Intelligence and Miscellaneous Articles, 547 



position of the reversal of all the motions of the universe, when it 

 embraces the whole universe, ourselves included, does not really 

 involve a repetition of the events in reverse order, but only a 

 second way of reviewing the past history of the world. 



These considerations do not seem altogether unfruitful. They 

 emphasize the distinction between true and quasi-dynamical laws, 

 they clear our thoughts with reference to the relation of cause and 

 effect, and, above all, they help to dispel from our minds the 

 prevalent error that time has an existence in itself independently 

 of the particular time-relations that prevail between the thoughts 

 that really occupy our mind, or between events * that actually occur 

 in the universe about us, or between those events and our thoughts. 

 In reality the aggregate of these individual time-relations is the 

 whole of what exists in nature as a background for our conceptions 

 about time. 



ON THE GASEOUS AND LIQUID STATES OF MATTER. 



To the Editors of the Philosophical Magazine and Journal. 



GrENTLEMEtf, 



As a paper recently published by Wroblewski ( Wiener Monatsheft 

 fiir Chemie, 1886, p. 383) is at present being abstracted into other 

 Journals, and as we dissent from every one of his conclusions on 

 the ground that they have no foundation on facts, we beg for per- 

 mission to point out the difference between our views and those 

 expressed in his paper. 



1. "Wroblewski states that lines of equal density (isopyknics) 

 ought never to cut one another. On the contrary, they have been 

 frequently proved experimentally to cut one another during the 

 phenomena of superheated liquid, or "boiling with bumping," and 

 " supersaturated vapour." 



2. The data have been calculated by means of Sarrau's equation, 

 which, although approximately expressing the results, is certainly 

 not true; for the isopyknics should be straight, and not curved. 

 This has been pointed out by Amagat and by ourselves for the 

 gaseous state, and by ourselves for the liquid state. 



3. The vapour-pressure curve is not continuous with the curve 

 expressing the lowest values of p.v, and can hardly be said to be 

 identical with it below the critical point, as the vapour-pressure 

 curve is independent of volume. We have shown that the mini- 

 mum values of p.v lie on the nearly vertical portions of the serpen- 

 tine isothermal lines denoting continuous change from the liquid to 

 the gaseous state. 



4. Sarrau's equation, rigorously applied, involves intersection of 

 the isopyknic lines ; and the author discards it on that account 

 where it no longer bears out his conclusions. "We accept Sarrau's 

 equation as a close approximation to the truth, although not rigo- 

 rously true, and, as such, believe that it correctly represents at any 

 rate the general form of the isothermal curves. 



* Thoughts in other people's minds are some of the events that occur 

 in the universe about us ; that is, in the rest of the universe, excluding 

 ourselves. 



