hygroscope
(ˈhaɪgrəskəʊp)
[mod. f. Gr. ὑγρο- hygro- + -σκοπος observing. F. hygroscope.]
An instrument which indicates (without accurately measuring) the degree of humidity of the air.
Usually a device in which a vegetable or animal fibre (in Saussure's h., a human hair) which contracts with moisture, is made to move an index round a graduated scale as in the wheel barometer, or, in a familiar form, to make a small male or female figure emerge from a toy house.
| 1665 Phil. Trans. I. 31 A Hygroscope, or an Instrument, whereby the Watery steams, volatile in the Air, are discerned. 1665 Hooke Microgr. Table 252 Of a wild Oat..and..the manner of making an Hygroscope with it. 1679 Moxon Math. Dict., Hygrometer, an Instrument to measure the Moisture of the Air, it is also called by the Name of Hygroscope. 1790 De Luc in Phil. Trans. LXXXI. 11, I made two hygroscopes of different elastic animal substances. 1801 Monthly Rev. XXXV. 456 The hair hygrometer, or rather hygroscope. 1878 Huxley Physiogr. 70 The instrument..simply indicates the presence of moisture without accurately measuring its amount; it is in truth, a hygroscope rather than a hygrometer. |