Chemical Action by Electrical Induction, fyc. 143 



this case, when the plates are separated by layers of starch, slightly 

 moistened, dry piles are produced which act a long time and charge 

 the condenser, and do not decompose water. 



The electrical currents of these piles may be constant and still 

 their tension be too much diminished to produce chemical action like 

 the decomposition of water. 



The magnet used by M. Pixii, for the decomposition of water, is 

 formed by joining two others. Each of these supports alone twelve 

 and a half kilog. (27.5 lbs.) and they weigh together four kilog. 

 (8.8 lbs.) 



The shaft of the lathe revolves at least six times in a second. The 

 decomposition of the water is increased with the rapidity of the rev- 

 olution of the magnet. 



The piece of soft iron, wound with copper wire, is circular, and 

 its diameter four centimetres, (1.57 inches,) height twenty centime- 

 tres, (7.87 inches,) bent into a horse shoe form, with parallel arras, 

 distant eleven centimetres, (4.33 inches,) reckoned from the center 

 of each circular end ; the silk wire four hundred metres (437.5 yds.) 

 long, and weighs two kilog. (4.41 lbs.) 



2. Of the Electro-Magnetic disc of M. Arago. 



M. A. has demonstrated, (memoir of March, 1825,) 1. that a me- 

 tallic disc turning upon its axis, either above or below a magnetic 

 needle, in the sphere of the magnetic action of the needle, causes it 

 to deviate from its natural position : 2. that the deviation begins and 

 ends with the rotary motion of the disc. 



Mr. Faraday, (memoir before cited,) discovered that in this exper- 

 iment the movable disc is electrified. 



I have attempted to decompose water by electricity communicated 

 to the disc. In the apparatus of M. Pixii just described, I substitu- 

 ted for the magnet a circular disc of copper, and for the wire-wound 

 piece of soft iron, which is useless, a magnet. The ends of the 

 wire of the multiplier were made to communicate with the circular 

 disc, and to secure a perfect contact, each of the ends was terminated 

 by a small plate of copper amalgamated with mercury, and one of 

 the flat edges of the disc was also amalgamated. 



The plates of the wire of the multiplier were secured before the 

 poles of the fixed magnet, at the extremities of the diameter of the 

 disc parallel to the straight line, (a la droite,) which joins the poleS. 



The plane of the disk is on a level with the poles of the magnet 

 without touching them ; the plates of copper resting against the flat 



