Band and Line Spectra of the same Metallic Elements. 95 
8:9 mlgrs. present. Ramage has shown that, with the exception of 6103-84, the 
lines in the first subordinate series have wave-lengths, which differ by + 0:28 to 
+ 0:70 from those in the are as measured by Kayser and Runge, and that this 
element appears to behave exceptionally in this respect; hence his numbers are 
quoted. 
Porassium. 
Pure dry potassium nitrate was dissolved in water, in the proportion of 
2°6 grs. to 100 ¢.c. of the solvent. This is equivalent to 1 gr. of potassium. 
Absolute alcohol and water were added alternately until the volume of the solution 
became 500 c.c. without precipitating any of the salt: 1 ¢.c. of this solution thus 
contained 0:002 gr. of potassium. Edwards’ Isochromatic plates were used. 
With the first quantity of substance, a somewhat complicated spectrum was 
obtained. 
Quantity of Description of the Spectrum photographed. 
otassiwm. 
0:5 gr. A triplet AX 5832°25, 5802°12, 5782°74. 
A band of diffused rays from \ 5782-74, increasing in inten- 
sity to ) 5554, and decreasing to \ 5376. A triplet AA 5376, 
9399°96, 5840°17. ‘Two lines Ad 5217, and 5124. A strong band 
from 4895, continuing with the same intensity to the fine pair 
of lines of potassium, and a third one belonging to manganese, 
seen in the violet AA 4047°39, 4044°33, and (4041°5 manganese), 
continuing with gradual weakening to about dX 3300. In this 
band a line appears ) 3447°56. 
0-004 gy 
0-0036 21 Feeble bands are seen corresponding to those described above. 
0-0032 e A strong line \ 4047°39 and a feeble line \ 3447-56. 
0:0024 gr The line \ 3447:56 has disappeared, and the band of 
continuous rays is very feeble. 
00020 gr. Line \ 4046 is strong, but is really composed of 4047:39 and 
0:0016 er 404433, and the manganese line (4041°5); the first and the last 
0:0012 gt are the most prominent. 
0:0006 gr 
00004 gy | a aoe. 
0-0002 gr. f The line alone visible is \ 4047°39. 
0:0000016 gr. The line \4047:39 is still visible, but it disappears when one- 
0:0000008 gr.) half the last quantity, or 0:0000004 gr., of potassium is taken. 
R 2 
