5fi6 



MR. F. E. SMITH, MR. T. MATHER, AND DR. T. M. LOWRY 



Elevated Kathode Type. 



The results are given below (Table VI.) and call for no comment. No difference 

 from the usual type was anticipated, for the Rayleigh and syphon forms had been 

 found to agree before the first of the observations in Table VI. had been made. 



TABLE VI. Comparison of the Elevated Kathode Voltameter with the Rayleigh 



Voltameter (I'll 827). 



No. 



516* 

 51rf* 

 82c 



Milligrammes per 

 coulomb. 



1-11829 

 26 

 24 



Difference from 

 mean. 



+ 3 







Mean = 1-11826 

 * Absolute determinations. 



Efficiency of Porous Pots and of Syphons. 



Nearly all previous researches have led to the conclusion that a source of trouble 

 exists at the anode, and the porous pot voltameter was designed by RICHARDS to 

 prevent the anode liquid having access to the kathode. NOVAK* was the first to 

 suggest the possible existence of a complex silver salt in the electrolyte ; RODGER 

 and WATSON! independently made the same suggestion ; RICHARDS'^ experiments 

 strengthened the view, and the work of KAHLE, GUTHE,|| VAN DiJK.1I and others 

 supports the theory of anode complications. When the very excellent work of these 

 observers is reviewed the results of our observations are astonishing, and we deem it 

 necessary to give evidence of the reliability of our porous pots and syphons. 



When the porous pots of classes (1) and (2) were filled with water and allowed to 

 stand for 12 hours, about 40 per cent, of the liquid appeared to pass through their 

 walls. When pots of class (3) were similarly treated, less than 5 per cent, of the 

 liquid passed through the pots. In one of the pots of class (3) 50 cub. centims. of the 

 electrolyte used in observation 30c, which gave a deposit of 1 '12055 milligrammes 

 per coulomb, were used for the anode liquid in observation 49c, the kathode liquid 

 being normal AgNO s solution. The result is 1*11827, showing that very little of the 



* NOVAK, 'Proc. Roy. Bohemian Ac. ScL Prague,' 1, pp. 387-432, 1892. 



t RODGER and WATSON, ' Phil. Trans., ' A, 186, p. 631, 1895. 



t RICHARDS, COLLINS and HEIMROD, 'Proc. Am. Ac.,' 35, p. 123, 1899. 



KAHLE, 'Zeitschr. Inst.,' 18, pp. 229-267, 1898. 



|| GUTHE. 'Phys. Rev.,' 19, p. 138, 1904; 'Bull. Bureau of Stands.,' vol. 1, pp. 28 and 349, 1904. 



U VAN DIJK and KUNST, ' Ann. der Phys.,' 14, p. 569, 1904 ; VAN DIJK, 'Ann. der Phys.,' 19, p. 249, 1906. 



