the Weight ascribed to Heat. - 19 



pounded ice and sea salt, till it had acquired the tem- 

 perature of 25 F. (7 degrees below the point of freez- 

 ing water), when it was carefully weighed, and found 

 to weigh very exactly 773 Jf- grains Troy. 



At i h. 30/72. P. M., the same bullet having been ex- 

 posed 30 minutes in a clean, dry vessel of porcelain, 

 placed in a sand heat, at the temperature of 212 F., or 

 that of boiling water, was again weighed, while yet hot, 

 and found to weigh no more than 773^ grains. 



At 2 h. o m. P. M., the bullet having now been ex- 

 posed 15 minutes, in a clean new Hessian crucible, 

 well covered, to the heat of a strong charcoal fire, and 

 being thoroughly red-hot, was found to weigh 773 f 

 grains. 



The bullet, being yet red-hot, was put again into the 

 crucible, and being once more exposed to the fire, which 

 now burned very bright, at ih. 20 m. it had acquired a 

 white heat, and began to show signs of melting, some 

 small bubbles appearing upon its surface. In this state 

 it was taken from the fire, and very carefully weighed 

 sixteen times successively, at different intervals, when 

 it was found to weigh as follows : 



Time when weighed. Was found to weigh. 



