4,u ExpfrlmentJ on Heat exelK'd by Frt^kn, 



Experiment No. 3. 



A QUADRANGULAR oWong dcal-box, (fee fig. 4.) water-tight, ti{- EriglKh inches long, 

 15/^ inches wide, and 9i\ inches deep, (meafured in the clear,) being provided, with holes 

 or flits in the middle of each of its ends juft large enough to receive the one, the fquarc 

 iron rod to the end of which the blunt fteel borer was faftened, the other, the fmall cylin- 

 drical neck which joined the hollow cylinder to the cannon; when this box (which was 

 occafionally clofed above by a wooden cover or lid moving on hinges) was put into its 

 place -, that is to fay, when by means of the two vertical openings or flits in its two ends, 

 (the upper parts of which openings were occafionally clofed by means of narrow pieces of 

 wood Aiding in vertical grooves,) the box (g, h, i, k, fig. 3.) was fixed to the machinery ia 

 fuch a manner that its bottom ft, i,) being in the plane of the horizon, its axis coincided 

 with the axis of the hollow metallic cylinder ; it is evident from the defcription, that the 

 hollow metallic cylinder would occupy the middle of the box without touching it 011 

 either fide, (as it is reprefented in fig. 3.) and that on pouring water into the box and fill- 

 ing it to the brim, the cylinder would be completely covered and furrounded on every fide 

 by that fluid. And farther, as the box was held faft by the ftrong fquare iron rod (w;), 

 which pafled In a fquare hole in the centre of one of its ends, (a, fig. 4.) 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 leafl; danger of forcing the 

 box out of its place, throwing the water out of it, or deranging any part of the apparatus. 



Every thing being ready, I proceeded to make the experiment I had projeded in the fol- 

 lowing manner : 



The hollow cylinder having been prcvioufly cleaned out, and the infide of its bore wiped' 

 with a clean towel till it was quite dry, the fquare iron bar, with the blunt fteel-borer fixed 

 to the end of it, was put into its place ; the mouth of the bore of the cylinder being clofed 

 at the fame time by means of the circular pifton, through the centre of which the iron bar 

 pafled. 



This being done, the box was put in its place ; and the joinings of the iron rod and of 

 the neck of the cylinder, with the two ends of the box, having been made water-tight by 

 means of collars of oiled leather, the box was filled with cold water, (tIz. at the tempcra- 

 .ture of 60°) and the machine was put in motion. 



The refult of this beautiful experiment was very ftriking, and the pleafure it afi"orded 

 me amply repaid me for all the trouble 1 had had in contriving and managing the compli- 

 cated machinery ufed in making it. 



The cylinder, revolving at the rate of about 32 times in a minute, had been in motion 

 but a (hort time, when I perceived, by putting my hand into the water and touching the 

 outfide of the cylinder, that heat had been generated ; and it was not long before the 

 water which furrounded the cylinder began to be fcnfibly warm. 



At the end of one hour I found, by plunging a thermometer into the wa,ter in the box, 



(the quantity of which fluid amounted to 18.771b. avoirdupois, or 2-^ wine gallons,) that 



Its temperature had been raifed no lefs than 47 degrees, being now 107" of Fahrenheit's 



icale> 



When 



