1902.] DAVIS— SYSTEMATIC GEOGRAPHY. 247 



matter of fact, geography has some time been more deductive than 

 geographers have supposed it to be ; and the newer phase of the 

 science is not characterized so much by introducing deduction for 

 the first time, as by insisting on its whole-souled acceptance as an 

 essential process in geographical research. 



It is only by giving the fullest exercise to the faculties of imagi- 

 nation and deduction that the cycle of erosion becomes serviceable. 

 Here the geographer who hesitates is lost. Not only should the 

 ideal cycle be followed in imagination through all its gradual 

 changes on a large variety of structures, but the special cycles of 

 arid and of frigid climate must be similarly treated ; and then each 

 of these cycles must be broken up by earth-movements into partial 

 cycles and episodes. It is only in this way that the scheme of the 

 cycle gains a serviceable elasticity ; and it is highly significant that 

 among those geographers who find the conception of the cycle un- 

 fruitful is one who has, with more candid indication of his unex- 

 ercised imagination than he may have supposed, likened it to a 

 *' strait jacket." 



Those who have not attained some fluency in the verbal transla- 

 tion.of the various stages of normal and special, simple and inter- 

 rupted cycles can have little understanding of the practical aid that 

 is derived from this method of description. The empirical geog- 

 rapher, unsupplied with a store of carefully imagined and well- 

 defined type forms, sees only what is before him in the field — if 

 indeed he sees so much as that. The geographer who calls the 

 faculties of imagination and deduction to his aid, draws from 

 his mental store one type after another in the effort of matching the 

 explained ideal forms with the actually observed forms. Thus com- 

 paring the partial view of the landscape, as seen by his outer sight, 

 with the complete view of the type as seen by his inner sight, he 

 determines, with great saving of time and effort, just where his next 

 observations should be made in order to decide whether the ideal 

 type he has provisionally selected fully agrees with the actual land- 

 scape before him. When the proper type is thus selected, the ob- 

 served landscape is concisely and effectively named in accordance 

 with it ; and description is thus greatly abbreviated. It goes without 

 saying that this relatively advanced stage of investigation is not to 

 be reached hastily ; that abundant and elaborate description of actual 

 and of type forms in empirical terms, without a trace of explana- 

 tion, should be demanded of the tyro who aspires to become an 



