1 87 1.] The Fuel of the Sun. 459 



have calculated the theoretical density of the atmosphere 

 of the moon and of each of the planets, and compared 

 the results as severely as I could with the observed 

 facts. As Jupiter is 27,100 times heavier than the moon, 

 and between these wide extremes there are six planets pre- 

 senting great variations of mass, the probabilities of acci- 

 dental coincidence are overwhelmingly against me, and a 

 close concurrence of observed telescopic refraction and other 

 phenomena with the theoretical atmospheric density must 

 afford the strongest possible confirmation of the soundness 

 of the basis of my whole argument. Such a concurrence 

 exists, and some new and very curious light is unexpectedly 

 thrown upon the meteorology of Mars and the constitution 

 of the larger planets; the latter, if I am right, must be minia- 

 ture suns, permanently red- or white-hot, must have something 

 like a photosphere, surrounded by a sphere of vapour (the 

 outside of which we see), must have mimic spot vortices 

 and prominences, and in the case of Saturn must eject 

 volleys of meteoric matter, some of which should 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 

 astronomers 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 

 this earth by experimental 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 this 

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

 elements and compounds of the chemist, and the de- 

 monstrated forces of the experimental physicist, exist and 

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

 distribution described by the astronomer; this simple 

 postulate 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 of Jupiter, 

 follow as necessary consequences of an universal atmosphere." 



VOL. VIII, (O.S.) — VOL. I. (N.S.) 3 O 



