692 
[Oct. 7, 
three times the nourishment ordinarily imbibed from the 
atmosphere under different management. 
The branches which are shortened always remain slen- 
der. By reason of the small superficies of the branch, 
and the rapidity with which the sap moves, very little of 
it is retained by the branch; and, of course, nearly the 
whole is deposited in the body of the tree. This truth, 
with the fact that the foliage remains nearly a month 
longer on the trees so shortened than on others, accounts 
for the wonderful rapidity of growth effected by this me- 
thod of pruning. The smallness of the branches is of 
advantage likewise when it is necessary to prune close to 
the stem, as the wound made by that operation is propor- 
tionally small, and may be expected to cicatrize in the 
course of three years. 
It may be worth remarking that, if the branches are 
properly shortened, trees never become what is termed 
hidebound. In the Royal Forests Lord Glenbervie had 
instruments for ripping the bark of Oaks (which never 
could increase nutrition), and for scraping off the lichens ; 
but had the branches been judiciously shortened, the 
descending sap would have been so augmented through 
means of a more healthy foliage, as to have obviated the 
disease ; as the bark expands in proportion to the quantity 
of sap carried down, and if that be abundant it soon clears 
itself of all impurities. Even mismanaged trees, on 
which a dryness of bark has occurred, may be brought to 
a proper condition in the course of three seasons. In 
cases of this kind, the distance from the body at which 
the branches are amputated must be regulated by the 
size of the tree—the larger the tree the greater the dis- 
tance. 
It has been found experimentally that trees under 18 
feet in height and 15 inches in circumference advance, 
on an average, as much, both in height and circum- 
ference, in 6 years, if the branches are properly shortened, 
as they do in 15 years if these are not shortened or are 
improperly pruned. The more trees are pruned up close 
to the stem before they are 15 feet high, their growth is 
proportionally retarded. Trees pruned close to the stem, 
when the circumference of the part is under 15 inches, 
take in damp, so that the tree, if dissected, after a certain 
period at the part where the branches have been cut, will 
be found black into the pith. This department of pruning, 
when improperly managed, is the principal cause of rot, 
more particularly in the Larch. The reason is, the 
wood in young trees is more open in texture than in older 
ones. 
Irefer the reader to my Treatises on Thinning and 
Pruning in the ‘Glasgow Farmer’s Register, 1828,’’ to 
Vol. iii. of the ‘‘ Quarterly Journal of Agriculture,” No. 
XXIX. of the same Work; to ‘ Loudon’s Gardeners’ 
Magazine,” Nov., 1841, Jan., 1842, June, 1842, Sept., 
1842, and the ‘ Gardeners’ Gazette;’’ 1842, pp,.494, 671, 
793, 718, 766, and 783; and to Sir John M. Nasmyth, 
Bart., of Posso, Peeblzsbire, Dr. Balfour, Professor of 
Botany, Glasgow, and Dr. Neill, LL.D. 
AMMONIA. 
No person can peruse the writings of the German or 
French Agricultural Chemists without being struck with 
the vast importance attributed by them to the employment 
of Nitrogen or Ammonia as a manure for plants. Lie- 
big says that, with every pound of Ammonia that evapo- 
rates, we lose 60ibs. of corn; and from Boussingault we 
learn that one pound of nitrogea increases the produce 
of a meadow 100lbs, The latter author also gives Tables 
in which the value of manure is estimated by the propor- 
tion of Ammonia contained init. Since the publication 
of Liebig’s work on Agriculture the attention of Agricul- 
turists has been directed to the employment of a variet 
of substances containing Ammonia. But I believe that 
their success has been by no means equal to the promises 
held out to them, Liebig has, I think, satisfactorily 
proved that a certain quantity of Ammonia is supplied to 
s by the rain that falls on the surface of the soil; as 
s nearly a constant quantity, if plants were unable to 
obtain their Ammonia from any other source, it would be 
necessary to supply it by artificial means if we wish to 
obtain the full amount of produce which the soil is 
capable of yielding. Buta question arises— What proof 
have we that plants are unable to supply themselves with 
Ammonia from sources unknown to us ? and how far may 
the increase of crops, by the addition of substances 
containing Ammonia, be attributed to that element ? 
f we observe the practice of the Agriculturists of this 
country we shall find that the great bulk of manure is 
applied to the Turnip crop. The dung which has col- 
lected in the yards during the winter is thrown up for some 
weeks, during which time a large proportion of Ammonia 
escapes into the air; but at the same time, the inorganic 
matters—such as sulphates, phosphates, &c.—are reduced 
to astate which the Turnip is capable of assimilating. On 
reading Sir H. Davy’s works some years ago, I was 
induced, and I also persuaded some of my friends, to cart 
out our manure without previous fermentation ; but after 
two or three years we were obliged to return to the old 
custom, on account of the inferior crops that it produced. 
