408 Profs. G. D. Liveing and J. Dewar. [Mar. 9, 



Table of Carbon Lines. 



Authors. 



Angstrom and Thalen. . . < 



Coloi 



Wave-length. 



6583 

 6577 

 5694 

 5660 

 5646 

 5638 

 5379 

 5150 

 5144 

 5133 

 4266 



Liveing and Dewar 



Ultra- 

 violet . . ' 



3919 

 3876 

 2995 

 2968 

 2837 

 2836 

 2746 

 2733 

 2640 

 2541 

 2528 

 2523 

 2518 

 2515 

 2514 

 2511 

 2509 

 2506 

 2478 

 2296 



Intensity. 



2 

 1 



4 

 4 

 3 

 5 

 6 

 4 

 3 

 5 



diffuse 



2, diffuse 

 4, „ 



4, very diffuse 



5, „ „ 



2 

 2 



3, very diffuse 



Spectrum of Incandescent Carbon Filaments. 



We have also examined the spectrum of Swan's incandescent lamps. 

 So long as the carbon thread is unbroken, it emits a continuous 

 spectrum, on which neither bright nor dark lines are visible. By 

 gradually increasing the number of cells in the battery, until the 

 thread gave way, we found at the instant of fracture, for a small 

 fraction of a second only, that a set of flutings in the green appeared. 

 In some of those lamps we observed, when the current was nearly as 

 much as the carbon thread would bear without rupture, that a sort of 

 name appeared in the lamp. On examining the spectrum of this 

 flame, it gave the flutings of carbonic oxide very distinctly, and we 

 made sure that they were those of carbonic oxide, and not those of 

 hydrocarbons, by comparison with the bands of a Bunsen burner. 

 Closer examination showed that this flame was strongest about the 

 junction of the carbon thread with one of the conducting wires, and 



