This little gem was the world's best mechanical calculator up until modern electronic ones came on the scene. It rivalled large slide rules in accuracy and could be much faster. Interestingly, it was invented by a prisoner in a concentration camp who was kept alive just to work on his invention.

Curta calculator - Wikipedia, the free encyclopedia

That is a great invention and must say that I have never heard of the "Curta". It would be interesting to see how one worked hands-on.
I wonder if that CC prisoner had worked on a prototype before imprisonment. If not, he sure had a strong mind to be able to work on such a project in horrendous circumstances.

Curt Herzstark - Wikipedia, the free encyclopedia

There's the answer...:-)

Curtas are actually pretty easy to use once you get used to them. They have a series of little slides on the side you position for the operation to be performed and numbers used. You then crank the top handle until things line up at the answer point. It is sort of a mechanical circular slide rule.
The Curta was very popular with rally crews, that's where I learned about and used them years ago....pro rally running "B" cars.
There was a lengthy article in Scientific American a few years ago on the Curta too. I'll see if I can find it.

Thanks TA, never heard of, and have no sensible use for it, but I'm now feeling an irresistible urge to own one.
From that Wiki Page's links this seems to be the most 'full on' site:
The CURTA Calculator Page
With a truly baffling Simulator:
Curta-Simulator,
I'm going to have to work this out .


Having just checked some prices I suspect I may be sticking with the simulator...

Cheers,
Adam.

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It's only the Internet.

that's pretty neat!
i had never heard of this before now!
thanks!

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Scott