way 2 ain La 
a 
—— 
1843.] 
THE GARDENERS CHRONICLE, 
269 
oxygen which is escaping through the pores of the leaf, 
upon the decomposition of the carbonic acid contained in 
the water; but I now feel satisfied that we must ascribe 
them to the separation of the dissolved air, by the heating 
process as described above. Still I hope to show you 2 
partial effect produced by the decomposition of carbonic 
acid by the leaf. Arm yourselves with a little of that gift 
of patience, so essential to all farmers and experimenters ; 
and, of course, doubly essential when farmers become 
experimenters. In due time (perhaps in less than half an 
hour) you will be able to distinguish certain bubbles, which 
will make their appearance,at the cut end of the leaf, or 
else here and there upon its surface. These will increase 
in size more rapidly than the rest, and at length rise to 
the surface. After one has risen, another will imme- 
diately begin to make its appearance at the same spot. 
‘A little attention will soon convince you that these bub- 
bles have proceeded from the interior of the leaf, and we 
may, I think, allow them to be the oxygen which the leat 
has separated from the carbonic acid introduced into it. 
The interior of the leaf is composed of little invisible blad. 
ders filled with fluid; and these bladders are so packed 
together as only to touch each other here and there, and 
s to leave open spaces between them, which are filled 
with air or some other sort of gas. Especially in the 
under part of the leaf the bladders are so loosely packed 
that a very large portion of air or gas is retained there. 
This is the cause why the under surface of leaves is gene- 
rally the palest; but if the air is expelled, as I shall pre- 
sently describe how it may be, and water be allowed to 
enter, the under surface will then become as dark as the 
upper. Plunge a leaf into hot water, and the air which it 
contains will escape in bubbles from the cut end, and also 
from a few points on its surface. Sometimes a bubble 
thus driven out will be seen to adhere to the surface for a 
few seconds, and then be suddenly re-absorbed into the 
leaf. When we place leaves in water, under an air-pump, 
the air they contain escapes in bubbles with great rapidity, 
from the cut end of the leaf-stalk. If you allow the 
leaves to soak for a few hours in the tumblers, the water 
will gradually insinuate itself, either through the cut end 
of the leaf, or through the part pinched by the split 
shot, or through some accidental rupture in the skin, 
‘The water will thus displace the air, and the under surface 
will first appear to be blotched with dark spots, wherever 
it has penetrated, and at length the whole will become 
uniformly dark coloured. I refer especially to laurel 
leaves. It is after these leaves have been soaking for two 
or three days that I have witnessed the stimulating effects 
of light in exciting the functions of respiration in the most 
illustrative and convincing manner. The oxygen will 
often issue in a continued stream of little bubbles, even 
with a distinct noise, from the cut end of the leaf, or from 
some point or other upon its surface. If the hand, or 
any solid substance, be interposed between it and the sun, 
so as to cast a shadow over the leaf, the effect ceases ; but 
it is immediately renewed upon the removal of the obstacle. 
