712 THE UNIVERSE. 



The terrestrial surface is estimated at 196,000,000 square 

 miles, and the learned have calculated that to cover it com- 

 pletely would require a thousand kingdoms the size of 

 France. 



Our planet is entirely enveloped by a thick layer of air, 

 which forms round it the softest cushion imaginable, and of 

 which the depth, according to the calculations of Laplace, is 

 about twenty-six miles. Notwithstanding its apparent light- 

 ness, this atmosphere weighs heavily upon all bodies on the 

 earth, and exerts greater pressure in proportion as they of- 

 fer a larger surface. Physiologists consider that each of us 

 has a weight of about 32,000 Ibs. to support; but this great 

 weight is not usually felt, because it is counterbalanced by 

 a counter-action equal in all directions, so that the one de- 

 stroys the other. 



The earth is not rich in respect to satellites, possessing as 

 it does only one, which, however, is of dimensions ample 

 enough as compared to it ; this is the moon, the faithful 

 companion of its course. Other planets, it is true, like Ju- 

 piter and Saturn, are more richly endowed, and have from 

 four to eight satellites ; but, again, there are others which 

 do not possess any, as is the case with Venus and Mercury. 



From one pole to the other our globe is full of animation, 

 and on it life manifests itself with all its strength. In the 

 torrid zone, as well as in the frozen regions, the air, the 

 earth, and the depths of the sea have their animal inhabi- 

 tants and their plants, which have succeeded each other 

 from age to age. When one generation becomes extinct 

 another takes its place, displaying forms before unknown. 

 A series of new creations will doubtless yet follow, up to the 



