CONSTRUCTION OF RETORTS. 87 



that of keeping up the furnace and charging the hopper once in twenty-four 

 hours. No gas is lost, and no tar made. The coke produced is increased in 

 quantity by about 75 per cent., but its quality is not so well fitted for gene- 

 ral purposes (although superior for culinary uses) as that produced by the 

 common process. 



The power employed for turning the shafts may be a water-wheel, which 

 would be preferable to a steam-engine, unless in large works, where the latter 

 could be employed for other purposes. The tank from which the water would 

 flow on to the wheel may, in cases where there is no natural fall, be filled by 

 a hand-pump. An overshot wheel, six feet in diameter and nine inches in 

 breadth of float, would drive twelve retorts at the speed required ; the water 

 for turning such a wheel for twelve hours may be pumped up by two men in 

 about an hour and a half. 



The following is an estimate of the cost of four retorts as shown in the en- 

 graving, exclusive of brickwork : 



s. d. 



Four wrought-iron retorts, each weighing six cwt. at 25s, 30 



Four chambers of No. 9 plate, riveted and made tight - - 35 10 

 Hoppers, four in number, to contain 18 cwt. of coal each, fitted 



with a water-jointed lid at the top - 25 

 Eight revolving drums, to drawing, with shafting, turned bearings 



and stuffing-boxes, complete 2/15 

 Four webs of plate-iron connected by links of round iron, as 



shown in the drawing 550 

 One wrought-iron tank, running the entire length of the bed for 



receiving the coke - 840 



Eight large doors and fittings - 766 



Fire-door, grate and bearing-bars - 250 



141 5 6 



This estimate will appear large when compared with the prices given for 

 common retorts; but the debtor and creditor accounts of the two methods, 

 compared together at the end of twelve months, will be found much in favqur 

 of the above. 



The quantity of gas produced by five D retorts, such as are shown in Plate 

 I., will be about 14,000 cubic feet in twenty-four hours, of specific gravity '390 

 or '400, and the quantity produced by four of the proposed retorts will be 

 43,200 cubic feet in twenty-four hours, of the specific gravity "470 or '490. 



