GEOLOGY AS PART OF A COLLEGE CURRICULUM. 45 



aids to the normal faculties of observation. A couple of 

 hammers, a pocket lens, a chisel and a few pointed steel 

 tools for revealing fossils, a tape line, compass and clinometer 

 are the few equipments that will enable the geologist to carry 

 his investigations to almost any degree of thoro-ughness. 



What has already been said applies to the study of the pure 

 science of geology either in the field or in the laboratory. There 

 is still another use to which this, as other sciences, may be put 

 in disciplining the college student in directions not provided 

 for by literary or mathematical studies, — the study of man as an 

 investigator. In the pursuit of the study of geology, the first 

 instruction must be received in didactic form, but after the text- 

 book and lecture stage is passed, or while it is under way con- 

 sultation of the literature of the sciences is appropriate. In the 

 use of scientific literature the critical judgment is brought under 

 training, and the varying interpretations of well known phe- 

 nomena by expert scientists suggest the prominent part which 

 the notions already in the mind play in the interpretation of the 

 external facts observed. The experienced geologist will recall 

 many cases of honest report of impossible facts by men who are 

 unable to distinguish between what they saw and the false inter- 

 pretations they made of these observations. One man will 

 report that a live toad jumped out of the middle of a solid 

 piece of coal, when it was heated in the stove ; another will 

 swear that he saw a fossil shark's tooth taken out of a ledge 

 of Trenton limestone. It is evident that our memory of 

 observation is not the revival of the object producing the 

 sensation, but of the idea we framed of the sensation at the time. 

 The study of original descriptions of objects of nature reveals 

 the fact that the describer uses the ideas he already has in his 

 mind as he does the standard foot-rule in his hand for measur- 

 ing that which he describes, and it is by the study of scientific 

 literature and the comparison of views of many scientists that 

 this highest discipline of the observational faculties is attained — 

 the power to determine the personal equation of error for the 

 observer, and thus see through his descriptions a truer represen- 



