THE RELATIONS OF THE EARTH-SCIENCES IN VIEW OF 

 THEIR PROGRESS IN THE NINETEENTH CENTURY 



BY WILLIAM MORRIS DAVIS 



[William Morris Davis, Sturgis-Hooper Professor of Geology, Harvard University, 

 since 1898. b. Philadelphia, Pennsylvania, February 12, 1850. S.B. Harvard, 

 1869; M.E. ibid. 1870. Assistant, Argentine National Observatory, 1870-73; 

 Assistant in Geology, Harvard, 1876-77; Instructor, ibid. 1878-85; Assistant 

 Professor of Physical Geography, zfod. 1885-90; Professor, ibid. 1890-98. Mem- 

 ber of National Academy of Sciences; American Academy of Arts and Sciences ; 

 American Philosophical Society; Geological Society of America; Association of 

 American Geographers; and numerous foreign scientific societies. Author of 

 Elementary Meteorology; Physical Geography; and Elementary Physical Geo- 

 graphy; and numerous articles on geology and geography. Associate editor of 

 Science, The American Naturalist, and The American Journal of Science.] 



' FACTS of earth-science have now been so abundantly acquired 

 and so thoroughly systematized that there is some danger of our 

 substituting the schemes in which earth-knowledge has been sum- 

 marized for first-hand knowledge of the earth itself. 



For a fundamental matter like the globular form of the earth, we 

 resort to a hand globe, so admirable in its imitation of nature that 

 we must beware lest the little globe rather than the earth in its 

 true dimensions satisfies our imagination. We have so conveniently 

 divided the geological record of the earth's history into ages and 

 periods that their easily repeated names are apt to replace the 

 laborious conception of long divisions of time. 



Our escape from the danger of taking scheme for fact has lain in 

 the resort to individual observation, and the past century must long 

 be famous for the extent to which advantage has been taken of the 

 opportunity for outdoor study. 



The earth has been explored and measured as never before. The 

 lands have been mapped, the oceans have been charted, by original 

 observers. The air has been followed in its circuits, great and small. 

 The structure of the earth's crust has been patiently traced out. 

 Thus "Go and see " came to be our watchwords one hundred years 

 ago. As long as we, like Antaeus of old, can return to the earth for 

 new stores of the strength that we find in facts, we need not fear 

 being strangled by any voluminous Hercules of theory. 



It is the active appeal to observation that has checked the free- 

 dom of speculation which our brilliant predecessors enjoyed in an 

 earlier century, when their fanciful schemes were little restrained 

 by the barriers of fact that have since then been built up on every 

 side. Indeed, schemes came to be for a time so much in disrepute 

 that some investigators wished to suppress theorizing altogether, as 



