the Spectrum of Sodii 



511 



m. 



1000 



X= + /C 



(which is nearly the same 

 as n), by observation. 



1 



1000-0 



Not yet observed. 



2 



2500 



169-6878 



3 



m-r 



302-7762 



4 



62-5 



350-5193 



5 



400 



373-0703 



6 



27-7' 



385-5080 



7 



20-40816 



3931049 



8 



15-625 



388-0527 



The Table also gives the values of x (by observation) and 

 of z (by calculation) of the derived curve. If we pass a 

 parabola with its axis vertical through three of these points, 

 viz. through : — 



? 2 =250, ^=111-1^ ? 6 =27'7', 



* 2 = 169-6878, ^ = 302-7762, ^ = 385*5080, 

 we find, by the method of the last paragraph, that 

 log P = 3-774,0300, 

 a= 3337-4120, 

 5=1438-35. 

 Putting these values into equation (5) and computing the 

 values of n (i. e. os) for the other terms of the series, we find : — 



m. 



n calculated. 



k by observation 



(which is nearly the same 



as +ri). 



Difference. 



1 



-469-4 



Not yet observed. 



Unknown. 



2 



Used for determining the constants. 



o-oo 



3 



Used for determining the constants. 



o-oo 



4 



+350-767 



350-519 



+0-25 



5 



+373-239 



373070 



+0-17 



6 



Used for deter 



mining the constants. 



000 



7 



+ 392-945 



393-105 



-016 



8 



+397-776 



398053 



-0-28 



2M2 



