36 SCIENCE IN SHORT CHAPTERS. 



finally settle down into orbital paths, and thus produce the 

 rings. 



These are startling conclusions, and when I reached them 

 they were utterly at variance with general astronomical 

 opinion, but I find since their publication that some astro- 

 nomers have already shown considerable readiness to adopt 

 them. In my case this view of the solar constitution of the 

 larger planets is not a matter of mere opinion, or guessing, 

 or probability, but it follows of necessity, and as stated on 

 page 200, " the great mystery of Saturn's rings is resolved 

 into a simple consequence, a demonstrable and necessary 

 result of the operation of the familiar forces, whose laws of 

 action have been demonstrated here upon the earth by ex- 

 perimental investigation in our laboratories. No strained 

 hypotheses of imaginary forces are required, no ethers or 

 other materials are demanded, beyond those which are 

 beneath our feet and around our heads here upon our own 

 planet; all that is necessary is to grant that the well-known 

 elements and compounds of the chemist, and the demon- 

 strated forces of the experimental physicist, exist and ope- 

 rate in the places, and have the quantities and modes of 

 distribution described by the astronomer; this simple postu- 

 late admitted, these wondrous appendages spring into 

 rational existence, and like the eternal fires of the sun, the 

 barren surface of the moon, the dry valleys of Mercury, the 

 hazy equivocations of Venus, the seas and continents and 

 polar glaciers of Mars, and the cloud-covered face Jupiter, 

 follow as necessary consequences of an universal atmos- 

 phere." 



If I am right in ascribing a gaseous condition to the sun 

 and the larger planets, and tracing the maintenance of this 

 condition to the disturbing gravition of the attendant 

 planets or satellites, a solution of the riddle of the nebulse 

 at once presents itself. We have only to suppose a star 

 cluster or group composed of orbs of solar or great planetary 

 dimensions, and that these act mutually upon each other 

 as the planets on our sun, or the satellites upon Saturn, 

 but in a far more violent degree owing to the far greater 

 relative masses of the reacting elements, and we obtain the 

 conditions under which great gaseous orbs would be not 



