ὑδροφαντική
From LSJ
ἀκίνδυνοι δ' ἀρεταὶ οὔτε παρ' ἀνδράσιν οὔτ' ἐν ναυσὶ κοίλαις τίμιαι → but excellence without danger is honored neither among men nor in hollow ships
English (LSJ)
(sc. τέχνη), ἡ, the art of discovering water, Gp. 2.6.1; also ὑδροφαντικά, τά, ibid.
German (Pape)
[Seite 1174] ἡ, sc. τέχνη, die Kunst, verborgenes Wasser zu entdecken.