254 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ September 20 1585 
name implies, it is composed of carbon and oxygen, C 0 2 . Take a 
piece of charcoal and ignite it. It burns. What is this burning? 
Simply, in chemical language, it is an oxidisation of the charcoal 
(carbon). The process is purely chemical. Two atoms of oxygen 
unite with one (this is scarcely correct, but as an explanation must 
<lo here) of carbon, and a new compound is formed. This new com¬ 
pound is a gas—it is carbonic dioxide, and it escapes in the air. The 
same process occurs in the human body. We eat carbo-hydrates— 
sugar, starch—and digest them. T hen by our lungs we take in oxygen 
from the air. This oxygen by the blood finds its way all through the 
body, oxidises the carbon of the body fuel, which in the process gives 
•out heat, and is expelled by the lungs as carbonic dioxide. The 
decay of all organic matter is just this oxidisation. Plants do exactly 
the opposite of what animals, tire, and decay do. 
This carbonic dioxide in the air is the source of all the carbon in 
plants. Thence have been drawn all the humus of our soils, the peat of 
our bogs, and the coal which heats our houses and drives our engines ; 
yet its comparative amount in the atmosphere is very small, though 
in the aggregate it is enormous. Its per-centage in the air is 0 035, 
or 35 in 100,000. But it is everywhere present, and amounts in the 
aggregate to over two billion tons, a quantity that quite baffles human 
conception. When we come to consider the functions of the leaf 
and the diffusion of gases we will see that the supply of this is never 
short unless in unventilated, too closely glazed houses. 
Although, by growing them in calcined sand, it has been proved 
that plants can find all their carbon in the air and flourish without 
its presence in the soil, much is supplied from decaying animal and 
vegetable matter in the soil to plants by the roots, and without doubt 
materially assists a rapid growth ; and although 0 035 per cent, in 
the air is sufficient to maintain a vigorous growth, it has been shown 
that plants are greatly benefited when it is largely increased. When 
too much is present it is destructive even to plants ; but it may be 
present to an extent poisonous to animals and yet prove of great 
benefit to plants. Bohn conducted numerous experiments to ascertain 
the effects of carbonic acid on plants, and found it beneficial up to 
the extent of 2 per cent., over that it was injurious, and when 20 per 
■cent, was present it killed. On the other hand Godlewski asserts 
that Glyceria was benefited when as much as 8 or 10 per cent, was 
present. It is supposed that the huge stature of the Club Mosses and 
Marestails, and the exuberance of vegetation in general at the time 
-our coal beds were formed, was largely due to the much greater per¬ 
centage of the carbon in the air. Much was also due, doubtless, to 
the moistness and heat of the climate, as these when combined in our 
age never fail to induce rapid growth. Those who have read Loudon’s 
account of the poison valley of Java, where carbonic acid issues from 
the ground, will recall the fact that there vegetation is absent. 
Though an increase of carbonic dioxide in the atmosphere be im¬ 
practical, doubtless its abundant presence in the soil will have a similar 
effect on plants to what its supply in the air would. Hence manures 
which supply this, as those from leaves, straw, green manurings, animal 
dungs, &c., certainly possess an advantage over equivalent amounts 
of purely chemical ones. But a question arises : Is not this fact one 
of the causes of unfruitfulness in fruit trees in heavily manured 
garden soils ? Ail the elements of fertility otherwise may be present 
in abundance, but an excess of carbonic dioxide causes a mere excess 
of vegetation and unfruitfulness. So far as we are aware, no plants 
-capable of furnishing food to the higher animals have been found in 
the strata of the carboniferous era. Everything vegetable was too 
oarboniferous. A large per-centage of phosphorus and potash exist 
in the ash of all nutritious vegetable substances. In the ash of these 
ancient plants they are singularly deficient, as they always are in 
plants deficient in animal nutrients, and in consequence the fauna 
was composed of either Ilerbivora with huge digestive systems, or 
Carnivora preying on them. The Frugivora and Graminivora are 
singularly absent. There was no place for men. 
We grow what may here be divided into two classes of plants. 
The one class may be called foliage and the other flowering, including 
in the latter those grown for fruit. For the former class we are pretty 
unanimous in giving quantities of manure of the carbonaceous kind 
and much nitrogen. Experience has taught the observant to avoid 
such for flowering and fruiting plants in general ; hence there has 
been a great demand for loam—virgin, brown, or hazel loam—for fruit 
frees and for flowering plants in pots ; and just because of this loam 
not being always forthcoming, or because of the injudicious enriching 
of it, not always the best results have been forthcoming. The main 
virtues of virgin loam are owing to the fact that in it is to be found a 
good deal of plant food not of the carbonaceous kind. The fault of 
worn-out—that is, too heavily manured loam, is not that it wants 
mineral food, but that it contains too much carbonaceous ; not that 
it is deficient in all the elements calculated to produce growth of the 
most fertile kind, but in addition that which so dilutes it as to run it 
out ; not into fruit and flowers, but into carbonaceous leafiness—un 
fruitful luxuriance. 
