Martin, the senior man among them, efficient, pleasant, colorless, was still serving as Roebling’s stand-in, supervising the work over-all. Collingwood, the Elmira jeweler whose initial intention had been to stay with the job only a month, was now assigned to completing the Brooklyn tower, while the inventive and reliable Paine had charge of the New York tower.
Once the Brooklyn tower was finished, Collingwood went across the river to take charge of the New York anchorage, that foursquare masonry pile, which, with its pair of deep arches, looked like the beginnings of a Roman bath. The anchorage was already as high as an eight-story building. It stood nine hundred feet inland from the New York tower and filled most of the block between Cherry and Water Streets. Four great cables descending from the tower would be secured to this mass on top, up near the end closest to the tower. The cables from the tower to the anchorage would carry what would be known as the land span of the bridge. They would be fixed to chains of huge iron bars that disappeared into the anchorage and were, in turn, tied to four great cast-iron anchor plates embedded deep within the granite, in the heel of the anchorage, as it were, down near the level of the street.
The dimensions of the New York anchorage and that of the one in Brooklyn were 119 by 129 feet at the base and 104 by 117 feet on top. For the time being the two structures stood just over eighty feet high, bristling on top with the same sort of timber derricks and other stone-hoisting apparatus used on the towers. Once the cables were finished, more stone would be added, taking the level up to that of the roadway, or to nearly ninety feet. The final total weight of each anchorage would be 120 million pounds, or sixty thousand tons.
Had either one of them been built someplace elsewhere, it would have been regarded as most imposing and awe-inspiring, in the way the Brooklyn tower had been when it loomed up all alone at a height of eighty feet. But standing in line with one of the towers, an anchorage did not look like much. The towers attracted all the attention, understandably. Still, in terms of the engineering involved, the anchorages were extremely interesting and their importance to the bridge was very great indeed.
Roebling wrote that there were but two factors to deal with in the anchorages—granite and gravity. The first he described as “a material whose very existence is a defiance to the ‘gnawing tooth of time’”; the second he called the only immutable law in nature; “hence, when I place a certain amount of dead weight, in the shape of granite, on the anchor plates, I know it will remain there beyond all contingencies.”*
The anchor plates—four to an anchorage, one for each cable—had been set in position during the early stages of the stonework. Their general shape, as Roebling said in his specifications, was that of an immense oval spider, 16 by 17.5 feet and 2.5 feet thick. They weighed 46,000 pounds, or twenty-three tons, apiece and just getting them into position properly had taken some doing.
The plates rested flat at the bottom of the stone mass, like mushroom-style ship anchors standing upright. Each of them had been cast with two parallel rows of nine oblong apertures into which eighteen of the iron eyebars were placed, set perfectly erect, making thereby two identical upright rows of nine bars each. The anchor bars, as they were called, stood twice as tall as a man and had an eye at each end. They had each been forged in a single piece, smooth, flat, and exactly like the others to be used in the same position—no easy trick at the time.
(Roebling had had to decide whether to use iron or steel for anchor bars. During his visit to the Krupp works at Essen, in 1867, the managers had forged an all-steel prototype for his inspection but could not guarantee the quality he wanted. So he settled on wrought iron. Several different mills produced the bars—the Keystone Bridge Company, the Edge Moor Iron Company, the Phoenix Iron Company—and as William Kingsley wrote, the finished products were considered “splendid specimens of what American manufacturers can do.”)
Below the underside of the anchor plate, through the nine eyes of each row, all matched in position as one, big steel pins were inserted and drawn up against the plate, fitting into semicylindrical grooves, and thereby forming the first link, a double-tiered link, of a gigantic double-tiered eyebar chain that extended up through the masonry in a gradual arc until it surfaced on top.
