254 Mr. 11. Hunt on the supposed hijiuence of 



not to possess polarity, was placed in a glass tube, around 

 which was wound four or six coils of copper wire carefully 



covered with sealing-wax. Thus arranged, it was placed in 

 a vessel holding diluted sulphuric acid (D), and another wire, 

 sometimes of copper and sonietimes of iron (i), being placed in 

 the same solution, both were connected by long copper wires 

 with a galvanometer (E), placed at such a distance as to be 

 entirely removed from the influence of magnetic attraction. 

 One wire from the helix was connected with a pole of a gal- 

 vanic battery (F), consisting of one or more pairs of plates, the 

 other wire being so placed that the circuit could be readily 

 made or broken. This arrangement being completed, every- 

 thing was so secured that the wires in the electrolyte should 

 not suffer the slightest disturbance when connection was made 

 or broken between the helix and the battery. 



It is evident by this means, a very delicate galvanometer 

 being used, that I secured a most accurate measurer of the 

 chemical action excited by the acid and the iron wire ; that I 

 had the power of rendering the iron magnetic at pleasure, and 

 of using any amount of force I thought proper. 



An iron and a copper wire being immersed in the electro- 

 lyte, the astatic needles of the galvanometer were allowed to 

 come to absolute rest, and the permanent deflection observed. 

 The circuit with the battery through the helix was now com- 

 pleted, and consequently, by induction, the iron rendered 

 powerfully magnetic. In every instance, upon either making 

 or breaking connection, the needle of the galvanometer vi- 

 brated from 3'^ to 5°, but steadily returned to its permanent 

 deflection, as previously noted. 



This transient disturbance of the needle arose from the pas- 

 sage of an induced current through the electrolyte, and by the 

 v/ires to the galvanometer, and was evidently not at all due to 

 any magnetic influence. It was a case precisely similar to the 



