EIGHTEENTH CENTURY DRAFTING INSTRUMENT FROM THE RHONE-ALPS, BY AN UNRECORDED MAKER, French, signed “Chavant à Nantua, 1783.” The 4-7/8″ x 6-1/2″ (12 x 16.5 cm) brass square has an alignment bar along the short outer edge, and twin shaped ends. One side is divided with a scale of old French measures, a “Demi Pied de Roy,” the sixth “inch” subdivided into twelfths (i.e., Lignes). The reverse has a scale of equal parts, labeled “Echelle de Toise” and with transversal interpolation. Condition is good noting a hairline crack and some old denting.
We find no record of the instrument maker Chavant. Nantua is a village about 50 km west of Geneva, with a population of approximately 3000, a size unchanged for at least 250 years.
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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 firstname.lastname@example.org.