Knives.

These knives have been continually used in the experiments
at Peradeniya and Henaratgoda, and in response to suggestions
the originals have been slightly modified in order to be of use in
any of the numerous systems of tapping, and to still further econo-
mize in the removal of the cortical tissues. There are three knives
in all : No. 1 for making the original groove, No. 2 for re-opening
the lower surface of tlie wound, and No. 3 for i^ricking the latex
tubes in tlie area of the wound response without removal of any
cortical tissue. These knives are shown in the accompanying illus-
trations.

Knife No. 1 is provided with a two-edged guide, which on press-
ing 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
cambivm are very thin indeed; it is therefore advisable to mark lightly
with No. 1 and reach the correct depth gradually with a few tappings
with No. 2 in the manner described below for cutting deeper

Knife No. 2 in its improved form is very ingenious. The cut-
ting 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 inserted
there are two small cutting edges available, one to use when cut-
ting from right to left and one for use from left to right. Several
of the No. 2 knives are only provided 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 sub-
stance 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.

•i
^

P/ioto by D. L. GooiHifurJaiic.
BOWMANS AND NORTHWAYS KNIVES-

DIXONS TAPPING KNIFE-

PARA RUBBER. 86

Tlie basal cutting surface of tliis knife has now l)een 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 milk vessels which liave
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 wlien tapping
trees of widely different ages. It can be used alternately witli No.2
knife, though in tlie 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. The knives have elicited
the admiration of many rubber planters wlio have adopted the prick-
ing and paring method. Tlie value of a pricking instrument does
not appear to be fully appreciated by many, but when it is pointed
out that by means of sucli an implement the excised area in three
months' work, tapping twice per week, is less than one inch, its
usefulness cannot be doubted.

Dixon's Knife.
This consists of a grooved open knife blade, capable of being ad-
justed 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 there-
fore capable of being replaced when worn out. The base is pro-
vided witli a pricker for determining bark thicknesses, removing
scrap rubber from the cuts and 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. By favour of Mr. Dixon the accom-
panying illustration is here reproduced.

Macadam's Comb Pricker.
Another type of pricking instrument has been introduced by
Mr. Macadam of Culloden estate, Kalutara ; this is worthy of k
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.

86 PARA RUBBER

long and the blade is lU cm. in length, so that a tapping line one
foot in length (30 J cm.) could be pricked in three operations. The
blade sHdes along "two side grooves and is provided with two project-
ing pieces of metal for handling during adjustment. The blade can
be pushed outwards or drawn inwards, thus allowing only a definite
lenf^th 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;
drao-ging of the bark cells is therefore almost impossible. In
other prickers the tapper naturally draws or pushes the instrument
in a particular direction, and the unavoidable dragging may result
in a clogging of individual milk 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 obtain-
able and the required pressure 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 oi- 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,
substantial steel head firmly attached below to a wooden handle.
The Icnife is constructed "so that the operator may cut from
lialit to left or left to light, from above downwards or below
upwards. The essential ])arts 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 C'eylon Rubber Exhibition, 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 thimiest strips of bark.

Sculfer's Knife.
A cheap and durable knife has been brought out by Mr. H.(l.
Sculfer. The knife is lifted with a guide which allows only a
small paring to be taken off at each cut, also stopping any danger

MACADAMS COMB PRICKER-

MACADAMVIILLER KNIFE

PARA RUBBER. 87

of cutting tlie cambiuiu. It will cut cither right or left, nulling or
pushing, and is easily sharpened and there is no possibility of
the knife choking.

' 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 said to be largely used on
sonie estates in Malaya and to give 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
will bj^ the coolies, this form should appeal.

Pask-Holloway Knife

This knife is designed to cut thin sections of bark during tapj^mg
operations. The rectangular-shaped piece of metal at the end
of the blade is almost blocked so that ver}^ narrow cutting edges
lemain 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 strongty-made knife and can be used 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.

Messrs. Thomas Newey and Sons have brought out a tapping
kinfe which is strongly made and serviceable. The knife will cut
in either direction, pulling or pushing, and can be adjusted accord-
ing to the thickness of the bark to be tapped. The blade is joined
to a circular disc by means of a bolt and fitted so as to rotate in a
slide to any angle required. The circular base and disc are toothed
and lock securely in any position. The pin has a s(juare shoulder
to prevent turning, and the shank is riveted in the handle.

Kerckhove's Knife.
(i. Van den Kerckhove has patented a knife, which he states is
speciaU}- adapted for tappuig rubber trees and vines. The knife
consists of a steel spike, with handle; at the end of the spike,
which is slightly curved, is a jjlate with a screw and three
moveable blades with oblique edges. These blades can be regulated
according to the thickness of the bark to bo cut ; the blades can
be used combined or singly, according to requirements.

Walker's Combination Knife.
An ingenious knife has been recently brought forward by Mr. H.
E. Walker, provided with parmg section and rotatory pricker.
The claims of the inventor are as follows : —

(1 ). The combination of shavuig blade and pricking spur allowK
the operator to use either ^a) blade and spur ui the same operation,

88 PARA RUBBER.

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 dqep ; (3) the spur
may be easily adjusted by means of the slot in which it is fixed and
made to penetrate to varying depths, or withdrawn from use,
without removal of any part of the instrument ; (4) the form of
the sj)ur is such that during use it will onh^ prick 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 303 lineal feet in one hour, on trees
25 feet apart carrying 2 feet of tapping line each.

The cutting parts have been designed to allow the operator
tc pare thick bark shavings l/18th 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. This knife is
illustrated elsewhere.

Srinivasagam's Knife.

This knife is designed to make the original incisions, to pare off
thm shavings, to channel the side of the tapping cut, and to clean
the treei; 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.

Bowman- North way Knife.

A new knife has been recently brought forward by Messrs.
Bowman and Xortiiway of Ceylon and has been fully described and
illustrated 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 sharp-
ened at both ends. Guide pins are provided to regulate the depth
ot 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.

Lent by Maclaren & Sons.
THE BOWMANNORTHWAY "Sl^PkEX"
KNIFE IN USE.

Plwto bv C. H. Kerr.

Lent by G.H. CoUedge.
PARA RUBBER IN CEYLON
Kam'taka Disthk t.
Taimmno Opi;kation.s at Giki va.nakanua.

CHAPTER VII.
now TO TAP PABA EJJBBER TREES.

Afethods of tappinp; Para rubber treos — Methods of native collectors in
Brazil and on the Gold Coast — Observations of Jumelle and
Bonnecliavix — Modern methods — Single oblique cuts, illustrated
— V incisions, illustration sliowing a tree after ten weeks' tapping
— Limited area — Herring-bone system — Photographs of trees in
Ceylon tapped on the hen^mg-bone system — The zig-zag method
and its use — Spiral curves — F. Crosbie Roles on the spiral method,
yields and estimates — Results of the spiral sj-stem in parts of Ceylon
— Collecting and storing of latex — Bury's protector — Centralizing
tlie latex from many trees. — Drip-tins, their construction and
action, illustrated — Keeping the latex liquid and settling tanks
— Method of marking the trees for tapping — Collecting tins.

Methods of T.apping.

The best method of tapping is that which extracts the maximum
amount of latex from the tree with removal of the minimum quan-
tity 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 by a process of
perforation and decomposition at a later stage. 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 be tapped to
the same advantage as previously.

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 tlie best system on sucli trees is difficult
and often impossible.

Methods of Native CoLiiECTORS in Brazil.
The felling of the wild trees and the ringing of the bark and
cortex in order to collect the milk aie now rarely practised by native
collectors. The latex is usually collected from the trees while
standinvT, and in the Amazon districts an upward incision is made
in the bark by means of a small axe, and a cup is then placed
beneath each cut.

( 12)

90 PARA RUBBER.

According to Jumelle,* M. Bonnechaux has investigated many
of the BraziUan forests, and the information regarding the rubber
from Hevea species wliich that explorer has compiled is of interest
to all cultivators of Para rubber. The collection of caoutchouc
is mainly from species of Hevea, but certain species of Sapium are
credited as yielding good latex which is frequently mixed with that
from the Hevea trees.

According to Bonnechaux, the Hevea trees are to be found in
groups of from 120 to 180 wild trees, mainly along the courses of
the rivers. When they are numerous the average distance between
two Hevea trees is about 30 steps; when less abundant, about 50
steps ; and where more widely scattered the collection of caoutchouc
is considered to be too difficult and laborious. The trees on one
group were measured by Bonnechaux and varied from 0 • 25 to 0 • 90
metre in diameter. (1 metre^about 39^ inches).

Collecting operations are, according to the above authority, com-
menced in July when the rainy season is drawing to a close and
when the rivers are low, and are continued until February. Tapping
is commenced in the morning immediately after sunrise, the men
making their incisions from below to a height of about six to seven
feet with axes ; receptacles are fixed in the bark and the latex
allowed to run into them, while the tapping of other trees is con-
tinued. In other parts of Brazil the latex is collected by punc-
turing the bark and conducting the latex by means of the leaf stalks
of M auriiia flexuosa , Mart., to the apex of a V, where a receptacle
is placed. The receptacles have a capacity of 10 to 20 centilitres,
three or four being used for trees having a diameter of 50 cm.,
(19| inches). All the trees in one group are tapped on the same day,
the men spending very little time in making the incisions and fixing
the receptacles. The latex is finally poured and stored in a vessel
made to hold from 4 to 8 litres. The men on the following day
make new incisions below the old ones and continue the operation
for as long as convenient.

Method in the Gold Coast.

In the Gold Coast a system rather similar to the full herring-
bone is often used, a series of small transverse channels opening
into a perpendicular one at the base of which the latex is collected.

Modern Methods of Tapping.

At the present time the various methods of tapping Para rubber
trees may be roughly described as (a) single oblique lines ; (6)
V-shaped incisions ; (c) single cuts with a vertical channel join-
ing them : when the cuts are on one side only of the vertical line,
the system is often termed the half -herring-bone, and when on both

* Les Plantes Cmjutchouc et Gutta, by Henri Jumelle, Paris, 1903.

A B

Photo by H. F. Macmillan.
THE FULL SPIRAL SYSTEM.

A.— THK FIRST INCISION. H.— AKTKR THK TRKK HAS GIVEN '1 LB. DRY RV'BBER.

PARA RUBBER. 91

sides the full herring-bone system ; (d) spiral curves. Tliere 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 as extra-
vagant as it is unnecessary in most cases. 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. Each oblique
cut may be from one to six or more inches in length, but a distance
of nearly one foot apart should be allowed. 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 con-
siderable length.

In this system collecting cups can be placed at the base'of each
incision, but an invention for conducting the latex from all the in-
cisions to a central basal coil has been brought forward, which, if
adopted, might add to the value of this system of tapping.

V Incisions.

The V incision is nothing more or less than a duphcated or double
obhque 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 obtain-
able from such incisions is generally, but not always, about double
that obtained from a single oblique cut, and having one centre for
two incisions seems to be one of the greatest advantages of tliis sys-
tem. 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 has been suggested that the reason why the quantity of latex
obtainable is not double that from a single oblique hne is because
the lines are very close to one another and may draw on the same
system of laticiferous tubes, a conclusion which is warranted by the

92 PARA RUBBER.

results of many experiments in varioua 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 di-ying and tapping from the apex of the V upwards.

It cannot be doubted that in a system of small oblique or V
cuts a considerable amount of labour is involved in fixing and ad-
justing a very large number of collecting tins at the base of each in-
cision, 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.

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 milk after two months' tapping becomes very poor. The
photograph reproduced on the accompanymg Plate shows the V cuts
after tapping for ten weeks every alternate day. There was, at the
time the photograph was taken, still plenty of space between the ad-
jacent incisions, but the flow of milk was too small to warrant fur-
ther tapping. This method obviously cannot be carried out for the
same length of time as the half or full spiral curves, because the
obHque cuts sooner or later interfere with one another and draw on
the same hmited 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.

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 advantage in connection with the tapping of Para nibber trees.

Herring-Bone System.

This consists of a series of short, parallel, obhque 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 somewhat diagramatic illustrations sliow both systems at the
beginning. The vertical channel may vary from 1 to 6 feet in
length, and is usually sufficiently wide to conduct the latex from a
dozen oblique cuts ; the tin placed at the base is the only receptacle
for the latex. The advantage of this system lies in the minimum
labour required for collecting operations, but there arc many reason-
able objections against the waste of tissue which occurs when a ver-
tical channel of considerable depth and width is made. Though
it is considered to be more drastic than the foregoing method, this
system is in use on several estates in Ceylon, and has at times been
adopted with success by planters and officials in the Malay
Peninsula, India, and Africa.

Photo by H. F. Macmillun.
V. TAPPING.

A TREE AFTEIl IT HAS GIVEN 2 LB. OF DRY RL'BBER.

PARA RUBBER. 9:J

After the original oblique incisions have heen made they aro
re-opened by paring away tlie lower surface, this operation being
continued until the whole of the tissue between the lines is used up.
An}' of the knives described may ho used for tiiese 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 groove
in the bark. Experiments have been made with conducting channels
composed of clay, the inner ridge being left open at the base of the in-
cision and the outer one continuous from top to l)ottom 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 recom-
mended.

The illustrations given here and elsewhere show trees which have
been tapped on this system in parts of Ceylon and Malacca.

According to Ridley the tree has, for tapping purposes on the
herring-bone system, four sides, and may be tapped along one side
only during each year so that operations will be recommenced on the
tapping area of 1904 in 1909. This is a very gentle method, and has
much in its favour ; it can be used to advantage when tapping
according to exposure to the sun is adopted.

The zig-zag system of tapping consists of a downward line join-
ing two oblique cuts, on opposite sides but at different levels, and so
arranged that the latex is collected at the base of the lowest incision.
Tliis 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.

It has been 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.

Northway's and Bowman's Spiral Curves.

A third method which, on account of the good yields obtained,
attracted considerable attention recently 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 num-
ber of spiral cuts is determined by the circumference of the tree, there
being usually one curve for every girth of 12 to 18 inches at the top
of the tapping area. In this metliod of tapping a series of special
knives was used ; these ensured the minimum waste of tissue

* M. Henri Lecomte, Journal d' Agriculture Tropicale, April, 1902.

94 PARA RUBBER.

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 Pera-
deniya, and was continued in some districts until a total of
16 lb. per tree was obtained in twelve months, a detailed
description is here given. The illustrations sliow the stages from
the beginning to the end of the first cortical stripping. Spiral
tapping is not, however, largely practised ui the East.

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 the best system to adopt
when it is intended to kill out intermediate trees on estates which
are too densely planted, and can in such instances be carried out on
young trees. The results obtained by this system on lO-to-30-year-
old trees at Henaratgoda and Peradeniya appear to justify
its adoption on old Para trees, providing the operation is carried out
carefully and slowly. The bark on the old trees at the places men-
tioned was removed at the rate of only one inch in three months,
and further improvements in the same direction are still possible.

The Spiral System at Peradeniya and Henaratgoda.

The spiral system was, in addition to all the foregoing methods ,
tried at Peradeniya and Henaratgoda with fairly satisfactory
results. It will be seen that the yields obtained at Peradeniya were
not as large as those reported from other parts of the island;
the results at Henaratgoda were good considering the number of times
the trees were tapped. The results obtained by different sys-
tems at Henaratgoda are given elsewhere, and from them the reader
may make his own deductions. The herring-bone and spiral systems
allow one to systematically tap the tree from above downwards for one
or more years, and to repeat the same operation when convenient.
Any system of tapping, which allows the cooly to go over the whole
of the bark tissues on a regular plan, is to be preferred to the old V
or single short cuts.

I am indebted to Mr. F. Crosbie Roles, Editor of the Times of
Ceylon, Colombo, for tlie following description of tlie method
as carried out on a well-known rubber property in the south of the
island : —

The Method of Cutting.

" Tlie first cuts are made each a foot above the other, and in the
case of a tree 18 inches in circumference tlie groove would go nearly
round the stem. For trees 30 inches in circumference two lines of
cups on opposite sides of the tree would be required, and a tree 54
inches in girth would take three lines of cups. The first cut is made
with a knife used nmch like a plane ; and the second knife is used
thereafter day by day for paring off the edge of the groove orighially

THE HERRING-BONE SYSTEM- ^''''' '' "' ""• ^^'"^''^^»'

(A) HALF HEUKINGBONE ; (b) FULL HERRING-BONE.

PAHA RITBBER, 95

made. One month's lappinp; with tlie original knives made the
groove two inches wide, so that tlie whole bark area would be cut
away in the course of tiie year's work, assuming tliat the tapping
were carried on throughout the year in alternate months. The
cutting face of No. 2 knife, however, has been reduced to the 16th of
an inch. This reduces the bark area cut away in a month from two
inches to one inch. A third instrument has been invented for use
in this process. It is in the form of a circular pricking instrument,
which is used to penetrate to tlie cambium at the edge of the pre-
vious cut. This is done alternately with the cutting, and is
beUeved to free the inner bark from any accumulation of latex.

The Yield from such a Method.

"This method was systematically begun in October, 1904, and
the group of trees has since averaged over 2 lb. of rubber per tree for
each month's tapping, and those trees whicii have been tapped
hardest have produced 16 lb. each in twelve months. Although
these trees, like the rest, were tapped in alternate months at first
with rest in November and January, they were continously tapped
from February, right through the drought, up to early in .June.
Then it was found that tlie yield was falhng off, and they were
rested for some time. Tapping was recommenced in September.
None of them show signs of drooping, and as further token that new
and handsome figures in Ceylon yields are not confined to a few
trees, records were produced which showed that the whole of the
255 trees on the estate of tappable age had yielded an average of
41b. per tree in the eight months, without the trees being harassed.
A platform is to be erected round some of the trees for tapping high-
er up ; and an average jaeld of .3 lb. per tree is expected at from 6
feet to 10 feet from the ground."

The illustrations show at a glance the method adopted ; the
results obtained, both by the inventor and at Peradeniya, have
arrested considerable attention among all cultivators of Para rubber,
though the system is by no means extensively adopted at the
present time.

The Collecting and Storing of the Latex.

Having briefly indicated the general principles of tapping
implements and operations, it now remains for us to consider the
more special contrivances and methods adopted in the process of
collecting the latex.

A Protector.

Mr. A. H. Bury, Ceylon, has devised an apparatus to protect the
collecting cups during tapping operations from rain and mechanical
impurities. " The protector is to consist of a zinc collar 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

96 PARA RUBBER.

it and allow it to drain oil" tlie roof over the latex cup. It will
also fasten witli 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 collar
being attached at various times to trees of different girth."*

Centralizing the Latex from many Trees.

On most estates the latex is collected from sej^arate incisions on
a tree or from individual trees, an arrangement which will require a
v^ery large labour force when large acreages come into bearing. If the
trees are regularly planted and the slope of the ground is favourable ,
there seems to be no reason why a much simpler arrangement
for collecting the latex from all or a large number of the tvem should
not 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, a method
which affects the question of labour on large estates. 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 invention is applicable to the
V, single oblique, half and full spiral methods of tapping, and in
part is applicable to other systems.

Numerous drip spouts made of suitable material are fixed to the
base of each incision ; the spouts are grooved and of unequal length
and are so positioned on the stem as to allow the latex to drip from the
upper into the lower spout and finally into a basal coil at the bottom of
the tree. The basil coil is grooved and goes completely round the stem
at the bottom, and is provided with legs adjusted so as to tilt forward
on one side and so allow the latex to escape at a lip or through a hole
into a receptacle or conducting channel beneath. By these meanfi it
is claimed tliat the latex from a very large number of trees can be
brought to one point, a great advantage in collecting latex from
widely distant trees. The metliod, though ingenious, is not con-
sidered practicable. The accompan3Mng illustration shows the
arrangement of the various parts.

Drip-tins : their Construction and Action.
It is well known to most planters who are tapping Para rubber
trees that the latex as it issues from a newly-made incision may
vary much in consistency, sometimes being very watery and flow-
ing freely, at other times being too thick to trickle along the lines
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

* Ceylon Observer.

PARA RUBBER. 97

being collected except as scrap rubber. Furthermore, the latex
during the periods of drought does not run as freely as when the
moisture conditions are more favourable.

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 and ammonia or water and 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 in-
genious sci'ew arrangement by means of which the drops 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 tiie coagulated substances continue to give forth the
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.

It is certainly an advantage to be able to secure, when
necessary, the latex in such a state that it will remain in a liquid
condition until the formalin or ammonia is driven off. The
accompanying sketches show the essential parts.

The above refers to tlie 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 not largely adopted in the East.

Keeping the Latex Liquid and Settling Tanks,

On small estates where few and widely-scattered trees are being
tapped the planter is often compelled to resort to the production of
rubber on a small scale ; this frequently involves a daily repetition
of the same process and 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.

The latex can be kept in the liquid condition by the addition of
ammonia, formalin, sodium carbonate, or any alkaline chemical
which is r v>adily 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.

(13)

98 PARA RUBBER.

In one invention, patented by Brown, the latex is kept in covered
settling tanks supplied with (1) 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 containing
ammonia is exposed to the air, the reagent 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 Hquid state indefinitely.

Formahn 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 maintains
the latex in an alkaline or neutral state, thereby preventing the
precipitation of the proteid matter. By the use of such reagents
and apparatus a great saving of labour may be effected

The Editor of the India-Rubber Journal has recently reviewed
a translation of a privately circulated French pamphlet, onithe sub-
ject of exporting the latex in a liquid condition in order to allow the
manufacturer to prepare his materials at the first coagulation.

Northway's and Bowman's System of Marking the Trees.

The system consists first in marking out the grooves at the correct
distance and angle they are to be cut during tapping. This is
effected by means of a guide in the shape of a right-angled triangular
l^iece of tin, the side subtending the right angle being 2 ft. in length,
and the other sides 17" by 17". The hypotenuse is the fine 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 hjrpotenuse of
the triangle will 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
tho 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 channels 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

n^ffi

Photo b;i Ivor Etherington.
DOUBLE AND MULTIPLE DRIP-TINS.

"NK DKIHTIX KOH TWO OK MOKK TAJ-l'INM; l.I.VKS.
IlKiH TIN HEIiMANKNT : t(>.\ lircTI-\U STRI.NCi AlU ISTAHI.i;.

PARA RUBBER. 99

yielding capacities, the grooves can be made longer or shorter as
may be found necessary or convenient. One month's tapping
with certain knives would carry the grooves down about one inch
so that tapping on and off, one month at a time, the whole space
between the top and bottom grooves would be covered in the
course of two years' work. The operation is carried on continuously,
so that at the end of each period of two years only the original top
cut would have to be re-tapped, the lower cuts being made into
the sections below when the bark tissues have been completely
renewed.

Mr. Francis Holloway 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 anj^ height
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.

Collecting Tins.

Tin or iron receptacles for collecting the latex are not so good
OS enamelled ones or those made of aluminium, as they are apt to
corrode on exposure and to lead to a discolouration of the rubber,
when the latex contains large quantities of tannin. In all methods,
except the herring-bone and spiral systems, it is necessary to fix
the tins on the trees and therefore to have some sharp point to
press against the bark for fixing. Where the herring-bone or spiral
systems are in vogue, a permanent channel is fixed at the base of
each line and the tins placed on the ground immediately under the
channel ; the latter arrangement is found to be economical.

Tlie advantages and disadvantages^ of the various systems,
and the effect of tapping on the quality of the latex, will bo
discussed later.

— M^S'l'aiE^i^^H-

CHAPTER VIII.
WHERE TO TAP.

OccuxTence of latex in parts of the plant — Rubber frona young parts
of trees — Tapping virgin and wound areas — Wound response and
increased yields at Peradeniya, Java, and the Straits — Interval
between successive tappings and wound response — Arden's results —
Clotting of rubber in convex wound areas — Method of formation of
Para milk tubes — Best yielding areas — Results of experiments from
the base upwards in the Straits and Ceylon — Illustration showing
tapping from 6 to IG feet and base to 50 feet at Henaratgoda —
Yields obtained from various levels at Henaratgoda — I.atex from
liigh parts of old trees — Occiurence of uon-coagualfi,ble latex.

IT is wellknown that in tlie Para rubber tree 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
brandies are such as to render the collection from these areas
uni'emunerative. The more or less successful production of gutta-
percha from leaves led many to anticipate that rubber miglit be
obtainable from the fohage and young twigs of Ilevea hrasilic.nsis.
" The latex in young stems* and leaves does not freely ooze out
and mix with water, but clots where it exudes in little lumps,
which cling to the broken pieces of stem." The rubber from tliese
tissues is adhesive and has less elasticity and strength than the rub-
ber from the trunks of juature 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 market-
able rubber. In practice it is easier to tap the stem from six feet
downwards than any other part, though the erection of stands, scaf-
folding, and the use of ladders and walking stilts for tapping liigher
parts and thick branches have been tried with successful results.
Estates are known where rubber in paying quantities has been obtain
ed from six to twenty feet, but tapping above six feet is not generally
adopted. The fact that a maximum of 10 to over 20 lb. of rubber
per tree has been obtained from the lower part of the stem alone
witliin twelve months from commencing tapping operations makes
it very doubtful whetlier taj^ping of less accessible parts will come
into general force. Tlie strain on the plant to heal the wound
area from six feet downwards is quite as much as it need stand.

* Parkin, h c.

PARA RUBBER. 101

Furthermore, it must bo remembered that the maximum quantity of
hitex and rubber may be ol)tained not so much by tapping virgin
areas as by taking advantage of tlie wound response and pricking
or cutting tlie iaticiferous tubes when they contain tlie maximum
amount of latex.

The Wound Response.
It has been stated that native collectors of Para rubber do
]U)t attempt to gather the latex from the first incisions, and that a
ijuantity capable of being collected is only obtained after two or
more tappings in approximately the same area. It is certainly 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 exjiected
from the original incisions. The first cuts can be deepened as neces-
sity 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 is said to decline if the
wound area is continuously tapped. The first reUable results were
obtained by VVilUs and Parkin, 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 : — ■

Number of Number of . Date of Yield of

Tappings. Incisions. Tapping Latex in c.c.

1st tapping .. 40 .. March 25 .. 61-0

2nd ,, .. 40 .. ,,30^ .. 105-5

3rd ,, .. 40 .. April 6 .. 220-0

4th ,, .. 40 .. „ 12 .. 208-5

5th ,, .. 40 .. „ 15 .. 255-5

6tli ,, .. 40 .. ,,20 .. 290-0

7tl) ,, .. 40 .. ,,25 .. 270-0

8th ,, .. 40 .. May' 1 .. 253-0

9th ,, .. 40 .. „ 6 .. 264-5

10th „ .. 40 .. „ 13 .. 275-0

11th ,, .. 40 .. „ 20 .. 255-0

12th „ .. 40 .. „ 26 .. 262-0

13th „ .. 40 .. June 1 .. 328-0

14th „ .. 40 .. „ 6 .. 449-0

The increase in yield from 01 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. Tlie wound response is not evident
twelve hours after tapping, but within twenty-four to forty-eight
hours it is decidedly obvious. These results suggest the ad visabifity
o' 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 wlien rain
was abundant or only during alternate months, has already given

J 02 PARA RUBBER.

excellent results on a large scale on several estates in Ceylon.
The nature of the origm of the latex tubes in Hevea brasiliensis
accounts, to some extent, for the variation in yields from the same
area; tJie tubes require a certain time to complete their formation,
and for this reason areas which do not yield any latex on parti-
cular days may give abundant flows subsequently, wlien the j)ro-
cesses of j^erf oration and decomposition are sufficiently advanced.

In Java, Haas* has proved that wound response occurs in the
Para trees m that island. He also points out that an increase m
the number of incisions ijicreases the yield of rubber, but not in
the same proportion , and states that an increase of 25 grammes of
lubber per square metre of tapped surface is only obtained after
niore than doubling the number of incisions.

Wound Response in 24 Houks.

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^ oz. wet rubber
60 ,, at intervals of two days ,, 111 ,, ,,

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 outline. In some instances
clots of rubber were found beneath the bulging areas, and from
microscopic examination it was^concluded tliat the convex outline
was due, to some extent, to the abnormal rapid distension of
the cells of the newly-formed tissue ; the coagulated rubber seemed
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's and Northway's pricking instrument gave abundant
flows of latex.

There is a certain amount of reason in tapping any yielding area
of the stem and branches, on account of tlie peculiar manner in which
the latex tubes are produced and their connection with one another.
The tubes in Para rubber are produced by the breaking down of the
j)artition walls of adjacent cells or sacs, and the final tubes may
be very short or long according to the age and the number of par-
tition walls which have been dissolved. The tubes arise dc novo,
and in tapping operations one does not necessarily drain the latex
from all parts of the tree, but very often only from one or two mclies
around the incision, where latex tubes have been formed.

♦Results of experim(Mit»il tappings of Heven Ijrasilionsis, Java, 1900-
1 904, by Dr. W. R. Tronip dc Haas. (YkIq Bulletiix of Htraits & F.M.S.),
August, 1905.

PARA RUBBER.

103

Best Yielding Areas.
Experiments to prove whicli is tlie best carca to tap liave been
carriod out by many observers. Tlie larger flow at the base of tlie
trunk than from higher parts has been noticed by Parkin and
others in Ceylon, by Seaton in India, by Haas in Java, by Arden
in Malaya, as well as by native collectors in the Amazon
valley. It is on account of this tiiat the idea of increasing the lower
tappmg area, by pruning the young plants and retaining a few of the
basal shoots to grow into leaders in after vears, is often recom-
mended, for mstead of one stem there miglit be two or three
available for tapping. If only one stem is retained, it will show a
large increase in circumference.

Results of Experiiments regarding Quality
AND Quantity.

Experiments in Malaya.

The following experimental tappings by Burgess* indicate the
quality of the rubber from different parts of the plants :—

Position of the

Cut.

1. A large root ex-
posed by removal
of some soil. i

2. The main trunk
1-2 feet above
the ground.

3. The trunlc after

forliing 20 feet
above ground.

Natm-e of Cut.

I Percentage of i

Crude Rubber in

Latex. ;

Percentage of

Resin in the

Crude Rubber

Simple three-
inch cut.

Herring-bone

Herring-bone.

43-8
44-4
39-8

2-27
2-12

1-88

It will be noted that the latex from the higher portions of
tne trunk are, in the above experiments, poorer in rubber than
the latex from lower down-at the same time the proportional
amount of resm in the latex appears to decrease."

The following experimentsf indicate that the lower part up to
98 cm (1 cmt. equals to 0-39 inch) yields considerably more rubber
tnan the higher parts : —

Number of

Incisions.

120

100

120

Area tapped.

0 to 60 cm.

60 to 120 cm.

120 to 180 cm.

Yield of Latex

in grammes.

2226-44

1111-09

587-43

* Burgess in Agricultural Bulletin of the Straits & F.M. S., Mav 19 04
t L Hevea Asiatique, M. Collet, ^

104 PARA RUBBER.

These results sliow that tlie maximum yield, 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.

Experiments in Ceylon.

Experiments carried out in Ceylon * strongly support the same
conclusion, and the following are typical examples of the results
obtained : —

Number of a i. j Yield of

T • . Area tapped. -, ,

Incisions. ^ '■ Latex in c.c

26 .. 12 inches from base .. 24-5

.. 36 „ „ .. 18-0

72 „ „ .. 18-5

14 . . At base of trunk . . 30

B •{ 14 . . At 48 inches from base . . 14

14 .. At 108 ,, .. 11-5

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 httle ;
and that above five or six feet the latex exuded falls off very consider-
ably." Experiments in the Straits have sliown 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 wellknown to
])lanters in Ceylon that the quantity of latex obtained at five to six
feet from the ground is httle more than half that at the base of
the trunk ; nevertheless, a yield of over 1 to 3 lb. of rubber, per tree,
is expected on certain estates by ta})ping the area from six to
ten feet above ground. The latex ol)tained from areas twenty
feet from the base is often very sticky and may not jdeld good
rubber, but this is by no means always the case. On some
estates in the Ambalangoda, Kalutara, and Matalc Districts the
old rubber trees are said to give latex of good quality from six
feet upwards.

According to Dr. Haas, the trees in Java gave the largest yield
in their lower parts, and tapping up to a height of P5 metre gave
the best results.

Tapping the Higher Parts of Trees.
Base to 50 feet.
As previously indicated, it is possible to obtain rubber in paying
quantities from parts of the stem above six feet. At Henaratgoda
the trees have really never been cultivated, and many of them,

* Parkin, l. c, pp. 128 and 131.

HIGH TAPPING AT HENARATGODA-

1. 2.

TAPPING FROM BASE TO 50 FEET.

Photo by //. F. Marvtillan.
TAPPING FROM 6 TO 16 FEET-

t>ARA RUBBER. 105

though thirty j'ears old, have never been tapped. The result in the
stems are very high, and present smooth surfaces such as one would
desire for ideal tapjjing operations. Such trees are occasionally found
on a few rubber properties in Cej'lon, the Straits, and elsewhere, but
it is not hkely that similar dev^elopment will be allowed on rubber
properties now being planted. Generally speaking, the planters
who are laying out tlieir estates desire to obtain some return as
early as possible, and their object will probably be to prevent the
production of tall heavy timber trees and to accentuate the growth
of the lower part of the stem up to 15 to 20 feet, in order to secure
the minimum girth required for commencmg tapping operations.

It is for this reason that the following results should not be
taken into too serious consideration, as they have been obtained
from the old and previously untapped trees at Henaratgoda. In the
Henaratgoda experiments the trees have been tapped at various
heights: (1) from the base to a height of 5 and 6 feet; (2) from
6 to 1(3 feet only ; (3) from 10 to 20 feet ; (4) from 20 to 30 feet ; (5)
from the base to a height of 30 feet ; and (6) from the base to 50 feet,
The following are the details of tlie experiments and the results
obtained up to date : —

V ■ 1 Weight of

.of

]Sio.ot Times ^_„„

Dry Rubbe

Trees.

tapped.

sq. in.

obtained,
lb. oz.

Base to 5 and 6 feet

. . 12,414|

..50 Oi

6 to 16 feet

796J

. . 4 loa

10 to 20 feet

. l,472i

.. 6 9i

20 to 30 feet

16 .

. 1,424£

.. 4 lU

Base to 30 feet

. 1,666

. . 4 6t

Base to 50 feet

. 2,726

.. 3 4}

The higher parts of such trees can be tapped alternately with the
lower parts, but how long this can be continued it is impossible to say
at the present time. The illustrations show one specimen tapped
from the base to a height of about 50 feet, and another being
tapped from 6 to 16 feet from the base.

The amount of labour involved in tapping such large areas on
a large number of trees is beyond comparison with that required for
the ordinary basal and more accessible tapping.

Latex from High Parts of Old Trees.

It has been previously pointed out that the cortex of the seedluigs
of Hevea brasiliensis and the cotyledons of the seed itself possess a
large number of laticiferous channels, but the latex obtamable
therefrom is usually very sticky and the dried product of low
commercial value. Rubber prepared from two-year-old trees of
Hevca brasilie)isis is sticky and easily snaps when lightly stretched ;

(1^)

106

PARA RUBBER.

that from lour-j-eai-old trees or from stems wliicJi have a ciicum"
ference of about twenty inches, though it does not possess the
properties which manufacturers most desire, reaUzes a price which
is, to the producers, satisfactory. When a tree is tapped for the
first time, thougli it may be from 4 or 29 years old, the rubber
obtained from the latex is ajjt to turn soft, stick3'', or tacky, on
keeping.

Occurrence of NoiS-coAGUAL.iBLE latex.
Ordinary tappings of medium- sized mid old Hevea trees usually
give good rubber wlien the tapping operations are carried out ou
the basal part (base to 5 or 6 feet) ; it is curious, Jiowever, 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 constitu-
tion. The latex from liigh parts of very old trees is often very
watery, and possesses a low percentage of caoutcliouc ; on treat-
ment 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. Tlie following results *
were obtained in Ceylon : —

Height of tapping area,

Base to 5 or 6

„ 6 to 16

„ 10 to 20
., 20 to 30

„ soft.

feet

Number of times
tapped .

1,165
95
94
94
171
84

Numlun- of times, ^'^}' ^^^^^- y[
when latex not .t^PPings giving
coagualable. ' non-coHgualal>lu
latex.

II
1
1
2

0-77
1-0,-.

1-U(i
212

u-o;j

5-95

The number of times when non-coagualable latex has been ob-
tained 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 witli tho latex
secured when tapping from the base to a height of 30 and 50 feet.

* Rubber Cultivation in the British Empire ; Messrs. Maclaren and
Sons, Shoe Lano, London, 1907.

iJB-f^

>}:^JtS '■ "at».€a>-wr

Photo hy M. Kehvay Bomber.
PARA RUBBER IN CEYLON.

AMHAI-AXCOnA DiSTKICT.

Two-Ykar-Old Para KrHHKU Thicks.

CHAPTER IX.
WHEN TO TAP.

Age or size as criterion — Resin in yomig trees of Castilloa Rubber —
Analyses of rubber from 2, i, 6, 8, 10 — 12, and 30-year-old Para
rubber trees — Two-year-old tree illustrated — Age of tapping trees
in the Straits — Age of tapping trees in Malacca — Age of tapping
trees in Ceylon — Age and size considered — A manufacturer's
opinion of rubber from 8-year-old trees — Minimiuu size for tapping
— How to increase the tapping area illustrated — Measurements of
forked and straight-stemmed trees at Henaratgoda — The best
season for tapping — Tapping during i)criod of rapid bark renewal
— Atmospheric conditions and the flow of latex — Results in Strait
Settlements, Ceylon, Java, F. M. S, and Nicaragua — Results of
Ridley, Haas and Arden — Latex flow dm'ing the leafless phase
— Use of ammonia and formalin — What part of the day to tap
— Yields in morning and e^•ening — Compass tapping — Frequency
of tapping and results at Heuaratgoda — Yields obtained by tapping
ever>' day, every tilterurte clay, twice per week, once per week,
once per mouth — Frequency of tapping on Vallambrosa Rubber
Estate — Frequency wlion ta])ping young trees on Lanadvon Estate.

IN discussing this part of the subject it is necessary to take into
consideration the age and size of the tree so as to determine
when it may be tapped for the first time

Several botanists have argued the question, and as it is one whicli
concerns the quality and quantity of the latex and the dimensions
and pli3\sical condition of the tapping area, it needs to be con-
sidered carefully.

Importance of Age.

Vie and Seeligmann state that in tlie Amazon District the tree
requires J 5 years to come to tapping maturity in open plantations
and 25 yeais in the forest, and one cannot lielp concluding from this
statement that either the cultivated plants in the East thrive much
better in their land of adoption than tlie wild ones in their native
habitat, or that the collectors are less eager to commence tapping
operations in the Amazon District than in Ceylon and Malaya.

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, believed that the trees in Ceylon shoukl be tea
years old before commencing tapping operations.

108

PARA RUBBER

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.

Analyses of Young Castilloa Rubber.

If one studies the many analyses of Castilloa rubber quoted by
Weber and the publications of the West Indian Botanic and Agri-
cultural Departments, lie cannot help being strtick with tlie 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
caoutchouc and 7*4 per cent, of resin. The rubber from four-year-
old Castilloa trees has been shown to contain 64-1 per cent, of resin
as against 8*2 per cent, for twelve-year-old 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 3-77 per cent., and the main trunk only 2-61 per
cent, of resinous substances. If the rubber contains a very liigh per-
centage 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.

Analyses of Paba Rubber from different aged Trees.

Moisture

Ash

Resin by acetone ex

traction
Proteins
Rubber

2 yrs. old.
0 -700/0
0-50 „

3-60 ,,

4-00 ,,

91-20 „

100-00

4 yrs. old.
0-65%
0-30 ,,

2-72,,

1-76 „

94-58 „

6 yrs. old
0-55%
0-40 ,,

2-75,,

1-51 „

94-79 „

100-00

Resins extracted by
glacial acetic acid...

Moisture

Ash

Resin

Proteins

Caoutchouc

&yrs
0
0
2
1
94

74% .

. 2-62o/o ..

2-65%

.old.

10-12 yrs. old.

30 yrs. old.

85% .

. 0-20% ..

0-50%

14„ .

0-22,, ..

0-25 „

66 ,, .

2-26,, ..

2-32,,

75 „ .

. 2-97 „ ..

3-69 „

60 „

. 94-35,, ..

93-24 „

100-00

100-00'

Nitrogen

0-28%

0-48%

0-59%

PARA RUBBER. 109

The above analyses* sliovv the chemical composition of Ceylon-
grown Para rubber prepared from trees varying in age from 2 to 30
years. It will 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 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 slightly stretched ; it was obviously unfit for sale.
The illustration here reproduced, shows the tree from which
the rubber was obtained ; it is perfectly clear that the available
tapping area on such trees is very small.

Parkin proved that the preparation of good rubber from young
stems and leaves of Hevea hrasiliensis was an impossibility, and
other observers have shown that rubber from young trees is adhesive
and lacks the required elasticity and strength ; nevertheless, it is still
the subject of much discussion as to whether age is the only criterion
for cultivators of Para rubber in the East.

Stanley Arden has shown that in parts of Malaya the rubber
from trees 3i to 4 years old is decidedly inferior. His results
have been quoted in the section dealing with " Yields of Rubber."
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 only obtained when the trees were
about or over seven years old. He calculated that by the time
the trees in jMalaya are six years old, 75 per cent, should give
an average yield of 12 ounces.

On certain Malacca rubber properties the Para rubber trees,
even though catch crops have been taken off the ground during the
first few years, attain in four years a circumference of 18 inches,
and in seven years 35 to 40 inches. These trees are planted 15 feet
apart and can be very lightly tapped after the fourth year.

Samples of Para rubber from four-year-old trees have, however,
been deprecated in certain quarters, and in one case they were classed
as being similar to common Africanf 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 quaUty of
African."

Age and Size.

With regard to our experience in Ceylon it should be pointed
out that under favourable circumstances the Para rubber tree will

* Committee of Agricultural Experiments, Peradeniya; M. Kelwfiy Beraber.
f India -Rubber Journal.

110 PARA RUBBER.

show an increase in circumference of about 4 to 5 inches per year up
to the first six or eight years, and thatthougli tlie rubber from two-
to six-year-old trees is adiiesive, and may Jiave a liigh percentage
of resinous compounds, it is by no means always the case. The
analyses of Para rubber from 2-, 4-and 6-year-old trees have been
previously given, and though the results cannot be accepted as con-
clusive, it was pointed out by Mr. Kelway Bamber* that the rubber
did not possess a very liigh 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 Para rubber tree in Ceylon is such that
a circumference of 20 inches cannot be attained much before the
fourth, fifth, or sixtli year, it is obvious that, under ordinary
methods of cultivation, all ideas of extracting rubber from trees
under these ages should not be encouraged.

One manufacturer is reportedf as saying that the rubber does
not attain its full strength until the tree is at least 8 or 9 years old,
and material from younger trees "has not the strength of hard cure
Madeira fine Para, and is uneven in strength." It is also asserted
that there is no difference noticeable in the rubber from 8-year-old
trees from different plantations, but it is not yet safe to use it for the
finest work, such as thread and the best bladders.

Minimum Size for Tapping.
If the tree has a circumference of much less than 20 inches,
tapping cannot be recommended, because the available tapping
area is too small ; nevertheless, on several estates the trees having a
circumference of only 15 to 18 inches are tapped. The production
of new tissue would be a strain on the young plant, and the thin
bark tissues would probably be quickly cut away long before the
desired quantity of rubber had been obtained.

If the circumference is anything above 20 to 24 inches, a yard
from the ground, and the tree is four to six or more years old,
it can, in Ceylon, be lightly tapped. I have seen good rubber from
such trees. A tree 24 inches in circumfeience cannot have move
than two spiral curves for tapping; it could be tapped on the
lierring-hone system on one or both sides of the tree.

On one estate in Ceylon 41 trees of considerable height, but
liavim' a circumference of from 18 to 25 inches a yard from the
ground gave with very light tapping during March and A])ril 19Mb.
of dry rubber, which was favourably reported upon in Europe.

From the foregoing remarks it is clear that the questions of
available tapping area and age cannot be neglected ; they are as

♦ Committee of Agricultural Experiments, Peradetuya. M. Kelway Bamber
t India-Rubbor World, December, 1905.

PARA RUBBER. Ill

important as the ages of the trees. A ininiuuim circuinfereiice of 20
inches, a yard from the ground, and a minimum age of 4 to 6 years
■ can be accepted for most rubber properties, the better developed
trees being tapped first.

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 previously 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, and a
very striking illustration is to be seen in the first clump of old Para
jubber trees in the Henaratgoda Garden, Ceylon. The dimensions
of forked and straiglit-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 folloAving are
the dimensions of some of the low-branched and straiglit-
stemmed trees : —

Henaratgoda Trees.
Circumference of trimik, in inches, a yard fi'om the grountl.

Trees with Tree forked at Tree forked at Tree forked at

long straiglit 11 feet from 7 feet from 9 feet from

Stems. Base. Base. Base.

Inches. Inches. Inches. Inches.

61, 65, 83, 85, 76 109 . . 104 . . 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 yomig plants it is an easy matter to nip off the
terminal bud of the main stem, when the desired height has
been obtamed; this is usually followed by the development of

ii2 tARA RUBBEia.

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 increased quantity
of foliage , whereby a larger food suj^ply 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 Para rubber trees in Ceylon drop their leaves in February
or March, produce new leaves and flowers after a leafless phase of a
few days or a couple of weeks , and yield ripe fruit in August and
September. There is an active vegetative period from September to
December ; a short, marked, resting period in February ; and a floral
and fohar condition from February to September. The climate
during these months has been dealt witli in Chapter III.

The trees of Hevea hrasiliensis exhibit a definite foliar flower and
fruit periodicity, and though they will stand tapping throughout the
year it is questionable whether periodicity in tappmg should not
be done m 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 l)e formed wherein new laticifers can be
produced. The periodicity of the trees varies according to climatic
and other factors, but the period including the fall of leaf, the leaf-
less phase, and that of fohar renewal appears to be the most critical
one. In most parts of the Straits Settlements, according to Ridley,
f lom December to March is probably the restmg or relatively mactive
period and the bark renewal during these months cannot take place
as rapidly as during the rest of the year. 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 j'oar, but the above
consideration should, whenever practicable, be allowed for.

Several writers have associated the yield of latex with atmos-
pheric conditions, the general contention being tliat 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 liis experiments in Java, concludes that
if the humidity of the soil is great, and if the rains are equally distri-
buted, the difference in 3'ield during tlie year is not great, and he

PARA RUBBI:R. 113

fiiit \\vr 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.

In parts of the F. M.S., where the cHniatic periodicity is not so
strongly marked as in Ceylon and Soutli India, theie is said to be
but little variation in the yield of rubber during different months.

"Mr. Larkin. whose estate at Castlewood* I have recently
visited, tells me that during the late dry month of March all his
trees in one part of the estate shed their leaves simultaneous!}', and
remained bare for a time. He continued to tap during this period .
and found no diminution in the amount of latex produced."

According to the above theory, the yield of latex .should be
most abundant 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 wlien the
leaves were beginning to appear or wlien in full foliage. In Nicaragua
the latex from other rubber trees contains the highest percentage of
caoutchouc during the dry season. The j)ossession of abundance
of latex during the dry season lends support to the tlieory of its
functioii as a water store during drought.

In many parts of the tropics, however, the leafless period occurs
when the dryness and temperature of the air are at the maxi-
mum,vand the collecting of latex would, during such a time, be
limited to the very earty part of the day J 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 comparativelv
low. A period of drought lasting only seven or twelve days
appreciably afiects the flow of latex, but though, under such con-
ditions, the quantity is reduced, the quahty is usuall}'^ improved.
The latex rapidly dries on the tree in hot dry weather ; this can .
liowever, be overcome by the use of ammonia, formalin, &c., placed
in the drip-tins at the top of each incision. In the Amazon valley
the native collectors never tap the trees when in flower, as tiiey
believe the amount of rubber then obtainable is much less than
at other times — an idea supported by Ridley's experiments at the
hotanic Gardens, Singapore.

It is vrry unlikely that the collection of latex will be limited to
the dry peiiod, when the trees pass through their foliar phase,
and in practice tapping du''ing almost every month is much more
Ukely to be adopted.

* H. ?f. Ridley, Agri. Bull. Straits and F.M.S., May, 1904.

(15)

114 PARA RITBBER.

Results at Henaeatgoda.

Regarding this question the results given below may be of value.
The trees marked '"H" were first tapped when the leaffall
commenced, and the operations were continued through the period
of leaffall 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.
The experiment was made at Henaratgoda.

Yield of Dry
Number of Times Rubber

tapiDed. per 5 trees.

lb. oz.
Trees tapped every day from

October 1, 1905, (I) . . 157 „. 38 12^

Trees tapped every day : first

tapped on February 1, 1906 (H).. 08 .. 13 14^-

The tapping operations (I) were continued at Henaratgoda
right through the dry months of January to April ; towards tlie
end of the latter month the flow of latex was noi c >pi'yus, and in
some cases the coagulation, instead ot being complete in 24 hours,
required a period of nearly two days.

On estates possessing rubber only it is diTicult to see how the
labour can b kept employed if tapping is suspended during the dry
months, and the point to determine is the maximum frequency that
the trees can be tapped with the minimum damage to the tree
during these months. The above phenomena were observed in
trees (I) which had been regularly tapped from September, 1905,
to April, 1906, during wliich period the trees shed all then- leaves
and produced new foliage and flowers.

What fart 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 9 a.m.,
and re-commenced at 3 to 4 p.m. All-night tapping is of course
only possible when the artificial lighting of estates is more perfect
I ban at present.

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*

♦ Annual Report of the Director, Botanic Gardens, Singapore.

Photo by Ivor Etlic>ii>gtoit.
HEVEA BRASILIENSIS TAPPED EVERY DAY-

PAHIX(; & PHICKIXG METHOD.
0 LB. DRY RUHBKR FROM 264 TAPPINGS.

PARA RUBBER. 115

the girth of the tree decreases during tlie day and increases towards
evening, an observation which nui}'^ throw some hght on the theories
regarding tension of the haticiferous tissue and transpiration.

Ridley also states (Annual Report of tlie Botanic Gardens,
Singapore and Penang, for 1904) that the most favourable times
for tapping are morning and evening, and from the same number of
trees wliich ])roduced a total amount of 578 lb., tlie morning trees
realized 314 lb., while the evening trees gave only 2G3 lb., showing
a difference in favour of the morning tapping of 51 lb. Ridley
and Derry concluded that evening tappings to be successful should
be deferred to as late an hour as possible.

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 ; ^uch a method,
appUcable to the east and west sides of the tree, prevents direct
exposm-e of the tapping area to the sun's rays during working
operations, and allows the flow of latex to continue for a slightly
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 (lie wound response to
'become obvious is of interest and importance.

It is perhaijs 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 Jiave never been
tapped before. Nevertheless, it is of interest to learn that in those
districts the Para rubber tree 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
out the year, has given good yields.

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

116 t>ARA RUHBEH

were comiiiciioed in Septbmber, 1905, and ended in February, 1906,
the full spiral system being adopted in all the cases quoted below,
from the base to a height of five to six feet.

