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 105
Fig. 8.—The Setting Mechanism. … T-TT Fig. 9.—Counting Mechanism. In all of them, however, there persists this defect, that in order to set thenumber of teeth on the toothed disc, the covering disc must be turned directly.In doing so the hand setting the figures must be continually raised, as a resultof which the arm tires, and…
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer04inte-458-228.webp)
