EXT 



EXT 



though it promotes the extraction of the 

 oil, gives it an ungrateful flavour The 

 oils expressed from aromatic substances 

 generally carry with them a portion of 

 their essential oil. Hence the smell and 

 flavour of the expressed oils of nutmegs 

 and mace. 



EXPRESSION, in rhetoric, the elocution, 

 diction, or choice of words in a discourse. 

 Beautiful expression is the natural and 

 true light of our thoughts: it is to this 

 we owe all the excellencies in discourse, 

 which gives a kind of vocal life and spirit. 

 As the principal end of discourse is to be 

 understood, the first thing we should 

 endeavour to obtain is a richness of ex- 

 pression, or habit of speaking so well, as 

 to make our thoughts easily understood. 



EXPRESSION, in painting, a natural and 

 lively representation of the subject, or 

 of the several objects intended to be 

 shewn. The expression consists chiefly 

 in representing the human body, and all 

 its parts, in the action suitable to it : in 

 exhibiting in the face the several passions 

 proper to the figures, and observing the 

 motions they impress on the external 

 parts. See PAINTING. 



EXSICCATION, in pharmacy, the dry- 

 ing of moist bodies, for which two me- 

 thods are usually employed ; in one the 

 humid 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 separate'd by the second method. 

 Vegetables are usually exsiccated by the 

 natural warmth of the air, but the a'ssist- 

 ance 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, or perhaps de- 

 stroyed, by the more slow exsiccation in 

 the air. Some plants, particularly those 

 of the acrid kind, lose their virtues 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 called 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 accord- 

 ing to the quantity of which the magni- 



VOL. V- 



tude or bulk of bodies are estimated. Ex- 

 tension, according 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 con- 

 ceived 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 they 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 valuing of lands or tene- 

 ments ; sometimes the act of the sheriiF 

 upon this writ. 



EXTERMINATION, in general, the ex- 

 tirpating or destroy ing something. In alge- 

 bra, surds, fractions, and unknown quanti- 

 ties, are exterminated by rules for reduc- 

 ing equations. Thus to take away the frac- 



o x 



tional form from these equations -=_ ; 



and 



a 1 -}- b 1 



; in both cases we multiply 



the numerator of one fraction by the de- 

 nominator of the other, and the equations 

 become a y = b x and a*y-\-b-y = 2 c x : 

 so again, to take away the sign of the 

 square, or cube, or other root, as^/a 1 -^ 1 

 = 4r, we raise the 4 z to the second'pow- 

 er, and take off the sign of the root on 

 the other side of the equation thus, a 2 +t/ s 

 = 16 z z : and when n v/ a + b =x-. then 

 a-J-6 = xn. To exterminate a quantity 

 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 a-J-<r= b-\-y 



subtract the upper equation from the un- 

 der and there remains 36 a x=2# b, 



hence 3^=46 a and 4=1 . 



Suppose also two equations given, in- 

 volving two unknown quantities, as 





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 

 O 



