MECHANICS AND USEFUL ARTS. 63 



beneath a smaller cylinder. The dough, spread out like a large 

 sheet, then passes along an endless cloth, the machinery moving, ^t 

 each stroke, the precise width of a biscuit. As the dough passes 

 along, by the rising and falling of a nicely adjusted piece of mechan- 

 ism, the biscuits are cut into shape and receive the stamp of the pat- 

 entee. The biscuits are not circular, but have six sides, and there- 

 fore there is not, in cutting out, any waste of dough, except a very 

 small portion at each end. Passing along the endless cloth, the bis- 

 cuits are conducted to the mouth of the oven, where they are re- 

 ceived on a machine, which draws in the biscuits in a few seconds. 

 Each oven is 4 feet in width, and 26-J- feet in length. There are four 

 ovens, one above another, and all fed from the same furnace with hot 

 air. The mixing of the flour and water occupies about 12 minutes, 

 the kneading 5 or 6, and firing half an hour. As each oven contains 

 650 biscuits, and they may be filled within a few minutes of each oth- 

 er, there is no difficulty in producing, from flour and water, no fewer 

 than 2,600 biscuits in an hour, or nearly a ton of ship-biscuits every 

 two hours. The biscuits, too, are of excellent quality, beautifully 

 crisp and sweet. 



PREVENTION OF SMOKY CHIMNEYS. 



SIR HENRY HART, the Commissioner of Greenwich Hospital, has 

 lately patented an invention for promoting the draught of chimneys, 

 and thus preventing them from smoking, while at the same time it 

 aids the ventilation of rooms. The apparatus consists of a fan-wheel 

 in the centre of the chimney-top, the axis being horizontal, immedi- 

 ately on a level with the orifice. One half of the wheel thus projects 

 above, and is open to the influence of the wind, while the lower half 

 is shielded from it, and the wheel is therefore made to rotate with 

 great rapidity, and acts like a screw to force up the smoke or vitiat- 

 ed air from below. A diaphragm is placed across one half of the 

 chimney to prevent any air being forced downwards, so that the 

 smoke is confined to one half of the cliimney. Albany Cultivator. 



WIRE AS A SUBSTITUTE FOR LATH. 



FIRE-PROOF ceilings of wire-work have been successfully applied in 

 place of lath, with plaster 'and stucco, as usual, at the Chester Lunatic 

 Asylum. The wires are placed about a quarter of an inch apart, and 

 the piaster forms an adhesive and serviceable mass, which is even on 

 both sides. The wire is galvanized, or japanned, to prevent corrosion. 

 Not only ceilings, one would think, but thin partitions and walls in 

 general, might be wired instead of lathed, and the risk of fire would 

 thus be greatly diminished by a process not at all costly. London 

 Builder. 



