[ BOYLE] TEMPERATURE AND VELOCITY OF GAS CURRENT 95 
substances, we should have the free volume between the thorium hydro- 
xide and the testing vessel a constant ; or, in other words, the volume of 
the conducting tubes plus the intersticial volume of the absorbing sub- 
stance should be constant in all cases. 
Asa test we have Fig. 5, tuble 2, which shows the effect of altering the 
volume of the conducting tubes. | is the experimental 7-¢ curve, taken to a 
point just beyond the maximum current, in the case of the emanation con- 
ducted through tubes as short as possible to the testing vessel. II is 
the curve when an additional empty tube is inserted between the thorium 
tube and the testing vessel. ‘The extra volume diminished the values 
of the ionization currents, but was not sufficient to appreciably displace 
the maximum ordinate to the right along the g-axis. III is the curve 
when a tube containing a non-absorbing material, brick, replaces the 
empty tube of the case before. The difference between the volume of 
the empty tube and the intersticial volume of the brick was not sufficient 
to cause much variation between curve III and curve II. All three 
curves meet at a speed somewhat greater than that required for maxi- 
mum ionization current, and thenceforward coincide. 
TABLE 2. 
EMANATION TO TESTING VESSEL. 




No Tube Intervening. Empty Tube intervening. | Brick Tube Intervening. 
Ionization Ionization Ionization 
to in RER Ro in Current, ;| Flow in Pacer ee 
ce/sec. | 5 436.5 x10 ce sec. | x 436.5x 10 BU eA SE TD 
for amps. for amps. for amps. 
Nat. Leak 8.84 Nat. Leak 6.85 Nat. Leak NT 
.02 12.1 .06 13.45 .06 18.3 
.07 25.5 .09 23.7 09 25.2 
19 70.4 .24 77.8 .16 50.5 
.28 105.7 .41 115.4 .34 101.7 
.54 151.1 .B2 130.5 .50 132.2 
.68 167.6 .76 158.8 AL 154 2 
1.02 178.5 .90 161.6 1.14 164.9 
1.29 URS OV ya) A tate suet PH EE ee ER tI a ea UR Tt By 
1.60 168.7 1.44 165.3 1.40 160.8 
1.77 165.3 2.04 153.3 1.70 153.8 
2.22 146 4 2.43 139.6 1.98 147.6 
Nat. Leak 10.6 Nat. Leak 8.84 Nat. Leak 7.39 








