Then the spirit of the pioneer stirred within his soul. The wilderness sent forth its old-time challenge to the hardy. In him awoke that instinct which, without itself perceiving the end on which it is bent, clears the way for the civilization that has been ripening in old-world hot-houses during a thousand years. Men must eat; and so the soil must be made productive. We regret, each after his manner, the passing of the Indian, the buffalo, the great pine forests, for they are of the picturesque; but we live gladly on the product of the farms that have taken their places. Southern Michigan was once a pine forest: now the twisted stump-fences about the most fertile farms of the north alone break the expanse of prairie and of trim “wood-lots.” Thorpe knew little of this, and cared less. These feathered trees, standing close-ranked and yet each isolate in the dignity and gravity of a sphinx of stone set to dancing his blood of the frontiersman. He spread out his map to make sure that so valuable a clump of timber remained still unclaimed. A few sections lying near the headwaters were all he found marked as sold. He resumed his tramp light-heartedly. At the ten-mile point he came upon a dam. It was a crude dam,--built of logs,--whose face consisted of strong buttresses slanted up-stream, and whose sheer was made of unbarked timbers laid smoothly side by side at the required angle. At present its gate was open. Thorpe could see that it was an unusually large gate, with a powerful apparatus for the raising and the lowering of it. The purpose of the dam in this new country did not puzzle him in the least, but its presence bewildered him. Such constructions are often thrown across logging streams at proper intervals in order that the operator may be independent of the spring freshets. When he wishes to “drive” his logs to the mouth of the stream, he first accumulates a head of water behind his dams, and then, by lifting the gates, creates an artificial freshet sufficient to float his timber to the pool formed by the next dam below. The device is common enough; but it is expensive. People do not build dams except in the certainty of some years of logging, and quite extensive logging at that. If the stream happens to be navigable, the promoter must first get an Improvement Charter from a board of control appointed by the State. So Thorpe knew that he had to deal, not with a hand-to-mouth-timber-thief, but with a great company preparing to log the country on a big scale.