These results suggest that the average aiujuiit o[ rubber,
obtainable per tapping operation, is likely to increase when an inter-
val of OTIC or nioie days is allowed between successive operations.
They also indicate that the average yield, per tapping, is better when
the trees are incised every alternate day than when tapped once pet-
day oi- once per week ; at Singapoie the yields obtained l)y tapping
ever}' da_y were better than those secured by tapping ever^r
alternate day. From a practical standpoint, however, the
total quantity of rubber obtainable when the trees are judiciously
t apped at regular intervals is of more itnportance than the deductions
just made ; the latter must not be construed as contradicting the
accepted theory of wound response previously discussed.

Yield of Dry Yield of flub
Frequency of Number of Number of Rubber per ber per tap-

Tapping. Times tapped. Trees.

Ever J' day (D) . . lOS „. .5

Every alternate day(E) 83 . . a

Twice per week (A) .. r>7 .. 25

Once per week (F) .. 28 ..5

Once per month (G) 7 . . 5

The following table* sliows the results obtained in (Joylon by
tapping trees at different periods during eleven months : —

ive trees

pmg, per
five trees,

Jb. oz.

OY.

42 li

.. 4-0

49 11

.. 9-5

14 0

. . 4-0

12 0-

.. 7-7

0 1,5 j

.. 2-1

Krequoucy uf

umber uf times

umljor

Yield of

dry lulj-

tapi>iiig.

taliped.

trecp.

ber pe
11).

V tree.

Kvory day

270

;")

1 1

Kvery alternate day

i;3(i

.">

\-2

Twice per week

•_';')

•1

(Jnco per week

•\

i:i

Onco per month

i«

Feeque>cy of Tapping .\t Sing .\ poke.
Ridley's experiments (Ag. Bull., December, 1906) have been
carefully carried out on the trees in the Botanic (Jardcn at Singa-
pore, and the following results were obtained up to December 1906 : —

On 50 trees, averaging in girth 3 ft. 7 in. tiie tappings ijicluded
one evening period, and it was noticed that the ratio of caoutchouc

* Scionco of Para lluhhtn- Cultivati'iii : A. M. ifc ,1. Ferguson, Colombo,
)9UT.

Photo by Ivor Etherhigton,
HEVEA BRASILIENSIS TAPPED EVERY ALTERNATE DAY.

PARl.VO it PHICKIXG METHOD.
U 1.11 imv HI:HHKR from 181 TAf'HlX<«S

MRA tlUBBER.

117

to latex for the second pci'iod or evening (a])pings was better than
the first or morning tappings, although the interval of rest was
only 2^ months or slightly less.

In the second experiments carried out on 1-0 trees averaging
about 3 ft. in girth, the interval of rest between the two
periods of tappings was under 1| months, the second comparuig
unfavourably with the first period, and tbe evening poorer
than tlio morning.

In the tliird exj)eriment 140 trees, with an average girth of

2 ft. 5| in. exactly an interval of two months' rest was allowed;
the result emphasized the necessity of a longer j)t"'htd and the
advantage of morning over evening tapjiing.

In the fourth experiment cairied out on 207 trees averaging

3 ft. 2| in. in girth the variations of different groups were strikingly
illustrated.

The fifth was an experiment confirming the necessity of an
ijiterval of rest of six months, and the advantage of morning over
evening tappings. The trees were 200 in number and averaged
3 ft. 1|- in. in gnth.

The sixth experiment shows that daily tappings gave^ at
Singapore, a better result than tappuig on alternate days.

Tapping Seasons.

The results for a period of one year with the garden trees
wore as follows : —

— *
= a

;^s.

li.

lii.

»>

IV.
VI.

Groups

of
Trees.

»»

120

»
140

200

150

Average

girth

per

Tree.

Ft.
3

In.

Period of Tappiiij

1905.

Aug-Sept.
Nov-Dec.

Sept-Oct.

Dec.
Sept-Oct.

Dec.
Oct-Nov.

Oct-Nov.

Nov-Dec.
Jan.

1906.

Ratio of
Fluid oz.
to 1 oz.
Dry rubber
Avoirdu-
pois.

Juae-Julj'.

i Jau.
Mar-April
Wav.

c/c
^ 5 M-I6th
)-5 3-16th „
J4 1i.l6lh„

-1-1

3 11-lGth„
16th „
) 5 1-lGth „
j i 5.i-16th „

5 3-16th „

No.of tiiucH
year. j

[I3i;

. ; 1 7-

June-July.lj 3 9-16th

1st Period

2nd „

3rd „

1st „

2nd „

1st „

2nd „

1st „

2nd .,

1st „

2nd „

1st „

2nd „

Mornings
Evenings
Mornings
Mornings
50 trees
Evenings
Mornings
Evenings
Mornings
Mornings
Evenings
Mornings
Mornings

Moruinss

Hidley concludes that '" mornings are better than evenijigs
tappings, that trees can be tapped twice within the period of a

118 PARA RUBBFJR.

year, but the interval of rest should not bo Iciw than live months,
that the dormant months December, January and February yield
a smaller percentage of caoutchouc, and that the best season for
tajjpijig is from April to November."

On the property of the Vallambrosa Rubber C!o., Ltd., the
excision system of tapping is employed and the half-herring-bone
plan adopted. TJie trees are tapped at intervals of four months
for 14 to IG aUeiiiate days at a stretch and good yields obtained.

On Lanadron Estate, F.M.S., the young trees when tapped
vn the basal V. system can be operatod upon regularly about
ever}' other day throughout the year.

— -s=<t^^^^Bv<©0- -

BASAL TAPPING

TjlK Y SVSTKX.

Plwto fiy Clias. Northxi'oy.

Basai. Spirat, Links.

CHxYPTER X.
YIELDS OF PARA RUBBER.

Natural variations Yields in Brazil and Ceylon -Heiiaratf^oda trees and
Amazon yields — Yields on estates in C^eylon : Matale, Uva, Kalutara,
and Andialangoda Districts — Illustration showino- the rubber trees on
Passara (iroup Estate — :( to ')\ lb. averages over large acreages- Yields
obtained in the Kaluta#a District for 1905 by the Kalutara Rubber
Co., Kayigam Tea Co., Neboda Tea Co., Vogan Tea Co., Southern
Ceylon Tea and Rubber Co., Putupaula Tea Estate Co., Yatiyantota
Ceylon Tea Co., Eastern Produce and Estates Co., Sunnygama Ceylon
Estates Co., Y'ataderiya Tea Co., Kepitigalla and Passara Group
Estates, Ceylon Tea and Cocoiuit Estate Co., Ambalangofla Estate,
Balgownie Rubber Co., Pataling Riibber Co., and Gikiyanakanda
— Yields on Imboolpitiya estate, Nawalapitiya — Illustration show-
ing rubber trees at Peradenij'a tapped on the full spiral system —
Exceptional yields at Culloden, Elpitiya, and Peradeniya — Comparison
of yields at Peradeniya and Henaratgoda — Experiments at Henarat-
goda — Comparative yields from different systems of tapping — Spiral
and herring-bone tapping compared — Yields obtained at Henaratgoda
in 11 months — Results of high tapping at Henaratgoda from base to 50
feet — High yield from basal tapping only — 16 tappings yield :^i lb.
rubber — Average yielding capacity per square foot of the bark tissues
— Comparison of yields obtained at Henaratgoda- Illustration show-
ing the Elpitij-a tree after 14 lb. rubber extracted — Y'ields at
Peradeniya by the V and spiral methods— Rubber from shavings —
Rubber Yields in Malaya — Yield from young trees on Lanadron
Estate — I'ield from old trees at Singapore — Yield during 1906 in
Federated Malay States, Straits Settlements and J chore — Y'ield during
1905 in Selangor, Perak, Negri Sembilan and Pahang — Y'ield from the
Sandycroft Rubber Co., 19U5 — Variation in yields in Java — Y'ields in
South India at high elevations — Hawthorn Estate and Mergui Rubber
Plantations — Para yields in the Gold Coast — Yields of Para and
African Rubber compared — Yield per tree during 1906 and 1907 on
the properties of the Consolidated Malay ; Anglo American Direct Tea
Trading ; Anglo Malay ; Black-water ; The Kalutara Co.; Kepitigalla ;
Pelmadulla; Yatiyantota; Shelford; Sandycroft ; Ledbury ; Yataderiya ;
Perak : Bukit Rajah ; Vallambrosa ; Highlands and Lowlands ; Cicely ;
Pataling ; Asiatics ; Consolidated Malay ; Eastern Produce ; Golden
Hope ; Shelford ; Union Estates ; Bertram ; Balgownie ; Kuala Lumpur ;
Rubber Plantations ; Kalumpong Estate — Yield per acre on Kuala
Selangor Co. ; Malay States Cofl'ee Co.; Rubber Growers Co.; Selangor
Rubber Co.; Seremban Estate Rubber Co. — Total yields from estates
in the East from 1905toi908 — Official returns for Federated Malay
States 19U7 — Yield and distance apart of trees — Y'ields on various fields
of the Vallambrosa Rubber Co. — Yields on fields of the Highlands
and Lowlands Estate — Y'^ields from trees of known girth at Singapore
— Cost of Rubber production on properties of Asiatic Rubber and
Produce Co. ; Highlands and Lowlands Co. ; Pataling Rubber Estates ;
Vallambrosa; Vogan; Yatiyantota; Seremban Estate; Balgownie;
Kuala Lumpur — Annual increase in output from estates ; Gikiyanakanda
from 190H to 1908--Difficulty in forming average estimates of yield

Natural Variations.

TI/'HEN dealing with the question of yields of diy rubber for a

f f known acreage or number of trees, it is necessary to indicate

the method of tapping adopted, the age of the trees, and the quality

120 PARA RUBBER

of the resultant rubber. Tlie age and size of trees greatly influence
tlie quantity and quality of the rubber, and it is to be regretted that
the yields over large acreages for several years in succession are not
at liand. Nevertlieless, we do possess information of the yield of
particular trees duiing certain years and of large acreages of known
•a.%e for a limited period, and from these a fairly reliable statement
of probable yields can be arrived at. It should be clearly under-
stood that the jaeld 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.

It should also be remembered that individual trees, either from
internal or external causes, show considerable variation in the quan-
tity and quality of latex they give, though of the same age and
tapped in a similar manner. At Henaratgoda, where the trees
ranf^e in age from 15 to 30 years, and where tapping has been done
on various sections of tlie trees from the base to 6, 16, 20, 30,
and 50 feet, the opportunities to observe the variation in yield of
Utex 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, have given a yield varying from six
twenty-fifths of an ounce 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 three-fifths of an ounce to
five and one-fiftli ounces, one-quarter to one and one-twcntietli
ounces, nine-fortieths to thirty-three fortieths of an ounce, &c., and
in one case, where the tree has been regularly tapped from the bas •
to a height of 50 feet, the yield of dry rubber has sometimes been as
high as eight and three-quarter ounces per tree per tappinor, and
on other occasions as low as a quarter of an ounce. Such
variations can, in most cases, be mainly attributed to internal
conditions rather than external climatic forces. Results of tapping
operations are available from different countries, and it will be
best to commence with those obtained in Brazil.

Yields in Brazil.
In Brazil, from a group of 120 to 180 trees, eacli man is expected
to collect about 8 to 10 htres of latex, and though this is regarded as
a fair average, as much as 40 litres (10 gallons) have been collected
from such a group in one day. Bonnecliaux* asserts that the average
vield of rubber per tree, per day, is from 2G to 33 grammes, and
that a grou]) of 150 trees will yield during tlie tapj)ing season in each
year 400 to 500 kilos of caoutchouc.

Seeligmannf states that in the Amazon valley as iiuuli as 30 c.c.
of milk are obtainable from single oblique incisions, the lat«x

♦ See JvxmHlle I.e.

t Sceligraann, Caoutchouc et la Qiitta Percha p. 4:

Photn by ' olomho ApotlvXcirie-s Co.
PARA RUBBER IN CEYLON-

RUBBKR AXD CaCAO IN BEARING, MaTALE.

Danoan Estate, Rubber Plantations, Lto.

PARA RUBBF.R. ' 121

flowing from one to tliree lioui-s. Parkin was of the opinion tiiat
the Amazon yields were far in excess of tliose obtainable in Ceylon,
and gave a modest average of 2 to 3 c.c., which might be worked
up to 10 to 12 c.c. of lal«x as a yield to be expected from single
oblique cuts in Ceylon.

Rubber Yields in Ceylon.

The yield of rubber varies from 7 lb. per 400 trees in one
tapping to a maximum of 25 lb. per tree in twelve months' tapping.

The first series of reliable yields* were those obtained at Hena-
ratgoda from 1888 to 1896. One tree at Henaratgoda was lightly
tapped every second year, and gave for nine years an average annual
yield of 1 h lb. of dry rubber : —

27|oz. in 1888

42 oz. in 1890

;") oz. in 1892

51 oz. in 1894
48] oz. in 1890

Tiiis tree was twelve years old wiien first tappea, and the
annual yield of 1 J lb. was from the 12th to the 20th year of the tree's
life. The metliod of tapping consisted of scrapmg off the rough
outer bark and making numerous V-shaped incisiorts to a height of
about five feet. The tree had a circumference of 50 J- inches and was
growing with other trees of nearly equal size, distanced 30 feet apart.

Other experiments have been made at Henaratgoda which in-
dicated similar results by consecutive weekly tappings of the trees.

Yields on Estates in Ceylon.

To form an estimate of the yield to be obtained from large
acreages of Para rubber trees of known age is no easy task, and the
best way to deal witli this part of the subject is to give only the
results which have been obtained on rul)])er estates in the island

Matale District.
In the Matale District there are estates where an average yield
of I 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 311b. 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
rubljcr ])er 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.

* Dr. Trimcn, Notes on Rubber Experiments.

(16)

122 PARA RUBBER.

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 will probably be increased by a change in the
method of tapping and tapping instruments.

On a third Matale estate the Para rubber is 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 is expected
the trees being 8 to 15 years old. On this estate several encourag-
ing 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 Group
estate, Passara, Para rubber 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, and I have to thank
Mr. W. Stewart Taylor for the information he has given me. An
illustration showing the rubber trees at 2,600 feet above sea- level
is here reproduced.

A considerable amount of Para rubber is likely to be planted
in the Badulla, Passara, IMonaragala, and Bibile Districts, and in
many cases the altitude is considerably over 2,000 feet.

South Ceylon : Kalutara, Amhalangoda, Rayigam, die.

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 twenty 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. There are on this estate four old trees which have given
10 to 25 lb. of dry rubber per tree in twelve months ; the trees are
perfectly healthy, and give a good crop of sound seed every year.
Further tapping has been done on these trees with excellent results.

A section of another rubber property in the South of Ceylon
gave, from 11-year-old trees, the average circumference of which was
30 inches only, no less than 51 lb. of dry rubber from each of 255
tr«es. The eight largest trees on tliis property yielded no less

P/ioto lent by t/w Kegalle PLintcrs' Association,
TAPPING MATURE TREES. YATADERIYA ESTATE, KEGALLE.

PARA RUBBER. 123

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.
Tliese results have been obtained by the half or full spiral system
of tapping.

The quantity of rubber harvested during 1905 in the Kalutara
District was 101,978 lb. from 88,667 trees, which shows an average
of about 1*15 lb. per tree. A large number of these trees, about 43
per cent., were tapped for the first time, but as nearly all the older
trees in the district are planted in selected spots and at great
distances, the Kalutara Association do not expect to see any
increase in the yield per tree for a considerable number of years.
As yet there are insufficient trees in bearing in rubber alone to
enable the Kalutara planters to estimate with any degree of
certainty what the yield per acre is Ukely to be.

During the year 1905 the Kalutara Rubber Company, Limited,
tapped 1,135 trees, and obtained a yield of IJ lb. of rubber per tree.
The Ceylon Tea & Coconut Estates Co., Ltd., tapped in 1905, 1,751
trees, and obtained 958 lb. of rubber.

The rubber trees on the property of the Rayigam Tea Co., Ltd.,
were tapped in 1905, 2,2201b. of rubber being obtained fro about
1,800 trees.

The Neboda Tea Co. of Ceylon, Ltd., in their aim ual report for
1905, state that 370 trees reached the tapping stage during the year,
and gave 820 lb. of dry rubber or an average yield of 2| lb. per tree
per annum.

The Vogan Tea Co. of Ceylon obtained in 1905 a crop of 3,056
lb. of rubber from 2,800 trees ; the cost of harvesting, including all
expenditure on tapping knives, cups, &c., being Re. 1*05 per lb. of
rubber.

The Yataderiya Tea Co. secured, hi 1905, 2,855 lb. of rubber
from 5,324 trees, the greater number of the trees being only Hghtly
tapped towards the close of the season.

The Soutliern Ceylon Tea & Rubber Co. , in their report for
1905, state that in about 8 months' tapping, from 577 trees, 614
lb. of rubber have been obtained, most of the trees being in their
seventh year.

The Putupaula Tea Estate Co. , Ltd. , in their annual report for
1905, state that 4,982 lb. of rubber were harvested, the crop being
equal to If lb. of rubber per tree.

The Yatiyantota Ceylon Tea Co., Ltd., report that during 1905
the crop of rubber amounted to 8,212 lb. from about 4,636 trees, of
an average of 1 f^ lb. per tree.

124 TARA RUBBER.

The Eastern Produce & Estates Co., Ltd., report for 1905 that
>«,515 lb. of rubber were obtained, and tJiat 12,00(J trees would
bo available for tapping in 190(5.

During 1905 one hundred I'ara rubber trees on the property of the
Suunygama Ceylon Estates Co. , Ltd. , gave 3[ lb. of dry rubber each.

Yields oin Gikiyanakanda fok 1905.
The results obtained on the above estate for 1905 are of
importance as showing rehable details of yield and dimensions of
trees. During the year, 5,598 trees were tapped ; of these, 2,207
had been previously tapped. Between January and March 1,340
new trees were operated on for the first time, and again between July
and October other 2,045 trees were taj^ped 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 on-
wards, others only from October, was 7,592 lb. or 1-34 lb. per tree.
It is interesting to know that the total cost per lb. for collecting,
including knives, tins, &c., Avas 53-40 cents and for curing ()-25 cents
per pound of rubber. I have to tliank Mr. (I. H. Gollcdge for his
kindness in favouring me with tlie results of his work during 1905.

Yields on Imbuolpitiya Estate, Nawalai'itiia, Clylox.

All interesting scries of yields, for which I am hidebted to Mr.
Albert Rosling, has been obtained on the above estate, situated
in the Ambagamuwa District, at an elevation of 2,000 feet, where
the rainfall average for 20 years is 1441 inches per year.

The tapping operations were commenced on 18th December,
1905, and terminated on 18th March, 1906, so[that the collection of
the latex was carried out during three very dry months and througii
the period when the trees changed their fohagc. The following are
the yields obtained, inclusive of scrap : —

Age of Trees. Number of Tiraos Weight of Dry Rubber

^ ' obtained in 3 months.

One tree 28 years old 17 3 lb. 7 oz.

Two trees ,,,,,, 21 117

Thirty-six young trees
Ten

The two trees, 28 years old, gave during September and
October, 190o. 12,(XM) seeds ; the other tree of the same age seldom
yields more than 400 to 500 aeeds annually.

Photo I art by A. IV. IV Gnn .
PARA RUBBER IN CEYLON-
KrurN-KOAi.A DisTHtcr,
l.wi'isu .AlATLiii: Ti!Ki;s IN V.m. Akami'oi,a Estait, Ki-Ri-xixAr-A. CKYr.oX.

PARA RUBBER.

1^5

Comparison of Yij-xds fkom Ci'Iylon l^RorERTiES int 1905.

Having indicated ilic yields obtained in v arious parts of tlie world
and tiioso from estates and exceptional trees in Ceylon, (he following
synopsis is given to assist those who desire to form an estimate of
probable future 3'ields: —

Name of Rubber
Property.

Yield of
Rubber ob-
tained in
1905.

Number ' Average
of Trees Yield per
tapped, tree i)er
year.

1 Particulars
of trees
tapped.

Neboda Tea Co. of
Ceylon, Ltd., Ceylon.

lb.

820

370

lb.

j Young, and
attained tap-

j ping stage in
1905.

Pasrfara Group estate
ill Uva, Ceylon : ele-
vation 2,600 ft.

740

370

Trees 6 to 13
years old

Kahitara Estate, Cey-
lon.

Kalutara Rubber Co.,
Ltd., Ceylon.

' 15,017
1,419

8,731
1,135

1-72

Minimum cir-
cumference
of trees was
20 inches.

Kalutara District hi
Ceylon.

101,978

88,667

1-15

43 per cent,
were tapped
for the first

Vogan Tea Co. of Cey-
lon.

3,056

2,800

1-09

time.

Rayigam Tea Co. ' of
Coylon.

2,220

1,800

1-2

Putupaulft Toa Estate
Co.

4,982

Yatiyantota Coylon
Tea Co.

8,212

4,636

1-7

Sunnygama Ceylon Es-
taes Co,

325

100

31-

Yataderiya Tea Co.,
Ceylon,

2,855

5,; 24

0-5

Varied in cir-
cumference
from 18 to
61 inches.

Kepitigalla, Matalc,
Ceylon.

30,000

10,000

Trees from 8
to 15 years
old.

[Continued

jrer.]

126

PARA RUBBER.

Name of Rubber
Property.

Yield of
Rubber ob-
tained in
1905.

Number
of Trees
tapiaed.

Average

Yield per

tree per

year.

Particulars
of Trees
tapped.

Hcnaratgoda Gardens,
Ceylon.

lb.

in 4|-
montlis

lb.
1-7

in 4.^
months

The circum-
ference of
the tapped
trees ranges
froni 33 to
69 in

Gikiyanakanda, No-
boda, Ceylon.

7,529

5,598

1-34

Some tapped
for first time
others pre-
viously tap-
ped.

Coconut Estates
Co., Ltd.

95 3

1,751

0-5

Mainly young
trees.

Rubber Estate, Matale,
Ceylon.

1,088

311

Girtli of trees
varies from
30 to 70 in.

Rubber Estate, Matale,
Ceylon.

1,596

499

11-y oar-old
trees in seven
months' tap-
pings.

Rubber estate, Matale,
Ceylon.

3,750

5,000

Average girth
of trees is 35
inches.

Rubber estate, Amba-
langoda, Ceylon.

1,400

255

Average girth
is 30 inches.

]lul>ber estate, Ainba-
langoda, Ceylon, lOOi

•208

501

0-41

Tapped on V
system.

Do. ] 90r.

nos

617

1 47

Some trees
tapped spi-
rally.

Balgownio

1,010

3,200

0-32

Pataling

25,700

25,000

0.9

The trees on the various rubber properties enumerated above
differ widely in age, size, &c., and are growing in dissimilar
climates. The results are, however, of value in so far tliat they show
the yield.s obtained in an early stage of the industry, wlien our
knowledge was necessarily meagre and our methods open to
considerable imi)rovement.

Photo by C. H. Kerr.

PARA RUBBER IN CEYLON.

Kali TAHA Disthk r.

The Famous Titiax s<»mk ok whk h havi; (;ivi;n Jo i,h. ItiBUKU in »kNK Vkau.

CrtU)T>ES EsTATi:. Kaiitaha. ('i;vi.un.

PARA RUBBER.
Exceptional Yield.s.

127

These results have, however, been completely surpassed by those
obtained on exceptional trees during the last few years. Trees of
unknown ago in Ceylon (probably 20 to 25 years) have given 10,
IS, 23, and 25 lb. of rubber in twelve months' time ; other trees, only
eleven years old, have in eight months' tapping given 14 lb. of
dry rubber each, and others from 2 to 4 lb. in two to three months.
Light tapping of young trees has given 1'72 lb. of rubber per tree
on a well-known Kalutara property. These results are so significant
that space for tabulating them is here given, although it must be
clearly understood that thej' are exceptional : —

Age of Trees.

Tapping

Tappinc;

District.

period.

Yield.

method.

CuUoden

,.. 20 to 25 years

12 months

(a) 10 lb.
(b)IS ,.
(e)2:} ,.
(a)25 „

V Various

Elpitiya

. 11

12 „

](i ,,

Spiral cnrve.s
with knives
land 2

Peradenij'a .

. 29

12 weoks

ahont 3 ,,

V cuts

H months

6?„

Spiral curves
with knives
land 2

Kepitigalla .

. 8 to 15 ,,

12 monthL

— >>

V cuts

12 „

3„

V cuts

The ten old trees on Culloden were again tapped on the herring-
bone system from 1st November to the 8th December, 1905, and
gave an average of over 12 lb. of dry rubber per tree. A photo-
graph is, by permission of the Agents and Messrs. Capper & Sons,
Colombo, given elsewhere showing the trees from which tliese large
yields have been obtained. I saw these trees in April, 1908, and
was informed that they had given an average yield of 18 lb. per
annum for four years.

The Elpitij'a tree had a circumference of 46 inclies ; the tapping
was commenced in October, 1904 ; the tree was rested in November,
tapped again in December, rested in January, 1905, and continuous-
ly tapped from Februar}'^ to June, 1905. Tapping was re-com-
menced in September, 1905. This tree appeared quite healthy in
April, 1908.

Yield from Peradeniya Trees.

The following are the details of the trees at Peradeniva, whicli
were tapped either on the spiral or V system. The letter P indicates
the days on which the spur knife was used.

It will be noticed that the quantity of latex obtained by the use
of Bowman's and Northway's spur knife was usually much greater
than that obtained by the paring knife ; this was to some extent duo

128

PARA RUBBER.

to the fact that the innermost laticiferous tubes near the canihium
were penetrated by the points of the spur.

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 spur
knife was followed by a poor flow after paring.

The illustrations on tho accompanying plates show the Pera-
deniya trees referred to in the following records of yields : —

Four Peradeniya Trees — 29 Years Old :
Yield of Rubber from V Cuts.

Weight.

Weight

Date.

lb. oz.

Date.

lb. oz.

29-6-05

Brought forward

9 12|

1-7-05

19-8-05

5-7-05

111

P 21-8-05

7-7-05

22-8-05

10-7-05

P 23-8-05

I*.

12-7-05

24-8-05

14-7-05

25-8-05

17-7-05

26-8-05

1='-

19-7-05

28-8-05

21-7-05

29-8-05

24-7-05

30-8-05

26-7-05

31-8-05

28-7-05

1-9-05

31-7-05

1^-

2-9-05

2-8-05

4-9-05

oii

3-8-05

5-9-05

4-8-05

G-9-05

5-8-05

7-9-05

7-8-05

4 a

8-9-05

<'^-

9-8-05

'>7

-'H

9-9-05

10-8-05

i:;

] 1-9 05

().',

11-8-05

i«

12-9-05

12-8-05

13-9-05

«»^-

r 15-8-05

15-9-05

<>i^

17-8-05

18-9-05

y-i

P 18-8-05

Carriod forward . .

9 12^-

11 5^

The figure on tlio accompanying Plato sliows the condition of
one of the trees at tho end of tlie tapping operations ; tho lines of
adjacent V's were beginning to interfere with one anotlier, and tlie
trees were therefore rested. Tlie average yield in the first five
weeks was two pounds of rubber per tree, but subsequently the
yield fell off considerably.

PARA RUBBER.

Rubber Yield from Long Spiral Lines.

Four P^rap niya Tu.:es— 29 Y ars Old.

129

D\to
lG-6-05
:7-G-05
10-6-05
20-G-05
2I-G-05
22-(>-0j

23-G-Oo

24-6-05

2()-G-05

27-G-05

28-6-05

30-6-05
1-7-05
3-7-05
4-7-05
6-7-05
8-7-05

1 1-7-05

13-7-05

14-7-05

15-7-05

18-7-05

20-7-05

22-7-05
25-7-05
27-7-05
29-7-05

1-8-05

3-8-05

4-8-05

5-8-05

8-8-05

9-8-05
10-8-05
11-8-05

Carried forward

Wt'iph-
lb. z

134

5h
5

6k
H

lOi

m
n

Ci
5

H
H

7 Oi

Bro'igh

J2-
P 14-

16-8
P 17

18-8

P 19-8

21-8

P22

P 24-8

25-
P 20-8
28-8
P 29-8
30-8
P31-S
P 1-

2-9

P 4-9

5-9

P 6-9

7-9

8-9

9-9

11-9

12-9

13-9

14-9

15-9

18-9

t forwar
;-05
i-05
1-05
;-05
-05
!-05

lb.

1-1 5
1-05
1-05
05
1-05
05
1-05
-05
05
1-05
1-05
-05
1-05
-05
1-05
-05
1-05
1-05
1-05
1-05
1-05
1-05
-05
1-05

'g!'t.
oz

'•"I

H
H
H
H
H

H
H
H
H

7|
2J
3

i
1

n
1

17 8|

From 28-10-0) ti 16-2-0 :

= 9 lb. 10^ oi.

Total .. 27]b.ooz.

CO.MPARI.SON OF YlBLDS AT PeSADENIYA AND HeN'ARATUDDA.

flf P?'!,'^'"'^^ "''"^^^ ^^^^® ^e^" obtained from tho full spiral svstem
at Peradeniya are not as satisfactory as t'loso at Henara 'odl i^i^
are only br<e: y indicated here. At p/radcniya four t -e" tSn nea v
tt 1?/%"^'^' ^«^^tWed from June. lOJr,, to February 19 i^
lerTr'^^^' }f''^'^^^- About tlirce-quartcrs of the b^rT'tis.ae;
were removed from the base to a height of five to six feet bv altfr
oatelypnclang and paring tho lower sui-faoe. . M^^JZ ^ok!:^'^

(17)

130 PARA RUBBER.

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 4| months the width of bark
tissues removed along each hne was only li to 2 inches. The results
show that by tapping on 37 occasions a total of 50| lb. o dry
rubber can be obtained from 25 such trees.

The following shows some of the yields obtained by tapping
on the long spiral system at Henaratgoda ; each tree was tapped
from the base to a heiglit of 5 or 6 feet during a period of about
4^ months : —

Long Spiral Tapping Experiments.

Number of

Yield of

times tapped-

Trees.

Kubber,
Ib.j

112

30|i

26,V

18 «..

• 5

8 r\

100

2V'

EXPEEIMENTS AT HeNAEATGODA.

The objects of the experiments at Henaratgoda are numerous
and have been made pubhc on several occasions. One of them is
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,
(6) 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 equahty in all the physical
conditions, and it is beyond the power of any one to calculate the
individual potentiahties 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 prevailing
at the time of the experiments.

Photo by D. L. Giduiioardane'
TAPPING THE RENEWED BARK AT ELPITIYA.

TIIK FIHST CORTICAl, STRIPPI.V(; (;AVf; 1« r.R. (IK lU'HRKR I.V 1 TKAK.

PARA RUBBER.

1:^1

Comparison of Yields by^ different Svstems of TAinnso.
Base to 5 and 6 feet ; 25 Trees in each Group.

Systems.

Ai'ea excised, in square

inches
Number of times tapped
Yield of dry rubber in lb.
Yield of dry rubber per
5,000 square inches in lb.
Yield of dry rubber per

40 tappings from 25

trees in lb. . .

Full Spiral.

(A)

12,414J .
37 .

m ■

20-49 .

55-0

Half-Spii'al.
(B)

5,003i ..

41 ..

35J ..

34-47 ..

34-20

Full herring-
bone (C)

7, 348 J
39

47 ^

32-55

48 -02

Spiral and Herring-bone Tapping compared.
It is probably unwise to dra^v final conclusions from the above
experiments, as the period occupied for the whole of the work lasted
only about five months and the trees were 15 to 20 years old at the
tim'e of the experiiuent. But care was exercised to equafize, as far
as possible, the physical conditions in the three sections and to avoid
erroneous deductions being made. A synoptical statement 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 haJf-spiral system of tapping. Tliis 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 tlie above results show that the maximum
quantity of rubber p?r tree has been obtained from the full spiral
system,' such a system is to 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. The adoption of this
aystem removes the maximum quantity of bark, in a given time,
and it is, therefore, the best one to adopt in thinning- out estates
which are too closely planted.

On the other hand, it appears tliat the maximum quantity
of rubber for equal areas of bark has been obtained from tlio 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 tap-
ping area.

132 PABA RUBBER.

It should, however, be pointed out that in these experiments

the different systems have been carried out in such a manner that the
paring operations Iiave only removed from IJ to 2] inches of cortex,
along cacli incision, in five months. The tapping lines were
originally 12 inches apart, so tliat the wliole of the area prepared
for tapping will only be worked through once in about two to three
years. If the Para rubber tree is not too seriously injured by
complete cortical stripping once every three years, it seems hkely
that the full spiral system of tapping, though the least economical,
is one which might be adopted in the future on account of
the large yields obtainable thereby.

Yields Obtained at Henaratgoda.

The yioldr. of rubber obtaiiiod from tho oldoi.t troeG m Ceylon
during a period of olovon monthu with alternate piickiiig and
paring were as followa : —

Ko. of times
tapped.

92
270
136

11
171
267

84 F H 15 0

L. S, (Long spiral) ; H. S. (Half spiral) ; F. H. (Full herring bone.)

Tlio Irghor.t yioM of rubbor war. obtained fr-^m troer. tapped
from tho ba;.o to fftyfiot; those h'gh tapping oxpitvirnonts were
m"dlfiod and worked oa r.uoh a plan that tho ylold t')taroi about
1"' lb. of diT rubber por tree iii olo/on moathii; tho-o can bo but
lltt'o doubt that, if no 'oi-.r.ary, at tho r.a'irifico of tho t""00, tlvoe
timop, that amount could b«» ob'lia'no'l within one yoar, Tho c )rtiual
Btripplng necoi-.r.a-y to givo r.u ;h a h'g'i yield, within one yoar
would, ar. wan pointol out at tho Coylo-i Rubbor Exh.b'.tlon, ha all
probability kill tho troo.

"Results of Hinn Tappfn'o at Henaratgoda.

The foregoing results were obtained by tapping selected sides of
trees from the base to five or six feet from the ground. In addition
to these, other experiments were commenced in order to dete mine

System of

rield of di-v rub-

tapp

ing.

ber per tree.

Ih.

oz.

Photo by D. L. GunciwiirdniK .
HALF SPtRAL SYSTEM-

Al-l'KI{ n- MAS (ilVKN 14 I,B. OF UrHIlKK.

PAllA RUBBER. 133

the yield of dry rubber obtainable from different sections of the tree
above the area usually tapped on estates.

RUBBER-YIELDIXa CAPACITY OF DIFFERENT ArEAS.

Base to 50 jeet.

Bas9 to

Oto 10

10 to 20

20 to 30 Base to

Base o

5 & 0 ft.

feot.

feet.

feot. 30 feot

50 feet.

lb.

lb. lb.

lb.

Yield of dry rub-

ber per 5,000

square inches

ot excised baric. 32-55

29-03

22-23

10-45 13-13

5-96

The above results were obtained at Henaratgoda between
September, 1905, and February, 1906, the system of tappincr
adopted being the full herring-bone. In most cases the quahty
of the rubber was good.

These experiments prove most definitely 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 tlie stem.
In the above results one can discern a fairly regular agreement, and
as the figures for parts of the stem as high as fifty feet from the
base have not been given before, the conclusions to be drawn are all
the more interesting. Other results over larger surfaces a'^ree,
more or less, with the above, except that the average yield of
rubber per square foot is often higher than that here given for the
stem between 6 to 16 feet.

Basal tapping only, in the form of a Y, has, during 1907
and 190^, given very good yields in Ceylon and Malaya: in these
operations only the firiit two feet from the basj are tapped.

16 Tappings give 3^ lb. Rubber.

It is of considerable interest to note tliat though the rubber-
yielding capacity of the cortex of the stem gradually decreases from
below upwards, the jaeld of rubber obtainable from the lii/her
parts of single trees, similar to those at Henaratgoda, is often
surprisingly large. The following results show that as much as
3J lb. of rubber may be obtained from one tree in 16 tapping
operations.

Whera tapped.

Number of

times

Yield of Rubber

tapped.

per tree.

6 to 16 feet

, ,

2 lb. 6 », oz.

10 t . 20 feet

^ ,

3 lb 3 oz.

20 to 30 feet

• •

2 lb. 6 oz.

Bade to 30 feot

, ,

4 lb. 6 oz.

Ba*j to 5J feet

^ 8

1 lb. 10 oa

134 PARA RUBBER.

Other trees, tapped at similar levels, show very large but
variable yields.

Average Yielding Capacity of the Cortical Tissues.

The yielding capacity of the Para rubber tree 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 conditions,
per square metre of cortex for certain Para rubber trees in Java. A
laro-e number of results will be required before anything definite can
be asserted, and the following figures should be useful for compari-
son with those of other observers. The experiments were carried
out at Henaratgoda between September 26, 1905, and February 13,
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 exciiied, in Yield of square foot of

square inclios. Rubber. cortex removed.

Base to 5 and 6 ft. .. 1 MH .. 47,^ .. 14-8

6 to 16 feet .. 796^ .. 4| .. 13-37

10 to 20 feet .. 1,472^- .. 6i^, .. 10-26

20 to 30 feet .. 1,424| .. A{1, .. 7-58

Base to 30 feet .. 1,666 .. 4| .. 6-05

Base to 50 feet .. 2,726 .. 34- .. 2-74

The above results show what may, on an average, be expected
by different systems of tapping— s])iral and herring-bone— from
parts of the tree from the base to a height of fifty feet. The trees,
on account of their age, had moderately tlnck })ark tissues, and the
averac^e 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. It remains to be seen what [)roportion of
rubber the remaining and renewed bark will give. In a fairly
('eneral 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, and from such an area an average of about h lb.
of dry rubber may be extracted from the bark of trees younger
than those just dealt with.'

t-i

'<*

1-3

-u

-«1

::^

_j
>

—

<•,

iii

ffl

C-l

PARA RUBBER.

136

Comparison of Yields obtained at Henaratgoda.

The following synopsis is given to bring the results at Henarat-
goda up to datcj the yields from all the systems employed are
included: —

Method (3

Number

Area N

umber of

Total

Yield

tapping.

of Trees

tapped, times tapped.

of Rubber.

tapped.

lb.

Full Spii-al

(A)

.. 25 ..

Base to 66"

. . 57 .

. 71

»t »»

(D)

. . 5 . .

Base to 60"

..168 .

,» ,»

(K)

o . .

Jla.so to 60"

. . 83 .

(V)

5 . .

J, , ,

. . 28 .

<• ,)

(G)

5 . .

,, »•

», ,»

(H)

,~y . .

», »'

..68 .

14|

>• >>

(I)

5 . .

„ „ 62"

..157 .

<• ,,

(P)

1 ..

., ,,30"

. . ?7 .

Half-Spiral

(B)

.. 25 ..

., „ 66"

..60 .

Full herring

bone

(C)

. . 25 . .

„ „ 66"

..57 .

. 72

»,

(M)

2 . .

0 to 16'

. . 45

15J

9 1 99

(X)

10 to 20'

..44

10^

»» 99

(0)

20 to 30'

..44

(L)

1 . .

Base to 30'

..47

,, >'

(W)

2 . .

Base to 50'

..37

The above results were obtained from the 26th September, 1905,
to April, 1906, from trees at Henaratgoda ranging in age from
15 to 20 years. In all cases but Uttle of the available bark was
excised. Further experiments were made on the same trees and
satisfactory' yields obtained ( see page 120 ).
Rubber fegji Shavings.

x\.ccording to .Mr. G. H. Golledge it is estimated, in the Straits,
that the shavings from 100 coolies' w^ork will give about 25 lb. of dry
rubber, but he is incUned to think that the parings to produce this
must be rather thicker than those produced on c aret'ully- worked
estates in Ceylon. Mr. GoUedge's figures are not final, but exper-
ience shows that he can obtain from 100 lb, of shavings some 7 to 8 lb.
of dry rubber by the use of a rubber washing machine, consisting
essentially of two rollers driven at different speeds under a stream
of water. The actual quantity of rubber in the sliavings is small ;
much more is attached to the strips of bark.

Yields in ^Ialaya.

The results obtained by Ridley, Stanley Arden, Deny, and
others have been pubhshed from time to time, and from them the
following synopsis is made. The range in jield 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 weU-f^rown
three- j'ear- old tree. Some trees, having a circumference of 36 inches,
have given 3 lb. of dry rubber per tree ; other trees, 2i inches or more
in circumference, have been known to give only 2;^ oz. of diy rubber
each probably on account of their being too young. The vield

138 PARA RUBBER.

from young troos appears, however, to bo more encouraging when
the latest raothodf. avo acl^ptod. ExcoUont roiiults are iiaiJ to hivo
boon obtained on Lanadron Ei^tato, Johovo, by outtbig a largo V
at a foot tj oightoon in.ihor. from tlio bai;o of tho tvoo,tno V exooni-
ing lialf round tlio tree ; when tho tree in large enough a second V
is, out on the rovenio oido. By such a method tho young trees can
bo tapped regularly — almost every alternate day — the rubber is
extracted only from tho thick part of the bark, and a high yield is
obtained from the basal regions.

An old Para rubber tree at tho S'n'iaporo Botanic Gardens was
tapped in November and December, 19)8, and 4 lb. 4) oz. of dry rub-
ber obtained ; that made a total of 35 lb. 13^ oz. from the t:e3 since it
was first tapped. Tlie tree, which was about twelve years old,
reached tho height of its production in 1905 when 4 lb. 12^ oz. of
rubber was obtained.

The report of Mr. W. Peel, the Agricultural Superintendent of
the Gardens, on the tapping operations during 19 )i, showed that
though the old tree in the Bjtanic Gardens which was tapped 14
times between November 19uh and December 15th, and gave 4 lb.
4.^ oz. of dry rubber, the same number of operations on trees on
Penang Hdl, carried out between July 11th and August <ith,
yielded only from 11^ oz. to 2 lb. 14 oz.

The following results^ are of considerable interest, as they
show the yield obtained by tapping trees of diSerent ages on 12
alternate days by the herring-bone system : —

No. Circumfereac3 3 ft. A?o. Yield-

from ground .

Years.

Ounces

17iia.

1-54

26.^,,

2-26

26^ „

14-27

391 „

8 to9

16-76

10 to 12

28-25

From these and other results Arden concluded that trees und3r
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.
Other results have shown that an average of 3 lb. of rubber per tree
per year, from trees in their 11th to 15th year, may be reasonably
expected.

Two very old trees at Perak.t having a circumference of 56 to 89
inches respectively, and reported to be 25 years old, have given in two
months' tapping no less tha^ 12 and 18 lb. of dry rubber, including
scrap.

* Report upon Jleocj. b.uailienni'i in tho Maia/ Peninsula, Stanley
Arden.

+ ludia-Rubbor Jouraal, February, 19-3.

PARA RUBBER. 137

Otlicr trees at Perak, 14 years old, liave »iven an average yield
of over 4 lb. each, and others of the same age quoted by Johnson show
a yield of 3 lb. 1 oz. per tree in Malacca, and 6-3'^ear-old trees in
Selangor 1 lb. 2 oz. per tree. The figure on one Plate shows
a tree being tapped on the herring-bone system in Malacca.

Carruthers, in his Aimual Report for 1908, gives some tables
which show the development of rubber estates and the yields
obtained on ])roperties in various parts of .Afalaya. The foUnwiuj^-
are extracts fi'om the report : —

Fodoratod Malay

Straits

.Toll ore.

Total.

States.

Sottlements.

No. of troes tapped 44I,48S

•-'7, 070

4s,:r)0

.'■)IG,914

Dry rubber extract od. Lb. S61,7,3-J

13,560

47,724

923,0(51

Carruthers states that the "average amount of dry rubber
extracted per tree, calculated from the figures in the table, gives
1 lb. 12 oz. per tree. Many of the trees iii the Federated Malay
States are 10 years old •" some over 20 years give a good deal more
than 2 lb. a tree.

Dealing witli parts of the Federated Malay States alone,
Carruthers gives the following particulars : —

Federated Malay States.

Selangor. Perak. Nogri Paliang. Total.
Sembilau.

No. of trees tapped. 364,6.38 67,710 91,410 — 441,482

Dry rubber extracted. Lb. 620,033 94,848 146,891 3,645 861,738

The average yield of rubber fi'om trees on a well-known property
in the Federated Malay States was recently published.*

0)1 tliis estate 130 trees 8 years old gave 525 lb. of rubber ; 120
trees 7 to 7J years old gave 250 lb. of rubber; 5,500 trees 6 to 6i-
years old gave 4,041 lb. of diy lubber; and a further 0,000 trees,
5 to 5| years old. gave 1 ,815 pounds of rubber; all the trees were
tapped judicioush' on the herring-bone systeni.

The Sandycroft Rubber Co., in their annual report for 1905,
stated that 4,050 Para rubber trees were tapped during the first por-
tion of the year, and these 4,050 trees were re-tapped 0 months later
together with 5,238 other trees; the dry rubber from these tappings,
totalled 6,979 lb. sheet and 1,823 lb. scrap, or a total of 8,802 lb.
of rubber from 9,288 trees.

In Java, according to Dr. Tronip de Haas, there is a large
variation in the yield of trees of the same age or from equal areas
of bark on the same tree.

* India-Hubber Journal, August, 19n7.

(18)

138 PARA RUBBER.

Rubber Yields est India during 1906.
There are very few records of the yield of rubber in South India,
but in an issue of the Madras Mail information was given
regarding the growth and yield obtained on Hawthorne Estate, She\7--
aroy Hills. On this property the Para rubber is growing among
coffee, at an elevation of 3,000 to 3,500 feet, and in a chmate 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 Para rubber trees, twelve of which were seven years old and
the rest five and six years, were tapped, and an average yield of
^ lb. of dry clean rubber per tree for one month was obtained. An
estimate of 1 to IJ lb. of rubber per tree, per year, was given as tlie
probable yield in the future, based upon the above results. In
conjunction with this it must be remembered that at an elevation
of 2,600 feet in Ceylon, in a relatively dry climate, a yield of 2 lb.
of rubber per tree has been obtained during 1905.

On the Mergui Rubber Plantation, South India, tapping by the
V method was recently carried out, and 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, eacli 6 inches in length, obtained in the morning to be
3-54 c.c. compared with 1*89 c.c. in the evening. Tapping in the
lains was found to give almost double the amount of latex per incis-
ion, 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.

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 1 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 the Para and African trees*
may be compared by consulting the tables given below :—

Hevea brasiliensis
Funtumia elastica

Regarding the yield from FLevea brasiliensis, Johnson remarks
that it must not be taken as a criterion of the anticipated yield

* Johnson's Report on Rubber in the Gold Coast, 1905.

Num'er of
Treed tapp A.

i
1

Age of Trees,
ill years.

... 10

Date of
Tapping

(Nov. 1903

^Dec. 1903

Dec. 1901

Average yield of

Hub' erper tiee.

lb. oz.

•; ] 1 03

0 4

„ 1903

... 0 1

„ 1903

0 4

PARA RUBBER. 139

for (recs of this age cultivated iu 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.

Yields DuRrNo 1906 and 1907 in Ceylon and Malaya.

The difficulty, pointed out elsewhere,* of accurately forecasting
llie yield of rubber obtainable from newly-planted trees in the East
lias always been lecognized, and we are gradually gaining a more
varied knowledge of tlie yielding capacities of the different species
now under cultivation. During 1905 the general idea j)revailed
that the older trees of TIevea brasiliensis might be expected to
yield an average of one pound of dry rubber per tree, per year, but
since then many improvements have been made in tapping knives
and systems of tapping.

We are now in possession of a large number of statistics which
indicate the results obtained by well-known rubber companies ui
Cej'lon and Malaya, during 1906, from trees whicli liad been
previously tajsped or which had just reached the tapping stage.
The yomig trees tapped for the first time in 1906 were from about
15 to 24 inches m circumference, 3 ft from the base ; it is mterestiug
to note that during 1906 the yield was rarely under one pound
per year, and on most properties was nearer one-and-a-half to two
pounds, per tree, per annum.

The following figures, referring to the yield per tree but not
necessarily to the total yield from each estate, are of interest : —

Yield Per Tree, f

Number of Average per

Company. Yield iu lb. trees tapped, tree, per year

19UG

Consolidated Malay ... ;^-2,693 11,348 '2.88
Am^lo American Direct Tea

Trading ... ... 3,281 1,172 2.79

Anglo Malay

(a) ... ... 47,788 28,326 1.68

(b) ... ... 28,697 14,123 2.03

(d) ... ... 8,064 8,240 0.97

Blackwater ... ... 13,033 8,744 1.49

The Kalutara Co. ... ... 8,126 4,379 1.85

Kepitigalla C) ... ... 42,612 21,500 1.98

Pelmadulla ... ... 602 500 1.20

Yatiyantota ... ... 8,790 4,636 1.89

iShelford... ... ... 6,805 9,636 0.70

Sandycroft ... ... 16,178 13,046 1.24

Ledbury ... ... 2,057 3,7.55 0.54

Yataderiya ... ... 8,025 5,947 1.34

Perak ... ... ... 16,327 12,600 1.3)

Bukit Rajah ... ... 118,982 88,341 1.34

[_ Continued over.

* India-Rubber .Journal, August, 1907.

t India-Rubber Journal, July, 1907. t 15 months.

140

I>AllA RUBBER.

Yiiai> Vkh ']luee.— Could.

Cuuipany.

Yield in lb

Vallum bvosa
(a)

(b)

(c)

(d)

(e)
Highlands and Lowlands

(a)

(b)

(c)

Cicely

Kuala Lumpur )

( Year ending JvmeoUth, 19U7) j

Rubber PlantationB

(Year ending June SUtli, 19U7)
Pataling
Asiatics ...
Eastern Produce
Golden Hope
Union Estates
Bertram ...
JJalgownie
Kalumpong Rubber Co.

Number of Average per
trees tapped, tree, per year.

12,765

54,451

6,225

7U,82()
l),(i97

95,333

5,742
38,952
19,U69

1,4>SI

8,045
22,558

2,640

758

19,781

10,642

16,271

4,642

36,301

6,225

70,820
29,113

38,639

807

39,874

8,020

r 5,035

) 3,598

1 1,437

C 9,466

2,000
39,336

5,271
20,735

880
400

16,782
8,(X)(J

14,500

2.75
1.50
1-00
1 .Oo

(!.3l

2.46
7.01
0.97
2.37
1-83
2-33
0-56
3-16

0-75
1-10
1-5

ru8

3-00

rs9

1.2

r.33
1-1

Yield Per Acre.

Ill the reports of some companies tlie yield per tree is not
giv^en, but the total quantity of ruliber from a given acreage
possessing trees of different ages is of hiterest.

Company
Kuala Solangor
Malay States Coft'ee Co.,
J lubber (Jrowors Co.,
Selangor Rubber Co.,
Seremban Est. Rubber Co.,

Total yield
lb.

3,222

10,918

4,370

70,577

62,258

Acreage tap-
ped.

57
144

35
653
412

Yield in lb.
per acre.

96
125
128
151

Total 151,745

1201 Average 125

From tliese figures we learn that a yield of 125 lb. per acre,
per year has been obtained from 1,201 acres.

Total Yields from 1905 to 1'J08.

It is common knowledge that the yields which have been
obtained during the past year from Para rubber estates show
a large increase over previous records. This increase in yield is,
to a large extent, due to the various estates having increased the
number of tappable trees; in some instances, however, an increased
;^'ield per tree has been noted. A few particulars, showing the in-
crease in crops during the year on properties owned by companies
who have made their results public are given below ; in the majority

PARA RUBBER.

