424 Proceedings of Royal Society of Edinburgh. [sess. 
We also measured tlie leakage at different voltages with the zinc 
cylinder in the glass bulb described in § 30, charged to a definite 
potential, and the uranium connected to the insulated terminal of 
the electrometer. The voltages up to 90 volts were obtained by 
connecting one terminal of a battery to the zinc, and keeping it 
connected during the experiments, while the other terminal was 
connected to sheaths. For higher voltages the zinc was charged 
to the given potential, and then disconnected from the charging 
body. 
Voltage per 
2 mms. 
Leakage per minute 
in scale divisions. 
2 
4 
22 
92 
100 
120 
92 
132 
200 
300 
415 
129 
138 
130 
137 
136 
[Sensibility of electrometer 140 sc. div. per min.] 
The appended' curves (diagram 9) were drawn by taking the 
leakage per minute as ordinate, the voltage as abscissa. Curve a 
80 60 90 120 150 ISO 210 
Diagram 9. 
gives the results obtained with the two Leydens arrangement 
reduced to voltages per 2 mms. between the internal and external 
