HISTORY OF DYNAMICAL THEORY OF HEAT. 211 



Lave gained the unqualified recognition which they most certainly 

 deserve. 



Taking the casting of a brass cannon, solid and rough as it came 

 from the foundery, and with the cylindrical mass of metal a (Fig. 1), 

 called the verlomer Kopf, still adhering to the muzzle, Rumford caused 

 to he turned upon the superfluous end a smaller cylinder, b (Fig. 2), 



Fig. 1. 



Fig. 2. 



7f inches in diameter and 9.8 inches long, and which remained con- 

 nected to the cannon proper by the neck, e, 2.5 in diameter and 3.8 

 inches long. 



The whole mass being then secured in the apparatus used for bor- 

 ing (Fig. 2), a cavity 7.2 inches long and 3.7 in diameter was bored 

 in b, in the direction of its axis, so that a metal bottom, 2.6 inches 

 thick, remained between the borer and the neck. In this also a small 

 round hole, c d (Fig. 3), was radially bored for the insertion of a 

 thermometer. The cylinder, neck, etc., are represented upon a some- 

 what larger scale in Fig. 3. 



Fig. 3. 



~\ 



The borer used to create friction upon this metallic bottom was a 

 flat piece of hardened steel, 0.63 inch in thickness, four inches long, 

 and nearly as wide as the cylindrical bore in which it turned, 3^ 

 inches ; so that the area of contact with the bottom was about 2.33 

 square inches. This borer was securely held in place against the bot- 



