190 Dr. C. E. A. Wright and Mr. C. Thompson. [May 3, 



currently with a notahle increase in the amount of corrosion of the 

 lead ; the following values were obtained during this period of two or 

 three hours whilst the readings were comparatively constant. 



Values of K 2 = effect of substituting Brightened Lead for 

 Amalgamated Zinc in mNa 2 O,100H 2 O. 





m = 1 • 75. 



vn =. 3 '45. 



m = 7*15. 





-0-690 



-0-703 



-0-708 





-0-668 



-0-681 



-0-678 





-0-678 



-0-690 



-0-691 



E.M.F. of Cells set up with Brightened Lead and wNa 2 O,100H 2 O. 





m = 1 -75. 



m = 3-45. 



m = 7-15. 





0-921 



0-928 



954 







0-873 







0-756 



0-773 



o'-776 





0-738 



0-758 



0-764 





0-738 



0-753 



0-768 





0-721 



738 



0-738 





0-717 



0-736 



0-745 





0-712 



733 



0-747 





0-704 



0-706 



0-737 







636 





Here, as with cells set up with zinc, the E.M.F. rises with the 

 solution-strength, but not to so great an extent, since the (negative) 

 value of K 2 also increases therewith. 



Cells set up with Dilute Sulphuric Acid and Copper as Oxidisable 



Metal. 



As a general rule, cells set up with dilute sulphuric acid showed 

 somewhat less steadiness, and wider limits of fluctuation between the 

 mean values of duplicates, than cells containing caustic soda ; but the 

 numbers obtained were sufficiently concordant to show that, cceteris 

 paribus, the E.M.F. of a copper-sulphuric acid aeration plate cell 

 increases with the solution-strength, and that practically no differ- 

 ence is noticeable between the mean value obtained with the thinnest 

 leaves and foils of the same metals up to 0*1 mm. in thickness. 



