Band and Inne Spectra of the same Metallic Elements. 103 
The spectrum of copper is also given in detail as photographed. Its behaviour 
is very similar to that of the alkaline earth metals; that is to say, almost to the 
last trace of substance in the flame the spectrum is a band spectrum with two lines. 
The bands in the spectrum are also of two kinds, the composite bands apparently 
composed of fine lines, and the simple bands of diffused rays. 
This spectrum disappears when there is less than 6 mlgrs. of copper in the 
flame. Photographed with Wratten and Wainwright’s panchromatic plates. 
Copper. 
Oxyhydrogen Flame Spectrum. 
A standard solution of cupric nitrate, Cu(NO,).* 3H,0, was made by dissolving 
2°416 grs. of the salt in 100 ¢.c. of water. 
Weight of 
Copper. 
0:25 er. A fluted band spectrum, characteristic of metallic copper, is visible 
from 5745, increasing to greatest intensity about 5520, and 
extending with diminishing intensity to its disappearance about 
44300. <A pair of lines is visible in the band AA 8274 and 38247. 
0:01908 gr. A strong band extends from \ 5560 to \ 5605. The two lines 
AX 8274 and 3247 are visible in the band. 
0:01272 gr. The band is feeble. The lines \A 38274 and 3247 are visible. 
0:00636 gr. The band is almost invisible. The two lines are still visible. 
0:00318 gr. Nothing visible. 
The spectra of the alkali metals at the highest temperature of the oxyhydrogen 
flame, and those obtained from the are, more nearly resemble each other than do 
any other two spectra yielded by the same element. For instance, the following 
doublets in the sodium spectrum have been photographed as single lines from a 
variety of salts placed in the flame :— 
6161-1 ans 5688°3 saa pe 4669°4 3301°1 
ee | 5890:2 ee 5149-2 4979°3 ae ea | 
But by reducing the quantity of substance in the flame, some of the lines have 
been photographed as double, for instance, the two yellow lines; where the space 
between them measured 0°45 mm., the difference in wave-lengths was 6 Angstrém 
5 2 
