186 EF. H. Hail—New Action of Magnetism, ete. 
rent, the wax began to melt and melted most rapidly where 
the current was strongest, thus roughly showing the distribu- 
now subjected to the action of an electro-magnet, but no change 
could be detected in the behavior of the melting wax, the cur- 
rent remaining apparently unchanged in its course through 
the disk. is experiment therefore, like the preceding, was 
negative in its indications. 
A recent number of the “ Beiblatter zu Wiedemann’s Anna- 
len” mentions, in connection with the researches of Feilitzch 
and Mach, another by Gore.* The latter took a wire bifur- 
into the other branch more than its normal share. It was 
thought that an unequal division of the current might show 
itself by a change in the appearance of the white hot branches. 
No change of this kind could be detected, and the investigator 
therefore concluded that the action known to take place be- 
tween conductors bearing currents, was not an action between 
the electric currents as such. Gore expressly states that he 
undertook this experiment not knowing that any previous in- 
vestigations with the saine aim had ever been made. 
On the same page of the “Galvanismus” which treats of the 
research of Mach, as mentioned above, Wiedemann describes, 
as a means of showing that no action takes place between per- 
manent electric currents as such, almost the exact arrangement 
of apparatus with which the discovery was finally made. Who 
first used this apparatus for this purpose I cannot say, unless 
it may have been Wiedemann himself. The same plan was 
hit upon by Professor Rowland,t+ quite independently I believe, 
and he experimented to some extent in this direction about the 
year 1876. The same arrangement was finally adopted by me 
after another method of attacking the problem had been unsuc- 
cessfully tried. 
I desire to express my sense of obligation to the professors 
and students of the physical department of the Johns Hopkins 
University, for the generous assistance which they have ren- 
dered me during the progress of this research. 
e Attraction of Magnets and Electric Currents,”—Phil. Mag. (4th 
series), vol. 48, p. 393, 1874. 
+ Amer. Jour. of Math., vol. ii, p. 289. 