141

of instances Para rubber only is referred to, but to a few records tJie
yields from Ficus Elaatica trees have apparentl}^ been added.

Total Yields from Eastern Estates.

Company.

1905.

1906.

1907.

1908.

^TC

~"ib.'~l

lb.

Consolidated Malay

—

32,693

63,590

Highlands and Lowlunds

—

134,285

193,50.")

Labu

—

22,000

—

Batu Ca\e.s

—

3,332

—

Linggi

—

102,000

17,000
(Jan. only)

Anglo Ma' ay

—

100,019
(14mos.)

224,150

47,532
(Two montJis

Vallambrosa (\ ear ending

only)

March 31st)

150,922

204,389
(uptoFeb.only)

P. P. K. Ceylon

4,982

8,305

14,800

—

General Ceylon Rubb3r . .

—

10,574

20,000 (?)

— •

Bukit Rajah (Year ending

—

— ■

—

— •

31st March)

6,811

33,203

118,982

162,000

Ceylon Tea Plantations . .

3,685

7,132

—

Inch Kenneth (Year end-

ing 30th Jime)

—

900

2,006

—

Klanang Produce

—

13,218

10,000
(uptoSept.aOth)

Pataling

25,699

43,310

—

Roseliaugh

45,090

89,594

167,000
res^^imated)

Selangor

29,750

70,577

83,230
(9 months)

—

Yatiyantota

8,212

8,761

5,841

—

Langkat Sumatra

— .

—

1,000

(Jan. only)

F. M. S. Rubber Exports During 1907.
Tlie following are the official figures: —

Export 1907. Export 1906. Increase

Perak.. .. 255,530 .. 149,640 .. 105 890

Selangor .. 1,198,751 .. 681,040 .. 517,711

Negri Sembilan .. 530,004 .. 198,112 .. 331,892

Total

1,984.285

1,028,792

955,493

Yield and Distance Apart of Trees.

For several years planters liave not been able to decide the
question of the best distance in planting, many believing that the
closely-planted trees would yield more per acre than those widely
planted. During 190(3 sonic very good resultn were obtained on

PARA RUBBER.

estates -where the trees were widely planted, and oji closely- planted
properties much difficulty was experienced in thinning-out the
undesirable trees.

Yields ox Vallambrosa Estate.
The following statement of approximate yield from the older
fields belonging to the Vallambrosa Rubber Estate Company was
compiled from the manager's report and presented to tlie public
by the Directors in their Annual Report for 1906 :—

■J!

o
o

Distances trees*
planted apart.

No. of trees
tapped.

No. of times
tapped.

1-1

« 2,

Remarks.

Feet.

lb.

»iO

24X12

4642

127(>."3

/ 1

212i

Planted 1899 (about 150 trees

loO

10X10

< 8000
I 28301

54451

242

363

per acre).

This field WAS i)lautPd through
coffee iu 1898, and thinned-
oiit to 260-270 trees per
acre.

12x10

G225

(5225

155

1.55

Planted 1900. Thinned to

f 10000

07..

70820^

250 trees per acre.

«80

12x10

J t)0820

147

117.'.

Planted from 1899 to 1901.

129113

9097 J

Thinned to 250-270 trees
per acre.

!»30

147101

153358

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 tliere is one block
of trees, 16 acres in extent, containing 807 trees planted 30 by 25
feet. Tliese trees, nine years old, were tapped three times during
1906 and gave 2,500 lb. at the first, 1469 lb. at the second, and
1773 lb. at the third tapping; or a total of 5,742 lb. from 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 Etherington, the distance of 30 by 25 feet
allows 2,250 cubic feet of soil to each tree and an average spread
of foUage of 750 square feet ; under these conditions the food-
producing and absorbing power of each tree must be considerable.

Yields at Singapore.
Ridley and Derry in tlieir Annual report for J 904 published
some figures showing ratio of vield to the size of the tree.

PARA RUBBER. 143

Tlie following taT)le was given : —

Comparativo yield per
inch of girth at 3 ^et
(tilth at 3 feet from groinul. from ground.

Under 'J ft. gii'tli ... ... Under | oz.

From 2 ft. to 2 ft. 0 in. ... ... | o/.

From 2 ft. 6 in. to 3 ft. ... . . Under .', oz.

From 3 ft. to :Ht. (') in. ... ... | oz.

From 3 ft. U m. and over ... ... Over ! oz.

Ridley and Deny believe that the best growing period is
between the 6tli and latli years, during which time trees
may increase from about 24 inches in girth to 60 inches or
more, thus showing an annual increment to growth from 3 to
6 inches. They claim to have shown that trees closely planted
do not make a satisfactoiy increment of growth, and that
the yield of ruliber increases with the size of the tree from under
-| oz. of dry rubber to the inch of girth for small trees to over h oz.
for large ones ; to further empliasize the error of close planting
they have submitted the f oUowmg statements taken from the figures
of their experiments : —

No. of trees Average girth Aggregate Dry

tapped. per tree. girtli. Rubber. Remarks.

ft. in. ft. in, lb. oz.

40 2 3 90 7i IS :}} Tapped

-*0 4 2 83 7:1 25 6 ) IS tunes.

50 19 88 7] 18 8]

15 5 8 85 7 33 8

Cost of Production.
Tlie cost of inoduction on several small estates possessing trees
of diiferent ages, often scattered over a large acreage, is relativelv
liigh, but already there are indications that the latex from old trees
may in the future be harvested and converted into rubber, at a
cost of about Is. to Is. Gd. per lb. of dry rubber. The followmg
details* are of interest, since they show the cost of production on
several properties during 1906 : —

Company. Cost of Production.

Asiatic Rubber and Produce Co. . , Rs. 0'97 cents.

Highlands and Lowlands Co. ... 0"25 ,. (dollar)

Pataling Rubber Estate ... 6-3d.

A'allambrosa ... is/

Vogan ... Rb. 0-90

Yatiyantota ... ls/7id.

Seremban Estate ... Rs. rci

The Kuala Lumpur Rubber Co., Ltd., in their report ending
June, 1907 state that on Wardie-burn the cost of collectino- and
curing was 3114 cents (dollar) per lb. and on Kent 24-4%ents
per lb. The cost of despatch of rubber from the estates to
Europe was 10-4 cents per lb.

India-Rubber Journal, August 26th, I907,

144 PARA RUBBER.

The Balgownie Rubber Estate Co., in their report for tlie year
ending 31st Marcli, 1907, state that the cost for rubber taj^ping
and curing was 7,217 dollars ; the cro|) was 10,642 lb.

Annual Increase in Output from Estates.
The yields obtained from some estates during the past few
years are small but show a gradual increase from the same proper-
ties as the tapped trees get older and more young ones attain a
tappable size and age. The gradual increase is exemplified in the
yields obtained on Gikiyanakanda, Neboda, Ceylon, according to the
information kindly supplied to me by Mr, Golledge, at my request.

G'iktyanakanda.

ield

per tree from

Year.

yuuno'

and old trees.

lb.

lOO.'i

0T>9

1904

0'7G

1905

1'32

190G

1-78

1907

1-86

190S

... 8,1

75 11

). from 1 1,694 trees,

to 4th

A pi

•il.)

{1st Jan.,

Estimate of Yield.

From these and other considerations it is obvious that to offer
an estimate of the yield from trees of known age, one must be conver-
sant with the climate and soil conditions, the available tapping
area, the trees, and the method and care adopted in tapping
operations. The results warrant the conclusion that trees from four
to six years onwards, having a minimum circumference of 20 inches,
may be expected to yield an average of one to three lb. of dry
rubber per tree each j^ear up to their lOtli year, and a higher yield
in subsequent years. The adoption of better systems of tapping,
which obviate the necessity of paring away the tissues wherein the
milk accumulates, and drawing supplies of latex by merely cutting
and not excising the laticiferous tissues, is bound to result in an
increased yield, since the life of the tapi)ing area is so much
prolonged. The fact that a few well-developed trees have been
made to give as much as 12 to 25 lb. of rubber per year, and
])romise abundant yields in the very near future, shows what a
tremendous amount of material there is to di-aw ui)on, providing the
environs of the ]}lant and tapping operations are fully understood.
The heavy yields reported in one part of this chapter are, however,
from exceptional trees, and when forming an estimate of the
average yield over a large acreage inay ])e neglected.

The reader is referred to the details given in tlie present
chapter, showing the yields obtained fi'om Ceylon and Malayan
])roperties during 190.5, 1906, and 1907, and those giving the yield of
rubber per square foot of cortical tissues removed, if he is anxious
to form an estimate of the rubber ol)tainable on an estate where
the availa])l(' tapping area and ))ark thicknesses are known.

CHAPTER XI
EFFECT OF TAPPINd OS THE TREES.

Effect of repetitional bark stripping — ^Danger of annual cortical strip-
]»ing — Excision of Rubber and Ciuclioua cortox — Excision and
Incision — Pricking and paving in Ceylon in 1908 — Effect of tapping
(in the foliar periodicity of the trt^es — Effect of tapping oa size and
number of seeds— Frequent tapping and reduction in yield of rubber
— Frequent tapping and qualitj'^ of rubber — Time interval rociuired for
accumulation and concentration of latex— Reduction in percentage
of caoutchouc in the East — Scliidrowitz and Kayc on an abnormal
atex with low caoutchouc contents — Stevens on caoutchouc, in latex
rom 6 and 7 year old trees — Time interval for matu^'ation of cortex.
— Rate of bark renewal m Ceylon — Rate of renewal on crowded
estates and in inferior soils — Thickness of renewed bark at Gikiyana-
kanda — Thickness of renewed bark, 3, 15 and 36 months oh! —
Tliicknessof renewed bark two years old, at Henaratgoda — Formation
of rubber in. situ.

The Effect of Repetition al Bark Stripping.

IT is common knowledge that many of the excessive yields have
been obtained by completely excising the whole of the bark
tissues from the base up to a heiglit of six to fifteen feet, and it i.'j
natural that some (questions should be put forward as to tlie pro-
bable effect of such treatment on tlie 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, /rom aiove doicmwards , to various sections of
the growing plant, and also to store up, in certain of its cells, a quan-
tity of food as reserve material. As a store liouse and conducting
channelitisof vital importance to tlie 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, frotn 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 renewal on the activity of the
cambium — a delicate tissue separating the inner cortex from the

(19)

146 PARA RUBBER.

wood — and in the natural course of events gradually dry up near the
surface and peel oti" in the form of dead bark. The inner cortex,
originally containing the latex tubes, is therefore ultimately cast o£E
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.

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. Under
these circumstances it may be suggested that the complete strip-
ping of the bark, every year, is a forward but dangerous plan on which
to work. Tlio writer has seen many trees which are not thriving
under such a treatment, and is incUned to recommend it only in
cases where thinning-out of the trees is desired. On many estates
where the parallel tapping lines or areas are originally planned
out twelve inches apart, the bark is excised at the rate of
one inch per month, which means complete stripping in a year ; on
other properties an inch is made to last from two to four months.

Excision and Incision.

If the area is excised at such a rate that the whole of tlie bark
is removed in three 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. Three to four
years i t 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 Para rubber trees in Ceylon; it is a
question whether it would not be better to only 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 in-
cising and not excising the milk tubes.

The effect of paring away the outer bark and exposing the
internal and more delicate structures to atmospheric influences has
in some cases been detrimental. In a particular case in mind

PARA RUBBER 147

the inner tissues dried n\) and peeltnl otV in Hakes, exposing the
whole of tlie wood. This etl'eet is more noticeable on Ceara rubber
trees, but is also known to occur on trees of Para rubber. It has
been suggested that a covering of some waterproof material or of
any substance wliich, while affording protection from rain or sun,
will not hari)our insects, might be used to cover the tapping area
or renewed bark when collecting operations have been completed
The covering might be arranged loo^el}^ in the form of a mantle
or be wound round the oblique excised areas like an ordinary
" puttie"' for one's legs.

Pricking and Pabing in Ceylon in* 1908.

I was agreeably surprised to observe the freiiuency with which
trees were being pricked on the occasion of my visit to several
well-known Kahitara estates in April, 11308. On two plantations,
where a year ago only the paring operation was ad()[)ted, the
juicking implement was used as soon as the ilow following the
l)aring 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 linos 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 there-
by obtained. By such a method great economy in bark is
effected and the risks accompanying the deep paring method are
obviated to a large extent.

Effect of Tapping on the Periodicity of the Tree.

The treatment meted out tc Para rubber trees may be said
to be less drastic than that adopted in rapidly excising or peehng
the bark and cortex off cinchona trees, and not as rigorous as the
cutting off of the stems of cinnamon bushes liear 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 cortical stripping, should bo
recorded.

The most striking effect, even on estates where there has been
but little excision of the cortex and where the latex has been
mahily obtahied by the use of pricking instruments, is that on
the foliar and other periodicities of the plant. 8eve.ral tropical
trees even though they arc growing in the same garden oflvn show

i48 t>ARA RUBBER.

considerable differences in foliar periodicity ; but untapped trees
of Hevea hrasiliensis 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 trees do, however, show mucli variation; the leafless
phase of heavily tapped trees may be passed tlirough during different
months of the year. It has been shown elsewhere that the foUar
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 foliar periodicity is coincident witli changes in Immidity
and it appears quite possible that the extraction of latex, involv-
ing the removal of almost half its weight in water may, from
moisture changes alone, be partly responsible for some of the
clianges in foliar periodicity. If the change was only more general
this conclusion would be mure justifiable ; it is the constancy in
all periodicities of some heavily tapped trees of Hcvea hrasiliensis
which prevents one from making a definite statement on this point.

The changes in foliar periodicity, produced by deliberately
mutilating parts of the tree, are onlj^ too well-known ; probably
much of the change in Hevea hrasiliensis 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
interraption may lead to further irregularities, to a lessening of the
vigour of the plant, and even hastening the decay and premature
death of various parts. Reports have been frequently received
to the effect that the size and number of the seeds produced have
been reduced on some 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.

FREyuBNT Tapping and Yield of Rubber.

That too frequent tapping may lower the yield of rubber
there can be no doubt. It has been previously ])ointcd out* that
results of experiments outlined to determine (luite different points
have shown a common agreement in so far that, when tapping
has been done too tretjuently or too extensively the yield of rubber
has been reduced, and the bark or source of future latex ha.s gone.
Ill some cases the poor yield from well-developed trees cau
be associated with the too rapid excising of the bark, and the
sooner one realises that the bark is really the " mother of rubF)er ",
and that its rapid removal means a reduction in subsequent
yields, the better for all concerned.

* Science of Tani llubber Cultivation; Messrs A. M. & J. Ferguson.
Colombo ; 111" 17.

PARA RUBBER. 149

One might at first conclude that, since the Para mbber 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 fret^uently 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 was 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 whiili were tapped every day (on 2G4
occasions) have given 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 only half of the original bark was removed.
The illustrations will help to make this clear.

I inspected tliese trees in April, 1908 ( about two years after
the experiments ) and was convinced that tapping every day was
extremely dangerous and one likely to materially affect the future
life of the tree.

Tappnig at less frequent intervals did not only give a higher
yield of rubber per tree, within exactly the same period, but there
was sufficient original bark remaining to last for another nine
months on each tree. The labour expenses were reduced ; the yield
increased, and the trees less drastically treated by tapi^ing every
alternate day instead of every day. There is some ground for
believing that, when incision of the latex tubes is made more per-
fect than at present, the interval between each tapping operation
may, with advantage, become still longer and yet be accompanied
mth a further increase in yield and saving of labour. In view of
the enormous variation in the yielding capacity of bark of the
same tree 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 oi-' Quality.
The inferiority of some samples of plantation rubber may
be paitly due to the caoutchouc and other constituents being
immature. Tlie (|uaUty of rubber from the same trees in Ceylon
\a)-ies tVoui time to time. TJie rubber from the first taj^piugs
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' tappmg, be of excellent quahty,
but after a time the (juality often deteriorates. The deterioration
in the rubber obtained after prolonged and repetitional ta})ping of
l)rimary 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 circumstaiices possesses a lower percentage of caoutchouc

160 PARA RUBBER.

and other iu'j;i'cdients and seeing tJiat in tlie ronewed bark all the
constituents liave aiisen within a biief period of one or a few years,
they can hardly be expected to have attained the same degree
of maturity or strengtli, as those in tlie primary bark of older
trees. In the Brazilian and African forests the trees and vmes 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.

Tln^ variation in the characters of the components of latex
is considerable, especially if one considers ditferent aged parts
of the same tree, latex often bemg abundant in the younger parts,
but so constituted as to be uncoagulable. The association of
the strength of the final product with the fre(j[uency of tapping
should be borne in mind and cause planters to hestitate before
tapping too frequently or too rapidly destroying the original bark
during collectmg operations.

Reduction of CAOUTcnouc.

In the discussion following the lecture* given by the writer at
the Ceylon Rubber Exhibition it was pointed out, that the
percentage of the caoutchouc in latex might v iry from 10 to 32,
the latex from trees which had been too frequently tapped usually
possessing a very large proportion of water. The caoutchouc
is derived from comj)ounds which have been identified in various
parts of the plant, but as its production involves a complicated
series of chemical changes, a certain time mterval 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 oujices of latex givijig 9 lb. of rubber, and from the second
tapping, one month afterwards, 433 ounces of latex giving 4 lb.
15 oz. of rubber.

xVbjsokmal Latex feom Ceylon.

Messrs Schidrowitz and Kay e have pointed out, in the " India-
Rul)ber Journar' of July 1st., 1907, that in a sample of Ilevea
hradilieims latex from Ceylon "the amount of rubber contained
was abnormally small. The weight of the crude rubber obtained
from 750 cc. of latex, after pressing, amounted to only 35 grams,
or roughly 4-G per cent. Allowing for moisture, this would mean
that the latex in question contained barely 4 per cent, of dry
rubber. The latex, it may be said, was obtained from the primary

. ♦ Science of Para Rubbei' Caltivatiou, Messrs. A. M. & J. ForgusoU'
Colombo, 1907.

PARA RTTBBER. 151

bark of a five year old tree, tapped in a normal manner, and we
are not m a position to offer an explanation of the exceedinjily
low caoutchouc contents." They do not state, howevei', wiiat
quantity of liquid was added when the latex was first bottled
in Ceylon.

Stevens following on this point states * that he has also
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 weie obtained.''

"The latex was obtained from trees 6 and 7 years old, and
represents either the first or second year's tappings. The
contents 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. 1 am given to understand fhat no water
was at any time added to the latex. The preservatives added
were " cyllin" formaline, mercury salt, and chloroform.

The following figures were obtained : —

PRESERVA'n\^.

YIELD OF .MOIST
CAOUTCHOUC.

Cyllin

500

8.4 p

er cent

>»

1000

8.8

»»

2000

9.2

»»

3000

lo.o

FormaUne

ill

1000

8.6

Mercury salt

2U0U

10.0

>' >»

10,000

9.7

Chloroform

. . 1

13.5

When allowance is made for the moisture, which is
probably not less than 10 per cent., it will be seen that with
one exception the yields were in aU cases less than 10 per cent
reckoned on the orighial latex." In these instances, tlie latices
examined by Messrs Schidrowitz, Kaye and Stevens, do not
appear to have been derived from anj'' specially tapped trees
and may indicate the variability of the composition of the latex
rather than the effect of excessive tapping.

Rate of Bakk Renewal in Ceylon.

The rate at which the bark of tapped trees renews 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 whore 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.

* India-Rubber Journal, London, July 15th, 1907.

152 PARA RUBBER.

()ji 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.

Measurements made in April, 1908, showed that on Gikiyana-
kanda estate, the renewed bark, on a nine-year-old ti-ee grown on
poor soil, was wlien three years old, j\. to ,\ of an inch in thickness.

The following measurements m ere also made on an estate in
the South of Ceylon, in April, 1908:—

Age of

Thickness

Height from

Xature of bark.

renewed

of renewed

ground of

bark.

point of
measurement

Second renewed bark-

2 months.

^^ incli.

Base

Second renewed bark.

15 „ .

8 >>

5| feet.

First renewed bark.

36 ,,

g ,,

."i ' foet.

These measurements were made on a tree, 14 years old, with
a girth of 71 inches ''a yard from the ground. The remnants 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 orginal. The tree has given 15 lb. of rubber in 4 years.

Another tree 4| years old, had its renewed bark jV' ^^ 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 I, ^, f , and 5, of an inch respectively, in thickness.

The bark renews fairly rapidly on the majority of the trees
but the latex takes longer to mature.

Formation of Rubber in Situ.
No one has yet determined the total quantity of rubber
procurable from the whole of the bark of a Para rubber tree of
known age or size by felling the tree and maceiating the milky
tissues. But it is well-known that, irregularly connected though the
latic fers in this species may be, the quantity of rubber procurable
by tapping may greatly exceed the actual weight of bark removed
even when a wasteful excision method is adopted. It is therefore
obvious tliat the rubber must be formed in • he bark in virtue of
the associations of the laticifers with other parts of the plant which
permit of tbe circulation of ingredients ultimately forming part
of the latex. The laticifers in the bark are usually sunounded 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.

PARA RUBBER, \r>:)

Wlu'Mover latii^ifers arc cut it. is obvious tliat they must
partially drain those with whicli tliey are connected and, after
(^h^sinii;, aji;ain become filled partly witli 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 foiin laticifers in the second-
ary cortex.

In order to determine whethei- caoutchouc is developed at
the place where it is collected from the tree, experiments are
now being made (Tropical Agriculturist, September, 1907) ; " 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 he avvaite:! with
interest. In April, 190S, the isolated cylinders of bark possessed
a fail' ((uantity of latex.

a«(K»%^S^^»*—

(20)

CHAPTER XII., ^
PHYSICAL AND CHEMICAL PROPERTIES OF LATEX.

Physical ]5roperti('S of latex — Colovir, consistency, alkalinity— Sap
exudations and acidity — Object of producer — Meclianical im-
purities—Water in latex — Chemical Analyses of latex of Para
rubber by Seeligmann, Scott and Bamber — Variation in Chemical
composition — Caoutcliouc globules — Occurrence, size, density and
lircwnian movements — The origin of caoutchouc in ])lants —
Resins and Sugary substances ui latex — Protein matter in latex
and putrefaction — Mineral substances in latex and their influence
in coagulation — Specific gravity of latex — Gt-nerul cliaracters of
latex — Effect of temperature, ammonia, formalin and acids.

The Physical Properties of Latex.

rpHE latex of Hevea brasiliensis , as it flows from a freshly made
X incision, is white or pale yellow in colour, and varies in consia-
tency mainly according to whet her drought or rainy weather prevails.
It is slightly alkaline when fresh, and, as it flows from the tree, con-
sists of minute globules of caoutchouc and other bodies suspended
in a liquid containing various materials in solution and a varying pro-
portion of mechanical impurities.

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.

The object of the producer in the Tropics is to separate the
globules of caout<;houc from the mechanical impurities and some of
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 maiuifacture from latex, must thoroughly grasp the
nature of the substances he has to deal with.

PARA RUBBER. 155

The meclianical 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, caoutchouc,
resins, proteins, sugars, gums, insoluble substances, and mineral
matter. The amount of water in pure latex varies con.'^iderably,
but it i>"> usually estimated at 50 to 56 per cent. Tlie 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 percent, of water is present. The latex
collected during the dry months of February and March at
Henaratgoda contains much less water than tliat obtained from
the same trees in the rairry season. The following table will
serve to indicate the general range m composition according to
the analyses of Seeligmann,* Lascelles Scott, and Ba ruber j:^

Chemical Analyses of the Latex of Hevea Brasiliensis

Seeligmann.

Scott.

Bamber.

per cent.

Water . . .. 55 to 56

. . 52-32 .

55'15

55 "56

Caoutchouc or india-

rubber . . . . 32 .

. . 37-13 .

. 41-29

32-00

Protein or albuminous

matter . . . . 2-3

2-71 .

2- 18

2-03

Re«in . . . . Traces

3-44

—

2-03

Ash

0-23 .

0-41

Sugar

4-17 .

0-3G

Salts

Essential Oils . . 9-7

. Traces

Tlie above arralyses show the general composition of the latex of
Hevea bra-silirnsifi and the different classifications adopted by chem-
ists. The analysis by Ijascelles Scott is oire of a latex of unnamed
origin, but Weber accej^ts it as being not far from tlic truth for our
species. There is an indefiniterress about several of the constituents,
grouped urrder such general heads tis proteins, resins, etc.

Tlie latex from parts of the same tree at different times of the
year shows considerable variation, and mhior higrcdients. which
are rrormally absent, appear on certain occassions. It has also
been shown elsewhere how the compositiorr and character of the
latex varies from the same tree during different parts of the same

* India Rubber and Gutta Percha, by Falconet, Setligmaiui. and
Toirilhoui, 1903, p. 84.

t Bamber, Circular U. B. C, June, 1899; and Ccylun Rubber
J^xhibitiuu.

156 PARA RUBBER.

season, according to the frequency of tapping, conditions of
humidity, and tlie age of the cortex whence the latex is extracted.
Schidrowitz, Kaye, and Stevens have shown how certain samples
of latex from trees of Hcvea 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.

It will be noticed that the caoutchouc, according to the above
analyses, varies from 32 to over 41 per cent., and the other constit-
uents such as resin, sugar, insoluble substances and ash siiow
considerable variation. This is not surprising, as the latex examined
in each case was obtained from a different country and the ages of
the trees were probably Cjuite different. Furthermore, the methods
of extiaction of the latex involve the cuttuig of bark tissues to
different depths, and the inevitable mixing of liquids would
account for much variation in the soluble impurities.

Caoutchouc Globules.
The caoutchouc exists as globules in suspension. When pure it' is
practically colourless, and is mucli lighter than water. It consists
essentially of carbon and hydrogen, and belongs to a class of bodies
known as terpenes. It is insoluble in water, but, according to
Weber, may be obtained fairly pure by making a benzene solution,
allowing the insoluble luatter to settle out, and subsequently precipi-
tating the rubber from the clear solution by the addition of alcohol.

The caoutchouc globules oUIrvm 6m.sj7?Vw5i6' vary considerably
n size; their dcjisity varies from <)-914 to 0-98(), at 16° C.

Henri states that microscopic examijiation of the latex reveals
the pretence of a large number of globules some with a diameter of
nearly 0-002 milliiiieties, otheis smaller, the latter exhibiting
r.xtremely iiiteuse nnd iiersisteut BroAvniaji juovenumts. The
iiunil (M- of globules in a latex indicates its richness and may bo easily
(loteuniued : in the ojjoration a suitable diluent— 20 ])er cent.
^(>lution of sodium chloride— is added, whirli arrests tJie Krownian
iiiovemejits. witiu>ut j)recipitating or coagulating the latex; the
globules can then hv. counted and in one case aji average of 50
millioji globules ])er cubic millimetre was counted.

Origin- of Caoutchouc.
The produi'tion (»f caoutchouc in latex has been uivestigated
and it is generally admitted that Harries has fairly well estabUshed
the relation of the caoutchouc to the sugar-like i)roducts— hevulinic
acid— in tiie ])lants ; this is a subject which might well occupy tlio
atlention of clicmisLs in the tropics who have uiUiniited sui>plios of
fresh latex and laticiferous i»lants at their command.

PABA RUBBER. 157

Resins and Sugary Substances.

The irsins, gums, and oil siil)statK'es are preseut in varying
• iuautil.ie«. (.iencially the hitex from young trees, branches, and
twigs contains a large proportion of these substances ; they may
occur as globules suspended in the latex or in solution. In the
ordinary ])rocesse.s of coagulation the greater part of the resin
becomes part and parcel of tlie rubber, and the extraction from the
latter by tiic manufacturers in Europe is a difficult and tedious task.

The sugars are rarely present in large proportioiLS, and a
maximum of 0*5 ])er cent, may be taken as correct. They are
kno\vn as inositc,* borncsite, matezite, and dambinite, and are
tlissolved in the liquid in which the globules of caoutchouc and
resins are suspended ; in the .vashing of the freshly-coagulated
rubber they are generally removed.

I'ROTEIN 3IaTTER.

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
lU'cbably quite diifereiit froju tlie complex proteins which are
coagulated and form pait oi ordinary raw rubber. Spence states f
that though the nitrogenous products which occur in the latex after
coagulation arc peculiar in origin and constitution they are in all
probability simple products of protein metabolism.

The proteui or albuminous matter, about which more will
be said, varies from 1"0 to 2*7 per cent, of the fresh latex, or
approximately 3 to 4 per cent, of the dried coagulated product.
This is a very liigh proportion, but from the analyses quoted above
no other conclusion can be drawn. It is believed that this
protein matter is of a complex nature, and, alone or with the gums
and sugars, is responsible for the development of bacteiia on the
finished product, which lead to putrefaction or " tackiness.'"
The use of formaldehyde in comiection with the elimination of the
protein matter will be considered when dealing witli coagulation.

When the rubber is prepared by simple coagulation the insoluble
pjotein becomes a part of the rubber, l)ut if a centrifugal metliod is
adopted, and tlie freshly-coagulated material frequently 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 the pro-
tein from commercial rubber, though perhaps desired, is almost
impossible, and in the perfecting of mechanical processes and the use

* Weber, /. c, p. 2.

i India-Rubbor Jounial. August IGlh. 10U7: and Quarter)} Journal of
tho Liverpool Uiiiveraity,

158 PARA RUBBER.

of antiseptic reagents for dealing with the protein in the latex as it
comes from the tree lies a considerable amount of important profit-
able work for planters in the Tropics.

Mineral Matter.

TJie morgauic matter found in most latioes consists of
compounds containing calcium, potassium, iron, sodium, and
magnesium ; these are combined with mineral or organic acids.
The concentration and natm-e 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 import-
ance, and can be better dealt with in the sections concerned with the
components of commercial rubber and the purification processes.

Specific Gravity of Latex.
The chemical composition of latex varies considerably and a
difi'erence in specific gravity is therefore to be expected. Muspratt
aives the density at 1'012 ; Ule quotes l-Oll; Henri 0*973 ; Seeligmaim
r019; while Bamber states that the specific weight of latex of
Flevea hradUenms containing 32 per cent, of caoutchouc is TOIS at
()0 F. The density of the caoutchouc itself varies though the
dift'erences observable in that compound are insignificant when
compared with those of the mineral, protein, or resinous contents.

General Characters.
Tlie 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 chamlxu- for days witliout sliowing any signs of creaming.
It is very difficult to separate the eaout(;li()UC by centrifugal force
a)Kl on several occlusions a speed of over l(>,0(K,) revolutions per min-
ute did not elfect a separation of tlie caoutchouc of normal latex. The
effect of freezing was tried by Parkin, a mixture of ice and common
salt beiny used to give the low temperature ; after thawing, the latex
nppeared to be the same as before, and creaming was not hastened
by the el\anges of tempeiature. Addition of ammoiua or formalin
picvcnts or delays congiilation, the former by neutralizuig the acids
as =»oon as they are formed, and the latter by acting jus an antiseptic
and preventing tlie decomposition of the protein matter. Acids
hrini^ about coagulation in the cold, but the action is much (piickcr
wlien warmed, 'i'lie latex nuiy, lio\v(n-er, if diluted, be boiled and
yet coagulation is not brought about.

These points should be boine in mind by the planter who is in-
clined to experiment mechanically and chemically with the object
of extracting the undesirable substances usually present m latex.

CHAPTER XIII.
THE PRODUCTION OF RUBBER FROM LATE'K.

Strainmg latex — Use of porous cloth and centrifugal nmchino?!—
Not largely used in Ceylon — Dt>sf;ri]ition of centrifugal iiiacliiuos
in Ceylon — The phouonienou of coagulation — Hohaviour of latex
from difft'ient speci<^s— The Tlieory of coagulation — Henri's work

Phases of coagulation— Effect of reagents on latex— 'i'orrey on

the structure of cmde rul^ber — Proteins and coagulation— t)pinion>
of Dimstan, Spence and Weber— Proteins and Funtumia latex-
Natural coagulation— Artificial methods of coagulation— Sjion-
taneous coagulation— Natural heat— Addition of water— Addition
of plant juices — Smoking and coagulation — Nati\e method in
Brazil— Palm nuts and plants to use m smoking— Patent sine king
processes by Kerckhove, Brown & Davidson, Macadam, Wickham
and Da Costa— Use of alcoholic solution and creosote— Coagula-
tion by chemical reagents — Use of acetic, formic and tannic acid
* —Mercuric chloride— Cream of tartar— Amount of acetic acid
to be used— Amomits used on Culloden and Gikiyanakanda

Time required for coagulation — Method of determining the

amount of acetic acid required— Advantages and disadvantages
of adding chemicals to the latex— Influence of coagulant on
strength of rubber— Physical properties of rubber prepared by
various methods— Relation of elastic properties to structure
of the coagulum — Observations by Henri, Spence and Torrey—
Components of coagulated rubber— Putrefaction roud tacky rubber
— AmUyses of sound and tacky rubber by Bamber— Use of
antiseptics— The necessity for wasliing rubber— Removal of the
proteins from latex— Ex i^eriments with Ca^tiUoa— Expei-iments
with Para rubber latex — Uses of ammonia and formaliti — Rapid
coagulation and removal of proteins by mechanical means —
Biff en's centrifugal machine — Experimeiits in Ceylon — Aktiebolaget
Separator — Michie-Golledge machine — Matthieu's apparatus-
Harvey's coagulator — Coagulation in the field or factory.

AVING briefly described the physical and chemical properties of
^^ latex as it is obtained in tlie field, it now remains for us to
consider the operations upon which the production of good rubberfrom
latex depends. 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 reagents or 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.

160 PARA RUBBER.

In tho production of rubber from latex the planter may either
take advantage of the presence of coagualable constituents in tho
latex or adopt chemical and mechanical means for the separation
of the caoutchouc globules from the rest of the latex.

Straining Latex : Centrifugal Machines.

But before any steps are taken to effect coagulation the
])lanter should see that the latex is quite free from any mechanical
impurities ; it is first necessary to filter the latex through porous
cloth or remove the visible impurities by means of some
mechanical apjiaratus. At the Ceylon Rubber Exhibition two
centrifugal machines were exhibited for this work and the following
is the account of Mr. Hyde 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 lighter impurities can bo
removed, whilst with the other type only those particles of sand
and gi'it 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 jierforated 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 machmes, but is permitted to find
its proper centre of rotation by the use of elastic bearings, thus
reducing the power required to drive the machine to a minimum,
as also the amount of vibration transmitted to the casing of the
machine. The vertical shaft is driven at the rate of three
t iiousand 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 drivmg. The lubrication of the swing l)ush bear-
ings of the countershaft, as well as in the bearings in the machine
proper, are most efficient, the foruier being self-oiling and the
latter being fed from an oil cup and tube outside of the casmg
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 l)v 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 tlie centre of tho revolving basket or perforated drum.

PARA RUBBRR. 101

Inside tlie latter is placed a linen <»!■ cloth bag, and it is Mirough
this that th«^ latex is rapidly strained leaving the lighter and large
impurities l)e]iind it. The strained latex then passes into the
outer casing and iinally issues from the pij)e at the side into a
receptacle below. By this means large quantities of lat<ix i-an
be strained in a very short titno.

"The machine takes al)0ut 1 Ff. p. to drive, and its output
is 50 gallons per hour. ""

The writer was informed, when at Culloden in A])ril, VM)X.
that the machine, tliough useful, had not been much used by Mr.
Maca tain — or any other ])lanters in Ceylon

"The machine shown by Mr. Kelway Bamber is mucli tne
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 n the same
manner as that described in the other machine, except that it has
to be very carefull}- 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.

Phenomenon of Coagulation.

The physical and chemical changes involved m 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
the rubber from the latex, since this is accomplished by simply
allowing the latex to stand in a receptacle, in the open. The
writer is of the opinion, however, that the methods adopted on
Kastern estates still leave much to be desired and if a better
knowledge of the changes incurred, duruig coagulation, can be
gained, planters of an inventive frame of mind will (juickly effect
improvements; for these reasons it is proposed to study the
phenomenon of coagulation in some detail, and to consider latices
from species other than Hevea brasiliensis.

The latices from different species possess varying quantities of
resms, proteins, caoutchouc and inorganic substances, but the behav-
iour of these to the same agencies — heat, moisture, centrifugal force,
preservatives, acids, and alkalies — is widely different; the phases
of coagulation of latices from distinct botanical sources require

(21 )

162 PARA RUBBER.

separate and deiailod investigation. Heat, thougli it coagulates
many latices, has no such effect on that of Hevra hmsiliensis;
I'ornuildehyde thougli acting as an anti-coagulant with Hevea latex
appears to coagulate other latices; alkalies which help to main-
tain some latices in a liquid condition hasten the coagulation of
others; mechanical means while allowing one to ettectiv^ely separate
large-sized caoutchouc globules from some latices are almost
useless when deaUng with the latex of Hevea hra^^ih'en'^is.

The Theory of Coagulation.
The changes which take place during coagulation have been
variously explained , some authorities contend that heat alone
softens the caoutchouc globules and thus allows them to iniite ;
others maintaui that a film of protein matter around each caout-
cltouc globule becomes coagulated and encloses the rubber
particles which then form an agglutinated mass : many believe that
coagulation can be easily ett'ected in the absence of any protein
substances. The term "coagulation" was, according to Spence,
originally applied to the coagulation of the protein, but it is now
generally used to denote the separation of the caoutchouc globules
and all tliose processes which lead to the pi-oduction of a mass of
rubber from latex. When some latices are allowed to stand, the
caoutchouc iilobules readily agglutinate, when they rise to tlie sur-
face; the cream thus secured is then coagulated by pressure. When
the latex of Hevea hrasiliensis is treated with dilute acetic acid the
caoutchouc does not cream and then coagulate; the latex,
according to Bamber, coagulates throughout its mass, thus includ-
ing much protein and suspended matter, and by its own elastic
force then contracts towards the surface of tlie liquid, expressing
a clear watery fluid still containing protein matter in solution.

Henri,* who carried out a series of experiments with the latex
of Hevea hrasiliensis, pointed out that in connection with the
coagulation of latex there exists a series of bodies which readily
cause coagulation in some, 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,! " tliat the
latex is a suspension of very fine particles in atpieous licjuid more
or less rich in saline or organic bodies. When coagulation occurs
the rubber globules unite,"

Phases of Coagulation.

As the result of his experiments with dialysed latex Henri
concluded that "On adding different reagents to the latex one of
three things may occur : —

1. There is no reaction.

* Le Caoutchouc et la (Jutta Percha, May l.jth, 1907.
t India-Hubber Journal, August I'Jtli, 1907.

PARA RUBBER. 163

2. Isolated flakes, varying in size, are formed which either rise
or sink, but do not unite, beinjz readily separated by stirring.
This may be termed tlie 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
soUd elastic coagulum. This is the true coagulation of the latex."

Effect of Reagents on Latex.
Henri determined the effect of a large number of reagents on tiio
dialysed latex, both inchvidually and mixed, with the following
results • —

"Methyl, ethyl and amyl alcohol, produced no reaction.
Hitherto alcohol has been considered a coagulant, but its action
evidently is due to salts present in the latex. .Sodium, potassium,
and ammonium salts also have no effect. 8alts of calcium, barium
and magnesium in sufticient quantities cause agglutination. Hydro-
chloric, 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."

''Regarduig the action of mixtures, a>s a rule alcohol added
after a salt produces agglutination or coagulation. On studying
the influence of alkalies on the coagulation of the latex it was
found that an extremely small (juantity interfered with the
reaction; a tenthousandth 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 verj' slightly alkaline, only isolated
flakes are formed, again showing that the par.sage from
agglutmation to coagulation is gradual, and that one may be
considered as a higher stage of the other."

The foregoing are very long extracts from V. Henri's work
but in view of the importance of his observations, and
especially those showuig that the final strength of rubber
may be largely determined by the nature of the coagulant used — a
point confirmed by Spence and others — full publicity is given
to the results obtained.

Stbucture of Crude Rubber.

Dr. J. Torrey, in his contribution * entitled ''Xotc on the
Physical Structure of Crude Rubbcj- " points out that Henri
gives a series of plates showing the structure of the rubber
obtained by coagulation of the latex with different leagents,
and shows thai the sajuc latex yields products of totally different
character (as to length of fibre, elasticity and life) according to

* ludiallubber Journal, Nuvctubui-, i'Ji'T.

164 PARA RUBBER.

the reagent by wliicli 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 whicli 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 naptha
solutions of a number of crude unwashed rubbers gave
characteristic figures when a few drops were allowed to evaporate
on a white surface. The solutions consisted of 5 grams of each
rubber in 100 cc, petroleum naptha 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
Kassai, Upper Congo Ball, Ikelemba and Bussira. "

' ' Fine Para gave always a fine regular lace-like pattei'n;
Matto Grosso gave a very similar one, but not so fine and not
KO 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 spols, sliading away very gradually
toward the edges, and (Miunected by a few ratlier faint filaments
which were usually disposed betweeji the tv\o spots in the form of
a single mesh of a coarse netwoik^ — the mesli being approximately
circular in form. The most chaacteristic case of this kind
was Lapori. On the whole, the difterence between the figures
corresponding to different rubbers was so great that even an
untrained observer could, without dfhculty, identify almost any
one of the varieties under examination by its figure."

Pkoteins and Coagulation.

Dunstan * lias pointed out that the original view taken of
the process of coagulation — to the eft'ect that it Avas dependent
upon protein coagulation and the separated ])roteins carrying
the rubber globules with them — cannot be now accepted. Dunstan
states that "There are peculiarities connected with the
coaculation 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 jiiobahility it is the result
(.)f the polymerisation of a li(|uid which is held in suspension
in the latex and on polymerisation changes into the solid
i.(illf)i(l which we know as caoutchouc. There is little room
lor doubt, that the (coagulation is due to the 'condensation'
or polynieiisation of a liquid contained in tho latex. What
is tho nature of this lif^uid from which caoutchouc is formed?"

* Somr IinperJMl As|tucts of .Applied Choiuistry ; Jhill. Imp. lust:
WA. W, No 4., lyOti.

PARA RUBBER. 166

Proteins and Funtumia Latex.

Spence * carrietl out experiments with the objeot of cletei mining
tlie efifect of digesting the latex under suitable conditions with
various ferments; reimet, trypsin, and pepsin were used "in the
hope that by decomposing the proteins or such like bodies into
simple derivatives coagulation may be effected." Negative results
only were, however, obtained. Spence concluded from the results
of his work with Funtumia eUistica latex '' that there are present in
the latex nitrogenous sul)stances capable of digestion by trypsin
into simpler complexes, without at the same time bringing about
coagulation of the caoutcliouc, so that further experimental
evidence is still required before these protein- like bodies, as
Weber suggested, can be regarded as the all-important factor
in connection with latex coagulation. The evidence brought
forward l^j^ him for the existence of a film of jirotein suri'ounding
each caoutchouc globule is ton incomplete, and unless the protein
forming this film is c^f quite a different nature fiom that which
is acted on by the ferment iu the above experiments, it is difficult
to conceive how the destruction of this fihn should not result
in the immediate polymerisation of the liquid contents of each
globule with the formation of a solid coagulum of caoutchou('.
The action of trypsin and pepsin on latex must be further investi-
gated, however, before far-reaching conclusions in regard to the
condition of the protein-matter in latex can be drawii. The
present results are suggestive, however, and in view of the recent
work of Victor Henri on the coagulation of latex, I am now
inclined to believe that the condition of the caoutchouc globule
in the latex in general is maintained, not as Weber supposed by
the presence of a protein sheatli (although it ma}'^ be possible that
the physical state of the caoutchouc particles is not the same in
all latices), but in viitue of the negative electric charge on the
colloid aggregate opposing the surface tension of the particles.
When agglutination (and coagulation) is produced by any means
it is due to the disturbance of the ei^uilibrium between these
forces, and not to the presence of a film of protein matter which,
becoming coagulated, brings down the caoutcliouc with it."
Having touched upon tiie gcneial changes associated with the pro-
cesses of agglutination and coagulation we can. proceed to consider
the purely practical methods adopted in rubber-growing areas.

Natural CoA(;UL.vrioN.
If latex is allowed to stand exposed to air coagulaticui takes
[tlai-e after an interval of from G to 24 hours, 'i'lie coagulated
sul)s(Hnrr carries, or bet-omcs mixed with, the suspended globules
of caoutcliouc and other bodies, so that the whole process is
more or less one of clarification, the liquid left behind usually

IndiaKubbcr Journal, Septombor 1907.

166 PARA RUBBER.

containing only those nigredients of the latex which have remained
in solution. Coagulation occurs as soon as the latex becomes
neutral or faintly acid, no matter wliat proportion of suspended
globules of caoutchouc or other constituents may be present in
the latex.

Buigess states tliat the natural method of coagulation is
only possible where a washing machine is used, and suggests that where
the latter is in use the latex might be allowed to stand for 24 or 36
hours, and the natural fermentation allowed to take place and
produce coagulation. It is difficult to understand this contention, if
by a washing machine is meant one similar to that recommended by
the same authority for the manufacture of cre])e rubber in Malaya — ■
indeed, if it were so it would constitute a serious disadvantage to the
method of coagvdation by natural means. As a matter of fact, bis-
cuit and sheet rubber can be prepared by the natural and artificial
methods with equal ease, without the use of any machinery beyond
an ordinary mangle and a blocking apparatus

On estates where the daily quantity of latex is small the use of
chemicals and machinery for rapidly coagulating it is not always
necessary; the latex is put in shallow pans and allowed to set.
The biscuits or sheets, when ready, are rolled to squeeze the water
out and then placed %on wire gauze, wooden, or coir shelves to
drv. A strong current of dry air might be obtained by drawing the
air by means of a fan through a chamber containing chemicals such as
freshly-burnt lime or calcium chloride, which would absorb the water.
It should not be difficult to arrange a building on a plan somewhat
similar to the tea-diying and cacao-curing rooms ui common use in
Ceylon; in fact many such buildings are used for drying the rubber
on well-known estates in that island.

Artificial Methods of Coagulation.

8ome kinds of latex can be heated for a long time — almost
indefinitely — v.'ithout coagulation being effected, whereas other kinds
coagulate rapidly on the apphcation of heat.

According to Parkin the diluted latex of Para rubber is unaffect-
ed by boiling. If the undiluted latex is lioiled, water is driven off,
and the thickened milk may then become chaii'cd. The separation
of the caoutchouc of Castilloa. I^'icus and Landolphia latices is
often effected by boiling on a slow fire.

The addition of certain chemical reagents to the heated latex
brings about coagulation; dilute mineral acids, acetic acid, and
tannic acid are particularly active.

There are numerous mechanical and chemical processes by
means of which rubber can be obtained from latex.

Until the various theories outlined elsewhere ha\e been
definitely proved and accepted, we can best regard— in a work
such as this which is written for the guidance of the practical

Photo by C. H. Kerr.
LATEX IN SETTING OR COAGULATING PANS

PARA RCJBBER. 167

planter — iioine oi tlie protein substances as playing an
ijnportant part in ooagulaiioii. Certain proteins remain in solu-
tion even after coagulation ; others are (iapable of being couveited
into an insoluble form and occur in all rubbers,

Spontaneoits Coagulation.

In some countries the latex is allowed to coagulate along
the lapping lines, exposure to air being the only desideratum; a
large part of the latex from I/cvca hra-si/iciisis is thus coag\ilated.
The latex fiom Laudolphia vines, Manihot and Sa])iiim trees, is
never collected in the liquid state l)ut is often spontaneously
converted into rubber on exposure to air.

Natural Heat

Explorers who have visited American and African rubber-
producing areas report that the natives frequently collect the
latex and rub it over their anns and chests aiul allow the heat
of the body and the feebly acid perspiiation to aid in the ])roduc-
tion of rubbei-. 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 where the caoutchouc globules are very small and light,
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 elaslica 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 hrasiliensU. 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 and may yet be associated with
the principles outlined by Henri. In parts of tro])ical America
and Africa the.se reagents 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, liave an acid reaction. There are a few
which are said to have an alkaline reaction.

168 PARA RUBBER.

According to Junielle, the natives in Frencli Soucian use
four liquids for coagulating Landolphia Heudeloiii, A. DC; (1)
jiiioe of citron, mad'- by crusliing ten fruits, to a litre of water;
(2) water acidulated with the fruit of AdanHoniti (li<jilata, L.,
one ripe, macerated fruit being sufficient for one litre of water;
{ 3 ) water acidulated by the leaves or calyces of the Rozelle plant -
Hibiscus Sahrlarif/a, Lin. — 500 grams of leaves and fruits being
used in one litre of water; (4^ infusion of fruits of Tamarindus
indica, L., 2 handfuls of fruits being required for one litre of
water. i'lll these plants are abundantly distributed and culti-
vated in many paits of the tropics and can easily be tried by
planters. In Ecuador and the Belgian Congo, the juice from
tlie stalks of "bossanga" — Gostus Liikanuslanu<;^ K. Sch., — is
hugely used as a coagulant. The watery extract from the
macerated stalks of Calonyction spe.ciosuvi, (■hoisy, — which,
according to Preuss is alkaline in reaction— is also used in Ecuador
and Central America gejierally. Another plant which has received
considerable attention as a source of an effective coagulant is
Bauhinia rotwnlata, a species now established in most of the
J-Jotanic gardens throughout the tropical world. It is largely used
in the pioduction of rubber from the latex of Funlumia elastica.
According to Mouutmori-es * a handful of the gieen leaves and
the young shoots is placed in two gallons of water, and boiled
for about fifteen nunutes, the filtered infusion being poured,
while hot, into about one and a half gallons of fresh late.K.

It is obvious that aqueous extracts of ])arts of plants such
as those mentioned above may contain a number of useless as
well as useful ingredients ; it is therefore difficult to ascribe
tlnr good physical properties of the coagulated rubber to any
definite substance or substances until the points have been
chemically mvestigated. The plants used for this purpose are
among those most commonly met with in tropical areas, and
the subject is therefore one which should an-est the attention of
;ill 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 coag-
ulated 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 absoibed, the lat-

* VisciMUit MouiitiiK .ncs. Quarterly Journal ««f tin- bivoriiool
University, 1907.

.PARA RUBBER. 109

ter acting as an antiseptic in preventing the rapid decomposition of
the albuminoids present.

The Amazon- Method.
In Brazil the latex is jjoured into a shallow basin 60 cm. to 1
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 elnta,
All., or with palm nwUivomAttalea excelsa, Mart., and M ax imiliana
rcgia, Mart; these i)alms are u.sually grown in Botanic (Jardens
in various parts of tlie Tropics, the latter species beins more
commonly kno\^ni as the '-Cocurito" palm. A chatty, open at
both ends, is placed on the fire and the smoke allowed to issue
from the upper aperture.

A paddle-hke 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 U hour by these means. The same principle
is said to be adopted iu parts of the Cons:o, in the preparation of
Landolphia rubber. The decomposition of the albuminous sub-
stances in tlie rubber may be prevented by the addition of suitable
antiseptic reagents to the latex, when the rubber is prepared in
other ways, though quickness in drying or complete extraction of
the moisture from coagulated rubber is often sufficient to brin<'
about the same result. °

Patent Smoking Processes.
G. van den Kerckhove has patented an apparatus called the
"Fuiyero" designed for use on plantations where the smokinc^
of rubber is desired. °

Tlie "rumero"is about 80 centimetres in height, can
be transported by hand from one place to anolher, 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 tii? form of sheets, biscuits
balls, etc. It was explauied by the writer at tlie Ceylon Rubber
Exhibition that hot smoke, from smouldering logs of wood wJiich
had been preWously steeped in creosote, brought about coa<ru-
lation of the latex through which it was passed. *

Brown and Davidson's Process.

