92 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 



meters per hour. In this connection it is, indeed, to be remembered 

 that we have assumed exceptionally favorable conditions for the 

 precipitation in that we have assumed the onflowing air to have been 

 already fully saturated throughout the whole 4000 meters in depth 

 of the layer between y and y.' 



The comparison of the curve of precipitation with the curve of 

 profile in fig. 1 shows that although the maximum of precipitation 

 coincides with the maximum gradient of the slope of the mountain, 

 yet the depth of precipitation diminishes more slowly toward the 

 plane of the valley and the plateau of the mountain than does the 

 slope of the earth's surface; thus, for instance, the latter slope at 

 the point where % — ± A/12, and which is given by drj/d x, amounts 

 only to 1/20 of the maximum slope, while the precipitation at this 

 point is more than 1/5 of its maximum value. Therefore, under the 

 conditions here assumed, the effect of a mountain slope in producing 

 precipitation makes itself felt in the plain lying in front of the foot 

 of the slope. All of which agrees with actual experience. 8 The 

 fact that in reality the maximum precipitation appears to be pushed 

 more toward the ridge of the mountain is certainly partly explained, 

 as well as suggested, by the horizontal transportation of the pro- 

 ducts of condensation in the clouds, but also in part by the departure 

 of the real distribution of temperature and moisture from that here 

 assumed. (See Section IV, page 95.) 



The determination of the total quantity of precipitation caused 

 by the mountain slope will be attained if we integrate the value 

 of W as determined by equation (14) as a function of x between the 

 limits x = — A/ 4 and x = + A/4. The result is, therefore, 



. x x 



"*" T y' + 4 



= \W(x)dx = - \eF'(y) Cvdx. . . .(16) 



\W(x)dx = - f sF' (y) Cvd 



Vo X 



In this equation, according to equation (13) we have: 



+ 4 



C vdx = a X 1100 i e~\ v - 2 e~\ v + * e~\ v 

 J I 9 25 



X 1 



~ 1 



•Harm: Climatology, 2d Edition, Vol. I, p. 295; also Assmann, Einfluss 

 der Gebirge auf das Klimat von Mittel Deutschland, p. 373, 1886. 



