THE CONSERVATION OF ENERGY 



cases no other effect of motion can be traced except 

 heat, and that no other cause than motion can be found 

 for the heat that is produced, we prefer the assump- 

 tion that heat proceeds from motion to the assump- 

 tion of a cause without effect and of an effect without 

 a cause. Just as the chemist, instead of allowing 

 oxygen and hydrogen to disappear without further 

 investigation, and water to be produced in some in- 

 explicable manner, establishes a connection between 

 oxygen and hydrogen on the one hand, and water on 

 the other. 



"We may conceive the natural connection existing 

 between falling force, motion, and heat as follows: 

 We know that heat makes its appearance when the 

 separate particles of a body approach nearer to each 

 other ; condensation produces heat. And what applies 

 to the smallest particles of matter, and the smallest 

 intervals between them, must also apply to large 

 masses and to measurable distances. The falling of a 

 weight is a diminution of the bulk of the earth, and 

 must therefore without doubt be related to the quan- 

 tity of heat thereby developed; this quantity of heat 

 must be proportional to the greatness of the weight 

 and its distance from the ground. From this point of 

 view we are easily led to the equations between falling 

 force, motion, and heat that have already been dis- 

 cussed. 



" But just as little as the connection between falling 

 force and motion authorizes the conclusion that the 

 essence of falling force is motion, can such a conclusi- >n 

 be adopted in the case of heat. We are, on the con- 

 trary, rather inclined to infer that, before it can be- 



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