ELECTROCHEMISTRY RICHARDS. 175 



be used, but alternating is preferred because of its easier generation 

 and management, capability of being stepped up or down by trans- 

 formers, and absence of electrolytic effects. 



Electric furnaces render remarkable and highly valuable service to 

 the chemist and metallurgist, for two distinct and unique capabilities; 

 they can generate heat within themselves without the use of combus- 

 tion and the consequent products of combustion to complicate the 

 working of the furnace, and they can besides, if desirable, produce 

 temperatures absolutely unapproachable in furnaces using fuel, and 

 thereby enable the carrying out of operations only possible at these 

 extremely high temperatures. The upper limit of electric furnace 

 temperature is simply the volatilizing point of carbon, the tempera- 

 ture at which the material of which the lining of the furnace is made 

 is boiled away. This is about 3,700° C. or 6,700° F. The simple 

 statement that this is three times as high as the melting point of cast 

 iron may give some notion of the enormous temperature here at one's 

 command. Besides intense temperature, the efficiency of application 

 of electrical heat to the useful purpose is usually high; in many cases 

 50 to 75 per cent of all the heat developed can be usefully applied, as 

 against 5 to 50 per cent utilized in fuel-fired furnaces. The heating 

 value or thermal equivalent of the electric current is perfectly defi- 

 nitely known; 1 kilowatt-hour will furnish 860 calorics (3,400 B. t. u.), 

 which if applied usefully at 100 per cent efficiency would bring to 

 boiling and convert into steam 1.35 kilograms (3 pounds) of water, or 

 bring to melting and melt about 3 kilograms (7.5 pounds) of cast iron, 

 or 2.5 kilograms (5.5 pounds) of steel. 



Artificial graphite is a product particularly electrochemical in its 

 manufacture. Your fellow townsman, Dr. E. G. Acheson, has prac- 

 tically created this industry and his name sticks to the product — 

 Acheson graphite. No temperature but that of the electric furnace 

 can convert the ordinary amorphous carbon, containing small amounts 

 of foreign substances, into pure, soft, homogeneous, unctuous 

 graphite. The purity of the product and its quality has even sur- 

 passed the artifice of mother nature herself. Whereas, before, graphite 

 in small scales was laboriously gathered from Ceylon and Siberia, 

 and with great pains worked up into graphite articles, now the articles 

 are simply molded in ordinary impure amorphous carbon, and con- 

 verted through and through, retaining their shape, into finished and 

 complete graphite articles. What this highly pure product is going 

 to do for lubrication, for annihilating the friction of the world's 

 machinery, perhaps only a few suspect and only Mr. Acheson knows. 

 You will all know more about this soon, and everyone of you who 

 uses machinery will profit by it. Meanwhile, in another direction, 

 probably half the electrochemical industries now operating are bene- 



