Prof. Kelland on Charges of Mr. O'Brien. 347 



symmetry, are also true when the symmetry is disturbed by 

 the action of the particles of matter?" I did. not know even 

 what has to be done on this subject. I spoke of it thus : " It is 

 true I did not succeed in proving that the conditions resulting 

 from such an arrangement are the same as those which de- 

 pend on the [supposition of perfect symmetry. Mr. O'Brien 

 proposes to do this, and if he succeeds, it will, I am sure, be 

 an important step in our theoretical investigations." All that 

 I did and do know on this subject is, that M. Cauchy has ar- 

 rived at the same conclusion ; but, if my memory serves me 

 right, under certain limitations. 



Lastly, the only portion of Mr. O'Brien's paper which I 

 can be said even remotely to have attributed to myself, is 

 that which is contained in the following sentences of Mr. 

 O'Brien's reply. " I have assumed that the particles of aether 

 are acted upon by those of matter; and I have employed the 

 equations of M. Cauchy, viz. 



r = 2 m, &c. 



df 



adapting them to the case of a set of aethereal particles acted 

 on by material." 



" He certainly endeavours, in his * Theory of Heat,' to ac- 

 count for dispersion independently of the hypothesis of finite 

 intervals" of the particles of matter. 



To the former of these Mr. O'Brien adds the observation, 

 " So far as this I lay no claim to originality, nor has Pro- 

 fessor Kelland any right to do so either." Now as regards 

 the laying claim, to the process, your readers will be so kind as 

 to refer to my paper and judge for themselves whether or not 

 I have spoken modestly ; and as regards the right, I certainly 

 did believe, and do so still, that it was due to me. At any rate 

 it was incumbent on him who made the charge to have fur- 

 nished the proof. 



I think I have said enough to clear myself from any im- 

 putation of dishonesty. I may add, that my remarks were 

 written in defence of a theory to which I had contributed. 

 The express object of my writing was to prepare for further 

 discussion on the ■possibility of the hypothesis of finite inter- 

 vals. I was therefore constrained to show what I believed to 

 be the state of the theory, and how Mr. O'Brien's hypotheses, 

 &c. differ from it. In doing so, I never combated one of 

 Mr. O'Brien's conclusions, I never disparaged his hypothesis 

 or his mode of accounting for dispersion. Had I erred in any 

 one point, it was Mr. O'Brien's duty to have set me right. 

 He has not done so, unless I am to understand that certain 



Phil. Mag. S. 3. Vol, 21. No. 1 39. Nov. 1 842. 2 A 



