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A   SELECTION  FROM 

MR.  KNIGHT'S 
PHYSIOLOGICAL  AND   HORTICULTURAL 

PAPERS. 


THOMAS  AOT51REW  KKIflJ-HT  E 


JL.S 


Tresideiit;  oi'  Th.e  London  Horticultural  Society; 


^Printed  "bj  IC&N. 


A    SELECTION 


FROM    THE 


PHYSIOLOGICAL   AND    HORTICULTURAL 

PAPERS, 


PUBLISHED    IN    THE 


transactions  of  tj)t  Bopal  antr  Horticultural 


BY  THE  LATE 


THOMAS    ANDREW    KNIGHT,    ESQ., 

\v 

PRESIDENT    OF    THE    HORTICULTURAL    SOCIETY    OF    LONDON,    ETC.    ETC. 


TO  WHICH  IS  PREFIXED, 


A    SKETCH    OF    HIS    LIFE. 


LONDON: 
LONGMAN,  ORME,  BROWN,  GREEN,   AND  LONGMANS. 

MDCCCXLI. 


K  Y-AGRICUCTUmC  DCft 


LONDON: 

BRADBURY  AND  EVANS,  PRINTERS, 
WHITEFRIARS. 


K4 


INTRODUCTION. 


DURING  the  life  of  the  late  MR.  ANDREW  KNIGHT,  he 
was  repeatedly  urged  by  many  scientific  Horticulturists  to 
collect  together  and  republish  all  that  he  had  written  on 
Vegetable  Physiology  and  Horticulture;  and  since  his  lamented 
death  this  wish  has  again  been  repeated  to  his  family,  and 
having  been  seconded  by  the  advice  of  some  of  his  friends 
whose  pursuits  have  well  qualified  them  to  judge  of  the 
probable  utility  of  such  a  work,  it  has  been  determined  to  offer 
to  the  public  a  selection  from  the  Papers  which  at  various 
periods  he  communicated  to  the  Royal  and  Horticultural 
Societies,  in  a  form  that  will  render  their  contents  available 
to  many  persons  by  whom  the  Transactions  of  these  Societies 
are  not  attainable. 

Vegetable  Physiology  is  a  branch  of  science  which  till 
very  lately  has  not  been  very  extensively  cultivated;  hence 
the  number  of  persons  competent  to  judge  of  the  value  of 
Mr.  Knight's  researches  is  necessarily  limited :  but  the  con- 
tinual reference  that  is  made  to  his  papers  in  the  works 
of  M.  De  Candolle,  Dutrochet,  Du  Petit-Thouars,  Feburier, 
Keiser,  and  other  foreign  writers  on  similar  subjects,  by 


667790 


INTRODUCTION. 


several  of  whom  his  experiments  have  been  repeated  and 
the  results  confirmed,  shows  that  his  labours  are  extensively 
known  and  appreciated  on  the  continent  of  Europe. 

Sir  Humphrey  Davy  in  his  Lectures  on  the  Chemistry  of 
Agriculture,  and  Dr.  Lindley  in  his  Theory  of  Horticulture, 
together  with  many  other  writers  among  his  countrymen 
and  countrywomen,  have  by  the  adoption  of  his  opinions 
afforded  a  gratifying  proof  of  the  estimation  in  which  they 
hold  both  his  theoretic  views,  and  the  practical  results  lie 
deduced  from  them. 

A  taste  for  Horticulture  has  for  some  years  been  so 
universally  cultivated,  that  all  classes  are  familiar  ^with 
Mr.  Knight's  name  as  a  writer,  and  the  extracts  from  his 
papers  which  are  found  in  many  of  the  periodical  publica- 
tions on  Horticulture  and  Arboriculture  of  the  present  day, 
have  caused  the  readers  of  these  works  to  be  in  some  degree 
conversant  with  the  particular  subjects  on  which  he  has 
treated  ;  and  though  the  value  of  the  present  work  may  be 
diminished  by  the  task  of  editing  it  having  unavoidably  fallen 
to  those  who  are  ill  qualified  to  do  justice  to  the  undertaking, 
they  are  still  cheered  by  the  hope  that  their  imperfect 
attempt  may,  nevertheless,  by  making  both  Mr.  Knight's 
character  and  his  writings  better  known,  be  the  means  of 
demonstrating  more  fully  to  the  world  the  constant  and 
never-tiring  exertions  of  his  mind  in  the  pursuit  of  know- 
ledge, and  its  application  to  purposes  of  practical  utility 
for  the  benefit  of  his  fellow-creatures. 


INTRODUCTION.  Vll 


Mere  discoveries  in  abstract  science,  and  even  their  appli- 
cation to  an  increased  production  of  animal  and  vegetable 
food,  may  seem  to  the  casual  observer  not  entitled,  from  the 
want  of  dazzling  brilliancy,  to  more  than  secondary  importance 
and  fame ;  bnt  when  he  reflects  on  the  growth  of  crime  and 
the  insecurity  of  property  resulting  from  the  goading  and 
baneful  influence  of  the  male  suada  fames  on  a  population 
rapidly  outgrowing  its  means  of  existence,  he  will  then  allow 
that  such  labours  as  those  of  Mr.  Knight  are  likely  to  exercise 
a  most  beneficial  influence  on  the  moral  as  well  as  physical 
welfare  of  society. 

It  is  necessary  to  say  a  few  words  to  explain  why  a  work 
requiring  so  little  time  or  preparation  as  a  selection  of  papers, 
and  the  simple  sketch  of  Mr.  Knight's  life  prefixed  to  it,  should 
not  have  appeared  at  a  much  earlier  period  after  his  death. 
And  this  it  was  the  anxious  wish  of  his  family  should  have 
been  the  case.  They  were,  however,  induced  to  concede  their 
own  wishes  on  this  point  to  the  suggestions  of  a  gentleman 
who  had  kindly  undertaken  to  furnish  the  memoir,  and 
who  considered  that  the  materials  put  into  his  hands  were 
sufficient  to  form  a  more  pretending  volume. 

That  gentleman  having  very  lately  declined  to  proceed  with 
the  work  on  the  ground  of  ill  health,  the  original  design  has 
again  been  adopted,  and  the  very  few  letters  or  memorandums 
of  Mr.  Knight  that  remain  have  been  arranged  by  those 
unused  to  write  for  the  public  eye,  and  whose  judgment  may 
probably  be  biassed  by  the  devoted  respect  and  affection  they 


Vlll  INTRODUCTION. 

feel  for  the  memory  of  the  beloved  parent  whose  character 
they  have  attempted  to  portray. 

Under  such  circumstances,  it  is  hoped  this  unpretending 
memoir  will  be  received  with  indulgence. 

Mr.  Knight's  family  cannot  omit  this  opportunity  of 
acknowledging  with  thankfulness  how  much  they  owe  to 
GEORGE  BENTHAM,  Esq.,  for  the  kindness  which  has  led  him  to 
render  them  many  and  important  services  in  the  publication 
of  this  work :  and  to  Dr.  LINDLEY  they  are  also  indebted  for 
assistance  in  the  selection  of  the  papers  that  have  been 
deemed  most  desirable  for  the  present  volume.  Their  thanks 
are  also  due  to  the  Councils  of  the  Royal  and  Horticultural 
Societies  for  the  loan  of  the  copper-plates  illustrating  the 
papers  here  reprinted,  and  to  several  friends  of  Mr.  Knight 
for  communications  on  various  subjects. 

March,  1840.  ; 


CONTENTS. 


PAGE 

INTRODUCTION  ............      v 

LIFE  OF  THOMAS  ANDREW  KNIGHT,  ESQ.         ......  1 

PART  I. 

PAPERS  ON  VEGETABLE  PHYSIOLOGY.     READ  BEFORE  THE  ROYAL 

SOCIETY        ............     81 

I.  OBSERVATIONS  ON  THE  GRAFTING  OF  TREES.    Read  April  30,  1795      81 

II.  ACCOUNT  OF  SOME  EXPERIMENTS  ON  THE  ASCENT  OF  THE  SAP  IN 

TREES.      Read  May  14,  1801 84 

III.  ACCOUNT  OF  SOME  EXPERIMENTS  ON  THE  DESCENT  OF  THE  SAP  IN 

TREES.     Read  April  21,  1803 97 

IV.  EXPERIMENTS  AND  OBSERVATIONS  ON  THE  MOTION  OF  THE  SAP  IN 

TREES.     Read  February  16,  1804 105 

V.  CONCERNING   THE  STATE  IN  WHICH    THE  TRUE   SAP  OF  TREES  is 

DEPOSITED  DURING  WINTER.     Read  January  24,  1805  .      .  109 

VI.  ON  THE  REPRODUCTION  OF  BUDS.     Read  May  23,  1805       .  .  119 

VII.    ON    THE    DIRECTION    OF    THE    RADICLE    AND    GERMEN    DURING   THE 

VEGETATION  OF  SEEDS.  Read  January  9, 1806  .    .    .  .  124 

VIII.    ON    THE    INVERTED  ACTION  OF    THE  ALBURNOUS   VESSELS  OF  TREES. 

Read  May  15,  1806 ISO 

IX.  ON  THE  FORMATION  OF  THE  BARK  OF  TREES.     Read  February  19, 

1807 136 

X.    ON     THE     INCONVERTIBILITY     OF     BARK     INTO    ALBURNUM.        Read 

February  4,  1808 143 

XI.    ON    THE    ORIGIN  AND  OFFICE    OF  THE   ALBURNUM    OF  TREES.        Read 

June  30,  1808 148 

XII.  ON  THE  ORIGIN  AND  FORMATION  OF  ROOTS.     Read  February  23, 

1809 153 

v  XIII.    ON  THE  CAUSES  WHICH    INFLUENCE    THE  DIRECTION  OF  THE  GROWTH 

OF  ROOTS.     Read  March  7,  1811      ......  157 

XIV.  ON  THE  MOTIONS  OF  THE  TENDRILS  OF  PLANTS      Read  May  4,  1812  164 

XV.     ON    THE    ACTION  OF  DETACHED    LEAVES  OF  PLANTS.       Read  June  13, 

1816  .     .  168 


CONTENTS. 


PART   II. 


PAPERS  ON  PHYSIOLOGICAL  HORTICULTURE.     READ  BEFORE  THE 

HORTICULTURAL  SOCIETY   .........  172 

XVI.  OBSERVATIONS  ON  THE   MEANS   OP  PRODUCING   NEW   AND   EARLY 

FRUITS.     Read  November  4,  1806 172 

XVII.  DESCRIPTION  OF  A  FORCING-HOUSE   FOR  GRAPES,  WITH   OBSERVA- 
TIONS  ON    THE    BEST   MODE  OF  CONSTRUCTING   HOUSES   FOR   OTHER 

FRUITS.     Read  May  3,  1808 179 

XVIII.  ON  THE  MANAGEMENT  OF  THE  ONION.     Read  April  4, 1809      .     .  J81 

XIX.  ON  POTATOES.     Read  February  0,  1810 182 

XX.  ON  THE  CONSTRUCTION  OF  PEACH-HOUSES.     Read  April  3,  1810     .  186 

XXI.    A  CONCISE    VIEW  OF  THE    THEORY    RESPECTING    VEGETATION,  LATELY 
ADVANCED    IN    THE    PHILOSOPHICAL    TRANSACTIONS,   ILLUSTRATED 

IN  THE  CULTURE  OF  THE  MELON.  Read  January  2,  1811  .    .  189 

XXII.    ON      THE      ADVANTAGES      OF     EMPLOYING      VEGETABLE      MATTER      AS 

MANURE  IN  A  FRESH  STATE.     Read  January  6,  1812     .          .     .  193 

XXIII.  ON    FACILITATING     THE    EMISSION     OF    ROOTS    FROM    LAYERS.       Read 

February  4,  1812 195 

XXIV.  ON    THE    PREVENTION    OF    THE    DISEASE    CALLED    THE    CURL    IN    THE 

POTATOE.  Read  February  2, 1813 197 

XXV.    ON    THE    EARLY    PUBERTY    OF    THE    PEACH-TREE.         Read    March   2, 

1813 199 

XXVI.  ON  THE  CULTURE  OF  THE  PEAR-TREE.     Read  May  18,  1813  .  201 

XXVII.    ON    THE     PREVENTION    OF    MILDEW    IN     PARTICULAR    CASES.         Read 

May  4,  1813 204 

XXVIII.    ON    THE    CULTURE    OF    THE     SHALLOT,    AND    SOME    OTHER    BULBOUS- 
ROOTED  PLANTS.     Read  December  6,  1813         .  .          .          .209 

XXIX.    ON    THE    APPLICATION    OF    MANURE     IN    A     LIQUID    FORM    TO    PLANTS 

IN  POTS.     Read  May  17, 1814  .......  211 

XXX.    ON      THE      ILL    EFFECTS     OF     EXCESSIVE      HEAT     IN     FORCING-HOUSES 

DURING  THE  NIGHT.     Read  June  17,  1814        ....  213 

XXXI.    ON    THE     MODE     OF    PROPAGATION    OF    THE    LYCOPERDON    CANCELLA- 
TUM,  A    SPECIES   OF    FUNGUS,    WHICH    DESTROYS   THE    LEAVES    AND 

BRANCHES  OF  THE  PEAR-TREE.      Read  December  5, 1815          .     .  217 

XXXII.    ON    THE    EFFECTS    OF    DIFFERENT    KINDS    OF    STOCKS    IN    GRAFTING. 

Read  February  6,  1816 .221 

XXXIII.  ON  THE  VENTILATION  OF  FORCING-HOUSES.     Read  May  7, 1816      .     .224 

XXXIV.  UPON    THE    PROPER   MODE    OF    PRUNING    THE      PEACH-TREE,    IN    COLD 

AND  LATE  SITUATIONS.     Read  May  6,  1817       ....  226 
XXXV.  OBSERVATIONS    ON   THE    PROPER    MANAGEMENT   OF   FRUIT   TREES, 

WHICH     ARE    INTENDED     TO     BE      FORCED     VERY      EARLY     IN    THE 

ENSUING  SEASON.     Read  June  3,  1817  .          .         .          .     .  228 

XXXVI.    UPON    THE    PROPAGATION    OF    VARIETIES    OP    THE    WALNUT-TREE    BY 

BUDDING.     Read  April  7,  1818       .  .  231 


CONTENTS.  XI 

PAGE 

XXXVII.    UPON  THE    PRUNING    AND    MANAGEMENT  OF   TRANSPLANTED    STAND- 
ARD TREES.     Read  June  2, 1818 233 

XXXVIII.    UPON    THE    CULTURE    OF     THE     GUERNSEY    LILY.          Read    August    3, 

1819  .  .  .  .  .236 

XXXIX.    UPON    THE    EFFECTS     OF    VERY    HIGH    TEMPERATURE     ON    SOME    SPE- 
CIES OF  PLANTS.      Read  December  7,  1819  .  .      .  238 

XL.    UPON  THE  CULTURE    OF  THE    PINE-APPLE    WITHOUT    BARK   OR  OTHER 

HOTBED.      Read  March  7,  1820 242 

XLI.   PHYSIOLOGICAL  OBSERVATIONS  ON  THE  EFFECTS  OF  PARTIAL  DECOR- 

TICATION  OR  RINGING  THE    STEMS   OR  BRANCHES    OF  FRUIT-TREES. 

Read  June  6, 1820  . 246 

XLII.    UPON  THE  CULTURE   OF    THE    FIG-TREE    IN    THE    STOVE.        Read  July 

18,  1820 248 

XLI II.  ON  THE  CULTURE  OF  THE  COCKSCOMB.     Read  December  19, 1820     .  250 
XLIV.  OBSERVATIONS  ON  HYBRIDS.     Read  February  6,  1821         .          .     .  251 

XLV.  UPON  THE  MANAGEMENT  OF  FRUIT-TREES  IN  POTS.      Read  May  8, 

1821 254 

XLVI.  ACCOUNT  OF  AN  IMPROVED  METHOD    OF  RAISING  EARLY  POTATOES 

IN  THE  OPEN  GROUND.     Read  June  5,  1821  .          .          .        256 

XLVI  I.  ON  GRAFTING  THE  VINE.     Read  September  18,  1821     .          .          .  258 

XLVIII.   FURTHER    OBSERVATIONS    ON    THE    CULTIVATION    OF    THE    PINE- 
APPLE.    Read  March  5,  1822 260 

XLIX.  DESCRIPTION  OF  A  MELON  AND  PINE  PIT.       Read  July  16,  1822  .  261 

L.    UPON     THE    ADVANTAGES     AND     DISADVANTAGES     OF      CURVILINEAR 

IRON  ROOFS  TO  HOTHOUSES.     Read  October  1,  1822     .          .          .  263 

LI.  A  NEW  AND  IMPROVED   METHOD   OF  CULTIVATING  THE   MELON. 

Read  November  15,  1822 267 

LI  I.  ACCOUNT  OF  THE  INJURIOUS  INFLUENCE  OF  THE  PLUM  STOCK  UPON 

THE  MOORPARK  APRICOT.     Read  April  1,  1823  .          .          .272 

LIU.  ACCOUNT  OF  SOME  MULE  PLANTS.     Read  May  6,  1823        .          .     .  275 

LIV.  REMARKS  ON  THE  SUPPOSED  INFLUENCE  OF  THE  POLLEN  IN  CROSS- 
BREEDING, UPON   THE   COLOUR   OF     THE    SEED-COATS    OF    PLANTS, 

AND  THE  QUALITIES  OF  THEIR  FRUITS.     Read  June  3,  1823       .  278 

LV.  ON  THE  PREPARATION   OF   STRAWBERRY   PLANTS   FOR   EARLY 

FORCING.     Read  March  16,  1824 280 

LVI.  ON  THE  CULTIVATION  OF  STRAWBERRIES.     Read  December  21, 1824  283 

LVII.    UPON      THE     BENEFICIAL      EFFECTS    OF     PROTECTING     THE    STEMS    OF 

FRUIT-TREES  FROM  FROST  IN  EARLY  SPRING.     Read  February  1, 
1825 286 

LVIII.  ACCOUNT  OF  A  METHOD  OF  OBTAINING  VERY  EARLY  CROPS  OF  THE 

GRAPE  AND  FIG.     Read  March  1,  1825     .....  288 
LIX.  ON  THE  CULTURE  OF  THE  STRAWBERRY.       Read  May  17,  1825      .  290 

LX.    ON  THE  CULTIVATION    OF  THE  AMARYLLIS  SARNIENSIS,  OR  GUERNSEY 

LILY.      Read  December  20,  1825 292 

LXI.  UPON  THE  CULTURE  OF  CELERY.     Read  December  5,  1826        .     .  294 

LXII.    UPON    THE    CULTURE    OF  THE    PRUNUS    PSEUDOCERASUS,    OR    CHINESE 

CHERRY.     Read  February  20,  1827 295 


Xll  CONTENTS. 

r-A(;K 

LXIII.    ACCOUNT    OF    SOME    IMPROVEMENTS    IN    THE    CONSTRUCTION      OP    HOT- 
BEDS.    Read  July  3,  1827 298 

LXIV.  ON  THE  CULTURE  OF  THE  POTATO.       Read  July  1,  1828       .          .  300 
LXV.  ON  THE  CULTIVATION  OF  THE  PINE-APPLE.     Read  August  19, 1828  302 

LXVI.    UPON    THE     SUPPOSED     CHANGES     OF      THE      CLIMATE      OF     ENGLAND. 

Read  May  5,  1829 307 

LXV1I.  ACCOUNT  OF  AN  ECONOMICAL  METHOD  OF  OBTAINING  VERY  EARLY 

CROPS  OF  NEW  POTATOES.      Read  May  4,  1830          .          .          .  310 
LXVI  1 1.  ACCOUNT    OF    A   METHOD  OF  OBTAINING    VERY    EARLY    CROPS  OF 

GREEN  PEAS.     Read  May  18,  1830    .          .          .          .  .  312 

LXIX.    UPON     THE     CULTIVATION      OF    THE      PERSIAN      VARIETIES     OF      THE 

MELON.    Read  May  1,  1831 314 

LXX.  ON  THE  POTATO.     Read  February  1,  1831 318 

LXXI.    ON     THE     MEANS     OF      PROLONGING     THE     DURATION    OF     VALUABLE 

VARIETIES  OF  FRUITS.     Read  May  3,  1831       ....  323 
LXX1I.  UPON  GRAFTING  THE  WALNUT-TREE.     Read  April  17,  1832        .     .  326 

LXXI1I.    ON    THE     BENEFICIAL     EFFECTS     OF     THE    ACCUMULATION    OF    SAP    IN 

ANNUAL  PLANTS.      Read  December  20,  1830     ....  328 

LXXIV.    ON    THE  ADVANTAGES   OF    IRRIGATING     GARDEN    GROUNDS    BY  MEANS 

OF  TANKS  OR  PONDS.     Read  August  7,  1832        .          .          .        332 
LXXV.  ON  THE  CULTURE  OF  THE  POTATO.     Read  March  19,  1833  .  334 

LXXVI.   UPON    THE    CAUSES    OF    THE    PREMATURE    DEATH    OF    PARTS    OF     THE 
BRANCHES    OF  THE    MOORPARK    APRICOT,  AND    SOME    OTHER    WALL 

FRUIT-TREES.     Read  June  2,  1835      .          .          .          .          .     .  336 

LXXVII.    ON     THE      MEANS     EMPLOYED      IN    RAISING    A    TREE      OF      THE    IMPE- 

RATRICE  NECTARINE.     Read  February  3,  1835         .          .          .  330 

LXXVII  I.   ON       THE        PROPAGATION      OF     TREES       BY      CUTTINGS     IN      SUMMER. 

Read  April  3,  1838 340 


APPENDIX. 

CONTAINING  PAPERS  ON  ANIMAL  ECONOMY.     READ  BEFORE  THE 
ROYAL  SOCIETY  : — 

I.    ON  THE    COMPARATIVE    INFLUENCE  OF    MALE    AND    FEMALE    PARENTS 

ON  THEIR  OFFSPRING.    Read  June  22,  1819          .         .          .     .  343 
II.  ON  THE  ECONOMY  OF  BEES.     Read  May  14,  1807  .          .          .  348 

III.  ON    SOME    CIRCUMSTANCES     RELATING     TO      THE       ECONOMY    OF    BEES. 

Read  May  22,  1838 354 

IV.  ON  THE    HEREDITARY  INSTINCTIVE  PROPENSITIES  OF  ANIMALS.       Read 

May  25,  1837 358 


LIFE 


THOMAS   ANDREW   KNIGHT, 


OF  the  early  history  of  the  family  from  which  Mr.  Andrew 
Knight  is  descended  but  little  is  known  with  certainty.  The 
records  of  Shrewsbury  show  that,  from  the  reign  of  Henry  VI. 
to  that  of  Charles  I.,  a  family  of  the  name  of  Knight  resided 
in  that  town,  and  repeatedly  filled  its  civic  offices ;  and  one  of 
them,  Thomas  Knight,  in  1509,  was  elected  one  of  its  represen- 
tatives in  parliament.  A  pedigree  of  the  Shrewsbury  knights  is 
preserved  in  the  British  Museum,  with  arms  identical  with  those 
used  by  the  present  family  :  and  the  Christian  names  borne  by 
both  bear  a  striking  similarity.  The  name  disappears  from  the 
Shrewsbury  annals  just  at  the  time  when  Mr.  Richard  Knight, 
the  great  grandfather  of  the  subject  of  this  memoir,  is  known  to 
have  been  residing  on  an  estate  of  his  own  at  Castle  Green  in 
the  parish  of  Madeley,  in  the  same  county ;  and  when  it  is 
recollected  with  what  irregularity  parish  registers  were  kept 
during  the  civil  wars,  it  is  not  surprising  that  the  connecting 
link  should  not  have  been  more  exactly  traced. 

Mr.  Richard  Knight's  eldest  son,  Francis,  was  born  at  Castle 
Green  in  1640,  where  he  succeeded  his  father  and  resided  till 
his  death.  The  second  son,  Richard,  was  born  in  1658,  and 
attained  to  considerable  eminence  in  his  day,  from  the  success 
which  attended  his  mercantile  speculations,  and  the  high  cha- 
racter he  established  for  independence  and  probity ;  and  he 
deserves  more  especial  notice  here  as  the  founder  of  the  fortune 
of  his  family. 

B 

•7 


LIFE    OF 


He  early  embarked  in  the  iron  trade,  and  worked  a  forge,  the 
remains  of  which  are  still  to  be  seen  at  the  lower  end  of  Coal- 
brooke  Dale.  This  district  was  not  at  that  period,  as  it  is  now, 
the  great  field  of  the  iron  trade  of  Shropshire,  and  he  soon 
quitted  it  for  a  forge  at  Moreton,  in  the  parish  of  Shawbury. 

The  smelting  of  iron  at  this  time  was  carried  on  almost  uni- 
versally by  means  of  wood  charcoal  in  small  furnaces,  the 
;  bello>vst  {XrtwJiich  were  worked  by  water-wheels,  and  were  gene 
j-ally  situated  one  the  banks  of  streams,  in  the  vicinity  of  large 
'tracts  b'f  coppice  wood.  The  scale  on  which  these  works  were 
carried  on,  as  compared  with  those  of  the  present  day,  may  best 
be  understood  by  the  fact  that,  in  1740,  a  few  years  before 
Mr.  Richard  Knight's  death,  there  were  only  fifty-nine  iron 
furnaces  in  the  whole  of  England  and  Wales  *,  and  the  average 
quantity  of  metal  produced  by  each  was  5  tons  13  cwt.  per 
week ;  while  in  Shropshire  alone  there  were  lately  between  fifty 
and  sixty  furnaces  at  work,  each  producing  above  seventy  tons 
per  week~f~ !  In  1740  there  were  only  six  furnaces  in  Shrop- 
shire, which  together  made  two  thousand  tons  per  annum  :  of 
these  Mr.  Richard  Knight  had  two,  besides  several  forges ;  he 
had  also  one  forge  in  Staffordshire,  and  shares  in  nearly  the 
whole  of  the  iron  works  of  Worcestershire,  and  a  furnace  and 
forge  at  Bringewood  near  Ludlow,  in  Herefordshire. 

Long  before  this  time  the  manufacture  of  iron  had  begun  to 
decline  J,  owing  to  the  increasing  difficulty  of  procuring  an 
adequate  supply  of  fuel ;  which  is  not  surprising,  when  it  is 
known  that  a  large  furnace  will  consume  in  a  year  the  produce 
of  one  hundred  and  twenty  acres  of  coppice  wood !  The  trade 

*  See  Art.  on  Iron  making  in  Supp.  to  Encyclop.  Brit. 

t  Paper  read  at  meeting  of  the  Shropshire  Nat.  Hist.  Soc.  by  Mr.  T.  Blunt. 

J  Dudley,  who  wrote  in  the  reign  of  James  I.  states  that  there  were  at  that 
time  in  England  three  hundred  furnaces  for  the  manufacture  of  pig-iron,  making 
the  astonishing  quantity  annually  of  one  hundred  and  eighty  thousand  tons, 
though  he  says  "  the  trade  is  falling  into  decaye." — See  Supp.  to  Encyclop.  Brit. 
— A  curious  old  pamphlet,  without  date,  but  written  since  1714,  "  On  the 
Interest  of  Great  Britain  in  supplying  Herself  with  Iron,"  gives  the  whole 
quantity  then  made  as  12,190  tons,  and  states  that  it  had  been  19,485  tons. 


THOMAS    ANDREW    KNIGHT,    ESQ.  3 

did  not  begin  to  revive  till  about  1750,  when  tbe  use  of  pit 
coal*  in  blast  furnaces  became  general.  It  seems,  therefore, 
probable  that  Mr.  Knight  owed  his  extraordinary  success  solely 
to  the  efforts  of  his  own  powerful  mind  and  the  enlarged  views 
by  which  his  proceedings  were  directed,  for  it  was  evidently  not 
during  the  prosperous  days  of  the  iron  trade  that  he  made  his 
fortune,  nor  is  it  supposed  that  his  original  capital  was  at  all 
considerable. 

After  he  became  a  rich  man,  he  never  departed  from  the  sim- 
plicity of  his  early  habits.  One  of  his  few  indulgences  was  that 
of  riding  a  fine  horse :  and  this,  perhaps,  may  have  been  as  much 
dictated  by  prudence  as  pleasure,  for  before  the  establishment 
of  country  banks  large  sums  of  money  were  necessarily  trans- 
ferred from  place  to  place  on  horseback.  One  undoubted 
deviation  from  the  unostentatious  mode  of  living  attributed  to 
him  has  been  handed  down,  in  a  magnificent  silver  punch-bowl, 
capable  of  containing  nine  quarts,  with  the  contents  of  which  it 
was  his  custom  to  regale  himself  and  his  friends.  Many 
anecdotes  are  told  of  this  old  gentleman,  which,  after  all  due 
allowance  has  been  made  for  the  change  of  manners  that  the 
lapse  of  two  centuries  has  made,  still  show  that  he  must  have 
been  a  person  of  very  singular  habits. 

On  one  occasion  a  large  quantity  of  Russian  iron  was  adver- 
tised for  sale  at  a  certain  inn  in  the  city,  and  on  the  day 
appointed,  Mr.  Knight  arrived  there  meanly  dressed  ;  and  while 
waiting  for  the  sale  to  commence,  he  volunteered  his  assistance 
to  relieve  a  man  who  was  employed  in  turning  a  spit  on  which 
a  piece  of  beef  was  roasting.  While  so  employed,  he  entered 
into  conversation  with  the  landlord,  who  told  him  that  a  great 

*  Fuller,  in  his  "Worthies  of  England,"  printed  in  1662,  indulges  in  the 
following  amusing  anticipations  on  this  subject : — "  What  we  may  call  river  or 
fresh-water  coals,  digged  out  in  this  county  (Shropshire),  at  such  a  distance 
from  Severn  that  they  are  easily  ported  by  boat  into  other  countries.  Oh  ! 
if  this  coal  could  be  so  charked  as  to  make  iron  melt  out  of  the  stone,  as  it 
maketh  it  in  smiths'  forges,  to  be  wrought  in  the  bars  !  But  Rome  was  not 
built  in  a  day ;  and  a  new  world  of  experiments  is  lefte  to  the  discoverie  of 
posteritic." 

B    2 


LIFE    OF 


iron-master  from  Shropshire,  of  the  name  of  Knight,  was,  with 
many  others,  expected  to  be  present  at  the  sale.  He  remained 
incognito,  and  in  the  back  ground,  till  the  sale  was  nearly 
over,  yet  he  managed  to  become  the  successful  competitor ;  but 
from  his  shabby  appearance  the  auctioneer  hesitated  to  accept 
him,  from  a  doubt  of  his  responsibility  to  pay  the  amount. 
The  sum  which  he  cleared  by  this  transaction  is  said  to  have 
been  extremely  large. 

At  another  time,  he  lost  his  way  in  the  dark  on  a  common  near 
Stourbridge,  when  he  was  conveying  a  very  large  sum  of  money 
in  his  saddle-bags,  and  he  was  at  length  himself  admitted  into 
the  cottage  of  a  collier,  and  his  horse  and  bags,  which  he  said 
were  filled  with  nails,  were  placed  in  an  adjoining  shed.  A 
we'dding  feast,  which  is  always  an  occasion  of  much  more 
gaiety  among  colliers  than  it  is  with  agricultural  labourers,  was 
bein^  celebrated  in  the  cottage,  when  Mr.  Knight  joined  the 
party,  and  danced  in  his  boots,  till  the  return  of  daylight 
enabled  him  to  proceed  on  his  journey.  At  parting  he  pre- 
pared to  present  a  gratuity  to  his  host  for  his  entertainment, 
but  it  was  declined  on  the  ground  that  nothing  was  expected 
from  so  poor  a  man.  He  then  made  himself  known,  and  pre- 
sented the  collier  with  five  guineas. 

Mr.  Richard  Knight  removed  to  Bringewood  Forge  about  the 
year  1698,  of  which  he  had  taken  a  lease  for  twenty-one  years 
from  the  second  Lord  Craven,  and  on  the  improvement  of  which 
he  immediately  expended  between  £20,000  and  £30,000.  Lord 
Craven's  predecessor  had,  about  thirty  years  before,  purchased 
an  extensive  tract  of  land,  including  the  forest  of  Mocktree  and 
the  chase  of  Bringewood,  from  the  Earl  of  Lindsey,  to  whose 
father,  the  first  earl,  it  had  been  granted  by  Charles  L*  in 
reward  for  the  services  Lord  Lindsey  had  rendered  to  the  Royal 
cause  during  the  struggle  between  the  king  and  the  parliament. 

*  In  a  paper,  No.  354  of  the  Harl.  MSS.  in  the  British  Museum,  is  a  survey 
of  the  forests  and  chases  of  Mocktree  and  Bringewood,  made  in  the  reign  of 
James  I.  from  which  the  following  is  an  extract :  "  These  forests  are  stately 
grounds,  and  do  breed  a  great  and  large  deer,  and  will  keep  of  red  and  fallow 


THOMAS    ANDREW    KNIGHT,    ESQ.  5 

Before  the  expiration  of  the  lease,  Mr.  Knight  had  himself 
become  the  possessor  of  this  portion  of  Lord  Craven's  estate, 
together  with  much  other  land  adjoining,  on  part  of  which  his 
grandson,  Mr.  Payne  Knight,  between  the  years  1773  and  1776, 
built  the  mansion  of  Downton  Castle. 

Previously  to  Mr.  Knight's  removal  to  Bringewood,  he  had 
married  the  daughter  of  Mr.  Andrew  Payne  of  Shawbury,  and 
two  sons  had  been  born.  The  eldest,  Richard,  afterwards  mar- 
ried Miss  Powell  of  Stanage  Park,  county  Radnor,  and  had 
a  daughter,  who  became  the  wife  of  Thomas  Johnes,  Esq.,  of 
Havod,  county  Cardigan,  and  was  mother  to  Colonel  Johnes 
and  the  Rev.  Samuel  Johnes  Knight. 

From  her  the  Johneses  inherited  Croft  Castle,  in  Hereford- 
shire, Stanage  Park,  and  the  Priory,  near  Cardigan. 

Of  the  second  son,  Thomas,  more  will  be  said  hereafter. 
There  were  also  two  younger  sons,  Edward  and  Ralph,  who 
were  ancestors  of  those  branches  of  the  family  who  settled  at 
Wolverley,  in  Worcestershire,  and  Henley  Hall,  in  Shropshire. 
Mr.  Knight  had  several  daughters,  from  one  of  whom  is 
descended  Mr.  Samuel  Rogers,  the  distinguished  author  of  "  The 
Pleasures  of  Memory  ;"  and  another  married  Mr.  —  Spooner,  of 
Warwickshire,  and  was  the  mother  of  the  last  race  of  that 
name. 

Mr.  Richard  Knight  died  at  his  house  at  Downton,  February 
3rd,  1745,  and  was  buried  in  the  chancel  of  Burrington  church, 
under  an  appropriate  monument — a  large  slab  of  cast  iron  ! 

Mr.  Thomas  Knight  was  born  in  the  year  1 700,  and  entered 
the  Church.  In  1730  he  was  presented  by  the  Lord  Herbert  to 
the  livings  of  Ribbesford  and  Bewdley,  in  the  county  of  Wor- 

deer  two  or  three  thousand  at  least.  Mem.  That  the  forest  and  chase  of 
Mocktree  and  Bringewood  are  near  adjoining  to  the  castle  of  Ludlow,  the  chief 
house  of  the  Prince  of  Wales,  out  of  which  the  President  and  Council  had  their 
timber  for  building,  and  wood  and  coals  for  their  provisions,  besides  the  pleasures 
of  the  game,  till  they  were  granted  to  Robert,  Earl  of  Essex  (by  Queen 
Elizabeth),  since  when  the  ^ord  President  and  Council  have  been  enforced  to 
buy  their  timber,  wood,  and  coals,  which  was  a  great  charge  to  her  Majesty, 
and  is  likely  to  be  so  to  his  Majesty." 


6  LIFE    OF 

cester,  which  he  held  till  his  death  ;  though,  after  his  marriage, 
he  resided  at  Wormesley  Grange,  near  Hereford.  He  was  a 
man  of  great  simplicity  and  kindness  of  character,  combined 
with  superior  ability,  and  his  views  on  many  subjects  appear  to 
have  been  in  advance  of  the  period  in  which  he  lived  ;  he  was 
greatly  beloved  and  respected  by  his  neighbours,  by  whom  his 
remarks  and  axioms  were  long  remembered,  and  quoted  to  his 
children. 

He  died  November  3rd,  1764,  and  was  interred  at  Wormesley. 
He  left  two  sons  and  two  daughters  :  the  eldest,  Mr.  Payne 
Knight,  was  born  February  3rd,  1/50  ;  Thomas  Andrew,  the 
youngest  son,  was  born  at  Wormesley  Grange  on  the  12th  of 
August,  1 759,  and  was  therefore  only  five  years  old  at  the  period 
of  his  father's  death. 

The  early  education  of  both  these  brothers  was  much  neg- 
lected, particularly  that  of  the  eldest,  who  never  was  at  a  public 
school,  or  at  either  of  the  Universities ;  and  the  eminence  to 
which  he  attained  as  a  scholar,  adds  another  to  the  many 
instances  on  record,  of  the  manner  in  which  an  energetic  mind 
will  press  forward  in  pursuit  of  knowledge  in  spite  of  disadvan- 
tages and  difficulties.  Mr.  Payne  Knight  did  not  begin  the 
study  of  the  Greek  language  till  he  was  eighteen,  and  his  atten- 
tion was  then  chiefly  directed  to  those  subjects  which  illustrate 
Greek  'sculptures  and  coins,  viz.,  Mythology  and  the  Archaic 
Greek  language,  and  the  earliest  productions  of  his  pen  were 
devoted  to  elucidate  some  obscure  points  of  Greek  mythology. 
He  visited  Italy  before  he  was  of  age,  and  there  acquired  that 
taste  for  the  fine  arts,  and  especially  for  the  productions  of  the 
Greek  sculptor,  which  led  to  his  forming  the  magnificent  col- 
lection of  ancient  bronzes  and  coins  bequeathed  by  his  will  to 
the  British  Museum*.  The  only  one  of  Mr.  P.  Knight's 
works  which  has  much  interest  for  the  general  reader  is  "  An 
Analytical  Inquiry  into  the  Principles  of  Taste,"  first  published 
in  1805.  and  which  has  passed  through  several  editions.  In 
1809  the  Dilettanti  Society  published  a  splendid  work  entitled 

*  The  value  of  this  collection  was  estimated  at  50,000^. 


ESQ.  7 

"  Specimens  of  Ancient  Sculpture  selected  from  different  collec- 
tions in  Great  Britain/'  the  subjects  for  which  were  chosen  by  Mr. 
P.  Knight,  and  he  wrote  the  preface  and  the  description  of  the 
plates.  He  was  also  the  author  of  several  poems  :  "  The  Land- 
scape," "  Progress  of  Civil  Society,"  "  Monody  of  the  Death  of 
Mr.  Fox,"  and  "  Alfred,  a  Romance  in  Rhyme,"  and  of  some 
articles  in  the  Edinburgh  Review.  In  1820,  he  published  an 
edition  of  the  Iliad  and  Odyssey.  His  object  in  this  edition 
was  to  restore  the  text  of  Homer  to  its  original  state.  His 
"  Inquiry  into  the  Principles  of  Taste  "  was  reviewed  in  the 
"Edinburgh  Review"  for  January  1806.  Mr.  P.  Knight  was 
elected  to  serve  in  parliament  for  the  borough  of  Leominster 
in  1780 ;  and  in  1784  he  was  chosen  one  of  the  representatives 
of  Ludlow,  for  which  place  he  continued  to  sit  until  1 806,  when 
he  retired  from  parliament. 

Mr.  Andrew  Knight  received  his  early  education  at  Ludlow, 
from  whence  he  was  removed  to  a  school  of  considerable  reputa- 
tion at  Chiswick,  then  kept  by  Dr.  Crawford.  He  was  afterwards 
entered  of  Baliol  College,  Oxford,  where  the  late  eminent 
physician  Dr.  Baillie  was  his  contemporary  :  who  used  to  say  of 
him,  "  that  he  managed  to  acquire  as  much  Latin  and  Greek 
as  most  of  his  fellow-students,  though  he  spent  less  time  about 
it,  and  much  less  than  he  devoted  to  field  sports."  He  was  at 
this  period  and  continued  for  many  years  afterwards  to  be  an 
eager  sportsman,  and  an  excellent  shot ;  but  with  him,  even  in 
his  boyhood,  killing  the  game  was  only  a  secondary  consideration 
to  the  opportunities  which  his  long  rambles  with  his  gun  afforded 
him  for  studying  nature  ;  and  from  the  facts  and  incidents 
collected  at  this  early  period  he  laid  in  a  fund  of  information 
which  formed  the  basis  of  many  of  his  subsequent  investi- 
gations. 

He  was  at  this  time  painfully  shy,  and  it  was  difficult  to  draw 
him  out ;  but  he  was  remarkable  for  the  steadiness  with  which 
he  resisted  all  attempts,  whether  by  persuasion  or  raillery, 
to  join  in  the  intemperate  habits  then  so  common  in  the 
Universities. 


8  LIFE    OF 

His  school  holidays,  and  afterwards  his  college  vacations, 
were  spent  either  with  his  brother  in  London  or  with  his 
mother,  who  had  continued  to  reside  at  Wormesley  Grange  for 
some  years  after  her  husband's  death  ;  but  having  sustained  the 
loss  of  both  her  daughters  (one  in  her  16th,  the  other  in  her 
19th  year),  she  removed  to  Maryknowle,  a  small  house  near 
Ludlow,  which  Mr.  Payne  Knight  had  fitted  up  as  a  temporary 
residence  for  himself  during  the  time  he  was  building  Downton 
Castle.  Some  account  of  Mr.  Andrew  Knight's  occupations  and 
pursuits  at  this  period  has  been  furnished  by  the  pen  of  his 
early  friend  the  late  Dean  of  Exeter,  Dr.  Landon.  The  inter- 
course of  which  the  commencement  is  here  described  was 
continued  till  Mr.  Knight's  death,  which  was  followed,  after  the 
lapse  of  only  a  few  months,  by  that  of  the  dean. 

"  My  acquaintance  with  Mr.  Thomas  Andrew  Knight  com- 
menced at  Oxford,  when  he  was  a  member  of  Baliol  College,  in 
1778  or  1779?  I  cannot  name  the  exact  time.  When  at  college 
in  our  leisure  hours  we  often  met,  and  frequently  took  walks 
together.  Close  application  was  not  one  among  the  character- 
istics of  his  college  life.  A  little  reading,  with  his  extraordinary 
memory  and  great  natural  talents,  went  very  far  in  improving 
the  powers  of  his  mind.  His  classical  reading  in  Greek  and 
Latin  was  not  extensive,  but  whatever  he  once  gave  his  mind 
to  made  impressions  which  he  never  lost.  One  line  in  Virgil, 
particularly  of  the  Georgics,  if  quoted  in  our  familiar  conversa- 
tion, would  generally  be  followed  by  a  recital  of  pages  ;  and  the 
same  faculty  eminently  displayed  itself  if  an  accidental  reference 
were  made  to  Milton's  Paradise  Lost,  or  Thomson's  Seasons, 
when  the  mention  of  a  single  passage  would  draw  from  him  an 
accurate  repetition  of  a  whole  book,  with  scarcely  a  pause  for 
recollection.  In  vacations  from  the  University  I  frequently 
visited  him  when  he  resided  with  his  aged  mother  at  Mary- 
knowle ;  and  his  filial  attention  to  the  comfort  and  domestic 
happiness  of  that  most  excellent  old  lady  it  was  always  delight- 
ful to  witness,  and  most  strikingly  evinced  an  affectionate  and 
amiable  disposition  of  heart.  When  amusements  were  not  to  be 


THOMAS    ANDREW    KNIGHT,    ESQ.  9 

sought  out  of  doors,  we  were  by  no  means  idle  on  a  rainy  day  ; 
and  the  manufacture  of  tackle  for  a  day's  fishing  did  not 
altogether  preclude  attention  from  subjects  of  a  more  important 
nature.  In  the  evenings  a  desultory  discussion  on  philosophical 
topics,  on  which  neither  of  us  were  very  deeply  informed, 
served  at  least  to  awaken  an  inclination  to  be  better  acquainted 
with  them  ;  and  in  those  early  days  inquiry  was  first  made  as  to 
the  authors  who  could  best  throw  light  upon  mineralogy, 
chemistry,  botany,  agriculture,  and  the  various  branches  of 
natural  and  experimental  philosophy.  The  flame  once  kindled, 
excited  great  ardour  in  the  pursuit  of  intelligence  upon  most  of 
these  sciences ;  and  the  quickness  of  perception  and  comprehen- 
sion which  marked  the  course  of  my  friend's  investigations  soon 
outran  the  ordinary  course  of  study,  and  led  him  to  commence 
a  course  of  discoveries  upon  intricate  and  novel  subjects  on 
which  his  precursors  had  rarely  bestowed  a  passing  thought." 

Mr.  Knight's  mind,,  from  the  earliest  dawn  of  his  under- 
standing, seemed  peculiarly  formed  for  the  enjoyment  of  a 
country  life ;  and  the  part  of  England  on  which  his  lot  had 
fallen,  was  eminently  calculated  to  draw  forth  and  exercise  the 
latent  faculties  of  his  mind.  Its  hills,  its  valleys,  its  rivers,  its 
vegetable  productions,  its  geological  structure,  and  its  meteoro- 
logical changes,  were  to  him  objects  of  philosophical  investi- 
gation ;  while  the  study  of  what  Goldsmith  so  well  denominates 
"  Animal  Biography,"  afforded  him  constant  delight  and 
amusement. 

In  this  manner  Mr.  Knight  passed  some  years,  occasionally 
quitting  his  favourite  pursuits  to  visit  his  brother  in  London, 
at  whose  house  he  never  failed  to  meet  a  society  calculated 
to  exert  the  most  beneficial  influence  on  his  mind  and 
manners. 

In  1790  he  accompanied  his  brother,  and  his  friend'  Mr. 
Townley,  to  Paris ;  but  the  symptoms  of  the  approaching 
Revolution  were  becoming  so  fearfully  manifest,  that  at  the  end 
of  six  weeks  they  returned  to  London,  and  Mr.  Andrew  Knight 
never  again  quitted  England. 


10  LIFE    OF 

The  following  year  Mr.  Knight  married  Frances,  the  youngest 
daughter  of  the  late  Humphrey  Felton,  Esq.,  of  Woodhall,  near 
Shrewsbury.  The  gentleness  of  her  disposition  and  her 
unceasing  endeavours  to  promote  his  comfort  and  happiness 
during  the  forty-six  years  they  were  permitted  to  spend 
together,  secured  to  her  the  affections  of  a  heart  so  calculated 
for  the  reception  of  the  endearing  ties  of  domestic  life,,  as  that 
of  Mr.  Knight ;  and  the  pain  of  separation  is  now  softened  to 
her  by  a  recollection  of  the  uninterrupted  harmony  in  which  this 
long  interval  was  passed. 

On  his  marriage,  Mr.  Knight  established  himself  at  Elton,  in 
the  immediate  vicinity  of  his  mother's  and  brother's  residences  ; 
the  acquisition  of  a  hothouse  and  a  farm  now  enabled  him  to 
prosecute  his  experiments  in  horticulture  and  agriculture  with 
more  advantage  than  heretofore.  His  income,  as  a  younger 
brother,  was  at  this  time  limited,  and  it  was  astonishing  how 
much  he  did  to  advance  the  science  of  horticulture  with  a 
garden  and  an  establishment  of  the  least  expensive  description  ; 
but  one  of  his  peculiarities  was,  the  readiness  by  which,  with  his 
own  hands  and  the  assistance  of  a  common  carpenter  or  black- 
smith, he  would  construct  all  the  machinery  he  required  for 
conducting  his  most  elaborate  experiments. 

About  this  time  Mr.  Knight  became  acquainted  with  Sir 
Joseph  Banks ;  and  this  introduction  had  so  important  an 
influence  on  his  future  proceedings,  that  it  should  not  pass 
unnoticed.  It  occurred  in  the  following  manner : — The  Board 
of  Agriculture  had  drawn  up  a  set  of  queries,  to  which  they 
desired  to  obtain  answers  from  different  districts ;  and  an 
application  had  been  made  to  Sir  Joseph  Banks  to  recommend 
persons  properly  qualified,  to  whom  the  queries  should  be 
addressed.  Sir  Joseph  referred  to  Mr.  Payne  Knight  to 
recommend  some  one  for  this  purpose  in  Herefordshire ;  who 
mentioned  his  brother,  as  more  likely  than  any  one  he  knew  to 
fulfil  the  object  in  view,  from  his  practical  knowledge  of  the 
agricultural  operations  of  that  part  of  England,  as  well  as  from 
the  attention  he  had  given  to  its  natural  history. 


THOMAS    ANDREW    KNIGHT,,    ESQ.  11 

Mr.  Andrew  Knight  was  accordingly  made  known  to  Sir 
Joseph^  who  soon  found  that  he  was  not  only  eminently 
qualified  to  effect  the  immediate  object  in  view,  but  that  he  had 
made  observations,  and  deduced  theories  from  them,  calculated 
to  throw  much  light  on  the  more  abstruse  subject  of  vegetable 
physiology ;  and  he  strongly  urged  him  to  lay  the  result  of  his 
researches  before  the  public.  Mr.  Knight  had  not  mixed  a 
great  deal  jn  general  society  ;  he  had  not  had  access  to  many 
modern  scientific  works,  and  his  information  had  been  almost 
wholly  derived  from  the  study  of  nature  ;  and  it  was  not  until  he 
was,  by  Sir  Joseph  Banks,  brought  into  contact  with  many  of  the 
most  distinguished  men  in  science  and  literature,  who  assem- 
bled at  the  evening  converzatione  in  Soho  Square,  that  he  was 
himself  aware  that  he  had  observed  anything  which  had  escaped 
the  scrutiny  of  other  naturalists. 

In  Sir  Joseph,  Mr.  Knight  had  a  friend  always  anxious  to 
draw  him  forth,  and  zealously  alive  to  his  success ;  ever  ready 
to  obtain  information  for  him  on  any  subject,  or  to  give  his 
advice  and  assistance  ;  and  his  suggestions  were  always  received 
with  the  consideration  they  deserved  and  acknowledged  with 
gratitude.  At  Sir  Joseph's  house  he  had  occasionally  oppor- 
tunities of  comparing  his  own  observations  and  theories 
with  those  of  many  of  the  most  celebrated  naturalists  of  all 
countries ;  and  it  would  probably  have  been  advantageous  to 
him  had  those  interchanges  of  information  and  opportunities 
for  discussion  been  more  frequent,  for  it  would  have  saved  him 
trouble  in  working  out  facts  which  cost  all  the  labour  and  time 
of  original  discoveries,  and  which  labour  would  have  been  more 
profitably  employed  in  building  on  the  sub-structure  already 
laid  by  other  hands.  He  for  some  years  purposely  avoided 
to  read  the  works  of  his  precursors  in  the  field  of  vegetable 
physiology,  from  an  idea  that,  by  the  study  of  nature,  unbiassed 
by  the  opinions  of  others,  he  should  be  most  likely  to  arrive  at 
truth  ;  but  he  was  at  length  induced  to  deviate  from  this  course 
by  the  advice  of  his  friend  Sir  Joseph. 

In  the  latter  years  of  Mr.  Knight's  life,  age  and  other  causes 


12  LIFE    OF 

had  conspired  to  make  him  less  and  less  inclined  to  enter  into 
general  society,  and  he  saw  little  of  any  one  besides  the 
members  of  his  own  family,  excepting  during  his  visits,  to 
London.  But  these  visits  became  each  year  more  curtailed ;  and 
though  to  the  last  his  mind  retained  all  its  freshness  and 
activity,  it  was  evident  to  those  about  him  that  he  wanted  more 
frequent  collision  with  minds  similarly  constituted  to  his  own ; 
which  is  always  more  requisite  to  powerful  and  original  intel- 
lects than  to  those  of  humbler  capacities. 

Mr.  Knight's  first  communication  to  the  Royal  Society  was 
a  paper  "  Upon  the  inheritance  of  decay  among  fruit- 
trees,  and  the  propagation  of  debility  by  grafting,"  read 
April  30,  1795  ;  and,  in  1/97,  he  published  a  "  Treatise  on  the 
culture  of  the  apple  and  pear,  and  on  the  manufacture  of 
cyder  and  perry."  In  this  work  he  repeated  the  same  opinions 
which  he  had  advanced  in  his  paper,  viz.,  that  vegetable,  like 
animal  life,  has  its  fixed  periods  of  duration ;  and  that  however 
the  existence  of  a  variety  of  a  fruit-tree  may  be  protracted 
beyond  the  natural  life  of  the  original  seedling  plant,  by  graft- 
ing, or  by  unusually  favourable  circumstances  of  soil  or 
situation,  still  there  is  a  period  beyond  which  the  debility  inci- 
dent to  old  age  cannot  be  stimulated ;  and  to  this  he  attributed 
the  cankered  and  diseased  state  of  most  of  the  trees  of  the  old 
varieties  of  cyder  apples  in  the  orchards  of  Herefordshire. 

This  hypothesis  was  so  contrary  to  generally  received 
opinions,  that  at  first  it  met  with  considerable  opposition  ;  but 
the  increasing  decay  of  the  old  fruits,  even  where  grafted  on  the 
most  vigorous  stocks,  and  the  superior  healthiness  of  the  new 
varieties  produced  from  seed,  has  caused  Mr.  Knight's  theory 
to  be  now  almost  universally  adopted.  To  remedy  the  ill-conse- 
quences that  would  have  followed  the  decay  of  the  old  fruits, 
he  set  about  raising  new  varieties  of  apples  and  pears  from 
seed  ;  but  instead  of  following  the  old  method  of  merely  selecting 
seeds  from  good  kinds*,  it  occurred  to  him,  that  by  artificially 

*  So  long  ago  as  1626,  a  Treatise  on  Orchards  was  published  by  "William 
Lawson,  in  which  he  recommends  for  forming  an  orchard,  that  "  the  ground  be 


THOMAS    ANDREW    KNIGHT,    ESQ.  13 

impregnating  blossoms  with  the  pollen  of  a  different  variety, 
possessing  qualities  of  a  contrary  nature,  but  calculated,  if  com- 
bined with  those  of  the  kind  operated  upon,  to  produce  excel- 
lence, and  by  then  raising  plants  from  the  seeds  so  produced, 
the  chances  of  obtaining  valuable  varieties  would  be  considerably 
increased ;  and  though  many  of  the  apples  at  first  raised  from 
seed  in  this  manner  did  not  answer  his  expectations,  he  event- 
ually succeeded  in  creating  new  varieties  of  many  fruits  and 
excellent  vegetables,  which  have  long  been  cultivated  and  highly 
prized  by  the  horticulturists  of  England,  and  probably  by  those 
of  most  civilised  countries  to  whose  climate  they  are  suited. 

The  idea  of  improving  fruits  by  crossing  seems  to  have  been 
entertained  by  Lord  Bacon,  though  he  was  ignorant  of  the 
method  of  accomplishing  it.  After  stating  the  effects  of  this 
course  in  producing  mules  in  the  animal  world,  he  thus  pro- 
ceeds :  "  The  compounding  and  mixture  of  plants  is  not  found 
out,  which,  nevertheless,  if  it  be  possible,  is  more  at  command 
than  that  of  living  creatures  ;  wherefore  it  were  one  of  the  most 
noble  experiments  touching  plants  to  find  this  art ;  for  so  you 
may  have  a  great  variety  of  new  plants  and  flowers  yet 
unknown.  Grafting  doth  it  not :  that  mendeth  the  fruit,  or 
doubleth  the  flower,  but  it  hath  not  the  power  to  make  a  new 
kind — for  the  scion  ever  overruleth  the  stock*." 

If  to  Lord  Bacon  must  be  assigned  the  merit  of  having  first 
suggested  the  possibility  of  producing  new  fruits  in  this  manner, 
it  was  reserved  for  Mr.  Knight  to  discover  the  means  by  which 
those  "most  noble  experiments"  were  to  be  rendered  suc- 
cessful ;  and  to  his  discoveries  we  undoubtedly  owe  the  innu- 
merable varieties  of  excellent  fruits  that  supply  our  tables,  as 

sown  with  kernels  of  the  best  and  soundest  apples  and  pears,  and  to  leave  the 
likeliest  plants  only  in  the  natural  place,  removing  others,  as  time  and  occasion 
may  require ;"  but  this  practice  does  not  appear  to  have  been  general,  for 
Evelyn  in  his  "  Sylva,"  published  some  years  afterwards,  says — "  Nothing  is 
more  facile  than  to  raise  new  kinds  of  apples,  ad  infinitum,  from  kernels  ;  yet  in 
that  apple  county  (Hereford),  so  much  addicted  to  orchards,  we  could  never 
encounter  more  than  two  or  three  persons  that  did  believe  it." 
*  Quarto  edit.  1790,  p.  97. 


14  LIFE    OF 

well  as  the  almost  endless  profusion  of  beautiful  flowers  with 
which  the  process  of  hybridization  has  adorned  our  green- 
houses and  flower-gardens. 

The  following  extract  from  a  letter  from  Sir  Joseph  Banks 
shows  how  new  to  the  horticulturists  of  the  year  1798  was  this 
system,  and  how  important  he  foresaw  the  results  would  be. 

"  I  have,  some  time  ago,  read  your  work  on  the  culture  of 
cyder  fruits  with  much  pleasure.  Your  experiments  on  apples 
and  grapes  must  be  very  tedious,  but  surely  the  success  of  those 
on  annual  plants  will  induce  you  to  persevere.  The  chances  of 
a  valuable  offspring  must  be  materially  multiplied  by  the 
stimulus  of  a  different  male  ;  who  can  tell  but  that  this,  through 
the  medium  of  bees,  or  of  the  wind,  is  the  only  real  origin  of 
new  varieties  ?  When  you  consider  your  experiments  upon  the 
fecundation  of  plants,  and  improving  the  kinds  of  them  by 
coupling  the  best  males  and  females  of  each  sort,  as  unimport- 
ant matters,  you  really  act  very  differently  from  what  I  feel 
myself  disposed  to  do  on  the  occasion.  I  am  loth  to  speak  in 
a  dictatorial  style,  if  my  opinion  differs  from  yours ;  but  I  do 
confess,  I  think  no  experiments  promise  more  public  utility 
than  those  for  improving  the  breeds  of  vegetables." 

From  this  time  Mr.  Knight  continued  to  contribute  to  the 
Transactions  of  the  Royal  Society  the  results  of  numerous  expe- 
riments on  the  "  Fecundation  of  plants,"  the  cause  of  the 
"  Rise  of  the  sap  in  trees,"  the  "  Vessels  through  which  it 
ascends  and  descends,"  the  "  Causes  which  influence  the 
direction  of  the  root,"  and  a  variety  of  similar  subjects.  In  all 
these  researches,  the  ingenuity  and  originality  of  the  experi- 
ments, and  the  care  with  which  the  results  were  given,  were  so 
great,  that  the  most  captious  of  subsequent  writers  have 
admitted  the  correctness  and  value  of  the  facts  established  by 
him :  though  the  inferences  he  drew  from  them  have,  in  some 
instances,  been  disputed.  The  great  object  he  always  had  in 
view,  and  which  he  pursued  through  his  long  life  with  unde- 
viating  steadiness  of  purpose,  was  utility ;  and  it  was  only  when 
facts  had  some  great  practical  bearing  that  he  applied  himself 


THOMAS    ANDREW    KNIGHT,    ESQ.  15 

seriously  to  investigate  the  phenomena  connected  with  them. 
His  experiments  on  the  descent  of  the  radicle  excited  great 
attention  among  scientific  horticulturists,  and  have  perhaps 
been  more  generally  known  than  any  of  his  other  researches*. 
The  machinery  by  which  he  subjected  seeds  to  rotary  motion 
during  the  process  of  germination  was  constructed  by  his  own 
hands,  with  no  other  assistance  than  that  of  an  old  carpenter, 
who  was  not  remarkable  for  his  intelligence.  A  representation 
of  this  machinery  is  given  with  the  paper  describing  the  experi- 
ment in  the  present  work,  and  also  in  Sir  H.  Davy's  Agricultural 
Chemistry,  in  which  Sir  H.  adopts  Mr.  Knight's  hypothesis, 
that  plants  probably  owe  the  peculiar  direction  of  their  roots 
and  branches  almost  entirely  to  the  force  of  gravitation.  Mr. 
Knight  however,  in  a  paper  published  a  few  years  later,  details 
some  experiments  which  show,  that  certain  other  natural 
causes  may  occasionally  so  far  act  in  opposition  to  gravitation, 
as  to  divert  the  radicle,  as  well  as  the  fibrous  roots,  from  the 
direction  which  gravitation  would  have  impelled  them  to 
follow  ^. 

The  experiments  on  the  effects  of  rotary  motion  in  counter- 
acting the  effects  of  gravitation  were  repeated  by  M.  Dutrochet 
and  other  foreign  physiologists,  with  various  modifications,  but 
always  followed  by  the  same  results.  On  this  subject  a  corres- 
pondence commenced  between  M.  Dutrochet  and  Mr.  Knight, 
which  was  continued  during  the  remainder  of  his  life. 

Among  other  facts  established  by  Mr.  Knight's  experiments 
is,  that  the  ascending  sap  undergoes  a  change  in  its  progress 
through  the  leaves,  somewhat  analogous  to  that  which  takes 
place  in  the  blood  of  animals  in  its  passage  through  the  lungs  ; 
and  that  this  elaborated  sap  afterwards  descends  through  the 
bark,  depositing  in  its  course  an  inner  layer  of  bark,  and  a  new 
layer  of  wood,  while  the  old  external  bark  cracks  and  peels  off 
as  the  stem  or  branch  of  the  tree  increases  its  dimensions,  by 
the  annual  deposition  of  a  layer  of  fresh  wood.  His  views  as  to 
the  vessels  through  which  the  sap  ascends  to  the  leaf  have  not 

*   See  below,  Paper  No.  VII.  f  See  below,  Paper  No.  XIII. 


16  LIFE    OF 

been  so  generally  adopted  ;  but  this  is  a  point  on  which  some 
diversity  of  opinion  still  exists  among  physiologists.  Mr.  Knight 
considered  the  rays  which  are  seen  to  diverge  from  the  centre 
of  a  horizontal  section  of  the  trunk  of  a  tree,  and  which  in 
longitudinal  sections  is  known  as  the  silver  grain,  to  be  the 
vessels  through  which  the  descending  sap  is  conveyed  from  the 
bark  into  the  cellular  cavities  of  the  wood,  there  to  remain  till 
it  combines  with  the  ascending  fluid  in  the  following  spring. 

The  following  letter  from  Mons.  Mirbel  (though  bearing  date 
a  few  years  later)  refers  to  the  papers  written  by  Mr.  Knight 
at  this  time ;  and  the  candid  and  liberal  spirit  in  which  it  is 
dictated  is  so  honourable  to  the  writer,  that  the  insertion  of 
it  here  reflects  even  more  credit  on  him  than  on  Mr.  Knight. 
The  feelings  with  which  it  was  received  by  the  latter  will  be 
seen  by  the  following  note,  found  among  his  papers : — 

"  M.  Mirbel  has  changed  his  opinions  respecting  the  transmu- 
tation of  bark  into  alburnum  ;  and  in  a  private  letter  conceded 
the  point  to  me,  in  so  manly  and  honourable  a  way,  that  I 
really  felt  much  more  sorry  that  M.  Mirbel  should  have 
found  himself  called  upon  to  make  such  a  concession,  than  joy 
at  my  own  triumph,  which  I  may  be  supposed  to  have  felt.  The 
conduct  of  M.  Mirbel  greatly  raises  him  in  my  esteem,  and  I 
should  feel  proud  to  follow  his  example." 

"  Paris,  ce  20  Mai,  1816. 

"  MONSIEUR  : 

"  J'ai  re9U  la  lettre  dont  vous  m'avez  honore,  et  je  prie  rnon 
ami,  Mons.  le  Comte  de  Mosbourg,  qui  part  pour  TAngleterre, 
de  vous  porter  ma  reponse.  Mon  ouvrage  etoit  deja  imprime 
quand  j'ai  eu  connaissance  de  vos  opinions ;  elles  m'ont  d'abord 
paru  specieuses,  et  ensuite  elles  m'ont  paru  tres-bien  fondees 
Vous  m'avez  ouvert  les  yeux,  et  je  vous  en  remercie,  car  de 
meme  que  vous  je  ne  cherche  que  la  verite.  Se  refuser  a 
1'evidence  est  une  folie  dont  un  savant  est  tot  ou  tard  puni  par 
la  perte  de  sa  reputation.  II  vaut  mieux  changer  de  route  que 
d'en  suivre  une  qui  nous  egare.  Je  reconnois  aujourd'hui  que 
le  liber  ne  se  change  point  en  bois ;  qu'il  est  constamment 


THOMAS    ANDREW    KNIGHT,    ESQ.  17 

repousse  a  la  circonference ;  et  qu'il  se  forme  annuellement, 
entre  le  corps  ligneux  et  Tecorce,  une  couche  de  cambium, 
laquelle  regenere  le  liber  et  le  bois.  Je  crois  que  c'est  a-peu- 
pres  la  votre  doctrine  ;  c'est  en  etudiant  la  nature  que  j'ai  appris 
a  apprecier  vos  travaux.  J'ai  repete  les  experiences  de  Duha- 
mel ;  il  m'a  semble  que  s'il  avoit  fait  des  observations  micro- 
scopiques,  il  seroit  arrive  aux  memes  resultats  que  vous,  et 
n'auroit  pas  laisse  ses  lecteurs  dans  une  doute  desesperante. 

"  M.  Aubert  du  Petit-Thouars  a  combattu  mes  opinions,  mais 
ce  qu'il  a  mis  a  la  place  n'a  pu  me  satisfaire ;  c'est  la  raison 
pourquoi  j'ai  fait  peu  d'attention  a  sa  critique ;  la  votre  m'a 
ouvert  les  yeux  sur  mon  erreur.  J'ai  fait  une  longue  suite  de 
recherches  sur  FOrme,  le  Pommier,  le  Cerisier,  et  sur  beaucoup 
d'autres  arbres  encore ;  je  crois  cette  fois  avoir  saisi  la  nature 
sur  le  fait,  et  je  saisirai  la  premiere  occasion  de  refuter  moi-meme 
ma  premiere  doctrine.  Je  1'ai  serieusement  examinee,  et  je  pense 
qu'il  me  seroit  facile  de  reordonner  tous  les  faits,  et  de  rendre 
cette  partie  de  mon  travail  beaucoup  plus  exacte 

"Daignez  agreer  1'hommage  de  la  haute  consideration  avec 
laquelle  j'ai  1'honneur  d'etre,  Monsieur, 

"  Votre  tres-humble  serviteur, 

"  B.  MIRBEL*." 

*    TRANSLATION    OF    M.    MTRBEL^S    LETTER. 
"  SIR  : 

"  I  received  the  letter  with  which  you  have  honoured  me  on  the  llth  of  last 
February,  and  I  have  requested  my  friend  M.  Le  Comte  de  Mosbourg,  who  is 
going  to  England,  to  convey  my  answer  to  you.  My  work  was  already  printed 
when  I  became  acquainted  with  your  opinions ;  at  first  they  appeared  to  me 
specious,  but  now  they  seem  to  me  to  be  well  founded. 

''  You  have  opened  my  eyes,  and  I  thank  you  for  it ;  for,  like  yourself,  I  seek 
only  for  truth.  To  refuse  to  receive  evidence  is  a  folly  for  which  a  savant  is 
sooner  or  later  punished  by  loss  of  reputation. 

"  It  is  better  to  change  a  route  than  to  follow  one  that  leads  us  astray.  I 
acknowledge  now  that  the  bark  does  not  change  into  wood ;  but  that  there  is 
continually  deposited  between  the  wood  and  the  bark  a  layer  of  cambium  which 
generates  new  wood  and  bark.  I  believe  this  is  nearly  your  doctrine.  It  is  in 
studying  nature  that  I  have  learned  to  appreciate  your  works. 

"  I  have  repeated  the  experiments  of  Duhamel,  and  it  appears  to  me,  that  if  he 
had  made  microscopic  observations,  he  would  have  arrived  at  the  same  results  as 

C 


18  LIFE   OF 

In  the  year  1805  Mr.  Knight  was  elected  a  Fellow  of  the 
Royal  Society,  and  on  the  4th  of  November,  1806,  the  Copley 
Medal  was  voted  to  him  for  his  papers  on  vegetable  physiology, 
and  presented  at  the  anniversary  meeting  on  the  1st  of 
December  following,  when  Sir  Joseph  Banks  delivered  an 
address  expressive  of  the  sense  the  society  entertained  of  the 
value  of  his  discoveries. 

But  the  time  and  attention  he  devoted  to  scientific  pursuits 
did  not  divert  him  from  the  prosecution  of  objects  which, 
though  less  calculated  to  secure  him  an  eminent  rank  among 
philosophers,  were  gaining  him  the  still  more  enviable  distinc- 
tion of  a  benefactor  of  his  country. 

He  had  by  this  time  become  well  known  as  a  practical  agri- 
culturist, and  an  improver  of  the  breed  of  Herefordshire  cattle. 
The  stock  of  this  county  had  been  long  distinguished  for  its 
superior  quality  ;  the  origin  of  this  superiority  he  had  taken 
some  pains  to  discover,  and  the  result  of  his  inquiries  led  him 
to  attribute  it  to  the  introduction  from  Flanders*  of  a  breed  of 

yourself,  and  would  not  have  left  his  reader  in  a  perplexing  state  of  doubt. 
M.  Aubert  du  Petit  Thouars  has  combated  my  opinions,  but  those  he  has  sub- 
stituted have  not  satisfied  me,  for  which  reason  I  have  paid  little  attention  to  his 
criticisms.  You  have  opened  my  eyes  to  my  errors.  I  have  made  a  long 
course  of  experiments  on  the  elm,  the  apple-tree,  the  cherry,  and  on  many 
other  trees,  and  I  believe  I  have  this  time  detected  nature  in  her  operations, 
and  I  shall  myself  seize  the  first  occasion  to  refute  my  original  doctrine.  I  have 
seriously  examined  it,  and  I  think  it  will  be  easy  to  rearrange  the  facts,  and  to 
make  this  part  of  my  work  much  more  correct. 

"  I  have  not  yet,  sir,  received  the  work  that  you  announce.  What  I  know  of 
you  gives  me  beforehand  a  high  opinion  of  your  new  researches.  It  is  very  im- 
portant that  we  should  clear  up  the  chaos  of  vegetable  physiology  :  this  branch 
of  general  science  is  overloaded  with  error,  and  with  fanciful  theories  ;  we  shall 
only  succeed  in  clearing  it  up  by  substituting  strict  observation  instead  of  vain 
hypothesis,  and  severe  logic  for  frivolous  reasoning :  it  is  for  you,  above  all 
others,  to  do  us  this  service.  Accept  the  testimony  of  the  high  consideration 
with  which  I  have  the  honour  to  be,  Sir, 

"  Your  very  humble  Servant, 

"  MIR  BEL." 

*  In  Cuyp's  pictures  the  cattle  are  usually  represented  of  the  Herefordshire 
colour,  with  white  faces. 


THOMAS    ANDREW    KNIGHT,    ESQ.  19 

cattle  by  Lord  Scudamore,  who  died  in  1671,  to  whom  the 
orchards  of  Herefordshire  were  also  indebted  for  the  introduc- 
tion of  many  of  their  best  apples. 

An  agricultural  society  was  established  in  Herefordshire  in 
1 797,  in  the  formation  of  which  Mr.  Knight  took  an  active  part ; 
and  to  the  end  of  his  life  he  was  almost  invariably  present  at 
its  annual  show.  Both  here  and  at  Smithfield  his  cattle 
frequently  obtained  prizes,  and,  in  his  usual  liberal  spirit.,  he,, 
on  several  occasions,  offered  premiums  at  Hereford  for  objects 
that  he  considered  of  importance  to  the  farming  interests. 

In  the  year  1802,  a  Mr.  Davidson  was  sent  to  England,  by 
order  of  the  Emperor  of  Russia,  to  procure  some  of  the  improved 
breed  of  cattle  and  sheep  for  the  Imperial  farm  ;  and  he  was 
recommended  by  Sir  Joseph  Banks  to  Mr.  Knight,  through 
whose  means  a  selection  was  made  from  the  stock  of  other  cele- 
brated breeders,  as  well  as  his  own,  but  for  which  he  would  not 
allow  more  than  the  market  price  to  be  charged.  This  com- 
mission was  executed  so  much  to  the  Emperor's  satisfaction, 
that  on  Mr.  Davidson's  return  to  St.  Petersburgh,  the  following 
letter  was  received  by  Mr.  Knight  :— 

"  St.  Peterslurgh,  fall  January,  1803. 
c;  SIR  : 

"  On  his  arrival  here,  Mr.  Davidson  having  represented  the 
many  civilities  and  attentions  he  had  received  from  you  while 
purchasing  sheep  and  cattle  for  the  Emperor,  and  also  the  very 
liberal  and  handsome  manner  in  which  you  had  parted  with  a 
heifer  and  several  of  your  valuable  flock  of  sheep,  and  procured 
others  for  him  from  your  neighbours,  I  am  directed  by  his 
imperial  majesty  to  thank  you,  in  the  warmest  manner,  for  the 
favours  thus  conferred  upon  him  :  he,  at  the  same  time,  requests 
you  will  have  the  goodness  to  thank  Mr.  Martin  and  Mr. 
Steward  for  their  kindness.  Should  there  be  anything  of  the 
same  nature  in  his  dominions  which  you  might  imagine  could 
be  of  the  least  service  to  you,  he  will  think  himself  happy  in 
any  opportunity  you  may  afford  him  of  returning  the  obligation. 

c  2 


20  LIFE    OF 

I  shall  esteem  myself  favoured  by  any  application  to  me  upon 
the  subject,  and  will  immediately  upon  receiving  it  lay  it  before 
his  imperial  majesty. 

"  I  have  the  honour  to  be, 

"  Your  obedient  humble  servant, 

"N.  NOVOSSILZOFF." 

Mr.  Knight  had,  in  1799,  received  a  gift  from  George  III.  of  a 
Merino  ram,  some  of  which  had  been  imported  for  the  purpose  of 
improving  the  wool  of  the  native  breeds  of  sheep ;  and  he  had 
obtained  a  mixed  breed,  between  the  Merino  and  the  Ryeland, 
to  which  he  for  some  years  paid  much  attention,  and  had  regu- 
larly reported  the  result  of  these  experiments  to  Sir  JosephBanks. 
Not  many  years  before  his  death,  he  imported  some  Norwegian 
ponies,  which,  though  neither  particularly  handsome  nor  active, 
he  thought,  from  their  great  strength  and  hardy  habits,  were 
likely  to  effect  an  improvement  in  the  breed  of  horses  adapted  to 
agricultural  and  other  uses,  where  strength  and  hardihood  are 
more  valuable  qualities  than  spirit  or  beauty.  A  cross  with  the 
London  dray-horse  produced  some  animals  combining  many  of 
the  good  qualities  of  both  parents. 

It  was  during  his  annual  visit  to  the  metropolis,  in  the 
spring  of  1803,  that  he  was  introduced,  by  their  mutual 
friend  Sir  Joseph  Banks,  to  Sir  Humphrey  (then  Mr.)  Davy, 
who  was  about  to  deliver  a  course  of  lectures  on  "  the  Chemistry 
of  Agriculture,"  before  the  Board  of  Agriculture,  and  who  was 
anxious  to  avail  himself  of  Mr.  Knight's  experience  and  en- 
lightened views  on  some  of  the  points  on  which  he  had  to  treat. 

The  acquaintance  thus  begun  soon  ripened  into  a  warm 
friendship,  and  a  correspondence  commenced  which  was  con- 
tinued, with  few  interruptions,  till  the  lamented  death  of  Sir 
Humphrey  in  1829. 

Mr.  Davy  visited  Mr.  Knight  at  Elton  in  the  summer  of 
1803,  in  company  with  Mr.  Greenough,  with  whom  he  was 
proceeding  to  make  a  tour  in  Wales  and  Ireland  ;  and  for  many 
years  afterwards  he  rarely  failed  to  spend  some  days  either 


THOMAS    ANDREW    KNIGHT,    ESQ.  21 

at  Elton  or  Downton  Castle,  for  the  purpose  of  enjoying  his 
favourite  amusement  of  fly-fishing.  These  days  he  commemo- 
rates in  the  following  passage  of  his  "  Salmonia"  : — 

Day  8tk.  Scene,  Downton. 

"  Halietus  :  I  do  not  think,  as  the  day  advances,  there  will  be 
any  deficiency  of  light,  and  I  shall  not  be  sorry  for  this,  as  it 
will  enable  you  to  see  the  grounds  of  Downton,  and  the  dis- 
tances in  the  landscape,  to  more  advantage. 

"  Poietes  :  This  spot  is  really  very  fine  ; — the  fall  of  water — 
the  picturesque  mill — the  abrupt  cliff,  and  the  bank  covered 
with  noble  oaks  above  the  river,  compose  a  scene  such  as  I  have 
rarely  beheld  in  this  island. 

"  Halietus  :  We  will  wander  a  little  longer  through  the  walks. 
There  you  will  enter  a  subterraneous  passage  in  the  rock  beyond 
the  mossy  grotto.  Behold  the  castle  or  mansion-house,  clothed 
in  beautiful  vegetation  of  which  the  red  creeper  is  most  distinct, 
rises  above  on  the  hill !  After  we  have  finished  our  walk  and  our 
fishing,  I  will,  if  you  please,  take  you  to  the  house,  and  intro- 
duce you  to  the  worthy  master,  whom  to  know  is  to  love,  and 
to  whom  all  good  anglers  should  be  grateful,  and  who  has  a 
stronger  claim  to  a  more  extensive  gratitude — that  of  his 
country  and  of  society — by  his  scientific  researches  on  vegetable 
nature,  which  are  not  merely  curious  but  useful,  and  which 
have  already  led  to  great  improvements  in  our  fruits  and  plants, 
and  generally  extended  the  popularity  of  horticulture." 

The  following  letters  contain  allusions  to  some  of  these  visits, 
which  were  a  source  of  so  much  gratification  to  Mr.  Knight, 
that  it  is  hoped  no  apology  will  be  required  for  thus  preserving 
a  memorial  of  them  : 

"  Royal  Institution,  August  25, 1808. 

"  MY  DEAR  SIR  : 

16 1  have  just  sent  your  excellent  paper  on  the  functions  of 
the  alburnum  to  press.  Do  you  wish  for  any  extra  copies  ? 
Our  society  will  expect  with  anxiety  a  continuation  of  your 
important  researches ;  and  I  trust  we  shall  have  a  paper  from 


22  LIFE    OF 

you  the  beginning  of  the  next  session.  I  shall  ask  permission 
to  witness  the  results  of  some  of  your  experiments  in  the  course 
of  the  next  month.  I  think  of  leaving  London  for  a  fortnight, 
and  there  is  no  place  that  I  have  so  great  a  desire  to  visit  as 
your  delightful  scenery.  The  hope  of  the  pleasure  of  your 
society,  the  banks  of  the  Teme,  and  the  grayling  fishing,  are  an 
assemblage  of  temptations  which  will  induce  me  to  bend  my 
course  towards  Herefordshire.  Two  philosophical  friends,  Mr. 
Children  and  Mr.  Pepys,  have  promised  to  be  my  companions 
in  this  little  journey,  and  we  propose  to  establish  our  head- 
quarters at  Leominster  and  Leintwardine,  from  which  last  place 
I  shall  have  the  opportunity  of  paying  you  a  visit,  and  I  hope 
you  will  permit  us  all  to  join  in  a  fly-fishing  party. 

"  I  have  been  much  engaged  in  experiments  since  I  had  the 
pleasure  of  seeing  you,  and  I  have  succeeded  in  decomposing 
all  the  earths*,  which  turn  out  to  be  highly  combustible  metals 
united  to  oxygen.  I  am,  my  dear  sir,  with  respectful  compli- 
ments to  Mrs.  Knight, 

"  Very  sincerely  your  obliged, 

"  H.  DAVY." 

"  Cobham,  Kent,  November  3,  1810. 

"My  DEAR  SIR: 

"  I  cannot  yet  profit  by  the  kind  permission  you  have  given 
me  to  submit  my  ideas  upon  vegetable  chemistry  to  your  obser- 
vations and  corrections,  for  I  have  only  just  commenced  that 
part  of  my  labours,  and  I  do  not  hope  to  be  able  to  get  through 
it  till  the  beginning  of  the  spring.  In  considering  the  physiology 
of  the  subject,  I  shall  have  little  to  do  but  to  record  your 
labours,  for  you  have  created  almost  all  the  science  we  possess 
on  that  interesting  subject ;  my  aim  will  be  to  throw  out  some 
chemical  hints  upon  the  nature  of  vegetable  nutrition,  and  the 
conversion  of  dead  into  living  matter,  and  which  may  at  length 

*  The  experiments  thus  simply  reported  form  the  subject  of  his  second 
Bakerian  Lecture ;  and,  "  since  Newton's  first  discoveries  in  Optics,  it  may  be 
questioned,  whether  so  successful  an  instance  of  philosophical  induction  has  ever 
been  afforded." — See  Paris's  Life  of  Sir  Humphrey  Davy. 


THOMAS    ANDREW    KNIGHT,    ESQ.  23 

produce  new  investigations.  I  have  often,  since  I  was  at 
Downton,  had  occasion  to  check  feelings  which  certainly  were 
too  selfish  to  be  indulged  in  for  more  than  a  moment.  When 
I  have  seen  a  fine  day,  and  the  flies  sporting  in  the  sunshine,  I 
have  sighed  and  said,  '  What  would  such  a  day  be  worth  at 
Downton  ! '  In  the  first  week  after  I  returned,  I  rejoiced  when 
the  wind  blew  from  the  east. 

u  We  were  unfortunate  in  our  weather  :  but  to  have  had  a 
week  of  fine  days,  and  good  fishing,  added  to  our  general  stock 
of  pleasures  whilst  we  were  with  you,  would  have  been  above 
the  common  balance  of  human  enjoyment,  and  we  might  have 
considered  ourselves,  in  the  superstitious  spirit  of  the  ancients, 
nimisfortunati. 

"  I  have  been  much  employed,  since  my  return,  in  pursuing 
investigations  upon  the  nature  of  air  and  water,  and  their  con- 
version into  each  other*.  The  inquiry  becomes  more  difficult  as 
it  becomes  more  refined  ;  but  I  hope  to  be  able  to  give  some 
decided  views  upon  the  subject.  Many  thanks  for  the  interest 
you  express  in  my  experiments.  I  am  little  anxious  about 
speculative  opinions,  yet  I  shall  omit  no  explanation  that  may 
assist  research :  facts  are  what  we  ought  to  value,  and  they  must 
be  permanent  even  among  the  revolutions  of  opinion. 

"  When  the  weight  of  the  atmosphere  was  first  proved  by  the 
Torricellian  experiment,  the  Italian  philosopher  was  abused, 
and  a  thousand  false  explanations  of  the  barometer  given  by 
monks  and  Jesuits.  One  never  hears  now  of  Father  Linus's 
invisible  threads  of  suspension  for  the  mercury !  the  fact 
belongs  to  the  immutable  in  natural  philosophy. 

"  I  beg  to  be  remembered  very  respectfully  and  kindly  to 
Mrs.  Knight,  and  all  the  family  at  Downton.  Believe  me  your 
goodness  and  hospitality  have  not  been  thrown  away  upon  an 
ungrateful  man. 

"  I  am,  my  dear  Sir, 

"  Very  truly,  always  your  obliged, 

"H.  DAVY. 

*  The  results  of  these  experiments  will  be  seen  in  the  Bakerian  Lectures  of 
1810. 


24  LIFE    OF 

"  This  is  almost  the  first  hour  of  leisure  that  I  have  had 
since  I  received  your  letter.  I  am  here  at  grass  for  two  or 
three  days,  in  the  midst  of  fine  woods,  but  without  a  Teme  or 
a  Downton." 

The  paper  "  On  the  Functions  of  the  Alburnum,"  alluded  to  in 
Sir  H.  Davy's  second  letter,  was  published  by  the  Royal  Society, 
but  has  not  been  included  in  the  selection  of  papers  for  the 
present  work,  because  the  theory  it  presents  has  not  been 
established,  and  it  will  be  seen,  that  at  a  subsequent  period, 
Mr.  Knight  himself  was  disposed  to  adopt  the  opinions  of  M. 
Dutrochet,  who  ascribes  the  ascent  of  the  sap  to  electrical  agency. 
A  letter  addressed  to  Sir  Joseph  Banks  on  this  subject  will  show 
what  were  his  views  at  that  time,  and  the  observations  on 
which  they  were  founded. 

"  August  14,  1799. 
"  MY  DEAR  SIR  : 

"  I  am  very  much  obliged  to  you  for  my  ram,  which  arrived 
very  safe,  and  in  perfectly  good  condition.  I  shall  try  different 
crosses  with  him  this  autumn,  and  I  shall  have  great  pleasure 
in  sending  you  the  results  of  such  trials  as  I  shall  make.  You 
may  depend  on  the  statements  I  shall  send  being  perfectly 
accurate,  if  without  any  other  merit. 

"  I  will  take  this  opportunity  of  mentioning  the  observations 
and  opinions  I  spoke  of  in  my  last  letter,  relative  to  the  ascent 
of  the  sap  in  trees,  though  I  fear  it  will  occasion  me  to  trouble 
you  with  an  epistle  of  immoderate  length.  If  I  become  a  trou- 
blesome scribbler  to  you,  I  must  claim  your  pardon  on  the 
ground  that  you  have  made  me  such ;  for  without  the  attention 
I  have  been  honoured  with  from  you,  I  am  certain  I  should 
never  (in  print)  have  scribbled  at  all.  In  the  observations  I 
am  going  to  state,  there  will  probably  be  little,  perhaps  nothing, 
new  to  you ;  but  as  I  do  not  know  how  much  will  be  new,  I  will 
state  the  whole  as  if  I  supposed  it  such. 

"  It  is,  I  think,  easy  to  prove  every  theory  I  have  seen  on  the 


THOMAS    ANDREW    KNIGHT,    ESQ.  25 

subject  false ;  that  of  capillary  attraction  is  surely  without 
foundation,  not  being  any  way  equal  to  propel  the  sap  in  the 
manner  described  by  Hales.  Dr.  Hunter's  opinion,  that  the  sap 
is  raised  by  the  expanded  air-vessels  pressing  on  the  sap- 
vessels,  does  not  agree  with  the  fact,  that  the  sap  flows  with 
great  force  when  the  temperature  of  the  surrounding  air  is 
declining  ;  nor  do  I  see  a  force  here  adequate  to  the  effect  pro- 
duced. Dr.  Darwin's  imagination  is  generally  too  strong  for  his 
judgment ;  and  it  has,  I  suspect,  created  more  in  this  case  than 
nature  has  done.  My  theory  may  perhaps  be  more  absurd 
than  either;  but  such  as  it  is,  I  will  profit  by  the  permission  you 
have  given  me  to  lay  it  before  you. 

"  There  are  two  kinds  of  grain  in  wood  ;  the  one  usually  called 
the  false  or  bastard,  the  other  the  true  or  silver  grain.  The 
former  consists  of  those  concentric  circles  which  mark  the 
annual  increase  of  the  tree  ;  and  the  latter  is  formed  of  polished 
lamina?  diverging  in  every  direction,  from  the  centre  towards 
the  bark  of  the  tree,  slightly  adhering  to  each  other  at  all 
times,  and  scarcely  at  all  during  the  spring  and  summer,  whence 
the  increased  brittleness  of  wood  at  these  seasons.  If  you  will 
examine  a  piece  of  English  oak,  you  will  find  the  laminae  I 
describe,  and  that  every  sap  tube  is  touched  by  it  at  short  dis- 
tances, and  is  slightly  diverted  by  it  from  its  course.  If  these 
laminae  be  expansible  by  increase  of  temperature,  I  conceive 
that  they  are  placed  as  well  as  possible  to  impel  the  sap  to  the 
extremities ;  and  that  they  are  expansible  by  change  of  tempe- 
rature I  am  led  to  suspect,  by  their  being  much  affected  and 
put  in  motion  by  the  state  of  the  atmosphere  long  after  the  tree 
has  ceased  to  live.  I  shall  at  present  confine  my  observations 
to  the  English  oak,  though  the  same  observations  are  applicable 
in  a  greater  or  less  degree  to  every  other  kind  of  tree,  and  even 
to  the  cabbage-stalk.  In  sawing  oak  into  boards,  it  is  usual  to 
cut  it,  as  much  as  is  possible,  into  what  are  called  quarter 
boards;  being  so  named  from  the  tree  being  first  cut  into 
quarters.  In  a  true  quarter  board  the  laminae  of  the  silver 
grain  lie  exactly  parallel  with  the  surface  of  the  board,  and  a 


26  LIFE    OF 

board  thus  sawn  is  never  seen  to  deviate  from  its  horizontal 
position  when  laid  in  a  floor.  If,  on  the  contrary,  a  board  be 
sawn  across  the  silver  grain,  it  will  during  many  years  be  inca- 
pable of  bearing  changes  of  temperature  and  moisture  without 
being  warped,  nor  will  the  strength  of  very  strong  nails  be  able 
to  prevent  the  inconvenience  thence  arising.  On  this  account 
quarter  boards  are  always  sold  at  a  much  higher  price  than 
others,  which  are  here  called  bastard  boards.  If  a  board  of  the 
latter  kind  be  laid  in  the  floor  with  that  surface  uppermost 
which  grew  nearest  the  centre  of  the  tree,  it  will  show  a  dispo- 
sition to  become  convex  ;  if  with  the  other  surface  uppermost, 
concave.  The  latter  being  much  more  inconvenient,  this  cir- 
cumstance ought  to  be  attended  to  by  workmen  ;  but  it  is,  I 
believe,  wholly  unknown  to  them.  I  do  not  suppose  this  pro- 
perty in  wood  to  have  been  attended  to  by  the  makers  of 
harpsichords  or  pianofortes ;  if  it  has  not,  it  is  probably  the 
cause  why  some  instruments  keep  in  tune  better  than  others. 

"  You  have,  perhaps,  remarked  that  when  an  oak  has  been 
stript  of  its  bark  and  exposed  to  the  sun  and  air,  its  surface 
becomes  full  of  small  clefts,  which  continue  for  a  long  time  to 
contract  and  expand  with  the  changes  in  the  weather — you  will 
find  that  these  are  always  formed  by  the  laminae  of  the  silver 
grain  having  parted  from  each  other.  This  restless  temper  in 
it  (of  which  I  could  point  out  other  instances)  has  convinced 
me  that  it  was  not  made  to  be  idle  ;  and  as  no  other  power 
appears  to  me  to  have  been  discovered  capable  of  propelling  the 
sap  to  the  height  described  by  Dr.  Hales,  I  am  much  disposed 
to  believe  that  this  is  the  office  which  nature  has  assigned  it, 
and  that  the  following  may  possibly  be  the  mode  of  acting. 
All  bodies  being  more  or  less  expansible  by  heat,  and  the  silver 
grain  appearing  to  be  of  a  very  irritable  temper,  I  infer  that  it 
will  expand  and  press  on  the  sap  vessels,  whenever  the  tempe- 
rature of  the  surrounding  air  is  increasing  by  the  presence  of 
the  sun  or  other  causes ;  and  that  it  will  contract  again  during 
the  cold  of  the  night,  or  other  adventitious  decrease  of  heat. 
These  effects  will  first  take  place  in  the  smaller  branches — later 


THOMAS    ANDREW    KNIGHT,    ESQ.  27 

in  the  trunk  (owing  to  its  greater  bulk  and  the  temperature  of 
the  fluid  it  receives  from  the  earth),  and  last  at  the  root.  If 
we  suppose  these  laminae  to  contract  first  in  the  smaller 
branches  during  the  decreasing  temperature  of  the  evening, 
the  resistance  the  rising  fluid  will  meet  with  in  those  branches 
will  be  less  than  the  pressure  exerted  in  the  trunk  and  large 
boughs,  and  the  sap  will,  in  consequence,  flow  with  greater 
freedom  during  the  evening  and  night  (as  my  experience 
induces  me  to  believe  it  does) ;  and  during  this  time  plants 
ought,  according  to  this  theory,  to  grow  most,  as  a  few  experi- 
ments I  have  made  incline  me  to  believe  they  do.  In  the 
morning  the  increasing  temperature  of  the  air  would  put  the 
sap  in  the  smaller  branches  in  motion,  and  thus  supply  the 
progress  of  vegetation  during  the  day.  No  kind  of  weather 
appears  so  well  calculated  to  produce  the  expansion  and  con- 
traction I  have  supposed  to  exist,  as  that  in  which  there  are 
frequent  hot  gleams  of  sun  with  intervening  clouds  and  showers ; 
and  in  such  weather  I  think  plants  usually  make  the  most  rapid 
progress. 

"  When  trees  are  burst  by  frost,  it  is,  I  believe,  usually  sup- 
posed to  arise  from  the  congelation  and  consequent  expansion 
of  the  fluid  remaining  in  the  sap  vessels ;  but  this  opinion  I 
think  must  be  erroneous,  for  the  sap  vessels  (in  the  common 
kind  of  fracture)  are  not  ruptured,  nor  does  the  fracture  follow 
their  direction — it  follows  that  of  the  silver  grain  ;  and  I  believe 
that  the  internal  part  of  the  tree  is  cleft  by  the  expansion  of 
the  external  part,  owing  to  the  sudden  change  of  temperature 
in  the  end  of  long  and  hard  frosts,  as  frequently  happens  to 
other  hard  and  brittle  bodies.  The  silver  grain  is  here 
extremely  well  placed  to  produce  this  effect,  and  I  have  little 
doubt  does  produce  it.  But  there  is  another  species  of  rupture, 
common  in  pollard  trees,  which  follows  the  circular  line  of  the 
sap  vessels ;  and  this  is  probably  occasioned  by  the  freezing  of 
the  sap. 

"  My  letter  has  grown  to  a  most  immoderate  length,  and  I 
therefore  will  not  at  present  trouble  you  with  further  observa- 


28  LIFE    OF 

tions.  If  you  think  there  is  any  prospect  of  my  being  right,  I 
will  endeavour,  in  the  course  of  this  autumn  and  next  spring,  to 
make  further  experiments  and  observations.  My  opinions  on 
this  subject  have  been  the  same  during  the  last  six  or  seven 
years,  but  I  have  lately  been  paying  much  attention  to  the 
cause  of  blights,  and  I  have  reason  to  believe  that  they  depend 
much  on  an  imperfect  and  irregular  supply  of  sap.  There  is 
one  species  of  blight,  the  mildew,  of  whose  nature  I  have 
satisfied  myself  during  the  last  month.  It  appears  to  me  to  be 
evidently  a  plant  of  the  cryptogamous  class,  as  you  have  pro- 
bably long  since  known,  with  oval  capsules  and  globular  seeds. 
You  were  so  kind  as  to  say  you  had  taken  some  copies  of  the 
paper  I  had  the  honour  to  address  to  you  in  the  spring.  I  will 
not  trouble  you  to  send  them  to  me,  but  I  shall  be  much  obliged 
to  you  if  some  time  in  the  autumn  you  will  send  a  copy  or 
two  to  Mr.  Felton,  who,  I  believe,  has  the  honour  of  your 
acquaintance.  He  is  Mrs.  Knight's  uncle,  and  requested  me  to 
send  him  a  copy. 

"  I  am,  dear  Sir, 

"  Your  much  obliged  obedient  servant, 

"  T.  A.  KNIGHT." 

SIR  JOSEPH  BANKS  IN  REPLY. 

"  Soho  Square,  April  10,  1800. 

"  MY  DEAR  SIR  : 

"  Your  very  interesting  letter  would  not  have  remained  so 
long  unanswered,  had  I  not  been  for  the  last  month  in  a  state 
of  persecution  from  the  multiplied  duties  of  my  new  station  in 
the  Committee  for  Trade.  I  have  seldom  had  a  day  to  spare : 
and  till  the  holy  days  relieved  me,  I  thought  I  should  never  again 
be  permitted  to  return  to  my  favourite  pursuits ;  and  during 
my  absence  from  London,  the  impossibility  of  consulting  some 
of  my  friends,  whose  opinions  upon  the  subject  of  the  circulation 
of  sap  I  have  been  used  to  rely  upon,  prevented  my  writing. 

"Whether  any  of  our  predecessors  may  have  been  better 
qualified  to  investigate  the  physiology  of  plants  than  you  are,  I 


THOMAS    ANDREW    KNIGHT,    ESQ.  29 

shall  not  decide  upon  ;  but  that  you  are  eminently  qualified  for 
such  undertakings  I  will  most  readily  declare.  Your  observa- 
tions and  experiments  are  all  new  to  me,  and  have  given  me 
infinite  pleasure.  I  have  only,  therefore,  to  request  a  conti- 
nuation of  your  friendly  communications,,  either  in  manuscript 
or  in  print,  as  you  may  think  fitting,  and  I  promise  you  I  shall 
receive  them  with  no  little  avidity. 

"  I  dare  not  venture  to  decide  on  the  ingenious  conclusions 
you  have  drawn  from  your  experiments  ;  they  are  so  wholly  new, 
and  so  much  beyond  the  usual  range  of  opinions.  I  observe, 
however,  that  Dr.  Darwin,  who  mixes  truth  and  falsehood, 
ingenuity  and  perversity  of  opinions,  exactly  in  the  manner  we 
mix  the  ingredients  of  punch,  has  gone  beyond  your  speculation 
of  a  nervous  system  in  plants,  by  suggesting  that  they  may  have 
a  brain.  I  confess,  also,  that  he  does  not  follow  up  his  assertion 
with  half  the  force  of  reason  which  you  adduce  in  support  of  yours. 

"  Nothing  appears  to  me  likely  to  develope  the  internal 
structure  of  plants  so  much  as  the  analogy  they  bear  to  animals, 
whose  structure  is  more  easily  examined :  nature  seems  in 
organic  bodies  to  have  followed  one  uniform  plan ;  that  is,  she 
has  arranged  a  certain  number  of  parts  necessary  for  the 
structure  of  the  most  perfect  work  of  creation,  and  varied  her 
works,  principally  by  subtracting  something  from  each,  from 
the  man  to  the  mushroom,  which  is  like  a  man  furnished  with 
lacteals  in  the  form  of  roots,  but  has  no  occasion  for  a  stomach, 
or  for  the  powers  of  digestion. 

"  Plants  have  no  digestive  powers  :  and  putrefaction  appears 
to  me  to  do  the  office  for  plants  which  digestion  performs  for 
animals,  by  assimilating  the  parts  of  substances  that  have  been 
animal  or  vegetable  ;  both  feed  alike  on  what  has  at  some 
former  period  been  organized,  and  on  nothing  else. 

"  I  hope  you  will  not  disappoint  us  after  the  hopes  you  have 
given  us  of  a  visit  this  spring.  We  shall  be  in  high  beauty  very 
soon.  Kew  gardens  will  be  beautiful  in  a  fortnight's  time. 

"  Believe  me,  my  dear  Sir, 

"  With  sincere  esteem  and  regard,  most  faithfully  yours, 

"JOSEPH  BANKS." 


30  LIFE    OF 

Among  the  numerous  societies  to  which  the  present  age  has 
given  birth,  none,  perhaps,  have  been  followed  by  more  benefi- 
cial results  to  the  community  at  large  than  the  Horticultural 
Society.  The  proposed  establishment  of  this  society  was  first 
communicated  to  Mr.  Knight  by  Sir  Joseph  Banks,  as  follows : 

"  Soho  Square,  March  29,  1804. 

"  MY  DEAR  SIR  : 

"  It  having  occurred  to  some  of  us  here,  that  a  Horticultural 
Society  might  be  formed,  upon  a  principle  not  very  dissimilar 
from  that  of  the  numerous  Agricultural  Societies,  which,  if  they 
have  done  no  other  service,  have  certainly  wakened  a  taste  for 
agriculture,  and  guided  the  judgments  of  those  who  wished  to 
encourage  it ;  two  meetings  have  been  held  in  order  to  com- 
mence the  establishment,  the  proceedings  of  which  I  enclose  to 
you.  You  will  see  that  I  have  taken  the  liberty  of  naming  you 
as  an  original  member." 

John  Wedge  wood,  Esq.,  was  the  first  projector,  and  on  the 
society  being  constituted  on  the  14th  of  March,  1804,  the  rules 
and  regulations  which  had  been  suggested  by  Mr.  Wedgewood 
were  adopted.* 

On  the  30th  of  March,  a  meeting  was  held  for  the  appoint- 
ment of  an  annual  council  and  officers,  when  the  Earl  of  Dart- 
mouth was  elected  President,  Mr.  Wedgewood,  Secretary,  &c. 

The  first  part  of  the  Transactions  was  published  in  1807- 
It  opens  with  an  introductory  paper  written  by  Mr.  Knight, 
and  also  contains  another  paper  from  his  pen,  "  On  Raising 
New  and  Early  Fruits;"  read  November  4,  1806.  From  this 
time  every  succeeding  part  of  the  Society's  Transactions 
contain  several  communications  from  him. 

In  order  to  put  the  Society  upon  a  more  firm  foundation, 
and  to  give  it  a  higher  character,  both  in  this  and  foreign 
countries,  it  was  determined  to  obtain  a  charter,  which  was 

*  The  account  here  given  of  the  origin  and  progress  of  the  Horticultural 
Society  is  extracted  from  a  communication  from  the  Secretary,  Mr.  Bentham. 


THOMAS    ANDREW    KNIGHT,    ESQ.  31 

granted  in  April  1808,  and  on  Lord  Dartmouth  dying,  about 
the  end  of  the  year  1810,  Mr.  Knight  was  elected  President  on 
the  1st  of  January,  1811,  and  continued  to  fill  that  office 
during  the  remainder  of  his  life.  His  residence  in  the  country 
prevented,  indeed,  his  usually  taking  a  part  in  the  deliberations 
of  the  council ;  but  it  enabled  him  more  effectually  to  promote 
the  objects  of  the  Society,  by  the  prosecution  of  his  investiga- 
tions ;  and  on  every  occasion  where  his  time  or  his  purse  could 
be  made  available  to  its  interests,  his  assistance  was  always 
most  liberally  given.  With  one  or  two  exceptions,  he  was 
present  at  the  anniversary  meetings  on  the  1  st  of  May,  till  the 
last  year  of  his  life. 

At  the  period  when  Mr.  Knight  became  President,  the 
Society  had  made  little  progress ;  and  its  rapid  increase  after- 
wards is,  in  a  great  measure,  to  be  attributed  to  Mr.  Sabine,  who 
became  a  member  about  the  same  time,  and  afterwards  accepted 
the  office  of  secretary,  and  whose  zeal  and  activity,  supported  by 
the  reputation  of  the  President,  gave  a  new  impulse  to  its  exer- 
tions, and  enlisted  among  its  supporters  not  only  men  of  science 
and  practical  gardeners,  but  nearly  all  the  rank  and  wealth  of 
the  kingdom.  With  the  ample  means  thus  placed  at  the  dis- 
posal of  the  Society,  information  and  produce  were  collected 
from  all  parts  of  the  world,  and  were  distributed  with  unsparing 
liberality ;  and  by  the  sound  physiological  principles  taught  by 
the  President,  and  the  unceasing  activity  of  the  Secretary,  a 
complete  revolution  was  effected  in  the  science  and  practice  of 
gardening,  and  a  great  public  benefit  was  conferred  throughout 
the  kingdom,  by  inducing  many  in  every  class  of  life  to  employ 
their  leisure  hours  in  an  innocent  and  healthy  pursuit. 

The  Society  first  established  a  small  experimental  garden  at 
Kensington  in  the  commencement  of  the  year  1818  ;  but  this 
being  found  too  limited,  and  too  much  within  the  influence  of 
the  London  atmosphere,  it  was  determined  to  select  another  site, 
and  the  present  garden  of  thirty- three  acres  was  taken  a  few  years 
afterwards,  and  the  stock  finally  removed  there  in  the  early  part 
of  the  year  1 822.  The  great  expense  attending  the  establishment* 


32  LIFE    OF 

and  keeping  up  of  so  large  a  garden,  together  with  the  failure 
of  the  parliamentary  grant  and  the  royal  subscription,  both  of 
which  the  Society  had  been  led  to  expect,  but  which  it  never 
received,  added  to  some  losses  which  it  sustained  a  few  years 
afterwards,  gave  a  temporary  check  to  its  means  ;  but  the 
active  support  of  its  many  zealous  friends  enabled  it  to  recover 
its  position,  without  contracting  for  a  moment  the  field  of  its 
usefulness,  and  long  before  his  death,  Mr.  Knight  could  safely 
contemplate  this  society  as  a  permanent  means  of  applying  to 
the  benefit  of  the  community  those  physiological  principles 
which  he  had  laboured  through  life  to  establish. 

One  of  the  earliest  means  adopted  by  the  council  for  promot- 
ing the  improvement  of  horticulture,  was  the  establishment  of 
medals  as  a  reward  for  merit ;  these  were  first  given  in  the  year 
1808,  and  on  the  1st  of  May,  1814,  the  gold  medal  was  voted 
by  the  Society  to  Mr.  Knight,  "  For  his  various  and  important 
communications  to  the  Society,  not  only  of  papers  printed  in 
their  Transactions,  but  of  grafts  and  buds  of  his  valuable  new 
fruits." 

A  few  years  later,  the  council  thought  it  desirable  to 
establish  a  class  of  medals  of  a  smaller  size  than  the  original 
ones;  and  soon  after  the  death  of  Sir  Joseph  Banks,  in  1819, 
on  carrying  this  resolution  into  effect,  they  embraced  this 
opportunity  of  recording  their  sense  of  the  benefits  the  Society 
had  derived  from  his  support  and  influence,  by  calling  it  the 
Banksian  Medal,  and  placing  Sir  Joseph's  profile  on  the  obverse 
of  the  medal. 

In  the  year  1835,  in  consequence  of  the  extensive  distribution 
of  these  medals,  the  dies  had  become  worn  out ;  at  the  same 
time,  the  encouragement  to  horticulturists  which  they  had  given 
had  been  so  manifest,  that  it  was  determined  to  have  three  dies 
prepared  by  one  of  the  first  artists  of  this  country.  An  emble- 
matic representation  of  Flora,  attended  by  the  four  Seasons,  was 
selected  as  the  design  for  the  large  medal ;  the  head  of  Sir  Joseph 
Banks  was  again  adopted  for  the  smaller  one  ;  and  for  the  inter- 
mediate one,  the  council  determined  that  no  device  could  be 


THOMAS    ANDREW    KNIGHT,    ESQ.  33 

more  appropriate,  and  at  the  same  time  more  acceptable  to 
those  whom  it  was  intended  to  encourage,  than  a  similar  profile 
of  Mr.  Knight.  The  die  of  the  Knightian  medal  was  accordingly 
executed,  together  with  the  two  others,  by  Mr.  Wyon,  and  was 
first  distributed  to  those  to  whom  it  had  been  awarded  in  the 
course  of  the  year  1837.  At  a  meeting  of  the  Society  held  on 
the  4th  of  May,  1836,  it  was  resolved,  "  That  the  first  impres- 
sion of  the  Society's  new  large  medal  be  struck  in  gold,  and 
presented  to  Thomas  Andrew  Knight,  Esq.,  for  the  signal 
services  he  has  rendered  to  horticulture  by  his  physiological 
researches."  This  resolution  having  been  transmitted  to  Mr. 
Knight,  he  signified  his  acceptation  of  it  in  the  following  letter, 
characterised  by  that  liberality,  which  he  showed  in  all  his 
transactions  with  the  Society  : — 

"May  6,  1836. 

"My  DEAR  SIR, 

"  I  feel  highly  honoured  and  flattered  by  the  wishes  of  the 
members  of  the  Horticultural  Society  of  London,  that  the  first 
impression  of  their  new  gold  medal  should  be  presented  to  me, 
and  I  shall  receive  it  with  very  great  pleasure,  provided  I  be 
permitted  to  subscribe  a  sum  equivalent  to  its  cost,  to  be 
employed  in  liquidation  of  the  debt  of  the  Society,  but  not  upon 
any  other  conditions. 

"  I  remain,  &c., 

"T.  A.  KNIGHT. 
"  George  Bentham,  Esq.,  Secretary." 

From  the  preceding  details,  relating  to  the  establishment  and 
progress  of  a  Society  so  intimately  connected  for  many  years 
with  Mr.  Knight,  we  now  resume  the  thread  of  the  narrative  in 
noticing  his  pursuits  and  occupations  in  the  country. 

In  the  spring  of  1809,  Mr.  Andrew  Knight  and  his  family 
quitted  Elton  and  removed  to  Downton  Castle,  which  Mr.  Payne 
Knight  had  given  up  to  his  brother,  having  built  himself  a 
cottage  in  the  grounds,  in  which  he  passed  his  mornings  during 
the  summer  and  autumn  months  ;  the  rest  of  the  year  he  spent 

D 


34  LIFE    OF 

in  London.  He  still  received  his  visitors  at  the  castle,  and  fre- 
quently joined  the  family  party  at  dinner,  or  in  the  evening, 
and  the  arrangement  probably  contributed  to  the  comfort  of  all 
parties  ;  for  while  it  relieved  the  elder  brother  from  the  trouble 
unavoidably  attendant  on  a  large  country  establishment  to  a 
bachelor,  it  afforded  many  advantages  to  Mr.  Andrew  Knight 
and  his  family. 

Different  as  were  the  characters  and  dispositions  of  the 
brothers,  the  most  perfect  good  understanding  and  kind  feelings 
invariably  subsisted  between  them  ;  and  on  the  death  of  Mr. 
Payne  Knight,  in  May,  1824,  his  loss  was  acutely  felt  by  his 
brother. 

The  subjects  to  which  Mr.  A.  Knight  chiefly  devoted  his 
attention  at  this  period  will  be  seen  by  a  reference  to  his  writ- 
ings. It  is  a  source  of  regret  that  not  many  of  his  private 
letters  to  his  friends  have  been  preserved  which  would  have  any 
interest  for  the  general  reader,  but  a  few  will  be  given  in  this 
place. 

To  JOHN  WILLIAMS,  ESQ.,  PITMASTON. 

"  Elton,  1807. 


DEAR  SIR, 

"  I  had  sooner  written  to  thank  you  for  the  information  with 
which  you  have  provided  me,  respecting  your  improved  method 
of  managing  vines,  but  that  I  was  from  home  till  some  days 
after  your  letter  arrived  here,  and  I  have  subsequently  been 
every  day  necessarily  engaged  much  more  than  suits  my  eyes, 
which  do  not  bear  very  close  application. 

"  We  have  long  known  that  pears  can  live  on  branches  from 
which  a  portion  of  bark  is  taken  in  a  ircle  ;  but  this  operation 
has  always  been  injudiciously  performed,  and  the  improvement 
you  mention  is  certainly  your  own.  The  effect  of  taking  off  a 
circle  of  bark  is  to  occasion  a  stagnation  of  the  descending  sap, 
which  is  probably  repelled  back  into  the  buds  and  fruit,  and 
occasions  the  one  to  turn  into  blossom-buds,  and  supplies  the 


THOMAS    ANDREW    KNIGHT,    ESQ.  35 

other,  in  your  experiments,  with  a  more  abundant  portion  of 
food  than  it  would  otherwise  obtain ;  and  I  have  shown  that 
the  wood  of  a  fir-tree  above  such  a  decorticated  space,  was  one- 
fifth  larger  than  the  wood  of  the  same  tree  below :  the  specific 
gravity  of  the  one  being  0.590,  and  that  of  the  other  only  0.491. 
Your  experiment,  like  the  preceding,  which  is  in  the  Philoso- 
phical Transactions,  of  1806,  affords,  I  think,  strong  evidence 
in  support  of  my  theory,  in  which  the  sap  is  supposed  to  descend 
down  the  bark ;  and  on  that,  as  well  as  other  accounts,  is  very 
acceptable  to  me. 

"  I  had  occasion  to  write  to  Sir  Joseph  Banks  the  day  after 
I  came  home,  and  I  sent  him  an  account  of  your  experiments 
on  the  vine,  with  which  I  am  sure  he  will  be  much  pleased.  I 
think  an  account  of  them  would  be  very  well  received  by  the 
Horticultural  Society*.  I  feel  greatly  interested  in  them,  I 
assure  you,  both  as  a  gardener  and  as  they  afford  strong  evidence 
in  support  of  my  opinions  respecting  the  circulation  of  the  sap. 

"  I  remain,"  &c. 

The  two  letters  that  follow  relate  to  some  experiments  on  the 
effects  of  voltaic  electricity  on  vegetable  life,  which  Mr.  Williams 
had  undertaken  at  the  suggestion  of  Sir  Joseph  Banks  and  Mr. 
Knight,  whose  attention  had  been  directed  to  this  subject,  by 
experiments  made  by  Dr.  Wilson  Philip,  proving  the  powerful 
influence  of  a  current  of  electrical  fluid  when  applied  to  the 
digestive  organs  of  animals  ;  while  by  some  other  writers  it  had 
been  denied  that  any  effect  was  produced  by  similar  application 
of  electricity. 

Some  seeds  of  the  J^iciafaba  were  subjected  by  Mr.  Williams 
during  the  process  of  germination  to  a  current  of  voltaic  elec- 
tricity, and  the  result  was,  that  vitality  was  quickly  destroyed 
by  a  strong  charge  ;  and  that  even  the  slightest  that  could  be 
given  produced  a  manifestly  injurious  effect  on  the  plant,  and 
destroyed  it  when  long  persisted  in.  One  remarkable  effect 

*  A  paper  on  "  A  method  of  hastening  the  maturation  of  grapes,"  was  com- 
municated to  the  Horticultural  Society  by  Mr.  Williams,  May  3,  1808. 

D  2 


36  LIFE    OF 

apparent  was,  that  when  the  radicle  ceased  to  vegetate,  it  did 
not  change  colour  like  a  decaying  root  from  end  to  end,  but  in 
alternate  rings  of  black  and  white.  Mr.  Williams  thought  this 
effect  probably  indicated  that  some  parts  of  the  organization  of 
the  root  were  more  susceptible  of  the  electrical  influence  than 
others,  but  considered  that  it  deserved  further  investigation. 

/ 
"January  3,  1818. 

"  MY  DEAR  SIR, 

"  I  have  had  so  much  writing  on  my  hands,  that  I  had  not 
at  once  eyes  and  time  to  write  to  you  sooner,  which  must  plead 
my  excuse  for  my  apparent  inattention. 

"  The  metallic  oxydes  still  stand,  I  think,  too  prominent ; 
and  I,  if  I  had  not  seen  the  experiment,  should,  as  a  member 
of  the  Royal  Society,  on  hearing  the  paper  read,  be  more  dis- 
posed to  attribute  the  death  or  sickness  of  the  plants  to  the 
operation  of  metallic  poison,  than  to  the  voltaic  battery.  No 
one  can  possibly  rob  you  of  the  discovery  you  have  made,  as  my 
correspondence  with  Sir  Joseph  Banks  upon  the  subject  will 
prove.  You  will,  I  hope,  still  appear  in  the  same  part  of  the 
Transactions*. 

"  I  think  it  expedient  that  a  few  more  experiments  be  made, 
as  soon  as  you  begin  to  warm  your  vinery.  There  can  be  little 
difficulty  in  proving  whether  oxyde  of  iron,  that  is,  the  red 
oxyde,  which  I  suppose  to  be  the  kind  produced  by  the  voltaic 
battery,  is  poisonous  to  plants,  by  putting  a  dozen  rusty  nails 
into  a  tumbler  of  water  with  plants.  I  am  of  opinion  that  it 
would  not  produce  the  least  injury ;  for  red  soils  (which  are 
much  more  fertile  than  pale  yellow  and  white)  contain  about 
thirteen  per  cent,  of  red  oxyde,  and  plants  are  well  known  not 
to  be  destroyed  by  strong  chalybeate  springs. 

"  Many  beans  may  be  placed  over  a  tumbler  of  water,  with 
their  radicles  descending  into  the  water,  through  which  a  strong 
stream  of  galvanic  electricity  may  be  made  to  pass,  as  in  your 

*  Mr.  Williams'  paper  was  read  before  the  Royal  Society,  but  was  not 
printed  in  the  Transactions. 


THOMAS    ANDREW    KNIGHT,    ESQ.  37 

experiment  with  sprigs  of  mint,  when  I  had  the  pleasure  of 
being  at  Pitmaston  last. 

"  I  think  some  of  the  facts  you  mention,  not  being  important, 
had  better  be  omitted ;  for  short  papers,  like  short  sermons  to 
most  congregations,  are  more  agreeable  to  the  members  of  the 
Royal  Society,  some  of  whom  come  there  with  rather  a  strong 
propensity  to  fall  asleep  :  there  is  also,  among  philosophers  of 
the  present  day,  a  belief  that  the  electric  fluid  produced  little 
or  no  effect  upon  animal  or  vegetable  life  ;  and  to  oppose  this 
belief  strong  facts,  and  those  few  in  number,  being  most  easily 
remembered  and  weighed,  act  most  powerfully ;  and  every  fact 
which  is  not  really  strongly  in  favour  operates  injuriously. 

"  The  winter  has  set  in  rather  severely,  notwithstanding  the 
dispersion  of  arctic  ice  ;  but  we  must  not  decide,  till  we  have 
seen  a  few  springs,  upon  its  operation  in  chilling  our  climate. 

"  Sincerely  yours, 

"THOMAS  A.  KNIGHT." 

To    THE    SAME. 

"  Downton,  January  21,  1818. 
"  MY    DEAR  SlR, 

"  I  have  been  some  time  from  home  or  I  should  have  written 
to  you  sooner  upon  the  subject  of  your  paper.  I  am  myself 
perfectly  satisfied  that  your  conclusions  respecting  the  influence 
of  the  voltaic  battery  upon  plants  are  correct ;  but  the  opposite 
opinion  that  the  electric  fluid  produces  no  effect  upon  vege- 
table being,  has  got  possession  of  the  public  mind,  owing  to 
erroneous  conclusions  having  been  drawn  by  former  writers, 
who  had  imagined  themselves  to  have  witnessed  the  influence 
of  electricity  to  be  great  in  promoting  the  growth  of  plants. 
Your  paper  must  therefore  come  before  judges  who  have  already 
drawn  conclusions  in  direct  opposition  to  yours.  My  wishes  rela- 
tive to  your  paper  can  point  to  one  object  only,  which  is  that  of 
doing  you  credit ;  and  I  fear  that  unless  strong  evidence  can  be 
made  to  meet  the  possibility  of  the  operation  of  metallic  oxydes, 
Sir  Joseph  Banks  would  request  you  to  delay  its  presentation  to 


38  LIFE    OF 

the  Royal  Society.  I  have  had  a  correspondence  with  him  upon 
the  subject ;  and  I  see  that  the  erroneous  conclusions-  which 
have  been  drawn  relative  to  the  influence  of  common  electricity 
upon  plants,  have  made  a  strong  impression  upon  his  mind. 

"  Relative  to  climate  :  the  public  attention  is  at  the  present 
moment  pointedly  directed  to  the  important  fact  of  the  disper- 
sion of  the  enormous  collection  of  ice  in  the  North,  to  which 
Sir  Joseph  Banks,  and  probably  almost  every  philosopher,  who 
has  directed  his  attention  to  the  subject,  has  attributed  an  inti- 
mate connexion  with  our  cold  weather  in  the  spring  ;  and  con- 
sequently this  is  the  precise  moment  in  which  an  amelioration 
of  our  spring  weather  from  these  causes  is  anticipated ;  therefore 
it  is  a  bad  moment  for  a  paper,  attributing  the  change  in  our 
climate  to  local  causes,  to  appear  before  the  Royal  Society. 

"  France,  you  know,  has  made  very  little  good  wine  for 
several  years,  yet  no  change  of  culture  has  taken  place  in 
France  likely  to  influence  the  temperature  of  its  climate  within 
the  last  seventy  years  ;  and  the  fact  that  Europe  has  grown 
milder  by  the  destruction  of  its  forests,  appears  to  be  universally 
admitted.  I,  however,  make  these  remarks  merely  for  your 
consideration,  and  am  ready  to  act  just  as  you  wish  me  to  do. 

"  Mrs.  Knight  and  my  daughters  beg  to  be  kindly  remembered 
to  Mrs.  Williams  and  family. 

"  Yours  sincerely." 


To  ONE  OF  HIS  DAUGHTERS. 

"May  2,  1826. 
"MY    DEAREST    F , 

"  Our  meeting  passed  off  as  usual  yesterday,  and  the  apparent 
feeling  of  the  members  was  so  friendly  that  I  could  almost  call 
it  affectionate.  I  said  a  few  words  to  them  respecting  the  mag- 
nitude and  increased  importance  of  the  Society,  and  suggested 
the  consideration  whether  the  office  of  president  ought  not  to 
be  held  by  a  person  of  higher  rank  and  consequence  than  myself, 
and  requested  that  whenever  it  appeared  to  them  that  a  bene- 


THOMAS  ANDREW  KNIGHT,  ESQ.  39 

ficial  change  of  president  might  take  place,  no  tenderness  of 
feeling  towards  me  ought  to  influence  them  ;  and  that  whether 
I  continued  my  office  of  president,  or  became  an  ordinary 
member  of  the  Society,  my  best  exertions  should  never  be  want- 
ing to  support  its  prosperity.  I  was  much  cheered,  and  I 
believe  the  wish  that  I  should  continue  my  office  is  generally 
entertained  by  the  Society  ;  so  I  suppose  I  am  likely  to  continue 
P.  H.  S. 

"  We  have  just  received  from  the  North-west  coast  of  America 
from  one  of  our  collectors,  named  Douglas,  a  large  collection 
of  seeds  of  plants,  amongst  them  some  of  a  new  species  of  rasp- 
berry, of  much  merit,  of  which  I  had  before  heard  ;  and  of  a 
most  beautiful  plant  of  the  genus  Gualteria,  which  is  allied  to 
the  Vacciniums,  but  bears  a  very  close  resemblance  to  an 
Arbutus,  and  flourishes  in  the  deepest  shade,  even  that  of  a  dense 
pine-forest ;  and  is  perfectly  hardy.  Its  fruit  is  also  sweet  and 
palatable,  and  Mr.  Douglas  told  me  that  he  had  lived  wholly  upon 
it  for  three  days  and  a  half ;  but  as  a  shrub  it  is  thought  a  great 
acquisition  indeed.  I  shall  bring  down  some  seeds  of  it,  and  I 
hope  to  raise  many  plants,  some  for  you. 

"  Our  collector  proposes,  when  he  has  sent  all  he  can  home 
by  a  ship,  to  march  across  the  continent  of  America  to  the 
country  of  the  United  States  on  this  side,  and  to  collect  what 
plants  and  seeds  he  can  in  his  journey  ;  but  it  is  but  too  pro- 
bable that  he  will  perish  in  the  attempt.  Mr.  Sabine  says,  that 
if  he  escapes,  he  will  soon  perish  in  some  other  hardy  enter- 
prise or  other*.  It  is  really  lamentable  that  so  fine  a  fellow 
should  be  sacrificed.  He  is  the  shyest  being  almost  that  I  ever 
saw  ;  and  upon  my  requesting,  the  year  before  the  last,  to  ask 
him  some  questions  respecting  a  part  of  America  through  which 
he  had  travelled,  Mr.  Sabine  said  '  Now  Douglas  will  be  terribly 
frightened  ;'  and  so,  with  all  his  daring  personal  courage  as  to 

*  This  prophecy  was  unhappily  fulfilled  only  a  few  years  afterwards  by  the 
deatk  of  Mr.  Douglas,  who,  while  exploring  the  mountains  in  the  interior  of 
Owhree,  one  of  the  Sandwich  Islands,  fell  into  a  pit  constructed  for  taking  wild 
cattle,  and  was  gored  to  death  by  a  bull,  which  had  previously  been  captured. 


40  LIFE    OF 

actual  danger,  he  appeared  to  be,  till  I  had  talked  to  him  for 
some  time  in  a  friendly  and  familiar  way.  With  very  kind 
remembrances  to  all, 

"  Ever  your  affectionate  father." 

In  the  summer  of  1827,  Mr.  Knight  had  the  gratification  of 
receiving  a  visit  from  Monsieur  Dutrochet,  with  whom  he  had 
long  held  an  intercourse  by  letter,  though  they  had  not  previ- 
ously met.  The  extract  given  below  from  a  letter  to  Mr. 
Williams,  relates  to  this  visit; 

"  We  came  here  (Downton)  from  London  in  a  single  day,  or 
we  should  have  had  great  pleasure  in  spending  a  day  at  Pit- 
maston.  I  brought  with  me  my  French  correspondent,  Mons. 
Dutrochet,  who  I  mentioned  to  you  as  the  discoverer  of  the  extra- 
ordinary circumstance  that  animal  and  vegetable  membrane, 
which  under  ordinary  circumstances  are  impervious  to  water, 
readily  admit  that  fluid  to  pass  through  them  when  their  oppo  - 
site  sides  are  in  contact  with  a  fluid  of  greater  density,  or  in  some 
instances  possessing  different  chemical  powers  ;  and  the  facts 
he  had  advanced  render  it  doubtful  whether  any  mechanical 
agent  is  at  work  in  raising  the  sap  in  trees,  except  the  mem- 
brane, which  separates  the  cells  from  each  other,  which  are 
excited  to  act  by  some  power,  probably  chemical,  in  the  sap. 
M.  Dutrochet  spent  a  fortnight  here,  during  which  we  made 
some  experiments  together,  and  investigated  the  hypotheses  of 
different  writers.  He  travelled  550  miles,  and  back  again,  with 
no  further  object  than  to  have  an  opportunity  of  conversing 
upon  the  subject  of  vegetable  physiology.  I  found  him  a  very 
intelligent  and  generally  well  informed  man,  and  he  returned  a 
very  zealous  horticulturist.  The  inhabitants  of  his  vicinity,  the 
neighbourhood  of  Tours,  appear  to  be  extremely  ignorant  of 
horticulture,  and  to  know  nothing  of  varieties  of  fruit  of  any 
kind  beyond  those  described  by  Duhamel." 

Mr.  Knight's  time  was  divided  between  philosophical  and 
horticultural  investigations,  and  the  fulfilment  of  the  duties  of 
a  country  gentleman.  He  had  ceased  to  occupy  any  land  him- 


THOMAS    ANDREW    KNIGHT,    ESQ.  41 

self,  but  he  paid  great  attention  to  the  cultivation  of  his  estate 
by  his  tenantry ;  and  though  he  was  on  all  occasions  a  most 
liberal  and  indulgent  landlord,  and  ever  ready  to  afford  encou- 
ragement and  assistance  to  active  and  intelligent  tenants,  he 
was  firm  in  insisting  on  the  adoption  of  a  proper  course  of 
management. 

He  was  happy  in  his  home,  and  beloved  by  all  about  him  ;  and 
his  healthful  and  peaceful  occupations,  while  they  supplied 
never-ceasing  employment  for  his  active  mind,  kept  him  free 
from  the  mortifications  and  disappointments  which  are  too  fre- 
quently attendant  on  a  life  of  public  service,  or  a  course  of 
ambition. 

On  the  29th  of  November  1827,  Mr.  Knight  was  unhappily 
called  upon  to  sustain  the  heaviest  affliction  that  can  fall  on  a 
father,  in  the  death  of  his  only  son,  by  a  blow  as  unexpected  as 
it  was  overwhelming. 

The  following  account  of  this  singularly  promising  young 
man,  extracted  from  a  memoir  written  by  one  of  his  friends* 
soon  after  his  death,  will  show  as  far  as  words  can  do,  how  irre- 
parable was  the  loss  of  such  a  son  and  brother,  to  a  family 
whose  hearts  were  only  too  strongly  fixed  upon  him. 

"  The  dreadful  accident  which  cut  off  in  the  prime  of  life  an 
only  son,  and  one  who  was  even  less  the  object  of  the  admira- 
tion of  his  family  for  his  talents  than  he  was  of  their  affection 
for  his  amiable  qualities,  took  place  at  his  father's  house 
on  the  29th  of  November,  1827-  Mr.  Knight  was  shooting,  in 
the  company  of  two  gentlemen,  in  the  woods  at  Downton 
Castle,  when  a  casual  shot  struck  him  in  the  eye,  and  passed 
into  the  brain.  He  met  the  blow  with  fortitude  and  resigna- 
tion— not  a  reproach  escaped  him.  He  was  immediately  con- 
veyed to  an  adjoining  cottage,  where  he  soon  fell  into  a  state 
of  insensibility,  having  exerted  himself,  as  long  as  his  faculties 
remained  to  him,  in  endeavouring  to  alleviate  the  misery  of  his 
unfortunate  companion  who  had  inflicted  the  blow.  Medical 

*  The  Rev.  Thomas  Salwey,  Vicar  of  Oswestry. 


42  LIFE    OF 

aid  was  soon  procured ;  but  it  was  a  case  that  no  human  art 
could  reach.  He  lingered  until  about  ten  o'clock  on  the  following 
morning,  when  he  expired,  apparently  without  pain — the  only 
circumstance  which  could  shed  a  gleam  of  consolation  over  the 
agony  of  those  hours  during  which  his  afflicted  relatives  watched 
over  him. 

"  In  drawing  a  brief  sketch  of  this  lamented  young  man,  we 
feel  that  we  cannot  better  describe  him  than  by  saying,  that  he 
combined  in  a  remarkable  manner  the  talents  of  his  uncle  and 
his  father,  whose  names  have  long  been  familiar  to  the  literary 
and  scientific  world,  both  at  home  and  abroad;  the  former 
having  been  justly  regarded  as  one  of  the  most  distinguished 
scholars,  the  latter  as  one  of  the  first  physiologists  of  his  age. 

"The  reputation  of  his  uncle,  and  his  own  education  at  Eton, 
had  led  him  to  become  intimately  acquainted  with  the  classics ; 
and  one  of  the  highest  gratifications  which  his  intimate  friends 
derived  from  his  society  arose  from  that  keen  perception  of 
their  beauties  which,  with  the  aid  of  a  powerful  memory, 
enabled  him  so  happily  to  apply  them  to  passing  scenes. 

"From  Eton  he  removed  to  Trinity  College,  Cambridge, 
where  he  made  a  considerable  progress  in  mathematics.  He 
became  also  well  acquainted  with  metaphysics,  a  branch  of 
knowledge  in  which  he  took  much  pleasure.  It  has  been  ob- 
jected to  metaphysics  that  they  lead  to  scepticism ;  but  they 
whose  originality  of  mind  leads  them  to  seek  for  truth  in  new 
and  unbeaten  tracks,  where  few  are  capable  of  following  them, 
are  perhaps  too  hastily  accused  of  disregarding  the  important 
truths  of  revelation.  Whatever  danger,  however,  may  arise 
from  the  study  of  metaphysics  to  less  powerful  minds,  the  sub- 
ject of  this  memoir  was  possessed  of  qualities  which  prevented 
his  being  long  misled  by  them.  To  a  patient  investigation  of 
truth,  and  that  jealousy  in  its  admission  which,  whilst  it  is  the 
mark  of  a  superior  mind,  is  at  the  same  time  the  ground  of  that 
confidence  we  place  in  its  decisions,  he  united  an  openness  to 
conviction,  and  a  candour  in  acknowledging  it,  that  few  are 
possessed  of.  Whilst  he  delighted  them  by  following  our 


THOMAS    ANDREW    KNIGHT,,    ESQ.  43 

deepest  metaphysicians  through  all  the  subtleties  of  their  inge- 
nious disquisitions,  his  intimate  friends  can  bear  testimony  that 
the  evidences  of  revealed  religion  had  latterly  occupied  much 
of  his  attention,  which  he  discussed  in  that  spirit  of  candour, 
and  with  that  fair  mode  of  argument,  which  can  alone  make 
our  faith  a  rational  one. 

"  There  were  few  branches  of  knowledge  into  which  the 
acute  mind  of  this  gifted  individual  had  not  led  him  ;  but  those 
in  which  he  took  most  delight  were  the  different  branches  of 
natural  history,  particularly  zoology,  ornithology,  and  botany. 
Few,  indeed,  at  his  age  have  possessed  a  mind  stored  with  such 
deep  and  varied  information ;  for  a  quickness  of  perception, 
carrying  him  at  once  through  all  the  ordinary  paths  of  know- 
ledge, made  him  appear  to  start  from  the  point  at  which  others 
rested  as  their  goal.  The  energy  of  a  powerful  mind  led  him 
at  once  to  cope  with  difficulties,  which  others  need  the  discipline 
of  habit  to  enable  them  to  encounter  with  success ;  hence  arose 
the  acquisition  of  a  deep  and  varied  store  of  information,  appa- 
rently without  effort  or  application. 

"  The  same  originality  of  mind,  which  made  him  delight  in 
pursuing  some  of  the  least  beaten  tracks  of  knowledge,  guided 
him  also  in  the  choice  of  his  travels.  It  was  to  those  countries 
on  the  Continent  of  Europe,  where  man  has  done  the  least  in  sub- 
duing nature,  that  he  bent  his  steps — Norway,  Sweden,  Lapland, 
and  Finmark,  became  the  field  of  his  researches.  Here,  in  the 
company  of  his  friend,  George  Chichester  Oxenden,  Esq.,  he 
encountered  difficulties  and  hardships  which  the  less  hardy 
frame  of  the  enterprising  Clarke  prevented  him  from  attempt- 
ing. Blessed  with  stronger  constitutions,  they  traversed  2^° 
of  latitude  between  Tornea  and  the  Icy  Sea,  principally  on 
foot,  carrying  their  own  provisions,  occasionally  exposed  to 
imminent  danger  from  the  half-frozen  state  of  the  lakes  and 
rivers  they  had  to  pass  over,  and  sleeping  for  many  nights 
together  on  the  snow.  They  at  length  reached  the  North  Cape, 
and  afterwards,  from  the  little  village  of  Hammerfest,  embarked 
on  board  a  Russian  trader  for  Archangel,  with  the  intention  of 


44  LIFE    OF 

wintering  at  Soroke,  in  the  Gulf  of  Kandalax,  but  the  vessel 
having  been  disabled  in  a  storm,  in  want  of  provisions,  and  the 
crew  in  a  state  of  insubordination,  they  were  compelled  to  leave 
her,  and  to  return  in  an  English  vessel  they  fortunately  fell  in 
with  in  the  White  Sea.  A  second  storm  obliged  them  to  run 
into  a  harbour  near  the  island  of  Hitteroen,  on  the  coast  of 
Norway.  Here  our  travellers  separated,  Mr.  Oxenden  return- 
ing home,  and  Mr.  Knight  proceeding  to  St.  Petersburg,  by  the 
way  of  Drontheim  and  Stockholm. 

"  Upon  his  return  to  his  native  country,  Mr.  Knight  sedu- 
lously devoted  himself  to  those  duties  which  have  raised  so  high 
the  character  of  the  English  country  gentleman.  As  an  impar- 
tial and  enlightened  magistrate  ;  as  a  zealous  and  liberal  patron 
of  public  improvements  ;  as  the  friend  and  protector  of  the 
poor ;  as  one  who  from  his  talents  was  destined  to  take  a  lead 
in  that  station  in  which  his  large  property  would  have  placed 
him ;  his  country,  and  the  county  of  Hereford  in  particular, 
will  long  lament  him.  A  refined  and  highly  principled  mind, 
and  a  natural  modesty  of  character,  had  already  gained  him  the 
esteem  of  a  large  circle  of  acquaintance ;  while  his  amiable  dis- 
position, and  his  attachment  to  his  relations,  which  indeed  was 
one  of  the  most  striking  features  of  his  character,  had  secured 
to  him  in  an  eminent  degree  the  affections  of  his  own  family 
and  of  his  friends. 

"  His  remains  were  interred  at  Wormsley,  in  the  county  of 
Hereford,  near  those  of  his  uncle ;  and  though,  in  compliance 
with  the  wishes  of  his  family,  his  funeral  was  strictly  private, 
the  regrets  of  a  whole  county  and  the  tears  of  the  poor  followed 
him  to  his  early  grave. 

"  Mr.  Andrew  Knight  was  born  on  the  23d  of  June,  1796, 
and  was  therefore  in  his  32d  year." 

A  belief  in  the  unerring  wisdom  by  which  the  affairs  of  this 
world  are  guided  and  directed,  was  so  firmly  impressed  in  Mr. 
Knight's  mind,  that  no  murmur  escaped  him,  at  the  mysterious 
dispensation  that  had  blasted  all  his  fondest  hopes.  He  soon 


THOMAS   ANDREW    KNIGHT,    ESQ.  45 

resumed  his  usual  occupations,  but  in  a  manner  from  which  it 
was  evident,  that  his  chief  object  was  to  endeavour  to  withdraw 
his  mind  from  a  contemplation  of  his  bereavement ;  but  the  plea- 
sure they  had  once  afforded  to  him  was  gone,  and  the  interest 
he  had  hitherto  taken  in  all  around  him,  was  now  converted 
into  a  painful  source  of  recollection. 

In  a  letter  to  a  friend  written  in  the  course  of  the  following 
year  he  says  : — 

"  I  am  at  present,  as  I  have  been  for  some  months,  not  in  a 
state  of  mind  to  attend  to,  or  interest  myself  about  anything. 
I  endeavour  all  I  can  to  rouse  myself  into  action,  and  I  trust  I 
shall  in  time  succeed ;  for  I  know  that  I  cannot  long  survive  in 
a  state  of  idleness. 

"  I  cannot  but  feel  consoled  and  gratified  by  the  interest 
taken  in  the  calamity  of  my  family  by  all  classes.  My  son,  if 
his  life  had  been  spared,  I  am  confident  would  have  fully  justi- 
fied the  favourable  opinion  generally  entertained  of  him.  As  a 
father,  he  never  gave  me  pain,  except  when  the  ardour  of  his 
character,  and  I  may  say  his  absolute  love  of  danger,  excited 
very  painful  apprehensions  in  my  mind.  The  ways  of  Provi- 
dence are  hid  from  our  sight,  but  the  rule  by  which  all  is 
guided  is  just,  and  life  is  at  best  but  an  uncertain  blessing,  and 
it  is  perhaps  weakness  to  mourn  for  the  dead." 

To  a  casual  observer  a  slight  appearance  of  nervous  excite- 
ment was  soon  the  only  symptom  that  indicated  the  change  this 
blow  had  made — but  to  those  who  lived  with  him,  and  were 
anxiously  watching  the  workings  of  his  mind,  the  fearful  strug- 
gle that  was  going  on  within,  was  painfully  apparent :  disap- 
pointment, nevertheless,  never,  for  one  moment,  had  power  to 
sour  the  sweetness  of  his  temper,  and  he  seemed  to  be  always 
trying  to  fill  the  blank  in  his  heart,  by  bestowing,  if  possible, 
redoubled  kindness  and  affection  upon  those  who  were  still 
spared  to  him. 

It  was  long  before  he  was  like  himself  again  ;  and  even  to  the 
close  of  his  life,  though  time  had  done  much  by  its  softening 


46  LIFE    OF 

influence  to  restore  his  mind  to  a  healthy  tone,  there  had  been 
impressions  made  under  the  first  overwhelming  influence  of  this 
blow.,  which  no  effort  of  reason,  nor  the  persuasions  of  those 
around  him,,  could  ever  entirely  eradicate.  The  following 
letter  from  Sir  Humphry  Davy  shows  how  warmly  he  sympa- 
thised in  Mr.  Knight's  affliction. 

"  Park  Street,  January  J7,  1828. 

"  MY  DEAR  SIR, 

"  I  have  three  or  four  times  within  the  last  six  weeks  taken 
up  the  pen  and  begun  to  write  to  you ;  but  I  have  always  laid 
it  down  again,  fearing  to  trust  myself  with  a  subject  on  which 
I  could  not  write  without  feeling  deeply,  and  great  mental 
agitation. 

"  I  have  grieved  with  you,  but  in  such  the  most  awful  visi- 
tation of  evil  belonging  to  human  nature,  it  is  almost  vain  to 
attempt  to  offer  consolation :  yet,  considering  life  as  a  great 
system  in  which  all  is  for  good,  and  believing  that  the  intellec- 
tual and  moral  part  of  our  nature  is  as  indestructible,  as  the 
atoms  that  compose  our  frame,  I  feel  the  conviction  that  where 
a  mind  so  highly  gifted,  and  so  little  selfish,  is  removed  from 
this  scene  of  being,  apparently  so  prematurely,  it  is  to  act  in  a 
better  and  nobler  state  of  existence. 

"  The  noblest  spirits  often  return  the  soonest  to  the  source 
of  intellectual  life,  from  which  they  sprung:  and  they  are 
surely  the  happiest ;  whilst  we  are  to  wait  the  trials  of  sorrow, 
sickness,  and  age. 

"  I  offer  my  most  ardent  wishes  for  your  recovery,  and  that 
of  Mrs.  Knight.  I  know  the  agony  ofspesfracta,  but  even  in  this 
case,  time,  the  great  soother,  creates  a  new  source  of  hope. 

"  I  wish  I  could  give  you  a  more  satisfactory  answer  to  your 
kind  inquiries  respecting  my  health.  Dr.  Philip  has  been  very 
kind  to  me,  but  '  my  body  does  me  sorely  wrong.'  I  some- 
times hope,  and  sometimes  despair,  of  ultimate  recovery.  My 
paralytic  symptoms  are  much  diminished :  but  still  I  cannot 
get  rid  of  stiffness  in  my  right  arm  and  leg.  I  am  now  amus- 


THOMAS    ANDREW    KNIGHT,    ESQ.  47 

ing  myself  with  inquiries  in  natural  history,  and  I  hope,  in  the 
spring,  to  make  some  inquiries  respecting  the  transmigrations 
of  some  of  the  anglers'  water-flies. 

"The  Gardens  of  the  Zoological  Society  are  flourishing, 
and  there  are  a  good  many  animals  collected  there. 

"  The  political  bark,  left  by  Mr.  Canning  without  a  pilot, 
seems  quite  wrecked ;  and  I  believe  there  will  be  some  diffi- 
culty in  building  another.  The  country  is  in  a  very  critical 
state ;  there  certainly  never  was  a  moment  in  which  less 
political  talent  appeared ;  but  I  am  writing  on  a  subject  which 
every  body  seems  to  be  alike  ignorant  of,  and  the  business  is, 
I  fear,  in  hands  weak  in  talent  though  strong  in  influence. — 
I  am,  my  dear  Sir, 

"  Very  sincerely  your  obliged  friend, 

"  H.  DAVY." 

The  full  measure  of  distress  brought  on  Mr.  Knight  by  his 
bereavement,  cannot  be  known  unless  it  be  mentioned,  that  in 
consequence  of  expressions  open  to  ambiguous  interpretation 
used  by  Mr.  Payne  Knight  in  his  will,  an  amicable  law-suit 
had  already  been  commenced  with  all  parties  interested.,  in  order 
that  the  right  succession  to  his  estates  might  be  determined. 

The  death  therefore  of  his  son,  to  whom  the  property  would 
unquestionably  have  descended,  made  this  already  painful  posi- 
tion tenfold  more  distressing  to  him ;  and  though  the  happy 
disposition  of  his  mind  to  look  on  the  bright,,  rather  than  the 
dark  side  of  the  prospect,  supported  him  through  the  remainder 
of  his  life,  the  uncertainty  in  which  he  continued  even  to  his 
death,  as  to  the  power  of  disposing  of  his  estates,  was  often  a 
source  of  anxiety  and  grief  to  him. 

Before  Sir  Humphry  Davy  quitted  England  for  the  last  time, 
he  published  a  fourth  edition  of  his  Lectures  on  Agricultural 
Chemistry,  which  he  dedicated  to  Mr.  Knight;  and  thus 
announced  it  in  a  letter  written  on  the  eve  of  his  departure, 
May  20th,  1828. 

•f  It  was  my  ardent  wish  to  pay  you  a  visit  before  I  left 


48  LIFE    OF 

England ;  but  I  do  not  feel  myself  sufficiently  strong.  I  must 
defer  it  till  another,  and  a  better  season.  The  extremely  severe 
course  of  diet  and  regimen  keeps  my  spirits  very  low,  and,  my 
physicians  tell  me,  this  is  absolutely  necessary;  and  whether  I 
live  or  die,  I  am  resolved  to  live  according  to  rule,  and  to  give 
my  constitution  a  fair  chance. 

"  I  have  sent  a  copy  of  my  Agricultural  Chemistry  to  the 
Horticultural  Society,  addressed  to  you.  If  any  thing  it  con- 
tains relating  to  Vegetable  Physiology  is  of  value,  it  is  owing 
to  you,  and  in  my  dedication  I  perform  at  once  an  act  of  public 
duty  and  of  private  friendship.  Should  I  recover  my  health, 
I  have  various  plans  of  scientific  labour,  principally  on  natural 
history :  and  in  the  wintry  state  of  my  mind,  I  live  principally 
on  hope.  I  beg  my  kindest  remembrances  to  Mrs.  Knight, 
and  all  your  family ;  and  I  am,  my  dear  Sir, 

"  Most  sincerely  yours, 
"  H.  DAVY." 

Sir  H.  Davy  died  at  Genoa,  on  the  28th  of  May,  1829.  Of 
all  Mr.  Knight's  friends,  there  was  not  one  in  whose  society  he 
so  much  delighted,  and  whom  he  could  so  ill  at  this  time  have 
spared :  there  were  many  points  in  which  the  feelings  of  both 
were  peculiarly  in  accordance.  They  were  both  impelled  by 
the  same  ardour  in  the  investigation  of  truth,  and  the  same 
desire  to  render  their  talents  and  their  labour  beneficial  to  their 
fellow-creatures . 

The  investigation  of  nature  in  all  the  various  forms  of 
creation,  was  a  source  of  delight  to  both  ;  and  the  keen  percep- 
tion of  the  charm  of  poetry,  which  Mr.  Knight  possessed  in  no 
common  degree,  caused  him  to  derive  the  highest  gratification 
from  the  singular  combination  of  poetic  imagery  with  deep 
philosophic  discussion,  which  often  characterized  Sir  H.  Davy's 
conversation. 

