188 MR. E. C. C. BALY ON THE SPECTRA OF NEON, KRYPTON AND XENON. 
have not been measured before; the remainder must he deleted from Kayser s and 
Eder and Valenta’s lists. 
Out of the 16 lines in Table II., three apparently belong to the second krypton 
spectrum, but the origin of the others could not be traced; they undoubtedly are 
present in unfractionated argon, and are I’emoved by fractionation. It is curious tnat 
only three of the weakest krypton lines should be visible in the argon spectra ; a 
careful search was made for the stronger lines, but no trace ol them could be detected. 
The first or red spectra of the two samples of argon were similarly investigated, 
but no difference whatever could lie found, nor were any new lines observed beyond 
those already known. 
Table I.—Additional Lines Measured in the Blue Spectrum of Argon. 
Wave-length. 
Intensity. ! 
Wave-length. 
Intensity, j 
■i 
4537-82 
3 
4198-40 
2 
4510-07 
1 
4169-08 
1 
4445 - 92 
1 i 
. 4130-68 
1 
4440-40 
1 
4127-56 
1 
4405-06 
1 
4127-22 
1 
4385-16 
2 
4116-50 
o 
4338-40 
1 ; 
4031-50 
1 
4217-50 
1 ; 
Table II.—Lines to be Omitted from the Blue Spectrum of Argon. 
Wave-length. 
Intensity. 
4488-14 
0 
4443-545 
1 
4408-095 
1 
4343-904 
1 
4229-015 
1 
4199-97 
1 
4183-106 
0 
-- 
4146-761 
1 
Wave-length. 
Intensity. 
4098-33 
1 
4089-041 
1 
4065-171 
1 
4047-38 
1 
4023-730 
3 
4017-986 
1 
4010-052 
1 
3960-591 
0 
A further interesting fact in connection with the second spectra of krypton and 
xenon, is to be found in the existence of a number of lines of weak intensity common 
to the two spectra. Since these lines are equally weak in lioth spectra, it is impossible 
to say whether they in reality belong to krypton or xenon, and I have therefore 
credited them to both. On the other hand it may he that they are due to some 
common impurity, possiblv a still heavier element of the same family ; the e^ idence 
