Compound microscope

The upper part of the tube is cylindrical with consistent dimensions, forming a cone at the bottom. The eyepiece is at the top in a cylinder that moves under friction. At the bottom, on a pillar arm, are the lenses that also hold the tube in place. The arm holding the tube is on a pillar that moves vertically, using a rack mechanism that is controlled with a side screw to enable coarse focusing. The tube moves with the inside of the pillar. The outside is fixed in place and supports the stage and mirror. The stage is therefore also static, and has a large hole to let through light reflected from a mirror that is located lower down the fixed pillar. The pillar, in turn, is attached to a pedestal, which rests on a round metal base. The base bears an inscription identifying the manufacturer as "Bate. London."

Robert Brettell Bate was an English maker of mathematical, nautical, and other scientific instruments in the early 19th century. His workshop was at No. 21 Poultry in London, as is stated on many of his labels.