French Double-Pillar Microscope (No. 32 )

Age: c1870
Made by: Possibly Edmund Hartnack
Made in: Probably France

This is a compound microscope constructed of brass with a cast iron base painted green, with two pillars ("trunions") supporting the stage and body pillar. The microscope optics consist of a single-lens objective screwed into a tapered nosepiece, and a Huygenian eyepiece. There is only one objective remaining with this instrument. It is marked "|||". The eyepiece is unmarked, and consists of two plano-convex lenses (Huygenian type). There are no other optics in the body. The total height of the instrument is 45cm.

Focus is via a rack & pinion mechanism with the rack machined into the body tube. The thin pinion shaft has two thumbscrews so focusing can be done either left- or right-handed. it is screwed to the body support tube and is itself screwed to a cantilevered limb. Mechanically, the limb is attached to the top of the round support pillar. Also attached to the limb is the ball-mount for the two-section articulated arm that supports the bull's eye lens. The sample stage is circular with two holes: one for the support pillar and the other, located axially, for sample illumination.

The stage is supported on either side by two large pillars which are fastened to the oval, cast iron base. There are two thumbscrews on either side that can be loosened to allow the microscope to be tilted, and tightened to fix it in place. The illuminating mirror is mounted to the base of the support pillar. Imaging is fair using the one included objective, but exhibits both chromatic and spherical aberration.

This microscope is very similar in design to this instrument signed by E. Hartnack. In addition, there are other, French double-pillar microscopes signed by "Radiguet et Fils, Optns 15 Bd des Filles du Calvarie, Paris"; "Maison de L'ingr Chevallier, OPTN, Pont Neuf 15, Paris."; "Radiguet et Massiot, Optns 15 Bd des Filles du Calvarie, Paris"; "J. Bianchetti, Marseilles" even Nachet (see this site). Thanks to Ms. Cassidy Schichnes for photographic assistance.

Microscope featured 07/2016

Thu, Jun 30, 2016