294 E L. Nichols and W. S. Franklin — Electromotive 



of water, only '00002. When potassium chlorate was added to 

 the dilute acid, the effect due to the magnet became very- 

 marked, amounting certainly to several hundredths of a volt ; 

 but the fluctuations in the initial electro-motive force were such 

 as to make readings impossible. In nitric acid diluted with 

 nine parts of water the effect was also very large, but it was so 

 masked by the initial fluctuations described in a previous para- 

 graph, that no quantitative determinations were secured. The 

 strength of field during these experiments was about 10,000 H. 



In the hope of eliminating these fluctuations in the initial 

 electro motive force, two modifications of our apparatus were 

 made. In the first, it was so arranged that a current of the 

 fresh solution passed through both arms of the cell and the 

 products of the reaction were carried away from the neighbor- 

 hood of the terminals almost as soon as formed. In the second 

 modification, terminals were prepared the surface of which con- 

 sisted of pure iron, electrolytically deposited. When these 

 prepared terminals were used, the fluctuations were somewhat 

 less marked than when the original surface of the iron wire was 

 exposed, but the adoption of these two modifications led to no 

 new results. A more important modification consisted in the 

 substitution of platinum or copper for the iron terminal outside 

 of the field. These metals, being unaffected by the magnet, 

 could be placed in close proximity to the magnetized terminal : 

 the internal resistance of the cell was thereby greatly dimin- 

 ished and its form simplified. The iron-copper and iron-plati- 

 num cells were placed between the poles of the electro-magnet, 

 and the investigation consisted in determining the electro-mo- 

 tive force before and after the magnet had been made active. 

 The most satisfactory results were obtained with a cell pat- 

 terned after the Daniell battery — a two-fluid cell in which 

 copper immersed in sulphate of copper was separated from the 

 iron pole by a, porous diaphragm, the iron being submerged in 

 a solution of ferrous sulphate or of ferrous chloride. A cell of 

 this description, in which a neutral solution of ferrous sulphate 

 surrounded the iron, and which possessed an initial electro-mo- 

 tive force of "6072 volts, increased to "6361 volts when placed 

 within the field. Similar results were obtained with other so- 

 lutions. 



In the various forms of apparatus already described the cur- 

 rents due to magnetic action did not always flow in the same 

 direction. The iron terminal within the field would some- 

 times act as zinc toward the unmagnetized. electrode, sometimes 

 as platinum. To determine the law governing the direction of 

 the currents due to the electromotive force of magnetization 

 we tried the following experiments. The terminals of iron 

 wire used in our original apparatus were supplanted by cylin- 



