mirror for Jamin-type interferometer
Date1860-1880
Inventory Number1996-1-0699b
ClassificationInterferometer
Subject
Maker
Louis Jules Duboscq
French, 1817 - 1886
Inventor
Jules Célestin Jamin
1818 - 1886
User
Jefferson Physical Laboratory, Harvard University
founded 1884
User
Radcliffe College
1894 - 1999
Cultural Region
Place of Origin
Dimensions18.5 × 21.5 × 14 cm (7 5/16 × 8 7/16 × 5 1/2 in.)
box: 15.2 × 55.9 × 24.4 cm (6 × 22 × 9 5/8 in.)
box: 15.2 × 55.9 × 24.4 cm (6 × 22 × 9 5/8 in.)
Material
DescriptionThis instrument consists of a thick piece of glass with a mirrored rear surface, shaped as a parallelepiped and framed in metal. I t can pivot freely on a small rectangular support. The stand on which it rests consists of a vernier scale 10°- 0° - 10° divided every 30' and a silvered micrometer screw (divided from 0' -30' every 1') for fine adjustments. Underneath is an attachment so the apparatus could be put on an optical bench rail. There is also a perpendicular arm that was most likely used to add another lens in between the path of the light beam(s) coming in or out of the glass.
Signedon degree scale: J. Duboscq à Paris
Curatorial RemarksHoused in 2 separate containers : 1996-1-0699a is tied down to a blue board pallet, b-d are housed together in a blue board box with lid. SMS 12/5/2018
FunctionThis instrument was developed in 1856 by the French physicist Jules Célestin Jamin. He used it to measure the index of refraction of the air and water vapor at different temperatures.
A light source is focused first by a cylindrical lens and then shone onto a thick piece of mirrored glass (1996-1-0699b). The light beam is both reflected and refracted by the glass, creating two distinct beams. One of these then passes through the substance to be analyzed. Then the two beams are recombined by means of a similar thick piece of mirrored glass (1996-1-0699c) and the index of refraction is measured from the displacement of the interference fringes created by the substance under study.
In addition to the mirrors, CHSI has the stand (1996-1-0699a) and compensator (1996-1-0699d).
A simple explanation and an image is found on the following website.
A light source is focused first by a cylindrical lens and then shone onto a thick piece of mirrored glass (1996-1-0699b). The light beam is both reflected and refracted by the glass, creating two distinct beams. One of these then passes through the substance to be analyzed. Then the two beams are recombined by means of a similar thick piece of mirrored glass (1996-1-0699c) and the index of refraction is measured from the displacement of the interference fringes created by the substance under study.
In addition to the mirrors, CHSI has the stand (1996-1-0699a) and compensator (1996-1-0699d).
A simple explanation and an image is found on the following website.
ProvenanceJefferson Physical Laboratory, Optics Lab, pre-1940; Optics Lab in Byerly Hall, Radcliffe College, circa 1940-1964; transfer to CHSI in 1964.
Historical AttributesThis interferometer was used in the Optics Lab of Radcliffe College, which was situated in Byerly Hall. Many of the instruments in the Radcliffe laboratory were supplied in about 1940 by the Optics Lab of the Harvard University Physics Department, which was located in the Jefferson Physical Laboratory.
Louis Jules Duboscq
Date: 1860-1880
Object number: 1996-1-0699d
Louis Jules Duboscq
Date: 1860-1880
Accessories: mirrors (2) (separately cataloged as 1996-1-0699c and 1996-1-0700); compensator (1996-1-0703a)
Object number: 1996-1-0699a
Louis Jules Duboscq
Date: 1850-1880
Accessories: RAPPORT FAIT A L'ACADEMIE ROYAL SCIENCES SUR UN NOUVEL HELIOSTAT, Presente par M. SILBERMAN aine. (in instrument file folder)
Object number: 2000
Louis Jules Duboscq
Date: 1850-1880
Accessories: cardboard cover for prism (2)
Object number: 1997-1-1680
Louis Jules Duboscq
Date: 1850-1880
Object number: 1997-1-1571
