Detail, Babbage's Difference Engine No. 2
A difference engine is a special-purpose mechanical digital calculator, designed to tabulate polynomial functions. Since logarithmic and trigonometric functions can be approximated by polynomials, such a machine is more general than it appears at first.
Difference Engine No 2 was designed from 1847-1849 by British computing pioneer Charles Babbage (1791-1871), but was never built in his lifetime. To celebrate the 200th anniversary of the birth of Charles Babbage, the Science Museum in London undertook construction of the engine in 1989-1991. It consisted of 4,000 parts, weighing three tonnes. The device is 2.1m high, 3.4m long, and 0.5m wide. The separate (4,000 more parts, two tonnes) printing mechanism was completed in 2000. Built to tolerances known to be achievable in Babbage's day, both worked perfectly.
The photo above is actually of a second Difference Engine No. 2, currently under construction at the Science Museum for an American customer.
Detail, Babbage's Difference Engine No. 2
A difference engine is a special-purpose mechanical digital calculator, designed to tabulate polynomial functions. Since logarithmic and trigonometric functions can be approximated by polynomials, such a machine is more general than it appears at first.
Difference Engine No 2 was designed from 1847-1849 by British computing pioneer Charles Babbage (1791-1871), but was never built in his lifetime. To celebrate the 200th anniversary of the birth of Charles Babbage, the Science Museum in London undertook construction of the engine in 1989-1991. It consisted of 4,000 parts, weighing three tonnes. The device is 2.1m high, 3.4m long, and 0.5m wide. The separate (4,000 more parts, two tonnes) printing mechanism was completed in 2000. Built to tolerances known to be achievable in Babbage's day, both worked perfectly.
The photo above is actually of a second Difference Engine No. 2, currently under construction at the Science Museum for an American customer.