in half an hour a great wave several feet in height, could be distinctly seen flashing and sparkling in the moonlight, extending from one bank to the other and advancing swiftly upon us. While it was only a few hundred yards distant, the ebb tide continued to flow by at the rate of three miles an hour. A point of land and an exposed bar close under our lee broke the wave into several long swells, and as these met the ebb the broad sheet around us boiled up and foamed like the surface of a cauldron, and then, with scarcely a moment of slack water, the whole went whirling by in the opposite direction. In a few moments the low rollers had passed the islands and united again in a single bank of water, which swept up the narrowing channel with the thunder of a cataract.