THE RAILWAY TUNNEL THROUGH THE ALPS, 
T HERE is at present a break in the railway system of 
communication between France and Italy, occasioned 
by no less an obstruction than the Alps. To pierce a passage 
through the Alps, and complete the line of communication 
between the opposite sides, is the object of the tunnel now in 
course of execution. This gigantic work, which will be, when 
completed, fully seven and a half miles in length, was sanc- 
tioned by the Sardinian Government in 1857, and although, in 
June, 1858, and September, 1859, arrangements were made 
for fixing perforating machinery, the work was not actually 
commenced till November, 1860. The railway from Genoa 
and Turin stops at Susa, and that from Lyons at St. Michael ; 
between these two termini, Mont Cenis intervenes. The northern 
entrance of the tunnel (A) is near the little hamlet of Fourneau, 
and less than half a mile from the small town of Modane. The 
southern end is in a deep valley at Bardonneche, on the Italian 
side of the Alps. 
The entrance to the tunnel on the side of France is 3,946 
feet above the level of the sea, and its termination on the 
Italian side 4,380 feet ; so that the actual difference of level 
between the two extremities of the tunnel is about 434 feet, 
the Italian end being thus much the highest. There are two 
gradients in the tunnel, which divide it nearly in two equal 
lengths, the ascending gradient from the side of France rising 
to 445 feet, from which point it gradually falls to the opposite 
end, on the side of Italy, to the amount of only about 10 
English feet, in a length of nearly 3f miles ; so that for this 
distance it may be considered to be practically level. 
The rising gradient ascends to the middle of the tunnel at 
the rate of 1 in 45. The descending one falls at the rate of 
1 in 2,000 ; so that one half of the tunnel has a tolerably stiff 
gradient, and the other quite easy; but for such an Alpine 
country the gradient of 1 in 45 is much better than might 
have been expected under the circumstances. 
It was, of course, necessary to prepare accurate plans and 
sections to determine the levels, fix the axis of the tunnel, and 
set it out on the mountain top ; to erect observatories and 
guiding signals, solid, substantial, ppd true, The mountains 
VOL. in. — no. x, M 
