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parts are exhaled by heat, in the other they 
are imbibed or absorbed by substances, 
whose texture is adapted to the purpose. 
Bodies combined with, or dissolved in a 
fluid, require the first: such as are only 
superficially mixed with it, are separated 
by the second method. Vegetables are 
usually exsiccated by the natural warmth 
of the air, but the assistance of a gentle 
artificial heat is often found very useful. 
By a moderate fire the more tender flowers 
may' be dried in a short time without any 
considerable loss, either of their odour or 
lively colour, which would be injured, br 
perhaps destroyed, by the more slow exsic- 
cation in the air. Some plants, particu- 
larly those of the acrid kind, lose their vir- 
tues by that process. 
EXTENSION, in philosophy, one of the 
common and essential properties of body, 
or that by which it possesses or takes up 
some part of universal space, which is call- 
ed the place of that body. 
Extension is divided, 1. either into 
length only, and then it is called a line ; or, 
2. Into length and breadth, which is called 
a superficies; or, 3. Into length, breadth, 
and depth, which is called a solid; being 
the three dimensions according to the 
quantity of which the magnitude or bulk 
of bodies are estimated. Extension, ac- 
cording to Mr. Locke, is space considered 
between the extremities of matter, which 
fills up its capacity with something solid, 
tangible, and moveable. Space, says that 
philosopher, may be conceived without the 
idea of extension, which belongs to body 
only. 
EXTENSOR, an appellation given to 
several muscles, , from their extending or 
stretching the parts to which thpy belong, 
See Anatomy. 
EXTENT, in law, a writ of execution or 
commission to the sheriff, of one who being 
bound by statute, has forfeited his bond, 
for the valueing of lands or tenements ; 
sometimes the act of the sheriff upon this 
writ. 
EXTERMINATION, in general, the 
extirpating or destroying something. In 
algebra, surds, fractions, and unknown 
quantities are exterminated by the rules 
for reducing equations. Thus to take away 
the fractional form from these equations 
a x a 1 + b 2 x , 
? — - X and — f — = - ; m both cases 
b y tic y 
we multiply the numerator of one fraction 
by the denominator of the other, and the 
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equations become a y = bx and try -f- tfy 
=2c x : so again to take away the sign of 
the square, or cube, or other root, as 
\/ " l ~i“ !/ 2 — iz we ralse the to the 
second power, and take off the sign of the 
root on the other side of the equation thus 
a 2 -f- y 2 — 16z 2 : and when n \/ a -|- b — x ; 
then a + » = *”• To exterminate a quan- 
tity from any equation there are divers 
rules. See Algebra. 
We shall however give an instance in this 
place : thus to exterminate y out of these 
two equations a4-i= b 4- it 
3b = 2x-\-y 
subtract the upper equation from the under 
anti there remains 36 — a — x — 2x — 6, 
hence 3x = 46 — a and 4=1 ' l . 
Suppose also two equations given involv- 
ing two unknown quantities, as 
c a a 
id. a 
ax -{-by — 
x + ey=f\ 
then shall y— 
af — (It: 
ae — dbt 
Where the numerator is the difference of 
the products of the opposite coefficients, 
in the orders in which y is not found ; and 
the denominator is the difference of the 
products of the opposite coefficients, taken 
from the orders that involve the unknown 
quantities. For from the first equation it 
appears that ax — c — by, and a; = 
— ; and from the second equation, 
that <1 x = f 
Therefore, 
dbyz= af 
af — cd; and y 
— eyj and 
by f — . 
. /— ey 
\ d ' 
-ey , , 
— - — 1 ; and c d — 
a • d ’ 
aey, whence aey — dby = 
df — cd 
ae — db' 
To exemplify this theorem, suppose a = 
5, 6 = 7, c = 100, d = 3, e = 8, andy = 
80. Then y = 
5 X 80 
X 100 
5X8 
100 5 
— =5-; and * = 
240 
3X7 
_ 12 
l9~ 12 19 ' 
If three or four equations are given, in- 
volving three or four unknown quantities, 
their values may be found much in the same 
manner. 
EXTERNAL medicines, the same with 
local or topical medicines. 
External angles, are the angles on the 
outside of any right-lined figure, when all 
the sides are severally produced, and they 
are all, taken together, equal to four right 
angles. 
EXTINGUISHMENT, in law, where- 
\ 
