Appleton's cyclopædia of drawing, designed as a textbook for the mechanic, architect, engineer, and surveyor (1866)
Worthen, William Ezra, 1819-1897, [from old catalog] ed, Appleton, firm, publishers, New York. (1866. D. Appleton & co.) [from old catalog] · New York, D. Appleton and company · leaf 215
Fig. 273. A, whose edge s f is an arc of the pitch circle, is fixed upon B, whoseedge is an arc of the extreme circumference of the wheel, the space s s be-tween those edges being in breadth equal to the length of the teeth from
