106 



SCENERY OF THE HEAVENS. 



will represent the size and place of Mercury. A pea, at the distance of one hundred and 

 forty-two feet, will be the similitude of Venus ; and another, slightly larger, at two hundred 



and fifteen feet, will be the appropriate representative of 

 the earth. A good pin's head, removed three hundred and 

 twenty-seven feet from the central globe, will stand for Mars ; 

 and a few of the smallest grains of sand, placed at the dis- 

 tance of five hundred feet, will denote the Asteroids. An 

 orange of moderate size, distant a quarter of a mile, will 

 indicate Jupiter. Saturn may be shown by a lesser one, 

 at two-fifths of a mile ; and Uranus by a cherry, at three 

 quarters of a mile. 



There are remarkable differences as to the material of 

 the solar and planetary orbs. Their weight, compared with 

 that of the earth taken as 1, is, 



Venus. 



Earth. 



Mars. 



Ceres. 



Jupiter. 



Sun 

 355,000 



Mercury 



Venus 

 ft 



Mars 



Jupiter 

 338 



Saturn 

 95 



Uranus 

 17 



Their weight, compared with that of a globe of water of 

 the same size, is estimated to be 



Sun Mercury Venus Earth Mars Jupiter Saturn 



Uranus 

 1 



Saturn. 



Umnui. 



What striking diversities ! While our planet, weighed in 

 the balance against an equal volume of water, is four times 

 heavier, the matter of Mercury is four times heavier still, 

 while that of Saturn has only half the density of the fluid. 

 If cast therefore upon an ocean capacious enough to receive 

 them, Mercury would sink with as great a momentum as a 

 globe of lead, while Saturn would be buoyant as a vessel of 

 cork upon the deep. Upon the magnitude and density of 

 the planetary spjieroids, the force of gravity or the weight 

 of bodies at their surface depends. Hence, though the solar 

 substance is so much less dense than that of the earth, yet, 

 owing to its vast bulk, a man weighing 140 pounds at the 

 terrestrial equator would weigh more than 3500 at the 

 surface of the sun. Jupiter is still less dense, but on ac- 

 count of his superior magnitude the force of gravity at his 



surface is eight times as great as at the earth's, so that a terrestrial inhabitant transported 

 thither would be burdened with eight times his present weight, would move with eight 

 times the difficulty, and would fall with eight times the force. But upon the diminutive 

 telescopic planets, owing to their feeble gravity, a race of terrestrials might' play such 

 high fantastic tricks as would realise the dreams of fairy legends, bounding across a chasm 

 of no trifling span, with the same muscular effort as here will only enable us to compass a 

 step, and alighting with no greater shock than is felt in one of the paltry leaps of 

 childhood. We may however infer a nice adjustment between the planetary worlds and 

 their respective occupants, from the beautiful adaptation, which meets us here, of the 

 constitution of man, animals, and plants, to the circumstances of their dwelling-place. 

 Supposing that constitution to remain the same, and the earth's volume to be increased 

 to the size of Jupiter ; the intensity of the force of gravity would suspend the functions of 

 animal and vegetable existence. The tiger would cease to spring upon his prey from the 

 sheer impossibility of doing it ; the swift gazelle would become a laggard upon the plain ; 

 the soaring flight of the eagle would terminate ; the sap would fall in the trees to rise 