In  his  will,  Sir  H.  Davy  left  Mr.  Knight  a  seal  ring,  bearing 
the  impression  of  a  fish,  in  remembrance  of  the  days  passed 
together  on  the  banks  of  the  Teme. 


THOMAS    ANDREW    KNIGHT,    ESQ.  49 

Mr.  Knight  had  constantly  been  urged  by  his  horticultural 
friends  in  England,  and  on  the  Continent,  to  collect  all  he  had 
written  together,  to  publish  it  as  a  single  work ;  and  at  one  time 
he  entertained  serious  thoughts  of  commencing  a  labour  of  this 
kind ;  but  a  habit  of  procrastinating,  or  perhaps  it  may  be  more 
properly  said,  the  ardour  of  pursuit  which  constantly  impelled 
him  forward  to  seek  untrodden  ground,  made  the  task  of  working 
over  the  old  irksome,  and  hence  he  unfortunately  never  accom- 
plished this  desirable  object :  and  from  the  same  causes  he 
declined  to  write  articles  on  vegetable  physiology  for  the  Edin- 
burgh Encyclopaedia,  and  the  Society  for  the  Promotion  of 
Useful  Knowledge,  to  do  which  he  was  strongly  urged.  The 
subjoined  extract  from  a  letter  from  Monsieur  De  Candolle, 
shows  that  an  intention  of  translating  and  collecting  Mr. 
Knight's  papers  was  entertained  at  Geneva,  but  it  was  aban- 
doned in  consequence  of  Mr.  Knight  expressing  his  intention 
of  undertaking  the  task  himself. 

"  Geneve,  5  Juin,  1829. 

"  MON  CHER  MONSIEUR: 

"  Un  homme  que  vous  connoissez  peut-etre  de  reputation, 
M.  Le  Baron  Creed,  (qui  a  traduit  en  Fran9ois  Touvrage  de 
Thaer,)  passant  Thiver  a  la  campagne,  et  voulant  employer  les 
longues  soirees  d'hiver  a  quelque  chose  d'utile,  est  venu  me 
demander  de  lui  designer  quelque  ouvrage  a  traduire  :  je  lui  ai 
propose  de  traduire  et  de  re'unir  en  un  volume  tous  vos  divers 
memoires  sur  la  physiologie  vegetale  et  1'horticulture.  Ce 
plan  lui  a  souri,  mais  avant  de  le  mettre  a  execution  je  me 
suis  charge  de  vous  ecrire  pour  vous  demander — 1°.  Si  cette 
reunion  de  vos  divers  memoires  en  un  corps  d'ouvrage  ne  vous 
seroit  pas  desagreable,  et  si  vous  y  donnez  votre  consentement. 
2°.  Si  vous  vouliez  m'envoyer  la  liste  complette  de  vos  memoires, 
afin  que  nous  ne  risquions  pas  d'omettre  quelqu'un.  3°.  Si  dans 
le  cas  ou  vous  aviez  quelques  additions  ou  corrections  a  faire  a 
1'un  d'eux,  vous  voudriez  1'adresser  a  M.  Creed,  pour  qu'il 
Fajoutat  en  votre  nom ;  et  enfin  si  vous  vouliez  lui  permettre 
de  corresponds  avec  vous  pendant  la  duree  de  son  travail.  II 

E 


50  LIFE    OF 

attendra  votre  reponse  pour  entreprendre  son  travail.  Je  serois 
de  ma  part  charm  e  de  voir  reunis  des  memoires  d'un  si  grand 
interet,  et  qui  sont  a-present  dans  des  collections  si  volumi- 
neuses,  et  qu'on  n'a  pas  toujours  sous  la  main. 

"  Recevez,  mon  cher  Monsieur  et  collegue,  Fexpression  de 
la  haute  et  sincere  consideration  avec  laquelle  je  suis  votre 
humble  et  devoue  serviteur, 

"DE  CANDOLLE*." 

The  letters  which  have  been  hitherto  introduced  into  this 
memoir,  have  shown  the  kind  and  friendly  intercourse  which 
existed  between  Mr.  Knight  and  some  of  the  first  philosophers 
of  his  age.  In  order  to  do  full  justice,  however,  to  the  kind- 
ness of  his  heart,  we  trust  to  be  excused  for  exhibiting  his 
character  as  a  parent,  by  introducing  the  following  specimens 
of  his  correspondence  with  his  children ;  which  will  show  how 
vivid  even  in  advanced  age  was  his  sympathy  in  the  sufferings 
or  happiness  of  others,  and  how  unabated  the  warmth  of  his 
affections. 


*  "  MY  DEAR  SIR, 

"  A  man  whom  you  perhaps  know  by  reputation,  M.  le  Baron  Creed,  (who 
has  translated  into  French  the  work  of  Thaer),  is  going  to  pass  the  winter  in 
the  country,  and  being  desirous  to  employ  the  long  winter  evenings  in  some 
useful  occupation,  he  has  come  to  me  to  request  me  to  point  out  to  him  some 
work  to  translate.  I  have  proposed  to  him  to  translate,  and  to  unite  in  one 
volume,  your  various  papers  on  vegetable  physiology  and  horticulture.  He  ap- 
proves this  plan  ;  but  before  executing  it,  I  have  undertaken  to  write  to  you,  to 
ask,  first,  if  this  combination  of  your  different  papers  into  one  work  would  be 
disagreeable  to  you,  and  if  you  give  your  consent ;  secondly,  if  you  would 
send  a  complete  list  of  your  papers,  that  we  may  not  risk  omitting  any ;  and 
thirdly,  that  if  you  have  any  additions  or  corrections  to  make  to  any  of  them, 
he  may  add  them  in  your  name ;  and  fourthly,  if  you  will  allow  him  to 
correspond  with  you  during  his  labours,  in  case  he  should  require  any  explana- 
tions. He  will  wait  your  answer  to  begin  his  work.  For  my  own  part,  I  shall 
be  charmed  to  see  combined  together  papers  of  such  great  interest,  and  which 
at  present  are  scattered  among  works  so  voluminous,  that  one  has  them  not 
always  at  hand.  Receive,  dear  sir  and  colleague,  the  expression  of  the  high 
and  sincere  consideration  with  which  I  am  your  humble  and  devoted  servant, 

"  DE  CANDOLLE." 


THOMAS  ANDREW  KNIGHT,  ESQ.  51 

"  Sept.  2,  1830. 
"  MY  DEAREST  F , 

"  I  read  your  very  kind  letter  with  some  degree  of  melan- 
choly pleasure,  though  mingled  with  much  pain.  The  cer- 
tainty that  the  dear  object  for  whom  we  all  mourn  must  be 
happy,  must  be  to  you,  as  it  is  to  us  all,  the  chief  solace  and 
comfort.  She  is  much  happier  than  she  could  ever  have  been 
in  this  troubled  world ;  she  loses  nothing ;  for  a  few  short 
years  probably  of  more  painful  than  pleasing  existence  must 
have  brought  her  to  the  end  of  this  present  life. 

"  The  opinion  that  persons  quitting  this  life  have  felt  the 
glowing  happiness  you  describe,  is  not  new.  The  following 
lines  are  quoted  in  the  Spectator,  but  by  whom  written  I  do 
not  know : 

'  Leaving  the  old,  both  worlds  they  view, 
"Who  stand  upon  the  confines  of  the  new.' 

"  I  wish  to  repeat  to  you  again,  what  I  said  in  my  last,  that 
time  will  render  your  feelings  less  acutely  painful  than  you 
can  now  imagine,  and  that  we  may  look  back  upon  such  scenes 
of  past  distress  with  some  degree  of  melancholy  pleasure,  parti- 
cularly when  we  can  look  forward,  as  you  can  with  confidence, 
to  meeting  the  dear  object  of  your  past  solicitude  in  a  better 
world.  I  need  not  tell  you,  if  words  would  tell,  what  I  feel  for 
your  sufferings,  but  you  have  still  some  blessings  left,  to  which 
a  large  portion  of  the  human  race  are  strangers,  and  I  hope 
you  will  look  forward  with  hope  to  the  remaining  portion  of 
your  life,  and  to  our  all  meeting  again  in  a  happier  world. 
Remember  me  most  kindly  to  Mr.  S. 

"  Your  ever  affectionate  Father." 

"  Doicnton,  May  30, 1833. 

"MY  DEAREST  CHARLEY, 

''  It  was  with  very  painful  feelings  that  I  interfered  to  per- 
suade you  not  to  go  to  Paris,  upon  which  {  thought  you  had 
set  your  heart :  and  I  felt  great  pain  at  the  thoughts  of  robbing 

E  2 


52  LIFE    OF 

you  of  pleasure ;  but  I  thought  I  foresaw  danger,  much  danger, 
in  your  going,  in  the  state  of  health  I  thought  you  in ;  and  I 
should  have  been  most  miserable  had  you  gone.  It  is  a 
generally-received  opinion  that  age  blunts  the  feelings ;  but  I 
could  never  at  any  period  of  my  life  have  felt  more  acutely 
than  I  now  feel  everything  in  which  your  health  and  com- 
forts are  involved.  My  own  life  I  value  at  little ;  I  have  only 
to  look  forward  to  increasing  debility  and  decay  of  power  of 
body  and  mind :  but  to  your  health  and  life  I  look  forward 
with  very  different  feelings,  and  I  am  much  more  anxious  to 
see  you  in  health  than  to  retain  my  own  life. 

"  You  must  spend  the  enclosed  cheque,  which  you  were  to 
have  spent  at  Paris,  in  any  way  that  may  give  you  most  plea- 
sure ;  and  I  insist  on  your  keeping  it.  I  shall  bear  the  expense 
of  a  journey  to  Paris,  whenever  you  choose  to  go. 

"  Thy  ever  affectionate  Father,  T.  A.  K." 

"  Downton,  July  19,  1834. 

"  DEAREST  E , 

"  I  have  sent  you  a  draft  on  my  banker,  which  I  hope  will 
enable  you  to  send  poor  Horace  to  the  Lee  without  incon- 
venience. You  have  both  had  a  severe  struggle,  but  I  trust 
your  constitution  has  not  been  permanently  injured,  and  I 
venture  to  hope  that  his  (as  not  unfrequently  occurs)  has  been 
favourably  changed  and  improved. 

"  The  termination  of  hot  dry  weather,  and  the  abundant 
rain  of  yesterday,  of  which  I  hope  and  conclude  you  have  had 
a  share,  will,  I  trust,  be  favourable  to  poor  Horace. — I  have 
been  in  some  degree  confined  by  one  of  my  little  attacks  of 
gout,  and  my  foot  continues  slightly  swelled,  but  I  have  never 
been  prevented  going  to  my  garden. 

"  Your  mother  is  pretty  well,  but  I  am  sorry  to  say  not  so 
strong  as  she  was  last  year.  She,  however,  walks  to  church 
and  back  without  suffering  from  too  much  fatigue ;  and  unless 
after  sleeping  ill,  her  health  is  tolerable,  and  her  appetite  not 
defective ;  and  although  she  is  not  so  strong  as  I  could  wish  to 


THOMAS    ANDREW    KNIGHT,    ESQ.  53 

see  her,  she  is  upon  the  whole  well  for  her  time  of  life.  I  beg 
to  be  kindly  remembered  to  Mr.  Walpole,  and  pray  tell  him  that 
I  shall  be  happy  to  see  him  here  for  as  long  a  period  as  will  suit 
his  engagements. 

"  Ever  your  affectionate  Father." 

Mr.  Knight  continued  occasionally  to  communicate  the 
results  of  his  observations  and  investigations  to  the  Royal  and 
Horticultural  Societies.  His  last  paper  in  the  Philosophical 
Transactions  was  "  On  the  hereditary  Instincts  of  Animals/' 
which  was  read  on  the  25th  of  May,  1837.  He  took  much 
pleasure  in  cultivating  the  attachment  of  the  brute  creation, 
and  it  was  sometimes  a  subject  of  doubt  whether  his  children's 
pet  birds  and  animals  shared  most  largely  in  their  affection  or 
in  his ;  but  besides  the  indulgence  of  the  kindness  of  his  dis- 
position, he  was  thus  afforded  opportunities  of  observing  many 
peculiarities  in  the  habits  of  creatures  thus  brought  imme- 
diately under  his  eye,  and  relieved  from  the  restraint  which 
the  fear  of  man,  by  long  continuance  converted  into  an  in- 
stinct, usually  throws  in  the  way  of  the  naturalist.  His  fond- 
ness for  animals  was  not  of  that  senseless  kind  which  is  shown 
by  lavishing  unreasonable  indulgences  on  them ;  but  it  was 
dictated  by  a  true  benevolence,  which  would  have  led  him  to 
suffer  pain  himself,  rather  than  have  been  the  cause  of  it  to  a 
worm  or  a  fly.  He  was  very  particular  as  to  the  manner  in 
which  the  game  and  poultry  were  killed  for  the  supply  of  his 
table;  and  he  sometimes  even  superintended  the  operation 
himself,  that  he  might  be  sure  it  was  done  in  the  manner 
calculated  to  cause  least  pain.  At  the  time  when  he  was  an 
eager  sportsman,  he  has  often  been  known  to  spend  half  the 
day,  and  remain  out  long  after  his  dinner-hour,  in  hunting  for 
a  wounded  bird ;  and  if  unsuccessful  in  his  search,  the  idea  of 
the  sufferings  of  the  poor  creature  seemed  to  weigh  upon  his 
mind,  and  he  would  not  unfrequently  resume  his  search  early 
on  the  following  morning. 

Among  domesticated  animals,  Mr.  Knight  particularly  cle- 


54  LIFE    OF 

lighted  to  trace  the  hereditary  direction  which  cultivation 
through  successive  generations  had  given  to  natural  instinct ; 
and  in  the  course  of  his  experiments  on  the  improvement  of 
fruit  and  animals,  he  had  made  many  curious  observations  as 
to  the  qualities  which  are  transmitted  by  one  or  the  other 
parent ;  and  he  sometimes  amused  himself  with  endeavouring 
to  trace  in  human  subjects  the  same  analogy,  by  which  certain 
moral  and  physical  peculiarities  were  derived,  some  from  one 
parent,  and  some  from  the  other,  and  which  he  was  disposed 
to  imagine  might  be  reduced  to  something  like  rule.  His 
opinions  on  this  subject  are  glanced  at  in  the  subjoined  letter 
to  Sir  George  Mackenzie,  as  well  as  his  view  on  the  tendency  of 
modern  education,  both  immediately  and  prospectively ;  and  a 
few  extracts  from  letters  to  other  of  his  friends  touching  on 
similar  points  will  follow. 

"  Downton,  Sept.  29,  1836. 

"My  DEAR  SIR, 

"  I  have  delayed  troubling  you  with  a  letter,  till  I  had  read 
with  attention  both  your  little  publications,  and  that  of  Dr. 
Caldwell.  Both  have  given  me  very  great  pleasure  ;  and  though 
I  cannot  say  that  I  am  so  much  a  phrenologist  as  either  of  you, 
yet  I  perfectly  agree  with  you  in  the  conclusion  which  you  have 
drawn  in  a  great  extent  of  cases,  that  certain  forms  of  skull 
are  favourable,  as  indicating  powers  of  thought ;  and  I  have  long 
believed  that  exertion  of  mind  through  successive  generations, 
and  proper  selection  of  males  and  females,  might  give  not  only 
greatly  enlarged  powers  of  mind,  but  also  better  organised 
brain,  and  skulls  of  better  forms.  Upon  the  ill  effects  of 
modern  education  we  are  entirely  of  the  same  opinion ;  and  I 
perfectly  agree  with  Dr.  Caldwell  respecting  the  ill  effects  of 
subjecting  the  brain  of  young  subjects  to  any  degree  of  painful 
labour.  I  have  seen,  during  the  course  of  a  very  long  life,  many 
very  clever  over-educated  children ;  but  I  have  never  seen  any 
instance  in  which  the  brain- worn  child  of  twelve  years  old  dis- 
played at  a  later  period  much  powers  of  mind.  Talents  which 


THOMAS    ANDREW    KNIGHT,    ESQ.  55 

have  been  early  visible,  have,  in  a  great  variety  of  instances, 
continued  to  improve ;  but  the  possessors  of  these  were  not 
early  subjected  to  more  labour  than  they  could  bear ;  and  the 
ordinary  labours  of  education  were  not  in  any  degree  oppres- 
sive to  them. 

"  I  also  believe  Dr.  Caldwell's  opinion,  that  dyspeptic  cases 
are  to  a  great  extent  brain  cases,  to  be  well  founded.  He  has 
not  mentioned  the  singular  discovery  of  Dr.  Wilson  Philip,  that 
if  the  eighth  pair  of  nerves  be  divided,  and  the  divided  ends  be 
made  to  point  in  somewhat  different  directions,  and  the  nervous 
communication  be  thus  intercepted,  digestion  is  immediately 
suspended  totally ;  but  that  it  may  be  made  to  go  on  perfectly 
well  by  causing  a  current  of  galvanic  fluid  to  pass  down  from 
the  neck  to  the  stomach.  Your  late  illustrious  countryman, 
and  my  fellow-collegian  and  friend,  Dr.  Baillie,  entertained  pre- 
viously, I  believe,  somewhat  similar  opinions  respecting  the 
influence  of  the  operation  of  the  brain  upon  the  stomach.  Soon 
after  my  opinions  respecting  the  creations  and  motions  of  the 
fluids  of  plants  and  other  matters  connected  with  vegetable 
physiology  were  made  public,  and  when,  with  the  exception  of 
Sir  Joseph  Banks,  I  had  no  supporter,  my  time  and  mind  were 
laboriously  occupied  in  a  great  variety  of  experiments,  I  became 
unwell,  my  stomach  ceased  to  act,  and  I  thought  myself  fast 
approaching  to  the  termination  of  my  labours.  I  then  con- 
sulted Dr.  Baillie,  who  gave  me  an  extraordinary  prescription  : 
— '  Take  no  more  medicine  ;  walk  more,  and  think  less.' 

"  I  entertain  very  nearly  as  exalted  an  opinion  of  the  ignorance 
of  a  large  portion  of  our  legislators  as  you  do  :  either  they  can- 
not, or  they  will  not  think.  The  Mayor  of  Worcester  some 
years  ago,  when  George  III.  addressed  him,  said,  '  Please  your 
majesty,  Lord  Coventry  speaks  for  me.'  Many  of  our  legis- 
lators might  say,  '  and  thinks  for  me.'  As  sagacity  in  the  brute 
creation  certainly  becomes  hereditary  when  exercised  through 
successive  generations,  stupidity,  I  believe,  becomes  hereditary 
also ;  and,  according  to  Dr.  Caldwell's  theory,  the  injurious 
effects  of  too  early  labour  of  the  infant  brain,  must  operate  here- 


56  LIFE    OF 

ditarily.     The  early  and   excessive  labour  to  which  girls  are 
subjected  in  acquiring  skill  in  music,  has  long  appeared  to  me 
to  operate  very  injuriously  upon  their  constitution  and  form. 
The  roses  in  young  ladies'  cheeks,  if  unchanged,  would,  I  do  not 
doubt,  appear  much  less  bright  to  my  eyes  now  than  they  did 
half  a  century  ago  :  indeed,  I  am  sure  that  it  is  so  ;  for  I  recol- 
lect perfectly  well,  that  when  I  was  a  child,  the  plumage  of  the 
breasts  of  the  male  chaffinches  appeared  to  me  nearly  as  bright 
as  those  of  the  male  bullfinch  now  do  ;  but  I  can  distinguish 
straight  from  crooked  now,  as  well  as  I  could  do  at  any  period 
of  my  life ;  and  I  am   quite  certain  that  the  hollow7,   sunken 
chests  presented  by  many  of  the  young  ladies  of  the  present 
day  of  the  affluent  and  highly-cultivated  classes  were  not   as 
common,  or  nearly  so,  sixty  years  ago,  as  they  now  are  ;  and  I 
have  heard  on  good  authority,  that  such  flat  and  sunken  chests 
are  not  seen  among  the  less  educated  girls  of  Ireland.     With 
us  the  ears  and  fingers  of  girls  are  exercised,  not  their  minds 
rationally  exerted  and  amused ;  and  I  cannot  avoid  believing 
that  the  offspring  of  such  parents  are  often  born  without  the 
power  of  thinking  deeply.     I  have  heard  it  remarked  by  a  very 
sensible  countryman  of  yours,  that  among  families  which  have 
long  lived  in  affluence  and  been  highly  educated,  a  hundred 
men  of  quick  parts  would  be  found  for  one  deep  reasoner. 

"  I  beg  to  assure  you,  that  I  felt  very  highly  gratified  by  the 
belief  that  your  very  short  visit  to  Downton  proved  agreeable  to 
you  ;  and  Mrs.  Knight,  and  the  other  parts  of  my  family  who 
had  the  pleasure  to  meet  you  here,  have  begged  me  strongly  to 
express  their  hopes  and  wishes  that  you  will  soon  repeat  it,  and 
for  a  longer  period.  I  cannot  but  feel  highly  flattered  and  gra- 
tified by  the  published  account  you  were  so  kind  as  to  send  me 
of  your  visit  to  me,  but  I  fear  that  your  friendship  has  led  you 
to  speak  much  more  favourably  of  me  than  I  deserve. 

"  I  am  much  inclined  to  doubt  whether  any  phrenologist,  by 
examining  the  exterior  form  of  our  heads,  would  be  able  to  de- 
cide that  our  minds  resembled  each  other,  as  I  think  they  do, 
and  as  my  family  all  thought.  I  have  heard  several  people 


THOMAS    ANDREW    KNIGHT,    ESQ.  57 

remark  that  my  head  and  Davies  Gilbert's  are  alike,  and  my 
family  made  the  same  observation.  Mathematics  have  been  the 
favourite  study  of  my  ancestors,  so  that  nature  perhaps  made 
me  for  a  mathematician,  and  accident  a  naturalist. 

"  I  shall  have  great  pleasure  in  sending  you  anything  which 
my  garden  affords,  and  you  wish  to  receive,  either  in  the  autumn 
or  in  spring,  as  you  will  direct,  with  models  of  my  traps.  Mrs. 
Knight  and  my  family  beg  to  join  in  kind  remembrances,  and 
I  remain,  my  dear  Sir,  very  sincerely  yours, 

"  T.  A.  K." 

The  subjoined  is  an  extract  from  the  account  alluded  to  of 
a  visit  to  the  President  of  the  Horticultural  Society  of  London, 
from  the  pen  of  Sir  George  Stewart  Mackenzie,  Bart.,  which 
appeared  in  the  Edinburgh  Chronicle  of  September  1838, 
describing  the  impression  made  on  his  mind  by  a  day  spent  with 
Mr.  Knight,  at  Downton. 

"  The  venerable  and  talented  proprietor  of  Downton,  sur- 
rounded by  a  princely  domain  of  ten  thousand  acres  of  rich 
and  beautiful  country,  thinks  of  nothing  but  of  what  may  be 
useful  to  his  fellow-creatures.  He  received  us  with  that  un- 
ostentatious but  kindly  welcome  which  displayed  the  true 
spirit  of  hospitality  ;  regarding  a  visit  as  a  favour  conferred  on 
the  host,  and  not  on  the  guest ;  and  which  at  once  excites 
mutual  benevolence,  that  operates  like  magic  in  giving  birth  to 
friendship.  It  is  true,  we  had  seen  our  excellent  host  once 
before,  and  enjoyed  occasional  correspondence  with  him  during 
many  years.  But  notwithstanding,  on  entering  a  house  for  the 
first  time,  we  felt  a  little  awkward,  as  Scotchmen  generally  do 
in  such  circumstances.  In  a  short  time,  however,  this  was 
brushed  off  by  attention  from  every  side  ;  and  we  experienced 
with  much  delight  the  ease,  grace,  and  kindliness  of  English 
hospitality. 

"  Our  venerable  host,  active  and  energetic  in  his  78th  year  as 
a  man  of  40,  is  one  of  those  rarities  among  men,  that  know 


58  LIFE    OF 

everything — who  can  put  their  hand  to  everything,  and  give 
a  sound  philosophical  reason  for  what  they  do.  He  is  one  who 
can  discern  rottenness  in  church  and  state,  as  well  as  canker 
in  a  fruit-tree,  and  can  fathom  both.  He  can  see  the  traps 
set  for  the  people,  as  they  are  closely  analogous  to  those  in- 
genious ones  he  sets  for  the  blackbirds  that  come  to  devour  his 
fruit.  He  soon  introduced  us  to  his  garden,  which  we  were 
most  anxious  to  see.  We  found  no  display — nothing  for  show 
— all  was  perfectly  simple  and  business-like,  and  full  of  experi- 
ment. Various  modes  of  culture  were  in  progress  with  every- 
thing ;  and  reasons  were  given  for  commencing  every  experi- 
ment. 

"  Were  we  to  attempt  describing  all  that  we  noticed  in  a 
garden  at  which,  on  account  of  its  plainness,  those  who  regard 
show  and  display  would  turn  up  their  noses,  it  would  be  pro- 
per to  think  of  writing  a  volume.  We  will  therefore  conclude 
by  stating  that  Mr.  Knight  has  not  yet  subscribed  to  the  theory 
of  the  rotation  of  crops  derived  from  the  experiments  which 
showed  that  plants  deposited  excrementitious  matter;  the 
theory  being  that,  while  such  matter  is  useless  to  the  plants 
that  reject  it.  other  plants  are  nourished  by  it.  Further  ex- 
periments are  wanted  to  elucidate  this  curious  subject ;  and  no 
one  has  better  means  to  confirm  or  overset  the  theory  than 
Mr.  Knight." 

The  simple  means  by  which  Mr.  Knight  effected  his  earliest 
and  most  important  discoveries  have  been  already  mentioned ; 
and  Sir  George  M'Kenzie  correctly  describes  the  appearance 
of  the  garden  at  Downton,  at  a  period  when  Mr.  Knight  had 
for  many  years  possessed  the  power  of  obtaining  whatever 
would  have  facilitated  the  most  extensive  application  of  his  own 
theories  to  practice ;  but  it  was  still  characterised  by  the  same 
simplicity.  In  his  own  mind  were  combined,  probably  more 
than  in  that  of  any  other  person  who  ever  lived,  the  qualities 
of  a  physiologist  and  a  practical  gardener ;  and  whatever  suc- 
cess attended  his  horticultural  operations  resulted  from  his 


THOMAS    ANDREW    KNIGHT,    ESQ.  59 

sound  knowledge  of  the  vital  actions  of  plants,  founded  on  phi- 
losophical investigation,  and  his  skilful  adaptation  of  the  ex- 
ternal forces  by  which  they  are  regulated. 

The  following  extracts  from  various  letters  of  Mr.  Knight's 
will  serve  further  to  illustrate  his  views  on  various  questions 
connected  with  the  habits  of  domesticated  animals. 

"  The  observations  of  your  sporting  friend,  that  dogs  which 
have  not  been  regularly  and  well  fed  will  bury  their  superfluous 
food,  is  well  founded ;  but  perhaps  it  had  been  more  correctly 
applied,  if  he  had  extended  it  to  families  of  dogs  ;  for  I  do  not 
think  that  the  descendant  of  a  long  succession  of  parlour  and 
lap  dogs  would  do  this,  though  he  were  not  well  fed  ;  and  I 
entertain  very  little  doubt  that  the  offspring  of  a  breed  which 
through  successive  generations  had  been  ill  fed,  would  hide  his 
superfluous  food,  though  he  had  been  well  and  regularly  fed. 

"  I  have  been  struck  with  astonishment  to  see  to  what  an 
extent  the  offspring  of  a  breed  of  Norfolk  water-dogs,  which 
they  there  call  Retriever,  would  do  spontaneously,  what  their 
parents  had  been  taught  to  do,  of  which  I  could  give  many 
instances. 

"  If  you  contrast  the  various  actions  of  the  different  families  of 
dogs, — the  truffle-hunter — the  fox-hunter — the  pointer — setter 
—  springing-spaniel  —  shepherd's  dog  —  bull-dog  —  the  silent 
South-sea  dog,  with  the  native  manners  of  the  wild  type,  the 
wolf,  we  shall  not  wonder  at  many  irregularities  in  the  actions 
of  different  families  of  domesticated  animals  of  the  same 
species." 

"  I  think  if  the  habits  of  any  two  families  of  the  same  species 
of  domesticated  animals  were  attentively  watched  and  compared, 
great  diversities  of  action  would  be  observable.  If  we  were  to 
draw  our  conclusions  respecting  the  sagacity  of  the  horse  from 
observations  of  the  actions  of  a  Welsh  mountaineer  pony,  we 
should  pronounce  that  species  of  animal  to  be  singularly  saga- 
cious in  distinguishing  a  bog  from  sound  ground.  He  knows 


60  LIFE    OF 

it  perfectly  by  the  smell ;    but  the  blood-horse  shows  no  such 
sagacity — he  is  a  perfect  idiot  in  that  respect. 

"  If  a  botanist  who  had  only  seen  that  variety  of  the  Brassica 
oleracea  which  we  call  a  cauliflower,  described  it,  how  little 
would  his  account  agree  with  the  observations  others  would 
have  made  who  had  seen  the  Scotch  kale  and  ox-cabbage  !  Bees 
have  been  stated  to  fortify  their  hives  against  the  ingress  of 
enemies  in  those  countries  where  such  enemies  are  found  ;  while 
we  see  no  indication  of  such  precautions  here,  where,  through 
many  successive  generations,  no  such  enemies  have  presented 
themselves." 

"  We  find  abundant  facts  to  prove  that  not  only  animals,  but 
plants  also,  adapt  their  habits  to  incidental  external  circum- 
stances. The  crab,  the  pear,  and  the  plum  are  produced  in  a 
state  of  nature  only  upon  trees  covered  with  sharp  thorns ;  and 
wheat,  in  anything  approaching  its  natural  state,  is  always 
strongly  bearded. 

"  The  wild  duck  sagaciously  conceals  its  nest,  and  covers  its 
eggs  when  it  leaves  them  ;  but  the  same  bird  domesticated  often 
drops  them  at  random  ;  and  if  it  makes  a  nest,  it  is  in  so  open 
a  place,  that  the  crows  destroy  them.  The  tame  goose 
cannot  be  trusted  with  its  own  eggs  ;  for  it  will  sit  so  long,  when 
it  lays  one,  that  it  will  spoil  those  previously  laid." 

An  anecdote  is  given  in  the  first  volume  of  Mr.  Jesse's  Glean- 
ings in  Natural  History,  on  the  authority  of  Mr.  Knight,  of  a 
fly-catcher,  which  he  used  often  to  mention  as  one  of  many 
instances  that  had  come  under  his  observation,  of  the  exercise 
of  a  degree  of  intelligence,  apparently  surpassing  the  limits  of 
the  instinct  given  to  animals  to  guide  and  direct  their  proceed- 
ings in  the  ordinary  mode  of  existence  appointed  to  them,  and 
to  indicate  a  power  of  adapting  the  habits  of  an  individual,  on 
whom  cultivation  had  not  exerted  any  influence,  to  exigencies 
which  could  rarely,  if  ever,  occur. 

This  bird,  for  several  successive  years,  built  its  nest  in  a  stove 


THOMAS    ANDREW    KNIGHT,    ESQ.  61 

in  the  kitchen  garden  at  Downton  Castle,  into  which  it  had  free 
access  through  an  aperture  made  to  admit  air.  Mr.  Knight 
observed  that  during  the  process  of  incubation  the  old  bird  was 
absent  much  more  often  from  its  nest  than  is  usual  during  that 
process,  and  yet  that  it  had  evidently  not  abandoned  its  eggs  ; 
he  therefore  watched  its  motions  closely,  and  soon  discovered 
the  curious  fact,  that  the  bird  quitted  its  nest  when  the  thermo- 
meter rose  to  about  /1°  or  72°,  and  returned  to  it  when  the 
temperature  sunk  again ;  thus  seeming  to  have  a  knowledge 
that  only  a  certain  degree  of  heat  was  necessary  to  the  eggs, 
and  that,  being  furnished  from  another  source,  its  own  labours 
might  be  dispensed  with.  The  ostrich  in  the  torrid  regions  of 
Africa  leaves  her  eggs,  in  like  manner,  to  the  influence  of  the 
sun's  rays  during  the  day ;  but  Buffon  and  other  naturalists 
deny  that  there  is  any  foundation  for  the  vulgar  belief  of  her 
abandoning  them  altogether,  and  state  that  she  constantly 
returns  to  sit  upon  them  during  the  night." 

The  two  following  were  addressed  to  Dr.  Be  van,  author  of  a 
work  on  the  honey-bee  : — 

"  In  the  course  of  my  experiments  I  have  had  many  oppor- 
tunities of  observing  the  peaceful  and  patient  disposition  of 
bees,  as  individuals,  which  Mr.  John  Hunter  has  also  in  some 
measure  noticed.  When  one  bee  had  collected  its  load  and 
was  just  prepared  to  take  flight,  another  often  came  behind  it, 
and  despoiled  it  of  all  it  had  collected.  A  second,  and  even  a 
third  load  was  collected,  and  lost  in  the  same  manner,  and  still 
the  patient  insect  pursued  its  labour  without  betraying  any 
symptom  of  impatience  or  resentment*  :  when,  however,  the 
hive  is  approached,  the  bee  appears  often  to  be  the  most  irritable 
of  animals.  They  are  probably  by  nature  little  disposed  to  fight, 

*  The  author  of  Insect  Architecture  in  the  Library  of  Entertaining  Know- 
ledge, after  quoting  the  above  from  Mr.  Knight,  adds, — "  Probably  the  latter 
circumstance  at  which  Mr.  Knight  seems  to  have  been  surprised,  was  nothing 
more  than  an  instance  of  the  division  of  labour,  so  strikingly  exemplified  in 
every  part  of  the  economy  of  bees." 


62  LIFE    OF 

when  they  have  nothing  to  fight  for,  as  when  they  have  first 
swarmed ;  but  they  appear  to  become  acquainted,  and  to  place 
confidence  in  persons  who  are  much  with  them,  and  from  whom 
they  have  never  received  injury.  A  labourer  who  looked  after 
my  bees  at  the  time  I  was  making  experiments  upon  them, 
would  put  his  fingers  into  the  mouth  of  the  hive,  and  push 
away  the  bees  to  show  me  the  newly-formed  comb,  without 
apparently  giving  any  offence." 

"  Downton,  July  1829. 

"  I  believe  that  I  have  been  to  an  unjust  extent  sceptical 
respecting  the  accuracy  of  M.  Hubert's  statements.  I  have 
found  so  much  inaccuracy  in  the  writings  of  vegetable  physiolo- 
gists, that  I  am  often  probably  somewhat  unreasonably  difficult 
to  convince  ;  and  I  recollect  one  of  my  friends  having  told  me 
that  when  he  had  said  to  Sir  Joseph  Banks  that  I  believed  some 
statement,  Sir  Joseph  jestingly  remarked,  'he  (meaning  me)  is 
an  excellent  person  to  believe  after.'  The  evidence  of  bee's-wax 
being  an  animal  secretion  is  so  strong,  that  I  cannot  question 
it,  and  I  think  you  have  satisfactorily  explained  why  it  may  be 
made  into  thinner  combs  in  the  autumn  than  in  the  spring*.  I 
think  you  will  also  find  it  more  brittle  and  white  than  the  spring 
combs  are  ;  though  possibly  the  spring  combs  may  have  received 
some  colouring  matter  after  their  first  formation.  Whatever 
may  be  the  cause  of  the  difference  of  colour,  I  believe  you  will 
find  such  difference  to  exist ;  and  a  Polish  friend  of  mine, 
whose  acquaintance  with  the  management  of  bees  in  that 
country,  where  the  wax  forms  an  article  of  considerable  value 
comparatively  with  the  price  of  other  articles,  was  extensive  and 
accurate,  informed  me  that  the  autumnal  combs  are  always 

*  Dr.  Bevan  had,  in  answer  to  some  arguments  of  Mr.  Knight's  in  favour  of 
wax  being  a  vegetable  production,  detailed  experiments  to  prove  that  it  was 
secreted  by  the  membrane  which  lines  the  sacklets  of  the  working  bee  ;  and  he 
accounted  for  the  more  liberal  use  of  it  in  spring  by  the  supposition  that  the 
comb  was  made  thicker  in  that  season  for  the  purpose  of  resisting  the  struggles 
of  the  nymphs,  and  that  its  tenuity  in  autumn  might  be  attributable  to  the  cells 
being  at  this  season  chiefly  intended  for  repositories  for  honey. 


THOMAS    ANDREW    KNIGHT,    ESQ.  63 

separated  from  the  others  on  account  of  their  superior  white- 
ness, and  the  consequent  diminished  labour  of  bleaching*. 

"  I  have  been  and  am  still  engaged  in  some  experiments  upon 
the  potato,  which  plant  has  given  me  more  physiological  infor- 
mation than  all  the  remainder  of  the  vegetable  world ;  and 
where  it  has  not  given  me  the  information  I  wanted,  it  has 
directed  me  where  to  find  it.  I  think  it  is  capable  of  much 
improvement  as  an  article  of  human  food,  and  that  varieties 
may  be  formed  which  as  food  to  animals  will  cause  a  larger 
supply  of  animal  food  to  be  brought  to  the  market  than  can  be 
obtained  from  all  the  varieties  of  the  turnip. 

"  If  business  or  pursuit  of  pleasure  should  bring  you  into 
this  vicinity,  I  shall  be  happy  to  see  you  at  Downton.  I  have 
not  much  to  show  that  is  likely  to  interest  you,  and  my  habits 
of  activity  are  necessarily  sinking  under  the  weight  of  seventy 
years  ;  though  I  am  grateful  that  I  still  retain  my  health,  and 
my  powers  of  memory  and  of  mind  little  changed,  I  believe. 

"  I  remain,"  &c. 

"I  wrote  down,  some  days  ago,  a  few  observations  upon  the 
screech-owl,  which  was  formerly  supposed  often  to  visit  the  win- 
dows of  the  chambers  of  the  sick  and  dying.  Lady  Macbeth  says, 
( It  was  the  owl  that  shrieked,  the  fatal  bellman,  which  gives  the 
stern'st  good-night.'  I  happened  once  to  have  heard  this  shriek, 
which  was  uncommonly  loud,  and  most  hideous,  bearing  no 
resemblance  whatever  to  any  of  the  ordinary  cries  of  the  owl.  I 
saw  the  bird  at  the  moment  when  it  was  uttering  its  horrid  shriek 
at  the  window  of  a  person  who  was  lying  ill  of  a  fever.  The 
owl  was  at  that  time  a  greatly  more  abundant  bird  than  it  now 
is ;  and  it  was,  I  do  not  doubt,  led  by  its  nice  sense  of  smell, 
and,  like  the  raven,  was  the  announcer  of  present,  not  the 
prophet  of  future  ill,  the  patient  having  in  this  case  recovered." 

"  Having  retired  under  the  shade  of  an  oak  in  a  very  hot 

*  Mr.  Knight  has  suspected  this  to  have  been  caused  by  the  bleaching  effect 
of  the  atmosphere  during  the  snimner. 


64  LIFE   OF 

morning  of  September  1st,  1835, 1  observed  a  shower  of  honey- 
dew  to  descend  in  innumerable  small  globules  (which  become 
visible  when  seen  in  one  light)  from  the  leaves  of  the  tree, 
upon  which  I  found  a  very  large  number  of  aphides,  from  whose 
bodies  the  honey-dew  appeared  to  be  ejected  with  considerable 
force.  I,  in  consequence,  brought  home  a  branch  of  the  tree, 
which  I  so  placed,  that  the  light,  in  an  otherwise  dark  room, 
should  shine  only  upon  such  branches ;  and  I  then  obtained 
clear  evidence  that  the  aphis  can  discharge  its  honey  with  con- 
siderable force.  It  is  consequently  often  found  in  situations  at 
which  it  could  not  have  arrived  by  the  mere  influence  of  gravi- 
tation. I  suspect  this  circumstance  has  led  to  the  belief  of  the 
existence  of  two  kinds  of  honey-dew,  one  being  immediately 
ejected  by  plants  ;  I  doubt  the  existence  of  more  than  one 
kind,  for  I  have  often  found  a  minute  aphis,  by  the  aid  of  a  lens, 
in  the  small  globules,  apparently  emitted  by  a  leaf." 

These  specimens  may  serve  to  show  in  some  degree  how 
Mr.  Knight's  mind  was  always  at  work,  and  with  what  alacrity 
it  seized  on  whatever  contributions  of  knowledge  nature  threw 
in  his  way,  and  also  the  manner  in  which  he  extracted  out  of 
every-day  experience  facts  which  illustrated  or  confirmed 
former  speculations. 

He  carried  on  a  very  extensive  correspondence,  not  only  with 
many  of  the  men  most  distinguished  for  their  attainments  in 
science  in  Great  Britain,  but  with  most  of  the  writers  on  vege- 
table physiology  and  horticulture  on  the  continents  of  Europe 
and  America.  A  large  collection  of  interesting  letters  were 
preserved  by  him ;  but  the  limits  of  this  memoir  precludes  the 
insertion  of  more  than  the  few  that  have  been  given.  He  was 
also  a  corresponding  member  of  numerous  Societies  for  the  en- 
couragement of  horticulture  and  agriculture  in  Europe,  Ame- 
rica, and  Australia. 

The  readiness  with  which  he  communicated  the  results  of  his 
investigations,  and  the  practical  objects  to  which  they  led, 
caused  incessant  application  to  be  made  to  him  by  horticul- 


THOMAS    ANDREW    KNIGHT,    ESQ.  65 

turists  of  all  grades ;  and,  as  he  never  withheld  information  or 
assistance  from  the  most  humble  of  his  applicants,  his  time  was 
much  occupied  in  answering  letters,  and  in  sending  off  packages 
of  plants,  &c.  of  the  new  varieties  of  fruits  and  vegetables  he 
had  raised,  which  he  distributed  with  an  unsparing  hand  ;  still 
from  the  time  the  new  poor  laws  came  into  operation,  notwith- 
standing his  advanced  age  and  his  numerous  avocations,  he 
took  an  active  part  in  their  administration ;  and  no  cause  but 
indisposition  ever  prevented  his  attending  the  weekly  meetings 
of  the  board  of  guardians  at  Ludlow ;  for  he  considered  that 
the  benefits  to  be  derived  from  this  law  would  be  materially 
diminished,  if  not  annihilated,  unless  the  country  gentlemen 
lent  their  assistance  in  enforcing  the  proper  fulfilment  of  its 
provisions. 

Another  subject  in  which  he  latterly  took  much  interest  was 
the  commutation  of  tithes ;  and  in  1834  he  published  a 
pamphlet,  suggesting  the  adoption  of  meat  as  the  basis  on 
which  to  found  the  calculations  of  the  value  of  tithes,  instead  of 
corn. 

Though  early  in  life  Mr.  Knight  had  been  considered  deli- 
cate, he  had,  for  a  long  course  of  years,  enjoyed  almost  unin- 
terrupted good  health,  which  his  mode  of  life  was  well  calculated 
to  confirm :  he  spent  many  hours  of  every  day  in  the  open  air, 
in  his  garden,  or  in  walking  about  his  estate :  he  had  always 
been  remarkable  for  his  abstemious  habits  ;  he  rarely  tasted 
wine  or  any  fermented  liquor,  and  ate  little  animal  food  ;  which 
it  is  to  be  feared  he  persevered  in  to  an  injurious  extent,  for, 
when  the  powers  of  the  stomach  became  diminished  by  the 
decay  incidental  to  old  age,  a  more  generous  diet  would  pro- 
bably have  had  a  beneficial  effect  on  his  constitution.  For  the 
last  three  years  of  his  life,  occasional  symptoms  of  dyspepsia 
appeared,  and,  during  the  winter  of  1 837-8,  he  suffered  a  good 
deal  from  derangement  of  the  digestive  organs,  which  at  times 
produced  a  very  distressing  sense  of  suffocation.  He  had  a 


66  LIFE    OF 

severe  attack  of  this  kind  in  April,  but  as  he  was  anxious  to 
have  the  advice  of  Dr.  Wilson  Philip,  he  proceeded  to  London 
at  the  usual  time. 

He  spent  a  day  with  his  friend  Mr.  Williams  on  the  road,  and 
though  much  enfeebled  by  his  illness,  he  bore  the  journey  with- 
out apparent  fatigue,  and  expressed  his  hopes  that  he  should 
soon  be  restored  to  his  usual  state  of  health.  On  the  1st  of 
May,  he  did  not  feel  equal  to  taking  the  chair  at  the  anniver- 
sary meeting  of  the  Horticultural  Society,  nor  did  he  ever  leave 
the  house  after  his  arrival  in  London ;  but  he  saw  several  of 
his  friends,  conversed  cheerfully,  and  seemed  to  enjoy  their 
society. 

The  medicines  prescribed  by  Dr.  Philip  had  relieved  several 
of  the  most  unfavourable  symptoms  ;  and  the  state  of  his  pulse, 
which  was  as  regular  as  that  of  a  person  in  perfect  health,  for 
some  time  led  his  family  to  hope  that  he  was  going  on  well, 
notwithstanding  that  his  amendment  was  less  decided  than 
they  wished ;  and  even  when  some  degree  of  anxiety  had  begun 
to  be  felt  as  to  the  final  issue  of  his  illness,  no  symptom  indi- 
cated immediate  danger ;  though  it  was  apparent,  from  the 
subjects  on  which  he  conversed,  that  he  thought  it  probable  he 
should  not  recover,  and  that  tenderness  for  the  feelings  of 
Mrs.  Knight  and  his  eldest  daughter,  who  were  with  him,  alone 
prevented  his  declaring  this  opinion  in  more  direct  terms. 

He  spoke  with  affection  of  the  absent  members  *  of  his 
family,  and  of  the  arrangement  he  had  made  of  his  affairs ; 
while,  to  those  who  had  the  happiness  of  being  present,  he 
expressed  in  most  affecting  terms  all  that  was  most  grateful  and 
consoling  to  them  to  dwell  upon,  of  his  feelings  to  them,  and 
of  his  deep  thankfulness  for  the  many  blessings  he  had  en- 
joyed in  the  course  of  his  long  life,  and  of  his  readiness  to 
leave  the  world  whenever  he  was  summoned  to  do  so. 

*  Sir  William  and  Lady  Rouse  Bougliton  were  detained  in  the  country  by 
the  serious  illness  of  the  former,  and  Mr.  and  Mrs.  Francis  Walpole  were 
abroad. 


THOMAS    ANDREW    KNIGHT,    ESQ.  6/ 

Illness  and  suffering  never  elicited  from  him  one  expression  of 
impatience ;  they  only  drew  forth  fresh  proofs  of  the  kindness 
and  unselfishness  of  his  nature.  At  times  the  sense  of  suffo- 
cation he  experienced  was  exceedingly  distressing,  but  the 
moment  that  a  diminution  of  the  symptoms  allowed  him  to 
speak,  he  never  failed  to  tell  those  about  him  that  he  was 
better,  knowing  the  comfort  it  would  afford  them. 

After  passing  a  tolerably  tranquil  night,  early  on  the  morning 
of  Friday,  May  llth,  1838,  he  suddenly  fell  back  on  his  pillow, 
and  drew  his  last  breath  without  a  sigh  or  a  struggle, 

His  end  was  as  peaceful  as  had  been  the  pursuits  and  occu- 
pations of  his  long  and  useful  life;  and  few  men  have  descended 
to  the  grave  more  beloved,  or  more  sincerely  regretted  by  all 
ranks  of  society. 

His  remains  were  interred  at  Wormesley  on  Tuesday,  May 
22nd,  near  to  those  of  his  brother  and  his  lamented  son. 

Many  of  Mr.  Knight's  friends  were  desirous  to  have  shown 
the  last  proof  of  regard  for  his  memory  by  attending  his  remains 
to  the  grave ;  but  such  offers  were  declined,  with  a  very  few 
exceptions,  from  a  conviction  that  a  simple  unostentatious 
funeral  would  best  have  accorded  with  his  own  feelings  when 
living.  Every  mark  of  respect  was  shown  in  the  towns  and 
villages  through  which  the  procession  passed ;  and  the  large 
body  of  his  tenantry,  of  whom  it  was  chiefly  composed,  as  they 
followed  him  to  his  last  resting-place,  evinced  how  strongly 
they  felt,  that  in  him  they  had  lost  their  best  friend,  and  the 
kindest  and  most  indulgent  of  landlords. 

A  monument  has  since  been  erected  to  his  memory  by  his 
widow,  with  the  following  inscription  from  the  pen  of  the 
Rev.  —  Lee. 


68  LIFE    OF 

THOMAE  .  ANDREAE  .  KNIGHT  .  A.M.  R.S.S. 
HORTULANORUM  .  SOCIETATIS  .  APUD  .  LONDINENSES  .  PRAESIDI 

QUEM  .  SUMMO  .  INGENII  .  ACUMINE  .  ET  .  VI  .  PRAEDITUM 

CERTAM  .  PERFECTAM  .  QUE  .  RERUM  .  SCIENTIAM  .  IMPENSE  .  PERQUIRENTEM 
IMPRIMIS.HORTORUM  .  CULTURAE .  PROVEHENDAE.  OPERAM  .  ET .  STUDIUM  .  NAVANTEM 

PIETAS  .  ERGA  .  DEUM 
QUEM  .  EX  .  TOTIUS  .  NATURAE  .  MENTE  .  ATQUE  .  ANIMO  .  BENEVOLUM  .  AGNOVIT 

COMITAS  .  ERGA  .  SUOS 
QUORUM  .  COMMODIS  .  STUDIO  .  ACERRIMO  .  INSERVIEBAT 

PARITER  .  EXORNAVERUNT 

RERUM  .  NATURAE  .  COGNITORI  .  DILIGENTISSIMO  .  ET  .  LOCUPLETI 

SCIENTIAE  .  ATQUE  .  DOCTRINAE  .  FAUTORI  .  STRENUO  .  ET  .  BENEFICO 

VIRO  .  OPTIMO  .  HOMINI  .  AEQUISSIMO 

CONJUX  .  CONJUGI  .   AMANTISSIMO 

H.   M.  P.   C.  L.   M. 
ANNO  .  SACRO  .  MDCCCXXXVIII. 

At  a  meeting  of  the  Horticultural  Society,  held  on  the  19th 
of  June,  for  the  purpose  of  electing  a  President  in  the  room  of 
Mr.  Knight,  it  was  resolved — "  That  this  meeting  deeply  deplore 
the  loss  the  Society  has  sustained  by  the  death  of  their  late 
President,  T.  A.  Knight,  Esq.,  an  individual  not  less  distin- 
guished for  his  private  worth  than  for  his  public  usefulness ; 
whose  memory,  from  the  urbanity  of  his  manners,  the  kindness 
of  his  disposition,  his  attachment  to  science  generally,  more 
especially  to  that  branch  patronised  by  this  Society,  will  be 
long  cherished,  as  his  decease  will  be  sincerely  lamented." 

In  December  following,,  the  Duke  of  Sussex  resigned  the 
Chair  of  the  Royal  Society,  and  in  a  farewell  address,  delivered 
on  this  occasion,  his  Royal  Highness  alluded  to  those  distin- 
guished members  whose  loss  the  Society  had  sustained  since  the 
last  anniversary  meeting,  and  when  speaking  of  Mr.  Andrew 
Knight,  described  him  as  "  having  possessed  very  great  activity 
of  body  and  mind,  with  singular  perseverance  and  energy  in  the 
pursuit  of  his  favourite  science ;  a  lucid  and  agreeable  writer* 
who  had  by  his  labours  developed  views  of  the  greatest  value 
and  interest  in  vegetable  physiology,  as  well  as  in  practical 


THOMAS  ANDREW  KNIGHT,  ESQ.  69 

horticulture."  After  giving  a  sketch  of  Mr.  Knight's  labours, 
his  Royal  Highness  concluded  by  saying,  "  It  would  be  difficult 
to  find  any  other  contemporary  author,  in  this  or  other  coun- 
tries, who  had  made  such  important  additions  to  the  knowledge 
of  horticulture  and  the  economy  of  vegetation." 

Before  closing  this  brief  and  imperfect,  though  it  is  hoped 
not  unfaithful  memoir  of  Mr.  Knight's  life,  a  portion  of  the 
task  which  is,  perhaps,  the  most  difficult  remains  to  be  accom- 
plished. 

If  those  by  whom  this  memoir  has  been  drawn  up  have  felt 
themselves  unequal  to  exhibit  the  workings  of  his  mind  in  the 
investigation  of  the  truths  of  philosophy ;  if  they  have  not  ven- 
tured to  point  out  what  are  the  errors  he  has  exposed,  and  the 
difficulties  he  has  cleared  up  ;  or  what  are  the  new  facts  that  he 
has  added  to  science,  it  is  satisfactory  to  them  to  reflect,  that 
his  own  works,  which  have  received  the  approbation  of  most  of 
the  naturalists  of  Europe,  have  done  this  more  fully  than  could 
have  been  effected  by  any  one  less  qualified  than  himself  to 
write  on  the  subject. 

But  the  acquisition  of  philosophic  truth,  and  the  study  of 
the  works  of  creation — which  we  have  the  highest  authority  for 
believing  to  be  not  merely  a  noble  and  legitimate  exercise  of 
man's  powers  of  mind,  but  one  acceptable  to  his  Creator,  and 
for  the  comprehension  and  investigation  of  which  his  mind 
seems  to  have  been  expressly  adapted — is  not  the  great  object 
of  life. 

It  is  in  the  cultivation  of  man's  moral  powers,  and  in  his 
reception  and  acting  upon  those  truths  which  the  highest 
exercise  of  reason  would  not  have  discovered,  that  the  end  of 
creation  is  to  be  looked  for :  and  the  memoir  of  Mr.  Knight 
would  be  incomplete,  without  an  attempt  at  least  to  delineate 
those  deeper  and  more  hidden  principles  which  stamp  the 
moral  and  religious  character  of  an  individual.  It  will  be  felt 
that  this  in  all  cases  is  a  delicate  and  difficult  task ;  and  if  any 
part  of  what  is  said  should  be  thought  to  have  been  dictated 
rather  by  affection  than  by  unbiassed  judgment,  it  will,  it  is 


70  LIFE    OF 

hoped,  be  conceded  that  Mr.  Knight's  own  family  had  far  more 
frequent  and  intimate  opportunities  of  knowing  his  feelings  and 
principles,  than  any  other  persons  could  possess;  and  in  finishing 
what  they  are  well  aware  is  a  feeble  delineation  of  his  character, 
by  touching  on  a  few  points  not  already  noticed,  they  trust  it 
will  be  believed  that  they  say  no  more  than  is  the  result  of  their 
sincere  convictions. 

Like  other  persons  of  ardent  temperament,  Mr.  Knight  felt 
strongly  on  all  occasions  ;  and  his  sense  of  honour  was  of  a 
nature,  perhaps,  almost  too  chivalrous  for  the  every-day  concerns 
of  life.  He  was  slow  to  discover  evil  in  others,  but  when  he 
had  been  once  led  to  suspect  a  want  of  integrity  and  fairness, 
he  too  hastily  expressed  such  opinion  ;  and  hence  he  sometimes 
might  have  appeared  to  those  who  did  not  know  the  working 
of  his  mind,  to  have  been  guided  by  feelings  very  opposite  to 
the  true  ones,  for  no  heart  ever  more  overflowed  with  kindness 
and  charity  to  all  mankind  than  his,  and  no  one  was  more 
sincerely  disposed  to  judge  of  others,  "  as  he  would  himself  be 
judged."  A  more  extended  intercourse  with  mankind  would 
probably  have  had  a  beneficial  influence  on  his  mind  on  this 
point,  but  it  would  perhaps  have  robbed  it  of  somewhat  of  that 
guilelessness  and  simplicity,  which  were  among  the  most 
engaging  peculiarities  of  his  character. 

In  politics,  the  same  apparent  bitterness,  but  originating  in 
the  same  high  feeling,  was  sometimes  displayed.  He  was  a 
Whig  of  the  old  school,  and  though  a  strong  advocate  for  refor- 
mation of  abuses,  and  an  admirer  of  liberal  measures,  he  was 
decidedly  opposed  to  more  extended  suffrage,  vote  by  ballot, 
triennial  parliaments,  and  other  schemes  of  the  ultra  Liberal 
party :  but,  from  having  lived  through  the  days  when,  owing  to 
the  long  continuance  of  one  party  in  power,  abuses  had  crept 
into  the  administration  of  government,  his  prejudices  had  been 
excited  against  the  Tories  ;  ^nd  truth  demands  the  admission, 
that  he  sometimes  expressed  himself  of  persons  and  measures 
in  terms  which  his  best  friends  regretted  ;  but  if  convinced  that 
he  had  formed  an  erroneous  judgment,  no  one  was  more  ready 


THOMAS    ANDREW    KNIGHT,    ESQ.  /I 

than  himself  to  admit  he  had  been  wrong  ;  and  his  forgiveness 
of  similar  offences  against  himself  and  his  forgetfulness  of 
injuries,  have  more  than  once  been  manifested  in  instances 
where  others  thought  the  provocation  received  might  have 
justified  a  lasting  estrangement. 

The  warmth  of  his  feelings,  it  cannot  be  denied,  sometimes 
warped  his  judgment ;  and  the  faculty  of  fairly  balancing  oppo- 
site contingencies,  and  giving  to  each  its  due  weight,  and  thus 
arriving  at  a  cool  and  impartial  estimate,  was  not  one  of  the 
qualities  in  which  his  understanding  most  excelled.  He  was 
too  much  disposed  to  act  on  the  impulse  of  the  moment,  and 
this  often  exposed  him  to  subsequent  inconvenience  and  an- 
noyance ;  though  the  ill  consequences  that  might  have  arisen 
from  this  failing  were  generally  averted  by  the  kindness  of  his 
heart,  and  the  strict  integrity  and  sense  of  justice  by  which  all 
his  actions  were  controlled. 

It  must  always  be  difficult  for  children  to  speak  of  the  fail- 
ings of  a  father ;  and  this  difficulty  is  tenfold  increased,  when 
these  were  so  overbalanced  by  what  is  great  and  good,  as  was 
the  case  in  Mr.  Knight's  character,  and  when  the  kindness 
and  affection  by  which  every  act  of  his  domestic  life  was 
guided,  prevented  his  little  faults  from  being  perceptible  to  his 
family,  except  at  a  distance;  but  in  touching  on  the  evil  as  well 
as  the  good,  they  feel  sure  they  are  only  doing  what  his  own 
upright  and  manly  mind  would  have  approved. 

The  unguarded  expressions  in  which  it  has  before  been  men- 
tioned that  Mr.  Knight  occasionally  spoke  of  men  and  mea- 
sures, was  also  sometimes  the  cause  of  misconception  as  to  the 
nature  of  his  religious  opinions.  It  was  very  far  from  true 
that  he  disbelieved  the  fundamental  truths  of  Christianity ;  on 
the  contrary,  he  often  referred  to  them  both  as  a  test  of  truth, 
and  a  rule  of  conduct.  He  was  not  attached  to  any  particular 
party  or  sect,  but  always  declared  his  belief  that  all  would  be 
objects  of  Divine  mercy,  whose  actions  and  conversation  were 
controlled  and  directed  by  the  influence  of  Christian  principle. 
He  entered  life  at  a  time  when,  as  the  warmest  supporters  of 


72  LIFE    OF 

the  Church  of  England  admit,  a  lamentable  laxity  prevailed  in 
her  discipline  ;  and  unfortunately  several  strong  cases  of  derelic- 
tion of  duty  in  her  ministers  came  under  his  observation  ;  but 
he  rejoiced  in  the  progressive  improvement  that  has  since  that 
period  been  gradually  accomplished  in  the  habits  of  the  clergy ; 
and  in  discussing  his  favourite  subject,  a  modification  of  the 
tithe  laws,  he  never  failed  to  mention,  as  the  great  object,  the 
advantage  that  would  ensue  from  an  alteration  of  these  laws 
to  the  cause  of  religion :  and  he  always  expressed  himself  de- 
sirous that  the  parochial  clergy  should  generally  be  better  pro- 
vided than  at  present,  with  the  means  of  living  in  comfort 
themselves,  and  of  affording  temporal  assistance  to  their  flocks. 
He  had  himself  originally  been  intended  by  his  family  to  enter 
the  church  ;  but  he  declined  to  accede  to  their  wishes,  from  the 
deep  sense  he  entertained  of  the  responsibility  of  the  duties 
that  such  a  course  would  entail ;  and  when  he  saw  men,  who 
he  believed  had  taken  upon  themselves  the  solemn  vows  of  the 
ordination  service  from  mercenary  motives,  and  whose  conduct 
would  have  been  offensive  in  a  layman,  he  was  in  the  habit  of 
delivering   in  very  strong  terms  his  opinion  of  the  injurious 
fluence   which  such   persons   were  likely  to  exercise  on  the 
spiritual  interests  of  those  committed  to  their  charge :  but  the 
zealous  and  hard-working  clergyman  was  sure  to  receive  from 
him,  not  only  the  warmest  expression  of  approbation  and  re- 
spect, but  every  proof  of  esteem  and  kindness ;  and  those  who 
had  the  charge  of  the  parishes  in  the  neighbourhood  of  Down- 
ton  Castle,  can  testify  how  readily  he  afforded  his  co-operation 
and  assistance  to  every  plan  for  the  relief  and  benefit  of  their 
parishioners. 

By  many  persons,  who  do  not  think  themselves  deficient  in 
religious  principles,  the  evangelical  party  are  made  an  object  of 
ridicule ;  but  in  this  Mr.  Knight  never  joined ;  and  though  he 
might  sometimes  think  the  zeal  of  some  of  its  members  mis- 
directed, he  was  willing  to  give  them  the  full  credit  due  to  good 
intentions ;  and  he  never  would  allow  that  the  adoption  of  a 
higher  rule  of  duty  should  be  a  cause  for  reproach. 


THOMAS    ANDREW    KNIGHT,    ESQ.  73 

His  charities  were  very  extensive,  and  it  was  only  by  chance 
that  those  who  most  shared  his  confidence  became  acquainted 
with  the  large  sums  he  distributed.  It  was  the  spontaneous 
feeling  of  his  heart,  that  it  is  more  blessed  to  give  than  to 
receive ;  and  when  he  bestowed  money  or  did  an  act  of  kindness 
that  caused  him  some  personal  inconvenience,  he  always  endea- 
voured to  make  it  appear,  that  for  some  reason  or  other,  it 
happened  to  be  an  accommodation  to  himself,  and  that  he  was 
the  party  on  whom  the  favour  was  conferred. 

The  indulgence  and  patience  he  evinced  in  conversing  with 
the  ignorant  and  the  dull  was  pre-eminent ;  no  arrogance  of 
manner  ever  displayed  itself  while  arguing  with  an  inferior  dis- 
putant. He  himself  knew  too  much,  not  to  make  ample  allow- 
ance in  others  for  a  want  of  acquaintance  with  any  subjects  which 
he  had  more  particularly  studied ;  and  with  the  greatest 
readiness  he  avowed  his  own  ignorance  when  questioned  as  to 
any  point  on  which  he  did  not  feel  himself  competent  to  afford 
the  desired  information.  When  his  children  were  young,  he 
was  always  ready  to  lay  aside  his  book  to  answer  their  questions, 
or  to  assist  in  their  amusements  ;  he  was  anxious  to  cultivate  in 
them  a  taste  for  horticulture,  natural  history,  and  other  rational 
pursuits ;  and  his  daughters  now  look  back  to  the  hours  spent 
with  him  in  his  study,  or  in  his  garden,  as  among  the  happiest 
recollections  of  their  childhood. 

Even  after  he  had  entered  his  eightieth  year,  it  was  delightful 
to  watch  the  spirit  with  which  he  shared  in  the  sports  of  his 
grandchildren,  and  the  trouble  he  took  to  provide  occupation 
and  amusement  for  them,  and  the  pleasure  which  he  derived 
from  the  success  of  his  labours. 

What  is  said  by  his  sons  of  Mr.  Knight's  favourite  poet, 
Crabbe,  may  be  most  appropriately  applied  to  himself,  "  that  as 
the  chief  characteristic  of  his  heart  was  benevolence,  so  that  of 
his  mind  was  a  buoyant  exuberance  of  thought,  and  a  perpetual 
exercise  of  intellect,  a  youthful  tenderness  of  feeling,  and  a 
smile  of  indescribable  benevolence."  Like  Crabbe,  too,  he  had 
no  great  "  love  for  painting,  or  music,  or  architecture,  and  little 


74  LIFE    OF 

for  what  a  painter's  eye  considers  the  beauty  of  landscape/'  but 
he  had  the  strongest  perception  and  enjoyment  of  the  charms 
of  poetry.  Pope,,  Johnson,  Gray,  and  Crabbe  ranked  first  in 
his  estimation  among  the  English  poets  ;  and  for  the  writings  of 
Byron,  Rogers,  Campbell,  and  Mrs.  Hemans,  he  had  a  high 
admiration.  His  memory  was  wonderfully  retentive,  and  no  one 
who  was  much  in  his  society  could  fail  to  remark  the  peculiar 
readiness  and  aptitude  of  his  quotations.  Whether  the  subject 
of  conversation  were  grave  or  lively,  he  had  always  at  command 
some  strikingly  apposite  illustration  of  ideas  casually  expressed  ; 
and  the  deep  feeling  of  its  beauties  which  characterised  his 
manner  of  reciting  poetry,  added  much  to  the  effect  of  the  pas- 
sages so  happily  selected ;  and  if  encouraged  to  go  on,  he  would 
repeat  page  after  page  of  all  his  favourite  authors. 

The  singular  powers  of  memory  he  possessed  were  combined 
with  a  very  uncommon  facility  for  retaining  even  the  words  in 
which  ideas  were  conveyed  to  his  mind.  On  one  occasion,  at 
the  house  of  his  friend,  the  late  Sir  Uvedale  Price,  a  gentleman 
present  quoted  a  passage  from  Gibbon's  Roman  History ;  Mr. 
Knight  expressed  a  doubt  whether  he  had  used  the  exact  words  of 
Gibbon  ;  and  in  confirmation  of  his  opinion  repeated  a  page  and 
a  half  from  the  work,  including  the  passage  in  question.  On 
the  book  itself  being  referred  to,  the  accuracy  of  his  quotation 
was  established.  This  was  not  a  singular  instance,  for  had  it 
been  Hume,  or  Robertson,  or  almost  any  other  standard  work 
of  history  or  philosophy,  that  had  been  referred  to,  he  would 
probably  have  been  equally  master  of  any  striking  passage. 

At  another  time  Dr.  Cornewall,  then  Bishop  of  Hereford, 
repeated  to  Mr.  Knight  an  epitaph  on  Douglas,  eighth  Duke  of 
Hamilton,  containing  twenty-two  lines,  with  the  merit  of  which 
he  was  much  struck,  and  some  discussion  on  its  beauties  fol- 
lowed. When  Mr.  Knight  came  down  to  breakfast  the  next 
morning,  he  had  recalled  the  whole  of  the  lines  to  his  recollec- 
tion, and  on  their  being  written  down  from  his  dictation,  they 
were  found  to  be  perfectly  correct. 

To  the  end  of  his  life  this  power  of  memory,  which  is  usually 


THOMAS    ANDREW    KNIGHT,    ESQ.  75 

one  of  the  first  that  fails,  remained  almost  unimpaired.  All  that 
he  read  or  heard  his  mind  retained  with  the  same  distinctness 
that  it  would  have  done  in  former  days  ;  and  when  he  was  in 
his  seventy-seventh  year,  he  acquired  by  heart  nearly  the  whole 
of  Campbell's  poem  of  "  The  Last  Man,"  which  he  then  for  the 
first  time  met  with,  with  nearly  the  same  ease  that  he  had  done 
the  epitaph  more  than  thirty  years  before. 

Mr.  Knight's  form  was  muscular  and  powerful,  and  till  his 
last  illness,  and  notwithstanding  his  advanced  age,  his  step  was 
as  firm,  and  his  figure  as  erect,  as  it  had  ever  been,  though  his 
height  was  nearly  six  feet :  his  complexion  was  fair,  and  his 
eyes  blue ;  his  hair  was  light  brown,  but  at  an  early  age  he 
became  bald,  and  the  fine  intellectual  form  of  his  head  was  very 
striking.  His  countenance,  though  not  handsome,  beamed  with 
intelligence  and  benevolence,  and  was  a  type  of  the  qualities  of 
his  mind  and  heart. 

The  limits  of  this  work  will  not  allow  that  a  more  detailed  view 
of  Mr.  Knight's  character  should  be  given  ;  but  if,  among  those 
who  knew  him,  a  good-natured  smile  may  sometimes  have  been 
called  forth  by  any  little  peculiarities,  arising  from  the  origi- 
nality of  his  mind,  his  friends  will  agree  that  few  lives  ever 
abounded  more  in  works  of  kindness  and  charity  than  his,  and 
that  the  object  foremost  in  his  thoughts  was  that  of  making  his 
investigations  into  the  more  abstruse  branches  of  natural  history, 
the  basis  of  designs  for  the  improvement  and  benefit  of  his 
fellow-creatures. 

Had  the  task  of  delineating  his  character  fallen  into  other 
hands,  his  family  would  have  rejoiced  ;  and  it  will  be  a  source 
of  deep  and  lasting  regret,  if  the  inability  they  strongly  feel  to 
do  justice  to  his  noble  nature,  should  have  caused  him  to  appear 
to  those  who  had  not  the  happiness  of  knowing  him  less  wise 
and  good  than  he  was. 


76  LIFE    OF 


LIST  OF  MEDALS  PRESENTED  TO  MR.  KNIGHT. 

1806— Royal  Society  Gold  Copley  Medal. 

1814— Horticultural  Society  Gold  Medal. 

1815 — Large  Silver  Medal  for  Black  Eagle  Cherry. 

1817— Do.     do.,      for  Waterloo  Cherry. 

1818— Do.     do.,      for  Elton  Cherry. 

1822 — Silver  Banksian  Medal  for  new  Pears. 

1836— New  large  Gold  Medal. 

1801— Society  of  Arts  Silver  Medal  for  Turnip  Drill. 

1815 — Caledonian  Horticultural  Society  Gold  Medal,  "In  testimony  of  their 
gratitude  for  his  valuable  discoveries,  the  result  of  patient  and  labo- 
rious research  in  Vegetable  Physiology — science  having  been  his  guide." 

1826 — Massachusetts  Agricultural  Society  Medal.  (A  circular  plate  of  silver, 
two  inches  and  a  quarter  in  diameter, ^inscribed)  "  The  Massachusetts 
Society  for  Promoting  Agriculture,  to  Thomas  Andrew  Knight,  Esq. 
of  Downton  Castle,  England,  as  a  tribute  to  an  eminent  Physiologist, 
and  a  benefactor  to  the  new  world." 

1830 — Swedish  Academy  of  Agriculture,  "  Grand  Silver  Medal." 


LIST  OF  SOCIETIES  OF  WHICH  MR.  KNIGHT  WAS  A  MEMBER. 

1804— Royal  Society  of  London. 

1804— Royal  Society  of  Edinburgh. 

1804 — Horticultural  Society  of  London. 

1825 — Hon.  Member  of  Royal  Botanical  Society  of  Glasgow.     Hon.  Member 

of  Medico-Botanical   Society,    London.      Hon.   Associate   of  Ycrulam 

Society  of  London. 

1818 — Hon.  Member  of  Society  of  Naturalists  of  Berlin. 
1820 — Hon.  Member  of  Horticultural  Society  of  Potsdam. 
1822 — Hon.  Member  of  Literary  and  Philosophical  Society  of  New  York. 
1822 — Hon.  Member  of  New  York  County  Agricultural  Society. 
]  822 —Hon.  Member  of  New  York  Historical  Society. 
1822 — Hon.  Member  of  Massachusetts  Agricultural  Society. 
1823 — Corresponding  Member  of  Prussian  Horticultural  Society. 
1824 — Corresponding  Member  of  Columbian  Horticultural  Society. 
1824 — Corresponding  Member  of  the  Pomological  Society  of  Guben. 
1828  —Hon.  Member  of  Swedish  Agricultural  Society. 
1829 — Hon.  Member  of  Imperial  Natural  History  Society  of  Moscow. 
1829 — Hon.  Member  of  Horticultural  Society  of  the  Departement  du  Nord 

(France). 


THOMAS    ANDREW    KNIGHT,    ESQ.  77 

J832 — Hon.  Member  of  Agricultural  Society  of  Western  Australia. 

1832 — Hon.  Corresponding  Member  of  '  La  Sociedad  Patriotica  de  la  Habana. 

1833 — Hon.  Member  of  Horticultural  Society  of  Charleston. 

1833 — Hon.  Member  of  Lower  Canada  Horticultural  Society. 

1834 — Hon.  Member  of  South  Carolina  Horticultural  Society. 


The  following  list  contains  most  of  the  new  varieties  of  fruits 
raised  by  Mr.  Knight,  which  he  considered  worth  preserving : 

Apples. — Spring-grove  Codling.  Downton  Lemon  Pippin.  Herefordshire 
Gillyflower.  Grange  Apple,  &c. 

Cherries. — Elton,  Waterloo  and  Black  Eagle. 

Strawberries. — Elton  and  Downton. 

A  large  and  long-keeping  red  Currant. 

Plums. — Ickworth  Imperatrice. — A  large  purple  Plum  not  named,  and  two 
improved  Damsons. 

Nectarines. — Imperatrice,  Ickworth,  Downton,  and  Althorp. 

Pears — Monarch,  Althorp  Cressane,  Rouse  Level,  Winter  Cressane,  Bel- 
rnont,  and  many  others. 

Many  excellent  and  productive  varieties  of  Potatoes,  of  which  the  only  one 
named  is  the  Downton  Yam. 

The  Knight  Pea,  and  improved  varieties  of  Cabbage. 


IN  making  the  following  selection  from  the  numerous  communications  ad- 
dressed by  Mr.  Knight  to  the  Royal  and  Horticultural  Societies,  the  object 
kept  in  view  has  been  to  embody  the  whole  of  those  which  give  an  account  of 
the  important  physiological  experiments  carried  on,  or  facts  observed  by  him, 
or  in  which  are  consigned  the  theoretical  or  practical  results  deduced  from  these 
experiments  and  observations.  Those  relating  to  temporary,  controversial  or 
other  matters,  now  deprived  of  the  interest  they  possessed  at  the  time  when 
read,  are  here  omitted. 

In  the  arrangement  of  the  papers,  it  has  been  thought  best  to  adopt  the 
chronological  order :  thus  showing  the  gradual  steps  attained  by  Mr.  Knight  in 
the  pursuit  of  his  inquiries,  and  simplifying  the  references  he  was  in  the  habit 
of  making  to  previous  memoirs.  This  order  has  only  been  departed  from  in  as 
far  as  was  necessary  to  separate  the  communications  made  to  the  Royal  Society 
from  those  made  to  the  Horticultural  Society ;  for  it  has  appeared  as  if  Mr. 
Knight's  object,  in  determining  to  which  body  he  should  address  himself,  was 
to  place  on  record,  in  the  Philosophical  Transactions,  the  general  physiological 
principles  he  laid  down,  and  in  the  Horticultural  Transactions  to  detail  the 
practical  application  of  those  principles. 

Three  papers  on  questions  of  Animal  Economy,  of  considerable  importance, 
but  not  immediately  connected  with  Horticulture,  or  Vegetable  Physiology, 
are  given  in  an  Appendix. 


PART  I. 
PAPERS  ON   VEGETABLE   PHYSIOLOGY, 


READ   BEFORE 


THE    ROYAL    SOCIETY,    IN   THE   YEARS  1795  TO  1816. 


REPRINTED  FROM   THE  PHILOSOPHICAL    TRANSACTIONS. 


I.— OBSERVATIONS     ON    THE    GRAFTING     OF    TREES. 

[Read  before  the  ROYAL  SOCIETY  April  30th,  1795.] 

THE  disease  from  whose  ravages  apple  and  pear  trees  suffer  most  is  the 
canker ;  the  effects  of  which  are  generally  first  seen  in  the  winter,  or 
when  the  sap  is  first  rising  in  the  spring.  The  bark  becomes  discoloured 
in  spots,  under  which  the  wood,  in  the  annual  shoots,  is  dead  to  the 
centre ;  and,  in  the  older  branches,  to  the  depth  of  the  last  summer's 
growth.  Previous  to  making  any  experiments,  I  had  conversed  with 
several  planters,  who  entertained  an  opinion,  that  it  was  impossible  to 
obtain  healthy  trees  of  those  varieties  which  flourished  in  the  beginning 
and  middle  of  the  present  century,  and  which  now  form  the  largest  orchards 
in  this  county  (Herefordshire).  The  appearance  of  the  young  trees,  which 
I  had  seen,  justified  the  conclusion  they  had  drawn ;  but  the  silence  of 
every  writer  on  the  subject  of  planting,  which  had  come  in  my  way, 
convinced  me  it  was  a  vulgar  error,  and  the  following  experiments  were 
undertaken  to  prove  it  so. 

I  suspected  that  the  appearance  of  decay  in  the  trees  I  had  seen  lately 
grafted,  arose  from  the  diseased  state  of  the  grafts,  and  concluded  that 
if  I  took  scions  or  buds  from  trees  grafted  in  the  year  preceding,  I  should 
succeed  in  propagating  any  kind  I  chose.  With  this  view,  I  inserted 
some  cuttings  of  the  best  wood  I  could  find  in  the  old  trees,  on  young 
stocks  raised  from  seed.  I,  again,  inserted  grafts  and  buds  taken  from 
these  on  other  young  stocks,  and,  wishing  to  get  rid  of  all  connexion 
with  the  old  trees,  I  repeated  this  six  years  ;  each  year  taking  the  young 


82  OBSERVATIONS    ON    THE    GRAFTING    OF    TREES. 

shoots  from  the  trees  last  grafted.  Stocks  of  different  kinds  were  tried ; 
some  were  double-grafted,  others  obtained  from  apple-trees  which  grew 
from  cuttings,  and  others  from  the  seed  of  each  kind  of  fruit  afterwards 
inserted  on  them.  I  was  surprised  to  find  that  many  of  these  stocks 
inherited  all  the  diseases  of  the  parent  trees. 

The  wood  appearing  perfect  and  healthy  in  many  of  my  last-grafted  trees, 
I  flattered  myself  that  I  had  succeeded  ;  but  my  old  enemies,  the  moss 
and  canker,  in  three  years  convinced  me  of  my  mistake.  Some  of  them, 
however,  trained  to  a  south  wall,  escaped  all  their  diseases,  and  seemed 
(like  invalids)  to  enjoy  the  benefit  of  a  better  climate.  I  had  before 
frequently  observed,  that  all  the  old  fruits  suffered  least  in  warm  situa- 
tions, where  the  soil  was  not  unfavourable.  I  tried  the  effects  of  laying 
one  kind,  but  the  canker  destroyed  it  at  the  ground.  Indeed  I  had  no 
ht>pe  of  success  from  this  method ;  as  I  had  observed  that  several  sorts, 
which  had  always  been  propagated  from  cuttings,  were  as  much  diseased 
as  any  others.  The  wood  of  all  the  old  fruits  has  long  appeared  to  me 
to  possess  less  elasticity  and  hardness,  and  to  feel  more  soft  and  spongy 
under  the  knife,  than  that  of  the  new  varieties  which  I  have  obtained 
from  seed.  This  defect  may,  I  think,  be  the  immediate  cause  of  the 
canker  and  moss,  though  it  is  probably  itself  the  effect  of  old  age,  and 
therefore  incurable. 

Being  at  length  convinced  that  all  efforts  to  make  grafts  from  w7orn- 
out  trees  were  ineffectual,  I  thought  it  probable  that  those  taken  from 
very  young  trees  raised  from  seed  could  not  be  made  to  bear  fruit. 
The  event  here  answered  my  expectation.  Cuttings  from  seedling  apple- 
trees  of  two  years  old  were  inserted  on  stocks  of  twenty,  and  in  a  bearing 
state.  These  have  now  been  grafted  nine  years  ;  and  though  they  have 
been  frequently  transplanted  to  check  their  growth,  they  have  not  yet 
produced  a  single  blossom.  I  have  since  grafted  some  very  old  trees 
with  cuttings  from  seedling  apple-trees  of  five  years  old :  their  growth 
has  been  extremely  rapid,  and  there  appears  no  probability  that  their 
time  of  producing  fruit  will  be  accelerated,  or  that  their  health  will  be 
injured,  by  the  great  age  of  the  stocks.  A  seedling  apple-tree  usually 
bears  fruit  in  thirteen  or  fourteen  years ;  and  I  therefore  conclude,  that 
I  have  to  wait  for  a  blossom  till  the  trees  from  which  the  grafts  were 
taken  attain  that  age ;  though  I  have  reason  to  believe,  from  the  form  of 
their  buds,  that  they  will  all  be  extremely  productive.  Every  cutting, 
therefore,  taken  from  the  apple  (and  probably  from  every  other)  tree, 
will  be  affected  by  the  state  of  the  parent  stock.  If  that  be  too  young 
to  produce  fruit,  it  will  grow  with  vigour,  but  will  not  blossom ;  and  if 


OBSERVATIONS    ON    THE    GRAFTING    OF    TREES.  83 

it  be  too  old,  it  will  immediately  produce  fruit,  but  will  never  make  a 
healthy  tree,  and  consequently  never  answer  the  intention  of  the  planter. 
The  root,  however,  and  the  part  of  the  stock  adjoining  it,  are  greatly 
more  durable  than  the  bearing  branches ;  and  I  have  no  doubt  but  that 
scions  obtained  from  either  would  grow  with  vigour,  when  those  taken  from 
the  bearing  branches  would  not.  The  following  experiment  will,  at  least, 
evince  the  probability  of  this  in  the  pear-tree  : — I  took  cuttings  from  the 
extremities  of  the  bearing  branches  of  some  old  ungrafted  pear-trees, 
and  others  from  scions  which  sprung  out  of  the  trunks  near  the  ground, 
and  inserted  some  of  each  on  the  same  stocks.  The  former  grew  without 
thorns,  as  in  the  cultivated  varieties,  and  produced  blossoms  the  second 
year ;  whilst  the  latter  assumed  the  appearance  of  stocks  just  raised  from 
seeds,  were  covered  with  thorns,  and  have  not  yet  produced  any  blossoms. 

The  extremities  of  those  branches,  which  produce  seeds  in  every  tree, 
probably  show  the  first  indication  of  decay  ;  and  we  frequently  see 
(particularly  in  the  oak)  young  branches  produced  from  the  trunk,  when 
the  old  ones  have  been  dead.  The  same  tree  when  cropped  will  produce 
an  almost  eternal  succession  of  branches.  The  durability  of  the  apple  and 
pear  I  have  long  suspected  to  be  different  in  different  varieties  ;  but  that 
none  of  either  would  vegetate  with  vigour  much,  if  at  all,  beyond  the  life  of 
the  parent  stock,  provided  that  died  from  mere  old  age.  I  am  confirmed 
in  this  opinion  by  the  books  you  did  me  the  honour  to  send  me :  of  the 
apples  mentioned  and  described  by  Parkinson,  the  names  only  remain  ; 
but  many  of  Evelyn's  are  still  well  known,  particularly  the  red-streak. 
This  apple,  he  informs  me,  was  raised  from  seed  by  Lord  Scudamore  in 
the  beginning  of  the  last  century*.  We  have  many  trees  of  it,  but  they 
appear  to  have  been  in  a  state  of  decay  during  the  last  forty  years. 
Some  others  mentioned  by  him  are  in  a  much  better  state  of  vegetation, 
but  they  have  all  ceased  to  deserve  the  attention  of  the  planter.  The 
durability  of  the  pear  is  probably  something  more  than  double  that  of 
the  apple. 

It  has  been  remarked  by  Evelyn,  and  by  almost  every  writer  since,  on 
the  subject  of  planting,  that  the  growth  of  plants  raised  from  seeds  was 
more  rapid,  and  that  they  produced  better  trees  than  those  obtained 
from  layers  or  cuttings.  This  seems  to  point  out  some  kind  of  decay 
attending  the  latter  modes  of  propagation ;  though  the  custom  in  the 
public  nurseries  of  taking  layers  from  stools  (trees  cropped  annually 
close  to  the  ground)  probably  retards  its  effects,  as  each  plant  rises 
immediately  from  the  root  of  the  parent  stock. 

*  Probably  about  the  year  1634. 


ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

Were  a  tree  capable  of  affording  an  eternal  succession  of  healthy 
plants  from  its  roots,  I  think  our  woods  must  have  been  wholly  overrun 
with  those  species  of  trees  which  propagate  in  this  manner,  as  those  scions 
from  the  roots  always  grow  in  the  first  three  or  four  years  with  much 
greater  rapidity  than  seedling  plants.  An  aspen  is  seldom  seen  without 
a  thousand  suckers  rising  from  its  roots ;  yet  this  tree  is  thinly,  though 
universally,  scattered  over  the  woodlands  of  this  country.  I  can  speak  from 
experience,  that  the  luxuriance  and  excessive  disposition  to  extend  itself 
in  another  plant,  which  propagates  itself  from  the  root  (the  raspberry), 
decline  in  twenty  years  from  the  seed.  The  common  elm  being  always 
propagated  from  scions  or  layers,  and  growing  with  luxuriance,  seems  to 
form  an  exception  ;  but,  as  some  varieties  grow  much  better  than  others, 
it  appears  not  improbable  that  the  most  healthy  are  those  which  have  last 
been  obtained  from  seed.  The  different  degrees  of  health  in  our  peach 
and  nectarine  trees  may,  I  think,  arise  from  the  same  source.  The  oak 
is  much  more  long-lived  in  the  north  of  Europe  than  here ;  though  its 
timber  is  less  durable,  from  the  number  of  pores  attending  its  slow 
growth.  The  climate  of  this  country  being  colder  than  its  native,  may, 
in  the  same  way,  add  to  the  durability  of  the  elm ;  which  may  possibly  be 
further  increased  by  its  not  producing  seeds  in  this  climate, — as  the  life 
of  many  animals  may  be  increased  to  twice  its  natural  period,  if  not 
more,  by  preventing  their  seeding. 


II.— ACCOUNT  OF  SOME  EXPERIMENTS  ON  THE  ASCENT  OF  THE  SAP  IN 

TREES. 

[Read  before  the  ROYAL  SOCIETY,  May  Uth,  1801. ] 

THESE  experiments  were  made  on  different  kinds  of  trees  ;  but  I  shall 
confine  myself  to  those  I  have  made  on  the  crab-tree,  the  horse-chestnut, 
the  vine,  and  the  oak  ;  and  shall  begin  with  those  made  on  the  crab-tree. 

Choosing  several  young  trees  of  this  species  in  my  nursery,  of  something 
more  than  half  an  inch  diameter,  and  of  equal  vigour,  I  made  two 
circular  incisions  through  the  bark,  round  one  half  the  number  of  them, 
about  half  an  inch  distant  from  each  other,  early  in  the  spring  of  1799  ; 
and  I  totally  removed  the  bark  between  these  incisions,  scraping  off  the 
external  coat  of  the  wood.  The  other  half  I  left  in  their  natural  state. 

At  the  usual  season,  the  sap  rose  in  equal  abundance  in  all ;  and  their 
branches  shot,  during  the  whole  spring,  with  equal  luxuriance.  But  that 
part  of  the  stems  (of  the  trees  whose  bark  had  been  taken  off)  which  was 


ASCENT    OF    THE    SAP    IN    TREES.  85 

below  my  incisions,  scarcely  grew  at  all,  whilst  all  the  parts  above  the 
incisions  increased  as  rapidly  as  in  the  trees  whose  bark  remained  in  the 
natural  state ;  the  upper  lips  of  the  wounds  also  made  considerable 
advances  towards  a  union,  but  the  lower  ones  made  scarcely  any. 

Soon  after  midsummer,  those  parts  of  the  wood  which  had  been 
deprived  of  bark  became  dry  and  lifeless,  to  some  depth  ;  and  the  sap,  in 
consequence,  meeting  obstruction  in  its  ascent,  some  latent  buds  shot 
forth,  in  some  of  the  plants,  below  the  incisions.  When  one  of  the  shoots 
which  these  buds  produced  was  suffered  to  remain,  the  part  of  the  stem 
below  it  began  immediately  to  increase  in  size  ;  but  if  it  was  at  any  dis- 
tance below  the  incision  above,  the  part  between  it  and  that  incision  still 
remained  very  nearly  stationary,  so  as  to  be,  in  the  autumn,  almost  a 
whole  year's  growth  less  than  the  stem  above  the  incisions. 

Choosing  other  stocks,  which  had  each  a  strong  lateral  branch,  I 
removed  the  bark,  in  the  manner  described,  in  two  places  ;  the  one  above, 
and  the  other  below,  each  lateral  branch.  The  sap  here  passed  both  my 
incisions  as  freely  as  in  the  former  experiment ;  the  lateral  branches 
between  them  grew  with  the  greatest  vigour,  and  the  part  of  the  stem 
between  those  branches  and  the  lower  incisions  increased  much  in  size. 
I  varied  these  experiments  in  every  way  that  occurred  to  me ;  and  the 
result  uniformly  was,  that  those  parts  of  the  stems  and  branches  which 
were  above  the  incisions,  and  had  a  communication  with  the  leaves, 
through  the  bark,  increased  rapidly ;  whilst  those  below  the  incisions 
scarcely  grew  at  all,  till  a  new  communication  with  the  leaves  through 
the  bark  was  obtained,  by  means  of  a  lateral  shoot  below  the  incisions. 
It  now  appeared  to  me  to  be  probable  that  the  current  of  sap  which  adds 
the  annual  layer  of  wood  to  the  stem  must  descend  through  the  bark, 
from  the  young  branches  and  leaves  ;  and  to  these  my  attention  was  in 
consequence  directed. 

Towards  the  end  of  the  summer,  when  some  young  luxuriant  shoots  of 
my  apple-trees  had  attained  a  proper  degree  of  firmness,  I  made  four 
circular  incisions  through  the  bark  of  each,  as  in  the  preceding  instances  ; 
and  I  removed  the  bark  in  two  places,  leaving  a  leaf  between  the  places 
where  the  bark  was  taken  off.  Examining  them  frequently  during  the 
autumn,  I  found  that  the  insulated  leaf  acted  just  as  the  lateral  branch 
had  done ;  the  part  of  the  bark  and  stem  between  it  and  the  lower 
incision  being  apparently  as  well  fed  as  any  other  part  of  the  tree ;  and 
it  grew  as  much.  Making  similar  incisions  on  other  branches  of  the  same 
age,  I  left  similar  portions  of  insulated  bark,  without  a  leaf  between  the 
incisions  ;  but  in  these  no  apparent  increase  in  the  size  of  the  wood  was 
discoverable. 


86  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

I  was  still  unacquainted  with  the  channel  through  which  the  sap  was 
conveyed  into  the  leaf ;  and  therefore,  having  obtained  a  deeply-tinged 
infusion,  by  macerating  the  skins  of  a  very  black  grape  in  water,  I  pre- 
pared some  annual  shoots  of  the  apple  and  of  the  horse-chestnut  in  the 
manner  above  mentioned  ;  then,  cutting  them  off  a  few  inches  below  the 
incisions  of  the  bark,  I  placed  them  for  some  hours  in  the  coloured  infu- 
sion. Making  transverse  sections  of  them  afterwards,  I  found  that  the 
infusion  had  passed  up  the  pores  of  the  wood,  beyond  both  my  incisions, 
and  into  the  insulated  leaves ;  but  it  had  neither  coloured  the  bark,  nor 
the  sap  between  it  and  the  wood  ;  and  the  medulla  was  not  affected,  or 
at  most  was  very  slightly  tinged  at  its  edges. 

My  attention  was  now  turned  to  the  leaves  :  these  in  the  apple-tree 
are  attached  to  the  wood  by  three  strong  fibres  or  tubes,  (or  rather 
bundles  of  tubes,)  one  of  which  enters  the  middle  of  the  leaf-stalk,  and 
the  others  are  on  each  side  of  it.  In  the  horse-chestnut  there  are  seven 
or  eight  bundles  of  a  similar  kind  of  tubes  in  each  leaf ;  through  these 
the  infusion  had  passed,  and  had  communicated  its  colour  to  them, 
through  almost  the  whole  length  of  each  leaf-stalk.  Examining  these 
tubes  more  minutely,  I  found  that  they  were  surrounded  with  others, 
which  were  free  from  colour,  and  appeared  to  be  conveying,  in  one 
direction  or  the  other,  a  different  fluid.  On  tracing  these  downwards,  I 
discovered  that  they  entered  the  inner  bark,  and  had  no  immediate  com- 
munication with  the  tubes  of  the  wood.  I  now  endeavoured,  in  the  same 
manner,  to  trace  back  those  vessels  which  had  carried  the  infusions  into 
the  leaves,  and  I  readily  found  them  to  be  perfectly  distinct  from  the 
common  tubes  of  the  alburnum.  They  commence  a  few  inches  below  the 
leaf  to  which  they  belong,  and  they  become  more  numerous  as  they 
approach  it ;  everywhere  surrounding  the  medulla  in  bundles,  as  repre- 
sented in  plate  i.  To  these  vessels  the  spiral  tubes  are  everywhere 
appendages.  I  do  not  know  that  any  specific  name  has  been  given  to 
these  vessels ;  and,  therefore,  as  they  constitute  a  centre,  round  which 
the  future  alburnum  is  formed  in  the  succulent  annual  shoot,  I  will  call 
them  the  central  vessels,  to  distinguish  them  from  the  spiral  tubes  and 
the  common  tubes  of  the  wood.  In  plates  n.  and  in.  the  direction  of 
these  vessels,  with  the  spiral  tubes,  in  their  passage  from  the  sides  of  the 
medulla  to  the  leaf-stalk,  is  delineated  in  a  transverse  and  longitudinal 
section  ;  they  extend  to  the  extremities  of  the  leaf,  where  I  believe  they 
terminate.  Plate  iv.  presents  two  sections  of  the  leaf-stalk  of  the 
horse-chestnut ;  the  first  being  taken  from  the  middle  of  the  stalk,  and 
the  second  from  its  base.  Lying  parallel  with,  and  surrounding  the  above- 


ASCENT    OF    THE    SAP    IN    TREES.  87 

mentioned  vessels,  appear  other  vessels,  which,  I  conclude,  return  the  sap 
to  the  tree :  for  when  a  leaf  was  cut  off  which  had  imbibed  a  coloured 
infusion,  I  found  that  the  native  juices  of  the  plant  flowed  from  these 
vessels,  apparently  unaltered,  as  has  been  remarked  by  Dr.  Darwin. 
These  vessels  descend  through  the  inner  bark,  (as  delineated  in  plates 
i.,  ii.,  and  in.)  and  appear  to  extend  from  the  extremities  of  the  leaves  to 
the  points  of  the  roots. 

The  whole  of  the  fluid,  which  passed  from  the  wood  to  the  leaf,  seems 
to  me  evidently  to  be  conveyed  through  a  single  kind  of  vessel ;  for  the 
spiral  tubes  will  neither  carry  coloured  infusions,  nor  in  the  smallest 
degree  retard  the  withering  of  the  leaf,  when  the  central  vessels  are 
divided.  But  the  annexed  figures  appear  to  point  out  at  least  two  kinds 
of  returning  vessels.  And  I  think  it  by  no  means  improbable  that  two 
kinds  exist  with  distinct  offices ;  for  there  is  a  new  layer  of  alburnum 
and  a  new  internal  bark  to  be  formed.  I  have,  however,  seen  it  asserted 
somewhere,  in  the  writings  of  Linnaeus  and  other  naturalists,  that  the 
internal  bark  is  annually  converted  into  alburnum.  But  this  is  totally 
erroneous ;  and  a  vigorous  shoot  of  the  apple-tree  often  presents  in  its 
transverse  sections,  when  three  or  four  years  old,  as  many  layers  in  its 
bark,  each  of  which  once  formed  its  internal  vascular  lining. 

As  the  bark  appeared  to  me  now  to  receive  its  nutrition  through  the 
leaf,  I  wished  to  see  what  effect  would  be  produced  by  gradually  reducing 
the  quantity  of  the  leaves.  I  had  a  luxuriant  shoot  of  the  vine  in  my 
vinery,  exactly  in  the  stage  of  growth  I  wanted  ;  and  this  branch  there- 
fore was  towards  its  point  every  day  deprived  of  a  small  portion  of  its 
leaf.  The  bark,  in  consequence,  became  shrivelled  and  dry;  and  at 
length  the  buds  below  vegetated,  and  the  point  of  the  shoot  died,  appa- 
rently from  the  want  of  nourishment.  I  here  observed,  as  I  had  frequently 
done  before,  that  almost  the  whole  action  of  each  leaf  lies  between  itself 
and  the  root ;  for  the  branch,  in  this  case,  was  perfectly  well  fed  below 
the  uppermost  unmutiiated  leaf,  but  failed  immediately  above  it. 

Every  branch  in  which  I  had  yet  attempted  to  trace  the  progress  of 
the  sap  having  contained  its  medulla  uninjured,  the  action  of  that  sub- 
stance next  engaged  my  attention,  and  I  made  the  following  experiments 
on  the  vine  : — Having  made  a  passage  about  half  an  inch  long,  and  a  line 
wide,  into  a  strong  succulent  shoot  of  this  plant,  I  totally  extracted  its 
medulla,  as  far  as  the  orifice  I  had  made  would  permit  me.  But  the 
shoot  grew  nearly  as  well  as  the  others  whose  medulla  had  remained 
uninjured,  and  the  wound  soon  healed.  Making  a  similar  passage,  but 
of  greater  length,  so  that  part  extended  above,  and  part  below,  a  leaf  and 


88  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

bud,  I  again  extracted  the  medulla.  The  leaf  and  bud  with  the  lateral 
shoot  annexed  (in  the  vine)  continued  to  live,  and  did  not  appear  to 
suffer  much  inconvenience,  but  faded  a  little  when  the  sun  shone  strongly 
on  them. 

I  was  now  thoroughly  satisfied  that  the  medulla  was  not  necessary  to 
the  progression  of  the  sap ;  but  I  wished  to  see  whether  the  wood  and 
leaf  could  execute  their  office  when  deprived  at  once  of  the  bark  and 
medulla.  With  this  view,  I  made  two  circular  incisions  through  the 
bark,  above  and  below  a  leaf;  and  I  took  off  the  whole  of  the  bark 
between  them  except  a  small  portion  round  the  base  of  the  leaf.  Having 
then  perforated  the  wood,  where  I  made  each  of  my  incisions  through 
the  bark,  I  destroyed  the  medulla  in  each  place,  as  in  the  preceding  ex- 
periments. The  leaf,  however,  continued  fresh  and  vigorous ;  and  a  thin 
layer  of  new  wood  was  formed  round  its  base,  as  far  as  the  bark  had 
been  suffered  to  remain. 

Whilst  I  was  waiting  the  result  of  the  preceding  experiments,  I  made  a 
few  efforts  to  discover  another  branch  of  circulation,  namely,  that  which  takes 
place  within  the  fruit,  and  conveys  nourishment  to  the  future  offspring. 
My  experiments  were  here,  however,  confined  almost  entirely  to  two  species 
of  fruit,  the  apple  and  the  pear ;  and  therefore,  as  the  organization  of 
different  fruits  is  evidently  different,  I  do  not  consider  my  observations 
such  as  can  throw  much  general  light  on  the  subject.  Examining  the 
fruit-stalks  of  the  apple,  the  pear,  the  vine,  and  some  other  fruit-trees,  I 
found  their  organization  to  be  nearly  similar  to  that  of  the  branch  from 
which  they  sprang,  and  to  consist  of  the  medulla,  the  central  tubes,  a 
very  small  portion  of  wood,  the  spiral  tubes  and  those  of  the  bark,  and 
the  two  external  skins.  Tracing  the  progress  of  these  in  the  full-grown 
fruits  of  the  apple  and  pear,  I  found,  as  Linnaeus  has  described,  that  the 
medulla  appeared  to  end  in  the  pistilla.  The  central  vessels  diverged 
round  the  core,  and,  approaching  each  other  again  in  the  eye  of  the  fruit, 
seemed  to  end  in  ten  points  at  the  base  of  the  stamina,  to  which,  I  believe, 
they  give  existence.  The  spiral  tubes,  which  are,  in  all  other  parts 
appendages  to  these  vessels,  I  could  not  trace  beyond  the  commencement 
of  the  core ;  but  as  the  vessels  themselves  extend  through  the  whole 
fruit,  it  is  probable  that  the  spiral  tubes  may  have  escaped  my  observa- 
tion. Linnaeus  supposes  the  stamina  to  arise  from  the  wood.  I  should 
not  venture  to  state  an  opinion  in  opposition  to  his  ;  but  I  believe  he  has 
not  anywhere  distingushed  those  I  call  the  central  vessels,  from  the  com- 
mon tubes  of  the  wood. 

Having  hitherto  found  that  all  advancing  fluids  appeared  to  pass  either 


ASCENT   OF    THE    SAP    IN    TREES.  89 

along  the  tubes  of  the  alburnum,  or  along  the  central  vessels,  I  had  little 
doubt  that  the  fruit  was  fed  through  the  latter ;  but  my  efforts  to  ascer- 
tain this,  in  the  autumn  of  1799,  were  not  successful.     In  the  last  spring 
I  was  more  fortunate.     Placing  small  branches  of  the  apple,  the  pear, 
and  the  vine,  with  blossoms  not  yet  expanded,  in  a  decoction  of  logwood, 
I  found  that  the  colouring  matter  readily  passed  up  the  central  tubes  of 
the  fruit-stalks  of  all ;  and  in  the  apple  and  pear,  I  easily  traced  it, 
through  the  future  fruit,  to  the  base  of  the  stamina.     The  office  of  the 
tubes  in  the  bark  did  not  appear  in  this  experiment;  but   as  I  have 
reason  to  believe  the  motion  of  the  sap  in  the  bark  to  be  always  retro- 
grade, I  am  disposed  to  conclude  that  it  is  so  here,  and  that,  through  the 
bark  of  the  stalk,  any  superfluous  humours  existing  in  the  fruit,  from 
excessive  humidity  of  weather,  or   other   cause,  are  carried  back,    and 
absorbed  by  the  tree.     I  have,  however,  very  frequently  repeated  an 
experiment  on  the  vine,  which,  I  think,  evidently  proves  that  the  fluid 
returned  (if  any),  is  essentially  different  from  that  which  is  derived  from 
the  leaf.     In  the  culture  of  this  fruit,  I  have  frequently  pinched  off  the 
young    shoot,    immediately    above    a  branch,    as    soon    as   the    latter 
became  visible  in  the  spring,  letting  the  leaf  opposite  the  bunch  remain. 
In  this  case,  the  wood  below  the  upper  leaf  acquired  nearly  its  proper 
length  and  substance.     But  when  I  have  taken  off  that  leaf,  the  wood 
between  the  bunch  and  the  next  leaf  below,  has  ceased  to  elongate  ;  and 
has  remained,   in  form  and   substance,  similar  to  the  small  fruit-stalk 
attached  to  it. 

I  was  long  at  a  loss  to  conjecture  by  what  means  nutrition  was  con- 
veyed to  the  seeds  of  the  apple  and  pear  ;  for  I  had  reason  to  believe  that 
it  was  not  done  by  the  medulla ;  and  I  had  previously  ascertained  that 
the  seeds  would  derive  nourishment  from  the  pulp,  when  the  fruit  was 
taken  prematurely  from  the  tree.  At  length,  in  a  large  apple,  which  was 
just  beginning  to  decay,  I  found  a  number  of  minute  vessels,  leading  from 
the  pulp  to  the  tubes  which  originally  constituted  the  lower  parts  of  the 
pistilla,  and  to  which  the  seeds  are  attached.  These  now  appeared  to 
me  evidently  to  be  the  channels  of  nutrition  to  the  seeds ;  and  since  I 
have  known  what  I  have  to  look  for,  I  find  these  vessels  sufficiently  visible 
in  every  apple :  there  are,  however,  five  other  tubes,  which  pass  alon^ 
the  external  edges  of  the  cells  of  the  core,  to  which  I  do  not  venture  to 
assign  an  office.  It  appears  to  me  not  very  improbable,  that  the  internal 
organization  of  this  fruit  will  be  found  to  bear  some  resemblance  to  the 
placenta  and  umbilical  cord  of  the  animal  economy.  If  transverse  and 
longitudinal  sections  of  young  apples  and  pears  be  made,  soon  after  the 


90  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

blossom  has  fallen,  the  pulp  will  appear  to  be  of  two  kinds  :  one  of  which 
is  included  within  the  vessels  which  carry  up  coloured  infusions  ;  and  this 
seems  to  be  formed  by  continuation  of  the  vessels  and  fibres  within  the 
wood.  The  other  part  appears  to  belong,  in  a  great  measure,  to  the 
bark :  it  is  in  very  small  quantity  in  the  very  young  fruit ;  but,  at  its 
maturity,  it  constitutes  much  the  greater  part  of  the  pulp.  The  vessels, 
however,  which  diverge  into  the  external  pulp,  and  probably  convey 
nourishment  to  it,  appear  to  be  continuations  of  the  central  vessels,  every 
where,  I  believe,  accompanied,  as  in  the  leaf,  with  minute  ramifications  of 
the  tubes  of  the  bark.  The  substance  of  the  core  is  similar  to  that  of 
the  silver  grain  of  the  wood,  of  which  it  may  possibly  be  a  continuation. 

The  force  with  which  the  sap  has  been  proved  to  ascend,  by  Hales, 
banishes  every  idea  of  mere  capillary  attraction.  The  action  of  the  spiral 
tubes  appears  much  more  adequate  to  the  effects  produced,  and  I 
readily  admit  the  supposed  action  of  these,  wherever  they  are  found ;  but 
I  have  so  often  attentively  searched  in  vain  for  them,  with  glasses  of 
different  powers,  in  the  root,  in  the  alburnum,  and  in  the  bark,  that  I 
cannot  but  question  their  existence  in  those  parts.  Attached  to  the 
central  vessels,  in  the  annual  shoot,  in  the  fruit-stalk  of  different  trees,  in 
the  tendril  of  the  vine,  in  the  leaf,  and  in  the  seed,  the  spiral  tubes  cer- 
tainly exist,  and  are  in  most  cases  visible  without  the  aid  of  a  lens.  But 
as  I  have  not  been  able  to  discover  them  in  other  parts  of  the  tree,  and 
as  the  different  authors  I  have  looked  into  have  not  distinguished  those  I 
call  the  central  vessels  from  the  common  tubes  of  the  alburnum,  nor 
marked  the  difference  in  the  organization  of  the  annual  branch  and 
annual  root,  I  must  venture  to  call  their  accuracy  here  in  question, 
though  with  great  deference  for  their  opinions. 

Linnaeus  and  others  have  attempted  to  account  for  the  ascent  of  the 
sap,  by  the  expansion  of  the  fluids  within  the  vessels  of  the  plant,  by  the 
agency  of  heat.  But  the  sap  rises  under  a  decreasing,  as  well  as  under 
an  increasing  temperature,  during  the  evening  and  night  (if  it  be  not 
excessively  cold),  as  well  as  in  the  morning  and  at  noon  ;  and  it  is  suffi- 
ciently evident,  that  the  heat  applied  to  the  branches  of  a  vine  within  the 
stove,  cannot  expand  the  fluids  in  the  stems  and  roots,  which  grow  on  the 
outside.  It  is  also  well  known,  that  the  degree  of  heat  required  to  put 
the  sap  into  motion,  in  this  plant,  is  not  definite,  but  depends  on  that  to 
which  the  plant  has  been  previously  accustomed.  Thus  a  vine,  which  has 
grown  all  the  summer  in  the  heat  of  a  stove,  will  not  be  made  to  vegetate 
during  the  winter  by  the  heat  of  that  stove  ;  but,  if  another  plant  of  the 
same  variety,  which  has  grown  in  the  open  air,  be  at  any  time  introduced, 


ASCENT    OF    THE    SAP    IN    TREES.  91 

after  it  has  dropped  its  leaves  in  the  autumn,  it  will  instantly  vegetate. 
This  effect  appears  to  me  to  arise  from  the  latter  plant's  possessing  a 
degree  of  irritability,  which  has  been  exhausted  in  the  former,  by  the 
heat  of  the  stove,  but  which  it  will  acquire  again  during  the  winter,  or  by 
being  drawn  out,  and  exposed  for  a  short  time  to  the  autumnal  frost. 
On  the  same  principle,  we  may  point  out  the  cause  why  seedling  plants 
always  thrive  better  in  the  spring  than  in  the  autumn,  though  the  weather 
be  apparently  less  favourable.  In  the  former  season,  the  stimulus  of  heat 
and  light  is  gradually  becoming  greater  than  that  to  which  the  plant  has 
been  accustomed  ;  in  the  latter  season,  it  becomes  gradually  less. 

There  is  another  circumstance  attending  trees  that  have  been  made  to 
blossom  early  in  the  preceding  spring,  which  has  always  appeared  to  me 
an  extremely  interesting  one.  If  a  peach-tree,  for  example,  be  brought 
into  blossom  in  one  season  in  the  beginning  of  February,  by  artificial  heat, 
it  will  spontaneously  show  strong  marks  of  vegetation  at  the  approach  of 
that  season  in  the  succeeding  year ;  and,  if  it  be  not  well  protected,  it 
will  expose  its.  blossoms  to  almost  inevitable  destruction.  I  do  not  see 
any  cause  to  which  this  effect  can  be  attributed,  except  to  the  accumu- 
lated irritability  of  the  plant. 

That  heat  is  the  remote  cause  of  the  ascent  of  the  sap  cannot,  I  think, 
be  doubted ;  and,  perhaps,  frequent  variations  of  it  are,  in  some  degree, 
requisite ;  (for  plants  have  always  appeared  to  me  to  thrive  best  with 
moderate  variations  of  temperature ;)  but  the  immediate  cause  will,  I 
think,  be  found  in  an  intrinsic  power  of  producing  motion,  inherent  in 
vegetable  life  ;  and  I  hope  to  be  able  to  point  out  an  agent,  by  which  the 
mechanical  force  required  may  possibly  be  given. 

There  is,  you  know,  in  every  kind  of  wood,  what  workmen  call  its  grain, 
consisting  of  two  kinds,  the  false  or  bastard,  and  the  true  or  silver  grain. 
The  former  consists  of  those  concentric  circles  which  mark  the  annual 
increase  of  the  tree  ;  and  the  latter  is  composed  of  thin  laminae,  diverging 
in  every  direction  from  the  medulla  to  the  bark,  having  little  adhesion  to 
each  other  at  any  time,  and  less  during  the  spring  and  summer  than  in 
the  autumn  and  winter ;  whence  the  greater  brittleness  of  the  wood  in 
the  former  seasons.  These  laminae  (which  are  of  different  width  in  dif- 
ferent kinds  of  wood)  lie  between,  and  press  on,  the  sap  vessels  of  the 
alburnum  ;  they  are  visible  in  every  wood  that  I  have  had  an  opportunity 
to  examine,  except  some  of  the  palm  tribe  ;  and  these  appear  to  me  to 
have  peculiar  organs,  to  answer  a  similar  purpose.  If  you  will  examine  a 
piece  of  oak,  you  will  find  the  laminae  I  describe ;  and  that  every  tube  is 
touched  by  them  at  short  distances,  and  slightly  diverted  from  its  course. 


92  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

If  these  are  expansible  under  changes  of  temperature,  or  from  any  cause 
arising  from  the  powers  of  vegetable  life,  I  conceive  that  they  are  as  well 
placed  as  is  possible  to  propel  the  sap  to  the  extremities  of  the  branches ; 
and  their  restless  temper,  after  the  tree  has  ceased  to  live,  inclines  me  to 
believe  that  they  are  not  made  to  be  idle  whilst  it  continues  alive. 

I  shall  at  present  confine  my  observations  to  the  English  oak,  though 
the  same  are  applicable,  in  a  greater  or  less  degree,  to  every  other  kind 
of  wood.  In  sawing  this  tree  into  boards,  it  is  usual  to  cut  it,  as  much 
as  possible,  into  what  are  called  quarter-boards  ;  which  are  so  named 
because  the  tree  is  first  cut  into  quarters.  In  a  perfect  board  of  this  kind, 
the  saw  exactly  follows  the  direction  in  which  the  tree  most  readily  divides 
when  cloven :  in  this  case,  the  laminae  of  the  silver  grain  lie  parallel  with 
the  surface  of  the  board ;  and  a  board  thus  cut,  when  properly  laid  on 
the  floor,  is  rarely  or  never  seen  to  deviate  from  its  true  horizontal 
position.  If,  on  the  contrary,  one  be  sawed  across  the  silver  grain,  it 
will,  during  many  years,  be  incapable  of  bearing  changes  of  temperature 
and  of  moisture  without  being  warped ;  nor  will  the  strength  of  numerous 
nails  be  sufficient  entirely  to  prevent  the  inconvenience  thence  arising. 
That  surface,  of  a  board  of  this  kind,  which  grew  nearest  the  centre  of 
the  tree,  will  always  show  a  tendency  to  become  convex,  and  the  opposite 
one  concave,  if  placed  in  a  situation  where  both  sides  are  equally  exposed 
to  heat  and  moisture.  You  may  probably  have  observed,  that  when  an 
oak  has  been  deprived  of  its  bark,  and  exposed  to  the  sun  and  air,  its 
surface  has  been  everywhere  covered  with  small  clefts.  These  are  always 
formed  by  the  laminae  of  the  silver  grain  having  parted  from  each  other ; 
and  they  will  long  continue  to  open  and  close  again  with  the  changes  of 
the  weather.  In  the  last  summer,  I  very  frequently  placed  pieces  of  oak, 
recently  deprived  of  its  bark,  in  a  situation  where  it  was  fully  exposed  to 
the  sun,  but  defended  from  rain.  The  surface  of  the  tree,  in  a  few  hours, 
presented  a  great  number  of  small  clefts,  into  which  I  put,  in  the  middle 
of  the  day,  the  points  of  small  iron  pins.  Examining  these  late  in  the 
evening,  I  found  that  the  wood  closed  so  much  as  to  hold  them  firmly, 
and,  early  in  the  next  morning,  they  were  not  easily  withdrawn ;  but  as 
the  influence  of  the  sun  increased,  the  clefts  again  gradually  opened,  as 
in  the  preceding  day,  and  the  pins  always  dropped  out.  I  could  never 
discover  that  any  weight  was  gained  by  the  wood  during  the  night ;  but 
I  was  not  provided  with  a  balance  of  proper  sensibility  to  ascertain  this 
point.  This  experiment  was  frequently  repeated,  and  always  with 
precisely  the  same  result.  After  long  exposure  to  the  air  and  light,  the 
wood  loses  this  property. 


ASCENT    OF    THE    SAP    IN    TREES.  93 

If  the  motion  I  have  supposed  the  silver  grain  to  possess,  in  the  living 
tree,  be  more  than  you  think  can  be  properly  admitted  to  belong  to 
vegetable  life,  I  will  request  your  attention  to  the  power  of  moving  in  the 
vine  leaf,  on  which  I  have  made  many  experiments.  It  is  well  known 
that  this  organ  always  places  itself  so  that  the  light  falls  on  its  upper 
surface  ;  and  that,  if  moved  from  that  position,  it  will  immediately 
endeavour  to  regain  it :  but  the  extent  of  the  efforts  it  will  make,  I 
have  not  anywhere  seen  noticed.  I  have  very  frequently  placed  the  leaf 
of  a  vine  in  such  a  position,  that  the  sun  has  shone  strongly  on  its  under 
surface ;  and  I  have  afterwards  put  obstacles  in  its  way,  on  whichever 
side  it  attempted  to  escape.  In  this  position  the  leaf  has  tried  almost 
every  method  possible  to  turn  its  proper  surface  to  the  light ;  and  I  have 
several  times  seen  one  which,  having  tried  during  several  days  to 
approach  the  light  in  one  direction,  and  having  nearly  covered  its  under 
surface,  by  bending  its  angular  points  almost  to  touch  each  other,  has 
unfolded  itself  again,  and  receded  farther  from  the  glass,  to  approach 
the  light  in  an  opposite  direction.  As  the  whole  effect  here  produced 
appears  to  arise  merely  from  the  light  falling  on  the  under  surface  of  the 
leaf,  I  cannot  conceive  how  the  contortions  of  its  stalk,  in  every  direction, 
can  be  accounted  for,  without  admitting,  not  only  that  the  plant  possesses 
an  intrinsic  power  of  moving,  but  that  it  also  possesses  some  vehicle  of 
irritation ;  and,  without  this,  it  will  I  think  be  difficult  to  explain  how 
the  heat  applied  to  the  branch  of  the  vine,  within  the  stove,  can  put  the 
sap  in  the  roots  and  external  stem  into  motion.  It  may  be  objected, 
that  these  are  always  ready  when  the  branch  calls  for  nourishment, 
and  that  they  are  no  way  affected  by  the  internal  heat.  But  this  I 
cannot  admit  to  be  the  case  ;  because  I  have  found  that  the  stem 
suddenly  becomes  extremely  susceptible  of  injury  from  cold,  as  soon  as 
the  branch  begins  to  vegetate  ;  and  that  its  whole  powers  will  be 
paralysed  for  some  days,  by  exposure  for  a  few  hours  to  a  freezing 
temperature. 

I  have  had  very  frequent  opportunities  of  observing  a  remarkable 
power  in  trees,  of  transferring  their  sap  from  one  tube  to  another  ;  for  I 
have  often  intersected,  in  the  trunk,  every  tube  which  led  to  a  lateral 
branch,  and  still  this  branch  has  derived  a  considerable  portion  of 
nourishment  from  the  trunk.  And  if  the  tubes  of  an  annual  shoot  of 
the  oak  be  traced  downwards  in  the  autumn,  they  will  be  found  to  pass 
along  the  layer  of  wood  of  the  preceding  summer,  without  any  apparent 
communication  between  them  and  the  tubes  of  any  former  year's  growth. 
Yet  the  sap  rises  through  the  whole  of  the  white  wood  ;  and  it  must  be 


94  ACCOUNT^  OF    SOME    EXPERIMENTS    ON    THE 

transferred  from  the  internal  tubes  to  those  near  the  surface,  which  alone 
appear  to  communicate  with  the  central  tubes  of  the  young  shoots  and 
leaves.  Indeed,  we  have  frequent  evidence  that  trees  possess  this  power; 
for  we  see  that  the  whole  sap  of  the  stock  is  carried  into  an  inserted  bud 
or  graft. 

I  at  one  time  suspected  that  a  small  portion  of  sap,  in  its  descent  from 
the  leaves,  had  been  carried  down  by  the  wood,  through  my  incisions, 
in  the  preceding  experiments  on  the  crab-tree,  because  1  observed  a  very 
small  increase  in  size,  in  the  lower  part  of  the  stocks  ;  which,  I  think, 
could  not  have  taken  place  without  some  matter  derived  from  the  leaves. 
But  subsequent  observation  induces  me  to  believe,  that  the  small  quantity 
of  additional  matter  found  in  the  lower  part  of  the  stock  came  from  a 
different  source.  In  those  experiments  I  paid  little  attention  to  any 
small  shoots  which  sprang  from  the  trunk  at  some  distance  below  the 
incisions ;  and  the  buds,  which  usually  began  to  vegetate  about  mid- 
summer, were  not  always  rubbed  off  till  some  minute  leaves  appeared. 
Through  these  I  now  believe  that  a  small  quantity  of  sap  was  thrown 
into  the  bark,  and  carried  up  through  its  tubes  by  capillary  attraction, 
when  the  current  from  above  was  intercepted  ;  for  the  increase  of  size 
in  the  stock  always  diminished,  as  it  ascended  towards  the  incision ; 
which,  I  think,  would  not  have  been  the  case,  had  it  been  produced  by 
nourishment  descending  from  the  upper  parts  of  the  tree. 

Nothing  has  occurred  in  the  preceding  experiments  to  throw  much 
light  on  the  office  of  the  medulla,  to  which  Linnseus  and  subsequent 
writers  have  annexed  so  much  importance ;  but  I  will  now  endeavour  to 
point  out  one  of  its  offices.  In  the  young  and  succulent  shoot  this 
substance  is  extremely  full  of  moisture ;  and,  as  there  is  an  immediate 
communication  bet\veen  it  and  the  leaf,  through  the  central  tubes,  I 
conclude  it  forms  a  reservoir,  to  supply  the  leaf  with  moisture,  whenever 
an  excess  of  perspiration  puts  that  in  a  state  to  require  it.  Some  reser- 
voir of  this  kind  appears  to  me  to  be  necessary  to  plants,  for  their  young 
leaves  are  excessively  tender,  and  they  perspire  much ;  and  cannot,  like 
animals,  fly  to  the  shade  and  the  brook.  In  the  mature  annual  branches, 
and  in  those  of  more  than  one  year  old,  the  medulla  is  dry,  and,  I  think, 
it  is  evidently  lifeless ;  but  the  space  it  occupies  is  never  filled  with  wood, 
as  some  naturalists  have  imagined. 

The  heart  or  coloured  wood,  distinguished  from  the  alburnum,  seems 
to  execute  an  office  somewhat  similar  to  the  bone  in  the  animal  economy. 
The  rigid  texture  of  the  vegetable  fibre,  has  rendered  this  substance 
unnecessary  in  the  young  subject ;  but,  as  the  powers  of  destruction, 


ASCENT    OF    THE    SAP    IN    TREES.  95 

both  from  winds  and  gravity,  increase  in  a  compound  ratio  with  the 
growth  of  the  tree,  some  stronger  substance  than  the  alburnum  may 
be  supposed  to  be  wanting  to  support  the  additional  weight  of  fruit 
and  seeds.  In  the  root  this  substance  cannot  be  wanted,  and  there 
it  is  not  found ;  but  if  the  mould  be  taken  away  from  the  roots  round 
the  trunk,  so  that  they  are  exposed  to  the  air,  and  made  to  support  the 
weight  of  the  tree,  they  become  as  full  of  coloured  wood  as  the  trunk 
and  large  branches.  Having  cut  through  the  alburnum  of  an  oak 
all  round,  not  the  slightest  mark  of  vegetation  appeared  in  the  succeed- 
ing spring ;  and,  having  been  unable  to  impel  either  air  or  water  through 
its  tubes,  I  conclude  that  the  coloured  wood  of  the  oak  is  without 
circulation: — I  see  very  little  reason,  however,  to  admit  that  it  is  with- 
out life  in  a  young  or  middle-aged  tree.  The  new  matter  which  enters 
into  the  internal  part  of  the  alburnum,  on  its  conversion  into  heart 
or  coloured  wood,  seems  to  be  of  a  nature  different  from  the  alburnum 
itself;  for  it  not  only  changes  its  colour,  which  is  nearly  white,  to  a  dark 
brown,  but  it  renders  it  at  least  ten  times  more  durable.  Some  portion 
of  this  increased  durability  may,  perhaps,  be  attributable  to  the  superior 
solidity  of  the  coloured  wood;  but  a  little  attention  to  the  common 
kinds  of  English  timber,  (omitting  the  resinous  tribe,)  will  convince 
us  that  these  qualities,  though  frequently  found  together,  have  very  little 
connexion  with  each  other.  If  a  number  of  oaks  of  the  same  age  be 
examined,  it  will  be  found  that,  in  some  individuals,  the  alburnum 
consists  of  a  greater  number  of  annual  layers  than  in  others,  and  that 
the  coloured  wood  will  have  approached  nearer  the  bark  on  one  side 
than  on  the  other,  in  the  same  tree  ;  the  termination  also  of  the  coloured 
wood,  and  the  commencement  of  the  alburnum,  are  often  found  in  the 
middle  of  an  annual  layer  of  wood ;  and  each  substance,  at  the  points 
of  contact,  possesses  all  its  characteristic  properties.  The  alburnum, 
I  think,  evidently  extends  itself  laterally,  without  any  radicles  descend- 
ing from  the  leaves  or  buds  above.  I  have  often  procured  a  union, 
by  grafting,  between  trees  of  different  kinds,  and  have  sometimes  found 
mere  varieties  of  the  same  species  of  tree,  whose  wood  was  sufficiently 
distinguishable,  in  every  stage  of  future  growth,  to  allow  me  readily 
to  trace  their  line  of  union.  The  wood  of  the  graft  does  not  at  all 
descend  below  its  original  place  of  junction  with  that  of  the  stock  ; 
which,  immediately  below,  wholly  retains  its  native  character;  and, 
in  the  part  where  both  are  spliced  together,  each  constantly  extends 
itself  in  the  direction  of  the  divergent  laminae  of  its  silver  grain.  The 
heart  wood  also  appears  to  increase  by  lateral  extension ;  but  I  am 


96  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

ignorant  of  the  channels  through  which  the  additional  matter  is  con- 
veyed to  it. 

I  will  now  take  the  liberty  of  stating  a  few  of  the  conclusions  that  I 
have  ventured  to  draw  from  the  foregoing,  and  many  similar  experi- 
ments. As  I  have  not  been  able  to  find  the  spiral  tubes  anywhere, 
except  immediately  surrounding  the  medulla  in  different  parts,  in  the 
seed,  and  in  the  leaf,  and  as  they  everywhere  terminate  at  short 
distances,  I  conclude  that  the  sap  is  not  raised  by  their  agency ; 
nor  by  the  central  vessels,  to  which  they  are  appendages :  for  these 
extend  no  greater  length  downwards  than  the  spiral  tubes,  and  ter- 
minate with  them  at  the  external  surface  of  that  annual  layer  of 
wood  to  which  they  belong ;  and  they  have  not  any  apparent  communi- 
cation with  the  similar  vessels  of  the  succeeding  year.  In  the  lower 
parts  of  hollow  trees  they  must  long  have  ceased  to  exist  at  all :  and,  in 
all  trees,  except  very  young  ones,  they  are  (as  it  were)  ossified  within 
the  heart  wood ;  and  those  in  the  annual  shoots  and  buds  are  often  a 
hundred- and- fifty  feet  distant  from  the  roots,  from  which  they  are  sup- 
posed to  raise  the  sap. 

The  common  tubes  of  the  alburnum,  (which  do  not  appear  to  me  to 
have  been  properly  distinguished  from  the  central  vessels  by  the  authors 
that  I  have  read,)  extend  from  the  points  of  the  annual  shoots  to  the  extre- 
mities of  the  roots ;  and  up  these  tubes  the  sap  most  certainly  ascends, 
impelled,  I  believe,  by  the  agency  of  the  silver  grain.  At  the  base  of  the 
buds,  and  in  the  soft  and  succulent  part  of  the  annual  shoot,  the  albur- 
num, with  the  silver  grain,  ceases  to  act  and  to  exist ;  and  here,  I  believe, 
commences  the  action  of  the  central  vessels,  with  their  appendages,  the 
spiral  tubes.  By  these  the  sap  is  carried  into  the  leaves,  and  exposed  to 
the  air  and  light ;  and  here  it  seems  to  acquire  (by  what  means  I  shall 
not  attempt  to  decide)  the  power  to  generate  the  various  inflammable 
substances  that  are  found  in  the  plant.  It  appears  to  be  then  brought 
back  again,  through  the  vessels  of  the  leaf  stalk,  to  the  bark,  and  by  that 
to  be  conveyed  to  every  part  of  the  tree,  to  add  new  matter,  and  to  com- 
pose its  various  organs  for  the  succeeding  season.  When  I  have  inten- 
tionally shaded  the  leaves,  I  have  found  that  the  quantity  of  alburnum 
deposited  has  been  extremely  small. 

In  speaking  of  the  circulation  within  the  apple  and  pear,  I  wish  to 
express  myself  with  much  less  decision,  as  I  have  not  seen  the  effects  of 
taking  up  any  of  those  vessels  into  which  the  coloured  infusions  did  not 
enter.  The  internal  organization  of  the  leaf,  and  of  the  wood,  of  those 
trees  which  have  a  central  medulla,  seems  to  admit  but  of  little  variation, 


ASCENT    OF    THE    SAP    IX    TREES. 


97 


and  (as  far  as  I  have  had  opportunities  to  examine)  of  no  essential 
difference;  whilst  that  of  different  fruits  is  extremely  various.  The 
external  vascular  parts  of  the  apple  and  pear,  abstracted  from  those 
which  seem  to  carry  nourishment  to  the  seeds,  appear  to  me  to  resemble, 
in  some  respects,  those  of  the  leaf;  and,  relative  to  the  offspring,  I 
suspect  that  they  perform  a  somewhat  similar  office. 


III.— ACCOUNT  OF  SOME    EXPERIMENTS   ON  THE    DESCENT   OF  THE  SAP 

IN  TREES, 

[Read  before  the  ROYAL  SOCIETY,  April  21,  1803.] 

IN  a  memoir  which  I  had  the  honour  to  present  two  years  ago*,  I 
related  some  experiments  on  trees,  from  which  I  inferred,  that  their  sap, 
having  been  absorbed  by  the  bark  of  the  root,  is  carried  up  by  the  albur- 
num, or  \vhite  wood  of  the  root,  the  trunk,  and  the  branches ;  that  it 
passes  through  what  are  there  called  central  vessels,  into  the  succulent 
part  of  the  annual  shoot,  the  leaf-stalk,  and  the  leaf ;  and  that  it  returns 
to  the  bark,  through  the  returning  vessels  of  the  leaf-stalk.  The  prin- 
cipal object  of  this  paper  is  to  point  out  the  causes  of  the  descent  of  the 
sap  through  the  bark,  and  the  consequent  formation  of  wood. 

These  causes  appear  to  be  gravitation,  motion  communicated  by 
winds  or  other  agents,  capillary  attraction,  and  probably  something  in 
the  conformation  of  the  vessels  themselves,  which  renders  them  better 
calculated  to  carry  fluids  in  one  direction  than  in  another.  I  shall 
begin  with  a  few  observations  on  the  leaf,  from  which  all  the  descend- 
ing fluids  in  the  tree  appear  to  be  derived.  This  organ  has  much 
engaged  the  attention  of  naturalists,  particularly  of  M.  Bonnet:  but 
their  experiments  have  chiefly  been  made  on  leaves  severed  from  the 
tree ;  and,  therefore,  whatever  conclusions  have  been  drawn  stand  on 
very  questionable  ground.  The  efforts  which  plants  always  make  to 
turn  the  upper  surfaces  of  their  leaves  to  the  light,  have  with  reason 
induced  naturalists  to  conclude,  that  each  surface  has  a  totally  distinct 
office  ;  and  the  following  experiments  tend  strongly  to  support  that 
conclusion. 

I  placed  a  small  piece  of  plate  glass  under  a  large  vine  leaf,  with 
its  surface  nearly  parallel  with  that  of  the  leaf ;  and,  as  soon  as  the  glass 
had  acquired  the  temperature  of  the  house  in  which  the  vine  grew, 

*  See  the  preceding  paper. 


98  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

I  brought  the  under  surface  of  the  leaf  into  contact  with  it,  by  means  of 
a  silk  thread  and  a  small  wire  adapted  to  its  form  and  size.  Having 
retained  the  leaf  in  this  position  one  minute,  T  removed  it,  and  found  the 
surface  of  the  glass  covered  with  a  strong  dew,  which  had  evidently 
exhaled  from  the  leaf.  I  again  brought  the  leaf  into  contact  with  the 
glass,  and,  at  the  end  of  half  an  hour,  found  so  much  water  discharged 
from  the  leaf,  that  it  ran  off  the  glass  when  held  obliquely. 

I  then  inverted  the  position  of  the  leaf,  and  placed  its  upper  surface 
in  contact  with  the  glass :  not  the  slightest  portion  of  moisture  now 
appeared,  though  the  leaf  was  exposed  to  the  full  influence  of  the  meridian 
sun.  These  experiments  were  repeated  on  many  different  leaves  ;  and, 
the  result  was,  in  every  instance,  precisely  the  same.  It  seems,  there- 
fore, that,  in  the  vine,  the  perspiratory  vessels  are  confined  to  the  under 
surface  of  the  leaf ;  and  these,  like  the  cutaneous  lymphatics  of  the 
animal  economy,  are  probably  capable  of  absorbing  moisture,  when  the  plant 
is  in  a  state  to  require  it.  The  upper  surface  seems,  from  the  position  it 
always  assumes,  either  formed  to  absorb  light,  or  to  operate  by  the  influ- 
ence of  that  body  :  and  if  any  thing  exhale  from  it,  it  is  probably  vital  air, 
or  some  other  permanently  elastic  fluid.  It  nevertheless  appears  evident, 
in  the  experiments  of  Bonnet,  that  this  surface  of  the  leaves  of  many 
plants,  when  detached  from  the  tree,  readily  absorbs  moisture. 

Selecting  two  young  shoots  of  the  vine,  growing  perpendicularly 
against  the  back  wall  of  my  vinery,  I  bent  them  downwards,  nearly 
in  a  perpendicular  line,  and  introduced  their  succulent  ends,  as  layers, 
into  two  pots,  without  wounding  the  stems,  or  depriving  them  of  any 
portion  of  their  leaves.  In  this  position,  these  shoots,  which  were  about 
four  feet  long,  and  sprang  out  of  the  principal  stem,  about  three  feet 
from  the  ground,  grew  freely,  and  in  the  course  of  the  summer  reached 
the  top  of  the  house.  A  s  soon  as  their  wood  became  sufficiently  solid 
to  allow  me  to  perform  the  operation  with  safety,  I  made  two  circular 
incisions  through  the  bark  of  the  depending  part  of  each  shoot,  at  a 
small  distance  from  each  other,  near  the  surface  of  the  mould  in  the 
pots,  and  I  wholly  removed  the  bark  between  the  incisions  ;  thus  cutting 
off  all  communication  through  the  bark  between  the  layers  and  the 
parent  stems.  Had  the  subjects  of  this  experiment  now  retained  their 
natural  position,  much  new  wood  and  bark  would  have  been  formed  at 
the  upper  lip  of  the  wounds,  and  none  at  all  at  the  lower,  as  I  have 
ascertained  by  frequent  experiment.  The  case  was  now  different :  much 
new  bark  and  wood  was  generated  on  the  lower  lip  of  the  wounds, 
because  uppermost  by  the  inverted  position  of  the  branches ;  and  I  have 


DESCENT    OF    THE    SAP    IN    TREES.  99 

no  doubt,  but  that  the  new  matter  thus  deposited  owed  its  formation 
to  a  portion  of  sap  which  descended  by  gravitation  from  the  leaves 
growing  between  the  wounded  parts  and  the  principal  stems. 

The  result  of  this  experiment  appears  to  point  out  one  of  the  causes 
why  perpendicular  shoots  grow  with  much  greater  vigour  than  others ; 
they  have  probably  a  more  perfect  and  more  rapid  circulation. 

The  effects  of  motion  on  the  circulation  of  the  sap,  and  the  consequent 
formation  of  wood,  I  was  able  to  ascertain  by  the  following  expedient. 
Early  in  the  spring  of  1801  I  selected  a  number  of  young  seedling 
apple-trees,  whose  stems  were  about  an  inch  in  diameter,  and  whose 
height,  between  the  roots  and  first  branches,  was  between  six  and  seven 
feet.  These  trees  stood  about  eight  feet  from  each  other ;  and.  of 
course,  a  free  passage  for  the  wind  to  act  on  each  tree  was  afforded.  By 
means  of  stakes  and  bandages  of  hay,  not  so  tightly  bound  as  to  impede 
the  progress  of  any  fluid  within  the  trees,  I  nearly  deprived  the  roots 
and  lower  parts  of  the  stems  of  several  trees  of  all  motion,  to  the  height 
of  three  feet  from  the  ground,  leaving  the  upper  parts  of  the  stems  and 
branches  in  their  natural  state.  In  the  succeeding  summer,  much  new 
wood  accumulated  in  the  parts  which  were  kept  in  motion  by  the  wind ; 
but  the  lower  parts  of  the  stems  and  roots  increased  very  little  in  size. 
Removing  the  bandages  from  one  of  these  trees  in  the  following  winter, 
I  fixed  a  stake  in  the  ground,  about  ten  feet  distant  from  the  tree,  on 
the  east  side  of  it ;  and  I  attached  the  tree  to  the  stake,  at  the  height 
of  six  feet,  by  means  of  a  slender  pole  about  twelve  feet  long ;  thus 
leaving  the  tree  at  liberty  to  move  towards  the  north  and  south,  or  more 
properly,  in  the  segment  of  a  circle  of  which  the  pole  formed  a  radius ; 
but  in  no  other  direction.  Thus  circumstanced,  the  diameter  of  the 
tree  from  north  to  south,  in  that  part  of  its  stem  which  was  most 
exercised  by  the  wind,  exceeded  that  in  the  opposite  direction  in  the 
following  autumn,  in  the  proportion  of  thirteen  to  e  even. 

These  results  appear  to  open  an  extensive  and  interesting  field  to  our 
observation,  where  we  shall  find  much  to  admire,  in  the  means  which 
nature  employs  to  adapt  the  forms  of  its  vegetable  productions  to  every 
situation  in  which  art  or  accident  may  deposit  them.  If  a  tree  be  placed 
in  a  high  and  exposed  situation,  where  it  is  much  kept  in  motion  by 
winds,  the  new  matter  which  it  generates  will  be  deposited  chiefly  in  the 
roots  and  lower  parts  of  the  trunk ;  and  the  diameter  of  the  latter  will 
diminish  rapidly  in  its  ascent.  The  progress  of  the  ascending  sap  will 
of  course  be  impeded ;  and  it  will  thence  cause  lateral  branches  to 
be  produced,  or  will  pass  into  those  already  existing.  The  forms  of 


100  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

such  branches  will  be  similar  to  that  of  the  trunk  ;  and  the  growth  of 
the  insulated  tree  on  the  mountain  will  be,  as  we  always  find  it,  low  and 
sturdy,  and  well  calculated  to  resist  the  heavy  gales  to  which  its  situation 
constantly  exposes  it. 

Let  another  tree  of  the  same  kind  be  surrounded,  whilst  young,  by 
others,  and  it  will  assume  a  very  different  form.  It  will  now  be  deprived 
of  a  part  of  its  motion,  and  another  cause  will  operate : — the  leaves 
on  the  lateral  branches  will  be  partly  deprived  of  light,  and,  as  I  have 
remarked  in  the  last  paper  I  had  the  honour  to  address  to  you,  little 
alburnum  will  then  be  generated  in  those  branches.  Their  vigour,  of 
course,  becomes  impaired,  and  less  sap  is  required  to  support  their 
diminished  growth;  more,  in  consequence,  remains  for  the  leading 
shoots ;  these,  therefore,  exert  themselves  with  increased  energy ;  and 
the  trees  seem  to  vie  with  each  other  for  superiority,  as  if  endued  with 
all  the  passions  and  propensities  of  animal  life. 

An  insulated  tree  in  a  sheltered  valley  will  assume,  from  the  fore- 
going causes,  a  form  distinct  from  either  of  the  preceding* ;  arid  its 
growth  will  be  more  or  less  aspiring,  in  proportion  to  the  degree  of  pro- 
tection it  receives  from  winds,  and  its  contiguity  to  elevated  objects,  by 
which  its  lower  branches,  during  any  part  of  the  day,  are  shaded. 

When  a  tree  is  wholly  deprived  of  motion,  by  being  trained  to  a 
wall,  or  when  a  large  tree  has  been  deprived  of  its  branches,  to  be 
regrafted,  it  often  becomes  unhealthy,  and  not  unfrequently  perishes, 
apparently  owing  to  the  stagnation  of  the  descending  sap,  under  the 
rigid  cincture  of  the  lifeless  external  bark.  I  have,  in  the  last  two  years, 
pared  off  this  bark  from  some  very  old  pear  and  apple  trees,  which  had 
been  regrafted  with  cuttings  from  young  seedling  trees,  and  the  effect 
produced  has  been  very  extraordinary.  More  new  wood  has  been 
generated  in  the  old  trunks,  within  the  last  two  years,  than  in  the  pre- 
ceding twenty  years ;  and  I  attribute  this  to  the  facility  of  communica- 
tion which  has  been  restored  between  the  leaves  and  the  roots,  through 
the  inner  bark.  I  have  had  frequent  occasion  to  observe,  that  wherever 

*  Not  only  the  "external  form  of  the  tree,  but  the  internal  character  of  the  wood,  will  be 
affected  by  the  situation  in  which  the  tree  grows ;  and  hence,  oak  timber  which  grew  in  crowded 
forests  appears  to  have  been  mistaken,  in  old  buildings,  for  Spanish  chesnut.  But  I  have 
found  the  internal  organization  of  the  oak  and  Spanish  chesnut  to  be  very  essentially  different. 
(See  a  magnified  view  of  each  in  plate  5.) 

The  silver  grain  and  general  character  of  the  oak  and  Spanish  chesnut  are  also  so  extremely 
dissimilar,  that  the  two  kinds  of  wood  can  only  be  mistaken  for  each  other  by  very  careless 
observers.  Many  pieces  of  wood  found  in  the  old  buildings  of  London,  and  supposed  to  be 
Spanish  chesnut,  have  been  put  into  my  hands  ;  but  they  were  all  most  certainly  forest  oak. 


DESCENT    OF    THE    SAP    IN    TREES.  101 

the  bark  has  been  most  reduced,  the  greatest  quantity  of  wood  has  been 
deposited. 

Other  causes  of  the  descent  of  the  sap  towards  the  root  I  have  sup- 
posed to  be  capillary  attraction,  and  something  in  the  conformation  of 
the  vessels  of  the  bark.  The  alburnum  also  appears,  in  my  former 
experiments,  to  expand  and  contract  very  freely  under  changes  of 
temperature  and  of  moisture  ;  and  the  motion  thus  produced  must  be  in 
some  degree  communicated  to  the  bark,  should  the  latter  mb$t%4co.jJbp 
in  itself  wholly  inactive.  I  however  consider  gravitatioii  &s  th&  most- 
extensive  and  active  cause  of  motion  in  the  descending  mrids  or  trees; 
and  I  believe  that,  from  this  agent,  vegetable  bodies,  like  unorganized 
matter,  generally  derive,  in  a  greater  or  less  degree,  the  forms  they 
assume  :  and  probably  it  is  necessary  to  the  existence  of  trees  that  it 
should  be  so.  For  if  the  sap  passed  and  returned  as  freely  in  the 
horizontal  and  pendent,  as  in  the  perpendicular  branch,  the  growth  of 
each  would  be  equally  rapid,  or  nearly  so :  the  horizontal  branch  would 
then  soon  extend  too  far  from  its  point  of  suspension  at  the  trunk  of  the 
tree,  and  would  inevitably  perish,  by  the  increase  in  a  compound  ratio  of 
the  powers  of  destruction,  as  compared  with  those  of  preservation. 

The  principal  office  of  the  horizontal  branch,  in  the  greatest  number 
of  trees,  is  to  nourish  and  support  the  blossoms,  and  the  fruit,  or  seed ; 
and  as  these  give  back  little  or  nothing  to  the  parent  tree,  very  feeble 
powers  alone  are  wanted  in  the  returning  system.  No  power  at  all  had 
been  fatal;  and  power  sufficiently  strong  wholly  to  counteract  the 
effects  of  gravitation  had  probably  been  in  a  high  degree  destructive. 
And  it  appears  to  me  by  no  means  improbable,  that  the  formation  of 
blossoms  may,  in  many  instances,  arise  from  the  diminished  action  of 
the  returning  system  in  the  horizontal  or  pendent  branch. 

I  have  long  been  disposed  to  believe  the  ascending  fluids  in  the  albur- 
num and  central  vessels,  wherever  found,  to  be  everywhere  the  same ; 
and  that  the  leaf-stalk,  the  tendril  of  the  vine,  the  fruit-stalk,  and  the 
succulent  point  of  the  annual  shoot,  might  in  some  measure  be  substituted 
for  each  other ;  and  experiment  has  proved  my  conjecture,  in  many 
instances,  to  be  well  founded.  Leaves  succeeded  and  continued  to  per- 
form their  office  when  grafted  on  the  leaf-stalk;  the  tendril  and  the 
fruit-stalk  alike,  supplied  a  branch  grafted  upon  them  with  nourishment. 
But  I  did  not  succeed  in  grafting  a  fruit -stalk  of  the  vine  on  the  leaf- 
stalk, the  tendril,  or  succulent  shoot.  My  ill  success,  however,  I  here 
attribute  solely  to  want  of  proper  management,  and  I  have  little  doubt 
of  succeeding  in  future. 


102  ACCOUNT    OF    SOME    EXPERIMENTS    ON    THE 

The  young  shoots  of  the  vine,  when  grafted  on  the  leaf-stalk,  often 
grew  to  the  length  of  nine  or  ten  feet ;  and  the  leaf-stalk  itself,  to 
some  distance  below  its  juncture  with  the  graft,  was  found  in  the  autumn 
to  contain  a  considerable  portion  of  wood,  in  every  respect  similar  to 
the  alburnum  in  other  parts  of  the  tree. 

The  formation  of  alburnum  in  the  leaf-stalk  seemed  to  point  out 
to  me  the. means  of  ascertaining  the  manner  in  which  it  is  generated 
in  other,. instances ;  and  to  that  point  my  attention  was  in  consequence 
attracted*  t  Jlaving  grafted  leaf-stalks  with  shoots  of  the  vine,  I  exa- 
mined, hi  tranverse  sections,  the  commencement  and  gradual  formation 
of  the  wood.  It  appeared  evidently  to  spring  from  the  tubes  which, 
in  my  last  paper,  (to  which  I  must  refer  you,)  I  have  called  the  return- 
ing vessels  of  the  leaf-stalk  ;  and  to  be  deposited  on  the  external  sides 
of  what  I  have  there  named  the  central  vessels,  and  on  the  medulla. 
The  latter  substance  appeared  wholly  inactive ;  and  I  could  not  discover 
anything  like  the  processes  supposed  to  extend  from  it  in  all  cases 
into  the  wood. 

The  organization  of  the  young  shoot  is  extremely  similar  to  that  of 
the  leaf-stalk,  previous  to  the  formation  of  wood  within  it.  The  same 
vessels  extend  through  both ;  and  therefore  it  appeared  extremely 
probable,  that  the  wood  in  each  would  be  generated  in  the  same  man- 
ner ;  and  subsequent  observation  soon  removed  all  ground  of  doubt. 

