60 Dr. Ritchie's RcmarJcs oil the Papers 



attain pulls another to the same place and secures it in like 

 manner, and so on till he has secured the whole raft, and it 

 will be found that if there be a hundred logs of wood, it will 

 require the strength of a hundred men to prevent their float- 

 ing down the stream. This fact can scarcely be doubted, al- 

 though it is at variance with the Newtonian law, as no force can 

 be supposed capable of generating, under the same circum- 

 stances, a force greater than itself. 



This communication will, I trust, end a controversy from 

 which little more scientific truth can be elicited. 



XV, Remarks o?i two of the Elect7'ic and Magnetic Commu- 

 nications in the last Number of the PhiL Mag. ihjthe. Rev. 

 William Ritchie, LL,D., F.R,S., Professor of Natural 

 Philosophy/ in the Royal Institution of Great Britain and in 

 the University of London,* 



f\^ no branch of science have there been so 7na7uj writers 

 ^^ and so few readers as on that of electricity and magnet- 

 ism. This is fully illustrated by all the papers on that subject 

 in the last Number of the Phil. Mag. (vol. ix. pp. 4-52,469, 472.) 

 The few remarks which I made on Mr. MacGauley's paper, 

 read at the last meeting of the British Association, were re- 

 garded by him as bitter and uncalled-for, though those remarks 

 related only to want of originality of his communication, as the 

 facts had all appeared in print before that period. His last 

 paper in the Phil. Mag. I consider exactly in the same predica- 

 ment. If papers of this kind pass without animadversion, their 

 authors will, at least by the uninitiated, be regarded as the real 

 discoverers of the facts and reasonings contained in them. I 

 feel that in undertaking; the refutation of alleged claims I am 

 undertaking an unpleasant and invidious task. Justice demands 

 it at the hands of some one, and the person best able to do it 

 is mainly concerned ; he has perhaps wisely left it to others. 



The first position claimed by Mr. MacGauley will be found 

 in a paper of mine in the Phil. Mag. for last June, vol. viii. page 

 458. His second position is contained in Dr. Faraday's papers 

 on the length of the coil influencing the spark, and the mutual ac- 

 tion of the spires of the helices. Mr. MacGauley in his third 

 position arrives at the strange conclusion that "magnetism with- 

 in a helix proportionably injures its effect." Dr. Faraday has 

 clearly shown that it is only magnetism in motion that induces 

 electricity. If the soft iron be within a coil which has magnetism 

 induced on it, at the same time that the coil has voltaic elec- 

 tricity induced on it, and if the temporary magnet in returning 

 * Communicated bv the Author. 



