Our companions were to spend some months engaged in the occupation I have described; till the return of spring, in fact, when, the rafts being put together, they would descend the river till rapids or cataracts were reached.  The rafts would then be separated, and each log of timber, or two or three together at most, would be allowed to make their way as they best could down the fall, till they reached calm water at the foot of it; when they would be again put together, and navigated by the raftsmen guiding them with long poles.  In some places, where rough rocks exist in the rapids by which the timber might be injured, slides had been formed.  These slides are channels, or rather canals, as they are open at the top; and are constructed of thick boards--just as much water being allowed to rush down them as will drive on the logs. Some of these slides are two hundred feet long; others reach even to the length of seven hundred feet.  The timbers are placed on cribs,--which are frames to fit the slides,--then, with a couple of men on them to guide their course, when they get through they shoot away at a furious rate down the inclined plane, and without the slightest risk of injury.