Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition (1914)
Horsburg, E. M. (Ellice Martin), Napier Tercentenary Exhibition (1914 : Edinburgh, Scotalnd) · London : G. Bell · leaf 104
Fig. 5.—Metal Disc. … Fig. 6.—Covering Disc. The Odhner toothed wheel consists of two parts, a metal disc with slots anda thin covering disc with a raised centre, attached so as to turn on the other(figs. 5 and 6). In the slots of the metal disc lie steel fingers with a projecting catch—the movable teeth of the toothed…
