A HISTORY OF SCIENCE 



from the description, that the hollow, metallic cylinder 

 would occupy the middle of the box, without touching 

 it on either side; and that, on pouring water into the 

 box and filling it to the brim, the cylinder would be 

 completely covered and surrounded on every side by 

 that fluid. And, further, as the box was held fast by 

 the strong, square iron rod which passed in a square 

 hole in the centre of one of its ends, while the round or 

 cylindrical neck which joined the hollow cylinder to 

 the end of the cannon could turn round freely on its 

 axis in the round hole in the centre of the other end of 

 it, it is evident that the machinery could be put in 

 motion without the least danger of forcing the box out 

 of its place, throwing the water out of it, or deranging 

 any part of the apparatus." 



Everything being thus ready, the box was filled with 

 cold water, having been made water-tight by means of 

 leather collars, and the machinery put in motion. 

 "The result of this beautiful experiment," says Rum- 

 ford, "was very striking, and the pleasure it afforded 

 me amply repaid me for all the trouble I had had in 

 contriving and arranging the complicated machinery 

 used in making it. The cylinder, revolving at the rate 

 of thirty-two times in a minute, had been 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, and it was not long 

 before the water which surrounded the cylinder began 

 to be sensibly warm. 



" At the end of one hour I found, by plunging a ther- 

 mometer into the box, . . . that its temperature had 

 been raised no less than forty-seven degrees Fahrenheit, 



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