262 Researches in the Theory and Calculus of Operations. 



The surface of the denser body (or medium) will therefore 

 have an overplus of force beyond that requisite to keep the 

 forces of the lighter medium at bay; which overplus may 

 pass through the latter media, and join with the general 

 emanating force of the whole substantial contents of the 

 earth (or Sun or planets, etc.), in forming what has been 

 termed the cether. This emanated force manifests itself as 

 heat, only when in spherical oscillation. Although a body may 

 be at (relative) rest in space, it is seldom at equilibrium in 

 time; for by the theory of exchanges (Prevost), the hotter 

 body is constantly drained to supply the cooler one, until 

 the exchange reaches par, and the perpetual change of tem- 

 perature of the media in which we live show that this is 

 very rarely the case, and very transitory when it does 

 happen. 



An elastic body rebounds when it strikes a harder one. 

 If A be the hotter body, A' will be the colder one if its 

 emanating forces are denser than those of A. Consequently 

 the latter will rebound, or oscillate spherically, when they 

 strike those of A'; and thus a pulsating pressure is returned 

 upon A, provoking a reaction similar in kind to the friction 

 before referred to, and similarly evolving a supply of ca- 

 lorific force, to enlarge the dimensions of A' at the expense 

 of reducing those of A, until a balance of thermometric 

 temperature is attained and the exchange is equalized. 



Dynamic vision should see the constantly emanating 

 forces continuously arriving at the limits A aad B, and 

 expiring successively in the effort which maintains equili- 

 brium each with its fellow and with the encountering me- 

 dium, by mutual annihilation. What is termed vis viva is 

 nothing else than this generating and generated force. 



11. Every physical phenomenon or occurrence whatever 

 is a change of place in space, either of some body in its en- 

 tirety, or of some portions thereof ; so that the term motion 

 stands as the summum genus including all the changes, the 