It  is  well  known  that,  in  the  operation  of  budding,  the  bark  of  a  tree, 
being  taken  off,  readily  unites  itself  to  another  of  the  same,  or  of  a 
kindred  species.  An  examination  of  the  manner  in  which  this  union 
takes  place,  promised  some  further  information.  In  the  last  summer, 
therefore,  I  inserted  a  great  number  of  buds,  which  I  subsequently 
examined  in  every  progressive  stage  of  their  union  with  the  stock.  A 
line  of  confused  organization  marks  the  place  where  the  inserted  bud  first 
comes  into  contact  with  the  wood  of  the  stock ;  between  which  line  and 
the  bark  of  the  inserted  bud  new  wood  regularly  organized  is  generated. 
This  wood  possesses  all  the  characteristics  of  that  from  which  the 
bud  was  taken,  without  any  apparent  mixture  whatever  with  the  char- 
acter of  the  stock  in  which  it  is  inserted.  The  substance  which  is 
called  the  medullary  process,  is  clearly  seen  to  spring  from  the  bark, 
and  to  terminate  at  the  line  of  its  first  union  with  the  stock. 

An  examination  of  the  manner  in  which  wounds  in  trees  become 
covered,  (for,  properly  speaking,  they  never  can  be  said  to  heal,)  affords 
further  proof,  were  it  wanted,  that  the  medullary  processes,  (as  they  are 
improperly  named),  like  every  other  part  of  the  wood,  are  generated 
by  the  bark. 


DESCENT  OF  THE    SAP    IN    TREES.  103 

Whenever  the  surface  of  the  alburnum  is  exposed  but  for  a  few  hours 
to  the  air,  though  no  portion  of  it  be  destroyed,  vegetation  on  that 
surface  for  ever  ceases  :  but  new  bark  is  gradually  protruded  from  the 
sides  of  the  wound,  and  by  this,  new  wood  is  generated.  In  this  wood 
the  medullary  processes  are  distinctly  seen  to  take  their  origin  from  the 
bark,  and  to  terminate  on  the  lifeless  surface  of  the  old  wood  within  the 
wound.  These  facts  incontestably  prove,  that  the  medullary  processes, 
which  in  my  former  paper  I  call  the  silver  grain,  do  not  diverge  from  the 
medulla,  but  that  they  are  formed  in  lines  converging  from  the  bark  to 
the  medulla,  and  that  they  have  no  connexion  whatever  with  the  latter 
substance.  And  surely  nothing  but  the  fascinating  love  of  a  favourite 
system,  could  have  induced  any  naturalist  to  believe  the  hardest,  the 
most  solid,  and  most  durable  part  of  the  wood,  to  be  composed  of  the 
soft,  cellular,  and  perishable  substance  of  the  medulla. 

In  my  last  paper,  I  have  supposed  that  the  sap  acquired  the  power  to 
generate  wood  in  the  leaf;  and  I  have  subsequently  found  no  reason  to 
retract  that  opinion.  But  the  experiment  in  which  wood  was  generated 
in  the  leaf-stalk,  apparently  by  the  sap  descended  from  the  bark  of  the 
graft,  induces  me  to  believe  that  the  descending  fluid  undergoes  some 
further  changes  in  the  bark,  possibly  by.  discharging  some  of  its  com- 
ponent parts  through  the  pores  described  and  figured  by  Malpighi. 

I  also  suspected,  since  my  former  paper  was  written,  that  the  young 
bark,  in  common  with  the  leaf,  possessed  a  power,  in  proportion  to  the 
surface  it  exposes  to  the  air  and  light,  of  preparing  the  sap  to  generate 
new  wood  ;  for  I  found  that  a  very  minute  quantity  of  wood  was  deposited 
by  the  bark,  where  it  had  not  any  apparent  connexion  with  the  leaves. 
Having  made  two  incisions  through  the  bark  round  annual  shoots  of  the 
apple-tree,  I  entirely  removed  the  bark  between  the  incisions,  and  I 
repeated  the  same  operation  at  a  little  distance  below,  leaving  a  small 
portion  of  bark  unconnected  with  that  above  and  beneath  it.  By  this 
bark  a  very  minute  quantity  of  wood  in  many  instances  appeared  to  be 
generated  at  its  lower  extremity.  The  buds  in  the  insulated  bark  were 
sometimes  suffered  to  remain,  and  in  other  instances  were  taken  away  ; 
but  these,  unless  they  vegetated,  did  not  at  all  affect  the  result  of  the 
experiment.  I  could  therefore  account  for  the  formation  of  wood  in  this 
case,  only  by  supposing  the  bark  to  possess  in  some  degree,  in  common 
with  the  leaf,  the  power  to  produce  the  necessary  changes  in  the  descend- 
ing sap  ;  or,  that  some  matter,  originally  derived  from  the  leaves,  was 
previously  deposited  in  the  bark ;  or  that  a  portion  of  sap  had  passed 
the  narrow  space  above,  from  which  the  bark  had  been  removed,  through 


104  EXPERIMENTS  ON  THE  DESCENT  OF  THE  SAP. 

the  wood  Repeating  the  experiment,  I  left  a  much  greater  length  of 
bark  between  the  intersections ;  but  no  more  wood  than  in  the  former 
instance  was  generated.  I  therefore  concluded  that  a  small  quantity 
of  sap  must  have  found  its  way  through  the  wood  from  the  leaves  above; 
and  I  found  that  when  the  upper  incisions  were  made  at  ten  or  twelve 
lines  distance,  instead  of  one  or  two,  and  the  bark  between  them, 
as  in  former  experiments,  was  removed,  no  wood  was  generated  by  the 
insulated  bark. 

I  shall  conclude  my  paper  with  a  few  remarks  on  the  formation  of 
buds  in  tuberous-rooted  plants,  beneath  the  ground.  They  must,  if  my 
theory  be  well  founded,  be  formed  of  matter  which  has  descended  from 
the  leaves  through  the  bark.  I  shall  confine  my  observations  to  the 
potato.  Having  raised  some  plants  of  this  kind  in  a  situation  well 
adapted  to  my  purpose,  I  waited  till  the  tubers  were  about  half  grown  ; 
and  I  then  commenced  my  experiment,  by  carefully  intersecting  with  a 
sharp  knife  the  runners  which  connect  the  tubers  with  the  parent  plant, 
and  immersing  each  end  of  the  runners  thus  intersected  in  a  decoction 
of  logwood.  At  the  end  of  twenty-four  hours  I  examined  the  state 
of  the  experiment;  and  I  found  that  the  decoction  had  passed  along 
the  runners  in  each  direction ;  but  I  could  not  discover  that  it  had 
entered  into  any  of  the  vessels  of  the  parent  plant.  This  result  I  had 
anticipated ;  because  I  concluded  that  the  matter  by  which  the  growing 
tuber  is  fed  must  descend  from  the  leaves  through  the  bark  ;  and 
experience  had  long  before  taught  me  that  the  bark  would  not  absorb 
coloured  infusions.  I  now  endeavoured  to  trace  the  progress  of  the 
infusion  in  the  opposite  direction,  and  my  success  here  much  exceeded 
my  hopes. 

A  section  of  potato  presents  four  distinct  substances ;  the  internal 
part,  which,  from  the  mode  of  its  formation  and  subsequent  office,  I  con- 
ceive allied  to  the  alburnum  of  ligneous  plants ;  the  bark  which  surrounds 
this  substance ;  the  true  skin  of  the  plant ;  and  the  epidermis.  Making 
transverse  sections  of  the  tubers  which  had  been  the  subjects  of  experi- 
ments, I  found  that  the  coloured  infusion  had  passed  through  an  elabo- 
rate series  of  vessels  between  the  cortical  and  alburnous  substances, 
and  that  many  minute  ramifications  of  these  vessels  approached  the 
external  skin  at  the  base  of  the  buds,  to  which,  as  to  every  other  part 
of  the  growing  tuber,  I  conclude  they  convey  nourishment. 


105 


IV.— EXPERIMENTS   AND   OBSERVATIONS    ON   THE    MOTION    OF  THE  SAP 

IN  TREES. 

[Read  before  the  ROYAL  SOCIETY,  February  16,  1804.] 

IN  the  Observations  on  the  Descent  of  the  Sap  in  Trees,  which  I  last 
year  took  the  liberty  to  lay  before  the  Royal  Society,  I  offered  a  con- 
jecture, that  the  vessels  of  the  bark,  which  pass  from  the  leaves  to  the 
extremities  of  the  roots,  were,  in  their  organization,  better  calculated  to 
carry  the  fluids  they  contain  towards  the  roots  than  in  the  opposite 
direction.  I  had  not,  however,  at  that  time,  any  experiment  directly  to 
support  this  supposition ;  but  I  thought  the  forms  generally  assumed  by 
trees  in  their  growth,  evinced  the  compound  and  contending  actions  of 
gravitation,  and  of  an  intrinsic  power  in  the  vessels  of  the  bark,  to  give 
motion  to  the  fluid  passing  through  them.  In  the  account  of  the  experi- 
ments which  I  have  now  the  honour  to  address  to  you,  I  trust  I  shall  be 
able  to  adduce  some  interesting  facts  in  support  of  that  inference. 

Having  selected,  in  the  spring  of  1802,  four  strong  shoots  of  the  vine, 
growing  along  the  horizontal  trellis  of  my  vinery,  I  depressed  a  part  of 
each  shoot,  whilst  it  was  soft  and  succulent,  about  three  inches  deep, 
into  the  mould  of  a  pot  placed  beneath  it  for  that  purpose ;  but  without 
making  any  wound,  or  incision,  in  the  young  shoots  thus  employed  as 
layers. 

In  this  position  they  remained  during  the  succeeding  summer ;  and,  in 
the  autumn,  had  nearly  filled  the  pots,  which  were  ten  inches  in  dia- 
meter, with  their  roots.  As  soon  as  the  leaves  had  fallen,  the  layers 
were  disengaged  from  the  parent  stocks ;  and  about  five  inches  of  wood, 
containing  one  bud,  were  left,  both  at  the  proper  and  the  inverted  end 
of  each  layer.  Every  bud  was  also,  by  previous  management,  made  to 
stand  at  an  equal  distance  from  the  mould  in  the  pots,  and  with  an  equal 
elevation,  of  about  thirty-six  degrees.  About  one  inch  of  wood  was 
likewise  left  at  each  end  of  every  layer,  beyond  the  buds. 

In  the  succeeding  spring,  the  buds  vegetated  strongly,  both  at  the 
proper  and  at  the  inverted  ends  of  the  layers,  as  the  experiments  of 
Hales  and  Duhamel  had  given  me  reason  to  expect  ;  and  in  one 
instance,  the  bud  at  the  inverted  end  of  the  layer  grew  with  greater 
vigour  than  that  at  its  proper  end  :  but  the  growth  of  these  buds  was 
not  the  object  which  I  had  in  view, 

I  have  already  stated,  that  nearly  an  inch  of  wood  was  left  at  each 
end  of  every  layer,  beyond  the  bud ;  and  to  this  wood,  at  the  inverted 
ends  of  the  layers,  my  attention  was  chiefly  directed  :  for  if  the  vessels 


106  EXPERIMENTS    AND    OBSERVATIONS    ON    THE 

of  the  bark  possessed  the  powers  I  attributed  to  them,  I  concluded  that 
the  sap  would  be  impelled  to  the  inverted  ends  of  the  layers,  and  be 
there  employed  in  the  production  of  new  wood  and  roots  ;  and  in  this 
my  expectations  were  not  disappointed.  At  the  proper  end  of  the  layers, 
the  wood  immediately  beyond  the  buds  became  dry  and  lifeless  early  in 
the  succeeding  summer  ;  the  stems  also,  between  the  buds  and  the 
mould  in  the  pots,  increased  in  size  as  usual ;  and  nothing  peculiar 
occurred.  But  at  the  inverted  end  appearances  were  extremely  dif- 
ferent :  new  wood  here  accumulated  rapidly  beyond  the  buds,  and 
numerous  roots,  of  considerable  length,  were  emitted,  whilst  no  sensible 
growth  took  place  between  the  base  of  the  young  shoots  and  the  mould 
in  the  pots. 

It  having  been  proved  by  Duhamel  that  inverted  parts  of  trees 
readily  emit  roots,  I  expected  to  derive  further  information  from  cuttings 
of  this  kind  :  I  therefore  planted,  in  the  autumn  of  1802,  forty  cuttings 
of  the  gooseberry-tree,  and  an  equal  number  of  the  common  currant- 
tree  ;  one  half  of  each  being  inverted.  Of  the  former,  not  one  of  the 
inverted  cuttings  succeeded ;  whereas  few  of  the  latter  failed  ;  and  in 
these  I  had  an  opportunity  of  observing  the  same  accumulation  of  wood 
above  the  bases  of  the  annual  shoots,  and  the  same  mode  of  growth,  in 
every  respect,  as  in  the  inverted  vines  ;  except  that  no  roots  were 
emitted  at  their  upper  ends.  The  same  thing  occurred,  without  any 
variation,  in  inverted  grafts  of  the  apple-tree. 

If  it  be  admitted,  according  to  the  theory  I  have  on  a  former  occasion 
laid  before  you,  that  the  sap  descends  from  the  leaves  through  the  vessels 
of  the  bark ;  and  that  such  vessels  are,  in  their  organisation,  better  calcu- 
lated to  carry  their  contents  towards  the  original  roots  than  in  the 
opposite  direction ;  it  will  be  extremely  easy  to  explain  the  cause  of  the 
accumulation  of  wood,  and  the  emission  of  roots,  above,  instead  of  below, 
the  base  of  the  annual  shoots.  The  vessels  of  the  bark  (the  vaisseaux 
propres  of  Duhamel)  commencing  in  the  leaves,  were  formerly  traced 
by  M.  Mariotte,  and  subsequently  by  myself,  (being  ignorant  of  his 
discovery,)  to  the  extremities  of  the  roots ;  and  when  a  cutting,  or  tree, 
is  planted  in  its  natural  position,  the  sap  passes  downwards  through  these 
to  afford  matter  for  new  roots,  and  to  increase  the  bulk  of  those  already 
formed,  having  given  proper  nutriment  to  the  branches  and  trunk  in  its 
descent.  But,  in  the  inverted  cutting,  or  tree,  these  vessels  become 
inverted;  and,  if  their  organisation  be  such  as  I  have  supposed  it,  a 
considerable  part  of  -that  fluid,  which  naturally  descends,  will  be  carried 
upwards,  and  occasion  the  production  of  new  wood,  above,  instead  of 


MOTION    OF    THE    SAP    IN    TREES.  107 

below,  the  junction  of  the  annual  shoot  with  the  older  wood,  as  in  the 
experiments  I  have  described.  The  force  of  gravitation  will,  however, 
still  be  felt ;  and,  by  its  agency,  sufficient  matter  to  form  new  roots  may 
be  conveyed  to  those  parts  of  the  inverted  cutting,  or  tree,  which  are 
beneath  the  soil.  Besides,  if  we  suppose  a  variation  to  exist  in  the 
powers  or  organisation  of  the  vessels  which  carry  the  sap  towards  the 
root,  we  may  also  attribute,  in  a  great  measure,  to  this  cause,  the 
different  forms  which  different  species  or  varieties  of  trees  assume  ;  for, 
if  the  fluid  in  these  vessels  be  impelled  with  much  force  towards  the 
roots,  little  matter  will  probably  be  deposited  in  the  branches  ;  which, 
in  consequence,  will  be  slender  and  feeble,  as  in  the  vine ;  and  there  is 
not  any  tree  that  has  been  the  subject  of  my  experiments,  in  which  new 
wood  accumulated  so  rapidly  at  the  upper  end  of  inverted  plants.  To 
an  excess  of  this  power,  in  the  vessels  of  the  bark,  we  may  also  ascribe 
the  peculiar  growth  of  what  are  called  weeping  trees  ;  for,  by  this  power, 
the  effects  of  gravitation  will  be,  in  a  great  degree,  suspended  ;  and  the 
pendent  branch  will  continue  healthy  and  vigorous,  by  retaining  its  due 
circulation.  The  perpendicular  branch  will,  however,  still  possess  some 
advantages ;  for,  in  this,  gravitation  will  act  on  the  fluid  descending  from 
the  leaves ;  and  these  will,  of  course,  absorb  from  the  atmosphere  with 
increased  activity.  A  greater  quantity  of  matter  will  therefore  enter, 
within  any  given  portion  of  time,  into  vessels  of  the  same  capacity ;  and 
this  increased  quantity  may  frequently  exceed  that  which  the  vessels  of 
the  bark  are  immediately  prepared  to  carry  away.  Much  new  wood  will 
in  consequence  be  generated,  and  increased  vigour  given ;  and,  the  same 
causes  operating  through  successive  seasons,  will  give  the  ascendancy  we 
generally  observe  in  the  perpendicular  branch. 

In  the  preceding  experiments  none  of  the  layers,  or  cuttings,  exceeded 
a  few  inches  in  length  ;  and,  to  the  summit  of  these  the  sap  appeared  to 
rise,  through  the  inverted  tubes  of  the  wood,  nearly  as  well  as  in  those 
which  retained  their  natural  position.  But  some  further  experiments 
had  induced  me  to  suspect  that  this  would  not  be  the  case  in  longer 
cuttings ;  I  therefore  planted,  in  the  autumn  of  1802,  twelve  cuttings  of 
the  sallow,  (Salix  caprea.)  inverting  one-half  of  them.  The  whole  readily 
emitted  roots,  and  grew  with  luxuriance ;  but  their  modes  of  growth 
were  extremely  different.  In  the  cuttings  which  stood  in  their  natural 
position,  vegetation  proceeded  with  most  vigour  at  the  points  most 
elevated ;  but,  in  the  inverted  cuttings,  it  grew  more  and  more  languid 
as  it  became  distant  from  the  ground,  and  nearly  ceased,  towards  the 
conclusion  of  the  summer,  at  the  height  of  four  feet.  The  new  wood 


108  EXPERIMENTS    AND    OBSERVATIONS    ON    THE 

also,  which  was  generated  by  these  inverted  cuttings,  accumulated  above 
the  bases  of  the  annual  shoots,  as  in  the  preceding  instances. 

These  facts  appear  to  prove,  that  the  vessels  of  plants  are  not  equally 
well  calculated  to  carry  their  contents  in  opposite  directions  ;  and,  I 
think,  afford  some  grounds  to  suspect  that  the  vessels  of  the  bark,  like 
those  which  constitute  the  venous  system  of  animals,  (to  which  they  are 
in  many  respects  analogous,)  may  be  provided  with  valves,  whose  extreme 
minuteness  has  concealed  them  from  observation. 

The  experiments,  and  still  more  the  plates,  of  Hales,  have  induced 
naturalists  to  draw  conclusions  in  direct  opposition  to  the  preceding. 
But  the  plates  of  that  great  naturalist  are  not  always  taken  correctly 
from  nature  * ;  and  plates,  under  such  circumstances,  however  fair  and 
candid  the  intentions  of  an  author  may  be,  will  too  often  be  found  some- 
what better  calculated  to  support  his  own  hypothesis  than  to  elucidate 
the  facts  he  intends  to  state. 

The  preceding  peculiarities  in  the  growth  of  inverted  cuttings,  appear 
to  have  escaped  the  observation  of  Duhamel ;  and,  as  very  few  instances 
of  error,  or  want  of  accurate  observation,  will  ever  be  found  in  the  works 
of  that  excellent  naturalist,  I  must  request  permission  to  send  you  some 
of  the  subjects  of  my  experiments,  as  vouchers  for  my  own  accuracy. 

Of  the  inverted  cuttings  employed  by  Duhamel,  a  small  portion  only 
appears  to  have  remained  above  the  ground ;  and,  under  such  circum- 
stances, the  different  forms  of  those  growing  in  their  natural,  or  inverted, 
position  would  be  scarcely  observable.  It  appears  also,  from  his  experi- 
ments, that  such  inverted  cuttings,  in  subsequent  years,  grow  with  as 
much  vigour  as  others  that  are  not  inverted ;  whence  we  must  conclude 
that  the  organisation  of  the  internal  bark  becomes  again  inverted,  and 
adapted  to  the  position  of  the  branch.  The  growth  of  some  inverted 
plants  of  the  gooseberry-tree,  which  I  obtained,  many  years  ago,  from 
layers,  gave  me  reason  to  draw  a  different  conclusion ;  for  these  always 
continued  weak  and  dwarfish.  I  do  not,  however,  entertain  the  slightest 
degree  of  doubt  but  that  the  assertion  of  Duhamel  is  perfectly  correct. 

I  intended  to  have  added  some  observations  on  the  reproduction  of  buds 
and  roots  of  trees ;  but  these  would  necessarily  extend  the  present  paper 
to  an  immoderate  length ;  I  shall  therefore  reserve  them  for  a  future 
communication,  and  conclude  with  an  account  of  an  experiment  which 
more  properly  belongs  to  the  paper  I  had  the  honour  to  address  to  you 
last  year,  but  which  had  not  then  succeeded. 

I  have  stated  in  that  paper,  that  the  leaf-stalk,  the  fruit-stalk,  and  the 

*  The  eleventh  plate  (Vegetable  statics)  is  that  to  which,  in  this  place,  I  particularly  allude. 


MOTION    OF    THE    SAP    IN    T^IEES. 


109 


tendril,  of  the  vine,  had  been  successfully  substituted,  in  many  instances, 
for  each  other  ;  but  that  I  had  failed  in  my  efforts  to  engraft  a  bunch  of 
grapes,    by  approach,   on   the   leaf-stalk  ;    owing,   I  conceived,  to   the 
operation  having  been  improperly  performed.     In  those  experiments,  I 
cut  the  leaf-stalk  into  the  form  of  a  wedge,  and  made  an  incision  in  the 
fruit-stalk  adapted  to  receive  it ;  but,  under  such  circumstances,  the  leaf- 
stalk (as  I  had  proved  by  many  experiments)  has  no  power  to  generate 
new  matter ;  and  the  wounds  of  the  fruit-stalk  heal  so  slowly  that  I 
readily  anticipated  the  ill  success  of  the  operation.     In  the  last  spring,  I 
pared  off  similar  portions  of  the  leaf-stalk  and  fruit-stalk ;  and,  bringing 
the  wounded  parts  into  contact,  I  secured  them  closely  together,  by 
means  of  a  bandage,  letting  the  leaf  remain.     Under  these  circumstances 
a  union  took  place  ;  and  the  fruit-stalk  being  then  taken  off  below  the 
point  of  junction  and  the  leaf-stalk  above  it,  the  grapes  drew  their  whole 
nutriment  through  the  remaining  part  of  the  leaf-stalk.     They  did  not, 
however,  acquire  their  full  size  ;  and  the  seeds  were  small,  and,  I  think, 
incapable  of  vegetating  ;  but  this  I  attribute  to  the  want  of  nutriment  in 
quantity  rather  than  in  quality  ;  for  the  union  of  the  vessels  of  the  leaf- 
stalk with  those  of  the  fruit-stalk  was  very  imperfect.     The  grapes, 
which  were  the  purple  Frontignac,  possessed  their  musky  flavour  in  the 
same  degree  with  others  growing  on  the  same  plant. 

There  is  another  experiment  in  my  last  paper,  which  I  will  also  notice 
here ;  because  it  appears  to  lead  to  some  important  conclusions,  and  had 
been  tried  only  in  a  single  instance.  I  have  there  stated,  that  the  stem 
of  a  young  tree  became  elliptical,  by  being  confined  to  move  only  in  the 
segment  of  a  large  circle.  This  experiment  was  successfully  repeated, 
during  the  last  year,  on  other  trees ;  but  I  have  nothing  to  add  to  the 
description  which  I  have  already  given. 


V.— OBSERVATIONS  ON  THE    STATE  IN  WHICH  THE  TRUE   SAP  OF  TREES 
IS  DEPOSITED  DURING  WINTER. 

[Read  before  the  ROYAL  SOCIETY,  January  24,  1805.] 

IT  is  well  known  that  the  fluid,  generally  called  the  sap  in  trees,  ascends 
in  the  spring  and  summer  from  their  roots,  and  that  in  the  autumn  and 
winter  it  is  not,  in  any  considerable  quantity,  found  in  them ;  and  I  have 
observed  in  a  former  paper,  that  this  fluid  rises  wholly  through  the 
alburnum,  or  sap-wood.  But  Duhamel  and  subsequent  naturalists  have 
proved,  that  trees  contain  another  kind  of  sap,  which  they  have  called 


HO  OBSERVATIONS    ON    THE    STATE    OF    THE 

the  true,  or  peculiar  juice,  or  sap  of  the  plant.  Whence  this  fluid  origi- 
nates does  not  appear  to  have  been  agreed  upon  by  naturalists ;  but  I  have 
offered  some  facts  to  prove  that  it  is  generated  by  the  leaf*  ;  and  that  it 
diners  from  the  common  aqueous  sap  owing  to  changes  it  has  undergone 
in  its  circulation  through  that  organ  :  and  I  have  contended  that  from 
this  fluid  (which  Duhamel  has  called  the  sue  propre,  and  which  I  will 
call  the  true  sap)  the  whole  substance,  which  is  annually  added  to  the 
tree,  is  derived.  I  shall  endeavour  in  the  present  paper  to  prove  that 
this  fluid,  in  an  inspissated  state,  or  some  concrete  matter  deposited  by 
it,  exists  during  the  winter  in  the  alburnum,  and  that  from  this  fluid,  or 
substance,  dissolved  in  the  ascending  aqueous  sap,  is  derived  the  matter 
which  enters  into  the  composition  of  the  new  leaves  in  the  spring,  and 
thus  furnishes  those  organs,  which  were  not  wanted  during  the  winter, 
but  which  are  essential  to  the  further  progress  of  vegetation. 

Few  persons  at  all  conversant  with  timber  are  ignorant,  that  the 
alburnum,  or  sap-wood  of  trees,  which  are  felled  in  the  autumn  or  winter, 
is  much  superior  in  quality  to  that  of  other  trees  of  the  same  species, 
which  are  suffered  to  stand  till  the  spring,  or  summer  :  it  is  at  once  more 
firm  and  tenacious  in  its  texture,  and  more  durable.  This  superiority  in 
winter-felled  wood  has  been  generally  attributed  to  the  absence  of  the 
sap  at  that  season  ;  but  the  appearance  and  qualities  of  the  wood  seem 
more  justly  to  warrant  the  conclusion,  that  some  substance  has  been 
added  to,  instead  of  taken  from  it,  and  many  circumstances  induced  me 
to  suspect  that  this  substance  is  generated,  and  deposited  within  it,  in 
the  preceding  summer  and  autumn. 

Duhamel  has  remarked,  and  is  evidently  puzzled  with  the  circum- 
stance, that  trees  perspire  more  in  the  month  of  August,  when  the  leaves 
are  full  grown,  and  when  the  annual  shoots  have  ceased  to  elongate,  than 
at  any  earlier  period  ;  and  we  cannot  suppose  the  powers  of  vegetation  to 
be  thus  actively  employed,  but  in  the  execution  of  some  very  important 
operation.  Bulbous  and  tuberous  roots  are  almost  wholly  generated  after 
the  leaves  and  stems  of  the  plants  to  which  they  belong  have  attained 
their  full  growth  :  and  I  have  constantly  found,  in  my  practice  as  a 
farmer,  that  the  produce  of  my  meadows  has  been  immensely  increased 
when  the  herbage  of  the  preceding  year  had  remained  to  perform  its 
proper  office  till  the  end  of  the  autumn,  on  ground  which  had  been  mowed 
early  in  the  summer.  Whence  I  have  been  led  to  imagine,  that  the 
leaves,  both  of  trees  and  herbaceous  plants,  are  alike  employed,  during 
the  latter  part  of  the  summer,  in  the  preparation  of  matter  calculated  to 

*  See  above,  Paper  No.  III. 


SAP    OP    TREES    DURING    WINTER.  Ill 

afford  food  to  the  expanding  buds  and  blossoms  of  the  succeeding  spring, 
and  to  enter  into  the  composition  of  new  organs  of  assimilation. 

If  the  preceding  hypothesis  be  well  founded,  we  may  expect  to  find  that 
some  change  will  gradually  take  place  in  the  qualities  of  the  aqueous  sap 
of  trees  during  its  ascent  in  the  spring ;  and  that  any  given  portion  of 
winter-felled  wood  will  at  the  same  time  possess  a  greater  degree  of 
specific  gravity,  and  yield  a  larger  quantity  of  extractive  matter,  than  the 
same  quantity  of  wood  which  has  been  felled  in  the  spring  or  in  the  early 
part  of  the  summer.  To  ascertain  these  points  I  made  the  experiments, 
an  account  of  which  I  have  now  the  honour  to  lay  before  you. 

As  early  in  the  last  spring  as  the  sap  had  risen  in  the  sycamore  and 
birch,  I  made  incisions  into  the  trunks  of  those  trees,  some  close  to  the 
ground,  and  others  at  the  elevation  of  seven  feet,  and  I  readily  obtained 
from  each  incision  as  much  sap  as  I  wanted.  Ascertaining  the  specific 
gravity  of  the  sap  of  each  tree,  obtained  at  the  different  elevations,  I  found 
that  of  the  sap  of  the  sycamore  with  very  little  variation,  in  different 
trees,  to  be  1.004  when  extracted  close  to  the  ground,  and  1.008  at  the 
height  of  seven  feet.  The  sap  of  the  birch  was  somewhat  lighter  ;  but 
the  increase  of  its  specific  gravity,  at  greater  elevation,  was  comparatively 
the  same.  When  extracted  near  the  ground  the  sap  of  both  kinds  was 
almost  free  from  taste ;  but  when  obtained  at  a  greater  height,  it  was 
sensibly  sweet.  The  shortness  of  the  trunks  of  the  sycamore  trees,  which 
were  the  subjects  of  my  experiments,  did  not  permit  me  to  extract  the 
sap  at  a  greater  elevation  than  seven  feet,  except  in  one  instance,  and  in 
that,  at  twelve  feet  from  the  ground,  I  obtained  a  very  sweet  fluid,  whose 
specific  gravity  was  1.012. 

I  conceived  it  probable,  that  if  the  sap  in  the  preceding  cases  derived 
any  considerable  portion  of  its  increased  specific  gravity  from  matter  pre- 
viously existing  in  the  alburnum,  I  should  find  some  diminution  of  its 
weight,  when  it  had  continued  to  flow  some  days  from  the  same  incision, 
because  the  alburnum  in  the  vicinity  of  that  incision  would,  under  such 
circumstances,  have  become  in  some  degree  exhausted  :  and  on  compar- 
ing the  specific  gravity  of  the  sap  which  had  flowed  from  a  recent  and  an 
old  incision,  I  found  that  from  the  old  to  be  reduced  to  1.002,  and  that 
from  the  recent  one  to  remain  1.004,  as  in  the  preceding  cases,  the  incision 
being  made  close  to  the  ground.  Wherever  extracted,  whether  close  to 
the  ground,  or  at  some  distance  from  it,  the  sap  always  appeared  to  con- 
tain a  large  portion  of  air. 

In  the  experiments  to  discover  the  variation  in  the  specific  gravity  of 
the  alburnum  of  trees  at  different  seasons,  some  obstacles  to  the  attain- 


112  OBSERVATIONS    ON    THE    STATE    OF    THE 

ment  of  any  very  accurate  results  presented  themselves.  The  wood  of 
different  trees  of  the  same  species,  and  growing  in  the  same  soil,  or  that 
taken  from  different  parts  of  the  same  tree,  possesses  different  degrees  of 
solidity  ;  and  the  weight  of  every  part  of  the  alburnum  appears  to  increase 
with  its  age,  the  external  layers  being  the  lightest.  The  solidity  of  wood 
varies  also  with  the  greater  or  less  rapidity  of  its  growth.  These  sources 
of  error  might  apparently  have  been  avoided  by  cutting  off,  at  different 
seasons,  portions  of  the  same  trunk  or  branch  :  but  the  wound  thus  made 
might,  in  some  degree,  have  impeded  the  due  progress  of  the  sap  in  its 
ascent,  and  the  part  below  might  have  been  made  heavier  by  the  stagna- 
tion of  the  sap,  and  that  above  lighter  by  privation  of  its  proper  quantity 
of  nutriment.  The  most  eligible  method  therefore  which  occurred  to 
me,  was  to  select  and  mark  in  the  winter  some  of  the  poles  of  an  oak 
coppice,  where  all  are  of  equal  age,  and  where  many,  of  the  same  size  and 
growing  with  equal  vigour,  spring  from  the  same  stool.  One  half  of  the 
poles  which  I  marked  and  numbered  were  cut  on  the  31st  of  December 
1803,  and  the  remainder  on  the  15th  of  the  following  May,  when  the 
leaves  were  nearly  half  grown.  Proper  marks  were  put  to  distinguish  the 
winter-felled  from  the  summer-felled  poles,  the  bark  being  left  on  all,  and 
all  being  placed  in  the  situation  to  dry. 

In  the  beginning  of  August  I  cut  off  nearly  equal  portions  from  a 
winter  and  summer-felled  pole,  which  had  both  grown  on  the  same  stool ; 
and  both  portions  were  then  put  in  a  situation,  where,  during  the  seven 
succeeding  weeks,  they  were  kept  very  warm  by  a  fire.  The  summer- 
felled  wood  was,  when  put  to  dry,  the  most  heavy ;  but  it  evidently  con- 
tained much  more  water  than  the  other,  and,  partly  at  least  from  this 
cause,  it  contracted  much  more  in  drying.  In  the  beginning  of  October 
both  kinds  appeared  to  be  perfectly  dry,  and  I  then,  ascertained  the 
specific  gravity  of  the  winter-felled  wood  to  be  0.679,  and  that  of  the 
summer-felled  wood  to  be  0.609  ;  after  each  had  been  immersed  five 
minutes  in  water. 

This  difference  of  ten  per  cent,  was  considerably  more  than  I  had  anti- 
cipated, and  it  was  not  till  I  had  suspended  and  taken  off  from  the  balance 
each  portion,  at  least  ten  times,  that  I  ceased  to  believe  that  some  error 
had  occurred  in  the  experiment :  and  indeed  I  was  not  at  last  satisfied 
till  I  had  ascertained  by  means  of  compasses  adapted  to  the  measurement 
of  solids,  that  the  winter-felled  pieces  of  wood  were  much  less  than  the 
others  which  they  equalled  in  weight. 

The  pieces  of  wood,  which  had  been  the  subjects  of  these  experiments, 
were  again  put  to  dry,  with  other  pieces  of  the  same  poles,  and  I  yesterday 


SAP    OF    TREES    DURING    WINTER.  113 

ascertained  the  specific  gravity  of  both  with  scarcely  any  variation  in  the 
result.  But  when  I  omitted  the  medulla,  and  parts  adjacent  to  it,  and 
used  the  layers  of  wood  which  had  been  more  recently  formed,  I  found 
the  specific  gravity  of  the  winter-felled  wood  to  be  only  0.583,  and  that 
of  the  summer-felled  to  be  0.533  ;  and  trying  the  same  experiment  with 
similar  pieces  of  wood,  but  taken  from  poles  which  had  grown  on  a 
different  stool,  the  specific  gravity  of  the  winter-felled  wood  was  0.588, 
and  that  of  the  summer-felled  0.534. 

It  is  evident  that  the  whole  of  the  preceding  difference  in  the  specific 
gravity  of  the  winter  and  summer  felled  wood  might  have  arisen  from  a 
greater  degree  of  contraction  in  the  former  kind,  whilst  drying ;  I  there- 
fore proceeded  to  ascertain  whether  any  given  portion  of  it,  by  weight, 
would  afford  a  greater  quantity  of  extractive  matter,  when  steeped  in 
water.  Having  therefore  reduced  to  small  fractions  1000  grains  of  each 
kind,  I  poured  on  each  portion  six  ounces  of  boiling  water ;  and  at  the 
end  of  twenty-four  hours,  when  the  temperature  of  the  water  had  sunk 
to  60°,  I  found  that  the  winter-felled  wood  had  communicated  a  much 
deeper  colour  to  the  water  in  which  it  had  been  infused,  and  had  raised 
its  specific  gravity  to  1.002.  The  specific  gravity  of  the  water  in  which 
the  summer-felled  wood  had,  in  the  same  manner,  been  infused  was  1.001 . 
The  wood  in  all  the  preceding  cases  was  taken  from  the  upper  parts  of 
the  poles,  about  eight  feet  from  the  ground. 

Having  observed,  in  the  preceding  experiments,  that  the  sap  of  the 
sycamore  became  specifically  lighter  when  it  had  continued  to  flow  during 
several  days  from  the  same  incision,  I  concluded  that  the  alburnum  in 
the  vicinity  of  such  incision  had  been  deprived  of  a  larger  portion  of  its 
concrete  or  inspissated  sap  than  in  other  parts  of  the  same  tree  :  and  I 
therefore  suspected  that  I  should  find  similar  effects  to  have  been  pro- 
duced by  the  young  annual  shoots  and  leaves  ;  and  that  any  Driven  weight 
of  the  alburnum  in  their  vicinity  would  be  found  to  contain  less  extractive 
matter  than  an  equal  portion  taken  from  the  lower  parts  of  the  same 
pole,  where  no  annual  shoots  or  leaves  had  been  produced. 

No  information  could  in  this  case  be  derived  from  the  difference  in  the 
specific  gravity  of  the  wood  ;  because  the  substance  of  every  tree  is  most 
dense  and  solid  in  the  lower  parts  of  its  trunk  :  and  I  could  on  this  account 
judge  only  from  the  quantity  of  extractive  matter  which  equal  portions  of 
the  two  kinds  of  wood  would  afford.  Having  therefore  reduced  to  pieces 
several  equal  portions  of  wood  taken  from  different  parts  of  the  same 
poles,  which  had  been  felled  in  May,  I  poured  on  each  portion  an  equal 
quantity  of  boiling  water,  which  I  suffered  to  remain  twenty  hours,  as  in 


114  OBSERVATIONS    ON    THE    STATE    OF    THE 

the  preceding  experiments :  and  I  then  found  that  in  some  instances  the 
wood  from  the  lower,  and  in  others  that  from  the  upper  parts  of  the  poles, 
had  given  to  the  water  the  deepest  colour  and  greatest  degree  of  specific 
gravity ;  but  that  all  had  afforded  much  extractive  matter,  though  in 
every  instance  the  quantity  yielded  was  much  less  than  I  had,  in  all  cases, 
found  in  similar  infusions  of  winter-felled  wood. 

It  appears,  therefore,  that  the  reservoir  of  matter  deposited  in  the 
alburnum  is  not  wholly  exhausted  in  the  succeeding  spring :  and  hence 
we  are  able  to  account  for  the  several  successions  of  leaves  and  buds 
which  trees  are  capable  of  producing  when  those  previously  protruded 
have  been  destroyed  by  insects,  or  other  causes,  and  for  the  extremely 
luxuriant  shoots  which  often  spring  from  the  trunks  of  trees,  whose 
branches  have  been  long  in  a  state  of  decay. 

I  have  also  some  reason  to  believe  that  the  matter  deposited  in  the 
alburnum  remains  unemployed  in  some  cases  during  several  successive 
years  :  it  does  not  appear  probable  that  it  can  be  all  employed  by  trees 
which,  after  having  been  transplanted,  produce  very  few  leaves,  or  by 
those  which  produce  neither  blossoms  nor  fruit.  In  making  experiments 
in  1802,  to  ascertain  the  manner  in  which  the  buds  of  trees  are  repro- 
duced, I  cut  off  in  the  winter  all  the  branches  of  a  very  large  old  pear- 
tree,  at  a  small  distance  from  the  trunk  ;  and  I  pared  off,  at  the  same 
time,  the  whole  of  the  lifeless  external  bark.  The  age  of  this  tree,  I  have 
good  reasons  to  believe,  somewhat  exceeded  two  centuries  :  its  extremities 
were  generally  dead  ;  and  it  afforded  few  leaves,  and  no  fruit ;  and  I  had 
long  expected  every  successive  year  to  terminate  its  existence.  After 
being  deprived  of  its  external  bark,  and  of  all  its  buds,  no  marks  of  vege- 
tation appeared  in  the  succeeding  spring,  or  early  part  of  the  summer  : 
but  in  the  beginning  of  July  numerous  buds  penetrated  through  the  bark 
in  every  part,  many  leaves  of  large  size  everywhere  appeared,  and  in  the 
autumn  every  part  was  covered  with  very  vigorous  shoots  exceeding,  in 
the  aggregate,  two  feet  in  length.  The  number  of  leaves  which,  in  this 
case,  sprang  at  once  from  the  trunk  and  branches  appeared  to  me  greatly 
to  exceed  the  whole  of  those  which  the  tree  had  borne  in  the  three  pre- 
ceding seasons  ;  and  I  cannot  believe  that  the  matter  which  composed 
these  buds  and  leaves  could  have  been  wholly  prepared  by  the  feeble 
v  vegetation  arid  scanty  foliage  of  the  preceding  year. 

But  whether  the  substance  which  is  found  in  the  alburnum  of  winter- 
felled  trees,  and  which  disappears  in  part  in  the  spring  and  early  part  of 
the  summer,  be  generated  in  one  or  in  several  preceding  years,  there  seem 
to  be  strong  grounds  of  probability,  that  this  substance  enters  into  the 


SAP  OF  TREES  DURING  WINTER.  115 

composition  of  the  leaf :  for  we  have  abundant  reason  to  believe  that  this 
organ  is  the  principal  agent  of  assimilation  ;  and  scarcely  anything  can 
be  more  contrary  to  every  conclusion  we  should  draw  from  analogical 
reasoning  and  comparison  of  the  vegetable  with  the  animal  economy,  or 
in  itself  more  improbable,  than  that  the  leaf,  or  any  other  organ,  should 
singly  prepare  and  assimilate  immediately  from  the  crude  aqueous  sap 
that  matter  which  composes  itself. 

It  has  been  contended  *  that  the  buds  themselves  contain  the  nutriment 
necessary  for  the  minute  unfolding  leaves  :  but  trees  possess  a  power  to 
reproduce  their  buds,  and  the  matter  necessary  to  form  these  buds  must 
evidently  be  derived  from  some  other  source ;  nor  does  it  appear  probable 
that  the  young  leaves  very  soon  enter  on  this  office,  for  the  experiments 
of  Ingenhouz  prove  that  their  action  on  the  air  which  surrounds  them  is 
very  essentially  different  from  that  of  full-grown  leaves.  It  is  true  that 
buds  in  many  instances  will  vegetate,  and  produce  trees,  when  a  very 
small  portion  only  of  alburnum  remains  attached  to  them  ;  but  the  first 
efforts  of  vegetation  in  such  buds  are  much  more  feeble  than  in  others  to 
which  a  larger  quantity  of  alburnum  is  attached,  and  therefore  we  have, 
in  this  case,  no  grounds  to  suppose  that  the  leaves  derive  their  first 
nutriment  from  the  crude  sap. 

It  is  also  generally  admitted,  from  the  experiments  of  Bonnet  and 
Du  Hamel,  which  I  have  repeated  with  the  same  result,  that  in  the 
cotyledons  of  the  seed  is  deposited  a  quantity  of  nutriment  for  the  bud 
which  every  seed  contains ;  and  though  no  vessels  can  be  traced  -|-  which 
lead  immediately  from  the  cotyledons  to  the  bud  or  plumula,  it  is  not 
difficult  to  point  out  a  more  circuitous  passage,  which  is  perfectly  similar 
to  that  through  which  I  conceive  the  sap  to  be  carried  from  the  leaves 
to  the  buds  in  the  subsequent  growth  of  the  tree  ;  and  I  am  in  possession 
of  many  facts  to  prove  that  seedling  trees,  in  the  first  stage  of  their 
existence,  depend  entirely  on  the  nutriment  afforded  by  the  cotyledons  ; 
and  that  they  are  greatly  injured,  and  in  many  instances  killed,  by  being 
put  to  vegetate  in  rich  mould. 

We  have  much  more  decisive  evidence  that  bulbous  and  tuberous 
rooted  plants  contain  the  matter  within  themselves  which  subsequently 
composes  their  leaves ;  for  we  see  them  vegetate  even  in  dry  rooms  on 
the  approach  of  spring ;  and  many  bulbous  rooted  plants  produce  their 
leaves  and  flowers  with  nearly  the  same  vigour  by  the  application  of 
water  only,  as  they  do  when  growing  in  the  best  mould.  But  the  water 

*  Thomson's  Chemistry.  f  Hedwig. 

i  2 


116  OBSERVATIONS    ON    THE    STATE    OF    THE 

in  this  case,  provided  that  it  be  perfectly  pure,  probably  affords  little  or 
no  food  to  the  plant,  and  acts  only  by  dissolving  the  matter  prepared  and 
deposited  in  the  preceding  year  ;  and  hence  the  root  becomes  exhausted 
and  spoiled  :  and  Hassenfratz  found  that  the  leaves  and  flowers  and 
roots  of  such  plants  afforded  no  more  carbon  than  he  had  proved  to  exist 
in  bulbous  roots  of  the  same  weight,  whose  leaves  and  flowers  had  never 
expanded. 

As  the  leaves  and  -flowers  of  the  hyacinth,  in  the  preceding  case, 
derived  their  matter  from  the  bulb,  it  appears  extremely  probable  that 
the  blossoms  of  trees  receive  their  nutriment  from  the  alburnum,  particu- 
larly as  the  blossoms  of  many  species  precede  their  leaves ;  and,  as  the 
roots  of  plants  become  weakened  and  apparently  exhausted  when  they 
have  afforded  nutriment  to  a  crop  of  seed,  we  may  silspect  that  a  tree, 
which  has  borne  much  fruit  in  one  season,  becomes  in  a  similar  way 
exhausted,  and  incapable  of  affording  proper  nutriment  to  a  crop  in  the 
succeeding  year.  And  I  am  much  inclined  to  believe  that  were  the  wood 
of  a  tree  in  this  state  accurately  weighed,  it  would  be  found  specifically 
lighter  than  that  of  a  similar  tree,  which  had  not  afforded  nutriment  to 
fruit  or  blossoms  in  the  preceding  year  or  years. 

If  it  be  admitted  that  the  substance  which  enters  into  the  composition 
of  the  first  leaves  in  the  spring  is  derived  from  matter  which  has  under- 
gone some  previous  preparation  within  the  plant  (and  I  am  at  a  loss  to 
conceive  on  what  grounds  this  can  be  denied,  in  bulbous  and  tuberous 
rooted  plants  at  least),  it  must  also  be  admitted  that  the  leaves  which 
are  generated  in  the  summer  derive  their  substance  from  a  similar 
source ;  and  this  cannot  be  conceded  without  a  direct  admission  of  the 
existence  of  vegetable  circulation,  which  is  denied  by  so  many  eminent 
naturalists.  I  have  not,  however,  found  in  their  writings  a  single  fact  to 
disprove  its  existence,  nor  any  great  weight  in  their  arguments,  except 
those  drawn  from  two  important  errors  in  the  admirable  works  of  Hales 
and  Duhamel,  which  I  have  noticed  in  a  former  memoir.  I  shall 
therefore  proceed  to  point  out  the  channels  through  which  I  conceive  the 
circulating  fluids  to  pass. 

When  a  seed  is  deposited  in  the  ground,  or  otherwise  exposed  to  a 
proper  degree  of  heat  and  moisture  and  exposure  to  air,  water  is 
absorbed  by  the  cotyledons,  and  the  young  radicle  or  root  is  emitted- 
At  this  period,  and  in  every  subsequent  stage  of  the  growth  of  the  root> 
it  increases  in  length  by  the  addition  of  new  parts  to  its  apex,  or  point, 
and  not  by  any  general  distension  of  its  vessels  and  fibres  ;  and  the 
experiments  of  Bonnet  and  Duhamel  leave  little  grounds  of  doubt  but 


SAP    OF    TREES    DURING    WINTER.  117 

that  the  new  matter  which  is  added  to  the  point  of  the  root  descends 
from  the  cotyledons.  The  first  motion  therefore  of  the  fluids  in  plants 
is  downwards,  towards  the  point  of  the  root ;  and  the  vessels  which 
appear  to  carry  them  are  of  the  same  kind  with  those  which  are  subse- 
quently found  in  the  bark,  where  I  have,  on  a  former  occasion,  endeavoured 
to  prove  that  they  execute  the  same  office. 

In  the  last  spring  I  examined  almost  every  day  the  progressive  changes 
which  take  place  in  the  radicle  emitted  by  the  horse-chestnut :  I  found 
it,  at  its  first  existence  and  until  it  was  some  weeks  old,  to  be  incapable 
of  absorbing  coloured  infusions  when  its  point  was  taken  off,  and  I  was 
totally  unable  to  discover  any  alburnous  tubes  through  which  the  sap 
absorbed  from  the  ground,  in  the  subsequent  growth  of  the  tree,  ascends ; 
but  when  the  roots  were  considerably  elongated,  alburnous  tubes  formed ; 
and,  as  soon  as  they  had  acquired  some  degree  of  firmness  in  their 
consistence,  they  appeared  to  enter  on  their  office  of  carrying  up  the 
aqueous  sap,  and  the  leaves  of  the  plumula  then,  and  not  sooner, 
expanded. 

The  leaf  contains  at  least  three  kinds  of  tubes  : — the  first  is  what  in  a 
former  paper  I  have  called  the  central  vessel,  through  which  the  aqueous 
sap  appears  to  be  carried,  and  through  which  coloured  infusions  readily 
pass,  from  the  alburnous  tubes  into  the  leaf-stalk.  These  vessels  are 
always  accompanied  by  spiral  tubes,  which  do  not  appear  to  carry  any 
liquid ;  but  there  is  another  vessel  which  appears  to  take  its  origin  from 
the  leaf,  and  which  descends  down  the  internal  bark,  and  contains  the 
true  or  prepared  sap.  When  the  leaf  has  attained  its  proper  growth,  it 
seems  to  perform  precisely  the  office  of  the  cotyledon ;  but  being  exposed 
to  the  air,  and  without  the  same  means  to  acquire,  or  the  substance  to 
retain  moisture,  it  is  fed  by  the  alburnous  tubes  and  central  vessels. 

The  true  sap  now  appears  to  be  discharged  from  the  leaf,  as  it  was 
previously  from  the  cotyledon,  into  the  vessels  of  the  bark,  and  to  be 
employed  in  the  formation  of  new  alburnous  tubes  between  the  base  of 
the  leaf  and  the  root.  From  these  alburnous  tubes  spring  other  central 
vessels  and  spiral  tubes,  which  enter  into  and  possibly  give  existence  to 
other  leaves ;  and  thus  by  a  repetition  of  the  same  process  the  young 
tree  or  annual  shoot  continues  to  acquire  new  parts,  which  apparently 
are  formed  from  the  ascending  aqueous  sap. 

But  it  has  been  proved  by  Duhamel  that  a  fluid  similar  to  that  which 
is  found  in  the  true  sap-vessels  of  the  bark  exists  also  in  the  alburnum, 
and  this  fluid  is  extremely  obvious  in  the  fig,  and  other  trees,  whose  true 
sap  is  white  or  coloured.  The  vessels  which  contain  this  fluid  in  the 


]  18  OBSERVATIONS    ON    THE    STATE    OP    THE 

alburnum  are  in  contact  with  those  which  carry  up  the  aqueous  sap  ; 
and  it  does  not  appear  probable  that,  in  a  body  so  porous  as  wood,  fluids 
so  near  each  other  should  remain  wholly  unmixed.  I  must  therefore 
conclude  that  when  the  true  sap  has  been  delivered  from  the  cotyledon 
or  leaf  into  the  returning  or  true  sap-vessels  of  the  bark,  one  portion  of 
it  secretes  through  the  external  cellular,  or  more  probably  glandular 
substance  of  the  bark,  and  generates  a  new  epidermis  where  that  is  to  be 
formed  ;  and  that  the  other  portion  of  it  secretes  through  the  internal 
glandular  substance  of  the  bark,  where  one  part  of  it  produces  the  new 
layer  of  wood,  and  the  remainder  enters  the  pores  of  the  wood  already 
formed,  and  subsequently  mingles  with  the  ascending  aqueous  sap  ;  which 
thus  becomes  capable  of  affording  the  matter  necessary  to  form  new  buds 
and  leaves. 

It  has  been  proved  in  the  preceding  experiments  on  the  ascending  sap 
of  the  sycamore  and  birch,  that  that  fluid  does  not  approach  the  buds 
and  unfolding  leaves  in  the  spring,  in  the  state  in  which  it  is  absorbed 
from  the  earth ;  and  therefore  we  may  conclude  that  the  fluid  which 
enters  into  and  circulates  through  the  leaves  of  plants,  as  the  blood 
through  the  lungs  of  animals,  consists  of  a  mixture  of  the  true  sap  or 
blood  of  the  plant  with  matter  more  recently  absorbed,  and  less  perfectly 
assimilated. 

It  appears  probable  that  the  true  sap  undergoes  a  considerable  change  on 
its  mixture  with  the  ascending  aqueous  sap ;  for  this  fluid  in  the  sycamore 
has  been  proved  to  become  more  sensibly  sweet  in  its  progress  from  the 
roots  in  the  spring,  and  the  liquid  which  flows  from  the  wounded  bark  of 
the  same  tree  is  also  sweet ;  but  I  have  never  been  able  to  detect  the 
slightest  degree  of  sweetness  in  decoctions  of  the  sycamore  wood  in 
winter.  I  am  therefore  inclined  to  believe  that  the  saccharine  matter 
existing  in  the  ascending  sap  is  not  immediately,  or  wholly,  derived  from 
the  fluid  which  had  circulated  through  the  leaf  in  the  preceding  year ; 
but  that  it  is  generated  by  a  process  similar  to  that  of  the  germination 
of  seeds,  and  that  the  same  process  is  always  going  forward  during  the 
spring  and  summer,  as  long  as  the  tree  continues  to  generate  new  organs. 
But  towards  the  conclusion  of  the  summer  I  conceive  that  the  true  sap 
simply  accumulates  in  the  alburnum,  and  thus  adds  to  the  specific  gravity 
of  winter-felled  wood,  and  increases  the  quantity  of  its  extractive  matter. 

I  have  some  reasons  to  believe  that  the  true  sap  descends  through  the 
alburnum  as  well  as  through  the  bark,  and  I  have  been  informed  that  if 
the  bark  be  taken  from  the  trunks  of  trees  in  the  spring,  and  such  trees 
be  suffered  to  grow  till  the  following  winter,  the  alburnum  acquires  a 


SAP    OF    TREES    DURING    WINTER.  119 

great  degree  of  hardness  and  durability.  If  subsequent  experiments 
prove  that  the  true  sap  descends  through  the  alburnum,  it  will  be  easy  to 
point  out  the  cause  why  trees  continue  to  vegetate  after  all  communi- 
cation between  the  leaves  and  roots,  through  the  bark,  has  been  inter- 
cepted ;  and  why  some  portion  of  alburnous  matter  is  in  all  trees  * 
generated  below  incisions  through  the  bark. 

It  was  my  intention  this  year  to  have  troubled  you  with  some  observa- 
tions on  the  reproductions  of  the  buds  and  roots  of  trees ;  but  as  the 
subject  of  the  paper  which  I  have  now  the  honour  to  address  to  you 
appeared  to  be  of  more  importance,  I  have  deferred  those  observations 
to  a  future  opportunity;  and  I  shall  at  present  only  observe,  that  I 
conceive  myself  to  be  in  possession  of  facts  to  prove  that  both  buds  and 
roots  originate  from  the  alburnous  substance  of  plants,  and  not,  as  is,  I 
believe,  generally  supposed,  from  the  bark. 


VI.— ON    THE    REPRODUCTION    OF    BUDS. 

[Read  before  the  ROYAL  SOCIETY,  May  23,  1805.] 

EVERY  tree,  in  the  ordinary  course  of  its  growth,  generates  in  each 
season  those  buds  which  expand  in  the  succeeding  spring  ;  and  the  buds 
thus  generated  contain,  in  many  instances,  the  whole  of  the  leaves  which 
appear  in  the  following  summer.  But  if  these  buds  be  destroyed  during 
the  winter  or  early  part  of  the  spring,  other  buds,  in  many  species  of 
trees,  are  generated,  which  in  every  respect  perform  the  office  of  those 
which  previously  existed,  except  that  they  never  afford  fruit  or  blossoms. 
This  reproduction  of  buds  has  not  escaped  the  notice  of  naturalists ; 
but  it  does  not  appear  to  have  been  ascertained  by  them,  from  which 
amongst  the  various  substances  of  the  tree  the  buds  derive  their  origin. 

Duhamel  conceived  that  reproduced  buds  sprang  from  pre-organized 
germs ;  but  the  existence  of  such  germs  has  not,  in  any  instance,  been 
proved,  and  it  is  well  known  that  the  roots  and  trunk,  and  branches,  of 
many  species  of  trees  will,  under  proper  management,  afford  buds  from 
every  part  of  their  surfaces ;  and  therefore,  if  this  hypothesis  be  well 
founded,  many  millions  of  such  germs  must  be  annually  generated  in  every 
large  tree  ;  not  one  of  which  in  the  ordinary  course  of  nature  will  come 

*  I  have  in  a  former  paper  stated  that  the  perpendicular  shoots  of  the  vine  form  an  exception. 
I  spoke  on  the  authority  of  numerous  experiments  ;  but  they  had  been  made  late  in  the  summer  ; 
and  on  repeating  the  same  experiments  at  an  earlier  period,  I  found  the  result  in  conformity 
with  my  experiments  on  other  trees. 


120  ON    THE    REPRODUCTION    OF    BUDS. 

into  action ;  and  as  nature,  amidst  all  its  exuberance,  does  not  abound 
in  useless  productions,  the  opinions  of  this  illustrious  physiologist  are  in 
this  case  probably  erroneous. 

Other  naturalists  have  supposed  the  buds,  when  reproduced,  to  spring 
from  the  plexus  of  vessels  which  constitutes  the  internal  bark;  and 
this  opinion  is,  I  believe,  much  entertained  by  modern  botanists  ;  it 
nevertheless  appears  to  be  unfounded,  as  the  facts  I  shall  proceed  to 
state  will  evince. 

If  the  fruit-stalks  of  the  sea-cale  (Crambe  maritima)  be  cut  off  near 
the  ground  in  the  spring,  the  medullary  substance  within  that  part  of 
the  stalk  which  remains  attached  to  the  root  decays ;  and  a  cup  is 
thus  formed,  in  which  water  collects  in  the  succeeding  winter.  The  sides 
of  this  cup  consist  of  a  woody  substance,  which  in  its  texture  and  office, 
and  mode  of  generation,  agrees  perfectly  with  the  alburnum  of  trees  ; 
and  I  conceive  it  to  be  as  perfect  alburnum  as  the  white  wood  of  the 
oak  or  elm ;  and  from  the  interior  part  of  this  substance  within  the  cup, 
1  have  frequently  observed  new  buds  to  be  generated  in  the  ensuing 
spring.  It  is  sufficiently  obvious  that  the  buds  in  this  case  do  not  spring 
from  the  bark  ;  but  it  is  not  equally  evident  that  they  might  not  have 
sprung  from  some  remains  of  the  medulla. 

In  the  autumn  of  1802  I  discovered  that  the  potato  possessed  a 
similar  power  of  reproducing  its  buds.  Some  plants  of  this  species  had 
been  set  rather  late  in  the  preceding  spring,  in  very  dry  ground,  where 
through  want  of  moisture  they  vegetated  very  feebly  ;  and  the  portions 
of  the  old  roots  remained  sound  and  entire  till  the  succeeding  autumn. 
Being  then  moistened  by  rain,  many  small  tubers  were  generated  on  the 
surfaces  made  by  the  knife  in  dividing  the  roots  into  cuttings  ;  and  the 
buds  of  these,  in  many  instances,  elongated  into  runners,  which  gave 
existence  to  other  tubers,  some  of  which  I  had  the  pleasure  to  send 
to  you. 

I  have  in  a  former  paper  remarked,  that  the  potato  consists  of  four 
distinct  substances,  the  epidermis,  the  true  skin,  the  bark,  and  its  internal 
substance,  which  from  its  mode  of  formation,  and  subsequent  office,  I 
have  supposed  to  be  alburnous  :  there  is  also  in  the  young  tuber  a  trans- 
parent line  through  the  centre,  which  is  probably  its  medulla.  The  buds 
and  runners  sprang  from  the  substance  which  I  conceive  to  be  the  albur- 
num of  the  root,  and  neither  from  the  central  part  of  it,  nor  from  the 
surface  in  contact  with  the  bark.  It  must,  however,  be  admitted,  that 
the  internal  substance  of  the  potato  corresponds  more  nearly  with  our 
ideas  of  a  medullary  than  of  an  alburnous  substance,  and  therefore  this, 


ON  THE  REPRODUCTION  OF  BUDS.  121 

with  the  preceding  facts,  is  adduced  to  prove  only  that  the  reproduced 
buds  of  these  plants  are  not  generated  by  the  cortical  substance  of  the 
root :  and  1  shall  proceed  to  relate  some  experiments  on  the  apple,  and 
pear,  and  plum-tree,  which  I  conceive  to  prove  that  the  reproduced 
buds  of  those  plants  do  not  spring  from  the  medulla. 

Having  raised  from  seeds  a  very  considerable  number  of  plants  of  each 
of  these  species  in  1802,  I  partly  disengaged  them  from  the  soil  in  the 
autumn,  by  digging  round  each  plant,  which  was  then  raised  about  two 
inches  above  its  former  level.  A  part  of  the  mould  was  then  removed, 
and  the  plants  were  cut  off  about  an  inch  below  the  points  where  the 
seed-leaves  formerly  grew;  and  a  portion  of  the  root,  about  an  inch 
long,  without  any  bud  upon  it,  remained  exposed  to  the  air  and  light. 
In  the  beginning  of  April  I  observed  many  small  elevated  points  on  the 
bark  of  these  roots,  and,  removing  the  whole  of  the  cortical  substance, 
I  found  that  the  elevations  were  occasioned  by  small  protuberances  on 
the  surfaces  of  the  alburnum.  As  the  spring  advanced,  many  minute 
red  points  appeared  to  perforate  the  bark ;  these  soon  assumed  the  cha- 
racter of  buds,  and  produced  shoots,  in  every  respect  similar  to  those 
which  would  have  sprung  from  the  organized  buds  of  the  preceding  year. 
Whether  the  buds  thus  reproduced  derived  any  portion  of  their  component 
parts  from  the  bark  or  not,  I  shall  not  venture  to  decide  ;  but  I  am  much 
disposed  to  believe  that,  like  those  of  the  potato,  they  sprang  from 
the  alburnous  substance  solely. 

The  space,  however,  in  the  annual  root,  between  the  medulla  and  the 
bark  is  very  small ;  and  therefore  it  may  be  contended  that  the  buds  in 
these  instances  may  have  originated  from  the  medulla.  I  therefore 
thought  it  necessary  to  repeat  similar  experiments  on  the  roots  and 
trunks  of  old  trees,  and  by  these  the  buds  were  reproduced  precisely  in 
the  same  manner  as  the  annual  roots :  and  therefore,  conceiving  myself 
to  have  proved  in  a  former  memoir*,  that  the  substance  which  has  been 
called  the  medullary  process  does  not  originate  from  the  medulla,  I  must 
conclude  that  reproduced  buds  do  not  spring  from  that  substance. 

I  have  remarked  in  a  paper,  laid  before  the  Royal  Society  in 
the  commencement  of  the  present  year,  that  the  alburnous  tubes,  at 
their  termination  upwards,  invariably  join  the  central  vessels,  and  that 
these  vessels  which  appear  to  derive  their  origin  from  the  alburnous 
tubes,  convey  nutriment,  and  probably  give  existence  to  new  buds 
and  leaves.  It  is  also  evident,  from  the  facility  with  which  the  rising 
sap  is  transferred  from  one  side  of  a  wounded  tree  to  the  other, 
*  See  above,  the  Paper  No.  III. 


I 

122  ON    THE    REPRODUCTION    OF    BUDS. 

that  the  alburnous  tubes  possess  lateral,  as  well  as  terminal  orifices :  and 
it  does  not  appear  improbable  that  the  lateral  as  well  as  the  terminal 
orifices  of  the  alburnous  tubes  may  possess  the  power  to  generate  central 
vessels  ;  which  vessels  evidently  feed,  if  they  do  not  give  existence  to,  the 
reproduced  buds  and  leaves.  And  therefore,  as  the  preceding  experi- 
ments appear  to  prove  that  the  buds  neither  spring  from  the  medulla  nor 
the  bark,  I  am  much  inclined  to  believe  that  they  are  generated  by  central 
vessels  which  spring  from  the  lateral  orifices  of  the  alburnous  tubes.  The 
practicability  of  propagating  some  plants  from  their  leaves  may  seem  to 
stand  in  opposition  to  this  hypothesis  ;  but  the  central  vessel  is  always  a 
component  part  of  the  leaf,  and  from  it  the  bud  and  young  plant  probably 
originate. 

I  expected  to  discover  in  seeds  a  similar  power  to  regenerate  their 
buds ;  for  the  cotyledons  of  these,  though  dissimilar  in  organisation,  exe- 
cute the  office  of  the  alburnum,  and  contain  a  similar  reservoir  of  nutri- 
ment, and  at  once  supply  the  place  of  the  alburnum  and  the  leaf.  But 
no  experiments  which  I  have  yet  been  able  to  make,  have  been  decisive, 
owing  to  the  difficulty  of  ascertaining  the  number  of  buds  previously 
existing  within  the  seed.  Few,  if  any,  seeds,  I  have  reason  to  believe, 
contain  less  than  three  buds,  one  only  of  which,  except  in  cases  of  acci- 
dent, germinates,  and  some  seeds  appear  to  contain  a  much  greater  num- 
ber. The  seed  of  the  peach  appears  to  be  provided  with  ten  or  twelve 
leaves,  each  of  which  probably  covers  the  rudiment  of  a  bud,  and  the 
seeds,  like  the  buds  of  the  horse-chestnut,  contain  all  the  leaves,  and 
apparently  all  the  buds  of  the  succeeding  year :  and  I  have  never  been 
able  to  satisfy  myself  that  all  the  buds  were  eradicated  without  having 
destroyed  the  base  of  the  plumule,  in  which  the  power  of  reproducing 
buds  probably  resides,  if  such  power  exists. 

Nature  appears  to  have  denied  to  annual  and  biennial  plants  (at  least 
to  those  which  have  been  the  subjects  of  my  experiments)  the  power 
which  it  has  given  to  perennial  plants  to  reproduce  their  buds;  but 
nevertheless  some  biennials  possess,  under  peculiar  circumstances,  a  very 
singular  resource,  when  all  their  buds  have  been  destroyed.  A  turnip, 
bred  between  the  English  and  Swedish  variety,  from  which  I  had  cut  off 
the  greater  part  of  its  fruit-stalks,  and  of  which  all  the  buds  had  been 
destroyed,  remained  some  weeks  in  an  apparently  dormant  state  ;  after 
which  the  first  seed  in  each  pod  germinated,  and  bursting  the  seed-vessel, 
seemed  to  execute  the  office  of  a  bud  and  leaves  to  the  parent  plant, 
during  the  short  remaining  term  of  its  existence,  when  its  preternatural 
foliage  perished  with  it.  Whether  this  property  be  possessed  by  other 


ON    THE    REPRODUCTION    OF    BUDS.  123 

biennial  plants  in  common  with  the  turnip  or  not,  I  am  not  at  present  in 
possession  of  facts  to  decide,  not  having  made  precisely  the  same  experi- 
ment on  any  other  plant. 

I  will  take  this  opportunity  to  correct  an  inference  that  I  have  drawn 
in  a  former  paper  *,  which  the  facts  (though  quite  correctly  stated)  do 
not,  on  subsequent  repetition  of  the  experiment,  appear  to  justify.  I 
have  stated,  that  when  a  perpendicular  shoot  of  the  vine  was  inverted  to 
a  depending  position,  and  a  portion  of  its  bark  between  two  circular 
incisions  round  the  stem  removed,  much  more  new  wood  was  generated 
on  the  lower  lip  of  the  wound,  become  uppermost  by  the  inverted  position 
of  the  branch,  than  on  the  opposite  lip,  which  would  not  have  happened 
had  the  branch  continued  to  grow  erect,  and  I  have  inferred  that  this 
effect  was  produced  by  sap  which  had  descended  by  gravitation  from  the 
leaves  above.  But  the  branch  was,  as  I  have  there  stated,  employed  as 
a  layer,  and  the  matter  which  would  have  accumulated  on  the  opposite 
lip  of  the  wound  had  been  employed  in  the  formation  of  roots,  a  circum- 
stance which  at  that  time  escaped  my  attention.  The  effects  of  gravita- 
tion on  the  motion  of  the  descending  sap,  and  consequent  growth  of 
plants,  are,  I  am  well  satisfied,  from  a  great  variety  of  experiments,  very 
great ;  but  it  will  be  very  difficult  to  discover  any  method  by  which  the 
extent  of  its  operation  can  be  accurately  ascertained.  For  the  vessels 
which  convey  and  impel  •}•  the  true  sap,  or  fluid  from  which  the  new 
wood  appears  to  be  generated,  pass  immediately  from  the  leaf-stalk 
towards  the  root ;  and  though  the  motion  of  this  fluid  may  be  impeded 
by  gravitation,  and  it  be  even  again  returned  into  the  leaf,  no  portion  of 
it,  unless  it  had  been  extravasated,  could  have  descended  to  the  part 
from  which  the  bark  was  taken  off  in  the  experiment  I  have  described. 
I  am  not  sensible  that  in  the  different  papers  which  I  have  had  the 
honour  to  address  to  you,  I  have  drawn  any  other  inference  which 
the  facts,  on  repetition  of  the  experiments,  do  not  appear  capable  of 
supporting. 

*  See  above,  No.  III.  f  See  the  preceding  Papers. 


124 


VII.— ON  THE  DIRECTION  OF  THE  RADICLE    AND   GERMEN  DURING  THE 
VEGETATION  OF  SEEDS. 

[Read  before  the  ROYAL  SOCIETY,  January  9,  1006.] 

IT  can  scarcely  have  escaped  the  notice  of  the  most  inattentive  observer 
of  vegetation,  that  in  whatever  position  a  seed  is  placed  to  germinate,  its 
radicle  invariably  makes  an  effort  to  descend  towards  the  centre  of  the 
earth,  whilst  the  elongated  germen  takes  a  precisely  opposite  direction  ; 
and  it  has  been  proved  by  Duhamel  *  that  if  a  seed,  during  its  germina- 
tion, be  frequently  inverted,  the  points  both  of  the  radicle  and  germen 
will  return  to  the  first  direction.  Some  naturalists  have  supposed  these 
opposite  effects  to  be  produced  by  gravitation  ;  and  it  is  not  difficult  to 
conceive  that  the  same  agent,  by  operating  on  bodies  so  differently  orga- 
nised as  the  radicle  and  germen  of  plants  are,  may  occasion  the  one  to 
descend  and  the  other  to  ascend. 

The  hypothesis  of  these  naturalists  does  not,  however,  appear  to  have 
been  much  strengthened  by  any  facts  they  were  able  to  adduce  in  support 
of  it,  nor  much  weakened  by  the  arguments  of  their  opponents ;  and 
therefore,  as  the  phenomena  observable  during  the  conversion  of  a  seed 
into  a  plant  are  amongst  the  most  interesting  that  occur  in  vegetation, 
I  commenced  the  experiments,  an  account  of  which  I  have  now  the 
honour  to  request  you  to  lay  before  the  Royal  Society. 

I  conceived  that  if  gravitation  were  the  cause  of  the  descent  of  the 
radicle,  and  of  the  ascent  of  the  germen,  it  must  act  either  by  its  imme- 
diate influence  on  the  vegetable  fibres  and  vessels  during  their  formation, 
or  on  the  motion  and  consequent  distribution  of  the  true  sap  afforded  by 
the  cotyledons :  and  as  gravitation  could  produce  these  effects  only 
whilst  the  seed  remained  at  rest,  and  in  the  same  position  relative  to  the 
attraction  of  the  earth,  I  imagined  that  its  operation  would  become 
suspended  by  constant  and  rapid  change  of  the  position  of  the  germi- 
nating seed,  and  that  it  might  be  counteracted  by  the  agency  of  centri- 
fugal force. 

Having  a  strong  rill  of  water  passing  through  my  garden,  I  con- 
structed a  small  wheel  similar  to  those  used  for  grinding  corn,  adapting 
another  wheel  of  a  different  construction,  and  formed  of  very  slender 
pieces  of  wood,  to  the  same  axis.  Round  the  circumference  of  the 
latter,  which  was  eleven  inches  in  diameter,  numerous  seeds  of  the 
garden  bean,  which  had  been  soaked  in  water  to  produce  their  greatest 
degree  of  expansion,  were  bound,  at  short  distances  from  each  other. 

*  Physique  des  Arbres. 


ON    THE    DIRECTION    OF    THE    RADICLE    AND    GERMEN,    ETC.  125 

The  radicles  of  these  seeds  were  made  to  point  in  every  direction,  some 
towards  the  centre  of  the  wheel,  and  others  in  the  opposite  direction ; 
others  as  tangents  to  its  curve,  some  pointing  backwards,  and  others 
forwards,  relative  to  its  motion ;  and  others  pointing  in  opposite  direc- 
tions in  lines  parallel  with  the  axis  of  the  wheels.  The  whole  was 
inclosed  in  a  box,  and  secured  by  a  lock,  and  a  wire  grate  was  placed 
to  prevent  the  ingress  of  any  body  capable  of  impeding  the  motion  of 
the  wheels. 

The  water  being  then  admitted,  the  wheels  performed  something  more 
than  150  revolutions  in  a  minute;  and  the  position  of  the  seeds  relative 
to  the  earth  was  of  course  as  often  perfectly  inverted,  within  the  same 
period  of  time ;  by  which  I  conceive  that  the  influence  of  gravitation 
must  have  been  wholly  suspended. 

In  a  few  days  the  seeds  began  to  germinate,  and  as  the  truth  of  some 
of  the  opinions  I  had  communicated  to  you,  and  of  many  others  which  I 
had  long  entertained,  depended  on  the  result  of  the  experiment,  I 
watched  its  progress,  with  some  anxiety,  though  not  with  much  appre- 
hension ;  and  I  had  soon  the  pleasure  to  see  that  the  radicles,  in  what- 
ever direction  they  were  protruded  from  the  position  of  the  seed,  turned 
their  points  outwards  from  the  circumference  of  the  wheel,  and  in  their 
subsequent  growth  receded  nearly  at  right  angles  from  its  axis.  The 
germens,  on  the  contrary,  took  the  opposite  direction,  and  in  a  few  days 
their  points  all  met  in  the  centre  wheel.  Three  of  these  plants  were  suf- 
fered to  remain  on  the  wheel,  and  were  secured  to  its  spokes  to  prevent 
their  being  shaken  off  by  its  motion.  The  stems  of  these  plants  soon 
extended  beyond  the  centre  of  the  wheel :  but  the  same  cause,  which 
first  occasioned  them  to  approach  its  axis,  still  operating,  their  points 
returned  and  met  again  at  its  centre. 

The  motion  of  the  wheel  being  in  this  experiment  vertical,  the  radicle 
and  germen  of  every  seed  occupied,  during  a  minute  portion  of  time  in 
each  revolution,  precisely  the  same  position  they  would  have  assumed  had 
the  seeds  vegetated  at  rest ;  and  as  gravitation  and  centrifugal  force  also 
acted  in  lines  parallel  with  the  vertical  motion  and  surface  of  the  wheel, 
I  conceived  that  some  slight  objections  might  be  urged  against  the  con- 
clusions I  felt  inclined  to  draw.  I  therefore  added  to  the  machinery  I 
have  described  another  wheel,  which  moved  horizontally  over  the  vertical 
wheels  ;  and  to  this,  by  means  of  multiplying  wheels  of  different  powers, 
I  was  enabled  to  give  many  different  degrees  of  velocity.  Round  the  cir- 
cumference of  the  horizontal  wheel,  whose  diameter  was  also  eleven  inches, 
seeds  of  the  bean  were  bound  as  in  the  experiment  which  I  have  already 


126  ON    THE    DIRECTION    OF    THE    RADICLE 

described,  and  it  was  then  made  to  perform  250  revolutions  in  a  minute. 
By  the  rapid  motion  of  the  water-wheel  much  water  was  thrown  upwards 
on  the  horizontal  wheel,  part  of  which  supplied  the  seeds  upon  it  with 
moisture,  and  the  remainder  was  dispersed,  in  a  light  and  constant 
shower,  over  the  seeds  in  the  vertical  wheel,  and  on  others  placed  to  vege- 
tate at  rest  in  different  parts  of  the  box. 

Every  seed  on  the  horizontal  wheel,  though  moving  with  great  rapidity, 
necessarily  retained  the  same  position  relative  to  the  attraction  of  the 
earth  ;  and  therefore  the  operation  of  gravitation  could  not  be  suspended, 
though  it  might  be  counteracted,  in  a  very  considerable  degree,  by  con- 
trifugal  force  :  and  the  difference,  I  had  anticipated,  between  the  effects 
of  rapid  vertical  and  horizontal  motion  soon  became  sufficiently  obvious. 
The  radicles  pointed  downwards  about  ten  degrees  below,  and  the  ger- 
mens  as  many  degrees  above,  the  horizontal  line  of  the  wheel's  motion ; 
centrifugal  force  having  made  both  to  deviate  80°  from  the  perpendicular 
direction  each  would  have  taken,  had  it  vegetated  at  rest.  Gradually 
diminishing  the  rapidity  of  the  motion  of  the  horizontal  wheel,  the 
radicles  descended  more  perpendicularly,  and  the  germens  grew  more 
upright ;  and  when  it  did  not  perform  more  than  eighty  revolutions  in  a 
minute,  the  radicle  pointed  about  45°  below,  and  the  germen  as  much 
above,  the  horizontal  line,  the  one  always  receding  from,  and  the  other 
approaching  to,  the  axis  of  the  wheel. 

I  would  not,  however,  be  understood  to  assert  that  the  velocity  of  250, 
or  of  eighty  horizontal  revolutions  in  a  minute,  will  always  give  accurately 
the  degrees  of  depression  and  elevation  of  the  radicle  and  germen  which 
I  have  mentioned  ;  for  the  rapidity  of  the  motion  of  my  wheels  was  some- 
times diminished  by  the  collection  of  fibres  of  conferva  against  the  wire 
grate  ;  which  obstructed  in  some  degree  the  passage  of  the  water :  and 
the  machinery,  having  been  the  workmanship  of  myself  and  my  gardener, 
cannot  be  supposed  to  have  moved  with  all  the  regularity  it  might  have 
done,  had  it  been  made  by  a  professional  mechanic.  But  I  conceive 
myself  to  have  fully  proved  that  the  radicles  of  germinating  seeds  are 
made  to  descend,  and  their  germens  to  ascend,  by  some  external  cause, 
and  not  by  any  power  inherent  in  vegetable  life  :  and  I  see  little  reason  to 
doubt  that  gravitation  is  the  principal,  if  not  the  only  agent  employed,  in 
this  case,  by  nature.  I  shall  therefore  endeavour  to  point  out  the  means 
by  which  I  conceive  the  same  agent  may  produce  effects  so  diametrically 
opposite  to  each  other. 

The  radicle  of  a  germinating  seed  (as  many  naturalists  have  observed) 
is  increased  in  length  only  by  new  parts  successively  added  to  its  apex  or 


AND    GERMEN    DURING    VEGETATION.  127 

point,  and  not  at  all  by  any  general  extension  of  parts  already  formed  : 
and  the  new  matter  which  is  thus  successively  added  unquestionably 
descends  in  a  fluid  state  from  the  cotyledons*.  On  this  fluid,  and  on  the 
vegetable  fibres  and  vessels  whilst  soft  and  flexible,  and  whilst  the  matter 
which  composes  them  is  changing  from  a  fluid  to  a  solid  state,  gravita- 
tion, I  conceive,  would  operate  sufficiently  to  give  an  inclination  down- 
wards to  the  point  of  the  radicle  ;  and  as  the  radicle  has  been  proved  to 
be  obedient  to  centrifugal  force,  it  can  scarcely  be  contended  that  its 
direction  would  remain  uninfluenced  by  gravitation. 

I  have  stated  that  the  radicle  is  increased  in  length  only  by  parts 
successively  added  to  its  point :  the  germen,  on  the  contrary,  elongates 
by  a  general  extension  of  its  parts  previously  organised  ;  and  Its  vessels 
and  fibres  appear  to  extend  themselves  in  proportion  to  the  quantity  of 
nutriment  they  receive.  If  the  motion  and  consequent  distribution  of 
the  true  sap  be  influenced  by  gravitation,  it  follows,  that  when  the  germen 
at  its  first  emission,  or  subsequently,  deviates  from  a  perpendicular  direc- 
tion, the  sap  must  accumulate  on  its  under  side  :  and  I  have  found  in  a 
great  variety  of  experiments  on  the  seeds  of  the  horse-chestnut,  the  bean, 
and  other  plants,  when  vegetating  at  rest,  that  the  vessels  and  fibres  on 
the  under  side  of  the  germen  invariably  elongate  much  more  rapidly  than 
those  on  its  upper  side ;  and  thence  it  follows  that  the  point  of  the 
germen  must  always  turn  upwards.  And  it  has  been  proved  that  a 
similar  increase  of  growth  takes  place  on  the  external  side  of  the  germen 
when  the  sap  is  impelled  there  by  centrifugal  force,  as  it  is  attracted  by 
gravitation  to  its  under  side,  when  the  seed  germinates  at  rest. 

This  increased  elongation  of  the  fibres  and  vessels  of  the  under  side  is 
not  confined  to  the  germens,  nor  even  to  the  annual  shoots  of  trees,  but 
occurs  and  produces  the  most  extensive  effects  in  the  subsequent  growth 
of  their  trunks  and  branches.  The  immediate  effect  of  gravitation  is 
certainly  to  occasion  the  further  depression  of  every  branch,  which  extends 
horizontally  from  the  trunk  of  the  tree ;  and,  when  a  young  tree  inclines 
to  either  side,  to  increase  that  inclination :  but  it  at  the  same  time 
attracts  the  sap  to  the  under  side,  and  thus  occasions  an  increased  longi- 
tudinal extension  of  the  substance  of  the  new  wood  on  that  side  f .  The 
depression  of  the  lateral  branch  is  thus  prevented  ;  and  it  is  even  enabled 
to  raise  itself  above  its  natural  level,  when  the  branches  above  it  are 
removed  ;  and  the  young  tree,  by  the  same  means,  becomes  more  upright, 

*  See  the  preceding  Paper. 

f  This  effect  does  not  appear  to  be  produced  in  what  are  called  weeping  trees  ;  the  cause  of 
which  I  have  endeavoured  to  point  out  in  a  former  memoir.  (See  above,  No.  IV.) 


128  ON    THE    DIRECTION    OF    THE    RADICLE 

in  direct  opposition  to  the  immediate  action  of  gravitation  :  nature,  as 
usual,  executing  the  most  important  operations  by  the  most  simple  means. 

I  could  adduce  many  more  facts  in  support  of  the  preceding  deductions, 
but  those  I  have  stated,  I  conceive  to  be  sufficiently  conclusive.  It  has 
however  been  objected  by  Duhamel,  (and  the  greatest  deference  is 
always  due  to  his  opinions,)  that  gravitation  could  have  little  influence 
on  the  direction  of  the  germen,  were  it  in  the  first  instance  protruded,  or 
were  it  subsequently  inverted,  and  made  to  point  perpendicularly  down- 
wards. To  enable  myself  to  answer  this  objection,  I  made  many  experi- 
ments on  seeds  of  the  horse-chestnut,  and  of  the  bean,  in  the  box  I  have 
already  described ;  and  as  the  seeds  there  were  suspended  out  of  the 
earth,  I  could  regularly  watch  the  progress  of  every  effort  made  by  the 
radicle  and  germen  to  change  their  positions.  The  extremity  of  the 
radicle  of  the  bean,  when  made  to  point  perpendicularly  upwards,  gene- 
rally formed  a  considerable  curvature  within  three  or  four  hours,  when 
the  weather  was  warm.  The  germen  was  more  sluggish ;  but  it  rarely 
or  never  failed  to  change  its  direction  in  the  course  of  twenty-four  hours ; 
and  all  my  efforts  to  make  it  grow  downwards,  by  slightly  changing  its 
direction,  were  invariably  abortive. 

Another,  and  apparently  a  more  weighty,  objection  to  the  preceding 
hypothesis,  (if  applied  to  the  subsequent  growth  and  forms  of  trees,) 
arises  from  the  facts  that  few  of  their  branches  rise  perpendicularly 
upwards,  and  that  their  roots  always  spread  horizontally  ;  but  this 
objection  I  think  may  be  readily  answered. 

The  luxuriant  shoots  of  trees,  which  abound  in  sap,  in  whatever 
direction  they  are  first  protruded,  almost  uniformly  turn  upwards,  and 
endeavour  to  acquire  a  perpendicular  direction ;  and  to  this  their  points 
will  immediately  return,  if  they  are  bent  downwards  during  any  period 
of  their  growth ;  their  curvature  upwards  being  occasioned  by  an 
increased  extension  of  the  fibres  and  vessels  of  their  under  sides,  as  in 
the  elongated  germens  of  seeds.  The  more  feeble  and  slender  shoots  of 
the  same  trees  will,  on  the  contrary,  grow  in  almost  every  direction, 
probably  because  their  fibres,  being  more  dry,  and  their  vessels  less 
amply  supplied  with  sap,  they  are  less  affected  by  gravitation.  Their 
points,  however,  generally  show  an  inclination  to  turn  upwards ;  but  the 
operation  of  light,  in  this  case,  has  been  proved  by  Bonnet  *  to  be  very 
considerable. 

The  radicle  tapers  rapidly,  as  it  descends  into  the  earth,  and  its  lower 
part  is  much  compressed  by  the  greater  solidity  of  the  mould  into  which 

*  Rccherches  sur  l'Us;ige  des  Feuilles  dans  les  Plantes. 


AND    GERMEN    DURING    VEGETATION.  129 

it  penetrates.  The  true  sap  also  continues  to  descend  from  the  cotyle- 
dons and  leaves,  and  occasions  a  continued  increase  of  the  growth  of 
the  upper  parts  of  the  radicle,  and  this  growth  is  subsequently  aug- 
mented by  the  effects  of  motion,  when  the  germen  has  risen  above  the 
ground.  The  true  sap  is  therefore  necessarily  obstructed  in  its  descent ; 
numerous  lateral  roots  are  generated,  into  which  a  portion  of  the 
descending  sap  enters.  The  substance  of  these  roots,  like  that  of  the 
slender  horizontal  branches,  is  much  less  succulent  than  that  of  the 
radicle  first  emitted,  and  they  are  in  consequence  less  obedient  to  gravi- 
tation :  and  therefore,  meeting  less  resistance  from  the  superficial  soil 
than  from  that  beneath  it,  they  extend  horizontally  in  every  direction, 
growing  with  most  rapidity,  and  producing  the  greatest  number  of  rami- 
fications, wherever  they  find  most  warmth,  and  a  soil  best  adapted  to 
nourish  the  tree.  As  these  horizontal,  or  lateral  roots  surround  the 
base  of  the  tree  on  every  side,  the  true  sap  descending  down  its  bark, 
enters  almost  exclusively  into  them,  and  the  first  perpendicular  root, 
having  executed  its  office  of  securing  moisture  to  the  plant,  whilst  young, 
is  thus  deprived  of  proper  nutriment,  and,  ceasing  almost  wholly  to  grow, 
becomes  of  no  importance  to  the  tree.  The  tap  root  of  the  oak,  about 
which  so  much  has  been  written,  will  possibly  be  adduced  as  an  excep- 
tion ;  but  having  attentively  examined  at  least  20,000  trees  of  this  spe- 
cies, many  of  which  had  grown  in  some  of  the  deepest  and  most  favour- 
able soils  of  England,  and  never  having  found  a  single  tree  possessing  a 
tap  root,  I  must  be  allowed  to  doubt  that  one  ever  existed. 

As  trees  possess  the  power  to  turn  the  upper  surfaces  of  their  leaves, 
and  the  points  of  their  shoots  to  the  light,  and  their  tendrils  in  any 
direction  to  attach  themselves  to  contiguous  objects,  it  may  be  suspected 
that  their  lateral  roots  are  by  some  means  directed  to  any  soil  in  their 
vicinity  which  is  best  calculated  to  nourish  the  plant,  to  which  they  belong; 
and  it  is  well  known  that  much  the  greater  part  of  the  roots  of  an 
aquatic  plant,  which  has  grown  in  a  dry  soil,  on  the  margin  of  a  lake  or 
river,  have  been  found  to  point  to  the  water ;  whilst  those  of  another 
species  of  tree  which  thrives  best  in  a  dry  soil,  have  been  ascertained  to 
take  an  opposite  direction  :  but  the  result  of  some  experiments  I  have 
made  is  not  favourable  to  this  hypothesis,  and  I  am  rather  inclined  to 
believe  that  the  roots  disperse  themselves  in  every  direction,  and  only 
become  most  numerous  where  they  find  most  employment,  and  a  soil  best 
adapted  to  the  species  of  plant.  My  experiments  have  not,  however, 
been  sufficiently  varied,  or  numerous,  to  decide  this  question,  which  I 
propose  to  make  the  subject  of  future  investigation. 


130 


VIII.— ON  THE  INVERTED  ACTION  OF  THE  ALBURNOUS  VESSELS  OF 

TREES. 

[Read  before  the  ROYAL  SOCIETY,  May  15,  1806.] 

I  HAVE  endeavoured  to  prove,  in  several  memoirs*  laid  before  the 
Royal  Society,  that  the  fluid  by  which  the  various  parts  (that  are  annu- 
ally added  to  trees,  and  herbaceous  plants  whose  organization  is  similar 
to  that  of  trees,)  are  generated,  has  previously  circulated  through  their 
leavesf  either  in  the  same  or  preceding  season,  and  subsequently  de- 
scended through  their  bark  ;  and  after  having  repeated  every  experiment 
that  occurred  to  me,  from  which  I  suspected  an  unfavourable  result,  I  am 
not  in  possession  of  a  single  fact,  which  is  not  perfectly  consistent  with  the 
theory  I  have  advanced. 

There  is,  however,  one  circumstance  stated  by  Hales  and  Duhamel, 
which  appears  to  militate  against  my  hypothesis  ;  and  as  that  circum- 
stance probably  induced  Hales  to  deny  altogether,  the  existence  of 
circulation  in  plants,  and  Duhamel  to  speak  less  decisively  in  favour  of 
it  than  he  possibly  might  otherwise  have  done,  I  am  anxious  to  recon- 
cile the  statements  of  these  great  naturalists,  (which  1  acknowledge 
to  be  perfectly  correct,)  with  the  statements  and  opinions  I  have  on 
former  occasions  communicated  to  you. 

Both  Hales  and  Duhamel  have  proved,  that  when  two  circular 
incisions  through  the  bark,  round  the  stem  of  a  tree,  are  made  at  a 
small  distance  from  each  other,  and  when  the  bark  between  these 
incisions  is  wholly  taken  away,  that  portion  of  the  stem  which  is  below 
the  incisions  through  the  bark  continues  to  live,  and  in  some  degree 
to  increase  in  size,  though  much  more  slowly  than  the  parts  above  the 
incisions.  They  have  also  observed,  that  a  small  elevated  ridge  (bour- 
relet)  is  formed  round  the  lower  lip  of  the  wound  in  the  bark,  which 
makes  some  slight  advances  to  meet  the  bark  and  wood  projected,  in 
much  larger  quantity  from  the  opposite,  or  upper  lip  of  the  wound. 

I  have  endeavoured  in  a  former  memoir J,  to  explain  the  cause  why 
some  portion  of  growth  takes  place  below  incisions  through  the  bark, 

*  See  the  preceding  memoirs,  Nos.  II.  IV.  and  V. 

f  During  the  circulation  of  the  sap  through  the  leaves,  a  transparent  fluid  is  emitted,  in  the 
night,  from  pores  situated  on  their  edges,  and  on  evaporating  this  liquid  obtained  from  very 
uxuriant  plants  of  the  vine  I  found  a  very  large  residuum  to  remain,  which  was  similar  in 
external  appearance  to  carbonate  of  lime.  It  must  however  have  been  a  very  different  substance 
from  the  very  large  portion  which  the  water  held  in  solution.  I  do  not  know  that  this  sub- 
stance has  been  analysed  or  observed  by  any  naturalist. 

I  See  above,  No.  III. 


ON    THE    ACTION    OF    ALBURNOUS    VESSELS.  131 

by  supposing  that  a  small  part  of  the  true  sap,  descending  from  the 
leaves,  escapes  downwards  through  the  porous  substance  of  the  albur- 
num. Several  facts  stated  by  Hales,  seem  favourable  to  this  supposition; 
and  the  existence  of  a  power  in  the  alburnum  to  carry  the  sap  in  differ- 
ent directions,  is  proved  in  the  growth  of  inverted  cuttings  of  different 
species  of  trees*.  But  I  have  derived  so  many  advantages,  both  as 
gardener  and  farmer,  (particularly  in  the  management  of  fruit  and  forest 
trees,)  from  the  experiments  which  have  been  the  subject  of  my  former 
memoirs,  that  I  am  confident  much  public  benefit  might  be  derived 
from  an  intimate  acquaintance  with  the  use  and  office  of  the  various 
organs  of  plants ;  and  thence  feel  anxious  to  adduce  facts  to  prove 
that  the  conclusions  I  have  drawn,  are  not  inconsistent  with  the  facts 
stated  by  my  great  predecessors. 

It  has  been  acknowledged,  I  believe,  by  every  naturalist  who  has 
written  on  the  subject,  (and  the  fact  is  indeed  too  obvious  to  be  contro- 
verted,) that  the  matter  which  enters  into  the  composition  of  the  radicles 
of  germinating  seeds  existed  previously  in  their  cotyledons,  and  as  the 
radicles  increase  only  in  length  by  parts  successively  added  to  their 
apices,  or  points  most  distant  from  their  cotyledons,  it  follows  of  necessity, 
that  the  first  motion  of  the  true  sap,  at  this  period,  is  downwards.  And 
as  no  alburnous  tubes  exist  in  the  radicles  of  germinating  seeds  during 
the  earlier  periods  of  their  growth,  the  sap  in  its  descent,  must  either 
pass  through  the  bark,  or  the  medulla.  But  the  medulla  does  not 
apparently  contain  any  vessels  calculated  to  carry  the  descending  sap ; 
while  the  cortical  vessels  are  during  this  period  much  distended  and  full 
of  moisture  ;  and  as  the  medulla  certainly  does  not  carry  any  fluid  in 
stems  or  branches  of  more  than  one  year  old,  it  can  scarcely  be  suspected 
that  it,  at  any  period,  conveys  the  whole  current  of  the  descending  sap. 

As  the  leaves  grow,  and  enter  on  their  office,  cortical  vessels,  in  every 
respect  apparently  similar  to  those  which  descended  from  the  cotyledons, 
are  found  to  descend  from  the  bases  of  the  leaves ;  and  there  appears 
no  reason  with  which  I  am  acquainted,  to  suspect  that  both  do  not  carry 
a  similar  fluid,  and  that  the  course  of  this  fluid  is,  in  the  first  instance, 
always  towards  the  roots. 

The  ascending  sap,  on  the  contrary,  rises  wholly  through  the  alburnum 
and  central  vessels ;  for  the  destruction  of  a  portion  of  the  bark,  in  a 
circle  round  the  tree,  does  not  immediately,  in  the  slightest  degree  check 
the  growth  of  its  leaves  and  branches  ;  but  the  alburnous  vessels  appear, 
from  the  experiments  I  have  stated  in  a  former  paperf,  and  from  those 

*  See  above,  No.  IV.  f  See  above,  No.  IV. 

K2 


132  ON    THE    INVERTED    ACTION 

I  shall  now  proceed  to  relate,  to  be  also  capable  of  an  inverted  action, 
when  that  becomes  necessary  to  preserve  the  existence  of  the  plant. 

As  soon  as  the  leaves  of  the  oak  were  nearly  full  grown  in  the  last 
spring,  I  selected  in  several  instances,  two  poles  of  the  same  age,  and 
springing  from  the  same  roots  in  a  coppice,  which  had  been  felled  about 
six  years  preceding ;  and  making  two  circular  incisions  at  the  distance 
of  three  inches  from  each  other,  through  the  bark  of  one  of  thejpoles  on 
each  stool,  I  destroyed  the  bark  between  the  incisions,  and  thus  cut  off 
the  communication  between  the  leaves,  and  the  lower  parts  of  the  stem 
and  roots,  through  the  bark.  Much  growth,  as  usual,  took  place  above 
the  space  from  which  the  bark  had  been  taken  off,  and  very  little  below  it. 

Examining  the  state  of  the  experiment  in  the  succeeding  winter,  I 
found  it  had  not  succeeded  according  to  my  hopes  ;  for  a  portion  of  the 
alburnum,  in  almost  every  instance  was  lifeless,  and  almost  dry,  to  a 
considerable  distance  below  the  space  from  which  the  bark  had  been 
removed.  In  one  instance  the  whole  of  it  was,  however,  perfectly  alive ; 
and  in  this  I  found  the  specific  gravity  of  the  wood  above' the  decorti- 
cated space  to  be  1.114,  and  below  it,  1.111  ;  and  the  wood  of  the  un- 
mutilated  pole,  at  the  same  distance  from  the  ground,  to  be  1.112,  each 
being  weighed  as  soon  as  it  was  detached  from  the  root. 

Had  the  true  sap  in  this  instance  wholly  stagnated  above  the  decor- 
ticated space,  the  specific  gravity  of  the  wood  there  ought  to  have  been, 
according  to  the  result  of  former  experiments*,  comparatively  much 
greater ;  but  I  do  not  wish  to  draw  any  conclusion  from  a  single  experi- 
ment ;  and  indeed,  I  see  very  considerable  difficulty  in  obtaining  any 
very  satisfactory,  or  decisive  facts  from  any  experiments  on  plants,  in 
this  case,  in  which  the  same  roots  and  stems  collect  and  convey  the  sap 
during  the  spring  and  summer  ;  and  retain  within  themselves  that  which 
is,  during  the  autumn  and  winter,  reserved  to  form  new  organs  of  assimi- 
lation in  the  succeeding  spring.  In  the  tuberous-rooted  plants,  the  roots 
and  stems  which  collect  and  convey  the  sap  in  one  season,  and  those  in 
which  it  is  deposited  and  reserved  for  the  succeeding  season,  are  per- 
fectly distinct  organs  ;  and  from  one  of  these,  the  potato,  I  obtained 
more  interesting  and  decisive  results. 

My  principal  object  was  to  prove,  that  a  fluid  descends  from  the  leaves 
and  stem,  to  form  the  tuberous  roots  of  this  plant ;  and  that  this  fluid 
will  in  part  escape  down  the  alburnous  substance  of  the  stem,  when  the 
continuity  of  the  cortical  vessel  is  interrupted.  But  I  had  also  another 
object  in  view. 

*  See  above,  No.  V. 


OF    THE    ALBURNOUS    VESSELS    OF    TREES.  133 

Every  gardener  knows  that  early  varieties  of  the  potato  never  afford 
either  blossom  or  seeds  ;  and  I  attributed  this  peculiarity  to  privation  of 
nutriment,  owing  to  the  tubers  being  formed  preternaturally  early,  and 
thence  drawing  off  that  portion  of  the  true  sap  which,  in  the  ordinary 
course  of  nature,  is  employed  in  the  formation  and  nutrition  of  blossoms 
and  seeds. 

I  therefore  planted,  in  the  last  spring,  some  cuttings  of  a  very  early 
variety  of  the  potato,  which  had  never  been  known  to  blossom,  in  garden 
pots,  having  heaped  the  mould  as  high  as  I  could  above  the  level  of  the 
pot,  and  planted  the  portion  of  the  root  nearly  at  the  top  of  it.  When 
the  plants  had  grown  a  few  inches  high,  they  were  secured  to  strong 
sticks,  which  had  been  fixed  erect  in  the  pots  for  that  purpose,  and  the 
mould  was  then  washed  away  from  the  base  of  their  stems  by  a  strong 
current  of  water. 

Each  plant  was  now  suspended  in  air,  and  had  no  communication  with 
the  soil  in  the  pots,  except  by  its  fibrous  roots,  and  .as  these  are  perfectly 
distinct  organs  from  the  runners  which  generate  and  feed  the  tuberous 
roots,  I  could  readily  prevent  the  formation  of  them.  Efforts  were  soon 
made  by  every  plant  to  generate  runners,  and  tuberous  roots  ;  but  these 
were  destroyed  as  soon  as  they  became  perceptible.  An  increased  lux- 
uriance of  growth  now  became  visible  in  every  plant,  numerous  blossoms 
were  emitted,  and  every  blossom  afforded  fruit. 

Conceiving,  however,  that  a  small  portion  only  of  the  true  sap  would 
be  expended  in  the  production  of  blossoms  and  seeds,  I  was  anxious  to 
discover  what  use  nature  would  make  of  that  which  remained  ;  and  I 
therefore  took  effectual  means  to  prevent  the  formation  of  tubers  on  any 
part  of  the  plants,  except  the  extremities  of  the  lateral  branches,  those 
being  the  points  most  distant  from  the  earth,  in  which  the  tubers  are 
naturally  deposited.  After  an  ineffectual  struggle  of  a  few  weeks,  the 
plants  became  perfectly  obedient  to  my  wishes,  and  formed  their  tubers 
precisely  in  the  places  I  had  assigned  them.  Many  of  the  joints  of  the 
plants  during  the  experiment  became  enlarged  and  turgid ;  and  I  am 
much  inclined  to  believe,  that  if  I  had  totally  prevented  the  formation  of 
regular  tubers,  these  joints  would  have  acquired  an  organization  capable 
of  retaining  life,  and  of  affording  plants  in  the  succeeding  spring. 

I  had  another  variety  of  the  potato,  which  grew  with  great  luxuriance, 
and  afforded  many  lateral  branches ;  and  just  at  that  period,  when  I  had 
ascertained  the  first  commencing  formation  of  the  tubers  beneath  the 
soil,  I  nearly  detached  many  of  these  lateral  branches  from  the  principal 
stems,  letting  them  remain  suspended  by  such  a  portion  only  of  alburnous 


134?  ON    THE    INVERTED    ACTION 

and  cortical  fibres  and  vessels  as  were  sufficient  to  preserve  life.  In  this 
position  I  conceived  that  if  their  leaves  and  stems  contained  any  unem- 
ployed true  sap,  it  could  not  readily  find  its  way  to  the  tuberous  roots, 
its  passage  being  obstructed  by  the  rupture  of  the  vessels,  and  by  gravita- 
tion ;  and  I  had  soon  the  pleasure  to  see,  that  instead  of  returning  down 
the  principal  stem  into  the  ground,  it  remained  and  formed  small  tubers 
at  the  base  of  the  leaves  of  the  depending  branches. 

The  preceding  facts  are,  I  think,  sufficient  to  prove  that  the  fluid, 
from  which  the  tuberous  root  of  the  potatoe,  when  growing  beneath  the 
soil,  derives  its  component  matter,  exists  previously  either  in  the  stems 
or  leaves  ;  and  that  it  subsequently  descends  into  the  earth  :  and  as  the 
cortical  vessels  during  every  period  of  the  growth  of  the  tuber  are  filled 
with  the  true  sap  of  the  plant,  and  as  these  vessels  extend  into  the  run- 
ners, which  carry  nutriment  to  the  tuber,  and  in  other  instances  evidently 
convey  the  true  sap  downwards,  there  appears  little  reason  to  doubt  that 
through  these  vessels  the  tuber  is  naturally  fed. 

To  ascertain,  therefore,  whether  the  tubers  would  continue  to  be  fed 
when  the  passage  of  the  true  sap  down  the  cortical  vessels  was  interrupted, 
I  removed  a  portion  of  bark  of  the  width  of  five  lines,  and  extending 
round  the  stems  of  several  plants  of  the  potato,  close  to  the  surface  of 
the  ground,  soon  after  that  period  when  the  tubers  were  first  formed. 
The  plants  continued  some  time  in  health,  and  during  that  period  the 
tubers  continued  to  grow,  deriving  their  nutriment,  as  I  conclude,  from 
the  leaves  by  an  inverted  action  of  the  alburnous  vessels.  The  tubers, 
however,  by  no  means  attained  their  natural  size,  partly  owing  to  the 
declining  health  of  the  plant,  and  partly  to  the  stagnation  of  a  portion  of 
the  true  sap  above  the  decorticated  space. 

The  fluid  contained  in  the  leaf  has  not,  however,  been  proved,  in  any 
of  the  preceding  experiments,  to  pass  downwards  through  the  decorticated 
space,  and  to  be  subsequently  discharged  into  the  bark  below  it ;  but  I 
have  proved  with  amputated  branches  of  different  species  of  trees  that  the 
water  which  their  leaves  absorb,  when  immersed  in  that  fluid,  will  be 
carried  downwards  by  the  alburnum,  and  conveyed  into  a  portion  of  bark 
below  the  decorticated  space ;  and  that  the  insulated  bark  will  be 
preserved  alive  and  moist  during  several  days  *  ;  and  if  the  moisture 
absorbed  by  a  leaf  can  be  thus  transferred,  it  appears  extremely  probable 
that  the  true  sap  will  pass  through  the  same  channel.  This  power  in 
alburnum  to  carry  fluids  in  different  directions  probably  answers  very 

*  This  experiment  does  not  succeed  till  the  leaf  has  attained  its  full  growth  and  maturity 
and  the  alburnum  of  the  annual  shoot  its  perfect  organisation. 


OF    THE    ALBURNOUS    VESSELS    OF    TREES.  135 

important  purposes  in  hot  climates,  where  the  dews  are  abundant,  and 
the  soil  very  dry ;  for  the  moisture  the  dews  afford  may  thus  be  con- 
veyed to  the  extremities  of  the  roots  :  and  Hales  has  proved  that  the 
leaves  absorb  most  when  placed  in  humid  air ;  and  that  the  sap  descends, 
either  through  the  bark  or  alburnum  during  the  night. 

If  the  inverted  action  of  the  alburnous  vessels  in  the  decorticated  space 
be  admitted,  it  is  not  difficult  to  explain  the  cause  why  some  degree  of 
growth  takes  place  below  such  decorticated  spaces  on  the  stems  of  trees ; 
and  why  a  small  portion  of  bark  and  wood  is  generated  on  the  lower  lip 
of  the  wound.  A  considerable  portion  of  the  descending  true  sap 
certainly  stagnates  above  the  wound,  and  of  that  which  escapes  into  the 
bark  below  it,  the  greater  part  is  probably  carried  towards,  and  into,  the 
roots ;  where  it  preserves  life,  and  occasions  some  degree  of  growth  to 
take  place.  But  a  small  portion  of  that  fluid  will  be  carried  upwards  by 
capillary  attraction,  between  the  bark  and  the  alburnum,  exclusive  of  the 
immediate  action  of  the  latter  substance,  and  the  whole  of  this  will  stag- 
nate on  the  lower  lip  of  the  wound ;  where  I  conceive  it  generates  the 
small  portion  of  wood  and  bark,  which  Hales  and  Duhamel  have 
described. 

I  should  scarcely  have  thought  an  account  of  the  preceding  experi- 
ments worth  sending  to  you,  but  that  many  of  the  conclusions  I  have 
drawn  in  former  memoirs  appear,  at  first  view,  almost  incompatible  with 
the  facts  stated  by  Hales  and  Duhamel,  and  that  I  had  one  fact  to  com- 
municate relative  to  the  effects  produced  by  the  stagnation  of  the 
descending  sap  of  resinous  trees,  which  appeared  to  lead  to  important 
consequences.  I  have  in  my  possession  a  piece  of  a  fir-tree,  from  which 
a  portion  of  bark,  extending  round  its  whole  stem,  had  been  taken  off 
several  years  before  the  tree  was  felled  ;  and  of  this  portion  of  wood,  one 
grew  above,  and  the  other  below,  the  decorticated  space.  Conceiving 
that  the  wood  above  the  decorticated  space  ought  to  be  much  heavier 
than  that  below  it,  owing  to  the  stagnation  of  the  descending  sap,  I 
ascertained  the  specific  gravity  of  both  kinds,  taking  a  wedge  of  each  as 
nearly  of  the  same  form,  as  I  could  obtain,  and  I  found  the  difference 
greatly  more  than  I  had  anticipated,  the  specific  gravity  of  the  wood 
above  the  decorticated  space  being  0'590,  and  of  that  below  only  0'491  : 
and  having  steeped  pieces  of  each,  which  weighed  a  hundred  grains, 
during  twelve  hours  in  water,  I  found  the  latter  had  absorbed  69  grains, 
and  the  former  only  51. 

The  increased  solidity  of  the  wood  above  the  decorticated  space,  in 
this  instance,  must,  I  conceive,  have  arisen  from  the  stagnation  of  the 


136  ON    THE    ACTION    OF    THE    ALBURNOUS    VESSELS. 

true  sap  in  its  descent  from  the  leaves  ;  and  therefore  in  felling  firs,  or 
other  resinous  trees,  considerable  advantages  may  be  expected  from 
stripping  off  a  portion  of  their  bark  all  round  their  trunks,  close  to  the 
surface  of  the  ground,  about  the  end  of  May,  or  beginning  of  June,  in 
the  summer  preceding  the  autumn  in  which  they  are  to  be  felled.  For 
much  of  the  resinous  matter  contained  in  the  roots  of  these  is  probably 
carried  up  by  the  ascending  sap  in  the  spring,  and  the  return  of  a  large 
portion  of  this  matter  to  the  roots  would  probably  be  prevented  *  ;  the 
timber,  I  have  however  very  little  doubt,  would  be  much  improved  by 
standing  a  second  year,  and  being  then  felled  in  the  autumn  ;  but  some 
loss  would  be  sustained  owing  to  the  slow  growth  of  the  trees  in  the 
second  summer.  The  alburnum  of  other  trees  might  probably  be  rendered 
more  solid  and  durable  by  the  same  process  ;  but  the  descending  sap  of 
these,  being  of  a  more  fluid  consistence  than  that  of  the  resinous  tribe, 
would  escape  through  the  decorticated  space  into  the  roots  in  much 
larger  quantity. 

It  may  be  suspected  that  the  increased  solidity  of  the  wood  in  the  fir- 
tree  I  have  described  was  confined  to  the  part  adjacent  to  the  decorti- 
cated space  ;  but  it  has  been  long  known  to  gardeners,  that  taking  off  a 
portion  of  bark  round  the  branch  of  a  fruit-tree  occasions  the  production 
of  much  blossom  on  every  part  of  the  branch  in  the  succeeding  season. 
The  blossom  in  this  case  probably  owes  its  existence  to  a  stagnation  of 
the  true  sap  extending  to  the  extremities  of  the  branch  above  the  decor- 
ticated space ;  and  it  may  therefore  be  expected  that  the  alburnous 
matter  of  the  trunk  and  branches  of  a  resinous  tree  will  be  rendered 
more  solid  by  a  similar  operation. 


IX.— ON  THE  FORMATION  OF  THE  BARK  OF  TREES. 

[Read  before  the  ROYAL  SOCIETY,  February  19,  1807.] 

AN  extraordinary  diversity  of  opinion  appears  to  have  prevailed 
among  naturalists,  respecting  the  production  and  subsequent  state  of  the 
bark  of  trees. 

According  to  the  theory  of  Malpighi,  the  cortical  substance,  which  is 

*  The  roots  of  trees,  though  of  much  less  diameter  than  their  trunks  and  branches,  probably 
contain  much  more  alburnum  and  bark,  because  they  are  wholly  without  heart  wood,  and  ex- 
tend to  a  much  greater  length  than  the  branches  ;  and  thence  it  may  be  suspected  that  when 
fir-trees  are  felled,  their  roots  contain  at  least  as  much  resinous  matter,  in  a  fluid  moveable 
state,  as  their  trunks  and  branches ;  though  not  so  much  as  is  contained,  in  a  concrete  state,  in 
the  heart  wood  of  those. 


ON  THE  FORMATION  OF  THE  BARK  OF  TREES.  137 

annually  generated,  derives  its  origin  from  the  older  bark ;  and  the 
interior  part  of  this  new  substance  is  annually  transmuted  into  alburnum, 
or  sap  wood ;  whilst  the  exterior  part,  becoming  dry  and  lifeless,  forms 
the  exterior  covering,  or  cortex. 

The  opinions  of  Grew  do  not  appear  to  differ  much  from  those  of 
Malpighi ;  but  he  conceives  the  interior  bark  to  consist  of  two  distinct 
substances,  one  of  which  becomes  alburnum,  whilst  the  other  remains  in 
the  state  of  bark  :  he,  however,  supposes  the  insertments  in  the  wood, 
the  "•  utriculi"  of  Malpighi,  and  the  "  tissu  cellulaire"  of  Duhamel,  to 
have  originally  existed  in  the  bark. 

Hales  on  the  contrary  contends,  that  the  bark  derives  its  existence 
from  the  alburnum,  and  that  it  does  not  undergo  any  subsequent  trans- 
formation. 

The  discoveries  of  Duhamel  have  thrown  much  light  on  the  subject ; 
but  his  experiments  do  not  afford  any  conclusive  result,  and  some  of  them 
may  be  adduced  in  support  of  either  of  the  preceding  hypotheses  :  and  a 
modern  writer  (Mirbel*)  has  endeavoured  to  combine  and  reconcile,  in 
some  degree,  the  apparently  discordant  theories  of  Malpighi  and  Hales. 
He  contends,  with  Hales,  that  the  alburnum  gives  existence  to  the  new 
layer  of  bark ;  but  that  this  bark  subsequently  changes  into  alburnum, 
though  riot  precisely  in  the  manner  described  by  Malpighi. 

So  much  difference  of  opinion,  amongst  men  so  capable  of  observing, 
sufficiently  evinces  the  difficulty  of  the  subject  they  endeavoured  to 
investigate :  and  in  a  course  of  experiments,  which  has  occupied  more 
than  twenty  years,  I  have  scarcely  felt  myself  prepared,  till  the  present 
time,  even  to  give  an  opinion  respecting  the  manner,  in  which  the  cortical 
substance  is  generated  in  the  ordinary  course  of  its  growth  ;  or  repro- 
duced, when  that,  which  previously  existed,  has  been  taken  off. 

Duhamel  has  shown,  that  the  bark  of  some  species  of  trees  is  readily 
reproduced,  when  the  decorticated  surface  of  the  alburnum  is  secluded 
from  the  air  ;  and  I  have  repeated  similar  experiments  on  the  apple,  the 
sycamore,  and  other  trees,  with  the  same  result;  I  have  also  often 
observed  a  similar  reproduction  of  bark  on  the  surface  of  the  alburnum  of 
the  Wych  elm  (Ulmus  montana)  in  shady  situations,  when  no  covering  what- 
ever was  applied.  A  glareous  fluid,  as  Duhamel  has  stated,  exudes  from 
the  surface  of  the  alburnum  :  this  fluid  appears  to  change  into  a  pulpous 
unorganised  mass  which  subsequently  becomes  organised  and  cellular; 
and  the  matter,  which  enters  into  the  composition  of  this  cellular  sub- 
stance, is  evidently  derived  from  the  alburnum. 

*  Traite  d'  Anatomic  et  de  Physiologic  vegetales. 


138  ON  THE  FORMATION  OF  THE  BARK  OF  TREES. 

These  facts  are  therefore  extremely  favourable  to  the  theory  of  Hales  ; 
but  other  facts  may  be  adduced  which  are  scarcely  consistent  with  that 
theory. 

The  internal  surface  of  pieces  of  bark,  when  detached  from  contact  with 
the  alburnum,  provided  they  remain  united  to  the  tree  at  their  upper 
ends,  much  more  readily  generate  a  new  bark,  than  the  alburnum  does 
under  similar  circumstances  :  a  similar  fluid  exudes  from  the  surfaces  of 
both,  and  the  same  phenomena  are  observable  in  both  cases.  The  cellular 
substance,  however,  which  is  thus  generated,  though  it  presents  every 
external  appearance  of  a  perfect  bark,  is  internally  very  imperfectly 
organised ;  and  the  vessels  which  contain  the  true  sap  in  the  bark,  are 
still  wanting  ;  and  I  have  found,  that  these  may  be  made,  by  appropriate 
management,  to  traverse  the  new  cellular  substance  in  almost  any  direc- 
tion. When  I  cut  off  all  communication  above,  and  on  one  side,  between 
the  old  bark  and  that  substance,  I  observed  that  the  vessels  proceeded 
across  it,  from  the  old  bark  on  the  other  side,  taking  always  in  a  greater 
or  less  degree  an  inclination  downwards  ;  and  when  the  cellular  substance 
remained  united  to  the  bark  at  its  upper  end  only,  the  vessels  descended 
nearly  perpendicularly  down  it ;  but  they  did  not  readily  ascend  into  it, 
when  it  was  connected  with  the  bark  at  its  lower  extremity  only ;  the  result 
of  similar  experiments,  when  made  on  different  species  of  trees,  was,  how- 
ever, subject  to  some  variations. 

Pieces  of  bark  of  the  walnut-tree,  which  were  two  inches  broad,  and 
four  long,  having  been  detached  from  contact  with  the  alburnum,  except 
at  their  upper  ends,  and  covered  with  a  plaster  composed  of  bees-wax 
and  turpentine,  in  some  instances,  and  with  clay  only  in  others,  readily 
generated  the  cellular  substance  of  a  new  bark ;  and  between  that  and 
the  old  detached  bark,  very  nearly  as  much  alburnum  was  deposited  as  in 
other  parts  of  the  tree,  where  the  bark  retained  its  natural  position  ; 
which,  I  think,  affords  very  decisive  evidence  of  the  descent  of  the  sap 
through  the  bark.  Similar  pieces  of  bark,  under  the  same  mode  of  treat- 
ment, but  united  to  the  tree  at  their  lower  ends  only,  did  not  long  remain 
alive,  except  at  their  lower  extremities  ;  and  there  a  very  little  alburnum 
only  was  generated.  Other  pieces  of  bark  of  the  same  dimensions,  which 
were  laterally  united  to  the  tree,  continued  alive  almost  to  their  extre- 
mities ;  and  a  considerable  portion  of  alburnum  was  generated,  particu- 
larly near  their  lower  edges ;  the  sap  appearing  in  its  passage  across  the 
bark  to  have  been  given  a  considerable  inclination  downwards :  probably 
owing  to  an  arrangement  in  the  organisation  of  the  bark,  that  I  have 


ON  THE  FORMATION  OF  THE  BARK  OF  TREES.  139 

noticed  in  a  former   memoir*,   which  renders  it  better   calculated   to 
transmit  the  sap  towards  the  roots  than  in  any  other  direction. 

I  have  in  very  few  instances  been  able  to  make  the  walnut-tree  repro- 
duce its  bark  from  the  alburnum,  though  under  the  same  management  I 
rarely  failed  to  succeed  with  the  sycamore  and  apple-tree.  Pieces  of  the 
bark  of  the  apple-tree  will  also  live,  and  generate  a  small  portion  of 
alburnum,  though  only  attached  to  the  tree  at  their  lower  extremities ; 
probably  owing  to  a  small  part  of  the  true  sap  being  carried  upwards  by 
capillary  attraction,  when  the  proper  action  of  the  cortical  vessels  is 
necessarily  suspended. 

The  preceding  experiments,  and  the  authority  of  Duhamel,  having  per- 
fectly satisfied  me,  that  both  the  alburnum  and  bark  of  trees  are  capable 
of  generating  a  new  bark,  or  at  least  of  transmitting  a  fluid  capable  of 
generating  a  cellular  substance,  to  which  the  bark  in  its  more  perfectly 
organised  state  owes  its  existence,  my  attention  was  directed  to  discover 
the  sources  from  which  this  fluid  is  derived.  Both  the  bark  and  the 
alburnum  of  trees  are  composed  principally  of  two  substances ;  one  of 
which  consists  of  long  tubes,  and  the  other  is  cellular ;  and  the  cellular 
substance  of  the  bark  is  in  contact  with  the  similar  substance  in  the 
alburnum,  and  through  these  I  have  long  suspected  the  true  sap  to  pass 
from  the  vessels  of  the  bark  to  those  of  the  alburnumf.  The  intricate 
mixture  of  the  cellular  and  vascular  substances  long  baffled  my  endeavours 
to  discover  from  which  of  them,  in  the  preceding  cases,  the  sap,  and  con- 
sequently the  new  bark,  proceeded  ;  but  I  was  ultimately  successful. 

The  cellular  substance,  both  in  the  alburnum  and  bark  of  old  pollard 
oaks,  often  exists  in  masses  of  near  a  line  in  width,  and  this  organisation 
was  peculiarly  favourable  to  my  purpose.  I  therefore  repeated  on  the 
trunks  of  trees  of  this  kind  experiments  similar  to  those  above-mentioned 
which  were  made  on  the  walnut-tree. 

Apparently  owing  to  the  small  quantity  of  sap,  which  the  old  pollard 
trees  contained,  their  bark  was  very  imperfectly  reproduced;  but  I 
observed  a  fluid  to  ooze  from  the  cellular  substance,  both  of  the 
bark  and  alburnum ;  and  on  the  surface  of  these  substances  alone, 
in  many  instances,  the  new  bark  was  reproduced  in  small  detached 
pieces. 

I  have  endeavoured  to  prove  in  former  communications*,  that  the  true 
sap  of  trees  acquires  those  properties  which  distinguish  it  from  the  fluid 
recently  absorbed,  by  circulating  through  the  leaf;  and  that  it  descends 

*  See  above,  No.  IV.  f  See  above,  No.  V.  p.  118. 

t  See  above,  Nos.  II.  V.  and  VII. 


140  ON  THE  FORMATION  OF  THE  BARK  OF  TREES. 

down  the  bark,  where  part  of  it  is  employed  in  generating  the  new  sub- 
stances annually  added  to  the  tree ;  and  that  the  remainder,  not  thus 
expended,  passes  into  the  alburnum,  and  there  joins  the  ascending  current 
of  sap.  The  cellular  substance,  both  of  the  bark  and  alburnum,  has  been 
proved,  in  the  preceding  experiments,  to  be  capable  of  affording  the  sap 
a  passage  through  it ;  and  therefore  it  appears  not  very  improbable,  that 
it  executes  an  office  similar  to  that  of  the  anastomosing  vessels  of  the 
animal  economy,  when  the  cellular  surfaces  of  the  bark  and  alburnum  are 
in  contact  with  each  other ;  and,  when  detached,  it  may  be  inferred,  that 
the  passing  fluid  will  exude  from  both  surfaces :  because  almost  all  the 
vessels  of  trees  appear  to  be  capable  of  an  inverted  action  in  giving 
motion  to  the  fluids  which  they  carry. 

As  the  power  of  generating  a  new  bark  appeared  in  the  preceding  cases 
to  exist  alike  in  the  sap  of  the  bark  and  of  the  alburnum,  I  was  anxious 
to  discover  how  far  the  fluid,  which  ascends  through  the  central  vessels  of 
the  succulent  annual  shoot,  is  endued  with  similar  powers.  Having  there- 
fore made  two  circular  incisions  through  the  bark,  round  the  stems  of 
several  annual  shoots  of  the  vine,  as  early  in  the  summer  as  the  alburnum 
within  them  had  acquired  sufficient  maturity  to  perform  its  office  of  carry- 
ing up  the  sap,  I  took  off  the  bark  between  these  incisions  ;  and  I  abraded 
the  surface  of  the  alburnum  to  prevent  a  reproduction  of  it.  The  alburnum 
in  the  decorticated  spaces  soon  became  externally  dry  and  lifeless ;  and 
several  incisions  were  then  made  longitudinally  through  it.  The  incisions 
commenced  a  little  above,  and  extended  below  the  decorticated  spaces,  so 
that,  if  the  sap  of  the  central  vessels  generated  a  cellular  substance  (as  I 
concluded  it  would),  that  substance  might  come  into  contact  and  form  a 
union  with  the  substance  of  the  same  kind  emitted  by  the  bark  above  and 
below. 

The  experiment  succeeded  perfectly,  and  the  cellular  substances  gene- 
rated by  the  central  vessels,  and  the  bark,  soon  united,  and  a  perfect 
vascular  bark  was  subsequently  formed  beneath  the  alburnum,  and 
appeared  perfectly  to  execute  the  office  of  that  which  had  been  taken  off; 
the  medulla  appeared  to  be  wholly  inactive. 

I  have  already  observed,  that  the  vessels,  which  were  generated  in  the 
cellular  substance  on  the  surface  of  the  alburnum  of  the  sycamore  and  the 
apple-tree,  traversed  that  substance  in  almost  every  direction ;  and  the 
same  .thing  appears  to  occur  beneath  the  old  bark,  when  united  to  the 
alburnum.  For  having  attentively  examined,  through  every  part  of  the 
spring  and  summer,  the  formation  of  the  internal  bark,  and  alburnous 
layer  beneath  it,  round  the  basis  of  regenerated  buds,  which  I  had  made 


ON    THE    FORMATION    OF    THE    BARK    OF    TREES.  141 

to  spring  from  smooth  spaces  on  the  roots  and  stems  of  trees,  I  found 
every  appearance  perfectly  consistent  with  the  preceding  observations.  A 
single  shoot  only  was  suffered  to  spring  from  each  root  and  stem,  and 
from  the  base  of  this,  in  every  instance,  the  cortical  vessels  dispersed 
themselves  in  different  directions.  Some  descended  perpendicularly 
downwards,  whilst  others  diverged  on  each  side,  round  the  alburnum, 
with  more  or  less  inclination  downwards,  and  met  on  the  opposite  side  of 
it.  The  same  pulpous  and  cellular  substance  appeared  to  cover  the  sur- 
faces of  the  bark  and  alburnum,  when  in  contact  with  each  other,  as  when 
detached ;  and  through  this  substance  the  ramifications  of  the  vessels  of 
the  new  bark  extended  themselves,  appearing  to  receive  their  direction 
from  the  fluid  sap  which  descended  from  the  bark  of  the  young  shoots, 
and  not  to  be,  in  any  degree,  influenced  in  their  course  by  the  direction 
taken  by  the  cortical  and  alburnous  vessels  of  the  preceding  year. 

Whenever  the  vessels  of  the  bark,  which  proceeded  from  different 
points,  met  each  other,  an  interwoven  texture  was  produced,  and  the 
alburnum  beneath  acquired  a  similar  organisation  :  and  the  same  thing 
occurs,  and  is  productive  of  very  important  effects,  in  the  ordinary  course 
of  the  growth  of  trees.  The  bark  of  the  principal  stem,  and  of  every 
lateral  branch,  contains  very  numerous  vessels,  which  are  charged  with 
the  descending  true  sap  ;  and  at  the  juncture  of  the  lateral  branch  with 
the  stem,  these  vessels  meet  each  other.  A  kind  of  pedestal  of  albur- 
num, the  texture  of  which  is  much  interwoven,  is  in  consequence  formed 
round  the  base  of  the  lateral  branch,  which  thus  becomes  firmly  united 
to  the  tree.  This  pedestal,  though  apparently  a  part  of  the  branch,  de- 
rives a  large  portion  of  the  matter  annually  added  to  it  from  the  cortical 
vessels  of  the  principal  stem ;  and  thence,  in  the  event  of  the  death  of 
the  lateral  branch,  it  always  continues  to  live.  But  it  not  unfrequently 
happens,  that  a  lateral  branch  forms  a  very  acute  angle  with  the  prin- 
cipal stem,  and,  in  this  case,  the  bark  between  them  becomes  compressed 
and  inactive ;  no  pedestal  is  in  consequence  formed,  and  the  attachment 
of  such  a  branch  to  the  stem  becomes  extremely  feeble  and  insecure  *. 

*  The  advantages  which  may  be  obtained  by  pruning  timber  trees  judiciously,  appear  to  be 
very  little  known.  I  have  endeavoured  to  ascertain  the  practicability  of  giving  to  trees  such 
forms  as  will  render  their  timber  more  advantageously  convertible  to  naval  or  other  purposes. 
The  success  of  the  experiments  on  small  trees  has  been  complete,  and  the  results  perfectly  con- 
sistent, in  every  case,  with  the  theory  I  have  endeavoured  to  support  in  former  memoirs  ;  and 
I  am  confident,  that  by  appropriate  management,  the  trunks  and  branches  of  growing  trees  may 
be  moulded  into  the  various  forms  best  adapted  to  the  use  of  the  ship-builder,  and  that  the 
growth  of  the  trees  may  at  the  same  time  be  rendered  considerably  more  rapid,  without  any  ex- 
pense or  temporary  loss  to  the  proprietor. 


142  ON  THE  FORMATION  OF  THE  BARK  OF  TREES. 

Instead  of  the  reproduced  buds  of  the  preceding  experiment,  buds  were 
inserted  in  the  foregoing  summer,  or  attached  by  grafting  in  the  spring ; 
and,  when  these  succeeded,  though  they  were  in  many  instances  taken 
from  trees  of  different  species,  and  even  of  different  genera,  no  sensible 
difference  existed  in  the  vessels,  which  appeared  to  diverge  into  the  bark 
of  the  stock,  from  these  buds  and  from  those  reproduced  in  the  preceding 
experiments. 

It  appears,  therefore,  probable,  that  a  pulpous  organisable  mass  first 
derives  its  matter  either  from  the  bark  or  the  alburnum,  and  that  this 
matter  subsequently  forms  the  new  layer  of  bark ;  for,  if  the  vessels  had 
proceeded,  as  radicles  *,  from  the  inserted  buds,  or  grafts,  such  vessels 
would  have  been,  in  some  degree,  different  from  the  natural  vessels  of 
the  bark  of  the  stocks ;  and  it  does  not  appear  probable,  even  without 
referring  to  the  preceding  facts,  that  vessels  should  be  extended,  in  a  few 
days,  by  parts  successively  added  to  their  extremities,  from  the  leaves  to 
the  extremities  of  the  roots ;  which  are,  in  many  instances,  more  than 
200  feet  distant  from  each  other.  I  am,  therefore,  inclined  to  believe, 
that,  as  the  preceding  facts  seem  to  indicate,  the  matter  which  composes 
the  new  bark  acquires  an  organisation  calculated  to  transmit  the  true 
sap  towards  the  roots,  as  that  fluid  progressively  descends  from  the 
leaves  in  the  spring ;  but  whether  the  matter  which  enters  into  the 
composition  of  the  new  bark,  be  derived  from  the  bark  or  alburnum,  in 
the  ordinary  course  of  the  growth  of  the  tree,  it  will  be  extremely  dim- 
cult  to  ascertain. 

It  is,  however,  no  difficult  task  to  prove,  that  the  bark  does  not,  in  all 
cases,  spring  from  the  alburnum ;  for  many  cases  may  be  adduced  in 
which  it  is  always  generated  previously  to  the  existence  of  the  alburnum 
beneath  it :  but  none,  I  believe,  in  which  the  external  surface  of  the 
alburnum  exists  previously  to  the  bark  in  contact  with  it,  except  when 
the  cortical  substance  has  been  taken  off,  as  in  the  preceding  experiments. 
In  the  radicle  of  germinating  seeds,  the  cortical  vessels  elongate,  and 
new  portions  of  bark  are  successively  added  to  their  points,  many  days 
before  any  alburnous  substance  is  generated  in  them  ;  and  in  the  succu- 
lent annual  shoot  the  formation  of  the  bark  long  precedes  that  of  the 
alburnum.  In  the  radicle  the  sap  appears  also  evidently  to  descend  f 
through  the  cortical  vessels  j,  and  in  the  succulent  annual  shoot  it  as 

*  Darwin's  Phytologia.  f  See  above,  Nos.  V.  and  VII. 

J  I  wish  it  to  be  understood,  that  I  exclude  in  these  remarks,  and  in  those  contained  in  ray 
former  memoirs,  all  trees  of  the  palm  kind,  with  the  organisation  of  which  I  am  almost  wholly 
unacquainted. 


ON  THE  FORMATION  OF  THE  BARK  OF  TREES.  143 

evidently  passes  through  the  central  vessels*,  which  surround  the 
medulla.  In  both  cases  a  cellular  substance,  similar  to  that  which  was 
generated  in  the  preceding  experiments,  is  first  formed,  and  this  cellular 
substance  in  the  same  manner  subsequently  becomes  vascular ;  whence  it 
appears,  that  the  true  sap,  or  blood  of  the  plant,  produces  similar  effects, 
and  passes  through  similar  stages  of  organisation,  when  it  flows  from 
different  sources,  and  that  the  power  of  generating  a  new  bark,  properly 
speaking,  belongs  neither  to  the  bark  nor  alburnum,  but  to  a  fluid  which 
pervades  alike  the  vessels  of  both. 

I  shall,  therefore,  not  attempt  to  decide  on  the  merits  of  the  theory  01 
Malpighi,  or  of  Hales,  respecting  the  reproduction  of  the  interior  bark  ; 
but  I  cannot  by  any  means  admit  the  hypothesis  of  Malpighi  and  other 
naturalists,  relative  to  the  transmutation  of  bark  into  alburnum  ;  and  I 
propose,  in  my  next  communication,  to  state  my  reasons  for  rejecting 
that  hypothesis. 


X.— ON  THE  INCONVERTIBILITY  OF  BARK  INTO  ALBURNUM. 

[Read  before  the  ROYAL  SOCIETY,  Feb.  4,  1808.] 

IN  a  letter  which  I  had  the  honour  to  address  to  you  in  the  end  of  the 
last  year^f",  I  endeavoured  to  prove  that  the  matter  which  composes  the 
bark  of  trees  previously  exists  in  the  cells  both  of  their  bark  and  albur- 
num, in  a  fluid  state,  and  that  this  fluid,  even  when  extravasated,  is 
capable  of  changing  into  a  pulpous  and  cellular,  and  ultimately  a  vascular 
substance ;  the  direction  taken  by  the  vessels  being  apparently  dependent 
on  the  course  which  the  descending  fluid  sap  is  made  to  takej.  The 
object  of  the  present  memoir  is  to  prove,  that  the  bark  thus  formed 
always  remains  in  the  state  of  bark,  and  that  no  part  of  it  is  ever  trans- 
muted into  alburnum,  as  many  very  eminent  naturali&ts  have  believed. 

Having  procured,  by  grafting,  several  trees  of  a  variety  of  the  apple 
and  crab  tree,  the  woods  of  which  were  distinguishable  from  each  other  by 

*  See  above,  No.  V.  Mirbel  has  called  the  tubes,  which  I  call  the  central  vessels,  the 
"  tissu  tubulaire"  of  the  medulla. 

t  See  the  preceding  paper. 

I  I  had  observed  this  circumstance  in  many  successive  seasons  ;  but  I  was  not  by  any  means 
prepared  to  believe  that  such  an  arrangement  could  take  place  in  the  coagulum  afforded  by  an 
extravasated  fluid  ;  and  I  am  indebted  to  Mr.  Carlisle  for  having  pointed  out  to  me  many  circum- 
stances in  the  motion  and  powers  of  the  blood  of  animals,  which  induced  me  to  give  credit  to 
the  accuracy  of  my  observations  ;  and  to  that  gentleman,  and  to  Mr.  Home,  I  have  also  subse- 
quently to  acknowledge  many  obligations. 


144  ON    THE    INCONVERTIBILITY 

their  colours,  I  took  off,  early  in  the  spring,  portions  of  bark  of  equal 
length,  from  branches  of  equal  size,  and  I  transposed  these  pieces  of 
bark,  inclosing  a  part  of  the  stem  of  the  apple  tree  with  a  covering  of 
the  bark  of  the  crab  tree,  which  extended  quite  round  it,  and  applying 
the  bark  of  the  apple  tree  to  the  stem  of  the  crab  tree  in  the  same  man- 
ner. Bandages  were  then  applied  to  keep  the  transposed  bark  and  the 
alburnum  in  contact  with  each  other ;  and  the  air  was  excluded  by  a 
plaster  composed  of  bees-  wax  and  turpentine,  and  with  a  covering  of 
tempered  clay. 

The  interior  surface  of  the  bark  of  the  crab  tree  presented  numerous 
sinuosities,  which  corresponded  with  similar  inequalities  on  the  surface  of 
the  alburnum,  occasioned  by  the  former  existence  of  many  lateral 
branches.  The  interior  surface  of  the  bark  of  the  apple  tree,  as  well  as 
the  external  surface  of  the  alburnum,  was,  on  the  contrary,  perfectly 
smooth  and  even.  A  vital  union  soon  took  place  between  the  transposed 
pieces  of  bark,  and  the  alburnum  and  bark  of  the  trees  to  which  they 
were  applied ;  and  in  the  autumn  it  appeared  evident,  that  a  layer  of 
alburnum  had  been,  in  every  instance,  formed  beneath  the  transposed 
pieces  of  bark,  which  were  then  taken  off. 

Examining  the  organisation  of  the  alburnum,  which  had  been  gene- 
rated beneath  the  transposed  pieces  of  bark  of  the  crab  tree,  and  which 
had  formed  a  perfect  union  with  the  alburnum  of  the  apple  tree,  I  could 
not  discover  any  traces  of  the  sinuosities  I  had  noticed ;  nor  was  the 
uneven  surface  of  the  alburnum  of  the  crab  tree  more  changed  by  the 
smooth  transposed  bark  of  the  apple  tree.  The  newly  generated  albur- 
num, beneath  the  transposed  bark,  appeared  perfectly  similar  to  that  of 
other  parts  of  the  stock,  and  the  direction  of  the  fibres  and  vessels  did 
not  in  any  degree  correspond  with  those  of  the  transposed  bark  * . 

Repeating  this  experiment,  I  scraped  off  the  external  surface  of  the  albur- 
num in  several  spaces,  about  three  lines  in  diameter,  and  in  these  spaces 
no  union  took  place  between  the  transposed  bark  and  the  alburnum  of 
the  stock,  nor  was  there  any  alburnum  deposited  in  the  abraded  spaces ; 
but  the  newly  generated  cortical  and  alburnous  layers  took  a  circular, 
and  rather  elliptical,  course  round  those  spaces,  and  appeared  to  have 
been  generated  by  a  descending  fluid,  which  had  divided  into  two 

*  Duhamel  having  taken  off,  and  immediately  replaced,  similar  pieces  of  the  bark  of  young 
elms,  subsequently  found  that  the  alburnum,  which  was  generated  beneath  such  pieces  of  bark, 
had  not  formed  any  union  with  the  alburnum  of  the  tree  beneath  it.  But  this  great  naturalist 
did  not  employ  ligatures  of  sufficient  power  to  bring  the  bark  and  alburnum  into  close  contact, 
or  the  result  would  have  been  different. 


OF    BARK    INTO    ALBUMEN*.  145 

currents  when  it  came  into  contact  with  the  spaces  from  which  the 
surface  had  been  scraped  off,  and  to  have  united  again  immediately 
beneath  them. 

In  each  of  these  experiments,  a  new  cortical  and  alburnous  layer  was 
evidently  generated,  and  apparently  by  the  same  means  that  similar 
substances  were  generated  beneath  a  plaister  composed  of  bees-wax  and 
turpentine,  in  former  experiments  * ;  and  the  only  obvious  difference  in 
the  result  appears  to  be,  that  the  transposed  and  newly-generated  bark 
formed  a  vital  union  with  each  other :  and  it  is  sufficiently  evident,  that 
if  bark  of  any  kind  was  converted  into  alburnum,  it  must  have  been  that 
newly  generated.  For  it  can  scarcely  be  supposed,  that  the  bark  of  a 
crab-tree  was  transmuted  into  the  alburnum  of  an  apple-tree,  or  that  the 
sinuosities  of  the  bark  of  the  crab-tree  could  have  been  obliterated,  had 
such  transmutation  taken  place.  There  is  not,  however,  anything  in 
the  preceding  cases  calculated  to  prove  that  the  newly-generated  bark 
was  not  converted  into  alburnum  ;  and  the  elaborate  experiments  of 
Duhamel  sufficiently  evince  the  difficulty  of  producing  any  decisive 
evidence  in  this  case :  nevertheless  I  trust  that  I  shall  be  able  to  adduce 
such  facts  as.  in  the  aggregate,  will  be  found  nearly  conclusive. 

Examining  almost  every  day,  during  the  spring  and  summer,  the  pro- 
gressive formation  of  alburnum  in  the  young  shoots  of  an  oak  coppice 
which  had  been  felled  two  years  preceding,  I  was  wholly  unable  to  discover 
anything  like  the  transmutation  of  bark  into  alburnum.  The  commence- 
ment of  the  alburnous  layers  in  the  oak  (Quercus  robur)  is  distinguished 
by  a  circular  row  of  very  large  tubes.  These  tubes  are  of  course  gene- 
rated in  the  spring ;  and  during  their  formation,  I  found  the  substance 
through  which  they  passed  to  be  soft  and  apparently  gelatinous,  and  much 
less  tenacious  and  consistent  than  the  substance  of  the  bark  itself;  and, 
therefore,  if  the  matter  which  gave  existence  to  the  alburnum  previously 
composed  the  bark,  it  must  have  been,  during  its  change  of  character, 
nearly  in  a  state  of  solution  ;  but  it  is  the  transmutation  of  one  organised 
substance  into  the  other,  and  not  the  identity  only  of  the  matter  of  both, 
for  which  the  disciples  of  Malpighi  contend  ;  and  if  the  fibres  and  vessels 
of  the  bark  really  became  those  of  the  alburnum,  a  very  great  degree  of 
similarity  ought  to  be  found  in  the  organisation  of  those  substances.  No 
such  similarity,  however,  exists  ;  and  not  anything  at  all  corresponding 
with  the  circular  row  of  large  tubes  in  the  alburnum  of  the  oak  is  dis- 
coverable in  the  bark  of  that  tree.  These  tubes  are  also  generated  within 
the  interior  surface  of  the  bark,  which  is  well  defined ;  and  during  their 

*  See  the  preceding  Paper. 


146  ON    THE    INCONVERTIBILITY 

formation  the  vessels  of  the  bark  are  distinctly  visible,  as  different  organs; 
and  had  the  one  been  transmuted  into  the  other,  their  progressive  changes 
could  not,  I  think,  possibly  have  escaped  my  observation  :  nor  does  the 
organisation  of  the  bark  in  other  instances  in  any  degree  indicate  tho 
character  of  the  wood  that  is  generated  beneath  it :  the  bark  of  the  wych 
elm  ( Ulmus  montana)  is  extremely  tough  and  fibrous  ;  and  it  is  often 
taken  from  branches  of  six  or  eight  years  old,  to  be  used  instead  of 
cords ;  that  of  the  ash  (Fraxinus  excelsior),  on  the  contrary,  when  taken 
from  branches  of  the  same  age,  breaks  almost  as  readily  in  any  one 
direction  as  in  another,  and  scarcely  presents  a  fibrous  texture  ;  yet  tho 
alburnum  of  these  trees  is  not  very  dissimilar,  and  the  one  is  often  substi- 
tuted for  the  other  in  the  construction  of  agricultural  instruments. 

Mirbel  has  endeavoured  to  account  for  the  dissimilar  organisation  of 
the  bark,  and  of  the  wood  into  which  he  conceives  it  to  be  converted,  by 
supposing  that  the  cellular  substance  of  the  bark  is  always  springing  from 
the  alburnum,  whilst  the  tree  is  growing,  and  that  it  carries  with  it  part 
of  the  tubular  substance  (tissu  tubulaire)  of  the  liber,  or  interior  bark. 
These  parts  of  the  interior  bark,  which  are  thus  removed  from  contact 
with  the  alburnum,  he  conceives  to  constitute  the  external  bark  or  cortex, 
whilst  the  interior  part  of  the  liber  progressively  changes  into  alburnum. 

But  if  this  theory  (which  I  believe  I  have  accurately  stated,  though  I 
am  not  quite  certain  that  I  fully  comprehend  its  author*)  were  well 
founded,  the  texture  of  the  alburnum  must  surely  be  much  more  intricate 
and  interwoven  than  it  is,  and  its  ti  :bes  would  lie  less  accurately  parallel 
with  each  other  than  they  do  :  and  were  the  fibrous  substance  of  the 
bark  progressively  changing  into  alburnum,  the  bark  must  of  necessity  be 
firmly  attached  to  the  alburnum  during  the  spring  and  summer  by  the 
continuity,  and  indeed  identity,  of  the  vessels  and  fibres  of  both  these  sub- 
stances. This,  however,  is  not  in  any  degree  the  case,  and  the  bark  is 
in  those  seasons  very  easily  separated  from  the  alburnum ;  to  which  it 
appears  to  be  attached  by  a  substance  that  is  apparently  rather  gelatinous 
than  fibrous  or  vascular  :  and  the  obvious  fact,  that  the  adhesion  of  the 
cortical  vessels  and  fibres  to  each  other  is  much  more  strong  than  the 
adhesion  of  the  bark  to  the  alburnum,  affords  another  circumstance 
almost  as  inconsistent  with  the  theory  of  Malpighi,  as  with  that  of 
Mirbel. 

Many  of  the  experiments  of  Duhamel  are,  however,  apparently  favour- 
able to  the  theory  of  Malpighi,  respecting  the  conversion  of  bark  into 
alburnum ;  and  Mirbel  has  cited  two,  which  he  appears  to  think  conclu- 

*  Traitc  d' Anatomic  et  de  Physiologic  Vege"tale,  Chap.  iii.  Article  5. 


OF    BARK    IXTO    ALBUMEX.  14-7 

sive*.  In  the  first  of  these,  Duhamel  shows  that  pieces  of  silver  wire, 
inserted  in  the  bark  of  trees,  were  subsequently  found  in  their  alburnum ; 
but  Duhamel  himself  has  shown,  with  his  usual  acuteness  and  candour, 
that  the  evidence  afforded  by  this  experiment  is  extremely  defective ;  and 
he  declares  himself  to  be  uncertain  that  the  pieces  of  wire  did  not,  at  their 
first  insertion,  pass  between  the  bark  and  the  alburnum ;  in  which  case 
they  would  necessarily  have  been  covered  by  every  successive  layer  of 
alburnum,  without  any  transmutation  of  bark  into  that  substance^. 

