about four o'clock
I 've been wet before . '' `` No use taking chances . '' From the canyon they were unable to watch the sky , since only a strip of the zenith was visible . The flat ledge about the watch-tower was the only level spot large enough for single-stick exercise , and they were still practicing there when , at about four o'clock , a tremendous roll of thunder echoed between the cliffs and the atmosphere suddenly became thick . Fred thrust the sticks in a cleft in the rock . `` We 're in for it , Thea . Better make for your cave where there are blankets . ''