Site.Adall1910 History
Hide minor edits - Show changes to markup - Cancel
John Wolff describes this calculator rather neatly as follows:
John Wolff describes the Adall calculator rather neatly as follows:
- Single column, addition only
- Direct operation by stylus
- Dimensions: 195mm diameter x 6mm thick, case 210 x 210 x 28mm
- Weight: calculator 190g, with case 440g
- Manufactured: Adall Company, Birmingham, England, 1910–1920s
John Wolff describes this calculator well as follows:
John Wolff describes this calculator rather neatly as follows:
The mechanism consists only of two concentric discs. The outer (setting) disc of 0.8mm aluminium forms the base of the machine. A ring on the back is slipped over the middle finger so that the machine can be held flat against the palm of the hand. The outer disc is marked anti-clockwise from 0 to 100, with the tens highlighted. The inner (results) disc is marked from 0 to 100, corresponding to the 100 teeth around its outer edge. A flat cross-bar runs from the centre to the zero position on the outer disc to act as a stop. To add, the stylus is placed in the tooth opposite the desired number on the outer setting disc, and the inner disc is pulled clockwise until the stylus reaches the stop. The result appears in the window in the cross-bar.
John Wolff describes this calculator well as follows:
The mechanism consists only of two concentric discs. The outer (setting) disc of 0.8mm aluminium forms the base of the machine. A ring on the back is slipped over the middle finger so that the machine can be held flat against the palm of the hand. The outer disc is marked anti-clockwise from 0 to 100, with the tens highlighted. The inner (results) disc is marked from 0 to 100, corresponding to the 100 teeth around its outer edge. A flat cross-bar runs from the centre to the zero position on the outer disc to act as a stop. To add, the stylus is placed in the tooth opposite the desired number on the outer setting disc, and the inner disc is pulled clockwise until the stylus reaches the stop. The result appears in the window in the cross-bar.