Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

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Bunsen Spectroscope

Bausch & Lomb Co.
Humboldt State College, 1957
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The oldest optical method for chemical analysis, Bunsen and Kirchhoff introduced spectroscopy as a laboratory method in 1860. The basic features of the spectroscope (or spectrometer) include a slit and collimator to produce a parallel beam of light which then falls on the dispersive element (a prism). The resulting spectrum is then observed through a telescope. In the Bunsen spectroscope the relationships of the telescope and collimator are fixed at angles appropriate to viewing the visible spectrum through a prism. The telescope may be adjusted slightly to center appropriate segments of the spectrum. The third tube is a scale telescope which is used to project an image of a scale. The image is reflected off the face of the prism in such a way as to superimpose itself onto the spectrum for ease of measurement. This example is a student instrument for the determination and analysis of spectra using either a prism or grating.
Some early descriptions of the spectroscope and its use are provided below:


The instrument stands 15" high at its highest point. The legs of the tripod extend 6" from the center of the column. The prism box is 4" O.D. and 1 3/4" high. The prism table is mounted off-center, with three screws for leveling against coiled tension springs. The cast iron stand and the prism box are finished in black crackled lacquer. There is a 60° prism on the prism table. The telescopes and collimator are each an inch in diameter. The telescope may be rotated though a short angle and clamped in place via a screw clamp to the column. According to the catalog description the objective lenses of the telescope and collimator are of 125 mm focal length, the ocular is 14x, and the scale is 15 mm long. The telescope, collimator, scale telescope and lid of prism box are all finished in gloss black enamel. There is a yellow decal on the column: STATE OF CALIFORNIA / HUMBOLDT COLLEGE / 15782.

A manual for the spectroscope was stored in the HSU analytical chemistry prep-room file drawer.


According to HSU property records this instrument was purchased in 1957 for $140.40. Bausch and Lomb published a brochure (copy in Smithsonian NMAH Library) in 1932 entitled New Bunsen Spectroscope, apparently introducing this style of instrument to their line at this time.

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HSTC (1921-34)
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HSC (1954-1973)
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HSC (1935-1953)

HSC 1956-72 Instrument Collection

© R. Paselk
Last modified 13 August 2010