ELECTRIFICATION OF AIR, VAPOUR OF WATER, AND OTHER GASES. 219 



Without the candle, 195 divisions negative for 60 strokes were noted. 

 With the candle inserted when about to withdraw the electrified air to the filter, 

 the deflection was, for 40 strokes, 81 divisions. 



Best Charging Potential for Air and for Carbonic Acid Gas, in a Cylinder of 

 Metal, 48 centims. long and 21 centims. diameter. Greatest Electric Density 

 Obtained, and Loss of the Electrification. 



73. Numerous experiments were made to find the charging potential which 

 would give the greatest electric density to air drawn off from a metallic can, A, 

 fig. 10. An insulated needle-point, B, was fixed by a paraffin stopper in the bottom 



Fig. 10. 

 Ga/tzf Serfc// surrwtndtna ffl(croffifer. 





of the can, and was connected with the insulated terminal of a Voss electric 

 machine, C, and of a vertical electrostatic voltmeter, D. A pipe passed from 

 aperture No. 5 in the top of the can tcx a standard electric filter, E, insulated on 



2 F 2 



