GASES BY THE ACTION OF RONTGEN RAYS AND OTHER AGENTS. 411 
Air in contact with Uranium Oxide. 
B = barometer reading = 759 millims. ; t — temperature = 13° C. ; tt — maximum 
vapour pressure at ^° C. = 11 millims. ; m = pressure required to sink plunger 
= 1 millim. 
Gauge reading (in millims.) — p. 
, B - TT + m 
V V — 
Result of expansion. 
^ 2/ 13 
B - TT - p 
147 
1-246 
0 
148 
1-249 
1 or 2 drops 
149 
1-251 
0 
150 
1-253 
1 or 2 drops 
154 
1-261 
Dense shower 
174 
1-305 
Fog 
196 
1-357 
Fog 
Least value of iq/vi with which condensation was observed = 1'249. 
This is identical with the number obtained when the uranium was contained in a 
glass bulb outside the expansion apparatus. (‘Camb. Phil. Soc. Proc.,’ loc. cit.) The 
number of drops is, as was to he expected, very much greater. 
Similar experiments were made with hydrogen. 
Hydrogen in contact with Uranium Oxide. 
B = barometer reading = 759 millims. ; t = temperature = 14'5° C.; v — maximum 
vapour pressure at C. = 12 millims. ; 7n = pressure recjuired to sink 
plunger = 1 millim. 
Gauge reading (in millims.) = 
1 B - TT + rii 
^■2^ = TS - r 
a — TT — ‘p 
Result of expansion. 
151 
1-255 
No drops 
153 
1-259 
1 or 2 drops 
161 
1-277 
Shower 
170 
1-296 
Dense shower 
198 
1-362 
Dense shower 
Least value of V 2 /V 1 with which condensation was observed = 1'259. 
Hydrogen exposed to Uranium Bays (through glass). 
B = barometer reading = 767 millims. ; t = temperature = 13° C. ; 77 = maximum 
vapour pressure at ^° C. = 11 millims. ; m = pressure required to sink 
plunger = 1 millim. 
Gauge reading (in millims.) = p. 
, B - TT + m 
p- 
B - TT - p 
Result. 
1.50 
1-246 
No drops 
153 
1-255 
Very few drops 
Least value of v^jvi with which condensation was observed = 1'255. 
3 G 2 
