BENJAMIN THOMPSON, COUNT RUMFORD 23 



pacity was the same at the same temperature, they might have 

 possessed different quantities of heat. 



Rumford's next step was to determine how much heat was pro- 

 duced by a certain amount of friction. If he had been content 

 with mere qualitative results, the world would have had to wait 

 longer for the law of the conservation of energy, but he had the 

 passion of the true scientist to express everything possible in defi- 

 nite figures, even if it was nothing more than the cost of pea-soup 

 or the loss of heat from a tea-kettle. 



The apparatus he used for the determination of this most 

 important constant of nature, the relation of heat to work, was a 

 brass six-pounder mounted for boring. Into the short cylinder 

 of metal left on the end of the cannon in the process of casting a 

 hole 3.7 inches in diameter was bored to a depth of 7.2 inches. 

 Against the bottom of the hole a blunt iron borer was held by a 

 pressure of 10,000 pounds and the gun was turned on its axis by 

 horse-power. A thermometer, wrapped in flannel, thrust into the 

 hole rose to 130 F. after 960 revolutions. The weight of the dust 

 produced by the borer was found to be only 833 grains Troy, yet 

 according to the caloric theory this small amount of metal must 

 have had enough heat squeezed out of it to raise the 113 pounds 

 of gun-metal 70 F. ! 



Next he fitted a box containing i8f pounds of water around 

 the cylinder, and in two hours and a half the water boiled. 



"It would be difficult to describe the surprise and astonishment 

 expressed in the countenances of the bystanders, on seeing so 

 large a quantity of cold water heated, and actually made to boil 

 without any fire. Though there was, in fact, nothing that could 

 justly be considered as surprising in this event, yet I acknowledge 

 fairly that it afforded me a degree of childish pleasure, which, 

 were I ambitious of the reputation of a grave philosopher, I ought 

 most certainly rather to hide than to discover." 



He then determined by experiment how much heat was given 

 off in burning wax candles, and calculated that it would require 

 4.8 ounces of wax to heat the water and the metal to the same 

 extent. 



