hygroscopic, a.
(haɪgrəʊˈskɒpɪk)
[f. as prec. + -ic. Cf. F. hygroscopique.]
1. Pertaining to the hygroscope or hygroscopy; relating to the degree of humidity of the air, hygrometric.
| 1775 Ash, Hygroscopic, belonging to the hygroscope. 1836 Macgillivray tr. Humboldt's Trav. xxiii. 332 Experiments on the constitution of the air,—its elasticity, its electrical, magnetic, and hygroscopic qualities. |
2. spec. Said of bodies which readily absorb moisture from the air, so as to swell up, contract in length, or change form or consistence, and thus indicate roughly the presence or absence of humidity; sensitive to moisture.
| 1790 De Luc in Phil. Trans. LXXXI. 2 An hygroscopic body, which is not brought into contact with any other body drier than itself, cannot lose any part of its moisture but by evaporation. 1875 H. C. Wood Therap. (1879) 583 Glycerine..is very hygroscopic, and absorbs water from the air. 1880 C. & F. Darwin Movem. Pl. 489 The hygroscopic movements of plants. |
3. = hygrometric 3.
| 1862 Lond. Rev. 26 July 85 Moisture, but not in the form of rain..aqueous vapour in the air, and hygroscopic moisture in the soil. 1885 G. L. Goodale Physiol. Bot. (1892) 242 Water..which adheres to the particles of an air-dry soil and which does not affect at all the appearance of the particles..has been called..hygroscopic water. |