752 PKOCEEDINGS OF THE AMERICAN ACADEMY. 



The graphite is used as a filler for dry batteries, and is being applied 

 in place of natural graphite in stove polish, lubrication, foundry facings, 

 and as a pigment for paints. It is easily reducible to a very fine pow- 

 der. The graphite is nearly pure, containing about one-half per cent 

 of impurities when used for electro-chemical electrodes, and about three 

 per cent when used for paint. A good quality of natural graphite may 

 be eighty-five per cent pure, and much of it on the market is as low as 

 forty-five per cent. The solid bars of artificial graphite have a rela- 

 tively high electric conductivity, estimated at about four times that of 

 ordinary amorphous carbon rods. They disintegrate in electro-chemical 

 work at a much lower rate than the former electrodes, for which they 

 have become the substitute. In some cases the life of the electrode is 

 increased twelve times. During 1905 the Acheson Graphite Company 

 produced about two and a half millions of pounds of graphite electrodes 

 and nearly two miUions of pounds of bulk graphite, made principally 

 from anthracite coal. 



" Two other electric furnace products have been added more recently 

 as the outcome of Mr. Acheson's experiments. In attempting to reduce 

 the element silicon by electrically heating an intimatQ mixture of fine 

 graphite and pure silica, the amount of carbon being only that suffi- 

 cient to remove the oxygen, Mr. Acheson noted not only the reduction 

 of the silicon in part, but the production of a quantity of a greenish 

 gray fluffy substance which, from the circumstances of its production, 

 he recognized as highly refractory. The manufacture of silicon itself 

 was turned over to the carborundum company in 1901, since which 

 time this manufacture has been extended and perfected so that the 

 element silicon, once a rare curiosity of the chemical laboratory, seen 

 only in small crystals and in samples of small amount, has become a 

 commercial product of low price. 



" The greenish gray fluffy mass referred to when analyzed gave the 

 formula SigCoO, and was named siloxicon. It is amorphous and said 

 to be inert to acid and basic slag, insoluble in fused iron, and packs or 

 binds itself when pressed and then heated to about 2500 degrees F. 

 Briquettes can thus be made, resisting the highest furnace tempera- 

 tures. Attention is now being given to this substance as a material 

 for crucibles, muffles, fire bricks, fire-resisting linings, etc. 



" Mr. Acheson has contributed several papers to technical journals 

 and societies, an incomplete list being as follows : — 



" 'The Influence of the Condenser on Disruptive Discharges.' Elec- 

 trical World, July 7, 1888. 



" ' Disruptive Discharges and their Relations to Underground Cables.' 

 Before the National Electric Light Association, August 29, 1888. 



