Grand Nachet microscope, C 1875
On application
A Grand Nachet microscope Signed on the foot: NACHET et FILS 17 rue St Severin, Paris’ . This is double pillar supported continental limb instrument. It comes with its original dovetailed case, lined in purple silk with padding. Several Nachet accessories are still present with the instrument. The optical tube slides into a carrier split in front to accept it. There is a calibrated draw tube. It has rack and pinion coarse and continental vertical screw fine focus. There are two original objectives, labelled ‘1’ and ‘2’ and a single eyepiece labelled ‘1. There are polarized light accessories; an over-the-eyepiece analyzer fits over any standard eyepiece, and would be used with the substage polarizer which fits into the substage ‘condenser fitting’. There is a solid inclination joint, allowing the instrument to tilt to any angle desired up to horizontal. The tension in this joint is adjustable by slotted screw. The unique mechanical stage combines left-right movement by knobbed screw on the left side of the microscope, with forward-backward movement in an arc controlled by a geared disc on the right side; this disc is knurled on on the outer side and is a gear on the inner half of its circumference. The stage clips point backward and are sprung, with push-button release of tension. The entire upper portion of the microscope can rotate around the stage. An understage ‘condenser holder’ swings out. A fitting slides in from below, and this fitting accepts accessories from above. These accessories include three different size pinholes, a diffuser screen and a polarizer. The distance from the slide can be adjusted by sliding the outer fitting in or out. There are two rods projecting down from the stage which, I assume would have supported an additional condenser. The octagonal mirror is plano-concave and easily adjusts in many directions, though it is not long enough to reach above the stage. There is a place in the case for a bench condenser for illuminating opaque objects from above. The condition of the microscope is good. Dimensions case 27 x 38 x 17 cm
