April 22, 1880] 



NATURE 



585 



the top of the tunnel. To open this boring, six perforat- 

 ing machines were arranged on a cast-iron stand placed 

 on rails. These machines, first of all, perforated six 

 holes in a horizontal direction. Then shifting the points, 

 they made six new holes, and again a third set and a 

 fourth set. This ought to have produced twenty-four 

 perforations ; but as there was always some delay from 

 the change of drills or other hindrances, they seldom had 

 more than eighteen or twenty. As the tools striking on 

 the rock became very hot, and much dust was produced 

 in the holes, they required to be constantly moistened by 

 a jet of water. The water was carried on a train behind 

 the cast-iron stand, and, by means of an india-rubber pipe 

 to convey compressed air, was projected forcibly in several 

 jets. 



The holes bored were generally 1 m. deep. When the 

 face of the rock was. in the opinion of the head miner, 

 sufficiently perforated, the stand was drawn back and 

 the holes were charged with a mixture of dynamite and 

 clay. Then they were fired by means of slow matches, 

 so arranged that the central holes should explode before 

 the others. After that they broke the large fragments, 

 loaded trucks with the rubbish, and rolled them towards 

 the opening ; and thus the gallery was advanced about 

 i m. Then placing rails in front, the stand with 

 its boring-machine was brought back, and the mining 

 recommenced. 



The advance was more or less difficult according to 

 the nature of the rocks, but on the whole the contractor 

 was fortunate in [Uiis respect. The rock was hard, but 

 its hardness was almost always suitable for perforation. 

 About three-quarters of an hour were necessary to make 

 a hole 1 metre deep ; and under favourable circum- 

 stances four operations would be made in twenty-four 

 hours, that is to say, an advance of 4 metres on each side. 

 The most favourable rocks were granite, gneiss, mica 

 gneiss, and mica schist. The layers, which were almost 

 vertical, lay from east to west, and were therefore at right 

 angles to the direction of boring. There were, however, 

 three unfavourable circumstances which greatly hindered 

 the works at certain times : — (1) The infiltrations of water 

 in the Airolo tunnel during the first months of the opera- 

 tions, and in such quantities that a regular river flowed 

 from the southern opening. Fortunately dynamite is not 

 affected by water, and after boring several hundred metres 

 the infiltration stopped. (2) Rocks of exceptional hard- 

 ness were met with from time to time blunting the best 

 drills, and scarcely an advance of 1 metre a day could be 

 made. (3) In the Goeschenen gallery, at 2,700 m. from the 

 mouth, they came upon a bed of rock entirelydisaggregated, 

 where they could only work with the pickaxe and were afraid 

 of being buried. Under the enormous pressure of the 

 mountain the props were crushed, and even the arches of 

 masonry overthrown. At this part the advance was from 

 30 to 40 m. a month, and it continued for more than four 

 months. There was some danger even of the rock falling 

 behind where the workmen were engaged, and so isolating 

 them and all who were beyond. In order to strengthen 

 this dangerous part it was necessary to employ a special 

 system of arches strengthened with iron. 



When the advanced boring was completed, it was 

 enlarged on the right and left. After that was done, they 

 proceeded to build the arches of the roof, and then dug 



to the level of the tunnel's base a trench of about 3 m. wide, 

 called the Cunette de Strosse. It is not dug in the middle, 

 so as to leave as long as possible the way clear on the 

 higher level. Then all is removed that remains on the 

 right and left of the trench, and which is known as Strosse. 



These different excavations are almost all done by 

 perforations, and the holes being bored downwards, the 

 work is more easy, whether for boring or exploding. 



The transport of rubbish and materials had to be per- 

 formed as often as possible by more powerful agents than 

 manual power or horse-power. Steam-engines were out 

 of the question, the air being already vitiated by the 

 constant percussion of the boring-drills. The com- 

 pressed air was employed to move the locomotives, just 

 as if they were acted upon by steam. It was collected in 

 reservoirs placed on the locomotive trains, and by simply 

 turning a cock the machine was moved or stopped. But 

 as the air of the atmosphere did not furnish a " course " 

 sufficient, except by means of enormous reservoirs, they 

 constituted "compressors" of the same system as those 

 already in use, but which compressed the air to fourteen 

 atmospheres. With so considerable power the locomotives 

 were sufficiently supplied by ordinary reservoirs. 



Charge of the works was handed over to the contractor, 

 M. Favre, in October, 1S72, on condition of completing 

 them within eight years ; should they occupy nine years 

 a heavy penalty was attached. On February 29, 1880 

 the two advanced borings met with great accuracy. By 

 a mistake the general direction only was taken, and 

 therefore the exact amount of error was not ascertained 

 but it could not have exceeded 10 centimetres (or less 

 than 4 inches) ! This meeting did not take place in the 

 middle of the tunnel, but at a point about 600 m. nearer 

 Airolo than Goeschenen. The newspapers fully reported 

 the event, the joy of which was greatly mingled with 

 sorrow on account of the death of Louis Favre, the 

 energetic and intelligent contractor, who was to have pre- 

 sided at the ceremony, after having organised and directed 

 all the details, and at the very moment when he was 

 about to realise the aim of his efforts. He died 

 suddenly in the tunnel, the offspring of his labours, on 

 July 19, 1879. Born in 1826 in Chene, near Geneva, he 

 left his native place as a journeyman carpenter, and by 

 his intelligence and talent returned to Switzerland thirty 

 years afterwards to be intrusted with the greatest under- 

 taking of the present time. As he had thoroughly well 

 organised everything, the works were continued without 

 him, and also completed ; but when shall we find such 

 another man to begin again such another undertaking ? 



There is still much to do in the tunnel — rocks to clear 

 away, mason-work to be built, &c. — but now the ground 

 is known, and there is no fear of being able to complete 

 the tunnel within the stipulated time. But what purpose 

 would it serve ? The lines of approach could only be 

 finished long after the tunnel, being much less advanced. 

 It is proposed, however, to have carriages running next 

 winter between Goeschenen and Airolo, driven by atmo- 

 spheric locomotives. That would no doubt be an advan- 

 tage, but would the result be worth the great exertions 

 necessary ? 



Much has been said of the extreme heat which prevails 

 in the tunnel, and there is no doubt it is almost intoler- 

 able, being 32° to 35 C, and is injurious to men, and 



