St. Nicholas/Volume 40/Number 10/With Men Who Do Things
WITH MEN WHO DO THINGS
BY A. RUSSELL BOND
Author of “The Scientific American Boy” and “Handyman’s Workshop and Laboratory”
Chapter X
1100 FEET UNDER THE HUDSON—“NO WHISTLING ALLOWED!”
We were soon told, in answer ta our questions, that the shafts at each side of the river had been sunk to their full depth, and the “headings” had been pushed so far that there was only about a hundred feet more of rock to cut through.
The trip down that shaft seemed never-ending, and when we looked up from the bottom, the opening at the top showed as a tiny patch of light in the distance, “no bigger than a quarter,” as Will described it.
“I suppose the atmosphere down here is quite noticeably denser than on the surface,” said Will, puckering up his lips to see whether he could whistle.
“Don’t! Don’t do that!” shouted the superintendent, leaping forward and clapping his hand over Will’s mouth.
“Wha’—what ’s the matter?’ gasped Will, in astonishment.
“Simply this: our miners on this work are all southern Negroes, and a more superstitious lot you could n’t find anywhere, They have a strange notion that if any one whistles under ground, bad luck is sure to follow. More than once they ’ve quit work because of some silly superstition. Why, they stampeded out of the tunnel a couple of weeks ago, merely because a lady visitor came down to see the work. That meant bad luck sure, and nothing could induce them to go to work again until the next day,”
After our previous whistling experience, we were inclined to think that this was another joke on us, but we did n’t quite dare to say so. And when we asked some other engineers about it, we were assured that it was a fact.
At the bottom of the shaft, there was an electric “dinky” (locomotive) and a couple of “muck” cars. We climbed into one of the cars, and, at a signal to the “dinky skinner” (locomotive engineer), we were off. The moisture in the tunnel made such a thick fog that we could not see anything but the faint glow of the electric lamps, strung at infrequent intervals along the roof. Once in a while we passed the shadowy form of a workman, drawing back at the warning of our gong to let us pass,
At first, all other sounds seemed to have been drowned out by the noise of our train, which echoed strangely in that long rock cavern, but gradually another sound rose above the din, a sound that grew louder until it became fairly deafening.
And just then our train stopped, and we jumped. out to watch the drill gang at work. The racket was of a throbbing nature most distressing to the ears, and very trying for the nerves. Altogether, there must have been half a dozen drills, all going at once, pounding their steels into the rock like a riveting-hammer, at the rate of about 400 blows per minute, Once I visited a boiler-shop, and thought that the noise there was about as distracting as any noise could be, but that was quiet compared to this racket. Under the rapid blows the rock beneath the steels was reduced to a fine powder, which, in the case of all holes which slanted downward, was washed out by streams of water.
Before we went down the shaft, the superintendent explained just how the holes were arranged (see page 928). The upper half, or “heading” of the tunnel, was run about twenty yards in advance of the lower half, or “bench,” so as to hasten the borings and enable two drill gangs to work at the same time, It is comparatively easy to blast away the “bench,” because the “shot” holes are drilled downward from the flat, upper surface, and when the dynamite is set off, it splits away the rock in slabs; but in the case of the “heading,” a special arrangement of “shot” holes is necessary, because the rock can be attacked only from the face. The first thing to be done is to remove a wedge, or “cut,” from the center of the “heading”; two rows of holes are driven in at an angle so that they will meet, or nearly meet, at a depth of about eight feet back from the face of the rock, Alter this wedge has been blasted out, it is not so difficult to split out the rest of the heading. At each side of the “cut” a row of “relief,” or side, holes is drilled, and finally a set of “liners,” or rim holes, that slant outward to some extent, so that the rock will be shattered to the full diameter of the tunnel. After the holes are drilled, the cut is blasted out first, then the “relief” holes, and, finally, the “liners.”
