First mechanical calculators
Blaise Pascal, Samuel Morland, Gottfried Wilhelm Leibniz
Pascaline (XVII century)
The addition and subtraction machine, built in 1645 by Blaise Pascal (independent of the Schickard clock). The setting device consisted of discs moved by a pin
About 50 units were produced. Eight of them (and a lot of copies) have survived. The photo shows Pascalina from the Milan museum, dedicated to monetary calculations.
Morland’s tools (without transfers)
A pocket-sized addition and subtraction machine from 1662
A machine that uses Napier's dials for
multiplication (Florence museum)
The Leibniz wheel
In 1670 Gottfried Wilhelm von Leibniz described the concept of a calculating
machine, which was supposed not only to add and subtract, but also to multiply and divide - by repeated addition and
subtraction.
To solve the problem of transfer, Leibniz in 1672 invented the idea of „stepped reckoner” (so called Leibniz wheel).
It is unknown how many machines were manufactured by order of Leibniz. It is known however, that he was interested in this invention all his life.
One of Leibniz machines (preserved to this day) was made in 1694. The scientist devoted part of his personal fortune to the implementation of these projects.
Leibniz’s calculators
The mechanism of the machine can be divided to 2 parts.
The upper part is unmovable and was called by Leibniz Pars immobilis. The lower part is movable and is called Pars mobilis
Leibniz's solutions – first of all the Leibniz wheel were used in most of the later machines.
Leibniz's achievements important for computer science
• The Leibniz wheel (Stepped Reckoner)
• Four-action calculators
• The concept that the rules of thinking can be reduced to the rules of calculus on
symbols (formal logic)
• Diffusion of the idea of the binary system
Leibniz's successors
Giovanni Poleni (1683-1761) – Italian astronomer and inventor, built in 1709 a four-action machine powered by weights. The mechanism was based on wheels with a variable number of teeth.
Antonin Braun (1685-1728) – a German mechanic, presented in 1727 at the court of the Emperor of Germany a four-action machine, based on wheels with a variable number of teeth. Now this machine is in Vienna.
Jakob Leupold (1674-1727) – German machine builder, creator of the temporary toothed gear, another form of Leibniz’s wheel.
