154 Mr. H. L, Pattinson on Smelting Lead Ore, <§-c. 



At Plate I., Fig. 1, is a perspective view of the Roasting Furnace. 



Its bed or bottom, inside, upon which the charge of ore is spread to re- 

 ceive the action of the fire, is usually about six feet square, quite flat and 

 formed of fire bricks, set upright upon their ends, and in contact. The 

 fire-place is 3 feet 4 inches long, by 1 foot 4 inches broad, which, with 

 the roof and sides, is formed of fire-bricks, enclosed by solid masonry, 

 and strongly bound together by iron bars. The tease-hole, through which 

 coals are supplied to the fire, is not represented in the figure, being, in 

 this case, on the opposite side of the furnace. Three doors are usually 

 formed on each side when convenience admits of it, through which, and 

 an end door b, the ore can be turned and raked backwards and for- 

 wards ; the middle door a in front, is made larger than the Others, for 

 the purpose of more easily introducing and withdrawing the charge of 

 ore. Immediately below this door is a trough c, 18 inches deep, 2 feet 

 wide, and 4 feet long, filled with water, into which the ore is suffered 

 to fall red hot when raked out of the furnace ; and directly above this 

 door is a wide-mouthed sheet-iron tube, d, communicating with the 

 chimney, through which the unwholesome effluvia of the ore is con- 

 ducted away, without injuring the workmen, during the operation of 

 withdi'awing the charge. A moveable iron screen e is at the same 

 time placed over the trough, against the side of the furnace, within 

 which the ore falls, effectually preventing the escape of noxious vapour. 



Although the construction and size of the roasting furnaces, at most 

 of the smelting mills in this district, are nearly alike, yet considerable 

 difference is found in the rate and mode of working them. At some 

 places, two men manage a furnace, into which one bing of ore is put 

 at a charge, and the furnace is charged and drawn five times in eight 

 hours. Each pair of men work 8 eight-hours-shifts per week, and are 

 relieved at the end of each shift by another couple, who work with 

 them alternately eight hours on and eight off; in this manner roasting 

 eighty bings of ore per week in one furnace. 



At other places three charges, making together four bings of ore, 

 are worked in eight hours by one man ; and three men, working each 

 six shifts per week, roast in one furnace seventy-two bings of ore ; and, 



