422 The Rev. Professor Kelland's Explanation. 



It is singular enough that M. E. Becquerel's claim for his 

 father's priority in the discovery of the principles upon which 

 my battery is constructed appears from his reply (also pub- 

 lished in the last Number of the Phil. Mag.) to be founded 

 principally upon a similar supposed generation of force at the 

 contact of the two liquids. 



If this be its true origin, I at once allow that there is some 

 foundation for the reclamation ; but at the same time I must 

 repeat that such an idea never occurred to me ; as will be 

 evident to those who will take the trouble to consult my con- 

 secutive papers in the Philosophical Transactions: and I 

 must in that case be content with the somewhat mortifying 

 reflection that I was led to a right result by wrong principles. 



The matter is, however, now fairly before the scientific 

 community, and having corrected M. Becquerel's inadvertent 

 remark about the priority of Professor Grove's experiments, 

 I will promise you to take up no more of your valuable space 

 with the subject. I remain, dear Sir, very truly yours, 



Kings College, Nov. 2, 1842. J. F. Daniell. 



To R. Phillips, Esq., fyc. $?c. 



LXXI V. On certain Arguments adduced in the last Number of 

 the Philosophical Magazine. By the Rev. P. Kelland, 

 M.A., F.R.SS. L. $E., F.C.P.S., ##., Professor of Mathe- 

 matics in the University of Edinburgh, late Fellow and Tutor 

 of Queen's College, Cambridge. 



To Richard Taylor, Esq. 

 My dear Sir, 



THE Philosophical Magazine has this moment reached 

 me, by which I am sorry to see that a misprint, or rather 

 a mis-transcription of my paper in the 6th volume of the Cam- 

 bridge Transactions has led both Mr. Earnshaw and Mr. 

 O'Brien astray. I ought to take the blame of this on myself, 

 and do so ; your readers will find my acknowledgement of it 

 at p. 347 of the last Number of your Journal. The three 

 quantities which Mr. Earnshaw copies in p. 341 are not equal. 

 I supposed the axis of y to be that along which transmission 

 takes place, and ought to have made the first and last ex- 

 pression equal to « 2 , and the middle one to w x 2 ; and so in my 

 own copy it is, but I presume the correction was made with 

 a pen. The equality of these two expressions has been em- 

 ployed by Mr. O'Brien to prove that I do not suppose the 

 axis of y to coincide with the direction of transmission ; and 

 if, in applying the equations I had used these quantities as 

 equal, the argument would have been a strong one. But on 



