624 



THE GREAT ALPINE TUNNELS. 



THE ST. GOTHARD TUNNEL. 



This, which is at present the longest railway tunnel in the world, is 

 9.3 miles in length, and constitutes the summit of the "Gothard 

 bahn" — that is, the railway which runs from Lucerne to Chiasso on 

 the Italian frontier. There are about 100 tunnels in all, most of which 

 are for double line of way, the permanent wa}^ being very heavy, the 

 rails weighing 10<) pounds to the yard. 



The altitude of the tunnel at its north portal is 3,639 feet, and at its 

 south portal 3,757 feet above the sea. A gallery of direction was 

 driven throughout, and the gradient of the I'ails is only such as to pro- 

 vide for efficient drainage, viz., 5.82 per 1,000, or about 1 in 172. 



The following table may be of interest, giving the result of investi- 

 gations as to the cooling of the rocks: 



TEMPERATURE OF THE ROCK IN THE ST. GOTHARD TUNNEL. 



[Degrees are centigrade.] 



Date. 



April and May, 1880, the year when the ttin 



nel was pierced 



June, 1882 



July, 1883 



7.3 kilo, from the north 

 portal. 



Temper- 

 ature. 



30. 46 

 23. 73 

 22.20 



Lowering. 



Succes- 

 sive. 



6.73 

 1.53 



Total. 



7.05 kilo, from the*outh 

 portal. 



Temper- 

 ature. 



30.53 

 23. 39 

 23.1 



Lowering. 



Succes- 

 sive. 



7.14 

 0.29 



Total. 



7.43 



Although the works were carried on with energy, and with all the 

 best appliances then known, the time occupied was ten years; but the 

 most serious feature of the work was the heavy mortalit}^ among the 

 men. No less than 600 deaths occurred, including those of both the 

 engineer and contractor. 



From the experience then gained great improvements have been 

 introduced into the works of the Simplon, as will be described later 

 on; but the heavy loss of life in the St. Gothard was due to insufficient 

 ventilation, the high temperature, the exposure of the men to the 

 Alpine climate after emerging from the tunnel, the want of care as to 

 the changing of the men's wet mining clothes, and the poor character 

 of he food with which the men supplied themselves. All this has 

 been greatly ameliorated, and even in English tunnels certain improve- 

 ments have been introduced which were brought from Switzerland. 



The traffic through the tunnel has so largely increased that the ques- 

 tion of ventilation became of pressing impor ance, and the system of 

 Signor Saccardo, the well-known Government inspector of railwa3's 

 and engineer of Bologna, has been installed, which is an ingenious 



