spectral adaptometer
Date: circa 1960
Inventory Number: 2000-1-0007
Classification: Visual Apparatus
Subject:
Maker: George Wald (1906 - 1997)
User: Ruth Hubbard ? (born 1924)
Maker: Biological Laboratories, Harvard University (founded 1932)
Maker: (transformer) Jefferson Electric (1915-present)
Maker: (mercury lamp) General Electric Company (1892-present)
Maker: (shutter) Ilex Optical Company (fl. 1910 - 1960)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
35 × 67.4 × 36.5 cm (13 3/4 × 26 9/16 × 14 3/8 in.)
DescriptionThis object is black and box-like. It uses a high pressure mercury arc as the source of light. It consists of two compartments. The front compartment contains the fixation apparatus (midget lamp mounted on a brass stem that is held in a ball joint) and a 6-volt transformer in series with a rheostat. The divider between the front and the back compartments holds the ground-glass screen, a sheet-wood shield with an opening at the center and drawn a grid of concentric circles, and a removable metal diaphragm. The back compartment contains the light source housing (capillary mercury arc, a pair of quartz lens, and a Corning 738 filter), a pair of complementary annular neutral wedges (controlled by the rotary dials at the rear), a photographic shutter (tripped by a string which runs to a pull-ring at the rear), and a sliding carriage which holds two color filters. In addition, there is a side door that opens into the wedge area, two rubber tubes from the light source, two plugs (one from the light source and the other from the transformer in the front compartment), and a lid (with ten air holes at the rear end) that covers the machine.
For a complete description of the machine, see ref in file: George Wald, "The Spectral Sensitivity of the Human Eye," Journal of the Optical Society of America 35, no. 3 (1945): 187-196.
For a complete description of the machine, see ref in file: George Wald, "The Spectral Sensitivity of the Human Eye," Journal of the Optical Society of America 35, no. 3 (1945): 187-196.
Signedon the 6-volt transformer that operates the midget lamp: Jefferson Electric MF, Co.;
on the capillary mercury arc found within the light source housing: General Electric 100W AH-4;
on the photographic shutter: ILEX OPTICAL CO. Rochester, N.Y., No.1. Universal
on the capillary mercury arc found within the light source housing: General Electric 100W AH-4;
on the photographic shutter: ILEX OPTICAL CO. Rochester, N.Y., No.1. Universal
FunctionAn adaptometer is an instrument used to measure the eye's sensitivity to various light thresholds. This spectral adaptometer - designed to be rugged and portable - was used in human spectrosensitivity function studies. A research subject would look into the rubber eye-piece and monocular measurements could be taken regarding spectral sensitivity.
For more information about spectral sensitivity, see here.
Using a high-pressure mercury arc (lamp) as a source of light, color-filters were used to emit particular wavelengths of light. This light was carefully directed toward the subject's eye, allowing for measurements to be made regarding light sensitifity in different regions of the eye which contain different types of receptors (e.g. cones and rods).
For results obtained by the instrument, see reference in instrument file: George Wald, "Human Vision and the Spectrum," Science 101, no. 2635 (1945): 653-658.
For more information about spectral sensitivity, see here.
Using a high-pressure mercury arc (lamp) as a source of light, color-filters were used to emit particular wavelengths of light. This light was carefully directed toward the subject's eye, allowing for measurements to be made regarding light sensitifity in different regions of the eye which contain different types of receptors (e.g. cones and rods).
For results obtained by the instrument, see reference in instrument file: George Wald, "Human Vision and the Spectrum," Science 101, no. 2635 (1945): 653-658.
Historical AttributesProf. George Wald, Higgins Professor of Biology, designed and made earlier versions of this machine. But later versions such as this particular machine were designed by him and made in the Biolabs machine shop.
Curatorial RemarksPower cord might indicate that the instrument was built at an earlier time or since it was shop made, they used whatever material they had at hand.
Primary SourcesThe following articles are located in the instrument file:
George Wald, "Human Vision and the Spectrum," Science 101, no. 2635 (1945): 653-658.
George Wald, "The Spectral Sensitivity of the Human Eye," Journal of the Optical Society of America 35, no. 3 (1945): 187-196.
George Wald, "Life and Light," Scientific American 201, no. 4 (1959): 92-108.
George Wald, "Human Vision and the Spectrum," Science 101, no. 2635 (1945): 653-658.
George Wald, "The Spectral Sensitivity of the Human Eye," Journal of the Optical Society of America 35, no. 3 (1945): 187-196.
George Wald, "Life and Light," Scientific American 201, no. 4 (1959): 92-108.
ProvenanceGift from Dr. Ruth Hubbard, Department of Molecular and Cellular Biology, Harvard University.