80 THREE KINGDOMS. 



It is a great advantage if the study of minerals can 

 be preceded or accompanied by at least a little work 

 in chemistry; and some knowledge of zoology and botany 

 is indispensable to good work in palaeontology, or the 

 study of fossils; while other branches of geology make 

 large demands upon physics, mechanics, etc. In short, 

 a competent geologist, in the broadest sense, must be a 

 cultured person in the whole field of natural scieuce. 



The golden rule in natural science is to study natural 

 objects rather than books; and it is especially important 

 that this rule should be -observed in the study of minerals 

 and rocks. The most perfect descriptions and pictures 

 cannot take the place of the actual specimens or ex- 

 amples, but all knowledge of any real or permanent value 

 must be obtained first hand, i. e., must be based upon 

 personal observation. Books are, of course, useful for 

 reference and to supplement real learning or observation; 

 but the student should regard them merely as auxiliary, 

 and never make them his main reliance. 



When we must resort to books, it is, of course, im- 

 portant to have the best; and the list of works relating 

 to the different departments of geology, which may be 

 found on another page, will aid students in making 

 a wise selection. 



Since the student's main reliance should be upon 

 nature, and not upon books, the collection of speci- 

 mens becomes in most cases a very important prelimi- 

 nary to good work in geology. And students and chap- 

 ters are requested to bear in mind Professor Agassiz's 

 excellent advice to the effect that the most valuable 

 work a society can do, is to make a complete collection 

 and thorough study of the specimens found near its 

 own home. Do not let visions of sparkling crystals 

 or gleaming ores from distant States blind you to the 



