There he also kept an astronomical regulator, heliostat, spectroscope, diffraction gratings, microscope with micrometer, balance, thermometers and barometers.
For example, spectrograph and spectroscope have basically the same meaning, and in an astronomical context metallicity and abundance are also synonymous.
These three lines can be observed superimposed on the white continuum using a hand spectroscope, for light emitted by the usual white fluorescent tubes.
