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Drawn Pipes — Burr’s Plan—Window Lead. [Book V.

tion of raetal was left along the seam. The ancient pipes figured byMontfaucon have a similar projection.

The plan of drawing leaden pipes through dies like hollow wire wasfirst proposed by M. Dalesme, in the Transactions of the French Academy of Sciences , in 1705. It was subsequently brought forward by M. Fayollein 1728; but it was not tili 1790 that such pipes were made. In that year,Mr. Wilkinson, the celebrated Ehglish iron master, took out a patent fordrawing them, since which period they have become general in England,France , and the U. States.—(See Reper. of Arts, Ist series, vol. xvi.)

In 1820, a singulär mode of making leaden pipes was patented in Eng-land by Mr. T. Burr. A large and very strong cast iron cylinder, in whicha metallic piston is made to work, is secured in a vertical position. Tothe underside of the piston a strong iron rod is fixed, its lower end beingcut into a screw or formed into a rack for the convenience of forcing thepiston up, either by means of a steam engine or any other suitable firstmover. To the upper side of the piston is secured a polished cylindricalrod, rather longer than the cylinder, and of the same diameter as the boreof the pipe. The cylinder forms a mold in which the pipe is first cast,and this rod is the core. The bottom of the cylinder may be open; butthe top is strongly closed, with the exception of a circular and polishedopening at the centre, of a size equal to the external diameter of the pipe.Suppose the piston now drawn down to near the bottom of the cylinder,the upper end of the polished rod will stand a little above the circularopening, and an annular space will be left between them equal to therequired thickness of the tube. The cylinder is tben to be filled withfused lead through an opening at the top, (which is to be stopped up bya screw-plug or any other device,) and as soon as the metal begins toassume the solid state, the piston is slowly raised ; this necessarily forcesthe lead through the annular space in the form of a tube, which is thenwound on a reel as fast as formed.

Various cylinders are employed according to the different sized tubes.For half inch pipe, one 18 inches long, six or seven inches internal diame-ter, and the sides three or four inches thick would be required. Plateswith openings of different sizes may be adapted to one cylinder. Theymay be made to slide in recesses cast in the top.

This mode of forming leaden tubes is the same in principle as that bywhich some of earthenware have been made : the clay being put into asquare and close trunk, is forced by a piston through an annular space,adapted to the thickness and bore of the tubes required. At first sightthe process appears difficult. It also seems stränge that solid lead canthus be squeezed through an aperture into the form of a tube ; but it shouldbe remembered that this metal is extremely soft when heated to near thefusing point; and that the mode only differs from that of making claypipes in requiring a greater force. Tubes made in this way are in generalmore solid than others. This arises from the large body of metal of whichthey are formed being poured while very hot into the cylinder, so thatthere is little danger of flaws or fissures. These pipes may also be madein much greater lengths than by any other plan. A manufactory of themhas recently been established in Philadelphia. —(See Repertory of Arts,for 1820, vol. xli, p. 267.)

From the quantities of pipes used of old, it appears singulär that theart of drawing them was not discovered, especially as the Tire-Plomb orglazier’s vise for drawing “ window lead” is of ancient date—a most beau-tiful machine, and one far more ingenious and interesting than the draw-bench; one too by which lead is worked at a single Operation into very