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Compound achromatic student microscope

Year/Period

1880-1910

Maker

SALMAN

Country

United Kingdom

Signature

J. Salman & Son Makers / 4 Seymour St. Euston Sq re / London N.W.

Category

Microscopes

Optical 1

Compound

Optical 2

Achromatic

Size of the box (h x w x d)

39 × 22 × 20.1 cm

Size of the microscope (h x w x d)

34 × 11.8 × 17 cm

Inventory number

SM 26

Description

The microscope is kept in a wooden box with three drawers.
It is a simple student microscope with an ‘English foot’, mounted on a wooden board which slides into the box. The upper part of the microscope is mounted between trunnions. Coarse adjustment is by rack and pinion, fine adjustment by means of a lever acting on the nose piece. The circular stage has a simple mechanical attachment. Below the stage a rotating stop with four holes. There is a concave mirror in a bracket.
Accessories are a bull’s eye condenser on a stand for incident light and a live box.
The Huygenian eypiece has a focal length of 36.2 mm, its magnification is 6.9×.
The objective lens has a RMS thread, it is marked ‘weak’ and ‘strong’. There are three combinations possible. It was measured on its own microscope.

Objective 1 1+2 1+2+3
Focal length (mm) 18.55 9.54 7.23
Magnification 45.92 93.48 129.5
Numerical aperture 0.088 0.18 0.25
Resolving power (µm) 4 2.5 1.75
Star test coma coma coma