14 IN STARRY REALMS. 



as much heat as the earth. If this heat is to be lost ft 

 must be by passing out through the surfaces of the bodies. 

 The sun's surface is no doubt ten thou-and times that of 

 the earth ; but, on the other hand, there is a million times 

 as much heat to pass through the sun's surface as through 

 the earth's surface. Hence it follows that one hundred 

 times as much heat must emerge through every square 

 foot on the sun's surface as through every square foot on 

 the earth if the two bodies remain at equal temperatures. 

 The surface of the sun is in a state of the most tremen- 

 dous agitation. Look, for example, at Fig. 2, which 

 exhibits, on a small part of the sun's margin, some of the 

 glowing flames that leap from its surface. These out- 

 bursts are often tens of thousands of miles high, and they 

 indicate the fearful tempests with which the fiery globe is 

 convulsed. Such objects are known as the "prominences," 

 but the surroundings of the great luminary include also 

 the corona. This is a faint pearly light extending to a 

 vast distance round the sun, and rendered visible when 

 the moon intrudes between the earth and the sun, so as to 

 form a total eclipse. 



