DR. W. M. HICKS: A CRITICAL STUDY OF SPECTRAL SERIES. 



389 



large that there can be no doubt. These numbers are in analogy with the values 

 for Ca and Sr viz 13* and M, are in the usual ratio 5:3, and stand to the 

 observed values for BaD (3) given in Table II. in a similar relation to those in Sr 



. 



, oT } . mU8t ^ ' 3 (2)> "^ lf the general rale found above that ^e mantissa 

 of VD U (2) is a multiple of A, holds, it is possible to obtain a very accurate value As 



a fact, with F, (.) = 25906 the mantissa of F,() very nearly the multiple of 

 87 A, fit is made so exactly, taking A, = 11 960, then F,() becomes about 25922 

 This value, with the D satellite differences of 15*, 9*, give 



F,(oo) = 25922 



260-17 

 F 2 ( oo ) = 26182-17 



157-95 

 F 3 (oo) = 26340-12 



and it is seen how close the separations come to those observed. If we put 

 F, ( co) = 25922 + the mantissa of 



D 13 (2) = l-040539-387=87(H960-2--45) = 87A,. 



The D(2) lines calculated from these and D^oo) = 28610"G3 found above give the 

 following scheme in wave-lengths on ROWLAND'S scale in vacuo : 



The last one only comes within the region in which RANDALL'S ultra-red lines lie, 

 his longest wave-length being 29223, belonging to the doublet treated as a possible 

 D line above. If the rules employed are valid, these values can only err by a few 

 units. The denominator of VF n (2) is 2-923500-113'9f In the cases of Ca and 

 Sr there is apparent the existence of satellites, viz., F w (2) = F,,(2) ( 3*) and 

 Fi 3 (2) = F n (2)( 5$), and in both cases the mantissa of one of the F, (2) sets thus 

 found are multiples of A.? If this is general the mantissa for BaF,., (2) will be 

 920085-113-9^. This is 77 (I1949'l-r48), sufficiently near to give some weight 

 to the allocation. If = -10 this is 77 x 1 1963*9 and the value for D 13 given above 

 becomes 87 x 11 964 "7, giving a value of A 2 = 11964 within limits of error A, = 11964 

 makes the oun 683'66 = 3Gl'98^ with W = 137'43. The F satellites thus constituted 

 would, if existing, have separations for m = 2 of 18 "02 and 12 "03, and for m = 3 of 