Even whilst the leaf continues tobe shaded, the stream 
of bubbles may be caused to issue afresh by throwing a 
~gleam of reflected light upon it from a looking-glass, 
‘When we happen to get a leaf into such good humour for 
these experiments, they become very amusing and in- 
structive ; indeed, the information you may thus draw 
from a common tumbler, is far more satisfying and en- 
during than any fleeting gratification that could be afforded 
you by the best shilling’s-worth of brandy and water which 
it ever yet held. Only try these simple experiments, and 
think a little about them, and the knowledge you will thus 
acquire will wonderfully assist your conceptions of the 
manner in which these functions of the leaf are carried 
on. When the leaf has become thoroughly saturated with 
water, it is very curious to see the under surface graduall 
recovering its pale tint as soon as the tumbler is placed 
in the light of the sun. When I wish to give the water a 
good dose of carbonic acid, 1 fill a vial with this gas, twist 
a piece of lead round its neck, and let it float in the 
tumbler or glass jar, with its mouth downwards. Ina 
few hours, the water will have taken up all the carbonic 
acid, a large portion of which will. however, soon escape 
from the water into the air ; still, there will be enough of 
it retained to cause the function to be renewed with fresh 
vigour, after it had ceased from want of fresh supply. I 
have had a little aquatic plant growing ina glass jar full 
of water for the last six months, on the table of my study, 
and whenever the sun falls upon it, up rise several little 
Streams of bubbles of oxygen from the edges of some of 
the leaves which happen to be torn ; but I do not perceive 
that any oxygen can be detected escaping from the sur- 
face of the sound leaves. I feel a little sceptical about 
the manner in which it is commonly asserted that car- 
bonic acid is admitted within the leaf. That some portion 
of carbonic acid must be introduced with the moisture 
imbibed by the roots, seems to be undeniable; but that 
Other portions are introduced through the very pores 
by which the steam is exhaled and the oxygen dis- 
charged, appears to me to be still open to further in- 
quiry. This, however, is a subject for Botanists to look 
into, and one that is not suited to these letters: only you 
Will observe that what I have said in illustration of the 
functions of respiration is no way affected by this part 
of the theory. It is usual to treat the effects we have 
ascribed to ‘ exhalation’ and ‘respiration’ as the results of a 
twofold action, both excited by the same stimulus of light ; 
ut I question whether it would not be preferable to con~ 
Sider them as the common eflect of a single function 
which might be appropriately termed the ‘ function of or- 
Ganisation.’ What we really observe is the simultaneous 
discharge of water and oxygen from the leaf. This effect 
is attended by the fixation of the elements of water 
(oxygen and hydrogen) with carbon, in the form of or- 
ganic matter. ButI must suppress an inclination I feel 
to discuss the subject more fully. I have before noticed 
the fact, and I cannot resist again alluding to it, that 
plants are engines or laboratories employed by the 
Creator in the great work of combining a few elements 
into a nutritious material, which is to serve for the deve- 
lopment of the whole animal creation. I am not 
acquainted with any natural law which impresses me with 
a greatér sense of wonder than this ‘function of organisa- 
tion. ere we see mere crude matter brought under 
subjection to the living principle. It is wonderful to view 
the effects of gravity retaining the planets in their orbits! 
it is wonderful to witness the magic changes which che- 
‘ical affinity can work in comy ding and d ing 
avariety of mineral substances! but to me it seems far 
more wonderful that man, and all other animals, are en- 
tirely dependent upon the leaves of plants for manufactur- 
ing materials for those bodies of corruption in which, for 
a little while, they are destined to live, and move, and have 
their being. As the hopes of the agriculturist are so 
much dependent upon the healthy performance of this 
important function, surely he ought to know at least as 
much about it as the present ignorance of science may be 
able to teach him, if he would expect to be able to shape 
his practice in accordance with the laws of nature, and not 
needlessly to set himself in hopeless opposition to them. 
e will ever find nature a kind handmaid, and ready to 
minister to his wants whilst he woos her skilfully, but a 
_ very termagant whenever he resists her rudely.”—J'rom, 
‘the ‘* Bury Post.” ate 
West-Indian Cultivation.—We extract the following 
from the Third Annual Report of the St. Philip’s Agricul- 
tural Society, on Manure applied to Sugar Canes, contained 
in the Barbadoes Globe :—Manure being a costly article in 
our economy, my attention has been turned to ascertain 
what description would be most applicable to certain soils, 
and the discovery of the qualities of soils by chemical ana- 
lysis. As there are few estates on which marl or loam may 
not be obtained, I now offer some remarks on marl, on which 
a certain author makes the following observation :—‘ That 
it may justly be called the prince of manures, both for its 
fertility and durability, as well as its being easily obtained 
and applied at a moderate cost.’ Bryan Edwards asserts 
that ‘marl is another manure of vast and general utility 
in Great Britain; it enriches the poorest land, opens the 
stiffest, and sweetens and corrects the most rank. Lands 
have been raised by the use of this manure from 2s. to 21s. 
per acre annual rent.’ There is no country wherein a 
soft unctuous marl more abounds than in Jamaica, and I 
will venture to assert that marl can be obtained here of as 
good a quality and as plentifully as in any other country. 
