spark spectra of lead, tin, antimony, bismuth, and gold. 225 
\ 
Inten- 
sity 
1 IX/X 2 
3122-97 
1 
+ 1-72 s 
0 p 
- 1-65 s 
2913-68 
1 
+ 2-01 s 
0 p 
-1-98 s 
| Compare X 3898. 
2748-30 
6 
+ 2-17 s 
0 p 
-2-19 s 
| Compare X 3804. 
Runge and Paschen have shown that the constituents of some 
of the lines in the principal and subordinate series of Na, Cu, 
A g, Al, Tl, Mg, Ca, Sr and Ba belong to the same type in the 
character, relative intensity, polarisation and distance apart when 
represented on the same scale of vibration numbers*. Some 
of the constituents of the lines of the metals of this investiga- 
tion appeared to be very similar to several of those described by 
Runge and Paschen. The author has measured the separation 
of the constituents of the quadruplets arising from the lines of 
Cu 3274 and Ag 3383, when the latter were vibrating in the 
stronger magnetic field used in these experiments, and compared 
them with several of the divided lines of Pb, Sb and Au. The lines 
Cu 3274 and Ag 3383 of the principal series were divided into 
four constituents, and the type, intensity, polarisation and values 
of cZX/A. 2 are strictly comparable with similar lines of Na, Al, Tl, 
Mg, Ca, Sr and Ba. The following table is a summary of the 
comparison of the quadruplets arising from the metals investigated 
by the author, from which it will be seen that there is a definite 
relationship between lines belonging to the principal series of Cu 
and Ag (and, therefore, of Na, Al, Tl, etc.) and lines of Pb, Sb, 
and Au which have not hitherto been correlated in any law of 
series. 
Cu. 
3274 
Ag. 
3383 
Au. 
3029 
Pb. 
3740 
Pb. 
2873 
Sb. 
3722 
Sb. 
3638 
Mean 
+ 2-03 
+ 097 
0 
-0-97 
-2-03 
+ 2-05 
+ 0-96 
0 
-0-96 
-2-05 
+ 2-15 
+ 0-99 
0 
-0-99 
-2-15 
+ 2-00 
+ 0-95 
0 
-0-95 
-2-00 
+ 2-05 
+ 0-97 
0 
-0-97 
-2-05 
+ 2-21 
+ 1-01 
0 
-1-01 
-2-21 
+ 2-11 
+ 0-99 
0 
-0-99 
-2-11 
+ 2-08 s 
+ 0-98 p 
0 
- 0-98 p 
- 2-08 s 
Astrophysical Journal, Vol. xvi. 1902, p. 123. 
