the Heat excited by Friction. 473 



by them should be sufficiently great to account for all 

 the Heat produced. 



But no such change had taken place; for I found, upon 

 taking equal quantities, by weight, of these chips, and of 

 thin slips of the same block of metal separated by means 

 of a fine saw, and putting them at the same temperature 

 (that of boiling water) into equal quantities of cold wa- 

 ter (that is to say, at the temperature of 59! F.), 

 the portion of water into which the chips were put was 

 not, to all appearance, heated either less or more than 

 the other portion in which the slips of metal were put. 



This experiment being repeated several times, the re- 

 sults were always so nearly the same that I could not 

 determine whether any, or what change had been pro- 

 duced in the metal, in regard to its capacity for Heat, by 

 being reduced to chips by the borer.* 



From hence it is evident that the Heat produced could 

 not possibly have been furnished at the expence of the 



* As these experiments are important, it may perhaps be agreeable to the Society to 

 be made acquainted with them in their details. 



One of them was as follows : 



To 4590 grains of water, at the temperature of 59^ F. (an allowance as compen- 

 sation, reckoned in water, for the capacity for Heat of the containing cylindrical tin 

 vessel being included), were added 1016^ grains of gun-metal in thin slips, separated 

 from the gun by means of a fine saw, being at the temperature of aio F. When 

 they had remained together I minute, and had been well stirred about, by means of a 

 small rod of light wood, the Heat of the mixture was found to be = 63. 



From this experiment the specific Heat of the metal, calculated according to the 

 rule given by Dr. Crawford, turns out to be = O.I 100, that of water being= i.oooo. 



An experiment was afterwards made with the metallic chips as follows : 



To the same quantity of water as was used in the experiment above mentioned, at 

 the same temperature (viz. 593), and in the same cylindrical tin vessel, were now 

 put ioi6 grains of metallic chips of gun-metal bored out of the same gun from 

 which the slips used in the foregoing experiment were taken, and at the same temper- 

 ature (210). The Heat of the mixture at the end of I minute was just 63, as be- 

 fore; consequently the specific Heat of these metallic chips was=o.noo. Each 

 of the above experiments was repeated three times, and always with nearly the same 

 results. 