1 some time since saw marl applied as a manure on part 
of a field, the soil of which was a reddish brown, and the 
substratum a gritty clay; it was planted with Canes, and 
the result was a very fine first crop; the second crop did 
not realise my expectations, but this may have been from 
the ‘unfavourable season. The land was subsequently 
planted with Yams, and, so far as marl had been applied, 
the return, compared with the other part of the field, was 
considerably greater ; as well as the rotation crop, which 
was Potatoes. About 80lbs. was thrown into each hole 
of four fect square. 1 have seen a less quantity applied to 
the same kind of soil without success. An excellent and 
cheap compost may be made from the wash from our dis- 
tilleries. I carted 20 loads of field trash to my still pond, 
with what herbaceous matter I could collect about the 
mill-yard, &c., and covered it with mould, and then satu- 
rated it with returns. I repeated it twice, and in three 
months I obtained a well-digested compost, without the 
aid of cattle, amounting to eighty or more cart-loads, and 
which, in my opinion, abounded with carbonic acid gas— 
the most valuable component part of manure. The canes 
which have had the above compost applied to them are 
now the most vigorousand healthy on the estate. Another 
course adopted by me for raising cheap manure is this :— 
I planted Indian Corn on my cane banks in June; the 
November following I covered it up in the cane holes; 
jn January it was decomposed, and I drew it to the 
foot of the hole and set in the Cane plant. The year 
was unfavourable, but notwithstanding a great drought, 
the Canes were comparatively good. This I found 
to be the cheapest manure I ever applied, costing little 
more than the weeding of the field. At the September 
meeting, the following article was introduced, on im- 
ported manures, with the application of the same, as prac- 
tised by a member on his estate. I have for a long 
time remarked that the quantity of manure annually pro- 
duced on almost every estate in the island with which I 
was acquainted, had become, year by year, less and less ; 
that the state in which it was applied was crude and un- 
digested; and that the period of its application had be- 
come later and later. This seemed to mea defective 
system in our plantation management, and I became 
anxious in my inquiries as to its cause, and in compar- 
ing our present with the olden routine of agricultural 
economy. So long as our little isle was favoured with 
propitious seasons, manures of the lightest kind were found 
to be sufficient to give the Planter a satisfactory return. 
A more extended cultivation of the stable (no difficulty pre- 
senting itself in the supply of the nutriment required for the 
plant) was the consequence, and provision for the cattle, 
whether in food or grazing, wasin a great measure neglected. 
During the favourable seasons to which T have adverted, 
such is the luxuriance of Tropical vegetation, it was pos- 
sible to supply a maintenance, under such a system, for 
the stock of a plantation; but it was not possible to afford 
areturn of manure through this medium at all propor- 
tionate to the necessities of a soil under so constant a 
taxation. So long indeed as the ‘ former and latter rain’ 
visited us in their proper season, the impolicy of such 
management would not manifest itself save in a gradual 
manner ; but the effects would be found to be no less cer- 
tain in the end, by the eventual diminution of our crops. 
