| Polarization by reflection was discovered
in 1808 by Etienne Malus (1775-1812). Malus, who had been doing experimental
work on double refraction while working on a theory of the effect, observed
the light of the setting sun, reflected from the windows of a nearby window,
through a crystal of Iceland
Spar. As he rotated the crystal, the two images of the sun became alternately
stronger and weaker, though there was never complete extinction. Almost
at once he repeated the experiment under controlled conditions, and found
that the angles at which complete extinction of the reflected ray was obtained
for water and glass.
A Polarimeter is a device for studying a transparent sample between crossed polarizing devices. Jean-Baptiste Biot (1774-1862) developed the polarimeter at the right, which was made by Soliel/Duboscq of Paris ca. 1850. The polarizer on the right-hand side uses a single plate of glass, while the analyzer on the left uses a pile of glass plates. The sample is held between these two devices. This apparatus is at Dartmouth College. |
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The Polariscope at the left is in the Millington/Barnard
Collection at the University Museum of the University of Mississippi.
It is unmarked, and of the basic (and least expensive) type, using polarization by reflection for both the polarizer and the analyzer. |
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The handsome polarimeter at the left is in the collection
at the Smithsonian Institution. The sample is placed on the top of the
cubical wooden box. The incoming light is polarized either by the diagonal
glass plate or one inside the box. The analyzer is of glass plates inside
the wooden drum.
At the right is a pair of polarizing glass plates which I found in the apparatus demonstration room at Glasgow University during a 1978 visit. As I picked it up, I had the thought that Lord Kelvin had used it in his lectures a century earlier. |
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At times it is necessary to have a wide field of view for samples
held between crossed polarizing devices. Before the introduction of sheet
polarizers, the practical solution to the problem of producing a linearly
polarized beam of large diameter was the use of polarization by reflection,
with a Nicol
prism used as an analyzer.
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Seven devices of this type are shown; these are sometimes named after Edward Pickering (1846-1919), who introduced laboratory work in physics to Harvard University. The example at the Judson Collection is by Stoelting of Chicago, and cost $7.50 in 1912. The arm on the device was intended to carry a magnifying lens. The polariscopes with the notches taken out of the corners of their upright wooden plates were made by Queen of Philadelphia, and cost from $20.00 to $45.00 in 1887. The remaining device is probably also by Queen, and cost in the $6.00 to $15.00 range. Queen also sold sets of samples to be used with the device. |
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| The small
polarimeter at the right was made by Alfred L. Robbins-Martin Co. of Chicago.
The base is only 32 cm long. The glass plate from which the polarized light is reflected is back-painted in black; the diffusing glass is missing. The small-diameter Nicol prism was in working condition when it was tested agains sunlight reflecting from a waxed wooden floor. The device is in the Greenslade Collection. |
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This Pickering-type polarimeter is in the Greenslade Collection. The name of the Ziegler Electric Company of Boston is stamped into its side. However, it has the same form, including the ornamentation on the upright brace, as the polarimeter listed in the 1916 catalogue of the L.E. Knott Apparatus Company of Boston, who listed it at $8.00. However, the Knott example does have a graduated scale for the rotation of the Nicol prism. This one, lacking the scale, is properly a polariscope. |
| The apparatus at the right was purchased
by the United States Military Academy in 1829, probably from Lerebours of
Paris, and was used for the determination of Brewster's angle for liquid or
solid samples.
A beam of unpolarized light from a small diameter source is defined by a hole in the bracket at the end of the pivoted arm, and the reflected light is viewed through the eyepiece, which contains a calcite crystal. The calcite analyzer produces two images of the hole in the bracket, and at Brewster's angle for the sample one of these disappears. The reflecting surface is set parallel to and along the 90° line of the divided circles by the adjusting screws. The eyepiece can be moved outward to examine the light reflected from liquids in the square pan next to the solid surface. This apparatus is now at the Smithsonian Institution. |
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The polarization apparatus at the left is a Dartmouth
College, and was made by Widdefield and Co. of Boston. This is the only
piece of apparatus I have seen by this maker.
At the bottom is a rectangle of black glass to produce light polarized by reflection. |
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This a generalized apparatus for studying polarization
phenomena in the Garland Collection of Historical Physics Apparatus at
Vanderbilt University.
It is listed in the 1885 Duboscq catalogue as "Apparatus of Jules Duboscq, for showing all of the phenomena of linear, circular, elliptical, chromatic and rotary polarization, and investigating crystals with one optical axis and with two optical axes." Many other parts are stored in the box on which the apparatus stands. If you wanted to buy one piece of apparatus to demonstrate and investigate polarization phenomena, this was the one!
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| The polarimeter at the right is in the Millington/Barnard
Collection at the University of Mississippi.
It was probably bought during the second half of the 1850s from Lerebours et Secretan of Paris by Prof. Frederick Barnard. It is listed in the 1853 L&S catalogue as Arago's polariscope and was designed to demonstrate the laws of light polarized by reflection and refraction. The cost was 100 francs, or about $20. Arago was Dominique François Jean Arago (1786-1853), the French astronomer and physicist who also introduced J.L.M. Daguerre's invention of photography to the Academy in 1831. |
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This instrument, also in the University Museum
of the University of Mississippi, is listed in the 1853 L&S catalogue
as Biot's polariscope, and cost 340 francs (about $65) with all of its attachments
and samples.
Jean-Bapatiste Biot, who is best known today for the Biot-Savart law relating currents and magnetic fields, is the inventor of tourmaline tongs that are used to study polarization effects in small, thin samples. |
| This is an elbow polariscope fitting for a Leybold's
Universal Projection Lantern. It includes a series of polarization samples
including a butterfly, a parrot, a chameleon, a tulip and a forget-me-not.
In the catalogue of E. Leybold's Nachfolger published ca 1920, the apparatus
in the box adds up to $79.00.
This instrument is in the Jack Judson Collection at the Magic Lantern Collection in San Antonio, Texas. The collection also includes the Universal Projection Lantern with which it was designed to operate. |
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This is a polarized light attachement for
an optical disk.
The Central Scientific catalogue notes that the polarizer (on the left)
is a pile of transparent glass plates 6x10 cm. The analyzer is a rectangular
glass plate which is mounted to rotate on the optical axis of the apparatus.
The ground glass screen is used for the projection of the image, and the samples
are placed in the holder in the middle. The cost was $17.50.
This apparatus is in the Judson Collection in San Antonio, Texas; Kenyon College has another example |
