COSMIC PHILOSOPHY 



if the movement is kept up for a sufficient length 

 of time, the oil-ring breaks into fragments, which 

 revolve like satellites about the oil-globe, and 

 each of which keeps up for a time its own move- 

 ment of rotation in the same direction with the 

 revolution of the ring. 



The common origin of the planets from the 

 sun's equator, as thus strikingly illustrated, ex- 

 plains at once the otherwise inexplicable coinci- 

 dence of their rotations, their revolutions, and 

 their orbital planes. At a single glance we see 

 why the planetary orbits are always nearly con- 

 centric and nearly in a plane with the solar 

 equator ; and we see that, since the sun must 

 always have rotated, as at present, from west to 

 east, the planets formed from him must have 

 kept up a revolution, and acquired a rotation, 

 in the same direction. 



Such is the grand theory of nebular genesis, 

 first elaborated with rare scientific acumen by 

 Kant in 1755, and afterwards independently 

 worked out by Laplace in 1796. The claims 

 of this theory to be regarded as a legitimate 

 scientific deduction have been ably stated by 

 Mr. Mill, in his "System of Logic," Book III. 

 chapter xiv. As we are there reminded, " there 

 is in this theory no unknown substance intro- 

 duced on supposition, nor any unknown pro- 

 perty or law ascribed to a known substance." 

 Once grant that the sun and planets are cooling 

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