The anchor bars were of slightly different sizes, depending on their position in the chain, but they averaged twelve and a half feet in length, and in the first three links—those nearest the anchor plates, where the pull from the cables would be felt the least—they were seven inches wide and three inches thick, swelling enough toward the ends to compensate for eyeholes five to six inches in diameter. The bars of the fourth, fifth, and sixth “links,” however, were increased in thickness, to eight by three inches, and from there to the top, as the bars became horizontal and so came directly in line with the pull of the cable, they measured nine by three, except for the last link, where the number of bars was doubled and their width was halved. The last link had in all thirty-eight bars, in four tiers, to catch hold of the cable wires. Washington Roebling had spent months working out the entire arrangement.
The anchor bar chains had grown apace with the masonry. Once the anchor plates were fixed in position, the stone was built over them and close about the first set of anchor bars in each chain. Then the second set of bars was put in place, the eyes of the new eighteen fitting into those of the first eighteen, and heavy pins were put through all of them, making joints like two parallel door hinges. Each new set of bars after the first two was then made to incline forward, toward the tower, a little more than its predecessor, forming a steady curve, or arc, so adjusted as to bring the end of the chain out on top of the anchorage at exactly that point where the end of the cable would be coming in—which was about twenty-five feet back from the edge facing the tower. By the summer of 1876 the huge iron bars, painted with red lead to guard against rust, were protruding out of the upper surface of each anchorage, ready to take hold of the immense load of the cables and looking, as someone said, like the clutching fingers of a giant imprisoned within the stone.
Wilhelm Hildenbrand was to design the approaches leading to the two anchorages. This assignment in itself involved a series of structures nearly half a mile long, all told, and a total of nine different stone or iron girder bridges to span the intervening streets. The amount of work required for these structures alone was enormous, as Roebling explained to the Board of Trustees. *
The Brooklyn anchorage, begun in 1873 and finished two years later, was the responsibility of George McNulty, who by this time had also managed to grow an imposing handle-bar mustache. Though not yet thirty, McNulty was unquestionably one of the ablest men on the job. Roebling had assigned him to preparing hoists, drums, wheels, and other mechanical paraphernalia needed for cable making, all of which had to be made up exactly as Roebling wanted and mounted on top of the Brooklyn anchorage. As with nearly everything else about this bridge, the cables would originate in Brooklyn.
Since McNulty, along with each of the other assistant engineers, had had no previous experience building suspension bridges, every step after the stonework was a new one and there might have been costly delays or mistakes had it not been for Roebling’s extraordinary written communications and for Master Mechanic E. F. Farrington, the one and only man among them who had ever worked with wire before.
The cable-making machinery was to be essentially the same as what had been used at Cincinnati, which Farrington had helped set up under Roebling’s direction. Farrington was the one now who could train the men to do the all-important wire work out over the river, ship riggers many of them, but few of whom had ever before seen anything of this kind. Farrington had helped Hildenbrand do up a set of finished plans for the footbridge that was to swing from tower to tower and had built an amazing scale model according to Roebling’s directions. The model was set up in a big room at the Bridge Company, where the men could gather about it. The towers were of wood and stood about five feet high and fifteen feet apart and from them were suspended sm
all steel wires, miniature wheels, “cradles,” the footbridge, everything exactly as it would be. Each part of the model was marked with a tag, explaining its function, and everything worked as it would once the cable spinning began.
Farrington was, in fact, the single person on the job who could speak from experience about the work that lay ahead and who had the clearest idea of the problems there could be.
In the time since Roebling’s departure for Europe, the stonework had proceeded more or less as expected—slowly, gradually, stopping altogether during the winters. There had been a few brief, unexpected delays—because quarries failed to deliver on schedule and once because funds ran low—and there had been more accidents. But generally speaking the towers had gone up about as smoothly and efficiently as could have been hoped.
