264 



APPENDIX TO EXPERIMENTAL SECTION. 



Measurements are made as follows : c being found by trial. 

 As a is to b so is c to d ohms. 



FIG. 59. Paul's Bridge Box. 



Kohlrausche's method for measuring the resistance of 

 electrolytes by means of alternating- currents and telephone. 



FIG. 60. Kohlrausche's Method. 



Insert a variable resistance R (of bridge box) into one gap of the metre bridge, 

 and the unknown resistance into another corresponding one at the other end. 

 Connect the telephone to opposite ends of the bridge wire, and the wires from the 

 S coil of an inductorium to the centre of the copper bars on one hand and the 

 rider J on the other. Or the bridge box may be employed instead by substituting 

 SC for the battery B, and the telephone for the galvanometer G. 



