Description

AN EARLY 17th SECTOR WITH RADIAL LINES

Brass, 18 cm (7 1/8”) x 3,5 cm closed, 1/8” thick

One side is radially divided with linear scales running from 0 to 90, in units, starting at the hinge and terminating at the tips. The other side carries another linear scale running from 0 to 100 at the ends.

The sector can be used to divide lines and circumferences into equal parts and for drawing regular polygons. Besides, it can be used to trace distances between two points or for artillery use.

Condition is good with an original patina, noting some scratches in the rounded hinge.

Decorative shaping is suggestive of an early 17th century origin.

Origin: Continental Europe, possibly Germany.

Provenience: private European coll.

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Christophorus Clavius in his “Geometria practica” (1608) developed the scales making them radial and giving a more practical use to it.

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