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One
of the more visually spectacular types of slides prepared in
Victorian times were the preparations of crystallized chemical
compounds for viewing between crossed polarizing filters (Polariscope).
A large selection of these slides were produced by all the
commercial preparers and many amateurs, and they still amaze and entertain with their instant
transformation when viewing, from drab and colourless, into a kaleidoscope of
colour and form with the simple rotation of a polar filter. The addition
of a thin Selenite crystal or other wave modifying plate in the light path between the polarizing
filters, enhances the available colour variations. |
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Above,
a selection of crystallized chemical mounts by 3 of the most
successful Victorian age slide makers... (l to r)
early C.M. Topping, J.T. Norman, E. Wheeler, and
later C.M. Topping. All were made to be viewed between
crossed polar filters (Polariscope). |
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Crystallized
Aniline in polarized light with Selenite filter |
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Above,
a selection of crystalline mounts, obviously all by the same
maker (currently unidentified). All specimens are pharmaceutical
compounds, which possibly suggests the makers occupation.
Also note econdary retailers label from T.H. McAllister, New
York. |
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Various
Crystallized Chemical Compounds in polarized light with filters;
above, crystals of Sulphate of Strontium. Below,
3 variations of Salicine crystal mounts by J.T. Norman, with
one imaged below. |
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Above,
detail of crystalline compound Platino~cyanide
of Strontium imaged in Polarized light.
Below, a chemical mount of Potassium Chloride by
A.C. Cole with images taken from the slide with
crossed Polar filters (Polariscope). |
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