water-gall
Wa"ter gall`. 1. A cavity made in the earth by a torrent of water; a washout. 2. A watery appearance in the sky, accompanying the rainbow; a secondary or broken rainbow. These water galls, in her dim element, Foretell new storms to those already spent. Shak. False good news are [is] always produced by true good, like the water gall by the rainbow. Walpole.