Thave since tried the fixing the Ammonia by means of 
sulphate of lime and sulphuric acid. But the success 
which attended these experiments has been so slight as to 
make it appear to me that the escape of Ammonia in dung 
is of little importance. Five proportions of good horse- 
dung, each weighing ° ewt., were placed in separate heaps ; 
one had a certain quantity of sulphuric acid added to it 
another was mixed with one bushel of caustic lime, the 
third was left alone, the fourth was converted into char- 
coal by being burnt in a close chamber, and the fifth was 
burnt to ashes. The first three remained six weeks before 
they were put into the ground; an equal space of ground 
THE GARDENERS CHRONICLE. 
was sown with Turnips, and the weight of produce was 
in each case nearly equal. 
Lime and ashes of coal and vegetables are used in 
large quantities as a substitute for dung in growing 
Turnips ; they can only act by the inorganic matter con- 
tained in them. Superphosphate and sulphate of lime 
are other substances capable of producing very large crops 
of Turnips. I found that a field sown with Turnips, 
and manured, alternate rows, with calcined and unburnt 
bones, decomposed with the same weight of sulphuric 
acid, produced equal effect. If we examine the sub- 
stances containing Ammonia which experience has 
proved to be beneficial for increasing the amount of Agri- 
cultural produce, we shall perceive that they contain 
some inorganic substance, to which their action may with 
equal probability be attributed. In Guano we have a 
substance containing from one to fifteen per cent. of 
Ammonia (part of the Ammonia combined with phospho- 
ric acid,) and a large proportion of phosphate of lime. 
This phosphate of lime is in a state similar to that which 
exists in fermented dung ; and although chemically the 
same as the phosphate of lime in burnt bones, still its 
effect upon plants would be infinitely superior. he 
nitrates of soda and potash are salts which contain 
nearly an equal proportion of nitrogen and oxygen com- 
bined with a different base; but their effect is known to 
differ on different soils, and this could hardly be the case 
if the nitrogen was the substance which produced the 
effect. On my own soil, nitrate of soda produces a 
much larger increase of grass than nitrate of potash ; but 
they are neither of them capable of producing a crop of 
Turnips. On the soil where nitrate of soda produced 
great effect, I found little benefit from the use of Nitrate 
of Ammonia, although this salt contains about forty per 
cent. of Ammonia. I published some time ago, in the 
Gardeners’ Chronicle, some experiments on the salts of 
Ammonia. Cabbage-plants were watered every other 
day with very dilute solutions of the salts of Ammonia; 
and I have repeated the experiments on a much larger 
scale upon Turnips; and although the increase of weight 
for the same weight of the salts has varied in different 
seasons, still the value of the salts has always remained 
the same. The phosphate of Ammonia was the best, 
then the sulphate, then the muriate; 4th, nitrate; 5th, 
carbonate, ‘The result of other people’s experiments, I 
think, proves phosphate of Ammonia to be one of the 
most powerful manures known. Sulphate of Ammonia is 
always found by those who have tried it, to be a very 
powerful manure, and the employment of itin Agriculture 
is rapidly increasing. The muriate has also had a consi- 
derable trial, but, I believe, with little advantage. I 
know of no experiments with the carbonate and nitrate ; 
the carbonate that I used was the solid Carbonate of 
Commerce; the results obtained from diluted gas-liquor 
cannot be considered of any value in this question, as it con- 
tains a large quantity of sulphuretted hydrogen. If it is the 
Ammonia of these salts which proves so beneficial, they 
ought to be valuable in proportion to the weight of Am- 
monia contained in them, which is as follows :—nitrate, 
14; nitrogen in the acid, 26—=Ammonia, 40; muriate, 31 ; 
carbonate, 28; phosphate, 25; sulphate, 22: in 100 parts. 
Whether the addition of Ammonia to the soil is neces- 
sary or not, it is certain that the employment of it on a 
soil that is deficient in the salts of phosphoric and sul- 
phuric acid must be useless ; and the system pursued in 
England of taking corn-crops so repeatedly from the land, 
has rendered a great proportion of it very deficient in 
all inorganic matter ; and until this is supplied either by 
a more extended rotation of crops, or by artificial means, 
there can be no fear that the Ammonia supplied by the 
atmosphere will be insufficient for the wants of a crop. 
—J. B. Lawes. 
OBSERVATIONS ON THE NEW SYSTEM OF 
POTTING PLANTS. 
By Wm. Woop, Foreman at Messrs, Henderson’s Nursery. 
Puszic competition has of late greatly excited emu- 
lation, produced many ingenious experiments, and led 
to many valuable results, in every department of garden- 
ing. Whatever may be the balance of merit and demerit 
in the influence of Horticultural exhibitions, it is certain 
that the encouragement they have held out to practical 
men has greatly favoured that large advance which has 
been made in the production of fine plants and blossoms. 
It is on the former that the most obvious effects have 
been produced, because in attempting to attain higher 
excellence in the ultimate objects of cultivation, specia! 
attention has been called to the means of attaining a 
greater maturity of growth in connexion with uniform de- 
velopment of bloom. 
