Titanium, and Vanadium by Thermelectronic Currents. 259 



Wave-lengths are given in international units and the 

 scale of intensities is that outlined in a former commu- 

 nication *. 



Some lines situated in the bright tails of the carbon bands 

 have probably escaped attention. The relative intensities in 

 arc and spark were obtained from the observations of Exner 

 and Haschek. A comparison of these results shows that the 

 red fringe spectrum of titanium is composed of the brighter 

 arc lines, and only one so-called enhanced line has been 

 recorded — namely, X 390053. As to the character and 

 origin of this spectrum very little can at present be said or 

 suggested, because the flame spectra of this element (chemical 

 and thermo-chemical excitation) are as yet practically un- 

 known. It is, however, of interest to mention that none of 

 these lines were observed by me in an ordinary arc between 

 electrodes made of the same kind of graphite ; but they ap- 

 peared near the cathode in heavy current arcs of from 20 to 

 #0 amperes. No trace of them was observed in the ordinary 

 condensed spark between graphite poles, but a few of the 

 brighter ones were detected in the self-induction spark. It 

 is therefore remarkable that they should constitute such an 

 important part of the red fringe spectrum. 









Vanadium. 









Relative intensities. 

 * 





Relative 



intensities. 



X. 



r 



Eed fringe. 



Arc. 



Spark. 



X. 



Red fringe. 



Arc. Spark. 



3902-25 







4 



2 



4128*10 



h 



10 10 



409268 



00 



15 



3 



4131-98 



JL 



10 10 



4099-80 



00 



20 



2 



413447 



000 



10 10 



4105-20 



00 



10 



4 



*4379 24 



1 



30 R 30 R 



4109-78 



000 



15 



10 



4384-73 



1 



30 30 R 



4111-80 



1_ 



30 R 



2 



4389-98 



6 



20 20 R 



4115-17 



00 



5R 



2 



*4408-50 



i 



10 15 R 



4116-50 



000 



15 



5 



4586-37 



00 



10 8 



4123-65 



000 



5 



3 



4594-09 



00 



10 10 



This spectrum is likewise composed of the brighter arc 

 lines only. It is of course possible and even probable, that 

 some lines have been overlooked, as in the case of titanium ; 

 this is, however, inevitable on account of the presence of a 

 strong continuous ground and of the carbon bands, which 

 fact, coupled with the relatively low dispersion of my 

 * Hemsalech, Phil. Mag. vol. xxxiii. p, 9 (1917). 

 S2 



