These meadows, though not designed by the beavers, are yet useful to them, for, as Mr. Morgan says: “In addition to the nutriment which the roots of these grasses afford to the beavers, the meadows themselves are clearings in the wilderness, by means of which the light as well as the heat of the sun is let in upon their lodges.” Of course, when land that was once dry becomes overflowed with water, when peculiar-looking meadows appear, that were not there before, when canals wind about through them, and when trees that were formerly abundant grow thinner or even disappear, a considerable change takes place in the appearance of the country; and so numerous, till lately, were beavers in North America, that a very large extent of territory may be said to be the work, not, indeed, of their hands, but of their paws and teeth. Sometimes the Indians have been alarmed at the number of trees cut down by these animals, thinking they would not have sufficient fuel for their own encampments, but here, I think, they must have feared without cause, since beavers and trees have both been plentiful in the country from time immemorial. On one occasion, however, by making a dam across a small stream running parallel with one of the principal railway lines of Canada, the beavers produced an accumulation of water against the railway embankment. As it was feared that the line might be flooded, or the earth supporting it weakened, with possible disastrous consequences, a cutting was made through the centre of the dam, thus lowering the water to its original level. The beavers, however, were accustomed to repairing their dams, and did so in this instance. The company again cut the dam, the beavers again repaired it, and this conflict between an animal and one of the chief commercial enterprises of the country continued, till the dam, having been fifteen times cut through, was at length abandoned by its architects. This shows, certainly, great perseverance on the part of the beavers, but it shows also that they are capable of learning by experience. Why the dam should be always cut through, they could not, probably, conceive, and experience had hitherto taught them that the proper way of dealing with a breach was by repairing it. It now taught them that there were some breaches which it was no good to repair, and perhaps it took them no longer to learn, or, rather, to infer this, than, under similar circumstances, it would have taken ourselves. A general will often try many assaults upon a fortified place before he comes to the conclusion that it is too strong to be taken.