Another method was, at the time of the Ceylon Rubber Exhi -

bition, brouglit forward by :Messrs Brown and Davidson. Thev

exhdjited an apparatus which was described as follows by Mr

Or. H. M. Hyde in the Official Account of the Exhibition :— " The

* Juraelle, /. c.

( 22 )

170 PARA RUBBER.

apparatus consists of a fireplace in wliicli wood soaked in creosote
is allowed to smoulder ; from tlience the smoke passes along a
flue or pipe connected to the bottom of a sheet iron annular
column about 6 feet in height and from 3 to 4 feet in diameter.
The inner column is a closed sheet iron cylinder finished off at
the head in a conical form and surmounted with a funnel ; on
the other hand, the outer casing is made in two lialves hinged
togetlier like doors. The whole height of the annular column, that
is, the space between the two cylinders, is baffled by means of a
series of circumferential plates or rings inclined downwards. These
plates are rivetted to each of the cylinders alternately, thus
forming a complete series of baffle plates. The head of the
annular space is fitted with sliding doors which are easily adjusted
in order to allow for the egress of smoke or admission of air."

"The working of the machme is thus: the fresh latex
is poured through the sieve into the funnel at the top of the inner
column, the flow being distributed over the whole of the circum-
ference of the inner cylinder by means of small channel ways;
from thence it slowly flows over or drips from each baffle plate in
turn, i. e. down through the whole height of the annular column,
thus exposing a large surface for impregnation with the creosote-
laden smoke with which the whole annular space is filled from
the adjacent slow combustion fireplace. The smoked latex is
collected in the dished bottom of the annular space, and finally
issues from a pipe into a receptacle below, to be put tlu'ougli the
machine again should it requite further treatment." During
working operations it was necessary to cool the smoke before its
arrival at the latex cylinder and even then the hot fumes from the
smouldering latex appeared to coagulate some of the latex along the
baffle plates. This apparatus, though capable of doing good work,
does not appear to have been improved since the Exhibition
and it is doubtful whether many such machines are, at present,
in use.

Macadam's Process

An apparatus brought forward by Mr. C. 0. Macadam of Cul-
loden is designed to impregnate the latex with creosote smoke and to
effect coagulation. According to Zacharias "It consists of a
series of metal planes, slightly inclined and placed zigzag fashion
one below the other. The latex is poured in at the top and has to
flow over all tliese planes, being caught at the bottom in a pail.
The whole is enclosed in a box with an aperture to admit the smoke,
which thus completely fills the interior and thoroughly impregnates
the latex. The latter being poured in again and again, films of
coagulated rubber very soon begin to form on tlie plates ; these
increase in thickness, and eventually form smoke-cured sheets,
which only require drying to be ready for the market."

PARA RUBBER. 171

Wickham's SMOONa Process.

Mr. H. A. Wickham lias patented what may yet be an im-
portant adjunct to estate factories. Tlie macliinc in (juesti(m
provides a rotating or travelling device adapted to carry the nibber
latex mid to expose successive thin layers of it for treatment by
smoke or other agents. A means of directing the smoke or other
agent is also provided.

It is to be observed that by means of this apparatus the cured
product is delivered in the form of a liollow cylindrical ring

In this apparatus dense smoke is produced in the furnace, this
being effected by burning the oily nuts of palms with charcoal.
The liquid latex is poured into the lower portion of a cylinder and
the cylinder is then rotated. As the cylinder rotates, the
bullc 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 india-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 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 considerable thickness is
formed which can be pulled out of the cylinder. The setting of
the rubber films should be observed through the opening in the
side of the cylinder, and the speed of rotation regulated accord-
ingly. By this means the whole of the latex treated is exposed
in successive thin fihus to the action of the smoke and a well-cured
and homogeneous rubber is obtained

The point at which the smoke is first deUverod upon the rubber
is preferably situated sufficiently above the level of the main body
of latex in the cylinder to enable each fresh film to form evenly
before it arrives in front of the smoke jet.

As already pointed out other suitable treating agents may
be used in place of the smoke.

The writer saw one machine in working order in London and
was of the opinion that some modification would be necessary on
the estate. A comi^lete plant was sent to an estate in Malacca
and the results are awaited with interest.

In all these processes the main object is to add a preservative
to the latex or freshly coagulated rubber so that decomposition
will be retarded. The simplest way to effect this is obviously
to add to the latex an alcoholic solution of creosote and mix the
liquids well together. If anything further is required the outer
surface can be smoked by placing the coagulated or pressed rubber
in a building charged with smoke. To eft'ectively treat the latex
with antiseptics or to smoke the rubber in its initial and final
stages should not be very difficult.

172 PARA RBBER.

I)a Costa's Smoking and Coagulating Plant.
A new process for coagulating latex and nieclianically incor-
])orating the particles of rubber with creo»ote has recently been
l)r(>ught forward. In this method the latex, when brought from the
field, is strained to remove mechanical impurities, and is then poured
into the coagulating tanks. Steam is meanwhile being raised to
about 30 to 3.5 lb. per square inch in the boiler, forest woods
alone being used for this purpose.

On the burning wood in the boiler furnace green Palm leaves,
luits, or any green twigs of tropical trees arc thrown, snuiU quan-
tities of acetic acid and creosote being thereby obtained. The
fumes are accumulated in a special receptacle and forced into the
coagulating tanks by a steam injector

The force of the steam violently agitates the latex and during
this operation every particle of it is said to be reached by the
smoke. In a short time the whole mass coagulates and the
floating rubber can then be removed.

The inventor proposes to allow the coagulated rubber to cool off
in the tanks, and afterwards have the masses pressed and blocked;
the blocks to be subsequently reblocked in cube form and after-
wards dried either in a special stove or vacuum dryer.

It is claimed that this smoking and coagulating plant allows
the planter to dispense with chemical re-agents in a liquid form
and ensures that rubber of all kinds shall be sent to the market in
a satisfactory condition. The apparatus has been made by Messrs
David Bridge & Co., England.

Samples of rubber prepared by this method have been reported
upon favourably by a rubber manufacturer.

Coagulation by Chemical Reagents.

Ill coagulation by such means the object is to use reagents
mhich, while elTectively and rapidly precipitating the coagualable
waterial, will not have a detrimental effect on the rubber produced.

Many compounds, such as picric acid, would rapidly induce
C(>;igulatioii, l)ut the effect on the resulting rubber wouhl bo bad.
\\'el)cr and Parkin jiave .shown that many acids may bo 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 producers in the Tropics and manufacturers in
Europe.

Acetic acid. — This is cheap, always procurable, is not dangerou?
to handle, and is as effective as formic acid. It is not as powerful
as tatuiic acid, tliough it is effective in bringing about the coagulation
of the latex while cold. The commercial article varies in strength

PARA RUBBER. 173

and the quality sljould bo noted by the purcliaser. The rubber
produced by means of this coaguhmt, is, according to Henri, of
inferior quality.

Formic acid. — Tliis, thougli siniiUir to acetic acid in its effect, is
more expensive, weigiit for weight. The advantages of using this
reagent are (1), that less is required than acetic acid, and (2) it has
antiseptic properties. Wiietlier acetic or formic acid is used, it
should be applied in definite proportions, and no more need be used
than is required to just precipitate the albumen in the latex. The
same may be said of hydrofluoric acid.

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
occm- if the rubber is thorouglily dry.

Mercuric chloride. — Corrosive subUmate effects coagulation
while the latex is cold, and also acts as an antiseptic It is
very poisonous, and if used a small quantity of mercury is un-
avoidably left in the rubber.

Mixtures. — The following mixture produced a sample of
rubber of excellent quality at the Ceylon Rubber Exhibition in
September last: —

1. 1 dram of Cream of Tartar, dissolved in 1 oz. cold water,

added to a pan full of latex of about 48 oz.

2. 1| dram Cream of Tartar, dissolved in 4 oz. of fresh

rubber when added to a pan full of latex of about 48 oz.

Mr. J. A. Bird is said to have originated the idea.

Mr. H. Hesketh Bell, in giving an account of his observations
in Uganda stated that carbonate of potash is usually added to
the filtered latex, but the objects in view are not clearly defined.

Amount of Acltic Acid to be used.

The quantity of acid required is believed to largely depend upon
the proportion and condition of tlie albumen in the latex. According
to Weber the latex of Para rubber in its native habitat contains
only about 1"5 per cent, of albumen, and one-third of an ounce of
anliydrous formic or half an ounce of glacial acetic acid per gallon of
the latex is quite sufficient to produce a rapid and complete coagula-
tion. The behaviour of the latex from Para rubber trees with acids is
due to the fact that the milk is,when fresh, usually slightly alkahne or
neutral, and the protein substances arc insoluble in a feebly acid solu-
tion but soluble in alkaline or strongly acid solutions. It has been

174 PARA RUBBER.

asserted that the protein matter is insoluble in a neutral solution, but
on several occasions the fresh latex from the Hcnaratgoda trees
remained liquid, though the reaction witli 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
the precipitation of the proteins. It is a mistake to add excess
of acetic acid, as the proteins or their derivatives would be partly
re-dissolved and, therefore, still remain in solution.

The amount of pure acetic acid necessary for complete coagulation
depends upon the quantity of proteins to be precipitated ; the
latex in Ceylon, according to the analyses already quoted, contains
from 2 3 to 2*8 per cent, of these substances. If ordinary latex is
allowed to stand for some time, the protein matter decomposes and
acidity sufficient to lead to coagulation is developed. Diluting the
latex will not reduce the total quantity of acid required. Every
100 volumes of pure Ceylon latex require approximately one volume
of pure acetic acid. Many planters add one or two di'ops 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
neutral after stirring — i.e., will neither turn litmus paper red nor
blue, or vm til it is feebly acid — very little harm will be done. The
addition of excess of acid maj' bring about a re-solution of the
jjroteins and coagulation be thereby delayed. It is very rare
that the latex on a large scale is heated before treatment with
acetic acid.

Time Required for Coagulation.
The completeness of the precipitation is judged by the clearness
or turbidity of tlie liquid in which the rubber floats. When the
separation of caoutchouc is complete, the mother liquor is quite
clear ; where special machhies are used tlic 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 completcc oagulation.

Method of Determining the Amount 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 coohes 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 quanti-
ties of rubber, but when one considers the variation in composition

PARA RUBBER. 175

of ordinary samples of undiluted latex from different trees, or when
obtained at different times of tlie 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 cannot be recommended excej)t 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
rather than add too much.

The amount of acid required can be determined witli ease. Let
the coolies pour the diluted latex from the different trees into a set-
tling tank or ordinary receptacle and fill up to a known level, so tliat
the exact volume Avill be known. After tlioroughly stirring the mix-
ture take a small sample of known volume and add dilute acetic
acid of constant strength, drop by drop, from a burrette 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 tiie 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 involves the accumulation of the latex in recep-
tacles of known capacity and provided with mechanical 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.

Advantages and Disadvantages of adding Chemicals to the

Latex.

It has been frequently contended that the home manufacturers
object to the use of chemicals in the coagulation of the latex, parti-
cularly 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 manu-
facturing 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.

On the other hand, it can be shown that the addition of reagents
such as formalin, corrosive sublimate, creosote, or acids such as for-
mic and even hydrofluoric, have a preservative effect on tlie rubber
when used in infinitely small quantities. When one considers the
chemicals which are incorporated in rubber of good repute prepared

176 PAEA RUBBER.

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, accompany-
ing the use of the required quantity of acetic acid, viz., the rapidity
and completeness of the coagulation effected.

In one experiment about 1| gallon of ordinary latex was poured
into a large glass beaker and allowed to coagulate naturally. At the
end of two daj^s 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 sur-
face and were removed; after six days the mother liquor still remained
turbid, and a further quantity of rubber was prepared from it by
treatment with a small quantity of acetic acid and heating. The
completeness of coagulation, when the latex is allowed to set un-
treated 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 perliaps waste ; certainly it would
involve considerable irregularity to the j)roducer. The use of acetic
acid, on the other hand, effects coagulation in a few hours, and the
mother liquor becomes perfectly clear in less than a day ; the pre-
cipitation is complete, and there is therefore no waste of rubber.

If the ]>lanter is compelled to stop using acetic acid for assist-
in<y 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 reagents 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 longer period
of time would be required for the necessary acidity to develop in
presence of either of these reagents.

In the absence of definite information from home manufacturers,
the use of minimum quantities of acetic acid, determined by the
simple method previously described, is likely to be continued by the
producer in the Tropics ; it is a constant factor in the preparation
of fine Para rubber in Brazil. It will be necessary to prove that the
effect of the use of acetic acid is really ])ad before the producer will
risk the possible loss in yield suggested liy the frecjuent turbidity
of the mother liquor, and the uncertainty or delay incurred in the
production of rubber from latex by the natural process.

For the present the application of tlie correct quantity of plant
juices or acid, followed by thorough washing and rolling, may be

PARA RUBBER. 177

adopted, but care must be exercised not to add excess, and every
effort be made to subsequently expel the reagent by suitable
mechanical processes.

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 reagents which are now so largely
used on Eastern estates produce an inferior rubber others should
be taken up. Hem-i claims to have proved that " the structure of
the coagulum varies with the nature, and concentration of the
•substances emploj'ed 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 recticular
structure. When the structure of the reticular curd obtained by
difi'erent 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 va.ry much with the different
coagulants employed."

The curds which Hem-i 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): —

Mode of Coagulation.

Heat 80 deg. C .
Heat 25 deg. C.
Weak acetic acid
Strong acetic acid
Tri-cliloracetic acid
Acid + electrolyte 1
Acid + electrolyte 2
Acid + electrolyte 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 %vith 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 Dr. Spence,* who now states
that the elastic properties of rubber niivy vary witli the coagulant
employed. This is a point which should be well studied by all
planters who are anxious to improve the physical properties of

* Fontumia elaatica, by Dr. Spence, India-Rubber Journal, August, 1907.

(23)

)ture Stress per
millimetre.

Elongations.

150 g.

8-5

190

7-2

175

7-5

210

325

6-8

310

[ 6-8

380

6-8

660

6-5

178 fPARA RUBBER.

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. Dr. Spence is
of the opinion, from his analyses of Funtiimia clastica 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?

Coagulant and Steength of Vulcanized Rubber.

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 disapipear,
even if it has not already been obliterated during the process of
mastication. They sliould 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 most 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.
Tlie 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 improved
the tensile strength without materially affecting the specific gravity.

Components of Coagulated Rubber.

Whenever the rubber is prepared by ordinary coagulation, either
by the smoking method or the use of familiar chemical reagents,
hot or cold, it is obvious that the rubber must contain the precipita-
ted proteins together with the suspended globules of caoutchouc,
resin , &c. Analyses of well-dried Para rubber show only a small per-
centage of substances other than caoutchouc — practically from 4 to
5 per cent. — and it may at first sight appear unnecessary to draw
attention to the desirabihty of extracting them. If one compares
the analyses of latex and rubber from Hevea hnmUensis , it is
surprising to find that when chemical reagents have been used
the percentage of protein matter in the rubber shows tliat the whole
of that in the latex was not precipitated, and Bamber and Parkin
proved that the clear Uquid remaining after coagulation with acetic

PARA RUBBER. 179

acid often gave re-actions with the tests for proteins. The amount
of protein in the clear Hqiior 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 witli other substances leads in many cases to
putrefaction.

Putrefaction and Tacky ok Heated Rubber,

The protein matter is responsible for much of the "tackiness "
or " heating," which is seen in many rubber samples. The rubber
first becomes sticky, and sooner or later apj)ears to melt as if exposed
to excessive heat. It often emits a strong odour when in this stage.
This is due to the inclusion of the proteins and perhaps the sugary
and gummy constituents in the rubber and the subsequent develop-
ment of micro-organisms on these substances. If tlie rubber is
free from tliese materials it will not undergo such a change, and tlie
removal of the latter from rubber takes us into several important
methods of purification. The chemical change which takes place in
tacky rubber is indicated in the analyses, made by Mr. M. Kelway
Barabor, of sound rubber and material in various degrees of tacki-
ness. They are here quoted in full : —

Analyses of Sound and Tacky Para Rtibher, *
Sound Rubber. Tacky No. 1. Tacky No. 2. Very Tacky
Moisture .. 0-30% .. 0-36% .. 0-06% .. 6-44%
Ash .. 0-38 .. 0-28 .. 0-54 ' .. 0-72;

Resin .. 2-36 .. 2-32 • .. 2-66 ' ... 3-70,

Protein ..3-50 .. 3-85 .. 3'. 50 .- 4-90'

Rubber ... 93-46 .. 93-19 « 93-24 ^ 90-24

100-00 100-00 100-00 • 100-00

These analyses show a relationship between the degree of tack-
iness and the percentage of proteins and resins; the latter may be
due to oxidation. Too rapid diying is said to induce softening and
tackiness in raw rubber.

Use of Antiseptics.

If the local conditions are such that the rubber cannot be prepar-
ed 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 reagent which has antiseptic properties,
such as creosote or corrosive sublimate, and quickly drying the rub-
ber after efl'ectively washing and pressing the freshly-coagulated
material.

Moisture, Washing and Putrefaction.

In some cases it is doubtful whether it is even necessary to add
antiseptic reagents if the rubber is thoroughly dried, as decom-

* Committee of Agricultural Experiments, Peradeniya, S«pt., 1905.

180 PARA RUBBER.

position is more or less dependent upon a supply of water being
present. A communication from Messrs, Lewis and Peat on this
subject is given in the chapter dealing with plantation and fine
Para rubber.

No matter whether the latex lias 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.

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 condition 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 quicker and more effectively the rubber
is dried, the less hkelihood there is 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 reagent 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
and washing. We have seen that Henri 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 (FormaHn), 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 ^ oz. to 1 oz. of formal-
dehyde (formahn 40 per cent, solution) is added, the latex well stirred
and allowed to stand for one hour. Then to each gallon of latex a
solution of 1 lb. of sodium sulphate (commercial) in one pint of boil-
ing 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 reaction.

"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 tlie 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)

Fig. I

Fig. 2.

THE MICHIE-GOLLEDGE COAGULATOR-

PARA RUBBER. 181

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 albu-
minous, though v^ery dilute, mother liquor. If, therefore, the i-ubber
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 an ordinary rubber washing
machine." The formalin acts more as an antiseptic to prevent
the decomposition of the protein than anything else, and does
not affect the specific gravity of the naother liquor.

Johnson made several attempts, when Director in the Gold Coast,
to separate rubber from Para latex in the manner above suggested,
but failed in each instance, although the latex stood, in one or two
instances, 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 reagents e.g. ammonia,
serenguiana, &c., will keep the latex in a liquid state for a very long
time, and might be used with advantage in such experiments

Rapid Coagulation and Removal of Proteins by
Mechanical Means.

It has been stated that mechanical appliances have been invent-
ed which can effectively ehminate the protein normally forming part
of the latex.

Biffeji's Centrifugal Machine.

Eiffen* recognized that in latex the india-rubber 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 Para latex is said to be
effectively separated in a few minutes and to consist of the pure
article, free from mixtures of proteins, resins, &c. Weber strongly
recommended such a process of treating the latex for eliminating
proteid 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

* Biffen; Annals of Botany, June, 1898. Journal of the Society of
Arts, 1898.

182 PARA RUBBER.

smell and danger of decomposition. It is, however, questionable
whether pure caoutchouc free from resinous and otlier impurities
is desired by the manufacturers.

Experiments in Ceylon.

Furthermore, several small experiments carried out in Ceylon
have proved that the caoutchouc in ordinary Para latex is not rapidly
separated by the centrifugal machine, even when the speed is as high
as 11,000 revolutions per minute. In these experiments various
heavy chemicals have been added to the latex after the formalin ;
the chemicals used do not show an acid reaction, and considerably
increase the density of the alkaline mother liquor. The whole
of this mixture has been placed in the "Aktiebolaget Separator,"
and then been subjected to centrifugal force for over an hour, and
yet the caoutchouc globules have not been effectively separated
from the other constituents.

Though these experiments cannot at present be considered a suc-
cess, the principle of increasing the density of the mother liquor 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.

Rapid Coagulation by Mechanical and other JNIeans.

The Micliie-Golledge Machine.

Construction. — On the accompanying plate a sketch of parts of
this machine is shown. The Michie-Golledge Rubber Coagulating
Machine consists of a revolving cylinder A, with angular ribs B on its
inside, and curved blades C which are fixtures, as shown in the
accompanying sketch. The latex is poured into the cylinder A,
which is then set in motion, the machine revolving in the direction
indicated by the arrow. The revolving cylinder and its ribs B force
the latex forward on to the blades C, which carry it into the centre
of the cylinder, creating a kind of vortex or whirlpool, and depositing
the rubber in the central space in the form of a sponge-like mass.
When the mass of rubber reaches the right consistency, it is removed
1)V hand, separated into lumps of the required size, and rolled out
wiiile it is still soft into slieets in a small rolling macliine.

Method of IJsiwj. — 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 1 dram of acetic
to 1 gallon of the diluted latex, is placed in the churn-like cylinder.
The cyhnder is then rotated horizontally at the rate of about 180
revolutions per minute for about 11 minute, after which the speed
is reduced to about 100 revolutions per minute for the next 3|
minutes. The coagulated latex accumulates in the centre, and the
waterj" 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

Photo bv C. H. Kar.
THE MICHIEGOLLEDGE COAGULATOR

THK SPONC.Y MASS OK FHKSHI.V t OA(i lI.ATi:] I lillWii;!! IS SHOWN AT THK TO)'.

t»AUA RUBBER. 183

coagulated latex is removed. Tlie freshly-coagulated mass is, as
8]io\\i\ elsewhere, in the fresh state very spongy, and is torn into
irregular pieces which are pressed between the rollers of a mangle.
A figure of the mangle used and the cakes obtained is shown on the
accompanying Plate ; 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
portion of which may be partially removed by repeatedly washing
the rubber during the rolling process. Two analyses of tills
rubber are given elsewhere.

Mathieu's Apparatus.
An'apparatus for coagulating rubber in large quantities by means
of heat alone has been considered by Mathieu, which follows in prin-
ciple the manipulation of the latex as practised by the Brazilian
sermguero. As far as I can understand it, the apparatus is devised
to subject thin films of the latex to the action of a surface heated to
a constant degree, and can be worked in situ or be put on wheels
and transported to any part of the estate where collecting operations
are being carried out. Dickson's drying and coagulating machine
is described in Chapter XIV. of this book.

A Xew Coagulator.
A new coagulator invented by Mr. Harvey, of Pataling
estate, and known as the Kuala Lumpur Coagulator was exhibited
at a recent exhibition at Kuala Kangsar. Compared with other
processes the new coagulator is said to require only a fraction of
the amount of coagulant ordinarily used, and is 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
is taken.

The " K. L." Coagulatok.

Mr. Harvey, in describing his machine, wi'ites to the Federat-
ed Engineering Company Limited as follows : — •

1. This machine has been designed to fill a long-felt want
in the up-to-date rubber factory. It 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 iiinued-
iately it arrives from the field, and a perfect coagulation can be
etfected iji five minutes. Thorough bulking of latex is assured.

3. By the use of this machine all decomposition of tlie
proteids contained in the latex is rendered impossible, and when
tlie coagulated rubber is waslied tlirough a machine there is an
entire absence of that unpleasant odour so associated with new
rubber which has been coagulated in pans

184 I'AIIA RUBBPJR.

4. The oui-luin of dry rubber will bo fouiul to bo mora
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 of any other coagulating
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,

6 of water to 1 of Glacial Acetic, and

1| fluid ozs, of 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
throughout 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.

Supposing there to be about 35 gallons of latex in the
coagulator, it will be noticed that coagulation starts in about five
minutes, and when once this is the case, it will be found 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.

An illustration of this apparatus is shown elsewhere.

Coagulation in the Field or Factory.

On most estates the latex is collected in the field and
despatched 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
transmitted ; in order to effect economy several planters have
suggested that coagulation should bo done in the field and only
the freshly-coagulated rubber need then be carried to the central
factory. Mr. GoUedge, 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 bo carried to the factory for final
manipulation.

THE "K L" COAGULATOR

CHAPTER XIV.
DRYING OF RUBBER.

General Mothods — Illustration showing the method of drying biscuit
rabbor — Water, putrefaetion and surface deposits — Ciieraicals and
artificial lioat for drj'ing — ^ Water in wild and plantation rubber — ■
Removal of moisture from plantation rubber — Immediate removal
of moisture from rubber by manufacturers — Effect of moisture
on the strength of rubber — Reduction of moisture and increased
strength — Exiieriments by Schidrowitz and Kaye — The tensile
strength, elongation and resihency of chy and moist P'untumia
rubber saniples — Water in and price of i-ubbor — Creosote and
wet plantation rubber bj' liauiber and \Villis — iVlanufacturers
against wet plantation rubber— Methods of drying in the East —
Exposure to the air — Cold air curreiits — Hot air rooms — Vacuum
ch'3 iiig — Method of using Passburg's drier — Vacuum dryers in tlie
F. M. S. — Advantages of vacuum drying — Rapid and slow dry-
ing— Manufactur(>rs oft(>n prefer slowly ch:ie;l rubber— Bubbles in
rapidly dried rubber — ^Rapid drying without va /uum driers —
Dickson's machuie for coagulating and drying rubber — Use of
Calcium chloride — Hot air chambers and the use of hygroscopic
chemicals.

ON most estates the freshly-coagulated rubber is rolled to drive
out as much water as possible, and then either hung up on cords
or placed on shelves made of coarse wire netting, coir matting, or wood,
and allowed to diy. The rubber cannot be dried in the stm, though
a current of warm dry air may be used without any bad effect. The
ordinary cacao and tea-drying factories might easily be used for this
purpose. The preparation of the rubber in sheets as thin as possible
is desirable in order to obtain a dry rubber in the shortest time,
though a minimum thickness of one-eighth of an inch is preferred by
buyers in Europe. Though the drying process may be hastened
by various methods, it is weD-known that rubber of good quality
can be produced without resorting to any devices for hastening
the di-ying or curing of the product. The illustration given else-
where shows a simple method of drying biscuit rubber as
adopted on many rubber estates. Crepe, flake, worm and lace
rubber are capable of being diied more rapidly than thick biscuits
or sheets.

The presence of water in the rubber is often a serious
drawback ,and the fact that the rubber, if dry, will not undergo putre-
factive changes is of sufficient importance to warrant attention to
this part of the subject. It should be remembered that when the bis-
cuits or sheets are hung up to dry the evaporation of the water is
followed by a deposition of the suspended or dissolved impurities on
the surface of the rubber they should be removed. Immediate
drying is essential in order to prevent deterioration consequent on
oxidation; too rapid drying is said to induce a softening of the
rubber.

(24)

186 PARA RUBBER.

Chemicals and Artlficial Heat tor Drying.

Parkin* stated that to dry rubber by heat did not seem
advisable, and suggested that perhaps quicklime or calcium chloride
might be used in the drying chamber.

Burgessf states that the raw rubber, before it is vulcanized, is
very sensitive to heat, and a temperature of 150° P. may render
]*ara rubber sticky on the surface, and a higher temj)erature utterly
destroy the "nerve" of it; he declares that it is, therefore, danger-
ous to use artificial heat in hastening the drying of rublDer. He
also states that if artificial heat were absolutely necessary a very
carefully regulated temperature, never exceeding 120° F., would
probably not cause any great damage.

Weber; asserted tliat certain brands of india-rubber cannot be
hung up to dry in the form of sheets after the washing process, as
they become so soft as to fall to pieces. The temperature at which
india-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.

Water in Wild and Plantation Rubber.

The majority of rubber exported from the various African and
American ports contains a large proportion of impurities; even
fine liard Para and Lagos lumj) frequently possess over ten per
cent, of water alone on their arrival in Euro])e. Many of the
wild rubbeis exhibited in the ordinary London sale room can, by
means of hand pressure alone, be made to eject water in (juantitios
indicative of there being about twenty per cent, of moisture alone
in the crude samples. This variation in the moisture contents
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 almost dry rubber received from
well-managed Eastern plantations; this freedom from moisture and
consequent constancy in composition is largely responsible for the
agreement in average prices realized for consignments of Para rubber
from iinnnnerablc estates in Ceylon and Malaya. 'I'lie production
of rubber free from moisture may involve tlie erection of certain
machinery and necessitates a certain amount of delay in deliveiy.
Removal of Moisture erom Plantation Rubber.

The desirability of removing the nu)isturc from plantation
ruljber has been discussed in many quarters and the subject raises
immcrous points of interest. In the first case it should be remem-
bered that the ditterence between wild and plantation rubbers is
not one of moistiue alone; a series of factors such as the jjroportion
of putrescible matter and its state of preservation, the age of the

* Parkin, Z. c. p. 15L

i Burge9e,Lectureatthc Agri-Horticultural yhow, Kuala Lumpur, 1904,
:;: Chemistry of India-Kubber. p. 21.

Photo by Ivor Etherington.

DRYING BISCUIT RUBBER.

PARA RUBBER. 187

trees whence the rubber was obtained, etc., all play a part in
giving to wild rubber itsgeueral characteristics. So far the results
of scientitii' experiiuents with wet and dry rubber have not been
published, though much has been written by interested parties in
the East on this subject.

An advisor to Messrs. Lewis and Peat pointed out in 1906 that
"Ceylon and Straits biscuits and sheets are at present made too
pure — too much moisture being taken out of the rubber — with the
lesult that the elasticity and strength are reduced; such rubber, it is
stated, will not keep, but inevitably becomes soft and treacly if stored
for any time or subjected to pressure and a raised temperature ."

The same advisor goes on to suggest that it is the extra moisture
left in the fine Para '■ smoke-cured" that renders it fit and strong
enough for all purposes, and accounts for it not deteriorating after
beuig kept for any lengtli of time. To this the Editor of the
'India-Rubber Journal' (April, 9th, 1906). replied 'if this if 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 diy sheet rather than in the state in
which it arrives I The answer is, simply because that thoroughly
washed and dried rubber under suitable conditions will not
deteriorate until after a very long lapse of time. The manufact-
urers'dried rubber contains no moisture at all, and in the old da3''s
it used to be stocked for two or three years before being used
for special purposes. It therefore cannot be on account of the
lack of moisture that the rubber deteriorates." It is finally
suggested that the plantation rubber should be smoked and made
up into large balls, bottles, or cakes, as in Para. The same
firm in their circular dated December, 1905, stated that "///e venj
c/reatest core should be taken that all rubber is absolutely dry before
being packed." Obviously, in the opinion of Messrs. Lewis and
Peat, the <iuestion of how to prepare the rubber for the market
was, at the time, a vexed one and deserving of nmcli experiment.

Mr. (*. Devitt, when lecturing at the Ceylon Rubber Exhib-
ition in September, 1906, stated that 'one of tlie 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 case-full. 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."

It will be noticed that the above remark was made with
special reference co the surface moisture and not, apparently, to
that which might be included between the layers of rubber.

Efffct of Moisture ox Strength of Rubber.
Bamber, after giving the analyses of various rubbers, states,
in the Ofticial Handbook to the Cevlon Rubber Exhibition, that

188 PARA RUBBER

" A careful stud}^ of the figures sliows how diflficult it is to form
deductions as to wliat gives actual strength in the rubber, for the
strongest rubbers have not necessarily the most caoutchouc, though
the difference of 1 per cent., in such high numbers as 93 to 95 per
cent, would have very slight effect ".

He further says, on the subject of moisture and strength : —
" 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 which
Bamber subsequently made in connection with the preparation
of wet, creosote, rubber detailed elsewhere.

Reduction of Moisture and Increased Strength.

Messrs. Schidrowitz and Kaye, in their paper* on "The In-
fluence of the Method of Coagulation on the Physical and Chemical
properties of Funtnmia elastica", point out that, as might have
lieen 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 case in an appreciable
increase both in tensile strength and distensibility. This is of
particular interest in view of the fact that fine hard Para contains
considerable more moisture than any of these moist samples. It
is probable that in the moist Funtumia samples the moisture is
present in a quasi-molecular state whereas in fine hard Para the
remanent moisture is merely mechanically admixed. It is perfectly
plam that every variety of rubber must be separately considered
in regard both to coagulation and methods of drying, &c. It will
be noticed that 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 murit depend,
according to Schidrowitz and Kaye, on the class of rubber being
treated and the manner of coagulation. It does not necessarily
follow that rubber which is packed somewhat moist will on arrival
and after washing and drying by the manufacturer, give worse
results than a rubber which is shij)ped very dry. It depends on
whether the conditions of preparation of the crude rubber are sucji
that an appreciable quantity of moisture is dangerous as regards
mould formation or not. From the results obtained by tliemselvea,
and other experiments with plantation rubbers, they were led to
conclude that a systematic examination of the latices and methods
of coagulation of Kevea rubbers would result in a very great
improvement in much of the plantation rubber put on the market ;
the following is an extract from their table of analyses : —

* India-Rubber Journal,' Sept. 23rd, 1907.

Plioto by C. H. Kerr.
MACHINERY FOR EXPELLING WATER.
SPONGY RCBBEH PItEPAHED BY THE MILHIE-GOLLEDGE PROCESS.

TARA RUBBER.

189

190 PARA RUBBER.

Water in, and Prick of, Rubber.

It is obvious that when rubber varies in its water content
tlie price paid for the crude material will also vary, and only
where the rubber is free from all impurities and of relatively
constant composition will the price be at all constant. It is
tlie habit of some buyers of crude rubber to test the samples
for their water and grit by hand only, though no one doubts
the impossibility of thus accurately estimating the percentage
of moisture in samples from various sources. The present prices
for fine hard Para and plantation Para are 3s. 2d. and 3s. 6d. per
lb. respectively ; the former contains about 20 per cent, and the
latter less than 0-5 jier cent, of water, so that the price paid
for fine hard Para is, pound per pound of dry rubber, more than
tliat paid for plantation. This increase in price paid for fine Para
is as it should be owing to the superior qualities of fine Para
when compaied with tliat from ordinary plantations ; it does
not mean that plantation rubber is getting a lower price on account
of its not possessing water ; the difference paid is no logical
reason why any person * should have suggested the shipping of
])lantation rubber containing a higher proportion of water.

Creosote and Wet Plantation Rubber.

Messrs. Bamber and Willis f recently carried out experiments
to test the possibility of sending home undried rubber preserved
witli the aid of creosote. Acetic acid and a mixture of creosote
in methylated spirit, were added ; 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,
Tlie block so prepared contained from 8 to 9 per cent, of water,
but the authorities thought that tliis might be reduced to 7 per
cent, if necessary.

Samples prepared in the above manner were valued at 5s. fid.
per lb. Messrs. Bamber and Willis ])ointed out that as ordinary
Ceylon plantation rubber contains less than 1 ])er cent, of
moisture, the price obtained for the experimental samples was
e((uivalent to 6s. a pound for the actual rubber they contained.
The actual sales on the same day were ''Culloden'' 5s. 9j-d. and
on seven other estates 5s. 7fd. Tiie rubber therefore obtained
a price 3d. better than tlie exceptionally good lot sent from
('ulloden; this compared very favourably indeed with any
previously realized, thougii it was not up to that of tine Para
from South America.

* Tropical Agriculturist, Colombo, November, 19 06.
t Circular R, B. G., Peradeniya, January, 1907.

PARA RUBBER. 191

The following analyses by Bamber show the composition of
the wet rubber after drying ten clays, and the average of good
Ceylon biscuits :—

OitKo.soTKD Wkt Ruuhkij. Avkuagk Ckymuv Biscuit-

per cent. per cent.

Moisturo .. 7.06 .. 0.45

.\sh .. ... 0.18 .. O.-St

Resin .. 1.92 .. 2.01

Proteins .. 3.67 .. 2.37

Caoutchouc .. 87.17 .. 94.83

100.00 100.00

Nitrogen 0*58 0.37

Messrs. Banibcr and Willis concluded that the ])lanters 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.

From this experiment they concluded, " that it is evident that
the erection of large factories for the mechanical treatment and
the drying of rubber would be premature."

The experiments are of considerable interest, and though
the hasty deductions arrived at were not warranted from the
results obtained they should be borne in mind. It is perhaps,
needless to point out that rubber manufacturers will not pay
very much for water ; they generally prefer uniform and pure
plantation rubber.

Manufacturers Against Wet Plantation Rubber.
The users of plantation rubber are, in virtue of their long
association with rubbers of many kinds, able to give very sound
judgment on the question of sending plantation rubber home in
the wet or dry state. The " India- ilubber .Journal," in their
issue of September 23rd., 1907, gives tlie following account of the
opinions of manufacturers on this point : —

" In view of the publicity which was some time back given to
the valuation of a small sample of wet creosoted block rubber, the
recommendation which the experimenters gave, and the arrival of
rubber containing moisture and creosote on the London market,
we considered it advisable to approach, direct, the users of
wet and diy rubber. The question put before them was :
''Do you prefer to receive plantation rubber in the pure and dry

192 MRA RUBBER.

btate or with water and creosote 'r' If manufacturers will pay
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 and, as
pointed out by Messrs. Bamber and Willis, the erection
of costly drying apparatus will not bo necessary. It would,
furthermore, give rubber to the manufacturers in a condition
very similar to that in which the bulk of their present
supply arrives, and perhaps result in the physical improvement of
jilantation rubber. The questions of whether the manufacturers
required the rubber in tlie wet and creosoted condition, what
impiovements, if any, were effected in the physical properties of
rubber so shipped, were, however, not known when Messrs. WilHs
and Bamber published their circular in January 1907. The
publication was condemned in this Journal early in the year, and
as the manufacturers have had time to carry out their own experi-
ments, their verdict is worthy of every consideration. The replies
liave been shown to a London representative interested in the
original wet creosoted rubber, and we only regret being unable to
quote the names of the firms who have favoured us with their
decisions. One manufacturer, who has condemned plantation
rubber all along the line as an inferior product, and who has not
yet been convmced of any special purposes for which it is useful,
(though he guarantees its uselessness for certain articles) declares
that he is quite indifferent as to whether the plantation product is
dry, 2)ure, wet or treated with antiseptics, as in every condition it
Jias, so far, been unsatisfactory. We are glad, however to know
that this opmion is not universally held, and that some manufacturers
find purposes for which plantation rubber is specially useful. They
are, with the above exception, all in favour of first-grade plantation
rubber being in the dry and pure state. The following are the
exact replies of several firms in reply to the question given above: —
"Dry state" ; "Pure and dry" ; "Pure and dry state" ; "Pure and
dry state most decidedly" . This unanimity among manufacturers
usmg the rubber for entirely different purposes came as a surprise
to us. Not ashigie firm repUed to the effect that they preferred the
rubber in the "wet and creosoted" condition; they plumped for
the "dry and pure state". We are naturally satisfied to have such
a general confirmation of our views, and if only the planters in the
East will realize how important it is that their rubber shall always
be at the top for price, purity, and constancy, even if the main-
tenance of that reputation necessitated what, for the present, appears
ahnost unnecessary expenditure, we tliink they will beweU 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; we trust that no recommendations will be
issued mitil the opinions of manufacturers ha\e been secured on the
samples submitted."

PARA RUBBER. 193

In the same issue the " India- Rubber Journal" states that
many of the manufacturing firms liave writte.i suggesting that
the purity and quality of plantatioji rubber should be maijitained ;
the general tendency of the requirements of the manufacturers,
appears to be that they are not certain of the purity of the rubber
wJiich will come, or is now coming, from plantations hi the East;
they are, more or less, unanimous in their requests for the delivery
of rubber in as pure a condition as possible.

Methods of Drying in the East.

Putting all theoretical considerations aside and assuming that
the planter desires to turn out rubber in the purest possible form
and that the greater part of the water must be removed, there are
four methods which can be employed.

Exposure to Air.

The first method consists in exposing the latex on banana or
other large leaves to the sun and subsequently peeling off the
thin layers of dry rubber and rolhng them into a ball or block. This
is a practice which 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,
nevertheless, carried out on some native 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 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 must be
allowed for the slow drying process. This is obviously a very poor
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, however, in their 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
on the surface or mouldy.

Hot Air RooiMs.

The third method is that of using hot air chambers provided
with shelves along the sides and in the middle of the room. The
temperature is maintained at about UtJ to 100^ F., by means of
hot air drawn tlirough the building by means of a fan , or by
means of steam pipes running round tlie building. This is a
method which, to dry rubber of } to I inch in thickness, may
require one to two months and on that account is obviously one
which cannot ahsays be rccommcmleil for estates dealing with

(•2-, )

194 PARA RUBBER.

large quantities of rubber. If this nietliod is adopted the tem-
perature of t]ie room should never be allowed to rise above 120^F.

Vacuum Drying.

The fourth method is that of drying in vacuum chambers.

In the " India-Rubber World " (November 1 , 1905) a suggestion
is made that tlie principle of dryuig rubber in vacuo might be tried.
It is maintained that drjdng in vacuo is accomplished rapidly,
only low temperatures are necessary, and a great saving in fuel,
space, and labour is effected. The vacuum drying chambers may
be obtained in rectangular and in cylindrical styles and fitted with
plate shelves or shelf coils inside. According to Burgess, a vacuum
chamber consists of a large iron box, of from 100 to 200 cubic feet
capacity, fitted inside with shallow trays with perforated bot-
toms, and lieated with steam pipes, the interior being connected
by an iron pipe with an exhaust pump. The temperature of the
chamber is raised to 120 to 130° F., and after the air has been
drawn through the chamber for a few hours the rubber is usually
sufficiently dry for most purposes. Most manufacturers, however,
have not adopted drying in vacuo, as they believe the rubber is
softened by the heating and the nerve and quality of the rubber
injured, but prefer to dry the rubber gradually in dark warm
rooms,

This method, which is now being rapidly taken up on some
f)f tlio n\ost prominent rubber estates in the East, applies equally
to all kinds of rubber and enables one to manufacture rubber
nearly dry in a sound state, ready for making up into blocks.
In a vacuum chamber one can dry ordinary biscuit, sheet, or cr6pe
lubber. The rubber is allowed to remain in the vacuum chamber
until only about 1 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 moihiture 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 skill, be easily
regulated and pr(»viduig the whole of tJie moisture is not extracted,
good lesults can be anticipated. The {quantity of lubber which can
be dried in a given time by means of a vacuum chamber depends
upon the capacity, but those with which I have concerned myself
are cajiable of dealuig with 330 lb. of rubber at a time, and in
ordinary rubber- factories can deal, in practice, with large quantities
of wet rubber in 24 liours.

Method of VVorkinu Passblru's DRfERS.
The time that the rubber remains in the chamber is usually
from 1{: to r,' hours. The steam supply is shut olT 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 28i huhcs the temperature of the rubber remains

PARA RUBBER. 195

at about 90° r. until the greater part of the moisture has been
removed. It tlieu slightly rises and is taken out when the chamber
reaches about 120° F.

In the Federated Malay States they are, at the present time,
using a very low steam pressure in the shelves — from 1 to 4 lb. only
— and on some estates they leave the rubber in for 1 J to 2 hours.
When they desire more output from a chamber they will probably
increase the steam pressure and shorten the dryuig time. At the
end of the drying process the rubber is liot and relatively soft, and
is .specially suitable for cutting into strips and conversion into block.
You cannot make satisfactory dry blocks without using the va.'uum
chamber, as it not only gives a dry, but a soft product, easily
manipulated. The warm rubber on cooling sets into a hard block
and does not retain the pliable character of the warm material

Vacuum drying is generally resorted to, when it is advisable to
remove the moisture without subjecting the product to a higii
temperature.

It has been argued that when 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 b:^ dried in the
shortest time, and material turned out approximately pure and
uniform. On some estates they have been desci-ibed as " useless,"
and on others as " indispensable ;" the success with which such a
complicated piece of apparatus is used dep3nds, very often, o:i
the engineering skill of the planter in charge.

Rapid and Slow Drying.

It has been previously explained that in view of the fact
that many of the larger plantations are harvesting very large
quantities of rubber which they desire to dispose of
as quickly as possible, methods of drying, other than the
use of ordinaiy heated curhig houses, will become more common.
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 wliich is
anticipated on many })roperties. 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 wlu) 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 obtaine i when it is
slowly dried.

196 PARA RUBBER.

When rubber is rapidly dried there is a tondeiioy to Iho for-
mation of an impervious skin on the surface owing to the surperficial
layers being dried before the internal portion ; when one is dealing
with very thin sheets or crepe this drawback against rapid drying
is not very formidable.

Bubbles and Vacuum Drying.

Attention has been called to the number of air and steam
bubbles 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 safely conclude that
the method of drying is therefore 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.

Rapid Drying Without Vacuum Driers.

Mr. GoUedge, Gikiyanakanda, Ceylon is, by means of his
system, able to prepare dry crepe rubber, without the use of
vacuum driers, in 12 hours. The freshly coagulated rubber is cut
into worms and the latter dried on trays in a wooden chamber
maintained at 85° F. After 12 hours the worms are dry and on
being passed between an ordinary pair of dry horizontally-fluted,
iron rollers, are united into a continuous even strip of crepe rubber.
Somewhat similarly rapid conversion into dry rubber was done in
Matale with lace rubber.

Dickson's Machine for Coagulating and Drying Rubber.
Mr. Dickson has kindly supplied me with the following
description of his machine : —

•'This machine consists of a small furnace, on the top of
■which is a smoke box containing a revolving drum. Between
the furnace and the smoke box is a series of baffle plates to
divert the fumes and ensure that no flames and sparks pass into
the smoke box. At one side is a shallow pan for receiving the
latex. In tliis pan is a small roller partly immersed in the latex, with
its surface in contact with the surface of the large drum. A fire
s placed in the furnace, and the fumes are allowed to pass between the

RUi3f3f R SAGULATIhG & DRYING MACHIflE-

DICKSON'S COAGULATING AND DRYING MACHINE.

PARA RUBBER. 197

baflle plates and round the large drum to the chimney. When the
desired temperature has been reached the pan is filled with latex
from the feeder, and the small roller is turned by hand or power.

" The surface of the small roller being in contact wifch the sur-
face of the large drum turns it, and at the same time spreads a thin
film of latex on its surface. The action of tlie heat and fumes on
the thin film of latex coagulates and dries it. Continuing the process
the latex is spread film by film, coagulated, and dried until a thick
deposit of rubber surrounds the large drum. The damper on the
centre bafile plate is then shut and the door in tlie smoke box opened.
The rubber on the drum is slit across with a knife and unrolled in a
large sheet, which can be cut to any size for packing.

"The antiseptic qualities of the fumes tend to preserve the
rubber, and the sheets are treated through and through."

In communication with Mr. Dickson I learned that in this
machine tliere are several doors, which can be opened to let cool air
in or regulate tlie temperature — a most important and essential
feature when drying rul)ber with hot air or fumes. The illustration
given elsewhere, sliows the general plan of tlie apparatus.

Another apparatus has been devised in Ceylon to dry the
rubber quickly and to coat the freshly coagulated and rolled
product with creosote, but has not yet been made public.

Use of Calcium Chloride.

Mr. Burgess in his lecture already referred to, stated that it was
possible to dry rubber quite well and satisfactorily without any arti-
ficial heat, by the use of some agent that will dry the air. For this
purpose he recommended 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. The great
merit of this substance lies in the fact that it can be recovered from
the wet state by simply heating and thereby driving off the
moisture. A simple form of rubber-drying shed adopted for use
with calcium chloride could easily be made with shelves to hold
iron pans, in which the calcium chloride could be placed and freely
exposed to the air in the chamber. As the calcium chloride
absorbs the moisture and becomes sloppy, the pans should be
removed and the water driven off over a brisk fire, stirring the mass
meanwhile. When quite dry and porous again the pans should be
returned to the rubber-drying chamber to do their work again. In
this way there would be little or no loss of substance, and the air
inside the chamber being constantly dry, mould would be absolutely
prevented, and the rubber would dry in half the time. The pans,
if used inside the rubber shed, should be placed above the rubber.

198 PARA RUBBER.

'* A still more efficient system would be to devise a circulation of
dry air in tlie chamber, and if this system were adopted it would be
best to dry the air before blowing it with fans into the chamber.
This could be easily done by causing it to pass over a series of iron
pans of calcium chloride contained in a drying box outside."

A writer in the "India-Rubber Journal" objected to the use
of calcium chloride on the ground of expense and the danger of accid-
ental contamination with the rubber, and expressed his opinion
(hat the circulation of dry air was preferable to the use of this
chemical. Mr. Ridley, in reply to these objections in the " Straits
Bulletin," stated that in a manufactory on a large scale the calcium
chloride would be in pans, well away and above the rubber, and that
there would, therefore, be no risk. If calcium chloride is allowed to
remain in contact with the rubber it destroys it, but if cleared off
immediately it does no harm.

At Peradeniya a series of experiments has been made. A
current of dry hot air is made to pass rapidly through a specially
constructed chamber in which the rubber is arranged on a number
of wooden trays. The air is tirst dried by passing it tlirough a series
of crates or cells containing hygroscopic chemicals. The crates
can be easily removed, dried, and replaced. The dry air is then
drawn over a fire by means of a fan, the latter being tunied by
hand or power. By this means the rubber is dried fairly rapidly ; if
the temperature is maintained at about 90° F. ,the rubber is thorough-
ly dried in a few days if the sheets are not too thick, and softening
does not occur if the rubber is not dried too quickly. It is as well to
mention that the softening of rubber alone, when due to too rapid
drying, is not objected to by manufacturers, as the masticating pro-
cess, through which the dry rubber passes, converts the material into
a substance void of all toughness and elasticity; but any softening
of the rubber before it leaves the factory of the producer might
prove very serious as the sheets or biscuits would be bound to
adhere to one another, and probably become tacky before their
arrival in Europe.

CHAPTER XV.
PHYSICAL AND CHEMICAL PROPERTIES OF RUBBER.

Analyses of Para~rubber from Ceylon. Bukit Rajah, Duckwari, Ara-
polakande, Syston, Lanadron and HaAvthorn estates, Penang,
Gold Coast and the Straits. — Analyses of plantation samples
at Ceylon Rubber Exhibition — Analyses of Ceylon plantation
rubber by Schidrowitz and Kaye — Analyses by Bamber of
Para rubber from trees of different ages — Analyses of Para,
Ceara, Castilloa, Landolphia, Ficus, Urceola and Rhynocodia
rubbers compared — Chemical and physical properties of rubber —
Empirical chemical analyses and their value — Caoutchouc by
difference — Opinions of Dunstan — Relation between tlie physical
properties and chemical comijosition — Resins — Resins in Para
rubber — Resins in rubber from Castilloa, Manihot, Landolphia,
Ficus and Haucornia species — Resins in crude rubbers from
Uganda, Mexico, Cejdon and Mala.\- by Scliidrowitz and Kaye
— Removal of resuis from rubber — Characters of resin — Resin —
Free rul^bers — Albuminoids in rul)ber — Asli constituents in washed
rubber — Potassium in washed rubber — The insoluble constituent
— Oxygen — Physical j3roperties of india-rubber — Effect of alkalies,
acids and halogens — Elasticity, resiliency, coloiu- and odour —
Action of heat on rubber

HAVIXG briefly indicated tlie composition and characters of the
latex as it appears in the factory of the cultivator, the same
features in the finished product can now be considered with the
object of gaining an insight into the changes which have taken
place, and tlie processes adopted in Europe to extract from the
rubber impurities originally present in tlie latex. The ])repared
article may be expected to contain all the insoluble components of
the latex, except those removed by mechanical operations. The
following analyses of plaulation rubber, prepared from Uevea

200 PARA RUBBER.

hrasiliensis in various parts of the world, may be taken as good
examples : —

Para Rubber "Gold Coast
Ceylon from the Penang Para Rubber§ Straits I!
Pura Bukit Rajah Para , a ^ Rubber ; old

Rubber.*

Co.,F.M.S.

t Rubber.

