Hatfield, Robert Griffith, 1815-1879. [from old catalog] · New York & London, Wiley and Putnam · leaf 63
arc, j i ; upon h and/, with h a for radius, describe the arcs, j k and I i; this willcomplete the figure. This is a very near 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 process,… … 122.—To draw a tangent to an ellipsis. Let abed, {Fig:88,) 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; then5 r will be the tangent required.
Carpentry · Architecture
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