MODERN SCIENTIFIC GEOGRAPHY. 7 i 5 



was possible in his day. Scientific geography is dependent upon a 

 number of otber sciences, and its progress is conditioned upon the 

 development of tbese. No other science is so ill adapted as geogra- 

 phy to advance independently and without external aid. When the 

 astronomer aims at new applications of the theory of disturbance, 

 or when the physicist studies the phenomena of polarization ; when 

 the chemist undertakes to break up combinations of elements, or the 

 geologist investigates the relations subsisting between different strata, 

 each of these investigators labors in his own province, almost entirely 

 without reference to the progress made in other departments of 

 science. But when, on the contrary, a traveler, like the enterprising 

 Lieutenant Cameron, traverses broad continental regions over unex- 

 plored paths, the gain to scientific geography from such undertakings 

 in great measure depends upon the development of astronomy, meteo- 

 rology, geology, etc., inasmuch as it is by the aid of these sciences that 

 we can discuss the observations that have been made, and turn them 

 to account for ulterior conclusions. Then, too, we must not overlook 

 those sciences which have to do with organic Nature and which' con- 

 sider from higher points of view the distribution of living beings. 

 Bearing all this in mind, we can readily perceive how intimate is the 

 connection between geography and all the natural sciences. Hence 

 it is that in earlier times the idea of scientific geography could hardly 

 be entertained. At first geography offered little besides an imper- 

 fectly-arranged mass of descriptions of strange lands and curious 

 things; next it gradually invaded the domain of statistical facts; 

 then the relations of the history of man to the earth's configuration 

 were recognized and elucidated ; at last came scientific geography, 

 which investigates the relations between the structure of the earth 

 and the sum of all terrestrial phenomena, both organic and inor- 

 ganic. The following instance will show the distinction between 

 ordinary (descriptive) geography and scientific geography. 



No inconsiderable part of the surface of terra firma consists of des- 

 erts, those vast, dry, and in part sandy regions, the type of which is the 

 Sahara. The old descriptive geography gives the geographical situa- 

 tion of these wastes, their superficial extent, the number and site of 

 their oases, the names of the mountain-regions which traverse them, 

 and perhaps a few observations after the manuer of anecdotes upon 

 the intense heat which prevails in such regions, and the perils of a 

 journey through the desert. 



Scientific geography, on the other hand, regards these deserts as 

 an integral part of the terrestrial organism, and shows how their oc- 

 currence is not accidental, but a necessary result of the past and pres- 

 ent distribution of land and water, and of the position of the zone of 

 calms. It exhibits to us the process of forming deserts still active, 

 inasmuch as there exist centres of sand-radiation. It solves for us 

 the enigma of the formation of springs in the oases, inasmuch as it 