•.f A B

sample.

per cent.

Caoutchouc . . 95 • 50

95-37

95-00

95-53 95-90

93-22

Resins, &c. .. 3-00

3-02

4-03

3-90 3-25

1-76

Albuminous

matter .. 1'25

1-24

—

4-20

Ash of mineral

matters

0-25 0

•37 0-05

0-18 0-22

0-32

Moisture

—

— 0-15

0-39 0.57

0-50

Tlie sample from Ceylon was valued at 5s. l\d. per lb., and the
report stated that the rubber was free from moisture, very strong,
and vulcanized well. The sample from the Bukit Rajah Co. was
considered to be very suitable for vulcanization, and sold at a little
over 7 francs per pound. The Penang sample was prepared in
rectangular cakes, was dark brown in colour, transparent, and
contained no meclianical impurities ; one piece was sticky. The
value was considered to be equal to the current market rate of
good Para.

The samples from the Gold Coast were considered to be of ex-
cellent quality, free from mechanical impurities, and in February,
1904, were valued at 45. Gc?. to 4s. Id. per lb. The old sample of
Straits rubber had been kept in Ceylon for a considerable length
of time.

The high percentage of caoutchouc in Para rubber, grown in
different countries, is so far very satisfactor}'-. Johnson has shown
that whereas the cultivated Para may contain over 95 per cent, of
caoutchouc and less than 4 per cent, of resinous matter, the native
African rubber ( Funtumia elastica) contains less than 90 per cent,
of caoutcliouc and over 8 per cent, of resinous compounds. From
the foregoing analyses and valuations it may safely be asserted
that Jlcvca hra,silicmis bids fair to beat many rubber trees intligenous
to tropical areas. Resins in large quantities, albuminoids, and ash
constitutents are not required, and in many articles of commerce
are injurious.

* Troi)iLal Agriculturist, Vol. XXIV. No. 5, November, 1904.

Y Juurnal d' Agriculture Tropicalo, A[)ril, 1905.

X Agr. Bull, of Straits and F.M.S., April, 1904.

§ Joluxson, Report on Rubber in the Gold Coast, 1903.

11 By M. Kolway Bamber.

PARA RUBBER.

201

Analyses of Plantation Rubber.
The following arc the analyses by Mr. Kelvvay Bamber, as
])ublis]ied in the Official Handbook, of various rubbers at the
Ceylon Exhibition ; the first four rubbers were gold medal

samples : —

Para Rubber.

Moisture.

Kosiu.

Ash.

Proteins.

Caoutcliouc.

Duckwari biscuits

. 0.6S

2.32

0.36

3.00

93.64

Arapolakaudo smoked

biscuits . . ,

. 0.28

1.84

0.20

2.12

95.56

Sj'ston slieet . .

. 0.30

2.74

0.20

2.25

94.51

Lanadron block

. 0.30

2.44

0.20

3.31

93.69

Hawthorn Estate, S.

India

. O.CO

3.02

0.40

2.82

9.3. IG

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

Brazilian Para

. 3.88

2.42

0.30

2.97

90.43

As far as the chemical composition of rubber goes, there
seems uotjiing to aeoouut for the differences in the stren-^Mh of
various i)Iantation and other rubbers. The splendid Duokwari
biscuits and " typical weak biscuits" show practically no diU'er-
ence in chemical composition, the percentage of moisture and
proteins are identical, and the weak rubber contains less ash and
less resin and more caoutchouc than the gold medal sample.

Typical weak sheet contains, according to the analyses by
Bamber, more moisture than any of the other samples.

The best plantation samples at the Ceylon Rubber Exhibition
contaii>ed practically no moisture in the majority of cases, there
being less than 1 per cent, present, while a typical sample of weak
Para sheet contained 1-04 per cent, of moisture.

Ceylon Plantation Rubbers
(1)

Very thin biscuit
1/3 to l/o ram. iu
centre to 1 mm. at
edges; translucent ;
light amber colour;
edges somewhat
darker.

per cent.
Moisture . . 0*73

Resin . . 1-36

Mineral matter . . 074

" Dirt and* organic im-
purities " .. .. 12 52
India-rubber .. ,. 84*15
Xitrogon .. ,. 0*17
Nitrogen as proteids . . 106
Specific gravity at 15^ C. 0-9160 .,

(Hevea brasiliensis).

(2) (3

Thin biscuit, from
(centre) to 1 mm.
(edges) ; translu-
cent ; light amber
clour, but a good
deal darker in cen-
tre, although
latter thinner than
edges.

per cent.

0-45

2-42

0.69

6-60
8 -84
060
3-75
0-9202

Biscuit even
thickness of :>
to 1 mm. even
amber colour ;
trans 1 ucent,
some air bub-
bles.

per cent.

0-36

2-69

0-33

2-92
93-70
0-16
100
0-9097

* By difference.

(26

202

PARA RUBBER.

Messrs. Schidrowitz and Kaye, in the Journal of the Chemical
Society, have dealt with the composition of Ceylon biscuits of
various thicknesses , and their analyses are given above ; other
analyses * by tlie same chemists show that rubber prepared from
Ceylon latex possessed from about 86 over 90 per cent, of caoutchouc,
when the moisture raucred from 5 to 9 per cent.

Specific Gravity of Raw and Vulcanized Rubbers.

Messrs. Clayton Beadle and Stevens (Chemical News, Nov,
15th and November 21st., 1907) give several determinations of the
specitic gravities of rubbers examined by them. They show that
the sjjecitic gravity of apparently similar bisoiiits, 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 lighter than others.

When dealing with vulcanized rubbers they point out that
there is a tendency for the specific gravity to increase on keeping,
especially if the samples have been fully cured. Over-cured
samples which had been kept for sometime showed high specific
gravities ; there was usually a loss in tensile strength with a
conspicuous increase in specific gravity,

Mr. ]M. Kelway Baniber has made a series of analyses of Para
rubber from trees of different ages, and the proportion of resin
is here shown ; —

Para Rubber from Trees of Different Ages.

Two yeais. Four years. Six Seven

A. B. A. B. years. years.

Resin .. 3-25% 3-60% .. 3-28% 2- 72% . . 2-75% . . 2- 10%

Eight years. Ten-Twelve years. Thirty years.
Resin .. 2-66% .. 2-26% .. 2-32%

Para and Other Rubbers.
It has been suggested that the addition of analyses of other
rubbers might be of value, and accordingly the following tables
have been draw up :-

Ceylon-fjrown Para, Ceara, ami Castilloa Ruhher. (1)

Para

Ceara

Castilloa

Rubber.

per cent.

Caoutchouc

.. 94-60

76-25

S6-19

K sin

2-0(5

10-04

1-2-42

Proteids

1-75

8-05

0-87

A.sh

0-14

2-46

0-20

Moisture

0-85

3-20

0-32

• India- Rubber Journal, 1st July, 1907.

(1) M. Kelwa Bamber, Committee of gricultural Experiments,
November, 1905

PARA RUBIiEK.

Pa/'a compared with Rubber from Landolphia.

203

(-2)

(3)

(^)

Landolphia

liaud()l|>luH

Landolp

hia Watsoniana

Kii'kii.

Petersiana

( Kast African rubber).

per cent.

Caoutchouc . . 80-1

67-7

67-2

Resin . . <) • 9

111

11-9

Dirt and insoluble

matter . . ") • 3

'^■4

8-0

Ash included

in dirt .. <>-31

1'2

1-3

Moisture. . . 7 • 7

17-7

12-9

Valued at

ValiK^d at

^'alued at

4/ -per lb. wlien

3 -per lb. w

hen 'li

!;3 to 2/4 per lb

fine Para 4/8

Para at 4 10

in 1903.

Para compared icith Ficus, Urceola, am

/ Rhynocodia Rubber .

(5)

(6)

(H)

Species Ficus elastica

Urceola

Rhynocodia

of Ficus.

(Bengal).

csculenta

Wallichii.

per cent.

Caoutchouc . . 1 !* ' C

84-3

80-5

86-5

Resin .. 49-9

11-8

9-8

6-5

Dirt and insoluble

matter . . '2-1

5-7

4.2

Ash included in dirt 0-79 . .

0-8

1-lG ,

0.48

Moisture . . 28-4

0-8

4-0

2.8

Valued at

V^alue 1 at

1 Id. per lb.

1/10 to 2/1

4/- per lb

3/6 i^er lb.

when Para

hi 1902

at 4/8

Chemical and Physical Properties of Rubber.
It has been previously pointed out, in the ''India-Rubber
Journal," tliat the physical characters of various oils, gums and
resins can generally be associated with ditferences in chemical
composition. A sHght change in the proportion of certain
chemical ingredients or reduction or oxidation of components in
a mixture, often appreciably affects the physical pro^jerties of
the products under observation. Tlie same may, to a limited
extent, be applied to various rubbers which regularly appear <jn
the market. An hicrease 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

(2) Bulletin of tlie Imperial Institute, June, 1904.

(3) Do. do. do. June, 1904 (rubber from Natal).

(4) Do. do. do. Jan., 19<>5 (rubber from East .Africn,).
(5-6) Bulletin of Imperial Institute, Sept., 1904 (Rubber from Burma).

(7) Teclmif-al Reports and Scientific Papcr.s. Imperial Institute, iy03.

(8) Bulli'tiuof Imperial Institute, \'ol. 1, p. 09, 1903.

204 PARA RUBBEK.

their chemical composition and ab^ociated pky«ical properties.
Chemical analyses even as submitted to-day, in their undoubtedly
empirical and undesirable form, allow us to sometimes distinguish
the botanical sources of certain latices and rubbers, though
the plants yielding them may not at the tnne be available
for botanical verification. But no one can deny that the
analyses of rubber as at present submitted often give no indication
of tlie physical differences which exist between samples of rubber
obtained from Para trees of different ages. This does not
necessarily disprove that a correlation exists between the chemical
composition and the physical properties of the rubber, but
suggests that the analyses do not distinguish the differences
between the components of the groups enumerated. We contend
that it is not sufficient to merely state the percentage of resinous,
albuminous, and caoutchouc contents in samples of rubber; this
grouping of most of the constituents and the calculation of
caoutchouc by difference does not give us any idea of the
differences which we are led to believe exist between the proteins
involved in the phases of coagulation and those which appear
in solution after the complete sei:)aration 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.

• Professor Dunstan, in his address before the British
Association in 1906, pomted out that the chemical analysis of
raw rubber as at present conducted is not always to be taken
by itself as a trustworthy criterion of quality and more
refined processes of analysis are now needed. In a recent
Bulletin of the Imperial Institute the Director 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 are 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 difft-rent origin has to be assumed. The i)hysical 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."

It is, however, the opinion of many that though the chemical
composition of rubber may exhibit considerable variation the
])hysical 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.

PARA RUBBER. 205

Resins.
In Para rubber the amount of resinous and oily substances
varies from 1 to 4 per cent., when obtained from mature trees.
Many analyses have been made of rubber from trees of various
ages and of different species. In the case of Castilloa dastica,
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 : —

Uesins\ in Rubber of Castilloa Trees.

From I'er cent.

Trunk .. .. .. .. 2-61

Largest branches .. .. .. 3*77

Medium . . . . . . . . 4 • 88

Young . . . . . . . . 5 • 8G

Leaves . . . . . . . . 7 • 50

A similar increase in resin in the rubber from young Castilloa
trees of different ages was also described, the variation being from
7-21 per cent, from eight -year- old trees to 35-02 in rubber from
trees three years old.

Weber concluded that it could scarcely be doubted that rubbe:-
from other kinds of rubber trees would exhibit similar relationships ;
subsequent research has not confirmed this contention as far as
Para rubber is concerned.

Resins in Various Rubber.
The following percentages of resitis in various rubbers are given
by Weber: —

Per cent.

Para ( Hevea brasilieusis ) .-. •• 1-3

Ceara ( M.nihot Glaziovii ) .. •• 2.1

Colombie (Castilloa elastiea) . . • • 3.8

Madagascar ( Landolphia ? ) . . • • 8.2

Assam (Ficus elastiea).. .. •• 1L3

Mangabe-ira ( Hancornia species ) . . • • 13.1

African balls ( Landolpliia ? ) . . ■ • 27.8

Messrs. Schidrowitz and Kaye Yn\ their note on the resins in
various crude rubbers examined by them give some figures which
tliey have obtained for the total alkali absorbed by the resins in
the rubbers described above. '•The results are expressed in c. c.
N. 10 alkali required to fully neutralize and saponify 1 grm. of the
resin in each case.

* Web.n', India Rubber and Gutta Percha Trades Joiu'nal, Sept. 29,
1902.

t Iiidia-Rubber Journal, April Sth, 1907.

8.83

6.70

16.61

—

6.03

27.03

17.54

3.21

206 PARA RUBBER.

The following figures were obtaiaacl: —

Uganda

Mexican

Ceylon .. 6.03 .. 27.03 .. .30.2

Malay .. 17.54 .. 3.21 .. 12.70

The low figures in the case of Ceylon No. 1, wliich was
appreciably different from the other samples, and in the case of
Malay No. 2, which was coagulated by nitric acid, are worthy of
note ; otherwise the figures for the ' various groups of rubbers
are fairly comparable."

The figures relate to the quantity of alkali required to fully
neutralize and saponify the resins in tlio various rubbers. The
resins are a highly (;omplex class of bodies consisting as a rule, of
a mixture of various constituents; different resins behave in diflferent
ways and their condition as well as quantity are of importance.
It is possible that some resins are not only not disadvantageous,
but possibly of advantage up to a certain point.

Removal of Resins From Rubber.
The resin content of crude rubber is a subject which has
occupied the attention of numerous chemists, owing to the
importance of this substance in the vulcanised product.

The amount of resin in various samj)les of rubber varies
considerably in some cases, even in different samples known under
thcsanic name the quantity may vary quite 50 per cent. As to the
value of rub])or freed from resin, opinions are somewhat at variance.
The Rheenisclier Gummiwerke — (cf. India-Rubber Journal,
February 1907) — claim to be able to phice on tlie market a rubber
which for all technical purposes may be considered free from
resin. An cxamhiatioii of these TesiM-fr''(' rubbers has been made
by Drs. Frank, Marckwald and Leebschuetz Avith the object of
determining whether the extraction of the resins from raw-washed
lubber influences the manufaetuiing process favourably or un-
favourably. They re])ort that the sheets of rubber obtained in the
ordinary way from the extracted rubber are in every case less
Kticky and more uniform than those from non-extracted material.
Further the extracted rubber was described as being brighter in
ap])earance and the smell characteristic of the several brands had
invariably disapi)eared. Physical tests were also made both witli
the extracted and non-extracted rubbers. V^aiious l>iar\ds of upper
('ongo, Madaga.scar and (Gambia rubbers were employed for these,
determinations, containing varying amounts of resin, ranging from
■i to 38%, which after extraction were reduced from 2 to 9%.

PARA RUBBER. 2(J7

As a rosiilt of thoir exporimotitson the rubbers from which tho
liroater jiart of t Ih^ resins liiid \m'v.u exlracled, they coneluded aa
follows: —

(1). The speeifie smell of the raw material is removed.

(2), Its stickiness also disappears completely by extvadion
of the resins, thus materially assisting mixing operations.

(3). The solidity of vulcanized goods made from extracted
lubbers of typical bad qualities is ijivariably greatly superior,
being sometimes as much as 50 per cent, better than the nou-
exlractcd rubljcr.

(4). The extraction of resin facilitates uniform qualities being
supplied.

The removal of resins from rubberr; 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 resinous contents. It is, however, a subject of
interest to all rubber growers as besides producing the advantages
already mentioned it would eticct a reduction in cost of transport
and be of importance to the manufacturer. Pure plantation rubbers
containing loss than 4 per cent, of resin would, however, not
require such treatment

Thoug;]i the various "Plantation" and "Wild" rubbers which
arrive in Europe contain resin in quantities varying from 1
to about 40 per cent., they appear to be all subjected to the same
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 lend-
ing themselves best to this purification process. The complete
extraction of these resins fi'om lubber requires many days. The
presence of the resinous impurities influences the behaviour of
the rubber in i)ractical working and also the stability of the finished
article. Owing to th.e supposed detrimental effect of the resins after
vulcanization, no efforts are spared to reduce them to the desired
f|uantity in the inferior brands of rubber. The extraction of some
of the resinous liodies from the latex of certain plants is a subject
which, though crowded with difficulties, might profitably engage
the time of the jiroducer in the Tropics.

Albuminoids.

The albuminoids, which either alone or with other sub-
stances lead to putrefaction, exist almost entirely in solution
in the fresh latex. Their removal from commercial rubber on a
large scale is considered by many to be almost impossible.

* Weber, I.e., p. 3.

208 PARA RUBBER.

Weber suggested that an expeditious metkod would be to
centrifugalize the solutions, a method which has been dealt witli
when describing tlie machines used in preparing and purifying
rubber.

The addition of formaldehyde to some latices is supposed
(1) to prevent the coagulation of the albumen and (2) to cause the
india-rubber to collect on the top of the mixture. The proper
application of this reagent to Castilloa latex is said to free
the rubber from every trace of albuminous matter. It has,
however, been questioned whether, or not, the " caoutchouc would
coagulate or even coalesce, if all albuminoids were removed from
the latex.

There is a slightly higher percentage of proteins and resins in
Para 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 present in
he samples.

ASF.

Tliis impurity is present in almost negligible quantities —
0-18 to 05 per cent. (Jenerall}^, Para rubber contains O'i per cent,
of ash, as against 0'2 per cent, in other rubbers. Weber is respon-
sible for the statement ' ' that it may yet be possible to chemically
identify the brand of india-rubber 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 india-
rubber and the resinous constituents during the processes of
manufacture.

Spence, as a resuU of his analyses* of Funturaia rubber, con-
cludes 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, wlien exhaustive investigation of
the quantitative composition of the ash of the various brands
has been made, as a chemical metliod of distinguishing washed
rubber from difterent sources. The constancy of the mineral
constituents in waslu^d rubber is a point of considerable importance.

Potassium in Washed Rubber.

Spence in his concluding paragraph states "that the percentage
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

* India-Rubber Journal, September, 1907.

PARA RUBBER. 20d

of washing. In a sample of Funtumia elaslica latex it was present
in the form of solubl e salts of inorganic and organic acids and
composed about 75 per cent, of the ash of the latex on incinera-
tion, according to Spence.

The insoluble constituent present in rubber is a substance which
is free from stickiness, is remarkably tough, and lias moderate dis-
tensibihty. Its nature and importance is imperfectly understood.

There is a quantity of oxygen present in india-rubber, but the
proportion of tliis is, according to Weber, reduced practically
to vanishing point in successive purifying processes.

General Properties of Indiarubber.
Alkahes have not a pronounced action upon mdiarubber at low
t-eniperatures. Heinzerhng states that on prolonged digestion with
ammonia the indiarubber ])asses into the state of an emulsion,
in appearance closely resemblmg india-rubber milk.

The effect of chlorine, bromine, and iodine on indiarubber is
very comphcated, 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 india-rubber articles
commonly used. Strong sulphuric acid oxidises rubber ; strong
nitric acid attacks rubber \ngorously, forming at first a yellow com-
pound which is subsequently decomposed. The effect of oxygen on
crude and vulcanized rubber is to cause deterioration, a compound
known as Spiller's resin being formed. Crude indiarubber,
particularly just after it leaves the washing machine for the drying
room, is apt to suffer considerably from oxidation durhig the drying
process, and it seems possible that similar changes may occur after
coagulation and pressing in the tropics.

Though india-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 the rubber frmn
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 of indiarubber is small.
Though india-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 india-
rubber at temperatures below 270°r., but sulphur mono-chloride
readily reacts with it at ordinary temperatures.

The elasticity, resihency, colour, and odour of rubber vary con-
siderablj-, according to the age of the trees, and the methods of
collecting, coagulating, and curing the product. Rubber from

(-7)

210 PARA RUBBER.

mature trees, if well prepared, is of a pale amber tolour, has a
slight odour, and is very tough ; badly-pre})ared rubber or that
from young trees is frequently speckled, emits a foul odour, and
may on keeping become sticky, plastic, or brittle.

Action of Heat ois India-rubbek.
India-rubber becomes sticky if subjected to high temperatures.
It passes into quite a Hquid state at ordinary temperatures under
certain conditions; if sound rubber is subjected to 170 to ISCC,
it becomes more or less fluid. The melting point, if rubber can be
said to have one, is much liigher than this if the resin Jias been
extracted. It is important that all diying and coagulating processes
should be so devised as to ensure the temperature being regulated,
and a maximum temperature considerably below that just quoted
should be guaranteed.

India-rubber articles, if exposed to high temperatures, are apt
to lose their strength, and to' develop '^either sticky or brittle
properties.

■^i'^^mi^^-^

CHAPTER XVI.
PURIFICATION OF RUBBER.

Analyses of waslied and dried Para rubber — Purification I)y the manufac
tnrers — Lawrence's process for cleaning crude rubbers — Loss in the
manufacture of brands of Para rubber — Loss on washing ru)>ber—
Oily and resinous substances and ash in various rul)bers —
High loss undesirable — Purification of plantation rubber — Descrip-
tion of rubber washing machme — The machine at work — Washing
scrap and dirty rubber — General accoimt of washing machines —
Steam-jacketed rollers— The cut of rollers— Illustrations showing
various types of rubber machinery and rollers of different patterns
— Macerators for bark shavings — Characters of washed rubber-
Rapid washing and dryin

HAVING dealt with the properties of the latex and the various
methods of preparing rubber therefrom, it is now necessary to
consider the important question of the condition of the rubber when
it enters tlie market, and the processes through which it passes in
purification. It is possible that much time and trouble may be saved ,
and at the same time a rubber of higher quality be produced, by carry-
ing out certain purification processes in the initial stages. The con-
dition of tlie rubber when it arrives in Europe is well-known to most
cultivators, as it undergoes no changes during transit if it has
been properly prepared. An ordinary sample of washed and dried
fine Para rubber may contain the following: —

Rubber

fl-t'O per cent

Resinous matter

2-5 „

Albuminous matter

.. 3-0 „

Mineral matter

0-5 ,,

Very often grades of washed rubber, prepared carelessly,
contain nearlj'- 20 per cent, of impurities, and in the case of " scrap "
ru})ber the (juestion of purification iiiay become a serious one.

Purification by the Manufacturers.
The scraps of fibre, particles of sand, abundance of resins,
albuminoids, and mineral matter are not required in tht^ finished
product, and the mechanical and solublei mpurities are, as far as pes-

212 PARA RUBBER.

sible 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 through the washing machines, the rollers of
wliich 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 temperature. 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, but if the temperature is raised too high the resins may
be converted into sticky substances, which will cement the rubber
and mechanical impurities and thus render it impossible to remove
the latter by this process.

The fragments rejoin and finally form a porous sheet which,
when dry, is known as washed rubber to the manufacturer. The
rubber may then undergo various masticating, mixing, and vulcani-
zing processes.

Lawrence has, according to the "India-Rubber Journal,"
November 20, 1905, brought out a patent method for cleaning
crude rubber, which is to some extent applicable to ordinary
scrap rubber on estates. The process consists of first grinding
or macerating tlie rubber., and then subjecting it to liquids or
solutions having different specific gravities. It is specially devised
to deal with the extraction of the fibrous and woody matter in
crude or scrap rubber.

Loss IN Manufacturing.

The actual loss in these purification processes is often surprising.
The loss on washing some of the Para rubber collected by the
natives 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 : — (1) fine Para, 10-15 per cent. ; (2) extra fine,
the carelessly smoked pieces, 15-20 per cent.; Sernamby, rubber
pulled from tlie 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 samples containing 2-2 to 2-9 per
cent, of resin and 0-27 to 0-29 per cent, of ash. According to John-
son, the loss from fine Para is from 10-15 per cent., whereas that
from the plantation biscuit, sheet, crepe, &c., rubber is only
about 1 per cent. Weberf states that tlie fine ]*ara rubber from
the Amazon District shows a loss on washing of 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.

* India-Rubber Journal, April 28, 1902,
t Weber, i.e., p. 122,

Fedcrateil Enginccritifi Co-

A RUBBER WASHING MACHINE.

SHOWING WATKH PIPKS AXI) CRKPi; KlTUHKIt.

PARA RUBBER. 213

Different brands sliow a variation in the amount of the loss on
washing as indicated below, and the composition of the impurities
are clearly put forward by Weber : —

IjOss on Oily ami Resinous

Brand.

Wasliiug.

Substances.

Asli.

pov cent.

j)or cent,

per cent,

Ceylon

Para, liard euro

1
15

3-0
i> • I

0-5
0-;->

Para, soft ciu-e

,.17

•2 • ,-)

0-.3

Ceara

.32

2<)

2-74

Borneo

2 2

2*2

The loss on wasliing is estimated by determining the'yieldof dry
washed rubber obtainable from a known bulk of crude rubber. This
loss consists mainly of water, salts, wood fibres, and mmeral
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 some cases it is
semi-resiHent and slightly sticky, sometimes hard and brittle, and
in a few cases is white and powdery in appearance. The estimation
of these oily and resinous constituents is best carried out by
extracting 5 to 10 grammes of the perfectly dry washed rubber
in a Soxhlet extracter by means of acetone. Many persons
assume that the percentage of resinous matter in indiaruJjber is an
indication of the care bestowed upon it by the producer. This
is not correct, as the resinous matters exist in the latex as the latter
flows from the trees. The variation in the resin 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 miJJvs 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 * read before the
International Congress of Applied Chemistry the following interest-
ing 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 brands of
rubber, has practically entirely disappeared from the market.
What little still occurs under the name is an altogether inferior
product,"

Purification by the Growers,
The use of machinery is bound to become more general
when more rubber is collected; the means adopted for straining,

* India-Rubber Journal, July 20.

21 4 PARA RUBBER.

purifying, and coagulating the latex will minimise the loss which
normally occurs in the manufacturing process. Already machines
for washing the rubber by the grower have been strongly recom-
mended by autliorities m tlie East.

Rubber Washing Machine.

In rubber districts a modified wruiging machine is frequently
used, which, though it is light and cheap, cannot usually be recom-
mended as efficient. If a sufficiently powerful and well-equipped
rubber washing machine is used, the effect is not only to free the
rubber from a large proportion of the soluble impurities, but to
produce a dried product possessing good physical properties

A Rubber Washing Machine.

The following is Mr. P. J, Burgess's account of the new rubber
washing machine : —

"This machine consists essentially of two 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 J inch to practical contact.

' The rollers revolve at different speeds and are driven by
power transmitted from belt and pulley through gear wheels to the
rollers themselves.

" The axes of the two rollers may be on the same horizontal
plane, more usually one is slightly above the other; a stream of
water flows over the surface of the rollers all the time they
are in use.

The Machine at Work.

" When the machine is used, freshly-coagulated lumps of rubber
are put between the rollers, which are separated about \ inch. The
rubber is ])assed tlirough several tunes, the rollers being gradually
approximated to each other, and the rubber be(K)mes (compacted
and to some degree hardened. At the same time the effect of the
differential rate of movement of tiie two roller surfaces is to subject
the rubber to a shearing stress, which stretches and tears it to pieces,
and it is here that the peculiar property of rubber is clearly seen.
The elastic stretching and rebound kick out any gross meclianical
impurity that may be present, and when the machine is used on
scrap rubber there is a perfect shower of dirt, pieces of baik and
wood being thrown out from the fiont of the machine. Freshly-cut or
torn surfaces of rubber reunite on contact and pressure ; for this
reivson the fragments, into which the rubber is torn by tlie machine,
reunite and emerge as a continuous sheet. At the same time the
stream of water thoroughly washes out any impurity soluble in
water that may be left in the rubber. The final product w a coherent

HEAVY WASHING MILL

PAHA RtTBBER. " 216

but granular sheet of rubber, the thickness of whicli can be regulated
by the distance left between the rollers. The function of tlie
machhie is thus three-fold. : —

♦' 1. — It ejects mechanically any solid impurity.

" 2. — It breaks up the rubber, and subjects all portions of it to
he washing effect of flowing water.

"3. — It produces a graimlar thin sheet of unifcnm thickness,
which is clean and whicli can be easily and rapidly dried.

" The interests at stake are so great that I may be permitted
perhaps to put in condensed form the advantages of the use of a
washing machine in preparing rubber. —

* 1. — The rubber produced will be as pure as it possibly can be
without costly chemical treatment.

"2. — The rubber, being pure, will be of uniform quaUty.

" 3. — The rubber, being washed, will be ready for immediate
use by the manufacturer.

" 4. — It will effect a saving of labour to tlie planter by
eliminating the petty hand labour involved in preparing rubber in
small plates, rolhng the sheets by hand, and manipulation of the
small biscuits.

*' 5. — There will be an enormous saving of time in drying the
rubber ; this will involve a saving of storage room and labour in
looking after the rubber when drying.

' ' 6. — There will be no possibihty of putrefaction of rubber in
drying, or discolouration by the growth of mould, the substances
which putrefy or which feed mould being to some extent eliminated,

" 7. — The machines will clean and deal efficiently and economi
cally with scrap.

" 8. — ^The washed rubber can be turned out of any length or
thickness required, and will be easier to handle and pack. It keeps
better than the best of the biscuits prepared in the old way."

Washing Scrap and Dirty Rubber.

" But the use of a washing machine driven by an engine is not
by any means confined to freshly-coagulated latex. In dealing
with scrap and dirty rubber its efficiency is very marked. The
scrap is cleaned, mechanical impurities are ejected, dirt and mud
are washed awaj^, and the scrap is finally turned out in a form pre-
cisely similar to that taken by the first-class rubber, and in a state of
purity which is only a trifle inferior to it. Witii rubber from Ficus
elastica or Rambong the machine deals in a similar manner.

216 PARA RUBBER.

and an easy and simple method of treatment of tliis hither*
to intractable latex is made possible. Great ditficulty has been
found in dealing with Rambong up to the present, because it cannot
be coagulated in sheets in the same way as can Para rubber. If, how-
ever, the thick latex be churned, beaten, or violently shaken it coagu-
lates in a great lump, and to treat this lump in the old way, to dry
and render it fit for export, has been a matter of great difficulty and
of many months. The lumps may be treated at once with the
washing machine and thin sheets produced, which are clean and
which rapidly dry without difficulty."

Since Burgess publish ed the above several firms have brought
forward macliines of various types, but the lecture by Burgess
was one of tlie first of its kind and tiie lengthy extracts^ are,
for that reason, here used

General Account of Washing Machines.

The various washing macliines on the market are constructed
on somewhat similar principles ; they c onsist essentially of two
revolving rollers geared to run at different rates and are so
arranged as to allow a good current of water to flow between
the rollers when the rubber is being washed. The rollers are
usually adjustable to enable the cooly to accommodate a given
thickness of rubber ; a large machine should be capable of
turning out 100 lb. of rubber per hour.

The surfaces of the rollers vary considerably, the majority
of those used for freshly-coagulated rubber having comparatively
shallow grooves. The rollers through which the soft, spongy
rubber first passes are usually diamond, square, or straight, cut,
the indents always being relatively shallow; the final rollers
through wliicli tlie stretched and washed rubber is passed are
usually smooth. Spirally cut rollers are rarely used for freshly-
coagulated rubber on plantations, though manufacturers use
them for purifying the raw rubber on arrival, at the factory. The
accompanying illustration, showing plain , diamond, square, screw,
straight and spiral cut rollers, has been kindly lent by Messrs.
David Bridge and Co.,

Most rollers are solid and cold; some steam-jacketed rollers
have, however, been recently placed oji the market by Messrs.
Robert Warner & Co., London; these heated rollers make the
rubber very soft and turn out material which can be easily blocked.

Macerators for Bark Shavings.

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, a

I, I ;' S

BRIDGE'S TYPES OF ROLLERS-

SHAW'S RUBBER WASHING MACHINE-

PARA RUBBER. i>17

washing machine provided with a pair of spirally cut rollers is
usually employed. The bark shaving.s are usually first steeped
in tubs of water for several days in order to soften the tissues ;
the bark may be more rapidy destroyed by the use of small
quantities of caustic alkalies. Before rubber can be etfectively
separated from the shavings it is generally necessary to pas.'^
tiie whole mass through the rollers many times ; the rubber
iinally obtained from bark shavings is generally dark in colour,
and, even though it may have been well wa*^hed, lias a tendency
to becoming sticky on the surface.

In April, 190S, I saw some horizontally-fluted rollers, made
by Robinson & Co., Salford, effectively purifying scrap rubber on
Culloden estate.

Characters of Washed Rubber.

If the washing process has been properly carried out the
rubber should dry rai^idly and give a pale amber-coloured final
])roduet. The unevenness depends upon the cut of the rollers and
the number of times the rubber lias been operated upon ; often
the rubber has been torn and stretched beyond all requirements.
Thoroughly AA'ashed rubber does not usually show any signs of
mould or tackiness; crepe — probably on account of the washing to
\\ liich it has l)een 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.

Rapid Washing and Dbyin'g.

The question of rapid washing and drying is one of the most
serious with which large rubber growers have to contend. The pre-
paration of small quantities of rubber by the '' setting pan " method,
and drjang in spacious chambers, is not applicable to large estates.
It would appea • advisable to collect the latex in large tanks -until
a sufficient!}' large quantity has been obtained, coagulation being
prevented by the addition of reagents ; the large quantity of latex
can then be rapidly coagulated, and the fresh rubber put througli
a washing machine, which will turn the rubber out in such a condition
that it can be properly cured in two or three days. I am indebted
to Messrs. David Bridge & Co., Francis Shaw & Co., and tlie
Federated Engineering Co., for illustrations showing the type? of
wa«;hing machinery commonly supplied.

(28)

CHAPTER XVII.

VULCANIZATION AND USES OF RUB HER

Vulcanization of rubber — Heat, sulphur, and india-rubber — The heat
cure and cold cure — The Effects of resins upon vulcanization of
rubber — Low percentage of resin in Para rubl^er — The problem
of using latex direct — Hancock's experiments — Colouring latex —
Sulphiu'ising latex — B amber's experiments, difficulties on estates
and in factories and commercial value — Suljjhurising freslily
coagulated rubber undesi cable — Quantity of india-rubber in common
articles, roller coshering, steam packing, tyre cover, tobacco
l)ouch, garden hoso — The composition of rubber tyres — Analyses
by Schidrowitz and Kaye, showing percentage of india-rubber
and substitutes — Analyses by Beadle and Stevens, showing
composition of solid tyres — Uses of rubber — Purposes for which
])lantation rubber is useful and useless — The direct use of plant-
ation I'ubber — Tests with vulcanized plantation rubber — Important
results by Beadle and Stevens — Synthetic rubber — Its non-existence
— Misuse of the t Tm "Synthetic rubber" — Artificial rubbers,
theLi' general characters and uses — Composition of artificial rubber
— Improvement of low-grade rubbers — Substitutes for rubber —
Use of vulcanized linseed, rape, poppy seed, cotton seed and
castor oils— Disuse of rubber.

A ORE AT part of the rubber industry is dependent upon the
material being in a vulcanized condition, the change being
effected by mixing sulphur in one of its many forms with the masti-
cated rubber and then heating the mixture. Usually only from 4 to
5 pei" cent, of sulphur is used in ordinary vulcanization, but in the
production of ebonite or vulcanite as much as 20 to 40 per cent, of
sulphiu- may be used. A more complete distribution of sulphur
througli the india-rubber may be possible if a solution containing
sulphur l)e 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 otlier reagents
containing varying amounts of sulphur.

The )nain factor upon which the action l)etween sulphur and
india-rubber depends is heat ; there is no action 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 eft'ected
at temperatures little above lOO^^C.

PARA RUBBER 219

In this process a great part of tlic sulphur becomes fixed by the
india-rubber, but not the whole of it ; there is always a certain quan-
tity of sulphur in a free state in vulcanized articles of commerce.
Ordinary sulphur, or various compounds of sulphur, may be used in
this process, and the articles manufactured from such material are
usually considered to be tougher, more resistant, and less easily
melted.

The Heat and Cold Cures.

Rubber may be vulcanized either by what is known as the heat
cure or the cold cure. In the heat cure the rubber and sulphur are
mixed together by machinery and the temperature raised to 300^ F.,
when chemical union takes place between the components, and vul-
canized rubber is formed. The whole of the sulphur does not com-
bine with the india-rubber, but if the high temperature is maintained
for a long period, more and more of the free sulphur enters into com-
bination and produces a darker and tougher vulcanized product.
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 witli the rubber, with which it readily
combines at ordinary tempr?atures, and produces a vulcanized
product suitabU^ for the manufacture of goods which would bo
damaged by high temperatures. Sulplim" monochloride is a liquid
at ordinary temperatures, and on account of its violent action with
india-rubber is diluted by dissolving in carbon bisulphide before
being used for vulcanizing.

The Effects of Resins upon Vulcanization of Rubber.

The presence of resins in Plantation and wild Para and other
rubbers has an important bearing upon the reactions that take
place during vulcanization. According to the "India- Rubber Jounal"
of August 13th.. 1906, Dr. R. Ditmar has made a careful compari-
son of several brands of rubber, and communicated the results
of his observations to the " Gumnii Zeitung. " The amount of
resin contained in each sample having been first determined, 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 tine Para, containing 144 per cent, of resiji,
was completely vulcanized and was very elastic. It was only
surpassed in the latter respect by Mozambique balls and spindles,
jMassai balls, and Cej'lon Para. The behaviour of the Mozambique
balls was remarkable, for altiunigh it was coJisiderably richer in
resins and was not fully vulcanized, it shelved a greater elasticity
and strength tlian tlie Para rubber with only 1'44 per cent, of
resin. The cause of this is probably to be sought more in tho origin
of the rubber than in the resin it contained. The same properties

220 PARA RUBBER.

were also observed in Adeli balls, Lewa rubber, and Soudan
twists, although they did not contain such a high percentage of
resin as the Mozambique balls. It is therefore concluded from these
experiments that as long as 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 vulcaniza-
tion of the rubber ; at the same time the origin of the rubber
is also of great importance in this respect. More accurate
information on this subject, however, would be obtained by vul-
canizing Para rubber, for instance, Mitli increasing amounts of
resin extracted from one quality of rubber. Accordingly, experi-
ments were eventually carried out in the following way ; Para
rubber containing 3'28 per cent, of resin was well washed and
dried, mixed in live gram lots \\ ith 10 per cent, of sulphur, and
worked up with increasing quantities of Congo resin, extracted
from finest blaek Upper Congo rubber with acetone. Ten such
samples were vulcanized for 45 minutes at 145 deg. 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 exten-
sibility of the rubber rose from 3-9 to 5*7. The first live samples
(3-15 per cent, added resin) were well vulcanized, the remainder
were vulcanized throughout, but became gradually softer as the
l)roportion of resin increased.

The percentage of resins in Plantation and Wild Para is, how-
ever, usually mucli smaller than in many of the other rubbers
here mentioned and the injurious effect of excess of resins may,
as far as Para rubber cultivators are concerned, be dismissed.

Using Latex Direct.

Many attempts have been made to use the 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 little advance has been
made in this line of research. Hancock * 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 lie 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 wliiting, ochre, brickdust, emery powder, were added
according to recjuiremetits. As the result of his labours Hancock
lijially decided not to make any further efforts in cionnection with
the utilisation of latex direct, mainly owing to the difficultiei he

• lnclia-Rul)l)cr Juurnul, Oct. 8th, 1906.

PARA RUBBER. 221

experienced in obtaining it in sufficiently large quantities and in
ood condition. In his summing up lie states tliat: — • "altliou<_'Ii
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 worth-
less matter will probably prevent its ever being used extensively.
Before the difficulty of dissolving ordinary rubber was overcome
it was tliought that the hquid, if it could be obtained, would bo
invaluable; but now, all things considered, the dry material for
nearly all the purposes of manufacture, is the cheajDest and most
easily applied, altV.ough to persons unacquainted with practical
details this may appear enigmatical.

Baniber has, in a somewhat similar manner, made- samples of
rubber belting, flooring, mats, etc., by using sulphurised latex in
conjunctioji with waste coir dust and coconut fibre. The dust and
fibre are cheap and obtainable in large quantities in Cejlon and
the latex re(|uired is very small. When tlie^e arc^ thoroughly
mixed and combined with sulphur, tlic mass dried and vidcanised,
a strong, hard, and pliable article is said to be obtained.

Colouring Latex.

The latex can also be coloured by organic* dyes, such as
mctylene blue, etc. , and the poisonous colouring matter be thorough-
ly mixed with the rubber instead of being put on the outside as is
so often done in the nuinufacture of childrens" toys. It is interesting
to note that though Hancock pointed this principle out in 1857,
the method has not been taken up on commercial lines in any of
the countries where rubber plants are cultivated. Among the more
notable colouring substances used by rubber manufacturers are
verniillion, lithopone, golden sulpliide, red and b.'own oxides, zinc
white and otiiers, maiiy of which contain combined sulphur.

Sulphurising Latex.

The subject of the treatment of the latex, with solutions whleh
will precipitate large quantities of free sulphur in a fine state of
division, is one which has been nmch ventilated during recent times.
In the process outlined by Bamber, t ^^ solution of suljihur is
added to the fresh latex and thoroughly stirred ; on treatment witli
acid sulphur is preci])itated and the latex coagulated, the resultant
rubber being minutely permeated with the finely divided particles
of sulphur. Antimou}- solution and the sulphur may, according
to Bamber, have a strong antiseptic effect on the rubber. The
complete mixing of sulphur with the latex while the latter is in a

* Tropical Agricultimst, October, 190G.

t Tropical Agricultmist, Colombo, Octoter, 19l6.

222 PARA RUBBER.

liquid condition is intended to do away with this process at a later
stage in the manufacture of the rubber goods, and to thereby eflfecfc
a saving in time and power.

It should, however, be pointed out that the processes througli
which raw rubber has to pass in the manufactories are not de-
signed solely for the perfect mixing of sulphur with rubber, but
for the removal of various impurities — economically impossible
once the latex has been sulphurised — and the admixture of various
compounding ingredients, known only to the trade.

If the direct treatment of the latex is to be of avail to the
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 original components from the latex so sulpiuirised.

The treatment of the latex while in a li(juid condition neces-
sitates 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 brasiliensis. It is also maintained that
the addition of ammonia and formalin — especially tlie former — is
not always accompanied with constant results, and the latex, owing
to its very varied composition, is difficult, to standardize. These
difficulties, though somewhat serious, can be overcome once the
j)rocess of treating the latex with sulphur and other ingredients
is pronounced a commercial success.

The idea was criticised in the '" India Rubber World " and the
"India-Rubber Journal"; the editors stating hat the process,
though of interest, was not one wliich could be regarded as being of
much commercial value to manufacturers.

SULPHURISING FrKSHLY-CoAULLATED RlUBER.

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, rolled or pressed into any desired shape. On some estates
experiments have been made with the freshlv-coagulated rubber

PARA RL'BBhJU. 223

while ill this condition, mixtures of sulj.hur with other in<rredients
being added and after thorough mixing pressed into blocks or
sheets and dried. It is olnious that rubber so treated
possesses the maximum amount of resinous, protein and other
imi)urities and if washed after the additional compounding'
uigredients liave been mixed with it, a loss of the latter may be
oeeasioned.

The mixing of foreign ingredients with rubber, if ever
considered desirable, can, as far as ordinary estates are concerned
be best carried out when the rubber is in the freshly-coac^ulated
spongy state ; to adopt such a treatment, on the plantation, with
the rubber after it has passed tluough the washing machine would
not be attended with satisfactory results.

It has been claimed that the addition of these ingredients
prevents the rubber from becomhig soft or tacky, and that" there is
an improvement in the physical properties of the rubber • the
tackiness or softening may, liowever, 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 manufacturin-/
operations m th? tropics there appears to be verv little in favour o"t'
addmg a small percentage of certain vulcanizing and compounding
ingredients to the freshly-coagulated rubber : the writer certainlv
does not know of any manufacturers who have called for rubber
m that condition.

Quantity of India-rubber in Common Articles.
The important part which india-rubber and sulphur together
with other substances, play in the manufacture of articles ik common
use, IS little less than remarkable.

The following analyses are given by Weber •

12 3 4 3

Roller Steam Outer Cover Tobacco Garden
Covering. Packing, of a Tyre. Poucli. Hose.

T^i.-o.uu percent, percent, percent, percent, percent.

Indiarubber .. 24-49 12-73 54-70 50-22 31-->9

treesulphur 1.23 2-10 0-88 0-27 1-^3
bulphur of vulcani-

zation .. 084 _ 1.99 2-7-> 2-1-.

Mineral matter .. 72-33 62-81 41-08 2-19 26-28

Organic extract .. l-io 2-82 1-34 4-88 7-34

Carbonaceous matter — 19-53

Fatty substitute .. — __' _ 07.0, ^g.^^

Chlorine in rubber.. _ _ _ 2-50 2-20

The presence of as much as 50 to 54 percent, of india-rubber
in an ordinary tyre and tobacco pouch, the use of nearly 30 per

224

PAilA RUBBER

cent, of fatty substitutes in garden hoses, and over 70 per cent, of
mineral matter in roller covering made from fine Para, should bo
noted.

Rubber in Tyres.
A considerable amount of analytical work liar; been done in
Europe witii the object of determining the composition of rubber
tyres. Schidrowitz and Kaye* conducted an examination of tyres
of representative makes and the following are analyses of sov^eral
brands which they investigated : —

T,\]iM-; ].— Coven.

Mark.

Part of tyre

Tread,

Tread.

Body.

Tread.

Condition, Ac. ...

Good.

Very
badly
flaked
and "sun-
cracked. "

Good.

Badly

cut, but

not "sun-

craeked. '"

(Jood ;
little
used.

Specific gravity: apparent ...

li:ri

1-2901

0-9.567

1-272

1 -3000

India-rubber

l)er cent.
(K)-IO

iier rent.
.-53-07

per feiU.
83-76

per cent.
05-00

7-90

per cent.
30-82

Orp;anic extract..

5-80

3-13

4-54

9-50

Sulphur : Total ..

.'j-SO

4-00

t-90

9-80

2-78

Sulphur of Vulcanisation...

:i-i4

2-12

2-94

3-97

0-97

Sulphur : Free ...

2-30

1-27

1-96

4-2-2

1-32

Sulphur in mineral matter

0-36

0-61

1-61

0-49

^Mineral matter ..

i9-:30

39-80
Nil.

0-80

17 30

50-80

Fatty substitutes

Nil.

Organic extract : rubber ...

7-70

5-50

510

10-80

23-50

Co-enicient of vulcanisation

4-50

3-90

3-50

G-10

314

Sulphur (excl . mineral sul-
phur): rubber...

7-80

6-4

5-80 12-6

7-4

Oxidation (" sun-crackinp;"
test)—

m g r m s. of oxygen
absorbed per.sq, cm. ...

(a) 4-8
{/>) 4-1

1-8

(«) 6-6
(b) 5-9

Schldrowitz and Kaye, concluded that manufacturers are by no
means agreed as to the quality of rubber and mineral matter to
bo used; certainly the analyses publislied show that the proportion
of rubber is very variable in the covers examined.

* Journal of the Society of Chemical Industry, February 28th, 1907.

PARA RUBBER. 225

Clayton Beadle and Stevens* sub.sequenfcly gave an .account of
tlieir investigations into the composition and value of tyre rubbers;
tlio following are results obtained with solid tyros : —

Sample. 1. '_'. 3. 4.

Rosins, jSrc, (acetone extract), per cent. ... 9.i» 8.6 7.2 7.4

India-rubber substitutes (alooliolic potash

extract), per cent. ... ... ... 10.-_> 8.9 9.1 11.7

Mineral matter (ash), per cent. ... ... 3S."» 39.-2 40.7 33.2

Tntlia-rubbor (caoutchouc) by difference, per

cent. ... ... ... ... 42. :i 4.S.3 4:^.0 47.7

Total sulphur (calculated on caoutcho\ic),

percent. ... ... ... ... 7.S 9.0 lu.u 11.:?

Free sulpliur (calculated on caoutchouc),

pel" cent. ... ... ... 3..1 3.7 -"".G G.l

Combined sulphur (calculated on caoutchouc),

percent. ... ... ... ... 4.3 5.3 4.4 .'5.2

Tensile strength, grms. ... ... ... 37 IS 2')09 34i>;? 3217

Elongation at rupture, per cent. ... ... .'jo 3S.") .")2 45.."*

Elongation under a strain of 15: K) gnus,

percent. ... ... ... ... 23..j 24 24. .j 26..J

U.sEs OF Rubber.

The ases of Para rubber liave been greatly augmented in recent
years by the increased production of automobiles and accessories,
and it is difficult to accurately forecast what the demand for rubber
will be when it is more generally adopted for wheeled traffic and
public passenger vehicles in many parts of the world. It has also
been largely used in the making of tiling, balls, boots, articles of
clothing, instruments, belting, &c., and "solution." Plantation
rubber is said to be preferred by many manufacturers for
"solutions," on account of their being able to ase it direct with
the solvents without purification.

Exactly how much plantation rubb^u- is u.sed for certain
purposes is not known, but in view of the fact that somebody
must buy and use plantation Para, even though it is described
as, and known to be, inferior to fine hard cure, tlie India-Rubber
Journal | circularised maiuifacturers and asked them if they
would state for what purpo.ses they found ])lantation rubb?r (a)
u.seful 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 hi used ; whilst another firm, which frankly pointed out
that competition in business did not permit their inforjning the

* Chemical News, August iJnd, 19U7.

t India-Rubber Journal, September 23ril 1907.

(2!i)

226 PARA RUBBER.

public for vvliat 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.

Plantation rubber will, undoubtedly, he more largely used
when it can b3 procured at cheaper rates and from older trees.

Direct Use of Plantation Rubber.

Stevens * discussing the question of the direct treatment of
plantation rubber for mastication and mixing, says it is one of
considerable importance. If the latex was 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 arrived in the
excellent condition in which it is now being received from well
equipped estates. This would save the manufacturer the
softening in warm water, followed by the washing and drying
operations, the latter being a particularly slow process, especially
if the rubber is stored for the purpose of allowing it to regain
the peculiar physical condition in winch it yields tlie best results
on vulcanization.

