XIV. On the quantitative analysis of certain alloys by means of the spectroscope

Abstract

In certain researches on Spectrum-Analysis, the results of which have already been communicated by one of us to the Royal Society, it has been shown that the spectroscope may be employed to distinguish minute differences in the composition of certain alloys. We have therefore instituted a series of experiments with the view to ascertain the degree of accuracy of which the method is capable, and now submit the results which we have already obtained. In the researches above referred to, an electric-spark-current was used to volatilize the alloy under examination, and the image of the spark was thrown by means of a lens on the slit of a spectroscope; the phenomena observed indicated that a change in the percentage of any constituent of a metallic alloy ordinarily causes a change in the character of lines exhibited in the resulting spectrum, in length, brightness, or thickness; and the percentages of the constituents, it was stated, might be determined by comparison with the spectra of pieces of metal of known composition.