52 Obfervattons on Iron and Steel. 



fteel, a fubftance intermediate between crude and malleable 

 iron. 



The furnaces for making fteel are conical buildings ; about 

 the middle of which are two troughs of brick or fire-ftone, 

 which will hold about four tons of iron in the bar. At the 

 bottom is a long grate for fire. The fteel furnace, how- 

 ever, is not well adapted for defcription. I fhall therefore 

 avail myfelf of an accurate drawing, which was communi- 

 cated to me by a gentleman converfant with the manufacture, 

 and which is copied in the plate. A layer of charcoal-duft 

 is put upon the bottom of the trough, and upon that a layer 

 of bar iron, and fo on alternately until the trough is full. It 

 is then covered over with clay to keep out the air ; which, if 

 admitted, would effectually prevent the cementation. When 

 the fire is put into the grate, the heat paffes round by means 

 of flues, made at intervals, by the fides of the trough. The fire 

 is continued until the conversion is complete, which gene- 

 rally happens in about eight or ten days. There is a hole in 

 the fide, by which the workmen draw out a bar occafionally, 

 to fee how far the tranfmutation has proceeded. This they 

 determine by the blifters upon the furface of the bars. 



If they be not fufficiently changed, the hole is again clofed 

 carefully, to exclude the air ; but if, on the contrary, the 

 change be complete, the fire is extinguifhed, and the fteel is 

 left to cool for about eight days more, when the procefs for 

 making bliftered fteel is finifhed. For fmall wares, the bars 

 are drawn, under the tilt hammer, to about half an inch 

 broad and -,^ of an inch thick. The change wrought on 

 bliftered fteel by the tilt hammer, is nearly fimilar to that 

 effe&ed on iron from the refinery by the forge hammer. It 

 is made of a more firm texture, and drawn into convenient 

 forms for ufe. German fteel is made by breaking the bars 

 of bliftered fteel into fmall pieces, and then putting a num- 

 ber of them into a furnace ; after which they are welded to- 

 gether and drawn to about eighteen inches long 5 then dou- 

 bled and welded again, and finally drawn to the fize and fhape 

 7 required 



