The American house carpenter: a treatise upon architecture, cornices and mouldings, framing, doors, windows and stairs. Together with the most important principles of practical geometry (1852)
Hatfield, R. G. (Robert Griffith), 1815-1879 · New York, J. Wiley · leaf 65
122.— To draw a tangent to an ellipsis. Let abed, {Fig.88j) be the given ellipsis, and d the point of contact. Find thefoci, [Art. 115,)/and/, and from them, through d, draw/e andf d; bisect the angle, [Art. 77,) e d o, with the line, 5 r ; thens r will be the tangent required. … c Fig. 89. 123.—An ellipsis with a tangent given, to detect the pointof contact, hetagbf, {Fig. 89,) be the given ellipsis and tan-gent. Through the centre, e, draw a h, parallel to the tangent jany where between e and/, draw c d, parallel to ab ; bisectcdin0 ; through o and e, dmwfg; then g will…
Carpentry · Architecture
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