Effects due to Magnetization. 445 



liquids. TV hen one electrode was magnetized a current was 

 obtained going in the liquid from the magnetized electrode to 

 the non-magnetized electrode. 



It thus appears that there is at least an apparent inconsist- 

 ency between the protective results of Professor Rowland and 

 Professor Rem sen, and those of Nichols, Andrews, Gross and 

 others, who find the more strongly magnetized parts of iron 

 electrodes more easily attacked than the neutral parts, and it was 

 with the object of endeavoring to reconcile these results, and 

 of studying the exact nature of the influence exerted by the 

 magnet, that the experiments recorded in this paper were 

 undertaken. 



Apparatus and Method of Investigation. 



The method of investigation was that adopted by Professor 

 Rowland in his previous work on the subject, since its facility 

 and delicacy permitted the effects of the magnet to be ob- 

 served whenever there was the slightest action on the elec- 

 trodes by the solution examined, and the investigation could 

 thus be carried over a wide range of material. 



A large electromagnet was employed to furnish the magnetic 

 field, and, at a distance sufficient to prevent any direct influ- 

 ence due to the magnet, a delicate galvanometer of the Row- 

 land type was set up. Small cells were made of iron elec- 

 trodes of special forms, coated with sealing wax, except at 

 certain parts, and immersed in a liquid capable of acting chem- 

 ically on iron. The whole was contained in a 50 cc glass 

 beaker, and when joined to the connecting wires of the distant 

 galvanometer was firmly clamped between the poles of the 

 electromagnet. 



In the course of the examination of a number of substances 

 it was found necessary to use two galvanometers, one specially 

 made by the University instrument maker and very sensitive, 

 which was employed with acids which evolve hydrogen, the 

 other much less sensitive was best suited to the violent 

 "throws" with nitric acid and iron. The samples of iron 

 used throughout the experiments were obtained from Carnegie, 

 Phipps & Co. of Pittsburg, and were practically pure. 



In order to insure a uniform density of surface, the elec- 

 trodes were turned from the same piece and polished equally 

 with fine emery cloth. The magnet could be made or reversed 

 at the galvanometer, and its strength varied at will by a non- 

 inductive resistance. The electro-chemical effects due to the 

 magnetic field could thus be studied with facility by the 

 fluctuations of the galvanometer needle. The original dif- 

 ference of potential which always existed between the elec- 

 trodes was compensated by a fraction of a Daniell cell, so the 



