M. Monlgolfier's Calorimeter. .243 



Method of using the Calorimeter. 

 When it is necessary to determine the length of time 

 which various combustibles require to extricate a given 

 quantity of teat, the reservoir E is filled with water, which 

 passes through the pipe o, o, ascends into the pipe vi, m, 

 and penetrates by the pipe v., n, into the case A.B. C. D. 

 As much water is poured in as will fill the whole of the case, 

 and when full it maybe easily seen by the water not descend- 

 ing below the line /, u, which is the highest point of the water 

 in the apparatus, and its temperature is observed by means 

 of a thermometer. A sufficient quantity of the combustible 

 to be used in the experiment, for instance, wood, cut into 

 small pieces, is then placed upon the grate c, d : after bav- 

 ins; lighted it up, the upper opening Gf the stove a, I, is 

 closed with the stepper, and it must then be noticed how 

 lono time it requires before the water arrives- at a certain de- 

 gree of heat (the boiling point for instance), and which may 

 be ascertained with the thermometer. The fire rs then with- 

 drawn, and the water as well as the stove are allowed to cool 

 until they return to the temperature at which the operation 

 was commenced. Another kind of combustible, suppose coal 

 or turf, may be then placed on the grate, and the apparatus 

 managed as before, after the fire being lighted up, 



We can ascertain the greater or less promptitude with 

 which heat is extricated from the combustible, by comparing 

 •the length of time which the two experiments required. 



To find the difference of the quantity or weight of com- 

 bustibles of different kinds proper for producing this tempe- 

 rature, it is necessary to take a sufiicient quantity of one of 

 the combustibles, suppose a cubic foot of wood ior ex- 

 ample ; — it is lighted up in the stove after the apparatus is 

 filled with water, and its temperature marked. The thermo- 

 meter determines the moment when the water is in ebulli- 

 tion. The fire is then extinguished, and all the combustible 

 remaining in the grate is taken away; and when the appa- 

 ratus has returned to the first temperature, any other com- 

 bustible may be treated in the same mariner. 



|| after the operation the quantities of combustibles cm- 

 ( ) -2 ployed 



