﻿432 Prof. J. Bayma on the Fundamental 



represent the three states of bodies by conceiving the molecules of a 

 gas to be in such a condition that, if it were entirely freed from 

 pressure, it would expand into a liquid. We know that many gases 

 can be compressed into a liquid, but it is altogether gratuitous to 

 suppose that they could be brought into a similar condition by a di- 

 minution of pressure. Experiment has given no indication of such 

 a result or tendency." 



This is a mistake. My curve of molecular action does not 

 require the molecules of a gas to be in such a condition that, if 

 entirely freed from pressure, it would expand into a liquid. 

 What I said is this. " If hydrogen, or any other gas, were freed 

 from pressure, it would expand as much as its constitution re- 

 quires, viz. to a certain determinate bulk only ; for there must 

 be a limit of expansivity for all permanent substances. Then 

 it would remain at rest in the same manner as if it were a liquid. 

 Its molecules would then be at the distance of equilibrium : and 

 its difference from known liquids would only be that, whilst 

 other liquids do not allow themselves to be sensibly reduced in 

 bulk, hydrogen would allow of a very sensible reduction" (Mo- 

 lecular Mechanics, p. 195). Such is my real doctrine. But 

 Professor Norton seems to have thought that a thing, which can 

 remain at rest in the same manner as if it were a liquid, must 

 needs be a liquid : and it is on the strength of such a brilliant 

 discovery that he proceeded to pronounce that I have " certainly 

 failed" in this first of several "important" points. 



But, again, my curve of molecular action in his judgment 

 "cannot represent the three states of bodies," unless the 

 gaseous molecules are of the condition already described. I 

 reply that my curve of molecular action has been drawn from 

 the consideration of bodies in general, without descending to 

 those special conditions which must be verified in the case of 

 gases. Hence Professor Norton is perfectly free to remove, 

 even indefinitely if he likes, the intersection of the curve with 

 the axis, viz. the point where repulsion ceases and attraction 

 begins. In this case the actions represented by the ordinates 

 of the curve will easily become repulsive all throughout to his 

 full satisfaction : only it might be difficult, after this change, 

 to say what body in nature we could point out as possessing 

 the properties indicated by the curve so boldly stripped of its 

 inferior branch. 



As for 'the limit of expansivity of the gaseous molecules, its 

 necessity is not gathered from the curve of molecular action, nor 

 from the nature of the gaseous state, but from the permanency 

 of the gaseous substance. That it is not deduced from the 

 curve of molecular action is quite evident — since the curve is 

 only the expression of facts already established, and represents 



