[ 438 ] 



XLV. Note on some Thermal Properties of a Mixture of Car- 

 bonic Acid and Nitrogen. By K. Tsuruta, Rigakushi, Tokio, 

 Japan *. 



LlTEKATUEE. 



IN his classical researches on thermal properties of carbonic 

 acid, Andrews found the isothermals for 13°*1 and 21°*5 a 

 little rounded-off at the points of complete liquefaction and of 

 complete evaporation, and pointed out that this was due to a 

 very small unavoidable admixture of air in the gas. Maxwell 

 was much interested in this "question, of an exceedingly 

 interesting nature," as appears from his letters to Andrews f . 

 Andrews then made a further investigation on the subject, 

 the results of which were given in an abstract J. A further 

 account was published as a posthumous paper in the ' Philoso- 

 phical Transactions ' for 1886 §. 



The subject did not remain unattacked by other physicists 

 working in this part of the field of investigation. Oailletet 1[ 

 made some experiments as early as 1880 on mixtures of car- 

 bonic acid and other gases, on which Jamin wrote a note **. 

 In England, Ansdell was occupied with various mixtures of 

 hydrochloric acid and carbonic acid ff. 



Cailletet studied especially the very curious fact of the 

 appearance and disappearance of the condensed state at 

 certain temperatures and pressures ; Ansdell confined his 

 attention to the determinations of the critical temperatures of 

 the mixtures ; while Dewar described many interesting facts 

 relating to the behaviour of carbonic acid in presence of 

 other substances J +. Andrews's paper contains a series of 

 measurements on changes of volumes,, pressures, and tem- 

 peratures of the mixture of carbonic acid and nitrogen in the 

 proportion of 3 to 4. Thus, although the paper was pub- 

 lished, according to Prof. Tait, twelve years after the date of 

 experiment, yet it has remained, and still remains, so far as 

 I am aware, a very complete investigation and perhaps the 

 only one. 



* Communicated by the Author. 



t The Memoir on the Life of T. Andrews, bv Tait and Brown, 

 pp. 14-15. 



X ' The Scientific Papers of T. Andrews,' pp. 383-392. 



§ Ibid. pp. 457-471. 



«f[ Journ. de Phys. torn. ix. (1880). 

 ** Comptes Kendus, xcvi. (1883). 

 ft Proc. Roy. Soc. vol. xxxiv. (1882). 

 ft Ibid. vol. xxx. (1880). 



