62 LABORATORY LESSONS IN GENERAL SCIENCE 



section if an equilibrium of the atmosphere is to be main- 

 tained? What conditions of atmosphere in any region are 

 likely to favor the development there of an ascending cur- 

 rent? From how many directions will winds blow toward 

 these areas of low pressure? At the center of one of these 

 areas, why is there a "calm,"- an absence of all winds? 

 6. Describe the conditions of atmospheric circulation 

 exhibited in these diagrams : 



BROKEN CLOUDS CIRRUS CLOUDS 



HEAVY STRATUS CLOUDS 'T^TTI-I---- .-.,..-......- .;-?*^ ...... ^ ^ EAST 



DIRECTION 

 OF MOVEMENT 



FIG. 24. The theoretical movement of air in a " low." 



Air*. CIRRUS CLOUDS 

 '.'V s vSiKt ^ I FAR WEATHER 



CLEAR WEATHER PARTLY CCOUDY 



DIRECTION 

 OF MOVEMENT 



FIG. 25. The theoretical air movements of a "high." 



