ANALYSIS OF SOME ANCIENT BONES. ^Q 



tuation, which necessarily takes place in elastic metals like 

 zinc, do not resume the quantity of heat they have imparted 

 to the water? and if this hypothesis explain the little heat 

 of the 10th experiment, how does it apply to the great quan- 

 tity produced by the simple pressure in the first, second, and 

 third experiments? In discussing these facts, we are led to 

 the following consequences. If the calorific phenomena 

 produced by friction depend on a particular fluid called into 

 action by this process, either this fluid is extricated from the 

 pores of the metal by condensation, or it is drawn off and 

 taken away from the surrounding bodies like the electric 

 fluid. In the first case, the heat must diminish by conden- 

 sation, must follow the inverse ratio of the density, and must 

 be exhausted; in the second it must be modified by the in- 

 sulation of the substances rubbed : which did not take place 

 either in my experiments, or in those of count Rumfoid. 

 If on the contrary these phenomena are produced solely by an(J in tJ)at of 

 the internal agitation of the particles, the quantity of heat vibrations of 

 should diminish by condensation, and exhibit some propor- 1 e l )arice9, 

 tion to the density and more particularly to the elasticity of 

 the metal. Such are the doubts, that still obscure the ques- 

 tion concerning the cause of the heat produced by friction, 

 and require farther experiments. It is sufficient for me to 

 have opened the way, and shown its importance and its dif- 

 ficulties. 



VIII. 



Abstract of a Paper read to the Institute the 21st of July, 

 1807 , by Messrs, Fourcroy and Vauqublin, on some 

 Bones found in a Tomb in the Church of St. Geneviva*. 



I HESE bones were in general extremely fragile; but R 

 their heads were particularly so, owing to their great poro- tender, 



sitv. 



Their colour is purple, much resembling that of dried purp i e 

 * Annales d« Chimie, Vol.LXIV, p. 190. 



wine 



