﻿12 Dr. W. M. Watts on the Spectra of Carbon. 



tion ; and by the use of more delicate instruments than have 

 yet been employed for this purpose, discoveries may be made 

 which will throw new light upon the subject of spectrum- 

 analysis. 



II. On the Spectra of Carbon. Bij W. Marshall Watts, 

 D.Sc, Physical- Science Master in the Manchester Grammar- 

 School*. 



IN the Philosophical Magazine for October 1869 I described 

 and figured a spectrum of carbon, which, so far as I know, 

 had not been previously observed, viz. the spectrum obtained 

 when the spark from an induction-coil is taken in carbonic an- 

 hydride or carbonic oxide, and a Ley den jar is included in the 

 circuit. I have recently had the opportunity of mapping the spec- 

 trum with a three-prism spectroscope of Browning's. 



I have converted the angular readings into wave-lengths by 

 means of an interpolation-curve carefully drawn from exact ob- 

 servation of twenty lines, whose wave-lengths are given in Ang- 

 strom's map. 



The brightest groups of lines are denoted by the Greek letters ; 

 and the reading of each line is given on the same scale to which 

 the diagram of my paper already referred to is drawn. The 

 wave-lengths are given in ten-millionths of a millimetre. 



Carbon-spectrum No. 4. 



f34 Wave-length 6578 

 a \34*5 „ 6562 Coincident with hydrogen «. 



43 „ 6165 



44-5 ,, 6095 



Two not very bright lines, each triple. 

 48 Wave-length 5954 Double. 

 j. T5895 



v » \5889 



51 „ 5855 Double. 



Three faint lines, the first double. 

 o f?>6 Wave-length 5688 



* V 



56-5 



a 



5652 





57-2 



a 



5640 





57*5 



>t 



5635 



Double. 



62-7 



a 



5426 



Double, 



66 



n 



5385 



Triple. 



69 



>} 



5306 





Communicated by the Author. 



