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The new overland route to India and the railway tunnel of the Alps: transverse section of the tunnel, 1869. Diagram of part of the Grand Tunnel under the Alps...The Sardinian Government appointed M. Maus, a Belgian engineer, and M. Sismonda, a geologist, to devise the best line of tunnel and the best mode of construction...three young men-Sommeiller, Grattoni and Grandis...hoped to contrive a more economical system by employing water-power, instead of steam-power, to condense the air...having become acquainted with Mr. Bartlett's use of the airforce to pierce holes in rocks, they perceived that the combination of water-power with that striking and boring power would be just the agent wanted for the tunnel-work...The arch of the tunnel is nearly semicircular; it is 25 ft. 3½ in. wide at the base, 26 ft. 2¾ in. at the broadest part, and 24 ft. 7 in. high at the Modane end, but 11¾in. higher at the Bardonneche end. Its roof and walls are cased with masonry; at the Bardonneche end the vault is of brick and the sides are of stone, but at the Savoy end the whole is built of stone...the water is carried off by a covered drain in the middle of the floor'. From "Illustrated London News", 1869. Creator: Unknown. (Photo by The Print Collector/Heritage Images via Getty Images)