COM COM 
plants, teiiiiiuale the tlower-stem, and form ivoiy is first sawed into tliin slices, llip 
an appearance like a tnft of hair. best ivory conies from the island of Ceylon 
Coma Berenices, Berenice’s hair, in astro- and Achen, in the East Indies ; as it pos- 
noniy, a constellation of the Northern he- sesses the property of never turning yel- 
inisphere, composed of stars near the Lion’s low, it is consequently much dearer than 
Tail. See Astronomy. any other kind. 
COMARUM, in botany, a genus of the 
Icosandria Poly^gamia class and order. Na- 
tural order of Senticos®. Rosace®, Jus- 
sieu. Essential character : calyx ten cleft , 
petals five, smaller than the calyx ; recep- 
tacle of the seeds ovate, spongy, perma- 
nent. There is but one species ; viz. C. pa- 
lustre, marsh-cinquefoil, a native of most 
parts of Europe, in boggy ground. 
COMB, an instrument made of horn, 
ivory, tortoise-shell, box, or holly-wood, 
&c. and useful for separating and adjusting 
the hair, &c. 
Comb making. Combs are not only 
made for the jir.rpose of cleansing the hair, 
but for ornament : they are sometimes set 
wdth brilliant stones, pearls, and even dia- 
monds ; some again are studded with cut 
steel ; these are of different shapes, and 
are used to fasten up the hair when ladies 
dress without caps. Combs may, of course, 
be had of all prices, from the value of a 
few pence to almost any sum. They are 
generally made of the horns of bullocks or 
of elephants, arid sea-horses teeth, and some 
are made of tortoise-shell and ivory, others 
of box or holly-wood. The horns of bul- 
locks are thus prepared for this manutac- 
tory: the tips are sawn off; they are 
then held in the flame of a wood fire ; this 
is called roasting, by which they become 
nearly as soft as leather. While in that 
state they are slit open on one side, and 
pressed in a machine between two iron 
plates ; they are then plunged into a trough 
of water, from which they come out hard 
and flat ; they are then sawn into lengths, 
according to the size wanted. To cut tlie 
teeth, each piece is fixed into a tool called 
a claw. The maker sits on a triangular 
sort of a stool to his work, and under him 
is placed the claw' that holds the horn, 
ivory, &c. that is to be formed into a comb. 
The teeth are cut with a fine saw', or ra- 
ther a pair of saws, and they aie finished 
with a file. A coarser file, called a rasp, is 
used to reduce the horn, &c. to a proper 
thickness; and when they are completely 
made, they are polished with charcoal and 
water, and receive their last finish w'ith 
powder of rotten stone. The process used 
for making ivory combs is nearly the same 
as that already described, except that the 
Torloise-shell combs are much esteemed; 
and there are methods of staining horn, so 
as to imitate it, of wliich the following is 
one : the horn to be dyed is first to be press- 
ed into a flat form, and then done over with 
a paste, made of two parts of quick-lime 
and one of litharge, brought into a proper 
consistence with soap-ley. This paste must 
be put over all the parts of the horn, ex- 
cept such as are proper to be left transpa- 
rent, to give it a nearer resemblance to tor- 
toise-shell. The horn must remam in this 
state till the paste be quite dry, when it is 
to be brush^ off. It requires taste and 
judgment so to dispose the paste, as to form 
a variety of transparent parts, of different 
magnitudes and figures, to look like nature. 
Some parts should also be semi-transparent, 
which may be effected by mixing whiting 
with a part of the paste. By this means 
spots of a reddish brow'n will be produced, 
so as greatly to increase the beauty of the 
work. Horn thus dyed is manufactured in- 
to combs, and these are frequently sold for 
real tortoise-shell. 
COMBAT, ill law, or single combat, de- 
notes a formal trial between two champions 
of some doubtful cause or quarrel, by the 
sword or batoons. Tliis form of proceeding 
was anciently very frequent, particularly 
among tlie barbarous nations in their original 
settlements; and obtained, not only in 
criminal, but also in civil causes; being built 
on a presumption, that God would never 
grant the victory but to him who had the 
best right. It was originally permitted in 
order to determine points respecting the 
reputation of individuals, but afterwards 
became much more extensive. The accuser 
first sw'ore to the truth of his accusation ; 
the accused gave him the lie : upon which 
each threw down a gage, or pledge of battle, 
and the parties were committed prisoners 
to the day of combat. See Champion. 
COMBINATION, in mathematics, is 
the variation or alteration of any number of 
quantities, letters, sounds, or the like, in 
all tl«i dift'erent manners possible. It 
is shewn, in the Memoirs of the French 
Academy, that two square pieces, each di- 
vided diagonally into two colours, may be 
combined 6-1 different wa3S, so as to form 
so many difterent kinds of chequer- work j 
