Scientific Instruments - Mechanical Calculators

The first mechanical adding machine was made by the French mathematician Blaise Pascal in 1645. This had a number of interconnected wheels, each with ten teeth representing the digits. Numbers were added by advancing the appropriate wheels. The German philosopher Gottfried Wilhelm von Leibniz extended to Pascal’s machine to doing multiplication by repeated addition.

The mechanical principles of these adding machines were used in hand cranked calculators during the 18th and 19th centuries and electrically powered calculators up to the 1950s.

The first calculating machine to be produced in large numbers was made in France by Thomas de Colmar in 1820. The machine, called an "Aritherometer" and its clones was made up until the 1920s.

 Colmar's Aritherometer

In 1905, the Swedish inventor Willgodt Odhner made an adding machine based on a pinwheel mechanism. Dozens of companies made machines incorporating this mechanism which soon superseded the Colmar design. The market leaders were Swedish company Facit, founded in 1918, and the American company Monroe, founded in 1911. Both closed in 1960.

1930 Monroe Adding Machine 1950 Facit Adding Machine


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Scientific Instruments - Microscopes

In about 1610, the Dutch lensmaker, Hans Jannisen, and his son Zacharias made an instrument consisting of a pair of lenses mounted in a sliding tube, which is regarded as the first microscope. The addition of a condenser lens to concentrate light on the specimen, a specimen stage and controls for moving the tube came quickly.

Britain became the major centre for the manufacture of microscopes but there was little further change in the design of microscopes until the late 18th century when compound lens were introduced to correct aberration. At about the same time, English manufacturers introduced a ball-joint at the base of the microscope which allowed it to be tilted for more convenient viewing.

In the early 19th century, the portable microscope, whose parts came in a small box and were fitted together for use, was introduced.

 Kellner microscope (about 1850)

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Scientific Instruments - Telescopes

The telescope was invented in Holland in about 1608. It is usually ascribed to Hans Lippershey, a spectacle maker, who applied for a patent based on the observation that placing a concave and a convex lens in a tube magnified distant objects With at least two other Dutch inventors of similar devices at about the same time, the States General ruled that the device was too easily copied to be patentable. The first recorded demonstration of a telescope was by Galileo in 1609. Newton's telescope

Johannes Kepler discovered the principle of the astronomical telescope, which uses a different combination of lenses to give a brighter but inverted image, and his design was constructed by Christoph Scheimer, a German Jesuit astronomer, in 1630. Because of problems of spherical aberration, astronomical telescopes had to be very long - sometimes more than 60 metres.

To overcome the problem of lens aberration, attention turned to the possibility of using mirrors rather than lenses in telescopes. Isaac Newton constructed the first reflecting telescope in 1668 but viewing with it was difficult because the eyepiece and the head of the viewer blocked a lot of the incoming light. William Herschel solved the problem by tilting the mirror in his telescope (which was about 12 metres long).

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