The American house-carpenter; a treatise on the art of building, and the strength of materials (1873)
Hatfield, R. G. (Robert Griffith), 1815-1879 · New York : J. Wiley · leaf 68
Fig. 88. 122.— To draw a tangent to an ellipsis. Let abed, (Fig.38,) 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, sr; thens r will be the tangent required. … Fig 89 123.—An ellipsis with a tangent given, to detect the pointof contact. L,etagbf, (Fig. 89,) be the given ellipsis and tan-gent. Through the centre., e, draw a b, parallel to the tangent;any where between e and/, draw c d, parallel to a b ; bisect c d ino ; through o and e, draw f g ; then g…
Carpentry · Architecture
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