probably made in Edinburgh
These three polarising accessories are parts of a microscope made between 1823 and 1829 by Alexander Adie (1775-1858), a scientific instrument maker based in Edinburgh. The instrument is the earliest known polarising microscope.
The black glass analyser (left) fits on top of the eyepiece. The tourmaline analyser (right) can be rotated to find the greatest angle at which light diverges. Both are used with the parallel glass plates (centre), which work as a polariser.
By the time the instrument was delivered to the Royal Society in 1829, the cumbersome polarising apparatus had been rendered obsolete by the convenient Nicol prism, invented by the Edinburgh geologist William Nicol (1768-1851).
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