THE STRUCTURE OF THE SERIES OF LINE- AND BAND-SPECTRA. 581 
instead of 0°75 without sensibly altering the differences of the last column. In all 
eases the agreement between the observed and computed wave-lengths and wave- 
frequencies is doubtless sufficiently close to justify the assertion that the RypBERG-THIELE 
formula represents the measurements most accurately. The same agreement is shown 
in the following calculations, which refer to some of the second bands. 
B Group. Second Band. First Series. B Group. Second Band. Second Series. 
log a; =0°90992,, dy = 6867-379 log a, = 0°57250,, vy = 14558°57 
log B, = 668740 — 10 log B, = 589220, — 10 
(m+ ») X obs. Acomp. | Obs. — Comp. (m + ») | v obs, v comp. | Obs. — Comp. 
125 6886-004 004 ‘000 1E0 14526°27 ‘27 00 
13°5 89183 181 + ‘002 12-0 14520°15 15 00 
14°5 92°614 605 + :009 13-0 14513°49 “50 - 01 
15°5 96°282 ‘277 + 005 14:0 14506:29 33 — 04 
165 ~| 6900°196 196 ‘000 15-0 1449865 "64 +01 
175 04°363 366 — 0038 16:0 14490°42 43 - 01 
18°5 08785 ‘784 + 001 17:0 14481:70 69 +°01 
19°5 13°449 “452 — 003 18-0 14472°45 ‘45 ‘00 
20°5 18°365 371 — 006 19-0 14462°72 ‘70 +02 
21°5 23°542 545 — 003 20°0 14452°43 ‘41 +02 
22°5 28-986 ‘970 +016 21:0 14441°67 63 + 04 
23°5 34°669 649 + °020 22-0 14430°37 *35 + 02 
24°5 40°584 584 ‘000 23:0 1441853 19) - 02 
255 46770 sero - 001 24:0 1440626 ‘26 ‘00 
a Group. Second Band. First Series. 
log a, = 0°88756,, dy = 627663 
log 8B, = 6°36303 — 10 
(m + p») X obs. AX comp. | Obs. — Comp. 
10:0 6289-60 "62 - 02 
11-0 6292-35 ‘36 - 01 
12-0 6295°36 37 -01 
13:0 6298-64 64 ‘00 
14:0 6302718 17 +01 
15-0 6306-00 5°98 + 02 
16-0 6310°06 05 +°01 
17-0 6314-40 “40 ‘00 
18-0 6319-02 01 +01 
19-0 632392 co +01 
20-0 6329°10 ‘08 +02 
21:0 6334-55 53 +02 
22°0 6340-28 25 + 03 
23°0 6346°27 "26 +01 
[have purposely computed wave-frequencies in some cases and wave-lengths in others 
in order to show that the RypBeRG-THIELE equation may be used in the same form in 
