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Compound non-achromatic microscope

Maker

UNKNOWN

Country

France

Signature

Unsigned

Category

Microscopes

Optical 1

Compound

Optical 2

Non-achromatic

Size of the box (h x b x d)

9.2 × 26.5 × 14.3 cm

Size of the microscope (h x b x d)

24 × 11.5 × 8 cm

Inventory number

SM 21

Description

The microscope is stored in its original wooden box.
It consists of a lead weighted brass footplate on which two round pillars are mounted. The mirror is mounted in a bracket on this foot. The simple stage is mounted in sleeves between the two pillars, in one of which the fine adjustment with rack and pinion, which acts on the stage. On top of the two pillars is a connecting limb with a sleeve in which the body tube can be adjusted. On this sleeve is mounted an adjustable bull’s eye for incident light.
There is a Huygenian eyepiece with a focal length of 40.4 mm, its magnification is 6.2×.
There are three biconvex objective lenses in a mount, numbered 1, 2 and 3. Lens number 1 is light green, which is caused by contamination of the glass with a trace of iron. The other two lenses are white. The lenses were investigated on the microscope itself.

Objective 1 2 3
Focal length (mm) 20.4 13.2 8.9
Magnification 39.4 61 96.4
Numerical aperture 0.033 0.051 0.085
Resolving power (µm) 10.5 6.25 4.25
Star test good good good