weight of snow that may fall or drift upon them. By means of them the line will be kept quite free from snow exactly at those points where, without them, its greatest accumulations would have taken place. They are obviously only required high up the pass—the first, on the French side, of 450 metres long, will be at a very exposed angle of the road, about 400 feet from the summit. At and about the apex of the pass the covered ways will be about 5,000 metres, or a little more than 3 miles in length, not exactly continuous, but very nearly so. Upon the greater part of the plateau which extends along the Cenis Lake and nearly to _les Echelles_, covering will be unnecessary, the effect of the wind being to sweep the plain comparatively clear of snow, which becomes deposited in the angles of the hills that form the somewhat distant background of the panorama. Proceeding downwards on the Italian side, there will be the 1,200 metres of covered way on the old road parallel to _les Echelles_, already mentioned, and about 1,200 metres more farther down, freedom from serious snow-drifts not being obtained on the Italian side of the mountain until at an elevation of about 4,000 feet above sea level. That point passed, the softness and glow of the Italian climate become perceptible, not only by one’s own sensations, but because we witness the effects of the atmosphere from the crops and trees that surround us. The line of demarcation, beyond which cereals will not grow, is higher on the southern than on the northern aspect; suddenly we come upon the walnut and the sweet chesnut, and we have not proceeded more than a mile or so, when a turn of the road near to Mollaretta, 3,795 feet above the level of the sea, brings us upon the grape, growing in beautiful festoons, and yielding fruit that is said to make good and vigorous wine. But the highest point at which the vine can be cultivated on the French side of the pass—and that not always successfully, for in cold seasons the crops do not come to complete maturity—is St. Michel. Yet St. Michel is only 2,493 feet above the level of the sea, or 1,300 feet lower than Mollaretta. The total length during which the trains of the Mont Cenis Railway will not be “_en plein air_,” will be 11,113 metres, about 6¾ miles, scattered over 18 miles of distance, but in no case will the light of heaven be shut out, as both in the galleries and in the covered ways there will be openings for its admission, as well as for that of air, which openings can, however, be closed if the direction of drifting snow be towards them. As the average length of the eight tunnels is only 70 yards, it is obvious that the maximum of darkness in them, while the sun is above the horizon, will be twilight.