210 



them. Under these conditions, Mr. Herschel observes, the pheno- 

 menon may admit of explanation, from what \ve already know of the 

 passage of electricity through conductors, and the high attractive and 

 repulsive powers of the two electricities inter se. A body so highly 

 positive as potassium, present in the mercury, may, for instance, have 

 its natural electrical state exalted by its vicinity to the positive pole ; 

 and being thus repelled, may take the only course the resistance of 

 the metal on the one hand, and attraction of cohesion on the other, 

 will permit, viz. along the surface, to recede from the positive pole ; 

 it may even act as a carrier to the positive electricity, which may ad- 

 here to it too strongly to be transmitted through the mercury, and 

 when arrived at the opposite side of the globule may there, by the in- 

 fluence of the opposite pole, lose its exalted electrical state. Such 

 an explanation, however, is not without its difficulties ; and although 

 another is open to us, that of considering the action which takes 

 place at the common surface of two unequally conducting media as 

 dependent upon a new power of the electric current, bearing some 

 analogy to magnetic action, yet this, in the present state of the 

 investigation, must be regarded not only as a bold, but vague hy- 

 pothesis. 



Experiments and Observations on the Development of Magnetical Pro- 

 perties in Steel and Iron by Percussion : Part II. By William 

 Scoresby, Jun. F.R.S.E. #e. Communicated by Sir Humphry 

 Davy, Bart. Pres. R.S. Read January 29, 1824. [Phil. Trans. 

 1824, p. 197.] 



After adverting to the general results of his former inquiries, the 

 author observes that his principal objects on the present occasion 

 were to endeavour, by auxiliary rods of iron, to increase the degree 

 of magnetism ; and to ascertain on what circumstances, as to the 

 magnitude of the iron rods, and the quality, size, and temper of the 

 steel wires, the utmost success of the method depends. 



He fonnerly used a single iron rod, upon which the steel bars were 

 hammered, both being in a vertical position. He now places the steel 

 wire between two rods of iron, and subjecting it, through the medium 

 of the upper rod, to percussion, derives the advantage of the magnet- 

 ism of both rods of iron acting at the same time upon both its poles. 

 The rods he used were of the respective lengths of three and one foot, 

 and an inch diameter ; and the upper end of the larger rod and the 

 lower one of the smaller rod were made conical, there being an in- 

 dentation in each to receive the ends of the steel wire. Some mag- 

 netism was then elicited by percussion in the larger rod, and the 

 steel wire being properly placed between its upper extremity and the 

 lower one of the small rod, the upper end of the latter was ham- 

 mered, and magnetism thus communicated to the wire ; whilst the 

 lower rod, receiving some influence from the percussion, performed 

 a similar office. The author calls this mode of proceeding, the com- 



