114 GILBERT 



formulated and advocated by Powell. That plan involved the 

 abolition of the rival organizations, and the creation of separate 

 bureaus for the topographic, geologic, and ethnologic survey of 

 the western part of the United States. It was finally adopted 

 by Congress, except that no provision was made for an inde- 

 pendent topographic corps. 



The first director of the new Geological Survey was Clarence 

 King, the second Major Powell ; and Powell remained in charge 

 from 1881 until 1894, resigning at last when impaired health 

 demanded the husbanding of his energies. This period was 

 one of rapid development of geologic work in the United States, 

 and the administration of the national work was at least an im- 

 portant factor in that development. The field of the national 

 survey was early enlarged so as to include the whole country, 

 and fears were entertained lest a diminution of state work should 

 result; but the state work expanded along with the national, and 

 through measures of cooperation, each strengthened the other. 

 Though official publication was varied and voluminous, it did 

 not fully keep pace with the growth of geologic activity, and 

 the surplus output was so large as to warrant the institution of 

 two geologic journals and an annual volume of geologic trans- 

 actions. 



Turning now to the narrower field of Powell's personal 

 accomplishment in geology, I find that it can be more conveni- 

 ently epitomized if I first recall to your attention the logical 

 subdivision of all scientific work. 



Those who labor for science do three things : They observe 

 the facts of Nature, taking pains to observe them accurately ; 

 they arrange the observed facts in groups, or classify them ; 

 and they discover their relations of cause and effect, or explain 

 them. When the stage of explanation has been reached a new 

 grouping is made, in which the dominant idea is to bring 

 together things which have a common cause. Some workers 

 devote themselves wholly to observation, using the groupsing 

 and explanations that others have furnished. These are many, 

 and their labors are of great importance. Some there are who 

 strive only to explain, without close observation. These are 

 not in touch with Nature, and their explanations for the most 



