30 IOWA ACADEMY OF SCIENCES. 



the truth was actually known. When, however, the meth- 

 ods of the new physics were adopted and the new appli- 

 ances came into use, then the wonderful plan and vastness 

 of material creation began to unfold itself to man. The 

 alliance between astronomy and physics has grown closer, 

 and striking and brilliant discoveries have resulted from 

 it. Out of the physical laboratory have come the instru- 

 mental aids by which the astronomer reaches out into the 

 confines of the infinite heavens. 



Another study of physical laws and the results of their 

 action on a grand scale and in almost hopeless intricacy 

 and complication, is the physics of the earth, as geology 

 now ha.s come to be named. Eminently a science of very 

 patient "and discriminating observation, comparisons and 

 classification, it was at a late day in the eighteenth cen- 

 tury that it assumed a place as a respectable science. 

 Geology draws with great freedom upon all other sciences 

 for its aid. Physical laboratory methods find no great 

 application, but familiarity with the principles and laws 

 of physics are so much the more necessary here. The 

 great length of time required for the processes he investi- 

 gates, and the complex character of the evidence presented 

 to him, demands of the geologist not only a clear knowl- 

 edge of all forms of force and energy but an especially 

 critical and discerning mental quality. And to attain or 

 heighten this characteristic he needs thorough training in 

 physics. 



Chemistry is perhaps the nearest of kin to physics, both 

 in respect to subject matter of investigation and in the 

 minute accuracy of its processes. The boundary between 

 their provinces is indefinite, and where physics ends and 

 chemistry begins, it is often impossible to tell. The latter 

 has become the more special and restricted both in methods 

 and in the extent of its field. Chemistry, however, attained 

 to the mental majority of a modern science much later 

 than physics, and did so through the aids furnished by the 

 physicists, and by assimilating their methods and adopting 

 their standards of testing evidence. 



