_ : : ■ z?.i> :z~ 
a. 
b. 
c. 
<7. 
«W 

3 9 
391 
38 
_ 
&S--:. 
381 
33 Q 
S* 
394 
: _ 
aao 
Prof. E. W. Wood on the 
the green cadmium-line 5086, which, as I showed in the 
previous paper, consists of a number of regularly spaced 
doublets. 
The blue lines of the cadmium lamp were cut off by a 
screen of nitroso-diniethylaniline. In more recent work a 
screen composed of a concentrated solution of a neodymium 
salt has been found to work better. 
The wave-lengths of the lines excited by the 5086 stimu- 
lation are given in the following table : — 
T 49690 a 
i 75-0 b 
'•: " 
' 5013€ : 
150521 
r :•:*■■■ >•: 
ISb 
{ 5130-36 3fr€ " 3T1 
5159-0 c 
f 51644 a 
I 5169*5 b 
5195-2*2 
5199-9 e 
5202-4 o. 
1237-9 e 
:-2 : "S-.:« •- 
'.7-VOc 
5305-6* 
In this table we see that in addition to the doublets which 
I have spoken of. and which are bracketed, there are a 
number of other lines. The lines which belong to the same 
series of equidistant lines are indicated by letters. We find 
in this case that as we approach the upper limit of the series, 
other lines appear on the short wave-length side of the line 
or lines at the upper end. a new series starting where the 
old one leaves off. This same thing occurs in many other 
instances, as in the resonance spectrum excited bv the barium 
line 4934. 
It is a little difficult to express in words exactly how these 
lines come in. and a much better idea can be gained by 
applying a pair of compasses to the chart and spacing olf 
the series, and noting how the lines of the new series appear 
on the short wave-length side of the lines which are being 
spaced off. 
I have given the differences between the wave-lengths 
the lines of the different series, a. L. c. and t in a separate 
table. The line d appears to be isolated. 
