Voiv. 6, 1920 
PHYSICS: D. L. WEBSTER 
31 
but the third, and there it is covered at high voltages by the fourth order 
jSi. But belongs to L2, and even its strong third order line is gone at 
X^.^ = 0.945 A, while a line still appears at the position of 4 /3i and 3 /. 
This must be 3 /. It is definitely visible though somewhat fainter than 
.15 
I^ZO 12.30 12.40 12.50 12.6O /2.70 
Glancing Angle 
KIG. 3 
Reckoning the intensities by measurement of the vertical Hnes drawn to the peaks in 
the figure, the ratio of ai to is 1.11 at 17.85 kv. and 1.10 at 4.00. 
3 Ir ai. It is doubtful at 1.01 A, but the fact that it shows at 0.945 
places it in Li. 
This line shows strongly when X^/„ = 1.01 A, but not at all at 1.08, 
as one might expect from the ionization work previously reported, which 
placed it in L\. 
