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.
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| 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 |
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| Dissecting microscope Nachet, Paris, about 1900 MM 82/018 |
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| 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 |
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| '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 |
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| 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 |
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| 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 |
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| 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 |
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Photographic Room, Medical School, University of Sydney, about 1900 |
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Catherine Smith |
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Medical Students, University of Sydney, about 1910 |
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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.
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| 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