88 
PHYSICS: DUANE AND PATTERSON 
Proc. N. a. S. 
new values bring Pt into line. For Bi, however, our correction is in the 
right sense but far too large. We cannot at present explain this dis- 
crepancy. Table III gives our new values for this relation. 
TABLE III 
ELEMENT Li-Li My {Lz- Li) - M /Ss - |8 
Pt .1706 .17158 —.0010 .0000 
Bi .2163 .20144 +.0149 +.0176 
The lines /Sy and 74 have been assigned by Coster to electrons which start 
from different outer orbits and fall, respectively, into L] and L3 orbits. 
Assuming the 74 electron to start from a higher orbit than 187, we should 
then expect 74 — (L3 — Li) to be greater than 187. Coster shows this 
to be the case except for Pt and Bi. Our new measurements bring both 
Pt and Bi into line with the other elements. Table IV contains values 
for these quantities in the cases of Pt and Bi. 
TABLE IV 
ELEMENT \i-{Lz~L\) 07 A 
Pt 847.8 844.9 +2.9 
Bi 980.6 (977.2) +3.4 
The value of for Bi was obtained, as suggested by Coster, by inter- 
polation based upon the constant difference in wave-length exhibited by 
the elements for ^2 — ^1, the wave-length for ^2 being known. The 
differences in the fourth column are in the same sense and of the same 
magnitude as those found by Coster for Ta, W, Au, Tl and Pb. More- 
over, if we estimate a value for the wave length of 74 for U based upon 
our value of L.3 for the same element, we obtain a difference greater than 
those above and also in the same sense. It is therefore quite well es- 
tablished that the jS? and 74 electrons start from orbits which maintain 
approximately the same difference in energy level as we go from Ta to U. 
The authors in 1920 compared the frequencies of certain L emission 
lines with the differences in frequency between corresponding L and M 
absorption limits.^ Kossel first pointed out that these quantities should 
be equal on Bohr's theory. At that time we found each L emission fre- 
quency to be equal to a corresponding difference in absorption frequencies 
within the limits of experimental error. Coster^'^ has recently extended 
this comparison with his new and more accurate measurements to in- 
TABLE V 
ELEMENT / Li — Mh rj L^ — Mb ai Li — Mi a> Li — Mt 
U 855.^ 855.1 1134.95 1131.8 1003.23 1002.17 990.37 989.21 
Th 819.19 818.8 955.78 954.80 944.08 943.15 
Bi — — 798.54 797.43 790.20 789.35 
/3i L-i—Mi /33 Lz—Ns fii Lz—Ma, 
U 1269.08 1265.87 1286.29 1285.78 1222.53 1220.86 
Th 1194.94 1193.15 1211.67 1209.77 1155.00 1151.86 
Bi 959.93 958.16 973.85 971.2 
