This is a simple three-armed brass spectroscope with one glass prism, on a black iron tri-leg base. It was used by William Francis Hillebrand (1853-1925), an American chemist with a PhD from the University of Heidelberg who analyzed a vast array of mineral samples for the U.S. Geological Survey. In 1890, Hillebrand found that when crushed uraninite was dissolved in sulfuric acid, this uranium-bearing rock emitted a gas that he and his colleague William Hallock identified as nitrogen. When the British chemist, William Ramsay, analyzed similar rocks in 1895, he attributed the spectral lines to argon. William Crookes, however, realized that some of the lines were caused by helium, a substance hitherto found only in the sun. That meant that this instrument captured the first evidence of terrestrial helium.
Ref. F. W. Clarke, “Biographical Memoir of William Francis Hillebrand,” National Academy of Sciences Biographical Memoirs 12 (1925): 43-70.
Currently not on view
Object Name
date made
late 19th century
overall: 10 1/2 in; 26.67 cm
ID Number
catalog number
accession number
Science & Scientific Instruments
Science & Mathematics
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
U.S. Geological Survey

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