170 F. D. ADAMS EXPERIMENT IN GEOLOGY 



geologist now precedes the engineer in all great mining operations where 

 these are efficiently conducted, and could with great advantage to the 

 public purse and public welfare have preceded him in many great civil- 

 engineering enterprises. 



This high attainment in our scientific knowledge of the earth's crust 

 has been achieved by close and long continued observation carried on by 

 many men through many years. 



Observation is the great basis and foundation stone of the science of 

 geology; but as a companion and helper on this delightful, but some- 

 times toilsome, path — and more especially in the later years — observa- 

 tion has had the support of experiment, which while of distinctly subor- 

 dinate and collateral value as compared with observation, has nevertheless 

 rendered many important services in the development of geological 

 knowledge. 



Experiment in geology is in almost all cases really experimentation in 

 physics or chemistry applied to geological problems, and we find at the 

 very outset that here the experimental method is at a disadvantage, in 

 that the scale on which the earth is constructed is so immense, and the 

 forces at work so enormous, and the time concerned so vast, that in many 

 cases the reproduction of the conditions which obtain in nature almost 

 seems beyond our reach. This, however, is by no means always the case, 

 and with the ever increasing facilities at our command experiment is 

 being carried ever farther forward into regions of geological study which 

 in former times seemed to be forever inaccessible to it. 



We are said to experiment when we subject materials to varying con- 

 ditions of pressure, temperature, chemical action, etcetera, and record 

 the changes observed. It is thus possible to ascertain which of these 

 conditions is the essential factor in developing the geological phenomena 

 under observation. 



Furthermore, if it be found that a chemical change or mechanical 

 movement which takes place at the ordinary temperature with extreme 

 slowness is expedited by an increase in temperature, it is often possible 

 by increasing temperature to carry out in a reasonable time an experi- 

 ment which under the exact conditions which obtain in nature might 

 require years, or even decades or centuries, to complete. While, there- 

 fore, many great regions of geological investigation still remain closed to 

 the experimental method, numerous other wide fields of geological study 

 are open to experiment and will probably continue to enlarge as time 

 goes on. 



This was clearly shown when the Governing Board of the Carnegie 

 Institution of Washington had submitted to it the proposal for the estab- 



