60 LABORATORY LESSONS IN GENERAL SCIENCE 



Trace its possible course to make a complete round of 

 circulation. 



2. Trace the complete circulation made possible when 

 in one region of the country there is a warm moist atmos- 

 phere, and in some adjoining section the air is cold and dry. 

 How long will this movement of atmosphere be maintained ? 

 In what part of this circuit will the air current be along the 

 earth's surface ? Where will this air current cease to exist ? 

 Upon what will the velocity of the current largely depend? 



3. It may be well to distinguish between different parts 

 of this circulation of atmosphere by limiting the use of the 

 term wind to the current along the earth's surface as 

 distinguished from ascending, descending, and upper air 

 currents. Using the term in this way, infer (a) where a 

 "wind" originates (springs up); (b) where it ends (ceases 

 to be a wind) ; (c) from what direction it will blow. 



4. Where air currents are established, and regardless 

 of changes of temperature and of moisture, what will be 

 the effect on barometer readings (a) of the upward move- 

 ment of the atmosphere ; (b) of the downward movement ? 



AREAS OF HIGH AND LOW PRESSURE; 



1. In some parts of the world the sun at noon is directly 

 overhead is in the zenith. At what time of year is there 

 nearest approach to that condition here? What relation is 

 there between the temperature of a region and the obliquity 

 (ob-lik'wi-ti) of the sun's rays as measured by the angle 

 between them and vertical rays? 



2. That portion of the earth where the sun's rays are 

 always vertical, reaches east and west around the globe 



