96 TUN N ELI NO 



way. There are 2,000 of these cords, spaced 1 ft. 6 ins. apart, 

 one to each man. The engineers and foremen are more priv- 

 ileged, being provided with dressing-rooms and baths, partitioned 

 off from the two main halls. An extensive clothes washing 

 and drying plant has been laid down, and also a large restau- 

 rant and canteen. At Iselle, a magazine holding 2,200 Ibs. of 

 dynamite is surrounded and divided into two separate parts by 

 earth-banks, 16 ft high. The two wooden houses, in which 

 the explosive is stored, are warmed by hot- water pipes to a 

 temperature between 61 F. and 77 F., and are watched by 

 a military patrol; but at Brigue a dynamite manufactory, 

 started by an enterprising company at the tiir.e of the com- 

 mencement of the works, supplies this commodity at frequent 

 intervals, thereby avoiding the necessity of storing in such 

 large quantities. This dynamite factory has been largely in- 

 creased, and supplies dynamite to nearly all the mining and 

 tunneling enterprises in Switzerland. 



Geological Conditions. Before the Simplon tunnel was au- 

 thorized, expert evidence was taken as to the feasibility of 

 the project. The forecasts of the three engineers chosen, 

 in reference to the rock to be encountered and its probable 

 temperature, have, as far as the galleries have gone (an ag- 

 gregate distance of nearly 2 miles), generally been found 

 correct. At the north end, a dark argillaceous schist veined 

 with quartz was met with, and from time to time beds of 

 gypsum and dolomite have been traversed, the dip of the 

 strata being on the whole favorable to progress, though timber- 

 ing is resorted to at dangerous places. Water was plentiful 

 at the commencement; in fact, one inrush has not been stopped, 

 and is still flowing down the heading. The total quantity of 

 water flowing from the tunnel mouth is 16 gallons per second. 

 of which 2 gallons per second are accounted for by the drilling 

 machines. At Iselle, however, a very hard antigorio gneiss 

 obtains, and is likely to extend for 4 miles. Very dry and 

 very compact, it requires no timbering, and presents no great 



