276 



MORRIS LOEB 



tube ends in a bulb, and upon this is set a narrower vertical 

 tube, through which the negative electrode a cylindrical 



roll of silver foil fastened to a sil- 

 ver wire can be let down into 

 the bulb. This works as a sort 

 of pocket, by which masses of the 

 spongy precipitated silver that 

 may become detached from the 

 electrode are prevented from stir- 

 ring up the body of the solution. 

 The anode consists of a silver wire 

 rolled into a spiral at the lower 

 end. It is introduced through A, 

 and reaches to the bottom of the 

 main tube. In order that the cur- 

 rent may enter the liquid only 

 at the spiral, the straight part of 

 the wire is covered with a capillary of very thin glass, which 

 can be closed around the wire by fusion, in spite of the 

 difference in their coefficients of expansion. The openings 

 A and B are closed with corks that are traversed by short 

 glass tubes. Of these, the tube at A allows free passage to the 

 wire of the electrode. The wall of the tube at B is pierced by 

 a platinum wire, which serves to suspend the cathode and to 

 connect it with the conductor of the battery. Thus A can be 

 closed by the compression of a bit of rubber tubing drawn 

 over the wire and glass tube, or air can be sucked or blown 

 through a rubber tube connected with B, without disturb- 

 ing the electrodes. 



[109] In experimenting, such an apparatus would first be 

 weighed with its electrodes and stoppers, but without the 

 rubber tubing. The latter was hereupon put in position, A 

 was closed with a pinch-cock as just indicated, and air was 



