244 Description of M. Mont golfer' s Calorimeter. 



ployed are compared with each other and valued at a mean 

 price, it will be easily seen what effect the one has in com- 

 parison with the other, and consequently what species of 

 fuel is the most ceconomical and cheapest. 



We may observe further, that the pipe m may be made 

 of wood ; but if it is of plate-iron or copper, it must be 

 surrounded with severaj coatings of paper, by which means 

 less heat will be lost. 



The pipes k, k, and m, m, may be lengthened at pleasure, 

 because still a good deal of caloric escapes by the aperture I. 



This apparatus may be applied to various purposes ; such 

 as boiling water at a small expense. It is of great utility in 

 domestic ceconomy. To render its effect as complete a3 

 possible, the smoke, or rather the burnt air, should be de- 

 prived as much as possible of its caloric, which ought to be 

 employed entirely in gradually increasing the temperature of 

 the water surrounding the chimney. This air, thus cooled, 

 being heavier than that of the atmosphere, determines in 

 the furnace the current of air; an effect which is not ob- 

 tained in ascending chimneys but by sacrificing a very con- 

 siderable quantity of caloric. It is consequently advisable 

 to lengthen the chimney as much as the height of the apart- 

 ment permits *. 



* We very much suspect that this apparatus has never been tried ; for, in 

 the way prescribed for conducting the experiments, it would be difficult to 

 obtain the same results twice from the same kind of fuel. Even in an open 

 grate it would be no easy matter to find out means by which to make a fiie 

 of wood, of coal, or of turf, always burn up in t^e same time and with the 

 fame degree of force in the seme time. The difficulty, nay, the impossibility, 

 of always laying the fuel and igniting it in such a manner that all'the circum- 

 stances shall be precisely the same, renders it very improbable that results 

 should ever be obtained that could be at all depended on, by following the 

 means pointed out. Still, however, we think the instrument, or something 

 similar, might be so employed as to give useful results — not by such short 

 experiments as are proposed in the above paper, but by carrying on the 

 trials with each of the different kinds of fuel for a day or two, and ascertain- 

 ing how much water a given weight of each of them could evaporate, and, 

 noting the times. — Edit. 



XXXVIII. Che- 



