1^8 Ed'amination of the received DoSlrlnes 



the proportion which this difference in the width of the gauge 

 at its narroweft cud might bear to the whole of its prefent 

 width at the fame end, lliould be accurately afcertaincd to 

 enable chcniiOs in diHerent countries to obtain a uniformity 

 \n their refalts. 



XX, An Attempt to prove that the Matter of Heat y like other 

 SubJIances, pojjejfes not only Volume hut Gravity ; being a 

 ' Second EJfay on Caloric, By ALEXANDER TiLLOCH. 

 Read before the Afkejian Society Novemher 1800. 



I 



N the hafty eflay read before this Society in the eourfe of 

 ourjaft feflion * T ventured to call in queftion the truth of 

 certain commonly received do6irines refpe6ling heat or ca- 

 loric, mentioned feveral fa^ls which admit of conclufions 

 very diflerent from thofe which have been drawn from them 

 to fupport the do6lrines referred to ; and endeavoured to 

 iliow that heat retains uniformly the fame charafter, proper- 

 ties, and mode of a6tion; in oppofition to thofe who contend 

 that it is {omtixmt^ fenfible or free y and at other times latent 

 or fixed, 



1 alfo endeavoured to prove that heat is a real diftinft fub- 

 ftance, and not a mere quality or accident refulting from the 

 modification of matter. I fhowed, by many proofs, that it 

 poireflTes volume, which is a charaderiftic of matter ; that, 

 when expelled by chemical combinations, the volume of the 

 compound is lefs than the fum of that of the ingredients ; 

 and that, probably, the diminution is exactly equal to the 

 volume of the heat that has been thrown out : that, on the 

 oilier hand, when the compound is increafed in volume, it 

 has acquired, from the contiguous bodies, a portion of ca- 

 loric, probably, exa6lly equal in volume to that increafe : 

 and, to be brief, that the general laws enumerated in my 

 former eflay, and which, I believe, are univerfally admitted, 

 being fufficient to explain all the known phaenomena, with-r 

 put having recourfe to the dodlrine of latent^ as dillin-. 



' c^cc fbihfopbicul Magazine^ yoi. VII l. p. 70, 119, and 311. 



guiOlQcl 



