Description

EARLY DUTCH MATHEMATICAL RULE, second half 18th century, signed “I. Reghter, Delft.” This thick brass rule, 14-3/4″ (37.5 cm) long, is divided on both sides with a total of six strongly nonlinear scales plus one scale of (Delft?) inches running from 0 to 12, the inches divided respectively into halves, thirds, fourths,…, twelfths (each inch 26.3 mm long). Scales are labeled cryptically “S,N” (1-32, 1-100), “V,R” (1-32, 1-125), and “L,T” (1-32, 1-125). Condition is fine except for several stains to the rule. We do find Reghter’s trail in the references — Zinner lists him as “I. Rechter a Delft,” known for a planetarium (in the “Leiden Museum”, #A182). King and Millburn describe this as a double-cone planetarium, and refer to Jan or Johannes Reghter (1730 – 1801) of Delft, “a highly skilled maker of compound microscopes, geometrical instruments, and electrical apparatus.” Reghter was a published scientist in his own right. He designed and built an atmospheric electrometer which won a prize contest in 1786, and which led to a quarrel when van Breda, who had commissioned Reghter to develop this instrument, took all the credit and the prize (see Zuidervaart, 2006). We have had one other instrument by this maker, an unusual mechanical level with integral scale rule also with the undecoded “V,S,L” scales (Tesseract Catalogue 76, Item 34).