"GRAND BINOCULAR" - MONOCULAR MICROSCOPE 1881-1886
French: signed NACHET ET FILS, 17, rue St. Severin, Paris
Nachet's Grand Model Stereo-pseudoscopic - Monocular Microscope Compendium as described in Carpenter's The Microscope. This outfit is accompanied by an elaborate array of 40 accessories as described on pages 4 and 5 of Nachet's 1881 catalogue. In this type of binocular arrangement the interocular distance is adjusted by turning a screw furnished with two threads of different speeds, thus an inclination is given to the prism equal to half the angular displacement of the tube. An unusual mechanical stage is present which employs the usual screw driven horizontal movement and a geared thumb-wheel which pivots the stage about an axis to the left the stag&s central aperature thus providing vertical movement in an arc. The top of the stage has a slide rest and two spring loaded slide clips which pivot vertically and horizontally. The entire substage apparatus is raised and lowered along a dovetailed rail by means of a lever. A plane and concave mirror is held in a gimbal attached to the tailpiece by means of an articulated arm.
The outfit appears to be all original, functional and complete but for a couple of minor accessories and a freestanding bull's-eye condenser. The compendium packs into its original fitted, dovetailed , brass-bound mahogany case with working key. Individual leather covered, fitted cases are provided for the binocular head and for the nine objectives. Three fitted stacking trays hold the remaining accessories. Condition of the stand is very fine, the brass retaining nearly all of its original clear lacquer finish noting minor scratches. The condition of the accessories and optics is excellent. Overall, a stunning example of French design, fit and finish in Nachet's Binocular - Monocular "Grand Model" Compendium with its impressive array of 40 accessories.
The identical instrument is described in Maison Nachet & Fils Catalogue Descriptif Des Instruments De Microgaphie, Juin 1881, pp.8-9.