248 THE GEOGRAPHY 



attribute an essential influence to light, pressure of the 

 atmosphere, &c., even though we may not be able to unfold 

 the how. 



We get the most definite notion of such a future de- 

 velopment of Science, when we make a close survey of its 

 past progress, and thus become aware how the gradually 

 increasing accuracy of the knowledge of determinate 

 physical conditions, has also rendered explicable here, many 

 phenomena which previously were very enigmatical. This 

 is most strikingly shown in the doctrines of the distribution 

 of warmth on the globe. Originally, as in the cases of 

 Halley, Euler and others, the attempt was made to refer 

 this distribution to the position of the earth in relation to 

 the sun, a proceeding which, for the moment, appeared 

 very admissible, since the sun is actually, if not the only, 

 yet certainly the most essential source of heat to the earth. 

 But in what violent contrast the so-obtained results stand 

 to the actual phenomena. Under such considerations the 

 temperature must naturally decrease regularly with the 

 increasing latitude ; but while the Russian army, on the 

 march to Chiwa, perished from cold under the 40th 

 degree of latitude, in the Faroes, under the 62nd degree, 

 the sheep remain at pasture through the whole winter. 

 All such calculations have, in fact, only value under the 

 assumption, that the whole earth is equably and homo- 

 geneously covered with substances on both sides of the 

 equator, which substances always have an exactly similar 

 relation to the heating rays and, finally, are always at 

 rest. Now not a single one of all these conditions is 

 fulfilled. We were, therefore, directed to immediate obser- 

 vation. It was found that even if the heat was differently 

 distributed, in reference to season, yet the same place had 

 pretty nearly the same temperature every year. If, for 



