The Great Bridge Read Online Free PDF Page A

been struck at ninety-six feet. But below a depth of fifty to sixty feet, the material had been so very compact that the borehole had remained open for weeks without the customary tubing. So it was his judgment that there would be no need to go all the way to rock. A depth of fifty feet on the Brooklyn side ought to suffice and the whole operation would probably take a year.
    About the prospects on the New York side, he was rather vague—but it looked, he said, as though bedrock was at 106 feet and there was a great deal of sand on the way down. Still there was a chance that rock might be found closer to the surface. An old well near Trinity Church showed gneiss at twenty-six feet, he noted, and in the well at City Hall the same rock was found at ninety feet. “The whole of Manhattan Island appears to rest upon a gneiss and granite formation,” he said. The greatest depth to which similar caissons had been sunk before this was eighty-five feet. But he was willing to take his to a depth of 110 feet if that was what had to be done. His consultants said they did not think he would find that necessary.
    Presently they took up the question of the timber foundations and their fate, once he left them buried forever beneath the towers, beneath the river, the rock, sand and muck of the riverbed. In his report, Roebling had explained at some length how the caissons would be packed with concrete once they were sunk to the desired position, and why, in their final resting place, well below the level where water or sea worms could reach them, they would last forever. But there were some among the consultants who wished to hear more on the subject and who had a number of questions.
    That particular session on the foundations had taken place on March 9. Two days later, on the 11th, it was announced that the renowned engineers had approved the Roebling plan, “in every important particular.” Their official report would come later, but in the meantime the public could rest assured that the plan was “entirely practicable.”
    Only Congressional authorization was needed now, since Congress had jurisdiction over all navigable waters and the bridge was to be a post road. Unlike the government in Albany, or those in either city, the government in Washington had some regulations it wished to see adhered to. Congressional legislation already drawn up stipulated that the bridge must in no way “obstruct, impair, or injuriously modify” navigation on the river. In particular, there was concern in Washington that it might interfere with traffic to and from the Navy Yard, and to be certain that every detail of the plan was fully understood, General A. A. Humphreys, Chief of the Army Engineers, decided to appoint his own review panel to give an opinion on it, irrespective of the conclusions reached by Roebling’s consultants (This was to be the only public scrutiny of the design or the location.) So at about that point it had seemed the most sensible next step would be for everyone to go take a look at some of Roebling’s existing works to see how he had previously handled somewhat analogous situations. Let his work speak for itself, he had decided.
    The tour was arranged almost overnight and if there was any initial intention to restrict it to a relatively small body of professionals that idea was speedily overruled. A total of twenty-one gentlemen and one lady made up the “Bridge Party,” as it was referred to in subsequent accounts. In addition to the two Roeblings, the seven consultants, and three Army engineers—General Horatio Wright, General John Newton, and Major W. R. King—several prominent Brooklyn businessmen were invited, most of whom were or were about to become stockholders in the New York Bridge Company. A Brooklyn Congressman named Slocum—General Henry W. Slocum—was included, as were Hugh McLaughlin, the Democratic “Boss” of Brooklyn, and William C. Kingsley, Brooklyn’s leading contractor, who was known to be