Essay de Dioptrique

full text facsimile available to download from Google Books.

First published in French. It was published in Dutch translation by A. Blok as Proeve der Deurzicht-kunde in 1699. Leeuwenhoek had a copy in December 1698 when he wrote to Harmen van Zoelen about Hartsoeker's claim to have been the first to discover sperm. The Dutch translation had a cover illustration by Jan Luykens.