EE 
Su 
ha 
“Also it shows conclusivel 
y 
159 | 
| R MH 8 
109675.0 109675.0 _109675.0 
(rte) (ater) | CEA 
109675.0 | 109675.0 109675.0 
rea) Cree SREP 
109675.0 109675.0 109675.0 
rai) Graney) AEN 
109675.0 109675.0 109675.0 
(rr EN ef ae (e+ F+ ey 
that such difference cannot be 0,5, 
a supposition, which has suggested the idea that the P and S are 
similar series, P with even numbers and S with odd’. 
About the Fr we may remark that f differs very little from a 
whole number, and that g becomes practically equal to zero. So 
the denominators differ very little from Od: 
After we have ascertained this, the designation of every spectral 
line is self-evident. We must, namely express in the designation, 
of what two. terms of what two series its frequency is the dif- 
ference. So the second line of the principal series is represented 
by S,—P,, the whole principal series by S,—P.v. So we may omit 
the sign — for simplicity, and write S, P, resp. S, Pe. 
A priori the following series are possible: 
Up to now only one or more lines have been observed of the 
series printed in big type. 
The series in column I we call Principal series. They form together 
a group of Translation series (cf. p. 157), and differ only in asymptote. 
A. Go pe kee 
I | Il | Ill | IV 
Pz Px Pz Sx Pz Dx Pz Fx 
Sz Px Sau Sx Sz’ Dx Sz Fx 
Ds Px Dz Sx Ds Dx Dz Fx 
Fs Px Fs Sx Fs Dx Fz Fx 
