. 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 Figure 38.—Testing alignment of the Broadway Sulnvdx .11 niehl bv driving a jointed rod up to street level. {Scientifit American, March 5, 1870.) In 1871 Dewitt C. Haskin (1822-1900), a west coast mine and railroad builder, became interested in the pneumatic caissons then being used to found the river piers of Eads' Mississippi River bridge at St. Louis. In apparent total ignorance of the Coch- rane patent, he evolved a similar system for tunneling water-bearing media, and in 1873 proposed construc- tion of a tunnel through the silt beneath the Hudson to provide rail connection between Xew Jersey and New York City. It would be difficult to imagine a site more in need 232 BULLETIN 240: CONTRIBUTIONS FROM III1'. MUSEUM OF HISTORY AND TECHNOLOGY. Please note that these images are extracted from scanned pa
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