424 Intelligence and Miscellaneous Articles. ' 



ON THE THERMAL BEHAVIOUR OF LIQUIDS. 

 BY P. DE HEEN. 



To the Editors of the Philosophical Magazine. 



Gentlemen", 



In the February number of this Journal Messrs. Ramsay and 

 Young have published a note on the critical temperature in which 

 a statement appears of which, in the interests of science, I am 

 compelled to ask them for an explanation ; they have characterized 

 as "very inaccurate" a paper on the same subject by myself*. 

 This would not be of much importance if my work had not attracted 

 the attention of many physicists and especially of M. Galitzine, 

 who would thus have been led into error by my mistake. 



To avoid this I venture respectfully to request Profs. Rainsay 

 and Young to point out the errors of reasoning and of experiment- 

 ation that I have made in the demonstration of my fundamental 

 proposition : — " The volume of a fluid is not always defined by the 

 temperature and pressure only;" thus fluids of different density can 

 correspond to the same temperature and pressure. On this pro- 

 position all my deductions rest. 



It would also be of service to show the error committed by 

 M. Galitzine in his demonstration. 



I may also point out to Profs. Earn say and Young that before 

 1880 I had arrived at the conclusion that the particles that con- 

 stitute liquids have a different volume from the particles of vapour. 

 It was by this means that I explained the maximum density of 

 water f . 



Profs. Eamsay and Young think with M. Gouy that the only 

 variation of density produced in liquids confined in a tube results 

 from the variation of hydrostatical pressure ; the great compres- 

 sibility of fluids near the critical point would cause very con- 

 siderable variations of density. The ingenious interpretation of 

 M. Gouy, which would explain very simply an anomaly that at first 

 had a paradoxical appearance, cannot now unhappily be admitted. 

 If it were correct there should be produced immediately, at the 

 critical temperature, a stable equipoise in a pipe vertically fixed. 

 The experiments I published last year show that this is not the 

 case ; thus the mode of distribution of substance is different a 

 little after the disappearance of the meniscus and twenty-four 

 hours after J. 



P. De Heen. 



* " Sur un £tat de la matiere caracte'rise par 1'independance de la pres- 

 sion et du volume specifique," Bulletin deV Acad. Roy. de Belgique, t. xxiv. 

 for 1892. 



f " De la dilatabilite de quelques liquides organiques et des solutions 

 salines," presents a VAcad. Roy. de Belyique, May 6, 1879. 



% " De l'influence du temps sur le mode de formation du me"nisque a 

 la temperature de transformation/' Bull, de VAcad. Roi/. de Belyique [3] 

 xxv. p. 14 (1893). 



