Heats with Temperature and Density. 535 



The two sets o£ results are unfortunately inconsistent, 

 and no conclusion can be drawn from them. 



jS. Lussana * finds that for air " C^ with the pressure 

 increases; it reaches a maximum, and then decreases/'' This, 

 as far it goes, confirms the results obtained for ether. 



(3) Carbon Dioxide. 



E. H. Amagatf obtaining C« from Joly's empirical 

 formulae, calculated 7 for C0 2 by means of the equation 



a+T U f UbtJ 



y= p •• 



The conclusions at which he arrives confirm the results 

 shown in figs. 1 and 3. He says that for C0 2 : 



"7 doit aussi passer par un maximum peu eloigne des 

 limites du Tableau. ... A une temperature plus 

 rapprochee de la temperature critique ces variations 

 seraient encore plus prononcees. . . . Au contraire, a 

 des temperatures de plus en plus elevees, ces variations 

 s'affaiblissent graduellement et le maximum par lequel 

 passent les valeurs de 7 finirait par disparaitre.'"' 



S. Lussana J gives the following results for C0 2 : — 



(1) With increasing pressure C p increases with the 

 pressure less rapidly at low temperatures than at 

 high ; and 



(2) At atmospheric pressure C p increases with increasing 



temperature ; but, with increasing pressure, it is 

 very soon greater for lower temperatures than for 

 higher ; 



and in a further communication § he finds agreement between 



his results and those deduced by Amagat. 



With the exception of the irregular behaviour of C P at 



atmospheric pressure observed by Lussana, his results afford 



further confirmation of the results deduced from the equation 



of state. 



University College, Dundee, 

 February 1907- 



* S. Lussana, Beibl Bd. xxiii. p. 245 (1899). 

 f E. H. Amagat, C. R. cxxi. pp. 863-6 (1895). 

 % S. Lussana, 'Beibl Bd. xx. pp. 522-3 (1896). 

 § S. Lussana, Beibl. Bd. xxii. pp. 548-9 (1898). 