In  the  second  experiment  cited  by  Mirbel,  Duhamel  has  shown  that 
when  a  bud  of  the  peach-tree,  with  a  piece  of  bark  attached  to  it,  is 
inserted  in  a  plum  stock,  a  layer  of  wood  perfectly  similar  to  that  of  the 
peach-tree  will  be  found,  in  the  succeeding  winter,  beneath  the  inserted 
bark.  The  statement  of  Duhamel  is  perfectly  correct ;  but  the  experi- 
ment does  not  by  any  means  prove  the  conversion  of  bark  into  wood  ;  for 
if  it  be  difficult  to  conceive  (as  he  remarks)  that  an  inserted  piece  of  bark 
can  deposit  a  layer  of  alburnum,  it  is  at  least  as  difficult  to  conceive  how 
the  same  piece  of  bark  can  be  converted  into  a  layer  of  alburnum  of  more 
than  twice  its  own  thickness  (and  the  thickness  of  the  alburnum  deposited 
frequently  exceeds  that  of  the  bark  in  this  proportion),  without  any  per- 
ceptible diminution  of  its  own  proper  substance.  The  probable  operation 
of  the  inserted  bud,  which  is  a  well-organised  plant,  at  the  period  when  it 
becomes  capable  of  being  transposed  with  success,  appears  also,  in  this 
case,  to  have  been  overlooked ;  for  I  found  that  when  I  destroyed  the  buds 
in  the  succeeding  winter,  and  left  the  bark  which  belonged  to  them  unin- 
jured, this  bark  no  longer  possessed  any  power  to  generate  alburnum.  It 
nevertheless  continued  to  live,  though  perfectly  inactive,  till  it  became 
covered  by  the  successive  alburnous  layers  of  the  stock  ;  and  it  was  found 
many  years  afterwards  inclosed  in  the  wood.  It  was,  however,  still  bark, 
though  dry  and  lifeless,  and  did  not  appear  to  have  made  any  progress 
towards  conversion  into  wood. 

In  the  course  of  very  numerous  experiments  which  were  made  to 
ascertain  the  manner  in  which  vessels  are  formed  in  the  reproduced 
barkj,  many  circumstances  came  under  my  observation  which  I  could 
adduce  in  support  of  my  opinion,  that  bark  is  never  transmuted  into 
alburnum ;  but  I  do  not  think  it  necessary  to  trouble  you  with  an  account 
of  them  ;  for  though  much  deference  is  certainly  due  to  the  opinions  of 
those  naturalists  who  have  adopted  the  opposite  theory,  and  to  the  doubts 
of  Duhamel,  I  am  not  acquainted  with  a  single  experiment  which  warrants 

*  Chap.  Hi.  Article  5.  f  Physique  des  Arbres,  Liv.  IV.  chap.  iii. 

J  See  the  last  Paper. 

L  2 


148  ON    THE    INCONVERTIBILITY    OF    BARK    INTO    ALBUMEN. 

the  conclusions  they  have  dra\vn ;  and  I  think  that  were  bark  really 
transmuted  into  alburnum,  its  progressive  changes  could  only  have 
escaped  the  eyes  of  prejudiced  or  inattentive  observers.  In  the  course 
of  the  ensuing  spring,  I  hope  to  address  to  you  some  observations  respect- 
ing the  manner  in  which  the  alburnum  is  generated. 


XL— ON  THE  ORIGIN  AND  OFFICE  OF  THE  ALBURNUM  OF  TREES. 
[Read  before  the  ROYAL  SOCIETY,  June  30,  1808.] 

IN  my  last  communication  I  endeavoured  to  prove  that  the  bark 
of  trees  is  not  subsequently  transmuted  into  alburnum ;  and  if  the 
statements  that  I  have  there  given  be  correct,  they  are,  I  conceive,  deci- 
sive on  the  point  for  which  I  contended :  and  if  the  bark  be  not  converted 
into  alburnum,  the  experiments  of  Duhamel  and  subsequent  naturalists, 
and  those  of  which  I  have  given  an  account  in  former  memoirs,  afford 
sufficient  evidence  that  the  bark  deposits  the  alburnous  matter.  If  the 
succulent  shoot  of  a  horse  chestnut,  or  other  tree,  be  examined  at  suc- 
cessive periods  in  the  spring,  it  will  be  seen  that  the  alburnum  is  depo- 
sited, and  its  tubes  arranged,  in  ridges  beneath  the  cortical  vessels ;  and 
the  number  of  these  ridges,  at  the  base  of  each  leaf,  will  be  found  to 
correspond  accurately  with  the  number  of  apertures  through  which  the 
vessels  pass  from  the  leaf- stalks  into  the  interior  bark,  the  alburnous 
matter  being  apparently  deposited  (as  I  have  endeavoured  to  prove  in 
former  memoirs)  by  a  fluid  which  descends  from  the  leaves,  and  subse- 
quently secretes  through  the  bark*.  I  shall  therefore  venture  to  con- 
clude that  it  is  thus  deposited,  and  shall  proceed  to  inquire  into  the 
origin  and  office  of  the  alburnous  tubes. 

The  position  and  direction  of  these  tubes  have  induced  almost  all 
naturalists  to  consider  them  as  the  passages  through  which  the  sap 
ascends ;  and  at  their  first  formation,  when  the  substance  which  surrounds 
them  is  still  soft  and  succulent,  they  are  always  filled  with  the  fluid,  which 
has  apparently  secreted  from  the  bark.  They  appear  to  be  formed  in 
the  soft  cellular  mass,  which  becomes  the  future  alburnum,  as  recepta- 
cles of  this  fluid,  to  which  they  may  either  afford  a  passage  upwards, 
or  simply  retain  it  as  reservoirs,  till  absorbed,  and  carried  off,  by  the 
surrounding  cellular  substance.  The  former  supposition  is,  at  first  view, 
the  most  probable ;  but  the  latter  is  much  more  consistent  with  the  cir- 
cumstances that  I  shall  proceed  to  state. 

*  See  above,  No.  II. 


ON    THE    ORIGIN    OF    ALBURNUM.  149 

Many  different  hypotheses  have  been  offered  by  naturalists  to  account 
for  the  force  with  which  the  sap  ascends  in  the  spring ;  of  these  hypo- 
theses two  only  appear  in  any  degree  adequate  to  the  effects  produced. 
Saussure,  jun.  supposes  that  the  tubes  contract  as  soon  as  they  have 
received  the  sap  in  the  root,  and  that  this  contraction,  commencing 
in  the  root,  proceeds  upwards,  impelling  the  sap  before  it  :  and  I  have 
suggested  that  the  expansion  and  contraction  of  the  compressed  cellular, 
or  laminated  substance  (the  tissu  cellulaire  of  Duhamel  and  Mirbel) 
which  expands  and  contracts  with  change  of  temperature*  after  the  tree 
has  ceased  to  live,  might  produce  similar  effects  by  occasioning  nearly  a 
similar  motion  and  compression  of  the  tubes,  the  coats  of  which  are, 
I  believe,  universally  admitted  not  to  be  membranous.  But  both  these 
hypotheses  are  inconsistent  with  the  facts  that  I  have  now  the  pleasure  to 
communicate  to  you. 

Selecting  parts  of  the  stems  of  young  trees  from  which  annual  branches 
had  sprung  in  the  preceding  year,  I  ascertained,  by  injecting  coloured 
infusions  into  the  stems  through  the  annual  shoots,  that  the  tubes  which 
descended  from  the  latter,  were,  at  their  bases,  confined  to  that  side  of 
the  stem  from  which  they  sprang,  and  to  the  external  annual  layer  of 
wood.  Deep  incisions  were  then  made  into  the  stems  of  other  trees 
immediately  beneath  the  bases  of  similar  annual  shoots,  by  which  I  am 
quite  confident  that  all  communication  through  the  alburnous  tubes,  with 
the  stem,  was  wholly  cut  off;  yet  the  sap  passed  into  the  annual  shoots 
in  the  succeeding  spring,  all  of  which  lived,  and  some  grew  with  consider- 
able vigour.  I,  at  the  same  time,  selected  many  lateral  branches,1' about 
three  lines  in  diameter,  in  a  nursery  of  apple  trees,  which  I  could  ^easily 
secure  to  the  stems  of  the  adjoining  trees  to  prevent  their  being  broken. 
I  then  made  an  incision,  more  than  two  lines  deep  in  each,  on  one  side, 
and  at  the  distance  of  six  or  seven  lines  another  incision,  equally  deep,  on 
the  opposite  side ;  and  as  I  am  quite  certain,  from  the  texture  of  these 
branches,  that  the  alburnous  tubes  passed  straight  through  them,  I  am 
equally  certain  that  every  alburnous  tube  was  at  least  once  intersected. 
Yet  the  sap  passed  into  these  branches,  and  their  buds  unfolded  in 
the  succeeding  spring,  the  incisions  having  been  made  in  the  winter. 
But  I  have  repeated  the  same  experiment  after  the  leaves  have  been 
full-grown  in  the  summer,  and  still  the  branches  have  continued*  to 
live. 

All  naturalists  have  agreed  in  stating  that  trees  perspire  most  in 
the  summer,  when  their  leaves  have  attained  their  full  growth,  and  of 

*  See  above,  p.  92. 


150  ONT    THE    ORIGIN    AND    OFFICE 

course  that  much  sap  must  ascend  at  this  period ;  yet  at  this  period 
the  tubes  of  the  alburnum  appear  dry,  and  to  contain  air  only  ;  which 
induced  Grew  to  suppose  that  the  sap  rose  in  the  state  of  vapour ;  a 
supposition  by  no  means  admissible.  Yet  it  is,  I  conceive,  evident  that 
the  sap  cannot  rise,  as  a  liquid,  through  dry  tubes,  nor  in  any  state 
through  intersected  tubes  ;  and  therefore  it  appears  probable  that  it  does 
not  rise  at  all  through  the  tubes  of  the  alburnum,  and  that  those  tubes 
are  intended  to  execute  a  different  office. 

If  the  sap  do  not  rise  through  the  tubes  of  the  alburnum,  it  must 
rise  through  the  cellular  substance ;  yet  the  passage  of  any  fluid  through 
this  has  been  denied  by  almost  every  naturalist,  probably  because 
coloured  infusions  have  not  been  observed  to  penetrate  it,  and  because 
many  naturalists  have  considered  it  as  mere  compressed  medulla.  Mirbel, 
however,  contends  that  the  fluid  which  generates  the  new  bark  exudes 
from  it;  and  although  a  fluid  capable  of  producing  the  same  effects 
exudes  from  the  bark  when  detached  from  the  alburnum,  I  am  much 
disposed  to  coincide  with  him  in  opinion,  having  observed  a  new  bark  to 
be  generated  on  the  surface  of  the  cellular  substance  of  pollard  oaks, 
in  detached  spaces*.  And  if  the  sap  in  sufficient  quantity  to  generate 
a  new  bark  can  pass  through  the  cellular  substance  of  an  oak,  it  appears 
possible  at  least  that  the  whole  of  the  sap  may  ascend  through  it.  Co- 
loured infusions  do  not,  I  think,  in  any  degree,  pass  through  the  bark  of 
trees,  yet  it  is  evident  that  the  sap  passes  readily  through  it ;  and  there- 
fore, should  it  be  proved  that  such  infusions  do  not  penetrate  the  cellular 
substance  of  the  alburnum,  the  evidence  which  this  circumstance  would 
afford  would  be  very  defective. 

Amongst  other  experiments  that  I  made  to  ascertain  whether  the 
cellular  substance  of  the  alburnum  would  imbibe  coloured  infusions,  I 
took  off  branches  of  two  years  old  with  the  annual  shoots  and  leaves 
attached  to  them,  in  the  summer,  from  trees  of  different  species ;  and 
I  effectually  closed  the  alburnous  tubes  with  a  composition  formed  of 
calcined  oyster  shells  and  cheeset ;  and  this  was  covered  with  a  mixture 
of  bees-wax  and  turpentine,  so  as  to  effectually  exclude  all  moisture. 
A  part  of  the  bark  was  taken  off  each  branch,  in  a  circle  round  it,  a 
few  lines  distant  from  its  lower  end,  where  the  tubes  had  been  closed  ; 
and  each  branch  was  then  placed  in  a  decoction  of  logwood,  in  a  vessel 

*  See  above,  p.  139. 

f  I  have  found  this  composition,  and  this  only,  to  be  capable  of  instantaneously  stopping  the 
effusion  of  sap  from  the  vine,  or  other  tree,  in  the  bleeding  season. 


OP  THE  ALBURNUM  OF  TREES.  151 

deep  enough  to  cover  the  decorticated  spaces.  At  the  end  of  twenty 
hours,  or  somewhat  longer  periods,  these  branches  were  examined,  and 
the  coloured  infusion  was  found  to  have  insinuated  itself  between  the 
alburnous  tubes,  in  many  instances  apparently  through  the  cellular  sub- 
stance. This  was  most  obvious  in  the  walnut-tree,  the  young  wood  of 
which  is  very  white.  The  principal  object  1  had  in  view  in  making  this 
experiment,  was  to  detect  the  passages  through  which  I  conceived  the 
sap  to  pass  from  the  bark  into  the  alburnum*. 

From  the  preceding  circumstances,  I  am  disposed  to  infer  that  the  sap 
secretes  through  the  cellular  substance  of  the  alburnum ;  and  through 
this  I  conceived  that  it  must  ascend  when  the  tubes  were  intersected  in 
the  preceding  experiments,  and  in  those  seasons  of  the  year  when  the 
alburnous  tubes  are  empty,  though  the  sap  must  be  rising  with  great 
rapidity :  and  I  shall  endeavour  to  show  that  the  presence  of  the  sap  m 
the  alburnous  tubes,  during  that  part  of  the  year  in  which  trees,  when 
wounded,  bleed  abundantly,  does  not  afford  any  decisive  evidence  of  the 
ascent  of  the  sap  through  those  tubes. 

In  the  last  spring,  when  the  buds  of  the  sycamore  first  began  to  pre- 
pare for  unfolding,  I  found  that  the  sap  abounded  in  the  points  at  the 
annual  branches ;  and  at  the  same  time  it  flowed  abundantly  from 
incisions  made  into  the  alburnum  near  the  root.  But  when  similar 
incisions  were  made  at  the  distance  of  eight  or  ten  feet  from  the  ground, 
not  the  least  moisture  flowed ;  and  the  tubes  of  the  alburnum  appeared 
to  contain  air  only.  1  also  observed  that  the  sap  flowed  as  abundantly 
from  the  upper  as  from  the  under  side  of  the  lower  incisions,  if  not  more 
abundantly,  and  so  it  continued  to  flow  to  the  end  of  the  bleeding 
season. 

The  sap  must  therefore  have  been,  by  some  means,  thrown  into  the 
tubes  above  the  incisions,  for  the  quantity  discharged  from  them  exceeded 
more  than  a  hundred  times  that  which  the  tubes  could  have  contained  at 
the  time  the  incisions  were  made,  even  had  every  tube  been  filled  to  the 
extremity  of  the  most  distant  branch.  And,  as  it  has  been  shown  that 
the  sap  can  pass  up  when  all  the  alburnous  tubes  are  intersected,  there 
appears,  I  think,  sufficient  evidence  that  it  must  in  this  case  have  been 
raised  by  some  other  agent  than  those  tubes. 

Through  the  cellular  substance  I  therefore  venture  to  conclude  that 
the  sap  ascends ;  and  it  is  not,  I  think,  difficult  to  conceive  that  this  sub- 
stance may  give* the  impulse  with  which  the  sap  is  known  to  ascend  in 
the  spring.  I  have  shown  that  the  bark  more  readily  transmits  the 

*  See  above,  p.  139. 


152  ON    THE    ORIGIN    AND    OFFICE 

descending  sap  towards  the  roots  than  towards  the  points  of  the 
branches  *  ;  and  if  the  cellular  substance  of  the  alburnum  expand  and 
contract,  and  be  so  organised  as  to  permit  the  sap  to  escape  more  easily 
upwards  from  one  cell  to  another  than  in  any  other  direction,  it  will  be 
readily  impelled  to  the  extremities  of  the  branches  :  and  I  have  shown 
that  the  statement,  so  often  repeated  in  the  writings  of  naturalists,  of  a 
power  in  the  alburnum  to  transmit  the  sap  with  equal  facility  in  opposite 
directions,  and  as  well  through  inverted  cuttings  as  others,  is  totally 
erroneous  j-. 

If  the  sap  be  raised  in  the  manner  I  have  suggested,  much  of  it  will 
probably  accumulate  in  the  alburnum  in  the  spring ;  because  the  powers 
of  vegetable  life  are,  at  that  period,  more  active  than  at  any  other  season, 
and  the  leaves  are  not  then  prepared  to  throw  off  any  part  of  it  by  trans- 
piration. And  the  cellular  substance,  being  then  filled,  may  discharge  a 
part  of  its  contents  into  the  alburnous  tubes,  which  again  become  reser- 
voirs, and  are  filled  to  a  greater  or  less  height,  in  proportion  to  the 
vigour  of  the  tree,  and  the  state  of  the  soil  and  season :  and  if  the  tubes 
which  are  thus  filled  be  divided,  the  sap  will  flow  out  of  them,  and  the 
tree  will  be  said  to  bleed.  But  as  soon  as  the  leaves  are  unfolded,  and 
begin  to  execute  their  office,  the  sap  will  be  drawn  from  its  reservoirs, 
and  the  tree  will  cease  to  bleed,  if  wounded. 

The  alburnous  tubes  appear  to  answer  another  purpose  in  trees,  and  to 
be  analogous,  in  some  degree,  in  their  effects,  to  the  cavities  in  the  bones 
of  animals ;  by  which  any  degree  of  strength  that  is  necessary,  is  given 
with  less  expenditure  of  materials,  or  the  incumbrance  of  unnecessary 
weight ;  and  the  wood  of  many  different  species  of  trees  is  thus  made,  at 
the  same  time,  very  light,  and  very  strong,  the  rigid  vegetable  fibres 
being  placed  at  greater  distances  from  each  other  by  the  intervention  of 
alburnous  tubes,  and  consequently  acting  with  greater  mechanical  advan- 
tage, than  they  would  if  placed  immediately  in  contact  with  each  other. 

I  have  shown  in  a  former  communication,  that  the  specific  gravity  of 
the  sap  increases  during  its  ascent  in  the  spring,  and  that  saccharine 
matter  is  generated,  which  did  not  previously  exist  in  the  alburnum,  nor 
in  the  sap,  as  it  rose  from  the  root :  and  I  conceive  it  not  to  be  impro- 
bable, that  the  air  contained  in  the  alburnous  tubes  may  be  instrumental 
in  the  generation  of  this  saccharine  matter.  For  I  discovered  in  the 
last  autumn,  that  much  air  is  absorbed,  or  at  least  disappears,  during 
the  process  of  grinding  apples  for  the  purpose  of  making  cider,  and  that 
during  this  absorption  of  air,  the  juice  of  acid  apples  becomes  very  sweet. 
See  above,  No.  IV.  t  Ibid. 


OF  THE  ALBURNUM  OF  TREES.  153 

and  acquires  many  degrees  of  increased  specific  gravity ;  and  a  similar 
absorption  of  air,  with  corresponding  effects,  is  well  known  to  take  place 
in  the  process  of  malting. 

I  shall  conclude  with  observing,  that  in  retracting  the  opinion  I  for- 
merly entertained  respecting  the  ascent  of  the  sap  in  the  alburnous  tubes, 
I  do  not  mean  to  retract  any  opinion  that  I  have  given  in  former  commu- 
nications respecting  the  subsequent  motion  of  the  sap  through  the  central 
vessels,  the  leaves,  and  bark  ;  or  the  subsequent  junction  of  the  descend- 
ing with  the  ascending  current  in  the  alburnum :  every  experiment  that 
I  have  made  has,  on  the  contrary,  tended  to  confirm  my  former  con- 
clusions. 


XII. —ON    THE    ORIGIN    AND    FORMATION    OF    ROOTS. 
[Read  before  the  ROYAL  SOCIETY,  February,  23,  1809.] 

IN  a  former  communication  I  have  given  an  account  of  some  experi- 
ments, which  induced  me  to  conclude  that  the  buds  of  trees  invariably 
spring  from  their  alburnum,  to  which  they  are  always  connected  by 
central  vessels  of  greater  or  less  length  ;  and  in  the  course  of  much  sub- 
sequent experience,  I  have  not  found  any  reason  to  change  the  opinion 
that  I  have  there  given*.  The  object  of  the  present  communication  is 
to  show,  that  the  roots  of  trees  are  always  generated  by  the  vessels 
which  pass  from  the  cotyledons  of  the  seed,  and  from  the  leaves,  through 
the  leaf-stalks  and  the  bark, -and  that  they  never,  under  any  circum- 
stances, spring  immediately  from  the  alburnum. 

The  organ  which  naturalists  have  called  the  radicle  in  the  seed,  is 
generally  supposed  to  be  analogous  to  the  root  of  the  plant,  and  to 
become  a  perfect  root  during  germination ;  and  1  do  not  know  that  this 
opinion  has  ever  been  controverted,  though  I  believe  that,  when  closely 
investigated,  it  will  prove  to  be  founded  in  error. 

A  root,  in  all  cases  with  which  I  am  acquainted,  elongates  only  by  new 
parts  which  are  successively  added  to  its  apex  or  point,  and  never,  like 
the  stem  or  branch,  by  the  extension  of  parts  previously  organised  ;  and 
I  have  endeavoured  to  show,  in  a  former  memoir,  that  owing  to  this  dif- 
ference in  the  mode  of  the  growth  of  the  root  and  lengthened  plumule  of 
germinating  seeds,  the  one  must  ever  be  obedient  to  gravitation,  and 
point  towards  the  centre  of  the  earth,  whilst  the  other  must  take  the 
opposite  direction  t.  But  the  radicle  of  germinating  seeds  elongates  by 

*  Sec  above,  No.  VI.  f  Ibid.  No.  VII. 


154  ON    THE    ORIGIN 

the  extension  of  parts  previously  organised,  and  in  a  great  number  of 
cases,  which  must  be  familiar  to  every  person's  observation,  raises  the 
cotyledons  out  of  the  mould  in  which  the  seed  is  placed  to  vegetate. 
The  mode  of  growth  of  the  radicle  is  therefore  similar  to  that  of  the  sub- 
stance which  occupies  the  spaces  between  the  buds  near  the  point  of  the 
succulent  annual  shoot,  and  totally  different  from  that  of  the  proper  root 
of  the  plant,  which  I  conceive  to  come  first  into  existence  during  the  ger- 
mination of  the  seed,  and  to  spring  from  the  point  of  what  is  called  the 
radicle.  At  this  period,  neither  the  radicle  nor  cotyledons  contain  any 
alburnum,  and  therefore  the  first  root  cannot  originate  from  that  sub- 
stance ;  but  the  cortical  vessels  are  then  filled  up  with  sap,  and  appa- 
rently in  full  action,  and  through  these  the  sap  appears  to  descend  which 
gives  existence  to  the  true  root. 

When  first  emitted,  the  root  consists  only  of  a  cellular  substance, 
similar  to  that  of  the  bark  of  other  parts  of  the  future  tree ;  and  within 
this  the  cortical  vessels  are  subsequently  generated  in  a  circle,  inclosing 
within  it  a  small  portion  of  the  cellular  substance,  which  forms  the  pith 
or  medulla  of  the  root.  The  cortical  vessels  soon  enter  on  their  office  of 
generating  alburnous  matter ;  and  a  transverse  section  of  the  root  then 
shows  the  alburnum  arranged  in  the  form  of  wedges  round  the  medulla, 
as  it  is  subsequently  deposited  on  the  central  vessels  of  the  succulent 
annual  shoot,  and  on  the  surface  of  the  alburnum  of  the  stems  and 
branches  of  older  trees  *. 

If  a  leaf-stalk  be  deeply  wounded,  a  cellular  substance,  similar  to  that 
of  the  bark  and  young  root,  is  protruded  from  the  upper  lip  of  the  wound, 
but  never  from  the  lower  ;  and  the  leaf-stalks  of  many  plants  possess  the 
power  of  emitting  roots,  which  power  cannot  have  resided  in  alburnum, 
for  the  leaf-stalk  does  not  contain  any ;  but  vessels,  similar  to  those  of 
the  bark  and  radicle,  abound  in  it,  and  apparently  convey  the  returning 
sap  ;  and  from  these  vessels,  or  perhaps  more  properly  from  the  fluid 
they  convey,  the  roots  emitted  by  the  leaf-stalk  derive  their  existence  •(• . 

If  a  portion  of  the  bark  of  a  vine,  or  other  tree,  which  readily  emits 
roots,  be  taken  off  in  a  circle  extending  round  its  stem,  so  as  to 
intercept  entirely  the  passage  of  any  fluid  through  the  bark,  and  any 
body  which  contains  much  moisture  be  applied,  numerous  roots  will  soon 
be  emitted  into  it  immediately  above  the  decorticated  space,  but  never 
immediately  beneath  it :  and  when  the  alburnum  in  the  decorticated 
spaces  has  become  lifeless  to  a  considerable  depth,  buds  are  usually  pro- 
truded beneath,  but  never  immediately  above  it,  apparently  owing  to  the 
I.*  See  above,  No.  II.  Plate  4.  f  Ibid.  No.  II. 


AND    FORMATION    OF    ROOTS.  155 

obstruction  of  the  ascending  sap.  The  roots  which  are  emitted  in  the 
preceding  case  do  not  appear  in  any  degree  to  differ  from  those  which 
descend  from  the  radicles  of  generating  seeds,  and  both  apparently 
derive  their  matter  from  the  fluid  which  descends  through  the  cortical 
vessels. 

There  are  several  varieties  of  the  apple-tree,  the  trunks  and  branches 
of  which  are  almost  covered  with  rough  excrescences,  formed  by  con- 
geries of  points  which  would  have  become  roots  under  favourable  circum- 
stances; and  such  varieties  are  always  very  readily  propagated  by  cuttings. 
Having  thus  obtained  a  considerable  number  of  plants  of  one  of  these 
varieties,  the  excrescences  began  to  form  upon  their  stems  when  two 
years  old,  and  mould  being  then  applied  to  them  in  the  spring,  numerous 
roots  were  emitted  into  it  early  in  the  summer.  The  mould  was  at  the 
same  time  raised  around,  and  applied  to,  the  stems  of  other  trees  of  the 
same  age  and  variety,  and  in  every  respect  similar,  except  that  the  tops 
of  the  latter  were  cut  off  a  short  distance  above  the  lowest  excrescence, 
so  that  there  \vas  no  buds  or  leaves  from  which  sap  could  descend  to 
generate  or  feed  new  roots ;  and  under  these  circumstances  no  roots, 
but  numerous  buds  were  emitted,  and  these  buds  all  sprang  from  the 
spaces  and  points,  which  under  different  circumstances  had  afforded 
roots.  The  tops  of  the  trees  last  mentioned,  having  been  divided  into 
pieces  of  ten  inches  long,  were  planted  as  cuttings,  and  roots  were  by 
these  emitted  from  the  lowest  excrescences  beneath  the  soil,  and  buds 
from  the  uppermost  of  those  above  it. 

I  had  anticipated  the  result  of  each  of  the  preceding  experiments  ;  not 
that  I  supposed,  or  now  suppose,  that  roots  can  be  changed  into  buds,  or 
buds  into  roots  ;  but  I  had  before  proved  that  the  organisation  of  the 
alburnum  is  better  calculated  to  carry  the  sap  it  contains,  from  the  root 
upward,  than  in  any  other  direction,  and  I  concluded  that  the  sap  when 
arrived  at  the  top  of  the  cutting  through  the  alburnum  would  be  there 
employed,  as  I  had  observed  in  many  similar  cases,  in  generating  buds,  and 
that  these  buds  would  be  protruded  where  the  bark  was  young  and  thin, 
and  consequently  afforded  little  resistance  *.  I  had  also  proved  the  bark 
to  be  better  calculated  to  carry  the  sap  towards  the  roots  than  in  the 
opposite  direction,  and  I  thence  inferred  that  as  soon  as  any  buds, 
emitted  by  the  cuttings,  afforded  leaves,  the  sap  would  be  conveyed  from 
these  to  the  lower  extremity  of  the  cuttings  by  the  cortical  vessels,  and 
be  there  employed  in  the  formation  of  roots  f. 

Both  the  alburnum  and  bark  of  trees  evidently  contain  their  true  sap ; 

*  See  above,  No.  VI. 


156  ON    THE    ORIGIN 

but  whether  the  fluid  which  ascends  in  such  cases  as  the  preceding  through 
the  alburnum,  to  generate  buds,  be  essentially  different  from  that  which 
descends  down  the  bark  to  generate  roots,  it  is  perhaps  impossible  to 
decide.  As  nature,  however,  appears  in  the  vegetable  world  to  operate 
by  the  simplest  means ;  and  as  the  vegetable  sap,  like  the  animal  blood, 
is  probably  filled  with  particles  which  are  endued  with  life  ;  were  I  to  offer 
a  conjecture,  I  am  much  more  disposed  to  believe  that  the  same  fluid, 
even  by  merely  acquiring  different  motions,  may  generate  different  organs, 
than  that  two  distinct  fluids  are  employed  to  form  the  root,  and  the  bud 
and  leaf. 

When  alburnum  is  formed  in  the  root,  that  organ  possesses,  in  common 
with  the  stem  and  branches,  the  power  of  producing  buds,  and  of  emitting 
fibrous  roots ;  and  when  it  is  detached  from  the  tree,  the  buds  always 
spring  near  its  upper  end,  and  the  roots  near  the  opposite  extremity,  as 
in  the  cuttings  above  mentioned.  The  alburnum  of  the  root  is  also 
similar  to  that  of  other  parts  of  the  tree,  except  that  it  is  more  porous, 
probably  owing  to  the  presence  of  abundant  moisture  during  the  period 
in  which  it  is  deposited*.  And  possibly  the  same  cause  may  retain  the 
wood  of  the  root  permanently  in  the  state  of  alburnum  ;  for  I  have  shown, 
in  a  former  memoir,  that  if  the  mould  be  taken  away,  so  that  the  parts  of 
the  larger  roots,  which  adjoin  the  trunk,  be  exposed  to  the  air,  such  parts 
are  subsequently  found  to  contain  much  heart  wood*f . 

I  would  wish  the  preceding  observations  to  be  considered  as  extending 
to  trees  only,  and  exclusive  of  the  palm  tribe :  but  I  believe  they  are 
nevertheless  generally  applicable  to  perennial  herbaceous  plants,  and  that 
the  buds  and  fibrous  roots  of  these  originate  from  substances  which  cor- 
respond with  the  alburnum  and  bark  of  trees.  It  is  obvious,  that  the 
roots  which  bulbs  emit  in  the  spring,  are  generated  by  the  sap  which 
descends  from  the  bulb,  when  that  retains  its  natural  position  ;  and  such 
tuberous-rooted  plants  as  the  potato  offer  rather  a  seeming  than  a  real 
obstacle  to  the  hypothesis  I  am  endeavouring  to  establish.  The  buds  of 
these  are  generally  formed  beneath  the  soil ;  but  I  have  shown,  in  a 
former  memoir,  that  the  buds  on  every  part  of  the  stem  may  be  made  to 
generate  tubers,  which  are  similar  to  those  usually  formed  beneath  the 
soil ;  and  I  have  subsequently  seen,  in  many  instances,  such  emitted  by  a 
re-produced  bud,  without  the  calix  of  a  blossom,  which  had  failed  to  pro- 
duce fruit ;  but  I  have  never,  under  any  circumstances,  been  able  to 
obtain  tubers  from  the  fibrous  roots  of  the  plant. 

*  See  above,  No.  VI.  for  1805.  t  Ibid. 


AND    FORMATION    OF    ROOTS.  1 57 

The  tuber  therefore  appears  to  differ  little  from  a  branch,  which  has 
dilated  instead  of  extending  itself,  except  that  it  becomes  capable  of 
retaining  life  during  a  longer  period  ;  and  when  I  have  laboured  through 
a  whole  summer  to  counteract  the  natural  habits  of  the  plant,  a  profusion 
of  blossoms  has  in  many  instances  sprung  from  the  buds  of  a  tuber. 

The  runners  also,  which,  according  to  the  natural  habit  of  the  plant, 
give  existence  to  the  tubers  beneath  the  soil,  are  very  similar  in  organisa- 
tion to  the  stem  of  the  plant,  and  readily  emit  leaves  and  become  con- 
verted into  perfect  stems  in  a  few  days,  if  the  current  of  ascending  sap 
be  diverted  into  them  ;  and  the  mode  in  which  the  tuber  is  formed  above, 
and  beneath  the  soil,  is  precisely  the  same.  And  when  the  sap,  which 
has  been  deposited  at  rest  during  the  autumn  and  winter,  is  again  called 
into  action  to  feed  the  buds,  which  elongate  into  parts  of  the  stems  of 
the  future  plants  in  the  spring,  fibrous  roots  are  emitted  from  the  basis 
of  these  stems,  whilst  buds  are  generated  at  the  opposite  extremities,  as 
in  the  cases  I  have  mentioned  respecting  trees. 

Many  naturalists*  have  supposed  the  fibrous  roots  of  all  plants  to  be  of 
annual  duration  only  ;  and  those  of  bulbous  and  tuberous-rooted  plants 
certainly  are  so  :  as  in  these  nature  has  provided  a  distinct  reservoir  for 
the  sap  which  is  to  form  the  first  leaves  and  fibrous  roots  of  the  succeed- 
ing season ;  but  the  organisation  of  trees  is  very  different,  and  the  albur- 
num and  bark  of  the  roots  and  stems  of  these  are  the  reservoirs  of  their 
sap  during  the  winter^.  When,  however,  the  fibrous  roots  of  trees  are 
crowded  together  in  a  garden-pot,  they  are  often  found  lifeless  in  the 
succeeding  spring ;  but  I  have  not  observed  the  same  mortality  to  occur, 
in  any  degree,  in  the  roots  of  trees  when  growing,  under  favourable  cir- 
cumstances, in  their  natural  situation. 


XIII.— ON    THE    CAUSES   WHICH    INFLUENCE    THE    DIRECTION   OF   THE 

GROWTH  OF  ROOTS. 

[Head  before  the  ROYAL  SOCIETY,  March  7,  1811.] 

I  HAVE  shown,  in  a  former  communication,  the  effects  of  centrifugal 
force  upon  germinating  seeds  ;  from  which  I  have  inferred  that  the  radicles 
are  made  to  descend  towards  the  earth,  and  the  germs,  or  elongated  plu- 
mules, to  take  the  opposite  direction,  by  the  influence  of  gravitation  ;  and 
I  believe  the  facts  I  have  stated  to  be  sufficient  to  support  the  inferences 

*  M.  Mirbel's  Traite  d' Anatomic,  &c.  &c.     Dr.  Smith's  Introduction  to  Botany, 
t  See  above,  No.  V. 


158  ON    TOE    DIRECTION 

I  have  drawn*.  But  the  fibrous  roots  of  plants,  being  much  less  succu- 
lent, though  not  uninfluenced  in  the  directions  they  take  by  gravitation, 
are,  to  a  great  extent,  obedient  to  other  laws,  and  are  generally  found  to 
extend  themselves  most  rapidly,  and  to  the  greatest  length,  in  whatever 
direction  the  soil  is  most  favourable  :  whence  many  naturalists  have  been 
disposed  to  believe  that  these  are  guided  by  some  degrees  of  feeling  and 
perception,  analogous  to  those  of  animal  life. 

I  shall  proceed  to  state  some  of  the  facts  upon  which  this  hypothesis 
has  been  founded,  and  others  which  have  occurred  in  the  course  of  my 
own  experience,  and  which  are  favourable  to  it ;  after  which  I  shall 
endeavour  to  trace  the  effects  observed  to  the  operation  of  different 
causes. 

When  a  tree  which  requires  much  moisture  has  sprung  up,  or  been 
planted,  in  a  dry  soil  in  the  vicinity  of  water,  it  has  been  observed  that 
much  the  largest  portion  of  its  roots  has  been  directed  towards  the  water  ; 
and  that  when  a  tree  of  a  different  species,  and  which  requires  a  dry  soil, 
has  been  placed  in  a  similar  situation,  it  has  appeared,  in  the  direction 
given  to  its  roots,  to  have  avoided  the  water  and  moist  soil. 

A  tree  growing  upon  a  wall,  at  some  distance  from  the  ground,  and 
consequently  ill  supplied  with  food  and  water,  has  also  been  observed  to 
adapt  its  habits  to  its  situation,  and  to  make  very  singular  and  well- 
directed  efforts  to  reach  the  soil  beneath,  by  means  of  its  roots*f.  Dur- 
ing the  period  in  which  it  is  making  such  efforts,  little  addition  is  made  to 
its  branches,  and  almost  the  whole  powers  of  the  plant  appear  to  be 
directed  to  the  growth  of  one  or  more  of  its  principal  roots.  To  these 
much  is  in  consequence  annually  added,  and  they  proceed  perpendicularly 
towards  the  earth,  unless  made  to  deviate  by  some  opposing  body :  and 
as  soon  as  the  roots  have  attached  themselves  to  the  soil,  the  branches 
grow  with  vigour  and  rapidity,  and  the  plant  assumes  the  ordinary  habits 
of  its  species. 

Duhamel  caused  two  trenches  to  be  made  so  as  to  intersect  each  other 
at  right  angles,  and  a  tree  to  be  planted  at  the  point  of  intersection ; 
and  taking  up  this  tree  some  years  afterwards,  he  found  that  the  roots 
had  almost  wholly  confined  themselves  to  the  trenches,  in  which  the  soil 
of  the  former  surface  must  have  been  buried. 

A  trench  which  was  twenty  feet  long,  six  wide,  and  about  two  deep, 
was  prepared  in  my  garden,  in  the  bottom  of  which  trench  was  placed  a 
layer,  about  six  inches  deep,  of  very  rich  mould,  incorporated  with  much 
fresh  vegetable  matter.  This  was  covered,  eighteen  inches  deep,  with 

*  See  above,  No.  VII.  f  Smith's  Introduction  to  Botany. 


OF    THE    GROWTH    OF    ROOTS.  15,9 

light  and  poor  loam,  and  upon  the  bed  thus  formed,  seeds  of  the  common 
carrot  (Daucus  carota)  and  parsnep  (Pastinaca  satlva)  were  sowed. 
The  plants  grew  feebly  till  near  the  end  of  the  summer,  when  they 
assumed  a  very  luxuriant  growth,  grew  .rapidly  till  late  in  the  autumn, 
and  till  their  leaves  were  injured  by  frost.  The  roots  were  then 
examined,  and  were  found  of  an  extraordinary  length,  and  in  form 
almost  perfectly  cylindrical,  having  scarcely  emitted  any  lateral  fibrous 
roots  into  the  poor  soil,  whilst  the  rich  mould  beneath  was  filled  with 
them. 

In  another  experiment  of  the  same  season,  the  preceding  process  was 
reversed,  the  rich  soil  being  placed  upon  the  surface,  and  the  poor 
beneath.  The  plants  here  grew  very  luxuriantly,  and  acquired  a  consider- 
able size  early  in  the  summer ;  and  when  the  roots  were  taken  up  in  the 
autumn,  they  were  found  to  have  assumed  very  different  forms.  The 
greater  part  had  divided  into  two  or  more  unequal  ramifications,  very 
near  the  surface  of  the  ground  ;  and  those  which  were  not  thus  divided 
tapered  rapidly  to  a  point  at  the  surface  of  the  poor  soil,  into  which  few 
of  their  fibrous  roots  had  entered. 

In  other  experiments  seeds  of  almost  all  the  common  esculent  plants 
of  a  garden  were  so  placed  that  the  young  plants  had  an  opportunity  of 
selecting  either  rich  or  poor  soil ;  which  was  disposed,  in  almost  every 
possible  way,  within  their  reach ;  and  I  always  found  abundant  fibrous 
roots  in  the  rich  soil,  and  comparatively  few  in  the  poor. 

The  following  experiment  afforded  the  most  remarkable  result,  and 
one  of  the  least  favourable  to  the  hypothesis  which  I  have  advanced  in  a 
former  paper*,  and  to  the  conclusion  which  I  shall  now  endeavour  to 
support ;  and  therefore  I  think  it  necessary  to  describe  it  very  minutely. 
Some  seeds  of  the  common  bean  (Vicia  faba),  the  plant  with  which 
many  former  experiments  were  made,  were  placed  upon  the  surface  of 
the  mould  in  garden  pots,  in  rows  which  were  about  four  inches  distant 
from  each  other.  A  grate,  formed  of  slender  bars  of  wood,  was  then 
adapted  to  the  surface  of  each  pot,  so  as  to  prevent  both  the  mould  and 
the  seeds  falling  out,  in  whatever  position  the  pots  might  be  placed  ;  and 
the  bars  were  so  disposed  as  not  at  all  to  interfere  with  the  radicles  of 
the  seeds,  when  protruding.  The  pots  were  then  directly  inverted,  and 
the  seeds  were  consequently  placed  beneath  the  mould  ;  but  each  seed 
was  so  far  depressed  into  the  mould  as  to  be  about  half  covered :  by 
which  means  each  radicle,  when  first  emitted,  was  in  contact  with  the 
mould  above,  and  the  air  below.  Water  was  then  introduced  through 

*  See  above,  No.  VII. 


160  ON    THE    DIRECTION 

the  bottom  of  the  inverted  pot,  in  sufficient  quantity  to  keep  the  mould 
moderately  moist ;  and  the  pots  being  suspended  from  the  roof  of  a 
forcing-house,  the  seeds  soon  vegetated. 

In  former  experiments*,  wherever  the  seeds  were  placed  to  vegetate 
at  rest,  the  radicles  descended  perpendicularly  downwards,  in  whatever 
direction  they  were  first  protruded  ;  but  under  the  preceding  circum- 
stances they  extended  horizontally  along  the  surface  of  the  mould,  and  in 
contact  with  it ;  and  in  a  few  days  emitted  many  fibrous  roots  upwards 
into  it :  just  as  they  would  have  done,  if  guided  by  the  instinctive  facul- 
ties and  passions  of  animal  life  ;  and  as  I  concluded  before  I  made  the 
experiment  that  they  would  do,  under  the  guidance  of  much  more  simple 
laws,  whose  mode  of  operating  I  shall  endeavour  to  explain. 

Whatever  be  the  machinery  by  which  the  sap  of  trees  is  raised  to  the 
extremities  of  their  branches,  it  is  obvious  that  this  machinery  is  first 
put  into  action  by  the  stems  and  branches,  and  not  by  the  roots  :  for 
the  graft  or  bud,  whenever  it  has  become  fully  united  to  the  stock,  wholly 
regulates  the  season  and  temperature,  in  which  the  sap  is  to  be  put  in 
motion,  in  perfect  independence  of  the  habits  of  the  stock ;  whether 
those  be  late  or  early.  If  all  the  branches  of  a  tree,  exclusive  of  one, 
be  much  shaded  by  contiguous  trees-f,  or  other  objects,  the  branch  which 
is  exposed  to  the  light  attracts  to  itself  a  large  portion  of  the  ascending 
sap,  which  it  employs  in  the  formation  of  leaves  and  vigorous  annual 
shoots,  whilst  the  shaded  branches  become  languid  and  unhealthy.  The 
motion  of  the  ascending  current  of  sap  appears  therefore  to  be  regulated 
by  the  ability  to  employ  it  in  the  trunk  and  branches  of  the  tree ;  and 
this  current  passes  up  through  the  alburnum,  from  which  substance  the 
buds  and  leaves  spring.  Bat  the  sap  which  gives  existence  to,  and  feeds 
the  root,  descends  through  the  barkj  :  and  if  the  operation  of  light  give 
ability  to  the  exposed  branch  to  attract  and  employ  the  ascending  or 
alburnous  current  of  sap,  it  appears  not  improbable  that  the  operation 
of  proper  food  and  moisture  in  the  soil,  upon  the  bark  of  the  root,  may 
give  ability  to  that  organ  to  attract  and  employ  the  descending,  or  cor- 
tical current  of  sap ;  and  if  this  be  the  case,  an  easy  explanation  of  all 
the  preceding  phenomena  immediately  presents  itself. 

A  tree  growing  upon  a  wall,  and  unconnected  with  the  earth,  will  almost 
of  necessity  grow  slowly,  and  as  it  must  be  scantily  supplied  with  moisture 
during  the  summer,  it  will  rarely  produce  any  other  leaves  than  those 
which  the  buds  contained,  which  were  formed  in  the  preceding  year. 
Some  of  the  roots  of  a  tree,  thus  circumstanced,  will  be  less  well  supplied 

*  See  above,  No.  VII.  f  Ibid.    No.  VI.  and  XII.  I  See  the  last  Paper. 


OF    THE    GROWTH    OF   ROOTS.  161 

\vith  moisture  than  others,  and  these  will  be  first  affected  by  drought : 
their  points  will  in  consequence  become  rigid  and  inexpansible,  and  they 
will  thence  generally  cease  to  elongate  at  an  early  period  of  the  summer. 
The  descending  current  of  sap  will  be  then  employed  in  promoting  the 
growth  and  elongation  of  those  roots  only,  which  are  more  favourably 
situated,  and  which,  comparatively  with  other  parts  of  the  tree,  will  grow 
rapidly.  Gravitation  will  direct  these  roots  perpendicularly  downwards, 
and  the  tree  will  appear  to  have  adopted  the  wisest  and  best  plan  of  con- 
necting itself  with  the  ground :  and  it  will  really  have  employed  the  readiest 
means  of  doing  so,  as  effectively  as  it  could  have  done,  if  it  had  possessed 
all  the  feelings  and  instinctive  passions  and  powers  of  animal  life.  The 
subsequent  vigorous  growth  of  such  a  tree  is  the  natural  consequence  of 
an  improved  and  more  extensive  pasture. 

When  the  seeds  of  the  carrot  and  parsnip,  in  the  experiments  I  have 
stated,  were  placed  in  a  poor  superficial  soil,  but  which  permitted  the 
roots  of  the  plants  to  pass  readily  through  it,  these  were  conducted 
downwards  by  gravitation ;  whilst  the  plants  grew  feebly,  because  they 
received  but  little  nutriment.  The  roots  were  in  a  situation  analogous 
to  that  of  the  stems  of  trees  in  a  crowded  forest ;  and  when  the  leading 
fibres  of  the  roots  came  into  contact  with  the  rich  mould,  they  acquired 
a  situation  correspondent  to  that  of  the  leading  branches  of  such  trees, 
which  are  alone  exposed  to  the  light.  The  form  of  the  roots  of  the  plants 
was  consequently  long,  slender,  and  cylindrical,  like  the  stems  of  such 
trees.  The  roots  of  the  one  required  the  actual  contact  of  proper  soil  and 
nutriment ;  and  the  branches  of  the  other  required  the  actual  contact  of 
light  to  promote  their  growth. 

When,  on  the  contrary,  the  seeds  of  the  preceding  species  of  plants 
were  placed  in  a,  rich  superficial  soil,  their  situation  was  analogous  to  that 
of  a  tree  fully  exposed,  on  every  side,  to  the  light,  whose  branches  would 
be  extended,  in  every  direction,  immediately  above  the  surface  of  the 
ground  :  and  as  the  fibrous  roots  of  the  plants  came  into  contact  with  the 
subsoil,  which  was  not  well  calculated  to  promote  their  growth,  their 
situation  became  analogous  to  that  of  shaded  branches  ;  and  they  conse- 
quently ceased  to  extend  downwards.  The  fibrous  roots  of  a  tree,  under 
similar  circumstances,  would  have  extended  along  the  lower  surface  of 
the  favourable  soil ;  but  after  these  roots  had  much  increased  in  bulk, 
they  would  be  found  partly  compressed  into  the  subsoil,  however  poor 
and  unfavourable,  provided  it  contained  no  ingredients  actually  noxious, 
in  obedience  to  similar  laws,  the  roots  of  an  aquatic  tree  will  not  extend 
freely  in  dry  soil,  nor  those  of  a  tree  which  requires  but  little  moisture 


162  ON    THE    DIRECTION 

in  a  wet  soil ;  and  on  this  account  the  roots  of  the  one  will  appear  to 
have  sought,  and  those  of  the  other  to  have  avoided,  the  contiguous 
water  ;  though  both,  in  the  first  period  of  their  growth,  pointed  their 
roots  alike  in  every  direction. 

When  the  seeds  of  the  bean,  in  the  experiment  I  have  described,  were 
placed  to  vegetate  beneath  the  mould  of  an  inverted  pot,  a  sufficient 
quantity  of  moisture  was  afforded  by  the  mould  to  occasion  the  protrusion 
of  the  radicles  :  but  as  soon  as  the  under  points  of  these  had  penetrated 
through  the  seed-coats,  their  surfaces  were  necessarily  exposed  to  dry  air, 
and  were  consequently  rendered  rigid  and  inexpansible ;  whilst  their 
upper  surfaces,  being  in  contact  with  moist  mould,  remained  soft  and 
expansible.  If  both  the  upper  and  lower  surfaces  of  the  radicles,  at  their 
points,  had  been  equally  well  supplied  with  moisture,  gravitation  would 
have  attracted  the  sap  to  the  lower  sides,  where  new  matter  would  have 
been  added;  and  the  radicles  would  have  extended  perpendicularly 
downwards,  as  in  former  experiments  :  but  the  influence  of  gravitation 
was,  to  a  great  extent,  counteracted  by  the  effects  of  drought  upon  the 
lower  sides  of  the  radicles,  nearly  as  it  was  counteracted  by  centrifugal 
force,  when  made  to  act  horizontally  *. 

As  soon  as  the  radicles  had  acquired  sufficient  age  and  maturity,  efforts 
were  made  by  them  to  emit  fibrous  roots  ;  when  want  of  proper  moisture 
on  the  lower  sides  prevented  their  being  protruded,  in  any  other  direction, 
except  upwards.  In  that  direction  therefore  they  were  alone  emitted, 
(as  I  was  confident  that  they  would  before  I  began  the  experiment)  and 
having  found  proper  food  and  moisture  in  the  pots,  they  extended 
themselves  upwards  through  more  than  half  the  mould,  which  these 
contained. 

This  experiment  was  repeated,  and  water  was  so  constantly  and  abun- 
dantly given,  that  every  part  of  the  radicles  was  kept  equally  wet ;  and 
they  then  became  perfectly  obedient  to  gravitation,  without  being  at  all 
influenced  by  the  mould  above  them. 

In  other  experiments  pieces  of  alum  and  of  the  sulphates  of  iron  and 
copper  were  placed  at  small  distances  perpendicularly  beneath  the  radicles 
of  germinating  seeds,  of  different  species,  to  afford  an  opportunity  of 
observing  whether  any  efforts  would  be  made  by  them  to  avoid  poisons  ; 
but  they  did  not  appear  to  be  at  all  influenced,  except  by  actual  contact 
of  the  injurious  substances.  The  growth  of  their  fibrous  lateral  roots 
was,  however,  obviously  accelerated,  when  their  points  approached  any 
considerable  quantity  of  decomposing  vegetable  or  animal  matter  :  and 

*  Above,  p.  125 


OF    THE    GROWTH    OF    ROOTS.  163 

when  the  growth  of  the  roots  was  retarded  by  want  of  moisture,  the  con- 
tiguity of  water,  in  the  adjoining  mould,  though  not  apparently  in  actual 
contact  with  them,  operated  beneficially :  but  I  had  reason  to  suspect 
that  the  growth  of  roots  was,  under  these  circumstances,  promoted  by 
actual  contact  with  the  detached  and  fugitive  particles  of  the  decomposing 
body,  and  of  the  evaporating  water. 

The  growth  and  forms  assumed  by  the  roots  of  trees,  of  every  species, 
are  to  a  great  extent,  dependent  upon  the  quantity  of  motion,  which  their 
stems  and  branches  receive  from  winds  ;  for  the  effects  of  motion  upon 
the  growth  of  the  root,  and  of  the  trunk  and  branches,  which  I  have 
described  in  a  former  memoir,  are  perfectly  similar*.  Whatever  part  of 
a  root  is  moved  and  bent  by  winds,  or  other  causes,  an  increased  deposi- 
tion of  alburnous  matter  upon  that  part  soon  takes  place,  and  conse- 
quently the  roots  which  immediately  adjoin  the  trunk  of  an  insulated  tree, 
in  an  exposed  situation,  become  strong  and  rigid  ;  whilst  they  diminish 
rapidly  in  bulk,  as  they  recede  from  the  trunk,  and  descend  into  the 
ground.  By  this  sudden  diminution  of  the  bulk  of  the  roots,  the  passage 
of  the  descending  sap,  through  their  bark,  is  obstructed ;  and  it  in  con- 
sequence generates,  and  passes  into  many  lateral  roots  ;  and  these,  if  the 
tree  be  still  much  agitated  by  winds,  assume  a  similar  form,  and  conse- 
quently divide  into  many  others.  A  kind  of  net- work  composed  of  thick 
and  strong  roots  is  thus  formed,  and  the  tree  is  secured  from  the  dangers 
to  which  its  situation  would  otherwise  expose  it. 

In  a  sheltered  valley,  on  the  contrary,  where  a  tree  is  surrounded  and 
protected  by  others,  and  is  rarely  agitated  by  winds,  the  roots  grow  long 
and  slender,  like  the  stem  and  branches,  and  comparatively  much  less  of 
the  circulating  fluid  is  expended  in  the  deposition  of  alburnum  beneath 
the  ground ;  and  hence  it  not  unfrequently  happens,  that  a  tree,  in  the 
most  sheltered  part  of  a  valley,  is  uprooted ;  whilst  the  exposed  and 
insulated  tree,  upon  the  adjoining  mountain,  remains  uninjured  by  the 
fury  of  the  storm. 

In  all  the  preceding  arrangements,  the  wisdom  of  nature,  and  the 
admirable  simplicity  of  the  means  it  employs,  are  conspicuously  displayed ; 
but  I  am  wholly  unable  to  trace  the  existence  of  anything  like  sensation  or 
intellect  in  the  plants  :  and  I  therefore  venture  to  conclude,  that  their  roots 
are  influenced  by  the  immediate  operation  and  contact  of  surrounding 
bodies,  and  not  by  any  degrees  of  sensation  and  passion  analogous  to  those 
of  animal  life  ;  and  I  reject  the  latter  hypothesis,  not  only  because  it  is 
founded  upon  assumptions  which  cannot  be  granted,  but  because  it  is 

*  Above,  p.  £9. 

M2 


I'(j4j  ON    THE    DIRECTION    OF    THE    GROWTH    OF    ROOTS. 

insufficient  to  explain  the  preceding  phenomena,  unless  seedling  plants 
be  admitted  to  possess  more  extensive  intellectual  powers,  than  are  given 
to  the  offspring  of  the  most  acute  animal.  A  young  wild-duck  or  par- 
tridge, when  it  first  sees  the  insect  upon  which  nature  intends  it  to  feed, 
instinctively  pursues  and  catches  it ;  but  nature  has  given  to  the  young 
bird  an  appropriate  organization.  The  plant,  on  the  contrary,  if  it  could 
feel  and  perceive  the  objects  of  its  wants,  and  will  the  possession  of  them, 
has  still  to  contrive  and  form  the  organ  by  which  these  are  to  be  ap- 
proached. The  writers  who  have  contended  for  the  existence  of  sensa- 
tion in  plants,  appear  to  have  been  sensible  of  the  preceding  and  other 
obstacles,  and  have  all  betrayed  the  weakness  of  their  hypothesis,  in 
adducing  a  few  facts  only  which  are  favourable  to  it,  and  waiving  wholly 
the  investigation  of  all  others. 

In  the  description  of  the  preceding  experiments,  I  fear  that  I  have 
been  tediously  minute ;  but  as  I  have  selected  a  few  facts  only  from  a 
great  number,  which  I  could  have  adduced,  I  was  anxious  to  give  as 
accurate  and  distinct  a  view  of  those  I  stated,  as  possible. 


XIV.— ON  THE  MOTIONS  OF  THE  TENDRILS  OF  PLANTS. 
[Read  before  the  ROYAL  SOCIETY,  May  4th,  1812.] 

THE  motions  of  the  tendrils  of  plants,  and  the  efforts  they  apparently 
make  to  approach  and  attach  themselves  to  contiguous  objects,  have 
been  supposed  by  many  naturalists  to  originate  in  some  degrees  of 
sensation  and  perception  :  and  though  other  naturalists  have  rejected 
this  hypothesis,  few,  or  no  experiments  have  been  made  by  them  to 
ascertain  with  what  propriety  the  various  motions  of  tendrils,  of  different 
kinds,  can  be  attributed  to  peculiarity  of  organisation,  and  the  operation 
of  external  causes.  I  was  consequently  induced,  during  the  last  summer, 
to  employ  a  considerable  portion  of  time  to  watch  the  motions  of  the 
tendrils  of  different  species  of  plants  ;  and  I  have  now  the  pleasure  to 
address  to  you  an  account  of  the  observations  I  was  enabled  to  make. 

The  plants  selected  were,  the  Virginia  creeper  (the  Ampelopsis  quin- 
quefolia  of  Michaux,)  the  ivy,  and  the  common  vine  and  pea. 

A  plant  of  the  ampelopsis,  which  grew  in  a  garden  pot,  was  removed 
to  a  forcing-house  in  the  end  of  May,  and  a  single  shoot  from  it  was 
made  to  grow  perpendicularly  upwards,  by  being  supported  in  that 
position  by  a  very  slender  bar  of  wocd,  to  which  it  was  bound.  The 


ON    THE    MOTIONS    OF    THE    TENDRILS    OF    PLANTS.  165 

plant  was  placed  in  the  middle  of  the  house,  and  was  fully  exposed  to 
the  sun  ;  and  every  object  around  it  was  removed  far  beyond  the  reach 
of  its  tendrils.  Thus  circumstanced,  its  tendrils,  as  soon  as  they  were 
nearly  full  grown,  all  pointed  towards  the  north,  or  back  wall,  which  was 
distant  about  eight  feet :  but  not  meeting  with  any  thing  in  that 
direction,  to  which  they  could  attach  themselves,  they  declined  gradually 
towards  the  ground,  and  ultimately  attached  themselves  to  the  stems 
beneath,  and  the  slender  bar  of  wood. 

A.  plant  of  the  same  species  was  placed  at  the  east  end  of  the  house, 
near  the  glass,  and  was  in  some  measure  skreened  from  the  perpendicular 
light ;  when  its  tendrils  pointed  towards  the  west,  or  centre  of  the  house, 
as  those  under  the  preceding  circumstances  had  pointed  towards  the 
north  and  back  wall.  This  plant  was  removed  to  the  west  end  of  the 
house,  and  exposed  to  the  evening  sun,  being  skreened,  as  in  the  pre- 
ceding case,  from  the  perpendicular  light ;  and  its  tendrils,  within  a  few 
hours,  changed  their  direction,  and  again  pointed  to  the  centre  of  the 
house,  which  was  partially  covered  with  vines.  This  plant  was  then 
removed  to  the  centre  of  the  house,  and  fully  exposed  to  the  perpendicular 
light,  and  to  the  sun ;  and  a  piece  of  dark-coloured  paper  was  placed 
upon  one  side  of  it  just  within  the  reach  of  its  tendrils ;  and  to  this 
substance  they  soon  appeared  to  be  strongly  attracted.  The  paper  was 
then  placed  upon  the  opposite  side,  under  similar  circumstances,  and 
there  it  was  soon  followed  by  the  tendrils.  It  was  then  removed,  and  a 
piece  of  plate  glass  was  substituted  ;  but  to  this  substance  the  tendrils 
did  not  indicate  any  disposition  to  approach.  The  position  of  the  glass 
was  then  changed,  and  care  was  taken  to  adjust  its  surface  to  the  varying 
position  of  the  sun,  so  that  the  light  reflected  might  continue  to  strike  the 
tendrils  ;  which  then  receded  from  the  glass,  and  appeared  to  be  strongly 
repulsed  by  it. 

The  tendrils  of  the  ampelopsis  very  closely  resemble  those  of  the  vine, 
in  their  internal  organisation,  and  in  originating  from  the  alburnous 
substance  of  the  plant;  and  in  being,  under  certain  circumstances, 
convertible  into  fruit-stalks.  The  claws,  or  claspers  of  the  ivy,  to 
experiments  upon  which  I  shall  now  proceed,  appear  to  be  cortical 
protrusions  only ;  but  to  be  capable  (I  have  reason  to  believe)  of  becoming 
perfect  roots,  under  favourable  circumstances.  Experiments,  in  every 
respect  very  nearly  similar  to  the  preceding,  were  made  upon  this  plant ;. 
but  I  found  it  necessary  to  place  the  different  substances,  to  which  I 
proposed  that  the  claws  should  attempt  to  attach  themselves,  almost  in. 
contact  with  the  stems  of  the  plants.  I  observed  that  the  claws  of  this 


166  ON    THE    MOTIONS    OF    THE    TEN  OKI  LS    OF    PLANTS. 

plant  evaded  the  light,  just  as  the  tendrils  of  the  ampelopsis  had  done ; 
and  that  they  sprang  only  from  such  parts  of  the  stems  as  were  fully,  or 
partially,  shaded. 

A  seedling  plant  of  the  peach  tree,  and  one  of  the  ampelopsis  and  ivy 
were  placed  nearly  in  the  centre  of  the  house,  and  under  similar  circum- 
stances ;  except  that  supports,  formed  of  very  slender  bars  of  wood, 
about  four  inches  high,  were  applied  to  the  ampelopsis  and  ivy.  The 
peach  tree  continued  to  grow  nearly  perpendicularly,  with  a  slight 
inclination  towards  the  front  and  south  side  of  the  house,  whilst  the  stems 
of  the  ampelopsis  and  ivy,  as  soon  as  they  exceeded  the  height  of  their 
supports,  inclined  many  points  from  the  perpendicular  line,  in  the 
opposite  direction. 

It  appears  therefore  that  not  only  the  tendrils  and  claws  of  these 
creeping  dependent  plants,  but  that  their  stems  also,  are  made  to  recede 
from  light,  and  to  press  against  the  opake  bodies,  which  nature  intended 
to  support  and  protect  them. 

M.  De  Candolle,  I  believe,  first  observed  that  the  succulent  shoots  of 
trees  and  herbaceous  plants,  which  do  not  depend  upon  others  for 
support,  are  bent  towards  the  point  from  which  they  receive  light,  by  the 
contraction  of  the  cellular  substance  of  their  bark  upon  that  side,  and 
I  believe  his  opinion  to  be  perfectly  well  founded.  The  operation  of  light 
upon  the  tendrils  and  stems  of  the  ampelopsis  and  ivy  appears  to  pro- 
duce diametrically  opposite  effects,  and  to  occasion  an  extension  of  the 
cellular  bark,  wherever  that  is  exposed  to  its  influence ;  and  this  circum- 
stance affords,  I  think,  a  satisfactory  explanation  why  these  plants  appear 
to  seek  and  approach  contiguous  opake  objects,  just  as  they  would  do,  if 
they  were  conscious  of  their  own  feebleness,  and  of  power  in  the  objects, 
to  which  they  approach,  to  afford  them  support  and  protection. 

The  tendril  of  the  vine,  as  1  have  already  stated,  is  internally  similar 
to  that  of  the  ampelopsis,  though  its  external  form,  and  mode  of  attach- 
ing itself  by  twining  round  any  slender  body,  are  very  different.  Some 
young  plants  of  this  species,  which  had  been  raised  in  pots  in  the  pre- 
ceding year,  and  had  been  headed  down  to  a  single  bud,  were  placed  in  a 
forcing-house,  with  the  plants  I  have  already  mentioned  ;  and  the  shoots 
from  these  were  bound  to  slender  bars  of  wood,  and  trained  perpen- 
dicularly upwards.  Their  tendrils,  like  those  of  the  ampelopsis,  when 
first  emitted,  pointed  upwards ;  but  they  gradually  formed  an  increasing 
angle  with  the  stems,  and  ultimately  pointed  perpendicularly  downwards ; 
no  object  having  presented  itself  to  which  they  could  attach  themselves. 
Other  plants  of  the  vine,  under  similar  circumstances,  were  trained 


ON    THE    MOTIONS    OF    THE    TENDRILS    OF    PLANTS.  16? 

horizontally;  when  their  tendrils   gradually   descended   beneath   their 
stems,  with  which  they  ultimately  stood  very  nearly  at  right  angles.; 

A  third  set  of  plants  were  trained  almost  perpendicularly  downwards ; 
but  with  an  inclination  of  a  few  degrees  towards  the  north ;  and  the 
tendrils  of  these  permanently  retained  very  nearly  their  first  position, 
relatively  to  their  stems ;  whence  it  appears  that  these  organs,  like  the 
tendrils  of  the  ampelopsis,  and  the  claws  of  the  ivy,  are  to  a  great  extent 
under  the  control  of  light. 

A  few  other  plants  of  the  same  species  were  trained  in  each  of  the  pre- 
ceding methods  ;  but  proper  objects  were  placed,  in  different  situations, 
near  them,  with  w  hich  their  tendrils  might  come  into  contact ;  and  I  was 
by  these  means  afforded  an  opportunity  of  observing,  with  accuracy,  the 
difference  between  the  motions  of  these  and  those  of  the  ampelopsis, 
under  similar  circumstances.  The  latter  almost  immediately  receded 
from  light,  by  whatever  means  that  was  made  to  operate  upon  them;  and 
they  did  not  subsequently  show  any  disposition  to  approach  the  points, 
from  which  they  once  receded.  The  tendrils  of  the  vine,  on  the  contrary, 
varied  their  positions  in  every  period  of  the  day,  and  after  returned 
again  during  the  night  to  the  situations  they  had  occupied  in  the  pre- 
ceding morning ;  and  they  did  not  so  immediately,  or  so  regularly,  bend 
towards  the  shade  of  contiguous  objects.  But  as  the  tendrils  of  this 
plant,  like  those  of  the  ampelopsis,  spring  alternately  from  each  side  of 
the  stem,  and  as  one  point  only  in  three  is  without  a  tendril,  and  as  each 
tendril  separates  into  two  divisions,  they  do  not  often  fail  to  come  into  con- 
tact with  any  object  within  their  reach ;  and  the  effects  of  contact  upon  the 
tendril  are  almost  immediately  visible.  It  is  made  to  bend  towards  the 
body  it  touches,  ^nd  if  that  body  be  slender,  to  attach  itself  firmly  by  twin- 
ing round  it,  in  obedience  to  causes  which  I  shall  endeavour  to  point  out. 

The  tendril  of  the  vine,  in  its  internal  organization,  is  apparently 
similar  to  the  young  succulent  shoot  and  leaf-stalk,  of  the  same  plant ;  and 
it  is  as  abundantly  provided  with  vessels,  or  passages,  for  the  sap  ;  and 
I  have  proved  that  it  is  alike  capable  of  feeding  a  succulent  shoot,  or  a 
leaf,  when  grafted  upon  it.  It  appears  therefore,  I  conceive,  not  impro- 
bable, that  a  considerable  quantity  of  the  moving  fluid  of  the  plant,  passes 
through  its  tendrils  :  and  that  there  is  a  close  connection  between  its 
vascular  structure  and  its  motions. 

I  have  proved  in  the  Philosophical  Transactions  of  1806,  that  centrifu- 
gal force,  by  operating  upon  the  elongating  plumules  of  germinating  seeds, 
occasions  an  increased  growth  and  extension  upon  the  external  sides  of 
the  young  stems,  and  that  gravitation  produces  correspondent  effects ; 


168  ON    THE    MOTIONS    OF    THE    TENDRILS    OF    PLANTS. 

probably  by  ^occasioning  the  presence  of  a  larger  portion  of  the  fluid 
organisable  matter  of  the  plant  upon  the  one  side,  than  upon  the  other. 
The  external  pressure  of  any  body  upon  one  side  of  a  tendril  will  probably 
drive  this  fluid  from  one  side  of  the  tendril,  which  will  consequently 
contract,  to  the  opposite  side,  which  will  expand  ;  and  the  tendril  will 
thence  be  compelled  to  bend  round  a  slender  bar  of  wood  or  metal,  just  as 
the  stems  of  germinating  seeds  are  made  to  bend  upwards,  and  to  raise 
the  cotyledons  out  of  the  ground ;  and  in  support  of  this  conclusion  I 
shall  observe,  that  the  sides  of  the  tendrils,  where  in  contact  with  the 
substance  they  embraced,  were  compressed  and  flattened. 

The  actions  of  the  tendrils  of  the  pea  were  so  perfectly  similar  to  those 
of  the  vine,  when  they  came  into  contact  with  any  body,  that  I  need  not 
trouble  you  with  the  observations  I  made  upon  that  plant.  An  increased 
extension  of  the  cellular  substance  of  the  bark  upon  one  side  of  the 
tendrils,  and  a  correspondent  contraction  upon  the  opposite  side,  occa- 
sioned by  the  operation  of  light,  or  the  partial  pressure  of  a  body  in 
contact,  appeared  in  every  case,  which  has  come  under  my  observation, 
the  obvious  cause  of  the  motions  of  tendrils  ;  and  therefore,  in  conformity 
with  the  conclusions  I  drew  in  my  last  memoir,  respecting  the  growth  of 
roots,  I  shall  venture  to  infer,  that  they  are  the  result  of  pure  necessity 
only,  uninfluenced  by  any  degrees  of  sensation,  or  intellectual  powers. 


XV.— ON  THE  ACTION  OF  DETACHED  LEAVES  OF  PLANTS. 

[Read  before  the  ROYAL  SOCIETY,  June  \3th,  1816.] 

SINCE  I  had  last  the  honour  to  address  a  communication  to  the  Royal 
Society,  I  have  repeated  great  part  of  the  experiments  which  formed  the 
subjects  of  my  former  memoirs,  with  such  additions  and  variations  as 
might  probably  lead  to  the  detection  of  any  erroneous  conclusions  which 
I  might  have  drawn  ;  but  I  have  not  been  able  to  detect  any  errors,  nor  to 
add  anything  very  important  to  my  former  observations.  I  have,  however, 
been  able  to  ascertain  a  few  new  facts,  which  I  think  too  interesting  to 
be  lost. 

I  endeavoured,  in  my  former  communications,  to  adduce  evidence  that 
the  matter,  which  becomes  vitally  united  to  trees,  previously  passes 
through  their  leaves  ;  and  I  shall  now  proceed  to  state  some  facts,  which, 
I  trust,  will  prove  that  a  fluid  possessing  the  power  which  I  have 
attributed  to  the  true  sap  actually  descends  through  the  leaf-stalks. 


ON    THE    ACTION    OF    DETACHED    LEAVES    OF    PLANTS. 


169 


A  slender  knife  was  passed  through  some  leaf-stalks  of  the  vine,  about 
two-thirds  of  an  inch  distant  from  their  junction  to  the  branch ;  and, 
down  to  that  point,  the  leafstalks  were  divided  longitudinally,  and  a 
transverse  section,  about  half-an-inch  long,  was  made  through  the  bark 
opposite  the  middle  of  the  leaf-stalk.  A  similar  transverse  section 
through  the  bark  was  made  somewhat  less  than  an  inch  distant  below ; 
and  these  sections  were  united  by  two  longitudinal  sections  through  the 
bark,  which  extended  from  the  extremities  of  the  upper  transverse 
sections  to  the  extremities  of  the  lower ;  by  which  means  pieces  of  bark, 
about  half-an-inch  broad  and  nearly  an  inch  long,  were  separated  from 
the  adjoining  bark.  These  were  then  detached  from  the  alburnum,  and 
surrounded  by  two  folds  of  paper  coated  with  wax  on  each  side ;  by 
which  all  connexion  and  communication  with  the  tree,  except  through 
the  divided  leaf-stalks,  were  cut  off.  The  insulated  pieces  of  bark, 
nevertheless,  continued  to  grow,  and  extended  downwards,  and  laterally, 
and  in  thickness ;  and  thin  layers  of  alburnum  were  deposited. 

Leaves  of  the  potatoe,  without  any  portion  of  bark  being  attached  to 
them,  were  taken  from  the  plants  just  at  the  period  when  the  tuberous 
roots  began  to  be  formed  ;  and  I  conceived  that  these  leaves,  consistently 
with  my  former  experiments  and  conclusions,  must  contain  portions  of 
the  living  organisable  matter  which  would  subsequently  have  been  found 
in  their  tuberous  roots.  The  leaves  were  therefore  planted  in  pots,  and 
placed  under  glass,  where,  being  regularly  and  properly  supplied  with 
water,  they  continued  to  live  till  winter,  though  without  emitting  fibrous 
roots  ;  and  I  then  expected  to  find  some  small  tubers  at  their  bases.  In 
this  expectation  I  was  disappointed ;  but  the  result  of  the  experiment  was 
not  less  satisfactory,  the  bases  of  the  leaf-stalks  themselves  having  swollen 
into  conic  bodies  of  more  than  two  inches  in  circumference,  and  being 
found  to  consist  of  matter  apparently  similar  to  that  which  composes  the 
tuberous  roots  of  the  plant.  The  enlarged  parts  of  the  leaf-stalks 
remained  alive  in  the  following  spring  ;  but  whether  they  are  capable  of 
generating  buds  or  not  I  have  not  been  able  to  ascertain. 

Leaves  of  mint  were  planted  in  the  same  manner  as  those  above- 
mentioned;  which  grew,  and  continued  alive  through  the  winter,  and 
were  still  living  in  the  end  of  the  last  month,  having  assumed  the  character 
of  the  thick  fleshy  leaves  of  evergreen  trees.  Upon  examining  the  mould 
in  the  pots,  1  found  it  to  contain  very  numerous  roots,  which  must  have 
derived  their  medullary,  and  their  cortical,  and  alburnous  substances, 
from  matter  which  had  emanated  and  descended  from  the  leaves. 

I  had  frequently  observed,  in  former  experiments,  that  the  destruction 


170  ON  THE  ACTION  OF  DETACHED  LEAVES  OF  PLANTS. 

of  the  mature  leaves  of  young  plants  not  only  suspended  the  growth  of 
the  roots,  but  also  the  growth  of  the  immature  leaves  ;  whence  I  inferred, 
in  a  former  communication,  that  the  organisable  matter  which  composes 
the  young  leaves  has  always  undergone  a  previous  preparation  in  other 
leaves  of  the  plant,  either  of  the  same  or  preceding  season  ;  and  I  was 
thence  led  to  expect  that,  under  favourable  circumstances,  the  mature 
leaves  might  be  made  to  nourish  and  promote  the  growth  of  immature 
leaves,  without  the  aid  of  roots.  Several  shoots  of  the  vine,  each  about 
a  yard  long,  were  detached  from  the  trees,  arid  laid  over  a  succession 
of  basins  of  water,  into  which  each  of  the  mature  leaves  was  in  part 
depressed ;  and  thus  circumstanced,  the  young  leaves  continued  to  grow, 
and  the  points  of  the  shoots  to  elongate ;  and  all  were  alive,  and  in 
perfect  apparent  health,  at  the  end  of  a  month.  The  water  necessary  to 
preserve  the  young  leaves  must  in  this  case  have  been  derived  from  the 
mature  leaves  ;  and  I  entertain  no  doubt  but  that  the  organisable  matter 
which  occasioned  their  growth  was  derived  from  the  same  source.  Inter- 
section of  the  bark  between  the  mature  and  young  leaves  was  not  attended 
with  any  injurious  consequences,  and  the  sap  must,  therefore,  have  passed 
to  the  young  leaves  through  the  alburnum. 

Consistently  with  the  preceding  circumstances,  if  the  mature  leaves  be 
destroyed,  or  taken  off,  the  fruit  ceases  to  grow — or,  if  full  grown, 
remains  without  richness  or  flavour ;  and  the  power  of  feeding  fruits  in 
winter  and  early  spring  seems  to  be  confined  to  evergreen  plants.  The 
orange  and  lemon  tree,  the  ivy  and  holly,  afford  familiar  examples  of  this  ; 
and  where  a  genus  of  plants  consists  of  evergreen  and  deciduous  species, 
as  that  of  mespilus  and  viburnum,  the  evergreen  species  alone  nourish 
their  fruit  in  winter  and  early  spring. 

The  probable  passage  of  the  sap  from  the  mature  to  the  young  leaves 
and  fruit  may,  I  think,  be  easily  pointed  out,  though  decisive  proof  of  its 
course  will  probably  never  be  adduced.  Having  often  detached  the  bark 
from  the  alburnum  of  the  stems  of  young  oaks,  just  at  the  period  when 
the  midsummer  shoots  were  beginning  to  elongate,  I  observed,  as  others 
have  done,  that  a  fluid  exuded  from  those  parts  of  the  surface  of  the 
alburnum  which  are  called  (most  improperly)  the  medullary  processes, 
and  from  correspondent  points  of  the  bark  which  resemble  the  medullary 
processes  in  organisation.  This  fluid  has  been  proved,  by  its  power  of 
rapidly  generating  an  organic  substance,  to  be  the  true  sap  of  the  tree ; 
part  of  which,  I  conceive,  at  this  period,  to  be  passing  from  the  bark  to 
join  the  ascending  current  in  the  alburnum ;  which  current  feeds  the 
young  succulent  shoots  and  growing  leaves.  Subjecting  the  alburnum 


ON    THE    ACTION    OF    DETACHED    LEAVES    OF    PLANTS.  171 

to  a  slight  degree  of  pressure  at  this  period,  I  found  that  a  considerable 
quantity  of  liquid,  being  apparently  the  true  sap  of  the  tree,  issued  out 
laterally  through  the  medullary  processes,  as  well  as  longitudinally 
through  the  cellular  substance  of  the  alburnum;  but  the  tubes  of  it 
continued  empty,  and  their  position  was  marked  by  depressions  of  the 
surface  of  the  extravasated  fluid.  I  endeavoured  to  ascertain  what 
proportion  of  water  a  given  quantity  of  the  alburnum  of  such  oak  trees 
contained  at  this  period,  and  I  found  that  1000  parts  lost  by  drying  only 
371  parts ;  which  is  not  more  than  the  weight  of  the  water  that  the 
cellular  substance  appears  capable  of  containing,  entirely  independent  of 
the  tubes.  That  the  tubes,  nevertheless,  are  not  always  empty,  but  that 
they  act  at  other  periods  of  the  year  as  reservoirs  for  the  sap,  I  have  given 
an  opinion  in  a  former  communication ;  and  I  am  now  in  possession  of 
facts  which  prove  them  to  perform  this  office,  even  in  the  heart  wood, 
to  a  much  greater  extent  than  1  had  ever  at  any  former  period  suspected ; 
and  which  incline  me  to  believe  that  the  durability  of  the  heart  wood,  as 
well  as  of  the  alburnum  of  the  oak,  will  be  found  to  depend  to  a  great 
extent  upon  the  period  in  which  the  tree  is  felled. 


PART  II. 
PAPERS    ON    PHYSIOLOGICAL   HORTICULTURE, 


READ  BEFORE 


THE  HORTICULTURAL  SOCIETY,  IN  THE  YEARS  1806  TO  1838. 

REPRINTED  FROM  THE  HORTICULTURAL  TRANSACTIONS. 


XVI OBSERVATIONS   ON   THE   MEANS   OF   PRODUCING    NEW  AND 

EARLY  FRUITS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  November  4.ih,  1806.] 

NATURE  has  given  to  man  the  means  of  acquiring  those  things  which 
constitute  the  comforts  and  luxuries  of  civilised  life,  though  not  the  things 
themselves ;  it  has  placed  the  raw  material  within  his  reach ;  but  has 
left  the  preparation  and  improvement  of  it  to  his  own  skill  and  industry. 
Every  plant  and  animal,  adapted  to  his  service,  is  made  susceptible  of 
endless  changes,  and,  as  far  as  relates  to  his  use,  of  almost  endless 
improvement.  Variation  is  the  constant  attendant  on  cultivation,  both 
in  the  animal  and  vegetable  world ;  and  in  each  the  offspring  are 
constantly  seen,  in  a  greater  or  less  degree,  to  inherit  the  character  of 
the  parents  from  which  they  spring. 

No  experienced  gardener  can  be  ignorant  that  every  species  of  fruit 
acquires  its  greatest  state  of  perfection  in  some  peculiar  soils  and 
situations,  and  under  some  peculiar  mode  of  culture  :  the  selection  of  a 
proper  soil  and  situation  must  therefore  be  the  first  object  of  the 
improver's  pursuit ;  and  nothing  should  be  neglected  which  can  add  to 
the  size,  or  improve  the  flavour  of  the  fruit  from  which  it  is  intended  to 
propagate.  Due  attention  to  these  points  will  in  almost  all  cases  be 
found  to  comprehend  all  that  is  necessary  to  insure  the  introduction  of 
new  varieties  of  fruit,  of  equal  merit  with  those  from  which  they  spring ; 
but  the  improver,  who  has  to  adapt  his  productions  to  the  cold  and 
unsteady  climate  of  Britain,  has  still  many  difficulties  to  contend  with ; 
he  has  to  combine  hardiness,  energy  of  character,  and  early  maturity, 
with  the  improvements  of  high  cultivation.  Nature  has  however  in  some 
measure  pointed  out  the  path  he  is  to  pursue ;  and,  if  it  be  followed 
with  patience  and  industry,  no  obstacles  will  be  found,  which  may  not  be 
either  removed,  or  passed  over. 


ON  PRODUCING    NEW    AND    EARLY    FRUITS,  173 

If  two  plants  of  the  vine  or  other  tree  of  similar  habits,  or  even  if 
obtained  from  cuttings  of  the  same  tree,  were  placed  to  vegetate,  during 
several  successive  seasons,  in  very  different  climates  :  if  the  one  were 
planted  on  the  banks  of  the  Rhine,  and  the  other  on  those  of  the  Nile, 
each  would  adapt  its  habits  to  the  climate  in  which  it  were  placed ;  and 
if  both  were  subsequently  brought,  in  early  spring,  into  a  climate  similar 
to  that  of  Italy,  the  plant  which  had  adapted  its  habits  to  a  cold  climate 
would  instantly  vegetate,  whilst  the  other  would  remain  perfectly  torpid. 
Precisely  the  same  thing  occurs  in  the  hot-houses  of  this  country,  where 
a  plant  accustomed  to  the  temperature  of  the  open  air  will  vegetate 
strongly  in  December,  whilst  another  plant  of  the  same  species,   and 
sprung  from  a  cutting  of  the  same  original  stock,  but  habituated  to  the 
temperature  of  a  stove,  remains  apparently  lifeless.     It  appears,  there- 
fore,  that  the  powers   of  vegetable  life,  in  plants  habituated  to  cold 
climates,  are   more  easily   brought   into  action   than    in  those  of  hot 
climates ;  or,  in  other  words,  that  the  plants  of  cold  climates,  are  most 
exciteable:   and  as  every  quality  in  plants  becomes  hereditary,  when 
the  causes  which    first  gave  existence  to  those  qualities    continue   to 
operate;  it  follows  that  their  seedling  offspring  have  a  constant  ten- 
dency to  adapt  their  habits  to  any  climate  in  which  art  or  accident 
places  them. 

But  the  influence  of  climate  on  the  habits  of  plants,  will  depend  less 
on  the  aggregate  quantity  of  heat  in  each  climate,  than  on  the  distribution 
of  it  in  the  different  seasons  of  the  year.      The  aggregate  temperature 
of  England,   and   of  those  parts    of    the    Russian   Empire   that    are 
under  the   same   parallels   of  latitude,  probably  does  not    differ   very 
considerably  ;  but,  in  the  latter,  the  summers  are  extremely  hot,  and 
the  winters  intensely  cold ;  and  the  changes  of  temperature  between  the 
different  seasons  are  sudden  and  violent.     In  the  spring  great  degrees  of 
heat  suddenly  operate  on  plants  which  have  been  long  exposed  to  intense 
cold,  and  in  which  excitability  has  accumulated  during  a  long  period  of 
almost  total  inaction  :  and  the  progress  of  vegetation  is  in  consequence 
extremely  rapid.    In  the  climate  of  England,  the  spring,  on  the  contrary, 
advances  with  slow  and  irregular  steps,   and  only  very  moderate  and 
slowly- increasing  degrees  of  heat  act  on  plants  in  which  the  powers  of 
life  have  scarcely  in  any  period  of  the  preceding  winter  been  totally 
inactive.     The   crab   is    a   native  of  both  countries,   and  has  adapted 
alike   its   habits  to    both ;    the    Siberian  variety  introduced    into    the 
climate  of  England,  retains  its  habits,  expands  its  leaves,  and  blossoms 
on  the  first  approach  of  spring,  and    vegetates  strongly  in  the   same 


174  OBSERVATIONS    ON    THE    MEANS    OF 

temperature  in  which  the  native  crab  scarcely  shows  signs  of  life ;  and 
its  fruit  acquires  a  degree  of  maturity,  even  in  the  early  part  of  an 
unfavourable  season,  which  our  native  crab  is  rarely,  or  never  seen  to 
attain. 

Similar  causes  are  productive  of  similar  effects  on  the  habits  of  culti- 
vated annual  plants  ;  but  these  appear  most  readily  to  acquire  habits  of 
maturity  in  warm  climates ;  for  it  is  in  the  power  of  the  cultivator  to 
commit  his  seeds  to  the  earth  at  any  season ;  and  the  progress  of  the 
plants  towards  maturity  will  be  most  rapid,  where  the  climate  and  soil 
are  most  warm.  Thus,  the  barley  grown  on  sandy  soils,  in  the  warmest 
parts  of  England,  is  always  found  by  the  Scotch  farmer,  when  introduced 
into  his  country,  to  ripen  on  his  cold  hills  earlier  than  his  crops  of  the 
same  kind  do,  when  he  uses  the  seeds  of  plants,  which  have  passed 
through  several  successive  generations  in  his  colder  climate;  and  in 
my  own  experience,  I  have  found  that  the  crops  of  wheat  on  some 
very  high  and  cold  ground,  which  I  cultivate,  ripen  much  earlier  when 
I  obtain  my  seed-corn  from  a  very  warm  district  and  gravelly  soil, 
which  lies  a  few  miles  distant,  than  when  I  employ  the  seeds  of  the 
vicinity. 

The  value,  to  the  gardener,  of  an  early  crop,  has  attracted  his  attention 
to  the  propagation  and  culture  of  the  earliest  varieties  of  many  species  of 
our  esculent  plants ;  but  in  the  improvement  of  these  he  is  more  often 
indebted  to  accident  than  to  any  plan  of  systematic  culture  ;  and  contents 
himself  with  merely  selecting  and  propagating  from  the  plant  of  the 
earliest  habits,  which  accident  throws  in  his  way ;  without  inquiring  from 
what  causes  those  habits  have  arisen :  and  few  efforts  have  been  made  to 
bring  into  existence  better  varieties  of  those  fruits  which  are  not  generally 
propagated  from  seeds,  and  which,  when  so  propagated,  of  necessity 
exercise,  during  many  years,  the  patience  of  the  cultivator,  before  he  can 
hope  to  see  the  fruits  of  his  labour. 

The  attempts  which  I  have  made  to  produce  early  varieties  of  fruit 
are,  I  believe,  all  that  have  yet  been  made ;  and  though  the  result  of 
them  is  by  no  means  sufficiently  decisive  to  prove  the  truth  of  the 
hypothesis  I  am  endeavouring  to  establish,  or  the  eligibility  of  the 
practice  I  have  adopted,  it  is  amply  sufficient  to  encourage  future 
experiment. 

The  first  species  of  fruit,  which  was  subjected  to  experiment  by  me, 
was  the  apple ;  some  young  trees  of  those  varieties  of  this  fruit,  from 
which  I  wished  to  propagate,  were  trained  to  a  south  wall,  till  they  pro- 
duced buds  which  contained  blossoms.  Their  branches  were  then,  in  the 


PRODUCING    NEW    AND    EARLY    FRUITS.  175 

succeeding  winter,  detached  from  the  wall,  and  removed  to  as  great  a 
distance  from  it,  as  the  pliability  of  their  stems  would  permit ;  and  in  this 
situation  they  remained  till  their  blossoms  were  so  far  advanced,  in  the 
succeeding  spring,  as  to  be  in  some  danger  of  injury  from  frost.  The 
branches  were  then  trained  to  the  wall,  where  every  blossom  I  suffered  to 
remain,  soon  expanded  and  produced  fruit.  This  attained  in  a  few 
months  the  most  perfect  state  of  maturity  ;  and  the  seeds  afforded  plants, 
which  have  ripened  their  fruit  very  considerably  earlier  than  other  trees, 
which  I  raised  at  the  same  time,  from  seeds  of  the  same  fruit,  which  had 
grown  in  the  orchard.  In  this  experiment  the  fecundation  of  the  blossoms, 
of  each  variety,  was  produced  by  the  farina  of  another  kind  ;  from  which 
process,  I  think,  I  obtained  in  this,  and  many  similar  experiments,  ari 
increased  vigour  and  luxuriance  of  growth ;  but  I  have  no  reasons  what- 
ever to  think  that  plants  thus  generated  ripen  their  fruit  earlier  than 
others,  which  are  obtained  by  the  common  methods  of  culture.  I  must 
therefore  attribute  the  early  maturity  of  those  I  have  described  to  the 
other  peculiar  circumstances  under  which  the  seeds  and  fruit  ripened, 
from  which  they  sprang. 

I  obtained,  by  the  same  mode  of  culture,  many  new  varieties,  which  are 
the  offspring  of  the  Siberian  crab  and  the  richest  of  our  apples,  with  the 
intention  of  affording  fruits  for  the  press,  which  might  ripen  well  in  cold 
and  exposed  situations.  The  plants,  thus  produced,  seem  perfectly  well 
calculated,  in  every  respect,  to  answer  the  object  of  the  experiment,  and 
possess  an  extraordinary  hardiness  and  luxuriance  of  growth.  The 
annual  shoots  of  some  of  them,  from  newly  grafted  trees  in  my  nursery, 
the  soil  of  which  is  by  no  means  rich,  exceeded  six  feet  and  a  half  in 
height,  in  the  last  season ;  and  their  blossoms  seem  capable  of  bearing 
extremely  unfavourable  weather  without  injury.  In  all  the  preceding 
experiments  some  of  the  new  varieties  inherited  the  character  of  the 
male,  and  others  of  the  female  parent  in  the  greatest  degree ;  and  of 
some  varieties  of  fruit  (particularly  the  golden  pippin)  I  obtained  a 
better  copy,  by  introducing  the  farina  into  the  blossom  of  another  apple, 
than  by  sowing  their  own  seeds ;  I  sent  a  new  variety  (the  Downton 
pippin)  which  was  thus  obtained  from  the  farina  of  the  golden  pippin,  to 
the  Horticultural  Society,  last  year  ;  but  those  specimens  afforded  but  a 
very  unfavourable  sample  of  it ;  for  the  season,  and  the  situation  in  which 
the  fruit  ripened,  were  very  cold,  and  almost  every  leaf  of  the  trees  had 
been  eaten  off  by  insects.  In  a  favourable  season  and  situation  it  will,  I 
believe,  be  found  little,  if  at  all,  inferior,  to  the  golden  pippin,  when  first 


176  OBSERVATIONS    ON    THE    MEANS    OF 

taken  from  the  tree  ;  but  it  is  a  good  deal  earlier,  and  probably  cannot 
be  preserved  so  long. 

I  proceed  to  experiments  on  the  grape ;  which  though  less  successful 
than  those  on  the  apple,  in  the  production  of  good  varieties,  are  not  less 
favourable  to  the  preceding  conclusions.  A  vinery  in  which  no  fires  are 
made  during  the  winter,  affords  to  the  vine  a  climate  similar  to  that 
which  the  southern  parts  of  Siberia  afford  to  the  apple  or  crab-tree :  in 
it  a  similarly  extensive  variation  of  temperature  takes  place,  and  the 
sudden  transition  from  great  comparative  cold  to  excessive  heat,  is  pro- 
ductive of  the  same  rapid  progress  in  the  growth  of  the  plants,  and 
advancement  of  the  fruit  to  maturity.  My  first  attempt  was  to  combine 
the  hardiness  of  the  blossom  of  the  black  cluster,  or  Burgundy  grape, 
with  the  large  berry  and  early  maturity  of  the  true  sweet  water*.  The 
seedling  plants  produced  fruit  in  my  vinery  at  three  or  four  years  old,  and 
the  fruit  of  some  of  them  was  very  early ;  but  the  bunches  were  short, 
and  ill-formed,  and  the  berries  much  smaller  than  those  of  the  sweet- 
water,  and  the  blossoms  did  not  set  by  any  means  so  well  as  I  had 
hoped. 

Substituting  the  white  chasselas  for  the  sweetwater,  I  obtained  several 
varieties,  whose  blossoms  appear  perfectly  hardy,  and  capable  of  setting 
well  in  the  open  air ;  and  the  fruit  of  some  of  them  is  ripening  a  good 
deal  earlier  in  the  present  year  than  that  of  either  of  the  parent  plants. 
The  berries,  however,  are  smaller  than  those  of  the  chasselas,  and  with 
less  tender  and  delicate  skins ;  and,  though  not  without  considerable 
merits  for  the  dessert,  they  are  generally  best  calculated  for  the  press  : 
for  the  latter  purpose,  in  a  cold  climate,  I  am  confident  that  one  or  two 
of  them  possess  very  great  excellence.  I  sent  a  bunch  of  one  of  those 
varieties  to  the  Horticultural  Society,  in  the  last  autumn,  and  I  propose 
to  send  two  or  three  others  in  the  present  year. 

I  have  subsequently  obtained  plants  from  the  white  chasselas  and 
sweetwater,  whose  appearance  is  much  more  promising ;  and  the  earliest 
variety  of  the  grape  I  have  ever  yet  seen,  sprang  from  a  seed  of  the 
sweetwater,  and  the  farina  of  the  red  front ignac.  This  is  also  a  very 
fine  grape,  resembling  the  frontignac  in  colour  and  form  of  the  bunch ; 
but  I  fear  its  blossoms  will  prove  too  tender  to  succeed  in  the  open  air  in 
this  country ;  a  single  bunch,  consisting  of  a  few  berries,  is  however,  all 
that  has  yet  existed  of  this  kind.  The  present  season  also  affords  me 

*  This  grape  is  often  confounded  by  gardeners,  both  with  the  white  chasselas  and  white 
muscadine. 


PRODUCING    NEW    AND    EARLY    FRUITS.  177 

two  new  varieties  of  the  vine,  with  striped  fruit,  and  variegated  autumnal 
leaves,  produced  by  the  white  chasselas  and  the  farina  of  the  Aleppo 
vine  :  one  of  these  has  ripened  extremely  early,  and  is,  I  think,  a  good 
grape.  When  perfectly  ripe,  I  propose  sending  a  bunch  of  it  for  the 
inspection  of  the  Horticultural  Society. 

In  all  attempts  to  obtain  new  varieties  of  fruit,  the  propagator  is  at  a 
loss  to  know  what  kinds  are  best  calculated  to  answer  his  purpose  ;  and 
therefore  I  have  mentioned  those  varieties  of  the  grape  from  which  1 
have  propagated  with  the  best  prospect  of  success.  My  experiments  are, 
however,  still  in  their  infancy ;  and  I  do  not  possess  the  means  of  making 
them  on  so  large  a  scale  or  in  so  perfect  a  manner  as  I  wish  ;  never- 
theless, the  facts  of  which  I  am  in  possession,  leave  no  grounds  of  doubt 
in  my  mind,  that  varieties  of  the  grape,  capable  of  ripening  perfectly  in 
our  climate,  when  trained  to  a  south  wall,  and  of  other  fruits  better 
calculated  for  our  climate  than  those  we  now  cultivate,  may  readily  be 
obtained ;  but  whether  the  mode  of  culture  I  have  adopted  and  recom- 
mended be  most  eligible  must  be  decided  by  future  and  more  extensive 
practice. 

I  have  made  experiments  similar  to  the  preceding  on  the  peach  ;  but 
I  can  say  no  more  of  the  result  of  them,  than  that  the  plants  possess  the 
most  perfect  degree  of  health  and  luxuriance  of  growth,  and  that  their 
leaves  afford  satisfactory  evidence  of  the  good  quality  of  the  future  fruit. 
I  am  ignorant  of  the  age  at  which  plants  of  this  species  become  capable 
of  producing  blossoms ;  but  the  rapid  changes  in  the  character  of  the 
leaves  and  growth  of  my  plants,  which  are  now  in  their  third  year, 
induce  me  to  believe  that  they  will  be  capable  of  producing  fruit  at 
three  or  four  years  old. 

I  shall  finish  my  paper  with  stating  a  few  conclusions,  which  I  have 
been  able  to  draw  in  the  course  of  many  years"  close  attention  to  the 
subject  on  which  I  write. 

New  varieties  of  every  species  of  fruit  will  generally  be  better  obtained 
by  introducing  the  farina  of  one  variety  of  fruit  into  the  blossom  of 
another,  than  by  propagating  from  any  single  kind.  When  an  experi- 
ment of  this  kind  is  made,  between  varieties  of  different  size  and 
character,  the  farina  of  the  smaller  kind  should  be  introduced  into 
the  blossoms  of  the  larger ;  for,  under  these  circumstances,  I  have 
generally  (but  with  some  exceptions)  observed  in  the  new  fruit  a  preva- 
lence of  the  character  of  the  female  parent ;  probably  owing  to  the 
following  causes.  The  seed-coats  are  generated  wholly  by  the  female 


178  ON    PRODUCING    NEW    AND    E/VRLY    FRUITS. 

parent,  and  these  regulate  the  bulk  of  the  lobes  and  plantule  :  and  I 
have  observed,  in  raising  new  varieties  of  the  peach,  that  when  one  stone 
contained  two  seeds,  the  plants  these  afforded  were  inferior  to  others. 
The  largest  seeds,  obtained  from  the  finest  fruit,  and  from  that  which 
ripens  most  perfectly  and  most  early,  should  always  be  selected.  It 
is  scarcely  necessary  to  inform  the  experienced  gardener,  that  it  will 
be  necessary  to  extract  the  stamina  of  the  blossoms  from  which  he 
proposes  to  propagate,  some  days  before  the  farina  begins  to  shed, 
when  he  proposes  to  generate  new  varieties  in  the  manner  I  have 
recommended. 

When  young  trees  have  sprung  from  the  seed,  a  certain  period  must 
elapse  before  they  become  capable  of  bearing  fruit,  and  this  period,  I 
believe,  cannot  be  shortened  by  any  means.  Pruning  and  transplanting 
are  both  injurious ;  and  no  change  in  the  character  or  merits  of  the 
future  fruit  can  be  effected,  during  this  period,  either  by  manure  or 
culture.  The  young  plants  should  be  suffered  to  extend  their  branches 
in  every  direction,  in  which  they  do  not  injuriously  interfere  with  each 
other ;  and  the  soil  should  just  be  sufficiently  rich  to  promote  a  moderate 
degree  of  growth,  without  stimulating  the  plant  to  preternatural  exertion, 
which  always  induces  disease*.  The  periods  which  different  kinds  of  fruit- 
trees  require  to  attain  the  age  of  puberty,  are  very  varied.  The  pear 
requires  from  twelve  to  eighteen  years ;  the  apple,  from  five  to  twelve,  or 
thirteen ;  the  plum  and  cherry,  four  or  five  years ;  the  vine  three  or 
four ;  and  the  raspberry,  two  years.  The  strawberry,  if  its  seeds  be 
sown  early,  affords  an  abundant  crop  in  the  succeeding  year.  My 
garden  at  present  contains  several  new  and  excellent  varieties  of 
this  fruitf,  some  of  which  I  shall  be  happy  to  send  to  the  Horticultural 
Society. 

*  The  soil  of  an  old  garden  is  peculiarly  destructive. 

t  The  hautboy  strawberry  does  not  appear  to  propagate  readily  with  the  other  varieties,  and 
may  possibly  belong  to  an  originally  distinct  species.  I  have,  however,  obtained  several 
offspring  from  its  farina  ;  but  they  have  all  produced  a  feeble  and  abortive  blossom.  If  nature, 
in  any  instance,  permits  the  existence  of  vegetable  mules  (but  this  I  am  not  inclined  to  believe), 
these  plants  seem  to  be  beings  of  that  kind. 


179 


XVII.— A  DESCRIPTION  OF  A  FORCING-HOUSE  FOR  GRAPES;  WITH 
OBSERVATIONS  ON  THE  BEST  METHOD  OF  CONSTRUCTING  HOUSES 
FOR  OTHER  FRUITS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  3rd,  1808.] 

So  much  difference  of  opinion  prevails  amongst  gardeners  respecting 
the  proper  forms  of  forcing-houses  that  two  are  rarely  constructed  quite 
alike,  though  intended  for  the  same  purposes ;  and  every  gardener  is 
prepared  to  contend  that  the  form  he  prefers  is  the  best,  and  to  appeal 
to  the  test  of  succcessful  experiment  in  support  of  his  opinion.  And  this 
he  is  generally  enabled  in  some  degree  to  do,  because  plants,  when 
properly  supplied  with  food  and  water  and  heat,  will  succeed  in  houses 
the  forms  of  which  are  very  defective ;  and  proper  attention  is  not  often 
paid  by  the  gardener  when  his  prejudices  satisfy  him  that  his  labours 
cannot  be  successful.  It  is,  however,  sufficiently  evident,  that  when  the 
same  fruit  is  to  be  ripened  in  the  same  climate  and  season  of  the  year, 
one  peculiar  form  must  be  superior  to  every  other ;  and  that  in  our 
climate,  where  sunshine  and  natural  heat  do  not  abound,  that  form, 
which  admits  the  greatest  quantity  of  light  through  the  least  breadth  of 
glass,  and  which  affords  the  greatest  regular  heat  with  the  least  expendi- 
ture of  fuel,  must  generally  be  the  best ;  and,  if  the  truth  of  this  position 
be  admitted,  it  will  be  very  easy  to  prove  that  few  of  our  forcing-houses 
are  at  present  even  moderately  well  constructed.  I  therefore  think  that 
if  plans  and  descriptions  of  such  forcing-houses  as  theory  and  practice 
prove  to  have  been  properly  constructed  for  the  culture  of  every  different 
species  of  fruit  were  published  by  the  Horticultural  Society,  much  useful 
information  might  be  conveyed  to  the  practical  gardener.  Under  these 
impressions  I  send  the  following  description  of  a  vinery  in  which  the  most 
abundant  crops  of  grapes  have  been  perfectly  ripened  within  less  time, 
and  with  less  expenditure  of  fuel,  than  I  have  witnessed  in  any  other 
instance. 

It  is  well  known  that  the  sun  operates  most  powerfully  in  the  forcing- 
house  when  its  rays  fall  most  perpendicularly  on  the  roof ;  because  the 
quantity  of  light  that  glances  off  without  entering  the  house  is  propor- 
tionate to  the  degree  of  obliquity  with  which  it  strikes  upon  the  surface 
of  the  glass ;  and  it  is,  therefore,  important  to  every  builder  of  a  forcing- 
house  to  know  by  what  elevation  of  the  roof  the  greatest  quantity  of  light 
can  be  made  to  pass  through  it.  To  ascertain  this  point  I  have  made 
many  experiments,  and  the  result  of  them  has  satisfied  me  that,  in 
latitude  52°,  the  best  elevation  is  about  that  of  34  degrees ;  and  relative 


180 


FORCING-HOUSES. 


to  that  elevation  the  position  of  the  sun,  in  different  parts  of  the  year, 
will  be  nearly  as  represented  in  the  annexed  sketch,  which  is  taken  from 
the  vinery  I  have  mentioned.  About  the  middle  of  May,  the  elevation 
of  the  sun  will  nearly  correspond  with  that  of  the  asterisk  A,  and  in  the 
beginning  of  June,  and  again  early  in  July,  it  will  be  vertical  at  B ;  and 
at  Midsummer  it  will,  at  C,  be  only  six  degrees  from  being  vertical.  The 
asterisk  D  points  out  its  position  at  the  equinoxes,  and  E  its  position  in 
Midwinter. 


In  this  building,  which  is  forty  feet  long,  and  is  heated  by  a  single 
fire-place,  the  flue  goes  entirely  round  without  touching  the  walls ;  and 
in  the  front  a  space  of  two  feet  is  left  between  the  flue  and  the  wall,  in 
the  middle  of  which  space  the  vines,  which  are  trained  to  the  roofs  about 
eleven  inches  from  the  glass,  are  planted ;  and,  as  both  the  wall  and  flue 
are  placed  on  arches,  the  vines  are  enabled  to  extend  their  roots  in  every 
direction,  whilst,  in  the  spring,  their  growth  is  greatly  excited  by  the 
heat  which  their  roots  and  stems  receive  from  the  flue.  Air  is  generally 
admitted  at  the  ends  only,  where  all  the  sashes  are  made  to  slide  to 
afford  a  free  passage  of  air  through  the  house,  when  necessary  to  prevent 
the  grapes  becoming  mouldy  in  damp  seasons.  About  four  feet  of  the 
upper  end  of  every  third  light  of  the  roof  is  made  to  lift  up,  (being 
attached  by  hinges  to  the  wood-work  on  the  top  of  the  back  wall,)  to 


FORCING-HOUSES.  181 

give  air  in  the  event  of  very  hot  and  calm  weather  ;  for  I  prefer  giving 
air  by  lifting  up  the  lights  to  letting  them  slide  down,  because,  when  the 
former  method  is  adopted,  no  additional  shade  is  thrown  on  the  plants. 

The  preceding  plan  is  here  particularly  recommended  for  a  vinery 
only ;  but  I  am  confident  that,  by  sinking  the  front  wall  below  the  level 
of  the  ground  and  making  a  small  change  in  the  form  of  the  bark-bed, 
the  same  elevation  of  roof  may  be  made  equally  applicable  to  the  pine- stove, 
and  that  no  upright  front  glass  ought,  in  any  case  whatever,  to  be  used ; 
for  light  can  always  be  more  beneficially  admitted  by  adding  to  the  length 
of  the  roof,  if  that  be  properly  elevated ;  and  much  expence  may  be 
saved  both  in  the  building  and  in  fuel.  For  forcing  the  peach  or  nectarine 
I  must,  however,  observe  that  I  think  any  house  of  the  preceding  dimen- 
sions wholly  improper ;  and  I  propose  to  submit  a  plan  for  the  improved 
culture  of  those  fruits  to  the  Horticultural  Society  at  a  future  opportunity. 

The  vine  often  bleeds  excessively  when  pruned  in  an  improper  season, 
or  when  accidentally  wounded,  and  I  believe  no  mode  of  stopping  the 
flow  of  the  sap  is  at  present  known  to  gardeners.  I  therefore  mention 
the  following,  which  I  discovered  many  years  ago,  and  have  always 
practised  with  success  : — if  to  four  parts  of  scraped  cheese  be  added 
one  part  of  calcined  oyster  shells,  or  other  pure  calcareous  earth,  and 
this  composition  be  pressed  strongly  into  the  pores  of  the  wood,  the 
sap  will  instantly  cease  to  flow;  so  that  the  largest  branch  may  of  course 
be  taken  off  at  any  season  with  safety. 


XVIII.— ON    THE     MANAGEMENT     OF    THE     ONION. 
[Read  before  the  HORTICULTURAL  SOCIETY,  April  4th,  1809.]  . 

THE  first  object  of  the  Horticultural  Society  being  to  point  out 
improvements  in  the  culture  of  those  plants  which  are  extensively  useful 
to  the  public,  I  send  a  few  remarks  on  the  management  of  one  of  these,  the 
onion  :  which  both  constitutes  one  of  the  humble  luxuries  of  the  poor,  and 
finds  its  way,  in  various  forms,  to  the  tables  of  the  affluent  and  luxurious. 

Every  bulbous-rooted  plant,  and  indeed  every  plant  which  produces 
leaves,  and  lives  longer  than  one  year,  generates,  in  one  season,  the  sap, 
or  vegetable  blood,  which  composes  the  leaves  and  roots  of  the  succeed- 
ing spring ;  and  when  the  sap  has  accumulated  during  one  or  more 
seasons,  it  is  ultimately  expended  in  the  production  of  blossoms  and 
seeds.  This  reserved  sap  is  deposited  in,  and  composes  in  a  great 


182  ON    THE    ONION. 

measure,  the  bulb;  and  the  quantity  accumulated,  as  well  as  the  period 
required  for  its  accumulation,  varies  greatly  in  the  same  species  of  plant, 
under  more  or  less  favourable  circumstances.  Thus  the  onion,  in  the 
south  of  Europe,  acquires  a  much  larger  size  during  the  long  and  warm 
summers  of  Spain  and  Portugal,  in  a  single  season,  than  the  colder 
climate  of  England ;  but  under  the  following  mode  of  culture,  which  I 
have  long  practised,  two  summers  in  England  produce  nearly  the  effect 
of  one  in  Spain  or  Portugal,  and  the  onion  assumes  nearly  the  form 
and  size  of  those  thence  imported. 

Seeds  of  the  Spanish  or  Portugal  onion  are  sown  at  the  usual  period 
in  the  spring,  very  thickly,  and  in  poor  soil ;  generally  under  the  shade 
of  a  fruit-tree ;  and  in  such  situations  the  bulbs,  in  the  autumn,  are  rarely 
found  much  to  exceed  the  size  of  a  large  pea.  These  are  then  taken 
from  the  ground,  and  preserved  till  the  succeeding  spring,  when  they  are 
planted  at  equal  distances  from  each  other,  and  they  afford  plants  which 
differ  from  those  raised  immediately  from  seed,  only  in  possessing  much 
greater  strength  and  vigour,  owing  to  the  quantity  of  previously  generated 
sap  being  much  greater  in  the  bulb  than  in  the  seed.  The  bulbs,  thus 
raised,  often  exceed  considerably  five  inches  in  diameter,  and  being  more 
mature,  they  are  with  more  certainty  preserved,  in  a  state  of  perfect 
soundness,  through  the  winter  than  those  raised  from  seed  in  a  single 
season.  The  same  effects  are.  in  some  measure,  produced  by  sowing  the 
seeds  in  August,  as  is  often  done ;  but  the  crops  often  perish  during  the 
winter,  and  the  ground  becomes  compressed  and  saddened  (to  use  an 
antiquated  term)  by  the  winter  rains  ;  and  I  have  in  consequence  always 
found  that  any  given  weight  of  this  plant  may  be  obtained,  with  less 
expence  to  the  grower,  by  the  mode  of  culture  I  recommend,  than  by 
any  other  which  I  have  seen  practised. 


XIX.— ON  POTATOES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  6,  1810.] 

IN  a  paper  lately  read  before  the  Society,  I  described  a  method  of 
cultivating  early  varieties  of  the  potato,  by  which  any  of  those,  which 
do  not  usually  blossom,  may  be  made  to  produce  seeds,  and  thus  afford 
the  means  of  obtaining  many  early  varieties.  I  also  offered  a  conjecture, 
that  varieties  of  moderately  early  habits,  and  luxuriant  growth,  might 
be  formed,  which  would  be  found  well  adapted  to  field-culture,  and  be 


ON    POTATOES.  183 

ready  to  be  taken  from  the  soil  in  the  end  of  August,  or  the  beginning  of 
September ;  so  that  the  farmer  might  be  allowed  ample  time  to  prepare 
the  same  ground  for  a  crop  of  wheat.  I  am  now  enabled  to  state,  that 
the  success  of  the  experiment  has  in  both  cases  fully  answered  every 
expectation  that  I  had  formed. 

The  facts  that  I  have  stated  in  the  paper  above  referred  to,  and  more 
fully  in  the  Philosophical  Transactions,  are,  I  believe,  sufficient  to  prove, 
that  the  same  fluid,  or  sap,  gives  existence  alike  to  the  tuber,  and  the 
blossom  and  seeds,  and  that  whenever  a  plant  of  the  potato  affords 
either  seeds  or  blossoms,  a  diminution  of  the  crop  of  tubers,  or  an 
increased  expenditure  of  the  riches  of  the  soil,  must  necessarily  take 
place.  It  has  also  been  proved  by  others,  as  well  as  myself,  that  the 
crop  of  tubers  is  increased  by  destroying  the  fruit-stalks  and  immature 
blossoms  as  soon  as  they  appear,  and  I  therefore  conceived  that  consider- 
able advantages  would  arise,  if  varieties  of  sufficiently  luxuriant  growth 
and  large  produce,  for  general  culture,  could  be  formed,  which  would 
never  produce  blossoms. 

I  have  since  had  the  gratification  to  find  that  such  are  readily  obtained, 
by  the  means  which  I  have  detailed,  and  I  am  disposed  to  annex  more 
importance  to  the  improvement  of  our  most  useful  plants,  than  any 
writer  on  agriculture  has  hitherto  done;  because  whatever  increased 
value  is  thus  added  to  the  produce  of  the  soil,  is  obtained  without  any 
increased  expence  or  labour,  and  therefore  is  just  so  much  added  to 
individual  and  national  wealth. 

j&  I  formerly  supposed  that  all  varieties  of  the  potato,  which  ripened 
early  in  the  autumn,  would  necessarily  vegetate  early  in  the  ensuing 
spring,  and  could  therefore  be  fit  for  use  only  during  winter;  but  I  have 
found  that  the  habit  of  acquiring  maturity  early  in  the  autumn,  is  by  no 
means  necessarily  connected  with  the  habit  of  vegetating  early  in  the 
spring ;  and  therefore  by  a  proper  selection  of  varieties,  the  season  of 
planting  crops,  for  all  purposes,  may  be  extended  from  the  beginning  of 
March,  nearly  to  the  middle  of  May,  and  each  variety  be  committed  to 
the  soil  exactly  at  the  most  advantageous  period. 

A  variety,  however,  uhich  does  not  vegetate  till  late  in  the  spring,  and 
which  ripens  early  in  the  autumn,  cannot  1  conclude,  particularly  in  dry 
soils  and  seasons,  afford  so  large  a  produce  as  one  which  vegetates  more 
early  :  I,  nevertheless,  obtained  so  large  a  crop  from  one  which  vegetates 
remarkably  late  in  the  spring,  and  ripens  rather  early  in  the  autumn,  that 
I  was  induced  to  ascertain,  by  weighing,  to  what  the  produce  would  have 
amounted  had  the  crop  extended  over  an  acre,  and  I  found  that  it  would 
have  been  21  tons,  11  cwt.  80  Ib.  or  48,352  Ibs. 


184  ON    POTATOES. 

In  this  calculation  the  external  rows,  which  derived  superior  advantage 
from  air  and  light,  were  excluded.  No  more  manure,  or  culture,  than 
is  usually  given,  had  been  employed,  for  the  crop  was  not  planted  with 
any  intention  of  having  it  weighed :  the  wet  summer  was,  however,  very 
favourable. 

I  am  not  acquainted  with  the  ordinary  amount  of  the  weight  of  a  good 
crop  of  potatoes,  upon  an  acre  of  ground  in  a  favourable  soil,  when  well- 
manured  and  cultivated ;  but  I  am  confident,  that  it  may  generally  be 
made  to  exceed  twenty  tons,  by  a  proper  selection  of  varieties :  and  if 
four  pounds  of  good  potatoes  afford,  as  is  generally  supposed,  at  least  as 
much  nutriment  as  one  pound  of  wheat,  the  produce  of  an  acre  of 
potatoes,  such  as  I  have  described,  is  capable  of  supporting  as  large  a 
population,  as  eight  acres  of  wheat,  admitting  the  calculation  of  Mr. 
Arthur  Young,  that  the  average  produce  of  an  acre  of  wheat  is  22^ 
bushels  or  1440  Ibs. ;  and  as  an  acre  of  wheat  will  certainly  support  as 
large  a  number  of  people  as  five  acres  of  permanent  pasture,  it  follows, 
that  an  acre  of  potatoes  affords  as  much  food  for  mankind,  as  forty  acres 
of  permanent  pasture :  an  important  subject  for  consideration,  in  a 
country  where  provisions  are  scarce  and  dear,  and  where  so  high  bounties 
on  pasture  are  paid  in  the  form  of  taxes  on  tillage,  that  the  extent  of 
permanent  pasture  is  certainly  and  consequently  increasing  :  and  it  must 
increase,  under  existing  circumstances;  for  it  pays  a  higher  rent  to 
the  landlord,  and  relieves  the  farmer  from  much  labour,  anxiety,  and 
vexation. 

To  what  extent  a  crop  of  potatoes  will  generally  be  increased  by  the 
total  prevention  of  all  disposition  to  blossom,  the  soil  and  variety  being, 
in  all  other  respects,  the  same,  it  is  difficult  to  conjecture ;  but  I  imagine 
that  the  expenditure  of  sap  in  the  production  of  fruit-stalks  and  blossoms 
alone  would  be  sufficient  to  occasion  an  addition,  of  at  least  an  ounce,  to 
the  weight  of  the  tubers  of  each  plant,  and  if  each  square  yard  were  to 
contain  eight  plants,  as  in  the  crop  I  have  mentioned,  the  increased 
produce  of  an  acre  would  considerably  exceed  a  ton,  and  of  course 
be  sufficient,  in  almost  all  cases,  to  pay  the  rent  of  the  ground. 

I  do  not  know  how  far  other  parts  of  England  are  well  supplied  with 
good  varieties  of  potatoes  ;  but  those  cultivated  in  my  neighbourhood  in 
Herefordshire  and  Shropshire,  are  generally  very  bad.  Many  of  them 
have  been  introduced  from  Ireland,  and  to  that  climate  they  are 
probably  well  adapted ;  for  the  Irish  planter  is  secure  from  frost  from 
the  end  of  A  pril  nearly  to  the  end  of  November  :  but  in  England,  the 
potato  is  never  safe  from  frost  till  near  the  end  of  May  ;  indeed  I  have 


ON    POTATOES.  185 

seen  the  leaves  and  stems  of  a  crop,  in  a  very  low  situation,  completely 
destroyed  as  late  as  the  13th  of  June,  and  they  are  generally  injured 
before  the  middle,  and  sometimes  in  the  first  week  of  September. 

The  Irish  varieties,  being  excessively  late,  are  almost  always  killed  by 
the  frost  whilst  in  full  blossom  ;  when  omitting  all  consideration  of  the 
useless  expenditure  of  manure,  it  may  justly  be  questioned  whether  the 
tubers  of  such  plants,  being  immature,  can  afford  as  nutritive,  or  as 
wholesome  food,  as  others  which  have  acquired  a  state  of  perfect 
maturity. 

The  preceding  statement  will,  I  trust,  point  out  to  the  Horticultural 
Society  the  importance  of  obtaining  improved  varieties  of  the  potato, 
and  I  believe  no  plant  existing  to  be  more  extensively  capable  of  improve- 
ment, relatively  to  the  climate  of  England  ;  and  if  practical  evidence 
were  wanted  to  prove  the  extent,  to  which  the  culture  of  the  potato  is 
calculated  to  increase  and  support  the  population  of  a  country,  Ireland 
most  amply  affords  it ;  where  population  has  increased  amongst  the 
Catholic  poor,  with  almost  unprecedented  rapidity,  within  the  last 
twenty  years,  under  the  pressure  of  more  distress  and  misery,  than  has 
perhaps  been  felt  in  any  other  spot  in  Europe. 

1  shall  conclude  my  present  communication  with  some  remarks  upon 
the  origin  and  cure  of  a  disease,  the  Curl,  which  a  few  years  ago  destroyed 
many  of  our  best  varieties  of  the  potato  ;  and  to  the  attacks  of  which 
every  good  variety  will  probably  be  subject. 

I  observed  that  several  kinds  of  potatoes,  dry  and  farinaceous  in  their 
nature,  which  I  cultivated,  produced  curled  leaves,  whilst  those  of  other 
kinds,  which  were  soft  and  aqueous,  were  perfectly  well  formed  ;  whence 
I  was  led  to  suspect,  that  the  disease  originated  in  the  preternaturally 
inspissated  state  of  the  sap  in  the  dry  and  farinaceous  varieties.  I  con- 
ceived that  the  sap,  if  not  sufficiently  fluid,  might  stagnate  in,  and  close, 
the  fine  vessels  of  the  leaf  during  its  growth  and  extension,  and  thus 
occasion  the  irregular  contractions  which  constitute  this  disease ;  and  this 
conclusion,  which  I  drew  many  years  ago,  is  perfectly  consistent  with  the 
opinions  I  have  subsequently  entertained,  respecting  the  formation  of 
leaves.  I  therefore  suffered  a  quantity  of  potatoes,  the  produce  almost 
wholly  of  diseased  plants,  to  remain  in  the  heap,  where  they  had  been 
preserved  during  winter,  till  each  tuber  had  emitted  shoots  of  three  or 
four  inches  long.  These  were  then  carefully  detached,  with  their  fibrous 
roots,  from  the  tubers,  and  were  committed  to  the  soil ;  where  having 
little  to  subsist  upon,  except  water,  I  concluded  the  cause  of  the  disease, 
if  it  were  the  too  great  thickness  of  the  sap,  would  be  effectually  removed ; 


18G  ON    POTATOES. 

and  I  had  the  satisfaction  to  observe,  that  not  a  single  curled  leaf  was 
produced  ;  though  more  than  nine-tenths  of  the  plants,  which  the  same 
identical  tubers  subsequently  produced,  were  much  diseased. 

In  the  spring  of  1 808,  Sir  John  Sinclair  informed  me  that  a  gardener 
in  Scotland,  Mr.  Crozer,  had  discovered  a  method  of  preventing  the  curl, 
by  taking  up  the  tubers  before  they  are  nearly  full  grown,  and  conse- 
quently before  they  became  farinaceous.  Mr.  Crozer,  therefore,  and 
myself,  appear  to  have  arrived  at  the  same  point  by  very  different  routes ; 
for  by  taking  his  potatoes,  whilst  immature,  from  the  parent  stems,  he 
probably  retained  the  sap  nearly  in  the  state  to  which  my  mode  of 
culture  reduced  it.  I  therefore  conclude,  that  the  opinions  I  first 
formed,  are  well  founded ;  and  that  the  disease  may  be  always  removed 
by  the  means  I  employed,  and  its  return  prevented  by  those  adopted  by 
Mr.  Crozer. 


XX.— ON    THE     CONSTRUCTION     OF    PEACH-HO  USES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  April  3rd,  1810.] 

SCARCELY  any  fruit  can  be  raised  in  greater  abundance,  or  with  fewer 
chances  of  failure,  than  the  peach  in  a  forcing-house ;  where  the  insects, 
which  often  prove  so  formidable  in  the  open  air,  are  easily  destroyed,  and 
where  the  tree  is  subject  to  scarcely  any  other  disease  than  the  mildew ; 
and  I  have  reason  to  believe,  that  the  appearance  of  this  disease  may,  in 
general,  be  very  easily  prevented  by  selection  of  proper  soil,  and  by 
proper  management.  But  though  a  crop  of  peaches,  or  nectarines,  is 
very  easily  obtained  under  glass,  experience  seems  to  have  proved  that 
neither  of  these  fruits  acquire  perfection,  either  in  richness  or  flavour, 
unless  they  be  exposed  to  the  full  influence  of  the  sun,  during  their  last 
swelling,  without  the  intervention  of  the  glass.  It  has  consequently  been 
the  practice,  in  some  gardens,  to  take  off  the  lights  wholly  before  the 
fruit  begins  to  ripen ;  and  in  warm  seasons,  and  favourable  situations, 
this  mode  of  management  succeeds  perfectly  well.  But  in  the  colder 
parts  of  England  this  cannot  be  done ;  and  if  the  weather,  in  any  part, 
prove  cold  and  wet,  just  after  the  lights  are  taken  off,  the  growth  of  the 
fruit  is  suddenly  checked,  and  its  quality  greatly  injured  :  and  I  have 
never  met  with  the  peach  in  so  much  perfection,  as  when  it  has  been 
raised  in  a  house  where  it  could  be  conveniently  exposed  to  the  sun  in 


ON    THE    CONSTRUCTION    OF    PEACH-HOUSES. 


187 


warm  and  bright  days,  and  secluded  from  the  cold  night  air,  and  rain ; 
which  mode  of  management  can,  I  think,  be  adopted  most  conveniently 
in  a  house  constructed  according  to  the  annexed  sketch  and  dimensions, 
and  the  following  directions. 


As  the  lights,  to  be  moved  to  the  required  extent  with  facility,  must 
necessarily  be  short,  the  back  wall  of  the  house  must  scarcely  extend  nine 
feet  in  height;  and  this  height  raises  the  rafters  sufficiently  high  to 
permit  the  tallest  person  to  walk  with  perfect  convenience  under  them. 
The  lights  are  divided  in  the  middle,  at  the  point  A,  and  the  lower 
are  made  to  slide  down  to  the  point  D,  and  the  upper  to  the  point 
A*.  The  flue  enters  on  the  east  or  west  end,  as  most  convenient, 
and  passes  within  six  inches  of  the  east  and  west  wall ;  but  not  within 
less  than  two  feet  of  the  low  front  wall ;  and  it  returns  in  a  parallel 
line  through  the  middle  of  the  house,  in  the  direction  either  east 
or  west,  and  goes  out  at  the  point  at  which  it  entered.  The  house 
takes  two  rows  of  peach  or  nectarine  trees,  one  of  which  is  trained 
on  trellises,  with  intervals  between,  for  the  gardener  to  pass,  parallel 
with  the  dotted  line  C.  These  trees  must  be  planted  between  the  flue 
and  the  front  wall ;  and  the  other  row  near  the  back  wall,  against  which 
they  are  to  be  trained. 

If  early  varieties  be  planted  in  the  front,  and  the  earliest  where  the 
flue  first  enters,  these  being  trained  immediately  over  the  flue  and  at  a 
small  distance  above  it,  will  ripen  first ;  and  if  the  lower  lights  be  drawn 

*  A  bar  of  wood  must  extend  from  D  to  B,  opposite  the  middle  of  each  lower  light,  to  sup- 
port it  when  drawn  down. 


188  ON    THE    CONSTRUCTION    OF    PEACH-HOUSES. 

down  in  fine  weather,  to  the  point  B,  every  part  of  the  fruit  on  the  trees, 
which  are  trained  nearly  horizontally,  along  the  dotted  line  C,  will  receive 
the  full  influence  of  the  sun.  The  upper  lights  must  be  moved,  as  usual, 
by  cords  and  pulleys ;  and  if  these  be  let  down  to  the  point  A,  after  the 
fruit  on  the  front  trees  is  gathered,  every  part  of  the  trees  on  the  back 
wall  will  be  fully  exposed  to  the  sun,  at  any  period  of  the  spring  and 
summer,  after  the  middle  of  April,  without  the  intervention  of  the  glass. 
A  single  fire-place  will  be  sufficient  for  a  house  of  50  feet  long ;  and  I 
believe  the  foregoing  plan  and  dimensions  will  be  found  to  combine  more 
advantages  than  can  ever  be  obtained  in  a  higher  or  wider  house. 

Both  the  walls  and  flue  must  stand  on  arches,  to  permit  the  roots  of 
the  trees  to  extend  themselves  in  every  direction,  beyond  the  limits  of 
the  walls;  for  whatever  be  the  more  remote  causes  of  mildew,  the 
immediate  cause  generally  appears  to  be  want  of  moisture  beneath  the 
soil,  particularly  if  it  be  combined  with  excess  of  moisture,  or  dampness, 
above  it.  In  experiments  which  I  have  made  to  discover  the  cause  of 
mildew,  in  other  plants,  I  have  found  that  nothing  so  effectually  prevents 
its  appearance  as  abundant  moisture  beneath  the  soil ;  and  many  gar- 
deners, who  have  had  the  misfortune  to  cultivate  the  peach  in  situations 
where  the  roots,  at  a  small  depth  beneath  the  soil,  were  destroyed  by 
water  during  winter,  or  where  the  same  effect  was  produced  by  the 
unfavourable  nature  of  the  subsoil,  must  have  observed  the  injurious 
effects  of  mildew. 

I  shall  conclude  my  paper  with  observing,  that  I  have  never  seen  the 
peach  in  so  great  a  state  of  perfection,  as  when  cultivated  very  nearly 
according  to  the  preceding  directions :  and  I  estimate  so  highly  the 
advantages  of  bringing  forward  the  fruit  under  glass,  till  it  is  nearly  full- 
grown,  and  then  exposing  it  to  the  stronger  stimulus  of  sunshine,  without 
the  intervention  of  the  glass,  and  excluding  it  from  rain  and  dews,  that  I 
believe  the  peach  might  be  thus  ripened  in  greater  perfection  at  St. 
Petersburg,  in  a  house  properly  adapted  to  the  latitude  of  that  place, 
than  in  the  open  air  at  Rome  or  Naples. 


189 


XXI.— A  CONCISE  VIEW  OF  THE  THEORY  RESPECTING  VEGETATION, 
LATELY  ADVANCED  IN  THE  PHILOSOPHICAL  TRANSACTIONS,  ILLUS- 
TRATED IN  THE  CULTURE  OF  THE  MELON. 

[Read  before  the  HORTICULTURAL  SOCIETY,  January  2,  1811.] 

THE  council  of  the  Horticultural  Society  having  desired  that  I  would 
send  to  the  society  a  general  view  of  my  Theory  of  Vegetable  Physiology, 
which  has  been  published  by  the  Royal  Society,  I  have  great  pleasure  in 
obeying  their  wishes ;  and  conceiving  that  I  shall  be  able  to  render  it 
more  clear  and  useful,  by  making  it  illustrative  of  the  proper  culture  of 
some  particular  plant,  and  by  referring  the  reader  to  the  papers  in  the 
Philosophical  Transactions  for  evidence  in  support  of  the  circumstances 
stated, — I  have  for  this  purpose  chosen  the  melon. 

A  seed,  exclusive  of  its  seed-coats,  consists  of  one  or  more  cotyledons, 
a  plumule  or  bud,  and  the  caudex  or  stem  of  the  future  plant,  which  has 
generally,  though  erroneously,  been  called  its  radicle  *.  In  these  organs, 
but  principally  in  the  cotyledons,  is  deposited  as  much  of  the  concrete 
sap  of  the  parent  plant  as  is  sufficient  to  feed  its  offspring,  till  that  has 
attached  itself  to  the  soil,  and  become  capable  of  absorbing  and  assimi- 
lating new  matter. 

The  plumule  differs  from  the  bud  of  the  parent  plant  in  possessing  a 
new  and  independent  life,  and  thence  in  assuming,  in  its  subsequent 
growth,  different  habits  from  those  of  the  parent  plant.  The  organisable 
matter  which  is  given  by  the  parent  to  the  offspring  in  this  case,  probably 
exists  in  the  cotyledons  of  the  seed,  in  the  same  state  as  it  exists  in  the 
alburnum  of  trees  ;  and,  like  that,  it  apparently  undergoes  considerable 
changes  before  it  becomes  the  true  circulating  fluid  of  the  plant ;  in  some 
it  becomes  saccharine,  in  others  acrid  and  bitter,  during  germination  t. 
In  this  process  the  vital  fluid  is  drawn  from  the  cotyledons  into  the 
caudex  of  the  plumule  or  bud,  through  vessels  which  correspond  with 
those  of  the  bark  of  the  future  tree,  and  are  indeed  perfect  cortical 
vessels  J.  From  the  point  of  the  caudex  springs  the  first  root,  which,  at 
this  period,  consists  wholly  of  bark  and  medulla,  without  any  alburnous 
or  woody  matter  ;  and,  if  uninterrupted  by  any  opposing  body,  it 
descends  in  a  straight  line  towards  the  centre  of  the  earth,  in  whatever 
position  the  seed  has  been  placed,  provided  it  has  been  permitted  to 
vegetate  at  rest§. 

Soon  after  the  first  root  has  been  emitted,  the  caudex  elongates,  and 
taking  a  direction  diametrically  opposite  to  that  of  the  root,  it  raises,  in 

*  See  above,  No.  XII.          f  Above,  No.  V.          +  Above,  No.  XII.          §  Above,  No.  XII. 


190  THEORY     OF    VEGETATION 

a  great  many  kinds  of  plants,  the  cotyledons  out  of  the  soil,  which  then 
become  the  seminal  leaves  of  the  young  plant*.  During  this  period  the 
young  plant  derives  nutriment  almost  wholly  from  the  cotyledons  or  seed- 
leaves,  and  if  those  be  destroyed  it  perishes.  Gravitation,  by  operating 
on  bodies  differently  organised  and  of  different  modes  of  growth,  appears 
at  once  the  cause  why,  in  the  preceding  case,  the  root  descends,  and  why 
the  elongated  plumule  ascends  f. 

The  bark  of  the  root  now  begins  to  execute  its  office  of  depositing 
alburnous  or  woody  matter  ;  and  as  soon  as  this  is  formed,  the  sap, 
which  had  hitherto  descended  only  through  the  cortical  vessels,  begins  to 
ascend  through  the  alburnum.  The  plumule  in  consequence  elongates, 
its  leaves  enlarge  and  unfold,  and  a  set  of  vessels,  which  did  not  exist  in 
the  root,  are  now  brought  into  action.  These,  which  I  have  called  the 
central  vessels,  surround  the  medulla,  and,  between  it  and  the  bark,  form 
a  circle,  upon  which  the  alburnum  is  deposited  by  the  bark,  in  the  form 
of  wedges,  or  like  the  stones  of  an  arch  j.  Through  these  vessels,  which 
diverge  into  the  leaf-stalks,  the  sap  ascends,  and  is  dispersed  through  the 
vessels  and  parenchymatous  substance  of  the  leaf;  and,  in  this  organ, 
the  fluid  recently  absorbed  from  the  soil  becomes  converted  into  the  true 
sap  or  blood  of  the  plant ;  and  as  this  fluid,  during  germination,  descended 
from  the  cotyledons  and  seed-leaves  of  the  plant,  it  now  descends  from 
its  proper  leaves,  and  adds,  in  its  descent,  to  the  bulk  of  the  stem  and 
the  growth  of  the  roots.  Alburnum  is  also  deposited  in  the  stem  of  the 
plant,  below  the  proper  leaves,  as  it  was  previously  deposited  below 
the  seed-leaves ;  and  from  this  spring  other  central  vessels,  which  give 
existence  to,  and  feed,  other  leaves  and  buds  §. 

A  considerable  part  of  the  ascending  fluid  must  necessarily  have  been 
recently  absorbed  from  the  soil ;  but  in  the  alburnum  it  becomes  mixed 
with  the  true  sap  of  the  plant,  a  portion  of  which,  during  its  descent 
down  the  bark,  appears  to  secrete  into  the  alburnum  through  passages 
correspondent  to  the  anastomosing  vessels  of  the  animal  economy  ||.  For 
as  the  cotyledons  or  seed-leaves  first  afforded  the  organisable  matter 
which  composed  the  first  proper  leaves,  so  these,  when  full-grown,  prepare 
the  fluid  which  generates  other  young  leaves  ;  the  health  and  growth  of 
which  are  as  much  dependent  on  the  older  leaves  as  those,  when  first 
formed,  were  upon  the  cotyledons  ^|. 

The  power  of  each  proper  leaf  to  generate  sap,  in  any  given  species 
and  variety  of  plant,  appears  to  be  in  the  compound  ratio  of  its  width, 

*  See  above,  No.  VII.      t  Above,  No.  VII.      J  Above,  No.  II.       §  Above,  Nos.  II.  and  V. 
||  Above,  No.  IX.         fl  Above,  No.  V. 


ILLUSTRATED    IN    THE    CULTURE    OF    THE    MELON.  191 

its  thickness,  and  the  exposure  of  its  upper  surface  to  light  in  proper 
temperature.  As  the  growth  of  the  plant  proceeds,  the  number  and 
width  of  the  mature  leaves  increase  rapidly  in  proportion  to  the  number 
of  young  leaves  to  be  formed  ;  and  the  creation  consequently  exceeds  the 
expenditure  of  true  sap.  This  therefore  accumulates  during  a  succession 
of  weeks,  or  months,  or  years,  according  to  the  natural  habits  and 
duration  of  the  plant,  varying  considerably  according  to  the  soil  and 
climate  in  which  each  individual  grows  ;  and  the  sap  thus  generated  is 
deposited  in  the  bulb  of  the  tulip,  in  the  tuber  of  the  potato,  in  the 
fibrous  roots  of  grasses,  and  in  the  alburnum  of  trees,  during  winter, 
and  is  dispersed  through  their  foliage  and  bark  during  the  spring  and 
summer  *. 

As  soon  as  the  plant  has  attained  its  age  of  puberty,  a  portion  of  its 
sap  is  expended  in  the  production  of  blossoms  and  fruit.  These  originate 
from  and  are  fed  by  central  vessels,  apparently  similar  to  those  of  the 
succulent  annual  shoot  and  leaf-stalk,  and  which  probably  convey  a 
similar  fluid ;  for  a  bunch  of  grapes  grew  and  ripened  when  grafted  upon 
a  leaf-stalk ;  and  a  succulent  young  shoot  of  the  vine,  under  the  same 
circumstances,  acquired  a  growth  of  many  feetf. 

The  fruit,  or  seed-vessel,  appears  to  be  generated  wholly  by  the  pre- 
pared sap  of  the  plant,  and  its  chief  office  to  be  that  of  adapting  the 
fluids,  which  ascend  into  it,  to  afford  proper  nutriment  to  the  seed  it 
contains^. 

I  proceed  to  offer  some  observations  upon  the  proper  culture  of  the 
melon. 

There  is  not,  I  believe,  any  species  of  fruit  at  present  cultivated  in  the 
gardens  of  this  country,  which  so  rarely  acquires  the  greatest  degree  of 
perfection,  which  it  is  capable  of  acquiring  in  our  climate,  as  the  melon. 
It  is  generally  found  so  defective  both  in  richness  and  flavour,  that  it  ill 
repays  the  expence  and  trouble  of  its  culture ;  and  my  own  gardener, 
though  not  defective  in  skill  or  attention,  had  generally  so  little  success, 
that  I  had  given  him  orders  not  to  plant  melons  again.  Attending, 
however,  after  my  orders  were  given,  more  closely  to  his  mode  of  culture, 
and  to  that  of  other  gardeners  in  my  neighbourhood,  I  thought  I  saw 
sufficient  cause  for  the  want  of  flavour  in  the  fruit,  in  the  want  of  efficient 
foliage ;  and  appealing  to  experiment,  I  have  had  ample  reason  to  think 
my  opinions  well  founded. 

The  leaves  of  the  melon,  as  of  every  other  plant,  naturally  arrange 
themselves  so  as  to  present,  with  the  utmost  advantage,  their  upper 

*  See  above,  No.  XII.         f  Above,  Nos.  III.  and  IV.         £  Above,  No.  II. 


THEORY    OF    VEGETATION 

surfaces  to  the  light :  and  if,  by  any  means,  the  position  of  the  plant  is 
changed,  the  leaves,  as  long  as  they  are  young  and  vigorous,  make  efforts 
to  regain  their  proper  position.  But  the  extended  branches  of  the  melon 
plant,  particularly  under  glass,  are  slender  and  feeble ;  its  leaves  are 
broad  and  heavy,  and  its  leaf-stalks  long ;  so  that  if  the  leaves  be  once 
removed,  either  by  the  weight  of  water  from  the  watering-pot,  the  hand 
of  the  gardener  in  pruning  or  eradicating  weeds,  or  any  other  cause, 
from  their  proper  position,  they  never  regain  it ;  and  in  consequence,  a 
large  portion  of  that  foliage,  which  preceded,  or  was  formed  at  the  same 
period  with  the  blossoms,  and  which  nature  intended  to  generate  sap  to 
feed  the  fruit,  becomes  diseased  and  sickly,  and  consequently  out  of  office, 
before  the  fruit  acquires  maturity. 

To  remedy  this  defect,  I  placed  my  plants  at  greater  distances  from 
each  other  than  my  gardener  had  previously  done,  putting  a  single  plant 
under  each  light,  the  glass  of  which  was  six  feet  long  by  four  wide. 
The  beds  were  formed  of  a  sufficient  depth  of  rich  mould  to  ensure 
the  vigorous  growth  of  the  plant :  and  the  mould  was,'  as  usual,  covered 
with  brick-tiles,  over  which  the  branches  were  conducted  in  every 
direction,  so  as  to  present  the  largest  possible  width  of  foliage  to  the 
light.  Many  small  hooked  pegs,  such  as  the  slender  branches  of  the 
beech,  the  birch,  and  hazel,  readily  afford,  had  been  previously  provided; 
and  by  these,  which  passed  into  the  mould  of  the  bed,  between  the  tiles, 
the  branches  of  the  plants  were  secured  from  being  disturbed  from  their 
first  position.  The  leaves  were  also  held  erect,  and  at  an  equal  distance 
from  the  glass,  and  enabled,  if  slightly  moved  from  their  proper  position, 
to  regain  it. 

I,  however,  still  found  that  the  leaves  sustained  great  injury  from  the 
weight  of  the  water  falling  from  the  watering-pot :  and  I  therefore 
ordered  the  water  to  be  poured,  from  a  vessel  of  a  proper  construction, 
upon  the  brick-tiles,  between  the  leaves,  without  at  all  touching  them ; 
and  thus  managed,  I  had  the  pleasure  to  see,  that  the  foliage  remained 
erect  and  healthy.  The  fruit  also  grew  with  very  extraordinary  rapidity, 
ripened  in  an  unusually  short  time,  and  acquired  a  degree  of  perfection, 
which  I  had  never  previously  seen. 

As  soon  as  a  sufficient  quantity  of  fruit  (between  twenty  and  thirty 
pounds)  on  each  plant  is  set,  I  would  recommend  the  further  production 
of  foliage  to  be  prevented,  by  pinching  off  the  lateral  shoots  as  soon  as 
produced,  wherever  more  foliage  cannot  be  exposed  to  the  light.  No 
part  of  the  full-grown  leaves  should  ever  be  destroyed  before  the  fruit  is 
gathered  unless  they  injure  each  other,  by  being  too  much  crowded 


ILLUSTRATED    IN    THE    CULTURE    OF    THE    MELON.  193 

together ;  for  each  leaf,  when  full  grown,  however  distant  from  the  fruit, 
and  growing  on  a  distinct  branch  of  the  plant,  still  contributes  to  its 
support ;  and  hence  it  arises,  that  when  a  plant  has  as  great  a  number 
of  growing  fruit  upon  part  of  its  branches,  as  it  is  capable  of  feeding,  the 
blossoms  upon  other  branches,  which  extend  in  an  opposite  direction, 
prove  abortive. 

The  variety  of  melon,  which  I  exclusively  cultivate,  is  little  known  in 
this  country,  and  was  imported  from  Salonica  by  Mr.  Hawkins.  Its  form 
is  nearly  spherical,  when  the  fruit  is  most  perfect,  and  without  any 
depressions  upon  its  surface ;  its  colour  approaching  to  that  of  gold,  and 
its  flesh  perfectly  white.  It  requires  a  much  greater  state  of  maturity 
than  any  other  variety  of  its  species,  and  continues  to  improve  in  flavour 
and  richness,  till  it  becomes  externally  soft,  and  betrays  some  symptoms 
of  incipient  decay.  The  consistence  of  its  flesh  is  then  nearly  that  of  a 
water-melon,  and  it  is  so  sweet,  that  few  will  think  it  improved  by  the 
addition  of  sugar.  The  weight  of  a  good  melon  of  this  variety  is  about 
seven  pounds. 


XXII.— ON  THE    ADVANTAGES    OF   EMPLOYING   VEGETABLE    MATTER    AS 
MANURE  IN  A  FRESH  STATE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  January  6th,  1812.] 

WRITERS  upon  agriculture,  both  in  ancient  and  modern  times,  have 
dwelt  much  upon  the  advantages  of  collecting  large  quantities  of  vegetable 
matter  to  form  manure ;  whilst  scarcely  any  thing  has  been  written  upon 
the  state  of  decomposition,  in  which  decaying  vegetable  substances  can 
be  employed,  most  advantageously,  to  afford  food  to  living  plants.  Both 
the  farmer  and  gardener,  till  lately,  thought  that  such  manures  ought 
not  to  be  deposited  in  the  soil  till  putrefaction  had  nearly  destroyed  all 
organic  texture ;  and  this  opinion  is,  perhaps,  still  entertained  by  a 
majority  of  gardeners  ;  it  is,  however,  wholly  unfounded.  Carnivorous 
animals,  it  is  well  known,  receive  most  nutriment  from  the  flesh  of  other 
animals,  when  they  obtain  it  most  nearly  in  the  state  in  which  it  exists 
as  part  of  a  living  body  ;  and  the  experiments  I  shall  proceed  to  state, 
afford  evidence  of  considerable  weight,  that  many  vegetable  substances 
are  best  calculated  to  re-assume  an  organic  living  state,  when  they  are 
least  changed  and  decomposed  by  putrefaction. 

I  had  been  engaged,   in  the  year  1810,  in  some  experiments,  from 


194  ADVANTAGES    OF    EMPLOYING    VEGETABLE    MATTER 

which  I  hoped  to  obtain  new  varieties  of  the  plum  ;  but  only  one  of  the 
blossoms,  upon  which  I  had  operated,  escaped  the  excessive  severity  of 
the  frost  in  the  spring.  The  seed,  which  this  afforded,  having  been 
preserved  in  mould  during  the  winter,  was,  in  March,  placed  in  a  small 
garden-pot,  which  was  nearly  filled  with  the  living  leaves  and  roots  of 
grasses,  mixed  with  a  small  quantity  of  earth ;  and  this  was  sufficiently 
covered  with  a  layer  of  mould,  which  contained  the  roots  only  of  grasses, 
to  prevent,  in  a  great  measure,  the  growth  of  the  plants  which  were 
buried.  The  pot,  which  contained  about  one-sixteenth  of  a  square  foot 
of  mould  and  living  vegetable  matter,  was  placed  under  glass,  but  without 
artificial  heat,  and  the  plant  appeared  above  the  soil  in  the  end  of  April. 
It  was  three  times,  during  the  summer,  removed  into  a  larger  pot,  and 
each  time  supplied  with  the  same  matter  to  feed  upon  ;  and  in  the  end 
of  October  its  roots  occupied  about  the  space  of  one-third  of  a  square 
foot,  its  height  above  the  surface  of  the  mould  being  then  nine  feet 
seven  inches. 

In  the  beginning  of  June,  a  small  piece  of  ground  was  planted  with 
potatoes  of  an  early  variety,  and  in  some  rows  green  fern,  and  in  others 
nettles,  were  employed  instead  of  other  manure  ;  and,  subsequently,  as 
the  early  potatoes  were  taken  up  for  use,  their  tops  were  buried  in  rows 
in  the  same  manner,  and  potatoes  of  the  preceding  year  were  placed 
upon  them,  and  covered  in  the  usual  way.  The  days  being  then  long, 
the  ground  warm,  and  the  decomposing  green  leaves  and  stems  affording 
abundant  moisture,  the  plants  acquired  their  full  growth  in  an  unusually 
short  time,  and  afforded  an  abundant  produce  ;  and  the  remaining  part 
of  the  summer  proved  more  than  sufficient  to  mature  potatoes  of  an  early 
variety.  The  market-gardener  may,  probably,  employ  the  tops  of  his 
early  potatoes,  and  other  green  vegetable  substances,  in  this  way,  with 
much  advantage, 

In  these  experiments,  the  plum-stone  was  placed  to  vegetate  in  the 
turf  of  the  alluvial  soil  of  a  meadow,  and  the  potatoes  grew  in  ground 
which,  though  not  rich,  was  not  poor  ;  and,  therefore,  some  objections 
may  be  made  to  the  conclusions  I  am  disposed  to  draw  in  favour  of  recent 
vegetable  substances,  as  manures.  The  following  experiment  is,  however, 
I  think,  decisive. 