It is, of course, open to question how far it is permissible
to draw general conclusions as to the behaviour of caoutchouc
under manufacturing conditions from experiments with small
quantities carried out on a laboratory scale, but if the latter
may be takf-n as a guide it should be possible to masticate and
mix washed and dried plantation rubber without any preliminary
treatment, save perhaps a very short sojourn in the drying rooms
to remove superficial moisture, and provided also the rubber is
put up in a convenient form for treatment between the mixing rolls.

Tests with Vulcanized Plantation Rubber,

Messrs Clayton B'^adle and Stevens have published, in a
recent issue of the Chemical News, an account of their experi-
ments with plantation rubber. They vulcanized samples of
plantation and fine hard Para rubber; tho pr^du'-ts from the
former were clear, t-arisparont, yellow to brown shade when viewed
through sheets 1 mm. thick ; the latter were much darker and less
transparent. TlIv, average tensile strengtli and eltngation of
vulcanized plantation rubber samples was 3203, and that of the

* Kubber Cultivation in the British Empire, (page 94), Maclaren and
Sons, Shoe Lane, London, 1907.

PARA RUBBER, 227

vulcanized iine, bard Para 3013; the average elongation at the
moment of rupture for the plantation lots was 131 and for the tine
hard Para 12-7. They therefore concluded that the plantation
product would prove equal to Amazonian Para ; they also sub-
sequently 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 aie very interesting but at the outset it should
bo pointed out that Beadle and Sievei.s dealt probably with the
bsv b]o(k phontation rubber on the market. A ])crusal of their
work gives one t\w impression that plantation rubber is quiie
equal to, if not better than, hr^rd fine Para. Practical
manufacturers, whose experience in this regard is surel)^ unique,
are, we believe, of a decidedly different opinion. It is believed
that the latex obtained from mature plantation Hevea trees and
coagulated in the proper manner is not in the long run, likely to
prove in any way inferior to the wild Para latex, and the
reasons for the lack of "resiliency" or "nerve" of much of the
plantation product must be looked for in other directions,
particularly in the tapping of immature trees, etc, and of the
employment of methods of coagulation which are not quite
suitable.

The same chemists * have since jjublished 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. Tlie hard-
cure Para supplied by the manufacturer yielded lower figures
for tensile strength than the plantation rubber. They finally
point out that difi'erent forms of plantation rubber differ
ma erially from one another and suggest that planters will
require to consider carefully whether the form in which they are
shipping their rubber is that which yields the bjst results to
the manufacturer.

Synthetic and Artificial Rubbers, and Substitutes.

During the latter part of 1907 the writer was frequently con-
sulted regarding various artificial rubbers then on the market and the
current rumours respecting synthetic rubber. Confused criticisms and
comments have recently appeared in some sections of the Press, and
as the subject does not appear to be yet clearly or fully understood, a
simple explanation of the position can, advantageously, be given hero

V^ulcanization Testa with Plantation Rubber, Chemical News, Oct.
I8th, 19(17.

228 PARA RUBBER.

Definition op Synthetic Rubbee.
As pointed out elsewhere * synthetic rubber maybe defined as
one built up by chemical means from various substances , and poss-
cssuig all the chemical and physical properties of natural rubber.
As a standard for natural rubber one may take that obtainable
from Hevea hradliensis.

Now, natural rubber consists, chemically, of veiy 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 bo
specially considered here. These have been dealt with hi the chapter
»>n tliis pait of tlio subject. It may not be Avell known to many,
but it sliould, nevertheless, l)e bcu'ue in mind, that some of tlie fore-
most rubberchemistsof the day frankly acknowledge then- ignorance
regarding tlu^ exact chemical constitution of some of the substances
wliicli normally occur in almost every sainplo of natural rubljer.

The substances referred to hi such empirical terms as "resuis"
and "proteins" are in themselves highly complex bodies, tlie com-
ponents of whicli, though recognised, and conveniently grouped
together, are but little understood. Caoutchouc, the 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 nevei' been made successfully on a com-
mercial scale. A small (quantity was once obtained by an eminent
chemist, but concerning it there lias been very little progress, of
commercial importance, to record up to the present time.

How can it then be possible, suice we do not fully understand
the chemical composition of the various components of natural
rubber, to have synthetic rubber already on the market l

One of the greatest chemists of the day recently declared, that
he was incredulous of the production of synthetic rubber, commer-
cially, at any price. The writer can confidently state that we has
never seen a sami)le of synthetic rubber (the term is here used in
tiie strict, scientific sense), though time after time he has received
samples of artificial rubbe;s, and so-called rubber substitutes.
Furthermore, he can emphatically declare that he does not know
of the production, on either a laboratory or comuicrcial scale,
of synthetic rubber.

It is obvious that no one can, for a moment, say that it is
impossible to ever discover substitutes or substances having some
of the characteristics of natural rubber; that would, to say the
least, be under-estimating the possible achievements of chemical

* Iiulia-Ruljber Juuinal, October, 1907.

PARA RUBBER. 229

science, if not idly attempting to negative what lias been achieved
long ago. Every one must know that natural rubber alone, tliough
it is very tough, would be of little use if not compounded with
various substances; mixing is one of the most important branches
of the rubber industry, and many developments may be expected
in that direction.

Misuse of Terms.
At the same time one strongly objects to the gross misuse of
the term "synthetic rubber"; its application to any substance
Avhieh is remarkable for its lightness in weiglit <jr elasticity is nob
justitiable, and in my o})inion should never he allowed. Boiled sea
weeds 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. High-grade and low-grade natural
rubbers, when mixed with balata or gummy extracts, may show
considerable iinproveinent in physical properties, and this may bo
especially true of resinous, low-grade, rubbers; but no competent
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
vulcanized or oxidized oils, or to materials which have as their
basis a varying proportion of natural rubber.

Artificial Rubbers.
Artifical rubbers and rubber substitutes are known by the
score. They are substances usuall}^ derived from some organic
source, and generally possess one or more of tlie physical
characteristics 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 defined
as substances containing, essentially, aouantity of natural rubber,
together with other sul)stances, and the latter as materials derived
from sources other than crude rubbers.

Composition of an Artificial Rubber.
The desu-c to place on the market a comparatively cheap
composite mixture having physical properties similar to raw
rubber Ls strongly marked. From time to time samples for report
and analysis are received ; when they pos.sess characters of value
to rubber manufacturers tliey usually contain, as an essential
component, a propoition of rubber, reclaimed or otherwise. In the
" Gummi-Zeitung " an analytical account is given of material

230 PARA RUBBER.

submitted a.s " an artificial rubber prepared from vegetable fibres"
to Drs. Marckwald and Frank. The following details are given
regarding the composition of this substance : —

Per

Cent.

Moisture, volatile at 100 deg. C.

12.86

Acetone extract

61.50

Which consisted of —

Saponifiable constituents

9.44

Unsaponitiable constituents

... 49.88

Sulphur

... 2.18

Mineral constituents

• •••

7.16

Sulphur combined with rubber

...

3.00

Rubber substance

15.48

100.00

In such a sample it is obvious that 100 parts of rubber are
(u)mbined with about 19 parts of sulphur. The mineral constit-
uents are said to have consisted largely of aluminia, containing
i{uantities of iron oxide, 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 tiio term.

Improved Low -Grade Rubbers

There has been recently placed 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 su bstance — 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 from the factories. It is obvious, however,
that in the preparation of this class of rubber, materials, very ex-
pensive in themselves, have to be used, guayule rubber alone
standing at one to two shillmgs per lb. Furthermore, the
necessary ingredients are obtained from plants which grow very
slowly, and the method of extraction is often 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 exhaust-
ed before many years 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."

PARA KrBBER. 231

Substitutes for Rubber.
Rubber substitutes are already largely employed in the
manufacture of certain india-rubber articles and large factories
have long been established 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
the vulcanization of india-rubber 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 little use if it were not mixed and compounded with
various substances.

Terry's Opinions of Substitutes.
Terry* in dealing with india-rubber substitutes states that
the efforts inventors have made to discover or prejiare a substitute
for rubber have been very noticeable, but up to the present tijne
no real substitute has been discovered. In his opinion the substi-
tutes which have so far been used have no status beyond that of
cheapening ingredients and not until some substance, which on
admixture with rubber cheapens it without at the same time
reducing its quality, 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 benefitted no one except those
who are professionally concerned with patents and that the
present prospects of wealth for the discoverer of a rubber substitute
are largely illusionary. It is, however, pointed out that in the
manufacture of rubber articles where elasticity is not really
required, e.g. waterproof goods, door mats, etc., certain substances
may be legitimately used which will not impair the efficiency
of the manufactured article.

In Ceylon the Telephone and Telegraph sections of the Post Office
Department have, according to Mr. Cook, 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 so peculiar in regard to the soil and the atmos-
phere, that the engineers have not made up their minds as to the
desirabihty of the change from vulcanized rubber insulation.
Nevertheless, cheap substitutes are being used in cable work in
many^parts of the world.

* India-Rubber and its Manufacture ; by Hubert L. Terry, 1907. . ;

232 PARA RUBBER.

Burgess, as a result of inquiries made during 1905 in Europe, was
able to state 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 demand-
ing 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.

Guttapercha has been tried both in Ceylon and India, but the
concensus of opinion is that for tropical installations it is far inferior
to indiarubber.

CHAPTER XVIII.
KINDS OF PARA RUBBER.

Plantation and fine liard Para — Differences between Plantation and
Wild rubber — Inferiority of plantation Para rubber — Opinions
of india-rubber manufacturers on plantation rubber — Observa-
tions by Burgess — The smoking method of plantation rubber
— Pre\('nti>n of putrefi.ction— Chemical and phj'sical tests —
Similarity in chemical composition and differences in physical
properties — Physical properties of rubber from Ceylon and
Malayan estates — Forms of plantation rubber — Packing rubber—
Ventilation of packing cases — Biscuit &nd sheet— Size and shapes
— Crepe — Worm — Conversion of worms into crepe — Lace — Flake
— Sera]3 — Purification of scrap rubber — Colour of plantation
rubber — Block rubber — Method of preparation — A co'.nmunication
irom Lanadron estate — Size of blocks — Blocking dry rubber-
Presses • for blocking rubber — Brown and Davidson's press —
Slinw's block press — Bridge's presses — Kinds of plantation rubber :
manufacturers' advice to planters — Small lots of rubber: brokers'
advice to planters — Analyses of plantation rubber.

Differences between Plantation and Wild Rubber.

THE comparison of the kinds of Para rubber may appropriately
be prefaced by a few remarks regarding the differences
between Plantation and Wild or fine hard Para rubber, the former
being obtained from the newly-planted trees in tlie Tropics and the
latter from the wild trees in the Amazon District.

Tlie methods of preparation in the East are such that Plantation
rubber is made much purer than fine hard Para ; it contains very
little, if any, moisture, and is obtained with or without the use of
chemical reagents. It is, of course, usually obtained from younger
trees than fine hard Para. Plantation rubber, when placed on
the same market as "wild," obtains a higher price, weight for
weight, because of the small quantity of water and other impurities
present, the loss on washing being only about 1 per cent, as against
10 to 20 per cent, for some grades of fine hard Para rubber. The
extraction of the impurities from the latter rubber is not always very
troublesome, and if allowance is made for the large quantity of water
it contains the price realised is really much better than that for
Plantation rubber free from moisture.

(3U)

234 PARA RUBBER.

The preference of manufacturers for purified fine hard Para
rubber is said to be due not so much to its being obtainable in large
quantities, as to the fact that its properties are much more superior
and constant.

The "India-Rubber World" recently stated tnat several
manufacturers in Great Britain were unable to give their opinion
as to the value of Plantation Para rubber, but they all seem
agreed that there was a wide variation in its quality as received
in England.

Examples are known of specimens of pure Para Plantation rubber
which in two years have resolved themselves into a gummy substance
void of all the desirable properties of india-rubber, whereas samples
of purified fine hard Para rubber have been perfectly sound after
seventy years. Plantation rubber is usually regarded as want-
ing in resiliency and recuperative power, but when put on the
market as clean biscuit, crepe, or worm rubber, is eagerly bought
on account of its purity and, therefore, adaptability for "solution"
purposes.

The "India-Rubber Journal" (Sept. 23rd, 1907) when discussing
the inferiority or otherwise of Plantation rubber stated that they
had long held the opinion that the age of the trees, the frequency
of tapping, the method of coagulation, and the use of antiseptics
were factors which influenced the quality of crude rubber. The
trees on most of the eastern plantations are quite young, they are
often tapped in a manner which does not allow the constituents of
the latex to mature, the coagulation is effected by using reagents
which do not give the best results, and the use of antiseptics in tlie
latex and rubber has only been recently prominently brought for-
ward; under such conditions, one may expect that the quality of
plantation rubber cannot be equal to that of hard fine Para, but
must continue to improve year by year as the trees get older and
tlie systems of rubber production are improved.

Some prominent firms place Plantation rubber in a superior
position ; in order to ascertain the views of European india-
rubber manufacturers on tlie value of plantation rubber the same
Journal made a direct appeal to them, and requested them to state
whether they considered plantation rubber inferior, or otherwise,
to wild rubber, for general manufacturing inirposts. The results
of that enquiry were that .'}0 per cent, of llie manufactuicrs declar-
ed in favour of plantation rubbe/ and 70 per cent, p t)nounced it
inferior to average wild rubber.

Tlie "India-Pvu])ber World" (March 1st., 1907) in discussing
this ((uestion ])ointed out tliat though a wise manufacturer would
not dare, leaving out'of the question the interest on investment, to

PARA RUBBER. 2^^

Inly 50 tons of cultivate:! Hevea rubber and store it for six months,
because he would be afraid of the very appreciable deterioration in
(|uality, yet lie \vc»uld buy thousands of tons of upriver lino
I'ara and store it witli a full knowledge that it would not grow
worse in storage, but would grow better. This is surely one of
the most vital considerations and one to be commended to the
planting community as deserving of t heir tiist and best attention.

The opinion in many quarters is that the use of cliemicals
such as acetic acid, formalin, &c., should not be continued if the
Plantation rubber can be effectively prepared and purified by
mechanical means.

Burgess, in his report upon a visit to Great Britain to investigate
the india-rubber industry and its relation to the growth and prepara-
tion of raw rubber in the Malay Peninsula, states that the
manufacturers who had tried Plantation rubber from Ceylon and
the Straits were agreed that the " rubber was good and very service-
able, but that it was by no means as good as South American fine
Para, either hard or soft cure. The Plantation rubber is lacking in
" nerve," it works soft between the masticating rollers, and its keep-
ing quahties are inferior to South American Para. After vulcani-
zation the tensile strength is less, and the elastic recovery of shape
after deformation by stretching or compression is less perfect than
South American Para under precisely similar conditions. He
further points out that the Plantation rubber shows an inferiority
from 8 to 15 per cent, compared with wild Para, and that this
inferiority is not only in the physical properties which are capable
of immediate measurement, but also in the keeping quahties of
the rubber, the plantation samples often tending to become soft
and gummy whilst wild Para remains tough and elastic after
many years' keeping. Burgess suggests that the superiority of the
wild Para may be due to the fact that the rubber trees of South
America which are tapped, are selected both by natural and artificial
selection, and therefore only the best and oldest trees are used as
som-ces of rubber. This idea is original, but does not appear to be
supported by results obtained from the old trees at Henaratgoda
and Peradeniya, where only the first tappings gave tacky or soft
rubber ; or by tlie observations quoted by Jumelle.

The Smoking Method and Plantation Rubber.

In a communication to the Press dated March 22, 1906,
essrs. Lewis & Peat point out that consignments of biscuits have
arrived in London in a heated and sticky condition, and raise the
query as to whether the present mode of preparing biscuits is the
best. It is pointed out that Amazon-grown smoke-cured rubber
is still the standard, and haa for a record of 50 years maintained
its reputation for elasticity, strength, and durability.

236 PARA nUBBER.

It has been pointed out, elsewhere, how Para rubber is siuoked
in Brazil, and in addition to the nuts of specified palms certain
antiseptic reagents such as creosote, dilute hydrofluoric acid, and
corrosive sublimate have been mentioned as being of use in the
preparation of rubber. It has also been shown that rubber prepared
from trees 30 years old may, if not properly dried, become quite
as heated or tacky as that from young trees. If a larger
proportion of moistm-e is left in Plantation rubber, putrefactive
changes will be more apt to occur, and the use of antiseptics either
by direct application to the latex or by smoking or coating the
rubber will be imperative. In any case, the coating of the rubber
particles or smoking the freshly-prepared rubber crepe or sheets
Avith any antiseptic is always an advantage as far as the keeping
properties of the rubber are concerned ; moat of the heating or
tackiness in Plantation rubber is due to bacteria which can
be prevented from spreading by the use of antiseptics ; if not
destroyed they will lead to putrefactive changes in rubber with which
they are brought into contact. It is really a disease which in
unsmoked rubber can certainly be spread by contact ; but whether
it is more likely to develop on rubber from young or old trees, is still
a point to be determined. If the consumers will accept the Planta-
tion rubber, prepared by the use of antiseptics as described, the
producers will find no difficulty in meeting their requirements ; in
fact, several Ceylon estates have, for some time past, sent their
rubber to Europe in the smoked condition, but whether better
average prices for large quantities have been obtained is not known
to the public.

The subject of Plantation versus wild fine Para has been
discussed in a recent issue of the "German Rubber Trade Journal,"
by Gustave van den Kerckhove, and, as in other communications,
the writer points out that fine Para has not been deposed by the
plantation product, and that the former probably owes its better
physical properties of elasticity, durabifity, &c., to the creosote
emitted during the smoking process.

Chemical and Physical Tests.

The inferiority of Plantation rubber is commonly attributed to the
trees being immature as compared with those in the Amazon District.
But it has been previously shown tliat in the Amazon District trees
are tapped wlien they are 15 years old ; wlien forest Para rubber
trees are 25 years old they are described as having reached maturity.
In view of these facts it is interesting to reflect on the chemical
analyses of rubber from trees 4, 6, 8, 10-12, and 30 years old, given
elsewhere. These analyses have been made from rubber obtained
from Ceylon-grown trees, and it is fortunate that the age can
be guaranteed. They show very clearly that the variation in chemi-
cal composition between the rubber from young and 30-year-old

PARA RUBBER. 237

trees is insignificant, and that the reputed defects of rubber from
young trees cannot be explained from the differences in the chemical
analyses given. There is as much variation between the chemical
composition of samples of rubber frotn trees of the same age as be-
tween those given for the material obtained from trees 4 to 30 years
old ; ordinary analytical methods do not ai)pear to give many indic-
ations of the great differences in physical properties. From these
and other considerations one feels compelled to seek for some otlier
tests, of a physical nature, whereby tlie rubber may be scientifically
classified, and whicli will allow of the value being calculated on a
sound basis. Colour cannot be accepted as a guide, though prefer-
ence seems to be given to the pale amber colour by many manu-
facturers ; only in the case of really bad samples can odour be taken
as indicating quality, as the best biscuits have often a cheesy putres-
cid smell which is more or less transient. In this chapter it will
be seen that certain physical tests have been devised, and the results
obtained with samples of Plantation rubber from the East are given.
It is not impossible that the physical properties of rubber will ulti-
mately be associated with the quantity and nature of the ingredients
indicated in the numerous chemical analyses which have been quoted.
At the present time the valuation of different kinds of Plantation
rubber is not usually based on chemical analysis, except by a few
firms on the continent of Europe, but mainly on appearance and
physical characters

The "India-Rubber Journal" recently pubhshed a series of
reports regarding various samples of Plantation rubber from the
East. Opinions as to the strength and general value' of cultivated
rubber have shown considerable variation. Though the conclusions
embodied in the previous paragraph may be taken as represent-
ing the opinions of a large number of manufacturers, yet it has
frequently been stated on good authority that cultivated Para rubber
was equal in tensile strength to native-cured Para , and after vulcaniza-
tion gave very good results. The differences in strengtli noticeable
in Plantation rubber are usually ascribed to the tapping of young
trees and irregularity in mixing the latex from trees of dififerent ages ;
the latter cannot help but occur on small estates, where only a small
proportion of the trees are even ten years old.

Regarding certain samples of Plantation rubber it has been
stated that when worked on the mill the light coloured samples
gave the odour pecuUar to fine Para when prepared without the
use of smoke.

On the mill they prove to be much softer than dry sheet
Brazihan Para. They also take the "compound" much more
rapidly than the Amazonian variety. To assist in comparing
the tensiles obtained from the several brands of Plantation
rubber the data are presented in tabular form. The term

238 MUA liUBlSE^.

" Tensile " means the pounds required to break I in. by ^ in. in
section of the compounded rubber.

CEYiiON Samples. Other Samples.

Conditions.

Steam

Til IK

rressurc.

Mill.

lb.

Uorana-

Sudu-

Kalu-

Bukit

Pata-

kaudo.

ganga.

tara.

Kajah.

liug.

121

99 .

. 83

113

138

. . 115

136

143

133 .

. . 104

140

127

121

. . 107

125

From tlie above analyses the same Journal proceeds to state : (1)
" That Ceylon Para when used to denote the Oriental source of fine
Para means a grade lacking in uniformity , when the tensile strengtli
is considered ; (2) the curing qualities of Ceylon fine indicate that it
has a decidedly slower action than the South American product ;

(3) all the Oriental samples are much softer and less nervous than
the Occidental types."

Forms of Plantation Rubbee.

Having compared the differences of Plantation and BraziHan
rubber, it now remains to deal with the various forms of the
cultivated rubber; they are briefly (1) sheet, (2) biscuit, (3) crepe,

(4) worm, (5) lace, (6) flake, (7) scrap and (8) block rubber.

Packing Rubber.
In packing Plantation rubber the packages, which sliould be
strong and well hooped, should not exceed one to two cwt. in
weight ; a little Fuller's earth can, according to some authorities,
be used. It is not advisable to pack the rubber between paper.
The rubbers should be graded and all "heated" material kept
separately.

The desirability of ventilating cases in which plantation rubber
is shipped appears to be very questionable. Some manufacturers
liavc suggested tlxat planters should ship their rubber in air-tight
cases, but on the other hand a few planters have liad cause to
legret having adopted that system, owing to the arrival of their
lubber in Europe m a heated condition. It is obvious tliat block
rubber has an advantage over sheet and crcpo in so far that pro-
portionately less surface is exposed to the ah- ; one might, therefore,
feel inclined to argue that packing in air-tight cases, to minimise
oxidation, would be advantageous. But one must realise 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 tliere is any tendency
towards tackiness at the time of packing the whole consignment
may arrive as a treacly mass.

Photo by H. F. Ma<mUlan.
KINDS OF PLANTATION PARA RUBBER-
(1) shkkt: (2) BISCUIT : (:^) >S: (4) wijums ; (5) lace.

PARA RUBBER. 239

Biscuit and Sheet Rubber.
Biscuit and sheet rubber are commonly met with, and are
prepared by allowing the latex to set in shallow receptacles, with or
without acetic acid, and washing and rolling the cake of rubber which
appears at the top. The biscuits are more or less circular and the
sheets rectangular in outline. They are sometimes pressed together
to form blocks ; the sheets, on account of their shape, lend them-
selves to more economic packing than many other forms.

According to many London brokers there is a tendency for
shipments of sheets of rubber to be taken in preference to biscuits,
those having a clear amber colour and measuring about 2 feet by
1 foot having obtained high prices. Biscuits wliich were clear and
pale amber-coloured have obtained high prices.

An adviser to Messrs. Lewis & Peat is of the opinion that biscuits
and sheets will have to be abandoned in favour of balls or other
forms hke those in which fine Para arrives in Europe, aa the former
are very hable to become heated or tacky. He argues that " the
very form of thin biscuits lends itself to heating when under pressure,
whereas the ball shape and thick biscuits are far less liable to this
change ;" he prophesies that when the mbber is arriving in tons
the defects will be very evident by the state the material arrives in
and that even if the rubber does not get heated on the voyage it will
inevitably do so if stored for any length of time in the warehouse.
He gives as proof of Ms theory that the same thing occurred to
certain other rubber, and the remedy in that case was making it
into large balls.

Sheets measuring 24x 12 inches or more and y^ to ^ mch in
thickness are '-eceived with favour in Europe.

Size and Shape. &c.. of Biscuits.

In many instances the biscuits, on drying, curl up at the edges
and present an objectionable appearance. This can to some extent
be overcome by pressing them in a vessel of definite outhne
before subjecting tliem to the rolhng process ; after rolling, the
cakes partake of the shape of the vessel in wliieh they were pressed;
if the margins of the latter are correctly made the tendency to
curl and become wavy in outline is not as noticeable.

Biscuits and sheets are usually very pure, and can, without
waslnng, be used for " solution " work by the manufacturers ; the
material is practically ready for the naptha bath on its arrival in
Europe. It has been stated that the material from Ceylon sliriuks
about 1 -4 per cent . , and that it is not hked for cements. In past times
it lias been very irregular in quality, sometimes being little better
tlian elastic gum , sometimes sticky and only equal to recovered rubber
in elasticity. Tlie rubber biscuits from old Para trees are tough and

240 PARA RUBBER.

elastic, and much of the irregularity referred to might to some extent
be obviated by not mixing the tappings from trees of different ages.
If the irregularity in quality is allowed to continue, it may spoil
all prospects for use of our rubber in fine work, such as thread, blad-
ders, &c., and if the "solution" market should, at the same time,
become overstocked the position might under such circumstances
be embarrassing to rubber planters.

Biscuits should be made from j^ to ^ inch in thickness and 10
to 14 inches in diameter.

Crepe Rubber.
Crrpe rubber differs from the foregoing on account of the stretch-
ing 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 very uneven in thickness, and hke lace and
flake rubber dries very rapidly. On account of its purity it has been
well reported upon in Europe, and owing to the efforts of Burgess is
likely to come to the front in Malaya. Crepe rubber has been
described in Europe as "fine pale, strong, quite clean, and in good
condition." The material has been sold at a good price, but on
account of the washing and re- washing which certain manufacturers
subject all rubber to, it has been questioned as to whether the extra
labour involved in its preparation will be paid for by the higher
price. According to the ' ' India-Rubber World ' ' of December 1 ,
1905, very few consumers then looked upon this form of rubber
with favour, most of them preferring to do the washing themselves.

The crepe may be prepared in lengths of 3 to 6 feet, width
5 to 12 inches, an 1 be graded according to colour.

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 quality of the rubber is much
more difficult to tell in this form ; but the prejudice seems to be
wearing off." In any case it will always rank as a relatively pure
rubber, and will allow of the conversion of scraps and other kinds
to one class of uniform standard.

Messrs S. Figgis & Co., in a letter date:l October, 1907, state
that they advise the preparation of all plantation rubber, whether
first class or scrap, in the form of crepe and are evidently moro in
favour of this form than even block rubber.

Worm Rubber.

Worm rubber is essentially the product obtained by cutting
irregular sheets of freshly-coagulated rubber into ihin worm-liko

Lent by Maclaren & Sons.
PLANTATION RUBBER IN LONDON-

BLOCK, SHKET AXD CREPE RUBliEll IN THE SAIJC ROOM.

531

i/i

'^^

-2

■«*

LiJ

■^

<liJ

Lii

PARA RUBBER. 241

rods of unequal length. The Michie-Golledge machine is used to
coagulate the latex ; the fresh rubber is rolled to express the
water, and the irregular cakes are cut up by means of large shears,
(»r machinery The fresh rubber being cut into such fine parts dries
({uickly ; the ''worms" can be economically packed in ordinary
lea boxes.

Lewis and Peat, in their report on Phxntation Rubber for 1905,
state that worm rubber is not so attractive as biscuits or sheets, and
buyers are rather apt to treat it as a form of very fine scrap, although
the quality is every bit as good as sheet or biscuits.

Samples of worm rubber have, up to the present, received good
reports, the concensus of opinion being that the rubber so prepared
was very clean and contained very little moisture : once it has
established a name it might command a price equal to, or higher
than, biscuits on account of its purity and dryness. An
illustration elsewliere shows the freshlj'^-coagulated spongy mass,
which, after passing through the rolling machine also reproduced
elsewhere, is ready for cutting into '" worms."

By passing the dry worms through ordinary washing rollers
they are bound together into an even strip of crepe.

Lace Rubber.

Lace rubber has been prepared by Mr. Francis Hollo way , Matale.
It consists of very thin perforated sheets of considerable length.
In the preparation of lace rubber the latex is coagulated without the
use of mineral acids or application of heat, and after being
converted into '• lace" is dried in air kept at about 95° F. The
porous sheet is very thin, of a pale amber colour, and can be easily
pressed into biscuits or sheets of any desired thickness. Tiie " lace "
comes out of the machine in a continuous strip ; it is cut into pieces
6 feet long as it runs on to wire trays. The rubber is very thin
and dries rapidly ; it is maintained that it can be turned out ready
for drying within seven minutes of the latex arriving at the factory.
The time taken for coagulating the latex, conversion into lace
rubber, and drying ready for despatch is 48 hours. Mr. Holloway
assures me that only mechanical methods are adopted, a point
of considerable importance. The illustration elsewliere shows the
machinery used by Mr. Holloway.

Flake Rubber.

Flake rubber is quite a recent introduction, and I have to
thank Mr. C. 0. Macadam, Culloden, Neboda, for the information
on this form of rubber. Flake rubber w as made by Mr. Macadam by
placing small pieces of freshly-coagulated rubber in a small rolling
machine or washer, the corrugations of which run horizontallv ; the
rollers are close together and the cut rubber issues as thin strips.^ The

(31)

242 PARA RUBBER.

strips or flakes are very thin, and can be easily smoked and packed in
any form. The sample 1 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 compares very favourably with crApe or lace rubber.
Tills form is seldom seen on the liome market.

Scrap Rubber.
Scrap rubber is mainly the coagulated rubber obtained from the
incised areas, rolled into balls or made up into cakes. It may be
sent to Europe in 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 impur-
ities, obtains a high price.

Purification of Scrap Rubber.

Having regard to the opinions of manufacturers as to the
desu-ability of securing dry pure rubber, in preference to the wet
creosoted form, and bearing in mind the objections which
others raise against the use of rolling machinery hi the preparation
of crepe, the " India-Rubber Journal " asked the manufacturers
if thej'^ would state whether .they preferred crepe plantation
rubber to be sent as purified scrap, crepe or block, instead of in
the usual impure form containing a large proportion of bark and
other mechanical impurities. Only one firm suggested that the
scrap should be sent in the condition in which it is when picked
from the tapping lines. 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.
Evidently there was a strong desire for purity of rubber among
manufacturers, a demand which recently led the Governor of a
native state of Brazil to give every encouragement to the
purification of rubber before it left the Amazon Valley. As to
the form in which the manufacturers desire to receive the purified
scrap, the majority wei'e in favour of small blocks, and a few in
favour of crepe. The purified scrap rubber, seemg that it has to
be prepared by passing the scrap rubber together with pieces
(if bark, through the ordinary rolling machinery, cannot help
becommg mixed with juices pressed from the dead and living
bark cells. These are often such as to form a food supi)ly for
bacteria, which lead to the develoj)ment of tackiness in rubber
80 prepared. If it is prepared in the block forju this tendency
is minimized.

Colour of Plantation Rubber.

The colour of unsmoked plantation rubb.^r has evidently to
be taken into account by i>lanters. One London firm has
recommended that when shipping cr6pe th'i planters would bo
well advised to grade same into threa groups ; (a) pale and light

* s

F. ffollowii)/.

HOLLOWAY'S LACE RUBBER MANUFACTURE-

PARA RUBBEM. 243

amber coloured; (b) light coloured scrap; and (c) brown or
black crepe. In reply to a circular letter, in October 1907,
Messrs Gow, Wilson and Stanton stated that paleness was very
important and pale or clear, even, amb 'r-toloured rubber would
sell best ; Messrs S. Figgis and Co., at a later date suggested that
plantation rubber should be graded according to colour and
shipped as (a) pale and clear; (b) brown coloured; (c) dark
brown coloured.

Block Rubber : Method of Preparation.

During the latter part of 1906, after block rubber had
received special recognition at the Singapore Agri-Horticultural
Sliow ajid the Ceylon Rubber Exhibition, I received the following
communication from 'Mr. Francis Pears, which was immediately
sent to the Press, from Lanadron Estate : —

"Seeing the attention this has attracted both at the Singaitore
Agri-Horticultural Show and at the Ceylon Rubber Exhibition, it
would not seem out of place to fully explain the points hi its favour
and the details of its inception, as claimed b}"" the makers. Tlie
Prize '"Block" was manufactured by the Lanadron Estate of Muar
and the awards made by the Judges of both Exhibitions are fully
confirmed by the buyers at home who value this method of pre-
paration at 3 pence per lb. higher than the best sheet or crepe.
This will, of course, have the effect of inducing many planters to
take up this method of preparation, and it is to be hoped that in
doing so they will recognise that it requires good macliinery and
that good "Block" is not to be manufactured by immersing sheet
or biscuits in hot water and hydraulic pressing. This would only
imitate it in appearance and not in quality. The manufacture of
"Block" by the Lanadron Estate was conceived, in the first in-
stance, as a means of turning out a rubber of standard uniformity
in a practical manner, and one which would commend itself to
those manufacturing rubber on a large scale ; also to be a handy
form for shipping and for storage at home. That tliis has been
accomplished must be apparent to everybody. Added to this the
improvement in the quality undoubtedly establishes this as the
best means of manufacturing raw rubber hitherto employed. In
cojisidering any new methods referring to the treatment of raw
rubber, there are certain axioms to be considered, the most im-
portant of which are the following : —

1. Uniformity.

2. The eradication, as far as possible, of organic, and the com-
plete removal of inorganic, impurities from the latex

3. Acceleration durmg manufacture to reduce to a minitnuni
exposure to the air.

i. Small surface exposed after manufacture.

244 PARA RUBBER.

Ru er majiufactured witJi a view to those principles, besides
having the characteristics of a good commercial rubber, will give a
system which would appeal to anyone who takes an intelligent
interest in this industry and is desirous of establishing a factory
organisation on up-to-date principles, and where manual labour
will be reduced to a mininniin.

1. Respecting uniformity, the only way to accomphsh this is to
mix the latex and coagulate in bulk. It has been suggested that
the latex from trees of different ages shculd be kept separate, but
this proposition is not one that could easily be carried out in prac-
tice. It would be nmch better to start with the uniform standard ;
and if old trees really do give a superior latex, the product of the
estate must gradually improve with age. It has not yet been
proved conclusively that the older the tree the better the rubber,
although there are many indications pointing to this conclusion.

2. The eradication, as far as possible, of organic and the com-
plete removal of inorganic impurities in the latex: — the only way to
etfect this, as everybod}^ who is interested knows, is to wash the
freshly coagulated latex on an ordmary washing machine, such as
nianufactuiers use at home. In fact it is the only practicable
method of reducing coagulated latex in bulk to uniformity of size,
at th same time thoroughly washing every particle of rubber and
removing all mechanical, besides a good deal of the organic
impurities. Tackiness, of which we have heard a good deal lately,
and also mildew although of frequent occurrence in biscuits,
s'ldom if ever occur in properly washed crepe. This is strong
testimony to the fact that washing freshly-coagulated rubber
removes some of the organic impurities which arc detrimental o
the kce])ing pro])erties of the raw rubber. Whether in addition
to this it may be advisable to im])rcgnate the latex with some
antiseptic, such as snu)ke (creosote) formaldehyde, etc., is a
matter for further experiment.

3. Acceleration during manufacture to reduce to a min'mum
exposure to the air: — despatch* during manufacture can only be
accomplished by accelerating the drying process, as hitlierto this
has occupied periods varying from a few days to as numy weeks,
^\itll exposure all tlic time to the action of the air. Vacuum drying
is (he only practical solution totliis as it combines two very essential
points, viz : — rapidity, without an ex]»osure to tlie air. By this
jneans it is ])0Ssible to dry tlie rubber in two or three hours.
J"l\ce])tion has been taken to the use of Vacuum dryers, as making
lubber sticky, but this is only a matter of temperature which can
1)0 regulated mechanically. It is certainly rather a delicate oper-
ation and recpiires a juan in charge who thoroughly understands
the principles of (he ma<liine.

BROWN & DAVIDSON'S BLOCKING PRESS-

PARA RUBBER. 245

4. Small siirfiu'c exposiiro after mainifaclure: — affnr icinDval
of tlic crepe from the Vacuum drier i( is in a pliable cunditioii in
eonsetiueiiee of not being subjected to the haideniug inHuence of
air drying (oxidation) . In this state it is easily pressed into any
convenient shaped "block" and (he whole forms a perfectly
homogeneous mass, hermetically sealed, with a minimum surface
exposed to the air and light".

In the above decriptiou of the method brought forwaid by
Mr. Francis Pears, there are several minor points with which
many will be inclined to disagre?. but as the objei't is to draw
attention to the blocking process thess need not be he:e dealt with.

The above detailed account may be summarized as follows :
block rubber nuiy be made from biscuits, sheets, crepe, lace,
scrap, or worm rubber by pressing the material wliile in the soft
condition as it i^ in when removed from the heated vacuum
( hamber, 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 the action of
the air.

Owing to the arrival of parcels of wet block numy manu-
facturers ]iave sliown a disinclination to purchase rubber in tliis
form ; many of them have gone back to the old form of sheets or
the later form of crepe.

Tensile Strength of Block and Biscuit.

Messrs. Clayton Beadle and Stevens, (Chemical Xews,
November 15th, 1907) in their account of the specific gravity of
vulcanized, unloaded rubbers, state that the samjjles of block
examined by them yield a vulcanized product of greater tensile
strength tlian the sample of Ceylon biscuit.

Size of Blocks.

The original Lanadron blocks were about 10 x 10x6 inches
Mr, Francis Pears advocated the preparation of blocks about
one cubic foot, so that two could go to a (ase, with a thin part -
tion between them: such a block would weight about 50 lb. and
would therefore be equivalent to about 200 biscuits. The reasons
which Mr. Francis Pears gave in sujDport of the idea of making
such large blocks were (1) the thinner the blocks the more
hydraulic less'^s required, or less time nmst be given to pressin*'
each block, and (2) several thin blocks or slabs packed in one ca.se
would be IJrmly stuck together on airival in Europe and would
re([uiie considerable eft'ort to separate them. Several London
firms, h owe v^er, have suggested that the blocks should n(»t be so
thick and state that rectangular slabs, would he wel<ouie;the
thinner blocks are handled \\ ilh more ease.

246 PARA RUBBER.

Blocking Dry Rubber,

Block rubber can, of course, be most effectively made by
pressing the freshly coagulated latex, or the partially dry and
soft rubber fiesh from the vacuum driers ; but it is also possible
to make a block by pressing biscuits which have been kept in ihe
dried sta'e for several mouths. On one occasion some of the
Henaratgoda biscuits, ten weeks old and perfectly dry, were
placed in a mould and subjected to enormous pressure in a large
hand screw press ; the pressed b'scuits were kept in this condition
for two nights and one day — 30 hours in all — and then removed;
the block was almost as perfect as the best sample sent to the
Peradeniya Rubber Exhibition from Lanadron Estate, all traces
of Ihe separate biscuits being superficially destroyed and only
feebly distinguishable when the block was cut in two. If the
dry rubber in passed through heated rollers it is softened and in a
condition fit to be blocked.

Pkesses for Blocking lUrBSER.

Freshly- coagulated rubber is soft and spongy and can be
blocked without the use of complicated 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 well-
made 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
liave 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 i)resses 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.

Brown & David.son's Press.

Messrs. Brown and Davidson, Ceylon, showed a wooden screw
]H ess at the Ceylon Rubber Exhibition in J 9(16. 8ince that time
the presses have been improved and hi a specification of a hand
screw press, given by the above firm in their catalogue of Plantation
rubber machinery, it is stated that the (1) j)ress is made of cast iron
bolted to the bas(^ plate and strongly ribbed up all round the four
sides. The ca.st is in four pieces, all the jobits are machined and
firmly bolted together and the whole securely fixed to the base
plate. One section can quickly be reiao\ed for withdrawing the
rubber " Block"'. Tiie four sides of the picss arc all machined
ijiside and have smooth surfaces so that no part of tbe rubber
touches any rough or uneven part while being blocked. The
double motion ratchet gear is made of cast iron, caj)stan
machin(Hl all over, bored and fitted to the pressure screw, and is
provided with a cast iron socket.

PARA RUBBER. 247

Tlio pii'ssuie may he applied by the steel hand lever when
ni(i\(*d ineitlier direction.

Blocks of 12 ill. square by 9 in. to 10 in. in thickness can be
made in t!iis machine, but it is often desirable to have blo-.ks or
slabs made, 12 hi. square by 2 in. thick, more or les-?,

Shaw's Block Press.

Messrs. Shaw and Co., Manchester, have placed on the market
a compact liydraulic press. It is * claimed that, in their press,
thu-e are no working parts liable to get out of order, which is a
great consideration when tlie nativ^e labour usually employed is
taken into account. An illustration of this pre^^s is given else-
where. The toj) is hinged for charging and emptying, and can
be arranged to produce any size of finished block. The three
presses of the plant in question are arranged for producing
blocks 9 in. square by 3 in. thick. The cavity filled with rubber
before pressing being 9 in. square by 9 in. deep. Xame plates
are supplied • o fit the cavities by means of which the name of the
plantation is impressed on each block of rubber j)roduced. The
press is operated by a small hand pump as shown, fitted with a
safety valve which allows the water to circulate as soon as the
required pressure is attuned in the press. For smaller plants
Messrs. Shaw supply machines of smaller construction and made
for driving either from line shafting near the floor level, or by
means of belting from overhead shafting.

David Bridge's Presses.

Messrs. David Bridge and Co., Manchester, 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 cottcred to it,
on which are letters for branding the bio :3k rubber. The box is
detach iblc, therefore any number of boxes can be used with the
one press. Each box is fitted with two strong wrought iron
Ijridles, with four powerful screws. After the crepe rubber has
left the vacuum dryer, it is pressed in the box, and when under
pressure, the bridles are brought o/er to an upright position.
The screws are then brought down on the top of the false
platten, the cotters are knocked out, leaving the rubber
under pressure, and the screws run back clear of the box ; the
latter is then removed and run on to the lower shelf of the
vacuum dryer for a period to set. When quite set, it is

* India- Rubber Journal Sept. 23rd., 1907.

24S PARA RUBBER.

again removed from the vacuum dryer. The bottom of the box,
which is hinged, then allows the block to be forced out by the
four vertical seiews.

This press is also Htted 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. A convenient size is 11 inches by 9 inches, and
the tliicknes-! of the block is about 4i inches. Tlie total weight
of this press is about 17 cwt., with one box, and it can 1)0
dismantled so easily that there is no difficulty in transporting
f he various parts to their destination.

The press can also make a block of any tluckness from I
in. to 6 in. depending upon thefiriit packing of the crepe in the box.

Bridge's Hydraulic Rubber Block Press.

Messrs. David Bridge & Co., of Castleton, have patented a
hydraulic rubber block jness 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 suitable leather 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 hj^draulic pump, operated
})y 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 ])illars, secured by hexagon nut-; to
the head and cylinder mentioned.

The underside of the mullet is so prepared as to admit of
the namepla';e, for branding the rubber.

" The table is arranc^ed 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.

The press can also be supplied, without the hydraulic hand
pump, and arranged to be supplied from any hydraulic main that
may be already in existence, or separate power-driven hydraulic
pump could be supplied, with accumulator for feeding a battery
of presses.

bridge's blocking press.

SHAAV S BI.OrKIXfi PRESS.

HAND BLOCK PRESSES.

PARA RUBBER. 249

The total weight of this press is about 45 cwt. with one box.

Kinds of Plantation Rubber: Manufaoturees' Advice.
The various forms which have been here described liave now
been known to manufacturers for several years, and the advantages
and disadvantages of each publicly discussed on several occasions.

The " India- Rubber Journal" pubhshed the views of manu-
facturers on tliis 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 block, crepe, sheet
and biscuits were the predominating types on the London market,
yet tlie original biscuits still appealed to certain manufacturers,
apparently because they could b(^ 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.

As far as the producer is concerned, biscuits and sheets are
prepared in the same manner and at the same cost, but they prefer
the rectangular forni 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 where vacuum driers
are not in use ; the use of any quick-drying apparatus would,
however, enable the planters to place their rubber on the market
in these forms in a very short interval. To the planter there
is another objection against biscuits and sheets : they must
generally be prepared in small pans by the slow-setting process,
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. Thos3 who prefer plantation
rubber in the form of sheets specify that the sheets should be
fairly thin : one firm also suggests that they should b ) two to three
feet wide by two to three yards long. Very few of ihe manufacturers
then stipulated that they preferred the plantation rubber to be
hi the form of crepe, though they did not, at the same time,
emphasize their objections against rubber m that form. It is
of interest to note, however, that the two forms which appeared
to receive most approval were biscuits and block.

Perhaps when more firms have tried crepe and block they
will give us th-Mr opinion of its value. Those who have tried
the latter suggest that a convenient size for the b'ooks would be
6 inches squa "e ; all agree in suggesting that the thickness should
not exceed 1^ inches and a dia.neter of not more than 1| feet.

Small Lots of Rubber: Brokers' Advice
According to the "India-Rubber Journal" (Sept. 25th, 1907.)
representations have been made regarding the difficulties which

(32)

250 TARA RUBBER.

some brokers experience in advantageously 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 reasonably 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
Kuch consignments, from each estate, as one lot or accumulate small
lots until they have about 1 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 l.\ cwt. Up to the present time
man J' brokers have been able to dispose of their small lots in separate
batches, according to grades, but now that so many estates are
beginning 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 buj^ers. Each
small lot could be packed separately, according to quality, and
these placed in one box without any difficulty.

Messrs. Figgis and Son' are of the opinion that planters
might arrange to keep very small lots of the different descriptions
till they have at least 1 to 2 cwt. of one kind, as the large buyers
Avill not take very small lots. Should there be several small lots from
one estate they suggest that it may be wise to put them together
at the auctions so as to induce bidding. As a rule the larger lots
sell best.

Messrs. Lewis and Peat point out that they have had great
difficulty in advantageously disposing of small lots of plantation-
grown rubbers, both from Ceylon and the Straits. They allow that
it is only natural that shippers and importers should wish to sell
each grade separately and at full values, but contend that very
often these small lots only realize comparatively low prices, and
are not bought by the big buyers. They suggest that planters
should keep back the scrap, rejections, cut pieces and lumps, until
they have sufficient of each grade to till one case of, say, about
1 cwt. at least ; the finer qualities could be sent along as usual.

Messrs. Gow. Wilson and Stanton state that a difficulty has
been experienced in disposing of very small lots according to their
intrinsic value. They suggest that on estates at present producing
very small quantities, the manager sliould keep the rubber in
the factory until he has a minimum of, say, about I cwt. of each
grade ready for shipment. There should be little difficulty in
arranging this, and it would be of advantage to the producer.

PARA RUBBER. 251

This suggestion is not so necessary in the case of higher grades
of standard sheet, biscuits, etc., small cases of this can often be
satisfactorily disposed of to make up orders. With the lower
grades, however, the variation is much greater and the value less
certain, so that their disposal is more ditiicult.

Messrs. William Wright and Co. , (Liverpool) maintain that if
planters wish to realise the full value of their rubber, they will
continue to grade each parcel; each grade should, however, be
shipped separately. Buyers naturally will not trouble themselves
over small quantities ; the shippers should wait until they have a
reasonable quantity of each grade, and then ship each quality as
a separate consignment.

Messrs. Waterhouse and Sons (Liverpool) consider that in the
interests of planters and merchants the practice of shipping such
small lots is to be avoided, as better prices are invariably paid for
fairly good- sized parcels. Presuming it is necessary to keep the
grades separate, it would be well if the planters could arrange not
to ship anj' one grade until a suflfioiently laige quantity could be
produced — not less than 1 cwl.

Messrs. Jewesbury and Co. claim that a buyer of clean sheets
of biscuits may have no use for the inferior grades of scrap, and
buyers of the latter may have no use for the former ; consequently
if you compel a buyer to take all grades, he will do so only at a
price under the market average value. The difficulties, however,
to a large extent cease to exist if the planter or importer gives per-
mission to his brokers to sell either in pubHc sale or by private
contract, whichever they find the more advantageous. They learn
that many manufacturers are experimenting wdth plantation rubber
and are therefore glad to be able to procure small lots of given
grades, for which they have been and are willmg to pay full market
rates ; the probable increase in the near future of the number of
estates consigning small lots to this market will, according to Messrs.
Jewesbury and Co. be fully met by the regularly increasing number
of manufacturers wlio are enquiiinr for small lots for experimental
purposes. The classification of the grades, is in the opinion of
this firm, a distinct advantage.

One or two brokers do not see any very serious objection

ainst small lots, but the majority agree that it would be

advisable for the planters to keep back small lots of lower grade

rubber until they have at least 1 cwt.; this is a recommendation

which is, by one firm, only intended to apjily to the poorer

qualities. Representatives of Ceylon biokers have suggested that

they might be prepaied to buy up, in Colombo the small lots

fnm vaiicus estates, and ship fame as one let when the minimum

quantity had_ been purchased. The accompanying illustration

252

PARA RUBBER.

sliows tlie various kinds of plantation rubber as they are pre-
sented to buyers in the auction room on sale days.

Analyses of Plantation Rubber.

The following analyses of the different forms of rubber are tabu-
lated for reference, though a wide variation must be allowed in each
case. A general average composition cannot be given until more
analyses have been made : —

Ceylon

Cey]

ion

Straits

Crepe

Ceylon

Lace.*

Worms.

Pale

Darker]

£isnuits<

_,_ . _,—

, _^_ <

Sample.

A. B.

0/
/o

0/ 0/
/o /o

Moisture

.. 0-85

0-50 0-45

0-90

0-70

0-50

0-52

Ash

.. 0-14

012 0-30

0-20

0-27

0-30

Resin

.. 2-66

2-68 2-75

3-50

206

3-60

302

Proteids or

Nitro-

genous matter

.. 1-75

2-62 269

3-85

3-67

2-36

2-56

Caoutchouc

..94-60

94-08 93-81

91-55

93-37

93-27

93-60

100-00 100-00 10000 lCO-00 100 00 100-00 100-00

I am indebted to Mr. M. Kelway Bamber for the analyses
of biscuit, lace (A), and worm rubber, and to Mr. P. J. Burgess,
for the privilege of using the analv3e^ of crepe rubber from the Straits
by Herbert Ballantyne, F.I.C., F C S.

* By Ballantyne, in India-Rubber Journal.

<ffi«e^

■<3»g)^

CHAPTER XIX.
DISEASES OF PARA RUBBER TREES.

Diseases of plants grown on small areas — Epidemics over large acreages —
Checking disease by tree bolts— Forest oelts in Malaya— Advantages of
mixed products — Block Planting — Retention of native compounds
between estates— Illustration showing hardy characteristics of flovea
brasiliensis— Diseases of rubber plants— Burrs, twists, and fasciations
—Para rubber pests in Brazil and Java — Pests of nursery plants and
stumps — Mites, bees and wasps, beetles, crickets, cockchafers, Cerotina
species, Pestalozzia, grey blight — (Tlwosporhim — Leaf diseases of
Para rubber — Fungi, Hehnmthosporium, Periconia, CladoaiMvium,
Macrosporium, t'crcos/)0)'«— Preventive measures — Fruit diseases of
Para rul)ber— Fungi, Nectria and Phytophthora — Preventive measures —
Stem diseases of Para rubber — Fungi on old stems and green twigs-
Preventive measures — Die back — Bntrijodiplod'm — Corticum — A bark
fungus in the Straits — Insects, wood-borers, ants, and slugs — Preventive
measures — Termen Gcstroi and rubber exudations — Extermination of
white ants — Borer in Java— Horned termite — Root diseases of Para
rubber Fvingi in Straits and Ceylon — Fomes in the Straits — Poliiponis,
Helicohasidium, and Hipnenochacte — Insects, termites, cockchafers,
grubs — Preventive measures — A disease on prepared rubber —Probable
causes & preventive measvu'es — Analyses of black A: yellow tacky rubber
— Chemical analyses of tacky and sound rubber — ^Moulds on rubber.

