ClouD formation, W 



the Alps. Almost every day in summer there 

 appears above the peak of Mount Blanc a 

 beautifully formed cloud cap standing some 

 distance above it and hollowed out under- 

 neath like an inverted cup. Although this 

 cloud appears to be stationary, it is under- 

 going a rapid change; the moisture rises from 

 the snow-capped peak as invisible vapor to a 

 certain distance, where it is condensed into a 

 cloud of wonderful brilliancy. As the cloud 

 globules float upward they are absorbed into 

 the atmosphere again, as invisible moisture at 

 the upper limit of the cloud. If the wind 

 happens to be blowing, another phenomenon 

 takes place, giving the appearance somewhat 

 of a volcano. It is blown off from the peak 

 in the direction of the wind, but within a 

 short distance it strikes a warmer stratum of 

 air, where it is absorbed and assumes the 

 transparent condition. 



If we ascend a high mountain, we get some 

 idea of the altitude of the various forms of 

 cloud. A thunderstorm may be in progress 

 far below us, while the sun may be shining 

 from a clear sky above, with perhaps the ex- 

 ception of the frost clouds that we have re- 

 ferred to floating high above the mountain 

 tops. 



We have now described in a general way 

 how clouds are formed, how they are con- 

 densed into rain, and how moisture is dis- 



