The Curta was a small handheld mechanical calculator
that used no electric
parts. Curta's were capable of addition
It was invented by Curt Herzstark of Austria while he was imprisoned in a Nazi concentration camp. The camp was liberated in 1945, and the Curta was in production by 1947.
By 1949 production was 300 units per month increasing to 1000 per month by 1952. The last Curta was made in 1970, there were two different models produced. A total of about 140,000 units were produced.
The first Curta was capable of 11 digits of precision, the newer model 15 digits. The larger Curta was 2.6 inches by 3.6 inches and weighed 12.5 oz. Looking like a small cylinder with sliding levers around the middle and a crank on top. Above each sliding lever is a window that shows the number input by moving the slide. On top with the crank were a revolution counter, an output dial that shows the results, and a reset lever.
The Curta died out around 1972 because it was unable to compete with the the pocket calculator.
The Curta was a beatifull little machine, check out the photos at: http://www.vcalc.net/cu.htm