Constants of Metallic Oxides at Low Temperatures. 375 



XIII. Dielectric Constant of Oxide of Lead (PbO). 



(Suspended in water.) 



Corrected galvanometer deflection when the condenser had air as 

 dielectric = 4*04 for 100 volts. 



Mean 



Temperature galvanometer 

 in platinum deflection Dielectric 

 degrees. in centimetres, constant. Observations. 



— 197 '4: 4%56 78'5 Condenser charged to 1 "434! volts. 

 -184-8 5-23 90-0 



-159-2 5-40 93-0 

 -150-2 5-40 93-0 

 -128-3 5-40 93-0 



In contrast with the above results, we tried dissolving the oxide of 

 lead in caustic potash, and prepared a saturated solution of oxide of 

 lead (PbO), dissolved in a 5 per cent, solution of caustic potash. 



XIV. Dielectric Constant of Oxide of Lead (PbO). 



(Dissolved in a 5 per cent, solution of caustic potash.) 



Corrected galvanometer deflection w T ith air as dielectric = 3'03 cm. 



for 100 volts. 



Mean 



Temperature galvanometer 



in platinum deflection Dielectric 



degrees. in centimetres, constant. Observations. 



—189-2 7*47 171 Condenser charged to 1-434 volts. 



-170-2 7 45 171 



— 158-0 7-52 173 

 -148-4 7-60 175 

 -138-2 7-45 171 ? 

 -127-8 7-77 179 



Finally we tried bismuth oxide suspended in water, with the 

 results shown in Table XV. 



2 d 2 



