Abstract

Summary The contribution of the Antwerp mathematician and instrument maker Michiel Coignet to the development of the sector is investigated. It will be shown that he invented a rule, the reigle platte, which he later used in conjunction with Mordente's reduction compass, thus in effect performing the same operations as with a sector. Later Coignet transferred the scales to the legs of the compass thereby making his first sector, which bore a resemblance to the reduction compass.