Spectroscope. Hand worked brass astronomical spectroscope made to be used with two prisms. Telescope and collimator held in position by brass latticework frame. Telescope has an eyepiece illuminator with cross hairs employing a mirror. The vernier scale extends over about 80 degrees and has a drum attachment with a press button that could be used to mark a paper in the dark. The collimator also has a vernier slit adjustment, a periscope for alignment on a particular star, two small prisms for introducing calibration spectra above and below the main spectrum, an attachment for producing a calibration arc and directing the light into these two prisms for viewing, an adjustable cylindrical lens for producing even illumination of the slit from a point image. Cylindrical attachment for use with a large telescope. Inside wooden box are three eyepieces, two lenses, two parts of a small hand-held star spectroscope, and eleven prisms of differing glasses, several as matched pairs. The prisms are made from different types of glass containing chalk ('white flint), aluminium and calcite, each one listed with its specific gravity ('S.G.') as a measure of optical density.