920 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
Carborundum.—Carborundum is the trade name given to a carbide 
of silicon, first made by E. G. Acheson at Niagara Falls, by heating 
coke, sand, and sawdust to a temperature of between 2,000° and 
3,000° C. in an electric furnace of the resistance type. The product 
has the formula SiC, and the manufacture has grown into one of 
considerable importance on account of the excellent abrasive prop- 
erties of the carbide. In 1892, 1,000 pounds of carborundum were 
produced at the Niagara works, whereas in the last year for which 
complete figures are available (1906) the output had increased to 
6,225,000 pounds. For many years the Niagara Falls works sup- 
plied all the demand for this compound. 
Another artificial substitute for emery has also appeared, in the 
form of an electric-furnace product ealled “ alundum,” obtained by 
heating bauxite to a high temperature. In order to meet the in- 
creased competition, the Carborundum Company of the United 
States have arranged to carry on the subsidiary manufacture of 
grinding wheels, abrasive tools, and materials in Germany, a new 
works for this purpose having been erected there in 1906. 
Tucker and Lampen have recently carried out some laboratory 
experiments with carborundum, and have found that the temperature 
originally given by Acheson for its formation and dissociation are 
too high. According to Acheson these temperatures were over 2,500° 
C., while Tucker and Lampen give 1,600° to 1,900° and 2,220° C. 
Copper.—The electrolytic copper-refining industry is the oldest 
of the electro-metallurgical industries, having been started by James 
Elkington at Pembrey in South Wales in the year 1869. The process 
and methods used by Elkington in this small refinery were similar 
in all respects to those in use at the present day, copper sulphate 
being employed as the electrolyte with raw-copper anodes and thin 
sheets of pure copper as cathodes. The only change has been in 
the magnitude of the operations. At Pembrey the electrolyte was 
contained in small earthenware pots, and the output was 15 hundred- 
weight per day, or 250 tons per annum. ‘To-day there is one refinery 
in America producing electrolytic copper at the rate of 350 tons per 
twenty-four hours, and the aggregate output of all the refineries 
is estimated at 400,000 tons, or 53 per cent of the total raw-copper 
production of the world. This enormous growth of the industry 
has occurred chiefly in recent years, the capacity and output of the 
American refineries, which contribute over 85 per cent of the total, 
having been doubled within the last seven years. The expansion 
is due partly to the great demand for a very pure copper for elec- 
trical purposes and partly to the presence of silver and gold in the 
American raw copper, in sufficient amount to pay for their recovery 
from the slimes obtained in the electrolytic process of copper refin- 
