230 NATURE AND PROPERTIES OF SOILS 



next and the northerly slope last. The amount of heat for 

 a given area is in the order of 106, 100, and 81, respectively. 



Fig. 43. — Diagram showing the distribution of a given amount of radiant 

 energy on different slopes on June 21, at the 42nd parallel north. 



These generalizations have been established by the work of 

 a number of investigators. 1 



Wollny 2 found near Munich that the temperature of south- 



1 King, F. H., Physics of Agriculture, p. 218. Madison, Wis., 1910. 

 a Wollny, E., Untersuchungen uber den Einfluss der Exposition auf die 



