306 SCIENCE IK SHORT CHAPTERS. 



tional heat applied after this will have but one function to perform, 

 viz. the ordinary work of increasing the bulk of the heated body 

 without doing anything further in the way of conferring upon it any 

 new self-repulsive properties. 



Our notions of solids, liquids, and gases are derived from our 

 experiences of the state of matter here upon this earth. Could we 

 be removed to another planet, they would be curiously changed. On 

 Mercury water would rank as one of the condensible gases ; on Mars, 

 as a fusible solid ; but what on Jupiter ? 



Recent observations justify us in regarding this as a miniature sun, 

 with an external envelope of cloudy matter, apparently of partially 

 condensed water, but red-hot, or probably still hotter within. His 

 vaporous atmosphere is evidently of enormous depth, and the force of 

 gravitation being on his visible outer surface 2 times greater than 

 that on our earth's surface, the atmospheric pressure in descending 

 below this visible surface must soon reach that at which the vapor of 

 water would be brought to its critical condition. Therefore we may 

 infer that the oceans of Jupiter are neither of frozen, liquid, nor 

 gaseous water, but are oceans or atmospheres of critical water. If any 

 fish-birds swim or fly therein they must be very critically organized. 



As the whole mass of Jupiter is 300 times greater than that of the 

 earth, and its compressing energy toward the centre proportional to 

 this, its materials, if similar to those of the earth and no hotter, 

 would be considerably more dense, and the whole planet would have 

 a higher specific gravity ; but we know by the movement of its satel- 

 lites that, instead of this, its specific gravity is less than a fourth of 

 that of the earth. This justifies the conclusion that it is intensely 

 hot, for even hydrogen, if cold, would become denser than Jupiter 

 under such pressure. 



As all elementary substances may exist as solids, liquids, or gases, 

 or critically, according to the conditions of temperature and press- 

 ure, I am justified in hypothetically concluding that Jupiter is 

 neither a solid, a liquid, nor a gaseous planet, but a critical planet, or 

 an orb composed internally of dissociated elements in the critical 

 state, and surrounded by a dense atmosphere of their vapors, and 

 those of some of their compounds, such as water. The same reason- 

 ing applies to Saturn and the other large and rarefied planets. 



The critical temperature of the dissociated elements of the sun is 

 probably reached at the base of the photosphere, or that region 

 revealed to us by the sun-spots. When I wrote " The Fuel of the 

 Sun," thirteen or fourteen years ago, I suggested, on the above 

 grounds, the then heretical idea of the red-heat of Jupiter, Saturn, 

 Uranus, and Neptune, and showed that all such compounds as water 

 must be dissociated at the base of the sun's atmosphere ; but being 

 then unacquainted with the existence of this critical state of matter, 

 I supposed the dissociated elements to exist as gases with a small 

 solid nucleus or kernel in the centre. 



Applying now the researches of Dr. Andrews to the conditions of 

 solar existence, as I formerly applied the dissociation researches of 

 Deville, I conclude that the sun has no nucleus, either solid, liquid, 

 or gaseous, but is composed of dissociated matter in the critical state, 

 surrounded, first, by a flaming envelope due to the recombination of 

 the dissociated matter, and outside of this another envelope of 

 vapors due to this combination. 



