When the traffic in the streets of London became so great that the ordinary thoroughfares were unable to meet public requirements, the bold project was conceived of making a railway under the streets. The construction of a line of railway beneath the streets of a populous city, amidst a labyrinth of gas-pipes, water-mains, sewers, &c., is obviously an undertaking presenting features so remarkable that the London Underground Railway cannot here be passed over without a short notice. Its construction occupied about three years, and it was opened for traffic in 1863. The line commencing at Paddington, and passing beneath Edgware Road at right angles, reaches Marylebone Road, under the centre of which it proceeds, and passing beneath the houses at one end of Park Crescent, Portland Place, it follows the centre of Euston Road to King’s Cross, where connection with the Great Northern and Midland system is effected. Here the line bends sharply southwards, and proceeds to Farringdon Street Station, the original terminus. A subsequent extension takes an easterly direction and reaches Aldgate Station, the nominal terminus. The crown of the arch which covers the line is in some places only a few inches beneath the level of the streets; in other places it is several feet below the surface, and, in fact, beneath the foundations of the houses and other buildings. The steepest gradient on the line is 1 in 100, and the sharpest curve has a radius of 200 yards. The line is nearly all curved, there not being in all its length three-quarters of a mile of straight rails. The difficulties besetting an undertaking of this kind would be tedious to describe, but may readily be imagined. The line traverses every kind of soil—clay, gravel, sand, rubbish, all loosened by previous excavations for drains, pipes, foundations, &c.; and the arrangements of these drains, water and gas-pipes, had to be reconciled with the progress of the railway works, without their uses being interfered with even for a time. Of the stations the majority have roofs of the ordinary kind, open to the sky; but two of them, namely, Baker Street and Gower Street, are completely underground stations, and their roofs are formed by the arches of brickwork immediately below the streets. The arrangements at these stations show great boldness and inventiveness of design. The booking offices for the up line are on one side of the road, and those for the down line on the other. Fig. 50 represents the interior of the Gower Street Station, and the other is very similar. In each the platforms are 325 ft. long and 10 ft. broad, and the stations are lighted by lateral openings through the springing of the arch which forms the roof. This arch is a portion of a circle of 32 ft. radius, with a span of 45 ft. and a rise of 9 ft. at the crown. The lateral openings are arched at the top and bottom, but the sides are flat. The width of each is 4 ft. 9 in., and the height outside 6 ft., increasing to 10 ft. at the ends