A few years ago people could think or speak of nothing else for the Alps but tunnels; there was to be a tunnel railway through the Simplon, one through the St. Gothard, and as immediately to the eastward of the Great St. Gothard range, there is a rapid diminution of elevation of the Alpine mountain, no less than three passes were named as suitable for tunnels, the special advantage of each being that they could be constructed by means both of shaft and of adit. These three passes commencing near Dissentis, run from north to south, and each, as it were, starting from one root, branches off and follows its own course through its own system of valleys, but the three unite in a common pass about two miles to the south of Olivione. They are called respectively the Cristillina (the easternmost), the Greina (the centre), and the Lukmanier (the westernmost). The length of tunnel suggested for the Cristillina was the most modest of all, only seven miles; for the Greina it was to be twelve and a-half miles, whilst that for the Luckmanier was proposed to be fifteen miles, nearly but not quite double that now constructing under the Great Vallon Mountain. But if the tunnel of the Lukmanier was to be the longest, its advocates were able to assert in its favour, that not only could the shafts be numerous, but that not one of them need be at a greater depth from the surface than two hundred yards. Well, notwithstanding these supposed advantages, these long tunnel railways have ever since remained a dead letter, and have long ago been consigned to rest in the wide laying burial ground of Utopia. We shall one of these days (_probably_, in four or five years) have _one_ tunnel through the Alps; we are not likely in this or the succeeding generation to have a second. At a very early period in the history of English Railways, the ventilation of tunnels came to be considered a very important question, and as usual on such occasions, ignorance furnished an immense number of facts and realities which experience showed to be nothing but fictions. It was in deference to the highly wrought popular feeling on the subject, when every manner of evil was prognosticated for travellers going through tunnels, that the late Mr. R. Stephenson was induced to construct the large ventilating shafts on both the Kilsby and the Watford tunnels of the London and North-Western Railway. There are two shafts in each of these tunnels, the diameter of each of the four being sixty feet. They may be said to divide the tunnels into three distinct parts, the periods of going along each space of sixty feet being perfectly appreciable by the traveller. The ventilation is no doubt better in consequence of the execution of these gigantic shafts; but experience has long since shown that shafts nine to twelve feet in the clear, are quite sufficient for all ventilating purposes, no matter how much the tunnel may be below the earth’s surface.