Accession No
6156
Brief Description
mechanical calculator, Curta Type 1, by Contina AG, Liechtenstein, 1969 (c)
Origin
Liechtenstein; Mauren
Maker
Contina Ltd.
Class
calculating
Earliest Date
1969
Latest Date
1969
Inscription Date
Material
plastic; metal; rubber
Dimensions
Diameter 68mm; height 123mm (cylindrical case) Diameter 53mm; height 107mm (calculator)
Special Collection
Hookham collection
Provenance
Donated in or before 1987.
Inscription
‘System Curt Herzstark
Made in Liechtenstein
by Contina Ltd Mauren
Type No 76139’ (bottom of calculator)
Description Notes
Curta type I calculator, 1948.
Black-painted metal cylinder with plastic ends.
Crank operating handle at top. When this is in its lower position, the number entered on the will be multiplied by a positive number; when it is raised, a red band around its base will be seen and the multiplicand will be negative. Handle can only be turned in a clockwise direction, and only when a full turn is completed is the calculation complete.
Clearing lever underneath operating handle. When this is locked into position and the carriage is raised, the lever can be rotated past the result dial and/or the counter dial to reset them.
Dials underneath lever. The black dial has 11 digits and shows the result of the calculation. The silver dial has 6 digits and shows the multipicand (i.e. the number that the number entered on the side has been multiplied by).
The upper knurled ring below dials is known as the carriage. Lifting this allows it to be rotated. This changes the number ointed to by the white arrow, which indicates the magnitude of the multiplicand. When at position 1, the number on the side is multiplied by 1, when at 2 by 10, when at 3 by 100, etc.
Beneath the carriage are 8 sliding knobs with which to set the number to be multiplied. The slide on the far right is for units, the next to the left for tens, etc. When the slide its at its upper most position, the number displayed above is 1, when is slid down and locks into the next position the number is 2, etc.
Original enamelled metal screw-top storage case.
Original box containing instruction booklet and counter or quotient dial.
References
Events
Description
The Curta calculator is one of the smallest mechanical calculating machines ever made: in fact, a pocket calculator. It was developed by Curt Herzstark, an Austrian who worked on the plans whilst in a Nazi concentration camp during the Second World War. His captors encouraged him with the aim of presenting the device to Hitler to celebrate victory in the war. In 1945 Americans liberated the camp and Hertzstark moved to Liechtenstein to manufacture his product. By 1973 they were discontinued due to the success of the electronic pocket calculator, having sold around 140,000 machines.
Curt acheived this four function calculator by inventing the complemented stepped drum to perform calculations. Previously, all mechanical calculators manufactured in large numbers had been based on either a stepped drum (traced back to Leibniz) or a pinwheel (introduced by Odhner). The term ‘complemented’ refers to the fact that it uses an algorithm to turn subtractions into additions, and a ‘stepped drum’ is a cylindrical driving element with protruding ribs of various lengths.
Here is an example calculation:
133x89 = ?
- reset the counters (by lifting the carriage and turning the clear handle) and set the carriage in position 1
- set the number 133 using the setting knobs
- pull up the crank so that it is in subtractive mode and make one revolution, which calculates 133x(-1)
- set carriage in position 2 and, with the crank still pulled up, make a subtractive revolution, which calculates 133x(-10)
- set carriage in position 3, push crank back in the position for addition and make one revolution, which calculates 133x100.
A check is provided by the revolution counter, which shows 89, so we did multiply 133 with 89. The result 11837 can be read in the result counter. What has been calculated is 133x(-11+100) and that is equal to 133x89; this was done in 3 revolutions instead of 17.
29/08/2007
Created by: S Davis on 29/08/2007
FM:46619
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