persed by said prism may be brought into coincidence with said aperture.
8. In an instrument of the character set forth, a dispersion prism and a telescope 5fixed against movement relatively to each other, means to direct a beam of light through said prism to said telescope, said telescope being provided with an ocular aperture, and an optical wedge mounted for 10sliding movement longitudinally of said telescope, said wedge being constructed and arranged to cause the longitudinal movement thereof to move the spectrum of said beam transversely across said aperture,
159. In an instrument of the character set forth, a dispersion prism and a telescope fixed against ‘movement relatively to each other, means to direct a beam of light through said prism to said telescope, said 20telescope being provided with an ocular aperture, an optical wedge mounted within said telescope for longitudinal sliding movement and arranged to bring any portion of the entire spectrum of the beam 25dispersed by said prism into coincidence with said ocular aperture,
10. In an instrument of the character set forth, a dispersion prism, and a telescope fixed against movement relatively to each 30other, means to direct a beam of light through said prism to said telescope, said telescope being provided with an ocular aperture, an optical wedge movable relatively to said telescope for selectively 35bringing any portion of the spectrum of the beam dispersed by said prism into coincidence with said aperture; and a scale and pointer secured respectively to said telescope and wedge for indicating directly the 40wave length of the light rays brought into coincidence with said aperture.
11. In an instrument of the character set forth, a dispersing prism and a telescope fixed against movement relatively to each 45other, means for passing a beam of light through said prism to said telescope, a sleeve mounted upon said telescope for longitudinal sliding movement and an optical wedge secured within said sleeve for 50causing the rays of light dispersed by said prismi to be deflected at an angle to the axis of said telescope.
12. In an instrument of the character set forth, a pair of reflecting. surfaces, 55arranged in spaced parallel relationship, a source of light located between said surfaces, means to vary the distances between said source of light and said surfaces, an optical prism arranged to collect a portion 60of the light reflected by said surfaces and to direct said light in a pair of substantially parallel juxtaposed beams along a predetermined path, and indicating means positively fixed and located relatively to 65said source of light and said reflecting surfaces, said indicating means being constructed and arranged to furnish a direct reading of the relative intensities of the beams incident on said surfaces and a sectored rotatable dise interposed between said70 prism and one of said surfaces to intercept a predetermined proportion of the light of one of said beams and thereby enable a micrometric reading to be obtained from said scale and pointer.75
13. In an instrument of the character set forth consisting of a spectrometer and a photometer, said photometer comprising a source of light, a pair of reflecting surfaces, and means to vary the relative positions of80 said surfaces and source of light, an optical prism to direct a portion of the light reflected by said surfaces to said spectrometer in a pair of substantially parallel juxtaposed beams, and said spectrometer comprising a85 dispersion prism and a telescope fixed against movement relatively to each other, and means to examine selectively portions of the spectrums of said beams, said means including an optical wédge mounted within90 said telestope for longitudinal sliding movement; said photometer and spectrometer each being provided with a graduated scale and a cooperating pointer constructed and arranged to furnish directly comparative95 data of the brightness and wave length of the beams incident on said surfaces.
14, In an instrument of the character set forth, a photometer and a spectrometer mounted upon a common support in fixed100 optical relationship to each other, said photometer including a source of light, a pair of reflecting surfaces, means for varying the distances between said source of light and said surfaces, and a scale and a pointer 105positively fixed and located relatively to said source of light and said surfaces, said scale being graduated to furnish a direct reading indicative of the relative intensities of the light incident on said surfaces; said 110spectrometer including a telescope and a dispersion prism fixed against movement relatively to each other, an optical wedge mounted for movement relatively to said telescope to enable any portion of the spectrum to be 115viewed selectively, and a scale and a pointer positively fixed and located relatively to said telescope and wedge, and being constructed and arranged to indicate directly the wave length of the light rays of the portion of the120 spectrum brought into view.
15. A spectrophotometer comprising a pair of reflecting surfaces, a source of light arranged between said reflecting surfaces and movable relatively thereto, a collimator,125 a ray directing prism to direct a portion of the light reflected by said surfaces in two substantially parallel juxtaposed beams into said collimator, a dispersing prism and telescope fixed against movement, relatively
