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English Silver Scale Rules and Protractor. Signed: E. Nairne London, third quarter 18th century.
Made of Silver. Both sides engraved with English drawing scales, diagonal scales, proportional scales for logarithmic calculations involving chords, sines, secants, tangents, etc. The upper side has also a rectangular protractor for measuring angles. This type of scale rules are typical for the 18th century and often part of a case of drawing instruments.
For similar examples see Drawing Instruments by Maya Hambly, figure 110 on page 117 and the plates XI, XII, XIII and XIV.
Edward Nairne had a workshop in London from 1748 till 1796 and from 1774 till 1793 in collaboration with Thomas Blunt (instruments signed: Nairne & Blunt).
Dimensions 15,2 x 5 cm (6 x 2 inch).