the expense of the whole of the machinery and of the exterior works. This amount does not seem extravagant when we remember that for every yard of advance, never less—and frequently more—than seventy cubic yards of rock have to be excavated, and to be carried away (at the present time) a distance of three miles; that about twenty-five cubic yards of masonry have to be built, the stone for which is conveyed twelve miles in a mountainous country; that all the machinery employed has been constructed and invented expressly for the tunnel, and that the creation of two small towns has been necessary. The strata which have been pierced agree very satisfactorily in their nature and in their thickness with the indications of the geologists.[1] The engineers therefore believe that no greater difficulties will be encountered than those which have been overcome. Remarkably little water has been met with: the miner's dreaded enemy seems to have fled before the engineer who has utilised its power. I have not entered into a description of the manner in which this has been accomplished, because it has been frequently done before; but there is nothing more interesting in regard to the tunnel than
- ↑ Table of the strata which have been pierced on the French side of the great tunnel of the Alps:—
Mètres Mètres Thickness of the
Strata in Metres.1. Débris and pebbles from 0 to 128 128 2. Anthracitic schists " 128 " 2095 .35 1967 .35 3. Quartzite " 2095 .35 " 2476 .75 381 .40 4. Anhydrite " 2476 .75 " 2696 .90 220 .15 5. Compact calcareous rock " 2696 .90 " 2780 .20 34 6. Talcose schists " 2730 .90 " 2780 .20 49 .30 7. Compact calcareous rock " 2780 .20 " 2802 .02 21 .82 8. Anhydrite " 2802 .02 " 2831 .75 29 .73 9. Compact calcareous rock " 2831 .75 " 2852 .95 21 .20 10. Anhydrite " 2852 .95 " 2867 .15 14 .20 11. Calcareous schists " 2867 .15 " 3264 396 .85 12. Anhydrite " 3264 " 3334 .45 70 .45 11. Calcareous schist (the same as at Berdonnêche) " 3334 .45 " continues ? On the Berdonnêche side the tunnel passes through schist alone.
