1822.] Mathematical Principles of Chemical Philosophy. 429 



The force, therefore, varying as the inverse cube or fourth 

 power of the distance, does not exist ; if it did, it would not be 

 able to produce the observed effects, as it could not be purely- 

 corpuscular ; but these forces are purely corpuscular, and depend 

 not upon the mass of matter concerned, but merely upon the 

 intensity of the attracting force, and the absolute distance of one 

 attracting surface from another. This action will be considered 

 in the next paper : in the remainder of the present communica- 

 tion, I shall proceed to an examination of the nature of that 

 vibratory motion which has been supposed to produce the phe- 

 nomena of heat. 



In a former paper, I examined some parts of this hypothesis, 

 and stated some reasons which induced me to adopt that which 

 supposes heat to be real matter : I shall now demonstrate this^ 

 intestine motion to be impossible. The particles of all matter 

 are known to attract each other ; and the direction of the force 

 is invariably that of right lines meeting at the centre of the body^ 

 if spherical ; and always meeting in it ; therefore, when two 

 bodies, whatever be their magnitude or figure, attract each other, 

 they move in a right line which passes through them until they 

 come into contact ; after which, they remain at rest. Now if 

 sulphuric acid and water be mixed, heat is excited, and the 

 volume is diminished : the particles, therefore, are nearer to 

 each other than they were before mixture. If the heat excited 

 result from any vibratory motion, it must continue so long as the 

 heat can be perceived ; it, therefore, cannot be a motion whicli 

 is in the direction of a right line joining the centres of the parti- 

 cles ; for this brings them together, and produces a state of rest; 

 the vibrations then must take place in a direction which is 

 oblique to this line. Let us, therefore, see what sort of motion is 

 possible. That one particle cannot oscillate about another as its 

 centre, or about the centre of gravity of the two, is too evident 

 to require any proof; but one may oscillate between two. Let 

 A and F be two equal particles of matter 

 placed at any given distance from each q 



other; a third, B, may be made to oscillate 

 between them in the right line C D, equi- 

 distant from them, and at right angles ; let _ 



1 ^ 



the force of attraction vary as — (D being 



the distance, and n the index) ; but E and 

 F, and E and A, and A and F, will always 

 attract each other ; let B be at E ; the force 

 with which it acts upon A and F to bring them together, or in 



the direction A F, is as r——-—' while A and F attract each other 



in the same direction, force being as -j^ ; therefore in a medium 

 perfectly free from all resistance, the motion must soon cease. 



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