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 234
i^LATE XXII. 19fl … DEAWING OF MACHINERY. 181 fig. 2 tliey are represented by lines drawn throiigli the various pointsfound as above for the outer extremities of the teeth, and convergingtowards the common apex S ; while the centre-lines of the exterior andinterior extremities themselves all tend to the points o and o…