Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ..draughtsmen .. . 77. The reverse curves Xig-. SI. M n /o yy ^v^ / m „¥? \ c, N on the mouldings may be drawn with the irregular curve, (see Art 68);or, if composed of circular arcs to be tangent to vertical lines, by the follow-ing construction: — Let 31 and iV be the points of tangency on the verticals Mm. and Nn,and let the arcs be tangent to each other at the middle point of the lineMK Draw 3In and Nm perpendicular to the vertical lines. The centres, cand c,,
Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ..draughtsmen .. . 77. The reverse curves Xig-. SI. M n /o yy ^v^ / m „¥? \ c, N on the mouldings may be drawn with the irregular curve, (see Art 68);or, if composed of circular arcs to be tangent to vertical lines, by the follow-ing construction: — Let 31 and iV be the points of tangency on the verticals Mm. and Nn,and let the arcs be tangent to each other at the middle point of the lineMK Draw 3In and Nm perpendicular to the vertical lines. The centres, cand c,, of the desired arcs, are at the intersection of 31 n and Nm by per-pendiculars to 31N from x and y, the middle points of the segments of The light is to be assumed as coming in the usual direction, i. e.,descending from left to right at such an angle that any ray would be projected on the paper at anangle of 45° to the horizontal. In Fig. 43 several rays are shown. At x, where the light strikes the cylindrical portion mostdirectly—technically is normal to the surface—is actually the brightest part. A tangent ray st givest,
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Keywords: ., bookcentury1800, bookdecade1890, booksubjec, booksubjectlettering
