THE PROBLEMS OF GEOLOGY 543 



to order under the principles of physics and chemistry, the plan was 

 followed of oscillating between observations of the facts as exhibited 

 in the field and laboratory, and their physical-chemical explanation. 

 After a large number of facts were observed in the light of known 

 principles, the attempt was made better to formulate the principles 

 which explain them. After this was done, the facts were again more 

 comprehensively studied in the field and in the laboratory in the light 

 of the new principles. The statement of principles was then modified 

 and improved by use of the new facts. The improved statement of 

 principles was again tested by further facts. Thus the process of 

 development has been a series of approximations toward both com- 

 pleteness of statement of fact and perfection of formulation of prin- 

 ciple, but neither has been attained, nor, so far as we can see, will 

 they ever be reached. 



Necessity for Advance in the Sciences of Physics and Chemistry 



Very often, in the attempt to find principles applicable to the 

 phenomena of deformation and metamorphism, it has been found 

 that the science of physics-chemistry is not sufficiently advanced to 

 make this possible. In such cases physicists and chemists have been 

 asked to develop this subject at the needed points. But at innumer- 

 able places the problems have proved to be so numerous and complex 

 that the necessary aid has not been obtainable. Thus there has 

 arisen, with reference to my own work, a great line of unsolved 

 problems which demand the cooperation of physicists and chemists. 

 The same is true of the work of all other geologists interested in the 

 fundamental problems of geology. As a consequence, when a com- 

 mittee was appointed by the Carnegie Institution to consider what 

 could best be done for the advancement of geology, it was unani- 

 mously decided that the most pressing need of the science was, not 

 further support of the study of the phenomena of geology, but the 

 advancement of the principles of physics and chemistry upon which 

 geology is based. 1 In a small way some of the physical and chemical 

 problems, the solution of which are asked by geologists, have been 

 taken up by the Carnegie Institution. Thus the demands of the 

 geologists that their science shall be reduced to order under the 

 principles of physics and chemistry are likely to result in important 

 advances of these sciences. 



Defects of Geological Literature 



If further proof than that already given were needed of the import- 

 ance of the knowledge by geologists of the basal principles of the 

 1 Carnegie Institution Y ear-Book, no. 1, 1902, no. 2. 1903. 



