Essentials of drafting; a text and problem book for apprentice, trade and evening technical schools (1918)
Svensen, Carl L. (Carl Lars), 1884- · New York, D. Van Nostrand company · leaf 36
in Figs.46 and 47, where the pointsof tangency are marked T. The Ellipse. — An ellipse(Fig. 48), is a curve formedby a point moving so thatthe sum of its distances fromtwo fixed points is a constant.Each of the two points Fi andF2 is called a focus. The ^^ longest line, AB, drawnthrough the center… … 20 ESSENTIALS OF DRAFTING
Mechanical drawing
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