AN ISLAMIC ENGRAVED BRASS ASTROLABIC QUADRANTMOROCCO, ENGRAV...

Estimate

£3,000 - £5,000

AN ISLAMIC ENGRAVED BRASS ASTROLABIC QUADRANTMOROCCO, ENGRAVED WITH DATE 1256 AH/1840-41 ADThe six-inch radius dial plate engraved with sexagesimal trigonometric grid within twelve annotated panels corresponding to five grid divisions to the radius margins, over eighteen conforming panels to the curved margin, the obverse engraved with Andalusian Kufic inscriptions and projections for Marrakech, one edge fitted with a pair of pin-hole sights and the apex drilled for plumb line and bob beneath a suspension loop and shackle.The plate 15cm (6ins) high, 20.5cm (8.125ins) wide.Quadrants incorporating trigonometric grids were the most popular astronomical instrument used in the central regions of the Islamic world (Egypt, Syria and Turkey) from the 15th century onwards. The grid comprises orthogonal lines for calculations with trigonometric functions to the base of 60. This was first devised in the 9/10th centuries and became standard in the Middle Ages.The present lot represents the flourishing tradition of the scientific arts in the Maghrib where makers of instruments tended to follow the tradition of their masters (see Madison, Francis and Savage-Smith, Emilie Science, Tools and Magic: Part One page 260). This quadrant can be compared to an early 19th century example in the Museum of the History of Science, Oxford (Acc. No. 1956-127) as well as a later 20th century example in the Khalili collection (Acc. No. SC141 - see Madison and Savage Smith page 265 no. 155).