[164] A chemical individual is a substance which persists as a phase of constant composition when the conditions of temperature, pressure, and composition of the other phases present, undergo continuous alteration within certain limits—the limits of existence of the substance (Wald, Zeitschr. physikal. Chem., 1897, 24. 648).
[165] Van't Hoff, Zeitschr. physikal. Chem., 1890, 5. 323; Ostwald, Lehrbuch, I. 606.
[166] That mercury does dissolve in water can be argued from analogy, say, with mercury and bromonaphthalene. At the ordinary temperature these two liquids appear to be quite insoluble in one another, but at a temperature of 280° the mercury dissolves in appreciable quantity; for on heating a tube containing bromonaphthalene over mercury the latter sublimes through the liquid bromonaphthalene and condenses on the upper surface of the tube.
[167] Phil. Mag., 1884, [5], 18. 22; 495.
[168] Wied. Annalen, 1886, 28. 305.
[169] Zeitschr. physikal. Chem., 1898, 26. 433.
[170] Rothmund, loc. cit.
[171] Rothmund, loc. cit.
[172] A similar behaviour is found in the case of diethylamine and water (R. T. Lattey, Phil. Mag., 1905, [6], 10, 397).
[173] C. S. Hudson, Zeitschr. physikal. Chem., 1904, 47. 113.