Sources of error in the measurement of the electrical charge of colloidal particles by the method of moving boundaries: an improved method based on a direct measurement of the potential gradient across the boundary
In a series of papers (J. Amer. Chem. Soc.,' vol. 37, p. 2024, 1915; and Sen,'Trans. Chem. Soc.,' vol. 115, p. 461 (1919); ibid , vol. 117, p. 350 (1920); and Papaconstantinou, ibid ., vol. 117, p. 1563 (1920)) the writer has studied the influences which the dilution of the sol, the degree of dispersion, the amount of the peptising electrolyte or other substances and the temperature, have on the rate of coagulation. The importance of the charge of the colloidal particles on their stability has been well established through the works of Hardy, 'J. of Physiol.,' vol. 24, p. 288 (1899); Burton, 'Phil. Mag.,' [6], vol. 12, p. 472 (1906); vol. 17, p. 583 (1909); also [6], vol. 11, p. 426 (1906); Galecki, 'Zeit. Anorg. Chem.,'vol. 74, p. 129 (1912); Ellis, 'Z. Phys. Chem.,' vol. 78, p. 321 (1911); vol. 80, p. 597 (1912); and Powis, ibid ., vol. 89, pp. 91 and 186. For a satisfactory theoretical discussion of the results on the rate of coagulation it is therefore necessary to know what effects the factors mentioned above have on the charge of the particles.