Rare example of the sophisticated compound microscope made by George Adams Senior, which he described as a variable microscope. The instrument is mounted on a toothed wheel, which enables its inclination to be varied on a pillar resting on a tripod. On the wheel is fastened a rod carrying the mirror, the stage, and the body-tube. Focusing is by turning a threaded rod. The microscope has an eyepiece with two lenses, a field lens, and an additional lens, all converging. Below the eyepiece is inserted a micrometer moved by rackwork, followed by a screw for micrometric adjustment. The instrument can be taken apart and put back in the wooden box, which contains many accessories including three series of objectives, a brass compressor with glass disks, and various objects for holding specimens. Also present is a lamp fitted with a converging lens to concentrate light on the specimens. Provenance: Lorraine collections.