24 GENERAL SCIENCE 



vertical over that whole portion of the globe. On the 

 twenty-first of June the rays of the sun fall vertically 

 on the Tropic of Cancer, 23 i north of the equator. The 

 sun has now reached its farthest point north, the days 

 being longest and nights shortest at this time in the 

 frigid and temperate zones. 



From autumn to spring the north pole is turned away 

 from the sun. It is then winter in the northern latitudes, 



SPRING 



sunriER 



AUTUMN 

 FIG. 20. Change of Seasons. 



and the days are shorter and colder than in the southern 

 latitudes. On December twenty-first the sun reaches 

 its most southern point, the direct rays falling on the 

 Tropic of Capricorn, 23 J south of the equator. In 

 its apparent moving from the Tropic of Cancer to the 

 Tropic of Capricorn and back, the sun seems to cross 

 the equator twice, the vertical rays falling on that imagi- 

 nary line about March twenty-first and September 

 twenty-third. 



