Practical draughtsmen's work, with numerous engravings and diagrams (1903)
Hasluck, Paul N. (Paul Nooncree), 1854-1931, ed · Philadelphia, D. McKay · leaf 87
and axis, mark off the semi-diameter and the height, andcomplete the rectangle. Divide the semi-diameter into twenty-equal parts by vertical lines, and number them as shown. Nowplace a straight-edge or the side of a set-square in line with thelower left-hand corner of the figure and the point… … SEMI BASE OF PARABOLA Fig. 141.—Parabola Constructed by Continuous Tangents. divisions ; and so on until point 19 is reached, when it will befound there is only one division to draw the last line across topoint 20. By this means a parabola wdll have been formedapproximately correct, but actually…
Mechanical drawing
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer03inte-607-361.webp)
