. The practical draughtsman's book of industrial design, and machinist's and engineer's drawing companion: forming a complete course of mechanical, engineering, and architectural drawing . r burr stones—all excavated from the valley of the Marne. The ingenious and important contrivance of the antifrictioncurve, by Mr. Schiele, has found an important application in thegrinding surfaces of millstones, in which it has introduced a strikingdeparture from old-established principles. The inventor was ledto the consideration of this system of working surfaces by theirregularities of wear in the commo
. The practical draughtsman's book of industrial design, and machinist's and engineer's drawing companion: forming a complete course of mechanical, engineering, and architectural drawing . r burr stones—all excavated from the valley of the Marne. The ingenious and important contrivance of the antifrictioncurve, by Mr. Schiele, has found an important application in thegrinding surfaces of millstones, in which it has introduced a strikingdeparture from old-established principles. The inventor was ledto the consideration of this system of working surfaces by theirregularities of wear in the common conical plugged the truncated cone of the stopcock plug to be divided BOOK OF INDUSTRIAL DESIGN. 105 into a series of infinitely short lengths, he proposed to take a moreobtuse cone for each larger portion, and in such progression, thatit would require equal pressure for every portion of the surface tocause a uniform sinking of the plug in the course of wear. Thecontour thus obtained is of a peculiar curve, as shown in fig. main feature of the generating curve for such a surface, is theequality of all tangents drawn from the curve surface to the axis;. Fig. 3. hence the use of the simple instrument illustrated by fig. 2. Thiscontrivance consists merely of a straight brass wire, a, jointed atone end by a pin to the upper surface of a small wooden slider, B,which is hollowed in the centre to receive the tip of the finger indrawing a curve. A small drawing-pen, c, ingeniously formedout of a slip of steel bent over the wire, A, and screwed to a brassbush, so as to form two broad nibs, is arranged to slide from endto end of the wire, being adjustable at any point by stiff friction,caused by a spring, which, fitting a groove in the wire, retains thevertical position of the pen. In drawing a curve, the rod or wirecarrying the pen is set at right angles with the slider, b, which isdrawn in a right line along the edge of a ruler, whilst the wirecarrying th
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Keywords: ., bookcentury1800, booksubjectdecorativearts, booksubjectdrawing
