Wave-length. 
4471°5 
4435°7 
4437°1 
4428°] 
4424°0 
4399°0 
4386°'3 
4378°8 
4371°0 
4348°4 
4333°9 
4298°7 
4281°3 
4271-0 
4258°8 
42271 
4198°6 
4189°9 
4181°5 
4178°1 
4169°4 - 
4157°6 
4143°9 
W. Crookes—Spectrum of Helium. 305 
Intensity. 
10 A very strong blue line, having a fainter line on 
each side, forming a close triplet. It is a prom- 
inent line in all the samples of gas examined. 
Young gives the wave-length 4471°8 for a line 
in the chromosphere, and Lockyer gives 4471 
for a line in gas from broéggerite. 
9 Seen in “helium puriss.” 
1 Young gives a chromospheric line at 4437°2. 
( These two lines form a close pair. I can only 
_ see them in “uraninite, R.”’ No trace of them 
| 
a {+ can be seen in the gases from other sources. 
| Young gives chromospheric lines at 4426-6 and 
| 4425-6. 
10-_ A strong line, only seen in “uraninite, R.” 
Absent in the gas from the other sources. 
Lockyer gives a line at 4398 in gas from cer- 
tain minerals. Young gives a chromospheric 
line at 4398°9, 
6 Seen in all the samples of gas. Young gives a 
chromospheric line at 4385°4. 
These two lines form a pair seen in “uraninite, 
R,” but entirely absent in the others. 
Seen in “uraninite, R.” Lockyer finds a line at 
4347 in the gas from certain minerals. 
10 Probably a very close double line. Seen in 
“uraninite, R” and “cléveite, R.” Not seen 
in the other samples. Lockyer gives a line in 
the gas from certain minerals at 4338. 
6 Only seen in “uraninite, R.” Young gives a 
chromospheric line at 4298°5. 
5 Only seen in “uraninite, R.” 
5 Only seen in “uraninite, R.” The strong head 
of a nitrogen band occurs close to the line. 
i! Seen in all the samples of gas. 
5 Only seen in “uraninite, R.” Young gives a 
chromospheric line at 4226°89. 
(These three lines form a prominent group in 
| “yraninite, R,” they are very faint in ‘ clé- 
. veite, R,” and in ‘ bréggerite, L,” but are not 
| seen in ‘ broggerite, R.” . 
An extremely faint line. Lockyer gives a line 
at 4177, seen in the gas from certain minerals, 
and Young gives a chromospheric line at 4179°5, 
Seen in “helium puriss.” 
A strong line in “uraninite, R,” very faint in 
bréggerite, R,” and “1,” not seen in “‘clé- 
veite, R.” 
7 Strong in “cléveite, R,” in “helium puriss.,” 
and in “ bréggerite, L.” It is faint in “ urani- 
nite, R,” and not seen in “broggerite, R.” 
Lockyer gives a line at 4145 in gas from cer- 
tain minerals. 
me 6 UO SO 
ie oon) 
