August 29, 1895] 



NATURE 



429 



Wave- 

 length. Intensity. 



4559-4 2 \'oung gives a chromospheric line at 4558'9. 



4544'I 5 



4520'9 3 A faint blue line, seen in " Uraninite, R." 

 Lockyer gives a line at 4522, seen in the gas 

 from some minerals. Young gives a chromo- 

 .splieric line at 4522-9. It is absent in the gas 

 from Broggerite. 



451 1 '4 5 A blue line, seen in " Uraninite, R," but not in 

 the others. It is coincident with the strong 

 head of a carbon band in the COj and Cy 

 spectnmi. 



4497'8 2 There is a hydrogen line at 449875. 



4471 '5 10 A very strong blue line, having a fainter line on 

 each side, forming a close triplet. It is a 

 prominent line in all the samples of gas 

 examined. Young gives the wave-length 

 447 1 '8 for a line in the chromosphere, and 

 Lockyer gives 4471 for a line in gas from 

 Brtiggerite. 



44357 9 Seen in " Helium I'uriss." 



44J7'i I Young gives a chromospheric line at 4437 "2. 



These two lines form a close pair. I can only 



■>8'f rn I '""^^ them in " Uraninite, R." No trace of 



~^ ' them can be seen in the gases from other 



■^"■^ i sources. Young gives chromospheric lines at 



!^ 4426 '6 and 4425*6. 



4399"0 10 A strong line, only seen in " Uraninite, R." 

 -Ybsent in the gas from the other sources. 

 Lockyer gives a line at 439S in gas from 

 certain minerals. Young gives a chromo- 

 spheric line at 439S"9. 



4386*3 6 Seen in all the samples of gas. \'oung gives a 

 chromospheric line at 4385 "4. 



4378*8 8 /These tw-o lines form a pair seen in " Uraninite, 



4371.0 8 ^ R," but entirely absent in the others. 



4348*4 10 Seen in " Uraninite, R." Lockyer finds a line 

 at 4347 in the gas from certain minerals. 



4333 '9 '° Probably a very close double line. Seen in 

 " Uraninite, R," and " Cleveite, R." Not seen 

 in the other .samples. Lockyer gives a line in 

 the gas from certain minerals at 4338. 



4^98*7 6 Only seen in " Uraninite, R." Young gives a 

 chromospheric line at 4298*5. 



42Si*3 5 Only seen in " Uraninite, R." 



4271*0 5 (Jnly seen in " Uraninite, R." Thestronghead 

 of a nitrogen band occurs close to this line. 



4258*8 7 Seen in all the samples of gas. 



4227*1 5 Only seen in ''Uraninite, R.' Young gives a 

 chromosplieric line at 4226*89 



aiqS*6 o I^*^^^^ three lines form a prominent group in 



^iSn*n n ' '" Uraninite, R," they are very faint in 



4181*5 9 1 " Cleveite, R," and in Broggerite, L," but 



4178*1 



are not seen in " Broggerite, R.'' 



I \n extremely faint line. Lockyer gives a line 

 at 4177, seen in the gas from certain minerals, 

 and \'oung gives a chromospheric line at 



4I79'5* 

 4169*4 6 Seen in " Helium Puriss." 

 4157*6 8 A strong line in " Uraninite, R," very faint in 



"Broggerite, R," and " L," not seen in 



" Cleveite, R." 

 4>43'9 7 Strong in " Cleveite, R," in " Helium Puriss.," 



and in "Broggerite, L." It is faint in 



" Uraninite, R," and not seen in "Broggerite, 



R." Lockyer gives a line at 4145 in gas from 



certain minerals. 

 4121*3 7 Present in all the gases except " Cleveite, R." 

 40443 9 Present in " Uraninite, R," and "Cleveite, R.'' 



.Ybscnt in the others. 

 j' These lines form a very close pair, seen in all 

 4026*1 10 J the samples of gas, except " Broggerite, R." 

 4024*15 6 I Lockyer finds a line in Broggerite gas at 



I 4026*5. 

 4012*9 7 Seen in all the samples of gas. 

