THE ATMOSPHERE 61 



across northern South America, central Africa, and south- 

 ern Asia. 



What must be one direct result of a continuous intense 

 heating of the surfaces of the immense water areas of this 

 region the Torrid Zone ? Name three causes that com- 

 bine to make the barometer readings relatively low along 

 the line where the sun's rays are all the time vertical the 

 so-called heat equator. 



3. As the hot moisture-laden air of the region of the heat 

 equator ascends, in what directions other than upward is 

 it likely to move in the upper air ? What change will occur 

 in its temperature as it rises? What then becomes true 

 of the amount of moisture this air can hold? What is 

 true of its density as a result of these changes? As this 

 upper air moves from the equator poleward, what becomes 

 true of its elevation above the earth's surface ? 



4. In moving northward from the equatorial region over 

 land areas of varying altitude, as on the continent of North 

 America, in what portion of the continent are these upper air 

 currents likely first to touch ground so that moving along 

 the surface they again become winds? What is likely to 

 be true of the character of any such winds fed by the descent 

 of upper air as regards (a) temperature; (6) moisture? 

 What other direction than northward will be taken by 

 this atmospheric condition resulting from the downpour of 

 upper air ? Why so ? What is likely to be true of the 

 barometer readings of the sections of country over which these 

 conditions shall in turn prevail ? 



5. With descending air currents in any one section of the 

 country, what may reasonably be expected in some adjoining 



