170 



Hot Blast in the Smelting of Lead. 



Should the writer be able to repay thereby a moiety of debt which 

 is constantly accruing against him by the scientific labors of 

 others, as published in your Journal, he will be much gratified. 



To reduce the sulphuret of lead, merely requires that the 

 sulphur should be disposed of by combustion ; hence a process 

 so simple is partially effected by the most simple means. Yet 

 it can only continue successful, when the heat is not so high as 

 to fuse the galena, and when all parts of the ore undergoing the 

 process, are well supplied with atmospheric air to effect this com- 

 bustion. If the blast be heated and made to diffuse itself equally 

 through the whole ' charge,' carrying with it the flame of light 

 fuel, pine or other light wood leaving but little coal, the reduction 

 of the ore is effected with an economy and dispatch, hitherto un- 

 known in the processes of reducing this metal. The following 

 is a description of the hot blast furnace, used at Rossie in the state 

 of New York. The form of the furnace is not new. 



Fiff. 1. 



ri-U 



r^ 



1 S 6 a 



I I I I I III I n 



Scale of inches. 



A (fig. 1,) is a cast iron reservoir twenty four inches square and 

 twelve inches deep, the iron of the sides and bottom is two inches 

 thick ; to this is attached the hearth B, with flanges projecting at 

 the sides, the whole twenty two inches in length, and including 

 the flanges thirty two inches wide. The hearth descends about 

 one inch in twelve, and has a groove for the melted lead to dis- 

 charge into the reservoir C, in which it is kept fused by a small 

 fire under it, D, is a cast iron air-chest, making an iron wall four- 

 teen inch^ high, above the sides of the reservoir. It is six inch- 

 es thick outside ; the iron being about three fourths of an inch 



