CONTENTS xxiii 



XVIII. Surfaces of Solids 670 



60. The Surface Energy and Surface Tension of the 



Surface of a SoUd 670 



61. Contact Angles. The Adhesion of a Liquid to a 



Sohd, Heat of Wetting 675 



XIX. Discontinuity of Electric Potential at a Surface. Elec- 



trocapiUarity 678 



62. Volta's Contact Potential between Two Metals 



and Its Connection with Thermoelectric and 

 Photoelectric Phenomena 678 



63. Discontinuity of Potential between a Metal and 



an Electrolyte 684 



64. Gibbs' Comments on Electrode Potentials 687 



65. Lippmann's Work on ElectrocapiUarity and Its 



Connection with Gibbs' Equation [690] 688 



66. The Double-Layer Hypothesis of Helmholtz 691 



67. Recent Developments in the Thermodynamical 



Treatment of ElectrocapiUarity 692 



68. The Reason Why Gibbs' Derivation of His Electro- 



capillarity Equation [690] Exhibits It as Equiva- 

 lent to Lippmann's Equation 697 



69. Guggenheim's Electrochemical Potential of an Ion. 698 



70. Derivation by Means of the Postulate of "Specific 



Adsorption" of Ions of an Equation Combining 

 Gibbs' Terms for Ions with a Lippmann Term for 

 Electrons 700 



71. Some Brief Remarks on the Fundamental Electri- 



cal Equations Used by Stern in His Treatment 

 of the Distribution of Ions in a Solution Close 

 to the Cathode of a Capillary Electrometer 704 



M. The General Properties of a Perfect Electro- 

 chemical Apparatus. Electrochemical Thermo- 

 dynamics (Gibbs I, pp. 338-349; 406-412), H. S. 



Harned 709 



I. The General Thermodynamics as Explicitly Developed . . 709 

 II. On the Question of Absorption or Evolution of Heat 



During Galvanic Processes 717 



III. The Extension of the Theory of Galvanic Cells Not Ex- 



plicitly Developed, but Contained ImpUcitly in the 

 Thermodynamics of Gibbs 720 



IV. Developments of Importance to the Theory of the Physi- 



cal Chemistry of Solutions since Gibbs 724 



Indexes 737 



