S/ff WILLIAM SIEMENS, F.R.S. 389 



with pig metal and such other ingredients as serve finally to 

 adjust the quality of the steel. The process may be described as 

 follows : The furnace having been heated up to the steel-melting 

 point, or say, 3,500 F., the first duty of the steel-melter is to see 

 that the silica bottom and tapping hole are in the proper condition 

 for work. If, in consequence of wear caused by previous charges, 

 the surface-bed should be pitted, white sand, previously calcined, 

 is introduced in such quantities as to fill up the inequalities, and 

 heat is allowed to act for eight or ten minutes with the furnace 

 doors closed, by the end of which time the silica or white sand 

 introduced will be partially melted and consolidated with the 

 older portion of the furnace-bed. The tapping hole is filled up 

 with white sand mixed with powdered anthracite or coke, which 

 serves to prevent its entire consolidation, and thus facilitates the 

 tapping of the furnace at the end of the operation. 



These preliminary operations completed, the furnace is charged 

 with say six tons of pig metal, mixed with two tons of such iron 

 or steel scrap, as gits, spillings of previous operations, old iron or 

 steel rails, that may be available. The furnace doors are there- 

 upon closed, and heat is allowed to act upon the charge for two 

 hours and a half, when it will be found to have fused, and analysis 

 would prove the metal to be an intermediate condition between pig 

 iron and steel, its percentage of both carbon and silicon being greatly 

 reduced. The subsequent work of oxidation of these ingredients 

 consists in the introduction, at intervals of about half-an-hour, of 

 rich ores or oxides of iron, in charges of about 5 cwt. each ; the 

 immediate effect of the introduction of each charge is an active 

 ebullition, through the reaction of the oxide of the ore upon the 

 carbon of the metal, producing carbonic oxide. This gas escapes 

 to the surface, whereas the iron contained in the ore or oxide 

 becomes metallic, and is added to the bath. "When about 25 cwt. 

 of ore have been thus added, a sample is taken from the bath, by 

 means of a small iron ladle, and subjected to a simple mechanical 

 test, whereby the percentage of carbon remaining in the metal is 

 readily, though somewhat roughly, ascertained. If it appears 

 from the test that the carburization is nearly completed, no more 

 ore is added, but 3 or 4 cwt. of limestone are thrown into the 

 lurnace, which has the effect of combining with the silicon con- 

 tained in the slag, and of liberating ferrous oxide from the same, 



