_Wood Turning._--To this ancient art Blanchard added, in 1819, his very ingenious and important improvement for turning irregular forms. A few efforts at irregular turning had been made before, but in the arts generally only circular forms had been turned. With Blanchard’s improvement, patented January 20, 1820, any irregular form, such as a shoe-last, gun-stock, ax-handle, wheel-spokes, etc., could be smoothly and expeditiously turned and finished in any required shape. In the ordinary lathe the work is revolved rapidly, and the cutting tool is held stationary, or only slowly shifted in the hand. In the Blanchard lathe the work is hung in a swinging frame, and turned very slowly to bring its different sides to the cutting action, and the cutting tool is constructed as a rapidly revolving disk, against which the work is projected bodily by the oscillation of the swinging frame, to accommodate the irregularities of the form. In order to do this automatically, a pattern or model of the article to be turned was also hung in the swinging frame, and made to slowly revolve and bear against a pattern wheel, which, acting upon the swinging frame carrying the work, caused it to advance to or recede from the cutting disc exactly in proportion to the contour of the model, and thus cause the revolving cutters to cut the block as it turns synchronously with the model, to a shape exactly corresponding to said model. [Illustration: FIG. 247.--BLANCHARD LATHE.] In Fig. 247 is shown a perspective view of Blanchard’s lathe, as patented January 20, 1820. H is a swinging frame, carrying the model T of a shoe last, and a roughed-out block U, partly converted into a shoe last. A sliding frame, fed horizontally by a screw, carries a pattern wheel K, that bears against the pattern T, and a rotary cutter E, acting against the roughed-out block U. The revolving disk-shaped cutter E is rotated by a pulley and belt from a drum, which latter is made long enough to accommodate the travel of the frame. The pattern T and block U are advanced to contact respectively, with pattern wheel K and cutter E by the swinging action of frame H, and as the pattern T and block U are slowly revolved, the travel of T against K is made to react on frame H and regulate the advance of U against E, with the result that the rough block U is cut to the identical shape of the pattern T. Among modern developments in this art may be mentioned the patents to Kimball, No. 471,006, March 15, 1892, and No. 498,170, May 23, 1893, the latter showing ingenious means whereby shoe lasts of the same length, but varying widths, may be turned. A polygonal-form lathe is shown in patent to Merritt, No. 504,812, September 12, 1893; a multiple lathe in patents to Albee, No. 429,297, June 3, 1890, and Aram, No. 550,401, November 26, 1895; a tubular lathe in patent to Lenhart, No. 355,540, January 4, 1887; and a spiral cutting lathe in patent to Mackintosh, No. 396,283, January 15, 1889.