THE SEASONS 73 



the sun. In winter time the north end of the axis is turned 

 away from the sun, and the latter appears lower in the sky, or, 

 in other words, in a very northern locality, the sun may not 

 rise above the horizon. 



References : 



1. 1002 : 177-180. The Cause of Seasons. 



2. 1103 : 40-42. Temperature Changes during the Revolu- 



tion of the Earth. 



3. 1304 : 397-401. The Cause of Seasons Explained. 

 a. 1004 : 95-99. The Seasons. 



6. 1302 : 19-22. The Change of Seasons. 



c. 1303 : 46-49. Seasons and Zones. 



d. 1305 : 52-53. The Seasons. 



e. 1309 : 29-31. The Change of Seasons. 

 /. 1310 : 341-346. The Seasons. 



g. 1311: 20-26. The Motions of the Earth and the Seasons. 

 h. 1312:23-24, The Seasons. 



Experiment 25. The Seasons Length of Day and Night. 



Apparatus : A small globe. 



a. Place the globe so that it receives light from a window, 

 or from some artificial light at least ten feet distant. Turn 

 the globe so that the north end of its axis points at right 

 angles to an imaginary line drawn from the globe to the 

 source of light. How much of the whole globe is illuminated ? 

 How much of the equator ? How much of the sixtieth parallel 

 of latitude? 



6. Turn the axis of the globe so that it points in the general 

 direction of the window. How much of the whole globe is illu- 

 minated ? How much of the equator ? How much of the thir- 

 tieth parallel ? How much of the sixty-sixth parallel ? Since 

 the illuminated part indicates day, what is the length of day 

 and night in each latitude ? (Count the meridians of latitude.) 



