Compound achromatic microscope

Description

In mahogany box, lined with red and purple silk and velvet.

This is Nachet’s ‘Grand Modèle’, the large stand. The microscope rests on a heavy V-shaped foot plate on which two pillars are mounted. The foot plate is made of lead-weighted brass. The optical part of the instrument is mounted between trunnions, the upper part of the optical system (the stage with the limb and the body tube) can be revolved around the optical axis (platine à tourbillon), which is fairly common in French microscopes of the period. Under the stage the flat and concave mirror in a bracket, mounted on a shackled chain in order to be able to move it in or out of the optical axis. There is an attached mechanical stage with movements in the X and Y axis. Coarse focussing is by means of rack and pinion, fine adjustment is by means of a micrometer screw acting on the limb.

It is a mineralogical microscope, unfortunately, the polarizer and the eyepiece with the analyzer are missing. The objective is of the ‘node’ type, customary for Nachet, it consists of three achromatic doublets.

In the box an empty sleeve for an objective ‘Nachet / 9 / Imm. huile’ (= oil immersion objective lens) and a so-called tourmaline.