I  received,  from  a  neighbouring  farmer,  a  field  naturally  barren,  and 
so  much  exhausted  by  ill  management,  that  the  two  preceding  crops  had 
not  returned  a  quantity  of  corn  equal  to  that  which  had  been  sowed  upon 
it.  An  adjoining  plantation  afforded  me  a  large  quantity  of  fern,  which 
I  proposed  to  employ  as  manure  for  a  crop  of  turnips.  This  was  cut 


AS    MANURE    IN    A    FRESH    STATE.  1,95 

between  the  10th  and  20th  of  June;  but  as  the  small  cotyledons  of  the 
turnip-seed  afford  little  to  feed  the  young  plant ;  and  as  the  soil,  owing 
to  its  extreme  poverty,  could  not  yield  much  nutriment,  I  thought  it 
necessary  to  place  the  fern  a  few  days  in  a  heap,  to  ferment  sufficiently 
to  destroy  life  in  it,  and  to  produce  an  exudation  of  its  juices ;  and  it 
was  then  committed,  in  rows,  to  the  soil,  and  the  turnip-seed  deposited, 
with  a  drilling  machine,  over  it. 

Some  adjoining  rows  were  manured  with  the  black  vegetable  mould 
obtained  from  the  site  of  an  old  wood  pile,  mixed  with  the  slender 
branches  of  trees  in  every  stage  of  decomposition,  the  quantity  placed  in 
each  row  appearing  to  me  to  exceed,  more  than  four  times,  the  amount 
of  the  vegetable  mould,  which  the  green  fern,  if  equally  decomposed, 
would  have  yielded.  The  crop  succeeded  in  both  cases ;  but  the  plants 
upon  the  green  fern  grew  with  greatly  more  rapidity  than  the  others, 
and  even  than  those  which  had  been  manured  with  the  produce  of  my 
fold  and  stable -yard,  and  were  distinguishable,  in  the  autumn,  from  the 
plants  in  every  other  part  of  the  field,  by  the  deeper  shade  of  their 
foliage. 

I  had  made,  in  preceding  years,  many  similar  experiments  with  small 
trees  (particularly  those  of  the  mulberry  when  bearing  fruit  in  pots),  with 
similar  results :  but  I  think  it  unnecessary  to  trespass  on  the  time  of  the 
Society  by  stating  these  experiments,  conceiving  those  I  have  mentioned 
to  be  sufficient  to  show  that  any  given  quantity  of  vegetable  matter  can 
generally  be  employed,  in  its  recent  and  organised  state,  with  much  more 
advantage  than  when  it  has  been  decomposed,  and  no  inconsiderable 
part  of  its  component  parts  has  been  dissipated  and  lost,  during  the 
progress  of  the  putrefactive  fermentation. 


XXIIL— ON  FACILITATING  THE  EMISSION  OF  ROOTS  FROM  LAYERS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  4th>  1812.] 

IT  is  my  custom,  annually,  to  repeat  every  experiment  that  occurs  to 
me,  from  which  I  have  reason  to  expect  information  either  in  opposition 
to,  or  in  favour  of,  the  opinions  I  have  advanced  respecting  the  genera- 
tion and  motion  of  the  sap  in  trees ;  and  one  of  these  experiments 
appearing  to  point  out  an  improvement  in  the  propagation  of  such  trees  by 
layering,  as  do  not  readily  emit  roots  by  that  process,  I  send  the  following 
statement,  under  the  hope  that  it  may  be  acceptable  to  the  Horticultural 
Society. 

o2 


196  ON    FACILITATING    THE    EMISSION 

I  have  cited,  in  a  former  communication*,  a  part  of  the  evidence  upon 
which  I  have  inferred  that  the  sap  of  trees  descends  from  their  leaves 
through  the  bark  ;  and  I  shall  here  only  observe,  in  support  of  that 
opinion,  that  if  a  piece  of  bark  be  everywhere  detached  from  the  tree, 
except  at  its  upper  end,  it  will  deposit,  under  proper  management,  as 
much,  or  nearly  as  much  wood,  upon  its  interior  surface,  as  it  will  if  it 
retain  its  natural  position ;  and  that  the  sap  which  generates  the  wood, 
deposited  in  the  preceding  circumstances,  must  descend  through  the 
•bark,  as  it  cannot  be  derived  from  any  other  source. 

When  a  layer  is  prepared,  and  deposited  in  the  ground,  the  progress 
of  the  sap,  in  its  descent  towards  the  original  roots,  is  intercepted  upon 
the  side  where  the  partially  detached  part,  or  tongue,  of  the  layer  is 
divided  from  the  branch ;  and  this  intercepted  sap  is,  in  consequence, 
generally  soon  employed  in  the  formation  of  new  roots.  But  there  are 
many  species  of  trees  which  do  not  readily  emit  roots  by  this  mode  of 
treatment ;  and  I  suspected  that,  wherever  roots  are  not  emitted  by 
layers,  the  sap,  which  descends  from  the  leaves,  must  escape  almost  wholly 
through  the  remaining  portion  of  bark,  which  connects  the  layer  with  the 
parent  plant.  I  therefore  attempted,  in  the  last  and  the  preceding 
spring,  to  accelerate  the  emission  of  roots  by  layers  of  trees  of  different 
species  which  do  not  really  emit  roots,  by  the  following  means,  having 
detached  the  tongue  of  the  layers  from  the  branches  in  the  usual 
manner. 

Soon  after  Midsummer,  when  the  leaves  upon  the  layers  had  acquired 
their  full  growth,  and  were,  according  to  my  hypothesis,  in  the  act  of 
generating  the  true  sap  of  the  plant,  the  layers  \vere  taken  out  of  the 
soil,  and  I  found  that  those  of  several  species  of  trees  did  not  indicate 
any  disposition  to  generate  roots,  a  small  portion  of  cellular  bark  only 
having  issued  from  the  interior  surface  of  the  bark  in  the  wounded  parts. 
I  therefore  took  measures  to  prevent  the  return  of  the  sap  through  the 
bark,  from  the  layers  to  the  parent  trees,  by  making,  round  each  branch, 
two  circular  incisions  through  the  bark,  immediately  above  the  space 
where  the  tongue  of  the  layer  had  been  detached  ;  and  the  bark  between 
these  incisions,  which  were  about  twice  the  diameter  of  the  branch  apart, 
was  taken  off.  The  surface  of  the  decorticated  spaces  was  then  scraped 
with  a  knife,  to  prevent  the  reproduction  of  the  bark,  and  the  layers  were 
recommitted  to  the  soil  ;  and  at  the  end  of  a  month  I  had  the  pleasure 
to  observe  that  roots  had  been  abundantly  emitted  by  every  one.  In 
other  instances,  I  obtained  the  same  results  by  simply  scraping  off,  at  the 

*  Page  190. 


OF    ROOTS    FROM    LAYERS.  197 

same  season,  a  portion  of  the  bark,  immediately  at  the  base  of  the  tongue 
of  the  layers,  without  taking  them  out  of  the  ground. 

By  the  preceding  mode  of  management,  the  ascending  fluid  is  permitted 
to  pass  freely  into  the  layer  to  promote  its  growth,  and  to  return  till  the 
period  arrives  at  which  layers  generally  begin  to  emit  roots ;  the  return 
of  the  sap  through  the  bark  is  then  interrupted,  and  roots  are,  in  conse- 
quence, emitted  ;  and  I  entertain  little  doubt  that  good  plants  of  trees, 
of  almost  every  species,  may  be  thus  obtained  at  the  end  of  a  single  season. 
I  wish  it,  however,  to  be  understood,  that  my  experiments  have  been 
confined  to  comparatively  few  species  of  trees  ;  and  that  I  am  not  much 
in  the  habit  of  cultivating  trees  of  difficult  propagation. 


XXIV.— ON  THE    PREVENTION  OF   THE    DISEASE    CALLED   THE    CURL  IN 

THE  POTATOE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  '2nd,  lf!13.] 

THE  rough  and  uneven  surface  of  the  leaf,  which  in  excess,  indicates, 
and  indeed  constitutes,  the  disease  called  the  curl  in  the  potatoe,  appears 
to  exist  in,  and  to  form  an  essential  characteristic  of,  every  good  variety  of 
that  plant ;  for  I  have  never  found  a  single  variety,  with  perfectly  smooth 
and  polished  leaves,  which  possessed  any  degree  of  excellence  ;  and  I 
have  endeavoured  to  prove,  in  a  former  communication  *,  that  the 
rough  and  crumpled  state  of  the  leaf  probably  originates  in  the  pre- 
ternaturally  inspissated  state  of  the  fluid,  in  the  firm  and  farinaceous 
potatoe.  Those  varieties  are,  however,  generally  most  productive  and 
grow  with  the  greatest  luxuriance,  of  which  the  leaves  are  smooth  and 
polished ;  and  this  point  tends  to  prove,  that  the  smooth  leaf  is  a  more 
perfect  and  efficient  organ  than  the  rough  one ;  the  latter  indicating 
some  degree  of  approximation  to  disease. 

I  have  stated,  in  another  paper  f ,  that  I  obtained  a  second  crop  of 
potatoes  by  planting  those  of  an  early  variety  in  the  same  soil  from 
which  a  crop  of  the  same  variety  had  been  taken,  in  the  month  of 
July ;  and  that  I  had  employed,  with  success,  the  tops  of  those  taken 
up,  with  green  fern  and  nettles,  as  manure.  But  I  found  the  tubers 
produced  by  those  last  planted  to  be  much  more  soft  and  watery, 
when  boiled,  than  others  of  the  same  variety,  and  consequently  much 
inferior  in  value  for  every  culinary  purpose  ;  and  therefore,  these  were 

*  See  page  185.  f  See  page  194. 


198  ON    THE    PREVENTION    OF 

kept  for  the  purpose  of  planting  in  the  last  spring.  1  inferred,  con- 
sistently with  the  hypothesis  I  adduced  in  the  paper  last  quoted, 
that  the  organisable  matter  these  contained,  being  in  a  less  firm  and 
concrete  state,  would  prove  more  disposable,  and  that  I  might  therefore 
expect,  in  the  succeeding  season,  plants  of  stronger  growth,  and  more 
smooth  and  perfect  foliage.  The  result,  in  every  respect,  coincided  with 
my  expectations;  the  plants  presented  the  appearance  of  a  different 
variety,  and  afforded  a  more  abundant  crop  and  larger  tubers  than  I  had 
ever  obtained  from  the  same  variety. 

This  experiment  was  confined  to  a  single  very  early  kind,  which  had 
previously  produced  partially  curled  leaves ;  but  I  imagine  the  same  mode 
of  management  will  prove  equally  advantageous  with  other  varieties  which 
show  similar  indications  of  incipient  disease ;  and  as  every  improvement 
in  the  culture  of  this  plant,  which  can  add  to  the  produce  without 
increasing  the  ex  pence,  is  of  importance  to  the  public,  I  submit  the  pre- 
ceding account  to  the  Horticultural  Society. 

A  very  respectable  writer,  in  the  Memoirs  of  the  Caledonian  Horticul- 
tural Society*,  Mr.  Dickson,  has  advanced  an  hypothesis,  somewhat  dif- 
ferent from  mine,  respecting  the  curl  in  the  potatoe :  he  conceives  it  to 
originate  in  debility  arising  from  the  too  great  ripeness  of  the  tubers,  and 
in  the  parent  plant  having  too  much  expended  itself  in  affording  blossoms 
and  seeds,  as  well  as  tubers.  But  I  can  scarcely  accede  to  this  hypothesis, 
because  I  do  not  think  it  probable  that  a  plant,  which  is  a  native  of 
Virginia,  can  be  over-ripened  in  the  climate  of  Scotland ;  and  because 
those  varieties,  which  never  afford  either  blossoms  or  seeds,  have,  in  my 
garden,  been  quite  as  subject  to  that  disease  as  others.  Mr.  Dickson  has 
stated  the  curious  fact  (and  I  do  not  entertain  the  slightest  doubt  of  his 
perfect  correctness),  that  a  cutting  taken  from  the  extremity,  which  is 
most  firm  and  farinaceous,  of  a  long,  or  kidney-shaped  potatoe,  will 
afford  diseased  plants,  whilst  another  cutting,  taken  from  the  opposite 
end  of  the  same  potatoe,  will  produce  perfectly  healthy  plants  ;  but  I  do 
not  attribute  this  to  the  greater  maturity  of  the  buds  at  the  extremity, 
than  at  the  opposite  end,  for  those  nearest  the  parent  plant  are  really  the 
oldest,  the  tuber  being  formed  by  a  branch,  which  has  expanded  itself 
laterally,  instead  of  having  extended  itself  longitudinally.  Its  buds  are 
in  consequence  arranged  as  they  would  have  been  upon  the  elongated 
branch ;  and  every  tuber,  in  its  incipient  state  of  formation,  will  extend 
itself  into  a  branch,  as  I  have  shown  in  the  Philosophical  Transactions 
for  1809f,  provided  the  plant,  to  which  it  belongs,  be  cut  off  close  to  the 

*  See  Vol.  I.  p.  50.  f  See  above,  p.  157. 


THE  CURL  IN  THE  POTATOE.  199 

ground,  and  the  current  of  ascending  sap  be  in  consequence  diverted 
into,  and  through  the  tubers.  Mr.  Dickson,  and  myself,  however,  per- 
fectly agree  that  a  tuber,  or  part  of  one,  which  is  soft  and  aqueous, 
affords  a  better  plant  than  one  which  is  firm  and  farinaceous ;  and  the 
trifling  difference  of  opinion  between  us,  being  purely  hypothetical,  is  of 
no  importance. 

I  observed  that  the  crops  of  potatoes,  which  I  raised  from  the  late 
ripened  tubers  above-mentioned,  were  not  quite  so  early  as  others  of  the 
same  variety  ;  but  I  attribute  this  variation  in  the  periods  of  the  maturity 
of  the  crops  solely  to  different  degrees  of  luxuriance  in  the  plants,  and  to 
the  increased  size  of  the  tubers  in  the  one.  In  quality,  the  produce  of 
both  was  the  same. 


XXV.— ON    THE   EARLY   PUBERTY    OF  THE    PEACH-TREE, 
[Read  before  the  HORTICULTURAL  SOCIETY,  March  2,  1813.] 

IT  was  asserted,  a  few  years  ago,  by  a  gentleman  who  had  held  an 
official  situation  in  New  South  Wales,.that  a  seedling  peach-tree  in  that 
climate  had  produced  fruit  under  his  care  when  it  was  only  sixteen 
months  old,  without  having  been  grafted.  The  silence  of  the  French 
writers  upon  gardening,  respecting  this  earliness  of  puberty  in  the  peach- 
tree,  and  the  well-known  circumstance  that  several  years  generally 
elapse  between  the  period  when  a  tree  first  springs  from  seed,  and  that 
in  which  it  becomes  capable  of  producing  blossoms  and  fruit,  appear  ta 
have  induced  a  general  disbelief  of  this  account,  which  was  mentioned  to- 
me, by  several  of  my  friends,  as  an  extravagant  and  ridiculous  falsehood ; 
and  probably  I  should  too  readily  have  coincided  with  them  in  opinion,  if 
I  had  not  previously  noticed  several  peculiar  circumstances  in  the  habits 
of  seedling  peach-trees.  I  had  observed  that  such  trees  continued  to 
grow  as  long  as  the  weather  continued  favourable ;  and  that  their  leaves, 
in  almost  every  succeeding  month,  assumed  a  more  mature  and  improved 
character;  so  that  at  the  end  of  the  first  autumn,  the  leaves  of  the 
parent  and  seedling  trees  did  not  differ  much  from  each  other ;  and 
such  seedling  trees,  though  they  were  retained  in  small  pots  till  they 
were  eighteen  months  old,  and  subsequently  trained  against  a  wall  in  the 
open  air,  and  in  a  cold  and  late  situation,  produced  fruit  when  only  three 
years  old. 

I  therefore  thought  it  not  improbable  that,  with  the  aid  of  glass  and 


200  ON  THE  EARLY  PUBERTY  OF  THE  PEACH-TREE. 

artificial  heat,  I  might  succeed  in  obtaining  fruit  from  trees  of  two  years 
old  ;  and  not  impossible  that,  by  a  peculiar  mode  of  pruning,  I  might 
obtain  fruit  from  yearling  trees,  though  the  want  of  sunshine  in  our 
climate  did  not  permit  me  to  entertain  very  sanguine  hopes  of  success. 

Some  peach  stones,  which  were  the  produce  of  trees  upon  which  I 
had  made  experiments  in  the  year  1811,  with  the  hope  of  obtaining 
early  varieties  of  nectarines,  were  intended  to  have  been  placed  in 
pots  in  a  hot-house,  in  the  beginning  of  January  1812  ;  and  one  of  my 
friends  (I  do  not  myself  possess  a  hot-house)  had  offered  me  the  use  of 
his  house  to  accelerate  the  germination  and  growth  of  the  seedling 
plants.  I,  however,  found  the  hot-house  of  my  friend  so  much  infested 
with  insects  of  various  kinds  that  I  did  not  choose  to  risk  my  plants  in 
it ;  and  the  seeds  in  consequence  were  not  subjected  to  the  influence  of 
artificial  heat  till  the  middle  of  February,  when  I  began  to  make  fires  in 
my  vinery.  The  plants  appeared  above  the  soil  early  in  March  ;  and 
they  were  kept  under  glass  during  the  whole  summer  and  autumn ;  but 
without  any  artificial  heat  being  applied  after  the  end  of  May. 

Conceiving  that  nature,  in  placing  the  age  of  puberty,  in  trees,  so 
distant  from  the  period  in  which  they  spring  from  seed,  has  intended 
chiefly  to  afford  the  plant,  in  this  interval,  the  means  of  collecting  a 
considerable  store  of  organisable  matter,  before  the  expenditure  of  its 
sap  commences  in  the  production  of  blossoms  and  fruit,  I  adopted  the 
mode  of  pruning  and  culture  which,  consistently  with  my  theoretical 
opinions,  appeared  best  calculated  to  promote  that  object.  The  leaves 
being  the  organs  on  which  alone  I  believe  the  true  sap  of  the  tree  to  be 
generated,  as  many  lateral  shoots  were  suffered  to  remain  upon  each 
plant,  as  could  present  their  foliage  to  the  light  without  injuriously 
interfering  with  each  other ;  and  these  were  shortened,  whilst  very 
young,  to  the  fourth  or  fifth  leaf;  and  the  buds  in  the  axillse  of  these 
leaves  were  destroyed  as  soon  as  they  became  visible ;  so  that  whatever 
portion  of  sap  these  leaves  might  generate,  none  might  be  uselessly 
expended.  I  had  previously  proved  that  leaves,  under  these  circum- 
stances, will  promote  the  growth  of  the  stem  between  themselves  and  the 
ground ;  so  that  any  degree  of  taperness  may  be  given  to  the  stem, 
almost  as  accurately  by  the  gardener,  in  proportioning  the  quantity  and 
position  of  the  foliage,  as  it  can  be  subsequently  given  to  the  lifeless  wood 
by  the  plane  of  the  artificer ;  and  I  calculated  that  the  true  sap,  which 
would  be  generated  by  the  leaves  upon  the  lower  parts  of  the  stem,  and 
lateral  shoots,  would  be  employed  in  feeding  the  roots ;  whilst  a  portion 
of  that,  which  would  be  generated  by  the  foliage  near  the  summit  of  the 


ON  THE  EARLY  PUBERTY  OF  THE  PEACH-TREE.  201 

trees,  might  there  contribute  to  the  formation  of  fruit  buds.  The  lateral 
shoots  which  were  emitted  near  the  tops  of  the  young  trees,  when  these 
had  attained  the  height  of  seven  or  eight  feet,  were  in  consequence  only 
shortened,  the  buds  upon  them  being  left,  in  the  hope  that  some  of  them 
would  be  converted  into  blossoms. 

The  pots  were  filled  with  the  green  turf  of  the  alluvial  soil  of  a  rich 
meadow,  which  substance  I  had  previously  employed  with  much  success 
in  similar  experiments ;  and  the  pots  were  three  times  changed  during 
the  summer,  and  new  portions  of  living  turf  added  at  the  same  periods. 

The  summer,  however,  proved  so  cold  and  cloudy,  that  I  relinquished 
all  hopes  of  success,  proposing  to  repeat  the  experiment  under  less 
unfavourable  circumstances;  and  in  consequence  the  artificial  heat, 
which  I  had  intended  to  employ  in  Autumn,  was  not  applied.  I  had, 
nevertheless,  the  unexpected  pleasure  to  observe,  late  in  the  autumn, 
that  three  of  the  seven  plants  which  had  been  the  subjects  of  my  experi- 
ment, had  formed  blossom  buds ;  and  these  buds  have  subsequently 
presented  so  vigorous  and  healthy  a  character,  that  I  do  not  entertain 
any  doubt  of  their  being  capable  of  affording  fruit. 

The  narrative  of  the  planter  of  New  South  Wales  was  therefore,  I 
conclude,  perfectly  correct ;  and  I  think  it  not  improbable,  that  by 
shortening  the  lateral  branches  of  his  young  plant,  to  give  it  a  proper 
form,  he  incidentally  adopted  very  nearly  the  same  mode  of  pruning, 
which  theoretical  opinions  pointed  out  to  me  as  the  best. 


XXVI.— ON  THE  CULTURE  OF  THE  PEAR-TREE. 
[Read  before  the   HORTICULTURAL    SOCIETY,    May  18th,   1813.] 

THE  pear-tree  exercises  the  patience  of  the  planter  during  a  longer 
period  before  it  affords  fruit,  than  any  other  grafted  tree  which  finds  a 
place  in  our  gardens ;  and  though  it  is  subsequently  very  long-lived,  it 
generally,  when  trained  to  a  wall,  becomes  in  a  few  years  unproductive 
of  fruit,  except  at  the  extremities  of  its  lateral  branches.  Both  these 
defects  are,  however,  I  have  good  reason  to  believe,  the  result  of 
improper  management ;  for  I  have  lately  succeeded  most  perfectly  in 
rendering  my  old  trees  very  productive  in  every  part ;  and  my  young 
trees  have  almost  always  afforded  fruit  the  second  year  after  being 
grafted  ;  and  none  have  remained  barren  beyond  the  third  year. 

In  detailing  the  mode  of  pruning  and  culture  I  have  adopted,  I  shall 


202  ON    THE    CULTURE    OF    THE    PEAR-TREE. 

probably  more  easily  render  myself  intelligible,  by  describing  accurately 
the  management  of  a  single  tree  of  each. 

An  old  St.  Germain  pear-tree,  of  the  spurious  kind,  had  been  trained 
in  the  fan  form,  against  a  north-west  wall  in  my  garden,  and  the  central 
branches,  as  usually  happens  in  old  trees  thus  trained,  had  long  reached 
the  top  of  the  wall,  and  had  become  wholly  unproductive.  The  other 
branches  afforded  but  very  little  fruit,  and  that  never  acquiring  maturity, 
was  consequently  of  no  value ;  so  that  it  was  necessary  to  change  the 
variety,  as  well  as  to  render  the  tree  productive. 

To  attain  these  purposes,  every  branch  which  did  not  want  at  least 
twenty  degrees  of  being  perpendicular,  was  taken  out  at  its  base ;  and 
the  spurs  upon  every  other  branch,  which  I  intended  to  retain,  were 
taken  off  closely  with  the  saw  and  chisel.  Into  these  branches,  at  their 
subdivisions,  grafts  were  inserted  at  different  distances  from  the  root, 
and  some  so  near  the  extremities  of  the  branches,  that  the  tree  extended 
as  widely  in  the  autumn,  after  it  was  grafted,  as  it  did  in  the  preced- 
ing year.  The  grafts  were  also  so  disposed,  that  every  part  of  the 
space  the  tree  previously  covered,  was  equally  well  supplied  with  young 
wood. 

As  soon,  in  the  succeeding  summer,  as  the  young  shoots  had  attained 
sufficient  length,  they  were  trained  almost  perpendicularly  downwards, 
between  the  larger  branches,  and  the  wall,  to  which  they  were  nailed. 
The  most  perpendicular  remaining  branch  upon  each  side,  was  grafted 
about  four  feet  below  the  top  of  the  wall,  which  is  twelve  feet  high  ;  and 
the  young  shoots,  which  the  grafts  upon  these  afforded,  were  trained 
inwards,  and  bent  down  to  occupy  the  space  from  which  the  old  central 
branches  had  been  taken  away ;  and  therefore  very  little  vacant  space 
anywhere  remained  in  the  end  of  the  first  autumn.  A  few  blossoms, 
but  not  any  fruit,  were  produced  by  several  of  the  grafts  in  the  succeed- 
ing spring ;  but  in  the  following  year,  and  subsequently,  I  have  had 
abundant  crops,  equally  dispersed  over  every  part  of  the  tree ;  and  I 
have  scarcely  ever  seen  such  an  exuberance  of  blossom  as  this  tree 
presents  in  the  present  spring.  Grafts  of  eight  different  kinds  of  pears 
had  been  inserted,  and  all  afforded  fruit,  and  almost  in  equal  abundance. 
By  this  mode  of  training,  the  bearing  branches,  being  small  and  short, 
may  be  changed  every  three  or  four  years,  till  the  tree  is  a  century  old, 
without  the  loss  of  a  single  crop ;  and  the  central  part,  which  is  unpro- 
ductive in  every  other  mode  of  training,  becomes  the  most  fruitful. 
I  proceed  to  the  management  of  young  trees. 

A  young  pear  stock,  which  had  two  lateral  branches  upon  each  side, 


ON  THE  CULTURE  OF  THE  PEAR-TREE.  203 

and  was  about  six  feet  high,  was  planted  against  a  wall  early  in  the 
spring  of  1810;  and  it  was  grafted  in  each  of  its  lateral  branches,  two 
of  which  sprang  out  of  the  stem  about  four  feet  from  the  ground,  and  the 
others  at  its  summit,  in  the  following  year.  The  shoots  these  grafts 
produced,  when  about  a  foot  long,  were  trained  downwards,  as  in  the 
preceding  experiment,  the  undermost  nearly  perpendicularly,  and  the 
uppermost  just  below  the  horizontal  line,  placing  them  at  such  distances, 
that  the  leaves  of  one  shoot  did  not  at  all  shade  those  of  another.  In  the 
next  year,  the  same  mode  of  training  was  continued,  and  in  the  following, 
that  is  the  last  year,  I  obtained  an  abundant  crop  of  fruit,  and  the  tree 
is  again  heavily  loaded  with  blossoms. 

This  mode  of  training  was  first  applied  to  the  Aston-Town  pear,  which 
rarely  produces  fruit  till  six  or  seven  years  after  the  trees  have  been 
grafted  ;  and  from  this  variety,  and  the  colmar,  I  have  not  obtained  fruit 
till  the  grafts  have  been  three  years  old. 

In  the  future  treatment  of  my  young  pear-trees  it  is  my  intention  to 
give  them  very  nearly  the  form  of  the  old  tree  I  have  described,  in  every 
respect,  except  that  these  will  necessarily  stand  upon  larger  stems,  which 
I  think  advantageous :  and  I  shall  not  permit  the  existence  of  so  great  a 
number  of  large  lateral  branches.  In  both  cases  the  bearing  wood  will 
depend  wholly  beneath  the  large  branches  which  feed  it ;  for  it  is  the 
influence  of  gravitation  upon  the  sap  which  occasions  the  early  and 
exuberant  produce  of  fruit. 

I  scarcely  need  add,  that  where,  in  old  trees,  it  is  not  meant  to  change 
the  variety,  nothing  more  will  be  necessary  than  to  take  off  wholly  the 
spurs  and  supernumerary  large  branches,  leaving  every  blossom  which 
grows  near  the  end  of  the  remaining  branches,  or  that  the  length  of  the 
dependent  bearing  wood  must  be  different  in  different  varieties.  The 
Crassane,  the  Colmar,  and  Aston-Town,  will  require  the  greatest,  and 
the  St.  Germain  probably  the  least  length. 


204 


XXVII.— ON   THE    PREVENTION   OF   MILDEW    IN    PARTICULAR    CASES. 
[Read  before  the  HORTICULTURAL  SOCIETY,  May  4,  1813.] 

THE  little  pamphlet  upon  the  rust,  or  mildew,  of  wheat,  for  which  the 
public  are  indebted  to  the  patriotic  exertions  of  the  venerable  President 
of  the  Royal  Society,  affords  much  evidence  in  proof  that  this  disease 
originates  in  a  minute  species  of  parasitical  fungus,  which  is  propagated, 
like  other  plants,  by  seeds  ;  and  the  evidence  adduced  would,  I  think, 
be  sufficient  to  remove  every  doubt  upon  the  subject,  were  the  means 
ascertained  by  which  the  seeds  of  this  species  of  fungus  are  conveyed 
from  the  wheat-plants  of  one  season  to  those  of  the  succeeding  year. 
This,  however,  has  not  yet  been  done ;  and  therefore  some  persons  still 
retain  an  opinion  that  the  mildew  of  wheat  consists  only  of  preternatural 
processes,  which  spring  from  a  diseased  action  of  the  powers  of  life  in  the 
plants  themselves. 

An  hypothesis,  which  differs  little  from  this,  has  been  published  in  the 
present  year  respecting  the  dry-rot  (Boletus  lacrymans)  of  timber  *.  It  is 
contended  that  the  different  kinds  of  fungus,  which  appear  upon  decaying 
timber  of  different  species,  are  produced  by  the  remaining  powers  of  life 
in  the  sap  of  the  unseasoned  wood  ;  and  that  the  same  kind  of  living 
organisable  matter,  which,  whilst  its  powers  remained  perfect,  would  have 
generated  an  oak-branch,  will,  when  debilitated,  give  existence  to  a 
species  of  fungus.  But,  if  this  power  exists,  and  becomes  capable,  during 
its  rapid  declension,  of  deviating  so  widely  from  its  original  mode  of 
action,  the  species  of  fungus  it  would  produce  might  be  expected  to 
become  successively  more  feeble  and  diminutive  ;  whereas  the  most  robust 
and  gigantic  of  the  whole  genus,  the  Boletus  squamosus.  springs  from  wood 
when  that  is  in  its  last  stage  of  decay;  and  the  best  known,  and  the 
most  valuable  species  to  mankind,  of  this  tribe  of  plants,  the  common 
mushroom,  appears  as  obviously  to  spring  from  horse-dung,  under 
favourable  circumstances,  as  any  species  of  the  same  tribe  appears  to 
spring  from  decomposing  wood,  without  the  previous  presence  of  seeds  f. 
Yet  it  can  scarcely  be  contended  that  any  vital  powers,  capable  of 
arranging  the  delicate  organisation  of  a  mushroom,  can  exist  in  a  horse- 
dung  ;  and  the  admission  of  any  such  power  would  surely  lead  to  the 
most  extravagant  conclusions.  For  if  a  mass  of  horse-dung  can  generate 
a  mushroom,  it  can  scarcely  be  denied  that  a  mass  of  animal  matter,  an 

*  Quarterly  Review,  Vol.  VII.  page  33. 
t  See  Nicol's  Forcing,  Fruit  and  Kitchen  Gardener,  4th  edition,  page  119. 


ON    THE    PREVENTION    OF    MILDEW    IN    PARTICULAR    CASES.  205 

old  cheese,  may  generate  a  mite ;  and  if  the  organs  of  a  mite  can  be 
thus  formed,  there  could  be  little  difficulty  in  believing  that  a  larger  mass 
of  decomposing  animal  matter  might  generate  an  elephant,  or  a  man. 

The  hypothesis  therefore  which  supposes  the  various  species  of  fungus 
to  spring  from  seeds,  appears  to  me  much  the  least  objectionable ;  and 
if  the  minute  bodies,  which  are  supposed  to  be  the  seeds  of  these  plants, 
be  really  such,  it  will  not  be  difficult  to  show  that  these  are  sufficiently 
numerous  to  account,  to  a  great  extent,  for  the  ubiquity  of  the  plants  they 
are  supposed  to  produce ;  particularly  as  such  apparent  seeds,  owing  to  their 
excessive  lightness,  are  capable  of  being  everywhere  dispersed  by  winds. 

A  few  vears  ago  I  raised  some  mushrooms  under  glass  with  the  intention 
of  collecting  and  subsequently  raising  mushrooms  from  the  seeds  they 
might  produce ;  and  I  then  endeavoured  to  ascertain  the  number  which 
would  be  afforded  by  a  single  fructification ;  for  a  mushroom  appears  to 
be  nothing  more  than  a  fructification  of  the  plant,  though  it  is  generally 
spoken  of  as  the  plant  itself.  I  placed  thin  plates  of  talc  under  a  very 
large  mushroom  at  the  period  when  the  minute  globular  bodies,  which 
are  supposed  to  be  the  seeds,  first  began  to  be  disengaged  from  its  gills ; 
and  I  endeavoured  to  count  the  number  which  fell  during  each  successive 
hour,  within  the  narrow  field  of  a  very  powerful  lens.  The  labour  to  my 
eyes  was,  however,  so  severe,  that  I  was  unable  to  count  with  any 
considerable  degree  of  accuracy ;  but  the  number  which  fell  from  a  single 
mushroom,  within  the  succeeding  ninety-six  hours,  exceeded,  upon  the 
lowest  calculation  I  could  make,  two  hundred  and  fifty  millions.  I 
endeavoured  to  raise  mushrooms  from  these  seeds,  but  I  failed  to  obtain 
any  decisive  results ;  for  though  I  readily  procured  mushroom  spawn  by 
mixing  such  seeds  with  unfermented  horse-dung,  I  also  obtained  it  in 
equal  abundance,  in  some  instances,  where  I  had  not  introduced  any  seeds. 

Immense  as  the  number  of  seeds  produced  by  a  single  mushroom 
appears,  it  probably  is  not  much  greater  than  that  which  a  single  plant 
of  mildewed  wheat  would  afford  ;  and,  according  to  this  calculation,  a 
single  acre  of  mildewed  wheat  would  probably  afford  seeds  sufficient  to 
communicate  disease  to  every  acre  of  wheat  in  the  British  empire,  under 
circumstances  favourable  to  the  growth  of  the  fungus ;  and  I  have  never 
seen  a  single  acre  of  wheat,  since  the  publication  of  Sir  Joseph  Banks's 
pamphlet,  so  free  from  mildew  but  that  it  would  have  afforded  seeds 
enough  amply  to  supply  the  adjoining  hundred  acres.  There  is  also 
reason  to  believe  that  the  berberry-tree  communicates  this  disease  to 
wheat  ;  and  I  have  also  often  noticed  a  similar  apparent  parasitical 
fungus  upon  the  straws  of  the  couch-grass,  in  the  hedges  of  corn-fields. 


206  ON    THE    PREVENTION    OF    MILDEW    IN    PARTICULAR    CASES. 

Neither  the  mildew  of  wheat,  nor  any  other  kind,  can  however  I 
think,  be  communicated  from  the  leaves  and  stems  of  one  plant  imme- 
diately to  those  of  another  :  very  numerous  attempts  made  by  myself  to 
succeed  in  experiments  of  this  kind  having,  I  believe,  proved  wholly 
abortive  ;  though  I  once  fancied  that  I  had  succeeded  in  two  or  three 
instances.  I  am,  therefore,  much  inclined  to  believe  that  the  parasitical 
fungus,  which  occasions  every  disease  of  this  kind,  enters  the  plant,  in  the 
first  instance,  by  its  roots,  and  though  it  may  probably  be  transferred 
with  the  graft,  and  possibly  by  a  bud,  from  one  fruit-tree  to  another;  and 
if  the  seeds  be  capable,  like  those  of  many  other  plants,  of  remaining 
sound  a  considerable  time  beneath  the  soil,  or  in  other  situations,  till 
circumstances,  which  are  favourable  to  their  growth,  occur,  the  abundant 
appearance  of  the  mildew,  or  mushrooms,  may  be  accounted  for  without 
supposing  them  to  be  generated  wholly  by  the  bodies  from  which  they 
immediately  spring. 

I  shall  not  trespass  upon  the  time  of  the  Horticultural  Society  by 
dwelling  longer  upon  the  primary  cause  of  the  various  diseases  which  are 
comprehended  under  the  name  of  mildew ;  but  shall  proceed  to  the 
immediate  object  of  the  present  memoir,  which  is  to  point  out  the  means 
by  which  the  injurious  effects  of  the  common  white  mildew  may  be,  in 
particular  cases,  prevented. 

The  secondary  and  immediate  causes  of  this  disease,  and  of  its  con- 
geners, have  long  appeared  to  me  to  be  the  want  of  a  sufficient  supply  of 
moisture  from  the  soil  with  excess  of  humidity  in  the  air,  particularly 
if  the  plants  be  exposed  to  a  temperature  below  that  to  which  they  have 
been  accustomed.  If  damp  and  cold  weather  in  July  succeed  that  which 
has  been  warm  and  bright,  without  the  intervention  of  sufficient  rain  to 
moisten  the  ground  to  some  depth,  the  wheat  crop  is  generally  much 
injured  by  mildew.  I  suspect  that,  in  such  cases,  an  injurious  absorption 
of  moisture,  by  the  leaves  and  stems  of  the  wheat  plants,  takes  place ; 
and  I  have  proved,  that  under  similar  circumstances  much  water  will  be 
absorbed  by  the  leaves  of  trees,  and  carried  downwards  through  their 
alburnous  substance ;  though  it  is  certainly  through  this  substance  that 
the  sap  rises  under  other  circumstances.  If  a  branch  be  taken  from  a 
tree  when  its  leaves  are  mature,  and  one  leaf  be  kept  constantly  wet,  that 
leaf  will  absorb  moisture  and  supply  another  leaf  below  it  upon  the 
branch,  even  though  all  communication  between  them  through  the  bark 
be  intersected ;  and  if  a  similar  absorption  takes  place  in  the  straws 
of  wheat,  or  the  stems  of  other  plants,  and  a  retrograde  motion  of  the 
fluids  be  produced,  I  conceive  that  the  ascent  of  the  true  sap  or  organ- 


ON    THE    PREVENTION   OF    MILDEW    IX    PARTICULAR    CASES.  207 

isable  matter  into  the  seed-vessels  must  be  retarded,  and  that  it  may 
become  the  food  of  the  parasitical  plants,  which  then  only  may  grow 
luxuriant  and  injurious. 

This  view  of  the  subject,  whether  true  or  false,  led  me  to  the  following 
method  of  cultivating  the  pea  late  in  the  autumn,  by  which  my  table  has 
always  been  as  abundantly  supplied  during  the  months  of  September  and 
October  as  in  June  and  July ;  and  my  plants  have  been  very  nearly  as 
free  from  mildew.  The  ground  is  dug  in  the  usual  way,  and  the  spaces 
which  will  be  occupied  by  the  future  rows  are  well  soaked  with  water. 
The  mould  upon  each  side  is  then  collected,  so  as  to  form  ridges  seven  or 
eight  inches  above  the  previous  level  of  the  ground,  and  these  are  well 
watered  ;  after  which  the  seeds  are  sowed,  in  single  rows,  along  the  tops 
of  the  ridges.  The  plants  very  soon  appear  above  the  soil,  and  grow 
with  much  vigour,  owing  to  the  great  depth  of  the  soil,  and  abundant 
moisture.  Water  is  given  rather  profusely  once  in  every  week  or  nine 
days,  even  if  the  weather  proves  showery  ;  but  if  the  ground  be  thoroughly 
drenched  with  water  by  the  autumnal  rains,  no  further  trouble  is  neces- 
sary. Under  this  mode  of  management  the  plants  will  remain  perfectly 
green  and  luxuriant  till  their  blossoms  and  young  seed-vessels  are  des- 
troyed by  frost ;  and  their  produce  will  retain  its  proper  flavour,  which  is 
always  taken  away  by  mildew*. 

The  pea,  which  I  have  always  planted  for  autumnal  crops,  is  a  very 
large  kind,  of  which  the  seeds  are  much  shrivelled,  and  which  grows  very 
high :  it  is  now  very  common  in  the  shops  of  London,  and  my  name  has, 
I  believe,  been  generally  attached  to  it.  I  prefer  this  variety  because  it 
is  more  saccharine  than  any  other,  and  retains  its  flavour  better  late  in 
the  autumn;  but  it  is  probable  that  any  other  late  and  tall-growing 
variety  will  succeed  perfectly  well.  It  is  my  custom  to  sow  a  small 
quantity  every  ten  days  till  midsummer,  and  I  rarely  ever  fail  of  having 
my  table  well  supplied  till  the  end  of  October,  though  sometimes  a  severe 
frost  in  the  beginning  of  that  month  proves  fatal  to  my  later  crops. 

The  mildew  of  the  peach,  and  of  other  fruit-trees,  probably  originates 
in  the  same  causes  as  the  mildew  of  the  pea,  and  may  be  prevented  by 
similar  means.  When  the  roots,  which  penetrate  most  deeply  into  the 
soil,  and  are  consequently  best  adapted  to  supply  the  tree  with  moisture 
in  the  summer,  are  destroyed  by  a  noxious  subsoil,  or  by  excess  of  moisture 
during  the  winter,  I  have  observed  the  mildew  upon  many  varieties 

*  One  of  the  most  experienced  and  close  observers  of  our  Society  (Mr.  Dickson)  will  pro- 
bably recollect  having  seen  my  crops  of  peas  in  the  state  I  have  described,  late  in  the  autumn, 
in  my  garden  at  Elton. 


208  ON    THE    PREVENTION    OF    MILDEW    IN    PARTICULAR    CASES. 

of  the  peach  to  become  a  very  formidable  enemy.  Where,  on  the  con- 
trary, a  deep  and  fertile  dry  loam  permits  the  roots  to  extend  to  their 
proper  depth ;  and  where  the  situation  is  not  so  low  as  to  be  much 
infested  with  fogs,  I  have  found  little  of  this  disease :  and  in  a  forcing- 
house  I  have  found  it  equally  easy,  by  appropriate  management,  to  intro- 
duce or  prevent  the  appearance  of  it.  When  I  have  kept  the  mould 
very  dry,  and  the  air  in  the  house  damp  and  unchanged,  the  plants  have 
soon  become  mildewed ;  but  when  the  mould  has  been  regularly,  and 
rather  abundantly  watered,  not  a  vestige  of  the  disease  has  appeared. 

It  must  be  confessed  that  it  is  not  easy  to  account,  at  first  view,  for 
the  appearance  of  this  disease  under  some  of  the  preceding  and  various 
other  circumstances,  if  it  be  produced  by  a  parasitical  plant  which 
propagates  by  seeds  ;  but  all  we  ever  see  of  the  mildew  is  simply  its 
fructification  :  the  plant  itself,  if  it  be  one,  is  wholly  concealed  from  our 
senses ;  and  it  may  consequently  be  transferred  from  one  plant  to  another 
by  the  graft  or  bud,  and  never  become  visible  till  the  health  of  the  tree 
become  affected  by  other  causes.  I  could  state  some  cases  which  are 
very  favourable  to  this  opinion,  for  this  disease  appears  readily  to  be 
communicated  by  a  graft  to  another  tree,  when  that  grows  in  the  same 
soil,  and  in  similar  external  circumstances.  The  different  species  of 
minute  insects  which  feed  upon  the  bodies  of  our  domestic  cattle  are 
scarcely  ever  seen,  and  never  injurious  so  long  as  the  larger  animals 
retain  their  health  and  vigour ;  but  when  these  become  reduced  by 
famine  or  disease,  the  insects  multiply  with  enormous  rapidity,  and 
though  they  are  at  first  only  symptomatic  of  disease,  they  ultimately 
become  the  chief  and  primary  cause  of  its  continuance.  The  reciprocal 
operation  of  the  larger  plant  and  the  mildew  upon  each  other  may 
possibly  be  somewhat  similar. 

I  offer  the  preceding  opinions  merely  as  conjectures  :  the  hypothesis  I 
have  chosen  has  led  me  to  the  successful  treatment  of  the  disease  in 
particular  cases,  and  it  may  in  the  same  way  lead  others  :  and  I  therefore 
venture  to  submit  it  to  the  consideration  of  the  Horticultural  Society 
without  being  very  confident  of  its  truth.  If,  however,  the  countless 
millions  of  apparently  organised  bodies,  which  are  generated  by  the 
different  species  of  fungus,  be  not  seeds,  nature  appears  to  wander 
widely  from  its  ordinary  path  :  for  amidst  all  its  boundless  profusion 
and  exuberance,  it  does  not  ever,  in  other  cases,  appear  to  labour  wholly 
in  vain. 

P.S.  Observing  that  the  almond- trees,  round  the  metropolis,  are 
likely  to  produce  a  considerable  crop  in  the  present  year,  I  wish  to 


OX    THE    PREVENTION    OF    MILDEW    IN    PARTICULAR    CASES.  209 

recommend  stocks  of  this  species  for  Peaches  and  Nectarines  to  the 
attention  of  nurserymen,  as  likely  to  counteract  the  disposition  in 
some  varieties  of  the  peach  to  become  mildewed.  It  has  probably  other 
qualities  to  recommend  it,  for  it  is  obviously  much  more  nearly  allied  to 
the  peach  than  the  plum  is,  if  the  peach  and  nectarine  be  not,  as  I 
suspect  them  to  be,  varieties  only  of  the  common  almond  (Amygdalus 
communis).  The  almond  stocks  should  be  raised  and  retained  in  the 
nursery,  in  pots,  as  they  do  not  transplant  well. 


XXVIII.— ON  THE  CULTURE  OF  THE  SHALLOT,  AND  SOME  OTHER 
BULBOUS-ROOTED  PLANTS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  December  6th,  1813.] 

THE  habits  of  bulbous-rooted  plants  of  different  species,  relatively  to 
the  depths  to  which  they  naturally  retire  beneath  the  soil,  admit  of  much 
variation,  some  occupying  its  surface,  and  others  descending  considerably 
beneath  it.  These  circumstances  do  not  appear  to  have  been  sufficiently 
attended  to,  and  injurious  consequences  have  probably  been  the  result,  in 
many  cases. 

I  have  been  led  to  adopt  this  opinion,  and  to  make  the  experiments, 
which  are  the  subject  of  this  communication,  by  a  complaint  of  my 
gardener,  that  the  greater  part  of  his  crops  of  shallots  had,  during  several 
years,  generally  become  mouldy  and  perished  :  and  I  found,  on  enquiry, 
that  the  same  thing  had  very  often  occurred  in  other  gardens  of  the 
vicinity.  The  bulbs  had  in  all  cases  been  planted,  according  to  the 
directions  of  different  writers  upon  horticulture,  two  or  three  inches 
beneath  the  soil ;  and  to  this  cause  I  attributed  their  failure. 

A  few  bulbs  of  this  species,  which  were  divided,  as  far  as  practicable, 
into  single  buds,  were  therefore  planted  upon  the  surface  of  the  ground, 
or  rather  above  it,  some  very  rich  soil  having  been  placed  beneath  them, 
and  the  mould  having  been  raised  on  each  side  to  support  them,  till  they 
should  become  firmly  rooted.  This  mould  was  then  removed  by  the  hoe 
and  watering-pot,  and  the  bulbs  in  consequence  were  placed  wholly  out 
of  the  ground.  The  growth  of  these  plants  now  so  closely  resembled 
that  of  the  common  onion,  as  not  to  be  readily  distinguished  from  it ;  till 
the  irregularity  of  form,  resulting  from  the  numerous  germs  within 
each  bulb,  became  conspicuous.  The  forms  of  the  bulbs,  however, 
remained  permanently  different  from  all  I  had  ever  previously  seen  of 


210  CULTURE  OF  THE  SHALLOT, 

the  same  species,  being  much  more  broad,  and  less  long ;  and  the  crop 
was  so  much  better  in  quality,  as  well  as  much  more  abundant,  that  I 
can  confidently  recommend  the  mode  of  culture  adopted  to  the  attention 
of  every  gardener. 

A  few  experiments  similar  to  the  preceding  were  made  upon  bulbs  of 
the  oriental  hyacinth.  Some  of  these  were  planted  in  the  ordinary 
method  beneath  the  soil,  and  others  wholly  above  it,  the  mould  being 
raised  upon  each  side  to  cover  them,  and  subsequently  taken  away ;  and 
I  found  that  those  under  the  latter  mode  of  culture  flowered  most  strongly 
and  in  every  other  respect  succeeded  best.  A  compost,  of  great  richness, 
formed  of  matter  collected  just  without  the  gate  of  my  fold-yard,  and 
probably  consisting  of  nearly  equal  parts  of  earth  and  cow-dung,  by 
weight  (if  each  substance  had  been  perfectly  dry),  appeared  to  be  exceed- 
ingly well  adapted  to  this  plant ;  which  expends  much  in  a  very  short 
period  of  time  in  the  production  of  leaves  and  flowers,  and  retains  its 
foliage  only  a  short  time  afterwards,  and  therefore  probably  requires  more 
nutriment  than  it  can  generally  obtain  under  the  ordinary  modes  of 
culture.  It  is  true  that  this,  and  some  other  bulbous-rooted  plants,  pro- 
trude their  leaves  and  flowers  as  strongly,  when  supplied  with  water  only, 
as  when  growing  in  good  soil :  but  this  growth  is  chiefly  germination 
only,  and  during  this  process,  in  which  the  organs  of  the  plant  are  merely 
formed  out  of  matter  previously  assimilated,  it  may  be  questioned  whether 
a  single  particle  of  new  matter  be  ever  vitally  united  to  it. 

A  plant,  of  a  very  beautiful  variety  of  the  oriental  hyacinth,  which  had 
been  made  to  blossom  with  water  only  was,  at  my  request,  put  into  my 
hands  in  the  last  spring,  just  when  its  blossoms  had  begun  to  lose  their 
beauty.  Those  were  immediately  taken  off  but  the  stem  was  suffered  to 
remain,  and  the  plant  was  removed  from  the  bottom  of  water,  in  which 
it  grew,  into  a  pot  sufficiently  deep  to  receive  its  roots.  A  quantity  of 
the  rich  compost  above-mentioned  was  then,  in  successive  portions,  put 
into  the  pot,  and  washed  in  amongst  the  roots  ;  which  were  kept  properly 
separated  from  each  other.  The  bulb  itself  remained  wholly  out  of  the 
soil,  with  which  it  was  not  in  contact,  a  thin  layer  of  light  and  dry  sandy 
loam  intervening  between  it  and  the  rich  soil ;  and  the  bulb  was  also 
thinly  covered  with  the  same  material.  As  the  roots  of  the  plant  had 
been  accustomed  to  live  in  water,  the  compost  in  the  pot  was  at  first  kept 
very  wet ;  and  the  quantity  of  water  subsequently  given  was  lessened  very 
gradually  ;  and  as  its  leaves  had  been  little  exposed  to  light,  it  was  retained 
under  glass  till  the  leaves  perished.  The  bulb  was  then  examined,  and 
was  found  as  solid,  and  apparently  as  perfect,  as  it  would  have  been  if  it 


AND    OTHER    BULBOUS-ROOTED    PLANTS.  211 

had  germinated,  as  well  as  ultimately  only  grown,  in  a  rich  soil.  The 
water  in  this  case  occasioned  the  extension  of  the  roots,  and  the  develope- 
ment  of  the  leaves,  and  thus  was  instrumental  in  forming  organs  capable 
of  collecting  and  assimilating  new  matter  ;  but  exclusive  of  some  impu- 
rities it  contained,  it  probably  had  not  given  a  particle  of  organisable 
matter  to  the  plant.  The  formation  of  organs,  and  the  action  of  those 
organs  when  formed,  must  not  therefore  be  confounded,  as  has  generally 
been  done,  and  constantly  by  chemists  who  have  endeavoured  to  ascertain 
the  action  of  the  leaves  upon  the  surrounding  air  ;  and  hence  appear  to 
have  arisen  the  confused  and  contradictory  results  of  their  experiments. 

I  am  wholly  ignorant  of  the  mode  of  management  by  which  bulbous 
roots  of  different  kinds,  acquire  so  much  greater  perfection  in  the  hands 
of  the  Dutch  gardeners,  than  in  those  of  our  own  countrymen  :  but  I 
suspect  that  the  Dutch  gardeners  employ  subsoils  of  very  great  depth  and 
richness,  with  which  the  bulbs  are  prevented  coming  into  contact  by  the 
intervention  of  a  thin  layer  of  dry  sand,  with  which  substance  they  may 
be  also  thinly,  or  only  partially,  covered ;  and  I  am  in  part  led  to  adopt 
this  opinion,  by  observing  the  similarity  of  character  in  the  external 
membranes  of  their  bulbous  roots,  and  of  those  of  the  shallots,  which  had 
been  wholly  exposed  to  the  sun  and  air. 


XXIX.— ON   THE    APPLICATION    OF    MANURE    IN    A    LIQUID    FORM    TO 

PLANTS    IN    POTS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  11th,  1814.] 

THE  quantity  of  earth,  which  the  most  firm  and  solid  parts  of  trees 
afford  by  analysis,  is  well  known  to  be  very  small ;  and  even  the  species 
of  these  earths  have  been  proved,  by  the  younger  Saussure,  to  be 
dependent,  to  a  great  extent,  upon  the  component  parts  of  the  soil,  in 
which  the  trees  happen  to  have  grown.  A  large  extent  and  depth  of 
soil  seem  therefore  to  be  no  further  requisite  to  trees  than  to  afford  them 
a  regular  supply  of  water,  and  a  sufficient  quantity  of  organisable  matter ; 
and  the  rapid  growth  of  plants  of  every  kind,  when  their  roots  are  con- 
fined in  a  pot  to  a  small  quantity  of  mould,  till  that  becomes  exhausted, 
proves  sufficiently  the  truth  of  this  position. 

I  have  shown  in  a  former  communication*,  that  a  seedling  plum-stock, 
growing  in  a  small  pot,  attained  the  height  of  nine  feet  seven  inches,  in  a 

*  See  page  194. 


212  ON    THE    APPLICATION    OF    MANURE    IN    A    LIQUID    FORM. 

single  season ;  which  is,  I  believe,  a  much  greater  height  than  any 
seedling  tree  of  that  species  was  ever  seen  to  attain  in  the  open  soil.  But 
the  quantity  of  earth,  which  a  small  pot  contains,  soon  becomes  exhausted, 
relatively  to  one  kind  of  plant ;  though  it  may  be  still  fertile  relatively  to 
others  :  and  the  size  of  the  pot  cannot  be  changed  sufficiently  often  to 
remedy  this  loss  of  fertility ;  and  if  it  were  ever  so  frequently  changed, 
the  mass  of  mould,  which  each  successive  emission  of  roots  would  enclose, 
must  remain  the  same. 

Manure  can  therefore  probably  be  most  beneficially  given  in  a  purely 
liquid  state ;  and  the  quantity  which  trees  growing  in  pots  have  thus 
taken,  under  my  care,  without  any  injury  and  with  the  greatest  good 
Affect,  has  so  much  exceeded  every  expectation  I  had  formed,  that  I  am 
induced  to  communicate  to  the  Society  the  particulars  and  the  result  of 
my  experience. 

I  have  for  some  years  appropriated  a  forcing-house,  at  Dovvnton,  to 
the  purposes  of  experiment  solely  upon  fruit-trees  ;  which,  as  I  have 
frequent  occasion  to  change  the  subjects  upon  which  I  have  to  operate, 
are  confined  in  pots.  These  were  at  first  supplied  with  water  in  which 
about  one-tenth,  by  measure,  of  the  dung  of  pigeons,  or  domestic  poultry, 
had  been  infused ;  and  the  quantity  of  these  substances  (generally  the 
latter)  was  increased  from  one-tenth  to  a  fourth.  The  water,  after 
standing  forty-eight  hours,  acquired  a  colour  considerably  deeper  than 
that  of  porter  ;  and  in  this  state  was  drawn  off  clear,  and  employed  to 
feed  trees  of  the  vine,  the  mulberry,  the  peach,  and  other  plants.  A 
second  quantity  of  water  was  then  applied,  and  afterwards  used  in  the 
same  manner;  when  the  manure  was  changed,  and  the  same  process 
repeated. 

The  vine  and  mulberry  tree,  being  very  gross  feeders,  were  not  likely 
to  be  soon  injured  by  this  treatment ;  but  I  expected  the  peach-tree, 
which  is  often  greatly  injured  by  excess  of  manure  in  a  solid  state,  to 
give  early  indications  of  being  over- fed.  Contrary,  however,  to  my 
expectations  the  peach-tree  maintained,  at  the  end  of  two  years,  the  most 
healthy  and  luxuriant  appearance  imaginable,  and  produced  fruit  in  the 
last  season  in  greater  perfection  than  I  had  ever  previously  been  able  to 
obtain  it.  Some  seedling  plants  had  then  acquired,  at  eighteen  months 
old,  (though  the  whole  of  their  roots  had  been  confined  to  half  a  square 
foot  of  mould,)  more  than  eleven  feet  in  height  with  numerous  branches, 
and  have  afforded  a  most  abundant  and  vigorous  blossom  in  the  present 
spring,  which  has  set  remarkably  well ;  and  those  trees  which  had  been 
most  abundantly  supplied  with  manure  have  displayed  the  greatest  degrees 
of  health  and  luxuriance. 


ON    THE    APPLICATION    OF    MANURE    IN    A    LIQUID    FORM.  213 

A  single  orange- tree  was  subjected  to  the  same  mode  of  treatment, 
and  grew  with  equal  comparative  vigour,  and  appeared  to  be  as  much 
benefited  by  abundant  food  as  even  the  vine  and  mulberry  tree. 

An  opinion  generally,  though  I  think  somewhat  erroneously,  prevails 
that  many  plants,  particularly  the  different  species  and  varieties  of  heath, 
require  a  very  poor  soil  in  pots;  but  these  might,  I  conceive,  with 
propriety,  be  said  to  require  a  peculiar  soil ;  for  I  have  never  seen  the 
common  species  of  this  genus  spring  with  so  much  luxuriance  as  from  a 
deep  bed  of  vegetable  mould,  which  had  been  recently  very  thickly  covered 
with  the  ashes  of  a  preceding  crop  of  heaths  and  other  plants  that  had 
been  burned  upon  it.  And  I  believe,  if  the  branches  and  leaves  of  the 
common  species  of  heath  were  placed  to  decompose  in  water,  and  such 
water  were  afterwards  given  to  the  tender  exotic  species,  that  these, 
how  heavily  soever  the  water  might  be  loaded  with  organisable  matter,, 
would  be  found  as  little  capable  of  being  injured  by  abundant  food  as  the 
vine  or  mulberry  tree,  though  the  species  of  food  which  would  best  suit 
those  plants  might  prove  to  every  species  of  heath  destructive  and 
poisonous. 


XXX.— ON   THE    ILL   EFFECTS  OF  EXCESSIVE  HEAT  IN   FORCING-HOUSES 
DURING   THE    NIGHT. 

[Read  before  the  HORTICULTURAL  SOCIETY,  June  17 th,  1814.] 

FEW  gardeners,  if  any,  have  ever  believed  plants  to  be  at  all  endued 
with  powers  of  sensation  and  perception  similar  to  those  of  animals ;  or 
to  be,  in  any  degree,  susceptible  of  pleasure  or  pain ;  and  yet  it  is  very 
questionable  whether  there  has  ever  been  a  single  gardener,  who,  in  the 
management  of  fruit-trees  in  a  forcing-house,  did  not  in  some  respects 
err  by  treating  his  trees  as  he  would  have  done,  if  he  had  supposed  them 
to  possess  such  powers.  Being  fully  sensible  of  the  comforts  of  a  warm 
bed  in  a  cold  night,  and  of  fresh  air  in  a  hot  day,  the  gardener  generally 
treats  his  plants  as  he  would  wish  to  be  treated  himself;  and,  conse- 
quently, though  the  aggregate  temperature  of  his  house  be  nearly  what  it 
ought  to  be,  its  temperature  during  the  night,  relatively  to  that  of  the  day, 
is  almost  always  much  too  high.  The  consequences  of  this  excess  of  heat 
during  the  night  are,  I  have  reason  to  believe,  in  all  cases  highly  injurious 
to  the  fruit-trees  of  temperate  climates,  and  not  at  all  beneficial  to  those 
of  tropical  climates  ;  for  the  temperature  of  these  is,  in  many  instances, 


214  ON    THE    HEAT    IN    FORCING-HOUSES. 

low  during  the  night.  In  Jamaica,  and  other  mountainous  islands  of 
the  West  Indies,  the  air  upon  the  mountains  becomes,  soon  after  sunset, 
chilled  and  condensed,  and,  in  consequence  of  its  superior  gravity, 
descends  and  displaces  the  warm  air  of  the  valleys ;  yet  the  sugar-canes 
are  so  far  from  being  injured  by  this  sudden  decrease  of  temperature, 
that  the  sugars  of  Jamaica  take  a  higher  price  in  the  market  than  those 
of  the  less  elevated  islands,  of  which  the  temperature  of  the  day  and 
night  is  subject  to  much  less  variation. 

During  the  progress  of  germination,  in  the  spring,  great  chemical 
changes  take  place  in  the  component  parts  of  the  sap  of  trees,  analogous 
to  those  which  have  been  observed  in  the  germination  of  seeds.  I  could 
not  detect  any  vestige  of  saccharine  matter  %in  the  alburnum,  either  of 
the  stem  or  roots  of  the  sycamore  tree  in  the  winter ;  but  in  the  spring, 
its  sap  became  very  sensibly  sweet :  and  I  found  this  sap  to  be  much 
more  saccharine,  and  of  greater  specific  gravity,  in  large  trees,  which 
were  prepared  to  nourish  an  abundant  blossom,  than  in  small  and  young 
trees.  The  sap  of  the  same  tree  proved  also  to  be  subject  to  some 
variations  of  specific  gravity,  at  the  same  period  of  the  spring,  in  different 
years ;  and  Duhamel  has  observed,  that  the  sap  of  the  sugar  maple 
becomes  first  saccharine,  and  afterwards  acquires  an  herbaceous  taste ; 
in  the  latter  state,  it  probably  is  best  calculated  to  feed  the  blossoms  and 
unfolded  buds. 

At  the  period  of  the  preceding  chemical  changes  in  the  qualities  and 
properties  of  the  sap,  previous  to  the  growth  of  the  leaves,  that  fluid  is 
found  to  ascend  during  the  warm  part  of  the  day,  and  to  flow,  in  many 
species  of  trees,  from  any  recent  wound,  and  to  fall  again  during  the 
night,  particularly  if  that  be  cold ;  and  as  variations  of  temperature  are 
the  apparent  cause  of  these  motions,  it  appears  not  improbable,  that  the 
chemical  changes,  which  take  place  in  it  at  this  period,  are  promoted  by 
the  same  agents. 

Some  experiments  which  I  have  made  upon  germinating  seeds,  have 
perfectly  satisfied  me,  that  these  afford  plants  of  greater  or  less  vigour  in 
proportion  as  external  circumstances  are  favourable  in  promoting  beneath 
the  soil  the  necessary  changes  in  the  nutritive  matter  they  contain  ;  and 
I  suspect  that  a  large  portion  of  the  blossoms  of  the  cherry  and  other 
fruit-trees  in  the  forcing-house  often  proves  abortive,  because  they  are 
forced,  by  too  high  and  uniform  a  temperature,  to  expand  before  the  sap 
of  the  tree  is  properly  prepared  to  nourish  them. 

I  have  therefore  been  led,  during  the  last  three  years,  to  try  the  effects 
of  keeping  up  a  much  higher  temperature  in  the  day  than  in  the  night ; 


ON    THE    HEAT    IN    FORCING-HOUSES.  215 

and  as  experiments  of  this  kind  cannot  bo  made  by  the  common  gardener, 
who  must  not  risk  the  sacrifice  of  his  employer's  crops  of  fruit,  I  trust 
the  following  account  will  be  honoured  by  the  approbation  of  the  Horti- 
cultural Society,  though  the  experiments  have  been  chiefly  confined  to 
the  peach-tree. 

As  early  in  the  spring  as  I  wished  the  blossoms  of  my  peach-trees  to 
unfold,  my  house  was  made  warm  during  the  middle  of  the  day ;  but 
towards  night  it  was  suffered  to  cool,  and  the  trees  were  then  sprinkled, 
by  means  of  a  large  syringe,  with  clear  water,  as  nearly  at  the  tempera- 
ture at  which  that  usually  rises  from  the  ground,  as  I  could  obtain  it ; 
and  little  or  no  artificial  heat  was  given  during  the  night,  unless  there 
appeared  a  prospect  of  frost.  Under  this  mode  of  treatment  the  blos- 
soms advanced  with  very  great  vigour,  and  as  rapidly  as  I  wished  them, 
and  presented,  when  expanded,  a  larger  size  than  1  had  ever  before  seen 
of  the  same  varieties  :  which  circumstance  is  not  unimportant,  because 
the  size  of  the  blossom,  in  any  given  variety,  regulates,  to  a  very  consider- 
able extent,  the  bulk  of  the  future  fruit.  As  soon  as  the  blossoms  were 
expanded,  and  the  pollen  began  to  shed,  water  was  applied  in  less 
quantity,  as  a  light  shower,  sufficient  to  wet  the  pollen,  without  washing 
it  off;  but  when  the  pollen  was  chiefly  shed,  I  again,  to  promote  its 
absorption,  sprinkled  the  trees  abundantly  with  water,  having  previously 
often  observed  that  heavy  showers  of  rain  are  at  this  period  always 
highly  beneficial  to  the  blossoms  of  the  apple  trees  in  our  orchards ;  and 
almost  every  blossom  of  my  peach-trees  set  most  perfectly.  The  watering 
was  regularly  continued  till  the  fruit  became  very  nearly  ripe,  the  roots 
of  the  trees  being,  at  the  same  time,  abundantly  supplied  with  moisture 
and  food  in  the  manner  detailed  in  my  last  paper,  in  which  I  have  stated 
the  more  than  ordinary  size  and  perfection  of  the  fruit. 

My  house  had  been  previously  much  infested  with  the  red  spider*;  but 
not  a  single  one  now  appeared,  nor  scarcely  an  aphis ;  and  the  young 
wood  became  remarkable  for  the  shortness  of  its  joints,  and  the  thickness, 
comparatively  with  the  length  of  its  shoots.  A  gardener,  who  is  preju- 
diced in  favour  of  old  customs,  will  possibly  imagine  that  he  supplies  the 
place  of  the  cool  evening  dews  of  nature,  and  of  the  water  in  the  pre- 
ceding experiment,  by  sprinkling  his  flues  with  water,  and  filling  his 
house  abundantly  with  steam.  But  the  effect  of  no  two  operations  can 
be  more  different :  in  the  one,  the  plant  is  suddenly  chilled  by  cold  water, 

*  I  suspect,  but  I  am  no  entomologist,  that  two  distinct  species  of  insect  are  confounded 
under  this  name,  one  of  which  forms  a  web,  which  the  other  does  not.  The  latter  kind  often 
abounds  in  the  open  air,  upon  pear-trees,  and  appears  to  be,  in  the  forcing-house,  a  much 
hardier  insect  thrtn  the  other. 


216  ON    THE    HEAT    IN    FORCING-HOUSES. 

and  subsequently  kept  cool  by  the  evaporation  of  the  water  during  the 
night :  in  the  other,  the  steam  is  precipitated  upon  the  leaves  and 
branches  of  the  trees,  to  which  it  necessarily  communicates  much  heat. 
The  former  operation  nearly  resembles  that  of  the  shower-bath,  some- 
times used  in  this  country,  in  which  the  patient  is  suddenly  chilled  by  a 
heavy  shower  of  cold  water ;  the  other  resembles  the  hot  steam-bath  of 
Russia,  in  which  he  is  violently  heated  ;  and  if  the  gardener  were  to  try 
each  of  these  processes  upon  himself,  during  a  single  night,  I  suspect  he 
would  arise  in  the  following  morning  with  very  different  feelings,  unless 
he  were  blest  with  much  peculiar  hardness  of  constitution.  It  is  true, 
that  plants  do  not  appear  to  possess  sensation  in  the  ordinary  sense  of 
that  term,  as  it  is  applied  to  animals ;  but  nature,  in  forming  its  whole 
organic  creation,  seems  to  have  proceeded  so  much  by  substitutions  and 
additions,  that  simple  sensation,  in  its  strict  and  limited  sense,  abstracted 
from  all  powers  of  perception,  may  not  improbably  be  as  widely  diffused 
as  organisation  itself;  and  animal  and  vegetable  life  may  be,  in  conse- 
quence, susceptible  of  similar  injuries  from  similar  external  causes.  The 
influence  of  hot  and  damp  air  upon  both,  is  greatly  more  powerful 
than  that  of  dry  air  of  the  same  temperature.  In  the  experiments  of 
which  Sir  Charles  Blagden  has  given  an  account  in  the  Philosophical 
Transactions  of  1775,  he,  with  Sir  Joseph  Banks  and  others,  sustained 
without  injury  a  temperature  of  260  degrees  in  dry  air  ;  but  they  found 
damp  air,  at  half  that  temperature,  to  be  scarcely  supportable  :  and 
every  gardener  knows,  how  quickly  the  leaves  of  his  plants  are  injured 
by  the  combined  action  of  heat  and  moisture. 

The  succulent  shoots  of  trees,  however,  always  appear  to  grow  most 
rapidly,  in  a  damp  heat,  during  the  night ;  but  it  is  rather  elongation 
than  growth  which  then  takes  place.  The  spaces  between  the  bases  of 
the  leaves  become  longer,  but  no  new  organs  are  added ;  and  the  tree, 
under  such  circumstances,  may  with  much  more  reason  be  said  to  be 
drawn,  than  to  grow ;  for  the  same  quantity  only  of  material  is  extended 
to  a  greater  length,  as  in  the  elongation  of  a  wire. 

Another  ill  effect  of  high  temperature  during  the  night  is,  that  it 
exhausts  the  excitability  of  the  tree  much  more  rapidly  than  it  promotes 
the  growth,  or  accelerates  the  maturity  of  the  fruit :  which  is  in  conse- 
quence ill  supplied  with  nutriment,  at  the  period  of  its  ripening,  when 
most  nutriment  is  probably  wanted.  The  muscat  of  Alexandria,  and 
other  late  grapes,  are,  owing  to  this  cause,  often  seen  to  wither  upon 
the  branch  in  a  very  imperfect  state  of  maturity  ;  and  the  want  of 
richness  and  flavour  in  other  forced  fruits  is,  1  am  very  confident,  often 


ON    THE    HEAT    IN    FORCING-HOUSES,  217 

attributable  to  the  same  cause.  There  are  few  peach -houses,  or  indeed 
forcing-houses  of  any  kind,  in  this  country,  in  which  the  temperature  does 
not  exceed,  during  the  night,  in  the  months  of  April  and  May,  very 
greatly  that  of  the  warmest  valley  in  Jamaica  in  the  hottest  period  of  the 
year :  and  there  are  probably  as  few  forcing-houses  in  which  the  trees 
are  not  more  strongly  stimulated  by  the  close  and  damp  air  of  the  night, 
than  by  the  temperature  of  the  dry  air  of  the  noon  of  the  following  day. 
The  practice  which  occasions  this  cannot  be  right :  it  is  in  direct  oppo- 
sition to  nature  :  and  I  need  not  point  out  to  the  intelligent  members  of 
the  Horticultural  Society,  that  the  more  nearly  nature,  in  its  best 
climates  and  most  favourable  seasons,  is  copied  as  to  temperature,  the 
more  perfect  will  be  the  productions  of  the  gardener's  art. 


XXXI.— ON  THE  MODE  OF  PROPAGATION  OF  THE  LYCOPERDON 
CANCELLATUM*.  A  SPECIES  OF  FUNGUS,  WHICH  DESTROYS  THE 
LEAVES  AND  BRANCHES  OF  THE  PEAR-TREE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  December  5th,  1815.] 

I  HAD  the  honour,  two  years  ago,  to  address  to  the  Horticultural 
Society  some  observations  upon  the  propagation  of  these  supposed  species 
of  parasitical  plants,  which,  under  the  name  of  fungi-f*,  appear  as  diseases 
upon  other  living  plants :  and  of  other  supposed  species  of  the  same  tribe, 
which  decompose  and  feed  upon  organic  substances,  that  have  ceased  to 
live.  In  the  present  communication,  I  shall  endeavour  to  show,  that  one 
of  these,  at  least,  is  a  parasitical  plant,  which  propagates  like  other  plants, 
by  seeds. 

I  observed,  about  seven  years  ago,  a  disease  upon  a  few  of  the  leaves 
of  one  of  the  pear-trees  in  my  garden  at  Downton.  Bright  yellow  spots, 
from  which  a  small  quantity  of  liquid  exuded,  appeared  upon  the  upper 
surfaces  of  the  leaves  in  June;  and  subsequently,  several  conic  processes, 
about  one  third  of  an  inch  in  length,  were  protruded  from  the  same 
parts,  but  from  the  opposite  surface,  of  each  leaf;  and  from  these  a 
large  quantity  of  brown  impalpable  powder,  consisting  of  very  minute 
globular  bodies,  was  discharged  in  August  and  September.  These  minute 

*  I  am  indebted  for  the  name  of  this  species  of  fungus  to  the  extensive  information  of  Mr. 
Dickson,  who  referred  me  to  the  Flora  Danica  for  a  delineation  of  it :  but  Sir  Joseph  Banks 
subsequently  showed  me  a  drawing  of  it  by  Mr.  Bauer,  which  is  much  more  elaborate  and 
correct. 

t  See  page  204. 


218  ON  THE  LYCOPERDON  CANCELLATUM. 

globular  bodies  I  concluded  to  be  seeds  of  a  species  of  fungus  ;  but  as  a 
few  only  of  the  leaves  of  my  trees  were  affected,  and  no  very  injurious 
effects  were  visible,  I  did  not  take  any  measures  to  prevent  their  disper- 
sion over  my  garden. 

I  did  not,  however,  long  remain  ignorant  of  the  formidable  nature 
of  my  new  enemy ;  for  within  two  years,  every  pear-tree  in  my  garden 
became  in  some  degree  diseased.  The  leaves  only,  at  first,  appeared  to 
be  injured  ;  but  the  disease  soon  extended  itself  to  the  annual  branches, 
in  many  protuberant  yellow  spots,  beneath  which  the  bark  was  found  to 
have  acquired  a  bright  yellow  colour :  and  as  far  as  this  colour  extended, 
the  bark,  and  the  wood  beneath  it  invariably  perished,  either  in  the  same 
or  following  season,  leaving  wounds  similar  to  these  inflicted  by  canker, 
but  less  curable.  The  fruit  also  became  diseased  and  worthless,  and  almost 
all  the  young  shoots,  when  once  attacked,  perished  in  the  following 
winter.  These  effects  were  not  confined  to  my  garden,  but  extended 
to  the  pear-trees  in  an  orchard  which  was  two  hundred  yards  distant ; 
and  I  Ccinnot  entertain  a  doubt,  but  that  the  disease  was  communicated 
to  these  by  seeds  which  had  been  conveyed  by  the  prevalent  west  winds. 
I  endeavoured,  during  the  summers  of  1813  and  1814,  to  check  its 
progress  in  my  garden,  by  picking  off  every  diseased  leaf ;  but  I  found 
all  my  efforts  nearly  abortive,  and  1  have  been  obliged  to  destroy  the 
greater  part  of  my  pear-trees :  those  which  remain  have  become  annu- 
ally more  diseased,  and  I  fear  never  can  be  ultimately  preserved,  unless 
a  remedy  for  the  disease  can  be  discovered. 

I  tried  the  effect,  in  the  last  season,  of  sprinkling  the  leaves  of 
different  pear-trees,  just  at  the  period  when  eht  liquid  exuded  from 
the  spots  upon  their  surfaces,  with  quick-lime  and  fresh  wrood 
ashes,  in  which  the  alkali  and  lime  were  in  a  caustic  state ;  and  with 
flowers  of  sulphur.  The  spots  to  which  the  quick-lime  and  ashes  were 
applied,  soon  became  paler ;  but  I  had  not  an  opportunity  of  observing 
the  ultimate  effect  of  these  substances :  for  almost  all  the  leaves  of  the 
pear-trees  upon  my  walls,  in  the  last  season,  became  covered  with  black 
and  lifeless  spots,  and  fell  off  prematurely.  Those  of  a  single  small 
standard  pear-tree,  on  which  flowers  of  sulphur  had  been  sprinkled, 
remained  alive  till  late  in  the  autumn ;  and  upon  these  I  did  not  observe 
the  sulphur  to  operate  in  any  degree,  till  the  period  at  which  the  conic 
processes  above-mentioned  would  have  appeared ;  but  the  yellow  spots 
then  became  black,  and  perished,  without  affording  seeds ;  whence  I 
have  reason  to  hope,  that  flowers  of  sulphur  will  prevent,  in  some 
measure  at  least,  the  rapid  extension  of  this  disease. 


ON  THE  LYCOPERDON  CANCELLATUM.  219 

As  the  existence  of  this  species  of  fungus  appeared,  three  years  ago, 
to  be  confined  to  my  garden  and  a  few  pear-trees  in  its  vicinity,  and 
to  the  hawthorn  in  an  adjoining  hedge  (for  it  attacks  the  hawthorn  as 
well  as  the  pear-tree),  I  then  thought  that  it  would  be  practicable  to 
ascertain  decisively  the  means  by  which  it  transfers  itself  from  one  tree 
to  another  :  and  this  appeared  to  me  to  be  an  important  object;  because 
the  habits  of  the  lycoperdon  cancellatum,  and  of  the  fungus  which 
forms  the  rust  or  mildew  of  wheat,  are,  in  many  respects,  very  similar. 

I  had  so  often  tried,  without  success,  to  transfer  the  mildew  of  wheat, 
and  other  plants,  from  a  diseased  to  a  healthy  subject,  in  the  same 
season,  that  I  had  not  any  expectation  of  succeeding  in  an  attempt  of 
that  kind ;  but  I  thought  it  not  improbable,  that  I  might  succeed  in 
communicating  this  disease  to  seedling  plants  of  the  pear-tree,  having 
long  ago  satisfied  myself  that  the  species  of  fungus,  which  forms  the 
mildew  of  wheat,  always  rises  from  the  root  of  the  plant. 

I  have  many  years  been  in  the  habit  of  raising  annually  pear-trees 
from  seeds,  with  the  hope  and  expectation  of  obtaining  new  and  hardy 
varieties  for  the  dessert  in  winter  ;  which  may  succeed  without  the  pro- 
tection of  a  wall ;  and  as  the  means  I  employ  to  obtain  seeds  well 
calculated  for  my  purpose,  necessarily  cost  me  a  good  deal  of  time  and 
labour,  I  have  always  planted  them  in  pots,  and  in  the  kind  of  mould 
which  long  experience  has  pointed  out  to  me  as  the  best.  This  I  have 
always  obtained,  at  the  period  of  sowing  the  seeds,  in  January  or 
February,  from  the  banks  of  a  river  at  some  distance  from  my  garden ; 
and  in  this  mould  my  seedling  pear-trees  always  sprang  up,  and  remained 
during  the  first  season  perfectly  free  from  disease.  In  the  spring  of 
1813,  a  portion  of  this  mould,  which  I  did  not  want,  was  intentionally 
placed  very  near  some  hawthorns  and  pear-trees,  upon  which  the  lyco- 
perdon cancellatum  abounded,  where  it  remained  till  the  spring  of  1814, 
when  it  was  put  into  pots,  and  new  seeds  deposited  in  it.  These  sprang 
up  as  usual,  and  remained  in  perfect  health  till  the  end  of  May  or  begin- 
ning of  June ;  when  the  fungus  presented  itself  upon  almost  all  the  first 
true  leaves  of  the  plants,  which  leaves  had  composed  the  plumules  of  the 
seeds. 

That  the  fungus,  in  this  case,  rose  from  the  ground,  will,  I  think, 
scarcely  be  questioned ;  but  it  is  necessary  to  state,  that  the  seeds  were 
all  taken  from  trees  which  were  not  quite  free  from  disease  ;  and  that  I 
saw  in  the  last  spring  some  diseased  plants,  in  a  case  where  every  pre- 
caution, except  that  of  using  new  pots  (which  had  been  my  previous 
custom),  had  been  taken ;  and  therefore,  whilst  so  little  is  known  respect- 
ing the  habits  of  plants  of  this  tribe,  the  preceding  facts  are  not  sufficient 


220  ON  THE  LYCOPERDON  CANCELLATUM. 

to  support  a  decision,  that  the  source  of  the  disease  might  not  have  been 
in  the  seeds  themselves.  For  as  the  fructification  is  probably  everything 
which  is  seen  of  this,  and  many  other  parasitical  fungous  plants,  the 
plant  may  extend  in  minute  filaments  through  the  whole  body  of  the  tree 
which  supports  it ;  and  it  appears  in  this  view  of  the  subject  possible, 
that  these  slender  filaments  may  extend  into  the  seeds.  The  following 
circumstances,  however,  militate  strongly  in  opposition  to  this  conclusion. 
A  great  number  of  seedling  pear-trees,  which  were  very  much  diseased, 
were  removed,  in  the  last  spring,  from  my  garden  to  a  distant  situation, 
after  having  had  their  roots  and  stems  carefully  and  repeatedly  washed, 
and  brushed,  so  as  to  remove  from  them  every  particle  of  the  mould  in 
which  they  had  previously  grown  ;  and  upon  these  not  a  vestige  of 
disease  has  since  appeared.  Grafts  also,  which  were  formed  of  parts  of 
diseased  trees,  have  in  all  cases  produced  perfectly  healthy  foliage,  even 
when  inserted  into  the  branches  of  other  diseased  trees  ;  which  circum- 
stance I  think  interesting,  because  it  tends  to  point  out  a  further 
apparent  similarity  in  the  habits  of  this  species  of  fungus,  and  that  which 
forms  the  mildew  of  wheat :  which  ceases  to  vegetate  as  soon  as  the 
straw  is  severed  from  its  roots,  though  that  remains  for  some  time  green 
and  living  :  whence  arises  the  advantage  of  cutting  mildewed  crops  of 
wheat  in  an  immature  state.  Further  experience  can,  however,  alone 
decide  these  points  :  and  the  only  inference  I  wish  to  draw  from  the  facts 
I  have  stated  is,  that  the  lycoperdon  cancellatum  is  capable,  under 
certain  circumstances,  of  being  transferred  from  one  plant  to  another  in 
its  vicinity,  by  means  of  its  seeds. 

I  observed  this  disease,  in  the  last  summer,  upon  a  few  of  the  leaves 
of  several  pear-trees  in  the  vicinity  of  London ;  and  I  fear  that  the 
fungus  which  occasions  it  is  an  imported  species,  that  is  likely  to  increase 
in  our  climate,  and  to  become,  in  some  situations  at  least,  extremely 
injurious  to  one  of  the  most  valuable  of  our  fruit-trees.  I  have  met  with 
several  intelligent  gardeners  who,  at  first  view,  thought  they  had  observed 
this  disease  some  years  ago ;  but  on  further  inspecting  its  habits  and 
injurious  effects,  they  have  always  changed  their  opinion. 

The  enormous  injury  which  the  crops  of  wheat  sustained  in  the  year 
1814  and  other  seasons,  by  mildew,  attaches  a  great  degree  of  interest 
to  the  investigation  of  the  habits  of  parasitical  plants  of  this  tribe  ;  and 
the  similarity  of  habits  of  the  mildew  of  wheat,  and  of  the  lycoperdon 
cancellatum,  renders  it  probable  that  both  are  propagated  in  the  same 
manner.  I  therefore  venture  to  hope  that  the  foregoing  account,  though 
very  imperfect,  of  the  apparent  mode  of  propagation  of  the  latter  plant, 
may  be  thought  deserving  the  attention  of  the  Horticultural  Society. 


221 


XXXII.— ON   THE    EFFECTS    OF    DIFFERENT    KINDS    OF   STOCKS    IN 

GRAFTING. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  6th,  1816.] 

THE  practice  of  propagating  fruits  of  different  species,  by  grafting  upon 
stocks  of  other  species,  has  been  so  extensive,  both  in  ancient  and  modern 
times,  that  the  good  and  ill  effects  of  it  can  scarcely  be  supposed  to  have 
escaped  the  observation  of  gardeners.  Accurate  information  upon  this 
subject  can,  however,  only  be  acquired  by  experiments  accurately  made, 
and  closely  attended  to,  during  many  successive  years,  upon  the  com- 
parative good  and  ill  effects  of  stocks  of  different  species,  when  growing 
in  soils  of  the  same,  and  of  different  qualities :  and  no  such  experiments, 
have,  I  believe,  ever  been  made  in  this  country,  nor,  to  a  proper  extent, 
in  any  other.  Duhamel  has  pointed  out,  with  his  usual  ability,  the 
erroneous  opinions  entertained  by  his  countrymen  upon  this  subject,  and 
has  given  some  valuable  information ;  but  he  admits,  that  relatively  to 
some  very  important  points,  he  only  details  the  opinions  of  others ;  and 
he  laments  that  he  has  not  himself  made  the  experiments  necessary  to 
decide  the  questions,  which  he  wishes  to  investigate.  I  also  feel,  that  I 
am  not,  by  any  means,  master  of  the  subject  upon  which  I  have  taken 
up  my  pen  to  write  :  but  I  believe  that  I  have  made  and  seen  the 
result  of  more  experiments,  during  the  last  thirty-five  years,  than  any 
other  person ;  and  I  venture  to  hope,  that  my  experience  enables  me 
to  draw  a  few  conclusions,  which  may  prove  useful. 

Whenever  the  stock,  and  graft,  or  bud,  are  not  perfectly  well  suited  to 
each  other,  an  enlargement  is  well  known  always  to  take  place  at  the 
point  of  their  junction,  and  generally  to  some  extent,  both  above  and 
below  it.  This  is  particularly  observable  in  peach-trees,  which  have 
been  grafted,  at  any  considerable  height  from  the  ground,  upon  plum 
stocks ;  and  it  appears  to  arise  from  obstruction,  which  the  descending 
sap  of  the  peach-tree  meets  with  in  the  bark  of  the  plum  stock  ;  for  the 
effects  produced,  both  upon  the  growth  and  produce  of  the  tree,  are 
similar  to  those  which  occur  when  the  descent  of  the  sap  is  impeded  by  a 
ligature,  or  by  the  destruction  of  a  circle  of  bark,  in  the  manner  recom- 
mended by  Mr.  Williams  in  a  former  volume  of  the  Horticultural 
Transactions  *.  The  disposition  in  young  trees  to  produce  and  nourish 
blossom,  buds,  and  fruit,  is  increased  by  this  apparent  obstruction  of  the 

*  Vol.  I.  page  108. 


222  THE    EFFECTS    OF    DIFFERENT    KINDS    OF    STOCKS    IN    GRAFTING. 

descending  sap ;  and  the  fruit  of  such  young  trees  ripens,  I  think,  some- 
what earlier  than  upon  other  young  trees  of  the  same  age,  which  grow 
upon  stocks  of  their  own  species ;  but  the  growth  and  vigour  of  the  tree, 
and  its  power  to  nourish  a  succession  of  heavy  crops,  are  diminished, 
apparently,  by  the  stagnation,  in  the  branches  and  stock,  of  a  portion  of 
that  sap,  which,  in  a  tree  growing  upon  its  own  stem,  or  upon  a  stock  of 
its  own  species,  would  descend  to  nourish  and  promote  the  extension  of 
the  roots.  The  practice,  therefore,  of  grafting  the  pear-tree  on  the 
quince  stock,  and  the  peach  and  apricot  on  the  plum,  where  extensive 
growth  and  durability  are  wanted,  is  wrong  ;  but  it  is  eligible  wherever 
it  is  wished  to  diminish  the  vigour  and  growth  of  the  tree,  and  where  its 
durability  is  not  thought  important.  The  last  remark  applies  chiefly  to 
the  Moor-park  apricot  *. 

When  great  difficulty  is  found  in  making  a  tree,  whether  fructiferous, 
or  ornamental,  of  any  species,  or  variety,  produce  blossoms,  or  in  making 
its  blossoms  set  when  produced,  success  will  probably  be  obtained  in 
almost  all  cases,  by  budding  or  grafting  upon  a  stock  which  is  nearly 
enough  allied  to  the  graft  to  preserve  it  alive  for  a  few  years,  but  not 
permanently.  The  pear-tree  affords  a  stock  of  this  kind  to  the  apple  ; 
and  I  have  obtained  a  heavy  crop  of  apples  from  a  graft  which  had  been 
inserted  in  a  tall  pear  stock,  only  twenty  months  previously,  in  a  season 
when  every  blossom  of  the  same  variety  of  fruit  in  the  orchard  was 
destroyed  by  frost.  The  fruit  thus  obtained  was  externally  perfect,  and 
possessed  all  its  ordinary  qualities  ;  but  the  cores  were  black  and  without 
a  single  seed ;  and  every  blossom  had  certainly  fallen  abortively,  if  it  had 
been  growing  upon  its  native  stock.  The  experienced  gardener  will 
readily  anticipate  the  fate  of  the  graft :  it  perished  in  the  following 
winter.  The  stock,  in  such  cases  as  the  preceding,  promotes,  in  propor- 
tion to  its  length,  the  early  bearing  and  early  death  of  the  graft. 

The  authority  of  Duhamel  gives  us  reason  to  believe,  that  the  defects 
of  particular  soils  may  be  remedied  by  a  proper  selection  of  stocks  ;  and 
that  cases  may  occur,  in  which  it  will  be  eligible  to  bud  the  peach  and 
nectarine  upon  the  apricot  or  plum.  My  own  experience  induces  me  to 
think  very  highly  of  the  excellence  of  the  apricot  stock,  for  the  peach  or 
nectarine ;  but  wherever  that,  or  the  plum  stock  is  employed,  I  am 
confident  the  bud  cannot  be  inserted  too  near  the  ground,  when  vigorous 
and  durable  trees  are  wanted.  The  opinion  of  Mr.  Wilmot,  in  a  former 
volume  of  our  Transactions  t,  is,  upon  this  point,  opposed  to  mine  ;  but  I 

*  The  Abricot-Peche,  or  Abricot  de  Nancy,  of  the  French. 
t  Horticultural  Transactions,  Vol.  I.  page  216. 


THE    EFFECTS    OF    DIFFERENT    KINDS    OF    STOCKS    IN    GRAFTING.  223 

speak  upon  the  evidence  of  long  experience,  and  of  experiments  accurately 
and  purposely  made  with  my  own  hands. 

The  form  and  habit  which  a  peach-tree  of  any  given  variety  is  disposed 
to  assume,  I  find  to  be  very  much  influenced  by  the  kind  of  stock  upon 
which  it  has  been  budded  :  if  upon  a  plum  or  apricot  stock,  its  stem  will 
increase  in  size  considerably,  as  its  base  approaches  the  stock,  and  it  will 
be  much  disposed  to  emit  many  lateral  shoots,  as  always  occurs  in  trees 
whose  stems  taper  considerably  upwards ;  and,  consequently,  such  a  tree 
will  be  more  disposed  to  spread  itself  horizontally,  than  to  ascend  to  the 
top  of  the  wall,  even  when  a  single  stem  is  suffered  to  stand  perpendi- 
cularly upwards.  When,  on  the  contrary,  a  peach  is  budded  upon  the 
stock  of  a  cultivated  variety  of  its  own  species,  the  stock  and  the  budded 
stem  remain  very  nearly  of  the  same  size  at,  as  well  as  above  and  below, 
the  point  of  their  junction.  No  obstacle  is  presented  to  the  ascent,  or 
descent,  of  the  sap,  which  appears  to  ascend  more  abundantly  to  the 
summit  of  the  tree.  It  also  appears  to  flow  more  freely  into  the  slender 
branches,  which  have  been  the  bearing  wood  of  preceding  years  :  and 
these  consequently  extend  themselves  very  widely,  comparatively  with 
the  bulk  of  the  stock  and  large  branches. 

When  a  stock  of  the  same  species  with  the  graft  or  bud,  but  of  a 
variety  far  less  changed  by  cultivation,  is  employed,  its  effects  are  very 
nearly  allied  to  those  produced  by  a  stock  of  another  species,  or  genus  : 
the  graft,  generally,  overgrows  its  stock ;  but  the  form  and  durability 
of  the  tree  are  generally  less  affected,  than  by  a  stock  of  a  different 
species  or  genus. 

Many  gardeners  entertain  an  opinion,  that  the  stock  communicates  a 
portion  of  its  own  power  to  bear  cold,  without  injury  to  the  species,  or 
variety  of  fruit,  which  is  grafted  upon  it :  but  I  have  ample  reason  to 
believe,  that  this  opinion  is  wholly  erroneous  :  and  this  kind  of  hardiness 
in  the  root  alone  can  never  be  a  quality  of  any  value  in  a  stock ;  for  the 
branches  of  every  species  of  tree  are  much  more  easily  destroyed  by  frost, 
than  its  roots.  Many  also  believe,  that  a  peach-tree,  when  grafted  upon 
its  native  stock,  very  soon  perishes ;  but  my  experience  does  not  further 
support  this  conclusion,  than  that  it  proves  seedling  peach-trees,  when 
growing  in  a  very  rich  soil,  to  be  greatly  injured,  and  often  killed,  by  the 
excessive  use  of  the  pruning-knife  upon  their  branches,  when  those  are 
confined  to  too  narrow  limits.  The  stock,  in  this  instance,  can,  I  conceive, 
only  act  injuriously  by  supplying  more  nutriment  than  can  be  expended ; 
for  the  root  which  nature  gives  to  each  seedling  plant  must  be  well,  if  not 
best,  calculated  to  support  it ;  and  the  chief  general  conclusions  which 


224  THE    EFFECTS    OF    DIFFERENT    KINDS    OF    STOCKS    IN    GRAFTING. 

my  experience  has  enabled  me  safely  to  draw,  are,  that  a  stock  of  a 
species,  or  genus,  different  from  that  of  the  fruit  to  be  grafted  upon  it, 
can  rarely  be  used  with  advantage,  unless  where  the  object  of  the  planter 
is  to  restrain  and  to  debilitate:  and  that  where  stocks  of  the  same 
species  with  the  bud,  or  graft,  are  used,  it  will  generally  be  found 
advantageous  to  select  such  as  approximate  in  their  habits,  and  state  of 
change,  or  improvement,  from  cultivation,  those  of  the  variety  of  fruit 
which  they  are  intended  to  support. 


XXXIII.— ON  THE   VENTILATION   OF  FORCING-HOUSES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  7th,  1816.] 

IN  a  memoir  which  I  had  two  years  ago  the  honour  to  address  to  the 
Horticultural  Society  *,  I  stated  an  opinion  that  the  gardener  often 
erred  in  the  application  of  heat,  by  treating  his  plants  as  he  would  wish 
to  be  himself  treated,  and  consequently  by  keeping  them  much  too  warm 
during  the  night,  Experiments,  made  previously  and  subsequently  to 
that  period,  have  satisfied  me  that  he  as  often  and  as  widely  errs  by  too 
freely  admitting  the  external  air  during  the  day,  particularly  in  bright 
weather.  Plants  generally  grow  best,  and  fruits  swell  most  rapidly,  in  a 
warm  and  moist  atmosphere ;  and  change  of  air  is,  to  a  very  limited 
extent,  necessary  or  beneficial.  The  mature  leaves  of  plants,  and, 
according  to  Saussure,  the  green  fruits,  (grapes  at  least),  when  exposed 
to  the  influence  of  light,  take  up  carbon  from  the  surrounding  air,  whilst 
the  same  substance  is  given  out  by  every  other  part  of  the  plant ;  so  that 
the  purity  of  air  when  confined  in  close  vessels  has  often  been  found  little 
changed  at  the  end  of  two  or  three  days  by  the  growth  of  plants  in  it. 
But  even  if  plants  required  as  pure  air  as  hot-blooded  animals,  the  buoy- 
ancy of  the  heated  air.  in  every  forcing-house,  would  occasion  it  to 
escape,  and  change  as  rapidly,  and  indeed  much  more  rapidly,  than  would 
be  necessary. 

It  may  be  objected  that  plants  do  not  thrive,  and  that  the  skins  of 
grapes  are  thick,  and  other  fruits  without  flavour,  in  crowded  forcing- 
houses  ;  but  in  these  it  is  probably  light,  rather  than  a  more  rapid  change 
of  air,  that  is  wanting ;  for  in  a  forcing-house,  which  I  have  long  devoted 
almost  exclusively  to  experiments,  I  employ  very  little  fire-heat;  and 
never  give  air,  till  my  grapes  are  nearly  ripe,  in  the  hottest  and  brightest 

*  See  page  213. 


ON    THE    VENTILATION    OF    FORCING-HOUSES.  225 

weather,  further  than  is  just  necessary  to  prevent  the  leaves  being 
destroyed  by  excess  of  heat.  Yet  this  mode  of  treatment  does  not  at  all 
lessen  the  flavour  of  the  fruit,  nor  render  the  skins  of  the  grapes  thick ; 
on  the  contrary,  their  skins  are  always  most  remarkably  thin,  and  very 
similar  to  those  of  grapes  which  have  ripened  in  the  open  air.  It  is 
always  my  wish  to  see  the  temperature  of  this  house,  in  the  middle  of 
every  bright  day  in  summer,  as  high  as  90° ;  and,  after  the  leaves  of  the 
plants  have  become  dry,  I  do  not  object  to  ten  or  fifteen  degrees  higher. 
In  the  following  night  the  temperature  sometimes  falls  as  low  as  50°;  and 
so  far  am  I  from  thinking  such  change  of  temperature  injurious,  I  am  well 
satisfied  that  it  is  generally  beneficial. 

Plants,  it  is  true,  thrive  well,  and  many  species  of  fruits  acquire  their 
greatest  state  of  perfection  in  some  situations  within  the  tropics,  where 
the  temperature,  in  the  shade,  does  not  vary  in  the  day  and  night  more 
then  seven  or  eight  degrees ;  but  in  these  climates  the  plant  is  exposed 
during  the  day  to  the  full  blaze  of  a  tropical  sun,  and  early  in  the  night 
it  is  regularly  drenched  with  heavy-wetting  dews  ;  and  consequently  it  is 
very  differently  circumstanced  in  the  day  and  in  the  night,  though  the 
temperature  of  the  air  in  the  shade  at  both  periods  may  be  very  nearly 
the  same.  If  the  thermometer,  under  the  above-mentioned  circum- 
stances, were  to  be  exposed,  as  the  plant  is,  to  the  sun,  it  would  probably 
indicate,  in  the  middle  of  the  day,  a  temperature  little  below  that  of 
boiling  water.  In  the  forcing-house  so  much  light  and  heat  are  repelled 
by  the  glass  and  wood-work  of  the  roof,  that  the  degree  of  heat  to  which 
the  leaves  are  subjected  does  not  greatly  exceed  that  indicated  by  the 
shaded  thermometer ;  and,  by  excess  of  ventilation,  I  have  several  times 
found  the  temperature  of  forcing-houses  in  the  gardens  of  some  of  my 
friends  reduced  so  nearly  to  that  of  the  external  air  in  the  middle  of  a 
bright,  but  not  very  warm  day,  that  the  progress  towards  maturity  of 
the  fruit  was  certainly  rather  retarded  by  the  shade  than  accelerated  by 
the  protection  of  the  glass  roof.  During  the  night  the  loss,  as  far  as 
related  to  time,  was  probably  redeemed  by  the  flues ;  but  the  fruit  thus 
ripened  during  the  night  never  rivals  in  flavour  that  which  is  chiefly 
ripened  by  confined  solar  heat.  This  kind  of  heat  can  also  be  made  to 
operate  in  every  moderately  bright  day  without  incurring  either  expense 
or  increased  trouble  ;  for  any  observant  gardener  will  soon  discover 
precisely  to  what  extent  air  may  be  confined  in  differently  constructed 
forcing-houses  in  every  different  state  of  the  atmosphere  and  weather, 
and  thus  guard  in  his  absence,  for  a  short  time,  against  all  danger  of 
injury  to  the  foliage  of  his  trees  ;  at  the  same  time  that  these  may  be 

Q 


226 


ON    THE    VENTILATION    OF    FORCING-HOUSES. 


placed  securely  in  nearly  the  highest  temperature  that  can  be  beneficial 
to  them. 

A  less  humid  atmosphere  is  more  advantageous  to  fruits  of  all  kinds, 
when  the  period  of  their  maturity  approaches,  than  in  the  earlier 
stages  of  their  growth,  and  such  an  increase  of  ventilation,  at  this  period, 
as  will  give  the  requisite  degree  of  dryness  to  the  air  within  the  house  is 
highly  beneficial ;  provided  it  be  not  increased  to  such  an  extent  as  to 
reduce  the  temperature  of  the  house  much  below  the  degree  in  which 
the  fruit  has  previously  grown,  and  thus  retard  its  progress  to  maturity. 
The  good  effect  of  opening  a  peach-house,  by  taking  off  the  lights  of  its 
roof  during  the  period  of  the  last  swelling  of  the  fruit,  appears  to  have 
led  many  gardeners  to  overrate  greatly  the  beneficial  influence  of  a  free 
current  of  air  upon  ripening  fruits  ;  for  I  have  never  found  ventilation 
to  give  the  proper  flavour  or  colour  to  a  peach,  unless  that  fruit  was  at 
the  same  time  exposed  to  the  sun  without  the  intervention  of  glass ;  and 
the  most  excellent  peaches  I  have  ever  been  able  to  raise,  were  obtained 
under  circumstances  where  change  of  air  was  as  much  as  possible  prevented 
consistently  with  the  admission  of  light  (without  glass)  to  a  single  tree. 


XXXIV.-UPON    THE    PROPER    MODE    OF    PRUNING    THE    PEACH-TREE, 
IN    COLD    AND    LATE    SITUATIONS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  6th,  1817.] 

THE  buds  of  fruit-trees,  which  produce  blossoms,  and  those  which 
afford  leaves  only,  in  the  spring,  do  not  at  all  differ  from  each  other, 
in  their  first  state  of  organisation,  as  buds.  Each  contain  the  rudiments 
of  leaves  only,  which  are  subsequently  transformed  into  the  component 
parts  of  the  blossom,  and  in  some  species  of  the  fruit  also.  I  have 
repeatedly  ascertained,  that  a  blossom  of  a  pear  or  apple  tree  contains 
parts,  which  previously  existed  as  the  rudiments  of  five  leaves,  the  points 
of  which  subsequently  form  the  five  segments  of  the  calyx ;  and  I  have 
often  succeeded  in  obtaining  every  gradation  of  monstrosity  of  form, 
from  five  congregated  leaves,  (that  is,  five  leaves  united  circularly  upon 
an  imperfect  fruit-stalk),  to  the  perfect  blossom  of  the  pear-tree.  The 
calyx  of  the  rose,  in  some  varieties,  presents  nearly  the  perfect  leaves  of 
the  plant,  and  the  large  and  long  leaves  of  the  medlar  appear  to  account 
for  the  length  of  the  segments,  in  the  empalement  of  its  blossom.  The 
calyx  of  the  blossom  of  the  plum  and  peach  tree  is  formed  precisely 


ON    THE    PROPER    MODE    OF    PRUNING    THE    PEACH-TREE.  227 

as  in  the  preceding  cases,  except  that  the  leaves,  which  are  transmuted 
into  the  calyx,  separate  at  the  base  of  the  fruit  and  become  deciduous, 
instead  of  passing  through  and  remaining  a  component  part  of  it. 

Every  bunch  of  grapes  commences  its  formation  as  a  tendril,  and  it  is 
always  within  the  power  of  every  cultivator  to  occasion  it  to  remain  a 
tendril.  The  blossoms  are  all  additions,  the  formation  of  which  is  always 
dependent  upon  other  agents  :  and  if  any  considerable  part  of  the  leaves 
be  taken  off  the  branch  prematurely,  or  if  the  vine  be  not  subjected  to 
the  influence  of  the  requisite  degree  of  heat  and  light,  the  tendrils  will 
permanently  retain  their  primary  form  and  office ;  and  it  is  very 
frequently  observable,  when  much  of  the  foliage  of  fruit-trees  has  been 
destroyed  by  insects,  or  when  the  previous  season  has  been  cold  and  wet, 
that  blossoms  are  not  formed  at  all,  or  are  feeble  and  imperfect,  and  con- 
sequently abortive.  The  state  of  the  peach-trees  and  vines,  in  every  part, 
or  nearly  every  part  of  the  kingdom,  in  the  present  spring,  has  afforded, 
I  believe,  more  than  sufficient  evidence  of  the  truth  of  the  last  position. 

It  is,  I  conceive,  quite  unnecessary  to  adduce  arguments  to  prove  that 
the  buds,  which  are  first  formed  in  the  spring,  are  most  likely  to  undergo 
properly  the  necessary  internal  changes  of  structure  above-mentioned, 
and  consequently  to  afford  more  perfectly  organised  blossoms,  than  such 
as  are  not  formed  before  the  middle  of  the  summer,  or  till  near  the 
approach  of  autumn ;  and  if  this  be  admitted,  it  will  not  be  difficult 
to  show,  that  the  mode  of  pruning  and  training  the  peach-tree,  which 
has  been  uniformly  recommended,  and  almost  as  uniformly  practised,  is 
well  adapted  to  favourable  situations  only.  It  has  been  derived  from  the 
practice  of  the  French  gardeners,  and  is  probably  perfectly  well  suited 
to  the  climate  of  Paris,  but  by  no  means  so  well  calculated  (I  have,  I 
think,  very  good  reason  to  believe)  for  the  colder  parts  of  England,  as 
that  I  proceed  to  describe  and  recommend. 

Every  tree  prepares  in  the  summer  and  autumn  many  minute  leaves, 
which  expand  and  form  the  early  foliage  of  the  following  spring,  and  the 
buds  in  the  axillse  of  these  leaves  are  necessarily  (consistent  with  the 
preceding  statements,)  those  best  calculated,  in  cold  and  unfavourable 
situations  and  seasons,  to  generate  well  organised  and  vigorous  blossoms; 
and  in  such  situations,  I  have  often  witnessed  the  advantage  of  preserving 
as  many  as  practicable  of  these,  by  deviating  from  the  ordinary  mode  of 
pruning  the  peach-tree.  Instead  of  taking  off  so  large  a  portion  of  the 
young  shoots,  and  training  in  a  few  only,  to  a  considerable  length,  as  is 
usually  done,  and  as  I  should  myself  do  to  a  great  extent,  in  the  vicinity 
of  London,  and  in  every  favourable  situation,  I  preserve  a  large  number 

Q2 


228  ON    THE    PROPER    MODE    OF    PRUNING    THE    PEACH-TREE. 

of  the  young  shoots,  which  are  emitted  in  a  proper  direction  in  early 
spring  by  the  yearling  wood,  shortening  each  where  necessary,  by  pinch- 
ing off  the  minute  succulent  points,  generally  to  the  length  of  one  or  two 
inches.  Spurs  which  lie  close  to  the  wall  are  thus  made,  upon  which 
numerous  blossom  buds  form  very  early  in  the  ensuing  summer;  and 
upon  such,  after  the  last  most  unfavourable  season,  and  in  a  situation  so 
high  and  cold  that  the  peach-tree,  in  the  most  favourable  seasons,  had 
usually  produced  only  a  few  feeble  blossoms,  I  observed  as  strong  and 
vigorous  blossoms  in  the  present  spring,  as  I  have  usually  seen  in  the 
best  seasons  and  situations ;  and  I  am  quite  confident  that  if  the  peach- 
trees,  in  the  gardens  round  the  metropolis,  had  been  pruned  in  the 
manner  above  described,  in  the  last  season,  an  abundant  and  vigorous 
blossom  would  have  appeared  in  the  present  spring.  I  do  not,  however, 
mean  to  recommend  to  the  gardener  to  trust  wholly,  in  any  situation,  for 
his  crop  of  fruit,  to  the  spurs  produced  by  the  above-mentioned  mode  of 
pruning  and  training  the  peach-tree.  In  every  warm  and  favourable 
situation,  I  would  advise  him  to  train  the  larger  part  of  his  young  wood, 
according  to  the  ordinary  method,  and  in  cold  and  late  situations  only,  to 
adopt  to  a  great  extent,  the  mode  of  management  above  suggested.  A 
mixture  of  both  modes,  in  every  situation,  will  be  generally  found  to 
multiply  the  chances  of  success;  and  therefore  neither  ought  to  be 
exclusively  adopted,  or  wholly  rejected  in  any  situation.  The  spurs  must 
not  be  shortened  in  the  winter  or  spring,  till  it  can  be  ascertained  what 
parts  of  them  are  provided  with  leaf-buds. 


XXXV.— OBSERVATIONS  ON  THE  PROPER  MANAGEMENT  OF  FRUIT- 
TREES,  WHICH  ARE  INTENDED  TO  BE  FORCED  VERY  EARLY  IN 
THE  ENSUING  SEASON. 

[Read  before  the  HORTICULTURAL  SOCIETY,  June  3rd,  1817.] 

THE  period  which  any  species,  or  variety,  of  fruit  will  require  to  attain 
maturity,  under  any  given  degrees  of  temperature,  and  exposure  to  the 
influence  of  light  in  the  forcing-house,  will  be  regulated  to  a  much  greater 
extent  than  is  generally  imagined,  by  the  previous  management  and 
consequent  state  of  the  tree,  when  that  is  first  subjected  to  the  operation 
of  artificial  heat.  Every  gardener  knows,  that  when  the  previous  season 
has  been  cold,  and  cloudy,  and  wet,  the  wood  of  his  fruit-trees  remains 
immature,  and  weak  abortive  blossoms  only  are  produced.  The  advan- 
tages of  having  the  wood  well  ripened  are  perfectly  well  understood ; 


ON    THE    MANAGEMENT    OF    FRUIT-TREES    INTENDED    FOR    FORCING.         229 

but  those  which  may  be  obtained,  whenever  a  very  early  crop  of  fruit  is 
required,  by  ripening  the  wood  very  early  in  the  preceding  summer,  and 
putting  the  tree  into  a  state  of  repose,  as  soon  as  possible  after  its  wood 
has  become  perfectly  mature,  do  not,  as  far  as  my  observation  has 
extended,  appear  to  be  at  all  known  to  gardeners ;  though  every  one 
who  has  had  in  any  degree  the  management  of  vines  in  a  hot-house, 
must  have  observed  the  different  effects  of  the  same  degrees  of  tem- 
perature upon  the  same  plant,  in  October  and  February.  In  the 
autumn,  the  plants  have  just  sunk  into  their  winter  sleep :  in  February 
they  are  refreshed,  and  ready  to  awake  again  ;  whenever  it  is  intended 
prematurely  to  excite  their  powers  of  life  into  action,  the  expediency 
of  putting  these  powers  into  a  state  of  rest,  early  in  the  preceding 
autumn,  appears  obvious.  The  natural  propensity  of  the  gardener  to 
treat  his  plants  as  in  some  degree  sentient  beings,  and  as  he  would 
wish  to  be  himself  treated,  which  sometimes  misleads  him  (as  I  have 
remarked  in  a  former  paper)*,  will  in  this  case  direct  him  rightly, 
by  leading  him  to  infer,  that  early  rising  requires  early  going  to  rest. 
I  shall  therefore  state  the  result  of  a  few  experiments  only,  which  will,, 
I  believe,  afford  satisfactory  evidence  of  the  truth  of  the  foregoing 
positions. 

Some  vines,  which  grew  in  pots,  were  placed  in  a  forcing-house,  at  the 
end  of  January,  where  they  produced  ripe  fruit  about  the  middle  of 
July ;  and  soon  after  that  period,  the  pots  were  taken  from  the  house 
and  put  under  the  shade  of  a  north  wall,  in  the  open  air.  Water  was 
subsequently  given  in  small  quantities  only  ;  and  the  leaves  of  the  plants 
soon  fell  off.  In  August  the  plants  were  pruned ;  and  in  September 
they  were  removed  to  a  south  wall,  where  they  soon  vegetated  with  much 
vigour,  and  continued  to  grow  till  their  young  shoots  were  killed  by 
frost. 

Other  vines,  of  the  same  varieties,  were  suffered  to  remain  in  the 
forcing-house  till  late  in  August ;  where  they  were  subjected  to  the  mode 
of  management  above  described,  except  that  they  were  not  removed 
from  their  situation  under  a  north  wall,  nor  pruned,  before  the  approach 
of  winter.  These  were  then  placed  against  a  south  wall,  where  their 
fruit  ripened  well  in  the  following  season,  in  a  climate  not  nearly  warm 
enough  to  have  ripened  it  at  all,  if  the  plants  had  previously  grown  in 
the  open  air. 

Having  raised  many  varieties  of  the  peach  from  seed  in  the  year  1813, 
I  felt  anxious  to  secure  the  existence  of  each  variety  till  I  could  ascertain 

*  See  page  213. 


230        ON    THE    MANAGEMENT    OF    FRUIT-TREES    INTENDED    FOR    FORCING. 

its  merits  ;  and  with  this  view,  I  obtained  a  duplicate  of  each  by  inserting 
a  bud  from  every  seedling  plant  into  a  stock,  which  I  placed  in  the 
forcing-house.  Late  in  the  autumn  of  the  year  1815,  some  of  the  young 
trees,  which  had  been  obtained  from  these  buds,  were  removed  from  the 
forcing-house,  in  which  their  wood  had  become  most  perfectly  well 
ripened,  in  the  preceding  summer,  to  the  open  air,  and  were  placed,  as 
closely  as  could  conveniently  bo  done,  to  the  seedling  trees  of  the  same 
varieties,  which  had  grown  wholly  in  the  open  air  :  and  thus  circum- 
stanced, the  blossoms  of  the  trees  which  had  been  removed  from  the 
forcing-house  unfolded  nine  days  earlier,  and  their  fruit  ripened  three 
weeks  earlier,  than  those  upon  the  other  trees  of  the  same  varieties. 

The  confinement  of  the  roots  to  pots,  and  possibly,  to  a  small  extent, 
the  influence  of  the  stock  (for  the  peach-trees  in  the  pots  grew  upon 
apricot  shoots),  may  have  somewhat  accelerated  the  maturity  of  the 
fruit  in  the  experiment  last  mentioned  ;  but  the  chief  causes  of  the  early 
maturity  of  the  fruit  in  both  the  preceding  cases  were,  I  am  confident, 
the  perfect  maturity  of  the  wood,  and  the  high  state  of  excitability,  which 
had  been  acquired  by  a  preternaturally  long  period  of  rest. 

It  is  not,  I  believe,  at  all  necessary  that  I  should  offer  arguments  to 
prove  that  a  vine,  which  cannot  be  made  to  vegetate  at  all  in  the 
winter  without  a  very  high  degree  of  heat,  is  not  as  well  calculated  for 
very  early  forcing  as  one  in  which  the  powers  of  life  are  so  excitable  that 
it  is  prepared  to  vegetate  strongly  in  the  temperature  of  the  open  air  in 
September,  arid  in  which  the  power  to  vegetate  in  a  low  temperature 
will  continue  to  accumulate  progressively  till  spring  :  but  it  will  probably 
be  objected  that  as  large  a  crop  cannot  be  obtained  from  vines  of  which 
the  roots  are  confined  in  pots,  as  from  others.  This  objection,  however, 
will,  I  believe,  prove  to  be  wholly  unfounded,  whenever  a  very  early  crop 
is  wanted  ;  for  vines  and  other  fruit-trees  (as  I  have  observed  in  former 
papers)  when  abundantly  supplied  with  water,  and  manure  in  a  liquid 
state,  require  but  a  very  small  quantity  of  mould.  A  pot  containing  two 
cubic  feet  of  very  rich  mould,  with  proper  subsequent  attention,  is  fully 
adequate  to  nourish  a  vine  which,  after  being  pruned  in  autumn,  occupies 
twenty  square  feet  of  the  roof  of  a  hot-house  ;  and  I  have  constantly 
found  that  vines,  in  such  pots,  being  abundantly  supplied  with  food  and 
water,  have  produced  more  vigorous  wood,  when  forced  very  early,  than 
others  of  the  same  varieties,  whose  roots  were  permitted  to  extend 
beyond  the  limits  of  the  house. 


231 


XXXVI.— UPON    THE    PROPAGATION    OF     VARIETIES     OF    THE    WALNUT- 
TREE,   BY    BUDDING. 

[Read  before  the  HORTICULTURAL  SOCIETY,  April  1th,  1818.] 

THE  ill  success  of  many  attempts  to  propagate  the  walnut-tree  by  grafts, 
or  buds,  led  me,  in  a  former  communication,  to  discourage  all  attempts 
to  increase  it,  except  by  seeds,  or  by  grafting  by  approach.  I  never- 
theless continued,  annually,  to  make  a  few  experiments,  with  the  hope  of 
discovering  a  method  of  budding,  which  would  prove  successful  in  the 
culture  of  varieties  of  this  fruit,  and  of  others  of  equally  difficult  pro- 
pagation ;  and  I  have  found,  in  ultimate  success,  the  usual  reward  of 
patient  perseverance. 

The  advantages  of  propagating  varieties  of  the  walnut-tree,  by  bud- 
ding, will,  I  think  be  found  considerable,  provided  the  buds  be  taken 
from  young,  or  even  middle-aged  healthy  trees :  for,  exclusive  of  the 
advantage  of  obtaining  fruit  from  very  young  trees,  the  planter  will  be 
enabled  to  select  not  only  such  varieties  as  afford  the  best  fruit,  but  also 
such  as  endure  best,  as  timber- trees,  the  vicissitudes  of  our  climate. 
In  this  respect  some  degree  of  difference  is  almost  always  observable  in 
the  constitution  of  each  individual  seedling  tree  ;  and  this  is  invariably 
transferred  with  the  graft  or  bud. 

The  walnut,  it  is  true,  as  a  fruit,  contains  but  little  nutriment,  and 
perhaps  constitutes,  at  best,  only  an  unwholesome  luxury :  but  the  tree 
affords  timber  of  much  greater  strength  and  elasticity,  comparatively 
with  its  very  low  specific  gravity,  than  any  other  of  British  growth,  and 
it  is  consequently  applicable  to  purposes  for  which  no  good  substitute  has 
hitherto  been  found ;  the  stocks  of  the  musket  of  the  soldier,  and  of  the 
gun  of  the  sportsman. 

The  buds  of  trees,  of  almost  every  species,  succeed  with  most  certainty, 
when  inserted  in  the  shoots  of  the  same  year's  growth ;  but  the  walnut- 
tree  appears  to  afford  an  exception ;  possibly  in  some  measure  because  its 
buds  contain,  within  themselves,  in  the  spring,  all  the  leaves  which  the 
tree  bears  in  the  following  summer ;  whence  its  annual  shoots  wholly 
cease  to  elongate  soon  after  its  buds  unfold  ;  all  its  buds  of  each  season 
are  also,  consequently,  very  nearly  of  the  same  age :  and  long  before 
any  have  acquired  the  proper  degree  of  maturity  for  being  removed,  the 
annual  branches  have  ceased  to  grow  longer,  or  to  produce  new  foliage. 

To  obviate  the  disadvantages  arising  from  the  preceding  circumstances, 
I  adopted  means  of  retarding  the  period  of  the  vegetation  of  the  stocks, 


232  UPON    THE    PROPAGATION    OF    THE    WALNUT-TREE. 

comparatively  with  that  of  the  bearing  tree :  and  by  these  means  I 
became  partially  successful.  There  are  at  the  base  of  the  annual  shoots 
of  the  walnut,  and  other  trees,  where  those  join  the  year-old  wood,  many 
minute  buds ;  which  are  almost  concealed  in  the  bark  ;  and  which  rarely, 
or  never  vegetate,  but  in  the  event  of  the  destruction  of  the  large  pro- 
minent buds,  which  occupy  the  middle,  and  opposite  end  of  the  annual 
wood.  By  inserting  in  each  stock  one  of  these  minute  buds,  and  one  of 
the  large  and  prominent  kind,  I  had  the  pleasure  to  find  that  the  minute 
buds  took  freely,  whilst  the  large  all  failed,  without  a  single  exception. 
This  experiment  was  repeated  in  the  summer  of  1815,  upon  two  yearling 
stocks  which  grew  in  pots,  and  had  been  placed  during  the  spring 
early  part  of  the  summer,  in  a  shady  situation  under  a  north  wall ; 
whence  they  were  moved  late  in  July  to  a  forcing-house,  which  I  devote 
to  experiments,  and  instantly  budded.  These  being  suffered  to  remain 
in  the  house  during  the  following  summer,  produced  from  the  small  buds, 
shoots  nearly  three  feet  long  terminating  in  large  and  perfect  female 
blossoms,  which  necessarily  proved  abortive,  as  no  male  blossoms  were 
procurable  at  the  early  period  in  which  the  female  blossoms  appeared : 
but  the  early  formation  of  such  blossoms  sufficiently  proves  that  the 
habits  of  a  bearing  branch  of  the  walnut-tree  may  be  transferred  to  a 
young  tree  by  budding,  as  well  as  grafting  by  approach. 

The  most  eligible  situation  for  the  insertion  of  buds  of  this  species 
of  tree  (and  probably  of  others  of  similar  habits)  is  near  the  summit 
of  the  wood  of  the  preceding  year,  and  of  course,  very  near  the  base  of 
the  annual  shoot ;  and  if  buds  of  the  small  kind  above-mentioned,  be 
skilfully  inserted  in  such  parts  of  branches  of  rapid  growth,  they  will  be 
found  to  succeed  with  nearly  as  much  certainty  as  those  of  other  fruit- 
trees,  provided  such  buds  be  in  a  more  mature  state  than  those  of  the 
stocks  into  which  they  are  inserted. 

The  advantages  which  may  be  obtained  in  the  propagation  of  other 
species  of  trees  by  procuring  buds  for  insertion  in  a  more  mature  state 
than  those  of  the  stock,  are  sufficient  to  deserve  some  attention,  and 
are  not,  I  believe,  at  all  known  to  gardeners  and  nurserymen.  The 
mature  bud  takes  immediately  with  more  certainty  under  the  same 
external  circumstances :  it  is  much  less  liable  to  perish  during  winter ; 
and  it  possesses  the  valuable  property  of  rarely  or  never  vegetating 
prematurely  in  the  summer,  though  it  be  inserted  before  the  usual 
period,  and  in  the  season  when  the  sap  of  the  stock  is  most  abundant. 
I  have,  in  different  years,  removed  some  hundred  buds  of  the  peach- 
tree  from  the  forcing-house  to  luxuriant  shoots  upon  the  open  wall ; 


UPON    THE    PROPAGATION    OF    THE    WALNUT-TREE.  233 

and  I  have  never  seen  an  instance  in  which  any  of  such  buds  have 
broken  and  vegetated  during  the  summer  or  autumn ;  but  when  I  have 
had  occasion  to  reverse  this  process,  and  to  insert  immature  buds 
from  the  open  wall  into  the  branches  of  trees  growing  in  a  peach-house, 
many  of  these,  and  in  some  seasons  all,  have  broken  soon  after  being 
inserted,  though  at  the  period  of  their  insertion  the  trees  in  the  peach- 
house  had  nearly  ceased  to  grow.  The  result  was,  in  both  the  pre- 
ceding cases,  in  opposition  to  my  expectations ;  but  it  appears  neces- 
sarily to  have  been  occasioned  by  the  mature  bud  having  naturally 
sunk  into  a  state  of  repose  preparatory  to  its  long  winter  sleep,  pre- 
viously to  its  having  been  removed  ;  and  by  the  more  excitable  state 
of  the  powers  of  life  in  the  bud  taken  from  the  open  wall. 

If  the  mature  buds  of  the  peach-tree,  when  taken  from  the  forcing- 
house,  contain  blossoms,  these  may  be  carried  a  great  distance,  and 
still  afford  fruit  in  the  following  spring.  I  have  thus  readily  obtained 
fruit  from  blossoms  sent  me  from  the  vicinity  of  London  ;  and  I  entertain 
no  doubt  of  the  practicability  of  obtaining  fruit  from  blossoms  sent 
from  Paris,  or  even  from  the  south  of  France,  if  properly  packed.  In 
such  cases  it  wrould  be  necessary  to  pare  the  wood  of  the  bud  thin, 
instead  of  wholly  extracting  it :  and  this  will  sometimes  be  found 
expedient,  when  buds  are  to  be  taken  from  a  peach-house,  in  which 
the  fruit  has  been  made  to  ripen  early  in  the  summer,  to  be  inserted 
in  the  open  air. 


XXXVII.— UPON    THE    PRUNING  AND    MANAGEMENT   OF   TRANSPLANTED 

STANDARD   TREES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  June  2nd,  1818.] 

WHEN  a  tree  is  transplanted,  it  loses,  almost  necessarily,  a  considerable 
part  of  its  roots  :  and  as  these,  in  every  healthy  subject,  are  nicely  pro- 
portioned to  the  branches,  the  advantages  of  retrenching  the  latter  are 
obvious,  and  well  known  to  every  gardener.  But  relatively  to  the  mode 
of  retrenching  the  branches,  and  the  extent  of  retrenchment  that  is 
beneficial,  there  is  much  discordance  in  the  opinions  and  practice  of 
different  gardeners ;  and  often  still  more  between  the  gardener  and  his 
employer ;  the  latter  wishing  to  preserve  the  bearing  branches,  that  he 
may,  at  an  early  period,  obtain  a  crop  of  fruit ;  and  the  gardener  wishing 
to  head  down  the  tree,  that-  he  may  see  it  shoot  with  vigour.  Neither 


234       UPON    THE    PRUNING    AND    MANAGEMENT    OF    TRANSPLANTED    TREES. 

mode  of  practice  is,  I  think,  in  its  full  extent,  quite  eligible  to  the  greater 
number  of  cases ;  the  one  being  too  prejudicial  to  the  growth  of  the  tree, 
by  occasioning  the  production  prematurely  of  an  unusual  profusion  of 
blossoms  ;  and  the  other  being,  even  when  most  successful,  attended  with 
an  unnecessary  loss  of  time :  and  I  have  found,  in  very  extensive  experi- 
ence, that  transplanted  trees  generally  succeed  permanently  best,  and  as 
standards  take  the  best  forms,  when  their  lateral  branches,  instead  of 
being  suffered  to  retain  their  whole  length,  or  pruned  off  closely,  are  all 
shortened  to  the  length  of  a  few  inches,  and  the  top  of  the  tree  reduced 
to  a  single  annual  shoot.  Under  these  circumstances  the  leaves  become 
dispersed  upon  the  stem,  so  as  to  afford  nutriment  to  the  bark  of  different 
parts  of  it ;  and  the  power  of  the  wind  to  prevent  the  tree  re-establishing 
itself  is  small  (owing  to  the  situation  of  the  leaves),  comparatively  with 
the  extent  of  the  foliage  which  the  tree  exposes  to  light.  The  trees 
under  this  mode  of  treatment  also  bear  as  much  fruit  as  they  are  capable 
of  feeding,  as  soon  as  under  any  other  that  I  have  hitherto  tried  or  seen  ; 
and  within  three  or  four  years  their  branches  generally  become  more 
widely  extended  than  those  of  similar  trees  which  are  planted  without 
being  pruned.  The  same  mode  of  pruning  is  equally  well  adapted  to  fruit 
and  forest  trees ;  and  oaks,  which  I  have  planted  when  ten  or  twelve  feet 
high,  have  not  only  begun  immediately  to  grow  with  luxuriance,  but  they 
have  within  a  very  years  wholly  lost  the  character  of  transplanted  trees. 

The  great  error  of  modern  practice  is  that  of  suffering,  when  the  trees 
are  not  headed  down,  many  small  branches  to  form  the  summit  of  the 
transplanted  tree ;  which  branches  expend  its  sap  in  the  production  of 
tufts  of  leaves,  where  those,  owing  to  their  distance  from  the  roots, 
operate  least  beneficially  in  the  performance  of  their  proper  office,  and 
most  injuriously  by  being  most  exposed  to  the  influence  of  winds. 

Whenever  the  roots  of  transplanted  trees  have  been  very  much  injured, 
or  have  been  very  long  out  of  the  ground,  the  number,  as  well  as  the 
extent  of  the  lateral  branches,  should  be  reduced,  and  not  more  than  a 
few  inches  of  the  leading  annual  shoot  should  be  suffered  to  remain ;  but 
in  all  cases  where  trees  are  to  be  sent  a  great  distance,  this  retrenchment 
of  their  branches  should  be  made  in  the  nursery  from  which  they  are  to 
be  removed ;  and,  if  it  be  properly  executed,  trees  may  be  conveyed  to 
great  distances,  under  more  disadvantageous  circumstances  than  is  usually 
supposed,  without  endangering  life,  provided  they  be  subjected  to  proper 
subsequent  management. 

I  received  in  the  last  spring  some  apple-trees  from  America,  which 
were  forwarded  to  me  from  London  by  a  wrong  waggon,  and  consequently 


UPON    THE    PRUNING    AND    MANAGEMENT    OP    TRANSPLANTED    TREES.      235 

did  not  arrive  till  near  the  middle  of  April,  and  many  weeks  after  the 
period  at  which  I  ought  to  have  received  them.  The  whole  of  them 
appeared  perfectly  lifeless  and  dry,  and  much  better  fitted  for  fire-wood 
than  for  planting  ;  and  I  scarcely  entertained  the  slightest  hope  of  being 
able  to  recover  a  single  plant.  I  nevertheless  resolved  that  no  trouble 
should  be  spared  in  making  the  experiment. 

The  American  nurserymen  had  pruned  the  trees  much  in  the  way  I 
wished  (though  in  a  very  rough  and  careless  manner,  and  obviously  with- 
out any  other  object  than  convenience  in  packing  them) ;  and  I  had 
therefore  little  more  to  do  in  pruning  them  than  to  take  away  such 
branches  as  were  broken  and  wholly  dead.  The  trees,  which  were  about 
four  feet  high,  were  then  planted  in  a  situation  where  they  were  perfectly 
screened  from  the  morning  sun,  and  just  as  much  water  was  given  as  was 
sufficient  to  close  the  moulds  to  the  roots.  Their  stems  were  then 
sprinkled  with  water,  by  an  engine,  sufficiently  to  wet  the  bark ;  and  this 
was  repeated  at  six  o^clock  every  morning  through  the  months  of  May, 
June,  and  July ;  but  no  water  was  given  immediately  to  the  roots, 
previous  experience  having  led  me  to  believe  that  excess  of  moisture  is,  in 
such  cases,  generally  injurious,  and  often  fatal. 

About  midsummer  a  few  of  the  trees  began  to  exhibit  some  feeble 
symptoms  of  life ;  several  subsequently  shot  vigorously,  some  to  the 
length  of  eighteen  inches ;  and  out  of  sixty-four  trees,  I  lost  only  three. 
They  succeeded,  in  the  aggregate,  better  than  other  trees  of  nearly  the 
same  age,  which  were  only  removed  from  a  contiguous  nursery,  but  which 
were  not  sprinkled  with  water ;  the  season  having  proved  cold  and  dry, 
and  consequently  extremely  unfavourable  to  transplanted  trees. 

I  had  previously  seen  in  other  instances,  though  never  in  so  apparently 
hopeless  a  case,  the  good  effects  of  sprinkling  the  stems  and  branches  of 
transplanted  trees  before  the  sun  began  to  shine  upon  them  in  the 
morning,  both  in  the  forcing-house  and  in  the  open  air.  In  the  forcing- 
house  I  have  found  that  water  may  be  also  thus  applied  with  advantage  in 
the  evening  as  well  as  in  the  morning ;  but,  in  the  open  air,  I  have  had 
reason  to  think  its  operation  injurious,  when  the  succeeding  night  has 
proved  cold. 


236 


XXXVIII.— ON  THE  CULTURE  OF  THE  GUERNSEY  LILY. 

[Head  before  the  HORTICULTURAL  SOCIETY,  August  3rd,  1819.] 

A  WISH  has  been  expressed  by  the  Council  of  the  Society,  that  a  method 
of  cultivating  the  Amaryllis  Sarniensis,  or  Guernsey  Lily,  should  be  dis- 
covered, by  which  the  bulbs  of  that  plant  might  be  made  to  afford 
blossoms,  regularly,  through  successive  seasons :  and  I,  in  consequence, 
address  the  following  communication  upon  that  subject ;  believing,  that 
I  can  satisfactorily  account  for  its  sparing  production  of  blossoms  in  our 
climate,  and  point  out  a  mode  of  cultivating  it,  by  which  it  may  be  made 
to  blossom,  much  more  freely  than  it  usually  does,  though  I  have  not 
attained  the  object  desired  by  the  Society. 

Bulbous  roots  increase  in  size,  and  proceed  in  acquiring  powers  to 
produce  blossoms,  only  during  the  periods  in  which  they  have  leaves, 
and  in  which  such  leaves  are  exposed  to  light ;  and  these  organs  always 
operate  most  efficiently  when  they  are  young,  and  have  just  attained 
their  full  growth.  The  bulb  of  the  Guernsey  Lily,  as  it  is  usually  culti- 
vated in  this  country,  rarely  produces  leaves  till  September,  or  the 
beginning  of  October,  at  which  period,  the  quantity  of  light  afforded  by 
our  climate  is  probably  quite  insufficient  for  a  plant,  which  is  said  to  be 
a  native  of  the  warm  and  bright  climate  of  Japan  ;  and  before  the  return 
of  spring,  its  leaves  are  necessarily  grown  old,  and  nearly  out  of  office, 
even  when  they  have  been  safely  protected  from  frost  through  the  winter. 
It  is,  therefore,  not  extraordinary,  that  a  bulb  of  this  species,  which  has 
once  expended  itself  in  affording  flowers,  should  but  very  slowly  recover 
the  power  of  blossoming  again.  The  operation  also  of  a  cold  climate,  in 
retarding  its  period  of  vegetation,  must  have  led  the  plant  into  late 
habits,  like  those  of  the  vines,  described  by  Mr.  Arkw7right,  in  our 
Transactions  * ;  and,  consequently,  instead  of  being  naturalised,  and 
adapted  to  our  climate  as  plants  become,  which  propagate  by  seeds,  it  is, 
probably,  now  less  capable  of  producing  a  regular  annual  succession  of 
blossoms,  than  a  similar  variety  of  the  same  species  of  plant,  immediately 
imported  from  Japan,  would  be. 

Considering,  therefore,  the  deficiency  of  light  and  heat,  owing  to  the 
late  period  of  its  vegetation,  as  the  chief  cause,  why  this  plant  so  fails  to 
produce  flowers,  I  infer  that  nothing  more  would  be  required  to  make  it 
blossom,  as  freely,  at  least,  as  it  does  in  Guernsey,  than  such  a  slight 
degree  of  artificial  heat,  applied  early  in  the  summer,  as  would  prove 

*  See  Horticultural  Transactions,  Vol.  III.  p.  95. 


ON    THE    CULTURE    OF    THE    GUERNSEY    LILY.  237 

sufficient  to  make  the  bulbs  vegetate  a  few  weeks  earlier  than  usual  in 
the  autumn. 

Early  in  the  summer  of  1816,  a  bulb,  which  had  blossomed  in  the 
preceding  autumn,  was  subjected  to  such  a  degree  of  artificial  heat,  as 
occasioned  it  to  vegetate  six  weeks,  or  more,  earlier  than  it  would  other- 
wise have  done.  It  did  not,  of  course,  produce  any  flowers  ;  but  in  the 
following  season,  it  blossomed  early,  and  strongly,  and  afforded  two 
offsets.  These  were  put,  in  the  spring  of  1818,  into  pots,  containing 
about  one-eighth  of  a  square  foot  light  and  rich  mould,  and  were  fed 
with  manured  water,  and  their  period  of  vegetation  was  again  accelerated 
by  artificial  heat.  Their  leaves,  consequently,  grew  yellow  from  matu- 
rity, early  in  the  present  spring,  when  the  pots  were  placed  in  rather  a 
shady  situation,  and  near  a  north  wall,  to  afford  me  an  opportunity  of 
observing  to  what  extent,  in  such  a  situation,  the  early  production  of  the 
leaves  in  the  preceding  seasons  had  changed  the  habit  of  the  plant.  I 
entertained  no  doubt  but  that  both  the  bulbs  would  afford  blossoms,  but 
I  was  much  gratified  by  the  appearance  of  the  blossoms  in  the  first  week 
in  July.  Wishing  to  obtain  seeds,  I  then  removed  the  plants  to  a 
forcing-house,  in  which  they  have  flowered  very  strongly ;  and  the 
appearance  of  the  seed-vessels  gives  much  reason  to  suppose  that  I  shall 
succeed  in  obtaining  seeds,  though  I  am  not  at  present  able  to  speak 
decisively. 

From  the  success  of  the  preceding  experiment,  I  conclude  that  if  the 
offsets,  and  probably  the  bulbs,  of  this  plant  which  have  produced  flowers, 
be  placed  in  a  moderate  hot-bed,  in  the  end  of  May,  to  occasion  the 
early  production  of  their  leaves,  blossoms  would  be  constantly  afforded  in 
the  following  season :  but  it  will  be  expedient  to  habituate  the  leaves, 
thus  produced,  gradually  to  the  open  air,  as  soon  as  they  are  nearly 
full  grown,  and  to  protect  them  from  frost  till  the  approach  of  spring. 

Should  seedling  plants  be  obtained,  the  powers  of  life  in  those,  will 
probably  prove  more  alert :  and  I  think  it  probable,  that,  xvith  a  mode- 
rate degree  of  care,  these  may  be  made  to  afford  blossoms  in  successive 
seasons ;  though  it  should  be  found  impracticable  to  give  that  habit  to 
the  onsets  of  the  individual  seedling  plant,  now  in  cultivation. 


238 


XXXIX.— UPON   THE    EFFECTS    OF  VERY  HIGH  TEMPERATURE    ON    SOME 

SPECIES   OF   PLANTS. 

{Read  before  the  HORTICULTURAL  SOCIETY,  December  7th,  1819.] 

HAVING  constructed  a  forcing-house  for  the  purpose  of  attempting  the 
culture  of  the  mango,  and  a  few  other  species  of  tropical  fruits,  I  have 
endeavoured  to  ascertain,  with  accuracy,  the  advantages  and  disadvan- 
tages, of  employing  very  high  temperature  during  the  day  in  bright 
weather,  and  of  comparatively  low  temperature  during  the  night,  and  in 
cloudy  weather  ;  and  I  communicate  the  following  account  of  my  experi- 
ments, considering  the  results  to  have  been  generally  very  favourable, 
and  where  unsuccessful,  not  wholly  uninteresting. 

A  fire  of  sufficient  power,  only,  to  preserve  in  the  house  a  temperature 
of  about  70°,  during  summer,  was  employed,  but  no  air  was  ever  given, 
nor  its  escape  facilitated,  till  the  thermometer,  perfectly  shaded,  indicated 
a  temperature  of  95° ;  and  then  only  two  of  the  upper  lights,  one  at  each 
end,  were  let  down  about  four  inches.  The  heat  of  the  house  was  conse- 
quently sometimes  raised  to  110°,  during  the  middle  of  warm  and  bright 
days,  and  it  generally  varied,  in  such  days,  from  90°  to  105°,  declining 
during  the  evening  to  about  80°,  and  to  70°  in  the  night. 

Late  in  the  evening  of  every  bright  and  hot  day,  the  plants  were 
copiously  sprinkled  with  water,  nearly  of  the  temperature  of  the  external 
air ;  and  the  following  were  the  effects  produced  upon  the  different 
species. 

The  Melon.  Plants  of  this  species  were  trained  upon  a  trellis  near 
the  glass,  which  was  of  the  best  quality,  and  these  exhibited  a  greater 
degree  of  health  and  luxuriance,  than  I  had  ever  before  seen  ;  but  not  a 
single  flower  ever  unfolded  ;  a  great  profusion  of  minute  blossoms,  never- 
theless, appeared  in  succession  at  the  points  of  the  shoots,  all  of  which 
perished  abortively.  I  was  much  disappointed  at  the  result  of  this 
experiment ;  from  which  I  confidently  expected  to  obtain  fruit  of  the 
greatest  excellence. 

The  Water  Melon.  A  plant  of  this  species,  treated  in  the  same  manner 
as  the  melon  plants  above  mentioned,  grew  with  equal  health  and  luxuri- 
ance, and  afforded  a  most  abundant  blossom ;  but  all  its  flowers  were 
male.  This  result  did  not,  in  any  degree,  surprise  me  ;  for  I  had  many 
years  previously  succeeded,  by  long  continued  very  low  temperature,  in 
making  cucumber  plants  produce  female  flowers  only  ;  and  I  entertain 
but  little  doubt,  that  the  same  fruit-stalks  might  be  made,  in  this  and 


ON    THE    EFFECTS    OF    HIGH    TEMPERATURE    ON    SOME    PLANTS.  239 

the  preceding  species,  to  support  either  male  or  female  flowers,  in 
obedience  to  external  causes. 

The  Guernsey  Lily.  I  transferred  plants  of  this  species,  from  the  open 
air  to  the  hot-house,  in  the  summer,  with  the  hope  of  obtaining  seeds,  in 
which  I  was  wholly  disappointed.  The  flowers  expanded  very  beautifully; 
but  their  pollen  never  shedded-  The  plants  have,  nevertheless,  subse- 
quently grown  with  more  than  ordinary  vigour  ;  and  I  entertain  scarcely 
any  doubt  that  the  same  roots  which  afforded  flowers  in  the  present 
season,  will  blossom  strongly  in  the  next.  It  appears  therefore  from  this, 
and  the  two  preceding  experiments,  that  the  same  degree  of  temperature, 
which  may  promote  the  growth,  and  exuberant  health  of  the  plant,  may, 
at  the  same  time,  render  it  wholly  unproductive  of  fruit  or  offspring. 

The  Fig  Tree.  Several  varieties  of  this  species  were  subjected  to 
experiment ;  but  the  trees,  although  planted  in  pots,  grew  with  so  much 
luxuriance,  and  afforded  me  so  little  prospect  of  fruit,  that  I  removed  all 
except  those  of  the  large  white  variety,  from  the  house.  The  white  fig- 
tree  succeeded  perfectly,  first  ripening  its  spring-figs,  (those  which  usually 
ripen  in  the  open  air  in  this  country,)  and  afterwards  its  summer  figs. 
The  trees  then  produced  new  leaves  and  branches  :  and  the  fruit,  which 
would  have  appeared  in  the  next  spring,  ripened  in  high  perfection  in 
September.  Subsequently  also  a  few  of  those,  which,  in  the  ordinary 
course  of  the  growth  of  the  tree,  would  have  appeared  as  the  summer 
crop  of  next  year,  have  ripened,  and  these,  though  far  inferior  to  those 
of  the  preceding  crops,  have  not  been  without  merit. 

The  Nectarine.  A  seed  of  this  species  of  fruit  was  planted  in  a  hot- 
bed, in  January  last,  and  it  vegetated  in  the  succeeding  month.  It  was 
subsequently  removed  to  the  hot-house,  in  which  it  continued  to  grow 
through  the  summer,  without  being  in  the  smallest  degree  drawn  by  the 
high  temperature  in  which  it  was  placed  :  its  wood,  on  the  contrary,  is 
remarkably  short-jointed,  and  is  covered  with  blossom-buds  ;  from  which 
I  think  it  will  be  practicable  to  obtain  ripe  fruit,  within  sixteen  months 
of  the  period,  at  which  the  plant  first  sprang  from  the  ground. 

The  Orange  and  Lemon.  A  very  high  temperature  appeared  peculiarly 
favourable  to  plants  of  these  species,  or,  I  believe,  more  properly  of  this 
species  ;  for  I  consider  both,  with  the  citron  and  shaddock,  to  be  varieties 
only  of  the  lime.  A  plant  which  sprang  from  seed  in  March,  had,  in  the 
end  of  August,  attained  the  height  of  more  than  four  feet,  with  pro- 
portionate strength ;  when  wanting  the  place  it  occupied  for  another 
purpose,  it  was  removed  from  the  house.  I  obtained  in  April  a  plant  of 
the  China  orange,  with  one  very  small  fruit  upon  it,  which  has  ripened 


240  ON    THE    EFFECTS    OF    HIGH    TEMPERATURE    OX    SOME    PLANTS. 

in  much  apparent  perfection,  and  the  tree  exhibits  every  appearance  of 
the  most  exuberant  health. 

The  Mango.  (Mangifera  Indica.)  This  species  of  fruit-tree  appears 
to  possess  great  peculiarity  of  constitution ;  for,  although  a  native  of  a 
very  hot  and  bright  climate,  and  capable  of  bearing,  with  apparent 
benefit,  the  hot  drying  winds  of  Bengal,  it  vegetates  freely,  and  retains 
its  health  in  comparatively  low  temperature,  and  under  a  cloudy 
atmosphere.  The  plants  I  possess  sprang  from  seeds  in  October  1818; 
and  the  leaves  acquired,  during  winter,  their  proper  dark  colour,  and 
remained  in  perfect  health  till  spring ;  although,  not  possessing  at  that 
period,  a  hot-house,  I  was  very  ill  prepared  to  preserve  them.  Tn  March 
they  began  to  shoot  a  second  time,  without  having  been,  I  believe,  at 
any  period  subjected  to  a  higher  temperature  than  60°,  and  some  of  them 
are  now  shooting  strongly ;  although  the  temperature  of  my  house  during 
the  last  five  weeks,  except  once  or  twice  in  very  bright  days,  has  rarely 
been  so  high  as  60°.  The  mode  of  growth  of  this  plant  appears  also  to 
be  very  singular ;  it  extends'  a  few  inches,  and  then  closes  its  terminal 
buds,  as  if  its  growth  for  the  season  were  ended.  One  of  my  plants  has 
done  so  nine  times  within  the  last  thirteen  months,  without  having 
acquired  a  greater  height  than  two  feet  seven  inches.  I  am  much 
inclined  to  believe  that  the  mango  might  be  raised  in  great  abundance 
and  considerable  perfection  in  the  stove  in  this  country,  for  it  is  a  fruit 
which  acquires  maturity  within  a  short  period.  It  blossoms,  in  Bengal, 
in  January,  and  ripens  in  the  end  of  May;  and  Mr.  Turner,  in  his 
journey  to  Thibet,  states  that  he  found  the  mango  growing  in  latitude 
27°  50'  in  Bout  an,  in  the  same  orchard  with  the  apple-tree ;  the  apples 
ripening  in  July,  and  the  mangoes  in  September.  And  another  Eastern 
traveller  of  credit  (I  think  it  is  Mr.  Barrow),  mentions  an  instance  in 
which  a  frost,  sufficiently  severe  to  have  injured  the  crops  of  barley,  had 
proved  fatal  to  the  blossoms  (only)  of  the  mango-trees. 

