161 
dan Symbol Old appellation or symbol 1) 
Principal Py Pe Comb *): 2p — 3p; 2p — 4p; 2p —5p; 2p — 6p; etc. 
series 
(P-series) Se Principal series. 
Sharp Pr SE 2nd Subordinate series. 
series P, Sx Comb: 3p — 1.5s; 3p —2.5s; 3p —3.5s. 
(S-series) Py St Comb: 4p — 2.5s; 4p — 3.5s. 
Pr De Ist Subordinate series. 
Diffuse Ps Dr Comb: 3p — 4d; 3p —5d; 3p — 6d. 
series P3 Dx Comb: 4p — 4d; 4p — 5a. 
(D-series) > Dr Comb: 1.5s —3d; 1.5s — 4d; 1.5s —5d; 1.5s — 6d. 
reyes Be 9 Comb: 32.5s — 3d. 
Pr Fa Comb: 2p—4cp; 2p—5sp; 2p—6rp 
Filament S Fa Comb: 1,5s—6/ p. 
: D;. Fx Bergmann series. 
series 
sene Di Fa Comb: 4d— 4/p; 4d—5vp. 
N N WN 
Fir Comb: 54 LP; 5 63° 
vernier one of which corresponds with a division in mm. on a brass 
ruler 1 m. long (to be used along the y-axis), and the other with 
a division in 0,1 rz (= 4 mm.) on a rectangle also of brass for the 
asymptotes. Everything has been executed with the utmost care in the 
Factory of Scientific Instruments, P. J. Kipp and Sons, J. W. Garrar 
suce. Delft. 
On the plate we find a system of axes OXYZ, and the YOZ- 
plane is turned over to the left. Here the curves: 
rey Pe, y= Se and =De 
have been drawn. 
All the F-eurves and F-asymptotes bave been indicated by 
”? DE) B ” ” 1 EE) DE) 7) DE) ” oa 
” ” S EE) ” S EE) ” EE) ” EE) — 9 —— «+ —— 
” ” D ” ” D ” EE) »”» 2 ek —— nennen 
1) Cf. Dunz. l.c. 
*) This series was called third subordinate series by Saunpers before. Proc, 
Amer. Acad. 40, p. 439, 1904, 
