Dr. Dobb's Journal July 1998

Paradigms Past

It seems like a simple question: Who invented the calculator? But questions of paternity are often tricky. According to the U.S. Patent Office, the inventor was a bank clerk in St. Louis named William Seward Burroughs, in 1886. Burroughs, the namesake and ancestor of beat author William S. Burroughs, built both a calculator and a company to sell it (American Arithmometer Company, later Burroughs Adding Machine Co.).

But Burroughs was beaten to the punch (by fully 66 years) by one Charles Xavier Thomas, Thomas of Colmar to his friends, who built the first commercial mass-produced calculator in 1820. It could add, subtract, and multiply, and, if you helped it a little, even divide. It took up most of a desktop, and continued to be sold for 90 years.

Tom had got the idea, though, from a 17th century invention of Gottfried Wilhelm von Leibniz. Leibniz's Stepped Reckoner was definitely a calculator: It added, subtracted, and did multiplication by repeated addition and shifting. Although Leibniz was an early booster of the binary system, his machine was decimal.

But Leibniz wasn't first: Three years before he even planned his machine, a Brit named Samuel Morland had built a machine for toting up (decidedly nondecimal) British currency.

Was Morland the first? Nope. Both he and Leibniz had merely expanded on an invention of Blaise Pascal. The Pascaline, built in 1642 for Pascal's tax-collector dad, was (aha!) the first digital adding machine (and the first digital business machine). Pascal sold about a dozen of them. But the story doesn't end there. Still earlier, in 1624, a fellow named Schickard had built a Calculating Clock that could add and subtract. If you really needed to multiply, you could use the slide rule affixed to the front.

And even earlier, sometime in the 1500s, an artist drew some (recently discovered) sketches for a mechanical device that would add and subtract numbers. When a machine was built based on these sketches, it actually worked.

The name of this artist, arguably the true inventor of the calculator, was Leonardo da Vinci. Another Leo.

-- M.S.