WITHIN the last fifteen years the spectroscopic equipment applied to the study of both laboratory and celestial investigation has been very materially modified both in dispersive power and design. In the early nineties there were very few of the 21.5-feet Rowland concave grating spectrographs in regular commission for terrestrial research, and it is probably safe to say that no stellar spectrographs were in use giving direct spectra comparable in dispersion with Rowland's solar spectrum.