In the morning we slept lazily long, and breakfasted at Rubiaan, the first well in Wadi Ais. Afterwards we were smoking and talking, about to bring in the camels, when suddenly we felt the distant shock of a great explosion behind us on the railway. We wondered if the mine had been discovered or had done its duty. Two scouts had been left to report, and we rode slowly; for them, and because the rain two days ago had brought down Wadi Ais once more in flood, and its bed was all flecked over with shallow pools of soft, grey water, between banks of silvery mud, which the current had rippled into fish-scales. The warmth of the sun made the surface like fine glue, on which our helpless camels sprawled comically, or went down with a force and completeness surprising in such dignified beasts. Their tempers were roughened each time by our fit of mirth.