DR. W. M. HICKS; A CRITICAL STUDY OF SPECTRAL SERIES. 
443 
Argon. There are a large number of strong lines m the visible spectrum 
evidently connected with D(l) and F (2) lines. The oun is so small that the 
qualifying test for D lines is not so definite as in the other gases, although this is to 
some extent remedied by the fact that the measures on the whole are good with a 
possible maximum error of '02A. We shall therefore make no attempt to discuss the 
F and D series with the same fullness as in the other cases. The groups selected are 
certainly not the only ones and possibly may not be the most important ones, but 
they will be sufficient to give data for the determination of the oun to about the 
same degree of accuracy as for the other gases of this family. Take for the first 
group. 
m = 1. 
(1) 23782-51 (K.) 179'92 
7 lid 
(2) 23899-08 (K.) 
m = 2 
(3)39357-06 178*95 
17lfd 
(3)39420-68 
39id 
(5) 39439-33 
m = 3 
(6) 23962-43 (E.V.) (1) 44827-37) 175*51 (l) 45002-88 
39id 
(3) 44835-41 
(4)39536-01 
The lines for m = 2, S are by Eder and Valenta. Again the low intensity for 
Dji (1) is to be noticed, but we have here some indication of the source of this 
peculiarity. Eder and Valenta give the line at 23899-83 of intensity 9, and state 
that it appears only with a very strong condenser discharge. The difference in the 
two measures {dX = -13A) may possibly be due to observation although it is greater 
than is the rule between the measures of K. and of E.V. As an oun displacement in 
the sequent produces a change dn — A, the difference may be due to 2di displacement. 
If so, no error will be introduced in the succeeding considerations by overlooking this, 
treating it as due to observation error and using Kayser’s measurements, subject to 
a smaller possible error. For in either case the dependence of the sequent mantissa 
on the multiple law is not affected and although the multiple itself is different, at the 
same time the difference in the two readings will not modify the formula constants to 
an extent to appreciably affect the calculated lines for m>2. 
Using the limit I)(oo) = S(go) = 51731 *03 and the first two Du lines the formula 
found is 
n = 51731-03-N/jm + 989074- 
/I m \ 
