Gases contained in Small Vessels. 565 
partly) due to a radiation from the walls which is not of 
uniform type. On this supposition the term 6 would corre- 
spond to a very weak radiation, which is perfectly absorbed 
by as little as 3 cm. of air at 4 of an atmosphere pressure ; the 
coefficient b corresponds toa ‘more intense radiation of oreater 
penetrative power. ‘This radiation therefore ionises the gas 
proportionally to the pressure up to a pressure of about 
600 nm. 
The measurements are perhaps not accurate enough to lay 
much stress on this conclusion, or on the absolute “value of 
the constant 6 ; it is, however , quite certain that the leak in 
this case is not strictly proportional to the pressure, as will 
be seen from Table VI. In faci, the greatest possible error 
for the observations at 74 and 33 mm. respectively is less 
than the deviation in the ratio of leak by pressure. 
IIL. Observations with Nickel- Carbonyl. 
The same remarks as for air apply to the measurements 
with Ni(CO), at various pressures. It was, however, far 
easier to get consistent results in this case, as the leak is 
more than five times bigger than that in air at the same 
pressures, so that a whole series of observations could be 
executed in much shorter time, reducing the probability of 
changes in the ionization. 
Several series of observations were performed in both bulbs 
used for measuring the leak in air at different pressures. As 
these all agreed satisfactorily, only one series tor either vessel 
: will be quoied these are given in Tables VII. and VIII. and 
represented in figs. 1 and "2, 
TABLE VII. TaBLe VIII. 
Bulb I. Bulb II. 
‘Pressure Leak in Tea ae ap + b,, Pressure Leak in ie y=a,p+b,, 
in mm. |scale-divs. Pp =0:096, in mm. |scale-divs. =———..|ag=0°08, 
of mere. |per hour. ressure i =0:8: of mere. |per hour. Pressure |, 1-2. 
| of OL 
00700 200 13°9 00695 
209 14:7 
136 12-2 0 0897 150 12-6 0:0840 
72 78 0:1085 arg 116 101 00871 10°4 
46 51 01102 52 74 ei 0:0959 Td 
34 4°2 0:1285 4:0 50 a4 0:1080 52 
28 34 071214 3D 28 3°05 | 0:1088 
Li 271 0°1235 
