MERCATOR, NICOLAS (the Latin name of NICOLAS KAUFFMANN), an eminent mathematician, was born at Holstein in Denmark in 1640. He visited England in 1660, when he was chosen a member of the Royal Society, and returned to Paris previous to his death in 1687. He was the first to detect the defect of Gerhard Mercator's projections, afterwards rectified by Edward Wright. Of all his works on cosmography and mathematics, by far the most original and valuable is his Logarithmotechnia, sive Methodus Construendi Logarithmos Nova; cui accedit Vera Quadratura Hyperbolæ, et Inventio Summæ Logarithmorum, London, 1668–1674, 4to.