The  Alligator,  or  Avocado  pear.  (Laurus  Persea.)  The  plants  of  this 
species  have  grown  with  rather  troublesome  luxuriance  in  my  house, 
though  they  have  been  generally  confined  to  small  pots ;  one  plant  to 
which  a  larger  pot  was  given  is  more  than  six  feet  high,  with  branches 
extending  five  feet  wide  ;  and  a  stem,  the  growth  of  a  single  year, 
exceeding,  at  its  base,  an  inch  in  diameter.  To  obtain  fruit  of  this 
species  within  the  narrow  limits  of  a  forcing-house,  it  would  be  necessary 
to  propagate  from  buds  or  grafts  taken  from  the  extreme  branches  of 
trees  of  considerable  age. 

The    Mammce-tree.      (Mammea    Americana.)      Very  contrary  to   my 


ON    THE    EFFECTS    OF    HIGH    TEMPERATURE    ON    SOME    PLANTS.  241 

expectations,  this  plant,  a  native  of  Jamaica,  proved  extremely  impatient 
of  heat  and  light,  and  its  young  leaves  always  required  to  be  shaded  when 
the  temperature  of  the  house  exceeded  90°.  But  with  proper  attention 
to  screen  the  leaves  from  the  mid-day  sun,  till  they  acquired  maturity, 
the  young  trees  of  this  species  have  succeeded  as  well  as  those  of  any  of 
the  preceding  species. 

Several  other  plants,  part  of  them  natives  of  temperate  climates,  grew 
in  my  house  through  the  whole  summer,  without  any  one  of  them  being 
drawn,  or  any  way  injured,  by  the  very  high  temperature  to  which  they 
were  occasionally  subjected ;  and  from  these,  and  other  facts,  which  have 
come  within  my  observation,  I  think  myself  justified  in  inferring,  that,  in 
almost  all  cases  in  which  the  object  of  the  cultivator  is  to  promote  the 
rapid  and  vigorous  growth  of  his  plants,  a  very  high  temperature,  provided 
it  be  accompanied  by  bright  sunshine,  may  be  employed  with  great 
advantage ;  but  it  is  necessary  that  the  glass  of  his  house  should  be  of 
good  quality,  and  that  his  plants  be  placed  near  it,  and  be  abundantly 
supplied  with  food  and  water.  In  the  preceding  experiments,  water 
was  made  the  vehicle  of  food  to  the  roots  of  the  plants,  in  the  manner 
I  have  described  in  a  former  communication  *,  and  with  similar  good 
effects. 

My  house  contains  a  few  pine- apple  plants,  in  the  treatment  of  which 
I  have  deviated  somewhat  widely  from  the  common  practice ;  and,  I 
think,  with  the  best  effects  ;  for  their  growth  has  been  exceedingly  rapid, 
and  a  great  many  gardeners,  who  have  come  to  see  them,  have  unani- 
mously pronounced  them  more  perfect  than  any  which  they  had  previously 
seen.  But  many  of  the  gardeners  think  that  my  mode  of  management 
will  not  succeed  in  winter,  and  that  my  plants  will  become  unhealthy,  if 
they  do  not  perish,  in  that  season ;  and  as  some  of  them  have  had  much 
experience,  and  I  very  little,  I  wish  at  present  to  decline  saying  more 
relative  to  the  culture  of  that  plant. 

*  See  above,  page  211. 


242 


XL.— UPON   THE     CULTURE     OF    THE    PINE-APPLE,    WITHOUT   BARK,   OR 

OTHER    HOT-BED. 

[Read  before  the  HORTICULTURAL  SOCIETY,  March  7th,  1820.] 

IN  a  communication  which  I  had  the  honour  to  send  to  the  Horticul- 
tural Society  in  the  last  autumn,  upon  the  effects  of  very  high  temperature, 
when  accompanied  by  very  bright  sunshine,  upon  some  species  of  plants, 
I  mentioned  that  I  had  made  a  few,  apparently  very  successful,  experiments 
upon  the  culture  of  the  pine-apple :  but  I  declined,  at  that  period,  to  describe 
the  means  I  had  used;  because  several  experienced  gardeners  in  the  vicinity 
were  of  opinion  that  my  plants  could  not  be  made  to  survive,  in  health 
at  least,  the  winter.  The  same  gardeners  have  since  frequently  visited 
my  hothouse,  and  they  have  unanimously  pronounced  my  plants  more 
healthy  and  vigorous  than  any  they  had  previously  seen  :  and  they  are  all,  I 
have  good  reason  to  believe,  zealous  converts  to  my  mode  of  culture. 

I  had  no  intention  whatever  to  attempt  to  raise  pine-apples  till  the 
autumn  of  1818,  when  I  received  from  one  of  my  friends  in  this  vicinity, 
Mr.  Ricketts,  of  Ashford  Hall,  some  seeds  of  the  mango,  and  soon  after- 
wards some  more  seeds  of  that,  and  other  tropical  fruit-trees,  from  one 
of  our  members,  Mr.  Pallmer.  I  then  resolved  to  erect  a  hothouse, 
chiefly  for  the  purpose  of  attempting  to  cultivate  the  mango  ;  but  I  had 
long  been  much  dissatisfied  with  the  manner  in  which  the  pine-apple  plant 
is  usually  treated,  and  very  much  disposed  to  believe  the  bark  bed,  as  Mr. 
Kent  has  stated  it  in  our  Transactions*,  "  worse  than  useless,"  subse- 
quently to  the  emission  of  roots  by  the  crowns  or  suckers.  I  therefore 
resolved  to  make  a  few  experiments  upon  the  culture  of  that  plant ;  but 
as  I  had  not  at  that  period,  the  beginning  of  October,  any  hothouse,  I 
deferred  obtaining  plants  till  the  following  spring.  My  hothouse  was 
not  completed  till  the  second  week  in  June,  at  which  period  I  began  my 
experiment  upon  nine  plants,  which  had  been  but  very  ill  preserved 
through  the  preceding  winter  by  the  gardener  of  one  of  my  friends,  with 
very  inadequate  means,  and  in  a  very  inhospitable  climate.  These,  at 
this  period,  were  not  larger  plants  than  some  which  I  have  subsequently 
raised  from  small  crowns,  (three  having  been  afforded  by  one  fruit,) 
planted  in  the  middle  of  August,  were  in  the  end  of  December  last ;  but 
they  are  now  beginning  to  blossom,  and,  in  the  opinion  of  every  gardener 
who  has  seen  them,  promise  fruit  of  great  size  and  perfection.  They  are 
all  of  the  variety  known  by  the  name  of  Ripley's  Queen  Pine. 

Upon  the  introduction  of  my  plants  into  the  hothouse,  the  mode  of 
management,   which  it  is  the  object  of  the  present  communication  to 

*  Horticultural  Transactions,  Vol.  III.  page  288. 


ON    THE    CULTURE    OF    THE    PINE-APPLE.  243 

describe,  commenced.     They  were  put  into  pots  of  somewhat  more  than 
a  foot  in  diameter,  in  a  compost  made  of  thin  green  turf,  recently  taken 
from  a  river  side,  chopped  very  small,  and  pressed  closely,  whilst  wet, 
into  the  pots ;  a  circular  piece  of  the  same  material,  of  about  an  inch  in 
thickness,  having  been  inverted,  unbroken,  to  occupy  the  bottom  of  each 
pot.     This  substance,  so  applied,  I  have  always  found  to  afford  the  most 
efficient  means  for  draining  off  superfluous  water,  and  subsequently  of 
facilitating  the  removal  of  a  plant  from  one  pot  to  another,  without  loss 
of  roots.     The  surface  of  the  reduced  turf  was  covered  with  a  layer  of 
vegetable  mould  obtained  from  decayed  leaves,  and  of  sandy  loam,  to  pre- 
vent the  growth  of  the  grass  roots.  The  pots  were  then  placed  to  stand  upon 
brick  piers,  near  the  glass ;  and  the  piers  being  formed  of  loose  bricks  (with- 
out mortar),  were  capable  of  being  reduced  as  the  height  of  the  plants 
increased.  The  temperature  of  the  house  was  generally  raised  in  hot  and 
bright  days,  chiefly  by  confined  solar  heat,  from  95°  to  105°,  and  sometimes 
to  110°,  no  air  being  ever  given  till  the  temperature  of  the  house  exceeded 
95°;  and  the  escape  of  heated  air  was  then,  only  in  a  slight  degree,  permitted. 
In  the  night  the  temperature  of  the  house  generally  sunk  to  70°,  or  some- 
what lower.    At  this  period,  and  through  the  months  of  July  and  August, 
a  sufficient  quantity  of  pigeon's  dung  was  steeped  in  the  water,  which  was 
given  to  the  pine-plants,  to  raise  its  colour  nearly  to  that  of  porter,  and 
with  this  they  were  usually  supplied  twice  a  day  in  very  hot  weather ;  the 
mould  in  the  pots  being  kept  constantly  very  damp,  or  what  gardeners 
would  generally  call  wet.    In  the  evenings,  after  very  hot  days,  the  plants 
were  often  sprinkled  with  clear  water,  of  the  temperature  of  the  external 
air;  but  this  was  never  repeated  till  all  the  remains  of  the  last  sprinkling 
had  disappeared  from  the  axillae  of  the  leaves. 

It  is,  I  believe,  almost  a  general  custom  with  gardeners,  to  give  their 
pine-plants  larger  pots  in  autumn,  and  this  mode  of  practice  is  approved 
by  Mr.  Baldwin*.  I  nevertheless  cannot  avoid  thinking  it  wrong ;  for 
the  plants,  at  this  period,  and  subsequently,  owing  to  want  of  light,  can 
generate  a  small  quantity  only  of  new  sap  ;  and  consequently,  the  matter 
which  composes  the  new  roots,  that  the  plant  will  be  excited  to  emit  into 
the  fresh  mould,  must  be  drawn  chiefly  from  the  same  reservoir,  which  is 
to  supply  the  blossom  and  fruit :  and  I  have  found  that  transplanting 
fruit-trees,  in  autumn,  into  larger  pots,  has  rendered  their  next  year's 
produce  of  fruit  smaller  in  size,  and  later  in  maturity.  I  therefore  would 
not  remove  my  pine-plants  into  larger  pots,  although  those  in  which  they 
grow  are  considerably  too  small. 

*  Baldwin's  Practical  Directions  for  the  Culture  of  the  Ananas,  page  16. 

R2 


244  ON    THE    CULTURE    OP    THE    PINE-APPLE. 

As  the  length  of  the  days  diminished,  and  the  plants  received  less 
light,  their  ability  to  digest  food  diminished.  Less  food  was  in  conse- 
quence dissolved  in  the  water,  which  was  also  given  with  a  more  sparing 
hand  ;  and  as  winter  approached,  water  only  was  given,  and  in  small 
quantities. 

During  the  months  of  November  and  December,  the  temperature  of 
the  house  was  generally  little  above  50°,  and  sometimes  as  low  as  48°  *. 
Most  gardeners  would,  I  believe,  have  been  alarmed  for  the  safety  of  their 
plants  at  this  temperature  ;  but  the  pine  is  a  much  hardier  plant  than  it 
is  usually  supposed  to  be ;  and  I  exposed  one  young  plant  in  December 
to  a  temperature  of  32°,  by  which  it  did  not  appear  to  sustain  any  injury. 
I  have  also  been  subsequently  informed  by  one  of  my  friends,  Sir  Harford 
Jones,  who  has  had  most  ample  opportunities  of  observing,  that  he  has 
frequently  seen,  in  the  East,  the  pine-apple  growing  in  the  open  air,  where 
the  surface  of  the  ground,  early  in  the  mornings,  showed  unequivocal 
marks  of  a  slight  degree  of  frost. 

My  plants  remained  nearly  torpid,  and  without  growth,  during  the 
latter  part  of  November,  and  in  the  whole  of  December ;  but  they  began 
to  grow  early  in  January,  although  the  temperature  of  the  house  rarely 
reached  60° ;  and  about  the  20th  of  that  month,  the  blossom,  or  rather 
the  future  fruit,  of  the  earliest  plant  became  visible ;  and  subsequently 
to  that  period  their  growth  has  appeared  very  extraordinary  to  gardeners 
who  had  never  seen  pine-plants  growing,  except  in  a  bark-bed  or  other 
hotbed.  I  believe  this  rapidity  of  growth,  in  rather  low  temperature, 
may  be  traced  to  the  more  excitable  state  of  their  roots,  owing  to  their 
having  passed  the  winter  in  a  very  low  temperature  comparatively  with 
that  of  a  bark-bed.  The  plants  are  now  supplied  with  water  in  moderate 
quantities,  and  holding  in  solution  a  less  quantity  of  food  than  was  given 
them  in  summer. 

In  planting  suckers,  I  have,  in  several  instances,  left  the  stems  and 
roots  of  the  old  plant  remaining  attached  to  them ;  and  these  have  made 
a  much  more  rapid  progress  than  others.  One  strong  sucker  was  thus 
planted  in  a  large  pot  upon  the  20th  of  July ;  and  that  is  beginning  to 
show  fruit.  Its  stem  is  thick  enough  to  produce  a  very  large  fruit ;  but 
its  leaves  are  short,  though  broad  and  numerous ;  and  the  gardeners, 
who  have  seen  it,  all  appear  wholly  at  a  loss  to  conjecture  what  will  be  the 
value  of  its  produce.  In  other  cases,  in  which  I  retained  the  old  stems 
and  roots,  I  selected  small  and  late  suckers,  and  these  have  afforded  me 
the  most  perfect  plants  I  have  ever  seen  ;  and  they  do  not  exhibit  any 

*  Subsequently  to  the  time  this  paper  was  sent  to  the  Society,  I  have  been  informed,  that 
the  thermometer  was  once,  in  the  last  winter,  so  low  as  40  degrees. 


ON    THE    CULTURE    OF    THE    PINE-APPLE.  245 

symptoms  of  disposition  to  fruit  prematurely.  I  am,  however,  still 
ignorant  whether  any  advantage  will  be  ultimately  obtained  by  this  mode 
of  treating  the  queen-pine,  but  I  believe  it  will  be  found  applicable  with 
much  advantage  in  the  culture  of  those  varieties  of  the  pine  which  do 
not  usually  bear  fruit  till  the  plants  are  three  or  four  years  old. 

I  shall  now  offer  a  few  remarks  upon  the  facility  of  managing  pines  in 
the  manner  recommended,  and  upon  the  necessary  amount  of  the  expense. 
My  gardener  is  an  extremely  simple  labourer,  he  does  not  know  a  letter 
or  a  figure ;  and  he  never  saw  a  pine-plant  growing,  till  he  saw  those  of 
which  he  has  the  care.  If  I  were  absent,  he  would  not  know  at  what 
period  of  maturity  to  cut  the  fruit ;  but  in  every  other  respect  he  knows 
how  to  manage  the  plants  as  well  as  I  do ;  and  I  could  teach  any  other 
moderately  intelligent  and  attentive  labourer,  in  one  month,  to  manage 
them  just  as  well  as  he  can  :  in  short,  I  do  not  think  the  skill  necessary 
to  raise  a  pine-apple,  according  to  the  mode  of  culture  I  recommend,  is  as 
great  as  that  requisite  to  raise  a  forced  crop  of  potatoes.  The  expense 
of  fuel  for  my  hothouse,  which  is  forty  feet  long  by  twelve  wide,  is 
rather  less  than  seven-pence  a  day  here,  where  I  am  twelve  miles  distant 
from  coal-pits ;  and  if  I  possessed  the  advantages  of  a  curved  iron  roof, 
such  as  those  erected  by  Mr.  Loudon,  at  Bayswater,  which  would  prevent 
the  too  rapid  escape  of  heated  air  in  cold  weather,  I  entertain  no  doubt, 
that  the  expense  of  heating  a  house  forty-five  feet  long  and  ten  wide,  and 
capable  of  holding  eighty  fruiting  pine-plants,  exclusive  of  grapes  or  other 
fruits  upon  the  back  wall,  would  not  exceed  four-pence  a  day.  A  roof, 
of  properly  curved  iron  bars,  appears  to  me  also  to  present  many  other 
advantages  :  it  may  be  erected  at  much  less  cost,  it  is  much  more  durable, 
it  requires  much  less  expense  to  paint  it,  and  it  admits  greatly  more  light. 

I  have  not  yet  been  troubled  with  insects  upon  my  pine-plants,  and 
have  not,  of  course,  tried  any  of  the  published  receipts  for  destroying 
them.  Mr.  Baldwin  recommends  the  steam  of  hot  fermenting  horse- 
dung*  :  I  conclude  the  destructive  agent,  in  this  case,  is  ammoniacal  gas ; 
which  Sir  Humphrey  Davy  informed  me  he  had  found  to  be  instantly 
fatal  to  every  species  of  insect ;  and  if  so,  this  might  be  obtained  at  a 
small  expense,  by  pouring  a  solution  of  crude  muriate  of  ammonia  upon 
quicklime ;  the  stable  or  cow-house  would  afford  an  equally  efficient, 
though  less  delicate  fluid.  The  ammoniacal  gas  might,  I  conceive,  be 
impelled,  by  means  of  a  pair  of  bellows,  amongst  the  leaves  of  the  infected 
plants,  in  sufficient  quantity  to  destroy  animal,  without  injuring  vegetable 
life :  and  it  is  a  very  interesting  question  to  the  gardener,  whether  his 
hardy  enemy,  the  red  spider,  will  bear  it  with  impunity. 

*  Baldwin's  Practical  Directions,  &c.  page  30. 


246 


XLI.— PHYSIOLOGICAL  OBSERVATIONS  UPON  THE  EFFECTS  OF  PAR- 
TIAL DECORTICATION,  OR  RINGING  THE  STEMS  OR  BRANCHES,  OF 
FRUIT-TREES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  June  6th,  1820.] 

IT  has  not,  I  think,  been  sufficiently  explained  by  what  means  the 
obstruction,  or  prevention,  of  the  passage  of  the  fluids  of  trees  through 
their  bark  operates  in  occasioning  an  increased  production  of  blossom, 
and  a  more  rapid  growth,  and  more  early  maturity,  of  the  fruit :  the 
gardener  is  in  consequence,  in  many  cases,  unable  to  foresee  whether  he 
is  likely  to  obtain  benefit,  or  to  sustain  injury,  from  the  operation  ;  and 
he  is  wholly  without  the  means  of  knowing  how  to  adopt  his  mode  of 
operating,  with  any  degree  of  precision,  to  the  object  which  he  has  in 
view.  I  therefore  address  the  following  observations  under  the  impression 
that  the  hypothesis  which  I  have  advanced  in  different  papers  in  the 
Philosophical  Transactions  will  afford  a  satisfactory  explanation  of  the 
cause  of  all  the  above-mentioned  effects. 

According  to  that  hypothesis,  the  true  sap  of  trees  is  wholly  generated 
in  their  leaves,  from  which  it  descends  through  their  bark  to  the 
extremities  of  their  roots,  depositing  in  its  course  the  matter  which  is 
successively  added  to  the  tree ;  whilst  whatever  portion  of  such  sap  is  not 
thus  expended  sinks  into  the  alburnum,  and  joins  the  ascending  current, 
to  which  it  communicates  powers  not  possessed  by  the  recently-absorbed 
fluid.  When  the  course  of  the  descending  current  is  intercepted,  that 
necessarily  stagnates,  and  accumulates  above  the  decorticated  space ; 
whence  it  is  repulsed,  and  carried  upwards,  to  be  expended  in  an 
increased  production  of  blossoms  and  of  fruit  ;  and,  consistently  with 
these  conclusions,  I  have  found  that  part  of  the  alburnum  which  is 
situated  above  the  decorticated  space  to  exceed  in  specific  gravity,  very 
considerably,  that  which  lies  below  it.  The  repulsion  of  the  descending 
fluid  therefore  accounts,  I  conceive^  satisfactorily  for  the  increased 
produce  of  blossoms,  and  more  rapid  growth  of  the  fruit,  upon  the 
decorticated  branch  ;  but  there  are  other  causes  which  operate  in 
promoting  its  more  early  maturity.  The  part  of  the  branch  which  is 
below  the  decorticated  space  is  ill  supplied  with  nutriment,  and  ceases 
almost  to  grow :  it  in  consequence  operates  less  actively  in  impelling  the 
ascending  current  of  sap,  which  must  also  be  impeded  in  its  progress 
through  the  decorticated  space.  The  parts  which  are  above  it  must 
therefore  be  less  abundantly  supplied  with  moisture ;  and  drought,  in 
such  cases,  always  operates  very  powerfully  in  accelerating  maturity. 


ON    RINGING    THE    STEMS    OR    BRANCHES    OF    FRUIT-TREES.  247 

When  the  branch  is  small,  or  the  space  from  which  the  bark  has  been 
taken  off  is  considerable,  it  almost  always  operates  in  excess ;  a  morbid 
state  of  early  maturity  is  induced,  and  the  fruit  is  worthless. 

If  this  view  of  the  effects  of  partial  decortication,  or  ringing,  be  a  just 
one,  it  follows  that  much  of  the  success  of  the  operation  must  be 
dependent  upon  the  selection  of  proper  seasons,  and  upon  the  mode  of 
performing  it  being  well  adapted  to  the  object  of  the  operator.  If  that 
be  the  production  of  blossoms,  or  the  means  of  making  the  blossoms  set 
more  freely,  the  ring  of  bark  should  be  taken  off  early  in  the  summer, 
preceding  the  period  at  which  blossoms  are  required ;  but  if  the  enlarge- 
ment and  more  early  maturity  of  the  fruit  be  the  object,  the  operation 
should  be  delayed  till  the  bark  will  readily  part  from  the  alburnum  in 
the  spring.  The  breadth  of  the  decorticated  space,  as  Mr.  Sabine  has 
justly  observed,  must  be  adapted  to  the  size  of  the  branch  *  ;  but  I  have 
never  witnessed  any  except  injurious  effects  whenever  the  experiment 
has  been  made  upon  very  small  or  very  young  branches ;  for  such  become 
debilitated  and  sickly  long  before  the  fruit  can  acquire  a  proper  state  of 
maturity.  I  have  found  a  tight  ligature,  applied  in  the  preceding 
summer,  in  such  cases,  to  answer,  in  a  great  measure,  all  the  purposes  of 
ringing,  with  far  less  injurious  consequences  to  the  tree  ;  and  if  such  were 
applied  to  the  stems  or  principal  branches  of  cherry-trees  which  are  to 
be  forced  very  early  in  the  following  year,  I  believe  the  blossoms  would 
be  found  to  set  more  freely,  and  the  fruit  to  attain  an  early  maturity.  I 
have  also  succeeded  in  preserving,  to  a  great  extent,  the  health  of  a 
ringed  branch  by  instantly  covering  the  exposed  surface  of  the  alburnum 
with  a  tight  bandage  of  coarse  thread  coated  with  bees- wax,  if  the  branch 
were  small ;  or  of  fine  packthread,  if  it  were  large ;  so  as  wholly  to  fill 
the  space  from  which  the  bark  had  been  taken.  By  such  means  the 
desiccation  and  consequent  death  of  the  external  surface  of  the  alburnum 
have  been  prevented ;  and  I  consequently  think  it  not  improbable  that 
the  operation  might  be  performed  with  advantage  upon  the  cherry-tree, 
and  some  other  fruit-trees,  to  which  it  has  hitherto  been  found  destruc- 
tive. I  have  tried,  with  the  most  ample  success,  in  the  present  spring, 
the  application  of  such  a  bandage  upon  a  ringed  branch  of  a  fig-tree ; 
and  the  evidence  I  have  obtained  of  its  mode  of  operation  has  not  been 
confined  to  a  recent  period,  for  I  applied  such  a  bandage  in  the  first 
experiment  I  ever  made  upon  a  plant,  and  at  the  distance  (I  have 
particular  reasons  for  knowing)  of  precisely  half  a  century  from  the 
present  time ; — when  I  was  a  school-boy  of  ten  years  old. 

*   See  Horticultural  Transactions,  Volume  IV.  page  124. 


248  ON    RINGING    THE    STEMS    OR    BRANCHES    OF    FRUIT-TREES. 

I  am  not  friendly  to  the  process  of  ringing,  in  whatever  manner  it  may 
be  performed ;  and  I  think  it  never  should  be  adopted  unless  in  cases 
where  blossoms  cannot  be  otherwise  obtained,  or  where,  in  very  early 
forcing,  the  value  of  a  single  crop  of  fruit  exceeds  the  value  of  the  tree. 
For  it  is  a  process  which  promotes  the  expenditure,  whilst  it  diminishes 
the  creation,  of  the  vital  fluid  of  the  tree,  which  must  also  suffer  in  all 
subsequent  periods,  from  the  organic  injuries  it  sustains. 


XLII.— UPON   THE    CULTURE    OF  THE    FIG-TREE,    IN   THE   STOVE. 
[Read  before  the  HORTICULTURAL  SOCIETY,  July  18th,  1820.] 

IN  a  communication  respecting  the  effects  of  very  high  temperature 
upon  certain  species  of  plants,  which  was  addressed  by  me  to  the  Horti- 
cultural Society  in  the  last  autumn*,  I  stated  that  fig-trees  of  one  variety 
had  afforded  four  successive  crops  in  the  same  season.  The  fourth  crop, 
at  that  period,  was  only  beginning  to  ripen,  and  I  thought  the  fruit 
somewhat  inferior  in  quality  to  that  which  had  ripened  early  in  the 
season ;  but  the  subsequent  portion  of  it  proved  most  excellent ;  and  some 
figs,  which  were  gathered  upon  Christmas-day,  were  thought  by  myself, 
and  a  friend  who  was  with  me,  much  the  best  we  had  ever  tasted.  The 
same  plants  have  since  ripened  four  more  crops,  being  eight  within  twelve 
months ;  and  upon  a  ringed  branch  of  one  year  old,  and  about  an  inch 
in  diameter,  a  ninth  crop,  consisting  of  sixty  figs,  will  ripen  within  the 
next  month.  I  possess  only  two  plants,  each  growing  in  a  pot,  which 
contains  something  less  than  fourteen  square  inches  of  mould,  and 
occupying  together  a  space  equal  to  about  sixty-four  square  feet  of  the 
back  wall  of  my  pine-stove ;  from  which  space  the  number  of  figs  that 
have  been  gathered  within  twelve  months  has  been  little,  if  any,  less  than 
three  hundred :  and  I  see  every  prospect  of  a  succession  of  crops  till 
winter.  1  therefore  send  the  following  account  of  the  mode  of  culture 
which  has  been  employed,  in  the  hope  that  it  may  prove  useful  to  those 
who  are  sufficiently  admirers  of  the  fig  to  think  it  deserving  a  place  in 
the  forcing-house. 

My  trees  grow,  as  I  have  stated  in  the  communication  to  which  I  have 
above  alluded,  in  exceedingly  rich  mould,  and  are  most  abundantly 
supplied  with  water  which  holds  much  manure  in  solution.  They 
consequently  shoot  with  great  vigour,  notwithstanding  the  small  space 

*  See  above,  page  239. 


UPON  THE  CULTURE  OF  THE  FIG-TREE,  IN  THE  STOVE.         249 

to  which  their  roots'  are  confined ;  and  they  require  some  attention  to 
restrain  them  within  the  limits  assigned  to  them  ;  but  I  have  found  the 
following  mode  of  treatment  perfectly  efficient  and  successful. 

Whenever  a  branch  appears  to  be  extending  with  too  much  luxuriance, 
its  point,  at  the  tenth  or  twelfth  leaf,  is  pressed  between  the  finger  and 
thumb,  without  letting  the  nails  come  in  contact  with  the  bark,  till  the 
soft  succulent  substance  is  felt  to  yield  to  the  pressure.  Such  branch  in 
consequence  ceases  subsequently  to  elongate  ;  and  the  sap  is  repulsed  to 
be  expended  where  it  is  more  wanted.  A  fruit  ripens  at  the  base  of  each 
leaf,  and  during  the  period  in  which  the  fruit  is  ripening,  one  or  more  of 
the  lateral  buds  shoots,  and  is  subsequently  subjected  to  the  same  treat- 
ment, with  the  same  result.  When  I  have  suffered  such  shoots  to  extend 
freely  to  their  natural  length,  I  have  found  that  a  small  part  of  them 
only  became  productive  either  in  the  same  or  the  ensuing  season,  though 
I  have  seen  that  their  buds  obviously  contained  blossoms.  I  made 
several  experiments  to  obtain  fruit  in  the  following  spring  from  other 
parts  of  such  branches,  which  were  not  successful ;  but  I  ultimately 
found  that  bending  such  branches,  as  far  as  could  be  done  without  danger 
of  breaking  them,  rendered  them  extremely  fruitful ;  and  in  the  present 
spring  thirteen  figs  ripened  perfectly  upon  a  branch  of  this  kind  within 
the  space  of  ten  inches.  In  training,  the  ends  of  all  the  shoots  have 
been  made,  as  far  as  practicable,  to  point  downwards. 

When  I  made  my  former  communication  upon  this  subject,  I  supposed 
that  the  variety  which  had  succeeded  so  well  in  my  hothouse  was  the 
large  white  fig,  the  cuttings  from  which  I  raised   my  plants   having 
been  sent  to  me  as  such ;  and  that  its  size  had  been  somewhat  diminished 
by  the  confinement  of  the  roots  to  pots,  and  the  exuberant  produce  of 
fruit.     I  have,  however,  recently  seen  a  private  letter  of  the  late  Mr. 
Speechley's  (the  well-known  author  of  Treatises  on  the  Culture  of  the 
Pine-Apple  and  Vine),  in  which  he  speaks  of  a  white  fig  that  he  had 
found  to  succeed  perfectly  in  high  temperature,  but  the  name  of  which 
he  does  not  appear  to  have  known ;  and  I  believe  that  which  I  am  culti- 
vating to  be  the  one  he  has  described.     The  form  of  the  fruit,  in  its  most 
perfect  state,  is  an  oblate  spheroid  of  nearly  two  inches  in  width  ;  but  its 
length  often  exceeds  its  breadth,  and  it  then  tapers  to  the  point  next  the 
stalk. 


250 

XLIIL— ON  THE   CULTIVATION  OF  THE  COCKSCOMB. 
[Read  before  the  HORTICULTURAL  SOCIETY,  Dec.  19,  1820.] 

THE  flower  of  the  cockscomb,  which  I  sent  to  the  meeting  of  the  Society 
on  the  17th  of  October,  may  be  considered  a  fair  sample  of  all  that  I  grew 
this  year ;  two  of  six  having  been  larger,  and  two  somewhat  smaller  *. 

In  cultivating  these  plants,  I  have  treated  them  precisely  as  I  do  my 
pine-apple  plants,  having  in  some  respects  a  similar  object  in  view ;  for  in 
both  a  single  fruit-stalk  of  great  strength  is  requisite,  the  protrusion  of 
which  should  be  retarded  as  long  as  possible,  consistently  with  the  rapid 
growth  of  the  plant.  The  compost  I  employed  was  the  most  nutritive 
and  stimulating  that  I  could  apply,  consisting  of  one  part  of  unfermented 
horse-dung  fresh  from  the  stable  and  without  litter,  one  part  of  burnt 
turf,  one  part  of  decayed  leaves,  and  two  parts  of  green  turf,  the  latter 
being  in  lumps  of  about  an  inch  in  diameter,  to  keep  the  mass  so  hollow 
that  the  water  might  have  free  liberty  to  escape,  and  the  air  to  enter. 
Manure  was  also  given  in  a  liquid  state  by  steeping  pigeon-dung  in  the 
water,  which  was  given  very  freely.  The  plants  were  put,  whilst  very 
small,  into  pots  of  four  inches  diameter,  and  three  inches  deep  ;  as  soon 
as  their  roots  had  reached  the  sides  of  the  pots,  and  before  they  had 
become  in  any  degree  matted,  they  were  transplanted  into  pots  of  a  foot 
in  diameter,  and  about  nine  inches  deep.  Particular  attention  was 
paid  to  the  state  of  the  roots,  for  I  have  reason  to  think  that  the  com- 
pression of  them  in  the  pot  has,  under  all  circumstances,  a  tendency  to 
accelerate  the  flowering  of  plants. 

Under  this  mode  of  treatment,  the  plants  became  large  and  strong 
before  they  showed  a  disposition  to  blossom ;  they  usually  divide  into 
many  branches  (as  the  pine-apple  plant  will  also  do),  which  will 
greatly  injure  them,  if  due  attention  be  not  paid  to  remove  the  side 
branches  when  very  young.  My  plants  were  at  all  times  so  placed  that 
their  leaves  reached  within  a  few  inches  of  the  glass,  and  they  were  sub- 
jected to  the  same  heat  (from  70e  to  100°),  during  the  summer,  as  my 
pine-apple  plants. 

The  seeds  of  the  plants  which  I  raised  in  the  present  season  were  not 
sown  till  too  late  in  the  spring ;  and  if  I  were  to  repeat  the  experiment, 
I  entertain  no  doubt  of  producing  much  larger  flowers  than  the  one  I  sent 
you  ;  for  the  variety,  I  believe,  is  of  superior  excellence.  It  affords  seeds 
very  sparingly,  as  you  would  perceive  by  the  specimen  sent. 

*  The  flower  sent  by  Mr.  Knight  measured  eighteen  inches  in  width  and  seven  inches  in 
height  from  the  top  of  the  stalk  ;  it  was  thick  and  full,  and  of  a  most  intense  colour.  A  very 
accurate  drawing  of  it  has  been  executed  by  Mrs.  Pope,  and  placed  in  the  library  of  the  Society. 
(Note  by  Mr.  Sabine.) 


251 


XLIV.— OBSERVATIONS    ON    HYBRIDS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  6,  1821.] 

MUCH  difference  of  opinion  appears  to  exist  between  my  friend  the 
Hon.  William  Herbert  and  myself,  relatively  to  the  production  of  hybrid 
plants ;  he  supposing  that  many  originally  distinct  species  are  capable  of 
breeding  together,  without  producing  mules  (that  is,  without  producing 
plants  incapable  of  affording  offspring)  ;  and  I  considering  the  fact  of  two 
supposed  species  having  bred  together,  without  producing  mules,  to  be 
evidence  of  the  original  specific  identity  of  the  two.  Our  difference  of 
opinion  is,  however,  I  believe,  apparently  much  greater  than  it  really  is : 
for  I  readily  concede  to  Mr.  Herbert,  that  great  numbers,  perhaps  more 
than  half,  of  the  species  enumerated  by  botanical  writers,  may  be  made 
to  breed  together,  with  greater  or  less  degrees  of  facility  :  but  upon  what 
sufficient  evidence  the  originally  specific  diversity  of  these  rests,  I  have 
never  been  able  to  obtain  anything  like  satisfactory  information  ;  and  I 
cannot  by  any  means  admit  that  plants  ought  to  be  considered  of  origi- 
nally distinct  species,  merely  because  they  happen  to  be  found  to  have 
assumed  somewhat  different  forms  or  colours  in  an  uncultivated  state. 
The  genus  Prunus  contains  the  P.  Armeniaca,  P.  Cerasus,  P.  domestica, 
P.  insititia,  P.  spinosa,  P.  sibirica,  and  many  others.  Of  these,  I  feel 
perfectly  confident  that  no  art  will  ever  obtain  offspring  (not  being 
mules)  between  the  Prunus  Armeniaca,  P.  Cerasus,  and  P.  domestica : 
but  I  do  not  entertain  much  doubt  of  being  able  to  obtain  an  endless 
variety  of  perfect  offspring  between  the  P.  domestica,  P.  insititia,  and 
P.  spinosa  ;  and  still  less  doubt  of  obtaining  an  abundant  variety  of 
offspring  from  the  P.  Armeniaca  and  P.  sibirica.  The  former,  the 
common  apricot*,  is  found,  according  to  M.  Regnier  (for  a  translation 
of  whose  account  we  are  indebted  to  Mr.  Salisbury)  •(•,  in  a  wild  state  in 
the  Oases  of  Africa.  It  is  there  a  rich  and  sweet  fruit,  of  a  yellow 
colour.  The  fruit  of  the  P.  sibirica,  seeds  of  which  came  to  me  last  year 
from  Dr.  Fischer  of  Gorenki,  is,  on  the  contrary,  I  understand,  black, 
very  acid,  and  of  small  size  :  but  nevertheless,  if  these  apparently  distinct 

*  The  early  period  at  which  the  apricot  unfolds  its  flowers  leads  me  to  believe  it  to  be  a 
native  of  a  cold  climate  :  and  I  suspect  the  French  word  abricot,  the  English  apricock,  and  the 
African  Berrikokka,  to  have  been  alike  derived  from  the  Latin  word  prsecocia,  which  the 
Romans  (there  is  every  reason  to  be  believe)  pronounced  praikokia,  and  which  was  the  term 
applied  to  early  varieties  of  peaches,  which  probably  included  the  apricot.  The  Greeks  also 
wrote  the  Latia  word,  as  I  suppose  the  Romans  to  have  pronounced  it,  ITpa/co/cia.  Hardouin's 
edition  of  Pliny,  lib.  15.  sec.  xi. 

f  See  Horticultural  Transactions,  Vol.  III.  Appendix,  page  23. 


252  OBSERVATIONS    ON    HYBRIDS. 

species  will  breed  together,  and  I  confidently  expect  they  will,  without 
giving  existence  to  mule  plants,  I  shall  not  hesitate  to  pronounce  these 
plants  of  one  and  the  same  species;  as  I  have  done  relatively  to  the 
scarlet,  the  pine,  and  Chili  strawberries.  Botanists  may  nevertheless,  if 
they  please,  continue  to  call  these  transmutable  plants,  species ;  but  if 
they  do  so,  I  think  they  should  find  some  other  term  for  such  species  as 
are  not  transmutable,  and  which  will  either  not  breed  together  at  all,  or 
which,  breeding  together,  give  existence  to  mule  plants.  I  do  not,  how- 
ever, feel  any  anxiety  or  wish  to  defend  my  own  hypothetical  opinions 
upon  this  subject ;  on  the  contrary,  I  shall  be  most  happy  to  see  them 
proved  erroneous ;  and  my  chief  object  in  addressing  the  present  com- 
munication to  the  Horticultural  Society  is  to  point  out  a  circumstance 
which  is  more  favourable  to  Mr.  Herberts  opinions  than  any  other 
which  has  come  under  my  observations. 

I  sent  to  the  Society,  some  years  ago,  a  fruit  which  sprang  from  a  seed 
of  the  sweet  almond  and  the  pollen  of  a  peach  blossom,  and  which  in  every 
respect  presented  the  character  of  a  perfectly  melting  peach.  When  the 
tree  which  afforded  that  fruit  first  produced  blossoms,  I  introduced  into 
them  the  pollen  of  another  peach-tree,  with  the  view'  of  obtaining  more 
improved  varieties  of  the  peach  of  this  family,  and  the  necessary  prepara- 
tion of  such  blossoms  prevented  my  noticing  an  imperfection  which  I 
have  since  observed  in  them.  Little  or  no  pollen  is  ever  produced  in 
them ;  and  though  the  tree  has  borne  well  subsequently  upon  the  open 
wall,  and  has  produced  perfect  seeds  without  any  particular  attention 
being  paid  to  it,  I  suspect  that  its  blossoms  have  been  fecundated  by 
those  of  some  adjoining  nectarine  trees.  Having,  however,  often  observed 
that  varieties  of  the  same  acknowledged  identical  species,  when  one  was 
in  a  highly  cultivated  and  the  other  in  a  perfectly  wild  state,  did  not 
readily  succeed  when  grafted  upon  each  other,  owing  probably  to  the 
very  different  qualities  of  their  circulating  fluids,  I  conceived  it  possible 
that  the  same  causes  might  have  prevented  a  perfect  union  at  once  taking 
place  between  the  almond  and  peach  tree.  I  therefore  waited  till  I  had 
an  opportunity  of  observing,  in  the  last  summer,  the  blossoms  of  a  second 
generation,  which  proved  in  every  respect  as  imperfect  as  those  of  the 
first  tree,  and,  like  those,  afforded  fruit  and  perfect  seeds  with  the  pollen 
of  an  adjoining  nectarine  tree.  This  result,  which  I  did  not  anticipate, 
appears  interesting ;  but  I  hesitate  in  drawing,  at  present,  any  inferences 
from  it*. 

*  Since  the  foregoing  observations  were  addressed  to  the  Horticultural  Society,  a  tree  which 
sprang  from  a  seed  of  a  sweet  almond  and  pollen  of  the  early  violet  nectarine  has  produced  a 
profusion  of  perfectly  well  organised  blossoms,  with  abundant  pollen,  after  having,  in  the  three 


OBSERVATIONS    ON    HYBRIDS. 


253 


The  vegetable  and  animal  worlds  present  so  much  similarity  in  almost 
everything  which  respects  the  generation  of  offspring,  that  the  extent  to 
which  mules  are  permitted  to  exist  in  the  animal  world  might  have  been 
expected  to  point  out  the  utmost  limits  of  their  existence  amongst  plants  ; 
for  every  animal  is  driven  by  its  instinctive  feelings  to  seek  its  proper 
mate,  whilst  an  unrestrained  and  unlimited  intercourse  between  plants  is 
carried  on  by  the  incidental  operation  of  wind  and  insects.  But  if  the 
fruit-tree  obtained  from  the  almond  and  pollen  of  the  peach  be  a  mule, 
nature  has  already  permitted  it  to  propagate  offspring  to  an  extent 
rarely,  if  at  all,  known  in  the  animal  world.  I  have,  however,  heard  it 
asserted,  that  female  mule  birds  have  been  known  to  breed  under  similar 
circumstances ;  that  is,  with  a  male  of  the  same  species  as  the  male  parent 
of  the  mule  :  but  upon  trying  the  experiment,  it  did  not  succeed  at  all  in 
my  hands.  The  mule  birds  laid  eggs,  apparently  well  organised,  upon 
which  they  sat ;  but  the  eggs  soon  became  putrid ;  and  I  had  good  reason 
to  believe,  that  the  first  pulse  of  life  had  never  beaten  in  any  of  them. 

If  hybrid  plants  had  been  formed  as  abundantly  as  Linnaeus  and  some 
of  his  followers  have  imagined,  and  such  had  proved  capable  of  affording 
offspring,  all  traces  of  genus  and  species  must  surely  long  ago  have  been 
lost  and  obliterated ;  for  the  seed-vessel  even  of  a  monogynous  blossom 
often  affords  plants  which  are  obviously  the  offspring  of  different  male 
parents ;  and  I  believe  I  could  adduce  many  facts  which  would  satisfac- 
torily prove  that  a  single  plant  is  often  the  offspring  of  more  than  one, 
and,  in  some  instances,  of  many  male  parents.  Under  such  circumstances, 
every  species  of  plant  which,  either  in  a  natural  state  or  cultivated  by 
man,  has  been  once  made  to  sport  in  varieties,  must  almost  of  necessity 
continue  to  assume  variations  of  form.  Some  of  these  have  often  been 
found  to  resemble  other  species  of  the  same  genus,  or  other  varieties 
of  the  same  species,  and  of  permanent  habits,  which  were  assumed  to  be 
species  ;  but  I  have  never  yet  seen  a  hybrid  plant,  capable  of  affording 
offspring,  which  had  been  proved,  by  anything  like  satisfactory  evidence, 
to  have  sprung  from  two  originally  distinct  species ;  and  I  must  therefore 
continue  to  believe,  that  no  species  capable  of  propagating  offspring,  either 
of  plant  or  animal,  now  exists,  which  did  not  come  as  such  immediately 
from  the  hand  of  the  Creator. 

Having  spoken,  in  the  preceding  account,  of  mule  birds,  I  will  take 
this  opportunity  of  recording  a  very  singular  circumstance  which  came 

preceding  years,  afforded  imperfect  blossoms  only.  If  such  pollen  prove  efficient,  which  I  see 
no  reason  to  doubt,  either  the  specific  identity  of  the  peach  and  almond,  or  the  transmuta- 
bility  of  the  two  species,  will  be  proved.  But  if  the  peach  be  an  originally  distinct  species, 
where  could  it  have  lain  concealed  from  the  Creation  to  the  reign  of  Claudius  Ccesar  ? 


254  OBSERVATIONS    ON    HYBRIDS. 

under  my  observation,  whilst  I  was  engaged  in  the  experiments  which  I 
have  stated.  A  person  informed  me  that  a  farmer,  who  resided  a  few 
miles  distant  from  me,  possessed  a  mule  bird,  which  was  bred  between 
the  common  hen  and  the  wood-pigeon;  and  which  my  informant  had 
seen,  and  described  with  accuracy  :  I  took,  in  consequence,  the  earliest 
opportunity  of  seeing  the  farmer,  and  the  supposed  mule  bird ;  because 
I  thought  that  nature  had  strictly  prohibited  the  production  of  mules 
between  species  so  distinct,  and  had  usually  made  the  death  of  the  female 
the  price  of  the  attempt.  The  information  I  obtained  was,  that  the 
children  in  his  house  (his  infant  brothers  and  sisters)  had  reared  a  young 
wood-pigeon  and  a  motherless  chicken  together ;  that  these  became  much 
attached  to  each  other,  and  appeared  to  have  paired,  the  wood-pigeon 
constantly  paying  court  to  the  young  hen,  as  he  would  have  done  to  a 
female  of  his  own  species.  The  hen  subsequently  laid  eleven  eggs,  which 
she  sat  upon,  and  produced  one  offspring,  the  bird  in  question.  It  was 
wholly  without  comb,  and  it  had  soft  turgid  nostrils,  extremely  similar  to 
those  of  a  wood-pigeon ;  and  the  whole  profile  of  its  head,  exclusive  of 
the  point  of  the  beak,  bore  a  most  striking  resemblance  to  that  of  its 
supposed  male  parent.  It,  however,  certainly  was  not  the  offspring  of  a 
wood -pigeon,  nor  a  mule ;  for  it  bred  freely.  I  ought  to  have  preserved 
the  bird,  which  was  offered  me,  and  perhaps  I  convict  myself  of  an 
act  of  unpardonable  stupidity  in  not  having  done  so.  But  it  was  a  great 
favourite  with  the  children  who  possessed  it ;  and  I  did  not  like  to  deprive 
them  of  it.  The  animal  physiologist  will  draw  his  own  conclusions 
respecting  these  singular  facts ;  I  do  not  feel  qualified  to  give  an  opinion. 


XLV — UPON    THE    MANAGEMENT    OF    FRUIT-TREES    IN    POTS. 
[Read  before  the  HORTICULTURAL  SOCIETY,  May  8th,  1821.] 

I  HAVE  more  than  once  mentioned,  in  the  Transactions  of  this  Society, 
the  importance  of  giving  to  fruit-trees,  from  which  a  crop  of  fruit  is 
required  very  early  in  the  season,  a  high  degree  of  excitability,  or  the 
power  to  vegetate  very  strongly  in  moderately  low  temperature,  at  the 
period  when  they  are  first  subjected  to  artificial  heat*:  and  I  have 
pointed  out  the  advantages  of  retaining  all  trees,  which  are  intended 
to  afford  such  very  early  crops,  in  potsf.  In  the  present  season,  I  have 

*  See  paper  on  the  Culture  of  the  Pine-apple,  p.  242  ;  also  paper  on  the  Proper  Manage- 
ment of  Fruit-trees  which  are  intended  to  be  forced  very  early,  p.  228. 

f  See  paper  on  Culture  of  Pine-apple,  p.  242. 


ON    THE    MANAGEMENT    OF    FRUIT-TREES    IN    POTS.  255 

endeavoured  to  ascertain  within  how  short  a  period,  in  the  ordinary 
temperature  of  my  pine-stove,  plants  of  the  Chasselas  and  Verdelho 
vine  could  be  made  to  yield  more  mature  fruit. 

The  subjects  of  this  experiment  had  produced  a  crop  of  fruit  previ- 
ously to  midsummer  1820,  and  in  the  following  month  of  July  they  had 
been  taken  from  the  stove,  after  having  been  for  some  time  sparingly 
supplied  with  water,  and  placed  under  a  north  wall ;  in  which  situation 
they  remained  nearly  torpid  till  autumn,  when  they  were  pruned.  Early 
in  the  winter,  I  observed  in  them  strong  symptoms  of  a  disposition 
to  vegetate,  though  they  remained  in  the  cold  and  shaded  situation 
in  which  they  were  first  placed,  when  removed  from  the  stove;  and 
on  the  12th  of  January,  I  found  the  buds  so  much  swollen,  that  I  feared 
the  exposure  to  frost  would  prove  fatal  to  them,  and  the  pots  were  con- 
sequently removed  to  the  stove. 

In  this,  the  sudden  increase  of  temperature  occasioned  every  visible 
bud  to  unfold  itself  within  a  very  few  days ;  and  on  the  17th  of  the 
following  month,  being  thirty-six  days  after  the  pots  were  brought  into 
the  stove,  the  berries  of  some  bunches  of  the  Verdelho  grape  were 
so  far  grown,  that  I  could  have  thinned  them  with  advantage.  In 
the  end  of  March,  the  Chasselas  grapes  became  soft  and  transparent, 
and  in  the  middle  of  April  some  bunches  were  as  mature,  and  much 
more  yellow,  than  those  of  the  same  kind  usually  are  when  first  brought 
to  the  London  market  in  the  spring ;  though  the  weather  had  been, 
during  the  early  part  of  the  spring,  dark  and  cloudy,  and  consequently 
unfavourable.  The  wood  of  these  vines  appeared  nearly  mature  in  the 
end  of  the  last  month  (April) ;  and  by  removing  them  from  the  stove 
for  a  short  time  to  a  cold  and  shaded  situation,  and  subsequently 
replacing  them  in  the  stove,  I  do  not  doubt  the  practicability  of  obtain- 
ing another  crop  from  them  within  the  present  year. 

A  pot  which  contains  a  quantity  of  mould  equal  to  a  cube  of  fourteen 
inches  has  been  found  large  enough  for  a  vine  whose  foliage  occupied  a 
space  of  twenty  square  feet;  water  holding  manure  in  solution  being 
abundantly  given :  and  I  have  seen  grapes  acquire  a  larger  size,  and 
other  fruits  a  higher  flavour,  under  such  management  than  under  any 
other. 

The  supposed  necessity  of  frequently  removing  fruit-trees  which  grow 
in  pots,  to  other  pots  of  larger  dimensions,  appears  to  present  a  good 
deal  of  inconvenience ;  but  I  have  readily  obviated  this  necessity  by 
means  which  I  can  confidently  recommend  to  the  attention  of  gardeners. 
When  the  plant  or  fruit-tree  is  first  placed  in  the  pot  in  which  it  is  long 


256  ON    THE    MANAGEMENT    OF    FRUIT-TREES    IN    POTS. 

to  remain,  I  mix  with  the  compost  some  material,  in  greater  or  less 
quantity,  which  is  capable  of  ultimately  affording  nutriment,  but  which 
will  decompose  slowly.  In  some  cases  I  have  used  with  success  slender 
half-decayed  branches  from  my  wood  pile  ;  and  in  others  I  have  employed 
sound  chips,  chiefly  of  apple-tree,  mixed  with  mould,  and  in  sufficient 
quantity  to  occupy  at  least  one-fourth  of  the  space  afforded  by  the  pot. 
As  the  roots  of  the  plant  increase,  the  lifeless  wood  gradually  decomposes, 
at  the  same  time  giving  food  and  space  to  the  roots,  which  consequently 
do  not  become  injuriously  compressed  in  the  pot.  I  possess  a  nectarine- 
tree  which  has  grown  nine  years  in  the  same  pot,  and  which  vegetated 
more  strongly  in  the  present  spring  than  I  can  recollect  it  previously  to 
have  done.  Several  successive  crops  of  fungi  usually  appear  upon  the 
surface  of  the  pots  under  the  preceding  circumstances ;  but  I  have  had 
no  reason  to  think  these  injurious. 

The  trouble  of  conveying  water  to  numerous  pots,  in  hot  weather, 
would  be  very  considerable;  but  a  simple  mode  of  applying  the  very 
ingenious  contrivance  of  Mr.  Loddiges,  by  which  water  is  dispersed  as 
in  showers  upon  the  foliage  of  his  plants,  and  which  has  been  described 
in  the  Society's  Transactions*,  would  reduce  this  labour  to  the  act  of 
turning  a  cock  :  and  if  it  were  desirable  to  diminish  or  wholly  take  away 
the  supply  from  any  particular  spot,  this  might  easily  be  effected,  by 
partially  or  wholly  closing  the  apertures  through  which  the  water  is 
made  to  escape  from  the  pipe. 


XLVI.— AN  ACCOUNT    OF    AN    IMPROVED    METHOD    OF   RAISING    EARLY 
POTATOES   IN   THE    OPEN   GROUND. 

[Read  before  the  HORTICULTURAL  SOCIETY,  June  5th,  1821.] 

THE  destruction,  in  the  present  season,  of  early  crops  of  potatoes  by 
frost  in  this  vicinity,  (particularly  in  the  gardens  of  those  who  could  ill 
bear  the  loss  they  have  sustained,)  has  led  me  to  address  to  the  Society 
the  following  account  of  some  deviations  from  the  ordinary  modes  of 
practice  in  the  culture  of  that  plant,  which  I  have  found  successful  in 
not  only  affording  plants  which  more  effectually  recover  when  impeded 
by  frost,  but  also  in  furnishing  a  larger  and  more  early  produce  under 
ordinary  circumstances. 

It  has  long  been  known  that  abundant  crops  of  late  and  luxuriant  varie- 
ties of  early  potatoes  may  be  obtained  by  planting  very  small  pieces  only 

*  See  Vol.  III.  page  14  of  the  Transactions  of  the  Horticultural  Society. 


AN    IMPROVED    METHOD    OF    RAISING    EARLY    POTATOES.  257 

of  their  tuberous  root :  for  the  plants  of  those  varieties  always  acquire  a 
considerable  age  before  they  begin  to  generate  tubers,  and  therefore  do 
not  too  soon  begin  to  expend  themselves  in  the  production  of  tubers ;  and 
the  size  which  these  acquire  within  any  given  period  in  the  spring  will  be 
to  a  great  extent  regulated  by  the  strength  of  the  plants,  at  the  period 
when  they  first  spring  from  the  soil ;  and  strong  plants  of  such  varieties 
can  be  afforded  only  by  sets  of  considerable  size.  I  have,  in  consequence, 
for  some  years  past,  selected  in  the  autumn  the  largest  tubers,  and  these 
nearly  of  an  equal  size,  for  planting  in  the  spring ;  and  I  have  found  that 
these  not  only  uniformly  afford  very  strong  plants,  but  also  such  as 
readily  recover  when  injured  by  frost :  for  being  fed  by  a  copious 
reservoir  beneath  the  soil,  a  reproduction  of  vigorous  stems  and  foliage 
soon  takes  place,  when  those  first  produced  are  destroyed  by  frost,  or 
other  cause. 

When  the  planter  is  anxious  to  obtain  a  crop  within  the  least  possible 
time,  he  will  find  the  position  in  which  the  tubers  are  placed  to  vegetate 
by  no  means  a  point  of  indifference  ;  for  these  being  shoots,  or  branches, 
which  have  grown  thick  instead  of  elongating,  retain  the  disposition  of 
branches  to  propel  their  sap  to  their  leading  buds,  or  points  most  distant 
from  the  stems  of  the  plants  of  which  they  once  formed  parts.  If  the 
tubers  be  placed  with  their  leading  buds  upwards,  a  few  very  strong  and 
very  early  shoots  will  spring  from  them  ;  but  if  their  position  be  reversed, 
many  weaker  and  later  shoots  will  be  produced  ;  and  not  only  the 
earliness,  but  the  quality  of  the  produce  in  size,  will  be  much  affected. 

In  the  spring,  when  the  young  plants  are  just  beginning  to  appear  in 
the  rows,  I  have  often  found  it  very  advantageous  to  raise  the  mould  over 
them  in  ridges  by  an  operation  perfectly  similar  to  moulding  the  plants. 
Protection  has  been  thus  given  against  frost,  and  I  have  not  found  the 
period  of  maturity  of  the  crop  to  have  been  in  any  degree  retarded. 

It  has  been  contended  that  there  is  much  waste  in  the  practice  above 
described  of  planting  large  sets  ;  because  the  old  tuber  is  often  found  to 
have  lost  little  in  weight,  when  an  early  crop  is  taken  up  in  an  immature 
state  :  and  it  has  thence  been  inferred,  that  a  very  small  part  only  of  the 
matter  of  the  old  tubers  enters  into  the  composition  of  the  new.  But 
I  believe  a  false  inference  has  in  this  case  been  drawn,  and  that,  under 
ordinary  circumstances,  a  very  large  portion  of  the  soluble  matter  of  the 
old  tubers  is  employed  in  the  formation  of  the  new ;  for  I  have  proved 
by  experiments  purposely  made,  that  the  vital  union,  and  community  of 
circulating  fluid,  between  the  old  tuber  and  the  plant  which  has  sprung 
from  it,  is  not  so  soon  dissolved. 


258  AN    IMPROVED    METHOD    OF    RAISING    EARLY    POTATOES. 

Some  potatoes  of  rather  large  size  and  early  habit  were  placed  in  such 
situations  that  the  fibrous  roots  only  of  the  plants  entered  into,  or  were 
in  contact  with,  the  soil.  Thus  circumstanced,  an  abundant  blossom 
appeared,  and  seeds  would  have  been  produced  ;  but  both  the  blossoms, 
and  the  runners  which  would  have  formed  young  tubers,  were  alike 
removed. 

The  old  tubers,  though  fully  exposed  to  the  sun  and  air,  still  retained 
life,  and  were  obviously  supplied  with  moisture  by  the  stems,  which  had 
sprung  from  them ;  and  the  result  was  ultimately  just  what  I  had 
anticipated.  The  plants,  after  many  frustrated  efforts  to  produce 
blossoms  and  tubers  upon  every  part  of  their  branches,  at  last  threw 
their  sap  back  into  the  old  tubers  ;  and  a  numerous  crop  of  young  tubers 
was  suspended  from  the  buds,  or  eyes,  of  the  old.  This  did  not  occur  till 
autumn ;  and  therefore  the  vital  union  must  have  subsisted  through  the 
whole  summer ;  and  I  entertain  but  very  little  doubt,  that  such  a  union 
subsists  under  ordinary  circumstances,  till  almost  the  whole  of  the  soluble 
and  organisable  matter  of  the  old  tubers  has  been  absorbed  by  the  new. 
To  what  extent  this  occurs  is,  however,  a  point  of  little  consequence  :  the 
important  fact  of  the  crop  being  increased  by  the  employment  of  large 
sets  has  been  proved  by  accurate  experiments,  in  many  successive  seasons. 


XLVIL— ON    GRAFTING    THE    VINE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  September  18th,  1821.] 

THE  practice  of  grafting  the  vine  appears  to  be  very  ancient ;  for  it  is 
mentioned  both  by  Cato  and  Columella*  in  a  way  which  shows  that  it 
was  common  in  the  vineyards  of  Italy  at  the  period  in  which  they  wrote. 
It  must,  consequently,  have  been  an  operation  of  easy  execution,  though  it 
is  rarely  seen  to  succeed  well  in  the  hands  of  the  modern  gardener ;  who 
is,  nevertheless,  certainly  much  better  provided  with  instruments,  and 
can  scarcely  be  supposed  to  be  inferior  in  skill  or  science  to  the  culti- 
vators of  that  period.  It  is  therefore  probable,  that  the  ancients  were 
acquainted  with  some  mode  of  operating,  of  which  the  modern  gardener 
is  ignorant.  It  is  well  known  that  the  ancients,  in  propagating  the  vine, 
employed  cuttings,  which  consisted  partly  of  year- old,  and  partly  of  two- 
year-old  wood  ;  and  the  modern  gardener,  in  deviating  from  this  mode 
of  practice,  has  adopted  one  which  does  not  possess  a  single  advantage, 

*  Cato,  cap.  42.     Columella,  lib.  IV.  c.  29. 


ON     GRAFTING    THE    VINE.  259 

and  which  is  in  every  respect  worse.  I  conceived  it  probable,  in  the  last 
spring,  that  the  success  of  the  Roman  cultivators  in  grafting  their  vines 
might  have  arisen  from  the  selection  of  grafts  similar  to  their  cuttings ; 
and  the  result  of  the  following  experiment  leads  me  to  believe  my  conjec- 
ture to  be  well  founded.  I  selected  three  cuttings  of  the  black  Hamburgh 
grape,  each  having  at  its  base  one  joint  of  two  years  old  wood.  These 
were  inserted  in,  or  rather  fitted  to,  branches  of  nearly  the  same  size, 
but  of  greater  age  ;  and  all  succeeded  most  perfectly.  The  clay  which 
surrounded  the  base  of  the  grafts  was  kept  constantly  moist ;  and  the 
moisture  thus  supplied  to  the  graft  operated  very  beneficially  at  least,  if 
it  was  not  essential  to  the  success  of  the  operation.  A  very  skilful 
gardener  in  my  vicinity,  to  whom  I  mentioned  my  intention  of  trying  the 
foregoing  experiment,  was  completely  successful  by  a  somewhat  different 
method.  He  used  grafts  similar  to  mine  ;  but  his  vine  grew  under  the 
roof  of  the  hot-house,  in  which  situation  he  found  it  difficult  to  attach 
such  a  quantity  of  clay  as  would  supply  the  requisite  degree  of  moisture 
to  the  graft,  and  he  therefore  supported  a  pot  under  each  graft,  upon 
which  he  raised  the  mould  in  heaps  sufficiently  high  to  cover  the  grafts, 
and  supply  them  with  moisture. 

Some  very  intelligent  gardeners  have  asserted,  that  they  have  seen  the 
berries  of  some  of  the  smaller  varieties  of  grape  enlarged  by  the  use  of 
stocks  of  larger  or  more  luxuriant  varieties. 

I  possess  no  information  relative  to  this  statement ;  and  the  object  of 
this  communication  is  merely  to  point  out  the  means  by  which  new 
varieties  may  be  introduced  into  the  forcing-house  without  loss  of  time 
or  produce. 

The  grafts  which  I  used  consisted  of  about  two  inches  of  old  wood,  and 
five  of  annual  wood,  by  which  means  the  junction  of  the  new  and  old 
wood,  at  which  point  cuttings  most  readily  emit  shoots  and  receive 
nutriment,  was  placed  close  to  the  head  of  the  stock,  and  a  single  bud 
only  was  exposed  to  vegetate. 


260 


XLVIII.— FURTHER    OBSERVATIONS    ON    THE    CULTIVATION    OF    THE 

PINE-APPLE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  March  5,  1822.] 

THE  following  circumstances,  relative  to  the  habits  of  the  pine-apple 
plant,  appear  to  me  so  interesting  and  singular,  that  I  am  induced  now 
to  send  an  account  of  them  to  the  Horticultural  Society,  though  I  have 
so  recently  addressed  a  communication*  upon  nearly  the  same  subject. 
In  that  communication  I  mentioned  the  extraordinary  growth  of  a  pine- 
apple, which  had  passed  the  whole  of  the  last  summer  and  autumn  in 
very  low  temperature,  and  which  then,  in  the  beginning  of  November, 
continued  to  increase  in  size,  four  months  having  at  that  time  elapsed, 
since  the  period  of  its  blossoming.  I  saw  the  same  fruit  in  the  first 
week  of  the  last  month  (February),  when  it  still  continued  perfectly 
green,  and  apparently  growing  rapidly.  Our  member  Mr.  M earns,  who 
has  had  not  only  the  advantages  of  long  and  very  attentive  experience, 
but  who  has  also  visited  the  stoves  of  a  very  great  number  of  the  most 
celebrated  cultivators  of  the  pine-apple  in  different  parts  of  the  kingdom, 
has  been  to  view  the  fruit  above  mentioned;  and  he  assures  me  that  he 
has  never  seen  a  queen  pine-apple  growing  upon  so  small  a  plant,  so  per- 
fectly well  swelled  out,  in  any  season  of  the  year,  under  any  circum- 
stances. He  was  of  opinion,  when  he  saw  it,  which  was  early  in  the 
last  month,  that  it  would  probably  ripen  about  the  end  of  the  present 
month,  or  early  in  April.  It  had  passed  the  winter  in  the  temperature 
which  is  usually  given  to  common  green-house  plants,  and  it  had  certainly 
not  had  the  advantages  in  any  degree  of  judicious  management,  having 
been  very  irregularly,  and  at  times  much  too  profusely,  supplied  with 
water.  What  will  be  the  merits  of  it  when  ripe,  time  alone  can  show ; 
but  I  shall  here  observe,  that  I  have  found  all  fruits  (and  particularly 
the  melon)  to  acquire  their  highest  state  of  excellence  when  their  growth 
has  been  slow — provided  it  has  been  regularly  progressive,  and  that 
the  fruit  has  ultimately  attained  its  proper  size  and  perfect  maturity ; 
and  I  believe,  that  no  fruit  has  ever  been  seen  perfect,  either  in  taste  or 
flavour,  the  growth  and  maturity  of  which  had  been  greatly  accelerated 
by  much  fire-heat,  and  of  necessity,  abundant  water.  I  am,  therefore, 
much  inclined  to  believe,  that  the  pine-apple  will  be  found  to  acquire 
its  highest  state  of  excellence,  when  a  considerable  time  elapses  between 
the  period  of  its  blossom  and  that  of  its  maturity. 

Should  it  be  found  easily  practicable,   as  I  very  confidently  believe 

*  See  above,  page  242. 


ON    THE    CULTIVATION    OF    THE    PINE-APPLE.  261 

it  will,  to  retard  the  ripening  of  the  fruit  of  those  plants  of  the  pine- 
apple which  blossom  late  in  the  summer,  or  early  in  the  autumn,  such 
fruit  might  be  made  to  supply  our  tables  abundantly  in  the  spring  or 
early  summer  months. 

Since  my  last  paper  upon  the  management  of  the  pine-apple  plant 
was  written,  I  have  placed  a  few  plants,  which  have  blossomed  in  autumn, 
in  very  high  temperature  (generally  above  that  of  80°),  and  very  near 
to  white  glass  of  good  quality;  and  so  circumstanced,  even  the  queen 
pine-apple  has  swelled  nearly,  if  not  quite,  as  rapidly,  as  it  usually  does 
in  the  best  seasons  of  the  year,  and  its  taste  and  flavour  have  been  quite 
as  good  as  those  of  that  kind  usually  are  in  winter.  Other  varieties  have 
succeeded  better,  and  one  which  I  received  without  a  name  from  the 
West  Indies,  and  which  I  am  informed  is  the  St.  Vincent's  pine-apple, 
acquired,  in  the  last  month,  a  degree  of  excellence  both  in  taste  and 
flavour  which  I  have  rarely  found  equalled  in  any  season*. 


XLIX.— DESCRIPTION     OF    A     MELON    AND    PINE     PIT. 

[Read  befo/e  the  HORTICULTURAL  SOCIETY,  July  16th,  1822.] 

I  SENT  an  account  to  the  Horticultural  Society,  in  the  last  springt,  of 
a  pine-apple,  which,  having  blossomed  in  the  month  of  July,  did  not 
ripen  till  the  following  month  of  April,  owing  to  its  having  passed  the 
autumn  and  winter  in  low  temperature  ;  and  I  thence  inferred  that  pine- 
apples might  easily  be  so  managed  as  to  supply  the  market  abundantly 
in  seasons  when  few  species  of  fruit  can  be  obtained.  In  the  present 
spring  I  erected  a  small  pine-pit  upon  a  new  construction,  for  the  purpose 
of  ascertaining,  by  experiment  upon  a  few  plants,  whether  my  opinions 
were  well  founded ;  but  not  having  more  plants  than  my  houses  could 

NOTE  BY  THE  SECRETARY,  JOS.  SABINE,  ESQ. 

*  A  few  days  after  this  paper  was  read  to  the  Society,  being  on  a  visit  to  the  president,  at 
Downton,  I  had  the  gratification  of  observing  the  condition  and  appearance  of  the  pine-apple 
plants  described  by  him  in  the  communication  above  referred  to  ;  the  plants,  which  were 
expected  to  begin  showing  their  fruit  in  the  next  month,  though  young,  were  remarkable  for 
their  vigour  and  strength.  They  were  grown  in  pots  of  much  larger  size  than  usual,  which  were 
raised  so  as  to  bring  the  upper  leaves  nearly  in  contact  with  the  glass.  The  plants  themselves 
were  firmly  rooted  in  the  mould,  their  leaves  were  of  peculiar  breadth  and  substance,  the  stems 
were  short  and  of  unusual  thickness,  and  the  whole  had  the  appearance  of  extraordinary 
health. 

t  See  the  preceding  paper.  The  experiment  has  since  been,  in  many  instances,  repeated, 
with  similar  results. 


262  DESCRIPTION    OF    A    MELON    AND    PINE    PIT. 

conveniently  contain,  I  have  applied  the  structure  erected  for  pine-apple 
plants  to  the  culture  of  melons  only,  during  the  summer. 

These  having  succeeded  most  admirably,  and  a  great  number  of 
gardeners  having  examined  my  machinery,  and  given  their  unqualified 
approbation  of  it,  I  send  the  following  description  of  it  to  the  Horticul- 
tural Society,  flattering  myself  that  it  will  be  found,  in  the  aggregate, 
superior  to  any  now  employed,  which  can  be  erected  at  so  small  an 
expense,  and  managed  with  so  little  cost  and  trouble.  It  consists  of  a 
hollow  wall,  similar  in  every  respect,  as  to  construction,  to  that  described 
by  Mr.  Silverlock  in  the  Transactions  of  the  Society*;  and  I  cannot 
describe  it  better  than  by  using  his  words :  "  It  is  built  nine  inches  thick, 
with  sound  even-sized  bricks,  placed  edgeways,  the  joints  being  carefully 
made,  and  laid  with  the  very  best  mortar.  The  bricks  are  placed  with 
their  faces  and  ends  alternately  to  the  outside,  so  that  those  which  have 
their  ends  exposed  become  ties  to  the  surfaces  of  the  wall.  In  each 
succeeding  course,  as  the  wall  is  built,  the  bricks  with  their  ends  out- 
wards are  placed  on  the  centre  of  the  bricks  which  are  laid  lengthways 
in  the  course  below.  Thus  a  hollow  space  is  formed  in  the  middle  of  the 
wall,  of  four  inches  in  width,  which  is  only  interrupted  where  the  tying 
bricks  cross  it,  but  there  is  a  free  passage  for  air  from  top  to  bottom  of 
the  wall." 

My  front  wall  is  four  feet,  and  my  back  wall  five  feet  six  inches  high, 
enclosing  a  space  of  six  feet  wide  and  fifteen  feet  long,  and  the  walls  are 
covered  with  a  wall-plate,  and  with  sliding  lights,  as  in  ordinary  hot- 
beds. 

The  space  included  may  be  filled  to  a  proper  depth  with  leaves,  or 
tan,  when  it  is  wished  to  promote  the  rapid  growth  of  plants ;  but  at 
present  it  contains  only  nine  large  pots,  in  which  the  melon  plants  grow, 
and  the  stems  of  these  are  supported  by  a  trellis  at  a  proper  distance 
from  the  glass.  The  wall  is  externally  surrounded  by  a  hot-bed  com- 
posed of  leaves  and  horse-dung,  by  which  it  is  kept  warm;  and  the  warm 
air  contained  in  its  cavity  is  permitted  to  pass  into  the  inclosed  space 
through  many  small  perforations  in  the  bricks.  At  each  of  the  lower 
corners  is  a  passage,  which  extends  along  the  surface  of  the  ground, 
under  the  fermenting  material,  and  communicates  with  the  cavity  of  the 
wall,  into  which  it  admits  the  external  air  to  occupy  the  place  of  that 
which  has  become  warm  and  passed  into  the  pit.  The  entrances  into 
these  passages  are  furnished  with  grates,  to  prevent  the  ingress  of  vermin 
of  every  kind.  The  hot-bed  is  moved  and  renewed  in  small  successive 

*  See  Horticultural  Transactions,  vol.  IV.  page  224. 


DESCRIPTION    OF    A    MELON    AND    PINE    PIT.  263 

portions,  so  that  the  temperature  may  be  permanently  preserved,  the 
ground  being  made  to  descend  a  little  towards  the  wall  on  every  side, 
that  the  bed  in  shrinking  may  rather  fall  towards  than  from  the  walls; 
and  I  entertain  no  doubt  but  that  the  perpetual  ingress  of  warm  air, 
even  without  an  internal  leaf-bed,  will  prove  sufficient  to  preserve  pine- 
apple-plants without  the  protection  of  mats,  except  in  very  severe 
weather.  I  have  nothing  further  to  add,  but  that  the  melon  plants 
are  the  most  healthy  and  luxuriant  that  I  ever  possessed,  and  that  their 
fruit  is  swelling  with  more  than  ordinary  rapidity.  I  annex  (plate  6)  a 
sketch  of  a  section  and  plan  of  the  pit,  without  which,  I  fear,  the  preceding 
account  would  scarcely  prove  intelligible. 

The  perforations  in  the  interior  of  the  wall,  are  from  eighteen  to  nearly 
twenty  inches  distant  from  each  other,  and  they  do  not  begin  till  the  fifth 
row  of  bricks  from  the  bottom.  When  the  pit  is  intended  for  early  cucum- 
bers or  melons,  and  the  lower  part  is  consequently  to  be  filled  with  leaves 
or  tan,  the  holes  in  the  bricks  should  only  be  made  above  the  surface  of 
whatever  may  be  put  into  the  pit,  or,  if  previously  made  below,  must  be 
closed. 

REFERENCES     TO     PLATE     6. 

A.    Sliding  lights.  D.    Hollow  wall. 

B  B.    Wall  plates.  E.    Dung  linings. 

C.    Water  groove.  F.    Air  funnels. 


L.— UPON    THE    ADVANTAGES     AND    DISADVANTAGES    OF    CURVILINEAR 
IRON    ROOFS    TO    HOT-HOUSES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  October  1st,  1822.] 

A  WISH  has  more  than  once  been  expressed  to  receive  from  me  an 
account  of  my  opinion  of  the  comparative  advantages  and  disadvantages 
of  the  iron  curvilinear,  and  common  hot-house  roofs  of  sliding  lights,  in  the 
culture  of  the  pine-apple,  as  soon  as  experience  should  have  enabled  me 
to  give  it.  I  am  now,  I  believe,  in  possession  of  sufficient  information  to 
enable  me  to  give  an  opinion  with  some  degree  of  confidence,  having  had 
the  experience  of  three  summers,  in  which  I  have  nearly  sacrificed  more 
than  two  hundred  very  fine  fruiting  pine-apple  plants  in  my  curvilinear 
roofed  hot-house.  I  have,  however,  ultimately  succeeded  to  the  full 
extent  of  my  hopes  and  expectations,  and  I  give  a  decided  preference  to 
the  curvilinear  roof.  I  must  nevertheless  admit,  that  it  has  some  defects, 
which  I  shall  endeavour  to  point  out,  and  set  in  opposition  to  its  per- 
fections. 


264  ON    CURVILINEAR    IRON    ROOFS    TO    HOTHOUSES. 

The  curvilinear  iron  roof  certainly  transmits  heat  more  rapidly  than 
one  of  wood  of  the  ordinary  construction,  but  not  to  any  considerable 
extent,  I  think,  more  rapidly  than  a  roof  composed  of  wood  and  glass 
would  do,  if  the  wood  were  employed  in  as  small  quantities  as  the  iron  is, 
and  not  nearly  to  as  great  an  extent  as  a  roof  composed  wholly  of  glass 
would  do,  if  such  could  be  constructed. 

My  house  is  fifty  feet  long,  and  ten  feet  wide,  and  it  is  heated  by  a 
single  fire  of  moderate  size;  and  I  have  found  that  single  fire  fully 
sufficient  to  keep  pine-apple  plants  in  a  healthy  growing  state,  in  all 
seasons  of  the  year,  without  the  aid  of  bark  or  hot-bed  of  any  kind,  and 
without  the  protection  of  any  kind  of  covering  *.  I  have  always  used  it 
as  a  fruiting-house,  and  my  plants,  after  being  placed  in  it,  have  grown 
admirably,  and  have  shown  fruit  well ;  but  the  fruit  has  never  till  the 
present  year,  except  in  one  instance,  when  the  plants  stood  close  to  the 
door,  swelled  properly.  Its  taste  and  flavour  have  nevertheless  been 
good,  and  it  constantly  ripened  in  a  singularly  short  time. 

The  fruit  which  appeared  in  September  and  October,  in  the  last 
autumn,  became  ripe  in  January,  and  whenever  one  fruit  became  ripe,  its 
aroma  appeared  to  accelerate  the  maturity  of  all  in  its  vicinity. 

The  queen  pine-apples  were  generally  very  similar  to  those  I  have 
usually  seen  at  the  shops  in  London  in  the  months  of  April  and  May ; 
and  with  imperfections  arising,  I  believe,  from  the  same  source,  the  want 
of  efficient  ventilation. 

In  houses  of  ordinary  construction,  with  roofs  of  sliding  lights,  air 
enters  and  escapes  at  all  times  with  much  rapidity ;  and  the  consequent 
change  of  air  is  very/nearly,  if  not  wholly,  sufficient  to  enable  the  pine- 
apple to  acquire  maturity  and  perfection  at  all  seasons  ;  provided  the 
flues  operate  with  sufficient  power  to  give  the  requisite  temperature. 
But  in  my  house,  with  a  curvilinear  roof,  I  acquired  the  power  of  almost 
wholly  preventing  any  change  of  air  whatever  ;  and  I  exercised  that  power 
too  extensively,  after  the  fruit  was  shown,  and  particularly  after  a  part 
of  it  had  nearly  acquired  maturity.  In  the  last  spring  I  adopted  a  mode 
of  ventilation,  from  which  I  expected  to  derive  all  the  advantages  of 
change  of  air,  without  materially  lowering  the  temperature  of  the  house  ; 
and  the  success  of  it  has  greatly  exceeded  the  expectations  I  had  enter- 
tained. I  shall  best  be  able  to  show  the  advantages  of  this  mode  of 

*  A  much  higher  temperature  than  my  machinery  enables  me  to  give,  and  varying  from  75° 
to  90°  in  winter,  and  from  80°  to  105°  in  summer,  would,  however,  be  highly  beneficial :  and  I 
feel  quite  confident  that  in  a  dry  stove  of  such  temperature  pine-apples  might,  under  appro- 
priate management,  be  abundantly  ripened,  and  in  considerable  perfection,  in  any  part  of  the 
year. 


ON    CURVILINEAR    IRON    ROOFS    TO    HOTHOUSES.  265 

ventilation,  by  giving  (plate'1?)  a  slight  sketch  of  the  form  of  a  section  of 
my  house,  in  which  D  marks  the  position  of  cylindrical  passages  of  nearly 
two  inches  diameter  through  the  front  wall.  Through  these,  which  are 
placed  eighteen  inches  distant  from  each  other,  along  the  whole  front 
wall  of  the  house,  the  air,  whenever  the  weather  is  warm,  is  suffered  to 
enter  freely,  and  its  entrance  is  at  other  times  more  or  less  obstructed 
in  proportion  to  its  coldness  :  but  it  is  never  wholly  excluded,  except 
during  the  nights  in  very  severe  weather. 

The  passages  through  the  front  wall  are  placed  at  just  such  a  distance 
from  the  ground,  as  will  occasion  them  to  direct  the  air,  which  enters, 
either  into  contact  with,  or  to  pass  closely  over,  the  heated  covers  of  the 
flue.  It  consequently  becomes  heated,  and  is  impelled  amongst  the  pine- 
apple plants,  which  stand  in  rows  behind  each  other,  each  row  of  plants 
being  so  far  elevated  above  that  before,  as  to  place  every  plant  at  nearly 
an  equal  distance  from  the  glass  roof.  A  thermometer  was  placed  at  H, 
being  equally  distant  from  each  end  of  the  house,  and  I  had  the  satisfac- 
tion to  observe,  that  the  temperature  of  that  part  of  the  house  in  which 
the  thermometer  stood  was  raised  between  two  and  three  degrees,  when 
the  external  air  was  at  40°.  This  effect  was,  I  conclude,  produced  by  the 
heated  air  being  impelled  into  the  body  of  the  house  amongst  the 
plants,  instead. of  being  permitted  to  rise,  as  it  had  previously  done,  and 
to  come  instantly  into  contact  with  the  roof :  and  by  suspending  light 
bodies  amongst  the  plants,  I  ascertained  that  the  previously  confined 
air  was  thus  constantly  kept  in  a  state  of  rapid  motion.  The  air  is 
suffered  to  escape  through  passages  of  four  inches  wide  and  two  inches  and 
a  half  high,  at  E,  which  passages  are  placed  at  the  same  equal  distances 
as  those  in  the  front  wall,  and,  like  those,  are  opened  or  closed  as  circum- 
stances require.  The  trouble  of  opening  or  closing  such  passages,  after 
substances  of  proper  form  are  prepared  and  suspended  for  the  purpose, 
is  very  small,  much  less,  I  think,  than  that  of  moving  the  lights  of  any 
house  of  ordinary  construction ;  and  the  effect  of  the  kind  of  ventilation 
obtained  upon  the  growth  of  my  plants  and  fruit,  is  everything  I  wish 
it  to  be. 

I  have  stated  that  my  whole  house  is  heated  by  a  single  flue  :  this 
enters  at  the  west  end  of  it,  and  thence  passes  along  the  whole  front 
within  sixteen  inches  of  the  wall.  It  then  returns  twenty  feet  towards 
the  middle  of  the  house  and  back  again,  the  smoke  escaping  at  the  end 
opposite  to  that  which  it  enters.  The  flue  is  consequently  single  at  the 
end  of  the  house,  which  adjoins  the  fire  place,  and  triple  in  the  last 
twenty  feet  of  the  opposite  end ;  by  which  means  a  nearly  equal 
temperature  is  everywhere  given. 


266  ON    CURVILINEAR    IRON    ROOFS    TO    HOTHOUSES. 

It  has  been  objected,  that  the  water  which  drops  from  bars  of  iron  is 
extremely  noxious  to  pine-apple  plants ;  but  I  have  not  found  this  to  be 
in  any  degree  the  case  :  for  having  placed  a  plant  in  such  a  situation  that 
the  water  from  a  cast-iron  rafter  dropped  upon  it,  in  summer,  and 
removing  it  only  as  soon  as  the  mould  became  sufficiently  moist,  I  could 
not  discover  that  the  plant  had,  during  a  month,  sustained  the  slightest 
injury.  Another  objection  made  to  iron  roofs  is,  that  the  metal  is  very 
subject  to  rust.  This  is  perfectly  true,  provided  they  be  not  kept  well 
painted  ;  but  if  one-third  of  the  sum  requisite  to  keep  a  wooden  roof 
properly  painted  be  expended  upon  the  iron  roof,  no  injury  will  ever  be 
sustained  from  the  liability  of  that  to  suffer  from  rust.  I  must,  however, 
take  this  opportunity  of  observing,  that  the  bars  of  all  the  iron  roofs  I 
have  yet  seen  have  been  exceedingly  ill-formed.  The  metal,  instead  of 
being  rolled  thin  with  grooves,  and  made  to  descend  into  the  house  far 
below  the  level  of  the  glass,  should  be  compressed  into  the  least  compass 
consistent  with  sufficient  strength ;  and  its  lower  surface,  instead  of 
being  brought  to  a  thin  edge,  should  be  hemicylindrical  in  form.  None 
of  the  edges  or  angles  which  are  now  presented,  and  which  are  most 
subject  to  rust,  would  then  exist ;  less  shade  would  be  thrown  upon  the 
plants  in  the  mornings  and  evenings ;  and  the  condensed  steam  would  be 
less  subject  to  drop  from  the  bars  upon  the  plants ;  though  this,  in  a 
house  constructed  as  mine  is,  can  never  do  any  injury. 

I  have  remarked,  in  a  former  communication,  that  I  suspected  pine- 
apple plants  might  suffer  under  the  influence  of  a  bright  sun  during  the 
whole  length  of  an  English  summer's  day,  in  a  hot-house  with  a  curvilinear 
roof  such  as  mine,  if  the  glass  were  of  good  quality.  I  am  not  prepared 
positively  to  say  whether  such  apprehensions  are  well  or  ill-founded : 
but  I  have  thought  it  best  to  be  provided  with  a  net,  such  as  those 
usually  employed  to  protect  fruit-trees,  of  proper  form  to  cover  my 
house,  if  necessary ;  and  I  am  satisfied  that  I  could  have  used  it  with 
advantage,  if  I  had  possessed  it,  in  some  very  hot  days  in  the  beginning 
of  June. 

The  ends  of  my  house  are  of  brickwork ;  but  I  think  the  end  opposite 
the  door  ought  to  contain  a  window  of  about  two  feet  square,  to  permit 
a  free  passage  of  air  through,  upon  the  door  being  opened  in  very  hot 
weather :  my  own  house  is,  however,  without  one. 

In  conclusion,  I  wish  to  observe,  that  a  curvilinear  iron  roof  may  be 
erected  at  much  less  expense  than  one  of  wood :  two  shillings  and  six- 
pence a  foot  being,  I  conceive,  a  fully  remunerating  price  to  the  builder 
of  such  a  house  as  mine,  the  glass  being  white,  and  of  the  quality  called 


ON    CURVILINEAR    IRON    ROOFS    TO    HOTHOUSES.  267 

lest  seconds.  Green  glass  might  be  afforded  on  much  lower  terms  ;  but  I 
do  not  recommend  it,  being  confident  that  in  our  climate  pine-apple 
plants  suffer  a  hundred  days  by  want  of  light,  for  one  in  which,  with 
proper  care,  they  sustain  injury  by  excess  of  it. 


LI. -A   NEW    AND     IMPROVED   METHOD    OF   CULTIVATING  THE    MELON. 

{Read  before  the  HORTICULTURAL  SOCIETY,  November  \btht  1822.] 

I  HAVE  described,  in  a  preceding  paper*,  a  new  kind  of  hot-bed,  into 
which,  by  means  of  a  hollow  wall,  a  heated  current  of  air  is  made  at  all 
times  to  enter,  without  any  mixture  of  the  vapour  arising  from  the  fer- 
menting material ;  and  in  which  the  temperature  is  raised  and  supported 
by  a  rapid  change  of  air,  instead  of  being  lowered,  as  it  is  in  every  other 
kind  of  hot-bed  with  which  I  am  acquainted. 

My  object  in  the  construction  of  this  hot-bed,  was  the  culture  of  the 
pine-apple  ;  but  I  employed  it  in  the  last  summer  in  raising  melons  ;  and 
I  succeeded  so  much  more  perfectly  than  I  had  ever  previously  done, 
that  I  am  led  to  hope  the  following  account  of  the  mode  of  culture 
adopted,  will  be  honoured  by  the  approbation  of  the  Horticultural 
Society. 

Before  I  began  to  raise  my  melon  plants,  I  calculated,  as  I  think  every 
gardener  ought  to  do,  who  cultivates  this  fruit,  the  amount  in  weight 
which  I  might  expect  to  obtain  in  perfection,  from  a  given  extent  of 
glass  roof.     The  heaviest  crop  of  good  grapes,  which  I  had  ever  seen 
growing  in  a  forcing-house,  did  not  appear  to  me  to  exceed  a  pound  to 
every  fifteen  inches  square  of  glass  roof,  taking  into  the  admeasurement 
every  part  of  such  roof.      The  vines  had,  in  such  cases,  lived  through 
many  successive  seasons,  and  possessed  a  large   extent   of  roots   and 
branches,  everywhere  amply  stored  with  the  true  sap,  or  living  blood,  of 
the  plant  generated  in  a  preceding  season,  and  possessing  powers  rela- 
tive to  vegetable  life  analogous  to  those  of  the  blood  of  torpid  animals. 
Their  blossoms  and  minute  leaves  had  also  been  the  product  of  the  labour 
of  a  past  season.     The  melon  plants  had,  on  the  contrary,  everything  to 
accomplish,  not  only  in  a  single  season,  but  in  a  small  part  of  such  sea- 
son ;  and  therefore  I  considered  a  pound  of  fruit  to  every  fifteen  inches 
of  glass  roof,  to  be  the  largest  amount  of  perfect  fruit  upon  which  I  could 

*  See  above,  page  262. 


268  ON    AN    IMPROVED    MODE    OF    CULTIVATING    THE    MELON. 

venture  to  calculate.  The  variety  of  melon,  which  I  proposed  to  culti- 
vate, was  a  Persian  kind,  chiefly  grown  in  the  vicinity  of  Ispahan,  whence 
it  takes  its  name.  Its  form  is  nearly  that  of  a  cucumber,  acquiring 
frequently  more  than  a  foot  in  length,  and  weighing  about  seven  pounds. 
It  possesses,  in  my  estimation,  very  great  excellence  as  a  fruit ;  but  it  is 
of  very  difficult  culture,  the  blossoms  not  setting  freely,  and  the  fruit, 
on  account  of  the  excessive  thinness  of  its  skin,  being  very  subject  to 
decay  prematurely  in  the  damp  atmosphere  of  an  ordinary  hot-bed  :  and 
I  had,  on  these  accounts,  for  some  years  wholly  ceased  to  cultivate  it. 

Having  already  described,  with  sufficient  minuteness,  the  mode  of  con- 
struction and  plan  of  my  hot-bed,  I  need  not,  at  present,  do  anything 
more  than  describe  the  manner  in  which  my  plants  were  managed  in  the 
last  season  ;  they  were  not  planted  till  late  in  the  spring,  and  therefore 
did  not  produce  blossoms  capable  of  affording  fruit  till  the  second  week 
in  July ;  and  it  had  consequently,  in  the  last  season,  to  grow  and  ripen 
under  a  very  cloudy  sky.  Each  plant  was  placed  by  itself  in  a  pot  of 
about  eighteen  inches  in  diameter  in  its  widest  part,  and  of  about  a  foot 
deep,  inside  measure,  the  mould  in  them  being  very  rich  and  light,  and 
constantly  kept  sufficiently  moist  with  manured  water  ;  and  the  number 
of  pots  was  equal  to  the  number  of  melons,  which  I  proposed  that  my 
hot-bed  should  contain  at  one  time.  These  pots  were  supported  at  the 
south  and  lowest  side  of  the  bed  about  fourteen  inches  below  the  glass 
roof;  and  the  plants  were  trained  upon  a  trellis  at  the  same  distance 
from  the  roof,  and  parallel  to  it.  By  these  means,  and  by  giving  to  each 
plant  a  similar  extent  of  space,  I  expected  to  see  each  melon  swell,  and 
be  equally  well  fed  and  ripened  ;  and  I  calculated  upon  the  further 
advantages  of  being  able  to  give  or  to  withhold  water  from  each  plant 
according  to  the  state  of  growth,  or  approaching  maturity  of  its  fruit ; 
and  also  upon  that  of  being  able  to  introduce  other  pots  and  plants,  as 
soon  as  I  had  gathered  the  produce  of  each  plant.  My  success  in  every 
respect  wholly  exceeded  my  expectations,  the  bed  proving  an  instrument 
of  much  greater  powers  than  I  had  calculated  upon  ;  and  I  was  assured 
by  Sir  Harford  Jones,  who  first  supplied  me  with  seeds  of  the  variety, 
(which  he  had  brought  from  Persia,)  that  he  had  never  seen  plants  of 
more  healthy  growth,  nor  with  fruit  better  swelled,  even  in  its  native 
climate.  The  only  enemy  with  which  the  gardener  will,  I  believe,  have 
to  contend,  is  the  red  spider ;  and  against  the  attacks  of  this  he  must 
guard  his  plants,  by  frequently  sprinkling  their  leaves  lightly  with  clear 
warm  water. 

I  had  a  singular  opportunity  in  this  experiment  of  obtaining  evidence 


OX    AN    IMPROVED    MODE    OF    CULTIVATING    THE    MELON.  269 

of  the  truth  of  an  opinion,  which  I  gave  many  years  ago*,  that  every  leaf, 
even  the  most  distant,  of  a  melon-plant,  contributes  to  feed  its  fruit.  One 
of  my  plants  exhibited  appearances  which  led  me  to  conclude  that  a  fruit 
was  set,  and  was  swelling  rapidly  upon  it.  My  gardener,  on  the  contrary, 
was  very  positive  that  no  such  fruit  existed  ;  and  having  myself  searched 
in  vain  to  find  it,  I  was  compelled  to  relinquish  my  opinion  ;  this  however 
I  resumed  upon  observing  the  habit  of  the  plant  two  days  afterwards, 
when  I  ordered  the  lights  to  be  taken  off,  and  every  branch  to  be  minutely 
examined.  It  was  then  discovered,  that  a  melon,  at  the  extremity  of  a 
straggling  branch,  had  fallen  through  the  trellis,  and  was  hanging  half  a 
yard  below  it.  In  this  situation,  it  had  been  entirely  shaded  by  the 
crowded  foliage  of  another  plant ;  but  nevertheless  it  had  grown  in  less 
than  fourteen  days  to  be  nearly  a  foot  long,  and  it  weighed  at  least  four 
pounds.  That  it  had  derived  the  material  necessary  to  its  rapid  growth 
from  the  sap  of  the  parent  plant  cannot,  I  think,  be  doubted :  and  the 
evidence  that  the  most  distant  part  of  the  plant  contributed  to  feed 
it,  is  certainly  extremely  strong ;  for  the  fruit  grew  at  the  distance  of 
at  least  six  feet  from  those  parts  of  the  plant  which  led  me  to  infer  its 
existence. 

By  what  means  the  sap  generated  in  the  distant  foliage  was  carried 
to  this  fruit  in  sufficient  quantity,  is  a  very  interesting  question  to  the 
physiologist,  and  not  less  so  to  the  scientific  gardener. 

I  have  at  different  periods  made  an  immense  variety  of  experiments  to 
ascertain  by  what  organs,  and  under  what  circumstances,  the  lifeless 
inorganic  matter,  which  is  absorbed  by  the  roots  of  plants,  becomes  con- 
verted into  their  true  sap,  or  living  vegetable  blood  ;  and  the  result  of 
every  experiment  has  led  me  to  believe,  that  in  all  cases  where  plants 
possess  leaves,  as  distinct  organs,  it  is  in  such  organs  alone,  and  under 
the  influence  of  light,  that  this  process  takes  place.  The  powers  which 
roots  of  various  forms  and  cuttings,  and  other  detached  parts  of  plants, 
possess  of  emitting  foliage  have  appeared  to  me  to  be  wholly,  in  all  cases, 
dependent  upon  the  presence  of  true  sap  previously  deposited  within 
them.  Like  the  cotyledons  of  seeds,  they  appear  to  be  reservoirs  only, 
which  contain,  but  never  create  :  and  it  has  been  long  ascertained  that 
seedling  plants  perish,  or  at  best  scarcely  retain  life,  if  deprived  of  their 
cotyledons,  even  after  the  radicle  has  penetrated  deeply  into  the  soil,  and 
the  elongated  plumule  has  reached  its  surface  ;  a  discovery  which  appears 
to  be  universally  given  to  Bonnet,  but  which  belongs  to  Malpighi. 

The  following  experiment,  with  many  others  which  I  could  adduce, 

*  See  above,  n.  xxi.  p.  189,  191. 


270        ON  AN  IMPROVED  MODE  OF  CULTIVATING  THE  MELON. 

appears  to  prove  that  powers  have  been  given  to  the  mature  leaf,  which 
have  been  denied  to  the  roots  and  branches  of  plants,  and  to  the  cotyle- 
dons of  their  seeds,  unless  the  latter  expand  into  and  assume,  as  they  in 
many  cases  do,  the  form  and  office  of  leaves.  In  an  early  part  of  the 
summer  some  leaves  of  mint,  (Mentha  piperita,)  without  any  portion  of 
the  substance  of  the  stems  upon  which  they  had  grown,  were  planted  in 
small  pots,  and  subjected  to  artificial  heat,  under  glass.  They  emitted 
roots  and  lived  more  than  twelve  months,  having  assumed  nearly  the 
character  of  the  leaves  of  evergreen  trees  :  and  upon  the  mould  being 
turned  out  of  the  pots,  it  was  found  to  be  everywhere  surrounded  by  just 
such  an  interwoven  mass  of  roots,  as  would  have  been  emitted  by  perfect 
plants  of  the  same  species.  These  roots  presented  the  usual  character  of 
those  organs,  and  consisted  of  medulla,  alburnum,  bark,  and  epidermis  ; 
and  as  the  leaf  itself,  during  the  growth  of  these,  increased  greatly  in 
weight,  the  evidence  that  it  generated  the  true  sap,  which  was  expended 
in  their  formation,  appears  perfectly  conclusive. 

Supposing  the  leaves  of  the  melon  plant  to  possess  (as  I  do  not  enter- 
tain a  shadow  of  doubt  that  they  do)  powers  similar  to  those  of  the  mint 
above  mentioned,  and  of  other  plants,  and  that  all  the  foliage  may  be 
made  to  contribute  to  feed  a  single  fruit,  it  is  not  easy  to  conceive  by 
what  means  this  can  be  done,  without  the  circulation  of  a  very  large 
portion  of  the  true  sap  of  the  plant  (even  of  that  generated  in  its  most 
distant  foliage)  through  such  single  fruit,  be  assumed.  And  it  appears 
difficult  upon  any  other  grounds  to  account  for  the  extremely  rapid 
growth  which,  under  such  circumstances,  takes  place  in  a  single  fruit, 
with  the  influence  of  the  fruit  upon  the  most  distant  parts  of  the  plant, 
and  the  dependence  of  the  ultimate  weight  and  perfection  of  the  fruit 
upon  the  extent  of  the  foliage  of  the  plant.  In  an  experiment  which  I 
made  some  years  ago,  a  single  melon,  of  the  Rock  Canteloup  variety, 
grew  upon  a  plant  which  occupied  more  than  thirty  feet  of  the  surface  of 
a  hot-bed,  but  under  green  glass  of  ordinary  quality ;  where  it  acquired 
the  weight  of  thirteen  and  a  half  pounds,  having  during  its  growth  given 
the  whole  plant  full  employment,  and  apparently  put  the  services  of 
every  leaf  in  requisition,  though  some  of  them  grew  at  nearly  six  feet 
distance  from  it. 

The  disadvantages  of  leaving  too  numerous  a  crop  on  any  plant  are 
sufficiently  well  known,and  every  skilful  gardener  is  able  to  calculate, 
from  the  extent  and  vigour  of  his  melon-plants,  what  number  of  fruits,  of 
any  given  variety,  each  plant  is  capable  of  supporting ;  but  when  a 
melon-plant  has  many  fruits  to  support,  it  is  often  a  partial  parent, 


ON    AN    IMPROVED    MODE    OF    CULTIVATING    THE    MELON.  271 

by  which  one  offspring  is  very  abundantly  fed  whilst  another  starves  ; 
and  hence  often  arises  the  great  disparity  in  the  quality  of  fruit  of  the 
same  plant. 

This  cannot  occur  when  each  plant  has  a  single  fruit  only  to  support, 
and  is  given  a  sufficient  extent  of  foliage ;  and,  under  this  mode  of  culture, 
the  most  shy  and  the  most  free  bearer  become  equally  productive ;  for 
every  plant  will  readily  offer  all  that  is  wanted — a  single  fruit. 

I  have  already  stated  that  I  think  a  melon-plant  of  any  saccharine 
variety  will  require  about  fifteen  inches  square  of  glass  roof  for  every 
pound  of  fruit ;  and  in  this  calculation  I  include  glass  of  good  quality. 
There  may  possibly  be  varieties  of  the  melon  which  will  afford  a  larger 
produce  than  that  above-mentioned ;  but  whatever  variety  be  cultivated, 
I  feel  confident  that  quite  as  large  a  produce  may  be  obtained  by  the 
mode  of  culture  above  recommended  as  by  any  other ;  and  I  cannot  but 
believe  a  larger  produce  of  good  fruit,  owing  to  the  advantages  of  a 
constant  supply  of  warm  air,  and  the  power  of  giving,  and  of  perma- 
nently maintaining,  in  the  bed  a  high  and  regular  temperature,  without 
the  introduction  of  steam,  and  the  power  of  securing  to  each  fruit  its  due 
share  of  nutriment.  I  am  also  of  opinion  that  great  advantages  might 
be  thus  obtained  in  the  very  early  culture  of  the  cucumber.  The  cavity 
of  the  bed  might  be  filled  with  leaves,  or  other  material  which  would 
afford  a  temperate  and  permanent  heat ;  whilst  a  current  of  warm  and 
dry  air  would  be  made  to  flow  constantly  into  the  bed  above  the  level  of 
the  mould  in  which  the  plants  were  placed.  When  the  bed  is  intended 
for  this  purpose,  the  perforations  through  the  bricks  should  be  confined 
to  those  which  stand  above  the  level  of  the  mould. 

As  soon  as  the  crop  of  melons  in  my  bed  was  expended,  the  pots  were 
removed,  and  others  of  smaller  size,  and  containing  pine-apple  plants, 
were  introduced  and  supported  upon  a  frame  of  wood  at  proper  distance 
from  the  glass,  a  new  lining  being  at  the  same  time  given  to  the  bed. 
These  plants  have  subsequently  thriven  exceedingly,  and  I  entertain  no 
doubt  of  their  continuing  to  thrive  through  the  winter;  for  the  powers 
of  a  constant,  though  small,  current  of  heated  air  to  sustain  a  high 
temperature  are  very  great,  operating  not  only  by  introducing  heat,  but 
also  in  opposing  the  ingress  of  the  cold  external  air, — a  circumstance  to 
which  I  particularly  wish  to  attract  the  attention  of  the  gardener. 

I  will  take  this  opportunity  of  suggesting  an  improvement  in  the  con- 
struction of  the  common  pine-stove.  If  the  wall  which  surrounds  the  bark- 
bed  were  made  hollow,  and  its  cavity  given  a  communication  beneath  the 
soil  (as  in  the  hot-bed  I  have  described),  at  its  lower  corners,  with  the 


272  ON    AN    IMPROVED    MODE    OP    CULTIVATING    THE    MELON. 

external  air ;  that  would  pass  into  the  cavity  of  the  wall,  and  escape  into 
the  house  through  passages  immediately  beneath  the  coping  of  such  walls  ; 
and  warm  air  might  be  thus  at  all  times  freely  introduced  with  much 
advantage  to  the  plants,  and  in  winter  with  a  very  considerable  diminution 
of  the  expenditure  of  fuel ;  and  indeed  I  feel  perfectly  confident  that,  by 
the  proper  application  of  hollow  walls  in  a  shed  behind  a  hot-house,  every 
kind  of  forcing  culture  might  be  successfully  carried  on  without  the  use 
of  a  particle  of  fuel,  and  with  a  moderate  quantity  only  of  bark,  or  leaves, 
or  other  fermenting  material. 


LII.— AN    ACCOUNT   OF    THE    INJURIOUS    INFLUENCE    OF   THE   PLUM- 
STOCK   UPON    THE   MOORPARK  APRICOT. 

[Read  before  the  HORTICULTURAL  SOCIETY,  April  }st,  1823.] 

IN  the  selection  of  stocks  for  the  reception  of  grafts  or  buds  of  different 
species  of  fruit-trees,  the  English  gardeners  and  nurserymen  generally 
suppose  that,  when  a  stock  is  employed  upon  which  the  inserted  graft,  or 
bud,  will  grow  freely  and  permanently,  everything  which  is  expedient  or 
beneficial  is  done.  It  is  even  supposed  that  cases  exist  in  which  much 
advantage  is  obtained  by  the  use  of  a  stock  of  a  different  species,  and 
even  of  a  different  genus.  The  peach  and  nectarine  trees  are  thus 
generally  believed  to  succeed  better  upon  the  plum  than  upon  the  native 
stock ;  and  some  varieties  of  the  pear  have  been  pronounced  by  Miller 
to  acquire  their  highest  state  of  perfection  upon  quince-stocks ;  but  I 
suspect  that  Miller  formed  his  opinion  rather  upon  the  external  colour 
and  size  of  the  fruit  than  upon  its  intrinsic  qualities,  and  decided,  as 
every  gardener  who  had  honestly  sent  the  best  produce  of  his  garden  to 
his  employer's  table  would  probably  have  done,  that  the  sample  of  his 
fruit  which  exhibited  the  finest  colour  and  the  largest  size  was  the  best ; 
and  it  is  well  known  that  a  young  pear-tree,  when  growing  upon  a 
quince-stock,  affords  fruit  of  brighter  colours,  and,  in  some  varieties,  of 
larger  size  ;  and  that  the  tree  is  rendered  more  governable,  and  therefore 
more  productive,  when  trained  to  a  wall.  Taking  off  a  circular  ring  of 
bark,  or  what  is  called  ringing  the  stock,  gives  a  similar  increase  of  size 
to  the  fruit,  and  of  brilliancy  to  its  colour  ;  but  its  pulp  is  rendered  much 
less  succulent  and  melting ;  and  I  suspect  that  the  effects  of  a  quince- 
stock,  and  of  ringing,  will  be  found  very  nearly  similar, — each  operating 


INFLUENCE    OF    THE    PLUM-STOCK    ON    THE    APRICOT.  273 

to  interrupt  the  free  and  proper  course  of  the  sap.  Some  varieties  of 
pears  are  known  to  be  spoiled  by  the  quince-stock;  and  I  entertain 
little  doubt  but  that  the  quality  of  every  species  of  fruit,  to  some  extent, 
suffers  when  grown  upon  a  stock  of  another  species  or  genus. 

I  have  been  led  to  these  conclusions  by  the  following  circumstances, 
which  have  within  the  last  two  years  come  under  my  observation.  I 
have  stated,  in  a  former  communication,  that  the  Moorpark  apricot 
succeeds  much  better  upon  its  native  stock  than  upon  a  plum-stock.  I 
had  observed  that  its  foliage  acquired  a  deeper  shade  of  colour,  and  that 
it  retained  its  verdure  very  considerably  later  in  the  autumn ;  and  its 
fruit  appeared  to  me  to  be  singularly  excellent.  I  had  not,  however,  at 
that  period  an  apricot-tree  growing  upon  a  plum-stock,  upon  quite  the 
same  aspect ;  and  I  therefore  hesitated  to  ascribe  the  superiority  of  the 
fruit  to  any  operation  of  the  native  stock.  But  I  have  subsequently 
planted  two  trees,  growing  upon  plum-stocks,  and  two  upon  apricot- 
stocks,  upon  the  same  aspects,  and  in  a  similar  soil ;  giving  those  upon 
the  plum-stocks  the  advantage  of  some  superiority  in  age,  and  I  have 
found  the  produce  of  the  apricot-stocks  to  be  in  every  respect  greatly  the 
best.  It  is  much  more  succulent  and  melting,  and  differs  so  widely  from 
the  fruit  of  the  other  trees,  that  I  have  heard  many  gardeners,  who  were 
not  acquainted  with  the  circumstances  under  which  the  fruit  was  produced, 
contend  against  the  identity  of  the  variety.  The  buds  were,  however, 
taken  from  the  same  tree. 

I  have  also  some  reasons  for  believing  that  the  quality  of  the  fruit  of 
the  peach-tree  is,  in  some  cases  at  least,  much  deteriorated  by  the 
operation  of  the  plum-stock.  My  garden  contains  two  peach-trees  of  the 
same  variety,  the  Acton  Scott,  one  growing  upon  its  native  stock,  and 
the  other  upon  a  plum-stock, — the  soil  being  similar,  and  the  aspect  the 
same.  That  growing  upon  the  plum-stock  affords  fruit  of  a  larger  size, 
and  its  colour,  where  it  is  exposed  to  the  sun,  is  much  more  red  ;  but  its 
pulp  is  more  coarse,  and  its  taste  and  flavour  so  inferior,  that  I  should 
be  much  disposed  to  deny  the  identity  of  the  variety,  if  I  had  not  inserted 
the  buds  from  which  both  sprang  with  my  own  hand. 

Having  tried  experiments  only  in  one  soil,  and  in  the  same  situation, 
I,  of  course,  have  stated  the  foregoing  circumstance  chiefly  with  the  view 
of  exciting  other  horticulturists  to  make  similar  experiments ;  and  it  is 
particularly  desirable  that  such  should  be  tried  in  the  garden  of  the 
Society. 

I  think  it  probable  that  the  quality  of  the  nectarine  will  be  still  more 


274  INFLUENCE    OF    THE    PLUM-STOCK    ON    THE    APRICOT. 

affected,  its  pulp  being  less  succulent  than  that  of  the  peach ;  but  I  have 
not  at  present  any  facts  worth  adducing  in  support  of  this  opinion. 

One  valid  objection  to  the  use  of  peach-stocks  must  be  admitted :  trees 
budded  upon  them  certainly  cannot  be  transplanted  with  an  equal 
certainty  of  success  ;  and  particularly  trained  trees  :  but  those  I  am  very 
much  disposed  to  call  spoiled  trees,  which  appear  calculated  to  gratify 
the  impatience  of  the  planter,  but  which  often  ultimately  disappoint  his 
hopes.  I  have  never  found  any  difficulty  in  transplanting  young  budded 
peach  trees  with  perfect  success. 

The  peach  stones,  having  been  protected  from  severe  frost  through  the 
winter,  may  be  planted  in  drills,  at  about  eight  inches  distant  from  each 
other,  and  a  space  of  about  two  feet  was  left  between  the  rows.  The 
plants  will  spring  up  in  April,  and  in  August  and  September  will  be  of 
proper  age  and  size  to  be  budded  about  two  inches  from  the  ground. 
The  nurseryman  therefore  will  have  the  advantage  of  taking  his  buds 
from  the  trees  whilst  the  fruit  is  upon  them,  and  he  can  in  consequence 
easily  guard  against  errors,  which  much  too  frequently  occur ;  and  he 
may  be  quite  certain  that  none  of  his  buds  will  break  prematurely 
Buds  may  be  inserted  in  the  early  part  of  October;  and  in  the  last 
autumn,  I  introduced  some  with  perfect  success  in  November.  Late  in 
the  autumn,  I  generally  shorten  the  roots  of  my  young  peach-stocks, 
particularly  those  roots  which  descend  perpendicularly  into  the  soil,  by 
introducing  a  spade  into  the  ground  on  two  sides  of  each  plant,  but 
without  moving  it,  or  further  disturbing  its  roots.  Thus  managed,  the 
buds  shoot  very  freely;  and  with  proper  attention  to  preserve  their 
fibrous  roots,  and  to  pack  them  properly,  they  may,  I  am  certain,  be  sent 
to  the  most  distant  parts  of  the  island  without  danger  of  their  being 
killed  by  their  removal.  Older  trees  possibly  cannot  be  removed  without 
danger  of  their  failing;  but  I  transplanted  a  peach  tree  in  the  last 
autumn  of  ten  years  old,  which  grows  upon  its  own  roots,  and  was  more 
than  ten  feet  high  ;  and  it  is  this  spring  emitting  its  blossoms  as  freely  as 
those  trees  which  have  not  been  transplanted.  Its  roots  were,  however, 
well  preserved,  and  its  branches  properly  retrenched. 

Peach  and  nectarine  trees,  particularly  of  those  varieties  which  have 
been  recently  obtained  from  seed,  may  be  propagated  readily  by  layers, 
either  of  the  summer  or  older  wood ;  and  even  from  cuttings,  without 
artificial  heat ;  for  such  strike  root  freely.  But  the  most  eligible  method 
appears  to  be  that  of  sowing  the  stones,  and  budding  the  young  plants  in 
the  same  season ;  and  I  will  venture  to  assert,  that  peach  and  nectarine 
trees  may  be  thus  raised  with  much  less  expense  and  trouble,  than  by  the 


INFLUENCE    OF    THE    PLUM-STOCK    ON    THE    APRICOT.  275 

ordinary  method  of  budding  upon  plum-stocks ;  and  that  the  rapidity  of 
their  growth  will  amply  compensate  for  the  small  size  at  which  it  will  be 
expedient  to  plant  them.  An  opinion  prevails  amongst  gardeners,  that 
such  trees  will  prove  very  short-lived ;  in  opposition  to  this,  I  have 
nothing  further  to  say,  than  that  I  have  plants  of  more  than  twelve  years 
old,  one  of  fourteen  years  old,  which  certainly  show  no  disposition  to  die, 
nor  any  appearance  of  having  grown  old. 


LIII.— AN   ACCOUNT    OF   SOME    MULE    PLANTS. 

[Read  before   the  HORTICULTURAL   SOCIETY,    May   6th,    1823.] 

THE  excessive  rarity  of  mule  plants  in  a  perfectly  wild  state  (if  in  such 
they  exist  at  all),  and  the  facility  with  which  they  are  in  many  cases 
obtained  in  the  garden,  seem  to  countenance  the  opinion  which  is  enter- 
tained by  many  botanists,  that  plants  of  different  species  do  not  readily 
breed  with  each  other,  till  their  natural  habits  have  been  broken  and 
changed  by  the  operation  of  culture  through  some  successive  generations. 
Vegetable  mules  are,  however,  never  produced  except  under  circumstances 
which  rarely,  if  ever,  occur  in  a  perfectly  natural  state ;  for  experiment 
has  satisfied  me,  that  not  only  the  pollen  of  the  alien  species  must  be 
introduced  at  the  proper  period,  but  also,  that  the  natural  pollen  must 
be  kept  away  not  only  at  that  precise  period,  but  generally,  for  several 
succeeding  days  afterwards :  also,  and  even  under  the  most  favourable 
circumstances,  I  have  never  succeeded  in  obtaining  mules,  unless  the  plant, 
or  a  considerable  branch  of  a  fruit  tree,  has  been  reduced  to  the  necessity 
of  nourishing  mule  offspring,  or  none.  When  the  later  blossoms  on  a  fruit 
tree  were  suffered  to  remain,  such  branch  either  threw  off  the  fruit  which 
would  have  afforded  mule  plants,  or  the  natural  pollen  was  found  to  have 
been  subsequently  introduced  by  insects  or  winds,  and  to  have  annihilated 
the  operation  of  that  obtained  from  the  plant  of  another  species.  Not 
improbably  some  erroneous  conclusions  may  also  have  been  drawn,  owing 
to  varieties  of  permanent  habits  into  which  different  species  of  plants 
have  sported,  under  the  influence  of  different  soils  and  climates,  in  a 
perfectly  natural  state,  having  been  mistaken  for  originally  distinct 
species;  for  1  perfectly  agree  with  Mr.  Herbert*,  in  thinking  that  the 
number  of  species  of  plants,  which  came  immediately  from  the  hand  of 

*  Horticultural  Transactions,  Vol.  IV.  page  16. 

T2 


276  ACCOUNT    OF    SOME    MULE    PLANTS. 

nature,  is  probably  much  smaller  than  that  now  found  in  the  catalogues 
of  botanical  writers  :  and  it  is  also  wholly  impossible  to  distinguish  such 
natural  varieties  from  originally  distinct  species,  by  any  peculiarities  in 
their  external  character.  In  the  present  imperfect  and  limited  state 
of  our  information,  it  is  therefore,  in  many  cases,  difficult  to  decide 
whether  plants  are  or  are  not  mules ;  it  being  still  questionable  whether 
mere  natural  varieties,  after  they  have  through  successive  generations 
assumed  very  widely  different  forms  and  characters,  are  found  to  breed 
with  each  other  as  readily  as  other  varieties  of  the  same  species,  of 
similar  habits  ;  and  that  real  mule  plants  have,  in  some  instances,  and 
under  certain  circumstances,  produced  offspring,  (mules  like  themselves, 
I  suspect,)  cannot,  I  believe,  be  questioned. 

The  principal  object  of  the  present  communication  is  to  describe  two 
new  kinds  of  mule  plants,  which  have  recently  come  within  my  observa- 
tion. One  of  these  presents  the  singularity  of  being,  though  certainly  a 
mule,  in  some  degree  deserving  the  attention  of  the  fruit-gardener  ;  and 
the  other  affords  me  the  means  of  pointing  out  a  new  species  of  fruit,  in 
the  Morello  cherry,  to  the  improvement  of  which  I  wish  particularly  to 
invite  the  attention  of  the  experimental  gardener. 

The  results  of  many  experiments  upon  the  different  kinds  of  straw- 
berries which  are  cultivated  in  our  gardens,  led  me,  some  years  ago,  to 
conclude  that  we  possess  three  distinct  species  of  that  genus :  the  wood 
or  Alpine,  the  scarlet  in  many  states  of  variation,  and  the  hautbois.  I 
failed  to  obtain  mule  plants  between  the  Alpine  and  the  scarlet,  and 
hautbois,  which  I  inferred  to  be  of  distinct  species ;  because  they  did  not, 
under  favourable  circumstances,  breed  at  all  with  each  other.  But  I 
have  subsequently  seen,  in  the  possession  of  my  friend  Mr.  Williams  of 
Pitmaston,  mule  plants  obtained  from  the  seeds  both  of  the  scarlet  and 
hautbois,  and  the  pollen  of  the  Alpine  strawberry.  One  of  these,  which 
sprang  from  the  seed  of  the  hautbois,  presents  in  its  foliage  and  habit  the 
character  of  its  female  parent,  without  any  perceptible  variation.  It 
blossoms  very  freely,  and  its  blossoms  set  well ;  but  the  growth  of  the 
fruit  subsequently  remains  very  nearly  stationary  during  the  whole  period 
in  which  the  hautbois  strawberry  grows  and  ripens  ;  after  which  it  swells 
and  acquires  maturity.  It  is  then  rich  and  high-flavoured,  but  of  less 
size  than  the  hautbois,  and  without  seeds.  Mr.  Williams,  however, 
informed  me  that  he  had  once  obtained  a  single  seed,  which  afforded  a 
mule  plant  in  every  respect  similar  to  its  parent.  I  have  sent  a  few 
plants  of  each  kind  to  our  garden,  and  I  believe  the  varieties  will  be 
thought  to  deserve  culture  by  those  who  are  admirers  of  the  flavour  of 


ACCOUNT    OF    SOME    MULE    PLANTS.  277 

the  hautbois,  and  wish  to  prolong  its  season.     The  plants  in  my  garden 
afford  a  second  blossom  in  autumn. 

Not  entertaining  any  doubt  of  the  specific  identity  of  the  Morello  and 
common  cherry,  I  made  experiments  upon  a  large  scale,  confidently 
anticipating  the  production  of  some  very  valuable  new  varieties ;  and  I 
had  in  consequence  not  less  than  twenty  trees,  which  afforded  blossoms  in 
the  last  season.  Buds  of  many  of  these  had  been  inserted  into  the 
bearing  branches  of  old  cherry  trees,  which  were  trained  to  walls  of 
different  aspects ;  and  blossoms,  which  were  all  apparently  well  organized 
and  perfect,  were  everywhere  abundantly  produced,  but  very  nearly  all 
proved  abortive.  From  a  south  wall  I  obtained  five  cherries  from  nearly 
as  many  thousand  blossoms,  and  four  of  these  did  not  contain  seeds. 
One  variety  was  very  large,  and  nearly  similar  in  colour  to  its  male 
parent,  the  Elton  cherry ;  but  its  colour  was  somewhat  deeper.  Its  flesh 
was  white  and  melting,  with  very  abundant  juice ;  but  containing  only  a 
small  portion  of  saccharine  matter.  The  others  were  worthless,  and  all 
the  plants  are,  I  believe,  unquestionably  mules. 

As  a  species  of  fruit,  I  consider  the  Morello  cherry  to  present  very 
strong  claims  to  the  attention  of  the  horticulturist.  The  hardiness  of  its 
blossoms,  which  I  have  found  to  be  alike  patient  of  heat  and  cold ;  the 
large  size  of  the  fruit,  with  its  abundant  juice,  and  power  of  retaining  its 
soundness  and  perfection  long  after  it  has  become  mature;  and  the 
exuberant  produce  of  the  tree  in  situations  where  the  common  cherry 
succeeds  but  ill,  render  it,  with  all  its  present  imperfections,  most 
valuable :  and  there  appears  to  be  no  reasonable  ground  for  doubt,  but 
that  richer  and  possibly  larger  varieties  of  it  may  be  generated  by  proper 
culture  through  a  few  successive  generations.  Should  the  fruit  become 
rich,  a  less  exuberant  produce  must  however  be  expected ;  for  sugar 
appears  to  be  an  article,  the  production  of  which  requires  a  large  expen- 
diture of  the  vital  juices  of  the  tree. 

We  possess,  I  believe,  in  the  Flemish  and  Kentish  cherry,  two 
varieties  of  the  same  species  with  the  Morello ;  and  the  Toussaint,  and 
one  or  two  others  described  by  Duhamel  in  his  Traite  des  Arbres 
Fruitiers,  appear  to  belong  to  the  same  family.  The  Morello  cherry-tree 
is  obviously  the  "  Cerisier  tres-fertile"  of  this  author. 

I  have  seen  the  blossoms  and  fruit  of  the  Morello  cherry-tree  bear,  in 
the  forcing-house,  the  temperature  of  seventy  and  even  of  eighty  degrees, 
without  any  injurious  or  peculiar  effects,  except  that  the  plumules  of  the 
seeds  produced  in  such  high  temperature  expanded  with  something  very 
like  blossoms  upon  the  points.  Small  white  leaves,  in  every  respect 


278  ACCOUNT    OF    SOME    MULBJ   PLANTS. 

similar  to  the  petals  of  blossoms,  were  in  many  instances  arranged  as  in  a 
perfect  blossom,  which  withered  and  died,  whilst  a  bud  upon  the  lower 
part  of  the  stem  vegetated,  and  the  period  of  puberty  in  the  plants  did 
not  subsequently  appear  to  be  at  all  accelerated  by  the  operation  of  the 
high  temperature  in  which  the  seeds  had  been  ripened. 

I  do  not  offer  plants  of  the  mule  varieties  above-mentioned  of  the 
cherry  to  the  Society,  because  I  feel  quite  confident  of  their  being  wholly 
useless. 


LIV.— SOME  REMARKS  ON  THE  SUPPOSED  INFLUENCE  OF  THE  POLLEN, 
IN  CROSS  BREEDING,  UPON  THE  COLOUR  OF  THE  SEED-COATS 
OF  PLANTS,  AND  THE  QUALITIES  OF  THEIR  FRUITS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  June  3e?,  1823.] 

IT  has  been  long  ago  ascertained  by  physiologists,  that  the  seed-coats, 
or  membranes  which  cover  the  cotyledons  of  the  seeds  of  plants,  with 
the  receptacles  which  contain  such  seed-coats,  are  visible  some  time 
before  the  blossoms  acquire  their  full  growth  ;  and  the  existence  of  these 
organs  is,  therefore,  obviously  independent  of  the  influence  of  the  pollen 
upon  the  growth  of  the  internal  and  essential  parts  of  the  future  seeds. 
The  seed-coats  also,  and  the  fruit  of  some  species  of  plants,  acquire 
nearly,  if  not  wholly,  their  perfect  growth  when  the  pollen  has  been 
entirely  withheld,  or  when,  from  other  causes,  it  has  not  operated ;  and 
from  these  circumstances,  and  other  observations,  it  has  been  inferred, 
that  neither  the  external  cover  of  the  seeds,  nor  the  form,  taste,  or 
flavour  of  fruits,  are  affected  by  the  influence  of  the  pollen  of  a  plant 
of  a  different  variety  or  species.  There  exists,  however,  some  difference 
of  opinion  upon  these  points;  and  the  experiments  of  Mr.  Goss  upon  the 
pea,  of  which  an  account  is  given  in  a  paper  recently  printed  in  the  Trans- 
actions of  the  Horticultural  Society*,  appear  strongly  to  countenance 
the  opinion,  that  the  colour  of  the  seed-coats,  at  least,  may  be  changed 
by  the  influence  of  the  pollen  of  a  variety  of  a  different  character ;  and 
hence  he  infers,  with  apparent  reason,  the  probability  that  the  taste  and 
flavour  of  fruits  may  be  also  affected. 

The  narrative  of  Mr.  Goss  is  unquestionably  quite  correct;  but  I 
believe  that  there  is  an  error  in  the  inference  which  he  has  drawn  ;  and 
I  am  anxious  that  such  error,  if  it  exist,  should  be  pointed  out ;  because 

*  See  Vol.  V.  page  234. 


ON  THE  SUPPOSED  INFLUENCE  OF  THE  POLLEN.  279 

it  may  occasion  many  experiments  to  be  made  to  prove  that  which  I 
conceive  to  have  been  already  sufficiently  proved  ;  and,  consequently, 
cause  the  useless  expenditure  of  time  and  labour,  which  might  be  advan- 
tageously employed  in  similar  investigations  upon  other  plants  in  the  wide 
and  unexplored  field  which  lies  open  to  the  experimental  Horticulturist. 

The  numerous  varieties  of  strictly  permanent  habits  of  the  pea,  its 
annual  life,  and  the  distinct  character  in  form,  size,  and  colour  of  many 
of  its  varieties,  induced  me,  many  years  ago,  to  select  it  for  the  purpose 
of  ascertaining,  by  a  long  course  of  experiments,  the  effects  of  intro- 
ducing the  pollen  of  one  variety  into  the  prepared  blossoms  of  another. 
My  chief  object  in  these  experiments  was  to  obtain  such  information  as 
would  enable  me  to  calculate  the  probable  effects  of  similar  operations 
upon  other  species  of  plants ;  and  I  believe  it  would  not  be  easy  to 
suggest  an  experiment  of  cross  breeding  upon  this  plant,  of  which  I 
have  not  seen  the  result,  through  many  successive  generations.  I  shall, 
therefore,  proceed  to  give  a  concise  account  of  some  of  these  experi- 
ments, or  rather  (as  I  wish  not  to  occupy  more  than  necessary  of  the 
time  of  the  Society),  to  state  the  results  of  a  few  of  them,  believing 
that  I  shall  be  able  to  explain  satisfactorily  the  cause  of  a  coloured 
variety  of  the  pea  having  been  apparently  changed  into  a  white  variety, 
by  the  immediate  influence  of  the  pollen  in  the  experiment  of  Mr.  Goss. 

When,  in  my  experiments,  the  pollen  of  a  gray  pea  was  introduced 
into  the  prepared  blossoms  of  a  white  variety,  no  change  whatever  took 
place  in  the  form,  or  colour,  or  size  of  the  seeds ;  all  were  white,  and 
externally  quite  similar  to  others  which  had  been  produced  by  the 
unmutilated  blossoms  of  the  same  plant.  But  these  when  sown  in  the 
following  year  uniformly  afforded  plants  with  coloured  leaves  and  stems, 
and  purple  flowers;  and  these  produced  gray  peas  only.  When  the 
stamens  of  the  plants  which  sprang  from  such  gray  peas  were  extracted, 
and  the  pollen  of  a  white  variety,  of  permanent  habits,  was  introduced, 
the  seeds  produced  were  uniformly  gray ;  but  many  of  these  afforded 
plants  with  perfectly  green  leaves  and  stems,  and  with  white  flowers, 
succeeded,  of  course,  by  white  seed.  In  these  experiments,  the  coty- 
ledons of  all  the  varieties  of  peas  employed  or  produced  were  yellow ; 
and,  consequently,  the  peas  with  white  seed-coats  retained  their  ordinary 
colour,  though  they  contained  the  plumules  and  cotyledons  of  coloured 
pea  plants.  The  cotyledons  of  the  blue  Prussian  pea,  which  was  the 
subject  of  Mr.  Goss's  experiments,  are,  on  the  contrary,  blue;  and  the 
colour  of  these  being  perceptible  through  the  semi-transparent  seed- 
coats,  occasioned  those  to  appear  blue,  though  they  are  really  white ; 


280  ON  THE  SUPPOSED  INFLUENCE  OF  THE  POLLEN. 

the  whole  habits  of  that  plant  are  those  of  a  white  pea.  The  colour  of 
the  cotyledons  only  were,  I  therefore  conceive,  changed  ;  whilst  the  seed- 
coats  retained  their  primary  degree  of  whiteness.  I  must  consequently 
venture  to  conclude,  that  the  opinions  of  Mr.  Salisbury,  quoted  by 
Mr.  Goss,  which  have  also  very  long  been  mine,  viz.  that  neither  the 
colour  of  the  seed-coats,  nor  the  form,  taste,  or  flavour  of  fruits,  are 
ever  affected  by  the  immediate  influence  of  the  pojlen  of  a  plant  of 
another  variety  or  species,  are  well-founded. 

I  need  not  add,  that  Mr.  Seton's  experiment  mentioned  in  the  note  to 
Mr.  Goss's  paper,  is  also  most  perfectly  accurate ;  though  the  results 
differed  from  those  obtained  by  Mr.  Goss,  owing,  I  imagine,  to  the 
greater  permanence  of  colour  in  the  cotyledons  of  the  green  Imperial 
pea,  which  was  the  subject  of  his  experiments. 


LV.— ON   THE   PREPARATION    OF    STRAWBERRY    PLANTS    FOR   EARLY 

FORCING. 

[Read  before  the  HORTICULTURAL  SOCIETY,  March  16th,  1824.] 

THE  method  of  preparing  strawberry  plants  for  early  forcing,  by 
putting  the  plants  into  pots  a  year,  or  longer,  before  they  are  intended  to 
afford  fruit,  is  generally  perfectly  successful,  and  is  in  every  respect 
eligible,  except  that  it  requires  a  good  deal  of  time  and  trouble.  For  if 
the  pots  be  not  regularly  watered  during  the  summer  after  the  plants  are 
put  into  them,  the  size  of  the  future  fruit  will  be  considerably  reduced  ; 
and  if  during  the  following  winter  the  pots  be  not  carefully  protected  from 
excess  of  moisture  and  frost,  a  great  part  of  the  fibrous  roots,  which  lie 
in  contact  with  the  internal  surface  of  the  pots,  will  be  found  lifeless  in 
the  spring ;  and  many  of  the  pots,  if  their  quality  be  not  very  good,  will 
be  broken  by  the  expansion  of  the  frozen  water. 

The  minute  fibrous  roots  of  trees  (the  chevelu  of  the  French  writers) 
have  been  pronounced  by  them,  and  by  all  the  naturalists  of  this  country, 
who  have  written  upon  the  subject,  to  be,  like  the  leaves  of  deciduous  plants, 
annual  productions  only  :  and  such  is  the  opinion  of  Duhamel,  or  rather 
his  decision  respecting  facts  within  his  own  observation ;  for  he  rarely,  if 
ever,  favours  his  readers  with  his  opinions.  If  the  fibrous  roots  of  plants, 
which  have,  like  the  strawberry  plant,  the  whole  habits  of  trees,  be 
annual  productions  only;,  any  effort  to  preserve  them  through  the  winter 
must  be  useless  ;  but  I  deny  the  fact  of  their  being  annual  productions 


ON    THE    PROPAGATION    OF    STRAWBERRY    PLANTS.  281 

only  ;  and  I  contend  that  whenever  they  are  found  wholly  lifeless  round 
the  surface  of  the  mould  of  the  pots,  as  they  often  are  after  unfavourable 
winters,  the  growth  and  produce  of  the  plants  in  the  succeeding  season 
will  be  much  diminished. 

The  mode  of  management  which  I  have  adopted,  and  which  it  is  the 
object  of  the  present  communication  to  recommend,  is  the  following. 

I  manure  a  small  piece  of  ground  very  highly,  but  very  superficially, 
just  covering  the  manure  with  mould  ;  thus  deviating  widely  from  my 
ordinary  practice  of  putting  the  manure  deep  in  the  soil  to  occasion  the 
roots  to  descend  deep,  that  they  may  be  enabled  to  supply  proper  moisture 
in  dry  weather.  The  ground  being  prepared,  the  strongest  and  best 
rooted  runners  of  the  preceding  year  are  selected  and  planted  in  rows, 
one  foot  apart,  in  the  beginning  of  March.  The  distance  between  each 
plant  is  eight  inches  in  one  half  the  rows,  and  four  inches  only  in  the 
other  half,  the  thickly  and  thinly  planted  rows  occurring  alternately.  In 
July  all  the  plants  of  the  thickly  planted  rows  are  removed  to  ground 
that  has  produced  an  early  crop  of  peas  or  potatoes ;  and  these,  having 
their  roots  well  preserved,  always  afford  me  an  abundant  crop  of  fruit  in 
the  following  summer.  The  other  plants  remain  unnoticed  till  the  end 
of  November,  when  the  mould  between  the  rows  is  removed  with  the 
spade,  and  the  most  widely  extended  lateral  roots  detached  from  it.  The 
spade  is  also  made  to  pass  under  each  plant,  and  between  it  and  the  next 
adjoining,  so  that  each  plant  becomes  capable  of  being  removed  at  a  sub- 
sequent period  without  having  any  of  its  roots  ruptured  ;  and  the  whole 
of  these  should  be  preserved  as  entire  as  is  practicable.  As  each  plant 
becomes  detached  from  the  surrounding  soil,  the  ground  is  closed  around 
it,  and  it  remains  till  it  is  wanted  ;  but  it  should  be  placed  in  its  pots  as 
early  as  the  middle  of  February,  if  it  be  not  sooner  removed.  At  this 
period  innumerable  radicles  will  be  seen  to  spring  from  the  sides  of  the 
older  roots,  and  these  readily  extend  themselves  into  any  proper  soil  that 
is  placed  in  contact  with  them.  I  always  employ  soil  of  the  richest 
quality,  and  very  finely  reduced  ;  and  a  good  deal  of  water,  holding 
manure  in  solution,  is  employed  to  occasion  the  newly  introduced  soil  to 
occupy  all  space  previously  vacant  in  the  pots.  The  plants  are  then  in  a 
state  to  be  subjected  immediately  to  artificial  heat. 

Having  denied,  in  opposition  to  the  generally  received  opinion,  that 
the  slender  fibrous  roots  of  trees  and  plants,  having  the  habits  of  trees, 
are  of  annual  duration  only  ;  and  the  subject  being  of  much  importance 
to  the  gardener  ;  I  will  state  a  few  facts  in  support  of  my  opinion.  That 
many  of  the  fibrous  roots  usually  perish  in  winter  I  admit ;  but  under 


282  ON    THE    PROPAGATION    OF    STRAWBERRY    PLANTS. 

favourable  circumstances  I  have  seen  a  very  large  portion  perfectly  alive 
and  growing  in  the  spring  ;  and  in  the  last  year  I  tried  the  following 
experiment,  the  evidence  of  which  is,  I  think,  conclusive.  Having 
observed  that  fig-trees  of  some  varieties  are  capable  of  ripening  their  fruit 
in  much  higher  temperature  than  others,  I  thought  it  expedient  to  try 
whether  the  same  variation  of  power  to  bear  different  degrees  of  temper- 
ature did  not  exist  in  varieties  of  other  species  of  fruits.  Young  plants 
of  different  new  varieties  of  nectarines  were  therefore  placed  in  the  stove 
in  the  spring  of  1823,  where  they  grew  well  till  Midsummer,  after  which 
all,  except  one,  indicated,  by  shedding  prematurely  their  full  grown  young 
leaves,  the  presence  of  excess  of  temperature.  One  tree,  whether  owing 
to  any  peculiarity  of  the  constitution  of  the  variety,  or  other  cause, 
remained  in  full  health  till  the  end  of  the  summer ;  when  its  wood  and 
foliage,  having  become  perfectly  mature,  and  the  latter  beginning  to  turn 
yellow  and  fall  off,  it  was  removed,  in  September,  to  the  open  wall.  In 
this  situation  it  remained  till  the  middle  of  December,  its  roots  having 
been  purposely  carefully  guarded  from  injury  either  from  excess  of 
moisture,  or  of  frost.  In  December,  owing  to  the  high  excitability  the 
plant  had  acquired  by  the  treatment  to  which  it  had  been  previously  sub- 
jected, its  buds  showed  much  disposition  to  vegetate ;  and  it  was  conse- 
quently taken  from  the  pot  to  the  situation  it  was  intended  permanently 
to  occupy. 

Supposing  the  minute  fibrous  roots  of  a  plant,  thus  treated,  to  be,  like 
its  leaves,  organs  of  annual  duration  only,  they  ought  in  this  case  to  have 
wholly  ceased  to  live ;  but  on  the  contrary,  I  found  them  all  alive,  and 
all  in  the  act  of  elongating.  The  evidence  in  this,  and  in  many  other  cases, 
of  the  fibrous  roots  continuing  to  live  and  vegetate  in  a  second  season  is 
positive ;  that  of  my  opponents  is  wholly  negative ;  and  a  little  positive 
evidence  in  this,  as  in  all  other  cases,  is  more  than  equivalent  to  a  great 
deal  of  negative  evidence.  I  must  therefore  conclude,  in  opposition  to 
the  opinion  of  those  whom  I  am  much  disposed  to  treat  with  deference, 
that  the  preservation  of  the  minute  fibres  of  plants  is  important ;  and  I 
believe  almost  every  experienced  gardener  will  coincide  with  me. 


283 


LVL— ON  THE   CULTIVATION  OF   STRAWBERRIES. 
[Read  before  the   HORTICULTURAL   SOCIETY,  December  2lst,  1824.] 

MR.  KEENS  has  published,  in  the  Transactions  of  the  Horticultural 
Society*,  some  excellent  observations  upon  the  proper  modes  of  managing 
different  varieties  of  the  strawberry  ;  in  conjunction,  however,  with  some 
opinions  which  I  do  not  think  well  founded  :  and  as  I  rarely  see  in  the 
gardens  of  my  friends  that  which  is,  in  my  opinion,  even  a  moderately 
good  crop  of  strawberries,  I  shall  proceed  to  state  some  conclusions 
which  theory  and  practice  have  conjointly  led  me  to  draw,  relatively 
to  the  most  advantageous  modes  of  culture  of  those  species  and  varieties 
of  fruit. 

I  perfectly  coincide  in  opinion  with  Mr.  Keens,  that  the  spring  is  the 
only  proper  season  for  planting.  At  that  season  of  the  year,  the  ground, 
having  been  properly  worked  and  manured,  will  long  continue  light  and 
permeable  to  the  roots,  which  will  consequently  descend  during  the 
summer  deeply  into  the  soil.  Abundant  foliage  will  be  produced,  which 
will  be  fully  exposed,  through  the  summer,  to  the  light ;  and  much  true 
sap  will  be  generated,  whilst  very  little,  comparatively,  will  be  expended ; 
for  if  any  fruit  stalks  appear,  those  should  be  taken  off.  In  the  following 
season,  as  Mr.  Keens  has  justly  observed,  a  superior  crop  will  be  borne 
than  by  plants  of  greater  age,  or  differently  cultivated. 

When  plantations  of  strawberries  are  made,  as  they  usually  are,  in 
the  month  of  August,  the  plants  acquire  sufficient  strength  before  winter 
to  afford  a  moderate  crop  of  fruit  in  the  following  year :  but  the  plants 
will  not  have  formed  a  sufficient  reservoir  of  true  sap  to  feed  even  such  a 
crop,  without  being  too  much  impoverished  ;  their  spring  foliage  will  be 
also  exhausted  in  feeding  the  fruit,  and  will  continue,  through  the 
summer,  to  shade  the  leaves  subsequently  produced.  The  aggregate 
produce  in  two  seasons  will,  in  consequence,  generally  be  found  to  be  less 
in  quantity,  and  very  inferior  in  quality,  to  that  afforded  in  one  season 
by  a  plantation  of  equal  extent,  made  in  the  spring. 

Mr.  Keens  suffers  his  beds  to  continue  three  years,  though  he  admits 
that  the  produce  of  the  first  year  is  the  most  abundant,  and  of  the  best 
quality ;  and  in  order  to  afford  his  plants  sufficient  space,  when  they  are 
three  years  old,  he  places  them  at  too  great  distances,  in  my  opinion, 
from  each  other,  to  obtain  the  greatest  produce  from  the  smallest  extent 
of  ground.  He  places  his  hautbois  and  pine  strawberry  plants  at  eighteen 

*  Vol.  II.  page  392. 


284  ON    THE    CULTIVATION    OF    STRAWBERRIES. 

inches  apart  in  the  rows,  with  intervals  of  two  feet  between  the  rows ; 
each  square  yard  consequently  contains  three  plants  only.  I  have  placed 
Downton  strawberry  plants,  which  require  as  much  space  as  those  of  the 
hautbois,  or  pine,  in  rows  at  sixteen  inches  distance  from  each  other,  and 
with  only  eight  inches  distance  between  the  plants ;  which  is  nearly  nine 
to  each  square  yard  ;  and  I  have  found  each  plant  at  such  distances 
nearly,  if  not  quite,  as  productive,  as  when  placed  with  much  wider 
intervals.  The  old  scarlet  strawberry  I  have  also  found  to  bear  admirably 
when  plants  have  been  placed  in  rows  of  one  foot  distance  from  each 
other,  with  spaces  of  half  that  distance  between  the  plants ;  and  I  think 
1  have  obtained  more  than  twice  the  amount  of  produce  from  the  same 
extent  of  ground  which  I  should  have  obtained,  if  my  plants  had  been 
placed  at  the  distances  recommended  by  Mr.  Keens.  My  beds  are, 
however,  totally  expended  at  the  end  of  sixteen  or  seventeen  months  from 
the  time  of  their  being  formed,  and  the  ground  is  then  applied  to  other 
purposes.  I  have  consequently  the  trouble  annually  of  planting ;  but  I 
find  this  trouble  much  less  than  that  of  properly  managing  old  beds  ;  and 
I  am  quite  certain  that  I  obtain  a  much  larger  quantity  of  fruit,  and  of 
very  superior  quality,  than  I  ever  did  obtain,  by  retaining  the  same  beds 
in  bearing  during  three  successive  years,  from  the  same  extent  of  ground. 

There  is  a  very  large  strawberry  of  most  luxuriant  growth  raised  from 
seed  by  Mr.  Williams  of  Pitmaston,  called  the  yellow  Chili,  which  will 
alone,  of  those  varieties  which  I  have  cultivated,  require,  in  my  opinion, 
wider  intervals  than  those  I  have  mentioned ;  and  the  distances  recom- 
mended by  Mr.  Keens  will,  I  think,  be  found  expedient,  where  that 
variety  is  cultivated.  It  is  a  variety  of  much  merit,  and  of  most  extra- 
ordinary size,  a  single  fruit,  raised  in  my  garden,  in  the  last  season, 
having  weighed  558  grains.  Some  plants  of  it  were  sent  by  Mr.  Williams 
to  the  Society's  garden  in  the  last  spring. 

I  perfectly  approve  of,  and  have  long  practised,  the  mode  of  manage- 
ment recommended  by  Mr.  Keens,  of  placing  some  long  dung  between 
the  rows,  where  it  has  all  the  good  effects  which  he  ascribes  to  it ;  but 
to  his  practice  of  digging  between  the  rows  I  object  most  strongly  ;  for 
by  shortening  the  lateral  roots  in  autumn,  the  plants  not  only  lose  the 
true  sap,  which  such  roots  abundantly  contain  ;  but  the  organs  them- 
selves, which  the  plants  must  depend  upon  for  supplies  of  new  food  in  the 
spring,  must  be,  to  a  considerable  extent,  destroyed.  This  mode  of 
treating  strawberry-plants  is  much  in  use  amongst  country  gardeners, 
and  I  have  amply  tried  it  myself,  but  always  with  injurious  effects  ;  and 
I  do  not  hesitate  to  pronounce  it  decidedly  bad. 


ON    THE    CULTIVATION    OF    STRAWBERRIES.  285 

The  wide  intervals  recommended  by  Mr.  Keens  certainly  permit  the 
fruit  to  be  gathered  with  much  convenience  ;  but  spaces  to  receive  the 
feet  of  the  gatherers  of  the  fruit  may  be  easily  made ;  and  it  is  much 
better  that  a  small  number  of  strawberries  should  be  destroyed,  than 
that  a  large  quantity  should  fail  to  be  produced,  owing  to  more  than 
necessarily  wide,  void  spaces. 

Taking  off  the  runners  is  not  expedient  in  the  mode  of  culture  I 
recommend,  and,  under  all  circumstances,  this  must  be  done  with 
judgment  and  caution;  for  every  runner  is,  in  its  incipient  state  of 
formation,  capable  of  becoming  a  fruit  stalk,  and  if  too  great  a  number 
of  the  runners  be  taken  off  in  the  summer,  others  will  be  emitted  by 
the  plants,  which  would,  under  other  circumstances,  have  been  trans- 
muted into  fruit  stalks.  The  blossoms,  consequently,  will  not  be  formed 
till  a  later  period  of  the  season,  and  the  fruit  of  the  following  year  will 
thence  be  defective  alike  in  quantity  and  quality :  and,  under  the  mode 
of  culture  recommended,  a  large  part  of  the  runners,  when  these  are 
taken  off  in  the  spring,  will  be  required  to  form  the  new  beds. 

I  have  found  the  alpine  strawberries  to  succeed  best,  when  seedling 
plants,  raised  very  early  in  the  spring,  or  those  obtained  from  runners 
of  the  preceding  year,  have  been  planted  in  the  beginning  of  April,  at 
one  foot  apart,  in  beds  of  about  four  or  five  feet  wide,  with  intervals 
between  the  beds.  It  is  expedient,  in  the  culture  of  these  varieties, 
that  the  superficial  soil  should  be  extremely  rich ;  because  much  the 
most  valuable  part  of  their  produce  is  obtained  from  runners  of  the 
same  season,  and  these  require  to  be  well  nourished.  If  a  good  alpine 
variety  be  planted,  the  blossoms  of  all  the  runners  will  rise  with  the  third 
leaf.  The  best  which  I  have  seen  affords  a  white  fruit,  similar  in  form 
to  the  red  variety ;  and  the  old  plants  of  this,  as  well  as  the  runners, 
continue  to  bear  till  the  blossoms  are  destroyed  by  frost :  and  both  the 
white  wood  and  the  white  alpine  strawberries,  appear  to  me  to  retain 
their  flavour  more  perfectly  in  autumn  than  the  red.  The  habits  of  the 
white  alpine  variety  above-mentioned,  of  which  I  have  sent  plants  to  the 
garden  of  the  Society,  are  permanent  in  the  seedling  plants ;  provided 
the  seed  be  grown  at  some  distance  from  plants  of  the  coloured  varieties 
of  the  same  species. 