The stone came from some twenty different quarries and of the thousands of shiploads sent only one was lost. The stone was unloaded at the yard at Red Hook and from there came up to the bridge on big scows that tied up at the tower docks. Then one by one, as needed, individual blocks were picked out of the scows by derricks and placed on small flatcars that ran on rails laid in various directions around the foot of the tower. A couple of men would roll the block around to the back of the tower and from there it would be hoisted up onto the tower, but no longer by the fifty-foot boom derricks mounted on top. The elevation was too great for that now. Instead the system worked this way:
On top of each tower, in the center and projecting over the edge, were two huge iron pulleys, in line with which, and running the full height of the masonry, were heavy timbers, laid up like tracks, to take the chafe of the block as it made its ascent. A steel wire rope, an inch and a half in diameter, attached to the drum of a powerful steam hoisting engine on the ground, passed first through one pulley, then down to the ground, then up again, through the other pulley, and down to the drum of a second engine. To both of the vertical sections of this continuous rope, running up and down the side of the tower, were attached big hooks that engaged the iron eyebolts inserted in the ends of each granite block. The hooks were fastened, in other words, so that one set was coming down while the other went up, or so that raising one block lowered the hooks needed to lift the next block in line.
Sometimes, when a particularly heavy block was being hoisted, the vibrations on the ropes, caused by the straining pulsations of the engine, became so violent that the block would have to be lowered again and extra rigging attached to it. Only once, however, did a block shake loose and fall, from two hundred feet up, demolishing the tracks below and burying itself halfway in the ground.
As each stone got to the top of the tower, it passed between the rails of a track laid lengthwise along the edge on a timber superstructure. When the stone cleared the track, another flatcar was shoved under it and the stone was unhooked and moved quickly to where a boom derrick could pick it up and swing it into place. On the arches of the Brooklyn tower, the keystones, huge blocks weighing eleven tons, were fitted in without any trimming, just as they came from the quarry.
The top of a tower was an extremely busy, crowded place, with perhaps eighty men at a time working up there. Every man had to know just what he was about. A stiff breeze blew nearly all the time, it seemed, and in late fall or early spring it blew bitterly cold. One November a magazine editor who ventured no farther up the Brooklyn tower than the base of the great arches wrote that from the finished span “a prospect will be afforded which, for grandeur, will have no rival in the world,” but doubted there would ever be many sight-seers in wintertime.
Master Mechanic Farrington later wrote this memorable description of an early morning on top of the Brooklyn tower:
There are times when standing alone on this spot, one feels as completely isolated as if in a dungeon. Some three years ago I had an experience of this kind by daylight. It was in the early morning, when a dense fog covered the whole region, that having occasion to examine some machinery, I went on the tower before the time for commencing work. I shall never forget that morning. I found the fog had risen to within twenty feet of the top of the tower, and there it hung, dense, opaque, tangible. It was what you might seem to cut with a knife. It seemed that I might jump down and walk upon it unharmed. It looked like a dull ocean of lead-colored little billows; vast, dead, immovable.
The fog seemed to follow the conformation of the ground, rising to a certain height above it in all directions, and obscuring all below that line. The spires of Trinity in New York, and in Brooklyn, and the tops of the masts of a ship in one of the dry docks, with the roof of the bridge towers, were all that were visible of the world below. Here and there where the heat from the furnace chimneys rarefied the air, white cones would rise like boiling springs, and I could in one direction trace the cautious movement of a steamer by the same means. Rising through this misty veil was the confused crash and roar of busy life below.
By and by the heads of the workmen began to appear, as they clambered up the stairway…The fog lost its density. A thin vapor seemed to rise from it—a fog upon a fog—like a mist from the ocean, and the whole began to settle and to melt away. Spires, masts and chimneys began to appear; boats were seen dodging about like porpoises, just below the surface of the mist. By 10 o’clock the fog had disappeared, and travel, which had been seriously interrupted, was resumed.
Perhaps the biggest problem on top was making signals to the engineers in the yard below to prevent overwinding of the hoisting engines. Shouting seldom worked because of the wind. At times fog made flag signals impossible, and a system of signal bells that had been rigged up was constantly breaking down. Men looking out over the edge had to be prepared always for sudden gusts of wind that could throw them off balance.
