'the Echelon Spectroscope* 401 



sake of uniformity the difference in wave-length between the 

 outer lines of the triplet is called h\ 2 - 



Jh; 



\ = 5768 10- 10 metres. 



H. 8\.,. 6A 2 /Hxl06. 



5,500 -182 33-2 



12,900 -441 34-0 



23,400 -768 33*1 



Along the lines of force. 



8,700 -294 33-9 



13,000 -434 33-4 



These measurements give a mean value 



= 10'0xl0- 13 . 



8X2 =33-4 xl0-e 



H 



\ 2 H 



where X, as before, is expressed in 10 ~ 10 metres. 



A similar series of measurements was made on the other 

 yellow (5790) line of mercury. This also splits into a pure 

 triplet, but the value of S\ 2 /fi is smaller than that obtained 

 with the other yellow (5768) line. The results of these 

 measurements are given below. 



cfA 



X=5790 10- 10 metres. 



H. 



5,500 

 12,900 

 22,300 



5X 2 . 

 •167 

 •405 

 •669 



SA 2 /HxlO G . 

 30-5 

 31-3 

 30-0 



Along the lines of force. 



8,700 

 13,000 



•409 



30-6 

 30-8 



