A drawing of one of Antoni van Leewenhoek's single-lens microscopes. The drawing was done by John Mayall, Secretary to the Royal Society, from a specimen housed in the museum of Utrecht University. It was published in The Microscope & its Revelation, 7th edition, by W.B. Carpenter (1891). Leewenhoek reputedly made 500 microscopes during his life (1632-1723), 26 of which were sent to the Royal Society on his death. These 26 have since disappeared. The drawing shows the design of a typical Leeuwenhoek microscope, back & front, the single lens in a pair of metal plates, with the specimen pin attached to a device for adjusting its height. Reference: MICROCOSMOS, page 186.