1895.] Electrification of Air, $c., by bubbling through Water. 337 



4. In continuation of these experiments, on the 25th of Septem- 

 ber the arrangement represented in fig. 2 was set up. An outer 



FIG. 2. 



metallic guard-vessel, M, was kept connected by a wire to the case and 

 to one pair of quadrants of a quadrant electrometer, E. Water in an 

 inner glass or metal jar, A, was connected by a platinum wire to the 

 other pair of quadrants of the electrometer. To have this inner jar 

 well insulated, it was supported on a block of paraffin ; and the upper 

 end of a glass tube dipping into the water was fitted into one end of 

 a tube of paraffin, to the other end of which was fitted a tube for 

 ingress of air, from bellows, as shown in the figure. The insulation 

 of this arrangement was found to be good. When air was blown 

 through the water it was found that the jar containing the water 

 became positively electrified. 



5. To prevent splashing of water oat of the jar, a paper cover 

 was put on its mouth, or the jar was tilted, as shown in fig. 3, 



FIG. 3. 



so that the bubbles broke against the inside of the jar. In three 

 experiments thus made, the same electrification was still found, 

 amounting to about 6 volts positive in a quarter of an hour. 



6. As the jar was in every experiment positively electrified, the 



