142 Mr. J. A. Fleming on the Polarization of 



his authority upon the main subject in opposition to Mr. Mal- 

 let's would be a begging of the whole question in dispute. But 

 it will be admitted that what was novel to him in his favourite 

 subject could hardly be otherwise than new. I received a letter 

 from him in October last, in which, after expressing his grati- 

 fication that the results of my calculations confirmed his long- 

 held opinions, he added, " There is, however, one of the points 

 you put forward which never struck me before, but which 

 now appears to mo most valuable, namely that the enormous 

 amount of steam that has escaped from the interior in early 

 times as well as down to the present, has been, and is, the 

 cause of those subsidences of the crust, to which the basins of 

 seas and oceans, and the crumplings of the terrestrial rocks 

 are owing, far more than to any general contraction of the 

 nucleus by cooling." 



I would request any person who may happen to read this to 

 correct the following error in my former paper (Phil. Mag. 

 October 1875) :— At p. 316, line 6, insert k; for " 1£ mnV' 

 read " 533 miles," and dele the following line. 



XVIII. On the Polarization of Electrodes in Water free from 

 Air. Bij J. A. Fleming, B.Sc. (Lond.), F.C.S., Science 

 Master in Cheltenham College*, 



IN the 'Electrical News ' for September 2, 1875, 1 published 

 a short paper, previously read at the Meeting of the Bri- 

 tish Association at Bristol, entitled " The Decomposition of an 

 Electrolyte by Magneto-electric Induction." In it experiments 

 were described showing that when an electrolyte (viz. dilute 

 sulphuric acid) flows in a very strong magnetic field, the elec- 

 tromotive force generated by its motion effects the electrolysis 

 of the liquid, such electrolysis being held to be proved by the 

 subsequent polarization of the electrodes. No actual liberation 

 of gases was observed, since the electromotive force brought 

 into play was insufficient to effect free decomposition. At the 

 time it was read Professor H. A. Rowland raised certain 

 doubts as to the correctness of the conclusions drawn ; and his 

 remarks were published, appended to my paper, in the ( Elec- 

 trical News.' As these objections would, if correct, have de- 

 prived the experiments entirely of any little interest they might 

 otherwise have had attaching to them, it was obviously neces- 

 sary to examine them carefully. 



Professor Rowland's remarks amounted practically to saying 

 that he thought the electrolyte was not really decomposed, but 



* Communicated by the Author. 



