Oakley ” 800 Bishopton Glasgow and South-Western 760 Coates Park Midland 740 Buckhorn Weston Salisbury and Yeovil 739 Belmont Chester and Holyhead 737 Penmaen Bach Chester and Holyhead 721 Tottenham Great Northern 714 Leeds North-Eastern 700 Copenhagen Great Northern 694 Dover Chatham and Dover 682 Manton Midland 660 Ampthill ” 640 Chivet ” 620 Martello South-Eastern 616 Barnet Great Norther 605 Chelsfield South Eastern 600 (A) Followed by an open cutting of 100 yards; then a tunnel of 440 yards. The gradient in these tunnels is 1 in 70. For full details respecting them, see Paper read by Mr. Charles Nixon at the Institution of Civil Engineers. _Proceedings_, volume for 1842. Some of our tunnels have been extremely costly, the Kilsby, for instance, £125 per yard forward, total £302,000. The face of the Primrose Hill Tunnel at its London end cost £7,000, thereby adding to its total cost at the rate of £5. 15s. a yard. Up to 1857, the average cost of all tunnels was £102 per yard, or for 70 miles £12,320,000. Tunnels have certainly been constructed more cheaply since then.[129] Mr. J. G. Fraser assumes them to have cost at the average rate of £45 per lineal yard, but this must be considerably below the mark, notwithstanding that many of the more recently constructed tunnels have only been for “single line.” The dimensions of these tunnels on the 4 feet 8½-inch gauge, are usually as follows:—12 feet wide at rail level, 17 feet from rail level to soffit, whilst for a double line of the same gauge tunnels are usually about 25 feet wide at rail level, and about 22 feet from rail level to soffit. On the exceptional Great Western gauge, they would be respectively about a fourth higher and a third wider. We must only touch the Thames Tunnel at a tangent. Its length is 1,200 feet with two arches each 13 feet 9 inches at the springing of the arch; 16 feet 4 inches high from the invert. It cost £1,000 a yard, or for 400 yards £400,000, two and a-half times as much per yard forward as the most expensive estimate for the Mont Cenis Tunnel, more than three times as much as its cost per yard forward up to the present time. In addition, the approaches of the Thames Tunnel (for foot passengers only) cost £54,714, total £454,714. It is now about to be utilised as a railway tunnel, having been purchased by the East London Railway Company for the purpose of bringing together the lines at the north-eastern and south-eastern ends of London.