hydroscope
(ˈhaɪdrəʊskəʊp)
[mod. ad. Gr. ὑδροσκόπ-ος (f. ὑδρο- water + -σκοπος -scope) water-seeker, well-sinker, and ὑδροσκόπιον water-clock (Synesius). In F. hydroscope water-searcher.]
† 1. An instrument for the detection of moisture in the air; a hygroscope. Obs.
| 1678 Phillips (ed. 4), Hydroscope, a certain Instrument..for discerning of the Watry volatil streams in the Air. 1721 in Bailey. Hence in Mod. Dicts. |
2. A kind of water-clock. Hist.
It consisted of a cylindrical graduated tube, filled with water, which trickled through an aperture in the conical bottom, and marked by its subsidence the successive hours.
| 1727–41 in Chambers Cycl. 1809 Naval Chron. XXI. 375 The chief part of this machine is a hydroscope. |