To-day in foreign countries where huge stretches of swamp bar the progress of the iron road the self-same principle is adopted, and it is known as “corduroying” or “cross-waying.” In the northern States, Canada and Siberia--the latter country and Canada especially--the “muskeg,” or “tundra,” as this treacherous land is called, often stretches for miles. One can sound it sedulously to a great depth, and then will fail to touch the bottom. The soddened decayed vegetable matter merely fills a large depression which cannot be drained. The builders waste no time attempting to build up a solid earthen embankment resting on the submerged solid floor of the bog. They fashion a huge mattress of trees. Large trunks are laid horizontally and longitudinally to the track. Upon these are laid transversely two or three layers of shorter logs, the whole being secured together firmly. A topmost layer of branches forming a kind of thatching completes the structure. At times these mattresses assume respectable proportions. I have stood beside some almost as thick as a man is tall, and they constituted quite formidable pieces of work. When the corduroy is completed a layer of rock is applied, and upon this is dumped the gravel and other material forming the embankment. Under the weight thus superimposed the mattress sinks deeply into the morass and rests firmly. The earthen ridge is continued to the requisite height; the whole of the embankment for the track rests upon the fabrication of tree-trunks. Yet the whole is just as solid as if resting upon granite. One might remark that it appears an indifferent foundation upon which to pile up a mass of earth weighing several hundred tons, and that in a short time the wood, under decomposition and collapse, would precipitate a subsidence. But as a matter of fact, the corduroy grows stronger with every passing day. The wood immersed in the viscous liquid and preserved from all contact with the atmosphere becomes waterlogged, until at last it assumes the character of bog-oak and is practically indestructible.