> ia 
On the Rayid Production of Steam. ~ 315 
If tee apetatae assumed for comparison be preci 
above 212° as is equal to the number of degrees of he 
come latent in water while it passes in into steam, it is evi 
substance at comparable temperature, cand possessing the sa 
“cific heat as pater, would generate its own ne of steam in co 
down 
i 
metal. Specific heat. 
- x .1100 ‘ae & Dulong. 
0949 
spat 4100) Dalton, 
Pe 4 0557 Eas ge Dulengs: 
36 “ 
It must be ae that the above stat : Basccibe cae 2 
taken from Petit and Dulong, are those of the mean effect from 0° 
to ag centigrade. ‘That of silver, for example, is .0557 within 
these limits, but if the mean specific heat found by from 1° to | 
300° cent. be adopted it will come somewhat ore the result of 
iy experiments, that is .0611. 
‘The method which has thus been adenest adds another to the 
means heretofore employed for determining the specific heat of many 
solid and gaseous substances, or at least of verifying the results of 
former methods. The three modes, just alluded to, are those of 
‘mixture, of melting ice, and of cooling in air, the last in particular 
Seems liable to many objections on account of the different conduct- 
ing and radiating power of the bodies, and the different natures of 
surface which may be given to each, whereby the time of cooling, 
Which is made the measure, will be exceedingly variable. 
The calorimeter, of Lavoisier, is not regarded as correct in its 
indications, on account of the subsequent congelation of a portion 
of the j ms melted by the hot body, and the rise of temperature in 
ot 
