# Difference machine

**a difference machine** (English. *difference engines*) is a mechanical computer for the release of polynomialer functions.
Since each constantly differentiable function can be approximated by a polynomial, so a machine is clearly more versatile applicable, than it has first the appearance.

## Table of contents |

## history

First of these devices became 1786 of J.H. Mueller developed, it was however never built.A further forerunner of an adding machine was Leibniz ' relay roller machine from that 17. Century, which was inspired of the Pascaline for its part, which had developed Blaise Pascal 1642. The concepts came into oblivion. 1822 was revived it by Charles Babbage. A prototype,square functions to compute, 1832 knew were finished placed. This machine used the decimal system and by the rotation of a crank was propelled. The British government financed the project first, stopped the support however later.

## function mode

thoseDifference machine could only add. Subtraction, multiplication and division as well as more complex computations could be accomplished only to that extent, as far as it is possible to attribute it by mathematical tricks to a series of additions.

After Babbage the concept of its clearly more versatile analytic machine develops, turned he had again to the difference machines and sketched themselves between 1847 and 1849 an improved model, *the Difference engine No. 2*. This could not be carried out however at that time because of the insufficient technical possibilities. It was appropriate for it, polynomials7. To compute degree on 31 places. Only between 1989 and 1991 became in *London Science museum* the Difference engine No. 2 functionally copied. 2000 were finished placed the printer likewise sketched by Babbage. Both devices work perfectly.

Livelyby Babbages drafts built George and Edward Scheutz in Stockholm from 1834 to 1858 different difference machines. One of it was sold to the British government.