MR, W. CROOKES ON RADIANT MATTER SPECTROSCOPY. 
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calcium. The spectrum (fig. 15) was very brilliant, and but little inferior in sharp¬ 
ness to the spectrum given by a 50 per cent, mixture. 
Pig. 15. 
158. A mixture was now prepared containing 1 part of samarium to 1000 parts of 
calcium. Very little difference could be detected between the spectrum of this 
mixture and that of the last. The bands were, however, a little less sharp. Fig. 16 
shows the appearance of this spectrum. 
Pig. 16. 
159. A mixture containing 1 part of samarium to 10,000 parts of calcium. The 
resulting spectrum is shown in fig. 17. The bands are now getting fainter, the second 
Fig. 17. 
green band is fading out, and the continuous spectrum of calcic sulphate is getting 
brighter. 
Fig. 18. 
160. The next mixture tried contained 1 part of samarium in 100,000 parts of 
calcium. The appearance of the spectrum is shown in fig. 18. Here the green is 
4 z 2 
