ON THK MATERIALITY OF CALORIC. ]<)t) 



tained that common; air conducts caloric better than it is con- 

 veyed through a vacuum, as 1000 is to 702, it may be exact- 

 ed that the ratio will hold in all intermediate degrees. 



In Count Rum ford's mafterly experiment, the metal, fub- -In Count Rum- 

 milted to friction, was .encompailed by water ; and air w^^L^Wd'of. 

 carefully excluded from the furfaces in motion. Yet the water Jour. 410, II. . 



became hot, and was kept boiling: a considerable time. In this™ }> ^ awric p 



' , . . might be fup- 



Ca-fe, the only obvious fource of caloric, from without, was po fed to be ab- 



through the borer employed in producing the friction ; if it bej^ JJ^^jJJ" 

 true, as the Count 1 has obferved, that the water could not, at'time. 

 the fame irtllanitj be in the act of giving out and receiving heat. 

 The fame objection to the communication of heat,, from an 

 tenia! fource, exiftValfo in thus explaining Mr. Davy's experi. 

 ment : but I cannot admit that the argument is demonftrative,' 

 in proving the evolved caloric not to be derived from extendi 

 fubftancesj for no abfurdity is implied in fuppofing, that a 

 body may be receiving caloric in one ftate, and giving it out 

 in another. We have an example of the fimultaneous admif- 

 iion and extrication of a fubtle fluid, the materiality of which is 

 admitted by Mr. Davy-, in an excited electric, which, at the Inftance in dec- 

 very fame intrant, receives the electric fluid from without, and tric,t y* 

 transfers it to the neighbouring conductors. In an ignited 1 

 body> alio, the two procetTes of abforption and irradiation of 

 light, are, perhaps, taking place at the 'fame moment. 



II. Another caufe of the increafe of temperature in bodies, In bodies which 

 is the liberation of their combined caloric: and, if this be a ! ¥?* h ^ at , by , 



' ' friction ; but do 



fource of temperature, the abfolute quantity of caloric in a body' not have their 



muft be diminifhed by friction. That no fuch diminution really »P*% dil ™- 

 , , • , . . . . . . .mined y 



takes place, we have the evidence of two experiments — the 



one of Mr. Davy, the other of Count Rumford. Mr, Davy, 

 by rubbing together two pieces of ice, converted them into 

 water. Now water, ex hypothefi, contains more caloric than 

 tbe ice from which it was formed; and, on the fame hypothe- 

 sis, the abfolute quantity of caloric in ice is diminiuied by fric- : 

 tion and liquefaction, which is abfurd. Count Rumford alfo' 

 ascertained, that the fpeci'ic heat of iron was not diminifhed' 

 when converted by a borer into turnings, and confequently 

 when it had been the fource of much temperature. In expla-i* ma y be f°P* 

 nation of thefe facts, we may be allowed to aflume the commu- P °^ f rom with- 

 nication of caloric from furrounding bodies, till this communi-outj 

 cation has been demonftrated to be impoflible. But even were 



the 