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 lias
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 considerations 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 anytliing like an epidemic is noticeable.

254 PARA RUBBER.

Perhaps the occurrence in large numbers of the host plants in

widely sepaerated 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 Para rubber to the exclusion of other kinds of rubber is a

dangerous system," has probably much to recommend it. On

some large estates the Para trees are being grouped, and each

group is separated from its neighbour by a belt of forest or of

Castilloa elastica trees. Such a belt would prevent, to a certain

extent, the spread of disease, and one might be able to more easily

combat insect or fungus pests, as soon as tliey made their

appearance on the enclosed Para rubber trees.

PoEEST Protective Belts.
It has been conclusively proved, to the satisfaction of most
tropical entomologists and mycologists, that many of the 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
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.

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 for projiagating parasitic species ! It is essential that, in
order to check tlie spread of insect and fungus jiests, the 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 bet-
ween parallel groups of cacao trees. One plan which has been sug-
gested is to plant five or more lines of cacao, the lines to be 10 to
15 feet apart ; inteiplant these with Dadap shade trees, if necessary,
tiicn plant three or six lines of rubber, the lines to be 10 to 20
feet apart. The rubber trees in one line might be all of tlie same
species, but adjacent lines, might, if considered advisable, be com-
posed of different species, say Para, and Castilloa.

PARA RUBBER 265

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 ])lants they are apt to die or
degenerate, the belts thus serving as traps,

FoKEST 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
])rought forward by planters, and though one does not find much
to support this view it is admitted that the origin of parasites in
the tropics is sometimes very problematical. Everyone, however,
with tropical experience is convinced tliat small properties are
generally freer from pests than large ones, and that barriers in the
form of belts of unlike species 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 very large tracks of forest of enormous width are
retained between certain districts. In his annual Report for 190(),
Carruthers states :

" The value of protective forest belts' was'explained in the
last report and these necessary guards against plant diseases are still
occupying my attention, and Government will be asked to continue
the policy and reserve more of these belts to cut off various planting
districts from each other. Dr. Treub of Java, who is the greatest
living authority on tropical agriculture, is much interested in these
protective jungle belts ; he considers them a sound and wise pro-
vision which unfortunately in Java and other agricultural countries
it is now too late to lay out as too much land^has already passed
away from the control of the State." "*"

Tliis is a system which the Government Mycologist at
Peradeniya approved in September last when he stated as follows: —
' • I should like to express my entire agreement with the suggestion
that the Hevea acreage should be broken up into small blocks by
belts of other trees. The reservation of forest belts in the F.M.S. is
one of the most important advances in disease that have ever been
made. There is, unfortunately, no similar policy in Ceylon.''

Advantages of Mixed Peoducts.

Mr. Green, the Government Entomologist on the same
occasion, stated 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 sj^stemof 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

^56 PARA RUBBER

are intimately mingled together — are not nearly so subject to the
ravages of disease. Apart from the physiological benefits of com-
mensalism — now becoming more generally recognised — the more
or less complete isolation of individual species that occurs under
natural conditions is itself a 3 heck to the extension of disease."

"These facts lead up to the consideration of what Hook upon
as by far the most important part of my subject, that of isolation.
During the six years in which I have occupied my present position,
and the many previous years of practical experience as a planter,
I have been impressed with a sense of 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. The task has seemed a hopeless
one, and has too often proved an impossible one. What are the
conditions that prevailed during the reign of colfee 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 liindrance 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 limited area; but the
disinfected parts are immediately liable to Iresh invasions from all
sides. Given an isolated field we can deal with a pest with some
confidence that our labour will not be nullified. I would most
earnestly urge our rubber planters to take warning from the mis-
takes that have been made in the cultivation of the older staple
products of Ceylon."

"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 fohage. As in most trees the lower parts are bare
of foliage, a separate undergrowth will be necessary to easure 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
means. Insects, though seldom dependent upon a single species
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, their is much less chance of the inter-communi-
(•ation of pests. It is not in my province to decide what particular
species should be employed for the purpose. That is a matter
that nmst be determined by the botanists, and will be affected by
considerations of climate and altitude. The anticipated profits
from a single rubber tree are so great that proprietors are tempted
to plant up every available spot and are unwilling to allow a single

PARA RUBhEH. 257

yard of suitable soil to be occupied by what they would consider
to he un]>rofitable growtlis. This is surely a very short-8i^':hted
2)olicy ; but to meet their view I would suggest that screens
composed of other species of rubber — for example — Rambong and
Castilloa — might be interposed between adjacent fields of J^ira
rubber. Both Rambong (Ficus elastica) and Castilloa are members
of the family Urticaceae, while Hevea l)elongs to the distinct
family Euphorbiaceae. We do not, at present, know very miu4i
about the productiveness of these two kinds of rubber in Ceylon,
but any yield that they may possibly give should be looked upon
as pre-requisite, their true value being as a means of insulation to
the more valuable Hevea plants. I may mention that the Ceara
rubber is a close lelative of the Hevea, and is consequently
unsuitable as a component in the protective screens. As an
undergrowth — in conbination with Rambong and Castilloa — tea
and coffee might be tried, or some plant the clippings of which
might be employed as green manure. Cinnamon would make an
almost ideal screen as undergrowth."

Block Planting.

It is not necessar}' to apologise foi- 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 oflicials
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 unlike
species. This blo?k 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 dist ict 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 mvestigate the life histories of 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 as soon as they appear. The
first appearance of a pest in the tropics is usually promptly notified
by the authorities, every publicity is given to even the harmless
forms, and planters and investors are now fully alive to the impor-
tance of carrying out well-advised plant sanitation operations.

(33)

258 Px\RA RUBBER.

The conditions under which ruhber plants are sometimes grown
appear to be favourable to the spread of diseases, but it is satisfactoi">'
to know that effective remedial measures can be applied a^ainsl
most of the pests known to affect cultivated rubber plants.

It is, however, well to realize that trees of Para rubber, whethei-
ji;rowing under unhealthy or perfect conditions, are not immune
froju the attacks of parasitic fungi and insects, even at a time when
tlie number and age of the host plants may seem to be almost neg-
ligible. The best advice which (;an be given is to attack all diseases
in their earliest stages before the parasites have ijicreased beyond easy
control. It is fortunate that among the many diseases or peats
mentioned below most of them are not of a very serious nature,
but they are nevertheless worthy of full consideration. Only the
more important pests ai-e dealt with in these notes.

Burrs, Twists, and Fasciations.
Unusual growths which cannot be associated with any pests
often ap])ear on healthy Paia rubber trees.

Sometimes the trees are irregulai- in outline in consequence
of h living becMi exposed to wind, the surface facing the wind
frequently being flattened; such trees when twi.-?ted are not as
easy to tap as those with normal stems.

Burrs or rounded woody knots are frequently observed
projecting fiom the bark, each fitting into a depression ; they occur
on many of the Henaratgoda trees which were, many years ago,
tapped on the V system. These burrs, though they make tapping
operations dilificult, do not seriously affect the vitality of the tee:
they are sometimes associated with bad tapping or bruises but
are also often derived from dormant buds.

Fasciated stems have also been recorded but these do not
appear to be due to parasitic fungi oi" insects

Para Rubber Pests in Brazil and Java.
Mannings* has described and iigured fiv^e leaf fungi, viz.,
Phjdlachora Hubcri, Dothidella Ulei, Aposphaeria Ulei , Ophiobok)S
Heve», and Parodiella Melioloides. These have been found in
Brazil, but do not seem to be very .serious, though the Ophiobolos is
said t(> destroy the leaf and is perhaps the most dangerous of them.

On sick and rotten trees of various species of Hevea, Allesche-
riella uredinoides was found.

In Java, Zimmenuann has recorded in the Bull. Inst.,
Buitenzorg, several fungi on Para rubber. Phyllosticta Heveae,
Zimm., is a fungus causing brown spots especially at the tips of

* Notizblatt des Konigl. Botanische Gartens und Museums zu Berlin
iVol. 4, No. 34, p. 133).

Lent by ALiclaroi & Sons.
FASCIATION OF PARA RUBBER TREE STEM-

PARA RUBBER. 259

the loaves; GlaiosporiuDi elasticiic, Cookt^ and Alass., is aiiotlier
leaf fungus which produces hght greenish spots and masses of
reddish spore

Nursery Plants and Stumps.

Iih^cct Pests. — "Mites" in rubber nurseries have also been reported
from tiie Straits.* Arden states 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 j)unctures. He
compares it to '" Red Spider," and believes that tlie disease is mainly
limited to plants growing under unfavourable conditions.

Mr 10. E. Green lias liie following notes regarding pests whi(;h
are associated with the stems, in the Tropica! Agricul rist,
February, 1906 : —

"The cut ends of young Hevea stumps are frequently
tunnelled by various small species of bees and wa^^ps. 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 Hevea plant is stumped it usually dies back to th(5
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 plant. SpecimetLS of a small Longicorn beetle, said
to be responsible for tiie death of young Hevea rees, have been
received from Southern India. The insect proves to be Pterolophia
annu'ata, Chevr., a species that occurs in Ceylon also. I have no
records of injury done by this insect to Para rubber in this country,
but I have bred out a specimen from the diseased bark of a Ceara
rubber tree. ^\y 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 manceuvre is believed to be to
check the sap and induce the degree of decay best suited to the
nourishment of the grubs of the beetle ; the eggs having first been
inserted in the back above the j)oint of injury. If this pest should
become common, it might cause serious damage on rubber plant-
ations. In case of any occurrence of the pest the stems of ail
the trees should be carefully searched. The adult beetles will
probably be found clinging to the bark of the trees, when thej-
can be easily captured and destroyed."

Crickets have been described as biting oil" the tips of rubber
seedlings, by Ridley (Agr. Bull. No. 3., March, 1906) and

Stanley Ardeu, Agr. Bull, of the Straits and F.M.S., June, 1905.

■260 PARA EUBBER.

Waterliouse of .the British Museum has identified some of these
pests as Brachytrypes achatina and Gymmogryllus elegans.

The grub of the large Cockchafer (Lepidiota pinguis) appears
to be troublesome on young Para rubber plants ; Green
reports over 3,000 plants being killed in a single clearing.
In some cases the tap root has been eaten right through. If the
soil is dusted with Kainit, Nitrate of Soda and "Vaporite" the
grubs can sometimes be kept in check.

Green, in a recent issue of the "Tropical Agriculturist",
reported upon a small bee, found in the centre of stumped Para
seed ings. The bee was a species of Ceratina, the tribe usually
making their nests in the pith of dead branches ; if the stumps
are cut back to a point just above a node in the stem the bee
will probably not be able to build its nest in the pith. Green
states that the following species have been observed to infest
young rubber plants : — Trypoxylon intrudens and T. pileatum
(provisioning their nests with spiders), Stigmus niger (with
Aphides), Odynurus sichelii (with small caterpillars), Ceratina
simillima, C. viridissima, and C. propinque (with bee-breed).

Sioecimens of a Longicorn beetle (Moechotypa verrucicoUis,
Gahan.), said to have killed young rubber stumps, have been
reported upon by Green (T. A. August, 1906).

The bark of the plants had been nibbled off, and the bare
wood exposed. Examination of the roots proved that they had
previously been attacked by the parasitic fungus, Botryodi-
plodia elastica', Petch. Green further states that this fungus
attacks the collar of the plant ; kills the upper parts by cutting
olf tlu^ supply of nourishment ; and may work down into the root.

Fungus pests a species of Pestalozzia — identical with that which
is associated with the "grey Blight" on tea leaves — has also been
found by Petch on leaves of nursery seedings of Hevea, and according
to that mycologist were probably infected by wind-blown spores from
the adjacent tea. The fungus produces white irregular areas spreading
generally from the tip of the leaf. In the Straits* the leaves of the
Para rubber seedlings have been attacked by a fungus, regarcling
which Mr. ^Massee reported: " The pale blotclies on the leaves are
caused by some species of Cercospora, but the absence of fruit pro-
vents specifics id«Mitification." Ridley states that this leaf fungus
is common all over the Malay Peninsula, but that except in the case
of seedlings does not do much harm.

Potcli has recently found a species of Glooosporium on 1 lie Icave^^
'if seedlings ; the fuii;,'us foiins light brown spots on the u[»per sur
face of the leaves, and tinaliy the latter turn yellow and fall.

+ Agriculturist Bull, of the Straits and F.M.fc)., July, 1905.

PARA RUBBER. 261

Grey blight on the stems ofseeclHiigs lias also been observed by
Peteh. The fungus forms a white zone about an inch long just
above the surface of the ground. The stems lose their pith,
become hollow, and the plants die.

Leaf Diseases.
There are already several insects and fungi whicli live on the
leaves of the Para rubber trees, but none of them are very harmful.
To a very limited extent the annual fall of leaf that takes place on all
Para i ubber trees after they have passed their second or 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 luippen
to fall prior to the formation of the spore-producing bodies, and iji
this way assist, to some extent, in checking the spread of disease.
But it should be remembered that the Para rubber trees are in pos-
session of tlieir fohage for about 50 out of every 52 weeks each year,
and to assume that the leaves, owing to their deciduous character, are
not likely to contract a permanent disease is by no means sound.

Fungi. — Leaves of Para rubber seedlings and of older plants
have been attacked by aspecies of Helminthosporium ;* the leaved
were " studded with circular, semi-transparent spots, eacli surround-
ed by a brown cushion from which arose the threads of the fungus."
It was suggested that the spots were due to punctures by insects and
the fungus grew on the dead tissue. Damaged parts of the leaves
of Para seedlings are also subject to the attacks of Periconia
pycnospora,t and species of Cladosporium and Macrosporium.

It is satisfactory to know that, up to the present time, the
leaves of mature Para rubber trees are jjraetically free from i:)arasitic
fungi, but the disease on the leaves of seedlings is one which leads to
partial defohation and checks tlie growth of the young plants. In
all such cases the diseased leaves should be pulled oft' and burnt and
the rest of the plants spraye with Bordeaux mixture ; this
consists of 6 lb. of copper suljDliate and 4 lb. of freshly- slaked burnt
lime in 45 to 50 gallons of water.

Insects. — According to Green j the leaves of Heveaare reported
to have been punctured by certain plant-sucking bugs, the most hkely
species being Leptocorisa acuta and Kij)tortus linearis ; the former i3
known as the "Rice-sapper." It appears that these pests puncture
the leaves and stems. "The injured loaves show uutncrous small
spots, each bordered by an irregular dark riju, within which the
tissues have dried and turned white." It is beheved that the injury
to the leaves is due more to a fungus than to an insect.

» T. retch, Mycological Xotes, Tropical Agricultm-ist, June, 19Uj.
jE. E. Green, Entoraalogical Notes, Tropical Agriculturist, April
and May, lOOj.

202 PARA RUBBER.

A scale bug — Lecaniuni iiigruni, Nietii. — lias also been observed
by Green on the leaves of young Para trees, but this can be easily
destroyed by means of Macdougal's mixture. The tips of seedUngs
occasionally turn black and dry up, and it has been suggested that
this may be due to some plant-sucking bug. A species of weevil,
allied to if not identical with Astycus lateralis, has been known to
eat the leaves of Para rubber in the Straits,* and the only remedy
is to collect and destroy the weevils.

Green has also recorded in the T. A. and Mag. C. A. S., Decem-
ber, 1905, a new species of scale bug (Coccid) upon the leaves,
belonging to the genus Mj^tilaspis, but he considers tliat it is un-
likely to cause any serious ti'ouble.

(Spotted locusts have also been te|)()rted to fl(» considerable
damage to the young rubber plants in Ceylon and the Straits.

Locusts have been reported from various districts in Ceylon, and
are said to destroy the seedlings and also the leaves of mature
plants. According to Green (Tropical Agriculturist, November,
1905) poisoned baits have been found effective in such cases, one of
the best being "Arsenic salt horsedung " mixture, made by com-
pounding one part of Paris green or white arsenic with two parts
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.

Fruit Disease.

Para rubber 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 cxpelUng the seeds. The fall of the unexploded fruits
is often due to Aviiid, and there is no ])arasitic fungus to be found
in the tissues. It has been stated that the fruits are subject to
the attack oi a parasitic fungus belonging to the genus Nectria, and
( arrut liers;|: ie])orts having successfully inoculated Fara rubber fruits
with this fungus, but was not certain as to whether it. attacked the
fruits when on tlie tree or only when tliey fell to the ground. Fetch§
siil)se(|nently stated that the disease on Para niblier finits is chic to
n parasitic fungus similar to, if not identical with, that which causes
the dct^ay of cacao pods. All tjie Hevea fruits examined arc
att acked by a species of I'hytophthora , which peinu^ates the soft outer
tissues of the fruits ; the seeds dry up later when the supply of food
and water is cut off. In addition to the ordinary spores which infect

* Wray, t'erak Museum Not^s, 1897.

r J. B. Carruthcrs, Ciix-ular K.B.G., Poradcuiya, January, PJOu.

§ T. I'ctch, Mycological Notes, Tropical Agriculturist, 1903.

PARA RUBBER. . i»«i;{

other fruit wliile the origmal fungus is flourishing, restuig spores are
formed in the dead fruit. These are liberated when tlie fruit deeays,
and thus seive as a source of infection to the following crop. In
this waj' the fungus bridges the gap between the crops

The most effective way of fighting the fruit disease is to collect
all dried fiuits which are on the trees and those which have fallen
to (he ground and buru the lot on tlie spot. On the average rubber
estate theie lan be no real objection to burning such sinall ((uantities
of fi'uits as this treatment involves.

Stem Dlseases.

Fwufi. — In his account of canker (Nectria) of Para rubber Car-
ruthers points out that a parasitic fungus occurs on the stems and
branches, which may prove fatal to the trees. The area attacked b\-
the ftuigus can be detected often by thecliange in colour of the baik
or by the exudation of the latex. When, however, the funijus
has got a lirni liold of any local patch of tissue, the latex tubes l)c-
come quite empty and dry up, so that it not only threatens (he lite,
of the tree, but also robs the planter of the latex or rubber for which
the tiee is being cultivated. It is necessary that all cankered areas
should be excised and the tissue burnt on the spot. All the dis-
coloured areas should be removed, even if the woody tissues below
the cambium are permanenth' damaged in the opei'ation. In some
ca.ses it is true that the cankered area is. by means of a layer of cork,
prevented from extending to other jiarts of the stem, but it is unwise
to leave the matter to chance.

The disease mentioned above has been found by Carrutheis on
" almost all parts of the tree except the young branches and the
roots," but even the.se ]mrts have now been shown to be attacked
by other fungi.

Petch* has observed a bWkening of green stems of Para rubber
trees to be due to a fungus which produces a network of dark-
coloured threads on the exterior.

Tke "die-back,"* accoiding to Petch (Annual Re])ort. 19(>()).
continues to kill off trees aboiit a year old. " The stem, usnallv
near the top, turns brown, and ultinu'.tely dries up. If tlie
diseased pa;t is allowed to remain, this condition travels down to
the base and kills off the tree altogetlier. The affected part
should b^ cut off and burned. The fungus on the diseased area is
Glo-eosporium alborubrum, Petch.'

In his Annual Report for 190ti, Petch states that young plants
have often failed to grow after being planted out. '-'in all ca.se.s
Botryodiplodia elastica, Petch, was found to have attacked the

* T. Petch, Mycological Xotes, Tropical Agriculturist, August, 1905

204 PARA RUBBER.

plant at tlie collar, and the same fungus was found on stumps
wliKih died under similar conditions in Burma. It probably enters
the stem through injuries made during planting. Where it occurs
basket plants should be used, or seed planted at stake." He also
]>oints out that there seemed some probability that this fungus
was identical with Diplodia cacaoicola, Henn., which is parasitic
or saprophytic on cacao, but on this matter no definite opinion
can J)e given.

A bark fungus has been described in the Straits Agricultural
Bulletin,* November, 1905: — " This fungus takes the form of a
pinkish- white mass, coating the bark irregularly so as to have an
appearance often of hieroglyphics. Attacking usually the upper
branches or occasionally the stem, it quite destroys the bark and
causes the death of the wood beneath. Fortunately it is easy to see
from its conspicuous whitish colour, and easily dealt with by destroy-
ing infected branches, and in the case of the trunk being aifected by
scraping it oft" and treating with copper sulphate and lime."

This is apparently the omnivorous fungus previously recoi'ded
from Java by Ch. Bernard (Teysmannia " 5, 19 and named
Corticium Javanicum, Zimm). It destroys the bark, killing small
branches and causing " canker" on the larger. It has also been
recorded in Ceylon and South India.

Insect pests. — Ridley has reported the existence of a borer which
may attack the wood of Para trees, and identified it as belonging
to the genus Platypus,

Antsf attack the incised areas six feet from the ground, and in
some cases construct earthworks up to a height of 30 to 40 feet and
enter the tree at some weak point or wound area. The white ant —
Termes gestroi — is reported to be one of the most troublesome pests
in the Federated Malay States. Arden, when dealing with the loss
of Para rubber trees in the Straits, points out that there may be
some association between the ravages of the white ants and the
fungus of the roots of Para rubber. Similar relationships have been
suspected in Ceylon, J where the taproot had probably been eaten
by white ants and the dead roots were covered with a network of
white fungus hypha?. "The fungus attacked the sound wood and
bark, and that the injury was due to this was sujiported by the
receipt from another locality of a young plant which had been killed
by apparently the same fungus. In this case there were no side
roots ; the plant therefore died after the taproot had been per-
meated by the fungus, and as this was indicated by the withering
of its leaves, it was uprooted before the white ants discovered it."

• Straits Agriculturnl Bulletin, November, 1905.

•j- Stanley Arden, Ajmual Report, 1902.

:}: T. Patch, Mycological Notes, Tropical Agriculturist, October, 1905

PARA RUBBER. 265

Termes Gestroi and Rubber Exudations.

Para rubber trees in Borneo, Strait Settlenieiits, and India also
suffer from the attacks of Ternies GfCstroi. The termite appears to
be quite as destructive when the rubber trees are growing on grass
land, or among 'ialang" as on clear weeded properties. The insect
mainly works its destruction in the dark and gradually hollows out
the trunk of the tree, the branches begin to die and the tree is us-
ually blown over during windy weather.

Stebbuig * has published an interesting accomit of the termite
pest in India and two species of the Termitidae, T. Gestroi and
T. Annamensis, desn., have been shown to be associated with trees
of Hevea brasiliensis. A fanciful and erroneous idea has obtained
a footing that Termes Gtestroi ' ' attacks the tree for the purpose of
obtaimng rubber from it, for, on applying pressure to the bodies of
the termites, it was fomid 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 m 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 j & Green J
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.

Extermination of White Ants.

Planters and officials have made repeated attempts to eradicate
Termites ("white ants") and though carbon bisulphide is a most
effective means of destroying the insects in situ in theii' subterranean
nest it has not yet been largely used. The extended api^lication of
this treatment has been handicapped by the impossibility of ob-
taining a sufficient quantity of the fluid at a reasonable cost. The
suggestion that carbon bisulphide might be manufactured in the
tropics has nowbeen taken up and Green (Annual Report, R. B. G.,
Ceylon, 1906) announces that "In the meantime what promises
to be a still more convenient and equally effective fumigating
apparatus has been perfected and has been in use in South
Africa. I have obtained one of these machines and am now
conducting experiments, which lead me to believe that a really
satisfactory means of exterminatmg white ants is now at our dis-
posal. The treatment consists in the volatilization of a mixture
of sulphur and arsenic. The deadly fumes are driven by a power-
ful air pump into the galleries of the nest, permeating every part

* E. P. Stebbiug, Indian Forestor, Vol. XXXU, 19U6.

t H. N. Kidley, Agr. Bull, of tho iStraits and F. M. S., April, 19U(j,

X E.E Greeu, T. A. & Mag. C, A. S.

(34)

266 PARA RUBBER.

of it, as evidenced by the issue of jets of smoke from uiiHUspected
apertures for several yards round the main shaft. Tlie apparatus
is small, light and comijaratively inexpensive, being placed on
the market in South Africa at the price of £4 sterling."

Ridley reports an attempt to drive the termites away by
filling tlie holes witli cement, which though successful in tlie in-
stance referred to, does not appear to have been repeated.

Ilevca hnmlienuls has been attacked by a borer in Java,* the
report being to tiie 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 Scolytidoe.

Green also records ^T. A. August, 1906) a cas3 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, but does not apparently
feed upon the wood itself." Though the termites occupied a large
cavity in the bole of the stem, the tree continued to live.

Green states that he has repeatedly received specimens of dead
brandies and stems oh' Hevea hrasiliensis , perforated by a Bostrichid
beetle (Xylopertha mutilata, Wek.), but he believes that in every
case the be.tle has effected its entrance after the death of the parts.

SlugsJ (Limax sps.) have also been reported as attacking the stem
and eating th? remains of the latex left in the wounds after tapping.
" Living specimens of tlie slugs received at Peradeniya were fed with
fresh latex. . Its presence was almost immediately scented ou by
them. One Ol them drank for about ten minutes." Hand-picking
or the use of quick-lim3 should be effective.

Root Diseases.

Fungi, — A root disease due to a fungus has already been men-
tioned as occurring in the Straits and Ceylon in association with white
ants, but probably preceding them. Petch has shown that the
Ceylon fungus can spread underground on roots of grasses, &c., and
that it is a species of Polyporus (Fomes semitostus, Berk). The
hyphic are described as occurring on the first six inches of the trunks
as well as the roots. Any trees so affected should be isolated by
digging a deep trench round them about a foot wide, as in the case
of the root disease in tea, and, if possible, the diseased specimens
should be uprooted and burnt.

* Bulletin du department de I' Agriculture aux Indes Neerlandaises,
VI, p. 4b.

:;E. E. Greeiii Tx*opical Agriculturiat. Sept., 19U.'>.

< s u.

tc
o

-/ o

r- «

2 w

-, J) o
UJ S5

a: < >

PARA RUBBRR. 267

The Fomes fungus, affecting the roots of rubber plants in the
Straits, is described as follows in the Agricultural Bulletin of the
Straits and F. M. S. for May, 1004 :—

' ' 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.

" This fungus is verycommon on decaying stumps of all kinds
of trees and is, properly speaking, a dead wood feeder, but like a
number of allied species attacks also living trees.

"As a disease fungus I would class tliis as contagious, as opposed
to an infectious fungus, as it appears to spread from root to root in
the ground without being dangerously dispersed through its spores.
A dead stump may be attacked above or just below the ground, and
the mycelium spreading along the decaying roots may come into
contact with those of a living tree, and so the attack is spread.
These contagious fungi are more easy to deal with than the infec-
tious ones of wliich the spores are blown from tree to tree and
attack the plant where they alight (as in the fungus previously de-
scribed). The infected trees should be destroyed and the roots dug
out, every bit of dead root or decayed timber being removed and
the ground well saturated with copper sulphate and lime.

'■Tubeuf, in writing of a similar parasite in Europe (Fomes an-
nosus) whose habits are very similar to those of F. semitostus, states
that the best way of combating the ravages of the parasite is isolation
of infected areas. These should be isolated by ditches with vertical
sides deep enough to cut through all roots, care being taken to leave
no diseased stems or roots outside the circle. After remaininor
open for a time the ditch must be filled again with soil to prevent
the formation of sporophores on the exposed roots. All diseased
stems should be felled and burnt, or deeply covered with soil to pre-
vent the formation of sporophores; in fact, isolation of these
contagious parasites should be done by ditches in the same way as the
infectious parasites are isolated by screens of trees of another
species."

In the opinion of Mr. H. N. Ridley, Director, Botanic Gardens,
Singapore, tliis is one of the most important diseases in the Straits
on Para rubbei', and deserves prompt attention.

As Messrs. Ridley and Derry have pointed out, this fungus, the
mycelium of which is underground, is the worst feature against
close planting, as under such conditions it might spread very rapidly.

268 PARA RUBBER.

The uprooting of all dead stumps of trees would appear to be
necessary if this disease is to be kept in check. The removal of
the jungle stumps would be very effective, if it were economically
possible.

A fungus (Helicobasidium sps.) has been found attacking the
roots of Para rubber in the Straits.* This fungus usually spreads
rapidly from tree to tree by means of strands of mycelium;
trenching and liming are generally recommended as preventive
measures.

Another root disease has been found in Ceylon by Petch.f
This one has also been found on cacao, tea, and Caravonica cotton in
Ceylon, but is not very dangerous. " The roots are covered with
a thick yellowish-brown felt which sometimes develops a black crust
exteriorly. Stone, sand, &c., are firmly attached to this covering,
and give the appearance of pudding-stone." It is believed to be a
species of Hymenochgete.

Ridley J has recorded the occurrence of a subterraneous fungus on
the roots of Para rubber trees in Borneo and Perak. The fungus
exists as a white mycelium on the roots of the trees under two years
old, and spreads to the base of the stem. The behaviour of the
fungus suggests a similarity to that of Fomes semitostus and in the
opinion of Ridley may be one of the Polyporese. Ridley recommends
that the soil should be limed and rubber trees should not be plant-
ed on the affected area, but plants of the Banana may, perhaps,
be grown in order that the decomposed and infected wood and
roots in the soil may be broken up; trap crops might, perhaps, be
useful under such circumstances.

' The "brown root" disease, which attacks cacao, castilloa, Hevea
etc., seldom kills out more than one plant, though it attacks prac-
tically everything according to Petcli (Annual Report 1906.) It (!an
be distinguished by the thick coating of sand and stones which
adheres to the mycelium on the root. "It appears to be indentical
with the mycelium attributed to Hymenociioete in Samoa and to
Sporotrichum in Java ; it is probably the same as the Irpex flavus
of coffee. Hevea is more often attacked when planted amongst
cacao, or in old, cleared cacao land."

Petch advises that the trees, thus affected, should be removed
as soon as they are dead.

Insect Pests. — "Specimens of Termites§ {T. redemanni) have been
sent with the report that they were eating off the tap roots of young

* Johnson, 1. c. p. 29.

t T. Petcli, Mycological Notes, Tropical Agriculturist, October, 1905.

X Agr. Bull., No, .3, March, 1906.

§ E.E. Green, Entomological Notes, Tropical Agriculturist, April, 1905.

PARA RUBBER. 269

rubber plants. A mixture of lime and suli)luir, forked into the soil
immediatelj' jound the plants, has been found effective in prev^enting
the attacks of white ants. The proportions are one part po\vdere(l
sulphur to four parts of lime. In replanting, the holes should be
filled with earth mixed with lime and sulphur in the proportion of
one basket of sulphur, four of lime, and seven of soil. This should
protect the new plants from any underground attacks.

Grubs of the large cockchafer {Lepidiota pinguis, Burm.) have
been received by Green* 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 working is by seeing
the green shoot on the stump die back. On touching the stump it
breaks off. Specimens of injured stump (of about the thickness of a
lead pencil) were sent in with the grubs. 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 kainitand 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 same species was recorded in 1902 from the
Negombo District, where it attacked the roots of cinnamon
bushes. The adult beetle is of considerable size, being fully an inch
long and proportionately stout. The larva is a white fleshy grub,
tw^o 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."

" A formidable looking grub of some large beetle (Buprestid or
Longicorn'^) has been sent by a correspondent from Ruanwella. It
is said to have been found in the taproot of a rubber tree tliat had
died and broken off. The pest in its larval stage, working — as
it does — below ground-level, will be difficult to attack."

A Disease on Rubber.
It seems as though enough has been said regarding the troubles of
all parts of the plants with fungi and insects, but tiiis note deals with
a disease on the prepared rubber and cannot be omitted. The signs
of the disease are that the rubber becomes at first sticky or tacky,
and rapidly softens until it is almost liquid. It can be spread from
one biscuit to another by contact. It is supposed to be due to
bacteria, which first commence to grow on the sugary and gummy
substances in imperfectly washed rubber and ultimately on the
decomposing protein or albuminous material previously referred to.
It can to a great extent be kept in check by well washing and squeezing
the freshly-coagulated rubber, rapid drying without exposure to

* E. E. Green, Entomological Notes, Tropical Agriculturist, October,
1905.

270

PARA RUBBER.

higli temperatures, and the use of formalin in the latex and on the pre-
pared rubber. Mr. Kelway Bamber recommended that the biscuits
be wiped with a solution of formalin, diluted to make a 2 per cent,
solution, and not be allowed to touch one another earlier than
necessary.

The following are analyses of two samples of tacky rubber
by Mr. M. ICelway Bamber : —

Analysis of Black and Yellow Tacky Rubber.

Black. Yellow.

Moisture . .
Resin

Proteins . .
Ash
Caoutchouc

per cent.

0-64
4-00
2-19
2-02
91-15

100-00

Nitrogen . . . . 0*34

Resin by Alcoholic ex-
traction .. 0-68

per cent.

0-64
3-02
2-19
1-26
92-89

100-00

0-34

0-72

The first rubber obtained from old trees or that from young
trees seems very liable to undergo putrefactive changes. It has been
suggested that these decomposition processes may be due to niole-
cular changes of one or more of the constituents of prepared i-ubber,
in which case it would be very difficult to adopt measures to prevent
the undesirable result. It has also been pointed out that the pre-
.sence of large quantities of oily and resinous substances having a low
melting point may be the cause of much liquefaction and subsequent
decomposition. The chemical analyses of rubber showing varying
degrees of tackiness have already been given. They appear to in-
dicate some relationship between tiie high percentage of resins and
proteins and the degree of stickiness and liquefaction. For the sake
of comparison the analyses of sound and very tacky rubber are here
reproduced : —

Moisture

Ash

Resin

Proteins

Rubber

Sound Rubber,
per cent.

0-30
0-,38
2-36
3 • m
93-40

Very tacky Rubber,
per cent.

0-44
0-72
3-70
4-90
90-24

100 00

100-00

PARA RUBBER. 271

The development of bacteria, which has been shown to be asso-
ciated with putrefactive changes of rubber, might, however, bo
overcome either by inoculation, effective drying, or the use of
antiseptics.

Moulds on Rubber.

An examination of the rubbers from various cotuitrics was
carried out by Fetch, (Annual Report, 1906) in order to determine
their comparative resistance to moulds. The mould which {jrows
on prepared rubber in Ceylon is apparently Eurotium candidum
Spcg.

CHAPTER XX.
WHAT TO DO WITH THE SEEDS.

Number of seeds per tree — Seed characteristics — Value — Seed oil and
fat — Meal and cake — Analysis of meal — Cake of Para rubber seed
compared with linseed and cotton cake — Packing Para seeds for
transport — Experiments at Trinidad and Singapore — Charcoal,
sawdust, and Wardian cases. — Ridley against Wardian cas^s.

IT is well-known that trees of Hevea brasiliensis flower and fruit
after their fifth year in Ceylon. In other countries plants
raised from cuttings have been known to produce fruits within three
years. Each fruit usually contains three seeds, and the number
of seeds annually produced per tree is about five hundred when the
trees are mature.

The following interesting information was published in the
"Times of Ceylon" regarding the number of seeds produced from
a five-year-old tree and its offspring, assuming that each tree after
attaining its fifth year produces 500 seeds annually : — •

'Year.

1st

2nd

3rd

4th

6th

8th

10th

Total Seeds at end

Year

of each year.

501

nth

1,001

13th

1,501

15th

2,001

17th

253,001

18tli

1,504,001

19th

3,755,001

20th

Total Seeds at end
i. of each year

130,255,501

1,259,006,501

4,388,757,501

323,019,508,501

952,522,759,001

2,208,151,259,501

4,402,530,010,001

The 500 old trees at Henaratgoda and Peradeniya produce annu-
ally about 200,000 seeds, equal to approximately one ton by weight.
At the present time tliere are about 150,000 acres of Para rubber
trees in Ceylon, 100,001) acres in Malaya, and very large areas
in other parts of the world. It is, therefore, necessary to study
the properties of tlie seeds in the event of more being produced
than are required for planting purposes. It is obvious from a
glance at the above table that, before long, very large quantities
of seeds will be available.

I visited several estates in the East durmg 1908, where the
seed supply was wasted ; the price paid for seed for planting pur-
poses did not permit of a profit being made.

The seeds of Para rubber contain an oil which has been valued
at £20 per ton, and also yield a cake which may be valued at £5 to

PARA RUBBER.

273

£6 per ton. The decorticated seeds have been valued at £10 to
£12 per ton, and brokers in Europe consider that it would be more
profitable to ship the seeds from the Tropics to Europe.*

Para Rubber Seed Oil and Fat.

" The kernels constitute about 50 per cent, by weight of the
whole seeds, and yield 42-.'] per cent, of oil. Tlie 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."*

Para Rubber Seed Meal and Cake-

Old ground seed so finely divided as to form a meal was re-
ported upon by the Imperial Institute as follows ;-

Chemical Analysis.

Moisture

Asli

Fibre

The ash was found to contain 30-3 per cent, of phosphoric acid
present in tiie form of phosphates, which is equivalent to 1-07 per
cent, of phosphoric acid in tlie 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 expressed
from the decorticated seeds, the residual cake could be utilised
as a feeding material, as is shown by the following comparison
between the calculated composition of such a cake and tlie com
positions of some commerical feeding cakes."

jaer cent.

per cent

Oil

.. 36-1

3-53

Proteins . .

.. 18-2

3-4

Carbohydrates

.. 29-G7

Calculated

Linseed Cake.

Composition

, ^^ » Cotton Seed

of Para rubber

New Old

Cake.

eed Cako.

Process. Process. New process.

per cent.

per cent. per cent.

per cent

Moisture

13 •3()

9-4 .. 10-8

. Ill

A.sh

■ 5-10

5-4 .. 50

6-1

Proteins

26-81

. 35-6 .. 28-6

38-47

Fibre

5-00

71 .. 6-7

9-78

Fat

n-00

7-5 .. 10-6

8-78

Carlmliydrates

43 • 64

. 350 .. 38-3

25-75

Nutrient vaUie

84-2.-)

. 87-85 .. 91-28 .

84-4

A Report by the Director, Imperial Institute.London.

(35)

274 PARA RUBBER.

" These figures show that a oake prepared from Para rubber
seed meal may form a good cattle food, and tliat it contains very
httle indigestible matter."

There is, therefore, in Para rubber seeds an economic product
which may soon become important commercially ; if the oil is
expressed from the kernels before the meal or cake is made, the
residue may be used in the Tropics either as cattle food or manure.

PACKnTG Seeds for Transport.

The difficulty of transmitting seeds of Hevea brasiliensis to
distant countries is well-known ; the seeds do not retain their germin-
ating capacity for a very long time except great care is taken
in collecting and packing operations.

Twenty seeds were sent from Singapore on February 12 to
Mexico, where they arrived on May 2 in the same year ; fro.i
these fourteen plants were raised.

Seeds of Para rubber, after being dried in the sun for a short
time, packed in dry earth, and sent from Penang and Ceylon to
.India, have arrived in the latter place with only 17 and 31 per cent.
of loss due to the seeds going bad. They have also been success-
fully sent in burnt ricedust or powdered charcoal in hermetically
sealed boxes or tins over very long distances. From 30,000 seeds
packed with charcoal and sawdust in ordinary cases, sent from
Ceylon to the Gold Coast, 3,650 plants have been raised.

Wardian cases have also been used with conspicuous success.
Each case is made to hold from 1,500 to 3,000 seeds, the earth
and packing material forming alternate layers with the seeds.
From 20,000 seeds packed with moist soil in Wardian cases, sent
from Ceylon to the Gold Coast, some 3,400 plants were raised.

Experiments at Trinidad and Singapore.

Mr. Hart, Superintendent, Botanic Gardens, Trinidad, assures
me that he always keeps Para rubber seeds damp and never dries
them, and objects to the use of charcoal in packing, as he believes
the latter abstracts the moisture from the seeds. Mr. Hart informs
me that coconut dust is best when " tobacco damp," and seeds
packed with tliis material, in small tins of J lb, or so, keep sound,
germinate freely, and do well when disentangled.

The Director, Botanic Gardens, Singapore, has recently sent
quantities of Para seed to Jamaica, Kew, Mexico, &c., with satis-
factory results. The seeds were sent to Jamaica in biscuit tins,
packed in slightly damped incinerator earth, with the upper part
filled witli sawdust to reduce the weight ; the otlier seeds were sent
in biscuit tins filled with damp finely-powdered charcoal.

" In packing, a certain amount of care is required in damping the
charcoal so as to get it equally moistened all tlirougli and not either
over wet or over dry. This is best done by damping tlie charcoal

PARA RUBBER. 275

tlioioughly iuid then drying it in the sun, consistently stirring and
turning it over 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 advazitage of preventing any attacks of mould or bacteria
likely to cause decomposition. Other experiments with powdered
coir libre and coirdust, sawdust, and variously prepared soils have
been tried, but the results do not seem to have ever been as success-
ful."*

I am obliged to Mr. H. F. Macmillan, Curator of the Royal Bo-
tanic Gardens, Peradeniya, for the following notes on the methods
of drying and packing seeds of Para rubber : —

" Unless the seeds are sown or despatched almost as soon as
collected they sliould 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 lias to be dealt with a quantity
of broicen-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; nor should they, on the other hand, be
unduly exposed to sun heat. Small quantities of Hevea seeds may
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 fort-
night to three weeks ordinary strong cases, about 30" x 16" x 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 hght 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 effect
of preventing the growth of mould on the seeds and thus prolonging
their vitaHty, but its application is unnecessary, except perhaps in
extreme cases. B3- far the most satisfactory means of transporting
Hevea seeds is by way of Wardian cases."

* Straits Agricultural Bulletin, 1900.

276 PARA KtBBEll.

Wardian Cases!.

The principle of the foregoing methods, it will be seen, is to re-
tard 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 the saving in the long run
is evident. If good seeds are sown they will germinate in about ten
or twelve days, and the percentage of failures would be nil ; the
seedlings may then be tended in the cases as if they were in a nur-
sery bed, and an opportunity of shipping may be awaited without
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 " stumps." Tlie principle of tlie 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 de-
cayed coconut dust, with a sprinkling of charcoal) ; upon this
in placed a layer of about 1,500 seeds ( or if necessary two layers
of 1,000 each with compost between), finishing with a covering of
about an inch of compost. The whole is then thoroughly watered,
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 insides of the case. The latter is then
raised on four bricks to allow the escape of water as well as to pre-
vent 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 light, 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, which may mean a
year gained in planting, only costs about Rs. 5 per thousand more
than the price actually paid for seeds that have been packed and
despatched in the dry method — that is allowing for 50 per cent, of
these to germinate and the cost of tlie Wardian case to be Rs. 15.

Ridley maintains that the Wardian cases are expensive and
unsatisfactory and considers that the method adopted in Singapore
of packing in slightly damped charccal or burnt rice dust lias
given better results. He is strongly against using cocount dust and
saw dust.

CHAPTER XXI.

ESTIMATES OF RUBBER PLANTERS:

COSTS OF PLANTING RLIIBER IX CEVLON, MALAVA,

JAVA, SOUTH INDIA, AND BORNEO.

EstimatH I. by E. Gordon Reeves, Rs. 322-40 per acre at end of ^th
year for' Matale — Estimate II. by F. J. Holloway, Rs. 283"50 per
acre at end of Gtli year. — Estimate III., I^eradeniya District
for first two years — Estimate IV., Kalutara District for first
six years — Estimate V., Ambalangoda J^istrict for first two
years — Estimate VI., Ambalangoda District for first two years
in swampy land — Estimate VII., Ambalangoda District for first
two years. — Estimate of cost of developing 500 acres under Para
rubber in Malay Peninsula, upkeep of same and returns up to
the eighth year by Stanley Arden — Cost of planting IdOO acres
and profits therefrom in Malaya, by Carnithers — Growth on
Seafield Kstates — Cost of planting rubber and profits ther.'from
in Java, by Xoel Bingley and A. H. Berkhout — Estimate of cost
of 300 acres of Para rubber in South India, by E. G. VVindle. —
Cost of planting Para rubber in Borneo.

rp^HE cost of clearing, draining, and planting up large acreages of
_L Para rubber necessarily varies according to the condition of
the forests to be cleared, the nature of the land, and the rates of
wages paid, &c. The following estimates liave been kindly supplied
to me by friends in Ceylon. (Rupee =\s. 4d.) :—

ESTIMATE I.

Estimate of Cost of Purchasing 100 acres of Land and Planting

WITH Para Rubber.
Cost of 100 acres of Land —

Forest say @ Rs. 60 per acre )

Chena „ 40 to Rs. 45 ^ ^^^

Clearing —

100 acres Forest @ Rs. 20 per acre \
100 acres Chena @ Rs 15 to Rs. 17 ) ^

NtTESERiES AND Seeds — 40,000 seeds at

Rs. 7 per 1,000
30,000 Baskets, Rs. 4 per 1,000
Making nm'series, including sheds for

basket plants, sowing seed
Upkeep, watering for 3 months regularly
Further occasional attendance for six

months .. .. . . 20 0

. . 510

Roads and Drains — at Rs. 6 per aero . , . . qOO

Lining — say 15' by 15' — about 200 trees per acre, including

cost of pegs, @ 75 cents per acre . . . . 75

Carried forward 7,935

Rs c.

Rs.

50 0 per acre .

. 5,000

17 50 per acre .

. 1,750

280 0

120 0

60 0

30 0

^78

PARA RUBB£)R

Brought forward . .
HouNQ — Holes 18" by 12": task 40 per man, say Rs. TSO
per acre

Planting — 20,000 Basket plants including tx'ansporC from
nurseries : dipping in liquid manure, &c., 80 cents per
acre

Rs.
7,935

180

Supplying — Putting out 6,000 basket plants
100

50 cents per

Shading— 30,000 cadjans @ Rs. 10 per 1,000 Rs. 300
Making up : fixing and general attendance,

say Re. 1'50 per acre . . . . ,, 150

— 450

per acre

Lines — 1 set of temporary lines, 20 rooms : jungle post
thatched roof ; mud and wattle walls ; @ Rs. 20 per
room
Weeding — Forest land : first 3 months ) say 10 months' weeding
at Re.1'25; thereafter @ 80 > of 1st year at Re. 1*50
cents J

Chena Land : )

- • First 3 months @ Rs. 2-50 f
Second 3 months ,, 1*75 T
Thereafter ,, 1' 0'

Fencing. — Cost of wire and staples'!
about Rs. 150 per mile, j
3 wires at 1 foot apart 1
Posts: cutting holes, &c., f
and fixing, Rs. 30 per mile |
Carpenters at Rs. 7 per mile j
Tools, say Rs. 100 i

Contingencies, Rs. 100 )
Superintendence at Rs. 100 per month
Coast Advances ; 80 coolies say Rs. 30

400

1,50

Rs. 187 per mile allowed—
per 3 miles . . 561

200

1,200
2,400

Brought forward, first year's expenditure
Add interest at 7 % say

Rs.

2nd Year . . Superintendence say . . 1 ,000

Weeding 100 acres at Re. 1 . . 1,200
Nurseries, supplying cadjans,

&c., .. 105

Roads and drains upkeep . . 50
Thatching lines Re. 150 per

room . . 30

Upkeep of fence . . 50

Contingencies ... 100

Add interest on Rs. 18,611 at 7%

Rs. 14,936

. . 14,936
1,045

Rs 15,981

2,636
1,290

Can'ie 1 forward

19,806

PARA RUBBER.

279

Brought forw ard

19,800

3r(.l Vcar Superintendence

.«•

900

Weeding at 80 cents

...

800

Supplying and niu-series

100

Roads and drains

..•

Lines

, ,

Fencing

•-.

Contingencies

...

100

2,010

Add interest on Rs. 21,816 at 7%

• •

Rs.

1,527
23.343

4th year ... Superintendence

.9.

720

Weeding at 75 cent?

...

750

Supplying, &c.

100_

Lines : 20 rooms — permanent

stone pillars, mud and wattle

walls, iron roof, Rs.

70 per

room

. ,

1,400

Fencing

. .

Contingencies

3,070

Interest at 7% . .

* *

Rs.

1,848
28,261

5th Year , . Superintendence

. ,

,900

Weeding

. .

750

Fencing

. .

Contingencies

. .

Roads &c., ana general

atten-

tion

••

100

1,870

Interest at 7 %

• •

••

2,109

Rs. 32,240

Rs. 322*40 per acre at end of f^fth year.

Memos. — I close the estimate at termination of the fifth j'^ear as it
is now generally admitted that tapping may commence according
to growth between the end of fourth and sixth years.

The estimate is fi'amed on the lines of Rubber planting as ordiiaarily
carried on in the district of Matale, and might serve as a guide to the
jjlanting of Rubber in such districts as Badulla Valley, Kurunegala
Dumbara, &o., districts usually not heavily influenced by the rams 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.

280 PARA RUBBER.

Roads and Drains. — The cost would be from Rs. 5 to Rs. 8 per
acre according to lay of land, soil, &c

IFencing. — 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 establisliod rights of way. My
estimate is for a treble wu'e fence.

It is not at all certain that it would not pay in cases where clearings
have a jungle frontage to put up 2 wires only say at 1 foot 6 inches and
3 feet, backed by galvanized wire 3 feet by 3 inclies mesh.

The cost of the barbed wire fence would be reduced to Rs. 50 jier
mile. The galvanized wire would cost about Rs. 285 per mile. Tlie
total cost of such fencing would therefore work out at about Rs. 422
per mile.

It would effectually put as top 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 vise of basket plants and shading with cadjans 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 s 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
shouldbe reduced in either forest or chena land clearings to an average
of 75 cents per acre.

Superintendence. — Has been estimated for on the supi^osition
that the clearing is being looked after by the manager of an adjoining
property. In the case of an estate of considerable acreage being con-
cerned this item would be chargeable at Hs. 10 per acre per annum
all through.

Buildings. — I make no estimate for Factory, Superintendent's
Bungalow, &c., though both would be required. Superintendent'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 Factoi'y, as the invention of suitable machinery, wliich is sure to
follow during the next year or two, will revolutionise the curing of
Rubber. It wovild 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 as an ordinary item of oxpend-
iture. 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 ^a
the estate as Superintendence or any other item and should be rec g-
nised as such. The amount Rs. 2,400 would probably bo exceeded
from and after the sixth year on tapping operations commencing.

E. GOIIDOX IIEFVES.

Wiltshire,
Matale, October 10, 1905,

PARA RUBBER. 281

ESTIMATE IT.
Paka RuBUEii IN Central Province.

EsTl.MATK FOR OPENING LaND AND NOTES ON Sa.ME.

Ill making an ostiinato for opening land there are many things to bn
taken into consideration, such as (1) 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) laj^ of land — if the land is fairly
flat with few rocks or stones the work Avill be much cheaper than on a
rocky and hilly 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 felling 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 di'ains 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.

