On the supposed Helical Path of the Electric Current. 



423 



by potassic chlorate is proportional to the weight of the che- 

 mically inactive salt present, and that the amount of this 

 retardation is the same for equal weights of those salts which 

 more or less resemble each other constitutionally. This is 

 seen to hold for the sulphates of the alkaline metals and am- 

 monium, and also for the two alums; "but in the case of the 

 sulphates of zinc and magnesium the difference in their effects 

 is too considerable to permit of their being classed together, 

 in a dynamical sense, however much they may resemble each 

 other statically. The fact that equal weights of the alkaline 

 sulphates or the alums produce equal effects, shows that the 

 retardation produced by a single molecule of those salts which 

 belong to the same group is proportional to its weight. 



Mills and Walton have shown* that, in the formation of 

 ammonia by the action of zinc amalgam on potassic nitrate, 

 the presence of sodic or potassic sulphate produces an accele- 

 ration in the reaction, and that equal weights of the two salts 

 have, as nearly as possible, equal working effects. 



My best thanks are due to Dr. Frankland, in whose labora- 

 tory the above experiments were made. 



LIV. Note on the supposed Helical Path of the Electric Cur- 

 rent in longitudinally Magnetized Conductors. By J. A. 

 Ewixg, B.Sc, F.R.S.E., Professor of Mechanical Engineer- 

 ing in the University of Tokio, Japan\, 



IN a paper entitled "Molecular Magnetism," read before 

 the Royal Society on May 19, Prof. Hughes describes 

 experiments which have led him to the conclusion " that the 

 path of an electric current through an iron or steel wire is that 

 of a spiral." Prof. Hughes mentions that the wires experi- 

 mented on were never entirely free from longitudinal magne- 

 tization to begin with, and that when they were further mag- 

 netized the effects observed, which formed the ground of the 

 conclusion just quoted, were greatly increased. It may fairly 

 be assumed that these effects were in all cases due to the pre- 

 sence of longitudinal magnetism in the wires. 



The object of this note is to point out that the experimental 

 results obtained by Prof. Hughes admit of another interpre- 

 tation than that which he has given them, and at the same 

 time to suggest a method of determining whether there is, or 

 is not, any such helical quality in the path of the current as he 

 has inferred. 



* Proc. Roy. Soc. 1879. 



t Communicated by the Author. 



