the Echelon Spectroscope. 



397 



brighter, and cleanly split, each into two lines. Next we have 

 the outermost right-hand component of B, coincident with the 

 outermost left-hand component of C as in (2), fig. 8, with a 

 magnetic field of 21,800. 



With a still stronger field (23,800) the components of B 

 and C coincide with each other ; this is shown in (3) and also 

 in the photograph. In this way we are able to trace out the 

 gradual resolution of the original line. 



The line therefore becomes a sextet, the relative separation 

 of the components being shown below. 



H= strength of the magnetic field. 



8\ 1 is the difference in wave-length between the two inner 

 components of the sextet. 



8\ 2 is the mean difference in wave-length between the outer 

 components. 



8\ 3 is the difference in wave-length between the components 

 of the outer components of the sextet. 



<s\ 



JA, 



lyt 



a. 







X = 4358 10- 



10 metres. 







H. 



5,000 



^X r 



SVHxlO 6 . 



SK. 

 •143 



28-6 



fc.. 



£A 3 /Hxl0 6 



12,100 



•104 



8-5 



•341 



28-2 







12,900 



•112 



8-7 



•360 



28-0 



•052 



4-2 



20,000 



•166 



8-3 



•580 



29-0 



•098 



49? 



21,300 



•176 



8-3 



•60 



28-2 



•09 



4-2 



23,400 



•200 



8-6 



•68 



28-8 



•098 



4-2 



These values have also been confirmed by photographs taken 

 along the lines of force. As mio-ht have been expected from 

 theoretical considerations, the line first splits into a doublet, 

 and in a stronger field the doublet splits up into a quartet 

 exactly corresponding to the outer quartet of the line viewed 

 across the lines of force. 



The values obtained are given below: — 



H. 



$K 



3,550 



•098 



8,700 



•246 



L5,600 



•435 



£\ 2 /Hxl0 5 . 



27-8 

 28-4 



27-8 



d\. 



a 3 /Hxl0 3 . 



075 



4-8? 



