The Curta is a small mechanical calculator developed by Curt Herzstark. The Curta’s design is a descendant of Gottfried Leibniz’s Stepped Reckoner and Charles Thomas’ Arithmometer.
Accumulating values on cogs, which are added or complemented by a stepped drum mechanism. It has an extremely compact design: a small cylinder that fits in the palm of the hand.
(images credit: Helmut G. Ayen)
It was invented by Curt Herzstark (1902-1988). Looking something like a small coffee or pepper grinder.
(image credit: Dave Hicks)
This incredible high-precision unit fit in the palm of one hand and could perform addition, subtraction, multiplication, and division.
The digits shown in the black area on the top of the calculator represent the accumulator, which contains the current ongoing result.
Curtas were considered the best portable calculators available until they were displaced by electronic calculators in the 1970s.