196 



ELECTRICAL RESISTANCE OF ACETIC ACID 



and a cylindrical condenser were made and their capacities 

 were determined as follows: 



If Ci, RI and R 2 be known, C 2 may be 

 accurately measured, provided the condition , 



for sensitivity be adhered to. A known resis- 

 tance as great as 10 6 ohms was necessary for the 

 calibration of the smallest capacity. A sub- 

 divided megohm was not obtainable, so three 

 Hittorf 1 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 

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

 rodes and passed thru a cork, which closed the 

 tube, (see figure 4). 



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

 network, thru-out the work. 



I Making C 2 = .05 M. F. of a "L and N" subdivided con- 



denser, 

 and Ri= 3000 ohms, 



R 2 was adjusted for a balance 

 and C 2 was obtained in terms of Ci. 



II Making C 2 = .05 M. F. 



and R 2 EE No. 1 resistance, 

 then RI was adjusted for a balance, 

 and No. I resistance was obtained. 



III Making C 2 = Mica condenser No. I, 



and R 2 EE No. I resistance, 

 then Ri was adjusted, 

 and No. I capacity was obtained. 



IV Making C 2 EE No. I condenser, 



No. 2 resistance was determined in a similar way. 



V Making C 2 EE No. I condenser, 



No. 2 capacity was measured. 



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



