342 Mr. J. Barton on the Physical Causes 



line being simultaneously impelled in a horizontal direction, 

 would, by virtue of their repulsion, cause a similar motion in 

 those immediately in front of them, whilst the latter particles 

 would tend to check the impetus of the former, and thus vi- 

 brations in the direction of transmission are simple to con- 

 ceive and easy to explain. But suppose the forces attractive. 

 Let the system of particles in a vertical line have a vertical 

 motion, and the slightest consideration will show us that the 

 immediate consequence is the production of a vertical motion 

 in the particles immediately in advance of them ; whilst, as 

 before, the reciprocal action of the latter particles tends to 

 impede the motion of the former. Here, then, we have as 

 clear a case as before, and our general conclusion from the 

 whole is, that repulsive forces allow of direct, attractive of 

 transversal, vibrations only." — (Trans. Camb. Phil. Society, 

 vol.vi.. Parti., p. 178.) 



The three equations of motion will then finally be reduced 

 to the form 



dt^ 

 dt^ 



= + 2c^ 



= - c^/3 



d^y _ _ 



dt 



= — C^y. 



The first of these I have developed in a paper read in May, 

 seeing reason for its application to the phsenomena of heat. 



[To be continued.] 



LXVI. On the Physical Causes of the principal Phcenomena 



of Heat, By John Barton, Esq,^ 

 TT has always appeared to me that the corpuscular hypo- 

 thesis is capable, with some modification, of affording a 

 more complete and satisfactory explanation of the phaenomena 

 of heat and light than the undulatory hypothesis. On the 

 present occasion I propose, without entering into any contro- 

 versial discussion, to show in what manner the principal phae- 

 nomena of heat may be deduced from the action of two forces. 

 An attractive force between the particles of heat and those of 

 solid matter, a repulsive force between the particles of heat 

 themselves. 



I assume that the particles of heat are very small in com- 

 parison of the particles of solid matter, and that these last are 

 very small in comparison of the intervals by which they are 



* Communicated by the Author. 



