162 
The four mentioned curves are all four the same, but each in 
another position. For z=1.2.3 the curve y= Pz, yields the values 
P,, P,, P,, which indicate three P-asymptotes (— — —) in the 
YOX-plane. In the same way the S,-asymptote (_.—.—), the D,- 
asymtote (__..__..__) and the F,-asymptote (—) is obtained. In 
other spectra D,,S, ete. can also appear as asymptotes. We now 
find the following curves in the YOX-plane, in which I have now 
once more given the meaning in the new and the old nomenclature. 
y= SP, Principal series with S,-asymptote. Principal series. 
nt ie ARD se a a en ged Subordin. series. 
y == BD: Difiuse 5 pel, 5 1st te 
Oe Re Vk Principal ae ee ze a _ 3rd 55 33 
y = PF, Fundamental _,, pe a: Comb : 2p——mAp. 
y= PS, sharp % ae oa FS Comb : 3p—ms. 
y= P,D, Diffuse > pay ze = Comb : 3p—-md. 
y= P,S, Sharp Ë ad 5 5 Comb : 4p—ms. 
y= P,D, Diffuse ad EE Bf Comb : 4p—md. 
y— D,F, Fundamental ,, , ,, dy. 5 Bergmann series. 
y= FF, Fundamental „ epee e Comb : 5 —mbp, 
and further the curve y= ol, so this is the original curve on its 
original system of axes. 
In the above table I have arranged the curves according to their 
asymptotes. We can now also easily arrange them in Translation 
groups. 
„ESP, and y= Lae form together the Translation group P 
y= Pes y ol ape y= P‚Sr ” ” ” ” ” 
g— PDs y= EDEN PD Fe 2 ze ic Se 
RN =DE Een - rf dE Nba 
All the curves representing series which belong to one and the same 
Translation group, have been indicated in the same way, so: 
All the members of the Translation group P by — — — 
All the curves indicated in the same way can be made to cover 
each other by merely a translation // Y-axis. 
If we wish to make a spacial representation of the whole system 
of series, we need only think the YOZ-plane rotated back to its 
original position, then the different curves will lie in different planes 
