L. MECHANICS AND ENGINEERING. 433 



alysis of which gave 0.8 per cent, silicon, 2.23 per cent, car- 

 bon, and 2.2 per cent, manganese. After the fusion it con- 

 tained 0.7 per cent, silicon, 2.3 per cent, carbon, and 1.3 per 

 cent, manganese. The charges were very hot, and the expec- 

 tation, founded on theoretical considerations, that a slightly 

 carburetted iron could be Bessemerized with hot blast, was 

 confirmed. A larger than usual quantity of ends of rails could 

 also be thrown in, amounting to eighteen per cent, instead of 

 twelve per cent., as with cold blast. Among the practical 

 difficulties that prevented its continuous use was the decided 

 effect upon the lining, which often became useless after two 

 charges, instead of withstaiiding an average of fifteen or six- 

 teen ; and, besides, all portions in contact with the hot blast 

 were so intensely heated that they rendered manipulation 

 difficult, and it would require long practice to accustom the 

 workmen to the heat. For this reason the use of the hot 

 blast was abandoned for the present, although the results 

 were considered favorable. 13 (7, July 1, 1875, 851. 



EXTENDED SERVICE OF A FUKNACE. 



The Emma Furnace managers have communicated to the 



CD 



American Manufacturer the extraordinary announcement 

 that the furnace stood banked up from December 4, 1874, to 

 July 9, 1875, w^ithout blast or draught, during a most severe 

 winter. This is equivalent to seven months and five days, or 

 217 days, and during all of this time it held its fire intact 

 without chillino; or crackimr. On December 4th the iron 

 was run out, and the furnace filled wholly with Connellsville 

 coke, every precaution being taken to have the fire remain 

 until advisable to resume operations. It stood idle until 

 January 9, 1875, and during this entire time not a thing was 

 done to it, or a pound of fuel added. "When opened at above 

 date some two thirds of its coke was alive, and the furnace, 

 after clearing away ashes, etc., was ready to resume opera- 

 tions. This record of the "Emma" has to our knowledfre 

 never been equaled. 



REVOLVING FURNACE BARS. 



Foreign technological journals find a very considerable im- 

 provement in furnace grates in an invention of M. Eloy 

 Schmitz, who replaces the straight fire-bars ordinarily used 

 ^ T 



