﻿for Measurement of Resistances and Capacities. 313 



results that in practice its satisfaction may be safely omitted. 

 Nonsatisfaciion of: the first (F large) is more serious, and 

 results in the incomplete balance failing to correspond with 

 the partial equality. The complete balance may, however, 

 always be arrived at by successive approximations Thus a 

 series of successive adjustments, first of R at &=}>, then of 

 P at S~ 0, then of R at 8 = }, again, will ultimately result in 

 the complete balance, however widely the theoretical con- 

 ditions are departed from. The rapidity of the measurement 

 may, however, be very much increased by paying attention 

 to the theory. When F is very small, the rate of approxima- 

 tion of the adjustments is initially rather slow, but it becomes 

 much more rapid as the complete balance is more nearly 

 reached. Xow in carrying out such a series it is in any 

 case desirable to diminish the sensitiveness of the galvano- 

 meter in the earlier stages. If we do this in such a way as 

 to at the same time partially satisfy the theoretical conditions 

 (/. e. by inserting a high resistance in series with the battery 

 in the arrangement of fig. 1 or with the galvanometer in 

 that of fig. o) the approximation becomes extremely rapid 

 throughout. This is shown by the results of experiments on 

 successive balances given below. 



Table II. 



S, 7650 a). K, -4314 mf. Q, 4000 co. H. .V mf. 



Arrangement of fig. 3. E.M.F. '2 volts. 



Arbitrary initial Resistance. -, , . A - • ,, -p , 



, ' ■ -Ji Commutator Variable Lai 



ance 



value of in series with " ........ 



1 , Lead t . adjusted. value. 



CT'\ \-;\ nmtiM Pr v 



resistance P. galvanometer 



(1) 3000 : -5Q 4 R 9900 



u p r>2uo 



.4 R 9900 



none II 1' 5176 I 



4- R 9908 I * 



u P 5176 J 



(2) 3000 -1 o i R 9600 



6 P r;090 



£ R 9900 



none O P 5170 ] 



£ R 9908 \ * 



P 5177 J 



(3) 8000 -1 o i -r 10100 



d P 5260 



^ R 9900 



none U P 



4 R 



o P 



5176 ] 

 9! OS \ 



5177 J 



complete balance. 



