TERMINOLOGY AND NOMENCLATURE. 425 



than he at once creates a term to express them whenever conihined.: 

 just as, in his algebraical operations, he substitutes for [a"' + }/') J^, or 



for - -| h -r + &c., the sinprle letter P, Q,, or S; not solely to shorten 



bed 



his symbolical expressions, but to simplify the purely intellectual part 

 of his operations, by enabling the mind to give its exclusive attention 

 to the relation between the (puintity S and the other quantities which 

 enter into the equatibn, without being distracted by thinking unneces- 

 sarily of the parts of which S is itself composed. 



But there is another reason, in addition to that of promoting perspi- 

 cuity, for giving a brief and compact name to each of the more con- 

 siderable results of abstraction which are obtained in the course of our 

 intellectual phenomena. By naming them, we fix our attention upon 

 them ; we keep them more constantly before the mind. The names are 

 remembered, and being remembered, suggest their definition ; while if 

 instead of specific and characteristic names, the meaning had been ex- 

 pressed by putting together a number of other names, that particular 

 combination of words already in common use for other purposes would 

 liave had nothing to make itself remembered by. If we want toren- 

 der a particular combination of ideas permanent in the mind, there is 

 nothing which clenches it like a name specially devoted to express it. 

 If mathematicians had been obliged to speak of " that to which a 

 quantity, in increasing or diminisliing, is always approaching nearer^ 

 so that the difference becomes less than any assignable quantity, but 

 to which it never becomes exactly equal," instead of expressing all 

 this by the simple phrase, " the limit of a quantity," we should probably 

 have long remained without most of the important truths which have 

 been discovered by means of the relation between quantities of various 

 kinds and their limits. If instead of speaking of momentum, it had 

 been necessary to say " the product of the number of units of velocity 

 in the velocity by the number of units of mass in the mass," many of 

 the dynamical truths now apprehended by means of this complex idea, 

 would probably have escaped notice for want of recalling the idea 

 itself with sufficient readiness and familiarity. And on subjects less 

 remote from the toj)ics of popular discussion, whoever wishes to draw 

 attention to some new or unfamiliar distincti(m among things, will find 

 no way so sure as to invent or select suitable names for the express 

 purpose of marking it. 



A volume devoted to explaining what civilization is and is not, does 

 not raise so vivid a conception of it as the single expression, that Civi- 

 lization is a different thing from Cultivation ; the compactness of that 

 brief designation for the contrasted quality being an equivalent for a 

 long discussion. So, if we would imjiress forcibly upon the under- 

 standing and memory the distinction between what a representative 

 government should be and what it (jftcn is, we cannot more effectually 

 do so than by saying that Rej)resentation is not Delegation. Dr. 

 Chalmers, in order to distinguish his scheme of clerical sujierintcnd- 

 ence of a parish from the mere keeping a church open which people 

 might come to or not as they s[)ontaneously chose, called very expres- 

 sively the fi)rmcr the " aggressive" system, the latter the " attractive." 

 When the earlier electricians fi)und that there were two different kuids 

 of electrical excitement, they soon made tlic world familiar with them 

 by giving them the names of positive and negative, vitreous and resinous. 

 3H 



