THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



SEPTEMBER 1880. 



XXIII. On the Behaviour of Liquids and Gases near their 

 Critical Temperatures. By J. W. Clark*. 



[Plate III.] 



IN 1822 Baron Caignard de la Tour f showed that the offects 

 of heat on a liquid enclosed in a vessel adapted to the 

 purpose, was to convert it into vapour at a volume a little 

 more than twice that which it originally possessed. Within 

 a certain limit he found the temperature at which this change 

 occurred was independent of the ratio existing between the 

 volume of the liquid and that of the tube, but above that limit 

 the conversion was first observed at a higher temperature. 

 Brtinner t, after an extensive discussion of previous memoirs, 

 states the results of his observations upon the decrease which 

 heat produced in the height to which water, ether, and olive 

 oil rose in capillary tubes. He experimented at temperatures 

 below 100° 0. In 1857, from Briinner's expression for this 

 decrease in the case of ether, Wolf § calculated the tempera- 

 ture at which the level of the liquid in the capillary tube 

 should coincide with that outside it; and in the attempt to 

 test his conclusion experimentally he found that it sank below 

 the liquid in the external tube. He stated that the surfaces 

 became convex, and that the depression was the result of true 



* Communicated by the Physical Society. 



t Ann. de Chim. et de Phys. t. xxi. p. 127 and p. 178 ; ibid. t. xxii. 

 p. 411. 



\ Pogg. Ann. der Phys. u. der Chemie, Bd. lxx. S. 481. 

 § Ann, de Chem. et de Phys. t. xlix. p. 272. 



Phil. Mag. S, 5, Vol. 10. No, 61. Sept. 1880, M 



