This article, titled "A Contribution to the Theory of Electrocapillarity," by David Leonard Chapman, published in the Philosophical Magazine Series 6, explores the theoretical aspects of electrocapillarity. The author discusses the behavior of capillary discharges, particularly in dilute sulfuric acid, and the appearance of metal lines in the spectrum. He presents equations to describe the potential and electric density within a solution, focusing on the double-layer theory. Chapman derives a differential equation to determine the electric state of any point in the field and calculates the charge on the double-layer condenser. He also provides a method to calculate the surface energy of mercury in contact with an electrolyte and discusses the electrification associated with dust-clouds. The article emphasizes the importance of experimental verification of the theoretical predictions and suggests further research in the region of maximum capillarity.This article, titled "A Contribution to the Theory of Electrocapillarity," by David Leonard Chapman, published in the Philosophical Magazine Series 6, explores the theoretical aspects of electrocapillarity. The author discusses the behavior of capillary discharges, particularly in dilute sulfuric acid, and the appearance of metal lines in the spectrum. He presents equations to describe the potential and electric density within a solution, focusing on the double-layer theory. Chapman derives a differential equation to determine the electric state of any point in the field and calculates the charge on the double-layer condenser. He also provides a method to calculate the surface energy of mercury in contact with an electrolyte and discusses the electrification associated with dust-clouds. The article emphasizes the importance of experimental verification of the theoretical predictions and suggests further research in the region of maximum capillarity.