Accession No

1805


Brief Description

achromatic compound microscope, by Tulley and Sons, English, 1835 (c)


Origin

England; London; Islington


Maker

Tulley and Sons


Class

microscopes


Earliest Date

Jan. 1, 1835


Latest Date

Dec. 31, 1835


Inscription Date


Material

metal (brass, oxidised brass, steel); glass; wood, ivory


Dimensions

overall height in vertical position 462mm; minimum height 375mm; breadth 245mm; depth at minimum height 400mm; depth at maximum height 267mm


Special Collection

Heywood collection


Provenance

Purchased from the H.Heywood collection under estate duty exemption benefit with the assistance of a Science Museum PRISM grant-in-aid.


Inscription

‘Tulley & Sons, Islington, London’ (body)
‘141’ (one eyepiece)
‘203’ (triangular nippers)
‘169’ (objective (?contemporary))
‘478’ (second objective)


Description Notes

Brass. Flat tripod foot. Pillar to compass joint; bar to square stage, with knurled screws operating mechanical lateral and longitudinal movement. Fittings for stage forceps and triangular nippers; tail piece with mount for rotating diaphragm and small screw-fit condenser; swinging plano-concave mirror. Limb at 45˚ angle to stage. Body with racked draw tube and supported by two telescope-type steadying arms from ends of feet to lug on body (locking nuts on arms). Two draw tubes graduated 1 - 12 inches with clamping rings around each draw tube. 5 screw-fit eyepieces. Telescope-type erector. Substage ring with detachable ring diaphragms and single lens condenser. 2 objectives, one fitted with a lieberkuhn. Substage ring with tilting stage. Three pairs of stage forceps. Standard condenser lens. Two dust covers. Detachable stage plate. Triangular nippers. Two pairs of slide clips. Top stage. Plain ring to fit substage.
Fitted wooden box.


References

Boris Jardine; 'The problems with lenses; and the 19th-century solution'; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge; 2008: https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/microscopes/problems-lenses-and-19th-century-solution


Events

Description
This is an example of J.J. Lister’s design for the achromatic microscope, made by Tulley in the early 1830s. By combining lenses of different materials, the problem of chromatic aberration could be virtually eliminated, vastly improving the performance of the microscope.

Chromatic aberration was a big drawback when using early versions of the compound microscope. It is caused because when light travels through an ordinary lens each colour is bent through a different angle. A spectrum of colours will appear around the image being viewed.

Chromatic aberration was overcome due to the important work by Lister in 1830 who developed the achromatic lens for microscopes. The new type of lens prevented colour separation by combining two lenses made of different types of glass. The first lens that light passed through would split the colours and the second lens acted to bring the colours back together again. This produced a much sharper and clearer image than was previously achieved.

In the Victorian period the achromatic microscope became a vital tool in medical and scientific research. Improvements to the optical performance of the microscope saw developments in the design and construction of the microscope. The microscope became sturdier and could focus to a finer level.

Scientific instrument makers in the Victorian period who improved the rigidity of the optical tube and the focusing ability of the achromatic microscope include Andrew Ross, James Smith and Hugh Powell.

22/08/2006
Created by: updated by Ruth Horry on 22/08/2006


FM:40059

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