Description

A very rare example of a prismatic very pocket microscope by cogit measuring 9,2×4,7×1,7cm.

The microscope is signed on one side : “Microscope de poche / à grossissement variable / breveté S.G.D.G. / Grossissement 50-75 fois” and on the other side : “E. Cogit & Cie / 36Bd St Michel / Paris”.

This triple prism pocket microscope was patented by the French firm Cogit the 12 July 1912 and illustrated in the newspaper “La nature” in 1914 (see the last picture).

The eyepiece and the objective lens are separate by only 4,5cm but three prismes give the possibilities of the very reduced size.

Cogit patented two models, one with only one power of 30 times and a more complexe (the present one) with power from 50 to 75 by sliding the inner part of the case.

The present microscope seems to be a very rare survivor of this very ingenious pocket microscope. The optics and prisms are still present but need to be cleaned by dismantling the entire microscope. Furthermore, the sliding stage is lacking. 

Anyway, a very rare and innovative little microscope, almost unknow from collector and litterature on microscopy.