168 EMINENT NATURALISTS. 



of refinement in some ancient nation. It lias 

 therefore been found desirable that the antiquary 

 should unite his labours to those of the historian, 

 and similar co-operation has become necessary in 

 geology. The field of inquiry in living nature being 

 inexhaustible, the zoologist and botanist can rarely be 

 induced to sacrifice time in exploring the imperfect 

 remains of lost species of animals and plants, while those 

 still existing afford constant matter of novelty. They 

 must entertain a desire of promoting geology by such 

 investigations, and some knowledge of its objects must 

 guide and direct their studies. According to the differ- 

 ent opportunities, tastes, and talents of individuals, they 

 may employ themselves in collecting particular kinds of 

 minerals, rocks, or organic remains, and these, when well 

 examined and explained, afford data to the geologist, as 

 do coins, medals, and inscriptions to the historian. 



" It was long ere the distinct nature and legitimate 

 objects of geology were fully recognized, and it was 

 at first confounded with many other branches of 

 inquiry, just as the limits of history, poetry, and myth- 

 ology were ill defined in the infancy of civilization." 



After the " Principles ' had passed through five 

 editions, a change was effected in the structure of the 

 work, certain chapters on geology, strictly so called, 

 being separated and reproduced in an amplified form 

 under the title of the " Elements of Geology," whilst 

 the remainder retained its old title.* Much of this may 



* Between 1830 and 1872 eleven editions of this 

 remarkable work were issued, " each so much enriched, 



