600 TRANSACTIONS OF THE 



which is provided with a slide valve, or shutter, K. The ores 

 are then, at suitable intervals of time, removed to the draft open- 

 ing, G, through which they are thrown down to the middle 

 chamber, B; they are next thrown down openings F. into the 

 lower chamber. A; next they are removed to the lower chamber 

 to the finishing basin, L, near the fire, D, where the eifects of the 

 heat are completed, and whence they are taken out, in the metallic 

 state, ready for the hammer. 



Through the sides of all the chambers, openings, M, are made, 

 through which the ores and materials may be frequently agitated 

 by suitable instruments, and moved along from one end of the 

 several chanibers to the other, and finally through N, the metal 

 may be molded and taken out from the furnace. The ashes are 

 removed at 0. 



There are also openings for the blast, for the fuel, and for the 

 letting off of any liquid matters which may accumulate in the 

 finishing furnace. Through the floor of the lower chamber there 

 is an opening, P, in the end opposite the fire, tlirough which may 

 fall the cinders and ashes, and other solid materials carried along 

 thither by the draft. For the same purpose other suitable recep- 

 tacles are provided in the other chambers. 



To prevent any undue accumulation of heat in the middle and 

 upper chambers, or to prevent the introduction to said chambers 

 of cold air, or air charged with oxygen, coming through openings 

 in the lower chamber, flues, Q, are made to lead from the lower 

 chamber upwards, directly through the top of the furnace. These 

 flues are ordinarily kept closed by dampers, R, and when they 

 are opened the draft is prevented from pursuing its ordinary 

 passage by a damper, S, on the top of the chimney. 



To prevent the too violent effects of the heat, openings, T, are 

 made in sides and ends of the furnace, f:>r the introduction of 

 cold air between the roofs and floors of the chambers. The floors 

 of the several chambers may be either horizontal or inclined. 



The lower chamber, A, is raised up from the ground for the 

 convenience of working, for the easy flowing away of liquid im- 

 purities, and for the falling down of ashes and cinders. This 

 process is alleged to afford the following advantages : — 



1 . The gradual heating of the ores with the necessary materials 

 for their reduction as they are moved nearer to the fire from 

 chamber to chamber, and from one end of a chamber to the other. 



2. Opportunity is afforded for the frequent agitation of the ores 

 and materials, by which agitation the impurities are freely allowed 



