Mr Christie on the Magnetism of Iron in Rotation. 15 



as far as iron is concerned. It is certainly very unpleasant to 

 my feelings to make this statement ; but as you have, very er- 

 roneously I have no doubt, stated in your Journal that it was 

 for his " discoveries respecting the effects of rotation on the 

 magnetic forces," * that the Copley medal was adjudged to 

 Mr Barlow, you must allow that I am called upon to do so in 

 justice towards myself. 



As it was considered that Mr Barlow's experiments natu- 

 rally arose out of those which I had so long before communi- 

 cated to him, it was agreed between us, that his paper should 

 not be presented to the Royal Society till after mine ; and 

 your correspondent is perfectly correct in stating, that the 

 publication of Mr Barlow's was, in consequence, delayed un- 

 til May, although I must acknowledge I am at a loss to con- 

 jecture whence he derived his information. Although this 

 arrangement was rendered nugatory by Mr Barlow's publish- 

 ing an account of his experiments in the Edinburgh Philoso- 

 phical Journal for July last, I feel fully convinced that it 

 must have entirely proceeded from an oversight, that he al- 

 lowed the publication to take place so long before the appear- 

 ance of the paper in which these experiments are detailed 

 in the Transactions of the Royal Society ; and I likewise am 

 persuaded, that he could have no intention of laying claim to 

 the discovery of the influence which rotation has on the mag- 

 netism of iron, — although this early publication of his experi- 

 ments, without the most distant reference to mine, has cer- 

 tainly such an appearance. 



You will easily imagine, that, to enter into the preceding 

 detail, must have been extremely repugnant to my feelings ; 



• The Editor must take to himself the whole hlame of any error in 

 this notice. As the Copley medal was always understood to be ad- 

 judged for the best paper in the Transactions during the year, and as Mr 

 Barlow's paper on the magnetism of rotation, was the only one he publish- 

 ed in the Transactions for 1825, we never doubted that the Copley medal 

 was given for the discoveries contained in that paper. This idea was con- 

 firmed by the adjudication of another medal to M. Arago, which led to 

 the belief that these two gentlemen thus divided the honour which at- 

 taclied to the discovery of the influence of rotation on the magnetic forces. 

 IMr Barlow's discovery of the neutralizing plate, having been made long 

 ago, we never supposed that the medal had any reference to it. — Ed. 



