Intelligence and Miscellaneous Articles. 323 



showing thus that the electrolytic decomposition which takes place 

 is under the conditions which characterize the ordinary voltaic pile, 

 or a magneto-electrical machine with adjusted currents. 



In a sulphate -of- copper voltameter, metal is dissolved at one pole, 

 while copper is deposited electro- chemically at the other. 



2. In the dialyzing voltameter, acidulated water is not essen- 

 tial for the production of the phenomena. Most salts we have 

 used modify the normal action of alternating currents ; but all of 

 them possess the property of rectifying the extra currents of one 

 series. 



The use of a solution of chloride of magnesium gives rise to a 

 light of the greatest beauty. The electrode, which is immersed to 

 a depth of a few millimetres, immediately becomes covered with 

 metallic magnesium, which is at once burned with the produc- 

 tion of a bright light. In this experiment, the platinum wire may 

 be replaced by one of iron, which then itself burns slowly, in- 

 creasing the power of the light ; in spite of that, if the iron is placed 

 gradually in the liquid, its combustion is slow enough to obtain a 

 very constant luminous eifect. 



After having studied these special properties of induction-currents 

 by the aid of a magneto -electrical machine having high tension, it 

 was necessary to ascertain if the same phenomena could be pro- 

 duced by the aid of a source of electricity having smaller electro- 

 motive force. "With this view we u&ed a ISTollet's machine with 

 eight coils, like the preceding, but surrounded by a wire having 

 but a small resistance. This machine has an electromotive force 

 equal to 22 elements of sulphate of copper. 



When the dialyzing voltameter contained acidulated water, the 

 absorption of one series was also affected. But we have obtained 

 effects of quantity far more intense by using as the liquid a solu- 

 tion of bichloride of mercury in salt water. In this case more of 

 the wire which acquires positive electricity may be immersed in the 

 liquid ; the resistance is thereby diminished. 



At the commencement of the experiment protochloride of mer- 

 cury is formed, which soon after dissolves under the influence of 

 the liberated chlorine. Prom this moment the mercury is seen 

 to form round about the electrode, and separates when a pretty 

 large globule is formed, while the current acquires an intensity 

 the measurement of which will be afterwards girei. The liquid 

 of the voltameter acquires a higher temperature urder the action 

 of the currents. If the position of the electrode be not properly 

 regulated, a moment is reached at which the two currents retain 

 their normal properties, and then the needle of the galvanometer 

 is no longer deflected; but by suitably arranging the position of 

 the electrode in the voltameter, it may easily be retained in a liquid 

 medium at a convenient temperature. 



Adopting this method, and causing the system to act upon a 

 bath of sulphate of copper, we succeeded in obtaining from 7 to 8 

 grammes of electrolytically deposited copper in an hour. 



