37G M. J. R. Mayer on the Forces of Inorganic Nature. 



And what applies to the smallest particles of matter, and the 

 smallest intervals between them, must also apply to large masses 

 and to measureable distances. The falling of a weight is a real 

 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. 



But just as little as the connexion between falling force and 

 motion authorizes the conclusion that the essence of falling force 

 is motion, can such a conclusion be adopted in the case of heat. 

 We are, on the contrary, rather inclined to infer that, before it 

 can become heat, motion — whether simple, or vibratory as in 

 the case of light and radiant heat, &c. — must cease to exist as 

 motion. 



If falling force and motion are equivalent to heat, heat must 

 also naturally be equivalent to motion and falling force. Just 

 as heat appears as an effect of the diminution of bulk and of the 

 cessation of motion, so also does heat disappear as a cause when 

 its effects are produced in the shape of motion, expansion, or 

 raising of weight. 



In water-mills, the continual diminution in bulk which the 

 earth undergoes, owing to the fall of the water, gives rise to 

 motion, which afterwards disappears again, calling forth unceas- 

 ingly a great quantity of heat ; and inversely, the steam-engine 

 serves to decompose heat again into motion or the raising of 

 weights. A locomotive engine with its train may be compared 

 to a distilling apparatus ; the heat applied under the boiler passes 

 off as motion, and this is deposited again as heat at the axles of 

 the wheels. 



We will close our disquisition, the propositions of which have 

 resulted as necessary consequences from the principle ' ' causa 

 sequat effectum," and which are in accordance with all the phe- 

 nomena of Nature, with a practical deduction. The solution of 

 the equations subsisting between falling force and motion requires 

 that the space fallen through in a given time, e. g. the first second, 

 should be experimentally determined ; in like manner, the solu- 

 tion of the equations subsisting between falling force and motion 

 on the one hand and heat on the other, requires an answer to 

 the question, How great is the quantity of heat which corre- 

 sponds to a given quantity of motion or falling force ? For 

 instance, we must ascertain how high a given weight requires to 

 be raised above the ground in order that its falling force may 

 be equivalent to the raising of the temperature of an equal 

 weight of water from 0° to 1° C. The attempt to show that 



