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 367
n P actuated by the summation wire movesup and down in front of an upright strip of paper travelling horizontally andconstantly unwound from a roll by means of an electric motor, which at thesame time drives the harmonic wheels. In order that the periodic time of thelatter may be variable at will,…
