Edison Projecting Kinetoscope
<p><strong>This picture should be rotated 90 degrees clockwise to show how the instrument was actually used. This kinetoscope was manufactured by Edison Mfg, Co, Orange, N.J., USA. around 1902. Continuous 35mm film wrapped around the reel, and turning the crank runs it in front of a light source to project the picture out through the lens in the brass protrusion. The lens was made by Bausch and Lomb. This is number 6030. Edison patented this model in the 1890s.</strong></p>
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Voigtlander Vag Camera
Optics
<strong>Manufactured about 1920 by Voigtländer & Sohn AG of Braunschweig, Germany. A folding plate camera using a 6x9cm film back. It has a Voigtländer Anastigmat Voigtar 105mm f/6.3 lens set in a IBSOR DDR shutter made by AGC and having the AGC trademark (a symbol of three half-open shutter blades). The camera has a spring loaded bed, full twist and rise for the front lens assembly (with indents at “standard” intervals), a unique folding viewfinder and a large fold up sport finder. Its leather carry handle is embossed with “Vag” in Voigtländer’s unique script. <br /></strong>
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Theolodite
Optics
<strong>An optical instrument used to measure angles in surveying, meteorology, and navigation. The earliest theodolite consisted of a small mounted telescope that rotated horizontally and vertically. Washington and Lee taught surveying in the mid-19th century</strong>
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Prisms
Optics
<p><strong>Prisms have been standard laboratory equipment since Isaac Newton used one in 1666 to study the nature of the spectrum.</strong></p>
<p><strong>Most or all of these prisms were made by Duboscq in Paris.</strong></p>
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Achromatic Prism
Optics
<strong>The three prisms hanging from the brass stand may be folded up in pairs to demonstrate achromatism (no color separation) or constant deviation (no color dependence of the angle of minimum bending of light.) These were made by Lerebours et Secretan of Paris, and are listed at 50 francs in the 1853 catalogue.</strong>
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Newton's Rings
Optics
<strong>This device demonstrates “Newton’s Rings,” colorful interference fringes caused by a thin air layer first discussed by Isaac Newton in a communication to the Royal Society in December 1675, and presented an expanded account in his book "Optics" (1705). The original observation was first made with a wedge-shaped air-gap between the surfaces of two prisms, but later used the now-standard technique of pressing the convex surface of a lens against a flat glass plate.</strong>
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Heliostat
Optics
<strong>The heliostat takes light from the sun as it tracks across the sky, and redirects it in a fixed direction. To accomplish this, the light is reflected from a mirror that reproduces the motion of the sun, except at twice the rate. Although he did not invent the heliostat, the Dutch physicist William Jacob s'Gravesande gave it first prominence through mention in his 1742 textbook by. He coined the word from the Greek words for “sun” and “stationary.” Pictured is a Silbermann-type heliostat made by instrument manufacturer Duboscq.</strong>
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Absorption Cell
Optics
<strong>These glass spheres were used to contain gases such as iodine, bromine, and hypo-nitrous acid in order to study their light-absorption properties, i.e. their absorption spectra. Light shown on the cell passed through the glass and was absorbed by the gas differentially at different wavelengths. The spherical cells are listed in the 1888 "Illustrated Catalogue of Instruments used in Physical Optics" published by James W. Queen and Co. of Philadelphia at $7.00.</strong>
Property of the W&L Physics & Engineering Department