Dr. J. R. Mayer on Celestial Dynamics. 387 



short paper in Liebig's Annalen, he had no equal. In 1845, 

 when he published his ' Organic Motion in connexion with Nu- 

 trition/ he had, in this field, no equal; and in 1848, when he 

 published his ' Celestial Dynamics/ he was without an equal in 

 this particular domain. This I state as my profound and deli- 

 berate conviction, but I should be extremely sorry to throw 

 mud at any man who holds a different belief. Happily the 

 English public will soon have an opportunity of forming its 

 own judgment on these matters from the translations of Mayer's 

 papers which are now appearing in the Philosophical Magazine. 



MIL On Celestial Dynamics. By Dr. J. R. Mayer. 



[Continued from p, 248.] 



THE movements of celestial bodies in an absolute vacuum 

 would be as uniform as those of a mathematical pendulum, 

 whereas a resisting medium pervading all space would cause 

 the planets to move in shorter and shorter orbits, and at last to 

 7 all into the sun. 



Assuming such a resisting medium, these wandering celestial 

 bodies must have on the periphery of the solar system their 

 cradle, and in its centre their grave ; and however long the 

 duration, and however great the number of their revolutions may 

 be, as many masses will on the average in a certain time arrive 

 at the sun as formerly in a like period of time came within 

 his sphere of attraction. 



All these bodies plunge with a violent impetus into their 

 common grave. Since no cause exists without an effect, each of 

 these cosmical masses will, like a weight falling to the earth, 

 produce by its percussion an amount of heat proportional to its 

 vis viva. 



From the idea of a sun whose attraction acts throughout 

 space, of ponderable bodies scattered throughout the universe, 

 and of a resisting aether, another idea necessarily follows — that, 

 namely, of a continual and inexhaustible generation of heat on 

 the central body of this cosmical system. 



Whether such a conception be realized in our solar system 

 — whether, in other words, the wonderful and permanent evolu- 

 tion of light and heat be caused by the uninterrupted fall of 

 cosmical matter into the sun — will now be more closely examined. 



The existence of matter in a primordial condition (Urmaterie), 

 moving about in the universe, and assumed to follow the attrac- 

 tion of the nearest stellar system, will scarcely be denied by 

 astronomers and physicists; for the richness of surrounding 

 nature, as well as the aspect of the starry heavens, prevents the 

 belief that the wide space which separates our solar system from 



