Wow! This is amazing!

The Difference Engine was an accurate mechanical calculator designed by Charles Babbage in the 1840s, but was never built in its inventor’s lifetime. Here, its modern builder explains how it works.

Charles Babbage completed plans for an elaborate, all-mechanical calculator in 1849. His Difference Engine #2 was so complicated, with more than 8,000 separate parts, that it was never built during his lifetime. But now, thanks to the efforts of dedicated, historically-minded engineers at the Computer History Museum in Mountain View, California, plus a generous donation of cash from Microsoft gazillionaire genius Nathan Myhrvold, Babbage’s Difference Engine is on display in Silicon Valley.

Babbage’s Difference Engine No. 2

It works. The five-ton bronze, steel and cast iron contraption is operated by a crank handle and can calculate the results of elaborate trigonometric and logarithmic functions with 31 digits of precision. What’s more, it has a printer which stamps the results of its calculations on paper and on a plaster tray, which could be used to create lead type for printing books of mathematical tables.

The Difference Engine opens to public viewing on May 10 and will be on display at the museum for a year, after which it will be transported to Myhrvold’s private collection.