QUANTITY OF HEAT. SPECIFIC HEAT. 



The substance to be experimented on was broken in pieces, and 

 placed in a little metal basket hung in the steam-jacketed chamber 

 A, placed on a box B. A was closed above by a cork, through which 

 passed the thread supporting the basket, and a thermometer with its 

 bulb close to the basket, so as to indicate the temperature of the 

 contents. The steam was admitted at I and taken out at O. Below, 

 the chamber was closed by a trap-door T, in the top of the supporting 

 box. Steam was passed through the jacket surrounding A for one 

 or two hours, so that the substance was at the temperature of the 

 steam. The side D of the box was prolonged upwards to screen 

 the steam-chamber from the calorimeter. A trap door moving verti- 

 cally in this side 

 was drawn up 

 when the sub- 

 stance was suffi- 

 ciently heated, 

 and the calori- 

 meter was 

 pushed in so as 

 come immediately 

 under A; the trap- 

 door beneath A 

 was opened, the 

 thread cut, and 

 the basket 

 dropped into the 

 calorimeter. The 

 calorimeter was 

 then withdrawn, 

 and the door in 

 D at once shut 

 down. The rise 

 in temperature of 

 the calorimeter 

 could then be 

 noted, and by 

 subsequent obser- 

 vations the loss of 

 heat to the sur- 

 roundings could FlG. 54. Kegnault's Apparatus for Determination of Specific 

 be determined Heat of Liquids by Method of Mixtures, 



and allowed for. 



The capacity of the basket was, of course, found by subsidiary experi- 

 ments, and the heat which it gave to the calorimeter was subtracted. 



Experiments on Liquids. One form of apparatus which Regnault used 

 to determine the specific heat of liquids is represented in Fig. 54. The 

 actual mixture of the liquid with water was not permissible in many 

 cases, and therefore a thin metal vessel was fixed within the calori 

 meter. Into this the liquid was poured, and ultimately it came to 

 temperature equilibrium with the water in the calorimeter. Virtually, 

 then, the method may be described as one of " mixture." The liquid 



