1888.] Electro-chemical Effects on Magnetising Iron. 163 



ments in Division I were with pairs of the small wrought-iron bars, 

 and the observations in Division II were made on pairs of the small 

 steel bars. It will be noticed that the E.M.F. was greater in the case 

 of the wrought-iron than with the steel bars. 



Cupric Sulphate, Col. 13, Divisions I and II, a concentrated solution 

 of the salt in water. The remarks made on the magneto-chemical 

 effects with cnpric chloride apply generally to the reactions obtained 

 with cupric sulphate; it will be noticed, however, that the effect was 

 more extensive when employing the latter salt. 



Gupric Nitrate, Gol. 14, w r as composed of a saturated solution of the 

 salt in water. The magneto-chemical effect was observed with this 

 reagent, though it was more limited in extent than when using either 

 CuCl, CuBr, or CuS0 4 . 



Gupric Acetate, Gol. 15, Divisions I and II. — This was a concentrated 

 solution of the salt in which the effect was small ; but it was dis- 

 tinctly noticeable. 



Gupric Bromide, Col. 16, consisted of a saturated solution of the 

 salt in water. Highly interesting and very marked results were 

 noticed in the experiments with this reagent. The observations in 

 Divisions I and II were made with small rods of wrought iron and 

 steel in apparatus, fig. 4, the results recorded in Divisions III and 

 IV being obtained with large iron and steel bars f -inch diameter, and 

 using apparatus, fig. 3. A weaker solution of cupric bromide was 

 employed for the iron bar experiments in Division III, and the bars 

 were not immersed so deeply in the solution. The electro-positive 

 position of the coil-bar A was dependent on the extent of its magnet- 

 isation, in these as in the other experiments, and the effects with 

 cupric bromide were generally similar to those obtained with cupric 

 chloride. 



Nickel Chloride, Col. 17, Divisions I and II, was a concentrated 

 solution of the salt in water. 



Sulphate of Iron. — A pair of steel bars were left in a yellow 

 oxidised solution of sulphate of iron in apparatus, fig. 4, for twenty- 

 four hours, the bar A having been magnetised for a short time at 

 commencement only, the residual magnetism being allowed to com- 

 plete the effect; an E.M.F. of O'Oll volt was gradually reached, the 

 magnet bar being in the positive position. 



The Electro- chemical Effect as between the Magnetic Polar Terminals 



and Equator. 



In casting about for an explanation of these magneto-chemical 

 phenomena, it seemed probable that the effect might possibly be con- 

 nected with the local currents w r hich are shown below to develop in a 

 magnetised bar between the more highly and less magnetised parts 

 thereof, when the rod was immersed in suitable solutions acting 



vol. XLIY. X 



