CHARCOAL. 
stituent parts of air, water, and charcoal. The ex- 
periments of Boussingault on the origin of nitro- 
gen in organic bedies show, Ist, that no plant ex- 
ists without a proportion of nitrogen; and 2d, that, 
while men and animals receive the portion of ni- 
trogen of their bodies not from the air by breath- 
ing, but from food by assimilation, plants on the 
contrary draw their supply of nitrogen, not from 
manure or humus, but from the air. We come 
now to avery important point in the nourishment 
of plants, to which M. Payen has particularly call- 
ed our attention in two treatises read before the 
Academy of Sciences at Paris, on the 8th and 
14th of October, 1839: viz., that charcoal oper- 
ates as a condenser, under the influence of water, 
on the constituent parts of the air, in the same 
manner as spongy platina on the elements of de- 
tonating gas; so that nitrogen and oxygen are 
dissolved, and, mixing with water, are absorbed 
by the spongioles, and carried to the cambium 
| for assimilation. This property of condensing 
the air, and making it fit to be received by 
plants, does not exclusively belong to charcoal, 
for it is also more or less perceptible in other 
sorts of earth, chiefly in porous and pulverized 
bodies. We know that water, even when not 
_ distributed through charcoal or earth, absorbs 
some air, which becomes a watery fluid, and by 
heating is again expelled in the form of gas: but 
charcoal-powder appears to possess this power in 
the highest degree; consequently, besides light 
and heat, is capable of carrying to the roots both 
air and water, i.e., nitrogen, hydrogen, and oxy- 
gen, in the greatest abundance. 
“3. Decomposition of the Charcoal, and Forma- 
tion of a nourishing Substance for Plants —It is 
well known that manure, as such, does not nour- 
ish plants, and that, on the contrary, when it 
touches the roots it causes disease. We know 
that it isthe constituent parts of the humus, i.e., 
the matter produced by decay, which nourish 
plants. This apparently takes place because the 
humus, with the co-operation of air and water, 
is continually forming oxide of charcoal, or car- 
bonate and nitrogen, which, together with the 
saline particles, is absorbed and assimilated by 
the roots. Fora long time it was generally be- 
lieved that charcoal, as an inanimate body inca- 
pable of decay, contributed in no degree to the 
nourishment of plants, and that charcoal-dust 
could only serve at most to make the earth looser 
and warmer. But M. Lucas found, from his ex- 
periments, that the charcoal in which plants 
grow by degrees undergoes decomposition, and 
at last becomes a sort of humus. This obviously 
takes place merely because the charcoal dust acts 
| as humus, and, with the co-operation of water 
and air, continually gives out to the plants oxide 
of charcoal, or carbonate, together with the sal- 
ine particles which are in the charcoal, and re- 
main in the ashes after burning. But, to prove 
this, some chemical experiments were necessary. 
“4, Antiseptic Power of Charcoal.—In judging 
CHARLOCK. 
(71 
of the effects of charcoal on vegetation, its anti- 
septic properties are of great importance, for it | 
has very little power of retaining water, and the 
little it retains is partly absorbed by the roots | 
and partly evaporated. ‘This property deserves 
the greatest attention of gardeners, in respect to 
recovering the health of plants the roots of which 
have become injured by being in a clayey soil, 
and too freely watered, or after continued rain, 
or being in contact with manure not sufficiently | 
decomposed. They should be immediately trans- 
planted into charcoal powder, as the most effec- 
tual method of cure.” i 
Liebig, though not offering any lengthened 
explanation, but speaking as if the point were 
more a matter of long-established notoriety, than 
of recent experiment and theory, gives his pow- 
erful testimony in the same direction as Buch- 
ner, and says, “Charcoal, in a state of powder, 
must be considered as a very powerful means of 
promoting the growth of plants on heavy soils, 
and particularly on such as consist of argillace- 
ous earth.” Two sets of interesting and success- 
ful experiments were recently made upon the 
growing of turnips with charcoal manure,—the 
one with common wood charcoal, by the Earl of 
Hssex,—the other with peat charcoal by W. Up- 
pleby; and both are recorded in the volume of 
the Royal Agricultural Society’s Journal for 
1845.—Philosophical Magazine, vol. iii Annales 
de Chimie, vols. Xxxi, xxxii, xxxvi, xlii—Wichol- | 
son’s Journal, vol. iv.—Loudon’s Gardener's Mag- | 
azine, Vols. xvii. and xix.—Journal of the Royal 
Agricultural Society, vol. v.—Marshall’s County 
Reports.—Inebig’s Chemistry of Agriculture. 
CHARGH. A thick adhesive plaster, applied 
warm to a weak or diseased part of a cow ora 
horse, and taking so firm a hold of the hair and 
the skin as to remain for a very long time closely 
attached. Charges are far less frequently used | 
in modern than in former veterinary practice; 
yet, in the case of several kinds of weakness and 
disease, they might still, with eminent advantage, 
be uniformly employed. In any case, a charge 
may protect from cold, and serve as a bandage; 
in rheumatism, it not only protects from cold, | 
and supports the limb, but gently stimulates with 
its resin; and in windgalls, old lamenesses, and 
other complaints which require to be blistered or 
fired, it follows up the action of the chief remedy 
by serving as a continued bandage. A mixture 
of resin or burgundy pitch with wax or oil serves 
for any ordinary charge, but ought to be applied 
in a half-melted condition, and covered with 
flocks or short tow as it cools; and, when a lo- 
cally strengthening influence is desired, arme- 
nian bole, litharge, crocus metallorum, or any 
similar substance may be added. 
CHARLES’ SCHPTRE. See Prepicunaris. 
CHARLOCK. Several yellow-flowered weeds, 
which infest corn-fields, and belong to the cru- 
ciferous tribe of plants. The chief is the corn 
charlock mustard, Stnapis arvensis. This is an 
ou Peay z e ; ’ 
