Effects due to Magnetization. 479 



and negative ordinates the reverse current. Other experi- 

 ments with fresh solutions, same electrodes, same exposed 

 area, and every condition as nearly as possible the same, gave 

 curves of practically the same character, and the one given is 

 selected to illustrate. 



The curve indicates that the original current was to the 

 point electrode ; this gradually decreased, owing to polarization, 

 until after a hour and five minutes it reversed slightly, but 

 again reversed thirty-five minutes later, and after a little 

 more than two hours the deflexion became perfectly constant, 

 remaining so indefinitely. 



The iron salts formed could not move with facility from the 

 exposed surfaces through the hardened gelatine, and were 

 easily outlined from their brown colour, as the whole appa- 

 ratus was placed in a strong light. 



B. In a Uniform Magnetic Field. 



The cell was next placed in the magnetic field, which was 

 kept practically uniform (about 15,650 H) for three hours, 

 and galvanometer-readings taken as before. 



The electrodes were magnetized before being introduced 

 into the solution, so as io protect the point from the begin- 

 ning. In order to prevent the influence of the rise of 

 temperature due to the heating of the field coils of the 

 electromagnet, the whole cell was packed with cotton-wool 

 between the poles. As Gross and Andrews observed, the 

 temperature effect was small, the solution rising but o, 7 C. 

 in half an hour. 



The curve fig. 1 (II.) shows the results of these observa- 

 tions. It is seen that the original current was, as before, to 

 the point electrode, and about the same in value. This 

 reversed after forty-five minutes, and rapidly increased to 

 approximately twice its original value at the end of one hour 

 and twenty minutes, and, instead of again reversing, remained 

 indefinitely with the point electrode as a zinc. The distri- 

 bution of the iron salts in this case was quite unlike the 

 former. Notwithstanding the gelatine, the powerful magne- 

 tization of the exposed point gradually drew the iron salts 

 from the disk as fast as they were formed, and concentrated 

 them symmetrically about the point, giving the solution in 

 this region an almost black appearance. 



After waiting a sufficient time to be assured that further 

 presence of iron salts would not effect the permanency of the 

 existing electromotive force, the magnetic field was gradually 

 decreased without ever breaking circuit, by increasing the 



