12 National Geographic Magazine. 



present in the light of the past. When thus conceived it forms a 

 fitting complement to geology, which, as defined by the same 

 author, is the study of the past in the light of the present. The 

 studies are inseparable and up to a certain point, their physical 

 aspects may be well followed together, under such a name as 

 physiography. Specialization may then lead the student more to 

 one subject than to the other. 



An illusti-ation from human history, where the study of the 

 past and present has a single name, may serve to make my mean- 

 ing clear in regard to the relation of the two parts of terrestrial 

 history, which have different names. A descriptive and statisti- 

 cal account of a people as at present existing, such as that which 

 our statistical atlas of the last Census gives in outline, corre- 

 sponds to geography in its ordinary limitation. A reasonable ex- 

 tension of such an account, introducing a consideration of antece- 

 dent conditions and events, for the purpose of throwing light on 

 existing relations, represents an expanded conception of geogra- 

 phy. The minute study of the rise and present condition of any 

 single industry would correspond to the monographic account of 

 the development of any simple group of geographic forms. On 

 the other hand, history taken in its more general aspects, includ- 

 ing an inquiry into the causes and processes of the rise and fall of 

 ancient nations, answers to geology ; and an account of some 

 brief past stage of history is the equivalent of paleography, a 

 subject at present very little studied and seemingly destined 

 always to escape sharp determination. It is manifest that 

 geology and geography thus defined are parts of a single great 

 subject, and must not be considered independently. 



History became a science when it outgrew mere nai-ration and 

 seai'ched for the causes of the facts narrated ; when it ceased to 

 accept old narratives as absolute records and judged them by 

 criteria derived from our knowledge of human nature as we see 

 it at present, but modified to accord with past conditions. 



Geology became a science when it adopted geographic methods. 

 The interpretation of the past by means of a study of the present 

 proves to be the only safe method of geologic investigation. 

 Hutton and Lyell may be named as the prominent leaders of this 

 school and if we admit a reasonable modification of their too 

 pronounced uniformitarianism, all modern geologists are their 

 followers. The discovery of the conservation and correlation of 

 energy gives additional support to their thesis by ruling out the 



