BLASIUS'S THEORY OF STORMS. 



301 



will be condensed into masses of cumulus clouds banked up against 

 the top of the cold current, and arranged over the horizontal stratus 

 clouds. Thus is produced the combination of cumulo-stratus cloud, 

 as represented in Fig. 4, and which is characteristic of progressive 

 summer storms. 



Fig. 3. Stratus Clouds. 



To the tornado-cloud produced by a whirl of air, and resembling 

 an inverted cone, Prof. Blasius gives the name of conns, which is 

 both distinctive and appropriate. 



These four typical classes of clouds viz., cumulus, stratus, cu- 

 mulo-stratus, and conus indicate and characterize the four different 

 classes of storms. 



Prediction of Storms. With the foregoing facts and classifica- 

 tions in view, Prof. Blasius's method of predicting the approach of 

 storms, " by their embodiments the clouds," can be verified by any 

 careful observer of ordinary intelligence. 



Winter Storms. When in winter, while the wind is blowing 

 from the north, thin, hazy bands or stripes of stratus clouds appear 

 low in the southern horizon, it indicates that the warm current from 

 the south is flowing northward, sloping over the polar current, and 

 that the condensation of its vapor into clouds, by successive undula- 

 tions, has commenced in the upper and colder regions of contact. 

 More and more of these stratus clouds gradually appear, until they 

 cover the entire southern sky and reach' the zenith. This may require 



