﻿246 Intelligence and Miscellaneous Articles. 



Ramsay and Young, in the February number of the Philosophical 

 Magazine, on the results obtained by myself and others on the 

 state of matter at the critical point. 



In the first place, the authors observe that there are contradictions 

 between the results arrived at by Galitzine, de Heen, and Zambiasi, 

 and those obtained by myself ; and these contradictions are reduced 

 in the main to the two following : — 



(A) That according to my observations the meniscus disappears 

 during the heating at a temperature higher than the true critical 

 temperature, whilst according to the observations of Galitzine, 

 de Heen, and Zambiasi, the dimness forms during the cooling at a 

 lower temperature than the critical one. 



(B) That Zambiasi and I found that the dimness (or cloudiness) 

 during the cooling process is produced at a lower temperature 

 when the substance contained in the experimenting tube is in a 

 larger quantity, w T hilst de Heen found just the contrary, and 

 Galitzine came to the conclusion that the temperature of the 

 cloudiness is "practicallv independent of the relative quantity of 

 liquid." 



It will be well to examine more closely what are the foundation 

 and value of these contradictions. 



The first does not exist. In fact from the experiments both of 

 Galitzine and myself, in the most favourable conditions the dis- 

 appearance of the meniscus to the last trace of it occurs at a higher 

 temperature than that which one perceives in the ordinary mode 

 of observation, and the disappearance itself takes place at a higher 

 temperature than that at which the cloudiness afterwards takes 

 place. Whilst also it results from my experiments that the 

 cloudiness takes place at a lower temperature than the true critical 

 temperature, in conformity with the result obtained by the other 

 three observers. That Zambiasi found the temperature of the 

 disappearance of the meniscus coincident with that of the cloudi- 

 ness, must certainly be attributed to his mode of observing the 

 temperature. 



In regard to the second point, on the contrary, the difference 

 exists, and therefore merits fresh experiments in order to arrive 

 at a definitive decision. 



I would notice that, in the many observations made by me 

 with several tubes containing various quantities of substance, I 

 had each time a couple of these tubes in identical conditions, and 

 the observation of these tubes was very clear and contemporaneous : 

 therefore it may be that the difference depends on the methods of 

 observation more or less adapted to the end in view, and thus it 

 seems to me that I am right in insisting on my conclusions, which, 

 however, I shall be ready to give up when decisive experiments 

 have settled the question. 



The reasons alleged by Professors Eamsay and Young for de- 

 claring incorrect the experiments in question, which lead to conclu- 

 sions differing from their ideas on the point, are the following : — 



