A bore is a curling wave like a shore breaker that rushes down the smaller rivers, and is terribly destructive to boating or to shipping.
The Amazon, however, did not rise like this. It came rushing almost silently down in a broad tall wave that appeared to stretch right across it, from the forest-clad bank where the raft lay to the far-off green horizon in the north.
But Burly Bill was quite prepared for eventualities.
Steam had been got up, the vessel's bows were headed for up stream, and the hawser betwixt raft and boat tautened.
On and on rushed the huge wave. It towered above the raft, even when fifty yards away, in the most threatening manner, as if about to sweep all things to destruction.
But on its nearer approach it glided in under the raft, and steamer as well--like some huge submarine monster such as we read of in fairy books of the long-long-ago--glided in under them, and seemed to lift them sky-high.
"Go ahead at full speed!"
It was the sonorous voice of Burly Bill shouting to the engineer.
"Ay, ay, sir!" came the cheery reply.
The screw went round with a rush.