This monocular microscope from E. Messter is a late 19th century apparatus. Medium size 30 cm. high, made of brass optical components and the stand and plate of blued black iron. It has a coarse focus by means of a rack engraved on the optical tube and a fine focus by a vertical spring located on the support shaft and operated by a horizontal knurled wheel.
The optical tube ends in two objectives that are screwed into a circular brass stage, which are exchanged by turning it. The objectives are made up of overlapping circular lenses that can be screwed together. It is an original system, precedent of the revolver. I don’t know of another manufacturer that has used this solution for lens swapping.
The condenser is a five-diaphragm wheel and is located under the stage. This is square and wide 10 x 8 cm. The foot, in black-blued iron, is horseshoe with a rear extension measuring 13 x 9 cm. On the optical tube there is a metal label with the manufacturer’s name: Ed. Messter. Berlin
It has a 35x15x13 cm beech wood case. It has a note inside with its manufacturing number: 34,797 and the magnification table. The address of the workshop at this time was, Leipziger Strasse, 118.Berlin W.66.