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FunctionThis hollow prism was filled with a solution of carbonic disulphide, which gave a large dispersion of light passing through it. The stuff reputedly smelled awful and had a temperature-sensitive index of refraction, but this type of prism was less expensive than one of solid optical glass. The prism was used for spectroscopy.
Historical AttributesIn the 1860s and 1870s, the firm of Alvan Clark and Sons made quite a few carbonic disulphide prisms and spectroscopes for the Harvard physics and chemistry departments. They also made spectroscopes for the Harvard College Observatory, and may have made this example.
ProvenanceHarvard College Observatory; George R. Agassiz Station; transferred to CHSI in 1969.