Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 139
point. If from every point of an indefinite straight line, A B (Fig. 252), placed inany manner in space, perpendiculars be let fall on a plane, L M N 0, whoseposition is given, then all the points in which these perpendiculars meet theplane will form another indefinitestraight line, a t: this line…
Mechanical drawing
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