The bench-drills were mounted on tripods so that they could drill vertically, but the drills at the heading were carried on two posts or columns that were tightly wedged between the bench and the rock roof overhead by means of jack-screws. There were three “engines” on each column, so mounted that they could be turned in any desired direction, We watched one of them starting a hole on a shelving piece of rock. The steel was pounding with short, quick strokes, trying to hammer out a seat for itself, while sparks were dancing around the drill point. After a while, when a sufficient hollow had been pounded in the rock, the steel began to strike with longer and longer blows, until it reached a full seven-inch stroke. The exhausts of the drills were coated with something white and glistening. One of the men scraped off a bit of the stuff and handed it to me. It was frost! I stared in astonishment! We could n't, comfortably, do any talking down there, but when finally we got back to the surface, the superintendent explained it to us as follows:
“These drills are run by air compressed to one hundred pounds per square inch, When that air is compressed, up at the pumping station, it gets so hot that it blisters all the paint off the compressors, where they are not protected by water-jackets; in fact, it gets so hot that we cannot bring it to the full one hundred pounds at once but have to compress it in two stages, and cool it off between stages. You know how it is with a bicycle pump, don’t you? 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. It absorbs so much heat out of its surroundings, that any moisture it contains is condensed, and settles as frost around the exhaust-port. In fact, if we don’t watch carefully, it is likely to freeze the parts fast.”
We went down the shaft again later, to watch the charging of the holes after the drilling wascompleted. The drill boss began first with his “cut” holes. The dynamite cartridges were about eight inches long and an inch and a half in diameter, wrapped in paper tubes. The man would take a stick of the dynamite, or “powder,” as miners call all explosives, place it in the hole, and press it home with a wooden ramrod, so that the paper wrapper would burst open, and the soft, putty-like stuff would be mashed out to fill the hole completely. Other sticks of dynamite were then put in, each being rammed up against the preceding one. In one of the sticks he jabbed a wooden marlinespike, to make a hole for the detonating cap, After sticking the cap in place and fastening it with a half-hitch of the electric wires around the cartridge, he rammed it up against the rest of the dynamite, then put in a few more sticks, and finally closed the hole with a cartridge filled with sand. Extra heavy charges are always necessary to remove the “cut.”
About ten or a dozen sticks were used to each
hole. ‘The wires to the detonating caps protruded
WATERPROOFING CONCRETE TROUGH WHICH IS TO CARRY THE AQUEDUCT WATER ACROSS IRONDEQUOIT CREEK. from the holes, and the foreman connected them to a pair of line-wires that ran back to a bulkhead, or strong oaken shelter, about 300 feet away. When everything was ready, the men would hide behind this bulkhead while the boss did the “shooting” by closing an electric switch.
The superintendent thought it a little too dangerous for us to stay there, so we went all the way back to the shaft. As we were on our way, there was a sudden crash that sounded like a pistol-shot directly overhead. Will and I both jumped a yard. We thought the dynamite had exploded. The superintendent only laughed at us.
“That is nothing but the flaking of a piece of rock overhead,” he explained; “you must remember that we are going through rock that was made ages ago, and is under enormous pressure. When we cut a big hole through rock of this kind, the pressure is relieved to some extent, and the rock actually expands into the bore, This
THE DOWN-STREAM FACE OF THE MASONRY PORTION OF THE OLIVE BRIDGE DAM.
By the time he finished talking, we reached the shaft and were carried up to the surface. Suddenly, a boom and a dull roar told us that the powder had done its job down there deep in the rock. We were anxious to see what the shot had accomplished, but we were not permitted to go in again.
“Don’t you know that the fumes of ‘shooting’ are poisonous?” asked the superintendent,
“But how about the men?” I asked. “Won’t it Kill them, too?
“We pump air in there to blow the fumes out. In about five minutes, they can go back and charge the ‘relief’ holes. But if you went in there, it would give you an awful headache. The men get used to it, but in time even they are liable to be overcome. By the way, you ought to see
A CONCRETE BULKHEAD IN THE TUNNEL 1100 FEET UNDER THE HUDSON RIVER. how they stare dynamite in New York. It is interesting. The Bureau of Combustibles will not let any one keep a large quantity of explosives in the city, particularly in congested parts, but at each shaft they use from seven to eight hundred pounds of powder per day, so they have underground magazines hewn out of solid rock. When you get back to town, call un my friend Douglas, at Shaft 13, and he will show you one of the magazines and how it is constructed,”
Chapter XI
CAGING DYNAMITE
“Did you ever smell dynamite?” said Mr. Donglas, picking up a stick and holding it under my nose, I jumped back in alarm. “Oh, it won’t hurt you!” he said reassuringly; “but if you smell of that sickish stuff awhile, it will give you a headache. Now if this powder should go off—" Mr. Douglas paused.
“Yes?” I said nervously.
