"Thunder, by Jove!" exclaimed Warkworth.
In a few minutes the roar increased. It certainly was not thunder. The Sea Scouts looked at each other inquiringly.
They observed, also, that there was great activity on board the small boats at Quillebeuf. Men were busy casting off moorings and rowing the little craft into the centre of the stream.
Suddenly round a bend in the river, down-stream, a huge wall of water was seen approaching at a furious rate and breaking heavily against both banks. To the lads this moving mass appeared to be quite twenty feet high, but in reality it was about one third that height.
It was the bore, or "La Barre"—a tidal wave caused by the flood tide forcing its way into the funnel-shaped estuary and overwhelming the ebb.
"Hang on to something, all hands!" shouted Mr. Armitage. "Hard-a-starboard, Peter."
Round swung the Olivette until her bows pointed down-stream.
"Easy ahead!" was the next order.
Straight for the centre of the bow-shaped wall of water the staunch little craft headed. Into it she plunged, thrusting her bluff snout deep into the wave. A foaming torrent swept the foredeck, and, breaking against the wheel-house, flew high in the air in a cloud of spray.
For a few seconds it seemed as if the Olivette were standing on her heel. Her momentum was temporarily stopped. Somewhere below, the sound audible above the roar of the bore, came the crash of broken glass. Then with a dizzy, disconcerting movement the boat slid down the reverse side of the liquid wall into the agitated water beyond.