592 



CHARLES R. VAN HISE 



and child — have long existed side by side, and their interaction and 

 mutual effects have been most profound. One cannot be compre- 

 hended independently of the others. 



While geology is very closely related to astronomy and biology, 

 we have seen that it is still more closely related to physics and chemis- 

 try. Since physics-chemistry is the science of energy and substance 

 in general, and since geology is the science of the energy and sub- 

 stance of the earth, geology is not simply related to those subjects — 

 it rests upon them as its one secure foundation. They are the ele- 

 mentary sciences upon which geology is based ; for they are the sciences 

 of all energy and substance of which the object of geological science 

 is an insignificant fraction. 



We have now reached the most fundamental problem of geology — 

 the reduction of the science to order under the principles of physics 

 and chemistry. To a less extent geology is subject to the sciences 

 of astronomy and biology.^ 



While the relations of geology to the other sciences, as above set 

 forth, are incontestible, it was possible to appreciate those relations 

 only after the sciences were well developed. Geology did not begin 

 consciously as the science of the physics and chemistry of the earth. 

 The phenomena of the earth were studied as objects, and thus geology 



I The earth is the vastest aggregate of matter within the direct reach of man. 

 By a study of a small part of this aggregate the principles of physics and chemistry 

 have been formulated. The material which has been studied is but an inappreciable 

 part of the material of the earth, and but an infinitesimal part of the substance of the 

 universe. Yet the doctrine is unhesitatingly accepted that the principles of physics 

 and chemistry, wrought out with reference to this minute fraction of substance, are 

 not only applicable to all the materials of the earth, but to all parts of the visible uni- 

 verse. This daring generalization has received astonishing confirmation by studies 

 of other portions of the visible universe through the spectroscope and photographic 

 plate. 



In the generalization that the principles of physics and chemistry, developed by 

 study of small masses of material, apply to all parts of the universe, we have a case of 

 the extension of a generalization from a part to the whole, which surpasses almost any 

 similar extension of reasoning. Indeed, some philosophers have seriously questioned 

 the legitimacy of the conclusion. 



In view of the foregoing, it is rather curious that the geologist now finds his most 

 important problem, the problem of problems, in the explanation of phenomena exhib- 

 ited by the heterogeneous earth in terms of those principles of physics and chemistry 

 built up mainly by observation, experiment, and reasoning upon a minute fraction of 

 the earth. 



