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 YEAR: 1847
 COUNTRY: England
Click here for further information on our rarity scale RARITY: Unknown
Difference Engine #2 Printout

A view of the vintage Difference Engine #2 Printout an important part of computer history
The Difference Engine #2 was designed by Charles Babbage between 1847 and 1849. Despite decades of effort, he never managed to build any of his Difference Engine or Analytical Engine designs and he died in 1871. The London Science Museum (LSM), in order to celebrate the 200 year anniversary of Babbage's birth, decided to attempt to build the Difference Engine #2 based on Babbage's original plans and drawings. They used the technology available during his life and, after two years of work, completed the computing unit in June 1991, just in time for the celebration.

The computer was designed to produce error-free mathematical tables for use in astronomy and navigation. The tables used by the British Navy for navigation were extensive and, because they were calculated by hand, contained errors. These errors could result in ships going way off course. Babbage hoped to automate the the tables and, in doing so, remove all errors.

According to the Encyclopedia Britannica, "Up until then calculations were rarely carried out to more than 6 digits; Babbage planned to produce 20- or 30-digit results routinely."

Although, the computer was completed in 1991, the printing mechanism part of it was not completed until the year 2000. This is a printout from the first Difference Engine #2 ever built. (The LSM finished building a second machine in 2007.)

The printout was given to Dr. Pearson by one of the curators at the LSM in the summer of 2005. It consists of 18 thirty-digit numbers. The printout measures 11 inches long by 5 1/4 inches in wide. It was probably printed in the year 2000.

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Click on any of the images below to see the slideshow.
Printout from Difference Engine #2