320 HENEY A. EOWLAND 



then to move the key K back and forth until R' was found that gave 

 the same deflection. D, Fig. 2, was now reversed and the process 

 repeated. This was repeated with different values of R and n and the 

 apparent capacity. This gave great variation of apparent capacity with 

 different values of R, which should not be the case, and, therefore, 

 gave a means of finding the resistance due to absorption or absorption 

 resistance, as we will designate, by approximation. As the effect of 

 absorption is a resistance it is possible to find what resistance, if added 

 to R, will make all the values of the capacity as determined for the 

 different values of R the same. Therefore it should be the same for 

 any two values of R. Calling the two values of R in the two cases 

 R % and J? 2 respectively and the two corresponding values of R', R^', and 

 R%, and let A be the added resistance due to absorption, the capacity 

 should be the same in the two cases, or 



+ r) - (#- 



A _ - 



From this A is found for the period used. By doing this for a 

 number of different values of R, the true value of A is approximated. 

 A was thus found for the condensers 2 and 3 microfarads with different 

 values of n. The calculations were again performed adding to the 

 different values of R a constant resistance A. The capacity that was 

 found when A is added to R is called the corrected capacity. In the 

 table below are collected the corrected values of the capacities together 

 with n and the resistance A. 



Capacity 4-94 4-96 4-96 4-64 microfarads. 



n 131-1 53-3 31-98 14- complete alternations. 



A '5-19 20-5 34-09 139-62 absorption resistance in ohms. 



The last value of the capacity seems 'to be an error, possibly one of 

 calculation. However, the results seem to show a nearly constant 

 capacity, but a resistance increasing rapidly with decrease of period, as 

 Maxwell's formula shows. The constant value of the capacity remains 

 to be explained. 



But in the above, determinations of absorption resistance are by 

 approximation. Professor Eowland has, therefore, devised a method 

 by which it can be measured directly. This method, with the results 

 that have been derived by it, will now be given. 



