I '' ! 



II. On the. Nature of Ekctrooap&CH'y /'/"'nomena. I. Their Jf>/'itin,, t<> tin- !'< 



I Differences between Solutions. 



By S. W. ,T. SMITH, M.A., /,;, rl tl ('//*- 7Y..w,r Student of Trinity College, 

 ( 'ninln'idge ; Demonstrator of Phy.*i<-x in tin- Ifni/al College of Science, London. 



Communicated by Professor A. W. KIVKKK. .S-< . Jt.S. 

 Received .laiuuiry 5, Bead January 26, 1899. 



TAULK OK < 'ONTKNTS. 



FV 



Introduction 48 



The 1 .ippmann-Hclmholtz theory of elect rocapillary phenomena 49 



1. The first hypothesis of the Lippmunn-Helmholtz theory. The effect of depolari- 



zation. Experimental determination of the magnitude of the depolarization current. 50 



2. The second hypothesis of the Lippmaim-IIrlinholtz theory 87 



The relation Iwtween the Lippmaiin-IIclmholtz theory and other theories of clectrocapilliu y 



phenomena 58 



The discrepancy between the Lippmann-Helmholtz theory and the Nernst-Planck theory of 



the potential difference between solutions 59 



Solutions of potassium chloride and potassium iodide 62 



1. The potential difference between equally concentrated solution* 62 



2. The nature of the electrocapillary curves for the same solutions ........ 62 



a. General character of electrocapillary curves 62 



A. Definite nature of the " descending " branched 63 



Method adopted in the present examination of the electrocapillary curves and 



discussion of the degree of accuracy attainable in the experiments 63 



</. The electrocapillary curves for KCI and KI 66 



1. Preliminary experiment M 



2. Final experiment* showing the agreement of the first hv|x)tliesis of the 



Lippmann-Hchnholtz theory with the Ncrnst-Planck theory of the 



potential difference between KCI and KI 69 



. i mi nation of other known discrepancies between the Lippnmnn-Helmholu theory and the 



Nernst-Planck theory 74 



1 . Solutions of potassium chloride and potassium sulphocyanide 74 



2. Solutions of potassium chloride and sodium sulphide 74 



The relation Iwtween the nature of the kation of the solution and the form of the electnt- 



capillary curve 77 



Experiments with equally concentrated solutions of potassium and sodium chlorides .... 77 

 Relation l>etween the surface tension for a given potential difference and the concentration of 



the solution employed in the electrometer . . . 80 



Relation between the electrocapillary curve measurements for KCI and KI, and dropping 



1 nir.iMiii'incnts fur >iilutinii< of these salts 83 



U.7.M 



