Litchfield enquirer., 1870-12-08
MONT GEMS TUNNEL.

# MONT GEMS TUNNEL. a1"
 We clip, from the N. '. Evening Post tie
 following description of the greatest ''tun'
 nel" in the world. now rapidly approaching
 completion :- ss... ssat
 It is evident that for long time te l come the tunnel through the Alps neal
 Mont Cenis pass is likely to snpersede all ! other roads, and convey a vast number oi
 passengers and goods through, instead of | across, the great natural barrier which the l Alps present between Northern and South
 ern Europe. Much has been recently said
 about other Alpine tunnels, but none has
 been seriously undertaken; nor in the present state of political affairs in Europe,
 is any likely to commence for some time to
 come. Meanwhile the work We are refer 1 ring to is on the very point of completion. { all the possible or real difficulties having
 been avoided or overcome; and it may be
 predicted with confidence approaching to ] certainty. that the present year will wit
 ness the actual piercing of tine mountain, and the opening of 8 way between the val
 leys that carry water to the Gulf of Lyons and those that drain into the Adriatic.
 The reader who has followed the official re- turns of the progress of the tunnel, may think that, as there still remains nearly half mile to bore through, this statement IS premature, and that accidents and de- lays may still occur. No doubt, if by any sad complexity of political affairs, the war that is now raging should involve Italy as we'll as the Northern powers, the requisite human labor might cease to be available; but without such crisis there is no prob. ability of interruptions. Provided only that the machinery. which has been so welt tried, and which is now in admirable work ing order, should continue to hold out an other six months. there cannot be much doubt that the two ends will meet. One more year will perhaps be sufficient to complete not only the tunnel but the ap- breaches, and connect the lines of France and Italy by continuous rail little liable to interruption. .sf.+. ......e.
 The letter from which the Post quotes was written in July last. ssse : . E. THE TUNNEL. e
 A recent visit to the immediate neigh borhood of the tunnel, and to the resident engineers at both ends, and study of the collections of rocks that have been made during the progress of the works, has ena- bled me to appreciate fully this state of certainty as to the further progress and completion of the work, and also the causes of tLe difference in progress at the two ends. What may be called the physical history of the tunnel, as distin guished from it's history as work of en- glneering and mechanics, is now nearly complete, and possesses considerable in- terest.
 The great tunnel of the Alps passes under Mont Frejus,' about sixteen miles west of Mont Cenis and the pass known by that name. It is therefore incorrectly termed the Mont Cenis tunnel. It cuts through the waterhed of the Rhone aud the Pc, which in this part of the Alps is 8 crest varying from seven to ten thousand feet above tue sea. Mont Tabor, the high est of the crest, is few miles to the west of the tunnel, and is 10. 48O feet above the sea, while the Mont Cenis pass, the lowest point, Is about the same distance to the east, and is 6,930 feet above the sea. The height of the observatory on the summit of the ridge over the tunnel is 9,697 feet. The levels of the valleys to the north and south of this crest, or watershed, are re spectively, 3,612 and 1880 feet. This dlf- ference of level, upwards of 750 feet, by which the valley on the south, or Italian side, exceeds the northern or French side, would seem at first sight, to offer some diff faculties in constructing the tunnel. espe- cially if much water had been met with. By taking advantage, however, of the form of the valley, the railway will be carried by zigzag on the mountain side to some hundred feet higher level before entering the mountain on the French side, reaching the entrance of the tunnel at 4.O46 feet. There thus remains g difference of 334 feet, which, when distributed over seven and half miles, is found to be equivalent to gradient of A feet in Il mile, or one in 20.
 The tunnel has not been in course of actual construction more than twelve years, but 1t had been suggested as long ago as in l641. in pamphlet published at Lyons by SiRnor Medail, of Bardonecne. This pamphlet was brought under the notice of Charles Albert, at that time king of Sar- dinia, in whose dominions were included the whole valley of the Arc, as we'll as both sides of the mountain crest The work was thus from the first exclusively Italian, and France only became interested it it when it took possession of Savoy. The work has been carried on throughout from both sides by Italian engineers, according to the terms of the treaty by which Savoy was ceded to France. The King referred the matter to the Minister of the Interior to make due inquiries, and the engineer ing and physical questions involved were submitted to the consideration and judg- ment of M. Maus, Belgian, who was en- gineer.in-chief of the Turin and Genoa Railway, then in course of construction, and Professor Sismonda. a very eminent geologist, employed in the preparation of a geological map of Sardinia, since pub- lished. These two gentlemen. after visit ing and carefully examining the whole of
 the chain between Mont Cenis and Monte
 Genevra, reported favorably of the line se-
 lected by M. Medail. which was ultimately adopted. The matter then went into the
 hands of other engineers {who have now
 undertaken the work for the government,
 but as on further investigation and calcn-
 lation, based on the rate of progress of
 similar works already undertaken, it was
 estimated that at least thirty five years would be required for. the tunelling, even 1 if no unexpected difficulties or accidents supervened, it was natural enough that the
 government'should pause before deciding
 on work of such magnitude entirely for
 the benefit of q futnre generation. Then
 came the question whether by some me-
 chanical contrivance it might not be pos.
 sible to accelerate the progress. It was NA Al