JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
520 
[ December 7, 1882. 
care. They are both sturdy growers and good bearers on the wall 
in different aspects. They are not over-particular as to soil or 
situation, but should have liberal treatment. Coe’s Late Red 
and Ickworth Impdratiice are first-rate for tarts and preserving, 
hanging on the trees well into November, and are highly esteemed. 
They must, of course, be protected from birds, and as far as 
possible from drenching rains, so frequent at this season.— 
Prunus. 
Lane’s Prince Albert Apple. — I observe that one of your 
correspondents asks for details respecting this Apple. My ex¬ 
perience of it has been most favourable ; indeed I have more than 
once told Mr. Lane, sen., that he ought to make more of this 
Apple, as the more it is known the better it is liked. It is curious 
that in another column of the same issue (November 23rd) this 
Apple is mentioned as having proved a great success at Mentmore. 
By the kindness of Messrs. Lane I have been furnished with an 
account of their Prince Albert, from which I have extracted some 
details. This variety was obtained from a seedling tree in the 
garden of Mr. Squire of Berkhampsted, and was sent out by 
Messrs. Lane a few years since. It has been in great demand 
during the past season, as those who have tried the tree are plant¬ 
ing it in larger numbers. It is a culinary Apple, lasting until 
March. The fruit is somewhat large, of a greenish colour, with 
a tinge or flush of red on the side next the sun ; the flesh is white. 
The tree is hardy and succeeds in almost any soil, but it fruits 
best as a pyramid, though it does well as a standard. It rarely, if 
ever, fails to produce a crop. Unlike many varieties that require 
to be grown on the Paradise stock for early fruiting, Prince 
Albert is described as producing fruit the second year after 
grafting when grown on the free stock. Those w’ho wish to 
obtain this variety should plant pyramids as the best form of 
cultivation for this Apple.—E. Bartrum, Berkhampsted, Herts. 
In answer to “A Sussex Amateur” respecting Lane’s Prince 
Albert Apple, I can very strongly recommend it as a most ex¬ 
cellent kitchen Apple, one that with me never fails to give a 
crop, lily soil is in first-rate condition, as I never spare manure, 
and periodically trench or dig the ground two spits deep, burying 
the manure at the bottom of the trench, so that I have always 
plenty of soil for my trees to grow in and feed on. I have not 
tested the keeping properties of the Apple, as it has always been 
a favourite for the mincemeat, and it is then perfectly sound, 
but I have no doubt would keep to the end of January. I find it 
a very free grower, having some seasons to shorten the shoots 
back 2 feet.— George B. Clarke, Woburn. 
OF HUMUS. 
(Continued from page 408.) 
As many soils contain very little humus, and the most barren 
soils often contain it in abundance, it cannot be said, as was 
formerly erroneously supposed, that the proportion of humus 
present affords a sure index by which we can judge of their fer¬ 
tility. With the more correct information we now possess on the 
part played by humus in vegetation, it can be asserted only that 
fertile soils are usually characterised by its presence in consider¬ 
able quantities, though such presence may be sometimes injurious; 
and Liebig appears to me to have spoken unadvisedly when, in 
his “ Familiar Letters,” he wrote that it is without action if the 
fixed mineral constituents serviceable to plants are absent from 
it.” On the contrary, it will appear from other numerous and 
well-weighed statements of his, that the presence of humus, quite 
independently of any mineral substances it might possess, has a 
most important influence in increasing and maintaining fertility. 
For one proof of this I have only to refer to my last letter, in 
which the absorptive properties of humus for vapour of water (1) 
are dwelt upon. And this valuable function of absorbing water 
is an indication that humus possesses other and, as Ville main¬ 
tains, more useful properties—“It fixes ammonia in the soil, so 
as to prevent its being carried off by rains.” 
Ammonia may exist in the soil in three conditions— (a), as 
gaseous carbonate of ammonia ; ( b ), as ammonia physically con¬ 
densed on the surface of the particles of soil, as happens when 
charcoal is exposed to this gas—a property apparently dependant 
on its porosity ; (c), as ammonia chemically combined, which 
takes place whenever it comes in contact with the acids formed 
during the decomposition of animal or vegetable substances. 
The experiments of Boussingault and Lewy have shown that in 
most cases the gaseous ammonia existing in the soil is minute in 
quantity, and it would appear from their investigations that the 
physically and chemically combined ammonia also (b and c) is 
present in the generality of soils in small amount; but still these 
three causes of storage in fertile soils must exercise an important 
influence, and Liebig concludes that “ soils which contain much 
vegetable matter absorb more ammonia and retain it more firmly 
than soils which are poor in decaying vegetable matter ”—in 
other word-’, as they contain a greater or less per-centage of 
humus. 
