542 Mr. J. J. Dowling and Miss K. M. Preston on the 



galvanometer deflexion (shunted 3 Jo) were made. A curve 

 so obtained is shown in fig. 5 *. By a method of substitution 

 the resistance o£ an electrolyte can be easily obtained ; but, 

 to attain the highest accuracy, the following procedure is 

 necessary. 



§ 9. Having introduced the electrolytic resistance in the 

 circuit RY, the resistance T is changed until the galvanometer 

 is at zero. The galvanometer shunt S may then be reduced 

 to unity and the galvanometer reading taken. Having 

 restored the shunt S to a high value the electrolyte is removed, 

 and, by means of a suitable set of non-inductive resistances, 



Fig. 5. 



400 



200 











y/ 



1 











« 



Si 



» 







c 



> 



CO 

 O 















Ohms. 



20 



40 



60 



a resistance of nearly the same value is introduced at R in 

 place of the electrolyte. On again reducing the galvanometer 

 shunt a second reading is obtained. The difference between 

 the two galvanometer readings is proportional to that between 

 the electrolyte and the known resistance, in virtue of the 

 linear relation shown in fig. 6. For calibration it is simply 

 necessary to alter the known resistance by a small amount 

 and to observe the effect on the galvanometer. 



Great precision is obtainable in resistance determinations 

 by this method. A consideration of fig. 5 shows this. The 



* The curve starts from zero because of the previous adjustment of the 

 potential balancing- device TE. Galvanometer sensitivity =10 -8 amp. 

 per div. 



