300 



Sir W. Crookes. 



[Aug. 1, 



Wave-lengths of the Eadium Lines according to the different 

 Authorities. 



Eunge. 



3649 -77 

 3814 -591 



4341 -0 



De- 



marcay 



3649 -6 

 3814-7 



4340 -6 

 4364-2 



4436-45 4436-1 

 4458 -0 



4533 -33 



4533-5 

 4600-3 



4627'4 

 4641 -9 



Exner w 



-j W 



TT ai \- i Crookes. 

 Haschek. 



2512 -46 



2709 -06 

 2736 -2 

 2813-60 2813-876 



2816 -25 

 2831 -98 



2877-10 

 2908 -0 

 2976 -17 

 3079 -97 

 3126 -53 



3541 -77 



3649-33 3649-712 

 3809 -393 

 3812 -170 



3814-62 3814-661 



3861 -77 



3961 -627 

 3993 -25 



! 4010 -397 

 4053-81 4053-124 



4340 -619 



Inten- ! 

 sity. ! 



Remarks. 



20 



30 



70 



10 



5 



100 



10 



10 



5 



I cannot see this line on my photo- 

 graphs. 



This is close to an iron line, 

 2709-14. 



I cannot see this line on my photo- 

 graphs. 



Comes between a fine pair of 

 platinum lines. 



Probably a platinum line, 2816'!. 



I cannot see this line on my photo- 

 graphs. 



Probably an iridium line, 2877'!. 



Probably a platinum line, 2908'!. 



Probably a platinum line, 2975'9. 



Probably a platinum line, 3079'8. 



I cannot see this line on my photo- 

 graphs. 



Ditto. 



A very strong radium line. 



A faint radium line. 



A faint radium line. 



The strongest line in the radium 

 spectrum. 



I cannot see this line on my photo- 

 graphs. Exner and Haschek 

 include it in their radium lines, 

 but in a note say it is not a line 

 of radium. 



A faint radium line. 



Probably a barium line, 3993'69. 



A faint radium line. 



A faint radium line. 



A faint radium line. 



1 cannot see this line on my photo- 

 graphs. 



Probably a platinum line, 4437'5. 



Demarc.ay says this is the centre 

 of a nebulous band, which be- 

 gins at 4463'7, has a maximum 

 from 4453-4 to 4455 2, and ends 

 at 4390-0. I cannot see this 

 on my photographs. 



I cannot see this line on my photo- 

 graphs. 



Demarsay says (with a query) that 

 this line does not belong to 

 radium. I cannot see it on my 

 photographs. 



Demar9ay says this is the centre 

 of a nebulous line, which be- 

 gins sharply at 462 1-9, has a 

 maximum at 4627'5, and ends 

 about 4631. I cannot see it 

 on my photographs. 



I cannot see this line on my photo- 

 graphs. 



