THE STARS AT NIGHT 3 



Of the total amount of heat radiated by the sun, the earth 

 receives only about one two-billionth. Yet this tiny frac- 

 tion of the sun's total heat furnishes practically all the energy 

 of the earth. It has stored the earth's crust with coal, 

 petroleum, and gas, from which we obtain heat, light, and 

 power. It lifts the waters to the hills and covers the hills 

 with verdure. It furnishes our food, the material for our 



SURFACE EXPLOSIONS ON THE SUN 



These gas flames shoot thousands of miles out from the surface of the sun. 

 They were photographed during an eclipse. 



clothing, and the very trees that shelter us from the mid- 

 day sun. 



The Evening Sky. As the light of the sun fades in the 

 evening, we see the stars coming out one by one until at 

 last the sky is studded with them. We notice, too, that the 

 brighter the star is, the sooner it appears. In the morning 

 just the reverse of this takes place : the stars begin gradually 

 to fade, and the brightest stars are the last to disappear. 



