Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 48
CONSTRUCTION OF GEOMETRICAL PROBLEMS. 31 … Fig. 101. inside the loop, the point of the pencil will coincide with C. Move the pencilround, keeping the loop evenly stretched, and it will describe an ellipse. Thisconstruction follows the definition above given of an ellipse, that the sum ofthe distances of every point of the curve from the…
Mechanical drawing
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