Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 20
Fig. 4. … In the following problems, unless otherwise implied or designated, wherelines are mentioned, straight lines are intended. If a straight line moves sideways in a single direction, it will sweep over asurface which is called a plane. All drawings are projecHons on planes ofpaper or board. Two lines…
Mechanical drawing
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