Mr.  Keens  supposes  the  alpine  strawberry-plants  to  be  incapable  of 
producing  blossoms  till  they  are  a  year  old;  but  I  have  shown  that  they 
afford  fruit  in  a  very  few  months  after  they  have  sprung  from  seeds. 
He  also  supposes  that  the  seedling  plants  of  other  species  of  strawberries 


286  ON    THE    CULTIVATION    OF    STRAWBERRIES. 

do  not  produce  fruit  till  they  are  two  years  old.  I  entertain  no  doubt 
but  that  he  is  correct,  when  the  plants  are  raised  in  the  open  ground ; 
but  when  I  have  employed,  as  I  have  always  done,  artificial  heat  early 
in  the  spring,  I  have  obtained  abundant  crops  from  yearling  plants  of 
every  species. 


LVIL— UPON   THE    BENEFICIAL    EFFECTS    OF    PROTECTING    THE    STEMS 
OF  FRUIT-TREES  FROM  FROST  IN  EARLY  SPRING. 

[Read  before    the   HORTICULTURAL    SOCIETY,    February   lst>    1825.] 

THE  blossoms  of  fruit  trees  fall  off  abortively  in  some  seasons,  and 
produce  much  fruit  in  others,  in  which  the  weather,  relatively  to  tempera- 
ture and  moisture,  has  been  nearly  the  same  during  the  flowering  season 
of  such  trees  ;  and  it  is  in  very  favourable,  or  very  unfavourable  seasons 
only,  that  the  gardener  can,  with  any  degree  of  precision,  pronounce  what 
portion  of  his  blossoms  will  afford  fruit.  If  a  larger  part  of  it  than  he  has 
been  led  to  anticipate  prove  abortive,  he  generally  attributes  its  falling  off 
to  something  which  he  calls  a  blight,  and  which  he  supposes  to  be  the 
operation  of  some  unknown  noxious  quality  in  the  atmosphere,  during  the 
season  in  which  his  trees  have  been  in  blossom. 

Many  circumstances  have  at  different  periods  come  under  my  observa- 
tion, which  have  led  me  to  draw  a  different  conclusion,  and  to  believe  that 
whenever  a  very  large  portion  of  the  well  organized  blossom  of  fruit  trees 
falls  off  abortively,  in  a  moderately  favourable  season,  the  cause  of  the 
failure  may  generally  be  traced  to  some  previous  check  which  the  motion 
and  operation  of  the  vital  fluid  of  the  tree  has  sustained. 

It  is  well  known  that  the  bark  of  oak  trees  is  usually  stripped  off  in  the 
spring,  and  that  in  the  same  season  the  bark  of  other  trees  may  be  easily 
detached  from  their  alburnum,  or  sap-wood,  from  which  it  is  at  that 
season  separated  by  the  intervention  of  a  mixed  cellular  and  mucilaginous 
substance ;  this  is  apparently  employed  in  the  organization  of  a  new  layer 
of  fibre,  or  inner  bark,  the  annual  formation  of  which  is  essential  to  the 
growth  of  the  tree.  If,  at  this  period,  a  severe  frosty  night,  or  very  cold 
winds  occur,  the  bark  of  the  trunk  or  main  stem  of  the  oak  tree  becomes 
again  firmly  attached  to  its  alburnum,  from  which  it  cannot  be  separated 
till  the  return  of  milder  weather.  Neither  the  health  of  the  tree,  nor  its 
foliage,  nor  its  blossoms,  appear  to  sustain  any  material  injury  by  this 
sudden  suspension  of  its  functions ;  but  the  crop  of  acorns  invariably 


ON    PROTECTING    THE    STEMS    OF    FRUIT-TREES    FROM    FROST.  287 

fails.  The  apple  and  pear  tree  appear  to  be  affected  to  the  same  extent 
by  similar  degrees  of  cold.  Their  blossoms,  like  those  of  the  oak,  often 
unfold  perfectly  well,  and  present  the  most  healthy  and  vigorous  cha- 
racter ;  and  their  pollen  sheds  freely.  Their  fruit  also  appears  to  set 
well ;  but  the  whole,  or  nearly  the  whole,  falls  off  just  at  the  period  when 
its  growth  ought  to  commence.  Some  varieties  of  the  apple  and  pear  are 
much  more  capable  of  bearing  unfavourable  weather  than  others ;  and 
even  the  oak  trees  present  in  this  respect  some  dissimilarity  of  consti- 
tution. 

It  is  near  the  surface  of  the  earth  that  frost  in  the  spring  operates 
most  powerfully ;  and  the  unfolding  buds  of  oak  and  ash  trees,  which  are 
situated  near  the  ground,  are  not  unfrequently  destroyed,  whilst  those  of 
the  more  elevated  branches  escape  injury ;  and  hence  arises,  I  think,  a 
probability  that  some  advantages  may  be  derived  from  protecting  the 
stems  or  larger  branches  of  fruit  trees,  as  far  as  practicable,  from  frost 
in  the  spring ;  and  the  following  facts  appear  strongly  to  support  this 
conclusion. 

Mr.  Williams  of  Pitmaston  pointed  out  to  me,  two  or  three  years 
ago,  an  apple  tree  which,  having  had  its  stem  and  part  of  its  larger 
branches  covered  by  evergreen  trees,  had  borne  a  succession  of  crops  of 
fruit ;  whilst  other  trees  of  the  same  variety,  and  growing  contiguously  in 
the  same  soil,  but  without  having  had  their  stems  protected,  had  been 
wholly  unproductive.  I  subsequently  saw,  in  the  garden  of  another 
of  my  friends,  Mr.  Arkwright  of  Hampton  Court,  in  Herefordshire,  a 
nectarine  tree,  which  having  sprung  up  from  a  seed  accidentally  in  a 
plantation  of  laurels,  had  borne  as  a  standard  tree  three  successive  crops 
of  fruit.  The  possessor  of  it,  with  the  intention  of  promoting  its  growth 
and  health,  cut  away  the  laurel  branches  which  surrounded  its  stems,  in 
the  winter  of  1823-4,  and  in  the  succeeding  season  not  a  single  fruit  was 
produced.  Never  having  known  an  instance  of  a  standard  nectarine  tree 
bearing  fruit  in  a  climate  so  unfavourable,  or  nearly  so  unfavourable,  I 
was  led  to  expect  that  the  variety  possessed  an  extraordinary  degree  of 
hardiness :  but  having  inserted  some  buds  of  it  into  bearing  branches 
upon  the  walls  of  my  garden  at  Downton  in  the  autumn  of  1822,  I  have 
not  had  any  reason  to  believe  that  its  blossoms  are  at  all  more  patient 
of  cold  than  those  of  other  seedling  varieties  of  the  nectarine. 

I  planted  some  years  ago  in  my  garden,  under  a  wall,  in  a  north-east 
aspect,  and  shaded  by  a  contiguous  building,  a  common  Chinese  rose  tree 
(Rosa  indica)  and  a  plant  of  Irish  ivy.  Both  have  risen  considerably 
above  the  top  of  the  wall,  which  is  thirteen  feet  high ;  and  the  rose  tree, 


288  ON    PROTECTING    THE    STEMS    OF    FRUIT-TREES    FROM    FROST. 

of  which  the  stem  is  wholly  covered  by  the  branches  and  foliage  of  the 
ivy,  has  annually  produced  more  abundant  flowers,  and  exhibited  symp- 
toms of  more  luxuriant  health,  than  any  other  tree  of  the  same  kind  in 
my  possession.  The  soil  in  which  it  grows  is  poor  and  unfavourable ;  and 
I  am  unable  to  discover  any  cause,  except  the  protection  it  receives,  from 
which  it  has  derived  its  luxuriant  health  and  growth. 

Ivy  is  generally,  I  believe,  known  to  gardeners  as  a  creeping  dependent 
plant  only :  but  when  the  trees  have  acquired  a  considerable  age,  and 
have  produced  fruit-bearing  branches,  these  exhibit  an  independent  form 
of  growth,  which  they  retain  when  detached,  and  form  very  hardy  ever- 
green shrubs  of  low  stature.  If  these  were  intermixed  with  plants  of  the 
more  delicate  varieties  of  the  Chinese  rose,  or  other  low  deciduous  and 
somewhat  tender  flowering  shrubs,  so  that  the  stems  of  the  latter  would 
be  covered  in  the  winter,  whilst  their  foliage  would  be  fully  exposed  to 
the  light  in  summer,  I  think  it  probable  that  those  might  be  successfully 
cultivated  in  situations  where  they  would  perish  without  such  protection : 
and  the  evergreen  foliage  of  the  ivy  plants  in  winter  would  be  generally 
thought  ornamental.  Detached  fruit-bearing  branches  of  ivy  readily 
emit  roots,  and  the  requisite  kind  of  plants  would  therefore  be  easily 
obtained. 


LVIIL— AN    ACCOUNT    OF    A    METHOD    OF    OBTAINING   VERY   EARLY 
CROPS    OF   THE    GRAPE   AND    FIG. 

[Read  before  the  HORTICULTURAL  SOCIETY,  March  1st,  1825.] 

MR.  ARKWRIGHT  *  has  proved  that  vines,  of  which  the  wood  and  fruit 
have  ripened  late  in  one  season,  will  vegetate  late  in  the  following  season, 
under  any  given  degree  of  temperature ;  and  I  have  shown  the  converse 
of  this  proposition  to  be  equally  true  t ;  the  plants  under  each  different 
mode  of  treatment  requiring  a  period  of  rest,  during  which  they  regain 
their  expended  excitability.  The  following  statements  will  show  that 
Mr.  Arkwright  and  myself  have  met  at  the  same  point,  like  navigators 
who  have  continued  to  proceed  east  and  west  in  diametrically  opposite 
courses,  the  one  with  an  apparent  loss  and  the  other  with  an  apparent 
gain  of  time. 

A  Verdelho  vine,  growing  in  a  pot,  was  placed  in  the  stove  early  in 
the  spring  of  1823,  where  its  wood  became  perfectly  mature  in  August. 

*  Horticultural  Transactions,  Vol.  III.  page  95.  f  See  above,  p.  228. 


ON  EARLY  CROPS  OF  THE  GRAPE  AND  FIG.  289 

Tt  was  then  taken  from  the  stove  and  placed  under  a  north  wall,  where 
t  remained  till  the  end  of  November,  when  it  was  replaced  in  the  stove ; 
and  it  ripened  its  fruit  early  in  the  following  spring.  In  May  it  was  again 
transferred  to  a  north  wall,  where  it  remained  in  a  quiescent  state  till 
the  end  of  August.  It  then  vegetated  strongly,  and  showed  abundant 
blossom,  which  upon  being  transferred  to  the  stove  set  very  freely ;  and 
the  fruit,  having  been  subjected  to  the  influence  of  a  very  high  temperature, 
ripened  early  in  the  present  month,  February.  The  plant  will  retain  its 
foliage  till  April,  and  will  not  be  prepared  to  vegetate  again  till  late  in  the 
spring,  and  it  is  at  the  present  period  very  nearly  in  the  same  inexcitable 
state  with  those  described  by  Mr.  Arkwright.  This  experiment  will 
probably  succeed  well  with  those  varieties  of  the  vine  only  which  produce 
blossoms  somewhat  freely,  and  are  of  hardy  habits ;  but  abundant  crops 
of  fruit  of  these  may  be  obtained  at  any  period  of  the  winter  or  spring 
by  proper  previous  management  of  the  plants,  and  by  the  application  of  a 
higher  or  lower  degree  of  temperature. 

The  white  Marseilles  fig,  and  the  other  white  variety  of  Duhamel,  the 
Figue  blanche,  which  very  closely  resemble  each  other  *,  succeed  most  per- 
fectly under  similar  treatment ;  and  if  the  trees  be  taken  from  the  stove  in 
the  end  of  May  or  beginning  of  June,  and  placed  under  a  north  wall  till 
September,  and  be  then  again  transferred  to  the  stove,  they  will  begin  to 
ripen  their  fruit  in  January  or  February,  and  continue  to  produce  it  till 
the  end  of  May  or  the  beginning  of  June,  when  they  should  be  again 
removed  from  the  stove.  The  figs  which  ripen  in  January  and  February 
are  not  so  good  as  those  ripened  in  more  favourable  seasons :  but  they 
are  nevertheless  very  good  fruit,  and  valuable  in  mid-winter ;  and  the 
trees,  if  the  temperature  be  proper  (and  they  are  extremely  patient  of 
heat),  grow  equally  well  in  all  seasons,  if  the  roof  of  the  stove  be  properly 
constructed,  and  the  glass  be  of  good  quality. 

So  small  a  quantity  of  the  fruit  which  is  formed  in  the  preceding 
autumn,  of  either  of  those  varieties  of  the  fig,  sets  in  any  climate,  that  it 
will  rarely  be  found  to  deserve  much  attention  ;  and  I  usually  prune  off 
as  much  of  the  annual  wood  as  is  necessary  to  reduce  the  trees  to  such 
forms  and  sizes  as  I  think  most  convenient,  without  paying  any  regard  to 
their  blossom  buds.  It  appears  probable  that  many  of  those  varieties  of 
the  fig  which  will  not  at  all  bear  the  high  temperature  of  a  stove  in 
summer,  may  succeed  well  in  winter  and  early  spring ;  but  I  have  not 
yet  had  sufficient  experience  to  enable  me  to  decide. 

*  Traite  des  Arbres  Fruitiers,  Tom.  I.  page  211. 


290 


LIX.— ON    THE    CULTURE    OF   STRAWBERRIES. 

[Read  before   the  HORTICULTURAL    SOCIETY,  May  17 th,    1825.] 

AT  the  period  when,  in  the  last  year,  I  addressed  to  the  Horticultural 
Society  some  observations  upon  the  culture  of  different  species  and 
varieties  of  strawberries*,  I  had  seen  the  successful  result  of  other 
experiments ;  but  as  my  experience  had  then  been  chiefly  confined  to  a 
single  season,  I  thought  it  better  to  wait  for  the  further  evidence  which 
the  present  spring  has  afforded  me. 

It  is,  I  believe,  the  general  practice  of  gardeners  to  select  the  early 
runners  of  one  season  to  place  in  pots  for  forcing  in  the  following  spring. 
Instead  of  these,  I  selected,  as  soon  as  their  fruit  had  been  gathered,  the 
roots,  which  in  the  mode  of  culture  recommended  in  my  last  commu- 
nication *  upon  the  subject,  had  borne  one  crop  of  fruit ;  but  which  had 
been  planted  too  closely  in  their  beds  to  be  retained  there  long  with 
advantage.  The  roots  of  these,  to  which  a  good  deal  of  mould  remained 
attached,  were  retained  as  perfect  as  was  practicable  ;  but  their  branches, 
which  in  some  varieties  were  become  very  numerous,  and  which  in  all 
were  too  abundant,  were  reduced  to  three  at  most  in  the  large  varieties, 
and  to  four  in  the  smaller ;  and  the  plants  were  all  placed  so  deeply  in 
the  soil,  after  their  old  and  decaying  leaves  had  been  taken  off,  that  their 
buds  alone  remained  above  it.  Soil  of  extremely  rich  quality  had  been 
chosen  for  the  purpose,  and  water  holding  manure  in  solution  was  rather 
abundantly  given  to  the  pots ;  the  plants  I  by  these  means  obtained, 
apparently  owing  to  their  possessing  a  more  copious  reservoir  of  sap 
beneath  the  soil,  afforded  me  a  more  abundant  crop  of  fruit,  and  of 
superior  quality,  to  that  which  I  believe  I  could  have  obtained  from 
younger  plants.  A  single  plant  of  this  kind  will  be  found  sufficient  for  a 
pot,  the  size  of  which  must  be  regulated  by  the  habits  of  the  variety  of 
strawberry. 

Summer  planting  is,  I  think,  always  in  some  degree  objectionable  ; 
because  the  plants  can  never  have  time  enough  to  extend  their  roots  to 
a  sufficient  depth  beneath  the  soil  to  save  themselves  from  being  injured 
by  drought  in  the  following  spring.  But  as  the  whole  extent  of  the  soil 
which  is  allotted  to  produce  strawberries  becomes,  under  this  mode  of 
management,  every  year  productive  of  fruit,  it  may  in  some  situations  be 
the  most  eligible.  Whenever  this  mode  of  culture  is  adopted,  I  would 

*  See  page  283. 


ON    THE    CULTURE    OP    STRAWBERRIES.  291 

recommend  the  kind  of  plants  above  mentioned  to  be  selected,  and  to  be 
treated  in  every  respect  as  if  they  were  to  be  placed  in  pots  for  forcing  ; 
except  that  their  roots  should  be  made  to  extend  as  deeply  as  practicable 
into  the  soil  in  which  they  are  planted.  In  summer  planting  I  have  also 
found  great  advantage  in  using  the  runners  of  the  preceding  year  :  these 
had  been  planted  with  a  dibble  within  three  inches  of  each  other,  in  rows, 
and  with  intervals  of  only  six  inches  between  the  rows,  till  the  ground  in 
summer  was  ready  to  receive  them  ;  a  very  small  space  was  thus  found 
to  afford  plants  enough  for  a  large  plantation  ;  and  these  having  acquired 
greater  strength,  with  more  strong  and  more  numerous  roots,  afforded  a 
much  more  copious  produce  in  the  following  season  than  could  possibly 
have  been  obtained  from  younger  plants.  By  placing  the  plants  ulti- 
mately near  each  other — those  of  the  large  varieties  within  six  inches  of 
each  other  in  the  rows,  and  with  intervals  of  fourteen  inches  between  the 
rows  ;  and  those  of  the  smaller  varieties  within  four  inches  of  each  other 
in  the  rows,  and  with  intervals  of  a  foot  only  between  the  rows — as  large, 
or  nearly  as  large,  a  weight  of  fruit  may  be  obtained,  I  think,  from  any 
given  extent  of  ground,  as  by  planting  early  in  the  spring,  provided  water 
be  supplied  in  the  spring  in  sufficient  quantity ;  but  the  fruit  will  rarely 
rival  that  which  will  be  produced  by  plantations  made  early  in  the 
preceding  spring  either  in  quality  or  size ;  it  will,  nevertheless,  excel 
both  in  quantity  and  quality  the  produce  of  the  preceding  year's  runners 
either  in  the  open  air  or  forcing-house. 

Whenever  strawberry-plants  are  wanted  for  very  early  forcing,  it  is 
advantageous  that  their  roots  should  have  been  well  established  in  their 
pots  in  the  preceding  autumn,  and  well  preserved  through  the  winter ; 
but  for  late  forcing  I  have  obtained  very  good  subjects  by  the  following 
means  : — Plants  which  had  produced  one  crop  of  fruit  were  taken  up  as 
soon  as  all  their  fruit  had  acquired  maturity,  and  were  planted  at  nine 
inches  apart  in  soil  which  had  been  manured  superficially  only,  and  their 
roots  were  spread  horizontally  near  the  surface  of  the  soil ;  late  in  the 
autumn  the  roots  were  as  much  detached  from  the  soil  as  would  have 
been  requisite  if  they  had  then  been  to  be  planted  in  pots,  but  they  were 
replaced  in  the  soil  till  the  end  of  February ;  being  at  that  period  placed  in 
pots,  they  produced  an  abundant  crop  of  very  fine  fruit.  I  found,  under 
this  mode  of  management,  pans  without  any  apertures  to  permit  the 
escape  of  the  water  to  be  preferable  to  pots,  apparently  owing  to  the 
finely-reduced  mould  having  more  perfectly  closed  round  the  fibrous  roots 
in  the  form  of  mud  in  the  pans  than  in  pots  of  the  ordinary  construction. 
In  giving  water  to  plants  which  grow  in  vessels  from  which  it  cannot 

u  2 


202  ON    THE    CULTURE    OF    STRAWBERRIES. 

escape,  the  gardener  will  avoid  supplying  it  in  excess  ;  but  strawberry- 
plants  whilst  growing  are  not  easily  injured  by  any  degree  of  moisture  in 
the  soil.  It  is  scarcely  necessary  to  mention  that  it  will  be  advantageous 
in  the  first,  as  well  as  in  the  second  transplantation,  not  to  detach  the 
roots  more  than  necessary  from  the  soil  in  which  they  have  grown. 


LX.— ON   THE    CULTIVATION     OF   THE     AMARYLLIS    SARNIENSIS,   OR 

GUERNSEY    LILY. 

{Read  before  the  HORTICULTURAL  SOCIETY,  December  2Qth,  1825.] 

So  many  splendid  species  and  varieties  of  Crinum,  and  other  plants  of 
the  Liliaceous  tribe,  have  within  a  few  years  been  introduced  into  our 
gardens,  that  the  culture  of  the  Amaryllis  Sarniensis,  or  Guernsey  Lily, 
notwithstanding  the  unrivalled  splendour  of  its  blossoms  when  closely 
inspected,  has  to  some  extent  ceased  to  interest  the  modern  gardener.  I 
should  consequently  think  the  matter  of  my  present  communication 
scarcely  worth  sending  to  the  Horticultural  Society,  if  I  were  not  per- 
fectly confident  that  the  same  mode  of  culture  is  applicable  to  bulbous 
roots  of  every  kind  which  do  not  flower  freely  (exclusive  of  those  which 
grow  in  water),  and  with  but  little  variation  to  plants  of  every  kind. 
Wishing,  however,  at  the  present  time,  to  confine  myself  to  very  narrow 
limits,  I  shall  simply  relate  the  experiments  which  I  have  made  upon  the 
Guernsey  Lily,  with  the  conclusions  which  I  have  drawn  from  the  result 
of  those  experiments  ;  and  my  narrative  will,  I  think,  be  most  plain  and 
intelligible,  if  I  confine  it  to  treatment,  through  successive  seasons,  of  a 
single  root  of  that  plant. 

The  gardener  possesses  many  means  of  making  trees  produce  blossoms ; 
by  ringing,  by  ligatures,  and  by  depressing  their  branches;  and  the 
increasing  thickness  of  the  bark  of  these  necessarily  obstructs  the  course 
of  the  descending  fluid,  and  thus  tends  to  render  them  productive  of 
blossoms.  But  none  of  these  mechanical  means  can  be  made  to  operate 
upon  the  habits  of  bulbous-rooted  plants ;  and  I  thence  inferred,  that  in 
the  culture  of  these  I  should  best  succeed  by  adopting  such  measures  as 
would  first  occasion  the  generation  of  much  true  sap,  and  subsequently 
promote  in  it  such  chemical  changes  as  would  cause  it  to  generate 
blossoms  ;  and  under  these  impressions  I  made,  amongst  others,  the  fol- 
lowing experiments,  the  results  of  which  have  in  every  respect  answered 
my  expectations  and  wishes. 

A  bulb  of  the  Guernsey  Lily,  which  had  flowered  in  the  autumn  of 


ON    THE    CULTIVATION    OF    THE    AMARYLLIS    SARNIENSIS.  293 

1822,  was  placed  in  a  stove  as  soon  as  its  blossoms  had  withered,  in  a 
high  temperature,  and  damp  atmosphere.  It  was  planted  in  very  rich 
compost,  and  was  amply  supplied  with  water,  which  held  manure  in  solu- 
tion. Thus  circumstanced,  the  bulb,  which  was  placed  in  the  front  of  a 
curvilinear-roofed  stove,  emitted  much  luxuriant  foliage,  which  continued 
in  a  perfectly  healthy  state  till  spring.  Water  was  then  given  in  smaller 
and  gradually  reduced  quantities  till  the  month  of  May,  when  the  pot  in 
which  it  grew  was  removed  into  the  open  air.  In  the  beginning  of 
August  the  plant  flowered  strongly,  and  produced  several  onsets.  These, 
with  the  exception  of  one  ,were  removed ;  and  the  plant,  being  treated  pre- 
cisely as  in  the  preceding  season,  flowered  again  in  August  1824.  In  the 
autumn  of  that  year  it  was  again  transferred  to  the  stove,  and  subjected 
to  the  same  treatment;  and  in  the  latter  end  of  the  last  summer,  both 
bulbs  flowered  in  the  same  pot  with  more  than  ordinary  strength,  the  one 
flower-stem  supporting  eighteen,  and  the  other  nineteen  large  blossoms. 
One  of  these  flowered  in  the  beginning  of  August,  when  its  blossoms  were 
exposed  to  the  sun  and  air  during  the  day,  and  protected  by  a  covering 
of  glass  during  the  night,  by  which  mode  of  treatment  I  hoped  to  obtain 
seeds;  but  the  experiment  was  not  successful.  The  blossoms  of  the 
other  bulb  appeared  in  the  latter  end  of  August,  and  were  placed  in  the 
same  situation  in  the  stove  which  the  bulb  had  occupied  in  the  preceding 
winter ;  and  I  by  these  means  obtained  three  apparently  perfect  seeds. 
One  of  these,  the  smallest,  and  seemingly  the  least  perfect,  was  placed 
immediately  in  a  pot  in  the  stove,  where  it  has  already  produced  a  plant. 
The  old  bulbs  have  been  again  placed  in  the  stove,  where  they  have 
emitted  abundant  foliage,  and  where  I  do  not  doubt  they  will  again 
generate  blossoms. 

In  the  foregoing  experiments,  I  conceive  myself  to  have  succeeded 
in  occasioning  the  same  bulbs  to  afford  blossoms  in  three  successive  sea- 
sons ;  by  having  first  caused  the  production  of  a  large  quantity  of  true 
sap,  and  subsequently,  by  the  gradual  abstraction  of  moisture,  having 
caused  that  sap  to  become  inspissated,  and  in  consequence  adapted  to 
the  production  of  blossom-buds.  Some  gardeners  entertain  an  opinion 
that  bulbs  may  be  excited  to  produce  blossom-buds  by  being  kept  very 
dry,  after  their  leaves  have  withered :  but  I  believe  this  opinion  to  be 
wholly  unfounded,  and  that  the  blossoms  are  always  generated  whilst 
the  living  foliage  remains  attached  to  the  bulb. 

I  have  made  nearly  similar  experiments  upon  some  fibrous-rooted 
plants,  without  the  aid  of  artificial  heat,  with  similar,  and,  to  me,  with 
more  interesting  results,  an  account  of  which  I  shall  reserve  for  a  future 
communication. 


294 


LXL— UPON   THE    CULTURE    OF   CELERY. 

[Read  before  the  HORTICULTURAL  SOCIETY,  December  5th,  1826.] 

THAT  which  can  be  very  easily  done,  without  the  exertion  of  much 
skill  or  ingenuity,  is  very  rarely  found  to  be  well  done,  the  excitement 
to  excellence  being  in  such  cases  necessarily  very  feeble.  The  practice  of 
a  very  large  number  of  British  gardeners,  in  the  management  and  culture 
of  exotic  plants  and  fruits,  and  in  every  difficult  department  of  their 
professions,  probably  approximates  to,  if  it  have  not  in  many  instances 
attained,  perfection  ;  whilst  the  culture  of  many  of  the  common  esculent 
plants  is  still  capable  of  much  improvement.  I  shall  at  present  confine 
my  observations  to  one  of  these,  the  Apium  graveolens,  or  celery.  This 
plant,  under  the  name  of  smallage,  a  worthless  and  almost  poisonous 
weed,  is  found  in  its  wild  state  growing  most  luxuriantly  in  rank  soils  by 
the  sides  of  wet  ditches,  where  it  can  obtain  at  the  same  time  abundant 
food  and  moisture.  Without  being  very  well  supplied  with  food,  it  will 
not  thrive  at  all  in  our  gardens,  and  therefore  it  rarely  fails  to  obtain  a 
proper  quantity  of  manure  ;  but  as  with  this  it  is  in  most  seasons  found 
to  grow  moderately  well,  the  gardener  has  not  paid  due  attention  to  the 
circumstance  of  its  being  naturally  almost  an  aquatic  plant.  I  have 
during  several  seasons  supplied  my  celery  plants  much  more  copiously 
with  water  than  is  usually  done,  and  always  with  the  best  effects ;  but  in 
the  last  excessively  dry  season,  I  gave  water  so  profusely  that  the  ground 
was  constantly  kept  wet ;  and  before  the  plants  were  moulded  up  above 
the  common  level  of  the  ground,  that  to  some  extent  round  their  roots 
was  so  perfectly  saturated  with  moisture  as  to  wholly  preclude  the  proba- 
bility of  the  plants  suffering  by  want  of  it  during  the  remaining  part 
of  the  summer.  My  gardener  had  not  raised  his  plants  at  the  usual 
and  proper  season  in  the  last  spring,  the  seeds  not  having  been  sown  till 
nearly  the  end  of  April ;  but  nevertheless  the  plants  had  acquired  in  the 
middle  of  September  nearly  the  height  of  five  feet.  Not  the  quantity 
only,  but  the  quality  also  of  the  produce,  was  greatly  improved  by  the 
abundant  supply  of  water ;  for  it  became,  as  might  have  been  inferred, 
more  crisp  and  tender.  The  rows  were  five  feet  distant  from  each  other ; 
but  those  spaces  were  not  sufficiently  wide  to  permit  the  plants  to  be 
moulded  up  to  the  proper  height ;  and  this  circumstance,  joined  to  the 
preternatural  tenderness  of  the  leaf-stalks,  caused  those  to  be  broken 
and  beaten  down  so  much  by  the  first  windy  weather,  that  my  crop, 
though  very  excellent,  was  not  nearly  as  perfect  as  it  might  have  been. 


UPON    THE    CULTURE    OF    CELERY.  295 

The  plants  also  were  placed  within  about  eight  inches  of  each  other  in 
the  rows ;  and  their  foliage  was  so  injuriously  crowded,  that  I  believe  I 
might  have  obtained  as  large,  if  not  a  larger  quantity  of  marketable 
produce,  if  only  half  as  many  plants  had  been  used. 

I  have  little  more  to  add  to  the  excellent  directions  *  which  Mr.  Judd 
has  given  in  our  Transactions  for  the  culture  of  this  plant,  except  that 
I  believe  wide  intervals  between  the  rows,  and  between  the  plants  in  the 
rows,  when  food  and  water  are  abundantly  given,  will  be  found  beneficial. 
I  also  think  that  in  preparing  the  bed  into  which  the  plants  are  first 
removed  from  the  seed-bed,  considerable  advantages  will  be  obtained  by 
covering  a  thin  layer  of  dung,  not  in  a  very  rotten  state,  with  about  two 
inches  deep  of  mould ;  for  under  these  circumstances,  whenever  the 
plants  are  removed,  the  dung  will  adhere  tenaciously  to  their  roots ; 
and  it  will  not  be  necessary  to  deprive  the  plants  of  any  part  of  their 
leaves.  Younger  and  smaller  plants  may  therefore  be  used  ;  for  their 
growth,  under  the  preceding  circumstances,  will  not  be  at  all  checked ; 
and  I  need  not  point  out  to  the  experienced  gardener,  that  the  younger 
his  plants  are,  the  less  subject  they  will  be  to  run  to  seed,  or  pipe, 
as  it  is  called,  in  the  autumn. 


LXII.— UPON   THE    CULTURE    OF   THE    PRUNUS    PSEUDO-CERASUS,    OR 

CHINESE   CHERRY. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  2Qth,  1827.] 

THE  Prunus  Pseudo-Cerasus,  or  Chinese  cherry,  has  been  so  recently  ~f 
introduced  into  Europe,  and  has  been  hitherto  so  little  propagated 
or  cultivated,  that  probably  not  even  its  name  is  known  to  the  greater 

*  See  Horticultural  Transactions,  Volume  III.  page  45. 

f  This  cherry  was  introduced  from  China  by  Mr.  Samuel  Brookes,  of  Ball's  Pond,  in  1819, 
and  he  presented  a  plant  of  it  in  1 822  to  the  Horticultural  Society.  It  has  since,  in  two 
instances,  been  imported  from  China  by  the  Society,  through  the  assistance  of  Mr.  Reeves.  In 
the  year  1824,  it  produced  a  crop  of  fruit  in  one  of  the  houses  in  the  Chiswick  garden,  which 
ripened  within  fifty  days  from  the  time  the  blossoms  opened.  In  that  year,  a  figure  of  the  plant 
in  flower  was  published  by  Mr.  Bellenden  Ker,  in  the  Botanical  Register,  tab.  800,  with  the 
name  of  Prunus  paniculata,  under  the  impression  that  it  was  the  species  so  named  by  Thunberg. 
It  received  its  present  name  of  Prunus  Pseudo-Cerasus  from  Mr.  Lindley,  in  his  report  on  the 
New  and  Rare  Plants  (see  Horticultural  Transactions,  Vol.  IV.  page  90)  which  had  flowered 
in  the  garden  at  Chiswick,  previously  to  March  1824.  It  is  readily  distinguished  as  a  distinct 
species  from  the  common  cherry  and  the  morello  cherry,  by  its  bearing  its  flowers  in  racemes, 
and  by  the  peduncles  being  hairy.  It  is  known  in  China  by  the  name  of  Yung  Fo,  but  is  only 
cultivated  as  an  ornamental  plant  at  Canton,  where  it  rarely  produces  fruit. 


296  ON    THE    CULTURE    OF    THE    PRUNUS    PSEUDO-CERASUS. 

number  of  gardeners.  It  lias,  however,  properties  and  qualities  which 
will  render  it  an  acquisition  of  considerable  value ;  and  I  am  perfectly 
confident  that  it  has  not  yet  been  seen,  in  this  country,  nearly  in  the 
greatest  state  of  excellence  which  it  is  capable  of  acquiring.  I  have 
therefore  addressed  to  the  Horticultural  Society  the  following  obser- 
vations upon  the  propagation  and  culture  of  it,  believing  that  I  am 
better  acquainted  with  the  means  of  propagating  it  than  any  other 
person  is,  though  I  am  sensible  that  I  am  but  ill  prepared  to  execute 
the  task  which  I  have  undertaken. 

I  received  a  plant  of  the  Chinese  cherry  from  the  garden  of  the 
Horticultural  Society  in  the  summer  of  1824,  after  it  had  produced  its 
crop  of  fruit ;  and  it  was  preserved  under  glass,  and  subjected  to  a  slight 
degree  of  artificial  heat,  till  the  autumn  of  that  year.  It  appeared 
very  little  disposed  to  grow,  but  produced  one  young  shoot,  which 
afforded  me  a  couple  of  buds  for  insertion  in  stocks  of  the  common 
cherry.  Soon  after  Christmas  the  tree  was  placed  in  a  pine-stove, 
where  it  presently  blossomed  abundantly,  and  its  fruit  set  perfectly 
well,  as  it  had  previously  done  in  the  garden  of  the  Society,  and  it 
ripened  in  March.  The  cherries  were  middle-sized,  or  rather  small 
compared  with  the  larger  varieties  of  the  common  cherry ;  they  were 
of  a  reddish  amber  colour,  very  sweet  and  juicy,  and  excellent  for  the 
season  in  which  they  ripened.  The  roots  of  the  tree  were  confined  to 
rather  a  small  pot,  and  the  plant  was  not  even  in  a  moderately  vigorous 
state  of  growth ;  I  therefore  infer  that  the  fruit  did  not  acquire  either 
the  size  or  state  of  perfection  which  it  would  have  attained  if  the 
tree  had  been  larger,  and  in  a  vigorous  state  of  growth,  and  the  season 
of  the  year  favourable. 

I  inserted  the  two  buds  which  I  had  obtained  into  stocks  of  the 
common  cherry ;  and  they  seemed  to  take  well,  but  both  appeared  lifeless 
in  the  spring,  though  one  vegetated  late  in  the  summer,  and  is  now 
bearing  a  few  cherries  in  the  pine-stove. 

During  the  last  spring  and  early  part  of  the  summer,  the  old  tree 
retained  in  the  stove  put  out  very  numerous  roots  from  the  bases  of 
its  young  branches,  similar  to  those  emitted,  under  similar  circum- 
stances, by  the  vine ;  and  I  thence  inferred  that  the  species  might  be 
readily  propagated  by  cuttings ;  and  having  planted  some  cuttings  in 
the  pine-stove  this  year,  in  January,  I  have  proved  that  plants  may 
be  thus  raised  with  perfect  facility. 

I  endeavoured  to  obtain  seedling  plants  in  the  present  spring ;  but 
a  single  seed  only  has  vegetated.  The  remainder  decayed  without 


ON    THE    CULTURE    OF    THE    PRUNUS    PSEUDO-CERASUS.  297 

vegetating,  but  owing  to  what  cause  I  am  at  present  ignorant.  I  do 
not  however  doubt  of  better  future  success,  or  that  numerous  varieties 
of  this  species  of  cherry  will  be  readily  obtained  from  seedling  plants. 

I  intended  to  have  obtained  a  very  early  crop  of  cherries  from  the  old 
tree  in  the  present  year,  and  for  that  purpose  I  had  placed  it  in  the 
open  air,  to  winter,  in  the  autumn  ;  proposing  to  introduce  it  into  the 
stove  in  November.  But  unfortunately  going  from  home  for  a  few  days 
just  before  the  time  when  I  proposed  to  introduce  it  into  the  pine-stove, 
two  very  severe  frosty  nights  occurred,  which  so  much  injured  the 
blossom-buds,  which  were  very  far  advanced,  that  they  all  fell  off 
abortively,  as  those  of  a  peach-tree  would  certainly  have  done  under 
similar  circumstances.  The  tree,  however,  did  not  sustain  further  injury, 
and  I  believe  that  the  species  will  be  found  quite  hardy  enough  to  succeed 
in  the  open  air,  if  trained  to  a  wall.  It  is  much  disposed  to  vegetate 
very  early  in  the  spring;  and  thence  its  blossoms,  like  those  of  the  apricot- 
tree,  will  probably  require  some  protection.  This  highly -excitable  habit 
seems  to  indicate  a  plant  of  a  cold  climate,  probably  that  of  Tartary  ; 
and  I  am  inclined  to  think  that  it  will  ripen  its  fruit  very  early  in  the 
open  air  in  this  country. 

In  the  last  summer,  and  in  the  present  year,  I  have  supplied  the  old 
plant  rather  freely  with  manure  in  a  liquid  state  ;  and  it  is  now  growing 
with  very  great  vigour,  and  will  afford  me  a  large  number  of  buds  and 
cuttings.  Being  wholly  ignorant  of  the  habits  of  the  species,  and  fearful 
of  destroying  the  only  tree  I  possessed,  I  proceeded  with  much  more 
caution  than  usual  in  the  use  of  liquid  manure  ;  for  I  generally  use  it 
very  freely,  and  without  apprehension  of  ill  effects,  experience  having 
satisfied  me  that  plants  of  all  kinds,  even  heaths*,  very  often  perish 
through  want  of  food,  and  that  they  very  rarely  suffer  from  excess  of  it, 
when  their  roots  are  confined  to  the  narrow  limits  of  a  pot. 

*  A  plant  of  heath  (Erica  australis,  I  believe)  was  placed  under  my  care  in  the  spring  of  1823, 
with  a  request  that  I  would  treat  it  in  any  way  I  wished.  It  was  then  about  eight  inches  high, 
and  growing  in  a  small  quantity  of  peat  earth  and  sand  ;  and  in  that  it  continued  to  grow  with 
very  little  increase  of  size  till  the  following  spring.  From  that  period  it  was  regularly  supplied 
\\ith  water,  which,  though  clear,  was  considerably  tinged  with  an  infusion  of  pigeon's  dung. 
I  was  apprehensive  this  kind  of  food  would  prove  fatal  to  it ;  but  far  from  this  being  the  result, 
the  plant  grew  with  excessive  health  and  vigour,  emitting  very  numerous  branches,  eight  of 
which  exceeded  eighteen  inches  each  in  length.  It  was  then  taken  away  by  the  owner  of  it, 
and  I  have  not  since  seen  or  heard  of  it,  but  it  left  me  in  a  state  of  luxuriant  health.  How  far 
other  species  of  this  genus  will  bear  being  thus  abundantly  fed  with  liquid  manure,  is  an 
interesting  question  to  the  gardener. 


298 


LXIIL— AN  ACCOUNT  OF  SOME    IMPROVEMENTS    IN  THE    CONSTRUCTION 

OF   HOTBEDS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  July  3rd,  1827.] 

I  SUBMIT  an  account  of  a  small  addition  which  I  have  made  in  the 
machinery  of  a  common  hotbed,  from  the  use  of  which  I  believe  that 
every  gardener  who  has  occasion  to  raise  cucumbers  and  other  plants  in 
winter,  or  very  early  in  the  spring,  will  be  able  to  derive  very  considerable 
advantages.  At  these  periods  of  the  year,  it  is  not  easy  to  give  the  plants 
a  sufficiently  high  temperature,  with  proper  change  of  air,  however  well 
the  bed  may  have  been  constructed,  and  with  whatever  care  the  material 
which  composes  it  may  have  been  prepared  ;  and  the  sudden  changes  of 
temperature  which  often  occur  in  the  climate  of  England  will  frequently 
subject  the  roots  of  the  plants  to  be  injured  by  excess  of  heat,  and  the 
mould,  when  lying  upon  horse -dung,  to  be  what  is  called  by  the  gardener 
barned,  that  is,  I  believe,  so  much  impregnated  with  ammonia,  that  the 
roots  of  the  plants  cannot  retain  life  in  it.  Another  defect  of  the  common 
hotbed  is,  that  whilst  its  interior  part  is  excessively  hot,  so  little  heat 
ascends  through  the  mould,  that  a  covering  of  glass  alone  does  not  afford  suf- 
ficient protection  to  any  tender  plant  in  very  cold  weather,  during  the  night. 

By  means  of  the  machinery  which  I  shall  proceed  to  describe  and  to 
recommend,  abundant  air  may  be  given  at  all  times,  and  so  high  a 
temperature  preserved,  that,  with  a  hotbed  of  a  very  moderate  degree 
of  strength,  the  most  tender  plant  will  be  perfectly  protected  without  any 
other  covering  than  that  of  an  ordinary  glass-light  during  the  severest 
frost  of  our  climate,  provided  the  spaces  where  the  panes  of  glass  overlap 
each  other  be  perfectly  closed. 


The  annexed  design  will  give  a  sufficiently  accurate  representation  of 


IMPROVEMENT    IN    THE    CONSTRUCTION    OF    HOTBEDS.  299 

the  apparatus  which  I  have  above  recommended.  A,  B,  C,  D,  is  a  hot- 
bed, resting  upon  an  inclined  plane  of  earth.  E,  the  frame;  F,  G,  a  pipe, 
made  of  a  slender  oak  pole ;  and  H,  I,  K,  smaller  pipes  fixed  into  the 
larger  one,  through  which  the  air  which  enters  the  latter  at  F  ascends 
into  the  hotbed.  The  tube  of  the  large  pipe  is  one  inch  and  a  half,  and 
that  of  the  smaller  three-quarters  of  an  inch  diameter.  The  smaller  tubes 
have  near  their  upper  ends  two  horizontal  apertures,  through  which  the 
heated  air  passes  laterally  into  the  frame.  I  consider  three  of  the  large 
pipes  to  be  fully  sufficient  to  give  heated  air  to  a  bed  twenty  feet  long  ; 
the  heated  air  entering  at  all  times  very  rapidly,  and  consequently  always 
keeping  all  within  the  frame  in  motion.  The  larger  pipes  might,  I  con- 
ceive, be  with  advantage  made  of  cast-iron. 

If  the  heat  of  the  air  be  at  any  time  excessive,  it  may  be  lessened  by 
opening  the  end  of  the  tube  at  G,  where  it  is  usually  kept  closed.  The 
hotbed  in  which  I  have  placed  the  above-described  kind  of  tubes  is 
composed  almost  wholly  of  leaves ;  but  the  mass  of  these  is  great,  and  the 
temperature  in  consequence  high.  I  immersed  a  deep  pot  into  the  leaves, 
and  caused  the  heated  air  of  the  tube  K  to  ascend  into  it,  having  pre- 
viously shortened  the  tube,  and  fitted  it  accurately  to  the  aperture  of  the 
pot,  placing  a  thermometer,  with  some  eggs  of  the  common  domestic 
fowl  within  it,  with  the  view  of  ascertaining  whether  these  could  be 
hatched  by  such  means.  I  have  not  yet  seen  the  result ;  but  the  temper- 
ature of  the  ascending  current  of  air  which  arises  into  the  pot,  and  of 
course  into  the  frame,  appears  never  to  have  varied  during  fifteen  days 
more  than  three  degrees,  the  lowest  temperature  being  101°,  and  the 
highest  104° ;  and  it  has,  of  course,  been  nicely  adapted  to  both  the  pur- 
poses for  which  it  was  intended. 

I  have  formerly  ascertained,  that  the  power  of  a  current  of  heated  air 
when  made  to  enter  a  pit,  or  chamber  of  any  kind,  \vas  found  greatly  to 
exceed  the  calculation  which  I  had  previously  made;  and  in  the  last 
winter,  very  contrary  to  my  expectations,  a  very  feeble  current  of  air,  the 
temperature  of  which  was  below  50°,  proved  sufficient  to  preserve  gera- 
niums which  were  placed  close  to  the  glass  in  the  severest  frost  from 
receiving  the  slightest  injury. 

The  operation  of  a  hotbed  into  which  a  pipe  is  introduced  in  the 
manner  above  mentioned  has  been  observed  by  me  only  during  the  spring 
and  part  of  the  summer  of  the  present  year ;  but  the  results  have  been  so 
satisfactory,  that  I  can,  with  the  utmost  confidence,  recommend  the 
machinery  which  I  have  described,  particularly  when  tender  plants  of  any 
species  are  to  be  raised  in  cold  seasons  of  the  year. 


300 


LXIV.— ON  THE  CULTURE  OF  THE  POTATO. 

[Read  before  the    HORTICULTURAL    SOCIETY,   July   ~\st,   1828.] 

WHATEVER  may  have  been  the  amount  of  the  advantages  or  injury 
which  the  British  Empire  has  sustained  by  the  very  widely-extended 
culture  of  the  potato,  it  is  obvious  that  under  present  existing  circum- 
stances it  must  continue  to  be  very  extensively  cultivated  ;  for  though  it 
is  a  calamity  to  have  a  numerous  population  who  are  compelled  by  poverty 
to  live  chiefly  upon  potatoes,  it  would  certainly  be  a  much  greater  calamity 
to  have  the  same  population  without  their  having  potatoes  to  eat. 

Under  this  view  of  the  subject,  I  have  been  led  to  endeavour  to  ascer- 
tain, by  a  course  of  experiments,  the  mode  of  culture  by  which  the  largest 
and  most  regular  produce  of  potatoes,  and  of  the  best  quality,  may  be 
obtained  from  the  least  extent  and  value  of  ground  ;  and  having  succeeded 
best  by  deviating  rather  widely  from  the  ordinary  rules  of  culture,  I  send 
the  following  account  of  the  results  of  my  experiments.  These  were 
made  upon  different  varieties  of  potatoes ;  but  as  the  results  were  in  all 
cases  nearly  the  same,  I  think  that  I  shall  most  readily  cause  the  practice 
I  recommend  to  be  understood  by  describing  minutely  the  treatment  of  a 
single  variety  only,  which  I  received  from  the  Horticultural  Society,  under 
the  name  of  Lankman's  potato. 

The  soil  in  which  I  proposed  to  plant  being  very  shallow,  and  lying 
upon  a  rock,  I  collected  it  with  a  plough  into  high  ridges  of  four  feet 
wide,  to  give  it  an  artificial  depth.  A  deep  furrow  was  then  made  along 
the  centre  and  highest  part  of  each  ridge  ;  and  in  the  bottom  of  this, 
whole  potatoes,  the  lightest  of  which  did  not  weigh  less  than  four  ounces, 
were  deposited,  at  only  six  inches'  distance  from  the  centre  of  one  to  the 
centre  of  another.  Manure,  in  the  ordinary  quantity,  was  then  introduced, 
and  mould  was  added,  sufficient  to  cover  the  potatoes  rather  more  deeply 
than  is  generally  done. 

The  stems  of  potatoes,  as  of  other  plants,-  rise  perpendicularly  under 
the  influence  of  their  unerring  guide,  gravitation,  so  long  as  they  continue 
to  be  concealed  beneath  the  soil ;  but  as  soon  as  they  rise  above  it,  they 
are,  to  a  considerable  extent,  under  the  control  of  another  agent,  light. 
Each  inclines  in  whatever  direction  it  receives  the  greatest  quantity  of 
that  fluid,  and  consequently  each  avoids,  and  appears  to  shun,  the  slmde 
of  every  contiguous  plant.  The  old  tubers  being  large  and  under  the 
mode  of  culture  recommended  rather  deeply  buried  in  the  ground,  the 
young  plants  in  the  early  part  of  the  summer  never  suffer  from  want  of 
moisture ;  and  being  abundantly  nourished,  they  soon  extend  themselves 


ON  THE  CULTURE  OF  THE  POTATO.  301 

in  every  direction  till  they  meet  those  of  the  contiguous  rows,  which  they 
do  not  overshadow,  on  account  of  the  width  of  the  intervals. 

The  stems  being  abundantly  fed,  owing  to  the  size  of  the  old  tubers, 
rise  from  the  ground  with  great  strength  and  luxuriance,  support  well 
their  foliage,  and  a  larger  breadth  of  this  is  thus,  I  think,  exposed  to  the 
light  during  the  whole  season  than  under  any  other  mode  of  culture 
which  I  have  seen ;  and  as  the  plants  acquire  a  very  large  size  early  in 
the  summer,  the  tubers,  of  even  very  late  varieties,  arrive  at  a  state  of 
perfect  maturity  early  in  the  autumn. 

Having  found  my  crops  of  potatoes  to  be  in  the  last  three  years, 
during  which  alone  I  have  accurately  adopted  the  mode  of  culture  above 
described,  much  greater  than  they  had  ever  previously  been,  as  well  as 
of  excellent  quality,  I  was  led  to  ascertain  the  amount  in  weight  which 
an  acre  of  ground  such  as  I  have  described,  the  soil  of  which  was 
naturally  poor  and  shallow,  would  produce.  A  colony  of  rabbits  had, 
however,  in  the  last  year  done  a  good  deal  of  damage,  and  pheasants 
had  eaten  many  of  the  tubers  which  the  rabbits  had  exposed  to  view ; 
but  the  remaining  produce  per  acre  exceeded  five  hundred  and  thirty-nine 
bushels  of  eighty-two  pounds  each, — two  pounds  being  allowed  in  every 
bushel  on  account  of  a  very  small  quantity  of  earth  which  adhered  to 
them. 

The  preceding  experiments  were  made  with  a  large  and  productive 
variety  of  potato  only ;  but  I  am  much  inclined  to  think  that  I  have 
raised,  and  shall  raise  in  the  present  year,  1828,  nearly  as  large  a 
produce  per  acre  of  a  very  well-known  small  early  variety,  the  ash-leaved 
kidney  potato.  Of  this  variety  I  selected  in  the  present  spring  the 
largest  tubers  which  I  could  cause  to  be  produced  in  the  last  year  ;  and 
I  have  planted  them  nearly  in  contact  with  each  other  in  the  rows,  and 
with  intervals,  on  account  of  the  shortness  of  their  stems,  of  only  two  feet 
between  the  rows.  The  plants  at  present  display  an  unusual  degree  of 
strength  and  vigour  of  growth,  arising  from  the  very  large  size  (for  that 
variety)  of  the  planted  tubers ;  and  as  large  a  breadth  of  foliage  is  exposed 
to  the  light  by  the  small,  as  could  be  exposed  by  a  large  variety  ;  and  as  I 
have  always  found  the  amount  of  the  produce,  under  any  given  external 
circumstance,  to  be  regulated  by  the  extent  of  foliage  which  was  exposed 
to  light,  I  think  it  probable  that  I  shall  obtain  as  large,  or  very  nearly 
as  large,  a  crop  from  the  small  variety  in  the  present  year  as  I  obtained 
from  the  large  variety  in  the  last.  I  have  uniformly  found  that,  to 
obtain  crops  of  potatoes  of  great  weight  and  excellence,  the  period  of 
planting  should  never  be  later  than  the  beginning  of  March. 


302  ON    THE    CULTURE    OF    THE    POTATO. 

POSTSCRIPT. 

March  23,  1829. — Somewhat  contrary  to  my  expectations,  the  produce 
of  the  small  early  potato  exceeded  very  considerably  that  of  the  large 
one  above  mentioned  ;  being  per  acre  665  bushels  of  82  pounds.  It  is 
usually  calculated  by  farmers  that  eighty  pounds  of  potatoes,  though 
eaten  raw,  after  they  have  begun  to  germinate,  will  afford  two  pounds  of 
pork ;  and  I  doubt  much  if  the  haulm,  and  the  whole  of  the  manure 
made  by  the  hogs,  were  restored  to  the  ground,  whether  it  would  be  in 
any  degree  impoverished.  I  am  not  satisfied  that  it  would  not  be 
enriched, — an  important  subject  for  consideration  in  a  country  of  which 
the  produce  is  at  present  unequal  to  support  its  inhabitants,  and  which 
produce  is,  I  confidently  believe  and  fear,  growing  gradually  less,  whilst 
the  number  of  its  inhabitants  is  rapidly  increasing. 


LXV.— ON     THE     CULTIVATION     OF     THE     PINE-APPLE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  Aug.  IVth,  1828.] 

I  HAVE  now  completed  a  long  course  of  experiments  upon  the  culture 
of  the  pine-apple  in  the  dry  stove,  the  object  of  which  has  been  to  ascer- 
tain the  means  by  which  that  species  of  fruit  might  be  most  advan- 
tageously grown,  and  particularly  at  those  periods  of  the  year  when  the 
scarcity  of  other  fruits  gives  it  an  additional  value.  In  these  experiments 
I  have  endeavoured  to  ascertain  the  effects  of  excess  of  drought  and  of 
moisture,  and  of  very  high  and  of  very  low  temperature.  I  have,  of 
course,  sacrificed  many  plants  in  experiments  which  I  neither  found  nor 
expected  to  find  successful ;  but  from  these  I  have  derived  information 
which  I  believe  will  prove  useful  to  the  cultivators  and  advantageous  to 
the  consumers  of  that  species  of  fruit  *. 

The  effects  of  a  very  dry  atmosphere  necessarily  were  an  inspissated 

*  I  have,  in  a  communication  last  year  to  the  Horticultural  Society,  shown  that  the  mould  in 
pots  circumstanced  as  those  which  contain  my  pine-apple  plants  are,  acquires  a  temperature 
very  nearly  equal  to  that  of  the  aggregate  temperature  of  the  air  in  the  house,  but  not  subject  to 
such  extensive  variations.  Thus,  if  the  highest  temperature  of  the  air  within  the  house  during 
the  day  be  90°  and  the  lowest  during  the  night  be  70°,  the  temperature  of  the  mould  in  the 
pots  will  nearly  approximate  the  arithmetical  mean  80°  :  and  surely  the  intelligent  gardeners 
of  the  present  day  must  be  fully  sensible  that  mould  at  eighty  degrees  is  warm  enough  without 
the  aid  of  the  irregular  and  ungovernable  heat  of  a  bark-bed,  whatever  their  ignorant  prede- 
cessors who  first  introduced  the  bark -bed  into  the  pine-stove  may  have  thought. 


ON    THE    CULTIVATION    OF    THE    PINE-APPLE.  303 

state  of  the  sap  of  the  plant ;  and  this,  as  it  does  in  all  other  similar  cases, 
led  to  the  formation  of  blossom-buds  and  of  fruit ;  and  it  thus  operated 
upon  some  pine-apple  plants  to  such  an  extent  as  to  cause  even  the  scions 
from  their  roots  to  rise  from  the  soil  with  an  embryo  pine -apple  upon  the 
head  of  each,  and  every  plant  to  show  fruit  in  a  very  short  time,  whatever 
were  its  state  and  age. 

Very  low  temperature,  under  the  influence  of  much  light,  by  retarding 
and  diminishing  the  expenditure  of  sap  in  the  growth  of  the  plants, 
comparatively  with  its  creation,  produced  nearly  similar  effects,  and 
caused  an  injuriously  early  appearance  of  fruit. 

Very  high  temperature,  if  accompanied  with  a  sufficiently  humid 
state  of  the  atmosphere,  I  found  beneficial  at  all  seasons  of  the  year 
under  a  curvilinear  iron-roofed  house  ;  for  this  admitted  as  much 
light  even  in  the  middle  of  winter  as  the  pine-apple  plants  appeared  to 
require. 

Many  months  previously  to  the  publication  of  Mr.  Daniel's  very  excel- 
lent communication  in  the  Transactions  of  this  Society  (Vol.  VI.  page  1), 
and  without  being  in  any  degree  acquaintedwith  his  opinions,  I  had  placed 
unglazed  shallow  earthen  pans  upon  the  flues  of  my  curvilinear-roofed 
stove,  such  as  he  has  recommended,  nearly  in  contact  with  each  other ; 
and  I  had  increased  the  dampness  of  the  air  within  the  house  by  keeping 
the  ground,  which  is  not  paved,  constantly  very  wet.  The  effects  of 
excess  of  humidity  in  the  air  of  the  house  were,  as  might  have  been 
anticipated,  diametrically  opposite  to  those  which  had  resulted  from 
drought ;  and  the  plants  grew  so  rapidly  as  to  become  soon  too  large 
for  the  spaces  allotted  to  them,  without  indicating  at  any  season  of 
the  year  a  disposition  to  show  fruit.  By  subjecting  these  plants  to  the 
influences  of  the  drier  atmosphere,  their  exuberance  of  growth  was 
soon  checked;  and  the  production  of  fruit  immediately  followed  in 
every  season  of  the  year,  provided  that  a  sufficiently  high  temperature 
was  given, 

I  have  never  cultivated  the  white  Providence  pine-apple,  because  I 
never  thought  it  worth  culture  ;  nor  any  of  the  large  varieties,  excepting 
a  very  few  of  the  Enville ;  and  I  have  scarcely  ever  had  a  plant  which 
has  not  fruited  within  less  than  twenty  months  of  the  period  at  which  the 
sucker  was  taken  from  the  parent  plant ;  and  the  suckers  were  invariably 
taken  off  at  the  same  time  with  the  fruit.  The  utmost  horizontal  space 
which  I  have  ever  allowed  to  any  plant  has  not  exceeded  twenty-three  by 
twenty-four  inches  during  the  latter  half  of  its  life,  and  less  than  half  that 
space  during  the  preceding  part  of  it ;  and  I  in  consequence  have  never 


304  ON    THE    CULTIVATION    OF    THE    PINE-APPLE. 

had  a  pine-apple  which  has  weighed  quite  four  pounds  *.  But  I  possess 
at  the  present  moment  succession  plants  of  the  greatest  excellence,  and 
such  as  I  could  cause  to  bear  fruit  of  very  great  weight,  if  I  chose  to 
give  them  age  and  space  ;  for  comparatively  with  the  age  and  spaces 
allotted  to  the  plants  in  my  fruiting-house,  the  fruit  of  my  older  plants  is 
of  very  large  size,  and  in  every  respect  exceedingly  perfect.  I  also  obtain 
a  regular  succession  of  produce  without  having  ever  many  pine-apples 
ripe  at  the  same  period  of  the  year ;  and  I  can  venture  confidently  to 
assert  that  I  could  without  difficulty,  in  properly  constructed  stoves, 
cause  crops  of  pine-apples  to  ripen  regularly,  and  without  failure,  at  any 
appointed  period  of  the  year.  Some  varieties  of  the  pine-apple  appear 
to  me  to  be  capable  of  acquiring  a  very  high  state  of  perfection  under  a 
curvilinear  iron  roof  in  the  most  unfavourable  seasons  of  the  year ;  and 
the  most  excellent  fruit  of  the  species,  in  my  estimation,  which  I  have 
ever  seen  has  been  that  of  the  St.  Vincent's  or  green  olive  in  the  middle 
of  winter  :  and  my  guests  have,  in  more  than  one  instance,  unanimously 
coincided  with  me  in  opinion. 

I  have  raised  as  many  succession  plants  as  I  have  wanted  (and  I  have 
used  a  very  large  number  comparatively  with  the  extent  of  my  stoves), 
by  placing  my  suckers  and  young  plants  to  take  root  and  grow  over  the 
flues  between  the  larger  plants ;  but  crowns  and  suckers  never  emit  roots 
more  freely,  nor  afford  better  plants,  than  they  do  when  placed  in  a 
common  hotbed. 

I  often  plant  suckers  without  detaching  them  from  the  roots  and  stems 
of  the  parent  plants;  and  for  the  purpose  of  receiving  such  roots  and  long 
stems,  I  employ  pots  which  vary  in  depth  from  eighteen  to  twenty-two 
inches  with  a  cylindrical  diameter  of  eleven  inches  only.  Much  time  is 
thus  gained  ;  for  plants  thus  raised,  if  properly  managed,  will  afford 
good  fruit  at  a  year  old ;  and  they  are  capable  whilst  young  of  being 
very  closely  packed  together. 

Under  a  curvilinear  iron  roof,  it  will  be  necessary  to  shade  the  pine- 
apple plants  during  the  first  bright  days  of  the  spring,  or  the  healthful 
verdant  colour  of  their  leaves  will  be  tarnished  ;  and  also  to  shade  the 
plants  during  the  long  and  bright  days  of  summer  from  ten  o'clock  in 
the  morning  to  three  in  the  afternoon,  or  the  fruit  will  ripen  with 
injurious  rapidity  at  that  season.  For  this  purpose  I  employ  a  net,  of 
the  kind  I  use  to  cover  cherry-trees,  doubled. 

*  Since  the  above  was  written,  I  sent  a  black  Jamaica  pine-apple  to  the  Horticultural  Society, 
the  produce  of  a  plant  which  was  some  months  less  than  two  years  old,  and  which  was  confined 
to  the  space  above  mentioned,  which  exceeded  4^  Ibs.  in  weight ;  but  I  have  had  no  other 
quite  so  heavy. 


ON    THE    CULTIVATION    OF    THE    PINE-APPLE.  305 

The  gardener  who  has  never  cultivated  pine- apples  in  a  dry  stove, 
should  bear  in  mind  that  in  giving  water  he  should  put  as  much  at  once 
into  each  pot  as  will  moisten  the  mould  to  the  bottom  of  it,  and  avoid 
watering  very  frequently. 

There  are  in  different  parts  of  England  enormous  heaps  of  coal-dust 
lying  at  the  tops  of  the  pits  of  no  value  whatever,  and  in  situations  where 
pine-apples  might  be  conveyed  within  three  days  to  London  by  water 
carriage ;  and  I  am  perfectly  confident  that  these  may  be  raised  by  the 
mode  of  culture  recommended  in  this,  and  former  communications,  at 
less  than  half  the  expense  now  incurred ;  and  I  do  not  entertain  the 
slightest  doubt,  that  as  large,  and  even  larger  pine-apples,  may  be  raised 
without,  than  with  a  hot-bed  of  any  kind.  Nothing  can  be  more  easy 
than  the  act  of  giving  a  more  regular  and  uniform  warmth  to  the  roots 
than  that  which  can  be  given  by  the  ever  varying  heat  of  a  bark  bed  ; 
and  a  sufficiently  humid  state  in  the  atmosphere  of  the  house  may  be 
regularly  produced  by  many  different  means. 

Some  gardeners  however  have,  as  I  have  been  informed,  wholly  failed 
in  attempts  to  cultivate  pine-apples  without  the  aid  of  a  bark  bed ;  and 
one  case  of  this  kind  has  come  within  my  own  observation.  In  this  (and 
probably  in  all  others)  the  failure  obviously  arose  from  want  of  sufficient 
humidity  in  the  atmosphere  of  the  house  ;  for  the  plants  not  only  grow 
best,  but  the  fruit  acquires,  I  think,  its  highest  state  of  perfection,  when 
ripened  in  damp  air,  provided  that  there  be  a  sufficient  change  of  it, 
and  that  too  much  water  be  not  given  to  the  roots  of  the  plants.  A 
very  dry  state  of  the  air  in  the  stove  is  noxious,  I  believe,  to  almost 
every  species  of  plant,  and  particularly  to  the  pine- apple  *. 

Whenever  it  is  wished  that  pine-apples  should  be  produced  of  very 
large  size,  it  will  obviously  be  necessary  to  restrain  the  plants  from 
bearing  fruit  till  they  have  acquired  a  greater  age  than  mine  have  ever 
been  permitted  to  acquire;  and  in  such  case  it  will  be  beneficial  to 
remove  the  plants  annually  into  larger  pots.  This,  when  the  pots,  as 
well  as  the  plants,  are  large,  will  not  very  easily  be  done  without  danger 
of  injury  to  the  roots.  It  has  been  my  custom  to  remove  melon  plants 
of  large  size  ;  and  to  preserve  the  roots  of  these  from  injury  in  trans- 
planting, I  have  had  baskets,  of  loose  texture  and  coarse  workmanship, 
and  consequently  of  very  low  price,  made  to  fit  the  pots  from  which  the 

*  Very  dry  air  appears  to  me  to  be  particularly  injurious,  when  it  is  made  to  come  into  contact 
with  the  roots  through  the  sides  of  a  porous  and  unglazed  earthen  pot :  I  suspect,  owing  to 
causes  pointed  out  by  M.  Dutrochet ;  see  L' agent  immtdiat  du  mouvement  vital;  and 
Nouvelles  Recherches  sur  FEndosmose  et  VF.xosmose. 

X 


306  ON    THE    CULTIVATION    OF    THE    PINE-APPLE. 

melon  plants  were  to  be  removed. ;  if  such  baskets  were  to  be  introduced 
into  the  pots  in  which  the  pine-apple  plants  were  placed  in  the  autumn 
of  one  year,  they  would  remain  sufficiently  sound  till  the  following 
autumn  to  enable  the  gardener  to  remove  plants  of  the  largest  size 
without  any  danger  of  injury  to  their  roots.  It  will  also  be  necessary 
when  fruit  of  the  largest  size  is  required,  to  place  the  plants,  at  all 
periods  of  their  growth,  at  considerable  distances  from  each  other, 
because  the  leaves  of  the  pine-apple  plants  act  less  efficiently  in  the 
generation  of  sap,  in  proportion  as  they  are  made  to  take  a  perpendicular 
direction  ;  and  this  direction  they  are  compelled  to  take  when  they  are 
laterally  much  shaded ;  for  the  leaves  of  this  plant,  like  the  stems  of 
potatoe  plants,  as  I  have  remarked  in  the  last  communication  *  which  I 
had  the  honour  to  address  to  this  Society,  are  subject  to  the  conflicting 
influence  of  gravitation  t  and  of  light,  the  one  labouring  to  give  a 
perpendicular,  the  other  a  horizontal  direction  to  the  leaves;  and 
the  comparative  power  of  one  agent  increasing  as  that  of  the  other 
decreases. 

I  shall  conclude  the  present  communication  with  an  account  of  a  very 
simple  and  efficient  method  of  destroying  the  different  species  of  insects 
that  infest  the  pine-apple  plant,  which  I  have  practised  during  the  last 
two  years  with  perfect  success.  Pine-apple  plants  are  not  at  all  injured 
by  having  water  at  the  temperature  of  150°  of  Fahrenheit's  scale  thrown 
upon  and  into  them  with  a  syringe.  The  mealy  bug  does  not  appear  to 
be  injured  by  a  single  washing,  or  immersion  for  a  short  time  in  water 
of  the  above-mentioned  temperature  ;  but  if  the  application  be  repeated 
three  or  four  times  on  as  many  successive  days,  it  wholly  disappears.  My 
gardener  has,  I  have  reason  to  believe,  used  water  of  a  higher  tempera- 
ture than  150°  without  any  injury  to  the  plants ;  but  as  hot  water,  when 
applied  in  the  way  above-mentioned,  will  operate  accordingly  to  the 
compound  ratio  of  its  quantity  and  temperature,  I  would  recommend  the 
gardener,  when  he  first  uses  it,  to  apply  it  to  a  worthless  plant,  and  not 
to  use  water  of  quite  so  high  a  temperature  as  150°. 

Having  some  red  spiders  upon  the  leaves  of  a  fig-tree  in  the  stove,  I 
endeavoured  to  ascertain  the  effects  of  hot  water  upon  these.  The  first 
application  of  it  appeared  only  to  render  them  more  alert  and  active  ;  a 

*  See  page  300. 

t  The  influence  of  gravitation  upon  the  forms  of  plants  is  still  greater  than  I  have  inferred 
in  my  paper  in  the  Philosophical  Transactions  upon  that  subject.  M.  Dutrochet,  having  used 
very  superior  machinery  to  that  employed  by  me,  discovered,  that  if  a  seed  be  made  to  revolve 
upon  its  own  axis,  and  its  axis  of  rotation  made  to  dip  only  a  degree  and  a  half  below  the  hori- 
zontal line,  the  roots  will  always  take  the  descending,  and  the  germs  the  ascending  line,  of 
that  axis. 


ON    THE    CULTIVATION    OF    THE    PINK-APPLE.  307 

second  appeared  to  have  diminished  their  numbers  very  considerably ; 
and  after  a  third  application  I  could  not  discern  any.  Whether  they 
died,  or  marched  off  only,  I  am  ignorant ;  and  the  period  at  which  1 
remove  my  fig-trees  into  the  open  air  having  arrived,  I  had  no  further 
opportunity  of  trying  the  experiment.  I  applied  the  water  to  the  mature 
and  somewhat  old  leaves  only  of  the  fig-trees*. 


LXVI.— UPON  THE    SUPPOSED  CHANGES    OF  THE    CLIMATE  OF  ENGLAND. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  oth,  1829.] 

THERE  are,  I  believe,  few  persons  who  have  noticed,  and  who  can 
recollect,  the  state  of  the  climate  of  England  half  a  century  ago,  who 
will  not  be  found  to  agree  in  opinion  that  considerable  changes  have 
taken  place  in  it ;  and  that  our  winters  are  now  generally  warmer  than 
they  were  at  that  period.  The  opinions  of  such  persons  would  be 
entitled  to  very  little  attention  if  they  were  adduced  to  prove  that  our 
climate  has  grown  colder,  because  they  themselves  being  far  advanced  in 
life,  and  therefore  less  patient  of  cold,  and  being  also  incapable  of 
bearing  the  same  degree  of  exercise  which  kept  them  warm  in  youth, 
might  be  readily  drawn  to  conclude  that  the  severity  of  our  winters  has 
increased.  But  when  their  evidence  tends  to  prove  that  our  winters 
have  grown  warmer,  it  cannot,  I  think,  reasonably  be  rejected.  My  own 
habits  and  pursuits,  from  a  very  early  period  of  my  life  to  the  present 
time,  have  led  me  to  expose  myself  much  to  the  weather  in  all  seasons  of 
the  year,  and  under  all  circumstances  ;  and  no  doubt  whatever  remains 
in  my  mind  but  that  our  winters  are  generally  a  good  deal  less  severe 
than  formerly,  our  springs  more  cold  and  ungenial,  our  summers,  and 
particularly  the  latter  parts  of  them,  as  warm  at  least  as  they  formerly 
were,  and  our  autumns  considerably  warmer ;  and  I  think  that  I  can 
point  out  some  physical  causes,  and  adduce  some  rather  strong  facts,  in 
support  of  these  opinions. 

The  subject  is  one  of  much  importance  to  the  horticulturist,  as  it 
points  out  to  him  in  what  respects  he  ought  to  deviate  from  the  practice  of 

*  During  the  last  season,  several  specimens  of  the  fruit  of  the  pine-apple,  managed  as  above 
described,  were  sent  to  the  Society  by  Mr.  Knight.  They  were  all,  without  exception,  of  the 
very  best  quality  in  point  of  flavour  ;  they  were  universally  destitute  of  fibre  ;  and  in  every 
respect  as  perfectly  grown  as  any  I  ever  saw  of  the  same  size. — March  30,  1829.— Jos.  Sabine, 
Secretary. 

x'2 


308  ON    THE    SUPPOSED    CHANGES    OF    THE    CLIMATE    OF    ENGLAND. 

his  predecessors,  and  the  expediency  of  creating,  or  selecting,  such 
varieties  of  different  species  of  fruits  as  are  well  adapted  to  the  present 
state  of  his  climate. 

As  the  chief  object  of  this  communication  is  to  direct  the  attention  of 
the  gardener  to  the  subject  of  fruit  trees,  I  shall  begin  my  observations 
upon  that  part  of  the  year  in  which  the  blossom- buds  of  the  succeeding 
year  are  generally  formed  and  closed  up  (though  much  change  of  struc- 
ture within  them  subsequently  takes  place),  that  is,  in  the  latter  end  of 
May.  Within  the  last  fifty  years  very  extensive  tracts  of  ground,  which 
were  previously  covered  with  trees,  have  been  cleared,  and  much  waste 
land  has  been  inclosed  and  cultivated ;  and  by  means  of  trenches  and 
ditches,  and  other  improvements  in  agriculture  and  covered  drains,  the 
water  which  falls  from  the  clouds,  and  that  which  arises  in  excess  out  of 
the  ground,  has  been  more  rapidly  and  more  efficiently  carried  off  than 
at  previous  periods.  The  quantity  of  water  which  our  rivers  contain 
and  carry  to  the  sea  in  summer  and  autumn  is,  in  consequence,  as  I  have 
witnessed  in  many  instances,  greatly  diminished  ;  and  upon  the  estate 
where  I  was  born,  and  which  I  now  possess,  my  title-deeds,  and  the  form 
of  the  ground,  prove  a  mill  to  have  stood,  in  the  reign  of  Queen  Elizabeth, 
and  probably  at  a  good  deal  later  period,  in  a  situation  to  which  sufficient 
water  to  turn  a  mill-wheel  one  day  in  a  month  cannot  now  be  obtained 
in  the  latter  part  of  the  summer  and  autumn.  Under  these  circum- 
stances the  ground  must  necessarily  become  much  more  dry  in  the  end 
of  May  than  it  could  have  been  previously  to  its  having  been  inclosed 
and  drained  and  cultivated ;  and  it  must  consequently  absorb  and  retain 
much  more  of  the  warm  summer  rain  (for  but  little  usually  flows  off) 
than  it  did  in  an  uncultivated  state  ;  and  as  water  in  cooling  is  known 
to  give  out  much  heat  to  surrounding  bodies,  much  warmth  must  be 
communicated  to  the  ground  ;  and  this  cannot  fail  to  affect  the  tempera- 
ture of  the  following  autumn.  The  warm  autumnal  rains,  in  conjunction 
with  those  of  the  summer,  must  necessarily  operate  powerfully  upon  the 
temperature  of  the  succeeding  winter  ;  and,  consistently  with  this  hypo- 
thesis, I  have  observed  that  during  the  last  forty  years,  when  the  weather 
of  the  summer  and  autumn  has  been  very  wet,  the  succeeding  winter  has 
been  in  the  climate  of  this  vicinity  generally  mild.  And  that  when 
north-east  winds  have  prevailed  after  such  wet  seasons  the  weather  in 
the  winter  has  been  cold  and  cloudy,  but  without  severe  frost,  probably 
in  part  owing  to  the  ground  upon  the  opposite  shores  of  the  Continent 
being  in  a  state  similar  to  that  on  this  side  the  Channel. 

I  was  first  led  to  notice  the  preceding  effects  by  having  observed,  many 


ON  THE  SUPPOSED  CHANGES  OF  THE  CLIMATE  OF  ENGLAND.      309 

years  ago,  that  some  trees  of  the  common  laurel,  which  grew  in  a  very 
high  and  cold  situation,  and  which  usually  lost  a  very  large  portion  of 
the  annual  wood,  in  more  than  one  winter  totally  escaped  all  injury  after 
such  wet  seasons,  though  their  annual  wood  did  not  appear  more  mature 
in  the  end  of  November,  than  it  would  have  been,  in  a  warm  and  favour- 
able situation  and  season,  in  the  end  of  July  ;  and  I  thought  the  whole 
of  it  must  have  inevitably  perished. 

Supposing  the  ground  to  contain  less  water  in  the  commencement  of 
winter,  on  account  of  the  operation  of  the  drains  above-mentioned,  as  it 
almost  always  will,  and  generally  must  do,  more  of  the  water  afforded  by 
dissolving  snows,  and  the  cold  rains  of  winter,  will  be  necessarily  absorbed 
by  it ;  and  in  the  end  of  February,  however  dry  the  ground  may  have 
been  at  the  winter  solstice,  it  will  almost  always  be  found  saturated  with 
water  derived  from  those  unfavourable  sources ;  and  as  the  influence  of 
the  sun  is  as  powerful  on  the  last  day  of  February,  as  on  the  15th  day 
of  October,  and  as  it  is  almost  wholly  the  high  temperature  of  the 
ground  in  the  latter  period  which  occasions  the  different  temperature 
of  the  air  in  those  opposite  seasons,  I  think  it  can  scarcely  be  doubted 
that  if  the  soil  have  been  rendered  more  cold  by  having  absorbed  a  larger 
portion  of  water  at  very  near  the  freezing  temperature,  the  weather  of 
the  spring  must  be,  to  some  extent,  injuriously  affected.  But  whether 
it  be  owing  to  the  preceding  or  other  causes,  I  feel  most  perfectly  confi- 
dent that  the  weather  in  the  spring  has  been  considerably  less  favourable 
to  the  blossoms  of  fruit  trees,  and  to  vegetation  generally,  during  the 
last  thirty  years,  than  it  was  in  the  preceding  period  of  the  same 
duration  ;  and  I  shall  in  conclusion  adduce  one  fact,  the  evidence  of 
which  I  think  cannot  easily  be  controverted.  The  Herefordshire  farmers 
formerly  calculated  upon  having  a  full  crop  of  acorns  upon  the  oaks, 
which  grew  dispersed  over  their  farms,  once  in  three  years  ;  but  a  good 
crop  of  acorns  is  now  a  thing  of  rare  occurrence,  upon  the  value  of  which 
the  farmer  has  almost  wholly  ceased  to  calculate,  even  upon  those  farms 
which  contain  extensive  groves  of  oaks.  The  trees  nevertheless  blossom 
annually  very  freely,  but  no  fruit  is  produced.  Many  causes  may  be 
assigned  for  the  diminished  produce  of  orchards,  and  of  fruit  trees 
generally;  but  the  blossoms  of  the  oak  must  be  now  as  capable  of 
bearing  cold  as  they  were  half-a- century  ago,  and  their  failing  to  pro- 
duce acorns  can  only  be  attributed  to  the  agency  of  some  external  cause ; 
and  I  am  wholly  unable  to  conjecture  any  such  cause  except  the  above- 
mentioned. 


310 


LXVII.— AN  ACCOUNT  OF  AN  ECONOMICAL  METHOD  OF  OBTAINING 
VERY  EARLY  CROPS  OF  NEW  POTATOES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  4th,  1830.] 

I  COMMUNICATE  the  following  account  of  a  method  of  raising  very  early 
crops  of  potatoes,  which  I  have  practised  during  the  last  two  years,  and 
which  will,  I  believe,  be  found  to  point  out  the  means  of  obtaining  that 
vegetable  at  much  less  expense  than  by  any  other  now  practised,  and  in 
a  state  of  great  perfection. 

It  is  well  known  to  every  gardener,  that  potatoes  which  have  been 
buried  sufficiently  deep  in  the  soil  to  render  them  secure  from  injury  by 
frost,  usually  vegetate  very  strongly  in  the  succeeding  spring ;  and  I  was 
thence  led  to  hope  that  by  planting  in  September  large  tubers  which  had 
ripened  early  in  the  preceding  summer,  and  had  by  a  period  of  rest 
become  excitable,  I  should  be  able  to  cause  roots  and  stems  to  be  emitted 
to  some  extent  in  the  autumn ;  and  that  these,  by  being  well  defended 
from  frost  through  winter,  might  operate  so  as  to  afford  me  a  very  early 
produce.  The  experiment  was  not  successful.  The  tubers  vegetated 
almost  immediately,  and  the  stems  just  reached  the  surface  of  the  ground, 
when  they  were  destroyed  by  frost ;  and  although  the  ground  was  imme- 
diately so  well  covered  as  securely  to  exclude  frost  from  it,  not  a  single 
plant  appeared  in  the  following  spring.  I  therefore  concluded  that  the 
experiment  had  totally  failed,  and  that  the  tubers  planted,  after  once 
vegetating,  had  perished. 

Late  in  the  following  summer,  however,  I  observed  that  a  very  large 
number  of  rather  strong  potatoe  plants  rose  through  the  soil,  precisely 
where  I  had  deposited  the  large  tubers  in  the  preceding  autumn :  and 
the  appearance  of  these  perfectly  satisfied  me  that  I  had  erred  in  sup- 
posing those  to  have  perished.  The  experiment  was  therefore  repeated 
in  the  autumn  of  1828  ;  and  the  result  in  the  succeeding  spring  was  the 
same,  not  a  single  plant  appearing  above  the  soil ;  but  upon  examination 
I  found  beneath  it,  in  June,  a  very  abundant  crop  of  excellent  young 
potatoes,  which  attained  maturity  at  least  a  month  earlier  than  those 
raised  at  the  same  time,  in  the  same  soil  and  situation,  in  the  usual  way. 
It  now  became  obvious,  that  a  similar  crop  of  young  potatoes  had  been 
produced  in  the  preceding  year ;  and  that  these,  having  remained  at  rest 
till  late  in  the  summer,  had  become  excitable,  and  had  produced  the 
numerous  plants  above-mentioned.  The  tubers  planted  were  of  the 


A    METHOD    OF    OBTAINING    EARLY    CROPS    OF    NEW    POTATOES.  311 

largest  size  which  I  could  obtain  of  the  variety,  the  ash-leaved  kidney 
potatoe. 

Similar  experiments  were  made  in  the  last  autumn ;  but  the  tempera- 
ture of  the  ground  was  so  low,  owing  to  the  excessive  coldness  of  the 
preceding  summer,  that  not  a  single  tuber  vegetated.  A  part  were 
therefore  taken  up,  and  made  to  vegetate  by  means  of  artificial  heat,  till 
they  had  emitted  stems  about  three  inches  long,  when  they  were  taken 
from  the  soil,  and  the  further  progress  of  vegetation  arrested.  In  the 
middle  of  January  these  were  put  into  a  pot  with  some  barren  sandy  soil, 
and  placed  in  the  pine-stove,  and  supplied  moderately  with  water  till  the 
middle  of  March.  At  that  period  I  discovered  that  small  new  potatoes 
had  been  abundantly  generated,  and  water  was  not  subsequently  given 
till  the  middle  of  April ;  when  I  found  the  pot  to  contain  very  well-grown 
young  potatoes,  which  were  without  any  other  defect  than  that  of  not  being, 
to  my  taste,  sufficiently  mature.  The  requisite  degree  of  artificial  heat 
to  insure  success  in  experiments  similar  to  the  preceding  may,  of  course, 
be  obtained  from  a  variety  of  different  sources,  which  I  need  not  point 
out ;  and  not  improbably,  I  think,  by  means  of  a  temperate  hot-bed,  the 
surface  of  the  mould  of  which  might  be  applied  to  other  purposes ;  but  I 
should  prefer  clean  and  barren  sand  for  the  tubers  to  be  placed  in,  as 
those  could  not  receive  early  benefit  from  a  rich  soil,  and  their  produce 
might  be  injured  in  quality. 

The  largest  crops  of  early  potatoes  will  usually  be  obtained  from  tubers 
which  have  ripened  late,  and  somewhat  imperfectly,  in  the  preceding 
year ;  but  it  is  quite  essential  to  the  success  of  the  preceding  experiment, 
that  the  tubers  which  are  planted  in  autumn  should  have  ripened  early  in 
the  foregoing  summer ;  for  otherwise  they  will  not  be  found  sufficiently 
excitable  in  autumn.  It  is  also  necessary  that  they  should  be  of  large 
size,  otherwise  the  young  potatoes  which  they  afford  will  be  small ;  and 
it  will  be  advantageous,  if  the  tubers  to  be  planted  have  been  detached 
from  their  parent  plants  upon  their  having  just  attained  their  full  growth. 

I  believe,  but  I  am  not  prepared  to  speak  upon  the  evidence  of  experi- 
ment, that  the  best  and  the  most  economical  mode  of  treating  the  old 
tubers,  after  their  progress  of  vegetation  has  been  arrested  by  cold,  will 
be  to  put  them  into  such  heaps  as  are  usually  seen  in  the  gardens  of 
cottagers,  and  to  cover  them  with  mould ;  as  a  very  large  quantity  would 
occupy  only  a  small  space,  and  their  produce  would  there  probably 
acquire  a  more  early  maturity,  and  might  be  collected  at  any  time  with 
little  trouble. 

A  writer  in  Mr.  Loudon's  Gardener's  Magazine  has  recommended  the 


312  A    METHOD    OP    OBTAINING    EAKLY    CROPS    OF    NEW    POTATOES. 

exposure  of  such  potatoes  as  are  intended  for  planting  to  the  sun,  as  soon 
as  they  acquire  their  full  growth,  till  they  attain  a  green  colour ;  and  I 
am  inclined  to  think  the  process  may  prove  in  some  degree  advantageous, 
for  the  action  of  the  sun  and  air  certainly  causes  chemical  changes  to  take 
place  in  their  component  parts  ;  and  chemical  changes  are  the  precursors 
and  concomitants  of  excitability,  if  not  the  cause  and  source  of  it.  I  am 
also  inclined  to  think  that  similar  treatment  would  be  beneficial  in  the 
culture  of  all  those  varieties  of  the  potatoe  which  do  not  naturally  vegetate 
till  late  in  the  spring. 

I  am  not  prepared  to  say  what  weight  of  new  potatoes  may  be  obtained 
from  any  given  weight  of  old ;  but  I  have  reason  to  think  that  the  young 
will  be  equal  to  the  weight  of  one-third  at  least  of  the  old ;  and  as  I 
have  shown,  in  a  communication  two  years  ago,*  that  more  than  thirty- 
five  thousand  pounds  of  our  best  and  earliest  variety  of  potatoe  now 
cultivated  may  be  obtained  from  an  acre  of  ground,  the  mode  of  culture 
recommended  will  not  be  found  expensive,  (where  artificial  heat  is  not 
employed,)  comparatively  with  the  usual  price  of  new  potatoes  early  in 
the  season.  Hogs,  if  hungry,  will  eat  the  old  tubers,  when  the  young 
have  been  taken  away  ;  but  those  probably  contain  little  nutriment,  and 
their  value  therefore  may  not  be  worth  calculating. 

Two  early  varieties  only  of  potatoe  have  been  the  subjects  of  the  above- 
stated  experiments  :  but  there  does  not  appear  any  reason  to  doubt  that 
similar  success  may  be  obtained  with  all  other  early  kinds. 


LXVIII.— AN  ACCOUNT  OF  A  METHOD  OF  OBTAINING  VERY  EARLY 
CROPS  OF  GREEN  PEAS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  \&th,  1830.] 

THERE  is  scarcely  any  vegetable  which  is  so  much  sought  after  as  the 
pea  in  its  green  state  early  in  the  season,  nor  probably  any  one,  in  the 
culture  of  which  so  much  labour  is  usually  expended  in  vain.  For  a  very 
small  portion  only  of  the  plants  obtained  from  seeds  sown  early  in  the 
autumn  survive  the  winter  and  early  spring,  and  many  of  those  which 
survive  exist  in  a  feeble  and  unhealthy  state,  and  consequently  afford  but 
a  very  small  produce.  Much  more  certain  and  abundant,  and  generally 
as  early,  crops  of  green  peas,  may  be  obtained  by  raising  the  plants  under 
glass  early  in  the  spring,  and  transferring  them  to  the  open  border  when 

*  Seep.  301. 


A    METHOD    OF.   OBTAINING    VERY    EARLY    CROPS    OF    GREEN    PEAS.         313 

they  are  about  four  or  five  inches  high.  I  have  also  raised  my  plants  in 
semi-cylindrical  tiles,  such  as  are  usually  employed  in  draining  ground,  and 
by  previously  depositing  a  little  straw  or  litter  longitudinally  upon  the 
bottoms  of  these,  I  have  been  enabled  to  slide  out  the  plants  into  the 
appointed  rows,  without  at  all  injuring  or  disturbing  their  roots.  But 
1  have  ascertained,  in  the  present  spring,  that  I  can  obtain,  by  the  fol- 
lowing means,  an  abundant  crop  of  peas  at  a  much  earlier  period  than  I 
formerly  thought  possible,  and  at  little  expense  or  trouble. 

Having  found  it  impracticable  to  raise  melons  worth  bringing  to  table 
before  the  days  become  long,  and  light  abundant,  I  never  plant  my  melon- 
seeds  till  the  end  of  February,  nor  put  the  plants  into  the  beds  or  pots  in 
which  they  are  to  remain  to  bear  fruit,  till  the  end  of  March  or 
beginning  of  April.  The  frames  and  lights  were  consequently  out  of 
employment  in  January  and  February  in  the  present  spring ;  and  I  had 
also  a  heap  of  oak-leaves  unemployed,  which  had  been  collected  for  the 
purpose  of  making  hot-beds,  and  to  which  use  they  have  subsequently 
been  applied  in  March.  With  those  a  hot-bed  was  made  in  the  middle 
of  January,  into  which  pots  of  about  nine  inches  diameter  were  placed, 
at  the  distance  of  one  foot  from  centre  to  centre.  In  each  of  these  pots 
a  couple  of  dozen  peas  were  put  in  a  circular  row ;  and  around  them  was 
planted  a  row  of  numerous  slender  twigs,  one  foot  above  the  surface  of 
the  mould.  Thus  circumstanced,  the  peas  grew  very  freely,  and  soon 
attached  themselves  by  means  of  their  tendrils  firmly  to  their  supports ; 
and  in  the  middle  of  March  they  had  become  fourteen  inches  high,  and 
nearly  in  contact  with  the  glass  roof,  which  had  been  previously  raised  a 
little.  They  were  then  transferred  to  the  open  border,  and  some  manure 
was  given,  and  very  numerous  sticks  were  employed  to  afford  them  some 
degree  of  protection.  This  transplantation  and  removal  from  the  pots  did 
not  appear  to  injure  them  in  any  degree  ;  and  in  the  end  of  March  many  of 
their  blossoms  were  so  far  advanced  that  they  had  shed  their  pollen.  On 
the  second  day  of  April  a  frost  of  almost  unprecedented  severity 
occurred,  having  been  preceded  by  an  incessant  fall  of  snow  of  forty 
hours'  duration;  and  I  anticipated  the  total  destruction  of  my  crop  of  peas. 
I  was,  however,  very  agreeably  disappointed  in  finding  that  little  or  no 
greater  injury  had  been  sustained  by  plants  of  sixteen  than  by  those  of 
four  inches  high :  and  on  the  26th  of  April,  when  I  last  saw  them,  they 
were  at  least  three  weeks  earlier  than  any  I  had  ever  previously  been 
able  to  raise  ;  and  that,  in  a  high  and  cold  situation,  some  of  the  pods 
were  above  an  inch  and  a  half  long. 

An  interval  of  nine  inches  was  left  between  each  pot  of  plants,  which 


314  A     METHOD    OF    OBTAINING    VERY    EARLY    CROPS    OF    GREEN    PEAS. 

intervals  soon  ceased  to  be  visible ;  and  a  prospect  of  an  abundant  crop 
was  afforded.  I  therefore  conceive  myself  to  have  raised  an  exceedingly 
early  and  valuable  crop  of  peas,  without  any  loss  of  time  to  my  melons ; 
plants  of  which,  of  proper  size  and  age,  .and  growing  in  pots,  had  been 
made  ready  to  occupy  the  frames  whence  the  peas  were  taken. 


LXIX.— UPON    THE    CULTIVATION    OF   THE    PERSIAN  VARIETIES    OF 

THE    MELON. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  Isi,  1831.] 

I  SENT  to  the  Horticultural  Society,  in  the  last  season,  a  couple  of 
Ispahan  Melons  ;  one  in  August,  which,  I  had  the  pleasure  to  hear  was 
thought  very  excellent  :  and  the  other  (which  did  not  ripen  till  the  latter 
end  of  October)  not  more  inferior  than  might  have  been  anticipated,  on 
account  of  the  diminished  powers  of  the  sun  in  the  latter  period.  Both 
were  the  produce  of  very  ill-treated  plants  :  but  both  had  the  advan- 
tages of  very  excellent  machinery  ;  and  the  effects  of  the  management 
were  so  singular,  that  a  statement  of  them  may  prove  alike  interesting  to 
the  mere  practical,  and  to  the  physiological  horticulturist 

Having,  during  several  years,  observed,  that  fine  Persian  melons  were 
preferred  at  my  table  to  almost  every  other  species  of  fruit,  I  was  led  to 
erect,  early  in  the  last  spring,  a  small  forcing-house  for  the  almost  exclusive 
culture  of  them,  and  by  means  of  heat  obtained  from  fire  only,  under  an 
impression  that  in  some  seasons  and  states  of  the  weather,  the  power  of 
commanding  a  dry  atmosphere,  and  high  temperature,  would  prove  highly 
beneficial  to  the  quality  of  the  fruit.  This  forcing-house  consists  of  a 
back  wall  nearly  nine  feet  high,  and  of  a  front  wall  nearly  six  feet  high, 
inclosing  a  horizontal  space  of  nine  feet  wide  ;  and  the  house  is  thirty 
feet  long.  It  might  as  well  have  been  forty  feet  long  ;  but  the  smaller 
size  was  sufficient  for  my  purpose.  The  fire-place  is  at  the  east  end,  very 
near  the  front  wall,  and  the  flue  passes  to  the  other  end  of  the  house 
within  four  inches  of  the  front  wall,  and  returns  back  again,  leaving  a 
space  of  eight  inches  only  between  the  advancing  and  returning  course  of 
it;  and  the  smoke  escapes  at  the  north-east  corner  of  the  building.  The 
front  flue  is  composed  of  bricks  laid  flat,  as  I  wished  to  have  a  temperate 
permanent  heat,  and  the  returning  flue  of  bricks  standing  on  their  edges', 
as  is  usual ;  the  space  between  the  flues  is  filled  with  fragments  of  burned 
bricks,  which  absorb  much  water,  and  gradually  give  out  moisture  to  the 


ON    THE    CULTIVATION    OF   THE    PERSIAN    VARIETIES    OF    THE    MELON. 

air  of  the  house.  Air  is  admitted  through  apertures  in  the  front  wall, 
which  are  four  inches  wide,  and  nearly  three  in  height ;  and  which  are 
situated  level  with  the  top  of  the  flues,  and  are  eighteen  inches  distant 
from  each  other.  The  air  escapes  through  similar  apertures  near  the  top 
of  the  back  wall.  These  apertures  are  left  open,  or  partially  or  wholly 
closed,  as  circumstances  require.  Thirty-two  pots  are  placed  upon  the 
flues  described  above,  each  being  sixteen  inches  wide  at  least,  and  four- 
teen inches  deep ;  but  they  are  raised  by  an  intervening  piece  of  stone 
and  brick  out  of  actual  contact  with  the  flues.  Into  each  of  these  pots 
one  melon  plant  is  put,  which  in  its  subsequent  growth  is  trained  upon  a 
trellis  placed  about  fourteen  inches  distant  from  the  glass,  and  each 
plant  is  permitted  to  bear  one  melon  only.  Each  might  be  made  to  bear 
more,  but  if  they  should  be  as  large  as  Ispahan  melons  are  when  perfect, 
they  would  certainly  be  of  inferior  quality.  The  height  from  the  ground 
at  which  the  trellis  is  placed  is  such  that  I  can  with  convenience  walk 
under  it,  and  of  course  discover  without  difficulty  the  first  appearance  of 
red  spiders,  or  other  noxious  insects. 

When  I  left  the  country  to  come  to  London  in  the  last  spring,  my 
plants  were  growing  most  luxuriantly ;  and  their  appearance  was  every- 
thing that  I  wished.  But  during  my  absence  a  few  red  spiders 
appeared  upon  one  of  the  plants,  as  I  had  anticipated,  and  my  gardener, 
in  consequence,  and  in  obedience  to  my  instructions,  sprinkled  the  under 
surfaces  of  the  leaves  frequently,  and  rather  freely,  with  water.  By  these 
measures  the  increase  and  spreading  of  the  red  spider  was  effectually 
prevented  ;  but  on  my  return  from  London,  I  found  that  my  plants  had 
wholly  ceased  to  grow,  though  their  appearance  was  healthy  ;  and  subse- 
quently all  the  fruit  dropped  off*  either  before  or  soon  after  their  blossom 
had  expanded.  I  in  consequence  immediately  ordered  other  plants  to  be 
raised,  still,  however,  entertaining  hopes  of  preserving  those  I  had.  But 
those  hopes  were  not  realised ;  and  I  was  obliged  to  throw  away  the 
whole  of  them,  with  the  exception  of  one,  which  was  more  healthy  than 
the  others,  and  which  lived  to  produce  the  first  fruit  sent  to  the  Society. 
That  appeared  to  be,  as  it  proved,  of  good  quality ;  but  it  was  defective 
in  size ;  its  weight  seemed  little,  if  anything,  more  than  five  pounds. 

My  second  family  of  plants  were  treated  nearly  as  the  first  had  been, 
and  with  the  same  approaching  results ;  but  I  was  led  by  the  discoveries 
of  M.  Dutrochet  to  change  my  mode  of  management,  and,  I  believe,  to 
discover  the  cause  of  the  preceding  failure.  This  eminent  physiologist 
had  discovered  that  if  a  lighter  fluid  be  in  contact  with  one  side  of  an 
animal  or  vegetable  membrane,  and  a  denser  fluid  with  the  opposite  side, 


316      ON    THE    CULTIVATION    OF    THE    PERSIAN    VARIETIES    OF    THE    MELON. 

the  lighter  fluid  will  rush  into  the  denser  through  the  membrane,  though 
that  be  under  other  circumstances  impervious  to  it.  The  force  with  which 
the  lighter  fluid,  in  some  of  the  experiments  of  M.  Dutrochet,  rushed 
through  animal  membranes  into  the  denser,  appears  to  be  exceedingly 
wonderful.  He  found,  that  under  such  circumstances  water  would  pass 
upwards  through  three  folds  of  the  substance  of  a  recently-extracted 
animal  bladder,  and  in  opposition  to  the  perpendicular  pressure  of  forty- 
five  inches  of  quicksilver ;  which  is  nearly  equivalent  to  a  pressure  of 
twenty-two  and  a  half  pounds  upon  a  square  inch  of  surface.  This  power 
in  vegetable  membranes  to  transmit  the  lighter  into  the  denser  fluid  is, 
I  think,  probably  in  active  operation  during  the  ascent  of  the  sap  of  trees 
in  the  spring  ;  for  it  is  through  the  cellular  substance,  and  not  through 
the  tubes  of  the  alburnum,  that  the  sap  ascends,  or  its  ascent  would  be 
prevented,  which  it  is  not,  by  intersection  of  those  tubes ;  and  those  tubes 
are  also  dry  at  midsummer,  when  the  sap  is  rising  to  supply  moisture  to 
the  leaves  in  great  abundance.  Previously  to  the  discoveries  of  M. 
Dutrochet,  I  had  shown  that  the  sap  of  trees  is  lightest,  or  least  dense, 
near  the  ground  ;  and  that  in  any  particular  tree,  the  weight  of  the  sap 
increases  as  its  distance  from  the  ground  through  the  course  of  the  albur- 
num increases :  and  I  had  also  proved  that  saccharine  matter  exists  in 
considerable  quantity  in  the  sap  in  the  spring,  in  cases  where  no  vestige 
of  it  can  be  discovered  in  winter :  and  sugar  was  the  material  employed 
by  M.  Dutrochet  to  form  his  denser  fluid.  These  facts  were  not  in  any 
degree  known  to  M.  Dutrochet  when  he  made  his  discoveries,  and  he 
therefore  was  certainly  not  led  in  any  degree  by  me  in  making  them. 

The  sap  in  the  leaves  of  my  melon  plants  was  certainly  a  denser  fluid 
than  the  water  with  which  they  were  sprinkled  ;  and  therefore  I  imagine 
that  the  latter  fluid  passed  in  injurious  excess  into  the  cells  and  vessels, 
and  that  the  ingress  and  circulation  of  the  proper  fluid,  which  ought  to 
have  continued  to  ascend  from  the  roots,  was  to  a  great  extent  prevented, 
and  that  the  creation  of  the  true  or  living  sap  of  the  plant  almost  wholly 
ceased.  The  plant  consequently,  I  conclude,  ceased  to  grow,  and  the  fruit 
fell  off,  owing  to  want  of  proper  nutriment.  Soon  after  I  had  ceased  to 
sprinkle  the  under  surfaces  of  the  leaves,  the  young  fruit  began  to  set 
well,  and  the  plants  to  grow,  but  never  with  very  great  vigour  ;  and  the 
fruit,  though  its  quality  was  exceedingly  good,  was  smaller  a  good  deal 
than  I  conceived  it  would  have  been  if  the  under  sides  of  the  leaves  had 
not  been  so  frequently  wetted.  The  weather  was,  however,  very  unfa- 
vourable, and  the  fruit,  I  entertain  no  doubt,  would  have  been  larger,  if 
the  foliage  of  these  plants  had  received  the  benefit  of  more  light.  I  have 


ON    THE    CULTIVATION    OF    THE    PERSIAN     VARIETIES    OF    THE    MELON.     317 

mentioned,  in  a  former  communication  upon  the  culture  of  the  melon,  that 
a  single  melon  .or  gourd  will  put  in  requisition,  during  the  period  of  its 
rapid  growth,  the  services  of  the  most  distant  leaf,  and  cause  the  most 
distant  blossom  to  fall  off  abortively.  But  I  was,  at  that  period,  wholly 
unprepared  to  offer  any  conjecture  whatever  respecting  the  power  by 
which  the  sap  generated  in  very  distant  leaves  could  be  conveyed  to  the 
extent  indicated  to  the  fruit. 

The  above  mentioned  discoveries  of  M.  Dutrochet  appear  to  me  to 
have  thrown  some  light  upon  this  mysterious  point ;  for  if  the  fluid  within 
the  fruit  be  denser  than  that  in  the  leaves  and  stems,  (and  in  certain 
states  at  least  of  the  growth  of  the  fruit  it  certainly  is  so,)  the  lighter 
fluid  must  rush  into  the  denser ;  and  that  the  sap  flows  in  very  large 
quantity  into  the  growing  melon,  can  I  think  scarcely  be  doubted.     I  am 
well  satisfied  that  a  very  large  quantity  of  the  sap  of  the  plant,  or  more 
properly  of  the  aqueous  part  of  that  fluid,  passes  through  the  fruit  into 
the  vessels  of  the  plant  again  ;  but  by  what  means  it  can  be  propelled,  I 
am  wholly  at  a  loss  to  conjecture.     Much  must,  I  conceive,  be  done  by 
some  operation  of  the  fruit  itself;  for  it  is  totally  absurd  to  suppose  that 
a  distant  leaf  can,  by  any  mode  of  action  properly  its  own,  cause  the  true 
sap  which  it  generates,  to  flow  to  and  into  the  fruit.     Previously  to  the 
maturity  of  my  late  crop  of  melons,  I  had  prepared  some  strong  cucum- 
ber plants,  which  I  had  protected  from  the  frost ;  and  these  being  brought 
into  the  place  whence  the  melon  plants  had  been  taken,  afforded  me  a 
crop  of  fine  cucumbers  in  November  and  December.     I  have  now  cucum- 
ber plants  growing  in  great  health  and  vigour,  from  which  I  do  not 
entertain  any   doubt  of  obtaining  an  abundant  crop  of  cucumbers   in 
March  and  the  beginning  of  April,  when  it  is  my  intention  to  introduce 
strong  Ispahan  melon  plants  ;  and   I  feel  confident  that,  by  having  a 
proper  plant  ready  to  supply  the  place  of  every  one  which  affords  a  ripe 
fruit,  I  shall  be  able  to  obtain  two  abundant  crops  of  excellent  melons 
within  the  same  season*,     if  these  expectations  should  prove  to  be  well 
founded,  I  conceive  that  forcing-houses,  such  as  I  have  described,  for  the 
culture  of  very  early  cucumbers  and  Persian  melons,  might  be  erected  with 
advantage  in  those  districts  in  which  coals  are  raised ;  for  the  dust  of 
coals  is  all  that  is  wanted,  and  in  fact  is  preferable;  and  cucumbers  can 
be  sent  to  a  very  considerable  distance  without  suffering  much,  and  melons 
without  suffering  any  deterioration. 

The  best  varieties  of  Persian  melons  are,  I  believe,  very  subject  to 
burst  when  raised  in  this  country  ;  and  I  imagine  that  they  very  frequently 

*  I  shall  obtain  three  successions  in  the  present  season. 


318     ON    THE    CULTIVATION    OF    THE    PERSIAN    VAUIETIES    OF    THE    MELON. 

do  so  in  their  native  country  ;  for  Sir  Harford  Jones  Brydges  informed 
me,  that  he  had  heard  the  Persian  gardeners  express  fear  when  a  horse 
was  ridden  at  a  rapid  pace  near  the  melon  beds,  that  the  vibration  of  the 
soil  would  cause  the  melons  to  burst.  It  occurred  to  me  in  the  last  sum- 
mer, that  melons  might  possibly  be  made  more  safe  from  accidents  of  this 
kind,  if  I  raised  their  points  higher  than  their  stems,  and  thus  caused 
gravitation,  which  operates  very  powerfully  upon  the  form  and  growth  of 
plants,  to  assist  in  carrying  away  any  excess  of  fluid,  which  the  fruit, 
from  any  cause,  might  happen  at  any  period  to  contain.  I  consequently 
gave  to  every  melon  an  elevation  of  thirty  degrees,  and  not  one  of  those 
failed  to  ripen  in  a  whole  and  perfect  state  ;  but  whether  owing  to  any 
action  of  gravitation  or  not,  I  am,  of  course,  unprepared  to  decide  :  the 
experiment,  however,  appears  worth  repeating.  I  suspect  melons  fre- 
quently burst  owing  to  the  injurious  effects  of  the  pressure  of  their  weight 
upon  their  lower  sides;  for  when  I  have  suffered  them  to  hang  down 
perpendicularly,  they  have  always  ripened  well ;  but  the  Ispahan  melons, 
under  such  circumstances,  assumed  forms  nearly  similar  to  those  of 
cucumbers  swollen  at  their  points,  and  such  forms  are  to  my  eyes  very 
unpleasing. 


LXX.— ON   THE    POTATOE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  }st,  1831.] 

IF  the  potatoe  could  only  be  employed,  as  it  has  chiefly  been,  to  afford 
vegetable  food  to  mankind,  its  improvement  would  be  an  exceedingly 
important  object ;  for,  circumstanced  as  this  country  is,  it  must  neces- 
sarily constitute  a  large  part  of  the  food  of  the  poorer  classes  ;  and  it  is 
consumed  in  large  quantities  at  the  tables  of  the  affluent  and  luxurious. 
But  I  am  convinced,  by  the  evidence  of  experiments  which  I  have  been 
some  years  in  making,  that  the  potatoe  plant,  under  proper  management,  is 
capable  of  causing  to  be  brought  to  market  a  much  greater  weight  of  vege- 
table food,  from  any  given  extent  of  ground,  than  any  other  plant  which 
we  possess,  with  equal  profit  to  the  farmer.  The  Swedish  turnip  may, 
in  certain  seasons  and  when  the  soil  is  favourable,  rival,  and  perhaps 
excel  it ;  but  a  total  failure  of  crops  of  that  plant  is  an  event  of  no 
unfrequent  occurrence,  and  partial  failures  occur  in  almost  every  season; 
whilst  by  proper  culture,  and  selection  of  varieties  which  vegetate  and 


ON    THE    POTATOE.  319 

acquire  maturity  in  successive  parts  of  summer  and  autumn,  there  is  not 
any  crop  which  I  conceive  to  be  so  certain  as  that  of  potatoes  ;  and  it 
has  the  advantage  of  being  generally  most  abundant,  when  the  crops  of 
wheat  are  defective :  that  is,  in  wet  seasons  *.  And,  I  think,  I  shall  be 
able  to  adduce  some  strong  facts  in  support  of  my  opinion,  that  by  a 
greatly  extended  culture  of  the  potatoe,  for  the  purpose  of  supplying  the 
markets  with  vegetable  food,  a  more  abundant  and  more  wholesome 
supply  of  food  for  the  use  of  the  labouring  classes  of  society  may  be 
obtained  than  wheat  can  ever  afford,  and,  I  believe,  of  a  more  palatable 
kind  to  the  greater  number  of  persons.  I  can  just  recollect  the  time 
when  the  potatoe  was  unknown  to  the  peasantry  of  Herefordshire,  whose 
gardens  were  then  almost  exclusively  occupied  by  different  varieties  of 
the  cabbage.  Their  food  at  that  period  chiefly  consisted  of  bread  and 
cheese,  with  the  produce  of  their  gardens,  and  tea  was  unknown  to  them. 
About  sixty-six  years  ago,  before  the  potatoe  was  introduced  into  their 
gardens,  agues  had  been  so  extremely  prevalent,  that  the  periods  in 
which  they,  or  their  families,  had  been  afflicted  with  that  disorder,  were 
the  eras  to  which  I  usually  heard  them  refer  in  speaking  of  past  events ; 
and  I  recollect  being  cautioned  by  them  frequently  not  to  stand  exposed 
to  the  sun  in  May,  lest  I  should  get  an  ague.  The  potatoe  was  then 
cultivated  in  small  quantities  in  the  gardens  of  gentlemen  ;  but  it  was 
not  thought  to  afford  wholesome  nutriment,  and  was  supposed  by  many 
to  possess  deleterious  qualities.  The  prejudices  of  all  parties,  however, 
disappeared  so  rapidly,  that  within  ten  years  the  potatoe  had  almost 
wholly  driven  the  cabbage  from  the  garden  of  the  cottagers.  Within 
the  same  period,  ague,  the  previously  prevalent  disease  of  the  country, 
disappeared ;  and  no  other  species  of  disease  became  prevalent.  I 
adduce  this  fact,  as  evidence  only,  that  the  introduction  of  the  potatoe 
was  not  injurious  to  the  health  of  the  peasantry  at  that  period  ;  but 
whether  its  production  was,  or  was  not,  instrumental  in  causing  the 
disappearance  of  ague,  I  will  not  venture  to  give  an  opinion.  I  am, 
however,  confident,  that  neither  draining  the  soil  (for  that  was  not  done), 
nor  any  change  in  the  general  habits  of  the  peasantry,  had  taken  place, 
to  which  their  improved  health  could  be  attributed. 

Bread  is  well  known  to  constitute  the  chief  food  of  the  French 
peasantry.  They  are  a  very  temperate  race  of  men ;  and  they  possess 

*  Failures  of  crops  of  potatoes  occur  in  Ireland,  because  the  excessive  poverty  of  the 
peasantry  compels  them  to  plant  their  ground  generally  with  less  than  one-fifth  of  the  proper 
quantity  of  potatoes  ;  and  all  the  Irish  varieties  which  I  have  seen  have  been  unproductive, 
though  generally  of  exceedingly  good  quality ;  the  Irish  mode  of  culture  is  also,  I  have  reason 
to  believe,  excessively  bad. 


320  ON    THE    POTATOE. 

the  advantages  of  a  very  fine  and  dry  climate.  Yet  the  duration  of 
life  amongst  them  is  very  short,  scarcely  exceeding  two-thirds  of  the 
average  duration  of  life  in  England,  and  in  some  districts  much  less. 
Dr.  Hawkins,  in  his  Medical  Statistics,  states  upon  the  authority  of 
M.  Villerme,  that  in  the  department  of  Indre,  "  one-fourth  of  the 
children  born  die  within  the  first  year,  and  half  between  fifteen  and 
twenty,  and  that  three-fourths  are  dead  within  the  space  of  fifty  years.11 
Having  inquired  of  a  very  eminent  French  physiologist,  M.  Dutrochet, 
who  is  resident  in  the  department  of  Indre,  the  cause  of  this  extraor- 
dinary mortality,  he  stated  it  to  be  their  food,  which  consisted  chiefly  of 
bread ;  and  of  which  he  calculated  every  adult  peasant  to  eat  two  pounds 
a  dav.  And  he  added,  without  having  received  any  leading  question 
from  me,  or  in  any  degree  knowing  my  opinion  upon  the  subject,  that  if 
the  peasantry  of  his  country  would  substitute  (which  they  could  do)  a 
small  quantity  of  animal  food  with  potatoes  instead  of  so  much  bread, 
they  would  live  much  longer,  and  with  much  better  health.  I  am 
inclined  to  pay  much  deference  to  M.  Dutrochet's  opinion  ;  for  he  com- 
bines the  advantages  of  a  regular  medical  education  with  great  acuteness 
of  mind,  and  I  believe  him  to  be  as  well  acquainted  with  the  general  laws 
of  organic  life  as  any  person  living :  and  I  think  his  opinion  deserves 
some  support  from  the  well  known  fact,  that  the  duration  of  human  life 
has  been  much  greater  in  England  during  the  last  sixty  years  than  in  the 
preceding  period  of  the  same  duration.  Bread  made  of  wheat,  when 
taken  in  large  quantities,  has  probably,  more  than  any  other  article  of 
food  in  use  in  this  country,  the  effect  of  overloading  the  alimentary 
canal ;  and  the  general  practice  of  the  French  physicians  points  out  the 
prevalence  of  diseases  thence  arising  amongst  their  patients. 

I  do  not,  however,  think  or  mean  to  say,  that  potatoes  alone  are 
proper  food  for  any  human  being  :  but  I  feel  confident,  that  four  ounces 
of  meat,  with  as  large  a  quantity  of  good  potatoes  as  would  wholly  take 
away  the  sensation  of  hunger,  would  afford,  during  twenty-four  hours, 
more  efficient  nutriment  than  could  be  derived  from  bread  in  any 
quantity,  and  might  be  obtained  at  much  less  expense. 

I  now  proceed  to  give  an  account  of  the  result  of  the  experiment  above- 
mentioned,  which,  I  hope,  will  be  found  sufficiently  interesting  to  attract 
the  attention  of  the  Members  of  this  Society.  It  has  been  proved  by 
many  other  persons,  as  well  as  by  myself,  that  if  all  the  blossoms  of  a 
potatoe  plant  be  picked  off,  as  soon  as  they  become  visible,  the  quantity 
of  tubers  will  be  considerably  increased,  particularly  if  the  variety  be 
one  which  produces  seeds  ;  and  I  have  shown  that  the  cause  why  early 


ON    THE    POTATOE.  321 

varieties  of  the  potatoe  do  not   afford  blossoms  is  the  preternaturally 
early  disposition  of  the  plant  to  generate  its  tuberous  roots.     The  early 
varieties  are  of  dwarfish  growth,  and  therefore  improper  for  extensive 
field  culture;  but  I  have  found  that  by  cross-breeding  between  those, 
and  varieties  of  tall  and  luxuriant  growth,  I  can  communicate  to  the 
latter  the  habit  of  producing  tubers  only,  without  blossom  ;  with,  I  have 
reason  to  hope,  considerable  advantages.     I  now  possess  a  good  many  of 
such  varieties,  selected  from  a  very  great  number,  which  prove  totally 
worthless ;  but  many  of  those  varieties  which  do  not  produce  blossom, 
have  other  defects,  which  render  them  of  little  value.     The  stems  of  some 
of  these  are  not  strong  and  rigid  enough  to  support  themselves  and  their 
foliage  ;  and  they  are  consequently  beaten  down  by  rain  and  winds.    The 
foliage  of  one  stem  consequently  often  becomes  so  placed  as  to  shade  the 
foliage  of  another ;  and  as  the  whole  material  of  the  tubers  is  formed  of 
living  matter,  which  is  generated  in  the  leaves  only,  and  as  all  leaves 
which  are  shaded  become  inefficient  and  useless,  a  sufficient  degree  of 
strength  and  rigidity  in  the  stems  to  enable  them  to  retain  their  foliage 
in  its  first  position  is  very  important ;  though  I  believe  that  this  circum- 
stance has  not  hitherto  attracted  the  attention  of  any  cultivator  of  the 
potatoe. 

The  tubers  of  other  varieties,  which  were  in  all  other  respects  appa- 
rently good,  were  defective  in  specific  gravity,  and  consequently  aqueous 
and  worthless;  and  in  others,  veins  of  a  red  colour  extended  in  to  the  body 
of  the  tubers,  and  gave  an  unpleasant  colour  to  their  meal,  which  was  in 
some  other  respects  of  very  good  quality.  But  I  have  obtained  several 
varieties  which  do  not  blossom,  and  which  are,  as  far  as  I  am  at  present 
capable  of  judging,  without  any  particular  defect ;  though  I  am  far  from 
thinking  I  possess  any  variety  which  has  even  approximated  to  the 
greatest  state  of  perfection  which  the  species  is  capable  of  attaining. 

I  have  succeeded  in  obtaining,  as  I  wished,  some  varieties  which  vege- 
tate early,  and  others  late,  in  the  spring.  Those  of  the  first-mentioned 
habit  will  generally  be  found  to  afford  the  largest  produce  by  having  the 
advantages  of  a  longer  summer ;  but  it  is  desirable  to  possess  varieties  of 
less  excitable  habits,  because  such  usually  remain  good  till  a  later  period 
in  the  spring,  when  good  vegetables  are  not  always  readily  obtainable. 
I  have  also  succeeded  in  obtaining  varieties  which  do  not  vegetate  till 
late  in  the  spring,  and  which,  nevertheless,  acquire  perfect  or  rather 
early  maturity  in  autumn,  and  there  are  probably  climates  in  which  such 
varieties  would  be  peculiarly  valuable ;  and  the  ductility  and  obedience 
of  this  species  of  plant  to  human  will  is  so  great,  that  I  doubt  whether, 


322  ON    THE    POTATOE. 

by  the  creation  and  selection  of  proper  varieties,  as  abundant  a  produce 
might  not  be  obtained  within  the  limits  bf  the  frigid  zone  as  in  the  torrid 
zone,  of  which  the  potatoe  is  a  native.  The  weather  in  some  parts  of 
the  coast  of  Norway,  within  the  limits  of  the  frigid  zone,  is  very  warm 
and  bright  during  a  period,  which  I  believe  to  be  quite  long  enough  to 
ripen  any  early  variety  of  the  potatoe  perfectly. 

It  is  my  wish  to  send  in  the  spring  one  or  two  potatoes  of  each  of  the 
varieties  which  I  think  likely  to  prove  valuable ;  and  I  shall  be  happy 
subsequently  to  send  a  quantity  of  any  which  may  be  approved. 

In  raising  varieties  of  the  potatoe  from  seeds  it  is  always  expedient  to 
use  artificial  heat.  I  have  trained  up  a  young  seedling  plant  in  a  some- 
what shaded  situation  in  the  stove  till  it  has  been  between  four  and  five 
feet  high,  and  then  removed  it  to  the  open  ground  in  the  beginning  of 
May,  covering  its  stem  during  almost  its  whole  length  lightly  with  mould, 
and  by  such  means  I  have  obtained  within  the  first  year  nearly  a  peck  of 
potatoes  from  a  single  plant.  But  I  usually  sow  the  seeds  in  a  hotbed 
early  in  March,  and,  after  having  given  them  one  transplantation  in  the 
hotbed,  I  have  gradually  exposed  them  to  the  open  air,  and  planted  them 
out  in  the  middle  of  May  :  and,  by  immersing  their  stems  rather  deeply 
into  the  ground,  I  have  within  the  same  season  usually  seen  each  variety 
in  such  a  state  of  maturity  as  has  enabled  me  to  judge,  with  a  good  deal 
of  accuracy,  respecting  its  future  merits. 

I  stated,  in  a  former  communication  two  years  ago,  that  I  had  obtained 
from  a  small  plantation  of  the  early  ash-leaved  kidney  potatoe  a  produce 
equivalent  to  that  of  665  bushels,  of  80  pounds  each,  per  acre  ;  and  my 
crop  of  that  variety  in  the  present  year  was  to  a  small  extent  greater. 
By  a  mistake  of  my  workmen  I  was  prevented  ascertaining  with 
accuracy  the  produce  per  acre  of  a  plantation  of  Lankman's  potatoe  ; 
but  one  of  my  friends  having  made  a  plantation  of  that  variety  precisely 
in  conformity  with  the  instructions  given  in  my  former  communication 
to  this  society,  I  requested  that  he  would  send  me  an  accurate  account 
of  the  produce ;  which  I  have  reason  to  believe  he  did,  for  its  amount 
very  nearly  agreed  with  my  calculation  upon  viewing  the  growing  crop 
about  six  weeks  before  it  was  collected.  The  situation  in  which  this  crop 
grew  was  high  and  cold,  and  the  ground  was  not  rich,  but  the  part  where 
the  potatoes  to  be  weighed  were  selected  was  perfectly  dry,  and  afforded 
a  much  better  crop  than  the  remainder  of  the  field  ;  which  was  planted 
with  several  different  varieties.  I  calculated  the  produce  of  the  selected 
part  to  be  600  bushels  per  acre,  and  the  report  I  received,  and  which  I 
believe  to  have  been  perfectly  accurate,  stated  it  to  be  628.  If  this 


ON    THE    POTATOE.  323 

produce  be  eaten  by  hogs,  or  cows,  or  sheep  (for  all  are  equally  fond  of 
potatoes),  I  entertain  no  doubt  whatever  that  it  will  afford  twenty  times 
as  much  animal  food  as  the  same  extent  of  the  same  ground  would  have 
yielded  in  permanent  pasture ;  and  I  am  perfectly  satisfied  upon  the 
evidence  of  facts  which  I  have  recently  ascertained  that,  if  the  whole  of 
the  manure  afforded  by  the  crops  of  potatoes  above-mentioned  be  returned 
to  the  field,  it  will  be  capable  of  affording  as  good,  and  even  a  better, 
crop  in  the  present  year  than  it  did  in  the  last ;  and  that  as  long  a 
succession  of  at  least  equally  good  crops  might  be  obtained  as  the  culti- 
vator might  choose,  and  with  benefit  to  the  soil  of  the  field.  Should  this 
conclusion  prove  correct,  a  very  interesting  question  arises,  viz. — whether 
the  spade  husbandry  might  not  be  introduced  upon  a  few  acres  of  ground 
surrounding,  on  all  sides,  the  cottages  of  day-labourers,  to  and  from  every 
part  of  which  the  manure  and  the  produce  might  be  conveyed  without 
the  necessity  of  a  horse  being  ever  employed.  A  single  man  might  easily 
manage  four  statute  acres  thus  situated,  with  the  assistance  of  his  family  ; 
and  if  nothing  were  taken  away  from  the  ground  except  animal  food,  I 
feel  confident  that  the  ground  might  be  made  to  become  gradually  more 
and  more  productive,  with  great  benefit  to  the  possessor  of  the  soil,  and 
to  the  labouring  classes,  wherever  the  supply  is  found  to  exceed  the 
demand  for  labour. 


LXXI.— ON  THE  MEANS  OF  PROLONGING  THE    DURATION    OF  VALUABLE 
VARIETIES    OF   FRUITS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  May  3rd,  1831.] 

THE  fact  that  all  trees  of  the  same  variety  of  fruit,  where  each  tree 
partakes  necessarily  of  one  common  life,  are  in  their  habits  strongly 
connected  with  those  of  the  first  original  tree  of  the  variety,  is,  I  think, 
placed  beyond  the  reach  of  controversy.  None  can  be  made  to  produce 
blossoms  or  fruit  till  the  original  tree  has  attained  its  age  of  puberty ; 
and,  under  our  ordinary  modes  of  propagation  by  grafts  and  buds,  all 
become  subject  within  no  very  distant  period  to  the  debilities  and  diseases 
of  old  age.  It  is  therefore  desirable  that  the  planter  should  know  at 
what  periods  of  their  existence  varieties  of  fruits  are  most  productive  and 
eligible ;  and  by  what  means  (if  any  exist)  the  deterioration  of  valuable 
varieties  may  be  prevented  or  retarded.  I  was  formerly  inclined  to 
believe  that  grafts  taken  from  very  young  seedling  trees,  as  soon  as  the 

Y2 


324  ON    PROLONGING    THE    DURATION    OF    VARIETIES    OF    FRUITS. 

qualities  of  their  produce  could  be  known,  would  show  more  disposition 
to  grow  than  to  produce  fruit,  and  I  had  previously  satisfied  myself  that 
the  blossoms  of  old  and  debilitated  varieties  of  fruits  were  extremely 
impatient  of  cold  and  unfavourable  weather ;  and  I  was  thence  led  to 
infer  that  each  variety  possessed  its  greatest  value  in  its  middle  age. 
But  subsequent  experiment  and  observation  have  compelled  me  to  draw 
a  different  conclusion ;  and  I  believe  that  in  vegetable,  as  in  animal  life, 
the  most  prolific  period  is  that  which  immediately  succeeds  the  age  of 
puberty. 

I  have  made  a  good  many  experiments  with  a  view  of  ascertaining  this 
point,  of  which  the  following  are  amongst  the  most  satisfactory.  I  took 
in  the  summer  of  1828  some  buds  from  the  extremities  of  the  leading 
branches  of  seedling  pear-trees,  which,  being  nearly  twenty  years  old, 
had  in  the  preceding  autumn  produced  their  first  fruit.  The  buds 
were  in  July  inserted  in  stocks,  which  had  sprung  from  seeds  in  the 
preceding  spring,  and  were  then  only  four  months  old.  The  trees  are 
consequently  three  years  old  now,  dating  from  the  period  when  they 
sprang  from  the  ground  ;  and  many  of  them,  though  they  have  not  been 
transplanted  or  subjected  to  any  peculiar  mode  of  treatment,  have 
produced  blossoms,  some  of  them  very  abundantly  and  vigorously,  in  the 
present  spring.  I  never  previously  saw,  and  I  do  not  think  that  any 
other  person  has  seen,  in  this  climate  fruit  produced  by  pear-trees  at  so 
early  an  age.  I  had  previously  made  the  same  experiment  with  apple- 
trees  with  the  same  results. 

Some  branches  of  a  plum-tree  which  had  not  attained  the  age  of 
puberty  were  employed  as  layers,  and  these,  as  I  expected  they  would, 
very  freely  emitted  roots ;  but,  very  contrary  to  my  expectations,  I  found 
that  the  young  shoots  which  these  layers  had  produced  afforded  in  the 
following  spring  much  blossom.  The  variety  of  plum  which  was  the 
subject  of  this  experiment  is,  I  have  reason  to  believe,  exceedingly 
productive  of  blossom ;  but  I  doubt  much  whether  such  blossoms  would 
have  appeared  if  the  variety  had  been  a  century  old.  The  only  inference, 
however,  which  I  wish  to  draw  from  the  foregoing  premises  is,  that  grafts 
or  buds  taken  from  the  bearing  branches  of  very  young  seedling  trees 
afford  trees  capable  of  bearing  freely  at  a  very  early  age;  as  it  would  be 
waste  of  time  to  offer  facts  or  arguments  in  proof  that  such  trees  would 
continue  to  grow  with  health  and  vigour. 

Any  information  which  the  gardener  might  derive  from  knowledge  of 
the  preceding  facts  would  be  of  very  little  value  if  every  part  of  seedling 
trees  were  in  the  same  degree  affected  by  age ;  but  it  is  not  so  ;  and  the 


ON    PROLONGING    THE    DURATION    OF    VARIETIES    OF    FRUITS.  325 

decay  of  the  powers  of  life  in  the  roots  of  seedling  trees  is  exceeding 
slow  comparatively  with  the  bearing  branches.  Scions,  obtained  from 
the  roots  of  pear-trees  of  two  hundred  years  old,  afford  grafts  which  grow 
with  great  vigour ;  and  which  in  many  cases  are  covered  with  thorns 
like  young  seedling  stocks,  whilst  other  grafts  taken  at  the  same  time 
from  the  extremities  of  the  branches  of  such  trees  present  a  totally 
different  character,  and  a  very  slow  and  unhealthy  growth.  I  do  not, 
however,  conceive  that  any  scion  which  thus  springs  from  the  root  of  an 
old  tree  possesses  all  the  powers  of  a  young  seedling  tree,  but  it  certainly 
possesses  no  inconsiderable  portion  of  such  powers ;  and  I  have  proved 
such  scions  to  be  capable  of  affording  healthy  trees  of  a  considerable  size. 

If  grafts  or  buds  were  taken  from  such  scions,  on  their  first  emission, 
much  time  would  elapse  before  any  blossom  would  be  produced :  but  if 
buds  were  not  taken  from  such  scions  till  the  branches  attained  the  age 
of  puberty,  no  loss  of  time  whatever  would  subsequently  occur. 

The  branches  of  the  plum-tree,  in  the  experiment  above-mentioned, 
emitted  roots  just  at  the  period  when  they  had  attained  the  age  of 
puberty ;  and  I  do  not  doubt,  but  that  scions  from  the  roots  of  these  will 
spring  from  the  soil  in  full  possession  of  all  the  powers  attached  to  the 
branches  from  which  they  derived  their  existence.  My  own  experience 
leads  me  to  think  that  trees  of  the  pear,  the  apple,  and  the  plum,  might 
be  better  raised  by  layers  and  cuttings  of  the  roots,  than  by  the  methods 
usually  practised,  and  at  less  expense. 

The  garden  of  the  Society  contains  many  varieties  of  fruits,  which  I 
believe  to  be  extremely  valuable  as  well  as  new ;  and  the  preservation  of 
these  permanently  in  their  pristine  and  present  state  of  health  and 
vigour,  appears  to  be  an  object  of  great  importance.  And  the  decay  of 
many  varieties  (such  as  the  Cornish  gilliflower-apple,  which  in  my 
estimation  is  and  always  was  without  a  rival  in  the  climate  of  England) 
might  be  greatly  retarded  by  propagating  it  from  scions  which  have 
recently  sprung  from  the  trunks  of  old  trees,  in  obedience  to  the  instruc- 
tions of  Virgil  (whose  authority  is  however  generally  of  little  value), 
and  probably  of  Hyginus,  "  summa  ne  pete  flagella." 


326 


LXXII.— UPON    GRAFTING   THE   WALNUT-TREE. 
\Read  before   the  HORTICULTURAL   SOCIETY,   April  llth,    1832.] 

THE  walnut-tree  appears  hitherto  to  have  effectually  baffled,  under  all 
ordinary  circumstances,  the  art  of  the  grafter.  The  inserted  scions 
wither  and  die,  without  apparently  making  any  effort  to  unite  them- 
selves to  the  stock,  or  to  draw  nutriment  from  it ;  and  consequently  the 
value  of  every  superior  variety  has  been  limited  by  its  use  to  the  possessor 
of  the  original  seedling-tree.  It  is  true  that  a  part  of  the  seedling 
offspring  of  every  fine  variety  generally  inherits  a  portion  of  its  good 
qualities  ;  but  I  have  found  it  extremely  difficult  to  obtain  from  seed 
good  varieties  of  sufficiently  early  habits  to  ripen  well  in  this  vicinity, 
except  in  very  warm  seasons ;  and  I  doubt  much  whether  the  value  of 
the  crop  of  walnuts,  throughout  the  British  Islands,  be  one-third  as 
great  as  it  would  be  if  proper  varieties  were  everywhere  planted. 

It  must,  however,  be  admitted,  that,  amongst  fruit-trees  in  general, 
ungrafted  seedling  plants  usually  afford  the  finest  trees  :  but  if  the  grafts 
be  taken  from  young  seedlings,  or  from  scions  which  have  sprung  out 
of  the  trunks,  or  large  branches,  of  trees  of  greater  age,  and  those  be 
varieties  of  luxuriant  and  healthy  growth,  the  vigour  and  durability  of 
the  future  tree  will  not  be  much  diminished.  The  more  early  production 
of  fruit,  by  grafted  trees,  will  necessarily,  to  some  extent,  impede  their 
growth ;  because  a  portion  of  their  sap  must  be  expended  in  giving 
nourishment  to  such  fruit :  but  the  largest  pear-trees  which  I  have  ever 
seen  must  have  sprung  from  grafts  taken  from  trees  of  considerable  age. 
One  of  these,  which  grows  upon  an  estate  that  belongs  to  me,  a  Barland 
pear-tree,  (an  old  variety  now  nearly  expended,)  has  been  known  to  afford, 
in  the  same  season,  two  hundred  and  seventy-five  gallons  of  perry. 

The  walnut-tree  may  be  propagated  with  more  success  by  budding. 
I  have  succeeded  tolerably  well  in  some  seasons,  and  in  one  season 
perfectly  well ;  but  in  several  others  not  a  single  inserted  bud  has  been 
found  alive  in  the  following  year,  though  all  had  been  inserted  with  the 
greatest  care. 

I  therefore  communicate  the  following  mode  of  grafting  the  walnut- 
tree,  which  I  found  in  the  last  season  most  perfectly  successful  under 
many  unfavourable  circumstances  ;  and  which  mode,  for  reasons  which  I 
shall  proceed  to  state,  will,  I  believe,  point  out  the  means  of  propagating 
some  other  species  of  trees  with  facility,  which  have  not  hitherto  been 
so  propagated  without  difficulty  and  uncertainty. 


UPON    GRAFTING    THE    WALNUT  TREE.  327 

The  fluid  which  the  seeds  of  the  walnut-tree  contain,  when  that  is 
fully  prepared  to  germinate  in  the  spring,  and  which  was  deposited 
within  it  for  the  purpose  of  affording  nutriment  to  the  seminal  buds,  or 
plumule,  in  the  preceding  autumn,  is  sweet,  as  in  a  great  many  other 
kinds  of  seeds  :  but  during  germination  this  becomes,  in  the  seed  of  the 
walnut-tree,  bitter  and  acrid.  Similar  changes  take  place  in  the  sap 
which  is  deposited,  for  analogous  purposes,  in  the  bark  and  wood  of  the 
walnut-tree,  during  the  germination  of  its  buds ;  and  I  was  led  by  the 
discoveries  of  M.  Dutrochet  to  infer  the  probability,  that  the  sap  during, 
and  subsequent  to,  its  chemical  changes,  might  acquire  new  and  more 
extensive  vital  powers.  I  therefore  resolved  to  suffer  the  buds  of  my 
grafts,  and  those  of  the  stocks,  to  which  I  proposed  to  apply  them,  to 
unfold,  and  to  grow  during  a  week  or  ten  days  ;  then  to  destroy  all  the 
young  shoots  and  foliage,  and  to  graft  at  a  subsequent  period.  A  very 
severe  frost  in  the  morning  of  the  7th  of  May  saved  me  the  trouble  of 
destroying  the  young  shoots  ;  but  it  deranged  my  experiment  by  killing 
much  of  the  slender  annual  wood,  which  I  proposed  to  use  for  grafts  ;  so 
that  I  found  some  difficulty  in  choosing  proper  grafts.  The  swelling  of 
the  small,  and  previously  almost  invisible,  buds,  within  a  few  days  enabled 
me  to  distinguish  the  living  wood  from  that  which  had  been  killed  by  the 
frost,  and  the  stocks  were  grafted  upon  the  18th  day  of  May.  My  grafter 
had  more  than  once  been  previously  employed  by  me  to  graft  walnut- 
trees  in  various  ways,  and  never  having  in  any  degree  succeeded,  he  did 
not  seem  at  all  pleased  with  the  task  assigned  him,  and  very  confidently 
foretold  that  every  graft  would  die  :  and  I  subsequently  found  that  he 
had  insured,  to  some  extent,  the  truth  of  his  prophesy,  by  having  applied 
grafts  which  were  actually  dead.  The  whole  number  employed  was 
twenty-eight,  and  out  of  these  twenty-two  grew  well ;  generally  very 
vigorously,  many  producing  shoots  of  nearly  a  yard  long,  and  of  very 
great  strength ;  and  the  length  of  the  longest  shoot  exceeding  a  yard  and 
five  inches.  The  grafts  were  attached  to  the  young  (annual)  wood  of 
stocks,  which  were  between  five  and  eight  feet  high ;  and  in  all  cases 
they  were  placed  to  stand  astride  the  stocks,  one  division  being  in  some 
instances  introduced  between  the  bark  and  the  wood  ;  and  both  divisions 
being,  in  others,  fitted  to  the  wood  or  bark  in  the  ordinary  way.  Both 
modes  of  operating  were  equally  successful.  In  each  of  these  methods  of 
grafting  it  is  advantageous  to  pare  away  almost  all  the  wood  of  both  the 
divisions  of  the  grafts ;  and  therefore  the  wide  dimensions  of  the  medulla 
in  the  young  shoots  of  the  walnut-tree  do  not  present  any  inconvenience  to 
the  grafter. 


328  UPON    GRAFTING    THE    WALNUT-TREE. 

No  difficulties  will  henceforth,  I  conclude,  occur  in  propagating  varieties 
of  walnuts  by  grafting;  and  I  am  much  inclined  to  believe,  that  different 
species  and  varieties  of  oaks  may  be  successfully  grafted  by  the  same 
mode  of  management. 

The  art  of  grafting  our  common  fruit  trees  has  been  so  long,  and  so 
extensively  practised,  that  it  may  reasonably  be  supposed  to  be,  at  this 
late  period,  incapable  of  much  improvement.  But,  nevertheless,  I  am 
much  inclined  to  believe  that  a  good  deal  is  still  to  be  learned  ;  and  it 
would  not  afford  matter  of  much  astonishment  to  me,  if  it  should  be 
proved  that  branches  provided  with  blossom-buds  might  be  transferred 
with  success  from  one  side  of  the  Atlantic  to  the  other,  to  afford  fruit  in 
the  following  season.  The  results  of  some  experiments,  which  I  made  in 
the  last  winter,  and  present  spring,  induce  me  to  think  this  practicable, 
though  I  am  not  yet  prepared  to  decide  that  it  is  so. 


LXXIII — ON    THE     BENEFICIAL    EFFECTS   OF    THE    ACCUMULATION    OF 

SAP   IN   ANNUAL   PLANTS. 

[Read  before  the  HOUTICULTURAL  SOCIETY,  December  2,Qth,  1830.] 

BIENNIAL  plants  very  obviously  form  in  one  season  the  sap,  which  they 
expend  in  the  following  season  in  the  production  of  blossoms  and  seeds  ; 
and  the  capacity  of  the  reservoirs  they  form  is  greater  or  less,  in  pro- 
portion as  external  circumstances  are  more  or  less  favourable.  Trees 
also  (as  I  conceive  myself  to  have  satisfactorily  proved  in  the  Philoso- 
phical Transactions)  generate  in  a  preceding  season,  or  seasons,  the  sap 
which  feeds,  in  the  spring,  their  unfolding  blossoms  and  young  leaves. 
Annual  plants,  on  the  contrary,  possess  no  such  reservoirs  ;  and  they 
must  generate,  in  each  season,  all  the  sap  which  they  can  expend,  exclu- 
sively of  the  very  small  portion  derived  from  the  seeds  from  which  they 
spring.  But  by  appropriate  management,  and  creation  of  varieties, 
annual  plants  may  be  made  to  accumulate,  in  one  period  of  their  lives, 
the  sap  which  they  expend  in  another,  with  very  great  advantages  to  the 
cultivator. 

The  first  produced  female  blossoms  of  the  melon-plant,  particularly  of 
the  larger  and  superior  varieties,  do  not  often  set ;  and  if  they  set,  the 
fruit  they  afford  never  attains  as  large  a  size,  or  as  much  excellence,  as 
the  same  plants,  at  a  more  mature  age,  would  have  given  to  it  under  the 
same  external  circumstances.  This,  I  imagine,  arises  not  only  from  the 


ON    THE    ACCUMULATION    OF    SAP    IN    ANNUAL    PLANTS.  329 

different  quantity,  but  from  the  different  qualities  of  the  sap  in  the 
young  and  in  the  more  mature  plant ;  for  I  have  found  the  sap  of  very 
young  birch  and  sycamore  trees  to  be  specifically  much  lighter,  and  to 
contain  much  less  saccharine  matter,  than  the  sap  of  trees  of  greater  age 
of  the  same  species,  and  growing  in  the  same  soil,  and  in  the  same 
seasons.  Under  the  influence  of  abundant  light,  in  those  climates  in 
which  the  melon  was  placed  by  nature,  the  first  formed  fruit  probably 
acquires  a  high  state  of  perfection,  possibly  greater  than  it  can  ever  be 
made  to  acquire  in  less  favourable  climates.  But  this  I  am  much  dis- 
posed to  question,  and  to  believe  that,  by  proper  management,  the  melon 
may  be  made  to  acquire  in  the  climate  of  England  a  degree  of  excellence 
which  it  is  very  rarely  found  to  possess  in  any  climate,  and  that  the 
degeneracy  of  the  finest  varieties  may  be  totally  prevented. 

Very  young  plants  of  the  sweet  melon  of  Ispahan  (the  variety  which 
till  within  the  present  year  I  have  chiefly  cultivated)  very  rarely  show 
fruit ;  and  in  my  melon-house  I  never  suffer  a  lateral  shoot  or  blossom 
of  this  variety  to  be  produced  at  a  less  distance  from  the  root  than  that 
of  the  fourteenth  or  fifteenth  joint  above  the  seed-leaves :  and  when  I  am 
anxious  to  obtain  the  fruit  and  seeds  in  the  highest  state  of  perfection, 
I  do  not  suffer  a  blossom  to  be  produced  nearer  the  root  than  its 
eighteenth  or  twentieth  joint.  Under  this  mode  of  management,  the 
expenditure  of  sap,  being  confined  to  the  extremity  of  a  single  stem,  is 
very  small  comparatively  with  the  creation  of  it ;  and  it  consequently 
accumulates,  and  the  fruit  is  therefore  most  abundantly  nourished, — I 
conceive  more  abundantly  than  it  usually  is  in  any  natural  climate  :  and 
its  growth  is  always  enormously  rapid. 

The  striped  and  green  Hoosainee  melon-plants,  of  which  I  received 
seeds  from  the  Horticultural  Society  in  the  last  spring,  being  much 
disposed  to  bear  fruit,  produced  blossoms  at  their  third  joints ;  but 
being  desirous  of  obtaining  the  fruit  and  seeds  of  those  varieties  in  the 
highest  possible  state  of  perfection,  I  subjected  those  varieties  to  the 
same  mode  of  management,  and  I  believe  with  the  best  success,  though 
I  am  ignorant  of  the  merits  of  those  varieties  under  other  circumstances. 

The  fruit  of  the  striped  Hoosainee  melon-plant  requires  a  very  long 
period  to  attain  maturity  after  it  has  attained  its  full  growth,  and  after 
it  has  apparently  ceased  to  draw  much  nourishment  from  the  plant. 
During  this  period,  I  conceived  that  the  plants,  having  all  their  foliage 
in  a  perfectly  healthy  state,  must  be  in  the  act  of  generating  much  more 
sap  than  they  were  expending,  and  I  therefore  suffered  two  plants,  from 
which  I  took  off  the  fruit  in  the  end  of  August,  to  remain  wholly 


S30  ON    THE    ACCUMULATION    OP    SAP    IN    ANNUAL    PLANTS. 

unpruned.  Much  fruit  was  in  consequence  soon  offered,  and  I  obtained 
very  good  melons  for  any  season,  and  perfectly  well  grown,  in  the  latter 
end  of  the  last  month  (November),  which  fruit,  I  do  not  entertain  any 
doubt,  was  chiefly  nourished  by  sap  generated  in  the  month  of  August. 

The  quality  of  some  Ispahan  melons,  which  I  have  sent  to  the  Society, 
has  afforded,  I  believe,  satisfactory  evidence  that  that  variety  has  not 
become  deteriorated  by  having  been  raised  through  many  successive 
generations  in  the  unfavourable  climate  of  this  place :  but  the  following 
statement,  I  think,  affords  strong  evidence  that,  like  other  highly  im- 
proved varieties,  it  does  degenerate  under  our  ordinary  modes  of  culture. 
Sir  Harford  Jones  Brydges,  from  whom  I,  many  years  ago,  first  received 
seeds  of  this  variety,  informed  me,  in  the  beginning  of  the  last  year,  that 
it  had  so  much  degenerated  and  diminished  in  size,  that  he  had  ceased 
to  cultivate  it.  He  then  received  a  few  seeds  from  me,  from  which  he 
assured  me,  in  the  last  month,  that  he  had  obtained  melons  in  the  present 
year,  scarcely  inferior  to  any  he  had  eaten  in  Persia; — conclusive  evidence, 
I  think,  that  the  finest  Persian  varieties  of  the  melon  do  not  necessarily 
degenerate  in  the  climate  of  England. 

Every  gardener  who  has  been  in  the  habit  of  raising  cucumbers  in 
winter  perfectly  well  knows  the  advantages  of  raising  his  plants  in  July 
or  August,  and  preventing  their  expending  themselves  in  the  production 
of  blossoms  or  fruit  till  they  have  been  introduced  into  the  stove.  The 
general  opinion  of  gardeners  is,  that  such  plants  succeed  best  only  because 
their  stems  are  more  firm  and  ligneous  than  those  of  young  plants ;  but 
I  feel  confident  that  the  real  cause  of  their  succeeding  best  is  the 
existence  of  accumulated  sap  within  them.  I  have  a  melon-plant  now 
growing  in  the  stove,  which  sprang  from  a  seed  sown  in  the  end  of  July, 
but  upon  which  no  fruit  was  made  to  set  till  the  1st  day  of  November. 
The  plant  possesses  abundant  foliage,  and  the  fruit  has  grown  tolerably 
well,  and  it  will,  I  conclude,  be  ripe  about  Christmas.  Upon  the  23d  of 
October  I  placed  a  blossom,  which  had  been  produced  by  a  Dampsha 
melon-plant,  from  which  I  had  a  few  days  before  taken  the  fruit,  within 
the  distance  of  an  inch  of  a  very  warm  flue,  where  the  temperature  of 
the  air  was  never  below  86°.  In  this  situation  the  fruit  set  well,  and 
grew  with  most  extraordinary  rapidity,  though  it  was  so  near  the  front 
wall,  and  so  far  (nearly  three  feet)  from  the  glass,  that  no  direct  ray  of 
the  sun  could  fall  upon  it.  At  the  end  of  seven  days  precisely  from  the 
period  when  the  pollen  was  put  into  the  flower,  I  measured  the  fruit, 
when  it  was  seven  inches  long,  and  seven  inches  and  a  half  in  circum- 
ference. On  the  10th  day  the  fruit  suddenly  ceased  to  grow,  having 


ON    THE    ACCUMULATION    OF    SAP    IN    ANNUAL    PLANTS.  331 

apparently  exhausted  the  reservoir  whence  it  drew  nutriment,  and  the 
plant  withered ;  on  the  fourteenth  day  the  fruit  was  gathered,  when  it 
weighed  very  nearly  a  pound  and  a  half.  If  the  days  had  been  long,  and 
the  weather  bright,  the  creation  of  sap  would,  I  conclude,  have  nearly 
kept  pace  with  the  very  rapid  expenditure  of  it ;  and  the  plant  would 
not  have  died,  as  it  apparently  did,  of  exhaustion. 

