Discoveries and inventions of the nineteenth century (1905)
Routledge, Robert · London : G. Routledge and Sons · leaf 428
Fig. i^Tc—The Bridges over the Maienreuss near IVasen, 378 ROCK BORING. … Fig. i%Td.—Windings of the Line near Wascn. ROCK BORING. 379 corkscrew ; it is one of a series of helicoidal tunnels of which there areseveral examples on the line. The entrance to this tunnel is 2,539 feet, theexit 2,654 feet, above the sea level. It is known as Pfaffensprung{y\.oxi\C%Leap)…
Inventions
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