SPECTRUM ANALYSIS. 



285 



Fig. 106. The Spectroscope. 



rays are then refracted, and the image of the refracted rays 

 is observed through the telescope, B. In the instrument 

 here pictured, a third tube, D, contains a scale engraved on 

 a glass plate, and this being illuminated by the candle flame, 

 <7, can be seen at the same time with the spectrum ; one 

 face of the prism reflecting this scale through the telescope, 

 B, to the observer. 



402. Spectrum Analysis. The spectroscope, invented in 

 1859 by two distinguished Germans, a chemist (Bunsen) 

 and a physicist (Kirchhoff ), is of great importance to the 

 chemist, for it places in his hands a means for detecting 

 certain substances with great accuracy and extraordinary 



