TL'NNELS TliltofUH HABD ItOCK 95 



of the tunnel commences, and extends for 12 miles. The line 

 then curves to the left with a radius of 1,311 ft before emerging 

 on the left hank of the Diveria. Commencing at the northern 

 entrance, a gradient of 1 in 500 (the minimum for efficient 

 drainage) rises for a length of 5j miles to a level length of 

 550 yards in the center, and then a gradient of 1 in 143 de- 

 scends to the Italian side. On the way to Douio d'Ossola one 

 helical tunnel will be necessary, as has been carried out on the 

 St. Gotliard. There will be eventually two parallel tunnels, 

 having their centers 56 ft apart, each carrying one line of way; 

 but at the present time only one heading, that known as No. 1, 

 is being excavated to full size, No. 2 being left, masonry lined 

 \\ here necessary, for future developments. By means of cross 

 headings every 220 yds. the problems of transport and ventila- 

 tion are greatly facilitated, as will be seen later. As both 

 entrances are on curves, a small "gallery of direction" is 

 necessary, to allow corrections of alinement to be made direct 

 from the two observatories on the axis of the tunnel. 



The outside installations are as nearly in duplicate as cir- 

 cumstances will allow, and consist of the necessary ofliivs. 

 workshops, engine-sheds, power-houses, smithies, and the nu- 

 merous buildings entailed by an important engineering scheme. 

 Great care is taken that the miners and men working in the 

 tunnel shall not suffer from the sudden change from the warm 

 headings to the cold Alpine air outside ; and for this purpose 

 a large building is in course of erection, where they will IH? 

 able to take off their damp working clothes, have a hot and 

 cold douche, put on a warm dry suit, and obtain refreshments 

 at a moderate cost Injfoiv returning to their homes. Instead 

 of i-;ich man having a locker in which to stow his clothes, A 

 perfect forest of cords hangs down from the wooden ceiling, 

 _'" ft. above floor-level, each cord passing over its own pulleys 

 and down the wall to a nuinlwivcl bt-laying-pin. Each cord 

 supports three hooks and a soa]>-dish, which, when loaded with 

 their owner's property, arc hauled up to the ceiling out of the 



