52 Canadian Record of Science. 



which are 45 and 90 English feet in diameter. This propor- 

 tion 11 : 12, would here give 50 and 100. 



It is not unlikely that the prehistoric foot-unit of 11 '0 

 inches has simply been derived, not from any cubit, but from 

 the length of the human foot, which would also be about 

 one third of the military pace of H3 inches. 



In my next communication I hope to say something more 

 definite with regard to Central American and Peruvian units 

 of measure, and which appear to present certain peculiari- 

 ties and difficulties. 



An Electrical Furnace for Reducing- Refrac- 

 tory Ores. 1 



By T. Stekry Hunt. 



The application of electricity in the extraction of metals 

 has hitherto been chiefly confined to the electrolysis of dis- 

 solved or fused compounds of these by various methods. 

 The power of electric currents to generate intense heat in 

 their passage through a resisting medium has, however, 

 long been known, and the late W. Siemens thereby suc- 

 ceeded in fusing considerable quantities of steel. But it 

 was reserved to Messrs. Eugene H. and Alfred H. Oowles, 

 of Cleveland, Ohio, to take a new step in the metallurgic 

 art by making the heat thus produced a means of reducing, 

 in the presence of carbon, the oxides not only of the alkaline 

 metals, but of calcium, magnesium, manganese, aluminium, 

 silicon, and boron, with an ease that permits the production 

 of these elements and their alloys with copper and other 

 metals on a commercial scale. 



In the apparatus devised and now employed by the 

 Messrs. Cowles, a column of fragments of well-calcined 

 charcaal, so prepared and arranged as to present the 

 requisite electrical resistance, is imbedded horizontally in 

 finely pulverized charcoal, and covered by a layer of the 



'Read Sept. 17, 1885, before the Halifax, N. S., Meeting of the 

 American Institute of Mining Engineers, and reprinted from the 

 Transactions. 



