714 
MR. W. CROOKES ON RADIANT MATTER SPECTROSCOPY. 
detected in the green band. The following experiments were continued; mixtures 
were prepared in the following proportions :— 
Samaria. 
Yttria. 
58 
42 
56 
44 
54 
46 
53 
47 
52 
48 
51 
49 
50 
50 
49 
51 
48 
52 
47 
53 
46 
54 
45 
55 
The results were almost identical with those yielded by the previous mixtures. 
The green band gradually condensed into two bands at 3133 and 3199 as the pro¬ 
portion of yttria increased ; the first green band was stronger than the other, and the 
wide orange band began to show signs of a wing on the side next the green. At this 
stage the spectrum nearly resembled the lead-samarium spectrum (145, fig. 6). Very 
little of the yttria spectrum could be detected, and the brilliant orange line stood 
out sharply in the whole series. 
In the next mixture—samaria 44, yttria 56—a faint band ^ 3038^, was visible by 
the side of the two green bands, in the position occupied by the yellow band of 
yttria. 
148. The experiments were continued, and the following mixtures were made and 
and carefully mapped :— 
Samaria. 
Yttria. 
43. 
57 
42 
58 
41 
59 
40 
60 
39 
61 
The faint line first observed in samaria 44, yttria 56, gradually got stronger, and 
there were also signs of a double green band in about the position occupied by the 
yttrium green. 
149. The change which had been rapidly coming over the spectra since samaria 43, 
yttria 57, was now nearly accomplished, and in the next trial mixture—samaria 35, 
