196 



ELECTRICAL RESISTANCE OF ACETIC ACID 



and a cylindrical condenser were made and their capacities 

 were determined as follows: 



If Ci, R] and Ro be known, Co may be 

 accurately measured, provided the condition ^ 



for sensitivity be adhered to. A known resis- 

 tance as great as 10*^ ohms was necessary for the 

 calibration of the smallest capacity. A sub- 

 divided megohm was not obtainable, so three 

 Hittorf resistances were constructed. This 

 type of resistance is non-polarizable and is 

 made by filling a glass tube, fitted with Cadmium 

 electrodes, with a 10% solution of cadmium 

 iodide in amyl alcohol. The tube was then 

 sealed off and placed in a larger test-tube filled \ — V 

 with oil. Leads were then soldered to the elect- p ^ 

 rodes and passed thru a cork, which closed the 

 tube, (see figure 41. 



The -J M. F. condenser was used as capacity Ci in the 

 network, thru-out the work. 



I Making C2 = .05 M. F. of a ''L and N" subdivided con- 

 denser, 



and Ri= 3000 ohms, 



R.2 was adjusted for a balance 



and C2 was obtained in terms of Ci. 

 TI Making C2 = .05 M. F. 



and Ro = No. 1 resistance, 



then Ri was adjusted for a balance, 



and No. I resistance was obtained. 



III Making C2 = Mica condenser No. I, 



and R2 = No. I resistance, 

 then Ri was adjusted, 

 and No. I capacity was obtained. 



IV Making C2 = No. I condenser, 



No. 2 resistance was determined in a similar way. 



V Making C2 = No. I condenser. 



No. 2 capacity was measured. 



1 Stewart and Gee, Pract. Physics, Vol. II, pp. 494. 



