Note 325 — Chapter VI · A NOTE ON ADSORPTION

The first instance of what we now call an adsorptive phenomenon was observed in soap-bubbles. Leidenfrost, in 1756, was aware that the outer layer of the bubble was covered by an “oily” layer. A hundred years later Dupré shewed that in a soap-solution the soap tends to concentrate at the surface, so that the surface-tension of a very weak solution is very little different from that of a strong one (Théorie mécanique de la chaleur, 1869, p. 376; cf. Plateau, II, p. 100).