By  delaying  the  period  of  sowing  the  seeds  of  many  species  of  plants 
(the  turnip  and  some  varieties  of  the  cabbage  afford  examples),  those 
which  would  have  afforded  flowers  and  seeds  within  the  same  season 
form  reservoirs  of  accumulated  sap  in  autumn,  which  becomes,  during 
winter,  the  food  of  man  and  other  animals. 

Proportionably  late  varieties  of  different  species  of  annual  plants  gene- 
rate, in  one  part  of  their  lives,  the  sap  which  they  expend  in  another.  I, 
every  season,  plant  in  the  beginning  of  June,  and  a  little  earlier,  a  large 
quantity  of  the  very  late  variety  of  pea  which  bears  my  name ;  and  by 
supplying  the  plants  abundantly  with  water  I  prevent  (as  I  have  stated 
in  a  communication  to  the  Society  many  years  ago),  to  a  very  great 
extent,  the  injurious  effects  of  mildew :  and  by  these  means  I  regularly 
obtain  a  most  abundant  supply  of  peas  in  September  and  October,  and 
of  better  quality  than  I  can  obtain  in  the  month  of  June.  In  this  case 
the  sap  which  is  prepared  in  the  summer  is  obviously  expended  in  the 
autumn. 

The  good  effects  which  I  have  proved  to  arise  from  planting  large 
tubers  of  the  potatoe-plant  obviously  spring  from  the  large  accumulation 
of  sap  in  them.  Fed  by  means  of  this,  not  only  a  large  breadth  of 
foliage  is  produced  and  exposed  to  sight  more  early  in  the  year  ;  but  that 
foliage  contains  much  disposable  organisable  matter,  which  once  formed 
a  part  of  the  parent  tuber.  Any  person  who  will  pay  close  attention  to 
the  growth  of  produce  of  early  crops  of  potatoes,  which  have  sprung 
from  large  tubers,  will  readily  obtain  ample  evidence  of  the  truth  of  this 
position.  The  variation  in  the  comparative  growth  of  fruits  of  different 
species  in  similar  seasons  frequently  arises,  I  have  good  reason  to  believe, 
from  the  more  or  less  perfect  state  of  the  reservoir  formed  in  the 
preceding  year ;  and  every  experienced  gardener  knows  that  under  any 
given  external  circumstances,  the  blossom  of  his  fruit  trees  sets  best 
when  the  preceding  season  has  been  warm  and  bright,  and  when  his 
trees,  in  such  season,  have  not  expended  their  sap  in  supporting  heavy 
crops  of  fruit. 

Note  by  the  Secretary — The  quality  of  the  Ispahan  melons  referred  to  in  the  preceding 
paper  was  found,  when  the  fruit  was  tasted  at  the  house  of  the  Society,  to  be  of  the  highest 
excellence  which  it  is  supposed  that  the  melon  is  capable  of  attaining  in  this  country. 


332 


LXX1V.— ON  THE  ADVANTAGES  OF  IRRIGATING  GARDEN  GROUNDS 
BY  MEANS  OF  TANKS  OR  PONDS. 

[Read  before  the  HORTICULTURAL  SOCIETY,  August  1th,  1832.] 

THE  quantity  of  water  which  may  be  given  with  advantage  to  plants  of 
almost  every  kind,  during  warm  and  bright  weather,  is,  I  believe,  very 
much  greater  than  any  gardener,  who  has  not  seen  the  result,  will  be 
inclined  to  suppose  possible ;  and  it  is  greater  than  I  myself  could  have 
believed  upon  any  other  evidence  than  that  of  actual  experience. 

My  garden,  in  common  with  many  others,  is  supplied  with  water  by 
springs,  which  rise  in  a  more  elevated  situation  ;  and  this  circumstance 
afforded  me  the  means  of  making  a  small  pond,  from  which  I  can  cause 
the  water  to  flow  out  over  every  part  of  my  garden  whenever  I  wish.  I 
am  thus  enabled  to  irrigate  my  strawberry  beds  whilst  in  flower,  and  my 
alpine  strawberry  beds,  and  plants  of  every  other  kind,  through  every 
part  of  the  summer ;  and  I  cause  a  stream  to  flow  down  the  rows  of  celery 
and  along  the  rows  of  brocoli,  and  other  plants  which  are  planted  out  in 
summer,  with  very  great  advantage.  But  the  most  extensive  and  bene- 
ficial use  which  I  make  of  the  power  to  irrigate  my  garden  by  the  means 
above  mentioned  is  in  supplying  my  late  crops  of  peas  abundantly  with 
water  ;  by  which  the  ill  effects  of  mildew  are  almost  wholly  prevented, 
and  my  table  is  most  abundantly  supplied  with  very  excellent  peas  through 
the  month  of  October,  as  I  have  stated  in  a  former  communication. 
Several  of  my  friends,  who  have  caused  large  quantities  of  water  to  be 
carried,  have  obtained  abundant  crops  late  in  the  autumn  of  the  variety 
of  pea  which  bears  my  name ;  but  they  have  complained  that  the 
birds  have  eaten  the  whole  crop.  This  will  almost  always  occur  where 
means  are  not  taken  to  prevent  it :  but  there  are  only  two  species 
of  bird  which  ever  break  open  the  pods  of  green  peas,  the  large  black- 
headed  and  the  blue /tit  mouse  (the  Parus  major  and  Parus  cseruleus  of 
Linnaeus),  and  both  these  are  very  easily  caught.  The  coal  titmouse,  the 
nuthatch,  the  chaffinch,  and  the  robin,  will  eat  the  peas  when  the  pods 
are  opened  ;  but  neither  of  these  ever  break  them.  For  the  purpose  of 
taking  such  birds,  I  employ  a  little  trap,  which  I  invented  when  a  school- 
boy, and  which  secures  without  injuring  them,  and  enables  me  to  release 
the  unoffending ;  and  I  do  not  find  the  smallest  difficulty  in  preserving 
my  crops  of  peas  in  any  season. 

When  water  is  delivered  in  the  usual  quantity  from  the  watering- pan, 
its  effects,  for  a  short  time,  are  almost  always  beneficial,  by  wetting  the 


ON    THE    ADVANTAGES    OF    IRRIGATING    GARDEN    GROUNDS.  333 

surface  of  the  ground.  But  if  water  thus  given  be  not  continued 
regularly,  injurious  effects  frequently  follow ;  for  the  roots  of  plants  (as 
I  have  shown  in  the  Philosophical  Transactions,  in  a  paper  upon  the 
causes  which  direct  the  roots  *)  extend  themselves  most  rapidly  wherever 
they  find  proper  moisture  and  food ;  and  if  the  surface  alone  be  wetted, 
the  roots  extend  themselves  superficially  only,  and  the  plants  consequently 
become  more  subject  to  injury  from  drought  than  they  would  have  been 
if  no  water  had  been  given  to  them  ;  a  circumstance  which  can  scarcely 
have  escaped  the  notice  of  any  observant  gardener.  When,  on  the  con- 
trary, the  soil  is  irrigated  in  the  manner  above  recommended,  it  is 
wetted  to  a  great  depth ;  and  a  single  watering  once  in  eight  or  ten 
days  is,  in  almost  all  cases,  fully  sufficient. 

I  have  found  the  advantage  of  being  able  to  command,  by  the  means 
above-mentioned,  abundant  water  at  all  seasons,  and  at  very  small  expense, 
so  great,  that  I  feel  confident  that  a  market  gardener  could,  in  many 
cases,  afford  to  give  as  much  rent  for  one  acre  as  he  could  under  ordinary 
circumstances  give  for  two  acres  ;  for  he  would  not  only  be  able  generally 
to  command  more  abundant  crops,  but,  by  possessing  exclusive  advantages, 
he  would  often,  in  unfavourable  seasons,  be  enabled  to  raise  abundant 
crops  of  articles  which,  in  such  seasons,  usually  take  a  very  high  price. 
In  selecting  the  site  of  a  garden  the  advantage  of  irrigating  it,  by  the 
means  above-mentioned,  may  very  frequently  be  obtained  ;  and  the  num- 
ber of  gardens  above  which  a  small  tank  or  pond  might  be  easily  made 
is  probably  much  greater  than  at  a  first  view  will  be  supposed. 

It  may  be  objected  that  excess  of  rain  is  more  often  injurious  in  the 
climate  of  England  than  drought ;  but  in  wet  seasons  plants  suffer  owing 
to  want  of  light,  and  generally  of  warmth ;  and  I  feel  confident  that  if 
the  same  quantity  of  rain,  which  the  soil  receives  in  our  wettest  summer, 
were  to  fall  only  between  the  hours  of  nine  in  the  evening  and  three  in 
the  following  morning,  and  the  sun  were  to  shine  brightly  and  warmly 
through  the  whole  of  the  days,  no  injurious  effects  would  follow ;  and 
every  experienced  gardener  knows  with  what  luxuriance  and  rapidity 
plants  of  every  species  grow  in  hot  and  bright  weather,  after  the  ground 
has  been  drenched  with  water  by  thunder-storms. 

*  See  above,  p.  157. 


334 


LXXV.— ON    THE    CULTURE    OF  THE    POTATOE. 

[Read  before  the    HORTICULTURAL    SOCIETY,    March    19 th,    1833.] 

I  HAVE  so  often  addressed  communications  to  this  Society  upon  the 
culture  of  the  potatoe,  that  many  of  its  members  may  hot  improbably 
think  that  more  than  a  sufficient  extent  of  the  pages  of  our  Transactions 
have  been  already  devoted  to  that  subject.  It  would  certainly  not  be 
difficult  to  find  one  more  entertaining ;  but  if  the  farmer  can  be  made  to 
derive  such  information  from  our  Transactions  as  will  enable  him  to  cause 
the  same  space  of  ground  which  now  affords  one  bushel  of  potatoes  to 
afford  two,  and  the  peasant  to  cause  the  half  acre  which  now  supplies 
his  table  with  potatoes  to  afford  him  in  addition  a  considerable  weight  of 
animal  food,  few  subjects  can  be  more  important ;  and  therefore,  con- 
ceiving myself  to  be  prepared  to  communicate  some  further  useful  infor- 
mation, I  venture  to  address  another  communication  upon  the  same 
subject. 

The  fact  that  every  variety  of  potatoe  when  it  has  been  long  propagated 
from  parts  of  its  tuberous  roots  becomes  less  productive,  is,  I  believe, 
unquestionable.  1  have  often  witnessed  the  progressive  decay  of  vigour, 
and  the  different  effects  of  the  influence  of  age,  upon  many  different 
varieties.  The  quality  of  some  has  remained  perfectly  good,  after  the 
produce  in  quantity  has  become  highly  defective ;  whilst  in  others  that 
has  disappeared  with  the  vigour  of  the  plant.  I  brought  to  this  place  a 
single  tuber  of  Lankman's  potatoe  soon  after  that  was  imported :  the 
produce  of  that  variety  was  then,  and  continued  during  some  successive 
years,  very  great ;  but  its  vigour  was  gradually  diminished ;  and  in  the  last 
year  its  produce  was  at  least  one  third  (more  than  seven  tons  per  acre) 
less  than  I  obtained  from  the  same  soil,  and  under  in  every  respect  the 
same  management,  from  other  varieties  of  nearly  similar  habits,  but 
which  had  recently  sprung  from  seed.  The  propagation  of  expended 
varieties,  therefore,  appears  to  me  to  be  one  of  the  causes  why  the 
crops  of  potatoes  generally  have  been  found  so  much  less  than  those 
which  I  have  stated  to  have  been  produced  here.  I  have  received  letters 
within  a  few  months  from  persons  in  different  parts  of  the  kingdom, 
informing  me  that  they  have  been  unable  to  obtain  by  any  mode  of 
culture  above  two  hundred  and  fifty  or  three  hundred  bushels  of  potatoes 
from  an  acre  of  good  and  well-manured  ground.  I  have  in  answer  desired 
to  know  the  age  of  the  varieties  cultivated ;  but  upon  that  point  I  have 
uniformly  found  my  correspondents  totally  uninformed ;  communicating 


ON  THE  CULTURE  OF  THE  POTATOE.  335 

to  me,  however,  the  important  intelligence  that  the  same  varieties  bore 
more  abundantly  at  a  former  period,  and  often  that  the  quality  of  the 
former  produce  was  superior.  When  I  first  stated,  in  a  former  commu- 
nication, that  I  had  obtained  a  produce  equivalent  to  six  hundred  and 
seventy  bushels  of  eighty  pounds  per  acre,  I  found  some  difficulty  in 
obtaining  credit  for  the  accuracy  of  my  statement,  though  T  then  felt 
perfectly  confident  that  by  first  obtaining  varieties  better  adapted  to  my 
purpose,  I  should  be  able  to  raise  much  heavier  crops ;  and  the  following 
statement,  in  support  of  which  I  am  prepared  to  adduce  the  most 
unquestionable  evidence,  will  prove  that  my  confidence  was  perfectly  well 
founded. 

I  planted  in  my  garden,  in  the  last  season,  some  tubers  of  a  variety  of 
potatoe  of  very  early  habits,  but  possessing  more  vigour  of  growth  than  is 
usually  seen  in  such  varieties.  The  soil  in  which  they  were  planted  was  in 
good  condition,  but  not  richer  than  the  soils  of  gardens  usually  are,  and 
the  manure  which  it  had  received  consisted  chiefly  of  decayed  oak  leaves, 
which  I  prefer  to  other  manures,  because  it  never  communicates  a  strong 
taste  or  flavour  to  any  vegetable.  No  previous  preparation  was  given  to 
the  soil,  and  the  spot  where  the  plantation  was  made  was  not  fixed  upon 
till  the  day  of  planting ;  and  no  manure  of  any  kind  was  then  given. 
Owing  to  the  variety  being  of  a  very  excitable  habit,  I  planted  the  tubers 
at  least  nine  inches  deep  in  the  soil,  and  I  subsequently  raised  the  mould 
in  ridges  three  inches  high  to  prevent  the  young  plants  sustaining 
injury  from  frost ;  but  no  subsequent  moulding  was  given.  I  antici- 
pated from  the  previous  produce  of  the  variety,  which  I  had  raised  by 
cross-breeding  from  two  early  varieties  in  1830,  a  very  extraordinary 
crop ;  and  I  therefore  invited  several  gardeners  and  farmers  to  witness 
the  amount  of  it;  and  I  procured  the  attendance  of  the  two  most  eminent 
agriculturists  of  the  vicinity,  who  were  tenants  to  other  gentlemen.  The 
external  rows  (two  deep),  and  the  external  plants  at  the  ends  of  all  the 
remaining  rows,  were  taken  away,  and  the  produce  of  the  interior  part 
of  the  plantation  was  alone  selected ;  and  that  was  pronounced  to  be  fully 
equivalent  to  nine  hundred  and  sixty-four  bushels  and  forty-three  pounds, 
or  34  tons  8  cwt.  107  Ibs.  per  statute  acre.  Still  larger  crops  may,  I 
feel  satisfied,  be  obtained,  and  my  opinion  is,  that  more  than  a  thousand 
bushels  of  potatoes  may,  and  will  be,  obtained  from  an  acre  of  ground. 

An  opinion  is  I  believe  generally  prevalent,  that  varieties  of  potatoes 
of  very  high  and  luxuriant  growth  are  capable  of  affording  per  acre  the 
greatest  weight  of  produce :  but  this  is  certainly  erroneous.  Such  will 
grow  in  poorer  soil,  and,  requiring  wider  intervals  between  the  rows,  are 


336  ON  THE  CULTURE  OF  THE  POTATOE. 

better  calculated  for  culture  with  the  plough ;  and  therefore,  perhaps, 
their  produce  may  be  raised  at  as  little  or  less  cost  per  bushel,  though 
that  is,  I  think,  very  questionable.  Much  time  and  much  labour  of  the 
plant  must  be  expended  in  raising  the  nutriment  absorbed  from  the  soil 
into  the  leaves  upon  the  top  of  a  very  tall  stem,  and  down  again  to  the 
roots  and  tubers. 

The  potatoes,  in  the  extraordinary  crop  of  which  I  have  above  spoken, 
were  not  washed,  and  therefore  a  deduction  must  be  made  for  a  portion 
of  soil  which  adhered  to  them :  but  that  was  small,  owing  to  the  dryness 
and  nature  of  the  soil.  Supposing  a  deduction  of  one  hundred  and  sixty- 
four  bushels  be  made  in  the  above-mentioned  account,  and  to  afford 
potatoes  sufficient  to  plant  the  acre  of  ground  again,  eight  hundred 
bushels  would  still  remain ;  and  these,  if  judiciously  given  to  proper 
animals,  would  certainly  give  twelve  hundred  pounds  of  animal  food. 

For  this  purpose  early  varieties  of  potatoes  possess  great  advantages ; 
because  all  our  domesticated  animals  thrive  most  on  potatoes  after  these 
have  begun  to  germinate  :  and  if  those  of  early,  and  of  course  of  very 
excitable  habits,  be  taken  up  and  collected  into  heaps,  as  soon  as  they 
have  acquired  maturity,  they  will  germinate  in  autumn,  and  be  fit  for 
use,  without  being  boiled,  through  the  winter.  Potatoes  of  such  varieties 
are,  however,  wholly  unfit  for  human  food  late  in  the  spring ;  and  for 
such  purpose  those  of  later  and  less  excitable  habits  must  be  cultivated. 
Of  such  kinds  in  the  last  season,  which  was  not  favourable,  owing  to  the 
plants  having  suffered  injury  from  drought,  I  obtained  a  produce  varying 
from  twenty  to  twenty-four  tons  per  acre,  the  soil  being  naturally  light 
and  poor,  and  not  more  highly  manured  than  would  have  been  necessary 
for  a  crop  of  Swedish  turnips. 


LXXVI.— UPON  THE  CAUSES  OF  THE  PREMATURE  DEATH  OF  PARTS 
OF  THE  BRANCHES  OF  THE  MOOR-PARK  APRICOT,  AND  SOME  OTHER 
WALL  FRUIT-TREES. 

[Read  before  the  HORTICULTURAL  SOCIETY,  June  2nd,  1835.] 

THE  branches  of  all  trees,  during  much  the  larger  portion  of  the 
periods  in  which  they  continue  to  live,  are  in  their  natural  situations 
kept  in  continual  motion,  by  the  action  of  wind  upon  them;  and  of 
this  motion  their  stems  and  superficial  roots  partake,  whenever  the 
gales  of  wind  are  even  moderately  strong:  and  I  have  shown,  in  the 


THE    PREMATURE    DEATH    OF    THE    BRANCHES    OF    WALL    FRUIT-TREES.     337 

Philosophical  Transactions,  that  the  forms  of  all  large  and  old  trees 
must  have  been  much  modified  by  this  agent.  The  motions  of  the 
circulating  fluids,  and  sap  of  the  tree,  are  also  greatly  influenced  and 
governed  by  it ;  and  whenever  any  part  of  the  root,  the  stem,  or  the 
branches  of  a  tree  are  bent  by  winds  or  other  agents,  an  additional 
quantity  of  alburnum  is  there  deposited  ;  and  the  form  of  the  tree 
becomes  necessarily  well  adapted  to  its  situation,  whether  that  be 
exposed  or  sheltered.  If  exposed  to  frequent  and  strong  agitation, 
its  stem  and  branches  will  be  short  and  rigid,  and  its  superficial  roots 
will  be  large  and  strong ;  and  if  sheltered,  its  growth  will  be  in  every 
part  more  feeble  and  slender.  I  have  much  reason  to  believe,  upon 
the  evidence  of  subsequent  experiments,  that  the  widely-extended 
branches  of  large  timber- trees  would  be  wholly  incapable  of  supporting 
their  foliage  when  wetted  with  rain,  if  the  proportions  of  their  parts 
were  not  to  be  extensively  changed  and  their  strength  greatly  aug- 
mented by  the  operation  of  winds  upon  them  during  their  previous 
growth.  Exercise,  therefore,  appears  to  be  productive  of  somewhat 
analogous  effects  upon  vegetable  and  upon  animal  life,  and  to  be  nearly 
as  essential  to  the  growth  of  large  trees  as  to  that  of  animals. 

Whenever  the  branches  of  a  tree  are  bound  to  a  wall,  they  wholly  lose 
the  kind  of  exercise  above  described,  which  nature  obviously  intended 
them  to  receive ;  and  many  ill  consequences  generally  follow — not,  how- 
ever, to  the  same  extent,  nor  precisely  of  the  same  kind,  to  trees  of 
different  species  and  habits.  When  a  standard  plum  or  peach  tree  is 
permitted  to  take  its  natural  form  of  growth,  its  sap  flows  freely 
and  most  abundantly  to  the  extremities  of  its  branches,  and  it  con- 
tinues to  flow  freely  through  the  same  branches  during  the  whole  life 
of  the  tree  :  but  when  the  branches  are  bound  to  a  wall,  and  are  no 
longer  agitated  by  winds,  each  branch  becomes  in  a  few  years  what 
Duhamel  calls  ;"  usee,"  that  is,  debilitated  and  sapless,  owing  apparently 
to  its  being  no  longer  properly  pervious  to  the  ascending  sap,  This 
obstruction  to  its  ascent  causes  luxuriant  shoots  to  spring  from  the  lower 
parts  of  the  tree  ;  and  these  are  in  succession  made  to  occupy  the  places 
of  the  debilitated  older  branches  by  the  process  which  the  gardener 
calls  "cutting  in." 

The  branches  of  the  apricot,  and  particularly  of  the  Moor-park 
varieties,  often  die  suddenly,  owing  to  the  same  cause,  with  much  more 
inconvenience  and  loss  very  frequently  to  the  gardener ;  for  trees  of  this 
species  do  not  usually  afford  him  the  means  of  filling  up  vacancies  upon 
his  wall,  as  those  of  the  peach  and  plum  do. 


338     THE    PREMATURE    DEATH    OF    THE    BRANCHES    OF    WALL    FRUIT-TREES. 

The  pear-tree  better  retains  its  health  and  vigour,  when  trained  to  a 
wall,  than  those  of  either  of  the  preceding  species,  or  than  the  cherry- 
tree  ;  but  the  proper  course  of  its  sap  is  nevertheless  greatly  deranged  ; 
and  it  is  difficult,  and  in  some  varieties  almost  impossible,  to  cause  it 
to  flow  properly  to  the  extremities  or  nearly  to  the  extremities  of  its 
branches.  Much  the  larger  part  of  it  is  generally  expended  in  the 
production  of  what  are  called  "foreright"  useless  shoots;  and  the 
quantity  of  fruit  which  is  afforded  by  the  central  parts  of  an  old  pear- 
tree,  when  trained  to  a  wall,  is  usually  very  small. 

The  vine  alone  amongst  fruit-trees  appears  capable  of  being  bound 
and  trained  to  a  great  distance  upon  a  wall  without  sustaining  any 
injury,  its  sap  continuing  to  flow  freely  and  abundantly  to  its  very  distant 
branches.  Owing  to  a  peculiarity  of  structure  and  habit  which  is  con- 
fined to  those  species  of  trees  from  which  nature  has  withheld  the  power 
of  supporting  their  own  branches,  the  alburnum  of  all  plants  of  this 
habit  is  (as  far  as  I  have  had  opportunities  of  observing)  excessively 
light  or  porous  ;  and  not  being  intended  by  nature  to  support  its  own 
weight,  or  that  of  any  part  of  the  foliage  of  the  tree,  does  not  acquire 
with  age  any  increased  solidity,  like  that  of  trees  of  a  different  habit ;  and 
on  this  account  probably  it  never,  how  long  soever  deprived  of  exercise, 
loses  in  any  degree  its  power  of  transmitting  the  ascending  sap.  The 
alburnum  of  those  trees  which  nature  has  caused  to  support  themselves 
without  external  aid,  becomes  annually  more  firm  and  solid,  and  con- 
sequently less  well  adapted  to  afford  a  passage  to  the  ascending  sap,  and 
as  heart- wood  it  is  totally  impervious  to  that  fluid.  Whenever  the 
branches  of  such  trees  are  wholly  deprived  of  exercise,  too  rapid  an 
increase  of  the  solidity  of  the  alburnum  probably  takes  place  ;  and  it  in 
consequence  ceases  to  be  capable  of  properly  executing  its  office.  I  have, 
of  course,  never  had  an  opportunity  of  examining  the  character  of  the 
alburnum"  of  the  Glycine  sinensis,  of  which  the  garden  of  this  Society 
contains  so  splendid  a  tree  ;  but  I  do  not  entertain  a  shadow  of  a  doubt 
of  its  being  extremely  light  and  porous,  like  that  of  other  trailing  and 
creeping  plants  which  depend  for  support  upon  other  bodies. 


339 


LXXVIL— ON   THE    MEANS    EMPLOYED    IN    RAISING    A   TREE    OF  THE 
IMPERATRICE   NECTARINE. 

[Read  before  the  HORTICULTURAL  SOCIETY,  February  3rd,  1835.] 

I  WAS  informed  in  the  last  spring  that  the  Society's  garden  did  not 
contain  a  tree  of  the  Imperatrice  nectarine,  and  that  it  was  wished  to 
obtain  one.  I  in  consequence  promised  that  I  would  raise  and  send  one 
as  soon  as  I  could ;  and  I  believe  that  the  means  which  I  employed  in 
raising  a  tree  of  that  variety  will  prove  that  I  have  not  lost  time  in 
proceeding  to  perform  my  promise. 

The  tree  which  I  send  is  composed  of  an  almond- stock  which  sprang 
from  seed  early  in  the  last  spring,  into  which  two  buds  were  inserted  on 
opposite  sides  in  the  end  of  April ;  and  as  soon  as  those  had  properly 
united  themselves  to  the  stock,  that  was  removed  from  the  forcing-house, 
and  placed  under  a  north  wall.  After  a  few  days  it  was  headed  dowrn, 
and  brought  again  into  the  forcing-house,  when  the  two  inserted  buds 
vegetated,  and  each  produced  a  lateral  branch,  which  has  acquired  the 
length  of  about  two  feet  six  inches,  and  has  formed  a  few  blossom-buds. 
I  had  previously,  early  in  the  spring,  grafted  an  almond-stock  which  was 
a  year  old  with  the  Imperatrice  nectarine,  with  the  intention  of  obtaining 
a  tree  to  send  to  you  ;  but  it  acquired,  early  in  the  summer,  too  large  a 
size  ;  and  it  was  consequently  planted  out  to  fill  up  a  vacancy  upon  my 
south  wall,  where  it  has  produced  two  branches,  each  of  which  is  more 
than  six  feet  long ;  and  it  has  covered  fifty  square  feet  of  the  wall  with 
much  excellent  bearing-wood.  I  have  never  witnessed  such  rapidity 
and  excellence  of  growth  in  a  peach  or  nectarine  tree,  planted  at  the 
usual  periods. 

The  almond  as  a  stock  for  the  peach  and  nectarine  possesses,  I  think, 
every  good  quality,  except  that  of  bearing  transplantation  very  well,  and 
in  that  respect  alone  it  is  inferior  to  the  plum-stock.  I  have,  on  this 
account,  sent  the  little  plant  above  mentioned  in  the  pot  in  which  the 
almond  was  first  planted. 

In  the  soil  and  climate  of  this  place  the  Imperatrice  nectarine  is,  in 
my  estimation  and  in  that  of  a  great  many  other  persons  who  have  tasted 
it,  the  best  fruit  of  its  family.  It  presents,  I  think,  a  greater  concen- 
tration of  taste  and  flavour  than  is  found  in  any  other  variety  which  I 
have  cultivated.  It  is  inferior  in  size  to  the  Dovvnton  nectarine :  but 
that,  in  favourable  seasons,  is  here  very  large  ;  one  measured  in  circum- 
ference nine  inches,  and  several  of  them  exceeded  eight  inches  and  seven 


340  ON    RAISING    A    TREE    OF    IMPERATRICE    NECTARINE. 

lines.  I  named  it  the  Imperatrice  nectarine,  because  the  first  fruits 
which  I  saw  shrivelled  much  upon  the  tree ;  but  those  have  not 
subsequently  done  so  more  than  some  other  varieties  of  nectarines. 

I  will  request  that  the  little  tree  sent  may  be  planted  in  fresh 
unmannred  soil  without  having  the  branches  shortened,  and  so  super- 
ficially that  a  part  of  its  roots  may  remain  permanently  visible  above  the 
soil.  The  fruit  which  it  will  produce  will  not  be  nearly  as  good  as  that 
of  an  older  tree ;  and  it  is  therefore  my  wish  that  some  buds  should  be 
taken  from  it  in  the  next  season,  and  inserted  into  the  branches  of  more 
mature  trees. 


LXXVIII.— ON   THE    PROPAGATION    OF  TREES  BY  CUTTINGS  IN    SUMMER. 

[Head  before  the  HORTICULTURAL  SOCIETY,  April  3rd,  1838.] 

WHEN  a  cutting  of  any  deciduous  tree  is  planted  in  autumn,  or  winter, 
or  spring,  it  contains  within  it  a  portion  of  the  true,  as  it  has  been  called, 
or  vital  sap,  of  the  tree  of  which  it  once  formed  a  part.  This  fluid,  rela- 
tively to  plants,  is  very  closely  analogous  to  the  arterial  blood  of  animals  ; 
and  I  shall  therefore,  to  distinguish  it  from  the  watery  fluid,  which  rises 
abundantly  through  the  alburnum,  call  it  the  arterial  sap  of  the  tree. 
Cuttings  of  some  species  of  trees  very  freely  emit  roots  and  leaves  ;  whilst 
others  usually  produce  a  few  leaves  only  and  then  die ;  and  others  scarcely 
exhibit  any  signs  of  life  :  but  no  cutting  ever  possesses  the  power  of  rege- 
nerating, and  adding  to  itself  vitally,  a  single  particle  of  matter,  till  it  has 
acquired  mature  and  efficient  foliage.  A  part  of  the  arterial  sap  previ- 
ously in  the  cutting  assumes  an  organic  solid  form  ;  and  the  cutting  in 
consequence  necessarily  becomes,  to  some  extent,  exhausted. 

Summer  cuttings  possess  the  advantage  of  having  mature  and  efficient 
foliage ;  but  such  foliage  is  easily  injured  or  destroyed,  and  if  it  be  not 
carefully  and  skilfully  managed,  it  dies.  These  cuttings  (such  as 
I  have  usually  seen  employed)  have  some  mature  and  efficient  foliage,  and 
other  foliage,  which  is  young  and  growing ;  and  consequently  two  distinct 
processes  are  going  on  at  the  same  time  within  them,  which  operate  in 
opposition  to  each  other.  By  the  mature  leaves,  carbon,  under  the  influ- 
ence of  light,  is  taken  up  from  the  surrounding  atmosphere,  and  arterial 
sap  is  generated.  The  young  and  immature  leaves,  on  the  contrary, 
vitiate  the  air  in  which  they  grow  by  throwing  off  carbon ;  and  they 
expend,  in  adding  to  their  own  bulk,  that  which  ought  to  be  expended 


ON    THE    PROPAGATION    OF    TREES    BY    CUTTINGS    IN    SUMMER.  341 

in  the  creation  of  shoots.  This  circumstance  respecting  the  different 
operations  of  immature  and  mature  leaves  upon  the  surrounding  air  pre- 
sented itself  to  the  early  labourers  in  pneumatic  chemistry.  Dr.  Priestley 
noticed  the  discharge  of  oxygen  gas,  or  dephlogisticated  air  (as  it  was 
then  called),  from  mature  leaves ;  Scheele  making,  as  he  supposed,  a 
similar  experiment  upon  the  young  leaves  of  germinating  beans,  found 
these  to  vitiate  air  in  which  they  grew.  These  results  were  then  supposed 
to  be  widely  at  variance  with  each  other ;  but  subsequent  experience  has 
proved  both  philosophers  to  have  been  equally  correct. 

I  possess  many  young  seedling  trees  of  the  Ulmus  campestris,  or 
suberosa,  or  glabra,  for  the  widely- vary  ing  characters  of  my  seedling 
trees  satisfy  me  that  these  three  supposed  species  are  varieties  only  of  a 
single  species.  One  of  these  seedling  plants  presented  a  form  of  growth 
which  induced  me  to  wish  to  propagate  from  it.  It  shows  a  strong  dis- 
position to  aspire  to  a  very  great  height  with  a  single  straight  stem,  and 
with  only  very  small  lateral  branches,  and  to  be  therefore  calculated  to 
afford  sound  timber  of  great  length  and  bulk,  which  is  peculiarly  valuable, 
and  difficult  to  be  obtained,  for  the  keels  of  large  ships  ;  and  the  original 
tree  is  growing  with  very  great  rapidity  in  a  poor  soil  and  cold  climate. 

The  stem  of  this  tree  near  the  ground  presented,  in  July,  many  very 
slender  shoots  about  three  inches  long.  These  were  then  pulled  off  and 
reduced  to  about  an  inch  in  length,  with  a  single  mature  leaf  upon  the 
upper  end  of  each ;  and  the  cuttings  were  then  planted  so  deeply  in  the 
soil,  that  the  buds  at  the  bases  of  the  leaves  were  but  just  visible  above 
the  surface  of  the  soil.  The  cuttings  were  then  covered  with  bell-glasses 
in  pots,  and  put  upon  the  flue  of  a  hothouse,  and  subjected  to  a  temper- 
ature of  about  80°.  Water  was  very  abundantly  given  ;  but  the  under 
surfaces  of  the  leaves  were  not  wetted.  These  were  in  the  slightest  degree 
faded,  though  they  were  wholly  exposed  to  the  sun  ;  and  roots  were 
emitted  in  about  fifteen  days.  I  subjected  a  few  cuttings,  taken  from  the 
bearing-branches  of  a  mulberry-tree,  to  the  same  mode  of  management, 
and  with  the  same  result ;  and  I  think  it  extremely  probable  that  the 
different  varieties  of  camellia,  and  trees  of  almost  every  species,  exclusive 
of  the  fir  tribe,  might  be  propagated  with  perfect  success  and  facility  by 
the  same  means. 

Evergreen  trees  of  some  species  possess  the  power  of  ripening  their 
fruit  during  winter.  The  common  ivy  and  the  loquat  are  well  known 
examples  of  this  ;  and  this  circumstance,  combined  with  many  others,  led 
me  to  infer  that  the  leaves  of  such  trees  possess  in  a  second  year  the 
same,  or  nearly  the  same  power,  as  in  the  first.  I  therefore  planted, 


342  ON    THE    PROPAGATION    OF    TREES    BY    CUTTINGS    IN    SUMMER. 

about  a  month  ago,  some  cuttings  of  the  old  double-blossomed  white  and 
Warratah  camellia,  having  reduced  the  wood  to  little  more  than  half  an 
inch  in  length,  and  cut  it  off  obliquely,  so  as  to  present  a  long  surface  of  it ; 
and  I  reduced  it  further  by  paring  it  very  thin,  at  and  near  to  its  lower 
extremities.  The  leaves  continue  to  look  perfectly  fresh ;  and  the  buds 
in  more  than  one  instance  have  produced  shoots  of  more  than  an  inch  in 
length,  and  apparently  possessing  perfect  health  and  much  vigour.  Water 
has  been  very  abundantly  given ;  because  I  conceived  that  the  flow  of 
arterial  sap  from  the  leaf  would  be  so  great,  comparatively  with  the 
quantity  of  the  bark  and  alburnum  of  the  cuttings,  as  to  preclude  the 
possibility  of  the  rooting  of  these. 

The  cuttings  above  described  present,  in  the  organisation,  a  considerable 
resemblance  to  seedling  trees  at  different  periods  of  the  growth  of  the 
latter.  The  bud  very  closely  resembles  the  plumule ;  and  the  leaf,  the 
cotyledon,  extended  into  a  seed-leaf;  and  the  organ  which  has  been 
and  is  called  a  radicle,  is  certainly  a  caudex,  and  not  a  root.  It  is 
capable  of  being  made  to  extend,  in  some  cases,  to  more  than  two 
hundred  times  its  first  length,  between  two  articulations  ;  a  power  which 
is  not  possessed  in  any  degree  by  the  roots  of  trees.  Whether  the  caudex 
of  the  cuttings  of  camellia,  above  mentioned,  have  emitted,  or  will  or  will 
not  emit  roots,  I  am  not  yet  prepared  to  decide ;  but  I  entertain  very 
confident  hopes  of  success. 


APPENDIX 


CONTAINING 


PAPERS    ON   ANIMAL   ECONOMY 


I.— ON     THE    COMPARATIVE     INFLUENCE     OF     MALE     AND     FEMALE 
PARENTS    ON   THEIR   OFFSPRING. 

[Read  before  the  ROYAL  SOCIETY,  June  22,  1809.] 

I  HAVE  been  engaged,  during  many  years,  in  experiments  on  fruit-trees, 
of  which  the  object  has  been  to  discover  the  best  means  of  forming  new 
varieties,  that  may  be  found  better  calculated  for  the  climate  of  Britain  than 
those  at  present  cultivated.  In  this  inquiry  my  efforts  have  been  always 
most  successful,  when  I  propagated  from  the  males  of  one  variety  and  the 
females  of  another ;  and  I  was  enabled,  by  the  same  means,  to  ascertain 
more  accurately  than  had  previously  been  done  the  comparative  influence 
of  the  male  and  female  parent  on  the  character  of  the  offspring.  The 
analogy  that  subsists  between  plants  and  animals,  in  almost  everything 
which  respects  generation,  induced  me  also  to  attend  very  minutely  to 
similar  experiments  in  which  I  engaged  on  some  species  of  animals ;  and 
as  the  repetition  of  such  experiments  would  necessarily  require  a  very 
considerable  space  of  time,  and  as  the  results  seem  to  lead  to  conclusions 
that  may  be  of  public  utility,  I  have  thought  the  following  account  suffi- 
ciently interesting  to  induce  me  to  address  it  to  you. 

Linnseus  conceived  that  the  character  of  the  male  parent  predominated 
in  the  exterior  parts  both  of  plants  and  animals ;  and  the  same  opinions 
have  been  generally  entertained  by  more  modern  naturalists.  But  the 
Swedish  philosopher  appears  to  have  been  misled  by  the  striking  pre- 
dominance of  the  character  of  the  male  parent  in  male  animals,  and  to 
have  drawn  his  conclusions  somewhat  too  generally  :  for  I  have  observed 
that  seedling  plants,  when  propagated  from  male  and  female  parents  of 


344  ON    THE    INFLUENCE    OF    MALE    AND    FEMALE    PARENTS. 

distinct  characters  and  permanent  habits,  generally,  though  with  some 
few  exceptions,  inherit  much  more  of  the  character  of  the  female  than  of 
the  male  parent ;  and  the  same  remark  is  applicable  in  some  respects  to 
the  animal  world,  as  I  shall  point  out  in  the  succeeding  narrative. 

My  experiments  were  made  on  many  different  species  of  fruit-trees  ; 
but  most  extensively,  and  under  the  most  advantageous  circumstances, 
on  the  apple-tree  ;  and  as  the  results  were  all  in  unison  with  each  other, 
it  will  be  necessary  to  trouble  you  only  with  an  account  of  some  of  the 
experiments  which  were  made  on  that  species  of  fruit-tree. 

The  apple,  or  crab  of  England,  and  of  Siberia,  however  dissimilar  in 
habit  and  character,  appear  to  constitute  a  single  species  only ;  in  which 
much  variation  has  been  effected  by  the  influence  of  climate  on  successive 
generations :  for  the  two  varieties  rarely  breed  together,  and  the  off- 
spring, whether  raised  from  the  seeds  of  the  Siberian  or  British  variety, 
were  prolific  to  a  most  exuberant  extent.  But  there  was  a  very  consider- 
able degree  of  dissimilarity  in  the  appearance  of  the  offspring ;  and  the 
leaves  and  general  habits  of  each  presented  an  obvious  prevalence  of  the 
character  of  the  female  parent.  The  buds  of  those  plants  which  had 
sprung  from  the  seeds  of  the  cultivated  apple  did  not  unfold  quite  so 
early  in  the  spring  ;  and  their  fruits  generally  exceeded  very  consider- 
ably in  size  those  which  were  produced  by  the  trees  which  derived  their 
existence  from  the  seeds  of  the  Siberian  crab.  There  was  also  a  preva- 
lence of  the  character  of  the  female  parent  in  the  form  of  the  fruit ;  but 
the  same  degree  of  prevalence  did  not  extend  to  the  quality  and  flavour 
of  the  fruit ;  for  the  richest  apple  that  I  have  ever  seen,  and  which 
afforded  expressed  juice  of  much  higher  specific  gravity  than  any  other, 
sprang  from  a  seed  of  yellow  Siberian  crab. 

The  prevalence  of  the  character  of  the  female  parent  in  the  preceding 
cases  may  possibly  be  suspected  to  have  arisen  from  some  error  or  neg- 
lect of  accuracy  in  making  the  experiments  ;  but  I  do  not  conceive  that 
any  such  errors  could  have  existed ;  for  the  trees  of  each  variety  were 
trained  to  walls,  where  they  blossomed  much  before  any  others  of  the 
same  species,  and  the  stamina  were  always  carefully  extracted,  whilst 
immature,  from  every  blossom,  which  I  intended  to  afford  seeds.  The 
remaining  blossoms  of  the  trees  were  also  totally  destroyed,  and  no  other 
blossoms,  except  those  from  which  the  pollen  was  taken,  were  ever  un- 
folded in  the  neighbourhood,  in  the  season  when  the  experiments  were 
made ;  and  I  have  also  invariably  declined  to  draw  any  conclusion  from 
the  appearance  of  a  plant  in  which  I  could  not  certainly  distinguish  some 
portion  of  the  features  and  character  of  the  supposed  male  parent. 


ON    THE    INFLUENCE    OF    MALE    AND    FEMALE    PARENTS.  345 

It  is  perhaps  also  proper  to  state,  that  the  predominance  of  the  cha- 
racter of  the  female  parent  could  scarcely  have  arisen  from  any  defective 
action  of  the  pollen  ;  for,  except  in  cases  where  superfcetation  took  place, 
I  have  invariably  found  the  effect  of  a  very  large  or  a  very  small  quantity 
of  pollen  to  be  invariably  the  same  in  its  influence  on  the  offspring  ;  and 
in  the  greater  part  of  the  experiments  from  which  I  have  drawn  the 
preceding  conclusions,  more  than  ten  times  as  much  pollen  was  deposited 
on  the  stigmata  as  could  have  been  deposited  in  unmutilated  blossoms  by 
the  ordinary  means  employed  by  nature. 

In  all  attempts  to  discriminate  the  different  influence  of  the  male 
and  female  parent  on  the  offspring  of  animals  many  difficulties  pre- 
sent themselves,  owing  to  the  intermixtures  which  have  been  made  of 
the  different  breeds  of  domesticated  animals  of  every  species,  and  the 
consequent  absence  of  all  hereditary  permanency  in  the  character  of 
each  variety.  For  under  these  circumstances,  the  offspring  will  be  very 
frequently  found  to  show  little  resemblance  either  to  its  male  or  female 
parent,  either  in  form,  or  stature,  or  colour.  It  will  therefore  be  neces- 
sary, before  I  enter  on  the  subject  of  viviparous  animals,  to  observe  that 
when  I  apply  the  terms  large  and  small  to  the  male  or  female  parent,  I 
extend  the  meaning  of  those  terms  to  the  parentage  from  which  the  male 
and  female  descend,  and  not  to  the  size  of  the  individual  only  which 
becomes  the  immediate  parent  of  the  offspring. 

Mr.  Cline  has  observed,  in  a  communication  to  the  Board  of  Agricul- 
ture, that  if  the  male  and  female  parent  differ  considerably  in  size,  the 
dimensions  of  the  foetus  at  the  birth  will  be  regulated  much  more  by  the 
size  of  the  female  than  of  the  male  parent ;  and  if  the  meaning  of  the 
terms  large  and  small  be  extended  to  the  varieties  as  well  as  to  the  indi- 
viduals, his  remark  is  perfectly  just.  But  experience  compels  me  wholly 
to  reject  the  inference  that  he  has  drawn  respecting  the  advantages  of 
propagating  from  large,  in  preference  to  small  females. 

Nature  has  given  to  the  offspring  of  many  animals  (those  of  the 
sheep,  the  cow,  and  the  mare  afford  familiar  examples)  the  power  at 
an  early  age  to  accompany  their  parents  in  flight;  and  the  legs  of 
such  animals  are  very  nearly  of  the  same  length  at  the  birth,  as  when 
they  have  attained  their  perfect  growth.  When  the  female  parent  is 
large,  and  the  foetus  consequently  so,  the  offspring  will  be  large  at  its 
birth  in  proportion  to  the  bulk  it  will  ultimately  attain,  and  its  legs  will 
thence  be  long  comparatively  with  the  depth  of  the  chest  and  shoulders. 
When,  on  the  contrary,  the  female  is  small,  and  the  foetus  so,  at  the 
birth,  the  length  of  the  legs  of  the  young  animal  will  be  short  com- 


346  ON    THE    INFLUENCE    OF     MALE    AND    FEMALE    PARENTS. 

paratively  with  the  depth  of  its  chest  and  shoulders ;  and  an  animal 
in  the  latter  form  will  be  greatly  preferable,  either  for  the  purposes  of 
labour,  or  of  food  to  mankind.  I  have  seen  this  difference  in  the  influ- 
ence of  the  male  and  female  parent  on  the  offspring  very  strikingly 
exemplified  in  the  result  of  an  attempt  to  obtain  very  large  mules  from 
the  male  ass  and  the  mare.  The  largest  females  that  could  be  procured 
were  selected,  and  the  forms  of  the  offspring,  at  the  birth,  were  perfectly 
consistent  with  the  theory  of  Mr.  Cline  ;  they  were  remarkably  large  : 
and  I  observed  that  the  length  of  their  legs,  when  they  were  only  a  few 
days  old,  very  nearly  equalled  that  of  the  legs  of  their  female  parents. 
I  examined  the  same  animals  when  five  years  old,  and  in  the  depth  of 
their  chests  and  shoulders  they  very  little  exceeded  their  male  parent ; 
and  they  were  consequently  of  little  or  no  value ;  whilst  other  mules 
which  were  obtained  from  the  same  male  parent  (a  Spanish  ass),  but 
from  mares  of  small  stature,  were  perfectly  well  proportioned.  I  have 
never  seen  the  little  mule  which  is  propagated  from  the  female  ass  and 
the  horse,  nor  even  a  delineation  or  description  of  its  form ;  but  I  do 
not  entertain  any  doubt  that  its  chest  and  shoulders  are  excessively 
deep  and  strong,  comparatively  with  the  length  of  its  legs,  and  that,  on 
account  of  this  peculiarity  in  its  form,  it  has  been  so  frequently  shown 
on  the  Continent,  under  the  name  of  a  jumart,  as  the  pretended  offspring 
of  the  mare  and  the  bull. 

In  opposing  the  theory  advanced  by  Mr.  Cline,  it  is  not  by  any  means 
my  intention  to  enter  the  lists  with  him  as  a  physiologist ;  but  as  a 
farmer  and  breeder  of  animals  of  different  species,  I  have  probably  had 
many  advantages  which  he  has  not  possessed  ;  and  my  conclusions  have 
been  drawn  from  very  extensive,  and,  I  believe,  accurate  observation. 

There  is  another  respect  in  which  the  powers  of  the  female  appear  to 
be  prevalent  in  their  influence  on  the  offspring,  and  that  is  relative  to 
its  sex.  In  several  species  of  domesticated,  or  cultivated  animal  (I  believe 
in  all),  particular  females  are  found  to  produce  a  very  large  majority, 
and  sometimes  all  their  offspring,  of  the  same  sex;  and  I  have  proved 
repeatedly,  that,  by  dividing  a  herd  of  thirty  cows  into  three  equal  parts, 
I  could  calculate,  with  confidence,  upon  a  large  majority  of  females  from 
one  part,  of  males  from  another,  and  upon  nearly  an  equal  number  of 
males  and  females  from  the  remainder.  I  frequently  endeavoured  to 
change  these  habits  by  changing  the  male,  but  always  without  success  ; 
and  I  have  in  some  instances  observed  the  offspring  of  one  sex,  though 
obtained  from  different  males,  to  exceed  those  of  the  other  in  the  pro- 
portion of  five  or  six,  and  even  seven  to  one.  When,  on  the  contrary, 


ON    THE    INFLUENCE    OF    MALE    AND    FEMALE    PARENTS.  347 

I  have  attended  to  the  numerous  offspring  of  a  single  bull,  or  ram,  or 
horse,  I  have  never  seen  any  considerable  difference  in  the  number  of 
offspring  of  either  sex.  I  am  therefore  disposed  to  believe  that  the  sex 
of  the  offspring  is  given  by  the  female  parent ;  and  the  probability  of 
this  seems  obvious  in  fishes,  and  several  other  species  of  animals  which 
breed  in  water  ;  and  though  the  evidence  afforded  by  the  facts  adduced 
is  not  by  any  means  of  sufficient  weight  to  decide  the  question,  it 
probably  much  exceeds  all  that  can  be  placed  in  the  opposite  scale. 

In  oviparous  animals,  I  have  had  reason  to  think  the  influence  of  the 
female  parent  quite  as  great  as  amongst  the  viviparous  tribes,  though 
my  observations  have  been  more  limited  and  less  conclusive.  In  vivi- 
parous animals,  the  size  of  the  foetus  is  affected  by  the  influence  of  the 
male  parent,  and,  in  some  instances,  not  inconsiderably ;  but  the  size  and 
form  of  the  eggs  of  birds  do  not  appear  to  be  in  any  degree  changed  or 
modified  by  the  influence  of  the  male,  and  therefore  the  size  of  the 
offspring  at  the  birth  must  be  regulated  wholly  by  the  female  parent ; 
and  this  circumstance  permanently  affects  the  form  and  character  of  the 
offspring.  The  eggs  of  birds,  and  those  of  fishes  and  insects  (if  such  can 
properly  be  called  eggs),  appear  to  resemble  the  seeds  of  plants,  in  having 
their  forms  and  bulk  wholly  regulated  by  the  female  parent ;  but  never- 
theless their  formation  appears  to  depend  on  very  different  laws.  For 
the  eggs  both  of  birds  and  of  fishes  and  insects  attain  their  perfect  size 
in  total  independence  of  the  male,  and  the  cicatricula,  the  vitellus,  and 
the  chalazse  have  appeared  (I  believe)  to  the  most  accurate  observers,  to 
be  as  well  organised  in  the  unimpregnated,  as  in  the  impregnated  egg  : 
in  the  seed,  on  the  contrary,  everything  relative  to  its  internal  organisa- 
tion appears  dependent  on  the  male  parent.  Spallanzani  has,  however, 
stated,  that  many  plants  produced  well-organised  seeds,  and  even  seeds 
which  vegetated  perfectly,  under  circumstances  in  which  it  is  not  easy  to 
conceive  how  the  pollen  of  the  male  plant  or  flower  could  have  been 
present.  But  the  Italian  naturalist  appears  to  have  blundered  most 
egregiously  in  his  experiment;  or  (which  I  conceive  to  be  more  probable) 
he  became  the  dupe  of  the  refined  malice  of  his  countrymen ;  for  I 
repeated  his  experiments  under  very  favourable  circumstances,  and  with 
the  closest  attention,  but  I  failed  to  obtain  a  single  seed.  The  gourd 
alone  produced  apparently  perfect  fruit,  and  the  seed-coats  acquired  their 
natural  size  and  form;  and  in  this  respect  the  growth  of  its  seeds 
appeared  to  be,  like  that  of  eggs,  wholly  independent  of  the  influence  of 
the  male.  But  the  seed-coats  of  the  gourd  were  perfectly  empty,  and  I 
could  not  discover,  at  any  period  of  their  growth,  the  slightest  vestige 


348  ON    THE    INFLUENCE    OF    MALE    AND    FEMALE    PARENTS. 

either  of  cotyledons,  or  plumule,  nor  of  anything  that  appeared  to 
correspond  with  internal  organisation  of  a  seed  of  the  same  plant  under 
different  circumstances.  Spallanzani,  has  not  I  believe,  mentioned  the 
species  of  gourd  upon  which  he  made  his  experiments :  the  common,  or 
orange  gourd  of  our  gardens,  was  the  subject  of  mine. 

In  comparing  the  mode  of  the  formation  and  growth  of  eggs  with 
the  observations  I  had  previously  made  on  the  growth  of  seeds,  I 
have  been  favoured  with  the  very  able  assistance  of  Mr.  Carlisle,  for 
which  I  have  on  this,  as  on  many  other  occasions,  to  acknowledge  much 
obligation. 


II.— ON   THE    ECONOMY    OF  BEES. 
[Read  before  the  ROYAL  SOCIETY,  May  }4th,  1807.} 

IN  the  prosecution  of  those  experiments  on  trees,  accounts  of  which 
you  have  so  often  done  me  the  honour  to  present  to  the  Royal  Society, 
my  residence  has  necessarily  been  almost  wholly  confined  to  the  same  spot ; 
and  I  have  thence  been  induced  to  pay  considerable  attention  to  the 
economy  of  bees  amongst  other  objects ;  and  as  some  interesting  circum- 
stances in  the  habit  of  these  singular  insects  appear  to  have  come  under 
my  observation,  and  to  have  escaped  the  notice  of  former  writers,  I  take 
the  liberty  to  communicate  my  observations  to  you. 

It  is,  I  believe,  generally  supposed  that  each  hive  or  swarm  of  these 
insects  remains  at  all  times  wholly  unconnected  with  other  colonies  in  the 
vicinity,  and  that  the  bee  never  distinguishes  a  stranger  from  an  enemy. 
The  circumstances  which  I  shall  proceed  to  state  will,  however,  tend  to 
prove  that  these  opinions  are  not  well  founded,  and  that  a  friendly  inter- 
course not  unfrequently  takes  place  between  different  colonies,  and  is 
productive  of  very  important  consequences  in  their  political  economy. 

Passing  through  one  of  my  orchards  rather  late  in  the  evening  in  the 
month  of  August  in  the  year  1801,  I  observed  that  several  bees  passed 
me  in  a  direct  line  from  the  hives  in  my  own  garden  to  those  in  the 
garden  of  a  cottager,  which  was  about  a  hundred  yards  distant  from  it. 
As  it  was  considerably  later  in  the  evening  than  the  time  when  bees 
usually  cease  to  labour,  I  concluded  that  something  more  than  ordinary 
was  going  forward.  Going  first  to  my  own  garden,  and  then  to  that  of 
the  cottager,  I  found  a  very  considerable  degree  of  bustle  and  agitation 
to  prevail  in  one  hive  in  each  :  every  bee  as  it  arrived  seemed  to  be 
stopped  and  questioned  at  the  mouth  of  each  hive,  but  1  could  not 


ON    THE    ECONOMY    OF    BEES.  349 

discover  anything  like  actual  resistance  or  hostility  to  take  place ; 
though  I  was  much  inclined  to  believe  the  intercourse  between  the  hives 

O 

to  be  hostile  and  predatory.  The  same  kind  of  intercourse  continued,  in 
a  greater  or  less  degree,  during  eight  succeeding  days  ;  and  though  I 
watched  them  very  closely,  nothing  occurred  to  induce  me  to  suppose 
that  their  intercourse  was  not  of  an  amicable  kind.  On  the  tenth 
morning,  however,  their  friendship  ended,  as  sudden  and  violent  friend- 
ships often  do,  in  a  quarrel ;  and  they  fought  most  furiously,  and  after 
this  there  was  no  more  visiting. 

Two  years  subsequent  to  this  period  I  observed  the  same  kind  of  inter- 
course to  take  place  between  two  hives  of  my  own  bees,  which  were 
about  two  hundred  yards  distant  from  each  other;  they  passed  from 
each  hive  to  the  other  just  as  they  did  in  the  preceding  instance,  and  a 
similar  degree  of  agitation  was  observable.  In  this  instance,  however, 
their  friendship  appeared  to  be  of  much  shorter  duration,  for  they  fought 
most  desperately  on  the  fifth  day ;  and  then,  as  in  the  last-mentioned 
case,  all  further  visiting  ceased. 

I  have  some  reason  to  believe  that  the  kind  of  intercourse  I  have 
described,  which  I  have  often  seen  and  which  is  by  no  means  uncommon, 
not  unfrequently  ends  in  a  junction  of  the  two  swarms  ;  for  one  instance 
came  under  my  observation  many  years  ago  in  which  the  labouring  bees, 
under  circumstances  perfectly  similar  to  those  I  have  described,  wholly 
disappeared,  leaving  the  drones  in  peaceable  possession  of  the  hive,  but 
without  anything  to  live  upon.  I  have  also  reasons  for  believing  that 
whenever  a  junction  of  two  swarms,  with  their  property,  is  agreed  upon, 
that  which  proposes  to  remove,  immediately  or  soon  afterwards  unites 
with  the  other  swarm,  and  returns  to  the  deserted  hive  during  the  day 
only  to  carry  off  the  honey ;  for  having  examined  at  night  a  hive  from 
which  I  suspected  the  bees  to  be  migrating,  I  found  it  without  a  single 
inhabitant.  I  was  led  to  make  the  examination  by  information  I  had 
received  from  a  very  accurate  observer,  that  all  the  bees  would  then  be 
absent.  A  very  considerable  quantity  of  honey  was  in  this  instance  left 
in  the  hive  without  any  guards  to  defend  it ;  but  I  conclude  that  the 
bees  would  have  returned  for  it,  had  it  remained  till  the  next  day. 
Whenever  the  bees  quit  their  habitation  in  this  way,  I  have  always 
observed  some  fighting  to  take  place  ;  but  I  conceived  it  to  be  between 
the  bees  of  the  adjoining  hives  and  those  which  were  removing ;  the 
former  being  attracted  by  the  scent  of  the  honey  which  the  latter  were 
carrying  off. 

On  the  farm  which  I  occupy  there  were  formerly  many  old  decayed 


350  ON    THE    ECONOMY    OF    BEES. 

trees,  the  cavities  of  which  were  frequently  occupied  by  swarms  of  bees ; 
and  when  these  were  destroyed,  a  board  was  generally  fitted  to  the 
aperture  which  had  been  made  to  extract  the  honey ;  and  the  cavity  was 
thus  prepared  for  the  reception  of  another  swarm  in  the  succeeding 
season.  Whenever  a  swarm  came,  I  constantly  observed  that,  about 
fourteen  days  previous  to  their  arrival,  a  small  number  of  bees,  varying 
from  twenty  to  fifty,  were  every  day  employed  in  examining  and  appa- 
rently in  keeping  possession  of  the  cavity ;  for  if  molested,  they  showed 
evident  signs  of  displeasure,  though  they  never  employed  their  stings  in 
defending  their  proposed  habitation.  Their  examination  was  not  confined 
to  the  cavity,  but  extended  to  the  external  parts  of  the  tree  above  ;  and 
every  dead  knot  particularly  arrested  their  attention,  as  if  they  had  been 
apprehensive  of  being  injured  by  moisture  which  this  might  admit  into 
the  cavity  below  ;  and  they  apparently  did  not  leave  any  part  of  the  bark 
near  the  cavity  unexamined.  A  part  of  the  colony  which  purposed  to 
emigrate  appeared  in  this  case  to  have  been  delegated  to  search  for  a 
proper  habitation ;  and  the  individual  who  succeeded  must  have  apparently 
had  some  means  of  conveying  information  of  his  success  to  others ;  for  it 
cannot  be  supposed  that  fifty  bees  should  each  accidentally  meet  at  and 
fix  upon  the  same  cavity,  at  a  mile  distant  from  their  hive  ;  which  I  have 
frequently  observed  them  to  do  in  a  wood  where  several  trees  were 
adapted  for  their  reception ;  and  indeed  I  observed  that  they  almost 
uniformly  selected  that  cavity  which  I  thought  best  adapted  to  their  use. 

It  not  unfrequently  happened  that  swarms  of  my  own  bees  took 
possession  of  these  cavities,  and  such  swarms  were  in  several  instances 
followed  from  my  garden  to  the  trees ;  and  they  were  observed  to  deviate 
very  little  from  the  direct  line  between  the  one  point  and  the  other ; 
which  seems  to  indicate  that  those  bees  which  had  formerly  acted  as 
purveyors  now  became  guides. 

Two  instances  came  under  my  own  observation  in  which  a  swarm  was 
received  into  a  cavity  of  which  another  swarm  had  previous  possession. 
In  the  first  instance  I  arrived  with  the  swarm,  and  I  could  not  discover 
that  the  least  opposition  was  made  to  their  entrance :  in  the  second 
instance,  observing  the  direction  that  the  swarm  took,  I  used  all  the 
expedition  I  could  to  arrive  first  at  the  tree  to  which  I  supposed  they 
were  going,  whilst  a  servant  followed  them ;  and  a  descent  of  ground 
being  in  my  favour,  and  the  wind  against  them,  I  succeeded  in  arriving 
at  the  tree  some  seconds  before  them  ;  and  I  am  perfectly  confident  that 
not  the  least  resistance  was  opposed  to  their  entrance. 

Now  it  does  not  appear  probable  that  animals  so  much  attached  to 


ON    THE    ECONOMY    OF    BEES.  351 

their  property  as  bees  are,  so  jealous  of  all  approach  towards  it,  and  so 
ready  to  sacrifice  their  lives  in  defence  of  it,  should  suffer  a  colony  of 
strangers,  with  whose  intentions  they  were  unacquainted,  to  take  posses- 
sion without  making  some  effort  to  defend  it :  nor  does  it  seem  much 
more  probable  that  the  same  animals  which  spent  so  much  time  in  examin- 
ing their  future  habitation  in  the  cases  I  have  mentioned,  should  have 
attempted  in  this  case  to  enter  without  knowing  whether  there  was  space 
sufficient  to  contain  them,  and  without  any  examination  at  all.  I  must 
therefore  infer  that  some  previous  intercourse  had  taken  place  between 
the  two  swarms,  and  that  those  in  the  possession  of  the  cavities  were 
not  unacquainted  with  the  intentions  of  their  guests ;  though  the  for- 
mation of  anything  like  an  agreement  between  the  different  parties  be 
scarcely  consistent  with  the  limitations  generally  supposed  to  be  fixed 
by  nature  to  the  instinctive  powers  of  the  brute  creation. 

Brutes  have  evidently  language ;  but  it  is  a  language  of  passion  only, 
and  not  of  ideas.  They  express  to  each  other  sentiments  of  love,  of  fear, 
and  of  anger ;  but  they  appear  to  be  wholly  incapable  of  transmitting  to 
each  other  any  ideas  they  have  received  from  the  impression  of  external 
objects.  They  convey  to  other  animals  of  their  species,  on  the  approach 
of  an  enemy,  a  sentiment  of  danger  ;  but  they  appear  wholly  incapable 
of  communicating  what  the  enemy  is,  or  the  kind  of  danger  apprehended. 
A  language  of  more  extensive  use  seems,  from  the  preceding  circum- 
stances, to  have  been  given  to  bees  ;  and  if  it  be  not  in  some  degree  a 
language  of  ideas,  it  appears  to  be  something  very  similar. 

When  a  swarm  of  bees  issue  from  the  parent  hive,  they  generally  soon 
settle  on  some  neighbouring  bush  or  tree ;  and  as  in  this  situation  they 
are  generally  not  at  all  defended  from  rain  or  cold,  it  is  often  inferred 
that  they  are  less  amply  gifted  with  those  instinctive  powers  that  direct 
to  self-preservation  than  many  other  animals.  But  their  object  in 
settling  soon  after  they  leave  the  hive  is  apparently  nothing  more  than 
to  collect  their  numbers ;  and  they  have  generally,  I  believe  always, 
another  place  to  which  they  intend  subsequently  to  go  :  and  if  the 
situation  they  select  be  not  perfectly  adapted  to  secure  them  from 
injuries,  it  is  probably,  in  almost  all  instances,  the  best  they  can  discover. 
For  I  have  very  often  observed  that  when  one  of  my  hives  was  nearly 
ready  to  swarm,  one  of  the  hollow  trees  I  have  mentioned  (and  generally 
that  best  adapted  for  the  accommodation  of  a  swarm)  was  every  day 
occupied  by  a  small  number  of  bees ;  but  that  after  the  swarm  had 
issued  from  that  hive,  and  had  taken  possession  of  another,  the  tree  was 
wholly  deserted ;  whence  I  inferred  that  the  swarm  which  would  have 


352  ON    THE    ECONOMY    OF    BEES. 

taken  possession  of  the  cavity  of  that  tree  had  relinquished  their  intended 
migration  when  a  hive  was  offered  them  at  home.  And  I  am  much 
disposed  to  doubt,  whether  it  be  not  rather  habit,  produced  by  domesti- 
cation, during  many  successive  generations,  than  anything  inherent  in 
the  nature  of  bees,  which  induces  them  to  accept  a  hive,  when  offered 
them,  in  preference  to  the  situation  they  have  previously  chosen  :  for  I 
have  noticed  the  disposition  to  migrate  to  exist  in  a  much  greater  degree 
in  some  families  of  bees  than  in  others ;  and  the  offspring  of  domes- 
ticated animals  inherit,  in  a  very  remarkable  manner,  the  acquired  habits 
of  their  parents.  In  all  animals  this  is  observable ;  but  in  the  dog  it 
exists  to  a  wonderful  extent ;  and  the  offspring  appears  to  inherit  not 
only  the  passions  and  propensities,  but  even  the  resentments,  of  the 
family  from  which  it  springs.  I  ascertained  by  repeated  experiment 
that  a  terrier  whose  parents  had  been  in  the  habit  of  fighting  with  pole- 
cats will  instantly  show  every  mark  of  anger  when  he  first  perceives  the 
scent  of  that  animal,  though  the  animal  itself  be  wholly  concealed  from 
his  sight.  A  young  spaniel  brought  up  with  the  terriers  showed  no 
marks  whatever  of  emotion  at  the  scent  of  the  polecat ;  but  it  pursued  a 
woodcock,  the  first  time  it  saw  one,  with  clamour  and  exultation  :  and  a 
young  pointer,  which  I  am  certain  had  never  seen  a  partridge,  stood 
trembling  with  anxiety,  its  eyes  fixed  and  its  muscles  rigid,  when  con- 
ducted into  the  midst  of  a  covey  of  those  birds.  Yet  each  of  these  dogs 
are  mere  varieties  of  the  same  species  ;  and  to  that  species  none  of  these 
habits  are  given  by  nature.  The  peculiarities  of  character  can  therefore 
be  traced  to  no  other  source  than  the  acquired  habits  of  the  parents, 
which  are  inherited  by  the  offspring,  and  become  what  I  shall  call 
instinctive  hereditary  propensities.  These  propensities  or  modifications 
of  the  natural  instinctive  powers  of  animals  are  capable  of  endless 
variation  and  change  ;  and  hence  their  habits  soon  become  adapted  to 
different  countries  and  different  states  of  domestication,  the  acquired 
habits  of  the  parents  being  transferred  hereditarily  to  the  offspring. 
Bees,  like  other  animals,  are  probably  susceptible  of  these  changes  of 
habit,  and  thence,  when  accustomed  through  many  generations  to  the 
hive,  in  a  country  which  does  not  afford  hollow  trees  or  other  habitations 
adapted  to  their  purpose,  they  may  become  more  dependent  on  man,  and 
rely  on  his  care  wholly  for  an  habitation  ;  but  in  situations  where  the 
cavities  of  trees  present  to  them  the  means  of  providing  for  themselves, 
I  have  found  that  they  will  discover  such  trees  in  the  closest  recesses  of 
the  woods,  and  at  an  extraordinary  distance  from  their  hives ;  and  that 
they  will  keep  possession  of  such  cavities  in  the  manner  I  have  stated  : 


ON    THE    ECONOMY    OF    BEES.  353 

and  I  am  confident  that,  under  such  circumstances,  a  swarm  never  issues 
from  the  parent  hive  without  having  previously  selected  some  such  place 
to  retire  to. 

It  has  been  remarked  by  Mr.  John  Hunter,  that  the  matter  which 
bees  carry  on  their  thighs  is  the  farina  of  plants  with  which  they  feed 
their  young,  and  not  the  substance  with  which  they  make  their  combs ; 
and  his  statement  is,  I  believe,  perfectly  correct :  but  I  have  observed 
that  they  will  also  carry  other  things  on  their  thighs.  I  frequently 
covered  the  decorticated  parts  of  trees,  on  which  I  was  making  experi- 
ments, with  a  cement  composed  of  bees- wax  and  turpentine ;  and  in  the 
autumn  I  have  frequently  observed  a  great  number  of  bees  employed  in 
carrying  off  this  substance.  They  detached  it  from  the  tree  with  their 
forceps,  and  the  little  portion  thus  obtained  was  then  transferred  by  the 
first  to  the  second  leg,  by  which  it  was  deposited  on  the  thigh  of  the 
third :  the  farina  of  plants  is  collected  and  transferred  in  the  same 
manner.  This  mixture  of  wax  and  turpentine  did  not,  however,  appear 
to  have  been  employed  in  the  formation  of  combs,  but  only  to  attach  the 
hive  to  the  board  on  which  it  was  placed,  and  probably  to  exclude  other 
insects,  and  air  during  wrinter.  Whilst  the  bees  were  employed  in  the 
collection  of  this  substance,  I  had  many  opportunities  of  observing  the 
peaceful  and  patient  disposition  of  them  as  individuals,  which  Mr, 
Hunter  has  also,  in  some  measure,  noticed.  When  one  bee  had  collected 
its  load,  and  was  just  prepared  to  take  flight,  another  often  came  behind 
it,  and  despoiled  it  of  all  it  had  collected.  A  second,  and  even  a  third, 
load  was  collected  and  lost  in  the  same  manner ;  and  still  the  patient  insect 
pursued  its  labour,  without  betraying  any  symptoms  of  impatience  or 
resentment.  When,  however,  the  hive  is  approached,  the  bee  appears 
often  to  be  the  most  irritable  of  all  animals  ;  but  a  circumstance  I  have 
observed  amongst  many  other  species  of  insects,  whose  habits  are  in  many 
respects  similar  to  those  of  bees,  induces  me  to  believe  that  the  readiness 
of  the  bees  to  attack  those  who  approach  their  hives  does  not  in  any 
degree  spring  either  from  the  sense  of  injury  or  apprehensions  of  the 
individual  who  makes  the  attack.  If  a  nest  of  wasps  be  approached 
without  alarming  its  inhabitants,  and  all  communication  be  suddenly  cut 
off  between  those  out  of  the  nest  and  those  within  it,  no  provocation  wil* 
induce  the  former  to  defend  their  nest  or  themselves.  But  if  one  escape 
from  within,  it  comes  with  a  very  different  temper,  and  appears  commis- 
sioned to  avenge  public  wrongs,  and  prepared  to  sacrifice  its  life  in  the 
execution  of  its  orders.  I  discovered  the  circumstance,  that  wasps  thus 

A  A 


ON    THE    ECONOMY    OF    BEES. 

excluded  from  their  nest  would  neither  defend  it.  nor  themselves,  at  a 
very  early  period  of  my  life ;  and  I  profited  so  often  by  the  discovery  as 
a  schoolboy,  that  I  am  quite  certain  of  the  fact  I  state ;  and  I  do  not 
entertain  any  doubt,  though  I  speak  from  experiments  less  accurately 
made,  that  the  actions  of  bees  under  similar  circumstances  would  be  the 


III.— ON    SOME    CIRCUMSTANCES  RELATING  TO  THE  ECONOMY  OF  BEES, 

[Read  before  the  ROYAL  SOCIETY,  May  22nd,  1828.] 

IN  a  paper  which  I  had  the  honour  to  address  to  the  Royal  Society 
about  twenty  years  ago  (in  the  year  1807)  upon  the  Economy  of  Bees,  I 
stated,  that  having  adapted  cavities  in  hollow  trees  for  the  reception  of 
swarms  of  those  insects,  I  had  observed  that  several  days  previous  to  the 
arrival  of  a  swarm,  a  considerable  number  of  bees  were  constantly 
employed  in  examining  the  state  of  the  tree,  and  particularly  of  every  dead 
knot  above  the  cavity  which  appeared  likely  to  admit  water  into  it.  At 
that  period  it  appeared  to  me  rather  extraordinary,  that  animals  so 
industrious  as  bees,  and  so  much  disposed  to  make  the  best  use  of  their 
time,  should,  at  that  important  season  of  the  year,  waste  so  much  of  it  in 
apparently  useless  repetitions  of  the  same  act :  for  I,  at  that  time,  sup- 
posed that  on  different  days,  and  at  different  periods  of  the  same  day,  I 
saw  only  the  same  individuals.  But  in  a  case  which  at  a  subsequent 
period  came  under  my  observation,  where  the  cavity  into  which  the  bees 

*  A  curious  circumstance  relative  to  wasps  attracted  the  notice  of  some  of  my  friends  last 
year,  and  has  not,  I  believe,  been  satisfactorily  accounted  for.  A  greater  number  of  female 
wasps  were  observed  in  different  parts  of  the  kingdom,  in  the  spring  and  early  part  of  the 
summer  of  that  year,  than  at  almost  any  former  period  ;  yet  scarcely  any  nests,  or  labouring 
wasps,  were  seen  in  the  following  autumn  ;  the  cause  of  which  I  believe  I  can  explain.  Attend- 
ing to  some  peach-trees  in  my  garden,  late  in  the  autumn  of  the  year  1805,  on  which  I  had  been 
making  experiments,  I  noticed,  during  many  successive  days,  a  vast  number  of  female  wasps, 
which  appeared  to  have  been  attracted  there  by  the  shelter  and  warmth  of  a  south  wall ;  but  I 
did  not  observe  any  males.  At  length,  during  a  warm  gleam  in  the  middle  of  one  of  the  days,  a 
single  male  appeared,  and  selected  a  female  close  to  me  ;  and  this  was  the  only  male  I  saw  in 
that  season.  The  male  wasp,  which  is  readily  distinguishable  from  the  female  and  labourer, 
by  his  long  antennae  and  shining  wings,  and  by  a  blacker  and  more  slender  body,  is  rarely  seen 
out  of  the  nest,  except  in  very  warm  days,  like  the  drone  bee  ;  and  the  nests  of  wasps,  though 
very  abundant  in  the  year  1805,  were  not  formed  till  remarkably  late  in  the  season  ;  and  thence 
I  conclude  that  the  males  had  not  acquired  maturity  till  the  weather  had  ceased  to  be  warm, 
and  that  the  females,  in  consequence,  retired  to  their  long  winter  sleep  without  having  had  any 
intercourse  with  them. 


ON    THE    ECONOMY    OF    BEES.  355 

apparently  proposed  to  enter  was  not  more  than  a  quarter  of  a  mile 
distant  from  the  hive  whence  a  swarm  were  prepared  to  emigrate,  I  wit- 
nessed a  very  rapid  change  of  the  individuals  who  visited  their  future 
contemplated  habitation  ;  and  the  number  which  in  the  course  of  three 
days  entered  it,  appeared  to  me  to  be  fully  equal  to  constitute  a  very  large 
swarm  :  and  upon  the  evidence  of  these  and  other  facts,  which  I  shall 
proceed  to  state,  I  am  much  disposed  to  infer,  that  not  a  single  labouring 
bee  ever  emigrates  in  a  swarm  without  having  seen  the  future  proposed 
habitation  of  that  swarm.  That  the  queen-bee  has  also  always  seen  her 
future  habitation,  I  am  also  much  inclined  to  believe,  as  she  is  well  known 
to  absent  herself  from  the  hive  some  time  previously  to  the  emigration  of 
a  swarm  :  though  her  object  may  be  to  meet  a  male  of  another  hive ;  for 
I  much  doubt  whether  she  ever  receives  the  embraces  of  a  brother.  The 
results  of  some  of  Huber's  experiments  are  very  favourable  to  this  conclu- 
sion, as  is  the  otherwise  excessive  number  of  male  bees  ;  and  in  both  the 
animal  and  vegetable  world,  nature  has  taken  very  ample  means  of  facili- 
tating what  the  breeders  of  improved  varieties  of  domesticated  animals 
call  cross-breeding. 

I  have  also  been  led  by  the  following  facts  to  believe,  that  not  only  the 
future  permanent  habitation  of  each  swarm,  but  the  place  where  they 
temporarily  settle,  apparently  to  collect  their  numbers,  soon  after  they 
quit  their  hive,  is  known  also  to  each  individual.  Different  families  of 
domesticated  animals  of  every  species  present  some  peculiarities  of  dispo- 
sition and  habit ;  and  the  swarms  of  the  family  of  bees  which  were  the 
subject  of  my  experiments  showed,  I  think,  more  than  an  ordinary 
disposition  to  unite,  by  two  apparently  joining  the  same  queen.  My 
attention  was  consequently  attracted  to  the  circumstances  which  preceded 
such  unions. 

The  simultaneous  movements  and  agitation  of  two  hives  had  during 
several  days  led  me  to  expect  that  a  junction  of  their  swarms  was  con- 
templated ;  and  the  two  ultimately  issued  out  almost  at  the  same  moment, 
and  instantly  united,  as  I  had  concluded  they  would.  The  weather  was 
excessively  hot ;  and  I  put  them  into  a  hive  which  was  scarcely  large 
enough  to  hold  them,  affording  them  no  further  shelter  from  the  sun  than 
I  thought  just  sufficient  to  prevent  the  melting  of  their  combs.  This 
occurred  upon  the  first  day  of  June,  and  in  the  morning  of  the  twenty- 
third  a  very  large  swarm  emigrated.  There  was  in  this,  I  believe,  nothing 
very  extraordinary  or  peculiar,  except  the  excessive  expedition  apparently 
employed  in  raising  a  second  queen. 

A  A  2 


356  ON    THE    ECONOMY    OF    BEES. 

In  the  following  year  two  other  hives  presented  similar  indications  that 
their  swarms  would  unite ;  and  being  anxious  to  ascertain  whether  such 
unions  were  accidental,  or  the  consequence  of  previous  arrangements, 
I  paid  very  close  attention  to  their  proceedings,  and  the  following  singular 
circumstances  came  under  my  observation  : — After  both  hives  had  given 
frequent  indications  that  a  swarm  was  ready  to  issue  from  each  of  them, 
one  swarm  only  rose,  and  that,  after  hovering  in  the  air  during  a  much 
longer  time  than  ordinary,  settled  upon,  and  around,  a  bush  about  twenty- 
five  yards  distant  from  the  hive  whence  they  had  issued  ;  but  instead  of 
collecting  together  into  a  compact  mass,  as  they  usually  do,  they  remained 
thinly  dispersed,  scarcely  two  being  anywhere  in  contact  with  each  other. 
In  this  state  they  continued  nearly  half  an  hour  motionless,  and  apparently 
discontented  and  sulky ;  and  they  then  gradually  began  to  rise  and 
return  home,  not  apparently  in  obedience  to  any  command  or  signal ;  for 
they  did  not  rise  more  abundantly  at  any  one  point  of  time  than  at 
another,  but  each  individual  seemed  to  go  when  tired  of  waiting. 

The  next  morning  a  swarm  issued  from  the  other  hive,  and  proceeded 
to  the  bush  upon  and  around  which  the  other  swarm  had  settled  on  the 
preceding  day,  collecting  themselves  into  a  mass  as  they  usually  do  when 
their  queen  is  present.  This  was  precisely  what  I  had  anticipated,  but  I 
was  much  disappointed  that  no  movement  or  agitation  took  place  in  the 
other  hive.  Within  a  very  few  minutes,  however,  and  very  soon  after  the 
swarm  above  mentioned  had  fully  settled,  a  very  large  number  of  bees 
suddenly  rushed  from  the  hive  to  which  the  swarm  had  returned  on  the 
preceding  day,  and  proceeded  so  directly  to  the  swarm  which  had  just 
settled,  that  their  course  was  marked  through  its  whole  extent  by  a  per- 
fectly visible  dark  and  narrow  line,  and  they  united  themselves,  without 
hovering  a  single  instant,  to  the  other  swarm.  These  circumstances,  con- 
jointly with  others  which  I  have  stated  in  my  former  communication  upon 
this  subject,  satisfied  me  that  these  unions  are  generally,  if  not  always, 
the  result  of  previous  and  perfectly  well  understood  arrangements,  though 
it  is  not  easy  to  conjecture  how  such  arrangements  can  be  made. 

I  shall  proceed  to  state  a  few  circumstances  which  appear  to  throw 
light  upon  some  of  the  phenomena  observable  in  the  mode  of  breeding  of 
bees.  It  has  long  been  known  that  these  animals  possess  the  power  of 
raising  a  queen-bee  from  any  recently -deposited  egg  which  under  ordinary 
circumstances  would  have  produced  a  labouring  bee  ;  but  whether  this 
power  extends  to  those  eggs  which,  when  deposited  in  larger  cells,  afford 
male  or  drone  bees,  has  not,  I  believe,  been  accurately  ascertained.  The 


ON    THE    ECONOMY    OF    EEES.  357 

following  circumstances  lead  me  to  believe  that  sex  is  not  given  to  the 
eggs  of  birds,  or  to  the  spawn  of  fishes  or  insects,  at  any  very  early  period 
of  their  growth. 

I  selected  early  in  winter  four  female  birds  of  the  common  duck,  which 
I  kept  apart  from  any  male  bird  of  that  or  any  kindred  species,  till  the 
period  of  their  laying  eggs  approached.  One  was  then  killed,  and  the 
largest  of  its  eggs  was  found  to  be  three  lines  in  diameter.  A  musk  drake 
(Anas  moschata)  was  then  put  into  company  with  the  three  remaining 
ducks  ;  and  from  these  I  obtained  a  numerous  offspring,  six  out  of  seven 
of  which  proved  to  be  males,  as  the  result  of  similar  previous  experiments 
(but  in  which  the  male  of  another  species  had  been  introduced  at  a  period 
when  the  growth  of  the  eggs  was  less  advanced,)  had  led  me  to  expect. 
I  repeated  the  experiment  often,  and  always  with  nearly  the  same  result, 
a  large  majority  of  male  birds  being  uniformly  produced  ;  and  hence  I 
conclude  that  the  eggs  of  birds  in  early  periods  of  their  growth  are 
without  sex. 

I  have  never  possessed  means  of  obtaining  mule  fishes ;  but  one  kind 
of  fish,  which  I  think  is  obviously  a  mule,  is  found  in  many  rivers  where 
the  common  river- trout  abounds,  and  where  a  solitary  salmon  is  sometimes 
seen.  These  formerly  existed,  in  some  seasons,  in  considerable  numbers, 
in  the  river  which  passes  near  my  residence ;  but  since  salmon  have 
become  scarce,  they  have  wholly  disappeared.  I  had  formerly  opportu- 
nities of  examining  a  large  number  of  them,  without  having  ever  found  a 
single  female.  I  have  subsequently  found  them  in  large  numbers  in  small 
mountain  rivulets  in  Wales,  below,  but  never  above,  the  lowest  cataract. 
They  are  readily  distinguished  from  the  young  salmon,  by  their  form 
being  intermediate  between  that  of  a  trout  and  of  a  salmon ;  by  their 
being  all,  or  nearly  all,  males ;  and  by  their  remaining  through  the  sum- 
mer and  autumn  in  the  rivers,  long  after  the  young  salmon  have  descended 
to  the  sea  :  they  leave  the  fresh  water  with  the  first  winter  floods,  and  I 
believe  are  not  known  ever  to  return.  In  the  north  of  England  they  are 
distinguished  by  the  name  of  wrackriders,  and  by  that  of  samlets  in  some 
other  parts.  If  these  be  mules,  as  I  do  not  entertain  any  doubt  that 
they  are,  the  spawn  of  fishes  must  be  without  sex  when  it  is  deposited  by 
the  female;  and  I  am  much  disposed  to  entertain  the  same  opinion 
respecting  the  spawn  (for  it  is  more  properly  spawn  than  eggs)  of  bees. 

I  have  frequently  witnessed  some  somewhat  analogous  circumstances  in 
the  vegetable  world,  respecting  the  sexes  of  the  blossoms  of  plants ;  and 
I  can  at  any  time  succeed  in  causing  several  kinds  of  monoecious  plants 


358  ON    THE    ECONOMY    OF    BEES. 

to  produce  solely  male  or  solely  female  blossoms.  If  heat  be,  compara- 
tively with  the  quantity  of  light  which  the  plant  receives,  excessive,  male 
flowers  only  appear ;  but  if  light  be  in  excess,  female  flowers  alone  will 
be  produced  : — the  experiments  necessary  must  of  course  be  made  with 
skill  and  accuracy. 

In  a  former  communication  to  the  Royal  Society,  "  Upon  the  compara- 
tive influence  of  the  male  and  female  parent  upon  the  character  of  the 
offspring,1'  I  have  inferred,  from  facts  there  stated,  that  the  sex  of  the 
offspring  of  some  species  of  animals  is  given  by  the  female  parent.  Sub- 
sequent experience  and  observation  have  strengthened  my  belief  in  the 
truth  of  this  inference  :  but  I  believe  the  power  of  the  female  parent  to 
be  rather  strongly  influential  than  positive,  and  that  external  causes 
operate  which  (I  have  some  reason  to  suspect)  are  not  in  all  cases  wholly 
beyond  the  reach  of  human  control. 


IV.-ON    THE    HEREDITARY   INSTINCTIVE     PROPENSITIES     OF   ANIMALS. 

[Read  before  the  ROYAL  SOCIETY,  May  25th,  1837.] 

IN  a  communication  which  I  had  the  honour  many  years  ago  to  address 
to  this  Society  upon  the  Economy  of  Bees,  I  gave  an  opinion  that  families 
of  those  insects,  in  common  with  those  of  every  species  of  domesticated 
animal,  are  to  a  greater  or  less  extent  governed  by  a  power  which  I  have 
there  called  "  an  instinctive  hereditary  propensity ;""  that  is,  by  an  irre- 
sistible propensity  to  do  that  which  their  predecessors  of  the  same  family 
have  been  taught  or  constrained  to  do,  through  many  successive  genera- 
tions. In  that  communication  I  stated  that  a  young  terrier  whose 
parents  had  been  much  employed  in  destroying  polecats,  and  a  young 
springing  spaniel  whose  ancestry  through  many  generations  had  been 
employed  in  finding  woodcocks,  were  reared  together  as  companions,  the 
terrier  not  having  been  permitted  to  see  a  polecat,  or  any  other  animal 
of  similar  character,  and  the  spaniel  having  been  prevented  seeing  a 
woodcock,  or  other  kind  of  game  ;  and  that  the  terrier  evinced,  as  soon 
as  it  perceived  the  scent  of  the  polecat,  very  violent  anger ;  and  as  soon 
as  it  saw  the  polecat,  attacked  it  with  the  same  degree  of  fury  as  its 
parents  would  have  done.  The  young  spaniel,  on  the  contrary,  looked  on 
with  indifference ;  but  it  pursued  the  first  woodcock  which  it  ever  saw 
with  joy  and  exultation,  of  which  its  companion,  the  terrier,  did  not  in 
any  degree  partake. 


ON    THE    HEREDITARY   INSTINCTIVE    PROPENSITIES    OF    ANIMALS.  359 

I  had  at  that  period  made  a  great  many  analogous  experiments,  and  I 
have  subsequently  made  a  considerable  number,  chiefly  upon  one  variety 
of  dog,  namely,  that  which  is  generally  used  in  search  of  woodcocks,  and 
is  usually  called  the  springing  spaniel.  These  experiments  were  com- 
menced nearly  sixty  years  ago,  and  occupied  a  good  deal  of  my  attention 
during  more  than  twenty  years,  and  to  a  less  extent  nearly  to  the  present 
time ;  and  as  it  does  not  appear  to  me  probable  that  any  person  is  now 
likely  to  investigate  this  subject  as  laboriously,  or  through  so  long  a 
period,  I  have  been  induced  to  believe  that  the  facts  which  I  am  prepared 
to  communicate  may  be  thought  to  deserve  to  be  recorded  in  the  Trans- 
actions of  this  Society. 

At  the  period  in  which  my  experiments  commenced,  well-bred  and 
well-taught  springing  spaniels  were  abundant,  and  I  readily  obtained 
possession  of  as  many  as  I  wanted.  I  had  at  first  no  other  object  in  view 
than  that  of  obtaining  dogs  of  great  excellence ;  but  within  a  very  short 
time  some  facts  came  under  my  observation  which  very  strongly  arrested 
my  attention.  In  several  instances  young  and  wholly  inexperienced  dogs 
appeared  very  nearly  as  expert  in  finding  woodcocks  as  their  experienced 
parents.  The  woods  in  which  I  was  accustomed  to  shoot  did  not  contain 
pheasants,  nor  much  game  of  any  other  kind,  and  I  therefore  resolved 
never  to  shoot  at  anything  except  woodcocks,  conceiving  that  by  so  doing 
the  hereditary  propensities  above  mentioned  would  become  more  obvious 
and  decided  in  the  young  and  untaught  animals ;  and  I  had  the  satis- 
faction, in  more  than  one  instance,  to  see  some  of  those  find  as  many 
woodcocks,  and  give  tongue  as  correctly,  as  the  best  of  my  older  dogs. 

Woodcocks  are  driven  in  frosty  weather,  as  is  well  known,  to  seek  their 
food  in  springs  and  rills  of  unfrozen  water,  and  I  found  that  my  old  dogs 
knew  about  as  well  as  I  did  the  degree  of  frost  which  would  drive  the 
woodcocks  to  such  places  ;  and  this  knowledge  proved  very  troublesome 
to  me,  for  I  could  not  sufficiently  restrain  them.  I  therefore  left  the  old 
experienced  dogs  at  home,  and  took  only  the  wholly  inexperienced  young 
dogs;  but,  to  my  astonishment,  some  of  these,  in  several  instances, 
confined  themselves  as  closely  to  the  unfrozen  grounds  as  their  parents 
would  have  done.  When  I  first  observed  this,  I  suspected  that  wood- 
cocks might  have  been  upon  the  unfrozen  ground  during  the  preceding 
night,  but  I  could  not  discover  (as  I  think  I  should  have  done  had  this 
been  the  case)  any  traces  of  their  having  been  there ;  and  as  I  could  not 
do  so,  I  was  led  to  conclude  that  the  young  dogs  were  guided  by  feelings 
and  propensities  similar  to  those  of  their  parents. 


360  ON    THE    HEREDITARY    INSTINCTIVE   PROPENSITIES    OF    ANIMALS. 

The  subjects  of  my  observation  in  these  cases  were  all  the  offspring  of 
well-instructed  parents,  of  five  or  six  years  old  or  more ;  and  I  thought 
it  not  improbable  that  instinctive  hereditary  propensities  might  be 
stronger  in  these  than  in  the  offspring  of  very  young  and  inexperienced 
parents.  Experience  proved  this  opinion  to  be  well  founded,  and  led  me 
to  believe  that  these  propensities  might  be  made  to  cease  to  exist,  and 
others  be  given ;  and  that  the  same  breed  of  dogs  which  displayed  so 
strongly  an  hereditary  disposition  to  hunt  after  woodcocks  might  be 
made  ultimately  to  display  a  similar  propensity  to  hunt  after  truffles ; 
and  it  may,  I  think,  be  reasonably  doubted  whether  any  dog,  having  the 
habits  and  propensities  of  the  springing  spaniel,  would  ever  have  been 
known  if  the  art  of  shooting  birds  on  wing  had  not  been  acquired. 

I  possess  one  young  spaniel  of  which  the  male  parent,  apparently  a  well- 
bred  springing  spaniel,  had  been  taught  to  do  a  great  number  of  very  extra- 
ordinary tricks  (some  of  which  I  previously  thought  it  impossible  that  a 
dog  could  be  made  to  learn),  and  of  which  the  female  parent  was  a  well- 
taught  springing  spaniel ;  and  the  puppy  had  been  taught  before  it  came 
into  my  possession  a  part  of  the  accomplishments  of  its  male  parent. 
This  animal  possessed  a  very  singular  degree  of  acuteness  and  cunning, 
and  in  some  cases  appeared  to  be  guided  by  something  more  nearly  allied 
to  reason  than  I  have  ever  witnessed  in  any  of  the  inferior  animals.  In 
one  instance  I  had  walked  out  with  my  gun  and  a  servant,  without  any 
dog,  and  having  seen  a  woodcock,  I  sent  for  the  dog  above  mentioned, 
which  the  servant  brought  to  me.  A  month  afterwards  I  sent  my  servant 
for  it  again,  under  similar  circumstances,  when  it  acted  as  if  it  had  inferred 
that  the  track  by  which  the  servant  had  come  from  me  would  lead  it  to 
me.  It  left  my  servant  within  twenty  yards  of  my  house,  and  was  with 
me  in  a  very  few  minutes,  though  the  distance  which  it  had  to  run 
exceeded  a  mile.  I  repeated  this  experiment  at  different  times,  and 
after  considerable  intervals,  and  uniformly  with  the  same  results — the 
dog  always  coming  to  me  without  the  servant.  I  could  mention  several 
other  instances  nearly  as  singular  of  the  sagacity  of  this  animal,  which 
I  imagined  to  have  derived  its  extraordinary  powers,  in  some  degree, 
from  the  highly-cultivated  intellect  of  its  male  parent. 

I  have  witnessed  within  the  period  above  mentioned,  of  nearly  sixty 
years,  a  very  great  change  in  the  habits  of  the  woodcock.  In  the  first 
part  of  that  time,  when  it  had  recently  arrived  in  the  autumn,  it  was  very 
tame  j  it  usually  chuckled  when  disturbed,  and  took  only  a  very  short 
flight.  It  is  now,  and  has  been  during  many  years,  comparatively  a  very 


ON    THE    HEREDITARY    INSTINCTIVE    PROPENSITIES    OF    ANIMALS.  361 

wild  bird,  which  generally  rises  in  silence  and  takes  a  comparatively  long 
flight,  excited,  I  conceive,  by  increased  hereditary  fear  of  man. 

I  procured  a  puppy  of  a  breed  of  setters,  which  had  through  many 
generations  been  employed  in  setting  partridges  for  the  flight-net  only, 
and  of  whose  exploits  I  had  heard  many  very  extraordinary  accounts.  I 
employed  it  as  a  pointer  in  shooting  partridges ;  and  for  finding  coveys  of 
those  birds  in  the  open  field  I  n^fcr  saw  its  equal,  or  in  its  manner  of 
setting  them ;  but  it  would  never  set  its  game  amongst  brakes  or  hedge- 
rows. Whenever  it  found  a  bird  in  such  a  situation,  it  invariably  sat 
down  in  the  same  attitude,  and  alternately  looked  into  the  bush  and  at 
me,  seeming  to  think  that  setting  partridges  in  such  situations  was  not  a 
part  of  its  duty. 

It  is  well  known  that  very  young  pointers,  of  slow  and  indolent  breeds, 
will  point  partridges  without  any  previous  instruction  or  practice.  I  took 
one  of  those  to  a  spot  where  I  had  just  seen  a  covey  of  small  partridges 
alight,  in  August ;  and  amongst  them  I  threw  a  piece  of  bread  to  induce 
the  dog  to  move  from  my  heels,  which  it  had  very  little  disposition  to  do 
at  any  time,  except  in  search  of  something  to  eat.  On  getting  amongst 
the  partridges  and  perceiving  the  scent  of  them,  its  eyes  became  suddenly 
fixed  and  its  muscles  rigid,  and  it  stood  trembling  with  anxiety  during 
some  minutes.  I  then  caused  the  birds  to  take  wing,  at  sight  of  which  it 
exhibited  strong  symptoms  of  fear,  and  none  of  pleasure.  A  young 
springing  spaniel,  under  the  same  circumstances,  would  have  displayed 
much  joy  and  exultation  ;  and  I  do  not  doubt  but  that  the  young  pointer 
would  have  done  so  too,  if  none  of  its  ancestry  had  ever  been  beaten  for 
springing  partridges  improperly. 

The  most  extraordinary  instance  of  the  power  of  instinctive  hereditary 
propensity  which  I  have  ever  witnessed,  came  under  my  observation  in 
the  case  of  a  young  dog  of  a  variety  usually  called  retrievers.  The 
proper  office  of  these  dogs  is  that  of  finding  and  recovering  wounded 
game ;  but  they  are  often  employed  for  more  extensive  purposes,  and  are 
found  to  possess  very  great  sagacity.  I  obtained  a  very  young  puppy  *  of 
this  family,  which  was  said  to  be  exceedingly  well  bred,  and  had  been 
brought  to  me  from  a  distant  county.  I  had  walked  up  the  side  of  the 
river  which  passes  by  my  house,  in  search  of  wild  ducks,  when  the  dog 
above  mentioned  followed  me  unobserved,  and  contrary  to  my  wishes ; 
for  it  was  too  young  for  service,  not  being  then  quite  ten  months  old.  It 
had  not  received  any  other  instruction  than  that  of  being  taught  to  bring 

*  It  was  only  one  month  old  when  it  came  into  the  author's  possession. 


362  ON    THE   HEREDITARY    INSTINCTIVE   PROPENSITIES    OF    ANIMALS. 

any  floating  body  off  a  pond,  and  I  do  not  think  that  it  had  ever  done 
this  more  than  three  or  four  times.  It  walked  very  quietly  behind  my 
gamekeeper  upon  the  opposite  side  of  the  river,  and  it  looked  on  with 
apparent  indifference  whilst  I  killed  a  couple  of  mallards  and  a  widgeon ; 
but  it  leaped  into  the  river  instantly  upon  the  gamekeeper  pointing  out 
the  birds  to  it ;  and  it  brought  them  on  shore,  and  to  the  feet  of  the 
gamekeeper,  just  as  well  as  the  best-inducted  old  dog  could  have  done. 
I  subsequently  shot  a  snipe,  which  fell  into  the  middle  of  a  large  nearly 
stagnant  pool  of  water,  which  was  partially  frozen  over.  I  called  the  dog 
from  the  other  side  of  the  river,  and  caused  it  to  see  the  snipe,  which 
could  not  be  done  without  difficulty ;  but  as  soon  as  it  saw  it,  it  swam  to 
it,  brought  it  to  me,  laid  it  down  at  my  feet,  and  again  swam  through  the 
river  to  my  gamekeeper.  I  never  saw  a  dog  of  any  age  acquit  itself  so 
well,  yet  it  was  most  certainly  wholly  untaught.  I  state  the  circum- 
stances with  reluctance,  and  not  without  hesitation ;  because  I  doubt 
whether  I  could  myself  believe  them  to  be  well  founded,  upon  any  other 
evidence  than  that  of  my  own  senses  :  the  statement  is  nevertheless  most 
perfectly  correct. 

I  could  add  an  account  of  a  great  many  more  experiments  and  obser- 
vations which  were  made  with  other  varieties  of  dogs,  and  upon  other 
species  of  animals ;  but  as  all  the  facts  which  I  have  noticed  are  confir- 
mations of  the  truth  of  the  conclusions  which  I  have  drawn  from  those 
above  stated,  I  shall  state  the  result  of  one  other  experiment  only,  and 
that  solely  because  it  tends  to  establish  a  fact  which  appears  to  me  to  be 
of  a  good  deal  of  importance. 

I  stated  in  a  communication  to  this  Society  many  years  ago,  "  Upon 
the  comparative  influence  of  the  male  and  of  the  female  parent  upon 
the  offspring  of  some  species  of  animals,"  that  in  cases  where  nature 
intended  the  offspring  to  accompany  its  parent  in  flight  at  an  early  age, 
the  influence  of  the  parent  of  one  sex  upon  the  form  of  the  offspring 
differed  very  widely  from  that  of  the  other  parent ;  and  that  when  the 
female  parents  were  of  small  size  and  of  a  small  breed,  and  of  permanent 
habits,  and  the  male  of  a  large  size  and  large  breed,  and  of  permanent 
habits,  the  length  of  the  legs  of  the  foetus  was  given  by  those  of  the 
family  of  the  female  parent.  I  imported  some  Norwegian  pony  mares 
with  the  intention  of  obtaining  cross-bred  animals  between  them  and  the 
London  dray-horse ;  having  satisfied  myself  that  the  experiment  might  be 
made  without  danger  or  injury  to  the  smaller  animal.  The  bodies  and 
shoulders  of  the  cross-bred  animals  which  I  have  obtained  are  excessively 


ON    THE   HEREDITARY    INSTINCTIVE    PROPENSITIES    OP   ANIMALS.  363 

deep,  comparatively  with  the  length  of  their  legs,  which  remains 
unchanged,  except  that  the  joints  being  greatly  larger,  on  account  of  the 
greatly  increased  strength  of  the  legs,  and  being  of  the  same  form,  neces- 
sarily occupy  a  little  more  space.  The  strength  of  these  animals  appears 
to  be  very  great;  I  believe  that  they  will  prove  capable  of  drawing, 
particularly  up-hill,  as  heavy  weights  as  the  London  dray-horses,  provided 
that  they  be  made  to  draw  from  a  proper  level ;  and  I  am  quite  confident 
that  they  will  prove  capable  of  bearing  much  more  long-continued  labour 
and  living  upon  much  less  food. 

The  hereditary  propensities  of  the  offspring  of  the  Norwegian  ponies, 
whether  full  or  half-bred,  are  very  singular.  Their  ancestry  have  been  in 
the  habit  of  obeying  the  voice  of  their  riders,  and  not  the  bridle  ;  and  the 
horse-breakers  complain,  and  certainly  with  very  good  reason,  that  it  is 
impossible  to  give  them  what  is  called  a  mouth :  they  are  nevertheless 
exceedingly  docile,  and  more  than  ordinarily  obedient  where  they  under- 
stand the  commands  of  their  master.  They  appear  also  to  be  as  incapable 
of  understanding  the  use  of  hedges  as  they  are  of  bridles,  for  they  will 
walk  deliberately,  and  much  at  their  ease,  through  a  strong  hedge ;  and 
I  therefore  conclude  that  the  Norwegian  horses  are  not  in  the  habit  of 
being  restrained  by  hedges  similar  to  those  of  England. 

The  male  and  female  parent  appear  to  possess  similar  powers  of  trans- 
ferring to  their  offspring  their  hereditary  feelings  and  propensities,  except 
in  cases  where  mule  offsprings  are  produced.  In  such  cases,  I  think 
that  I  have  witnessed  a  decided  prevalence  of  the  power  of  the  male 
parent.  The  organisation  of  the  mule  which  is  obtained  by  cross-breeding 
between  the  horse  and  the  ass  is  well  known  to  be  regulated  to  a  much 
greater  extent  by  the  male  than  by  the  female  parent ;  and  its  disposition 
is,  I  have  some  reason  to  believe,  to  a  very  great  extent  given  by  its 
male  parent.  I  have  noticed  this  in  the  mule  which  is  the  offspring  of  a 
female  ass.  I  have  seen  a  few  only  of  these  animals ;  but  those  which  I 
have  seen  presented  the  expression  of  countenance  of  the  horse,  and  were 
perfect  horses  in  temper,  and  perfectly  without  the  sullenness  and  obsti- 
nacy of  the  more  common  mule.  The  results  of  such  violations  of  the 
ordinary  laws  of  nature  appear  to  be  very  various  in  different  species  of 
animals ;  and  I  should  not  here  have  introduced  the  subject,  but  that 
the  characters  of  mules  have  in  many  instances  misled  the  judgment  of 
physiologists  in  their  estimates  of  the  comparative  influence  in  ordinary 
cases  of  the  male  and  the  female  upon  the  offspring. 

Whenever  I  have  obtained  cross-bred  animals  by  propagating  from 


364  ON    THE    HEREDITARY    INSTINCTIVE    PROPENSITIES    OP   ANIMALS. 

families  of  dogs  of  different  permanent  habits,  the  hereditary  propensities 
of  the  offspring  .have  been  very  irregular,  sometimes  those  of  the  male 
and  at  other  times  those  of  the  female  parent  being  prevalent ;  and  in  one 
instance  I  saw  a  very  young  dog,  a  mixture  of  the  springing  spaniel  and 
setter,  which  dropped  upon  crossing  the  track  of  a  partridge,  as  its  male 
parent  would  have  done,  and  sprang  the  bird  in  silence ;  but  the  same 
dog  having  within  a  couple  of  hours  afterwards  found  a  woodcock,  gave 
tongue  very  freely,  and  just  as  its  female  parent  would  have  done.  Such 
cross-bred  animals  are,  however,  usually  worthless ;  and  the  experiments 
and  observations  which  I  have  made  upon  them  have  not  been  very 
numerous  or  interesting. 


INDEX. 


PAGE 

ALBURNOUS  vessels  of  trees,  on  their  inverted  action 130 

substance  descends  from  the  leaves,  and  is  secreted  by  the  inner 

bark H8,  151 

tubes  are  generated  within  the  interior  surface  of  the  bark     ...  145 

,  their,  origin  and  office 148 


Alburnum,  first  formation  of  its  vessels  117 

,  principal  substances  of  which  it  is  composed 139 

of  trees,  on  its  origin  and  office 148 

,  its  formation  affected  by  shading  the  leaves 96 

a  (lords  substance  for  both  roots  and  buds 119 

,  its  capacity  for  generating  new  bark  139 

,  its  power  of  carrying  fluids  in  various  directions  ....  134 

,  inconvertibility  of  bark  into 143 

,  its  vessels^best  adapted  for  carrying  the  sap  upwards  .  •  •  155 

,  its  deposition  increased  by  the  motion  of  trees  by  wind  .  .  .  337 

,  its  formation  in  the  leaf-stalk 102 

,  effect  of  abrading  its  surface 144 

is  killed  by  exposure  to  the  air 103 

,  substance  by  which  it  is  attached  to  the  bark 146 

affected  by  temperature  and  moisture 101 

: ,  arrangement  of  its  tubes  in  the  horse-chesnut  .  .  .  .  148 

of  the  oak,  quantity  of  water  contained  in  it 171 


Alligator  or  avocado  pear •         .     .  240 

Almond  hybridized  with  the  peach 252 

Almond-tree,  recommended  as  a  stock  for  the  peach  and  nectarine        .        .     .  209 

Amaryllis  Sarniensis 236 

,  on  its  cultivation 292 

Ammonia        .............  298 

Ammoniacal  gas  destructive  to  insects 245 

Ampelopsis  quinquefolia 164 

,  its  tendrils  closely  resemble  those  of  the  vine          .     .  165 

Animals,  on  their  hereditary  instinctive  propensities 358 


366  INDEX. 

PAGE 

Aphis                                     215 

Apple  subjected  to  experiment  in  order  to  obtain  new  varieties          .        .        .  175 

,  Cornish  gilliflower            325 

,  Downton  pippin 1 75 

Apricot 251 

,  Moor-park               222 

,  an  account  of  the  injurious  effect  of  the  plum-stock  upon  .  272 

Peche 222 

,  causes  of  the  premature  death  of  parts  of  its  branches    .      .  336 


stock 222 

BARK,  principal  substances  of  which  it  is  composed 139 

consists  of  layers  $7 

,  substances  which  compose  it  exist  in  the  cells  of  both  bark  and  alburnum     143 

reproduced  from  the  alburnum 139 

not  generated  in  all  cases  from  the  alburnum  142 

,  substance  by  which  it  is  attached  to  the  alburnum          .        .        .         .146 

of  trees,  on  its  formation  136 

,  its  vessels  and  fibres  adhere  less  firmly  to  the  alburnum  than  to  each 

other  146 

,  its  vessels  traced  to  the  extremities  of  the  roots          .        .        .         .    .  106 

,  effect  produced  on  trees  by  its  removal 118 

reproduced  from  the  surface  of  the  alburnum 137 

,  its  organization  better  adapted  for  transmitting  the  sap  towards  the  roots 

than  otherwise      ....  138 

,  its  capacity  for  generating  new  bark 139 

deprived  of  buds  cannot  generate  alburnum  1 47 

• possesses  in  a  slight  degree  the  power  of  forming  wood        .        .        .    .  103 

,  on  its  inconvertibility  into  alburnum  143 

,  experiment  on  its  transposition 144 

of  trees  do  not  transmit  coloured  infusions  150 

inner,  consequences  resulting  from  its  being  suddenly  affected  by  cold  in 

spring  286 

Barley,  retentive  of  its  early  habit  1 74 

Baskets  employed  for  preserving  the  roots  of  melon  plants  .        .         .    .  305 

Bean  37 

,  experiments  with  reference  to  the  direction  of  the  growth  of  roots  made 

with  it  159 

Bees,  on  their  economy  348,  354 

Berberry-tree  supposed  to  communicate  mildew  to  wheat  .        .        .    .  205 

Birch,  specific  gravity  of  its  sap  Ill 

Blossoms  and  fruit,  their  production  induced  in  the  potatoe          .        .        .    .  133 

Blossoms,  a  cause  of  their  formation 101 

Boletus  lacrymans  .        .        .        .         .        •         .         .        .         .     .  204 

squamosus  ...........  204 

Bottom-heat  for  pine  plants 302 


INDEX.  367 

PAGE 

Branches,  horizontal,  effects  of  gravitation  in  depressing  them,  counteracted  by 
the  same  agent  occasioning  the  formation  of  woody  matter  to  be 

greatest  on  their  under  side 127 

Branches,  their  junction  with  the  stem 141 

Budding,  union  resulting  from  the  operation  of 1 02 

of  the  walnut-tree 231 

Buds,  whence  generated .  122 

of  trees,  spring  from  their  alburnum            .         .        .        .         •        .    .  153 

• ,  their  production  by  roots 121 

under  certain  circumstances  are  produced  by  roots                .        .        .    .  156 

• ,  their  formation  in  tuberous  rooted  plants,  beneath  the  ground         .        .  104 

,  on  their  reproduction 119 

,  their  production  by  the  internal  parts  of  tubers       .....  120 

,  their  reproduction  in  biennial  plants           122 

,  existence  of  numerous  latent  ones            119 

Bulbous  roots              110 

Bulbous-rooted  plants               115 

,  their  leaves  and  roots  first  produced  in  spring  are  derived 

from  sap  generated  in  the  preceding  season        .        .        .        .        .    .  181 

,  on  their  culture             209 


Bulbs,  why  capable  of  producing  flowers  without  the  aid  of  soil  .        .    .     115 

CAMELLIA,  Warratah,  experiment  made  with  cuttings  of  it        .        .        .        .342 

Canker  in  trees  81 

Capillary  attraction 25,90,101,139 

Carbon  in  bulbs  . 116 

absorbed  by  green  fruits       ......         ...    224 

Caudex  189,  342 

Celery,  upon  its  culture  ..........    294 

Cellular  substance  generated  by  the  internal  surface  of  bark          .        .        .    .     138 

,  formation  of  vessels  in  it,  and  their  direction       .        .        .140 

- subsequently  becomes  vascular 143 

,  descending  vessels  more  readily  formed  in  it  than  ascending      138 

in  the  alburnum  and  bark  of  oak  .         .         .         .         .139 

permeable  to  the  sap 1 40 

Centrifugal  force  .  167 

Cherry,  Flemish .         .    .    277 

— ,  Kentish  .         ... 277 

,  Morello 277 

tres-fertile  .         .         ...        .         .         .         .         .         .    277 

,  Chinese,  upon  its  culture 295 

Climate  .        .        . 38 

induces  changes  in  the  habits  of  plants  173 

of  England,  upon  its  supposed  changes 307 

Climbing  plants,  explanation  of  their  growing  towards  support  .        .    .    166 

Coloured  infusions  employed  in  tracing  the  course  of  the  sap  .        .        86,  89 


368  INDEX. 

PAGE 

Comforts  and  luxuries,  their  materials  only  placed  by  jiature  within  the  reach 

of  man 172 

Cotyledons,  deposition  of  nutriment  in 115,131 

supply  nourishment  in  a  fluid  state  to  the  radicle  .        .        .127 

,  their  use 189 

Coxcomb,  on  its  cultivation     .         .         . 250 

Crab-apple  .        .        .         .        .        .        .        .        .        .         .        .    .    173 

Crab-tree,  Siberian 344 

Crambe  maritima,  formation  of  buds  within  its  fruit-stalks  .        .        .     .    120 

Cross-breeding 278 

Curl  in  potatoes 185,  197 

Cuttings,  inverted 107 

DAUCUS  carota,  experiments  made  relative  to  the  extension  of  its  roots  in 

different  soils 159 

Decortication 100 

or  ringing,  physiological  observations  upon  its  effects  on  fruit-trees   246 

employed  to  facilitate  the  emission  of  roots          ....     196 

of  trees  previous  to  felling  .         .         .         .         .         .     .     136 

Defoliation,  its  effect  on  the  growth  and  ripening  of  fruit         .        .        .         .170 

Disbudding ...    200 

Disease  in  plants  induced  by  over-stimulating  them          .        .        .         .        .178 

Dry  air  in  forcing-houses,  its  injurious  effects  305 

Dry-rot 204 

ELECTRICITY,  its  effect  on  plants 35,36 

Erica  australis          .        .        .        .        ...         .        .        .        .        .    297 

Exosmic  and  endosmic  action  of  fluids         .         .        .         .        .        .        .    .    316 

Evergreen  species  only  nourish  their  fruit  in  winter  .        .        .        .     170,  341 

FARINA  of  plants,  one  of  the  substances  carried  by  bees       .        .  .     .    353 

Female  parent,  character  of,  prevalent  in  cross-bred  plants        .         .        .         .177 
Fern,  in  a  green  state,  employed  as  a  manure  ....         194,197 

Fig-tree,  distinction  between  its  true  and  aqueous  sap  vessels  evident        .        .117 

— ,  effect  of  high  temperature  upon  239 

— ,  upon  its  culture  in  the  stove       .        .        .        .        .        .         .         .    248 

Fig,  account  of  a  method  of  obtaining  very  early  crops  of  ....     288 

,  white  Marseilles  .... 289 

—  Blanche  .        .        .....        .        ...        .        .     .    289 

Fishes  .        ...        . 357 

Fluids  in  plants,  their  first  direction  . 117 

Forcing-house,  description  of  one  for  grapes      .        .......        .179 

Forcing-houses  for  fruits,  best  mode  of  constructing  them  .        .        .     .     179 

— -,  on  their  ventilation 224 

Fraxinus  excelsior  .        .        .        .        .        .         .         .        .        .     .     146 

Fruit-trees,  periods  which  different  kinds  require  to  attain  puberty  .        .178 


INDEX.  369 

PAGE 

Fruit-trees,  upon  the  beneficial  effects  of  protecting  their  stems  from  frost  in 

early  spring          ( .  .        .286 

,  observations  on  the  proper  management  of  those  intended  to  be 

forced  very  early  in  the  ensuing  season              228 

,  cause  of  their  blossoms  becoming  abortive  in  forcing-houses    .         .  214 

,  upon  the  causes  of  the  premature  death  of  parts  of  their  branches    .  336 

in  pots,  upon  their  management          .......  254 


Fruits,  experiments  respecting  the  circulation  of  sap  within  them     ...  88 

— ,  their  organisation              89 

,  green,  absorb  carbon              224 

of  evergreen  species  of  plants  only  are  nourished  in  winter          .        .     .  170 

,  their  growth  and  flavour  injured  by  defoliation 170 

— ,  points  on  which  their  improvement  depends 172 

— ,  observations  on  the  means  of  producing  new  and  early  ones  .        .         .172 

— ,  means  of  obtaining  new  varieties  of          .        .        .        .        .        .    .  177 

— ,  their  ripening 226 

— ,  on  the  means  of  prolonging  the  duration  of  valuable  varieties  of          .     .  323 

of  the  melon,  derives  substance  from  remotely  situated  leaves           .         .  269 

Fruit-stalks  have  a  similar  organisation  to  the  branch  from  which  they  proceed  88 

Frost,  mode  of  its  action  in  bursting  trees 27 

Fungi,  parasitical,  supposed  to  enter  by  the  roots  of  trees              .        .        .    .  206 

GEBMEN,  experiments  relative  to  its  direction 124 

elongates  by  a  general  distension  of  its  parts         .        .        .        .    .  127 

Glass,  white,  preferable  to  green  for  plant-houses             266 

Grafting  of  trees,  observations  on 81 

—  of  old  pear-trees 202 

the  vine       • 258 

on  leaf  and  fruit-stalks 101 

—  on  leaf-stalks         . 191 

Grain  of  wood         ...........         25.91 

Grape,  Burgundy 176 

— ,  Chasselas  .  176,  255 

— ,  Red  Frontignan      .        .        . 176 

— ,Verdelho            255 

— ,  Sweetwater    ....                 .......  176 

Grapes,  experiments  on  grafting  bunches  of,  on  leaf-stalks        .         .        .        .109 

— ,  account  of  a  method  of  obtaining  very  early  crops  of        .        .        .    .  288 

— ,  formation  of  the  bunches  of 227 

,  cause  of  their  shrivelling 216 

— .  stalks  withering                   216 

Gravitation,  its  effects  on  the  descent  of  sap 97, 93 

—  the  most  active  cause  of  motion  in  the  descending  fluids        .        .101 

— ,  its  agency  in  the  descent  of  the  sap           107 

—  the  principal   cause  of  the  radicle  and  germen  proceeding  in 

opposite  directions ...  126 

p  R 


370  INDEX. 

PAGE 

Gravitation,  experiments  with  regard  to  its  effects  on  the  direction  of  the  radicle 

and  germen  ........         ....    124 

,  its  influence  on  the  germinating  parts  of  seeds          .        .        .    .    157 

,  its  effects  upon  the  plumules  of  germinating  seeds        .        .        .167 

,  its  tendency  to  depress  horizontal  branches,  how  counteracted      .     127 

occasions  the  deposition  of  woody  matter  on  the  under-side  of 

branches  to  be  greater  than  elsewhere 127 

,  its  effect  on  differently  organized  bodies 190 

on  the  direction  of  stems 300 

on  melons ,318 


and  light,  their  conflicting  influences  on  the  direction  of  leaves    .  306 

Guernsey  Lily,  on  its  culture 236. 292 

1  effects  of  extremes  of  temperature  on 239 

HEARTWOOD               ............  95 

Heat,  its  effect  on  the  motion  of  sap        ........  90 

,  degree  of,  necessary  to  put  the  sap  in  motion,  depends  on  the  previous 

excitement  of  the  plant 90 

,  excessive,  in  forcing-houses  during  the  night,  on  its  ill  effects        .        .213 

Heaths,  exotic,  suggestion  of  a  liquid  manure  for 213 

Horizontal  branches 101.127 

Hot  air 299 

Hotbeds,  an  account  of  some  improvements  in  their  construction       .         .     .  298 

Hot-houses,  with  curvilinear  iron  roofs,  advantages  of 245 

1  upon  the  advantages  and  disadvantages  of  curvilinear  iron  roofs  for  263 

heated  by  warm  air                                                         ...  272 

Humidity                                                                                                 .         .    .  226 

Hybrids,  observations  on                                                    .....  25 1 

INSECTS,  means  of  their  destruction             .....                 .    .  245 

— _   by  the  application  of  hot  water  .        .306 

Inverted  shoots 107 

Irrigation  of  garden  grounds,  by  means  of  tanks  or  ponds,  on  the  advantages  of  332 

Ivy       .                                                                                                             .  164 

— ,  nature  of  its  claspers,  and  their  evasion  of  light    .         .        .        .        .     .  165 

— ,  its  capability  of  maintaining,  by  particular  management,  an  independent 

form 288 

—  protects  plants  from  cold        .                         288 

LAUBUS  PERSEA 240 

Layering,  a  mode  by  which  peach  and  nectarine  trees  may  be  propagated     .     .  274 

Layers,  on  facilitating  the  emission  of  roots  from 195 

Leaves,  different  tubes  which  they  contain           117 

,  distinct  offices  of  their  surfaces       .    .         .         .         .         .         .        .97 

-  derive  not  their  first  nutriment  from  the  crude  sap          .         .        .     .  115 
,  their  mode  of  attachment 86 


INDEX.  371 

PACK 

Leaves,  their  connexion  with  the  roots 87 

— —  supposed  to  be  the  principal  agents  of  assimilation       .       . .        .         .115 

,  mature,  of  young  plants,  effect  of  their  being  destroyed          .        .     .     1 70 

elaborate  the  sap,  which  is  transformed  into  the  substance  of  plants    .     130 

generate  the  substance  of  roots         - .     153 

,  the  sole  organs  in  which  the  true  sap  is  generated         ....    200 

,  ratio  in  which  they  generate  sap .     .     192 

elaborate  the  aqueous  sap    .         .         • 129 

,  the  organs  by  which  the  crude  sap  is  changed 269 

—  perspire  most  when  they  have  attained  their  full  growth       .         .        .149 

,  different  actions  of  mature  and  immature  340 

,  young,  their  action  on  the  air  different  from  that  of  old  ones        .         .115 

,  direction  of  their  energies  in  the  latter  part  of  summer       .         ...     Ill 

,  when  shaded,  become  inefficient 321 

,  detached,  of  plants,  on  their  action 168 

,  their  efforts  to  turn  their  surface  to  the  light      .....     93.  129 

of  Mint,  roots  produced  from 270 

Leaf-stalk  154 

,  its  returning  vessels       .         .         .         .         .         .         .         .         .102 

,  grafting  performed  on  the 101 

,  bunch  of  Grapes  grafted  upon 191 

Lemon-tree,  under  high  temperature  239 

Ligature,  its  effect  in  impeding  the  return  of  sap 221 

applied  to  branches 247 

Light,  its  effect  on  the  stems  of  climbing  plants 166 

Potatoes 300 

,  its  influence  on  the  growth  of  parts  exposed  to  it  .         .         .         .160 

and  gravitation,  their  conflicting  influences  on  the  direction  of  leaves  .     .     306 

Lime  applied  for  the  destruction  of  insects 218 

Liquids,  their  exosmic  and  endosmic  action 316 

Lopping,  effect  of 114 

Lycoperdon  cancellatum,  on  the  mode  of  its  propagation       .        ,        .        .     .    217 

MAMMEA  AMERICANA 240 

Mammee-tree 240 

Mangifera  Indica  240 

Mango-tree 240 

Manure,  from  vegetable  matter,  on  the  advantages  of  employing  it  in  a  fresh 

state        .  ......  193 

,  on  its  application  in  a  liquid  form  to  plants  in  pots  .  ..211 

liquid  .....  .  241 

successfully  applied  to  a  plant  of  Erica  australis     .  .        .  297 

Medulla         .                                                   ....  86.  131.  190 

— ,  its  offices          .                                     .  .94 

— • —  not  necessary  to  the  progression  of  sap                               .  88 

,  experiments  with  regard  to  its  functions                       .  .            .87 

BR2 


372  INDEX. 

PAGE 

Medullary  processes  .  .  .  .  .  .  .     102 

originate  in  the  bark  .  .  .  .  .103 

originate  not  from  the  medulla  .  .  .  121 

improperly  so  termed         .  .  .  .  .     1 70 

Melon,  theory  respecting  vegetation  illustrated  in  its  culture         .  .        .189 

,  observations  on  its  culture  .  .  .  191.313 

,  effect  of  extremes  of  temperature  on  .  .  .  238 

' — ?  new  and  improved  method  of  cultivating  it  .  .  .    267 

,  means  for  preserving  its  roots  in  shifting  .  .  .  305 

• ,  description  of  a  pit  for  the  .  .  .  .  .261 

— ,  Persian  varieties  of,  on  their  cultivation  .  .  .        .314 

,  treatment  of  various  Persian  varieties  noticed  .  .  .    329 

,  Dampsha  .  .  .  .  .  .  .    330 

• ,  green  Hoosainee  .......    329 

,  striped  Hoosainee  ...  ...    329 

,  Ispahan  .......     315.  330.  331 

,  Rock  Canteloup     ........    270 

,  Salonica  ........     193 

Mentha  piperita  .  .  .  .  .  .  .  270 

Metallic  Oxides,  their  effects  on  vegetation         .  .  .  .  .36 

Mildew          ....  .  .  .  .  .28.  186 

,  its  cause   ........      188.  206 

,  its  nature  ........    204 

,  on  its  prevention  in  particular  cases  .....     204 

,  means  of  its  prevention  ......    206 

—  induced  by  disease  in  plants  .  .  .  .  .  208 

communicated  by  the  berberry-tree        .  .  .    205 

-  of  wheat         .....  .        .    219. 220 

Mint,  experiments  with  its  leaves  ......     169 

,  roots  produced  by  its  leaves  .  .  .  .  .        .    270 

Moisture,  probability  of  its  transmission  from  the  leaves  to  the  roots  by  the 

alburnum  ........    135 

in  hot-houses      ........    303 

Motion  of  trees,  effect  of  upon  the  circulation  of  sap  .  .  99 

in  a  particular  direction,  its  effect  on  the  stems  of  trees      .  .        .    109 

— ,  its  effect  on  the  vegetation  of  seeds        .  .  .  .  .125 

Mule-birds  .  .  .  .  .  .  .  .      .    253 

Mule-plants,  account  of  .  .  .  .  .  .  .275 

Mushrooms,  minuteness  of  their  seeds  .  .  .  .  .          205 

NECTARINE-TREE,  under  high  temperature        .....    239 

• ,  the  Imperatrice,  on  the  means  employed  in  raising  it  .      .    339 

Nettles  in  a  green  state  employed  as  a  manure  .....     194 

OAK,  its  greater  duration  in  northern  climates          .  .  .  84 

— — ,  remark  on  the  absence  of  tap-roots  in  the  .  .  .  .    129 


INDEX.  373 


PAGE 


Oak,  failure  of  the  crop  of  its  acorns               ...  .            287.  309 

Oak-timber,  observations  on  its  grain                    .            .  .  '          .          .92 

liable  to  be  mistaken  for  Spanish  chesnut         .  .                  .*]  100 

Onion,  on  its  management           .            .            .            .  .            .            .181 

Orange-trees,  effect  of  liquid  manure  upon               .            .  .            .      .    213 

• under  high  temperature  .....    239 

Oxygen  Gas  discharged  by  leaves                 .            .            .  .                  .    341 

PALMS  .........    142 

Parasitic  plants,  their  adhesive  processes  recede  from  the  light,  and  press 

against  opaque  bodies  .  .  .  .  .  .    166 

Parents,  on  the  comparative  influence  of  male  and  female  on  their  offspring       .    343 
Pastinaca  sativa,  experiments  made  relative  to  the  extension  of  its  roots  in  dif- 
ferent soils      .  .  .  .  .  .  .  .      .     159 

Peas        ..........    164 

— ,  crops  of,  preserved  from  the  attacks  of  mildew  .  .  .          207 

,  experiments  in  cross-breeding,  with  varieties  of  .  .    279 

,  green,  account  of  a  method  of  obtaining  very  early  crops  of  .  .      .312 

— ,  blue  Prussian         ........    279 

Peach,  Acton  Scott  .  .  .  .  .  .  .      .    273 

Peach- houses,  on  their  construction        .  .  .  .  .  .186 

Peach-stocks  .  .  .  .  .  .  :  .    274 

Peach-tree,  on  its  early  puberty  .  .  .  .  .     1 99 

,  upon  the  proper  mode  of  pruning  it  in  cold  and  late  situations  .      .    226 

,  grown  in  pots  .......    212 

Pear-tree,  on  its  culture        .  .  .  .  .  .  .      .    20 1 

,  its  fruitfulness  induced  .  .  .  .  .  .201 

— ,  on  the  mode  of  propagation  of  a  species  of  fungus  which  destroys  the 
leaves  and  branches  of  .......    207 

Pear,  Aston  town  ........    203 

,  St.  Germain     .......  .      .    202 

— ,  Crassane  .  .  .  .  .  .  .203 

Perspiratory  vessels  .  .  .  .  .  .  .      .      98 

Perspiration  of  trees  greatest  in  August  .  .  .  .  .110 

Pine-apple,  upon  its  culture  without  bark  or  other  hot-bed  .  .      .    242 

,  observations  on  its  culture  .  .        -    .  .  .    260 

— ,  description  of  a  pit  for  the  .  .  ,  .      .    261 

— ,  temperature  for  .  ,  .  .  .  .264 

,  on  its  cultivation  .  .  .  .  .  .      .    302 

,  on  watering  the      .  .  .  .  .  .  .    305 

— ,  black  Jamaica  .  .  .  .  .  .          304 

,  Enville       .  .  .  .  .  .  .  .303 

— ,  Green  olive      ........    304 

— ,  St.  Vincent's          .......    304 

,  White  Providence        .  .  .  .  .  .          303 

Pine-stove,  an  improvement  in  its  construction  suggested  .  .  .271 


374  INDEX. 

PAGE 

Pit,  description  of  one  for  melons  and  pine-apples  .  .  .    '261 

Plants  possess  no  degree  of  sensation       .  .  .  .  .  .163 

possess  not  a  locomotive  organisation,  therefore  the  endowment  of  sen- 
sation useless  .  .  .  .  .  .  .     164 

Pistillum,  the  termination  of  the  medulla  .  .  .  .  .88 

Plants  adapt,  to  a  certain  extent,  their  habits  to  the  circumstances  in  which  they 

are  placed       .........    173 

in  pots,  compost  for  certain  kinds  of          .....    256 

Plumule        .  .  .  .  .  .  .  .  .      .     189 

affected  by  gravitation  .  .  -    .  .  .167 

Plum-stock  .........    272 

,  height  attained  in  one  season  by  a  seedling  .  .  .    211 

Pollen,  remarks  on  its  supposed  influence  in  cross-breeding,  upon  the  colour  of 

the  seed-coats  of  plants,  and  the  quality  of  their  fruits          .  .      -    278 

Potato,  formation  of  buds  within  its  substance  .  .  .120 

-  consists  of  four.distinct  parts  .  .  .  .     104.  120 
-,  experiments  with  the          .                          .             .             .            .133.  134 

— ,  the  component  matter  of  its  tubers  previously  exists  either  in  the  stem 
or  leaves  ........     134 

made  to  produce  tubers  on  the  stem  .  .  .  .156 

,  its  runners  similar  in  organization  to  the  stem  .  .  .157 

— ,  tubers  not  obtained  from  its  fibrous  roots       .  .  .  .    156 

,  experiments  with  its  leaves .       .  .  .  .  .  .    169 

,  its  tubers  increased  by  destroying  the  fructification     .  ..183.  320 

,  a  communication  on  the  ......    183 

- — ,  remarks  on  the  disease  of  curl  in  the  .  .  .  .     185 

,  on  the  prevention  of  curl  in  the  .  .  .  .  .    197 

,  sets  taken  from  the  crown  produce  diseased  plants  .  .      .    198 

,  account  of  an  improved  method  of  raising  early  crops  of  the,  in  the 

open  ground          ........    256 

,  on  its  culture         .  ......    300.318.334 

,  an  account  of  an  economical  method  of  obtaining  very  early  crops  of  .    310 

—  affords  wholesome  nourishment  .  .  .  .  .319 

,  mode  of  raising  it  from  seed  .  .  .  .  .  322 

,  advantage  of  planting  large  tubers          ...  .    257,331 

— ,  great  produce  obtained  per  acre       .             .            .  .          .             .  335 

— ,  Lankman's          .  ....    300. 322.  334 

Propagation  of  trees  by  cuttings  in  summer             .             .             .             .  340 

Pruning  of  the  peach-tree                 .            .            .            .            .            .  226 

—  of  the  pear-tree               .......  203 

of  standard  trees                   ...                        ...  233 

of  timber  trees                ...                        ...  141 

Prunus                 ...                         .....  251 

—  Pseudo-Cerasus,  upon  its  culture      .  .  .  .  .      .    295 

QUINCE-STOCK  ........  222.  272 


INDEX.  375 

PAGE 

Quercus  robur,  formation  of  its  albumous  tubes  and  layers  .     145 

RADICLE,  at  first  incapable  of  absorbing  coloured  infusions  .      .     117 

at  first  destitute  of  albumous  tubes     .  .181 

,  experiments  relative  to  its  direction         .             .             .  .            124 

derives  the  substance  of  its  increase  from  the  cotyledons,  .     127. 131 

increases  in  length  solely  by  the  addition  of  new  parts  to  its  apex           126 

elongates  before  albumous  substances  are  generated  in  it  .            .142 

Red  Spider                            ...  .      .    215 

,  mode  of  destroying  it                                               .  306 

Resinous  matter,  in  different  parts  of  fir-trees                                     .  .    136 
Ringing                ...                                      .       130,131.136.221 

,  its  effect  on  the  vine                                                 .  .      .    123 

,  Physiological  observations  upon  its  effects         ....    246 

Roots,  on  their  origin  and  formation             .  .     153 

are  generated  by  the  leaves                                                  .  .153 

.  elongate  only  by  the  addition  of  new  parts  to  their  points         .  .    153 

,  when  alburnum  is  formed,  possess  the  power  of  producing  buds  .  .156 

of  trees,  their  diameter  less  than  that  of  the  trunk  and  branches  .      .136 

,  fibrous,  of  trees  are  of  perennial  duration    .            .            .  .            .157 

emitted  by  bulbs           .            .            .            .            .            .  .           156 

induced  by  ringing             .             .             .             .             .  .             .154 

readily  emitted  by  inverted  portions  of  trees               .  .     106 

,  effect  of  their  exposure      ....  .156 

disperse  in  every  direction        .  .     129 

,  less  obedient  to  the  law  of  gravitation  than  is  the  radicle  .  .        129. 158 

,  on  the  causes  which  influence  the  direction  of  their  growth    .  .      .    157 

,  mode  and  direction  of  their  growth           .             .             .  .            .189 

,  in  the  course  of  their  natural  dispersion,  increase  most  where  they  find 

the  best  nourishment                         .                                      .  .     129. 333 

are  not  attracted  to  any  particular  source  of  nourishment  .  .            .129 

progress  indifferently  toward  poisons  and  rich  soil        .             .  .     162 

progress  in  a  particular  direction  in  consequence  only  of  external  causes  160. 162 

,  on  facilitating  their  emission  from  layers               .            .  .            .     1 95 

,  their  growth  and  form  affected  by  the  motion  of  the  stem         .  .      .    163 

,  their  natural  decay  slower  than  that  of  branches                  .  .           83,  325 

,  fibrous             .                         .             .             .             .             .  .      .    281 

,  lateral,  cause  of  their  formation     ,             .             .             .  .             .129 

Rosa  indica               ...                                      .  .           287 

SACCHARINE  matter         .             .             .             .             .             .  .             .152 

Salix,  experiments  with  cuttings  of               .            .            .            .  .     107 

Sap  in  trees,  its  ascent      ...  24 

rises  wholly  through  the  alburnum         ....  93.  109. 131 

,  remote  cause  of  its  ascent         .            .             .             .             .  .      .       91 

of  trees,  account  of  some  experiments  on  its  ascent            .  .            .84 


376  INDEX. 

PAGE 

Sap,  the  aqueous  .  .  .  .  .      .    1 10 

— — ,  ascending  ....  ...    131 

,  its  channels  traced  by  means  of  coloured  infusions      .  .  86 

ascends  through  the  alburnum       .  .  .  .  •  .    1 60 

— ,  its  circulation  most  rapid  in  perpendicular  shoots       .  .  99 

— ,  experiments  relating  to  its  ascent  .  .  .  .149 

of  trees,  first  put  in  action  by  the  stems  and  branches  .  .    160 

,  its  ascending  force  .  .  .  .  .  .  .149 

..,  power  possessed  by  trees  of  transferring  it  from  one  tube  to  another         .      93 

,  its  transmission  in  different  directions  through  the  alburnum       .  .131 

,  conclusions  drawn  from  experiments  made  with  regard  to  its  ascent        .      96 

— — — «  becomes  altered  in  its  passage  from  the  root  to  the  leaves  .  .118 

of  trees,  chemically  changed  during  the  progress  of  vegetation  .      .214 

— —  in  trees,  experiments  and  observations  on  its  motion          .  .  .105 

,  evidence  of  its  descent  through  the  bark          .  ...    138 

,  true,  its  passage  direct  from  the  leaves  to  the  roots  .  .  .123 

of  trees,  evidence  of  its  descent  through  the  bark         ,  .  .     196 

in  the  radicle  descends  through  the  cortical  vessels  .  .142 

,  deposition  of,  in  the  cotyledons  .  .  .  .  .     189 

,  the  true,  elaborated  by  the  leaves  .  .  .  .110.  269 

,  its  returning  vessels  extend  from  the  points  of  the  leaves  to  the  extremity 

of  the  roots       .  .......      87 

,  the  true,  wholly  generated  in  the  leaves         ....    200.  246 

,  account  of  experiments  on  its  descent  in  trees       .  .  .  .97 

,  that  which  gives  existence  to  the  root  and  supplies  it  with  nourishment, 

descends  through  the  bark  .  .  .  :  .      .     1 60 

,  causes  of  its  descent  .  .  .  .  .  .  .97 

elaborated  in  the  leaves,  descends  by  the  bark  .  .     139 

deposited  in  the  alburnum  .  .  .  .  .  .114 

,  true,  remarks  on  the  probability  of  its  descent  through  the  alburnum  as 

well  as  by  the  bark  .  .  .  .  .  .     119 

in  the  annual  shoot  passes  downwards  through  the  central  vessels  .     142 

— ,  its  passage  from  mature  to  young  leaves          .  .  .     170 

,  its  motion  in  the  bark  retrograde  .  .  .89 

of  trees,  observations  on  the  state  in  which  it  is  deposited  during  winter       109 

,  the  true,  supposed  to  mix  partially  with  the  ascending  current      .         1 70. 1 90 

,  effects  of  its  stagnation  by  ringing      .  ...     136 

,  descending,  effect  of  its  stagnation  in  resinous  trees  .  .  .135 

,  its  specific  gravity  increases  during  its  ascent  .  .  .     152 

,  its  specific  gravity  in  trees  .  ..Ill 

,  effect  of  heat  and  cold  on  its  motion  .      90.  93 

of  trees,  its  rise  and  fall  governed  by  temperature  .    214 

,  watery  .  .  .    340 

,  vital,  or  arterial     .  .    340 

in  annual  plants,  on  the  beneficial  effects  of  its  accumulation  .      .     328 

Sap-vessels,  texture  produced  by  their  junction  .  .141 


INDEX.  377 

PAGE 

Seeds,  their  nature  .  .....     189 

— — ,  their  channels  of  nutrition  .  .  .  •  .  .89 

,  on  the  direction  of  their  radicle  and  germen  during  the  process  of  vegetation  124 

,  their  vegetation  injured  in  some  instances  by  rich  mould  .  .  1 15 

,  their  production  tends  to  weaken  the  plant  .  .  .  .116 

,  their  non-production  tends  to  prolong  the  life  of  trees  .  84 

Seedling  plants  thrive  better  in  spring  than  in  autumn  .  .  .91 

Seed-coats,  generated  wholly  by  the  female  parent  .  .  .    177 

Seed-vessel,  its  office       .  .  .  ..  .  .  .191 

Sensation  not  to  be  traced  in  plants  .  .  .  .  .     163 

Shading  of  plants  under  glass  .  .....    266 

Shallot,  on  its  culture  .  .  .  .  .  .  .     209 

Shelter  from  winds,  its  effect  on  trees     .  .  .  .  .  .163 

Shoots,  their  elongation  and  imperfect  growth  occasioned  by  damp  heat  during 

the  night  .  .  .      .    216 

Siberian  Crab  .  .....     175 

Silver  grain  of  wood  .  .  .  .  .  .  25 

,  a  substance  similar  to  it  in  the  cores  of  fruits  .  .  90 

Soil  of  old  gardens  injurious  to  seedling  trees  .  .  .  .     178 

Solar-heat,  importance  of,  in  regard  to  the  ripening  of  forced  fruits      .  .    225 

Spade  husbandry      .  .  .  .  .  .  .  .     323 

Spanish  Chestnut  timber,  that  of  Oak  liable  to  be  mistaken  for  it          .  .100 

Specific  gravity  of  timber  felled  at  different  seasons  .  .  .     112 

—  of  Oak  .  .  .  .  .  .  .132 

of  resinous  wood  .  .  .  .  .  .  135 

Spiral  tubes         .  .  .  .  .  .  .  .  86. 90 

Stems  ..........  189 

of  fruit-trees,  beneficial  effects  of  their  being  protected  .  ..  .  287 

Strawberry  plants  on  their  preparation  for  early  forcing  .  .  .  280 

Strawberry  .  .......  252 

,  on  its  cultivation  .  .  .  .  .  283. 290 

,  production  of  a  mule  variety  of  .  .  .  .  276 

— ,  Yellow  Chili        .          .  .  .  .  .  .  285 

Stocks,  on  the  effects  of  different  kinds  in  grafting  .  .  .  .221 

,  their  adaptation  .  .  .  .  .  .  .  222 

,  the  plum,  its  effect  upon  the  Apricot  .  .  .  .  .  272 

Succulent  shoots,  cause  of  their  inclination  towards  the  light  .  .  166 

Sulphur,  flowers  of,  a  remedy  against  insects  .  .  .  .  .218 

Sycamore,  specific  gravity  of  its  sap  .  .  .  .  ..Ill 

TEMPERATURE,  moderate  variations  of  it  necessary  for  vegetation  .  .  91 

— ,  effects  of  its  unequal  distribution  throughout  the  season  .  .173 

— ,  effects  of  extremes  of  .  .  .  .  .  .  303 

of  forcing-houses  .  .  .  .  .  .  .  225 

— ,  effects  of  a  very  high  one  on  some  species  of  plants  .  .  238 

— ,  an  excessively  high  one  sustained  in  dry  air  .  .  216 


378 


INDEX. 


PAGE 

Temperature,  effect  produced  by  excess  of,  on  the  Nectarine  tree  .            .    282 

— ,  tropical         .....  .           225 

for  the  Pine  apple          ....  .    264 

,  effect  of  one  too  low  on  the  stems  of  trees  .  287 


Tendrils  of  plants,  on  the  motions  of  .  .  .  .  .     1 64 

,  their  convolute  mode  of  growth  explained  .  .  .     168 

of  Ampelopsis  quinquefolia  are  attracted  to  the  shade  .  .165 

• of  the  Vine  .  .  .  .  .  .  .      .     101 

Tissu  cellulaire        ........     137.149 

tubulaire  ........     146 

Tissue,  Cellular,  expands  and  contracts  with  change  of  temperature      .  .149 

Timber,  its  quality  affected  by  the  season  at  which  it  is  felled         .  .      .110 

,  felled  in  winter,  and  summer,  difference  in  the  specific  gravity  of        .     112 

Trees,  propagated  not  by  seeds,  inherit  the  decay  of  the  parent  stock  .      .      83 

,  component  parts  of  their  solid  portions  consist  of  very  little  earthy  matter    21 1 

,  upward  tendency  of  their  luxuriant  shoots  .  .  .  .128 

Training  of  pear-trees  ........     202 

Transplanted  standard  trees,  upon  their  pruning  and  management        .  .     233 

Tuberous  roots          .  .  .  .  .  .  .  .       .     110 

Tuberous-rooted  plants  .  .  .  .  .  .115.  132 

Tubers  analogous  to  branches  .  .  .  .  .  .      .     157 

ULMUS  mon tana,  reproduction  of  its  bark                       .  .            .137 

campestris                  .             .             .             .             .  .            .       .    341 

suberosa              ......  .    341 

glabra                                                                           .  .     341 

• montana              .            .            .            .            .            .  .            .146 

Utriculi        .            .            .            .            .  •          .            .  .                   .     137 

VARIATION,  the  constant  attendant  on  cultivation          .  .  .  .     1 72 

Vegetable  mould  applied  as  manure  .  .  .  .  .     195 

Vegetation  increases  the  susceptibility  of  cold  in  plants  .  .  .93 

— ,  concise  view  of  the  theory  respecting  it  .  .  .     189 

Ventilation          .........     264 

—  of  forcing-houses  .  .  .  .  .  .      .    224 

Vessels,  central  .......     86.121.191 

,  lateral          .........     122 

of  trees  are  generally  capable  of  an  inverted  action  with  regard  to  the 

motion  of  fluids  .  .  .  .  .  .140 

Vine  .  .  .  .  .  .  .  .  .      .      89 

,  experiments  made  with  its  shoots  .  .  .         105. 170 

relating  to  the  growth  and  direction  of  its  tendrils      .         164, 167 

in  order  to  obtain  new  varieties  of  the      .  .  .     176 

— ,  on  its  grafting       ...  .  .  .     258 

— ,  composition  for  stopping  its  bleeding  .      .     181 

— ,  adaptation  of  its  habits  to  climate  .  .  .  .173 


INDEX.  379 

PAGE 

Vine,  its  adaptation  for  being  trained  ...  .      .    338 

-  in  pots         ........        229. 255 

—  crop  resulting  from  a  large  extent  of  roots  and  ample  store  of  true  sap       .    267 
Viciafaba  .......  .  .      35 

—  made  to  root  upwards      .  .  .  .  .  .      .     159 

Virginia  creeper  .  .  .  .  .  .  .  .164 

Vital  fluid 189 

Vital  matter  forming  the  accretion  of  trees  is  previously  transmitted  through 

the  leaves         ........     168 

WALNUT-TREE,  upon  grafting  it                   .            .            .                       .      .  326 

— ,  upon  the  propagation  of  its  varieties  by  budding                       .  231 

— ,  timber  of  the           ....                         .      .  231 

Watering  of  Melons        .  .  .  .  .  .  .  .192 

the  stems  of  newly  planted  trees               .            .             .            .  235 

Water-melon,  effect  of  extremes  of  temperature  on                    .            .            .  238 

Weeping  trees  exempt  from  certain  effects  of  gravitation     .            .                   .  127 

Wet  seasons        .........  333 

Wind,  its  effect  on  exposed  trees       .                                     .                               .  163 

Wood  of  the  graft  and  stock  retain  each  their  natural  character              .            .  95 
Woody  matter,  its  greater  deposition  on  the  under  side  of  branches,  an  effect  of 

gravitation             .            .            .            .            .            .            .      .  127 

Wounds  in  trees              ...                         ....  102 

— ,  their  healing           .             .             .             .            .             .             .       .  130 

Wood-ashes,  applied  for  the  destruction  of  insects          .  .  .218 


THE    END. 


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