The Microscope – Science by Design

This display shows a variety of microscopes from the Macleay Museum’s collection and emphasises some different types of design.

Simple and Compound

There are two basic types of light microscope - simple and compound. The simple microscope has one lens between the object and the eye. The compound microscoe has a lens, often made up of several elements, at thye object end (objective) and a lens, of several elements, at the eye end (eyepiece). Simple microscopes often have lower magnification than compound microscopes.

   
Simple microscope
E. Leitz, Wetzlar, Germany, about 1895
Compound microscope
E. Leitz, Wetzlar, Germany, 1894 (No. 29368)

These two microscopes have the same pattern foot and so serve to emphasise the difference in optical construction.

Simple microscopes

These have been made in a huge variety of forms, some just for examining specimens, others for dissecting them.

Van Leeuwenhoek microscope
A modern replica of the hand-held, simple microscopes Antoni van Leeuwenhoek (1632-1723) made and used in his microscopical investigations.
MM 82/015

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Simple microscope
Nachet, Paris, about 1900
MM 82/017

eSbD-NachetH21.jpg (4315 bytes)

Dissecting microscope
Nachet, Paris, about 1900
MM 82/018

eSbD-NachetH22.jpg (2809 bytes)

Dissecting microscope
Watson & Sons, London, about 1890 (No. 2306)
MM 82/016
 

Compound monocular microscopes

These four microscopes illustrate different designs for controlling coarse focus.

Unsigned, possibly made by King of Bristol about 1840.
The coarse focus is adjusted by the rack and pinion on the limb at the back.
MM 82/061

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R.W. Wright, London, No. 106, made about 1880. The helical groove in the optical tube allows it to be raised or lowered for coarse focus.
MM 91/040
 
'Universal Microscope', R. & J. Beck, London, No. 4808, made about 1867.
The optical tube is raised and lowered by a chain drive.
MM 82/024

eSbD-BeckH15.jpg (3898 bytes)

Baker, London, made about 1860.
Coarse focus is by rack and pinion directly on the optical tube.
MM 91/001

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Microscopes at the University

The concluding part of the display shows microscopes used in teaching and research in the University of Sydney

'Museum microscope'
Watson, London, made about 1940.
This microscope enabled a sequence of students to examine five slides in turn without handling the slides. A larger model could accommodate twelve slides.
MM 77/037

eSbD-WatsonH38.jpg (2667 bytes)

Wenham binocular microscope
Swift & Son, London, made about 1900.
A prism deflects light up the diagonal tube giving a form of stereoscopic image. This microscope was used by T.W. Edgeworth David, professor of geology, 1891-1924.
MM 82/027

eSbD-SwiftH31.jpg (3776 bytes)

Compound microscope
Ernst Leitz, Wetzlar, Germany, No. 266266, made in 1928.
The microscope stand (Type G) was supplied with alternative monocular and binocular bodies. Isobel Bennett used this microscope in working with William Dakin, professor of zoology, 1928-1948, for the preparations discussed in Dakin's publications between 1932 and 1950, including his monograph on the plankton.
MM 82/025

eSbD-LeitzH18.jpg (4400 bytes)

dOld Med2.jpg (27772 bytes)

Photographic Room, Medical School, University of Sydney, about 1900
Apart from the magnificent bellows camera, the photograph also shows a microscope fitted with a camera lucida, a Darwin rocking microtome, a sledge microtome and a freezing microtome.
Rare Books, Fisher Library

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Catherine Smith
Demonstrator in the Geology Department,
University of Sydney, about 1915
University of Sydney Archives

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Medical Students, University of Sydney, about 1910
Rare Books, Fisher Library


Electron Microscopy

The resolution of an image - the amount of detail that can be seen, not just magnification - in a light microscope is governed by the wavelength of light. Electron microscopes can resolve much finer detail because the wavelength of electrons is much smaller.

Electron microscopes were first developed in the 1930s, and are now used throughout the world. There are two main types, the scanning electron microscope (SEM) and the transmission electron microscope (TEM).

Scanning electron microscope specimens
Specimens to be examined with a scanning electron microscope must first be coated with a very thin layer of gold or platinum. The specimens will then conduct electricity rather than building up an electrostatic charge that would deflect the electron beam. Electron micrographs of two of the specimens are shown.

   
 Egg cases, Citrus Bug
EM Unit
 Head of a Bull Ant
EM Unit

"But some may possibly enquire, to what Purpose Providence has bestowed such an Expence of Beauty on Creatures so insignificant: and then cry out, What is all this to us?—- My Reply is, that the Beauty and Elegance which adorn them, are evident and convincing Proofs of their not being so insignificant as we presumptuously suppose they are: for, such beauty must be given them, either for their own Sake, that they themselves may be delighted with it; or else, for Ours, that we may observe, in them, the amazing Power and Goodness of the Creator. If the former be the Case, we must allow them to be of Consequence in the Account of their Maker, and therefore deserving of our Regard; and if the latter, it is really our Duty to take notice of and admire them."

Henry Baker, The Microscope Made Easy, 1744