kprcmc MEAT OK CASKS. 
if'O 
Tl>e following is the result of two coinpnraiive expcrixents 
ade on the air at two different pressures. 
Acurrent of atmospheric air of 35'9(il litres in ten minutes, 
ider a pressure of I '0058 metres of mercury, in coohng from 
1°41.5, afforded a quantify of heat sufficient to support the 
mperature of the calorimeter to a term more elevated' by 
J J'03, than that in which it had been maintained without this 
irrent, 
Lut the same current of air under the pressure of0 740.‘3, 
;her circumstances being the same, supported the temperature 
F the calorimeter only 15^423 above that of the ambient air: 
le proportion of these two numbers may therefore be taken for 
leir specific heats. 
These two comparative experiments, repeated with great care, 
ive us, after having made all the calculations with resp<*ct to 
le specific heat of the air, subjected to a pressure of ()m.7405, 
id that of ihe air subjected to a pressure of lm.0059, that of 
: l-26(i5. 
Taking the medium between the two results, we find that, 
he specific heat of the air, (at the pressure of 0 7*fOj) 
sing 1 0000 - - fOOOO 
hat of the same volume of air. 
It the pressure of 1 0058) is - r2396 and the same 
’ weight - 0 0126 
If we suppose, that the differences between the pressures are 
roportional tp the differences between the specific correspon- 
;int heats, we may, by means of the preceding results, re- 
ice by calculation, the specific heat of the air taken under 
iHie pressure, to what it would be under a different pressure, 
i ut as it is clear, that the suggestion we here announce ap- 
rroaches nearly to the truth, and is applicable to all the gases, 
follows, that the differences between the pressures must be 
■ery small ; this induces us to believe, that we have not made 
ray sensible error in applying, in the preceding tables, a cor- 
Mclion founded on these principles. 
Sec- 
