278 OPERATIONS SUBSIDIARY TO INDUCTION. 



there should be a name for every variety of elementary 

 sensation or feeling. Combinations of sensations or 

 feelings may always be described, if we have a name 

 for each of the elementary feelings which compose 

 them ; but brevity of description, as well as clearness 

 (which often depends very much upon brevity,) is 

 greatly promoted by giving distinctive names not to 

 the elements alone, but also to all combinations which 

 are of frequent recurrence. On this occasion I can- 

 not do better than quote from Mr. Whewell some of 

 the excellent remarks which he has made on this 

 important branch of our subject. 



" The meaning" (says he*) " of [descriptive] tech- 

 nical terms, can be fixed in the first instance only 

 by convention, and can be made intelligible only by 

 presenting to the senses that which the terms are to 

 signify. The knowledge of a colour by its name can 

 only be taught through the eye. No description can 

 convey to a hearer what we mean by apple -green or 

 French-grey. It might, perhaps, be supposed that, 

 in the first example, the term apple, referring to so 

 familiar an object, sufficiently suggests the colour 

 intended. But it may easily be seen that this is not 

 true; for apples are of many different hues of green, 

 and it is only by a conventional selection that we can 

 appropriate the term to one special shade. When 

 this appropriation is once made, the term refers to the 

 sensation, and not to the parts of the term ; for these 

 enter into the compound merely as a help to the 

 memory, whether the suggestion be a natural con- 

 nexion as in * apple-green,' or a casual one as in 

 1 French grey/ In order to derive due advantage 

 from technical terms of this kind, they must be asso- 



* Philosophy of the Inductive Sciences, i., 464-5. 



