=The Simplon Tunnel.=--The following facts are taken from a brief account of this great engineering feat in the Engineering Magazine: There is at present no direct rail connection between western Switzerland and Italy, and to reach Milan it has been necessary to go around to Lucerne and so on through by the St. Gothard route. The distance by rail from Milan to Calais by the Mont Cenis is 665 miles, and by the St. Gothard 680 miles. The distance by way of the Simplon Tunnel will be only 585 miles. The Jura-Simplon Railway from Geneva around the lake and up the Rhone Valley ascends to Brieg at an altitude of about 2,300 feet, while on the Italian side the railway from Milan stops at Domodossola, at an altitude of 900 feet. Between the two, which are 41 miles apart and over an elevation of 6,590 feet, lies the famous Simplon Pass. Connection is now made by diligence, the trip occupying a whole day. The plan of the new railway includes the prolongation of the present line on the Italian side to Iselle, at an altitude of about 2,100 feet, where the Italian entrance to the tunnel was begun in August, 1898. On the Swiss side the entrance is at Brieg, and the tunnel will connect these two towns, being 12.26 miles long. This is nearly three miles longer than the St. Gothard, but the altitude is only 2,300 feet above the sea, instead of 3,800 feet, as at the St. Gothard. The tunnel is to be straight laterally, but higher in the middle than at either end, the grade being 1 in 143 on the Italian and 1 in 500 on the Swiss side. The principal difference between the Simplon Tunnel and those previously pierced through the Alps is that, instead of one single tunnel, two separate tunnels, fifty-five feet apart, are to be constructed, connected by lateral passageways every 650 feet. At first but one of these is to be completed to the full dimensions, the other being carried through at only about a quarter of the ultimate cross-section, and not enlarged and put into use until the traffic demands it. Both tunnels are now being bored by the use of the Brandt hydraulic rotary drills, water being supplied at a pressure of 70 to 100 atmospheres. The borings are through gneiss, limestone, and slate. Holes two inches and three quarters in diameter and four or five feet deep are bored and the rock dislodged by means of dynamite. A narrow-gauge railway is used to remove the _débris_. It is expected that the tunnel will be completed in five years and a half. At the close of 1898, 300 feet had been penetrated on the south side and 1,300 on the north. The estimated cost of the complete double-track tunnels is 69,000,000 francs. This does not include the construction of the permanent way. The Mont Cenis Tunnel cost 75,000,000 francs, and the St. Gothard 59,750,000 francs. The work is practically controlled by the Jura-Simplon Railway. * * * * *