(See quots.)
1705. Phillips (ed. Kersey), Water-gage … an Instrument to gage or measure the Quantity or Depth of any Water.
1844. Stephens, Bk. Farm, II. 316. When the boiler is observed to have got a sufficient supply—which is indicated by a float water-gauge—the discharge from the pump is turned off.
1886. J. Barrowman, Sc. Mining Terms, 71. Water-gauge, a U-shaped glass tube for measuring the difference of pressure between the intake and return air; an indicator showing the quantity of water in a steam boiler; a notched board for measuring flow of water.
attrib. 1883. W. C. Russell, Sailors’ Lang., Water-gauge cocks, small cocks placed in front of a marine boiler, by opening which the height of the water in the boiler is ascertained.
[Water-gauge, -gage, explained in many Dicts. to mean ‘a sea-wall or bank to restrain the current and overflowing of the water,’ is a spurious word, evolved from the false reading watergaugia, -iis, -iorum for watergangia, etc. (= WATERGANG 2) in the 1597 edition of a Romney charter of 1252.
The explanation was given in Spelman’s Glossarium (1664), whence it was copied in the Dictionarium Rusticum (1701), followed by Phillips (ed. Kersey, 1706) and later Dicts.)
