708 THE UNIVERSE. 



the horrible mantle of ice perpetually threatening to invade 

 them. 



Compared to our globe and to the other orbs which it 

 enchains in their orbit round itself, the sun is of enormous 

 dimensions. It is about a million and a half times the bulk 

 of the earth, and has been calculated to contain seven hun- 

 dred times the mass of all the planets together which circu- 

 late in its system. 



Astronomers have not rested content with knowing the 

 volume of the sun ; they have attempted to estimate its 

 weight, and have succeeded. By comparing its weight with 

 that of the earth, they have made out that it would require 

 a large number of the latter to counterbalance it. If we 

 supposed the existence of a prodigious balance, which al- 

 lowed us to place the sun in one scale, we should have to 

 put 350,000 terrestrial globes into the other in order to 

 weigh it properly. 



The orbit of the earth is rigidly limited to 91,000,000 

 miles from the sun. Some planets roll at a much greater 

 distance from this luminary : others much nearer. He 

 scorches the one, and condemns the other to the empire of 

 eternal frost. Mercury, his nearest neighbor, almost in a 

 state of combustion, is only 37,000,000 miles off. Neptune, 

 which is doubtless all covered with ice, rolls in the furthest 

 orbit of the system at 2,854,000,000 miles from the blazing 

 star; and thus it only accomplishes its revolution in 164 

 years, which constitute its year ! 



However dazzling may be the splendor of the sun, it was 

 discovered 250 years ago to display here and there some 

 black patches ; very small, it is true, in comparison with the 



