Alexander Russell Bond

“ Ludlow, boys, is the chief engineer of the new East River suspension-bridge.” Then he proceeded to sing our praises to the bridge engineer, much to our embarrassment. “Why, they have been actually groveling in the mud as sand-hogs for a whole week, just to learn something about tunnel work at first hand instead of through books. Such striving after knowledge, such devotion to engineering, should be encouraged. ”

“ No walls were up as yet, but the outside girders were so deep all around the floor, that they formed a sort of low parapet which kept a fellow from feeling that he was going to fall off when he went to the edge of the building.
Projecting from the girder about ten feet apart were brackets from which was suspended a scaffold seven stories below, where men were at work on the walls. Below that was Broadway, filled with animated little specks, each tiny man no doubt fully conscious of his own importance. ”

“ We walked in at what appeared to be the main entrance on Broadway. No one stopped us, and we wandered about rather aimlessly. Here and there were busy groups of men. Though we were on the street level, we could look down, at one place, about four stories. There was an engine-room below us, and a place where they were mixing mortar, putting it in wheelbarrows, and then shooting it up, wheelbarrow and all, to the upper floors, in elevators that moved at terrific speed. “I wonder where the passenger elevator is,” said Will.
“I guess that is it,’ I replied, pointing to a ladder. ”

“ What surprises most people is that the plunger does not have a piston-head on its lower end, but is merely a straight piece of steel tubing down to the very bottom, where it is closed with a cap, and has two or three guides on it to keep it centered in the cylinder. When the water is forced in, it exerts a pressure in all directions on the cylinder as well as on the plunger, but nothing can yield to that pressure except the bottom of the plunger, which is raised, and so pushes the elevator car up. ”

“ The bottom door is closed when the top door is open to let the men in. After they enter the lock, the lock-tender lifts the upper door shut, and turns a valve to let the compressed air in. All the time, the bottom door is kept closed by the air-pressure in the shaft below, but, as air is let into the lock, its pressure at length equals that in the caisson, and, there being nothing to hold up the bottom door, it swings open of its own weight, so that the men can go on down to the working chamber. ”

“ To-day, at any time, you can see a procession of trucks plodding over the bridge, with a string of hurrying trolleys and rushing elevated trains loaded to the limit of capacity with human freight, all supported by the combined strength of those thread-like wires that were spun by human spiders across the East River. ”

“ Uncle Edward was going to put Will in New York, let him spend the summer as he pleased, asking only that he keep a diary of what he saw and did. Then, by looking over the diary, Uncle Edward could tell what Will took to the city with him. In other words, if the diary was full of the engineering sights and wonders of the city, it would show conclusively that Will had brought with him a love for engineering. If no engineering tendencies appeared, Uncle Edward declared that he would not treat Will to a course in college. ”

“ Now, if the brakes should give way on the winding-drum at the top of the shaft while a car is standing empty half-way up the shaft, it would actually fall up instead of down, because it would be so greatly overweighted by the counterbalance. You see, all the motor has to do is to move the difference in weight between the car with its passengers and the counterweight; and this can never equal more than half the weight of the passengers. But I don’t suppose you would find our elevator system half so interesting as the one I am going to send you to. ”

“ Tunneling a city street is no simple task under any conditions. There were sewer-pipes, gas-pipes, water-pipes, electric light and power conduits, telephone, telegraph, and fire-alarm conduits, and the conduits for the underground trolley system of the electric cars, to be avoided. The gas-mains were elevated above the streets so that there would be no danger of an explosion, should they develop a leak, Of course, the man-holes or underground chambers, where connections were made with the telephone-lines, had to be torn away, exposing the lead-sheathed telephone cables. ”

“ What do you do when the caisson is sunk all the way down to rock?”
“We blast out a good footing if the rock is tilted.”
“What! You blast rock down in that small chamber!”
“Oh, yes, the sand-hogs all get out of the chamber when the charge is set off. We have a trap-door at the bottom of the shaft. The men all climb into the shaft and pull up the trap-door, then the gang boss sets off the charges with electricity.”
“But after you have finished blasting, what then?”
“Oh, then we just fill in with concrete. The concrete is laid round the cutting edges first. ”

“ We have it so fixed that there are the proper outlets at each floor, so that all the men have to do at the building is to make the connections at each office, as required. In a building like that, we have two hundred and thirty miles of telephone wiring, enough to reach from New York to Washington, and, as you can imagine, it takes some careful estimating to get the wires in just the right place.” On the third floor of the building, we saw how the cables open out into myriads of wires and are connected to a perfect maze of safety devices on the distributing frames. ”

“ PUSHING THE SHIELD THROUGH SILT AND ROCK.
The rock drillers are protected by an overhanging “apron.” It did n't take us long to put on working clothes and boots. There wassomething weird about the whole affair—the brilliant flaming are lamps here and there casting jet black shadows around the yard; the clank and rattle of machinery; the sound of escaping air; the buckets that came up out of the tunnel, and the swish of the stuff as it slid out into the big hoppers from which it was emptied into carts that hauled it off to fill some low spot in or near the great city. ”

