Hooke's compound microscope and its illuminating system, 1665-1675.
© Science Museum / Science & Society Picture Library
Full-size reconstruction of Robert Hooke's (1635-1703) compound microscope copied from the engraving and description in his book 'Micrographia' (1665), the first important work on microscopy. The microscope was focused by moving and turning the microscope on a screw thread, rather than moving the specimen, which was mounted on a spike. The eyepiece lens was at the top of the microscope and an objective lens next to the specimen. Hooke inserted a field lens between these in order to increase the field of view. He used his pioneering compound microscope, with its two lens systems, to examine a flea, a piece of cork and many other specimens. The illumination system used a liquid-filled globe to project the flame of an oil lamp onto the specimen.