76

CONSTRUCTION OF THE BUILDING.

Morticing ma- To facilitate the putting together of the sash-frames and sash-bars, considerabledime employed. ugc wag ma( q e 0 f a machine fo r making mortices and tenons, patented by Messrs.Furness & Co., of Liverpool.

Fig. 30.

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The making; of While these various machines were busily operating in the preparation of theie g ass. necessary framework to receive the glass, Messrs. Chance, Brothers, & Co., ofSmethwick, near Birmingham , to whom the contract for its supply had been com-mitted, were not less actively employed. The large size of the sheets required(4 feet 1 inch by 10 inches), and the extraordinary short time within which theimmense quantity necessary had to be supplied, demanded the employment ofnumerous additional hands, and workmen had to be sought for from abroad toassist in the completion of the order within the requisite time. The mode ofmanufacturing the description of glass employed is a great improvement on theold system of crown-glass making; as by it the variation of the substance occa-sioned by the thickness of the glass, as it approaches the bull’s eye, is completelyavoided. In the manufacture of sheet glass, the workman, having taken up alump of glass on the end of'his pipe, alternately blows, swings his ball of glass toand fro, and rolls it upon a metal table until it assumes the form of a longcylinder; the ends being then taken off and the cylinder cut in the directionof its length, the sheet of glass falls down, is flattened to a perfectly true faceand is then trimmed off and finished.

Progress made in During the preparation of the materials necessary to commence the construc-ted r °° f tion of the Paxton roofing, active progress had been made in the framing of thewrought-iron trusses requisite to span the central 72-feet nave, and the 48-feetavenues on ea.ch side of it. A. steam-engine of 6-horse power gave motion tobv means of drilling, punching, and cutting machines, represented in figs. 31 and 32; byfn^iSdStoS- means of these, the necessary pieces of bar-iron were adjusted to their requisitemachines ; i engt hs. The holes for riveting having been marked upon them with templates,were punched out, and any larger perforations necessary for extra-sized rivets,drilled. The various parts, thus prepared for combination, were then arrangedupon platforms, and the holes in the various portions being made to correspond,