GASEOUS SPECTRA IN VACUUM TUBES, 125 
HYDROGEN. EnNp-on TuBE. August 23, 1879. 
=a i, 
Colour. Subject of Observation. | Intensity. ape W.N. Place. Impurities. eee Pay are 
Part 1. 
Crimson- Sharp line, ; : : 0°3 | 32 616 Oxygen | 
Het Hazy band, . ors : . | 0-2 HH i oy Nitrogen | 
Faint haze begins, E ; : OL | 35 602 Carbon 
Red. Line in haze, , ; 0°3 aks. 36 230 Oxygen 
Haze band, 0°3 HH 37 090 Carbon 
Haze band, 0°3 37 736 Carbon 
Red Hydrogen, excessively bright,. | 10 fa 38 707 | 88 707 38 707 
Scarlet-Red. 38 707 
Part 2. 
Red Hydrogen ees 10 ‘Ei 38 707 
Broad haze band, . : il i 39 000 
Line in the haze, . 4 : Fr lee | 39 314 Oxygen 
< Second line, . 15 | 39 466 39 466 
Light-Red. Haze intervenes, il 3: 
Line, : 15 | 39 666 39 666 
Haze intervenes, 07 i 
Line, : 1°5 | 39 885 39 885 
Broa line, 3 ] 40 114 40 114 
Narrow line, . 1 I 40 286 40 286 
Broad and hazy line, 2°5 Li 40 489 40- 489 
zs 40 666 
Broadest line yet, , 3 | } 40 822 40 744 
Very black space intervenes, 
line, . * . 2°5 | 40 968 40 968 
A fainter line, : | a5 | 41 120 41 120 
Brightest line yet, 4 | 41 225 Oxygen 
; ; 41 354 41 354 
Double line, , , ne) \| 41 510 | 41 510 
Orange. Very black space intervenes. | 
; 2 41 704 
eae Vip ES Sa sp: 2] 41 812 Carbon, &e. 41 812 
’ ? 2 42 010 
Broadest cwm brightest line yet, 4°5 | } a ae 42 135 
Thin line, : 1 | 42 302 
42 401 
Band of closely packed thin ante 2 hl 42, 609 
Close double line, . 2 | 42 810 42 810 
— Single line, : ul | 42 950 
Very dark space inter venes, 
Strong line, . : j ; ; 3 1 43 148 
Part 8, 43 150 43 150 
Yellow line of last part, 3 1 43 151 
pailow. Faint double or treble line, 15 1 43 310 3 
Faint double, . 1 ' 43 430 : 
Thin but sharp and strong line, 2 | 43 545 43 544 
Brightest line yet in this part, 4 | 43 698 43 698 
Band of infinitely fine lines, with 1 l Fe Hes 
a stronger near the middle, itn 44 000 
Strong line, . : 2°5 I 44 112 44 112 
Very lack space intervenes, 
Hard band or thick line, ; : 3°5 I a Hee 44 294 44 294 
Citron, Very thin line, , ; : F 0°5 | 44 455 
Thin bright line, . ‘ 2 | 44 547 || 44 547 
Haze of fainter lines intervenes, | 
Thin bright line, . ; 2 | 44 6938 44 693 
Haze of fainter lines intervenes. 
Thin bright line, . F 1 I 44 900 
me An Ee fainter intervening line- Orel ee 45 130 
Now begins a Citron-green region with background of light resolvable haze more evenly distributed than 
before, so that there is no more of the very black interspaces ‘previously noted. 
