352 ELECTRICITY DURING THE NINETEENTH CENTURY. 



energy for lightinji- and for motors, including railwa3\s, other recent 

 uses of olectricitv to whicli we haxc not yet alluded are splendidly 

 exemplified at Niagara. Davy's brilliant discovery of the alkali metals, 

 sodium and potassium, at the opening of the century, showed the great 

 chemical energy of the electric current. Its actions were afterwards 

 carefully studied, notably I)}" the illustrious Faraday, whose discoveries 

 in coimcction with magnetism and magneto-electricity have been briefly 

 described. The electric current was found to act as a most potent 

 chemical force, decomposing and recomposing many chemical com- 

 pound-i, dissolving and depositing metals. Hence earl}- in the century 

 iirose the art of electroplating of metals, such as electro-gilding, silver- 

 plating, nickel-plating, and copper deposition, as in electrotyping. 

 These arts are now practiced on a very large scale, and naturally have 

 affected the whole course of maiuifacturing methods during the cen- 

 tury. Moreover, since the introduction of d3Miamo current electrol3'sis 

 has come to l)e employed in huge plants, not only for separating metals 

 from each other, as in refining them, but in addition for separating 

 them from their ores, for the manufacture of chemical compounds 

 before unknown, and for the cheap production of numerous substances 

 of use in the various arts on a large scale. Vast quantities of copper 

 are refined and silver and gold often obtained from residues in sufficient 

 amount to pay well for the process. 



At Niagara also ai"e works for the production of the metal alumi- 

 num from its ores. Similar works exist at other places here and 

 abroad where power is cheap. This metal, which competes in price 

 with ])rass. bulk for bulk, was only obtainable before its electric re- 

 duction at $25 to $30 per pound. The metal sodium is also extracted 

 from soda. A large plant at Niagara also uses the electric current for 

 the manufacture of chlorine for bleach, and caustic soda, both from 

 common salt. Chlorate of potassium is also made at Niagara by 

 electrolysis. The field of electro-chemistrv is indeed full of great 

 future possibilities. Large furnaces heated by electricity, a single 

 one of which will consimie more than a thousand horsepower, exist 

 at Niagara. In these furnaces is manufactured from coke and sand, 

 by the Acheson process, an abrasive material called carborundum, 

 which is almost as hard as diamond, but quite low in cost. It is made 

 into slabs and into wheels for grinding hard substances. The electric 

 furnace furnishes also the means for producing artificial plumbago, or 

 graphite, almost perfectly pure, the raw material being coke powder. 



A large amount of power from Niagara is also consumed for the 

 production in special electric arc furnaces of carbide of calcium from 

 coke and lime. This is the source of acetylene gas, the new illumi- 

 nant, which is generated when water is brought into contact with the 

 carbide. The high temperature of the electric furnace thus renders 

 possible chemical actions which under ordinary furnace heat would 



