33 
not at my disposal, I have tried to find the series by means of my 
model, somewhat led by the estimations of the intensity given by 
Exner and Hascnex’). As these authors give widely divergent and contra- 
dietory differences from those of Karser and Runer ’), I have thought 
that I ought to prefer the former, because they extend over the 
whole of the spectrum observed by them. 
The obtained results follow. 
I must not omit mentioning that besides the said estimations of 
the intensity, also the constant frequency differences found by Kayser 
and Runrer ®) have furnished a first basis for my investigation. 
In the spectrum of Zn I have found a series which is represented 
by the formula : 
109675.0 
10° Al = 45307.40 — ———______ 
(a + 1,651360 — 657,42 JI} 
Peal Weer 
the results of which are: 
I LE 2 = = nn n EE ae ae Sn 
x dw AD wb Ss ae Intensity 
1 | 3655.92*) | 3655.92 0 003} 5 
2 | 2785.14 2785.14 0 0.03 3 
3 | 2524.05 2524.05 0 0.05 | 1 
4 | 2408.27 *| 2408.71 —0.44 0.03 i 
No more terms have been observed of this series, which need not 
astonish us, if we consider that in their tables Exnpr and HAscHrEK 
indicate by 1 the lines of the least intensity, and that therefore the 
following lines have probably been too faint. Now this four-term 
series would have little conclusive force, if it was not in con- 
nection with other series, which I have called Translation series in 
my Thesis for the doctorate, because they are obtained by a pure 
y-translation of the curve, and so only differ in their asymptotes. 
Such translation series are easily shown, as I have proved there, in 
the spectra in which series are known. By a translation 5187.03 
(one of the two differences of frequency discovered by Karser and 
1) Die Spektren der Elemente bei normalem Druck, II, p. 232 and 235. 
2 le. 
A 
4) Exner and Hascuex, |. c. 
Proceedings Royal Acad. Amsterdam. Vol. XV. 
