Nicolaas Hartsoeker

Nicolaas Hartsoeker was a Dutch mathematician and physicist who invented the screw-barrel simple microscope around 1694, born on 26 March 1656 and dying on 10 December 1725. The son of a Remonstrant minister, he grew up in Alkmaar and Rotterdam and made his living as a lens maker, instructed in optics by Antonie van Leeuwenhoek. In 1674 he and a fellow student, assisted by Leeuwenhoek, were the first to observe semen, which led to a priority dispute with Leeuwenhoek. In 1677 he met Christiaan Huygens and initiated him in lens making, and in 1678 accompanied him to Paris as assistant, where they impressed with their microscopes, though a fall-out followed when Huygens failed to mention him in a French publication. His instrument-making and wine business failed, and in 1684 he moved to Paris, where he made instruments for the observatory and the academy.