The longest canal tunnel—indeed, the longest tunnel, whether railway or canal—in England is the Marsden, on the Huddersfield Canal, 5,450 yards (3 miles and 170 yards), thus exceeding the longest railway tunnel by 154 yards. The lengths in yards of some of the principal canal tunnels of England are as follows:—Sapperton (Thames and Severn), 4,180; Lapal (Dudley), 3,776; Blisworth (Grand Junction), 3,080; Tipton Green, 2,926; Oxenhall, 2,192; Foulbridge (Leeds and Liverpool), 1,640; Asperton (Hereford and Gloucester), 1,320; Fenny Compton (Oxford), 1,188. From this list we exclude the Old Thames and Medway Canal Tunnel, near Rochester, because the South-Eastern Railway Company, when it purchased the canal, converted the tunnel into one suitable for a railway; its length is 3,740 yards. The most recently constructed canal tunnel in England is the Netherton Tunnel, on a branch of the Birmingham Canal, having only been completed in 1858. It is 3,036 yards long, 27 feet wide, and 24 feet 4 inches high in the clear. Seventeen shafts altogether were sunk during its construction, of which ten were closed on being used for traffic. The greatest depth of any of the shafts is 344 feet 6 inches, the least 65 feet 9 inches. The time occupied for completing this tunnel was only two years. For full and minute description of this tunnel see proceedings of the “Institution of Civil Engineers,” Vol. XIX. The village of Highgate, situated on one of the two northern hills in the immediate vicinity of London, was to have had a tunnel 301 feet long, 24 feet wide, and 13 feet high, for the purpose of avoiding the steep and dangerous hill on the great road which led, and still leads from London, towards the North. An Act of Incorporation was obtained, and the undertaking was prosecuted for a time with great energy; but unfortunately, after 130 yards of the work had been accomplished, the whole fell in on the 13th of April, 1812. The accident created an intense sensation, and it was the subject of a drama: “The Highgate Tunnel, or the Secret Arch,” which for a time was a source of attraction at one of the minor theatres at the East end of London. The disaster put an end to the desire for a tunnel, and the present road was constructed through a deep cutting, by means of which much of the steepness of the hill was done away with. Hornsey Lane crosses this cutting, on a noble bridge, which is called the Highgate Arch. The late Mr. Robert Stephenson, M.P., in his address to the Institution of Civil Engineers, on his election as President in January 1856, stated, that “tunnels for railways had traversed hills and penetrated mountains to the extent of nearly 70 miles,” the miles of railways opened in the United Kingdom at that time being 8,054.