We are not aware of the theory being before submitted by any 
other writer, but we are certainly of opinion that too much organic- 
matter in the form of carbonic dioxide or of nitrogen is against the 
production of wood of a floriferous or fruitful character, because it 
encourages a growth that is not solid enough, contains not mineral 
enough, but is watery, carbonaceous, lax, and contains only enough 
to support itself or growth of similar character. Flowers attract 
matter from the body of plants to form fruit, and in that is stored 
the essence of plant-growth. Seeds are the magazines of future 
existence ; but growth grown lax by reason of highly nitrogenous food, 
or carbonaceous because of the gas absorbed too largely by leaf or 
by root, has not this essence to spare—all it finds is spent on itself. 
Yet at certain periods fruit-bearing plants demand much* carbon. 
This is always the case when heavy crops are swelling or maturing. 
Is not this the time to give carbon ? Not in the air. This is not 
only impracticable, but would be attended with danger to animal life, 
but by the root. Decaying manure yields carbonic dioxide largely, 
water dissolves its own bulk of it. A thick coat of such over a vinery 
border at certain seasons, through which the necessary" w T ater was 
passed, would not fail to convey abundance of carbon to the plants 
just when the plants demanded it, and y r et enable us to keep our loams 
in that hazelly state which alone secures lengthened fertility, because 
it does not over supply carbon when not wanted, and therefore enables 
the cultivator to secure a real maturity of wood in room of that undue 
extension of cells which, while it furthers enlargement, prevents 
storage. 
To the farmer such questions as these are only" of secondary im¬ 
portance ; hence nothing has been done by agricultural experimenters 
in this direction. To gardeners they are of the first, if they are ever 
to advance and be sure of the road along which advancement is made. 
If science were to clear up such questions as these gardening advance 
would not be merely personal and isolated—would not die with the 
individual and ever slip half steps backward, but move forward in 
general, and the advance of every individual be the advancement of 
tlie whole, because every" advance would be understood. Such work 
w r ould ennoble the doings of the R.H.S. ; but Society work, like 
Government w r ork, though often useful, seldom advances either science 
or practice. 
To what extent nitrogen is derived from the air is an unsolved 
problem. We know how much ammonia is washed into the soil ; w r e 
have reason to believe that the soil absorbs some more of itself, and 
that it is separated by the leaves from air, but to what extent we 
know not. The amount of ammonia and nitric acid in the air is very 
small, but because of its diffusibility it is always in contact with the 
leaves of plants. Hence we are inclined to think that more is sepa¬ 
rated than is generally believed. Ville’s theory that some plants— 
the Leguminosse—have the power of using the free nitrogen of the 
air is not supported by scientific evidence. His experiments and 
those of his supporters were too loosely conducted to prove anything. 
Certain it is that nitrogen must be applied to the soil. Possibly" 
good might follow its use in the air. These points all require inves¬ 
tigation, and will probably be placed on a proper footing one day. 
—Single-handed. 
NATIONAL APPLE CONGRESS, 1883. 
The following circular has been issued on this important subject, 
and w-e would ask the co-operation of all Apple cultivators towards 
rendering the collection as complete and as widely representative as 
possible. We would also recommend that those .having Apples which 
they desire to have named, should send them to this Congress for 
that purpose, with stamped directed envelopes for replies in each case 
accompanying the fruit. Through no other source can the names be 
supplied with equal authority. 
“ At a meeting of fruit-growers, held at South Kensington in 
conjunction with the Fruit Committee of the Royal Horticultural 
Society on the 11th September, it was decided to hold a conference 
on Apples, in the great conservatory of the Society at Chiswick, from 
the 4th to the 18th October next. 
“ The unusually abundant crop of this year affords a favourable 
opportunity for examining the numerous varieties cultivated through¬ 
out the country, to correct their nomenclature, and to compare their 
merits. For this purpose the Council of the Royal Horticultural 
Society have given the use of their great conservatory, and the col¬ 
lection of Apples grown in the garden, which contains many typical 
varieties, will be available for comparison. 
“ This Conference will not take the form of an ordinary exhibition, 
as there will be no competition and no prizes, the sole object being 
to seize so favourable an opportunity of gaining information, and 
making the meeting instructive and educational. 
“ All fruit-growers are invited to send, and the more widely the 
collections are procured the greater will be the interest the Exhibition 
will create. It is very desirable, therefore, that every collection should 
be accompanied with as much information as can be furnished with 
