the developement of Magnetism by Rotation. 217 



tioned the circumstance to him, and in consequence of the 

 analogy between the two series proposed, and I thought it 

 was agreed between us, that he should complete his paper in 

 the form he had intended, and that mine should be delayed 

 till he was ready. Having taken this step, and duly noticed 

 Mr Christie's prior experiments in my memoir, I hoped I had 

 complied with every thing that good fellowship, or the interests 

 of science required, by thus leaving to Mr Christie all the ad- 

 vantages he could have derived from an earlier publication of 

 his experiments. I must say, therefore, that I was rather sur- 

 prised afterwards to find that he had, in this interval, added 

 an appendix to his paper on this new class of rotations, in 

 which no mention whatever is made either of my experiments, 

 or of this arrangement. This omission, and a very injudi- 

 cious remark in one of the reports above alluded to, served to 

 throw a mystery over the subject, and to imply a want of can- 

 dour on one part or the other, which the slight reference that 

 had been made in another part of the paper, was by no means 

 calculated to remove, but which, I conceived, ought to be 

 cleared away. It might therefore easily have been conjectured 

 through whom the information relative to the delay was ob- 

 tained ; and I was pleased to find it had been given exactly as 

 I desired, that is, merely stating the fact, without any refer- 

 ence to the omission alluded to ; and I cannot but wish it had 

 been allowed to pass as it was stated in the report, without 

 rendering this further explanation necessary. 



I have only one other observation to make, relative to Mr 

 Christie's remarks on my correcting plate. It would certainly 

 appear to any general reader, from what is said about the " ne- 

 cessity of some precaution" to prevent the plate revolving, 

 that this precaution had been hitherto omitted, whereas it has 

 never been omitted since the plate has been permanently ap- 

 plied, it having been always necessary to secure it against the 

 motion of the vessel. The precaution, therefore, although in- 

 troduced for another purpose, is always taken ; and it is a little 

 remarkable, that the very first plate I had made in August 

 1819, and which I have still by me, did slide on, as Mr Christie 

 now recommends, the socket and rod being both square ; but 

 I afterwards found it more convenient to make them cylindri- 



