﻿the Dynamical Theory of Gases. 61 



The aim of my work was not to restate the results of 

 former writers in a new or simplified notation (without, as 

 Mr. Burbury says, "in any way altering the logical position 

 of the Kinetic Theory "). My aim was to give a new dis- 

 cussion of the whole question, based on no physical foun- 

 dations except the laws of dynamics. This I believe to be 

 possible. The molecules of a gas have probably never heard 

 of Mr. Burbury' s Assumption A, or been warned to remain 

 a molekular-ungeordnet." But by passive obedience to the 

 laws of dynamics, they arrange themselves in some definite 

 way. The mathematician, from a knowledge solely of the 

 laws of dynamics, ought to be able to follow the motion of 

 the molecules and calculate their final arrangement. 



This is the problem which I have tried to solve. Mr. Burbury 

 states clearly that he thinks I have failed; while I, to be 

 quite frank, still think I have succeeded. I cannot, therefore, 

 let Mr. Burbury's article pass without reply. 



I do not find that Mr. Burbury brings any new charges 

 against my work, beyond those which he has brought in 

 previous articles*; and to these I have already replied f. 

 1 will confess, however, that I have found a generality and 

 vagueness about these charges, which makes them difficult to 

 refute satisfactorily. If, as Mr. Burbury seems to think, my 

 argument is wholly unsound, he can surely pick out one 

 definite point and say: " Here, at this particular point, you 

 introduce an assumption from outside your premisses"; or, 

 " Here, in this particular statement, your logic is at fault." 

 Or if, as Mr. Burbury perhaps thinks, the number of weak 

 points is legion, I ask him to pick out the weakest one, and 

 concentrate his altack on that — only one link need be broken 

 to destroy a chain. I cannot, within reasonable limits of 

 space, defend a whole theory against vague expressions of 

 opinion, or against a general condemnation, unsupported by 

 specific arguments. 



Meanwhile may I reply to those two of Mr. Burbury's 

 objections, which I understand most clearly ? 



Objection I. " The real defect ... in every proof yet 

 given of Maxwell's Law, consists in my opinion in this, that 

 it ignores the continuity of the motion altogether." 



Answer. Continuity of motion enters most proofs, in- 

 cluding my own attempted proof, through the dynamical 

 equations of motion. In fact, these equations simply express 

 that the continuity assumed by the theory is of the kind 

 observed in nature. 



* Phil. Mag. [6] vi. p. 529; vii. p. 467. 

 t Phil. Mag. [6] vi. p. 720 ; vii. p. 468. 



