

Mr Barlow on the Developement of Magnetism, <S?c. %65 



enemies reach the spot, to seize and destroy all they can. 

 The trees are felled, and are made to fall in such a way, that 

 the cutting of one causes the fall of one or two more, or shakes 

 others in such a manner, that the squabs or young pigeons 

 are violently hurried to the ground. Their tender juicy flesh 

 is no great trial, it may be supposed, to man's compassion, and 

 the poor birds are eaten up under the eye of their fluttering 

 parents, without any pangs of remorse. 



Art. XIX. — On the Developement of Magnetism by Rotation, 

 in reply to Mr Christie. By P. Barlow, Esq. F. R. S. 

 Mem. Imp. Ac. Petrop. &c. Communicated by the Author. 



Dear Sir, 

 As I am equally anxious with Mr Christie to put a stop to 

 the correspondence so unnecessarily begun in your Journal, 

 I shall content myself by replying principally to his remark 

 respecting the authorship of the historical sketch. On this 

 head I beg to state that, with the exception pointed out in 

 my former letter, I wish him to consider me responsible for 

 the accuracy of the several points to which he has thought 

 proper to object ; but, at the same time, it is right that I 

 should say I am not the author of the entire paper in the form 

 in which it appears in your Journal. I think it necessary to 

 state this, because I feel, that, however unintentionally, too 

 much credit is given in that article to the English experiments, 

 as contrasted with those of the French. I have certainly al- 

 ways considered M. Arago's experiments as an entire and dis- 

 tinct series ; developing a beautiful and independent system 

 of forces, neither suggested by, nor derivable from, any experi- 

 ments made in England ; that the results obtained by the ra- 

 pid rotation of the iron shell form an important link in this 

 chain of phenomena I am willing to believe ; but it was alto- 

 gether accidental that both facts should have been observed 

 so nearly at the same time. 



Having said thus much, I am quite content to leave what- 

 ever may be in dispute between Mr Christie and myself to be 

 judged of from what has been already stated. Mr Christie 

 conceives that the experiments he undertook in 1821, and which 



