ˈwater-ˌlevel
1. A levelling instrument in which water is used instead of alcohol (see quot. 1880).
| 1563 Shute Archit. B ij b, Geometrie teacheth vs the order of rules, Compasses, Squiers, Quadrantes, and Iuste water⁓leueles with manie other knowlaiges. 1674 R. Hooke Animadv. Hevelius 61 This is done by the help of a Water-Level. 1723 E. Stone tr. Bion's Math. Instrum. v. i. (1758) 134 The first of these Instruments is a Water-Level, composed of a round Tube of Brass, or other solid Matter, about 3 Feet long [etc.]... This Level, altho' very simple, is very commodious for levelling short Distances. 1880 L. D'A. Jackson Aid Surv.-Pract. 146 The water level..is also an appliance for rough levelling within short distances... It consists of a horizontal tube about two feet long terminated by two bottle-shaped ends, in which water will stand level and thus afford a horizontal line of sight. |
2. Mining. A road driven on the strike of a seam to carry off water.
| 1698 Phil. Trans. XX. 368 It is only a Spring which rises in a Coal-Drift (or Water-Level made for the draining of the Cannel Coal-Pits). 1836 Hull & Selby Rlwy. Act 43 Airways, headways, gateways, or water-levels through the mines. 1886 J. Barrowman Sc. Mining Terms 71. |
3. The plane below which the rock or soil is saturated with water; the situation of this plane. Also attrib.
| 1839 Ure Dict. Arts 960 To whatever depth a coal-mine is drained of its water, from that depth it is worked, up to the rise of the water-level line. Ibid. 974 The miner..is guided in his line of direction entirely by the water-level. 1882 Geikie Text-bk. Geol. iii. ii. ii. §2. 345 In most districts rocks are permeated with water below a certain limit termed the water-level. |
4. The horizontal surface of still water. Also the (higher or lower) position of the surface of water.
| 1860 Maury Phys. Geog. Sea (Low) xii. 297 Thus we might have a sea whose level would be much further below the water-level of the ocean than is the Dead Sea. 1862 Smiles Engineers III. iii. 26 When the water-level in the pit was lowered, and the suction became incomplete [etc.]. 1878 D. Kemp Man. Yacht Sailing 377 A straight line from the fore side of the stem to the aft side of the stern-post at the water level. 1895 J. J. Raven Hist. Suffolk 39 The salting mound just above the present average water-level in Herringfleet. 1917 L. Einstein Inside Constantinople v. 212 The crew..succeeded in raising the stern [of the submarine] to the water-level, whence all scrambled out. |