14 



is insensitive to the exact configuration of the electrode snarls . Another advantage 

 of a capillary-type cell is that the correction of the cell constant for both chang- 

 ing temperature and pressure is relatively simple. 



Since initial experiments suggested certain useful alterations in the 

 design of the first glass capillary cell, GCC-1<, a new cell, GCC-2, was con- 

 structed (Figure 9) . The arms of this cell are bridged with a glass brace for 

 added strength. Moreover, the volume of the reservoirs relative to that of the 

 capillary and electrode compartments has been increased, in order to prevent 

 the electrolyte level from falling below the upper electrode when high pressure 

 is applied. 



In order to reduce polarization, an aqueous chloroplatinic acid-lead 

 acetate solution and procedure described by Greightom'^) were used to platinize 

 the platinum electrodes of both cells . We found that we could not platinize the 

 electrodes of the capillary cell in the cell . Hence the platinum wires were 

 platinized outside of the cell. The cell was then filled with solid NaCl up to the 

 bottom of the upper electrode compartment. The platinized wire was fed into 

 that arm of the cell through plastic "spaghetti, " in order to avoid buckling in 

 the reservoir, and was pushed into the solid NaCl to form the initial kink. Once 

 the initial kink, which prevents the wire from entering the capillary, is formed, 

 the rest of the electrode snarl can be formed without difficulty . The solid NaCl 

 is next removed, and the electrode snarl in the lower electrode compartment 

 formed by feeding the pre -platinized wire in through "spaghetti." 



D. CONDUCTIVITY BRIDGE 



A Shedlovsky conductivity bridgeC^) with a Wagner earth connection, 

 based on the design of the bridge successfully used at the Sterling Chemistry 

 Laboratory of Yale University for precision electrical conductivity measure- 

 ments, has been constructed. The over -all arrangement of the principal com- 

 ponents is shown in Figure 10, and the details of a Leeds & Northrup Campbell- 

 Shackleton shielded ratio box are shown in Figure 11. 



S- 700 1-0307 



