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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