CONSTRUCTION OF BLAST FURNACES. oi> and permit this portion of the furnace brick-work to be exposed to the cooling influence of the atmosphere as much as possible. It is at this part of the bosh and hearth that the lining is subjected to the greatest heat. Furnaces are contracted at the hearth__ which constitutes all that portion below the tuyere at B, mainly to aid the blast in reaching the center more strongly and causing a more even distribution of its pressure throughout the fuel, as well to save the lining. Such a form not only assists the blast to reach the center, but the "batter "or bevel of such a bosh as shown assistsin supporting the weight of stock FIGs. 6. *,*.•. v vvwj.£.u.t Ul SLOCK Charged, thus lessening pressure at the. tap hole, permitting the metal to be under better control, with less iability to cut the breast as the metal flows out to the t; them than in lost iron.