214 THE POPULAR SCIENCE MONTHLY. 



The total quantity of heat generated may be estimated with some 

 considerable degree of precision as follows : QuantUy of ice coM 



water which, with 

 the given quantity 



" Of the heat excited there appears to have been actually of heat, mignt have 



* been heated 180, or 



accumulated : made to boil. 



" In the water contained in the wooden box, 18 pounds, In avoirdupois weight, 

 avoirdupois, heated 150, namely, from 60 to 100 Fahr. . . . 15.2 



"In 113.13 pounds of gun-metal (the hollow cylinder), heated 150 ; 

 and, as the capacity for heat of this metal is to that of water as 0.1100 to 

 1.0000, this quantity of heat would have heated 12| pounds of water the 

 same number of degrees .......... 10.37 



" In 36.75 cubic inches of iron (being that part of the iron bar to which 

 the borer was fixed which entered the box), heated 150 ; which may be 

 reckoned equal in capacity for heat to 1.21 pound of water . . .1.01 



" 1ST. B. No estimate is here made of the heat accumulated in the 

 wooden box, nor of that dispersed during the experiment. 



" Total quantity of ice-cold water which, with the heat actually gen- 

 erated by friction, and accumulated in two hours and thirty minutes, 



might have been heated 180, or made to boil 26.58 



" As the machinery used in this experiment could easily be carried round 

 by the force of one horse (though, to render the work lighter, two horses were 

 actually employed in doing it), these computations show further how large a 

 quantity of heat might be produced, by proper mechanical contrivance, merely 

 by the strength of a horse, without either fire, light, combustion, or chemical 

 decomposition ; and, in a case of necessity, the heat thus produced might be used 

 in cooking victuals. 



"But no circumstances can be imagined in which this method of procuring 

 heat would not be disadvantageous ; for more heat might be obtained by using 

 the fodder necessary for the support of a horse as fuel. . . . 



" By meditating on the results of all these experiments, we are naturally 

 brought to that great question which has so often been the subject of specula- 

 tion among philosophers, namely : 



" What is heat ? Is there any such thing as an igneous fluid ? Is there any- 

 thing that can with propriety be called caloric ? 



"We have seen that a very considerable quantity of heat may be excited in 

 the friction of two metallic surfaces, and given off in a constant stream or flux 

 in all directions without interruption or intermission, and without any signs of 

 diminution or exhaustion. 



" Whence came the heat which was continually given off in this manner 

 in the foregoing experiments? Was it furnished by the small particles of 

 metal, detached from the larger solid masses, on their being rubbed together ? 

 This, as we have already seen, could not possibly have been the case. 



" Was it furnished by the air? This could not have been the case; for, in 

 three of the experiments, the machinery being kept immersed in water, the ac- 

 cess of the air of the atmosphere was completely prevented. 



"Was it furnished by the water which surrounded the machinery ? That 

 this could not have been the case is evident: 1. Because this water was con- 

 tinually receiving heat from the machinery, and could not at the same time be 

 giving to and receiving Tieatfrom the same body ; and, 2. Because there was no 

 chemical decomposition of any part of this water. Had any such decomposition 

 taken place (which, indeed, could not reasonably have been expected), one of its 