Although the periods selected for public competition are 
often unfavourable to the timely production of a particular 
class of plants, yet this very circumstance has secured a 
better knowledge of the means of meeting such exigencies. 
But the same cause has also, in conjunction with the 
attainment of superior growth, been attended with un- 
favourable effects in» over stimulating growth by an 
excessive application of fertilising agency, and by subject- 
ing plants to a higher temp than is ble to 
the production of bloom. 
Though it is almost universally understood that any 
course of treatment which tends to cause an excessive 
development of parts—or, in other words, an unusual 
exuberance of growth—is unfavourable to the formation 
of bloom, yet there are instances of many splendid exotics, 
in which, without an immediate application of those prin- 
ciples which involve the requisite treatment for maturing 
each successive year’s growth, the most persevering 
cultivator will fail to realise those results which the ob- 
jects under his care are, with such principles in view, 
calculated to produce. It would appear almost unneces- 
sary to urge a special attention to this point, which must 
(in theory at least) be familiar to many excellent prac- 
titioners ; but, up to the present period, it has not been 
unusual to meet with instances of cultivation, which for 
their splendid growth alone have excited admiration, but 
which are far from being equally interesting, by the pre- 
sence of that which constitutes the primary object of all 
cultivation in ornamental flowering plants. 
Instances readily occur of plants which, in consequence 
of a tardy development of leaf-buds, have caused disap- 
pointment by the scantiness or total absence of bloom 
until the attainment of several years’ growth, or some 
accidental cause has tended to retard the circulation of sap 
or diversify its currents, and has thus induced a disposi- 
tion to form flower-buds. Wistaria sinensis, in the hardy 
ornamental department; Kennedya splendens, in the 
greenhouse; and Stephanotis floribunda, Mandevilla 
suaveolens, Ipomoea tyrianthina, and Thunbergia grandi- 
flora, in the stove department, are examples where the 
natural result of luxuriant growth is a partial and uncer- 
tain bloom. 
As the present test of good cultivation is the attainment 
of the greatest constitutional vigour within a limited period; 
and as this test is proved, by repeated instances, to be 
unfavourable to a uniform development of flower-buds, 
unless such growth be regulated by principles hereafter to 
be adverted to, it becomes an inquiry of much interest to 
ascertain the means by which a certain amount of fertility 
may be attained in plants which are subjected to an exces- 
sive and continual supply of stimulants, whether planted 
out or in pots, admitting of an extensive growth on 
account of their large size. It is in illustration of the 
foregoing remarks that the following principles of Horti- 
culture are brought forward, with a view to prove that it 
is only by their application that such a proportionate 
maturity of growth can be attained as is essential to a 
uniform development of bloom. 
Ist—All flower-buds, being analogous to leaf-buds, it 
follows as a corollary, that every flower with its peduncle 
and bract is a metamorphosed branch. 
Qnd—* Whatever are the Jaws of arrangement in 
branches, with respect to each other, the same will be the 
laws of the arrangement of flowers with respect to each 
other.’”’* 
In adducing evidence in favour of these principles, it 
will be seen that the formation of flower-buds neces- 
sarily depends, as a general rule, upon the presence of 
developed leaf-buds or axillary branches, and that the 
same laws which operate in the production of the one, 
necessarily act in the production of the other, In 
corroboration of these truths, a practical instance is here 
given, which will clearly illustrate the analogy that exists 
between the first formation of a leaf-bud or axillary 
branch, and its ultimate transformation into bloom. 
The engraving represents a plant of Zichya coccinea, 
which, in the month of July, 1841, was transferred from 
a60 pot toalarge 
16 — being a 
heavy shift or 
removal at that 
advanced season. 
The plant was 
subjected with 
others similarly 
treated to the 
temperature of 
an intermediate 
house. ‘To pre- 
serve a regular 
circulation of 
moisture, a pro- 
miscuous middle 
rainage was 
used in potting, 
in addition to 
the — ordinary 
mode, and the 
texture of the 
soil was ren- 
dered more open 
by the disuse of 
its close or bind- 
ing portion. Its 
growth was lux- 
uriant and rapid, 
and 
would, 
had its 
fore- 
shoots 
been at 
encou- me = 
raged, have extended over a pyramidal trellis of two feet 
six inches in height. Finding the circulation of sap too 
rapid to permit the formation of leaf-buds by axillary 
growth, recourse was had during its progressive growth, t 
pinching off the terminal leaf-buds or fore-shoots above 
each second and third joint, which caused an equal dis- 
tribution of lateral or side branches. In thus obtaining 
an accumulated vigour, by aiding the deyelopment of leat 
buds, which ultimately became matured axillary shoots, 
the season’s growth was necessarily limited, covering the 
circular trellis to about 12 inches from the base upwards: 
The practice of removing the terminal growth at state! 
distances was adopted apart from any recognition, or ore 
knowledge, of those principles of Horticulture to which if 
was ultimately referred ; and in the following spring © 
'* Principles of Botany, 287, 288 
Ta 
Sieg 
