356 Messrs. Threlfall and Pollock on the Clark Cell 



Clark cell remains unpolarized when changes of K are con- 

 sidered as evidences of polarization. In order to exhibit the 

 changes actually occurring in K, the following Table has been 

 prepared. To get the value of 0, corresponding to any 

 observed value of A, the experimental P.D. was taken and 

 divided by the external resistance. The table shows what the 

 cell variations actually are — expressed as if they were all to 

 be traced to actual changes of resistance. It will be noticed 

 that the values of K increase as the current diminishes, show- 

 ing that what is ordinarily called polarization is less with 

 greater currents than with small. It is fair, however, to state 

 that the variations of P.D. in the latter case were nearer to our 

 experimental limit of discrimination, and consequently are to 

 be treated as having less weight than those referring to 

 greater currents. 



Table I. 

 Table giving the value of K from the equation A = KC. 



Date. 



External 

 resistance. 



A. 



Terminal 

 P.D. 



Current. 



K. 





1888. 



L. ohms. 



TOlts. 



volts. 



amperes. 





July 26 



143 



0-04730 



1-38776 



0-009704 



4-874 





26 



143 



0-04590 



1-38911 



009714 



4-725 





26 



143 



04545 



1-38956 



0-009717 



4-677 





26 



143 



004606 



1-38913 



0009713 



4-741 





26 



494 



0-01593 



1-41917 



0-002872 



5-545 





•26 



987 



0-00729 



1-42781 



0-001446 



5-039 



T Mean of 13 obs. 





1423 



0005217 



1-430663 



0-001005 



5-189 



\ during July & 

 1 Aug. 

 Mean of 2 obs. 



July 24 



2862 



0-00254 



1-43323 



0-0005007 



5-072 



24 



4293 



000180 



1-43383 



00003339 



5-384 





Aug. 21 



10000 



0-00076 



1 -43538 



0-0001435 



5-295 



Mean of 2 obs. 



Oct. 22 



10000 



0-00079 



1-43448 



0-0001434 



5-507 



Mean of 4 obs. 



July 31 



20000 



0-00058 



1-43489 



000007174 



8-084 





31 



30000 



000045 



1-43507 



00004783 



9 407 





31 



40000 



000036 



1-43521 



0-00003588 



10-03 





31 



50000 



0-00027 



1-43530 



0-00002870 



9406 





31 



60000 



00023 



1-43539 



0-00002392 



9-614 





31 



70000 



0-00023 



1-43544 



0-00002050 



11-21 





31 



90000 



0-00018 



1-43554 



0-00001595 



11-28 





Nov. 1 



10000 



0-000630 



1-42837 



0-00014284 



4-415 



{Temp. 21° 6 C. 

 1 Mean of 2 obs. 



2 



10000 



0-000765 



1-42853 



0-00014285 



5-355 



Temp. 2l°-7 C. 



1 



10000 



0000630 



1-42107 



0-00014211 



4-433 



Temp. 34° -2 0. 



1 



10000 



0-000630 



1-42107 



000014211 



4-433 



Temp. 33°-9 C. 



1 



10000 



0-000630 



1-42117 



00014211 



4-433 



Temp. 33°-0 C. 



1 



10000 



0000720 



1-42158 



0-00014216 



5-064 



Temp. 32° -0 C. 



1 



1450 



000293 



1-41997 



0-00097931 



2-991 



Temp. 30° -9 C. 



1 



1450 



0-00257 



1-41913 



000097868 



2-626 



Temp. 30° '6 O. 



2 



1450 



0-00315 



1-42605 



0-00098351 



3-203 



Temp. 21°-7 0. 



