Compound drum-type microscope by Treycourt & Oberhauser, 2/4 19th C.
Signed: Treicourt & Georges Oberhauser. Place Dauphine N.° 19 a Paris. Brevet d'Invention
Base diameter 9,2 cm
Case 29 x 16 x 20 cm
This all-brass instrument has a circular base supporting a cylinder that houses the rectangular mirror. The stage can be rotated and has two clips. A pillar sustains the arm that carries the body tube. Coarse focus is by moving the tube within its sleeve; under the pillar there is a knob controlling the fine focus by a direct-acting screw.
The optical system comprises two objectives signed 4 and 7, with six additional lenses contained in a pasteboard box; two eyepieces signed 1, 2 and 3; three brass stops.
The pinewood case has the supports covered with green baize and brown velvet lined inside the lid. There is a box (25,8 x 3,6 x 9 cm) that contains the accessories, housed under the eyepieces.