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XII. Observations on M. Laplace's Communication to the Ro ml 

 Acadcmif of Sciences, " Sur I'Attraction des Spheres, et sur 

 la llcpulsion des Fliiides elastiques." Bij John Heiiapath, 

 Esq. 



/^N the first of May 1821, I published in the Annals of 

 ^^ Philosojihy a theory of gaseous bodies, mathematically 

 drawn from the Newtonian theory of heat. An announcement 

 of the publication and objects of the paper which contained 

 this theory, and which had been in the hands of the principal 

 members of the Royal Society from the May precedinjT, was 

 sent to the Marquis de Laplace in June 1821. On the 10th 

 of the following September, this nobleman communicated to 

 the Royal Acatlemy of Sciences a paper, whose professed ob- 

 ject is to demonstrate from the principles of caloric the known 

 laws of permanent airs, — the same that my paper contained. 

 Unfortunately I did not meet »vith M. Laplace's paper until 

 towards the tall of 1822; at which time I first saw it in the 

 Coniiaissance des Terns for 1824. 



Though it was obvious from the perfect coincidence of the 

 object ot M. Laplace's paper with that of a part of mine, and 

 its being presented to the Royal Academy so long after the 

 printing and notice of my paper, that his communication was 

 in consequence of mine and intended to supersede it, yet I 

 preferred leaving some instances of arguments and results, 

 which appeared to me in point of accuracy to be exceptionable, 

 to the comments of others, to making any observations on 

 them myself. Perceiving, however, by the Connaissance des 

 Terns for 1825, which I have lately received, that M. Laplace 

 has in that work as good as four papers in continuation of his 

 first; and that he has excited such an interest in the French 

 Board of Longitude, as to induce that body to issue a com- 

 mission to repeat some experiments on sound, for the purpose 

 of affording him the advantageof better results; I have thought 

 it necessary to throw together a few remarks, which may enable 

 philoso})hcrs more easily to estimate the success of M. Laplace's 

 investigations. 



In the views of corpuscular repulsion of airs, which Newton 

 proposed to philosophers to examine, he imagined that the re- 

 jnilsion of each particle extends to those jiarticles only which 

 immediately surround it. The reason, if a reason it can be 

 called, which I believe he assigns for this limitation, is the 

 similarity of a phaunomenon in magnetic attraction. Without 

 entering into a discussion of the difference of those plia-no- 

 nieuM, which arc as different and disi^imilar as they can well be, 



it 



