Large ^atithy of Water made U boil by Fri^ion. 1 13 



When 30 minutes more had elapfed, or i hour and 30 minutes after the machinery had 

 been put in motion, the heat of the water in the box was found to be raifedto 178". 



At 2 hours '20 minutes, it was at 200°; and at 2 hours 30 minutes it actuallt . 



BOILED. 



It would be difficult to defcribe the furprife and aftoniflimcnt cxprefled in the counte- 

 nances of the byftanders, on feeing fo large a quantity of cold water heated, and adually 

 made to boil, without any fire. 



Though there was, in faft, nothing that could juftly be confidered as furprifing in this 

 event, yet I acknowledge, fairly, that it afforded me a degree of childifh pleafure, which, 

 were I ambitious of the reputation of a grave phtlofophery I ought moft certainly rather to 

 hide than difcover. 



The quantity of heat excited and accumulated in this experiment was very confiderable ; 

 for, not only the water in the box, but alfo the box itfelf, (which weighed is^lb.) and 

 the hollow metallic cylinder, and that part of the iron bar which, being fituated within the 

 cavity of the box, was immerfed in the water, were heated through 150 degrees of Fahren- 

 heit's fcale; viz. from 60 degrees (which was the temperature of the water and of the ma- 

 chinery at the beginning of the experiment) to 210 degrees, the heat of boiling water 

 at Munich. 



The total quantity of heat generated may be eftimated with fome confiderable degree of 

 precifion as follows : 



Of the heat excited there appears to have been adtually accumu- Quamity of ke-coM waicr 



which, with the given (juantrty 

 lated, °f heat, might have been heat- 



ed to 180°, or made to boil. 



In the water contained in the wooden box, 1 8 ^Ib. avoirdupois, " voir upoiaweig t. 



heated 1 50 degrees; namely, from 60° to 210° F. - - 15.2 



In 113.131b. of gun metal (the hollow cylinder) heated 150 de- 

 grees ; and, as the capacity for heat of tliis metal is to that of wa- 

 ter as 0.1 1 00 to 1. 0000, this quantity of heat would have heated 

 I2ilb. of water the fame number of degrees. - - 'O.jjr 



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 

 degrees ; which may be reckoned equal in capacity for heat to 

 1.2 lib. of water. _ _ _ . - i,or 



N. B. No eftimate is here made of the heat accumulated in the 

 wooden box, nor of that difperfed during the experiment. 



Total quantity of ice-cold water which, with the heat atlually 

 generated by fridtion, and accumulated in 2 hours 30 minutes, might ■ 



have been heated 1 80 degrees, or made to boil. - - 26.58 



From the knowledge of the quantity of heat aftualiy produced in the foregoing experi- 

 ment, and of the time in which it was generated, we are enabled to afcertain the velocity of 

 its produBioriy and to determine how large a fire mud have been made, or how much fuel 



Vol. II.— June 1798. Q^ mu 



