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Mechanical division
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One of the first machines for performing semi-automated divisions of graduated scales of scientific instruments was developed in the 1760s by the Duc de Chaulnes. He used a circular platform, which held the circle to be divided. The platform was moved by means of a tangent endless screw. The divisions were inspected with micrometer microscopes. When the screw was rotated, the platform turned by the desired increment, and a mechanical system marked the divisions.

The method used by the Duc de Chaulnes was perfected by Jesse Ramsden, who, in the 1770s, built a more accurate dividing machine. Ramsden manufactured high-quality parts that made his machine exceptionally precise. Even an unskilled worker could accurately divide the limb of an octant or sextant in a relatively short time. Other machines, also incorporating micrometer screws, were used to divide linear measures and mark equidistant divisions on thermometers.

In the nineteenth century, other great instrument-makers such as Troughton, Gambey, Lerebours, Repsold, Porro, and Amici added many improvements to dividing machines.

Objects
Circle-dividing engine

Circle-dividing engine

Inv. 586, 3244
Maker unknown, Florence, 1762

Dividing engine

Dividing engine

Inv. 3457
Maker unknown, Florence, first half 19th cent.

Line-dividing engine

Line-dividing engine

Inv. 1023, 3244, 3368
Maker unknown, Florence, second half 18th cent.