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iirleas into one conception, or complex 
idea. 
Composition, in music, the art of dis- 
posing musical sounds into airs, songs, &c. 
either in one or more parts, to be sung by 
a voice, or played on instruments. 
Composition, in oratory, the coherence 
and order of the parts' of a discourse. 
To composition belong both the artful 
joining of the words, whereof the stile is 
formed, and whereby it is rendered soft and 
smooth, gentle and flowing, full and sonor- 
ous, or the contrary ; and the order, which 
requires things first in nature and dignity, 
to be put before those of inferior considera- 
lion. 
Composition, in painting, consists of 
two pai'ts, invention and disposition ; the 
fii-st whereof is the choice ot the objects 
which are to enter into the composition 
of the subject the painter intends to exe- 
cute, and is either simply historical or alle- 
gorical. The other veiy much contributes 
to the perfection and value of a piece of 
painting. 
Composition, in commerce, a contract 
between an insolvent debtor and his credi- 
tors, whereby the latter accept of a part of 
the debt in compensation for,the whole, and 
give a general acquittance accordingly. 
Composition, in printing, commonly 
termed composing, the arranging of several 
types or letters in the composing-stick, in 
order to form a line ; and of several lines 
ranged in order in the galley, to make a 
page ; and of several pages to make a form. 
Composition of motion, is an assemblage 
of several directions of motion, resulting 
from several powers acting in different, 
though not opposite directions. See Me- 
chanics. 
Composition of proportion, is the com- 
paring tlie sum of the antecedent and con- 
sequent, with tlie consequent in two equal 
ratios ; as, suppose, 4 : 8 :: 3 : 6, they say, by 
composition of proportion, 12 : 8 :: 9 : 6. 
COMPOST, in husbandry and garden- 
ing, several sorts of soils or earthy matter 
mixed together, in order to make a manure 
for assisting the natural earth in the work 
of vegetation, by way of amendment or 
improvement. 
COMPOUND^^omjct’, in botany, a flower 
formed of the union of several fructifica- 
tions, or lesser flowers within a common 
calyx ; each lesser flower being furnished 
with five stamina, distinct at bottom, but 
united by the anthers into a cylinder, 
through which passes a stVle considerably 
VOh. II. 
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longer than the stamina, and crowued by a 
stigma or summit, with two divisions that 
are rolled backwards. These are the essen- 
tial characters of a compound flower. Com- 
pound flowers which make up four classes in 
Tourneforts system, are all reduced to the 
class Syngenesia, which see. See Botany. 
COMPOUND interest. See Interest. 
Compound motion, that affe('ted by the 
concurring action of several different pow- 
ers. Thus, if one power act in the direc- 
tion of, and with a force proportional to the 
end of a parallelogram, and another act in 
the direction of, and with a force propor- 
tional to its side, the compound motion will 
be in the direction of, and proportional to, 
the diagonal of the said parallelogram. 
Compound numbers, tliose which may be 
divided by some other number besides unity 
without leaving any remainder; such are, 
18, 20, &c. the first being measured by the 
numbers 2, 6, or 9 ; and the second by the 
numbers 2, 4, 5, 10. 
COMPRESS, in surgery, a bolster of 
soft linen cloth, folded in several doubles, 
frequently applied to cover a plaster, in 
order not only to preserve the part from 
the external air, but also the better to retain 
the dressings. See Surgery. 
COMPRESSION, the act of pressing or 
squeezing some matter, so as to set its parts 
nearer to each other, and make it possess 
less space. 
Water was, during a veiy long period, 
considered as a fluid perfectly unelastic ; 
that is, unyielding, or incompressible ; and 
this opinion was corroborated by an expe- 
riment of the Academy del Cimento in 
Italy. About a century and a half ago the 
members of that academy endeavoured to 
ascertain whether water was capable of 
being compressed in any degree. For this 
purpose they filled a hollow metallic 
sphere with tliat fluid, and stopped the 
aperture very accurately. This ball then 
was pressed in a proper machine, but 
no contraction could be observed, nor, in- 
deed, was the apparatus capable of mani- 
festing small degrees of compression. Hence 
they concluded that water was not capable 
of compression. This opinion prevailed un- 
til the year 1761, when the ingenious Mr. 
Canton discovered the compressibility of 
water, and of other liquids, wliich he imme- 
diately made known to the Royal Society. 
He took a glass tube, having a ball at one 
end, filled the ball and part of the tube 
with water, which he had deprived pf air as 
much as it was in his power j then placsii 
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