54 Mr. J. S. Ames on some Gaseous Spectra. 



lines rapidly growing fainter towards the ultra-violet end. 

 If the lines which are marked with letters in my list are 

 actually these same lines, and if Cornu's measurements apply 

 to them also, we have the following measurements for the 

 series : — 



Ames. Cornu. Huggins. 



C 6563-04 







F 4861-49 







G' 4340-66 



4339-5 





h 4101-85 



41010 



4101-0 



H 397025 



3968-9 



3968-9 



a 3889-15 



3887-8 



3887-5 



(3 3835-6 



3834-5 



3834-0 



y 37980 



3796-9 



3795-0 



8 3770-7 



37694 



3767-5 



e 3750-15 



3749-3 



3745-0 



K 3734-15 



3733-6 



3730-0 



n 3721-8 



3720-6 



3717*5 



3711-9 



3710-7 



3707-5 



t 







3699-0 



Of course my scale is different from Cornu's ; but it seems 

 remarkable that the measurements of Cornu and Huggins 

 should vary so much, as they used the same standards. I 

 have marked 7 (3798*0) nebulous ; but besides this back- 

 ground there is a sharp line there, which undoubtedly belongs 

 to the secondary spectrum. It is strange, too, that the first 

 four lines of the series should coincide with solar lines, while 

 none of the others do. There are, however, on Rowland's 

 map certain hazy places which are approximately where the 

 most nebulous hydrogen -lines fall ; but there are no lines 

 corresponding to H, a, and |3, which are strong and clear on 

 my photographs. 



Knowing that Banner's formula applied most exactly to 

 the visible hydrogen -lines, I calculated the constant and used 

 it to foretell lines. Indeed it was in this way that I selected 

 the last three of the lines in the series, There was never any 

 ambiguity in the selection. These lines were the only nebu- 

 lous ones in the spectrum ; but they were so faint as sometimes 

 to escape notice until looked for. 



Correcting my wave-lengths for atmospheric refraction as 

 best I could, I found that the constant in Balmer's formula 

 should be 3647*20. Making the calculations, then, with this 

 constant, and comparing the deduced wave-lengths with mine 

 (corrected) we have : — 