Thus far three men had been killed in falls from the towers. The engineers told reporters later that every precaution had been taken against such accidents. Anyone who experienced the slightest giddiness on top was immediately ordered down again and assigned to ground work. But a protective railing of the sort critics of the work had been calling for would have been more trouble than it was worth, the engineers said.
In 1875 a man named Reed and another named McCann fell from the Brooklyn tower and were killed instantly. Reed, it appears, had been subject to epileptic fits, a fact he had concealed when he applied for a job. A man who had been working nearby claimed he heard Reed groan just before he fell.
McCann had been standing at the edge, on the corner of one of the buttresses, as a box of mortar was about to be raised by a derrick. Instead of walking around the right angle of the corner, he jumped across it. But at the same instant, the mortar box swung into the air and hit him, knocking him beyond the edge of the tower. He fell the distance.
And it had been just that May of 1876 that John Elliot fell from the New York tower. His job had been to shove the flatcar under the blocks as they arrived on top. His foot slipped and he went through the opening in the track. He struck a projecting beam on the way down and landed inside one of the arches.
But these had not been the only horrible deaths. A man named Cope, who had the duty of guiding the rope onto the drum of a hoisting engine, tried to kick the rope into place when it was not winding to suit him. He had been shown how to do the job properly, where to stand and so forth, but ignored what he had been told. He kicked and he missed his mark. The rope caught his foot and wound his leg around the drum. His leg was crushed so badly that he died almost immediately.
Another man was crushed by a block of granite that struck him in the stomach. One of the carpenters was killed by a falling stone. And a man at work somewhere near the base of the Brooklyn tower was rolling a wheelbarrow loaded with dirt across a plank at a fairly considerable elevation, when, by accident, the barrow ran off the edge of the plank. Instead of letting go, he held tight to the barrow handles, falling to his death.
But there had been numerous narrow escapes as well, and one in particular would be talked about for years to come. Near the completion of the Br
ooklyn tower a man named Frank Harris (not the one who attained literary notoriety) fell head over heels down into one of the hollow spaces between the three main shafts of the tower—a drop of 186 feet, according to later accounts. His companions, assuming he was dead, started down for the body. But then they heard Harris calling for somebody to lower a rope. He had landed on an empty cement barrel floating in about three feet of rain water that had collected in the pitch-dark stone well and he had received only minor injuries. Eight days later he was back at work on top of the tower.
By the time the towers were finished, the bridge had already taken the lives of a dozen men, but in the early summer of 1876, the engineers were telling reporters that from then on the work would get even more dangerous. It was the sort of statement to double public interest overnight.
Since the summer the bridge began, there had never been a time when the public was not interested in it. But things were different now, with the two gigantic towers facing each other from opposite shores. There was no longer any problem picturing the immense scale of the highway to be slung between them. Nor did it seem very likely now that anything could bring the work to a halt. In the spring of 1876 there had been a much publicized hue and cry from some of the shipping interests. It was claimed the bridge would obstruct traffic on the river. Public hearings had been held; several warehouse owners had spoken out vehemently, calling the bridge a “nuisance” and claiming it would “cramp the commerce” of the river port. But a shipmaster named Leavy had argued for the bridge with great effect. It was too late in the day to start objecting to the bridge, he said. He said he never had had any trouble striking top spars on a ship; indeed, to those shipowners who were claiming it would cost five hundred dollars to strip a ship to pass under the bridge, he said it would be a pleasure to do the job for them at that price. Then he finished his speech by asking, if the bridge were not finished now, “What were they to do with the towers?” It was a question that appeared to dismiss the whole issue, which it did not, as things turned out, but for the moment the bridge had passed through one more trial, intact and in good part because the colossal twin towers seemed to provide a certain psychological momentum it had not had before.