of the priiicipal Phcenomena of Heat, S4S 



separated from each other. The phaenomena also require 

 that the repulsive force should decrease more rapidly than 

 the attractive force. These premises being admitted, the fol- 

 lowing consequences may, if I do not mistake, be deduced 

 from them. For brevity's sake I omit the demonstrations, 

 presuming that they will be readily supplied by those versed 

 in mathematics. 



1. If a particle of heat approach a particle of solid matter, 

 it will either fall to the surface and remain there, or it will 

 describe a curvilinear orbit thereabout. According to the 

 direction and velocity of its approach, this orbit will either be 

 confined within a certain limit, like an ellipse, or will go off 

 to an infinite distance, like an hyperbola. To avoid circum- 

 locution, I will take leave to call these two classes of curves 

 respectively, ellipsoidal and hyperholoidal curves. A particle 

 of heat reposing on the surface of a particle of solid matter, 

 or revolving about it in an eUipsoidal curve, will have no ten- 

 dency to fly off or to pass into a contiguous body, unless dis- 

 turbed by some exterior force. It is therefore latent. 



It must not be supposed that latent heat exists only in fluid 

 or gaseous bodies. The phaenomena of softness and mallea- 

 bility must be considered as resulting from the presence of a 

 portion of heat in this state. Nay, it is probable that even 

 the hardest and most brittle substances are not entirely de- 

 prived of it. 



2. When a solid body is exposed to friction or percussion, a 

 certain number of the particles of heat which had evolved tran- 

 quilly in ellipsoidal curves are forced out of their orbits, and fly 

 off beyond the reach of the attractive force of the particle to 

 which they belonged ; just as our earth might be driven out 

 of the limits of the solar system by the stroke of a comet; sup- 

 posing the latter of sufficient density and magnitude. And 

 thus we have an explanation of the heat produced by friction 

 or percussion ; which has been supposed to form one of the 

 strongest objections to the corpuscular hypothesis. 



It confirms this theory, that a piece of iron which has been 

 heated by hammering becomes brittle^ indicating that a por- 

 tion of its latent heat has been lost, while sensible heat has 

 been disengaged. 



3. If we suppose a particle of matter to be of an oblong 

 form, or to have one of its axes greater than the others, the 

 particles of heat will collect chiefly about the middle of its 

 length. And thus we have an explanation of a remarkable 

 fact discovered by M. Mitscherlich, that crystallized bodies, 

 when heated, do not expand equally in all directions*. 



* See Phil. Mag., First Series, vol. Ixiy. p. 162; and Lond and Edinb. 

 Phil. Mag, vol. i. p. 413.— Edit. 



