The Hauenstein Tunnel in Switzerland, one mile and an eighth in length, was from four to five years in being constructed. Two shafts were sunk, one 417 feet, and the other 558 feet deep. Portions of the shafts and tunnel were lined with masonry on account of the water and sand, and varying firmness of the strata passed through, all of which caused many difficulties and delays. The progress made between the intervals of obstruction, varied from fifty-six to one hundred and nine feet per month on a face. The cost was about $400 per running yard. The Nerthe Tunnel in France, is nearly three miles in length. For nine hundred and fifty yards of its length it is in rock cutting, where arching was unnecessary. The remainder is lined with masonry. Twenty-four shafts were sunk, varying in depth from sixty-five to two hundred and sixty-two feet. The work was completed in three years, and cost $412 per running yard. The Tunnel of Rilly, on the line from Paris to Strasbourg, is a little more than two miles long. Eleven shafts were commenced, two of which were abandoned on account of the abundance of water, the others were completed. In some of the shafts the water was so troublesome that it was necessary to use for curbs cast iron cylinders, five feet in diameter, and about three feet long, bolted together. The time consumed in the construction of this tunnel was three years and four months. It passes through a chalk formation, which was, in some places, so seamy, that great precaution was necessary to prevent the falling in of large masses. The cost was $432 per running yard. Mr. Storrow visited and examined several other French tunnels, and his reports upon them are full of interest; but the abstracts given are sufficient to show the various obstacles and difficulties encountered by the English and French engineers in the prosecution of their work, as well as the cost, and the success which rewarded their skill and perseverance. We now come to the great tunnel under the Alps, the most remarkable and gigantic enterprise ever attempted in civil engineering. Our facts in regard to it are derived from Mr. Storrow's report, (which it will be remembered was made in November, 1862,) and from a very able account in the Edinburgh Review of July, 1865.