“ There was a miniature navigator’s bridge for use when sailing on the surface, and in front of this were two tubes that reached to a height of over twenty feet from the deck.
“Those are the eyes of the submarine,” said our pilot. “A submarine does not wear its eyes in sockets, as we do, but on the ends of a pair of stalks, like snails or crabs,”
Of course that excited our curiosity, and we fired a broadside of questions at him. ”

“ You can get some idea of the energy of dynamite when I tell you that the gases will exert a steady pressure of one hundred and fifty pounds per inch on every square inch of the chamber in the passage until they cool down. In other words, the powder which in the solid state occupied less than fifteen cubic feet, will be turned into a compressed gas occupying twenty thousand cubic feet. When the gases cool down sufficiently, we can force them out with compressed air. So you see we can let the powder explode without injuring anybody except the magazine tender. ”

“ It gets so hot that you can scarcely bear your hand on the cylinder, just from the heat that is developed in compressing the air, Well, this compressed air we use has to be cooled, before we bring it down into the tunnel, by passing it through radiators and water, or air-cooled cylinders; but if air gives off heat when it is compressed, very naturally it has to absorb heat again when it is expanding, so as to regain what it lost before. ”

“ You ’ve got your logic backward, young man; guns and knives are not an infallible sign of gold, but find your gold first, and then the firearms are sure to appear. We have found lots of firearms and daggers of every conceivable form of ugliness, but as for treasure, it's mighty scarce, though I must admit that we have found some gold, too, It is too bad to spoil your romance, but there is no blood-curdling tale of piracy connected with those weapons, although, no doubt, they were once wielded by desperados. ”

“ We have to build great masses of stonework, and imbed in the masonry enormous steel bars linked together like giant chains, to which the cables are fastened. The anchorages of this bridge are each as long as a city block (225 feet) , and 175 feet wide, and when they are finished, they will be built up as high as an eight-story building.”
With this impressive introduction, Mr. Blanchard led the way up to the anchorage, and let us see for ourselves the huge chain of eye-bars. They were stringing the cables in separate strands, and each strand was fastened to a separate pair of eye-bars. ”

“ The air will burst through the fluid sand and boil up. Sometimes a burst of air will make the water shoot up like a geyser from the surface of the river.”
“What happens when you strike a rock?” Will inquired.
“We have to blast it out of the way, The worst trouble comes when we strike a ledge at the floor of the tunnel, and have soft silt or quicksand overhead. We had a job like that in the North River once. A shelf, or ‘apron,’ was built out from the shield, half-way up, virtually dividing the front of the shield into an upper and lower chamber. ”

“ The building regulations of this city do not allow a weight of more than fifteen tons per square foot on the foundations. A foolish regulation, in my estimation, based on the idea that concrete would crush under a heavier load than that; but the kind of concrete we have nowadays, thoroughly reinforced with steel, will stand a far greater pressure. ”

“ The bottom of each shaft is sealed in with air-tight steel doors, so as to make a rectangular pocket in which the car fits like a plunger in a cylinder. Now, if the car should drop into that pocket at high speed, it would compress the air under it Lo such an extent as to form a pneumatic cushion that would check its fall. Our highest elevator-shaft will be six hundred and eighty feet high, the highest continuous elevator-shaft in the world, and, as you can imagine, a car would be traveling if it fell that far! ”

“ The pressure in the cylinder cannot get away. The work the piston does in squeezing that air is not lost, but is all given back to it on the next stroke, and, in addition, there is the pressure of the exploding charge. There is some loss in the compressed air that sprays the oil into the cylinder, because the heat is extracted from it, and it chills the air in the cylinder; but the loss does n’t amount to very much.”
“What ’s the advantage of an oil engine? I should think coal would be cheaper.”
“Do you know how much power is wasted in steam-engines? ”

“ That is more than all the railroads of the country carry in a week; and railroad injuries run up into the thousands every year. In the Manhattan Syndicate Building, we are going to have the finest system of elevators in the world, all driven by electricity, a regular railroad system, with “locals” and “expresses”—some of them running up to the twenty-eighth floor without a stop.”
“It must take an awful lot of power to lift an elevator,” I remarked.
“Not as much as you think. In fact, it often takes more power to ran an empty car down than a partly loaded one up.” ”

“ They are merely making provision for the future. I suppose, in fifty years’ time, New York will be so large that even this supply of water will not be enough, and then people will have to tap Lake Champlain, or Niagara, or something, You young fellows ought to go up to Ashokan, and see the work they are doing there, They are building a dam a mile long and two hundred and twenty feet high, and then there will be dikes, and embankments, and weirs, making, altogether, about five and one half miles of masonry and earthworks that will turn a whole valley into a lake. ”

“ You can see for yourselves how ridiculously light the load is when you figure it down to square inches. Why, many a fat woman who picks her way across a muddy street on her French heels, exceeds the limit of the building code for pressure on the earth. ”

“ The ‘siphon’ under the river is being put through solid rock, where they do not have to bother with pneumatic pressure. Why, it is just because they wanted solid rock that they had to go so deep. This tunnel is being built to last forever, Nothing short of an earthquake can hurt it, and the chances of an earthquake in New York are pretty slim, according to what geologists tell us. ”

“ In Chicago, most of the buildings are supported on floating foundations, because the sand is so deep that it is impossible to get down to rock. A man can’t work at much more than 110 feet below water-level, because the pressure would be over 47 pounds per square inch. ”