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Special Exhibition Label: 'Geek is Good' (15 May - 2 November 2014)

Testing the Limits

How far could a microscope see? What level of detail could it resolve?

No one pushed the passion for exactitude further in the 19th century than Friedrich Nobert. The two small and inconspicuous items presented here are examples of his test plates. These consist of bands of lines precisely ruled on glass by a diamond. The spacing of the lines was made progressively finer to provide a challenge to microscopists: the better the quality of the microscope, the finer the set of lines that it could resolve.

J.J. Woodward successfully resolved Nobert’s 19 band plate in 1869 and produced a series of photographs of each of the bands (one is shown on the left). Nobert then produced a 20 band plate which proved to be beyond the powers of a light microscope. It was only resolved by an electron microscope in the 1960s.

Beyond these ultimate tests, most microscopists revelled in the sheer diversity of nature. The manuscript on the right is an illustrated classification of the tiny creatures known as rotifers, written by Thomas Bolton in 1889. The scale of the achievement and the pleasure in the detail is clear when it is realised that most rotifers are 0.1–0.5 mm long.

MHS inv. 14571 (Nobert 19-Band)
MHS inv. 43841 (Nobert 20-Band)
MS RMS 17 (Bolton)

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