Masterpieces of Science 



certaining that fact, the capacity for heat for 

 the metal of which great guns are cast is not 

 sensibly changed by being reduced to the form of 

 metallic chips, and there does not seem to be any 

 reason to think that it can be much changed, 

 if it be changed at all, in being reduced to 

 much smaller pieces by a borer which is less 

 sharp." 



He next surrounded his cylinder by an oblong 

 deal-box, in such a manner that the cylinder 

 could turn water-tight in the centre of the box, 

 while the borer was pressed against the bottom 

 of the cylinder. The box was filled with water 

 until the entire cylinder was covered, and then 

 the apparatus was set in action. The tempera- 

 ture of the water on commencing was 60. 



"The result of this beautiful experiment," 

 writes Rumford, "was very striking, and the 

 pleasure it afforded me amply repaid me for all 

 the trouble I had had in contriving and arrang- 

 ing the complicated machinery used in making it. 

 The cylinder had b^en in motion but a short time, 

 when I perceived, by putting my hand into the 

 water, and touching the outside of the cylinder, 

 that heat was generated. 



"At the end of one hour the fluid, which 

 weighed 18.77 pounds, or two and one-half 

 gallons, had its temperature raised forty-seven 

 degrees, being now 107. 



"In thirty minutes more, or one hour and 

 thirty minutes after the machinery had been set 

 in motion, the heat of the water was 142. 

 158 



