Elements of drawing
A 1912 mechanical drawing textbook by George F. Blessing and Lewis A. Darling, published by John Wiley & Sons in New York for engineering students learning drafting practice. The plates are line exercises on ruled grids: heavy tapered strokes, arrowed dimension lines, fraction numerals, dashed construction lines and lettered guide marks, useful as ready-made grid backgrounds, arrow and dimension-line vocabulary, and hand-drawn geometric figures.
