"It was urged by Mr. Brunel, as a justification for more attention and expense in the laying of the rails of the Great Western, than had been ever thought of upon previously constructed lines, that all the embankments and cuttings, and earthworks and stations, and law and parliamentary expenses—in fact, the whole of the outlay encountered in the formation of a railway, had for its main and ultimate object _a perfectly smooth and level line of rail_; that to turn stingy at this point, just when you had arrived at the great ultimatum of the whole proceedings, viz: the iron wheel-track, was a sort of saving which evinced a want of true preception of the great object of all the labor that had preceded it. It may seem curious to our experiences, in these days, that such a doctrine could ever have needed to be enforced by argument; yet no one will deem it wonderful who has personally witnessed the unaccountable and ever new difficulty of getting proper attention paid to the leveling of the bottom of a drain, and the laying of the tiles in that continuous line, where one single depression or irregularity, by collecting the water at that spot, year after year, tends toward the eventual stoppage of the whole drain, through two distinct causes, the softening of the foundation underneath the sole, or tile flange, and the deposit of soil inside the tile from the water collected at the spot, and standing there after the rest had run off. Every depression, however slight, is constantly doing this mischief in every drain where the fall is but trifling; and if to the two consequences above mentioned, we may add the decomposition of the tile itself by the action of water long stagnant within it, we may deduce that every tile-drain laid with these imperfections in the finishing of the bottom, has a tendency toward obliteration, out of all reasonable proportion with that of a well-burnt tile laid on a perfectly even inclination, which, humanly speaking, may be called a permanent thing. An open ditch cut by the most skillful workman, in the summer, affords the best illustration of this underground mischief. Nothing can look smoother and more even than the bottom, until that uncompromising test of accurate levels, the water, makes its appearance: all on a sudden the whole scene is changed, the eye-accredited level vanishes as if some earthquake had taken place: here, there is a gravelly _scour_, along which the stream rushes in a thousand little angry-looking ripples; there, it hangs and looks as dull and heavy as if it had given up running at all, as a useless waste of energy; in another place, a few dead leaves or sticks, or a morsel of soil broken from the side, dams back the water for a considerable distance, occasioning a deposit of soil along the whole reach, greater in proportion to the quantity and the muddiness of the water detained. All this shows the paramount importance of perfect evenness in the bed on which the tiles are laid. _The worst laid tile is