Leeuwenhoek microscope, c 1670.
© Science Museum / Science & Society Picture Library
Replica. This microscope was made by Antoni van Leeuwenhoek (1632-1723), a Dutch microscopist who was the first to observe bacteria and protozoa using his own simple microscopes. This one consists of a single double convex lens mounted between two thin bras plates riveted together. The object to be examined is held in front of a lens on the point of a short rod which is mounted on a small bras block loosely riveted to coarse-threaded screw; this acts through a socket angle-piece attached to the lower end of the plates by a thumb-screw. In this way the object can be brought in front of the lens, and focusing is effected by a thumb-screw pasing through the mounting block and acting against the plates.