120 Notice of some Recent 



be tried is attached. It is then touched on the other side 

 with the end of the other wire of the multiplier, and then 

 the curved portion of the copper wire is plunged into the 

 nitric acid. If the body placed between the two wires is a 

 conductor of electricity, the magnetic needle instantly 

 deviates. He has also found, that a thermo-electric cy- 

 linder is very convenient ; it is formed, by soldering, end to 

 end, two small cylinders, the one of Bismuth, and the other 

 of Antimony. When placed in a glass tube and slightly 

 heated at the point of union, it was placed in contact on 

 one side, with one of the wires of a multiplier, and on the 

 other, with the substance to be tried, and touched at its 

 opposite extremity, with the other wire of the multiplier. 

 The results were similar to those obtained by the first 

 method ; Arsenic and Tellurium were found to be conductors* 

 2. Chemical action of electrical currents. — The experiments 

 of M. Botto, lead to the conclusion, that the direction of a 

 magneto-electric current, has an influence like that of a 

 hydro-electric current upon the facility which it may have 

 in passing through the same system of conductors. Mr. 

 Faraday has proved, that the different substances which 

 form a circle, experience in similar circumstances, an equal 

 magneto-electric induction, and, consequently, a tendency 

 to produce the same current. Botto has confirmed this 

 fact. He disposed a magneto-electric helix, having two 

 distinct and equal ends, in such a manner, that when it 

 was traversed in a contrary direction by two currents deve- 

 loped by influence, these two currents neutralized them- 

 selves. If in the circle, which these currents are obliged 

 to traverse, we place a vessel filled with acidulated water, 

 and communicating with the conductors on one side by a 

 wire, on the other side by a plate of the same metal, the 

 currents are neutralized. But, if one of them is made 

 stronger than the other, by a change in the number of the 

 spirals in the magneto-electric helix, the effect upon the 

 galvanometer which results from this difference of inten- 

 sity, is much more decided, when the most powerful cur- 

 rent passes into the liquid from the wire to the place, than 

 in the contrary direction. Hence, it would appear, that 

 we are to attribute the double phenomenon which the same 



* Journ. de Chim. Medic, i. 630. 