 4009 2 7 Seen in " Helium Puriss." 

 3964*8 10 The centre line of a dense triplet. Only seen 



in " Cleveite, R," in Helium Puriss.," and 



" Broggerite, L." Hale gives a chromospheric 



line at 3964. 



NO. 1348, VOL, 52] 



Wave- 

 length. Intensity. 



3962*3 4 Seen in all the samples of gas. 

 3948*2 10 Very strong in " Uraninite, R," very faint in 



" Cleveite, R," and not seen in the others. 



Lockyer finds a line in gas from Broggerite at 



3947. There is an eclipse line at the same 



wave-length. 

 3925*8 2 Seen in " Helium Puriss." 

 3917*0 2 Seen in " Helium Puri.ss." 

 39132 4 Only seen in "Uraninite, R," and "Helium 



Puriss." Hale gives a chromospheric line at 



39 '3 S- 



,' A very strong triplet, seen m all the samples 

 38905 9 \ of gas. Lockyer finds a line having a wave- 

 3888*5 10 length 3889 in gas from Broggerite. Hale 



38859 9 ' gives a chromospheric line at 3888*73. There 



is a strong hydrogen line at 3889*15 

 3874*6 6 Only seen in " Uraninite, R." 

 3867*7 8 Seen in " Helium Puriss." 

 3819*4 10 Seen in all the samples of gas. Deslandres 



gives a chromospheric line at 3819*8. 

 38006 4 Seen in " Helium Puriss." 

 3732'5 5 Seen in "Helium Puriss." Hale gives a 



chromospheric line at 3733*3 

 37054 6 Seen in all the samples of gas. Deslandres 



gives a chromospheric line at 3705*9. 

 36420 8 Only seen in " Uraninite, R." 

 3633'3 S Seen in " Helium Puriss." 

 3627*8 5 Only seen in " Uraninite, R." 

 3613*7 9 Seen in " Helium Puriss." 

 3587*0 5 Seen in " Helium Puriss." 

 3447*8 8 .Seen in "Helium Puriss." 

 3353'S 5 Seen in " Helium Puriss." 

 3247*5 2 .Seen in " Helium Puriss." 



3187*3 10 The centre line of a close triplet. Very faint in 

 " Cleveite, R," and " Uraninite, R," and 

 strong in "Helium Puriss." and in "Brog- 

 gerite, L." It is not seen in " Broggerite, R." 

 2944*9 8 A prominent line, only seen in " Helium 



Puriss." and in " Broggerite, L." 

 2536*5 8 Seen in " Helium Puriss." .\ mercury Une 



occurs at 2536*72. 

 2479*1 4 Seen in "Helium Puriss." 

 2446*4 2 Seen in " Helium Puriss." 

 2419*8 2 Seen in " Helium Puriss." 



Some of the more refrangible lines may possibly be due to the 

 presence of a carbon compound with the helium. To photo- 

 graph them, a long exposure, extending over several hours, is 

 necessary. The quartz window has to be cemented to the glass 

 with an organic cement, and the long-continued action of the 

 powerfiU induction current on the organic matter decomposes 

 it, and fills the more refrangible end of the spectrum with lines 

 and bands in which some of the flutings of hydrocarbon, 

 cyanogen, and carbonic anhydride are to be distinguished. 



There is a great difference in the relative intensities of the 

 same lines in the gas from different minerals. Besides the case 

 mentioned by Prof. Kayser of the yellow and green lines, 5876 

 and 5016, which vary in strength to such a degree as to render 

 it highly prolable that they represent two different elements, I 

 have found many similar cases of lines which are relatively faint 

 or absent in gas from one source and strong in that from another 

 source. 



Noticing only the strongest lines, which I have called 



" Intensity 10," " 9," or " 8," and taking no account of them 



when present in traces in other minerals, the following appear 



to be special to the gas from uraninite : — 



4735' I 



4658-5 



4428*1 



4424*0 



4399 •(> 

 4378*8 

 437 1'O 

 4348 '4 

 4198*6 

 4189*9 

 4iSi*5 

 4157-6 

 3948*2 

 3642*0 



