315 



author also imagines " that all things exist according to a suitable ar- 

 rangement, the laws or conditions of which may, in some measure, be 

 ascertained by a well-directed investigation," the first requisite for 

 which is such an acquaintance with the various objects as will enable 

 the enquirer " to recognise and identify them wherever they appear." 

 This knowledge can be gained only "by studying the features of each 

 individual," and can be applied only by the several individuals being 

 characterised, so that each may be distinguished from all others of its 

 class. This may be termed " the process of separation or disjunc- 

 tion ; and an object thus discriminated is termed a species.^'' 



The author then briefly treats of " the process of combination^'' by 

 which species are formed into genera, these again into other groups, 

 and so on, until all the objects in any kingdom of nature are classed 

 under a few grand divisions. These groups, being but interrupted 

 links, " where nature probably exhibits a continuous chain," must be 

 to a certain extent artificial, a separation into species or individuals 

 being the only real classification indicated in nature. The author 

 meets the objection that naturalists "waste their time and energies 

 upon the external character and appearance of objects, instead of ap- 

 plying themselves to ascertain their relationship, properties and uses," 

 — by remarking that the former is an indispensable preliminaiy to the 

 successful prosecution of a higher course of research, to the pro- 

 motion of which a still farther advance must be made, " namely, to 

 ascertain the range or distribution of species, with their relative con- 

 dition, and other attendant circumstances in any different region of 

 the globe." 



" Now, in prosecuting such an investigation, I consider it necessary to commence 

 by mapping out, or dividing the surface of the globe into appropriate sections ; then 

 to ascertain the various productions which occur in each, with the circumstances at- 

 tending them ; and lastly, to register the information thus acquired, in such a way as 

 to afford a ready and comprehensive view of these productions, both as they exist in 

 any one section, and as they stand relatively to those of other sections." — p. 41. 



In forming these sections, although no abrupt or decided change 

 in their productions may be occasioned by topographical influences, 

 yet may certain lines be traced whereby such changes are indicated ; 

 such lines would form appropriate boundaries for the sections. Thus 

 the ridge of a moimtain chain, a table-land, or the channel of a great 

 river, may sometimes be properly chosen as a sectional line, especially 

 when the former regulate the water-sheds or sources of streams flow- 

 ing in opposite directions. The sections should be so limited in ex- 

 tent that all the important changes occurring in the productions of a 



