The Mersey Tunnel was lately opened by the Prince of Wales, and, as the London _Standard_ says, after an infancy of troubles and failures, and a ten years' middle age of inaction, the Mersey Tunnel emerges into notoriety under the hands of Mr. James Brunlees and Mr. C.D. Fox, and of Mr. Waddell, the contractor, as a triumph of engineering skill. The tunnel is 1,250 yards in length. It is driven through solid, but porous, red sandstone, through which the water has percolated in volumes during construction, at a level of about 30 feet below the bed of the river. It is lined throughout with blue bricks, the brickwork of the invert being 3 feet in thickness. Its transverse section is a depressed oval 26 feet in width and 21 feet in height, and it contains two lines of railway. At a depth of about 18 feet below the main tunnel there is a continuous drainage culvert 7 feet in diameter, entered at intervals by staple shafts. There are two capacious underground terminal stations 400 feet long, 50 feet broad, and 38 feet high, and gigantic lifts for raising 240 passengers in forty seconds, from more than three times the depth of the Metropolitan Railway to the busy streets above. These splendid lifts, the finest in the world, are now, through the engineering skill of Messrs. Easton & Anderson, like the tunnel, accomplished facts; and their construction and working were tested and reported on in high terms of favor by the Government Inspector, General Hutchinson, a few weeks ago. At the Liverpool end the direct descent to the underground platform of the Mersey Railway is about 90 feet; at the Birkenhead end the depth is something more.