| Toward the end of the 19th century apparatus manufacturers sold
sets of polarization samples to be viewed between crossed polarizers in
Pickering-type polarimeters
. Typical of these was the boxed set of a dozen 3 inch square samples selling
for $20.00 "in neat wooden box" sold by James W. Queen & Co. of Philadelphia
in 1887. Curiously enough, all three examples I have examined and show here
show the same splitting-out in the upper front corners.
These sets included, among others, specimens of salicen and benzoic acid crystals, a wedge film, designs made in varying thickness of mica, and a quarter wave plate. The large trays of individual samples at the bottom of
the page are at the United States Military Academy, and have recently been
reorganized by Col. Bruce Oldaker. Similar specimens from Queen cost in
the $1.50 to $6.00 range, which made the possession of a large set quite
expensive.
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