Mr. R. H. M. Bosanquet on the Theory of Sound. 271 



different thing from the nebular theory of Laplace. Laplace 

 did not attempt to account for the origin of the sun, of the 

 stars, of the comets, or of the meteors. Neither did he assign 

 any cause for the solar rotation. After assuming that the 

 atmosphere of the sun had been suddenly expanded by some 

 extraordinary and unknown cause, he did not prove that, on 

 contracting again, the velocity of rotation could become so 

 rapid as to make the centrifugal equal to the centripetal force, 

 and thus abandon rings to form planets and satellites. Hence, 

 in giving his theory to the world, he says, " This origin of the 

 arrangements of the planetary system I offer with all that dis- 

 trust which every thing ought to inspire which is not the 

 result of observation or calculation." Neither did he write 

 any thing which indicated a surmise that gravity was the force 

 which in the beginning imparted all their velocities to all the 

 stars. 



Hitherto it has been claimed for no one, except for Compte, 

 that he had calculated the velocity of nebular rotation. But 

 really he came far from doing this. He simply assumed that 

 at the planetary orbits the centrifugal and the centripetal forces 

 in the solar nebula became equal ; and then he computed what 

 must have been the velocity of nebular rotation to produce 

 this equipoise. He found, on that assumption, that the equa- 

 torial velocity must have coincided with the present planetary 

 velocities, excepting only one forty-fifth part of the present 

 velocities of the planets. But this is solving a very different 

 problem from what is demanded. We demand to know how 

 and why the nebular and planetary velocities became what 

 they are, how and why the centrifugal and centripetal forces 

 became equal. This I have answered. Moreover he could 

 not understand the reason of the discrepancy in his calcula- 

 tions between the nebular and planetary velocities — one forty- 

 fifth part. This I found to arise from the wrong determina- 

 tion of the earth's distance from the sun, 95 millions of miles 

 instead of 92 millions. 



Philadelphia, Feb. 5, 1877. 



XXXVI. Notes on the Theory of Sound. By R. H. M. Bo- 

 sanquet, Fellow of St. John's College, Oxford. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



IN a revision of this subject recently undertaken with a view 

 to the preparation of an elementary treatise, I have come 

 across a few points which seem of sufficient interest to be 



