PAGE 83 Analysis of the Nebular Hypothesis. Separation from the nebula of the rings for the separate planets, etc. 84 Excessive heat attributed to the nebula erroneous and impossible. 85 Centigrade thermometer to be used for temperatures. 86 Temperature of the nebula not far from absolute zero. 86 Erroneous ideas about glowing gases produced by collisions of their atoms, or particles of cosmic matter in the form of vapours. 87 Separation of ring for Neptune. It could not have been thrown off in one mass, but in a sheet of cosmic matter. 88 Thickness and dimensions of the ring. 89 Uranian ring abandoned, and its dimensions. 90 Saturnian ring do. do. 91 Jovian ring do. do. 93 Asteroidal ring do. do. 94 Martian ring do. do. 95 Earth ring do. do. 96 Venus ring do. do. 97 Mercurian ring do. do. 98 Residual mass. Condensation of Solar Nebula to various diameters, and relative temperatures and densities. 100 Unaccountable confusion in the mode of counting absolute temperature examined and explained. Negative 274 degrees of heat only equal 2 degrees of absolute temperature. 103 The Centigrade thermometric scale no better than any other, and cannot be made decimal. 104 The sun's account current with the Nebula drawn up and represented by Table III.
We may now proceed to take the original nebula to pieces, by separating from it all the members of the solar system, in performing which operation we shall suppose the divisions between the nebula and each successive ring to have taken place at a little more or less than the half distances between the orbits of two neighbouring planets, because we have no other data to guide us in determining the proper places. These divisions have manifestly been brought about in obedience to some law, as is proved in great measure by what is called Bode's Law; although no one has as yet been able to explain the action of that law. It is no doubt certain that a division must have taken place much nearer to the outer than the inner planet in each case, if we think of what would be the limit to the sphere of attraction between the nebula and a ring just detached from it--for the attraction of the abandoned ring, and even of all those that were outside of it, would have very little influence in determining the line where gravitation and centrifugal force came to balance each other--but the data necessary for calculating what these would be are wanting. Even if they existed the calculations would become too complicated for our powers as the number of rings increased; and for our purpose it is really of very little importance where the divisions took place. The breadths of the rings would be practically the same, whether they were divided at the half distances between, or much nearer to, the outermost of two neighbouring planets; and although the extreme diameters of the consecutive residuary nebulæ would be somewhat greater, their densities and temperatures would not materially differ from those we shall find for them as we proceed in our operations. Their masses would be the same in all cases, which is the principal thing in which we are interested.