308 Profs. J. A. Fleming and J. Dewar, On the 



At the last observation, 10,000 ohms taken out of galvanometer- 

 circuit increased the galvanometer deflection by 2 mm., showing that 

 conductivity had begun. 



Dielectric Constant of Ammonium Hydrate. 



(Ordinary laboratory solution 0*88 sp. gr.) 



Frequency of contact maker 120. Galvanometer deflection with air 

 as dielectric = 2*43 cm. for 100 volts. 



Temperature Galvanometer 

 in platinum deflection Dielectric 



degrees. in centimetres. constant. Observations. 



-184-2 12 35 4-82 Charging volts 101. 



-171-8 12-92 5-06 



-154-8 8-70 17-80 Charging volts 20. 



-143-5 3-45 98-80 



The curves for the sodium chloride 10 per cent, solution and 

 0*880 ammonia are given in fig. 3. 



Dielectric Constant of Ammonium Hydrate. 

 (Dilute solution l/100th gram molecule per litre.) 

 Galvanometer deflection with air as dielectric = 2*60 cm. for 100 volts. 



Temperature Galvanometer 

 in platinum deflection Dielectric 



degrees. in centimetres. constant. Observations. 



-198-0 6-97 2-47 Charging volts 100'8. 



-198-1 6-97 2-47 



-169-5 7-00 2-48 



-148-2 9-85 3-78. 



It will be seen that the dielectric constant of the strong solution 

 of ammonium hydrate increases much faster than that of the very 

 dilute solution with rise in temperature. 



Hence it was considered desirable to obtain an approximation to 

 their resistances. 



Ammonium Hydrate, sp. gr. = 0*880. 

 Electrical resistance of condenser. 

 Temperature 



in platinum Kesistance of condenser 



degrees. in megohms. 



— 180 " greater than 10,000*0 

 -149 about 2800 

 —137 about 17*0 



— 128 about 0*8 



