|| was introduced to Britain in 1779. 
CHAMPACA. 
strong infusion, taken warm, and in a large quan- 
tity, provokes vomiting ; in consequence of which 
it is used in this manner in order to assist the 
action of emetics. It is also administered with 
advantage as an anthelmintic. The pulverized 
flowers are an excellent mild tonic to both horses 
| and cattle; and are peculiarly suitable either 
during. the presence of low fever, or in other 
cases in which stronger tonics might have too 
powerful an action.— Wild chamomile, Matricaria 
chamomilia, is @ very common, annual, white- 
flowered, pinnate and linear leaved weed of the 
| road sides, waste grounds, and freshly turned 
spots of Britain. It was formerly of great repute 
| as a remedy for uterine diseases; and after hav- 
ing gone almost quite out of use, it has recently 
come again into great request in connexion with 
homeceopathy. 
CHAMPACA,—botanically Michelia champaca. 
| A beautiful, tropical, evergreen timber-tree, of 
the magnolia tribe. It is a native of India, and 
Its stem 
usually grows to the height of about 20 feet. Its 
timber is employed by the Hindoos in making 
drums. The pulverized bark of its root is used 
to excite the flow of the menses. Its flower has 
a golden colour, eminent beauty, and so power- 
| ful an odour that bees will not alight upon it; 
and it is held in high estimation by the Hindoos, 
and dedicated to Krishna. 
CHANGE OF CROPS. See Rorarron. 
CHANGE OF SEED. See Sznp. 
CHARD. See Bert and Carpoon. 
CHARCOAL. A well-known black substance, 
which possesses many singular chemical proper- 
_ ties, the details of which are given under the ar- 
_ ticle Carson. In the present article we shall 
| confine ourselves to the modes of preparation 
_ employed in Britain and in Ene, and to its 
economical uses. 
| Charcoal which is employed as fuel, is Petained 
|| generally from wood of different kinds; the most 
|| dense and hard being preferred. The white and 
resinous woods are commonly rejected. Large 
timber is seldom employed for this:purpose, both 
| because it is too expensive, and because it does 
| not yield charcoal equal in quality to that pro- 
cured from coppice wood. Pieces of three or four 
inches thick must be cloven into four pieces. It 
is an object of some moment to ascertain the 
most productive wood in the preparation of char- 
coal; and ‘although accurate results are not to 
be expected on the great scale, yet experiments 
made by Mr. Mushet afford very good general 
| proportions, which may be the rule by which the 
products may be estimated. 
The following table exhibits very satisfactorily 
the results of these experiments. 
100 parts of Colour. 
Lignum vite afforded 26°8 charcoal, greyish. 
Mahogany - - 25°4 — brown. 
Laburnum - - 24°55 — _ velvet black. 
Chestnut - - 23°22 —~_ glossy black. 
CHARCOAL. 
Oak - 2 22°6 charcoal, black. 
American Wind beech: fine black. 
Holly = a 19-9 = dull black. 
Sycamore - - LO (ee tien blacks 
Walnut < = 20°6 pe dull black. 
Beech S = 19:9 al dull black. 
American maple LO) Os Cullg lac ke 
Norway pine - 19:2. — ‘shining black. 
lime = = 19°5 pa fine black. 
Sallow a s 18:4 a velvet black. 
Ash - © - iO =e ashinineablacks, 
Birch - S 17:4 ie velvet black. 
Scottish pine - 16-4 — _ brownish. 
In Scotland very large quantities of charcoal 
are prepared for the iron works, in the following 
way :—A platform, having a diameter of from 
twenty to thirty feet, is formed on the ground, 
by laying strata of earth upon it, and giving it a 
slightly convex surface. On the centre of this 
circular area, a circle of sticks are so placed as to 
cross each other a little below the top, and thus 
to form a cavity resembling an inverted cone, 
around which successive concentric layers of 
truncheons, having a diameter of from one to ten 
inches, are placed; care being taken, that the 
truncheons in the same circle are of the same 
size, and as few interstices as possible left. The 
exterior circle is composed entirely of brushwood. 
When the platform is nearly covered, a coating 
of turf is laid on the pile, the grassy side being 
next to the wood; dry earth is then heaped up 
around the lower part, and well rammed down, 
so as to exclude all air. The pile is then lighted, 
by placing a few inflamed chips of wood in the | 
interior cavity; and when these are consumed, 
others are added during the first three or four 
days. When the upper part of the pile is com- 
pletely inflamed, a row of holes, each of which 
has a diameter of two inches, is made around it 
at a few inches below the top, and the opening 
at that part is closed up. The flame then gra- 
dually descends to the circle of holes, and its ar- 
rival there is announced by a very perceptible 
diminution of smoke and vapour. Another row 
of air holes is then made at a distance of six or 
eight inches below the first row, which are closed 
up; and the same operation is repeated until the 
flame has been conducted to the lowest part of 
the pile, which generally happens in about a fort- 
night; when the whole is carefully covered until 
the fire is extinguished. Such pieces as are not 
completely charred, are separated, and reserved 
as fuel for the next pile. The charcoal produced 
from the truncheons is laid aside for particular 
uses; and that obtained from the brushwood is 
sold, under the name of small coal, as fuel. 
In France there is some difference in the mode 
of preparing the charcoal: it therefore is worth 
while to give an outline of the various processes 
there adopted. The wood is cut down in large 
faggots, and after having been well dried for some 
months, it 1s divided into brushwood, small and 
large faggots. The last are cut into truncheons 
of three or four feet in length. The turf is then 
taken off a square or circular space, having a 
