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
be the arc, j i ; upon h and/, with h k for radius, describe the arcs, j k and I i ; this willcomplete the figure. This is an approximation to an ellipsis ; and perhaps nomethod can be found, by which a well-shaped oval can be drawnwith greater facility. By a little variation in the piocess,… … 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.
Carpentry · Architecture
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