222 ME. J. ZELENY ON THE VELOCITY OF THE IONS 
Fig. 12. 
§ 10. Carbonic Acid. 
The gas used was taken from a cylinder of liquid carbonic acid. The small amount 
of impurities in this does not produce any marked change in the densit} T of the gas, 
and is assumed to be without noticeable effect upon the ionic velocities. As examples 
of the readings taken, the following two sets are given for carbonic acid gas saturated 
with aqueous vapour 
Temperature = 16’3° C. X = 3’02 centims. Barometer = 75'4 centims. 
Excess pressure in gasometer = ’44 centim. 
,, ,, ,, apparatus = - 21 ,, 
10 cells = 20’6 volts. 
Table XIII.—Moist Carbonic Acid. Negative Ions. 
«T5 
Voltage of outer 
cylinder. 
Electrometer deflection 
in 30 seconds. 
Descent of gasometer 
in 40 seconds. 
Cells. 
Divisions. 
Centims. 
- 6 
136 
2-34 
- 7 
106-5 
2-33 
- 8 
76 
2-33 
- 9 
41-5 
2.30 
- 10 
17-5 
2-33 
- 9-4 
28 
2-29 
- 8-4 
57 
2-28 
- 7-4 
91-5 
2-27 
Ionic Velocity in cms per sec. 
