1813.] Specific Heat of the different Gases. 377 



gases subjected to different pressures are not equal, but differ 

 materially from each other. It is evident also that the ratio 

 between the specific heats is not that of the densities ; for the 

 ratio of the pressures to which the air in these experiments was 

 subjected is 1 : 1'35S3, obviously different from that of the spe- 

 cific heats 1 : l'J396. 



If we attend to the weight, it results, from the same experi- 

 ments, that the specific heat of a mass of air increases with its 

 bulk, without being proportional to it. 



The experiments on the different gases having been made 

 under different pressures, it was necessary, to make them capable 

 of being compared together, to reduce the results to what they 

 would have been supposing them all made under the same 

 pressure. The experiments described in this section furnished 

 us with the means of making this correction ; for since we know 

 that an augmentation of pressure, in the ratio of 1 to 1 '3583, 

 increases the specific heat of the same volume of air in the ratio 

 of I to 1*239.6, we may deduce from these ratios that of the 

 specific heats of two equal volumes of air subjected to pressures 

 of a different ratio from those that have been stated. We may, 

 without running the risk of committing an error of any great 

 importance, employ for that purpose the following propor- 

 tion : (1-3583 — 1 = 0-3583) : (1-2396 — 1 = 0-2396) :: 



( P *"~ * ) : ( 7" — 5 m which D and P denote the two 



different pressures ; r, the known specific heat, corresponding to 

 the pressure P ; and x, the specific heat sought, corresponding 

 to the pressure D. This formula is founded on the supposition 

 that the differences between the specific heals are proportional to 

 the differences of the corresponding pressures, which may be 

 considered as true when the question relates to small differences. 

 We employed the same formula for all the gases, because the 

 law, according to which their specific heats vary according to 

 different pressures, if it be not the same for all, must, at least, 

 be very nearly the same. 



(To b* continued.) 



Article X. 



General Views of the Composition of jlnimal Fluids. By J. 

 Berzelius, M.D. Professor of Chemistry in the College of 

 Medicine at Stockholm. 



(Cuntinuetl frum p. 208.) 



Of Bile. 



It h well known I hat the elder chemists considered the bile as 

 sn animal soap composed of soda and a resin. The accuracy of 



