G4 
FFtOFESSOE W. EAMSAY AND DR. M. W. TRAVERS 
teni])eratiire of li(|uid air by applying a slight pressure. The liquid was then allowed 
to evaporate hack into tlie gasholder in six successive fractions, which were stored in 
separate tuljes, Nos. 2 to 7. Fraction 2 was discarded, as the spectrum showed that 
hut little krypton was present. 
The remaining five fractions, Nos. 3 to 7, were submitted to a further fractionation 
in the following manner. The fraction containing the greatest quantity of argon (3) 
was introduced into the gasholder and condensed in tlie hidh. About two-thirds r)f 
this was then allowed to evaporate, and the gas transferred to a tube (8); tins gas 
was afterwards discarded. The contents of the next tube (4) were then condensed, 
along with tlie residue from 3, and again partially evaporated ; this gas formed the 
second fraction (9) of the next series. This process was repeated with each of the 
fractions from 3 to 7, the quantities of gas taken off at each fractionation being so 
graduated that the six residting fractions (8 to 13) were approximately equal. The 
last fraction was taken off through the })ump, while the liquid air in the jacket was 
removed so as to make sure that no traces of xenon were lost. By treating the 
fractions 9 to 13 in the same way, six other fractions (14 to 19), were obtained; 
of these the first two (14 and 15) were rejected after spectroscopic examination. The 
numbers indicating the rejected fractions are enclosed in square lirackets. 
As the four remaining fractions (16 to 19) solidified at the temperature of litpiid 
air, we thought that hy mixing the gases with oxygen it might perhaps be possible 
to obtain a more rapid and complete separation. A single experiment sufficed to 
convince us that the gain would have to he consideralile to compensate for the 
additional trouble and difficidty in manipulation; the method was therefore 
abandoned. 
[2] 
-[8] 
-L14] 
3 
9 - 
[15] 
4 
10 
16 — 
5 
— 
11 
— 
17 
6 
12 
18 
7 - 
- 13 - 
- 19 
r[-0] 
21 
p24 (D = .32-07) 
25 (lost) 
p27-n 
0(3 
■ 28- 
L-29 
(D = 
47-55) 
56-04) 
Proceeding hy the original method, fraction 16 was condensed, and evaporated in 
two portions, 20 and 21. The lightest portion (20) amounting h-* two-thirds of 
the wliole was discarded; the heavier (21) was liquefied together with fraction 17, 
and divided into a light ])ortion (22), amounting to about one-fifth of the volume 
of the mixed gases, and a lieavier portion (23). In the same way, fractions 24, 
25, and 26 were obtained from fractions 18 and 23 ; and fractions 27, 28, and 29, 
from fractions 19 and 26. 
In the early stages of the fractionation the spectroscope had been the sole guide in 