It may be remarked here that the degree of decay which the 
inorganic matter of a soil has undergone must materially influence 
the question whether the ammonia which is stored by a soil is 
physically absorbed or chemically combined. As the condition of 
pure humus is more nearly attained, so the quantity of ammonia 
absoibed ( b) will be greater ; whereas, during decay and the for¬ 
mation of the acids of the humus group, the quantity of ammonia 
combined chemically (c) may be the more important. The com¬ 
position of humus is very complex in its chemical character, and 
the knowledge possessed of it is confessedly incomplete. Even 
the results of the analyses of many of the bodies which are sup¬ 
posed to be generated as the decay of humus proceeds, such as 
ulmin and ulmic acid, humin and humic acid, are not in all cases 
accordant. “Either several distinct substances have been con¬ 
founded under each of the above names, or the true ulmin and 
humin and ulmic and humic acids are liable to occur mixed with 
other matters from which they cannot be or have not been sepa¬ 
rated.”—(“7/u?y Crops Feed," S. W. Johnson.) Berzelius dis¬ 
covered that there were two other acids existing in the acid liquid 
from which ulmic or humic acid has been separated, and these 
bear the names of apocrenic acid and crenic acid respectively. 
Mulder remarks that “in every fertile soil these acids (apocrenic 
and crenic) always occur together in not inconsiderable quanti¬ 
ties. When the earth is turned over by the plough two essentially 
different processes follow each other—oxydation, where the air 
has free access : reduction, where its access is more or less limited 
by the adhesion of the particles, and especially by moisture. In 
the loose dry earth apocrenic acid is formed ; in the firm moist 
soil, and in every soil after rain, crenic acid is produced, so 
that the action or effect of these substances are alternately 
manifested.” 
While the precise constitution of all these substances may be a 
matter of doubt therefore—and may remain so while the difficul¬ 
ties of procuring them in a pure state are unconquered—their 
existence in the soil, their production by humus, and “ their 
importance in agricultural science are beyond question.” If, also, 
it cannot be said to be proved that humus is absorbed by plants, 
the evidence in the matter is in the favour of its nutritive func¬ 
tions. “ While no one denies or doubts that the last products of 
the destruction of organic matter—viz., the carbonic acid, am¬ 
monia, nitric acid, and water, together with the ingredients of 
ashes, chiefly nourish agricultural plants, no one can deny that 
other bodies may and do take part in the process.” But although 
crops on the farm are rarely raised without the concurrence of 
humus, or at least without its presence in the soil, it is by no 
means indispensable, as I have already observed, to their life or 
full development. 
In the decay of vegetable matters buried in the soil many other 
acids than those above named are produced ; but as many of these 
can exist only temporarily as the results of fermentation and 
decay, and for the most part pass into carbonic acid, we now turn 
to the influence of carbonic acid in the soil. “Up to the present,” 
Ville says, continuing his remarks upon humus, “ these functions 
have not appeared very important, but now the utility begins to 
be evident. It absorbs the oxygen of the air, and afterwards 
undergoes a slow, inappreciable, but real combustion. It thus 
becomes a source of a gradual but uninterrupted formation in the 
soil of carbonic dioxide, which is less useful on account of the 
carbon it furnishes to vegetation than for the solvent power 
which it exercises with regard to certain minerals, and especially 
calcic phosphate and limestone.” “We shall prove the truth of 
this fact by a very simple experiment. Grow two plants in cal¬ 
cined sand, one with the aid of humus and the other without, 
giving to both the same quantity of chemical manure. In both 
cases the yield will be exactly the same, but analysis will show 
that there is more calcic phosphate in the crop obtained by the 
aid of humus than in that grown by the sand alone. Humus, 
therefore, helps to supply the plants with phosphate.” 
“ Humus can in certain cases produce a still more useful effect, 
for in a measure it increases the yield. This happens ivhen the 
humus is associated with calcic carbonate. 
“ To prove this w r e will make four fresh experiments. In the 
first place we will grow some plants in calcined sand, the soil 
being provided with nitrogenous matter, and all the necessary 
mineral matters which must be employed in these conditions with 
the exception of calcic carbonate. If 22 grains of Wheat are 
sown the crop will weigh from 307 to 337 grains. This yield is 