Instead of @ continuance of favourable seasons, three 
years of drought and trial have succeeded, and the conse- 
quence of the system pursued becomes at once visible. It 
must be admitted that the drought of the last three seasons 
has been materially instrumental in furthering the evil 
deplored, inasmuch as, in favourable weather, not only 
would a large quantity of matter be produced, but the 
very moisture would further its decomposition, and 
render the manure more actively beneficial. This 
system of mismanagement was brought under the no- 
tice of this Society, by the President, at an early stage 
of its operations, and a judicious remedial course was by 
him recommended, and has more or less been acted upon 
by members and other persons. This, however, was but 
a course of remedy, and some years must necessarily 
elapse ere its benefits could be felt. Estates having been 
for several years annually extending their cultivation, and 
decreasing their means of proper returns to their lands, 
could not in a single season recover all that seasons of 
overworking had taken from those lands ; and it there- 
fore occurred to me as likely to hasten the benefit of the 
system recommended by experimenting in some of the 
concentrated manures which have been found to act 
effectively, and which have been the means of improving 
he agricultural system of the mother country so greatly 
within the last few years. ‘Their apparent cost, however, 
somewhat staggered me in my calculations, having at that 
time little idea of the outlay attending the home manu- 
facture of manure. In order to satisfy myself, and to 
remove the objections that were stated, I*instituted a 
strict scrutiny into the labour expenditure under this 
head, and I have found that scarcely less than thirty 
dollars will supply sufficient manure for an acre of Canes ; 
and I therefore determined on writing to England for 
some Rape-dust, which had been recommended to me by 
atrial on my last crop, from which I had reaped a bene- 
ficial return. Almost at the moment of my receiving it, 
however, I met, in the English newspapers, with notices 
on “Guano,” which had then just been introduced, and 
which I found to be the manure that had for centuries 
been used in Peru and Mexico—countries which I knew 
to be scarcely ever visited by rains, and whose only me- 
dium of moisture is the “dew of night.’’ Shortly after 
meeting with these notices, a merchant of Bridgetown 
imported a quantity of this manure, and having a high 
opinion of it, as specially fitted for this country, I made up 
my mind to try it. Having a field of about six acres un- 
der preparation, I determined on manuring it with Guano 
alone, and it is gratifying to notice that the Canes in this 
field have suffered less from the drought to which they 
have been exposed than any others on either estate, whe- 
ther manured with home-made manure, with Rape-dust, 
or with anything else. In a field on White River, con- 
sisting cf nine acres, adjoining the estate on which the 
above trial was made, experiments have been made with 
“* Guano,” “ Artificial Guano,” ‘ Daniell’s Patent Ma- 
nure,” Rape-dust, and the cleanings of an old well on 
the estate, which had for the last half-century been the 
burying-place for dead stock ; and I can only say that the 
Canes to which Guano has been applied, are not only 
higher, but more vigorous than those to which any other 
manure has been applied. The Rape-dust, from expe- 
rience, I can speak of as a good manure, having reaped 
during the last crop, notwithstanding the drought, nearly 
3 hhds. sugar from about 1j acre, but itis more expen- 
sive than Guano, although not more so than our home 
manure. When, however, we call to mind the position 
of the West Indies, we must feel that the simplification 
of manual labour, whether by the introduction of machi- 
nery, or by purchase of manures at the same cost as the 
labour for the production would require, and that such a 
course would have all the effect of an increased agricul~ 
tural population, by making more labour available for 
general purposes, I think no question can be raised as to 
the expediency of making trial of such a course as would 
be productive of such ends. But the objection has been 
raised that I can only speak of the comparative *luxuri- 
ance of the growth of such Canes as have been manured 
with Guano, and that I have not yet tested the prices they 
will render?’ True, I have not yet reaped any Canes that 
have been so manured ; but if the more healthy develop- 
ment of the plant, followed by a continuance of vigour 
over those around, whether under the influence of favour- 
able or unfavourable weather, give not some promise that 
the produce will be superior, I know not what argument 
I can use in support of my opinion, that Guano is a most 
excellent manure, and that it is well suited to our general 
requirements, and calculated to hasten the grand objects 
of every planter. Your Committee further state that the 
minutes of the Society contain two communications on 
‘Agriculture ; one on “ Flat Tillage,” from J. Briggs, Esq., 
and the other on the ‘‘ Use of the Plough,” from J. 
King, Esq., as well as a paper from one of the Members, 
bearing out the former gentleman in the system of ‘‘ Flat 
Planting.” The first communication was as follows :— 
“ With a view of assisting your annual report of improve- 
ments in Agriculture, I furnish you with an account of my 
system of flat tillage for Sugar-Cane planting. The whole 
of my this year’s planting has been by relining my fields, 
making the site for each plant, and simply drilling for its 
insertion—not having turned up the soil more than was 
necessary for destroying weeds. From the land that I 
have planted, I removed the trash last year, and the lands 
that 1 intend for next year’s planting J have not removed 
any trash from ; so that this year’s planting labours un- 
der bad privation. Otherwise, I have afforded my plants 
every advantage of manuring, that the property admitted 
