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fine Microscope Achromatic by Vincent Chevalier. Signed on the tube: Microscope Achromatic – Vincent Chevalier – Ing Brevete – Quai de l’horloge 69 – Paris. In original case with several accessoires. The measurements of the box are 15 x 21 x 9 cm and I will date the microscope 1820-1830.
It is one of the first microscopes having as objective a system of lenses able to correct satisfactorily the chromatic aberration. The tube is vertical and is supported by a ring connected by means of a short arm to a vertical bar. The stage consists of a square plate with a hole in the center. A rotating horizontal disk having five holes of differents diameter allows to restrict adequately the observation field by transmitted light of the original concave mirror. The observation are possible also by incidence using light coming from a convergent lens (bulls eye) placed at the end of a thin adjustable arm fixed to the stage. The eypiece is held by a short tube which can be pulled out of the body of the microscope. The whole optical device can be extracted from its supporting ring. The instrument is equipped with two exchangeable eyepieces and two objective. The vertical bar is screwed in a wooden case where the instrument may be kept.