330

HISTORY OF ENGINEERING. Book I.

sistcil of fewer apartments, there being only a coal vault, a dwelling room, pipe room,and lantern.

In the larger one there was a coal vault, a smith’s shop, and machine for hoisting the

coals. A vacant room, a dwelling room,with two fireplaces, to be used according tothe direction of the wind, two chambers, oneover the other, a pipe room, wherein weretwo of the eight pipes that conveyed air fromthe external hopper mouths to the receptacle,which was lined with thick plate iron; thebottom being stone, when the door was shut,the air ascended through a large funnel andthe hearth to the fire-grate.

The flame was seen in every direction,through the windows of the lantern, andthe smoke was collected in its passage throughthe decagon conical roof, composed of tenKlland edge flag-stones, and then through thecopper funnel at the top.

The coals to supply the fire were drawn upin a tub through an opening by means of aroll, wheel, pinion, and wrench. A rope fromthence, ascending through all the floors, passedover a barge pulley suspended from the roof,and thence downwards through the hole inan arch to a large square wooden pipe, ter-minating in a hopper mouth, proper forreceiving the burthen.

The ashes and hot cinders, passing throughthe grate, fell into the bottom of the recep-tacle, and by heating the air therein pro-moted a sufficient draught in the calmestweather, which could be augmented andregulated, when there was a breeze, as any ofthe air-pipes could be enclosed at pleasure.The ashes and cinders were thrown into a

Fig. 323.

srt’BN point

Fig 320.

SECTION OF LKUntlOl'iE.