ABSTRACT
In the chapter, the authors shall confine people to the application of a method to the detection of the metals of the alkalies and alkaline earths, and to the illustration of the value of the method in a series of examples. The bright lines in the flame-spectrum are seen most plainly when the temperature of the flame is highest, and its illuminating power least. Between the object-glasses of the telescopes B and C is placed a hollow prism, F, filled with bisulphide of carbon, and having a refracting angle of 60 degrees. The method of spectrum-analysis not only offers, as the people flatter themselves the authors have shown, a mode of detecting with the greatest simplicity the presence of the smallest traces of certain elements in terrestrial matter, but it also opens out the investigation of an entirely untrodden field, stretching far beyond the limits of the earth, or even of a solar system.
