What came between slipsticks and calculators?

"The Curta is a precision calculating machine for all arithmetical operations. Curta adds, subtracts, multiplies, divides, square and cube roots... and every other computation arising in science and commerce... Available on a trial basis. Price $125."

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From an advertisement in the back pages of Scientific American in the 1960s. The cost is nearly $700 in 2002 dollars -- about the same price as Mathematica. Curtas sell on e-Bay for thousands of dollars these days.

I found one of these while cleaning out a drawer in an old piece of furniture inherited from my husband's family. Its purpose was a mystery, until an article in Scientific American on the history of these calculating machines. What did we do before calculators and symbolic algebra code? There was paper and pencil, log tables, slide rules (based on logarithmic principles and called a slipstick by the geeks of the time!) and calculating machines based on rotating drums. The most sophisticated of these mechanical computers was the Curta. Developed by Curt Herzstark while he was imprisoned in Buchenwald by the Nazis, this small drum shaped calculator was capable of 11 digit accuracy. For comparison, a slide rule has only 3 digit accuracy and a TI-83 graphing calculator has 14 digit accuracy (even though it only displays 10!).