174 ■^'"' ^' li^n^y ^^ ^^^ JVeight acquired hy 





Conjectures relative to the Cause of the In- 

 crease of Weight acquired by Jome heated 

 Bodies, during cooling; by Thomas Henry, 

 junior. Communicated by Thomas Henry, 

 F. R. S. ^c. 



READ MARCH 28, I786, 



MANY experiments have been made by 

 different perfons, with a view to deter- 

 mine, whether the addition of aftual heat to 

 bodies does increafe their weight. M. BufFon 

 has aflerted, that a ball of iron, weighing, when 

 cold, 491b. iioz. increafed in weight, when 

 made of a white heat, in the proportion of 19I 

 grains to every pound. But, it is very proba- 

 ble, that, in this experiment, there was fome 

 fallacy, fince we find it diredly contradidory 

 to the refults both of the experiments made by 

 Dr. Roebuck*, and of thofe made by Mr. 

 Whitehurftf. The firft of thefe two Gentlemen 

 found, that a cylinder of wrought iron, heated 

 to a welding heat, at which time it weighed, 

 in a very accurate balance, fifty-five pounds, 



* Phil. Tranf. vol. LXVI. t lb. 



gradually 



