Description

UNCOMMON ALL-BRASS SLIDE RULE, French, mid-19th century, unsigned but probably by Richer, stamped on the case “Règle Logarithmique.” Measuring a full 17″ (43 cm) overall, this substantial rule is made of solid brass, apparently, with a heavy non-tarnishing gray finish. It has a reversible slider, all precision divided with logarithmic “Nomb.” scale, and with transcendental trigonometric functions “Sinus,” “Tang,” and “Caract” scales. Condition is very fine, complete with the original leather covered wood case, the ends notched for use of the calculating rule in place.