Appleton's cyclopædia of drawing, designed as a textbook for the mechanic, architect, engineer, and surveyor (1866)
Worthen, William Ezra, 1819-1897, [from old catalog] ed, Appleton, firm, publishers, New York. (1866. D. Appleton & co.) [from old catalog] · New York, D. Appleton and company · leaf 134
he position A K the generating line isprojected in its actual length, and that at the position C W its verticalprojection is the point C. The same remark applies to the generatrix oftlie scc(>nd helix. The parts of both curves which are visible in the ele-vation may be easily determined by… … GEOMETRICAL PKOJECTION. 101 of a sphere whose radius is a C describes a liclix, which is projected onthe vertical pLane in the curve A C E J. After determining as above the various points A, B, C, D , in this curve, draw from each of these points as centres, circles with the radius a C ; the…
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