162 



Mr. T. Andrews. 



[May 3, 



This class of observations indicated that the results were influenced 

 by the extent to which the metal was magnetised ; the latter fact was 

 more distinctly shown in course of experiments with bromine and the 

 salts of copper. 



Division TV. — These experiments were made on fche small steel bars 

 with apparatus, fig. 4; the general results were similar to those 

 obtained with the larger bars, though somewhat less in extent. The 

 bar A in the coil was magnetised for a short time only at the com- 

 mencement, and the induced permanent magnetism allowed to com- 

 plete the result. 



Ferric Chloride, Col. 11, Divisions I, II and III, was a saturated solu- 

 tion of the salt in water. The experiments in Division I were made 

 in apparatus, fig. 4, equality of temperature obtaining between the 

 two limbs of the [J -tube. The observations of Division II were made 

 in the water-bath apparatus previously alluded to, with a difference 

 of temperature of about 5° to 10° F. in favour of the immagnetised 

 bar ; the magnetic influence was, however, sufficient to overcome this 

 temperature obstacle, and even under such conditions the magnetised 

 bar maintained its electro-chemical position, though not to the full 

 extent. On ceasing to magnetise a bar in the above reagent, the 

 E.M.F. steadily diminished, and on again applying magnetisation 

 the magnetised bar resumed its positivity. The observations in 

 Division III were made on pairs of the small steel bars under equal 

 temperature conditions. At the end of forty hours there was a per- 

 ceptibly greater deposit of flocculent oxide of iron in the tube con- 

 taining tne magnetised bar. 



Cupric Chloride, Col. 12, Divisions I and II, consisted of a concen- 

 trated solution of the salt in water, such as is usually employed in 

 dissolving out the metallic iron in the carbon determination of iron 

 analyses. The magneto- chemical effect with this reagent was of con- 

 siderable magnitude, a powerful effect commencing from first magnet- 

 isation of the bar A, and largely though steadily increasing. On ceasing 

 to magnetise the bar A the galvanometer deflections were reduced ; 

 but on again bringing the magnetising coil into action, the magnetised 

 bar A steadily re-asserted its strong positive position in course of a 

 few moments. These magnetic effects were not of such a nature as 

 to produce a very violent fling of the galvanometer, but manifested a 

 steady and permanent character, though in most instances deflections 

 commenced at once on magnetising the bar A, and afterwards con- 

 tinued steadily to increase till the maximum point was reached. On 

 the completion of an experiment, both bars were of course covered 

 with electro-deposited metallic copper; but in many instances the 

 colour of the solution in the limb of the \J -tube which had contained 

 the magnetised ba~, was of a rather lighter tint, showing that a some- 

 what greater deposition of copper had occurred therein. The experi- 



