Jaap Scherphuis | The Rapid Computer @jaapsch2 | Uploaded December 2018 | Updated October 2024, 2 hours ago.
The Rapid Computer was made between 1905 and about 1915. It has 9 sliders with toothed racks that drive the number wheels in the 9-digit register.

For more information about this and the rest of my collection of mechanical calculators, see my site:
jaapsch.net/mechcalc

0:00 Introduction
0:29 History
1:43 Addition
2:47 Clearing
3:35 Further history
3:57 Outro