CLASSIFICATION BY SERIES. 507 



tension 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 tlie 

 next natural group in order of generality above the genus, commonly call- 

 ed the Family. This was done in the mineralogical nomenclature proposed 

 by Professor Mohs. " The names framed by him were not composed of 

 two, but of three elements, designating respectively the Species, the Genus, 

 and the Order; thus he has such species as Mhombohedral Lime Ilaloide^ 

 Octohedral Fluor Haloide, Prismatic Hal Baryte^'^ The binary con- 

 struction, however, has been found sufficient in botany and zoology, the 

 only sciences in which this general principle has hitherto been successfully 

 adopted in the construction of a nomenclature. 



Besides the advantage which this principle of nomenclature possesses, in 

 giving to the names of species the greatest quantity of independent signifi- 

 cance which the circumstances of the case admit of, it answers the further 

 end of immensely economizing the use of names, and preventing an other- 

 wise intolerable burden on the memory. When the names of species be- 

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

 comes absolutely necessa,ry 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 probably sixty thousand. It would be useless to 

 endeavor to frame and employ separate names for each of these species. 

 The division of the objects into a subordinated system of classification en- 

 ables us to introduce a Nomenclature which does not require this enor- 

 mous number of n.imes. Each of the genera has its name, and the species 

 are marked by the addition of some epithet to the name of the genus. In this 

 manner about seventeen hundi-ed generic names, with a moderate number 

 of specific names, were found by Linnaeus sufficient to designate with pre- 

 cision all the species of vegetables known at his time." And though the 

 number of generic names has since greatly increased, it has not increased 

 in any thing like the proportion of the multiplication of known species. 



CHAPTER VIII. 



OF CLASSIFICATIOISr BY SERIES. 



§ 1. Thus far, we have considei'ed the principles of scientific classification 

 SO far only as relates to the formation of natural groups ; and at this point 

 most of those who have attempted a theory of natural arrangement, in- 

 cluding, among the rest. Dr. Whewell, have stopped. There remains, how- 

 ever, anothei', and a not less important portion of the theory, which has 

 not yet, as far as I am aware, been systematically treated of by any writer 

 except M. Comte. This is, the arrangement of the natural groups into a 

 natural series.| 



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



X Dr. Whewell, in his reply (Philosophy of Discovery, p. 270) says that he "stopped short 

 of, or rather passed by, the doctrine of a series of organized beings," because he "thought it 

 bad and narrow philosophy." If he did, it was evidently without understanding this form of 

 the doctrine; for he proceeds to quote a passage from his "History," in which the doctrine 

 he condemns is designated as that of " a mere linear progression in nature, which would place 

 each genus in contact only with the preceding and succeeding ones." Now the series treat- 

 ed of in the text agrees with this linear progression in nothing whatever but in being a pro- 

 gression. 