“Oh, we do not expect such a thing ever to happen, but you never can quite tell about dynamite, If it is n’t perfectly fresh, it might go off if you sneezed upon it, You know dynamite is made of nitroglycerin and gelatin. When it is exposed to extremes of heat or cold and moisture, the glycerin separates from the gelatin, and col-fects in little bubbles that are extremely sensitive and will go off at the least provocation,
“I remember once,” continued Mr. Douglas, “when I was only a lad, my brother and I were anxious to try our hand at ‘shooting’ Father was a contractor, and was doing a job out in Oregon, and we boys worked there, with the men. Well, as 1 was saying, one day when the men were off at lunch, we went to the dynamite house and got out a case of dynamite.
“HOLED THROUGH,” THE JUNCTION OF TWO TUNNEL HEADINGS. The heading was all ready for the powder, and we thought we could shoot it just as well as any one else. I carried the case of dynamite over to the shaft while my brother was getting the fuses. When I got to the shaft, the bucket was up at the top, near enough, as I thought, for me to reach over and put the case of dynamite on it, even though it did weigh fifty pounds. However, as I leaned over the edge of the shaft, I kicked against a pick or a shovel that lay in my way, and this hit the bucket and pushed it out of my reach; but I had leaned so far that it was impossible for me to regain my equilibrium, and I had the alternative of dropping the fifty pounds of dynamite, or falling down the shaft with it. It did n’t take me a second to make my choice, and then, as the case shot down the shaft, I ran. Yes, I did some real running. My brother saw me coming, took one glance at my face, and then he also ran some. So did the engineer of the hoisting-engine. The shaft was n’t more than one hundred and eighty
feet deep, but we ran long enough for that dynamite to haye dropped ten times as far. Then we stopped ta collect our wits. Well, sir, that powder never went off! When my father heard about it the next day, he made it the text of a sermon. All the men were lined up to hear his speech, and it certainly made an impression upon me. ‘I want you to understand,’ says he, ‘that dynamite is dangerous stuff to handle, even though a case of it did fall one hundred and eighty feet with- out exploding. It is dangerous stuff, I tell you, and should always be treated with respect. After that incident of yesterday, you may get the notion that all this talk about the danger of dynamite is mere nonsense, but, let me tell you, that dynamite was perfectly fresh. Two or three months from now that very same powder will be so touchy that you cannot drop a pebble on it without setting it off. The only way to handle dynamite safely is to treat it with due respect always, because you never can tell in just what condition it is,
“Well, as I was saying, if this powder here should happen to go off,” resumed Mr, Douglas, with exasperating deliberation, “the explosion wave would smash into that pocket at the other end of the chamber, where it would come up against a wall of solid rock; then it would have to go off at right angles down the passage, where it would find itself in another pocket: again it would have to dart at right angles, only to dash into the third pocket, and by the time it found its way out to the door, it would have lost much of its energy, and then it would hit the door with a gentle shove of something like five hundred and forty tons, or about one million pounds. It sounds like a long story, but it would all happen like that,” and he snapped his fingers, “The door would slam shut, and the poisonous fumes would be trapped inside without any way of escape. 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. But the men outside would not be in danger, and the busy city two hundred and fifty feet above would scarcely know that anything had happened.”
“But,” said Will, who had been by no means convinced, “I thought nothing could stand up against such a quantity of dynamite. I don't see how any door can hold it.”
“Do you know,” said Mr, Douglas, “there is more energy in a pound of gasolene than in a
THE DOORWAY LEADING INTO THE DYNAMITE MAGAZINE. pound of dynamite? But here is the difference, gasolene combustion is comparatively slow, while the chief value of dynamite is the suddenness of its explosion. It is chiefly that first explosion wave that we must guard against, and so we make it dash itself against the rock walls until it is pretty well spent. This door here” (we had come to the end of the passageway by this time), “is made to stand twice the pressure that we estimate it will be subjected to. See, it is built of heavy steel I-beams, with oak timbers twelve inches square between them; and then the door-way is set in an enormous mass of concrete, Oh, no, it could not possibly give way.”
