A parallelepipedic bar, which holds the microscope body, the stage and the condenser, is connected by means of a joint to a vertical support resting on a steady tripod. The joint allows the optical axis of the microscope to assume any orientation. The movement of the stage along the bar is controlled by a rackwork. The condenser consists of a concave mirror and a convergent lens connected to slides gliding along the bar. The light reflected by the mirror is focused by the lens onto the specimen. A second convergent lens is supported by a thin arm fixed to the stage and allows observations by incident light to be carried out. The instrument, entirely of brass, may be kept in a wooden case. It is equipped with three objectives of different focal lenght and with a number of sample-holders and other accessories. Well-preserved. Overall height 45 cm, with the bar in vertical position. Signed: "Dollond. London". Mid-19th century.
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