Chemical and Physical Papers. 65 



given as very faint. We have measured optically about sixty- 

 five of these lines, including all but the very faintest. The 

 measurements, with one exception, agree with Baly's to within 

 one angstrom. In this case it is quite evident that there is a 

 misprint in Baly's table, for our measurement agrees well with 

 that given by Living and Dewar (Proc. Roy. Soc. 67, 467, 

 1901) for this line, while it differs from Baly's by much more 

 than the limit of error. 



Besides the lines of neon, the tubes show about fifteen fairly 

 strong lines which do not seem to belong to hydrogen, helium, 

 or any of the familiar gases. These lines are given in a list 

 of lines shown by the more volatile gases of the atmosphere 

 and by the gases from Bath Springs as published by Living 

 and Dewar (loc. cit.). This would seem to show that the 

 lines are not accidental and that it is legitimate to look for a 

 new very volatile gas in this residue. 



The argon was identified from its spectrum by measure- 

 ment of wave-lengths and by direct comparison of the spec- 

 trum with that given by a known specimen of argon. 



-5 