“But have you tried it?” asked Will,
“Oh, yes: we exploded half a dozen sticks just around the first bend, and it slammed the door shut, nicely, and the drain here—but I have n't shown you that yet.” here was a gutter running down the center of the rock floor of the passage to carry off any moisture that might seep in. “We have to run that drain through to the outside, and that ventilating pipe you see overhead also has to have some connection with the outside, and so we have an opening under that plate in the floor and a tapered plug hanging on a guide rod just in front of the opening. Well, as I was saying, when the powder went off, it drove that plug in the drain so hard that we had to use a hydraulic jack to force it out,”
“But,” persisted Will, “you have never exploded a full charge of one thousand pounds, have you?”
Mr, Douglas laughed. “Look here, young man, you would make a pretty good lawyer. No, we have never tried it here, but in Europe, where the idea originated, because they have to do so much mining right under large towns, fully as much powder as that was set off once without the slightest damage to anything outside, There was a small car in front of the door of the magazine, but it was not in the least affected by the explosion.”
It was wonderful, and I was glad we had seen it, but all the same it was a decided relief to step out of that deadly chamber.
Just as we emerged from the magazine, the lights in the tunnel began to wink slowly once, twice, three times.
“Hello!” exclaimed Mr. Douglas, “that is the signal to hunt for cover, They are going to shoot the heading in half a minute. We had hetter step into the magazine to be sure that no flying pieces of rock hit us,”
“The magazine!" I cried in astonishment. Of all places on earth that was the last I would ever seek as a refuge from a blast, but I was hustled into the place before I had time to make any protest.
When we got inside, I expected them to shut the door. In fact, Will and I both tried to shut the door because we knew there was no time to lose, as Mr. Douglas had said that the shot would be fired in half a minute after the signal. But he motioned to us to desist. “We never close that door. That counterweight is put there for the very purpose of holding the door open,” he said, pointing to a rope that ran from the top of the door over a pulley on the wall, and was attached to a heavy iron weight.
You can imagine our feelings. Forced to seek shelter in a cave charged with dynamite, a thousand pounds of it! What was to prevent the shock from setting it off? and then where would we be? A thousand thoughts chased through my brain in the brief moment before the explosion came.
It is a curious thing about blasting, that the sound travels through the rock much faster than it does through the air, and so there is always a warning crack an instant before the crash of the air wave reaches the ear. Just before the warning sound came, the superintendent shouted something that I did n’t catch; but I saw him grab at his hat, and I followed his example, not a moment too soon, The next instant, I was engulfed in a terrific roar of noise and a rush of wind that all but swept me over on my back, But as I reeled, another blast came out of the magazine behind me, and pitched me forward. I thought for the moment that the dynamite had been exploded by the concussion, and I made for the door. I was conscious that the door actually
“WILL HAD NOT BEEN QUICK ENOUGH TO GRAB HIS HAT.” swayed forward a bit, and then settled back under the pull of the counterweight. Then I saw the superintendent laughing, but he was laughing at Will, and not at me, thank Heaven Will had not been quick enough to grab his hat. The explosion wave had carried it off his head, and sent it sailing around the zigzag passageway of the magazine, but—and that was what the superintendent was laughing at—the return wave coming out of the magazine brought the cap sailing back, and dropped it at his feet!
“That is the beauty of this magazine,” laughed the superintendent, picking up the dirty, bedrageled cap and handing it to Will. “If you had been out in the tunnel, your cap would have sailed off, Heaven knows where, and it might have taken you all day to find it. But here in the magazine it is sure to come back on the return wave. Even though it may be a bit dirty, you will always get your head-gear back again. But we ’d better get out of this before the smoke gets too thick,” Already the smell of the fumes was quite noticeable, as they were being driven out by the air that was being pumped to the heading,
It is a curious fact that when one is going through great dangers, whether real or imaginary, the mind is not infrequently impressed with minor details which come back very vividly to a person when he has time to think over his experiences, While I was imagining all the horrors of death in the magazine, my eyes took in a very curious phenomenon, It all came back to me as we were going up in the cage to the surface. When the first explosion wave struck us, it had seemed as if I could actually see the air wave rush into the passageway like a foggy clond, and dash into the still air about me. But the strangest part was that, as it seemed to hit the still air, drops of water seemed to form under the electric lamp where I was standing, and fall like a scattering rain to the ground,
When I mentioned it to the superintendent, he did not think I was crazy, but told me that my fleeting impression was a fact.
“Yes,” he said, “on a damp day such as this, you can actually see water squeezed out of the moist air if you happen to be standing in a very good light.”