114 NOMOS. 



tected in them. It is to be expected that the orbital 

 movement will diminish rapidly as the distance of 

 the planet from the Sun increases, and that the 

 rate of this diminution will, in all probability, be 

 inversely proportional to the square of this distance. 

 Now the planets do move with diminished rapidity 

 as their distance from the Sun increases, but not 

 after the required ratio. Thus, Mercury travels 

 162,400 feet in a second; Venus 118,800 feet; Mars 

 81,860 feet; Jupiter 44,297 feet; ^Saturn 32,715 

 feet; Uranus 23,070 feet; Neptune 18,435 feet. 

 The mot" on diminishes as the distance increases, and 

 the dimi .ution is considerable, but it is not at all 

 accordir , to the required law, for if the motive 

 force i uderwent no change except that which 

 obliges it to be inversely proportional to the square 

 of the stance, then taking the motion of Mer- 

 cury as a standard of comparison Venus ought to 

 travel 47,072 feet in a second; the Earth 24,421 

 feet; Mars 10,518 feet; Jupiter 843 feet; Saturn 

 267 feet; Uranus 66 feet; and Neptune 26 feet. 

 Where, then, is the error? Are we not to explain 

 the movements of the Earth upon the principles 

 which have been laid down, or is there some error 

 in the mode of applying these principles to the 

 movements of the other planets ? We can find no 

 HOW the dif- error > except it be an error to assume 

 that the same amount of resistance is 



mentioned is 



to be over- opposed to the movements of all the 



planets. This is, indeed, a question ; for 



it is quite possible that the resistance may vary in 



different parts of space, and that it may become less 



