given by Carbon and some of its Compounds. 123 



In connexion with these experiments of La Rosa may be 

 mentioned the observation which has frequently been made*, 

 that an ordinary carbon-filament incandescent lamp in which 

 the current is increased till the filament gives way shows a 

 flash of the " Swan " spectrum, due, no doubt, to the volati- 

 lization of carbon vapour at the moment of disruption. 



The following summary of wave-length measurements of 

 the chief lines of the band spectra of carbon and of some 

 of its compounds will be useful for reference. 





o 



Angstrom 

 & Tiialen. 



Hasselberg. 



Kayser & 

 Runge. 



Eder& 

 Valenta. 



Fowler. f 



6191-1 

 6121-8 

 60599 

 6005-1 



5958 2 



Red. 

 Group I. { 

 C tt . 



1 



Yellow-green. ( 

 Group II. j 



Cy. 1 



(Eder's /3.) 



Emerald-green. ] 

 Group III. J 



o*. 



(Eder's y.) { 



Blue. f 

 Group IV. 



CV 1 

 (Ederso.) [ 



6187-3 + 09? 

 6119 +0-9? 

 6056-3 + 10? 

 6000-8 + 10? 

 5953-5 + 10? 



56330 + 1-0? 

 5583-0+1-1? 

 55380 + 1-0? 

 55000+1-1? 

 54660 + 09? 



5164-0+0-9? 

 5128-0 + 0-8? 

 5097-7+0-8? 

 5082-4+0-8 '( 

 5079 2+0-8? 



6186-4+0-9 ? 

 6121-0+0 9? 

 6050-8 + 10? 

 59930+0-9? 

 5951-0 + 1-0? 



5636-4+10? 

 5585 1+1-1? 

 55375 + 10? 

 5500 6+11 ? 

 5471-6+0-9? 



5164-4+0-9? 

 5128-2+0-8? 

 5096-9+0-8? 





6188 

 6120 

 6052 

 5999 

 5955 



[5635-43] 

 [5585-50] 



[5540-86] 

 5501 

 5471 



[5165-30] 



[5129-36] 



5096 



5084 



4737-25 

 4715-37 

 -HUI7-66 

 4684-58 

 4680-25 











5635-43 



5585-50 

 5540-86 



Komp. 



(I. A.) 

 5635 o04 

 5585*493 

 5540-890 

 5501914 

 5572-670 



Lei nen. 

 5165473 

 5129579 







5165-30 

 512936 





4734-8+0 9? 

 47128+0-9? 

 46953+0-9? 

 4683-5+0-9 ? 

 4676-7+0 9? 



473718 

 4715-31 

 4697*57 



4684-94 



Hindrichs. 

 4737-147 

 4715-453 

 4697601 

 4683-491 

 4672-979 

 4666100 

 4662-848 



47360+0-9? 

 47140+09? 

 4697-0+0-9? 

 4682-0+09? 



These four groups are followed in the spectrum as given by 

 the Bunsen flame by a group Cf of complicated structure, 

 consisting of a band shaded by fine lines from about 4371 

 to 4335, separated by a fine detached line 4324 from a strong 

 edge at 4315, which forms the commencement of a shaded 

 field extending to 3873. The luminosity of this field falls off 

 from 4315 towards the violet, and then increases again to 



* Liveing and De-war, Proc. Roy. Soc. xxxiii. p. 403 (1882). 

 f ' Index of Spectra,' App. V. p! 67. 



