Stock Number: 10493


For sale, antique mathematical sector. This is a substantial instrument, with beautiful floral engraving at the hinge. There are three different doubled scales on each side including one with planetary symbols of metals.


17-1/4 inches (44 cm) open


c. late 17th century

Country of manufacture


Categories: Scientific, Calculating


EXCEPTIONAL MATHEMATICAL SECTOR, European, probably German, c. late 17th century. Opening to 17-1/4″ (44 cm) this substantial brass sector is constructed with an unusual “sandwich” hinge of concentric disks. The inner disk is hand engraved with a wonderful “rosace” on both sides. The head of each arm is engraved with sinuous floral designs, different on the two sides. There are three different doubled sector scales on each side, including one pair with the planetary symbols of metals. Condition is generally fine noting some nicks and scratches.

The decoration on this sector is some of the most appealing we have seen, but identifying the country of origin is difficult. We see considerable similarities to early German sectors, yet the floral images are similar to those on a Blondeau French pearl sizer, and on those on an early Edmund Culpeper English set we had (Tesseract Catalogue G Item 55). A pleasing mystery. 

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David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at [email protected].

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