At flood tide sail was made on her as soon as she floated, and we succeeded in getting her back into the channel.

As the vessel grounded at every ebb tide and on the return of the water was violently swung around, thumping on her bottom and swinging on her anchor, I began to see that it would be neither prudent, or in fact possible, to ascend the river much higher, and we accordingly commenced making preparations for a boating expedition."* * Reconnaissance of the Gulf of California and the Colorado River made in 1850-51, by Lieut.

G.H.Derby.

Ex.

Doc, 81, 32nd Congress, 1st Session, Senate.
The ebb tide ran at the rate of five and a half miles an hour, and the next day they saw, as it was running out, the "bore," or tidal wave, booming in to meet and overwhelm it.
"A bank of water some four feet in height, extending clear across the river, was seen approaching us with equal velocity; this huge comber wave came steadily onward, occasionally breaking as it rushed over shoals of Gull and Pelican islands; passing the vessel, which it swung around on its course, it continued up the river.