MR. E. C. C. BALY ON THE SPECTRA OF NEON, KRYPTON AND XENON. 189 
of the periodic table of elements is against this, but of course such evidence cannot 
be considered to be conclusive, and we may perhaps look forward to the discovery 
of such an element at a not very distant date. Experiments are at piesent being 
carried out in this direction. 
The wave-lengths of these lines are given in Table III., the values obtained in 
both gases being given. 
'Table III—Lines Common to the Second Spectra of Krypton and Xenon. 
XVaA^e-lengths. 
Intensity. 
Wave4engths. i 
Intensity. 
Ill krypton. 
In xenon. 
In krypton. 
In xenon. 
1 
5.562 • 45 
5562-46 
2 i 
j 2844-59 
2844-60 
3 
5143■25 
5143-24 
1 
* 2941-10 
2941-10 
1 1 
' 4857-36 
4857 - 37 
1 
! 2811-81 
2811-81 
3 
3942-28 
3942-29 
1 
2756-66 
2756 - 64 
1 
3768-10 
3768-08 
1 
2733-38 
2733-36 
4 
3765-98 
3765-99 
4 
2732-46 
2732-48 
1 
1 
(much \yeaker 
2696-71 
2696-73 
4 
i 
in krypton) 
2691-94 
2691-92 
1 
i 3751-81 
3751-80 
1 
2690-35 
2690-33 
1 
3564-38 
3564-40 
4 
2670-78 
2670-80 
0 
^ \ 
i 3428 - 95 
.3428 - 95 
1 
2648-80 
2648-79 
1 i 
' 3396-72 
3396-72 
2 
2624-63 
2624-65 
1 1 
! 3387 - 26 
3387-26 
1 
2616-80 
2616-79 
1 
' 3379-18 
3379-20 
2 
2581-84 
2581-84 
! 1 ! 
1 ^ i 
! 3.360-22 
3360-20 
2 
i 2572-44 
2572-46 
i I ! 
3315-80 
3315-80 
1 
2513-50 
2513-52 
1 ' 
' 3222-40 
3222-40 
1 
! 2494-10 
2494-11 
3 i 
3175-78 
3175-80 
3 
2468-56 
2468-54 
2 
3044 - 93 
3044-91 
1 2 
2425-15 
2425-18 
2960-92 
2960-93 
2 
i 
In addition to the above, there remains what is proljably only a chance coincidence 
at X = 4577'36 and X = 4577'40 in the xenon and krypton spectra respectively ; 
mention should also be made of the bright lines at X = 3330-90 and X = 3330-88 in 
the two spectra. 
As regards Liveing and Dewar’s values for the wave-lengths of these gases, it 
will be seen from the tables that there is in general a complete agreement in the 
fourth significant figure between the two sets of measurements. A great number ol 
lines which do not appear in Liveing and Dewar’s lists have lieen measured ; this is 
only to be expected from the fact that these observers m all probability were nou 
dealing with perfectly pure gases. The relative intensities of the lines are about tlie 
same in the two series of measurements, but of course the general average of 
intensity in Liveing and Dewar’s measurements is the weaker. Tliese observers 
