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 217
circular edge mayaccurately coincide with the circumference of the arc el el. Ji. portion ofa circular plate D is next provided, of the same radius which it is proposedto give to the generating circle : this plate has a fine tracing point atj?inserted into it, and projecting slightly from its under… … rig. 276. by the clearance ^^licli it is desired the teeth should have, may be equalto the pitch, the generating circle D is made to roll upon the convex edge of B; meantime the point at p willtrace upon the board the curve ofthe faces of the tooth, having causedthe point to coincide…
