282 OPERATIONS SUBSIDIARY TO INDUCTION. 



of little consequence which ; since the second, or as it is usually 

 called, the specific name, could at most express, independently 

 of convention, no more than a very small portion of the con- 

 notation of the term. But by adding to this the name of the 

 superior genus, we may make the best amends we can for the 

 impossibility of so contriving the name as to express all the 

 distinctive characters of the Kind. We make it, at all events, 

 express as many of those characters as are common to the 

 proximate natural group in which the Kind is included. If 

 even those common characters are so numerous or so little 

 familiar as to require a further extension of the same resource, 

 we might, instead of a binary, adopt a ternary nomenclature, 

 employing not only the name of the genus, but that of the 

 next natural group in order of generality above the genus, 

 commonly called the Family. This was done in the mineralo- 

 gical nomenclature proposed by Professor Mohs. " The names 

 framed by him were not composed of two, but of three ele- 

 ments, designating respectively the Species, the Genus, and 

 the Order ; thus he has such species as Rhomboliedral Lime 

 Haloide, Octahedral Fluor Haloide, Prismatic Hal Baryte" * 

 The binary construction, however, has been found sufficient in 

 botany and zoology, the only sciences in which this general 

 principle has hitherto been successfully adopted in the con- 

 struction of a nomenclature. 



Besides the advantage which this principle of nomenclature 

 possesses, in giving to the names of species the greatest quantity 

 of independent significance which the circumstances of the case 

 admit of, it answers the further end of immensely economizing 

 the use of names, and preventing an otherwise intolerable 

 burden on the memory. When the names of species become 

 extremely numerous, some artifice (as Dr. Whewellf observes) 

 becomes absolutely necessary to make it possible to recollect 

 or apply them. " The known species of plants, for example, 

 were ten thousand in the time of Linnaeus, and are now pro- 

 bably sixty thousand. It would be useless to endeavour to 

 frame and employ separate names for each of these species. 



* Nov. Org. Renov. p. 274. t Hist. Sc. Id. i. 133. 



