<J(5 DR. Irvine's and dr. black's 



then have been juftified in the terms he has ufed. But here 



we have every thing fettled, and we are informed with the 



air of an ancient fophirt, that it is examined and found inluf- 



ficient. I am induced to make an obfervation or two on this 



examination, becaufe I am informed that the mathematical air 



which reigns through this part of this work has adually im- 



pofed on many. For this time, however, I believe it can be 



fhewn that it is no more than an air, and that this fubjeft is 



not yet finally fettled. 



Dr. Thompfon's Dr. Thompfon fays, at page 269, Suppl. Ency. Brit. " Dr. 



Dr'.Trv'inJ^s ^'■'''"^' ^^ Glafgow, advanced a theory on this fubjed dif- 



theory of heat, ferent from that of Dr. Black. The fpecific caloric of water 



That caloric being greater than that of ice, it requires a greater quantity of 



abforbcd by ice , ^ -r ■ ■ , • , t 



on its converlion ^^^'Oric to raiie it to a given temperature than it does to raile 

 into water jcc. The caloric therefore does not become latent, it only 



creafe°of tempe-^'^^^^^ ^^ ^^ ^° ^""^"^ *^^^ greater fpecific caloric of water. This 

 ratui-e) only theory was zealoufly adopted by Dr. Crawford. Dr. Black 

 /atoj/andTs"^ obferved very juftly, that it did not account for the produdion 

 really employed of fluidity at all. The fpecific caloric of water is indeed 

 tn keeping up the greater than that of ice; but how is the ice converted into 



temperature ° 



tuhUe the capa- Water? This is an objedion which the advocates for Dr. 

 ehy is increafedi Irvine^s or Dr. Crawford's theory, (as it has been improperly 

 does notexpkin c^''^^) will not eafily anfwer. Let us examine whether this 

 the aft of theory accounts for the apparent lofs of caloric. It follows 



u ion. from Mr. Kirwan's experiments, that the fpecific caloric of 



Argument of . ~ . , , 



Dr. Thompfon. water IS to that of ice as 10 to 9. Dr. Black proved, that as 

 The capacity of piuch caloric entered the ice as would have raifed it had it been 

 water is to that ^ ^ r < • ..i. -r t 



of ice as 10:9. water, 140". Let us luppole that it would only have railed 

 — Iceduring the ice 14-0; in that cafe the melted ice ought to have been of 

 wlfaTwo-Sd have the temperature of 158°, for 10 : 9 : : 140 : 12S, but it was 

 raifed water only 32*>. Therefore 126° of caloric have difappeared, and 

 d?c°efbi-'e have * *^^""°'' ^^ accounted for by the change of fpecific caloric. 

 raifed the ice at Nor Can the accuracy of Dr. Black's experiment be fufpeded ; 

 leaft as much if jj j^^g j^gg^j repeated in every part of the world, and varied 

 Jt had remained . ' •' i 1 1 c 1 



foHd ^whence m every pouible way. We cannot doubt, therefore, that 



it is inferred caloric Unites with fubftances, and caufes them to become 



ice or water fluid, or that there is in fad a caloric of fluidity diUerent from 



•ugbt to have fpec fic caloric." 

 _ oth^ Now nobody doubts Dr. Black's experiment, and it is not 



j26«, if the neceflary to our argument to have any doubt on that fubjed. 



ca^S"" °d ^'^' Thompfon gives U as a fair ilatement of Dr. Irvine's the- 



alone operated Ory, 



in the cafe : 



