30 OUR OWN WORLD 



The amount of heat received from the sun continues to 

 increase as long as the sun appears to move north. The 

 rays of the sun strike vertically the farthest point north on 

 the 22d of June. This is called the summer solstice. At 

 this time our days are the longest and our nights are the 

 shortest. But the days are not the hottest, as the heat 



A HUT IN THE TROPICS 

 Having thin walls, but a heavy thatched roof to keep out the rain. 



gradually accumulates for some time, more being received 

 each day than is given off. 



As the earth proceeds in its orbit from this point, the 

 inclination of the north pole toward the sun becomes less 

 and less, until on the 23d of September the sun is directly 

 over the equator. The north pole now begins to point 

 away from the sun. On December 22, the direct rays of 

 the sun fall upon the farthest point south, our days being 



