242 Description and Maimer of using 



M. Montgolfier, to whom we are already indebted fut 

 many useful discoveries, has put an end to all difficulties 

 upon the above subject, by the invention of an apparatus 

 to which he has given the name of a calorimeter *. 



Description of tlte Calorimeter. 



Plate V. represents a section of the above apparatus. 



A, B, C, D, is a case of tinned iron (if made of wood 

 it would be more ceconomical and advantageous) which must 

 be so well joined that no water may be permitted to escape ; 

 it has a cover A, B, through which is made an aperture a, b ; 

 in the bottom also is an aperture e,f. 



The small stove a, l>, c, d, e, f, is made of plate iron or 

 copper, having its joinings carefully closed that it may not 

 admit of any of the water getting in. Its lower aperture 

 corresponds with that of the case e, f ; another aperture in 

 the upper part is closed near a, I, by a plug, which may be 

 taken out at pleasure. 



c, d, is a grate composed of iron wire upon which the 

 combustible is placed ; the ashes fall down from the 

 grate by the aperture g. 



Near h, i, a pipe k, k, is adapted for giving a passage to 

 the smoke which escapes by the aperture /. This pipe 

 ought to be made of plate-iron or copper, and so close as 

 not to permit the water which surrounds it to penetrate it. 



m, m, is a pipe of plale-iron larger than the former and 

 which surrounds it, so that the water is kept between both. 



E is the reservoir, of which the covering r, s, may be taken 

 off to fill the apparatus with water. 



o, o, is a pipe which comes from the same reservoir, and 

 which communicates with the pipe m, m. 



p, is a cock to let out the boiling water ; and q, is an- 

 other cock, by means of which we may empty the appara- 

 tus if necessary. 



F. G. are the feet upon which the apparatus rests. 



* This apparatus differs essentially from the calorimeter proper for chemi- 

 cal experiments invented by Messrs. Lavoisier and La Place. 



Method 



