Modified Marshall type compound microscope, 1720.

Following the publication of Robert Hooke's 'Micrographia' in 1665, English makers, notably John Marshall (1663-1725) began to produce large compound microscopes based on Hooke's design. Although this instrument resembles those made by Marshall in general form, it differs from them in several important respects. The pillar is fixed vertical, with the ball-and-socket joint of earlier instruments having been dispensed with. The microscope is also fitted with a plane illuminating mirror which does not appear to have been fitted to any of Marshall's instruments. Optically the instrument is very much of the Marshall form, there being a single-lens objective, a large field lens and an eye-lens.