DAY AM) NKillT 259 



<>n the u round represents the earth's revolution 

 around the sun. 



"You can familiarize yourself in another way with 

 the double movement of the terrestrial globe, as 

 follows : place in the middle of a room a round table, 

 and on that table a lighted candle to represent the 

 sun. Then circle around the table, pirouetting on 

 your toes. Each of your pirouettes corresponds to a 

 turn of the earth on its axis, and your course around 

 the table corresponds to its journey around the sun. 

 Notice that in turning on your toes you present in 

 succession to the rays of the candle the front, one 

 side, the back, and the other side of your head, which 

 in our experiment may represent the terrestrial 

 globe; so that each one of its parts is in turn in 

 tin* light or in the shade. The earth does the sank-: 

 in turning it presents one after the other its differ- 

 ent regions to the rays of the sun. It is day for the 

 region that sees the sun, night for the opposite 

 <>n. That is the very simple cause of day and 

 niirht. In twenty-four hours the earth makes one 

 rotation on its axis. Of these twenty-four hours the 

 duration of the day and night is composed. " 



"I underhand very well the cause of the alterna- 

 tion of day and night," said Jules. "It is day for 

 the half of the earth that sees the sun, night for the 

 opposite half. Hut as the globe turns, each coun- 

 try comes in succession to face the sun while others 

 pass into the unlimited half. The lark that turns dn 

 the hearth presents, in the same way, each of its 

 Bides in turn to the heat of the flame." 



"On- ini-ht almost -;i\." ivinark.'d Kmile, "it is 



