INORGANIC RESPONSE 



93 



limbs of the tube are now filled with water, till the 

 ends A and B are completely immersed. Connection 

 is made with the non-polarisable electrodes by the 

 side tubes. Vibration may be imparted to either A or 

 B by means of ebonite clip holders seen at the upper 

 ends A B of the wire. 



fa/) 



FIG. 55. SUCCESSIVE MODIFICATIONS OF THE BLOCK METHOD FROM THE 

 ' STRAIGHT WIRE ' (a) TO ' CELL FORM ' (e) 



When A is excited, current of response in the wire is from less excited B to 

 more excited A. Note that though the current of response is constant in 

 direction, the galvanometer deflection in (d) will be opposite to that in (6). 



It will be seen that the two limbs of the tube filled 

 with water serve the purpose of the strip of moistened 

 cloth used in the last experiment to make electric 

 connections with the leading-out electrodes with the 

 advantage that we have here no chance of any shifting 

 of contact or variation of surface, the contact between 



