Duboscq Colorimeter

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Louis Jules Duboscq, a French instrument maker, made a colorimeter for a professor of industrial chemistry at the Commercial College in Paris in 1854. Duboscq's was not the first colorimeter on the market but it was, he would later claim, the first that allowed for the simultaneous color comparison of two liquids. Duboscq described an improved version to the French Academy of Sciences in 1868, noting that it was suitable for the analysis of colored materials for commercial purposes. That instrument had two glass tubes, one for a standard solution and the other for the sample to be analyzed. Light was reflected by a mirror at the bottom up through the tubes, refracted by a set of prisms, and viewed through an eyepiece. Identical glass plungers in each tube allowed the operator to adjust the height of the column of the liquids until the intensities appeared the same.
The Duboscq colorimeter became much more important after Duboscq's death in 1886 than it ever was during his lifetime, especially among biochemists who found that, in conjunction with suitable reagents, it offered an efficient and effective technique for identifying foreign substances in bodily fluids. Several French and German firms were making Duboscq and modified Duboscq colorimeters by the early years of the 20th century and Americans followed suit when World War I limited the supply of European goods coming into the United States.
Bausch & Lomb's first Duboscq colorimeter, introduced in 1920, followed the French optical design but the mechanical elements were changed: the base and frame were made of heavy castings; the rack and pinion were so arranged that the operating heads were always in a fixed position; the cups were made of ground glass cylinders and plates and encased in heavy metal; and there were adjustable verniers.
Bausch & Lomb later described their colorimeters as "instruments of precision, which will meet the most exacting requirements of the analyst" and noted that they would serve "where speed and accuracy are essential."
This example is marked "BAUSCH & LOMB OPTICAL CO. ROCHESTER, N.Y. U.S.A. NO. 4860." It is of the 50 mm size (that is, the glass tubes are 50 mm high), and may date from the 1930s. The National Bureau of Standards transferred it to the Smithsonian in 1965.
Ref: D. J. Warner, "The Duboscq Colorimeter," Bulletin of the Scientific Instrument Society 88 (2006): 68-70.
John T. Stock, "The Duboscq Colorimeter and its Inventor," 71 (1994): 967-970.
Currently not on view
Bausch & Lomb Optical Company
place made
United States: New York, Rochester
Physical Description
brass (overall material)
steel (overall material)
overall: 40.7 cm x 16 cm x 14 cm; 16 1/32 in x 6 5/16 in x 5 1/2 in
case: 38 cm x 18.5 cm x 17.5 cm; 14 15/16 in x 7 5/16 in x 6 7/8 in
overall in case: 14 7/8 in x 7 9/16 in x 6 7/8 in; 37.7825 cm x 19.20875 cm x 17.4625 cm
ID Number
catalog number
accession number
Credit Line
National Bureau of Standards
National Bureau of Standards
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Medicine and Science: Chemistry
Measuring & Mapping
Data Source
National Museum of American History


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