256 THE FORCES OF INORGANIC NATURE. 



found by the author, a rise of temperature when violently 

 shaken. The water so heated (from 12 to 13 C.) has a 

 greater bulk after being shaken than it had before ; whence 

 now comes this quantity of heat, which by repeated shaking 

 may be called into existence in the same apparatus as often 

 as we please ? The vibratory hypothesis of heat is an ap- 

 proach toward the doctrine of heat being the effect of mo- 

 tion, but it does not favour the admission of this causal rela- 

 tion in its full generality ; it rather lays the chief stress on 

 uneasy oscillations (unbehagliche Schwingungen). 



If it be now considered as established that in many cases 

 (exceptio confirmat regulam) 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 assumption of a 

 cause without effect and of an effect without a cause -just as 

 the chemist, instead of allowing oxygen and hydrogen to dis- 

 appear without further investigation, and water to be pro- 

 duced in some inexplicable manner, establishes a connection 

 between oxygen and hydrogen on the one hand and water on 

 the other. 



The natural connection existing between falling force, mo- 

 tion, and heat may be conceived of 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 quantity 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 very easily led to 

 the equations between falling force, motion, and heat, that 

 have already been discussed. 



