. Bulletin - United States National Museum. Science. Figure 37.—The giant Roots lobe-type blower used for propelling the car. air sufficiently above atmospheric pressure to prevent the water from entering and to support the earth. In this, and his description of air locks for passage of men and materials between the atmosphere and the pres- surized area, Cochrane fully outlined the essential features of pneumatic excavation as developed since. In 1839, a French engineer first used the system in sinking a mine shaft through a watery stratum. From then on, the sinking of shafts, and somewhat lat
. Bulletin - United States National Museum. Science. Figure 37.—The giant Roots lobe-type blower used for propelling the car. air sufficiently above atmospheric pressure to prevent the water from entering and to support the earth. In this, and his description of air locks for passage of men and materials between the atmosphere and the pres- surized area, Cochrane fully outlined the essential features of pneumatic excavation as developed since. In 1839, a French engineer first used the system in sinking a mine shaft through a watery stratum. From then on, the sinking of shafts, and somewhat later the construction of bridge pier foundations, by the pneu- matic method became almost commonplace engineer- ing practice in Europe and America. Not until 1879 however, was the system tried in tunneling work, and then, as with the shield ten years earlier, almost simultaneously here and abroad. The first appli- cation was in a small river tunnel in Antwerp, only 5 feet in height. This project was successfully com- pleted relying on compressed air alone to support the earth, no shield being used. The importance of the work cannot be considered great due to its lack of Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States National Museum; Smithsonian Institution; United States. Dept. of the Interior. Washington : Smithsonian Institution Press, [etc. ]; for sale by the Supt. of Docs. , U. S. Govt Print. Off.
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