Usage/History: Used for examining crystals, quartz,
mica, optical glass etc. in polarized light. With the use of
the accessory tube and holder it can also be used as a polarimeter
(though a rather inaccurate one) for measuring the polarization
of optically active liquids. In this instrument the light is
polarized using a tiltable glass plate (missing) above the mirror.
The light may either be reflected directly to the specimen, or
down to the mirror and then passed back through the plate to
the specimen, and then to the nicol prism analyzer. Alternatively
a black glass or pile of plates analyzer may be used. Both the
specimen stage and analyzer are mounter in graduated circles
to read the degree of polarization. The identical instrument,
including description and illustrations, but with additional
accessories available, is shown in Gaertner catalog for 1927,
the instrument thus appears to be a Gaertner product.
The manufacturer/vendor describe this instrument as an improvement
on the classic Norrenberg design. According to Turner* "This
design is attributed to Johann Gottlieb Christian Norrenberg
(1787-1862), who used the same elements in his polariscope of
1839." A Norrenberg instrument is shown as catalog number
571, Polariscope: Norrenberg, pg. 162 of Turner*. The major difference
between this design and the Norrenberg is that the former has
the various elements supported between a pair of vertical (usually)
brass rods attached to a wood base, thus the overall apparatus
would always be vertical.
Some contemporary/early descriptions of the polariscope (including
the Norrenberg) and its use are provided below:
Description: The instrument is incomplete, consisting
of a series of loose components mounted on a new half inch aluminum
rod and cast iron stand. There are two graduated (0-90-0-90-0
degrees by 5 degree increments), rotating, brass stages with
2 3/16" (55 mm) openings to accommodate windows etc. held
in place by stage clips. The stages are held in cast brass mounts.
Currently each has a brass disk with a centered eyepiece mounted
Nicol prism (one large and one small, held in cork); three 1
1/2" dia. lenses of varying focal length in cast brass mounts;
one #47183 tube holder with 47180 20 cm solution tube, and one
3 1/4" mirror in a cast brass mount. The lenses and collars
have 0.5" sleeves and thumb nuts to clamp onto a 0.5"
rod. The tube holder uses a standard 'v' type clamp as seen in
lab clamps to mount onto the rod. All cast pieces are finished
in black crinkle enamel paint. Machined brass parts (eyepieces,
stages) have a chemically darkened finish.
* Turner, Gerard L'E. The Practice of Science in the Nineteenth
Century: Teaching and Research Apparatus in the Teyler Museum.
The Teyler Museum, Haarlem (1996). pg 162.
