228 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
level of liquid in these, the drift of copper ions, dissolved at the 
anode, toward the cathode compartment is stopped, and only pure 
nickel is deposited at the cathode. The electrolyte becomes continu- 
ously richer in copper and iron, and is regenerated by passing over 
slabs of nickel or of a nickel-copper alloy. The copper is deposited 
and the nickel takes its place, while the iron is removed at a later 
stage by oxidation. The solution then contains only nickel sulphate, 
and is ready for use again in the vats. 
_ Silowicon——This is the name given to an electric-furnace product 
made by Acheson at Niagara Falls, by heating carbon and silicon in 
a fine state of subdivision and well mixed, to a temperature slightly 
below that required to produce carborundum. The product is a 
highly refractory material, and a company has been floated in the 
United States for the manufacture of siloxicon crucibles, muffles, 
bricks, etc. The chief difficulty in the manufacture of siloxicon is 
the regulation of the temperature, since if this be raised too high 
(above 1,700° C.) the oxygen escapes and carborundum is produced. 
Silicon.—F. J. Tone has produced this metal in large amount. at 
Niagara Falls by heating sand with carbon in an electric furnace of 
the resistance type. It is essential that the raw materials be finely 
ground and well mixed, and that the temperature be carefully regu- 
lated to prevent formation of carbides. The metallic silicon must be 
drawn off as formed, the process being continuous, and the metal 
obtained bright and crystalline. Tone states that the metal may be 
used as a deoxidizer in the iron and steel industry and as a substitute 
for aluminium in the “ thermit ” mixture; but the demand for silicon 
for these and other purposes does not appear to have developed, and 
the difficulty at present is to find a market for the product. 
Sodium.—The production of this metal by the electrolysis of the 
fused hydrate has grown in recent years into an important industry, 
and the older chemical method of manufacture has now been quite 
supplanted by the electrolytic method. The Castner cell and process 
are generally employed. Installations of this cell are now working in 
England, America, France, and Germany. The manufacture of me- 
tallic sodium in England is in the hands of the Castner-Kellner Alkali 
Company. The plant has recently been transferred from. Weston 
Point to Wallsend-on-Tyne, where a new works has been erected, the 
power required being purchased from the Newcastle and District 
Electric Supply Company at a very low rate. 
Ashcroft has patented a cell and process recently by which sodium 
chloride can be substituted for the hydrate in this manufacture. This 
process is about to be tried upon an industrial scale in Norway. 
Should the attempt succeed, the cost of metallic sodium, which has 
