Leeuwenhoek Replica Microscope, by John Mayall, London, 1886

This replica of a late 17th century van Leeuwenhoek simple microscope was made in 1886. Two brass plates riveted together hold a small lens with an aperture of 0.5 mm. Specimens are held on a pointed carrier mounted on a screw for positioning. A short perpendicular screw adjusts the focus.