I have slightly revised my estimate as published in the India-Rubber
Journal of May and June, 1904, and have now brought it up-to-date,
having benefitpd bj^ the experience in opening 869 acres during the past
twelve months.

The following estunate is made for an estate in the Central Province
worked entirely by village labom-. Lay of land, mostly on hillsides,
with a fail' number of rocks — average cost of labour about 40 cents per
day. I strongly advocate seed at stake in all new clearings.

Estimate of purchasing and opening 300 acres of Land.
1. — Purchase of land, sajr 300 acres, at Rs. 50 per acre . .Rs. 15,000
2. — Felling, bm-ning, clearing, rooting 300 acres, at Rs. 15

per acre . . . . . . . , 4,500

3 . — Roads and drains , blasting and building , at Rs 1 2 per acre 3 , 600
4. — Lining and pegs, 15 by 15, at Re. 1*50 per acre . . 450

5. — Holing 2 ft. by 15 in. and filling, at Rs. 6*50 per acre . . l,9jC
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, ToO per acre . . . . . . 450

9. — Weeding, April to December, at Rs. 20 per aero . . 6,000

10.— Bungalow Rs. 2,500, lines (20 rooms) Rs. 600 .. 3,100

11.— Superintendent Rs. 3,000, Conductor Rs. 600 .. 3,600

12. — Tools and contingencies . . . . , . 750

13. — Barbed wii-e 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 . . . . . . . .* 1,500

(If 2-in. wii-e netting buried and put in ground — and 3 strands

' • *t of barbed wire and erection, at Rs. 9 per acre.) 42,550

'ind to 6th year supervision, Rs. 3,600 . . .. 18,000

Weeding second year at Rs. 20 per year, Rs. 6,000 -j

,, thirdyear at Rs. 15 per year, Rs. 4,500 (. 19,500

,, fourth to sixth year at Rs. 10 per year, Rs. 9,000 J
Upkeep of roads and drains at Re. 1 per acre. 5 years at Rs. 5 , . 1 ,500

Carried forward .. 8J,.').'^^0

^ no)

282

PARA RUBBER.

Brought forward
Upkeep of lines and bungalow, &c., 5 years
Supplying and attending young plants, 5 years at Rs. 200
Sundi'ies and contingencies, 5 years at Rs. 250

Rs.
81,551
1,250
1,000
1,250

Total cost of 300 acres, at Is. 4cZ.=£5, 670 or £18 18s. per acre. Rs. 85,050
October 14, 1905. FRANCIS J. HOLLOW AY. '

ESTIMATE III.

First and Second Years — Peradeniya District.

First Year. Second Year

Superintendence . . Rs. 10 0 Rs. 10 0

Felling

Lining, 18 feet by 18 feet
Pegging

Roads and drains
Fencing with barbed wire
Holing

Filling and planting
Plants
Weeding
Buildings . .
Tools

Contingencies
Supplying andfencing

ESTIMATE IV.

First to Sixth Year — Kalutaea District.
The following estimate of the cost of opening up Para 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. 180 to Rs. 200 per acre.

1 si year, 2nd year, 3rd year, 4th year, 5th year, Gth year.
Rs, c. Ra. c. Rs. c. Rs. c. Rs. c, Rs. c.

1 0

—

15 0

1 50

14 0

—

6 0

—

3 0

—

1 50

0 50

10 0

9 0

8 0

0 25

0 50

—

2 0

—

2 0

84 0

23 25

Felling and clearing

—

Drains

—

Roads

2 0

1 50

Holing and filling . .

— ■

—

Lining and pegs . .

—

Weeding

16 0

12 0

Fencing

2 0

1 0

Plants . ,

—

Planting

2 0

—

Tools

0 50

—

Superintendence . .

5 0

b'urvey, «&c., and

contingencies . .

0 50
28 0

0 50
21 50

1 0
20 50

1
20

0
0

Total~Rs. 183.

PARA RUBBER. 283

ESTIMATE V.

First and Slicond Yb:.VRS — Ambalangoda Uistrict. — Cost per Acruj.

Fii'st Year. Second Yoac
Ks. c.

1 50

Rs.

Felling and clearing . . . . 10

Lining and pegging . . . . 2

Roads and di-ains . . . . 15

Fencing with barbed wii'o . . 5

Holing .. .. .. 9

Frilling and planting . , . . 7

Plants .. .. .. 1

Weeding .. .. ,.12

Contingencies . . . . 2

.Supplying and fencing . . . . —

ESTIMATE VI.

0 50
12 0

1 0
1 50

FmsT AND Second Yeak — Ambalangoda Distkiot.

Principal Items in opening Swampy Land.

First Year. Second Year
Ra. c. Ks. c.

Felling and clearing

liining and joeggiug

Roads and drains . . . . 30 0 . . 10 0

Heaping soil

Fencing with wire

Filling and planting

Weeding .. . . 24 0 . . 24 0

Contingencies . . . . 2 0 . . 10

Supplying, &c. . . . . — . . 1 50

ESTIMATE Vir.

Estimate of Opening One Acre under Rubber in Low-country,

Ambalangoda.

Superintendence

"Cost of watering and rearing plants, per 1,000

Felling and clearing

Lining, 20 by 20

Hohng and filling in, 2 by 2 by 2

Planting

Wear and tear of tools

Weeding, per month. Re. 1'50

Drains

Roads

Supplying

Fencing with barbed wire . .

68 50'

Ks.

284 t'ARA RUBBER.

No bungalow or lilies estimated for in either first or second year.
Cost of plants or watchman not taken into consideration, tho cost of
former being too fluctuating.

SECorro Year. Rs.

Superintendence . . . . .-.5 0

Weeding, per acre per month. Re. 1 , . . . 12 0

Supplying . . . . . . ..10

General upkeep — drains, roads, and contingencies . . 5 0

23 0

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.

ESTIMATE OF COST OF DEVELOPIXG 5(t(l ACI5ES IXDER PAKA RlBBEIi

I\ MALAY PEMX.SULA AM) UPKEEl' OF SA.IIE (WITH RETUKXS)

UNTIL THE EIGHTH YEAR,

Bv Stanley Akden. ijj!

Co8T oi' Lanj> —

* Premium on oUU acres at $3 per acre

1,500
500
150

Quit rent lirst year .'^1 per acre
Survey fees. Registration, etc.
I'lELD Works--

Felling junj^le— 250 acres at ."rsy per acre ... ... -J.-JoO

Burning oft" and Clearing up '250 acres at ">>'■> per acre ... 1.250

Di-aining and Inspection Paths 250 ., ,, sl2 ,, .. ... 3,000

Lining oiicluding cost of pegs) ,. ,, ,, §1-50 ,, ,. ... 375

Holing- 150 per acre— and tilling with surface soil 82 per acre 500

Planting with Stumps from Nurseries $1 per acre ... 250

Supplying, 50 cts. per acre ... ... ... 125

Nurseries, preparation of Seed Beds, Sowing, etc. ... 250

Seeds, 100,000 at $6 per 1,000 ... ... ... 600

Weeding 100 acres 9 months $1 per mensem ") , y,„,

150 ,, 6 ,, $1 ,. ., 3 •■■ ^'^""

BUILDINCS —

Superintendent's Bungalow ... ... ... ],000

Barrack furniture for same ... ... ... 250

Bungalows for Apothecary and Conductor ... ... 500

Cooly Linesto accommodate 200 coolies. 50 rooms at $3U per room 1,500

t Hospital ... ... ... ... 500

Sundry Buildings— Rice Store, Tool Store, etc. ... 250

Ui-ERVISIOX —

Superintendent's salary $300 per mensem ... ... 3,600

Apothecary's ,, $75 ,, ,, ... ... 900

Conductors ,, $50 ,, a ... ... 600

MirfCELLAXEOUS— '

Tools and Implements ... I ... ... 500

Immigration expenses, loss on Coast Advances, etc. ... 1,000

Ceneral Transport. . ... ... .. 250

(/ontingent expenses. Medicines, Postages, et«.... ... 1,000

* After the sixth year the quit rent is $4 per acre.

t The cost of erection of a hospital and salary of a qualified Apothecary are inclined, ap fly a
eccnt otiacttnent Government now requires each estate to erect a jipspinl

TAKA llUBBER 285

KSTIMATK 01" «'OST IN II AL.VY PKMXSILA- -C('/<^<

•Jiul yuar ... Cost of opoiiiiif; •J5U acres as abovo ... ^'24, HlU
Leas pvemiuin ... $I,5UU

,, Survey Fees ... l.")()

,, Buildings ... 4,(Mi()

."),().■)(!

... IS, 750

Upkeep vi lirst --TiU acres at f^SU per acre ... Tj.'SOU

:$rd year ... ,, ,, 50U acres at $'40 ,, ,, ... 15,000

4th year ... Do ... 15,000

5tli y ear . . . Do ... 1 5, 000

Total Expenditure to end of .Hh year... 95,650

(ith year ... Upkce)' of 500 acres at d'M) per acre ... 15,000

Extra cooly accommodation ... ... 500

Manaf:;er's l)ungalo\v ... ... 2,500

Curini;- and Drying Store, Machinery, etc., (say) ... 10,000

Immigration expenses, loss on Coast Advances, etc. i.',50u
Tapping and Collecting (including cost of knives and

cups) Cluing, Packing, Freight* Export Duty, etc.

•_'5,n(»0 lbs. Rubber at 50 cts. per lb. ... 12,5C0

Total expenditure to end of sixth year ... 138,60(.>

Ttli year ... U]>keep 500 acres at s3o per acre ... ' ... 15,000
Collecting, Ciu-ing and Marketing 75,000 lbs. rul)ber

at 50 cts. ... ... ... .37,500

Total expenditure to end of seventh year... 191,150

Sth year ... Upkeep 500 acres at ?^'2i? per aci'e ... ... 12,500

Collecting and Marketing 112,500 lbs. rubber at 40 cts. 45,000

Total expenditure to end of Sth year 8248,6 5

Exchange 2/4 = ??1 ... §29,253

ESTIMATE OF RETURNS FROM RUBBER.

6th year ... 250 acres (375,000 trees) at y lb. per tree, say i' d: d

100 lbs. dry rubber per acre — 25,000 lbs.
at 'St<. per lb. ... ... 3,750 0 o

7th year ... 25o acres as above — 25,000 lbs. -- £3,750
2.30 ,, at Ij- lbs. per tree, say 200 lbs.
per acre = 50,000 lbs. dry rubber at
3/- per lb. ... ... 7,500

11,250 0 0

Sth year ... 250 acres as above 200 lbs. per acre ... 7,500
260 ,, at 250 lbs. peraci'e = 62,500 lbs.

dry rubber at 'Sd-. per lb. ... 9,375

16,875 0

£31,875 0 0

The present pi ice of ''Plantation Para" is 5*. 3rf. perlb., but for the

Furposes of this estimate I have taken it at 3*'. per lb. It will be seen that
anticipate that the whole of the capital expended on development will be
repaid by the end of the eighth year ; the yield during the ninth year
should nvei-age 300-350 lbs. per acre which, on a selling basis of 3.>'. per lb.
less Is. per lb. for harvesting and marketing, will realise a net profit of
£30 — £3o per acre, which will again be considerably increased during the
tenth year. The cost of upkeep at this stage should not exceed £3 per acre.

JoHOEE, l8t October, 1907. STANLEY ARDEN.

* There is an export duty of 2'j ^ ad valorem

2fi6

PARA RUBBEtl.

MVLAVA.

COST OF i'L ANTING AND TROFITS.

estimatks fuu 1,000 acke estate, '250 ackes to be opened each
Year. F.M.S.

(By favour uf <). I>. Carruthers, Director of Agriculture, F.M.S.)

FiKST Yeak,

Froniiuni

Survey Fees

Rent

Clearing, Felling ami Burning

•_'.")U acres ($1") per acre)
Lining, Holing and Planting

2r)0 acres ($6 per acre)
Plants

Roads and Drams ($6 per acre)
liunoalow

3,UU0
1,000
1,000

Lines

Medical, Hospital Medicines,

&c.

K5U0
2, (too

Lal)our Advances, linniigra-

3,75(»| tion F^ees, &c. ... ... 1,500

Superintendence... ... ;i,(iOO

1,.")00 Tools and Sundries ... 1,000

800 1

1,.J00J $24,150

2,000 1

Seoonu Yeah.

Rent

Clearing, Felling and Burning

250 acres
Lining, Hohng and IManting
Plants ...

Iloads and Drains ...
Medical
Labour

1,000

Superintendence ...

... 4,000

Tools and Sundri(!S

7.50

.S,750

Weeding 250 acres

... 2,500

1,500

Supplying

101)

SOO

1,500

."^ 17,0(111

1,000

Third Year.

Rent

Clearing, Fuelling and Burning

250 acres
Jjining, Holing and Planting

2.50 acres
Plants
Lines

Roads and Drains...
.Medical

1,0001 Labour

Superintendence ...
;i,7."iO Tools and Sundries

Weeding 500 acres
1,500 Supplying

800
1,500
1,500
1,0(1(1

. l,(J(Jli
. 4,(J00
. 1,000
. 6,U00
100

$23,1.50

F'ot;uTH Yeah.

Rent ...

Clearing, Felling and Burning

250 acres
Linitig, Holing an<I IManting

2.")0 acres
Plants

Roads and Drains...
Medical

1,000 1 Labour

Superintendence ...
;5,7.")0 Tools and Sundries

Weeding 7.3n acres
1,5(J0 Supplying

S(»0
1,500
1,000

$
. 1,000
. 4,000
. 1,001)
. 12,000

100

$27,650

PARA RUBBER.

287

MALAYA- CoTi^rf.

Fifth Year.

Rent ...

Roads and Drains

Medical

Labour

Superintendence ...

... 1,000 Tools and Sundries

8U0 Weeding l.OuO acres
... 1,000
... 1,000 i
... 4,000 J

Rent ...

Roads and Drains

Labour

Medical

Superintendence ..

Sixth Year.

1,000
800
1,000
1,000
4,000

Tools and Sundries
Weeding 1,000 acres

. 1,000

. 15,000

SJ3,800

. 1,000
. 17,000

§25,800

Rent ...

... 4,000

Roads and Drains

800

Medical

... 1,000

Labour

... 1,000

Superintendence ...

... 4,000

Tools and Sundries

.. 1,00..'

Seventh Year.

$ Weeding 1,00(1 acres

$17,000
$•28,800

8th ai d following years as

7th Year $28,800

Except that the item for r eed-
ing will rapidly decrease till
the 13th or 14th year it will
be less than §1 ,000

PROFITS.

Seventh Year.

250 acres planted 150 trees per acre at 1 lb. rubber per tree

sold at 3s. per lb.
250 acres planted 150 trees per acre at 1^ lb. rubber per tree

Less cost of production, shipping, etc., of 93.750 lbs. at Is. 6d.
per lb.

Nett profit ...

•48,214
72,321

$120,535

60,268

$60,267

Eighth Year.

250 acres at 1 lb. and 3s. per lb.
., U ,, 38. ,,
,, I „ 38. ..

Less cost of production 253,125 lbs. at Is. 6d.

48,214
72.321
96,428

$216,963
108,482

$108,481

288 PARA RUBBER.

yiALAY A— Oontd.

PROFITS.

Ninth Year.

250 acres at I lb. and Ss. per lb. ...

250 „ „ n „ 3b. „

600 ,, ,,2 lbs. per tree and Ss. per lb.

Cost of production, &c., 243,750 lbs. at Is. 6d.

48,214

72,321

192,856

$313,391
156,696

$156,695

Tenth Year

250 acres at 1 J lbs. per tree at 3s. per lb
750 ,, at 2 lbs. per tree at 3s. ,,

$72,320

289,280

$361,600

180,800

Less cost of production at Is. 6d. per lb. on 262,500 lbs.

Nett profit... $180,800

Eleventh Year.

1,000 acres at 2 lbs. per tree and 3r. per lb

Cost of production &c., of 300,000 lbs. at Is. 6d. per Ib-

$385,710
192,857

Nett profit... $192,853

and so on each year annual profit $192,853 with a probability of stil
increased yield.

Nett
Profits,

ABSTRACT

OF ESTIMATES

'•

Total

Year.

Expenses.

Total.

Profits.

24,150

—

17,900

42,050

—

23,150

65,200

—

27,660

82,850

—

23,800

115,650

—

25,800

142,450

—

28,800

166,250

60,267

28,800

19.5,050

108,481

168.748

28,80t»

223,850

156,695

225,444

28,800

252,650

180,800

406,244

28,800

281,450

192,853

599,Uit7

28,800

310,250

192,853

791,950

28,800

339,050

192,853

894,803

28,8110

367,850

192,853

1,177,656

1,594
153,694
317,647
481,700
645,743
809,806

If 5% interest is added each year for interest on the capital expended
the money total capital expended is not repaid till the 1 0th year.

PARA RUBBER.

289

fiROWTH IN MAL.W.A.

The estimate of yield is intimately connected with the time taken for the
trees to attain a tappahle size, and the following statement issued in March,
19(KS, by the Directors of the Seaheld Rubber Company is of interest: —

GlETHB.

Planted. ^l^^'
age.

Under
9 in.

9 in. to 12 in. tojlS in. to
12 in. 15 in. 18 in.

18 in.
& over.

1904 ... ... 238J

190.O (April— June) ... 159
19(1.1 (Nov.— Dec.) ... 272
19116 ... ... 556J

19<i7 ... ...' 302

9,850
23,098
44,877
78,885
38.772

14,127 17,169
5,697 4,197
5,731 2,307

5,576
253

978

Thest/ measurements show the sizes

of trees

December 31st,

19117.

.JAVA RUBBER

PLAXTIX(

INOLEV.

By Noel B

HkaD of E.XPENMTIKK,

(rKNERAL EXPENDITURE including : —

Salaries, Tools, Stable.

Contingencies, Post and Telegrams,

£. s.

£.

d. £

. s.

£. .s.

Etc., Etc.

.. 2 1

Inventory :—

(Road Tracer, Safe, etc.)

BriLDiNos :—

Bungalows and Lines,

New Rubber Clearings :—

Stumps

1 17

Seed . .

lit

Nurseries

Felling, Clearing and Burning

. 1 0

9 I

1 9

Digging and Forking

Roads and Drains

Lining and Holing ...

Planting ..

•>

Supplying and Handling

Weeding

Barbed Wire Fence

Pests and Extras

«j

—

Rubber Cultivation: —

Up-keep Roads and Drains

()

—

Weeding (including uprot>ting tree

Stumps)

. 1 11

—

Digging and Forking

—

Supplying

• >

—

Pests, Extras, Topping, etc.

—

£.10 0 7 8 3 0 6 11 10 6 4 11
(A) Is an Estate where work has been in progress for 28 months —
Houws !>27 acres being planted Hevea. 441 Acres wore planted 190,".-G, 2G2
in U)itG-7 and •'24 in 1907-S planting seasons. The cost of (leneral Expenditure
is for the whole i>eriod, and calculated over the whole !»27 acres. Tlie
planting season in Java extends generally from Xovend>er to en»l February.
This Estate is mostly Hat with a few undiUating hills and re(jnire8
deep draining. (Cuntlntieilorer.)

(37)

290 PARA RUBBER.

JAVA RUBBER PLANTING.- Cout(I.

(A) has a considerable acreage under Catch Crops, bnt all general Expen-
diture has been charged to Rubber in above table.

(B) Is an Estate where work has been in pi'ogress 20 months — 540
Bouws — 945 acres — are planted with Hevea of which 175 acres in 1905-6, 287
1906-7 and 483 in 1907-8 seasons.

Cost per Acre under General Expenditure, calculated on same basis
as in the case of Estate "A".

This Estate is of a still more Hat alluvial nature corresponding closely
to the lie of land on Lowlands and Highlands Estate in the Klang District
of the F. M. S. and requiring the same system of deep draining.

(C) Is an Estate of a more hilly character, with little heavy forest
on it (which accounts for the cheaper cost of felling and burning) upon
which 850 Bouws, 1487 acres, have been cleared and planted in 10 months.

(D) Is of a similar lie of land to "C" but was partly heavy Forest and
partly second growth and waste land. Here 770 Bouws- 1817 acres — have
been cleared and planted.

In the case of the two last Estates there has been no opportunity of
laying down nurseries before the first year's Clearing, so that stumps had
to be bought costing respectively on Estates about 2U1 & 2;}d each or
£. 1. 17. 6. against the 15s to £. 1 per acre seed and nurseries would have
cost.

On the other hand as will be seen from above table the character of the
land afforded a considerable saving under "Drains'' compared with "A" &
"B" "

Omitting the Expenditure under Rubber Cultivation on upkeep of the
older Rubber during 1907 in the case of the two older Estates "'A"' & "B",
the above figures ot the four Estates shew an average cost of £. 6. 11.11. per
aci-e for opening up and Planting an Estate in West Java, inclusive of
management, buildings, and all general expenditure extending over 2^
years in the case of "A" & "B".

ESTIMATE FOR 1.000 BOUWS RUBBER IN THE PREANGER
RESIDENCY OF .JAVA.

(Planting Distance, 20 x 10.)
(One bouw eqiials 15 acres ; One guilder equals l.f. 8</.)

First Year.
Genekal Expenditure: —

Salaries : — Manager ... per month at (r

Assistant ... ,,

Visiting Agent ,,

Book-keeper ... ,,

Tools

(Stable and Cattle

Contingencie?

Native Festivities

Coolie Brokerage

New Lines

House for Manager ...

Ofljce and Stationery ...

Medical

Roads and Bridges

i. 350

125

KJO

7,200

120

500

2,000

200

250
1,000

4,000

300

?»

100

1,000

Carried forward ... G. I6,t',7<»

PARA RUBBER.

2&1

JAVA KLUUElt PLANTING. -CWW.
Brought forward ...
CLliAKiM; 250 Borws Rlbbeu :—

Nursorios inchuling i)urc'ia8o l.")(»,()Ui> Uublior seed at

(<'. 1") por l.ooii ami Transport on same
P^olling and (Moaring at (J. 2."> per Hoiiw
Diainnig ... „ 10

Lining

•>

Holing

\\ -i

Planting

Roads

...

Fencing

Wet ding

6 Months

1-'

Digging

Allangs ,

1 eets

Extras

G. 1G,(J70

G. 5

»,ooo

6,250

2,500

500

1,000

750

500

1,250

3,000

2,500

250

G. 40,420

ISecojjd Yeak.
L'leaking 250 Bouw.s ani> Ui"-keei' ;^of Existing 250 Bol w.s.

GtNElt.AL EXI'EMHTL UK .—

Salaries : — Manager ... per month

Ist. Assistant ... ,,

2nd. Assistant ... ,,

Visiting Agent... ,,

Book-keeper ... ,,

Tools

Contingencies

Stable

Coolie Brokerage

Now Bungalow (Assistant's)

New Lines

L'p-keep Bungalows

Up-keep Lines

Upkeep Roads

Native Festivities

Stationery and Medical

New Roaas and Bridges

New Cleakixo : —

250 Bouws at G. 95 per Bouw (for details see hrst yeai
Up-kekp 250 Bouws :—

Roads Repairs
Weeding
Up-keep Drains
Supplying
Pest, &c.

at G.

• •■50 per bouw
-M-UO
-■00
0-50 „

roo

at G. 4U0

„ 150

„ 125

„ 100

,, 50

G. !),900

G. 100

...

„ 2,000

„ 300

...

„ 200

,, 500

,, 1,000

„ 250

„ 300

,, 100

>••

„ 30(J

„ 500

••

„ i,m)

G. ltj,450

■•) 1

G. 23,750

A. 125

„ 5,250

,, 500

125

250

G. 6,250

G. 4(5,450

2U2

MRA RUBBElt.

JAVA RUBBER FLAMING. -Coh^/.

Third Yeak.
Clkaking 350 Bouw.s and Up-keep of Existing

(Jkneual Expenditurk : —
Salaries: — MauaKer

1st. Assistant
'2nd Assistant
Visiting Agent
Book-keeper

ToolB

Contingencies

•Stable

Coolie Brokerage

New Bungalow

New Lines

Up-keep Bungalows

Up-keep Lines

Up-keep Roads

Native Festivites

Stationery and Medical

New Roads and Bridges

New Clbakino : —

"250 Bouws at G. 95 per Bouw

Up-keep 5U0 Bouws : —

•250 Bouws at G. 18 per Bouw
250 ,, --'5

per uioutli at G.

5U0

Bouws.

450
150
125

100
50

10,500

100

2,000

300
200

500

1000

250
300

100

300

500

1,000

4,500
6,250

G. 17,050
a. 23,750

10,750

51,550

Fourth

Yea

CLEAKl.\<i 2.')0 Bouws

AND Up-

KEEP

ExiSTl.N

r, 750 Bouws,

(Jeneual Expendituke :—

Salaries ; — Manager

per

month

at G.

50<,l

iBt Assistant

150

2nd Assistant

»■>

125

Visiting Agent ...

100

Book-keeper

...

»i

50
(i.

11,100

Tools

100

Contingencies

2,000

Stable

300

Coolie Brokerage

))

200

New Lines ...

))

1,000

Up-keep Bungalow

...

250

Up-keep Lines

300

Up-keep Roads
Native Festivities

100

300

Stationery & Medical

500

New Roads & Bridges

1,000

New Cleabino :~

250 Bouws at G. 95 per Bouw

Carried forward

G.
G.

a. 17,150

23,750
40,900

JAVA UlUHER l'LAXTIX<; Cuiil''.

.. , -.,, n Brought foiwan I ... G. 4U,yw

•_'.'>•> Boinvs at (!. lo per ISouw ... (1, ]i,lo(}

•JoO ,, IS ... ., 4,.")i)<»

'_'.")U ., •_'.") ,, ... ... ., t),-jr(t

G. 2,5U0

,, 3,750

,, 4,oUU

,, 6,-_'5()

17,000

IS, 000

G. 35,000

(t. I4,oOU
,, 55^00

FlKTH YkAK.

Upkeep 1,0U0 Bouws : —

•JoO iloinvs at (J. 10 per Bouw
L'5<» ,, 15 ., ...

•-'50 ., 18 ,, ...

•250 ,, '25 ,, ...

General Expenditure

Sixth Yeak.
Up-keep 1,000 Bouws: —

500 Bouws at (i. Kt per Bouw G. 5,000

250 ,, 15 ,, ... „ 3,750

250 ,, 18 „ ... ,, 4,500

' (i. i;i-_'5n

General Expenditure ... ... ,, 18,000

New Factory, Washing Machine etr. ... ... ^^ 400(1

Tools (new) ... ... ... „ i'oo(j

Harve.sting* 37,500 lbs. Rubber at (J. 0'5U ... ,, 18,750

ii. 55,000
* 250 Bouws 300 trees-75,000 trees at i lb. 37,500 lbs.

Seventh Ybak.
Up-koep 1,000 Bouws : —

750 Bouws at G. 10 per Bouw
250 ,, ., 15 ,,

General Expenditure
Repairs Factory etc.
Harvesting *S4'375 lbs. Rubber at 050 ...

*250 Bouws by 250 trees = 62,500 trees at v = 46,875 lbs.
250 ,, 300 ,, 75,000 ,, h = 37,500 ,,

84,375 lbs.

Eighth Year.

Up-kee[t 1.000 Bouws at G. 10 per Bouw ... ... G. lo,0(Mj

General Expenditure ... ... ... ^^ 18000

New Tools ... ... ... ]' '5yy

Harvesting *134,.375 lbs. Rubber at G. n-5n ... ',' 67,188

G. 95,688

*2.50 Bouws by 200 trees ^ 50,000 trees at 1 = 50,0UU lbs.
250 „ 250 ,, 62,500 ,, .^ = 46,875 ,,

250 „ 300 ,, 75,000 „ J = 37,500 „

134,375 lbs.

7,500

3,750

18,000

260

42,188

71,688

294

PARA RUBBER.

JAVA RUBBER PLAXTIXG Contd.

NiNTU Yeak.

Up-keep 1,000 Bouws at G. 10
Gonoral Expenditure

Harvesting *-JOO,000 lbs. Rubber at G. U-jO

*-J50 Bouws by 175 trees = 43,750 trees at U = 65,625 lbs.

•250
•250
•250

200
'250
300

,, 50,000
,, 62,500
„ 75,000

1 = 50,000 .,
e = 46,875 „
i = 37,500 .,

•200,000 lbs

Tenth Y

EAR.

Up-keop 1,000 Bouws at G. 10
General Expenditure

Tools (new)

Harvesting *2o0,000 lbs. Rubber at G. 0-50

•250 Bouws by 175 trees = 43,750 trees at G. 2 = 87,500 lbs.

•250
250
25tJ

175
200
250

43,750
50,000
62,500

U =- 65,625

1 = 50,000

ti =- 46,875

250,000 lbs.

lo,ouo

18,(100
100,000

G, 128,000

10,000

18,000

500

125,000

G. 153,500

6au Yeaji
7th Year
Sth Yeak
;»TH Yeak
liiTH Yeak

Yeaks.

1st
2nd
3rd
■ 4th
5th
6th
7th
Hth
<»th
10th

RECEIPTS.

37,500 lbs. at 38. nett per lb. = £. 5,6'25

84,375 ,, ,, ,, ,, 1'2,656

134,375 ,, „ „ ,, -20,156

200,000 ,, „ „ ,, •29,99!)

25(1,000 „ ,, ,, ,, 37,499

SUMMARY.

EXPKNDITUHE. ReCEH'TS.

40,420
46,450
51,550
55,400
35,000
55,000
71,688
95,688
•28,000
53,5UO

67, 5(JU
151,872
241,872
359,988
449,988

Caimtal
Required.

( }. 40,4>20

., 46,45(t

., 51,55(t

,, 55,400

,, 35,00(1

= 67,5(JO
= 151,872
= 241,872
= 359,988
^ 449,988

Profits.

P2,500

80,184

146,184

231,988

296,488

G. 732,696 G. 1, •271, 2^20 (\. •2-28,8-20 G. 767,344

(Signed) NOEL BINGLEY.

Tji Wangle Estate, March, 1907.

PARA RUBBER.

295

itf

teas

O .«

« o

s •<
W* -

?«

ra^

a> a;

5 5 5 5 i ? § 5 i

CO O -»• O O ^1 I-- o c

o c^ o c o
o o =^ o o

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o o o o
o o o o
5^1 t- o o^

o o o o

o o C' r

-XI C -r O I

05 — I — >

I I •■=>

o o

g§?s§

•J5 o -)< o .-: I Ti^i- I

ooooo oo o

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ooooo o o
ooooo o o

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ooooo o o

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ooooo o

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-:!-i!^i I

ooooo

O' o o — o

I -Ji o_-t - -

O O I ^■l I ; C<I

o o
o o

o o o o o o o

O O 00 = 00000 ■_•

O O 0 0=00000 o

'^ t Z. It CO It -t O O 'M ">« 1 1 0>_

ooooo
o = o o o

CO O It •>) tl

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2 ■§

296 PARA RUBBER.

ESTIMATE OF COST IN SOUTHERN INDIA.

ESTIMATK FOR OPENING 300 AflRES IN PaEA RuBBER, WITH

6 YEARS Expenditure.

This has been framed as an average result of opening in various dis-
tricts and at elevations varying from sea-level to 3,(J00 feet, with rainfalls
from 45 to 13.') ins., pay 3 as. to G as. (18 to 36 cents) and other conditions
differing almost as much. I do not include steep land, as I do not recom-
mend such being opened, consequently though rates for roads and drains
may appear low.

Purchase of Land is presumably from private ownei'S. The British
(Juvernment shows no disposition to throw open suitable land ; Travancore
and Cochin have of late refused many applicants, and the Mysore Govern-
ment, though it has agreed to a conference on the subject in August, and
may possibly grant applications, does not posses land at those low eleva-
tions which are i-ecognised as most desirable. Still there is a good deal
available, varying from rather over '2,0U0 to 3,;jO(J in Mysore and the Wynaad,
in Government and private hands, which, if carefully selected, will grow
rubber. On the plains suitable land can be got from native owners, but
great care must be taken with the titles.

Frllino and Clearing vaines from Rs. 10 per acre in an ordinary hill
district to Rs. 3U for the enormous evergreen forest on the Anamalai Hills.
Rs. 15 suffices for good forest at foot of the ghauts.

Nurseries. — If these were put down in the previous year actual cost
would be say as follows : —

Rs.
100,(.00 seed at Rs. 78 as. per 1,000 delivered ... 750
Making Nursery and Fencing ... ... 350

Upkeep ... ... ... 450

Rs. 1,550

but this would involve commencing operations in July at least, instead of
with felling in December, — and cost of superintendence, lines, etc., in the
meantime. I do not niclude cost of baskets, as the plants would not go
into the field before end of May following, and they do better in beds mean-
while, whilst, if they are in baskets, the roots have got far beyond the
decaying remnants before May. Germinated seed in baskets may be used
for planting and often does fairly, and seed at stake, 2 or 3 in a pit, is at
times very successful, but, so far, I am in favour of plants from the previous
year's seed, stumped ; these cost Rs. 37 per 1,000, delivered on estate, if pur-
chased in Ceylon at Rs. 20 per 1,000. The price in India follows that of
Ceylon, plus delivery charges and a nercentage for the plants being more
on the spot and conse<piently more liKely to come on well.

Tai'Ping should start in the 5th year, and, after six years the estate
should maintain itself. No estimate is made for factory and machinery,
these are left to be paid for out of receipts.

Rs.

1. Purchase of land at Rs. 4(» per acre, 300 acres ... 12,000

2. Felling and Clearing at Rs. 15 per acre ,. ... 4,500

3. Nurseries, G>i,(K)0 plants at Rs, 37 per ],0U(» ... 2,22U

4. Iluu<ls and Drains at Rs. 3 per acre ... ... 900

5. Lining and Pegs \Gh' Hii' less roads and stump8=l.')0

plants per acre at Re. 1 per acre ... ... 3(»0

6. Pitting 2 >: 2' at Its. 2S as. per aero ... ... 7.50

7. Filling pits and planting at Ive. 1 '8 as. per acre ... 450

PARA HRBER. i>97

KSiniATE OP roST IX SOITHKKX \\m\-Uoiit</.

lis.

1,L'0(»
I..JU1I

•2,QW
\'A. Tools ... ... ... ... .">(j(l

14. Manageineiit— Suporintendont at Ks. •2'A) 3,000
Writer ., ,, 50 GOO

Tappal it Coolies ,, ., -il 2;V2

:{.s.-.-_'

J, 4.53

s.
it.

Supnlyiny
Shauiiiy

Us.

as.

»i

lo.

1 1.
I--'.

Weetliuj^
Fencinn
Huildin^s —

Us.

Lilies ...
IJungalow

aiK

III

iiitiiro

(JOO
•_',IMIU

15. Hundries — Advances

500

Medicines, Books, Stationery,

etc,

. 5(.H»

Taxes

300

Contingencies ...

153

1 .ot Year's ... Expenditure bronght forward

L'nd Year ... Weeding

3,000

Supplies

200

Management

2,400

General Upkeep, Taxes, etc. ...

l,.30O

3rd Year ... Weeding ... ... 3,600

Supplies ... ... 100

Management ... ... 1,500

General Upkeep, etc. ... 1,000

4th Year ... Weeding ... ... 3,000

Management ... ... 1,500

General Upkeep, etc. .. 1,000

5tli Year ... Weeding ... ... 3,000

Management ... ... 2,000

(Jeneral Upkeep, etc, ... 1,000

Cth Year ... Weeding ... ... 2,700

Management ... ... 2,000

General Upkeep, etc. ... 1,000

35,900

7,500

6,200

5,500

6,000

S,700
Rs. 66,800

July 31st, 190(i.

E. G. WINDLE.

V\l{\ RIKBEH I\ BKITISH NORTH BORNEO,

The following information, afieeting tlie costs of planting rubber
estates in Borneo, was given in the '• India Rubber-Journal" of Januarv
14th, 19U7 :—

British North Borneo is divided geographically and ethnologically into
four portions:— The East C<»a8t, comprising all land from Cowie Harbour
on the South to Paitan Bay <>n the North, and extending inland as far as

(38)

298 PARA RBBER.

I'.VRA RUBBER IX BRITISH XROTH KORSEO—Coutd.

the st)uri"es of the Segama, Kinabatangan, Labiik, and Sngut rivers ; the
Kudat district comprising all land fron\ Telaga to h>ampanmangaio Point;
the West Coast, from Sainpanniaugaio L'oint to Mengalong and extending
as far inland as Sungi Rayoh ; and lastly the interior, from Sungi Rayoh to
Tambunan on the North, Tomani on the South, and Labau on the East.

Practically all estate labour on the East Coast is imported indentured
labour, the men being brought from Singapore, and costing landed in
Borneo Sl>.") per head for (Jhinese, and $7') per head for Javanese and other
Malays; of these sums ^:U> and ^4« respectively is recoverable from the
coolie, leaving the balance to be looked upon as wages ; the (Chinese contract
is for one year and the Javanese for two years.

Work on a rubber eatate should prove congenial to them, and they will
probably fi)rm the chief labour force of all rubber estates opened in the
Kudat district.

The following are about the rates now being paid for contract work on

j.^jbber estates at Beaufort : —

Jungle felling $3 to $6 per acre.

Jungle felling, lopping, stacking and burning clean $lO to $l.i per acre.
If holing be also nicluded $14 to $15 per acre for all above.

In the interior there are two estates, Sapong Estate, the property of
the Sapong Rubber and Tobac30 Estates, Ltd., and Melalap Estate, owned
by the Manchester North Borneo Rubber Co., Ltd.

The cost of agricultural operations varies very little all over B. N.
Borneo, and the following may be taken as the most usual, and are in a
very few cases exceeded : —

Jungle felling $3 per acre.

Jungle felling, lopping, stacking and burning clean $12 per acre.

Holing 1 i ft. by 1 i feet by 2ft. deep, one cent per holu ($2 per acre of
2U0 holes.)

Hoeing $"> per acre.

Draining, ten cubic feet, one cent.

On locally engaged Dusuns and iiajaus or Kadyans the brokerage only
amounts to $.'> per head for men signing on for one year or more.

'Die soil of liritish North Borneo ecpials, if it does not actually surpass,
that of the Federated Malay States, and is about much the same as that ot
Sumatra. The above prices of various work are as chea]) as anywhere east
of Ceylon, and the climate has also shown itself well suited to Tara rubber,
judging l>y the growth in such widely difterent sjiots as Sandakan and the
ijiterior.

The writer has since received the following letter fioiii an authority
well-versed on labour in Borneo : —

"My own opinion is that ijn an acre will cover the costs in connection
with the planting and upkeei> to the end of the fifth year. In the case of
the Lungkon North Borneo Rubber Cinnpany the cott of felling and
clearing U'lO acres and planting 462 acres with rubber was JC4,4(tf),"

INDEX

INDEX.

A. Pa(;e.

Almoniial Latux 150

Abstract of Estimates 288

Acreage in B. N. Borneo 8

,, ,, Ceylon 5

,, ,, India t»

,. ,, Java S

,, ,, Kalutara District 6

„ ,, Malaya U

,, ,, the East 5

Acetic Acid required for Coagu-
lation 1 74
Action of Heat on Rultber "210
Addition of Water to Latex 1G7
Advantages of Mixed rroducts 255
Ago to Tap 107-109
Albi/.zia 75
Albxnninoids in Kubl)er 2U7
Amazon method of coagulation 169
Analysis of parts of Ruliber tree 72
,, Plantation Rubber

200-252

„ Soils 61, 67, 68

Tacky Rubber 270

Antiseptics, Use of 175

Ants, White 265

Area of Para in Ceylon in 1906 5

,, Planted in December, 19u7 8

Artificial Coagulation 167

„ Heat for Drying 186

,, Manures 72

., Rubber antl Substitutes227

Bamber and Willis's Experiment8l90

Bamber's Analyses of Rubber 202

Bark Renewal, Rate of 151

,, iShavings, Macerators for 216

,, Stripping, Repetition of 145

"J'.ola" Knife 82

Hiffen's Centrifugal 181

IJiecuits, Rubber 239

FJlack and Tacky Rul)l»or 270

Blocking Rubber, Presses for 246

Block Planting 257

„ Rubber, Preparation of 243

Blocks, iSi/e of 245
Fiotanical Characters of Para

Rubber 1 1
Bowman and Northway's Knife84-88
Bridge's Hydraulic Block Pres8e8248

,, Presses 247

Brown and Davidson's Press 246

Pack
Brown and Davidson's Process of

Coagulation
Bubbles in Rubber
Burrs. Twists, and Fasciations

169
196

258

Calcium Chloride for drying 192

Camphor 55

Caoutchouc Globules 156

,, Origin of 156

Care of Para Rul)ber seed 273
Carruthers on Rubber in Malaya 137

Cassava 53

Castilloa, Analj'sis of 108

Catch Crops 51

Centralizing Latex 96

Centrifugal Machines 160

Chemical and Physical Tests 236

,, Properties of Rubber 203

,, Reagents, Advantages

and Disadvantages of 175

Chemicals for Drying 186

Chillies 54

Chisel, Carpenter's 81

Circumference and Height 37

Citronella 52
Climate in Ceylon and other

Rubber Districts 20
Close Planting 45
Coagulated Rubber, Compon-
ents of 178
Coagulation 1 60

,, and Strength of
Rubber 177
CoagiUation by Chemical Rea-
gents 173
Coagulation by Mechanical and

otner Means 182

Coagulation by Smoking 169

,, in Field or Factory 169

., time rofpiircd for 171

Cold and Heat Cures 219

Collecting Latex 95

„ Tins 99

Collet's Knife 83

Comb Pricker b5
Commf)n Articles, Quantity of

Rubber in 223

Comparative Estimates of Yield 135

Compass Tapping 115

Composition of Artiticial Manures 72

,, ,, Green .. 73

INDEX.

Vm:k.

Composition of Uubbor iSoils
., Wutand Dry

Rul)bur
Cortical Tissue, Viekliug Capa

city of
Cost of Plants in Ceylon
Cost of Production
Cotton

Creosote and Wet Rubber
Crepe Rubber

Crotalaiia 71^

Cultivation
Cultivation, Vields, etc.

Da Costa's method of Coagu-
lation

Dadap

Diseases of Para Rubber

■261, 2t)6, -269

Distance, Original and permanent 46

Distriliution of Ceylon rubber 4

,, plants and seeds from

Ceylon -

Dixon's Knife

Dickson's Machine for coagulat
ing and drying

Driiniing

Drip Tins

Drying Exj)eriments at Peradc
niya

Drying of rubber
„ Rapid

E.
Eastern Produce and Estate CV)8

Knife
Kstimated cost of plants in

Ceylon
Estimated cost of |)lants i

Malaya
Kstiuiates, Abstract of
Excision and incision
Experiments in Ceylon

„ ., Heneratgnda

„ Tapping

Karri(;r s Knife

Fasciations

Fat of Para Rubber seed

Fencing

First Seed in the East

Flake Rubber

Foliage, Spread of

Foliar nonodicity

Forest nelts

„ forms of plantation r\dibor'_'38

Fre«iuency of Tapping I l.'.-lKi

Freqent lapping and ipialily I l!»

viold I 17

191

134

•277

143

.33

190

•_'40

172

.'57,

196
41
96

198
IS.-)
217

277

2K4
288
146
182
13U
103

S7
258
273

4t»
.>

241

133

2.54-2o.-»

P.\(;ii.
Freshly coagulated rubl>er, Sulp-
hurizing of 222
Fruit disease in rubber 262
,, periodicity 13
Function of Storing Water 16
Functions of latex I o
Funtumia latex 165, 189

(iirth, Measurements of 35, 50

Golledge's Knife 82

,, Method of ilrying 196

(heen Maniu'ing 73

,, Manures, Composition of 74

C round Nuts 52, 73, 7+

Growth. Rate of 30

Harvey s coagulation 183

Heat and Cold Cures 219

Heat on rubber, Action of 21u

Height and Circumference 37

Heneratgoda Experiments 130

Yields 129

Herring bone tapping 92
Hcvea, Species and distribution 1 1

High tapping 104

History of i'ai'a rul)ber in the

East 1

Holing 41, 42

Hollovvav's Knives 82

India rubber, Properties of 209
Introduction of Para rubber into

the East 1

Java, Rubber growing in 24

Kerckhovo's Knife 87

Kinds of Para rubber 233

Plantation rubber 249

K. L. coagulation 183

Knives for tapping 79

Lace R\ibber 211

Latex, Chemical Analysis of 155

,, Collecting and Storing 95

,, Colouring 221

,, Direct uses of 220

,, Functions of 15

,. General Characters of 158

,, Keeping Liquid 97

,. Non Coagulable IU6

,, J*hysical Properties of 154

Scientific Authorities on 16,18

Spocitic <}i-avity of 1,58

,, Sulphuriisation of 221

INDEX.

303

Pack.

i:i.i4
•_'()
:w

52
212
2?0

LaticiforotiB Systiiii

Leaf Diffrtst'

Leaf Fall

Leimnigrass

Loss in Manufacturing

Low (irado Rubbers

Macailani-Miller Knife Sti

Maeadani's Comb Pricker S.l
Process iif Coatju-

lation 17"

.Macerators for Hark Sliavina.s 21(5

Machine for \\'oikin>; Rubber 214

Malaya, VieMs in i:i5

Manuring 09

„ Experiments 71

Manures, Artiticial 72

Green 73

Marking Trees 98

Mc Kenzies Knife 82

Meal fi'om Para Pubber Seed 273
Measurement of Girth 35,50

Method of Drying 193

Michie-Golledge Machine 182

Millers Knife 86

Mineral Matter in Latex 158

Misuse of Terms 229

Mixed Products, Advantages of 255

Moisture and Price i90

,, ., Strength of RubberlST

Moulds im Rubber 271

Natural Coagulation 165

,, Heat for Coagulation 167

Nurseries 40

Nm-serj'^ Plants and Stumps 259

Olilique Cuts in Tapping 91

Oil from Para Seed 273

Packing, Experiments in 274

,, Rubber 238

,, Seed for Transport 274
Para Description byTrimon

and L'le " 19
.. in Brazil 20
,, Knife and Chisel 83
,, Rubber, Kinds of 23S
,, Rubber, Smoking 235
,, Paring 81
Pask-Holloway Knife 87
Passburg's Driers 194
Periodicity, Ettects of Tap-
ping on' 147
Periodicity, in Brazil and Java 258
Physical and Chemical Tests 236

Physical Properties of Hul)ber 2ti:i

Plantation and Wild Rid)ber 23H

Plantation Rubber, Analysi"; of 252

,, ,, < "olouring of242

Direct Use of 226

,, ,, Forms of 238

Te,<ts with

Vulcanised
Planting, Close

,, Distance of
,, Operations
I'otassium in Washed Rtdiber
Prei»aration of Land
Presses for Blocking
Pricking

„ and Paring in Ceylon
Properties of India K>d)ber
Propagation

,, for Cuttings

Protection for Cups
Protein Matter in Latex

,, Removal of

Proteins and Coagulation
Pruning
Piu-ification bj- Growers

,, ,, Manufacturers

,, of Rubber

Putrefaction

(Quality of
Quantity ,.

Latex

226
45
43

2f »8

246

147

2(»9

•>

95
157
180
1»>4

48
218
211
211
179

103
103

Range in Value of Para Ru))ber 4
Rapid and Slow Drying i05

Re-agents, Effects of lan

Removal of Moisture from Rubber 186
Resin in Latex \-,-j

,, Rubber •ju5

,, Removal of '20li

Resin on Vulcanization, Effect of219
Root Diseases ofjc

Uoot Growth ;{<)

Rubber in Common Articles,

quantity of o^.-^

Rubber in 3Ialaya. Carnithers on 137

in Shavin>;s

i:r>

Soil

in Tyres

224

Yields in Ceylon

139

,, India

13S

,, ,, Malaya

139

,, ,, Singapore

142

the Gold Coast 138

Samoan Rubber Developments !(
■' Scorpion " Paring Knif»i S8

204

INDEX.

I'AtiK.

Scrap Rubber 242

Scrap Rubber, l*uritic;ation of 242

Sculler's Knife 8()

Season t<> Tap 112, 117

" Secure" Knife S7

Seed, Para, ( )il and Fat of 27:i

,. ,, Meal and C!ake -21^

Seed, Packino- of 274
Seeds, What to do with them

272
97
:»
247
135
239
109

Settling Tanks

Shade and Wind

Sliaw's lilock Pre^s

Shaving'3, Rubber from

Sheet Kul)ber

Size for Tapping

Small lots of Kubber, Brokers'

advice 249

Smoking and Coagulation 168

Smoking Method and Plantation

Rubber 235

Soil, Analysis of 61, 67, 68

Soil in Malay States r)9

Soils, Rubber 57

,, Swampy 62

Specitic Gravitj'^ of Rubber, Raw

and Vulcanized 202

Spiral Curves 93

Spiral vs. Herring Bone Tapping 131
Spontaneous Coagulation 167

Srinivasigam's Knife 88

Stem Diseases 263

Storing Latex 95

Straining Latex 160

Structure of Crude Rubber 163

Substitutes for Rubber 222

Su"ar in Latex 157

Sulphurising Latex 221

Freshly Coagulated
Ru})ber 222

Swampy Soils 62

Synthetic and Artificial Rubbei's

and Substitutes 227

Synthetic Pvubber, Definition of 228

Tacky or Heated Rul)bor 179

Tacky Uiibber, Analysis of 270

Tapping 77

,, Area 47

How to Increase 111

Bad 78

,, (Jompass 115

,, Experiments in iu3

,, Frequency of 115,116

High 104

,, Knives 79

,, Season for 112, 117

,, Size for 1<»9

,, Spiral vs. Herring I'one 131

„ Time of Day for 114

P.MIK.

Tapping, Yields l)y Different

Systems t)f 131

Terms, Misuse of 229

Terry's Opinions of S>d>stitutes 23!
Tests with Vulcanized Plantation

R\diber 226

Tin)e of Day for Tapi>ing 1 14

Tisdall'fi Knife " 88

Tobacco 54

Twists 258

Tyres, Rubber 224

Ule on Para Ruliber 19

Use of Plantation Rubber direct 226
Uses of Rubber 225

Vacuum Drying
V-cuts, Yield from

194

128

Vigna

73,74

V-incisions

Vulcanization

218

„ Effect of Resins upon 219

Walker's Combination Knife 87

Wardian Cases 276

Washed Rubber, Characters of 217

Washing Machine 214
Washmg Machines, General

Account of 216
Washing of Rubber 179
Washing, Rapid 217
Washing Scrap & Dirty Rubber 215
Water in Rubber 186, 190
Water Storing of Latex 16
When to Tap l(t7, 109, 1 12, 114, 1 17
Whore to Tap 100
White Ants 265
Wickham's Process of Coagu-
lation 171
Wild and Plantation Kubl)er 233
Willis' Experiments 190
Wind 39
Worm Rubber 240
Wound Response . 101

Y'ields, Comparative Estimate of 125

,, Exceptional 127

,, from Long Spiral Lines 129

„ V-cuts 128

in Brazil 120

in Ceylon 121

„ in Henoratgoda 129,132,135

,, in Malaya 135

., in Peradeniya 127

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