feme heated Bodies in cooling. 177 



weighed at intervals, when it had been in the 

 fcale fix hours, and had then loft fo much of 

 its hear, as to be only blood warm, was found 

 to be acquiring weight in the proportion of 

 feven grains in the fpace of an hour*. But, 

 when weighed the day following, at the expira- 

 tion of twenty-four hours after the commence- 

 ment of the experiment, it had acquired a ftill 

 further addition of two pennyweights and feven- 

 teen grains, which, according to the above 

 progrefTion, it would have required at leaft nine 

 hours and a half, nay, moft probably, even a longer 

 time, to accomplifh. If to thefe nine hours and 

 a half, we add the preceding fix, we obtain 

 fifteen hours and a half j a period long before 

 the expiration of which, the mafs of iron muft 

 have taken the temperature of the furrounding 

 bodies, fince the firft fix of thefe were fufficient 

 to reduce it, from the welding point, down to 

 blood heat. 



I will not trefpafs longer on the time of the 

 Society, but will conclude by obferving, that 

 metals, which are the only bodies hitherto em- 

 ployed to determine this point, are certainly, 

 from the changes they undergo by the aftio.n 



• During the two fifft hours of its expofure in the fcale, 

 the increafe of weight had proceeded with much more 

 rapidity ; in the third hour it proceeded lefs quickly, 

 and continued to dirainilh gradually ia celerity to the 

 expiration of the fixth. 



Vol. III. N o£ 



