Images(7)

polarizing microscope

Date1840-1860

Inventory Number1215

ClassificationPolariscope

Subject

Maker Jean Baptiste François Soleil 1798 - 1878

Maker Henri Jean Jacques Soleil died 1879

Cultural Region

Place of Origin

Dimensionsmicroscope: 30 × 11 × 11 cm (11 13/16 × 4 5/16 × 4 5/16 in.)
case: 11.5 × 25 × 14 cm (4 1/2 × 9 13/16 × 5 1/2 in.)

Material

Accessoriescarrying case; objective; double refraction ocular; substage polarizer; rotating stage plate; horizontal case; stage forceps; oculars (2)

DescriptionThe microscopic tube is held in place by a pillar, which is fixed on a heavy circular base. The pillar also holds the substage mirror (which has two reflecting faces) and the stage on which is attached a condenser and a Nicol prism (polarizer). The pillar moves up and down with a rack and pinion mechanism for coarse adjustments. The tube is composed of several lenses, which act as the analyzer (replacing a Nicol prism). When not in use, the instrument is stored in a box.

The box contains accessories, including a mineral specimen, "Plomb / carbonate", on a square slide also signed "Soleil / A Paris".

The box also contains a piece of paper with the following inscription (in French, with several spelling mistakes): "Polarisations Mikroskop von Soleil in Paris. Pour Observer la structure des Cristaux. On suprime le disperseur A et on le remplace par le disque de verre ci joint sur lequel on dépose les cristeaux a observer. On suprime ausi [sic] le tuyau B et on presise [?] la distence focale convenable pour chaque Observateur comme dans un microscope ordinaire. Dans lautre cas la distence focal[e] est la même pour tous les yeux[;] elle depend seulement de lepaiseur des cristeaux axes ou biaxes."

Signedon tube: SOLEIL / à Paris

Curatorial RemarksFrench physicist Etienne Louis Malus (1775-1812) discovered the polarization of light by reflection in 1808 and double refraction (bi-refringence) in crystals in 1810. The explanation of the first phenomena is a convincing demonstration of the transverse nature of light waves and leads to Malus' law, which describes the intensity of polarized light in terms of the square of the cosine of the angle of polarization. The polarizing microscope was devised by Giovan Battista Amici (1786-1863) around 1830. German chemist Johann Gottlieb Christian Nörrenberg (1787-1862) was the first to use a Nicol prism as an analyser with this form of apparatus (c. 1830-1840).

FunctionThis instrument would have been used to observe the polarization of light in meneral and other forms of samples, but not to measure the angle of polarized light when it passed through the specimen.

Sunlight (most likely) would be reflected from the plain substage mirror onto the condenser, in which there is a Nicol prism (polarizer), which would polarize the light and refract it upwards. This polarized light would encounter a specimen held in place on the stage. Light would go through the sample and up towards the tube and eyepiece, which has the analyzer (a combination of lenses). There is no graduated circle to measure the angle of rotation from the polarized light after it passed through the specimen.

For other types of polarimeters, see the following website.

ProvenanceDavid Wheatland purchased from Alain Brieux, Paris, November 11, 1963 (lot 13/8). Donated to CHSI February 2, 1964.