Manchester Memoirs, Vol. xlviii. (1904), No. 11. 



5 



steel, and iron had been rejected, polished aluminium was 

 finally adopted, as with pure mercury it was found possible 

 to use these contacts for several weeks together ; the 

 contacts now occurred with the greatest regularity, and 

 the position of the galvanometer spot could be read off to 

 a tenth of a millimetre on a scale one metre distant from 

 the galvanometer. 



The values obtained for the standard condensers at 

 our disposal were absolutely consistent, and some con- 

 densers used in the Electrical Engineering Department 

 of the Owens College were examined. The effect of the 

 high voltages to which they had been connected was 

 very noticeable. 



The following are a few typical results obtained : 



Condenser. 



Capacity. 



Equivalent 

 Resistance. 



Galva- 

 nometer 

 and Shunt. 



Capacity, 

 (determined) 



Siemens and 

 Halske, i Micro-< 

 farad. 



Mfd 

 •5 (.«) 



•5(^) 

 i*o 



ohms 

 15.770 



16,330 



7,600 



ohms 

 28 



28 



28 



Mfd 

 ■5129 



•4957 



I'OOI 



Siemens and 

 Halske, 5 Micro- 

 farad, which 

 was frequently - 



used on 

 alternating cur- 

 rent circuits. 



•5 

 i-o(a) 

 i-o (b) 



2-5 



2-5 + I'o {a) 



2-5 + I -o {b) 



17,000 

 8,300 

 8,590 

 3.275 

 2,340 

 2,360 



28 

 28 

 28 

 28 

 28 

 28 



•476 



•9709 



•9404 



2-453 

 3-422 



3*393 



