SOLAR SYSTEM. 



the surface of any of them, it is only necessary to consider their 

 masses and their magnitudes. The weight of a body placed 

 upon any planet is greater or less, cceteris paribus, than the 

 weight of a body placed upon the earth, just in proportion as4he 

 mass of matter in the planet is greater or less than the mass of 

 matter in the earth. If the distance from the surface to the 

 centre of the planet be double the corresponding distance in the 

 case of the earth, then the weight of bodies upon its -surface 

 would, on that account alone, be four times less than' in the case 

 of the earth. But if, at the same time, the mass of matter in the 

 planet were sixteen times greater than the mass of matter in the 

 earth, then the weight of bodies on the planet, on that account 

 alone, would be sixteen times greater. The weight, then, on. 

 the one score, would be sixteen times greater, and on the other, 

 four times less ; the result being that the actual weight under 

 such circumstances would be four times greater than upon the 

 earth. Such are the principles by which may be calculated the 

 weights of bodies upon the surfaces of the different planets. 



12. It has been found that the weights of bodies on the surface 

 of Venus are nearly the same as on the Earth, but that on 

 Mercury and Mars the weights of bodies are only half of those 

 which they would have if placed on the Earth. The inference 

 obviously is, that organised beings on Venus would require to be 

 endowed with the same bodily strength exactly as upon the Earth, 

 but that half the strength would suffice on Mars and Mercury. 

 The numerous analogies which we have indicated give the 

 highest degree of probability, not to say moral certainty, to 

 the conclusion that the three planets, Mars, Venus, and Mer- 

 cury, which, with the Earth, revolve nearest to the sun, are 

 like the Earth appropriated by the Omnipotent Creator and 

 Ruler of the Universe to races very closely resembling, if not 

 absolutely identical with, those by which the Earth is peopled. 



13. The solar system consists of the sun, a globe of stupendous 

 magnitude, maintaining a position, relatively fixed in the centre, 

 and thirty- three planets revolving round it in paths which do 

 not differ sensibly from, concentric circles. 



14. These thirty-three planets are characterised by very striking 

 differences in relative position and in magnitude, and have in 

 relation to these differences been classed in three groups. 



15. The inner group consists of four: Mercury, Venus, the 

 Earth, and Mars. They are all included within a circle ot 

 150,000000 of miles radius described round the sun as a centre, 

 the distance of the earth being nearly 100,000000 of miles. 



The circumstances attending these globes,- their mutual 

 analogies, and the probability, if not the moral certainty, that 



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