Part 50

When the shell has been completely cleaned out by means of the blast of compressed air, the exposed rock can be examined by lowering an electric light. Steel sounding rods are employed to test the hardness of the rock and to detect the difference between soft and hard bed rock. After the piles in each pier have been cleaned out, they must be cut off at absolutely the same height--sometimes a very difficult task when there is little room. The oxy-acetylene torch is used for the purpose, the intensely hot flame cutting off the steel almost like butter at the exact elevation desired.

~PILES ARE NEXT FILLED WITH CONCRETE~

The hollow shell is next filled with concrete reinforced by means of long two-inch steel rods, sometimes fifty feet in length. On clusters of these concrete-filled piles, the weight of the building is supported.

That this method of constructing foundations is indeed rapid, the story of the work at 145-147 West Twenty-eighth Street, New York City, proves. Rock was located 38 feet below the curb. The material above it was clay and water-bearing sand. Structural steel was due in three weeks, but the completion of the cellar was still ten days off. The steel pile foundation method offered the only solution of the problem. Specifications were drawn which called for eighty-five 12-inch steel piles, driven to rock, blown clean by compressed air, and filled with concrete, reinforced with 2-inch rods. Despite various obstructions on the ground (shoring of neighboring buildings and the like) the driving was started on June 30th. The excavator was still taking out his runway while the rear half of the lot was completely driven. After he had left the ground a compressor was set up, and the first pipe was blown on July 7th. Three days later all driving and cleaning had been completed. During the following two days all the piles were filled and capped. In a word, the entire foundation had been completed three days before the expected arrival of the steel.

Such rapid work is not unusual with the steel foundation method. On another contract, work was completed not in the three months stipulated, but in exactly one month and a half, during which brief time all the excavation had been done, including sheeting, shoring, pile-driving, the mounting of concrete girders to carry the wall and capping of the piles ready to receive the grillage.

Sometimes difficulties are encountered which would prove all but insurmountable and certainly hopelessly expensive with other methods. Thus in carrying out the one contract, water was found 12 feet from the curb. Two running streams had intersected at that point. The piles were simply sunk through the stream to rock bottom without any difficulty.

The excessive cost of open-pit work has sometimes made it impossible to build twelve or fourteen-story buildings in many sections of the city of New York. The steel pile has, however, made steel building construction profitable.

The carrying capacity of a steel pile is enormous. On a single 12-inch steel pile one hundred tons can be safely maintained. Piers containing sixteen piles have been used, and loadings up to 1300 tons are not unusual.

Naturally the question arises: Do the steel piles deteriorate in time? The question has been answered over and over again by the piles themselves. After a service of fifteen years the steel foundation piles were removed from the site of a building which now stands at the northwest corner of Wall and Nassau streets, in New York City. They showed practically no deterioration. The oxidation on the outside was almost negligible.

The Story in a Glass of Water

How Does the Water Get into the Faucet?

It is easy for you boys and girls who live in the city to run into the kitchen or bathroom when you are thirsty and by a simple turn of the faucet tap secure a glass of cool and refreshing water, but did you ever stop to think how many men must constantly work and how great and perfect arrangements must be made before it is possible to supply a great city with water to drink, to bathe in, and for cooking and washing?

No one who has never had the experience of being in a town or city from which the water supply has been cut off, for a day or a number of days, can realize how necessary water is in our daily lives. We are so used to having all the water we want at any time that we even complain when in summer we are asked to drink water which is not iced. Drinking ice-water is very much of a habit. In tropical countries where there is no ice, people drink the water just as they find it, and if you were to go there and drink the waters for a few days, you would soon find that the water slakes your thirst even when quite warm, so it is not the ice in the water that quenches your thirst, but the water itself, and the ice-water is not good for you, as the doctor will tell you, because it chills the stomach.

Where Does Our Drinking Water Come from?

The best way to find out where the water in the faucet comes from is to follow it back to its source. Let us see. Here we are in the kitchen and you have just had a drink of water taken from the faucet above the sink. The faucet, you will notice, is attached to a small pipe which is fastened to the wall back of the sink. We look under the sink and see that the pipe goes through a hole in the floor, so we reason that the water must come from the cellar. Let us go down cellar and see. Yes, here is the little pipe that comes down through the floor under the sink and we follow it along the wall toward the front of the house, and well, well, there it goes right out through the stone foundation of the house. So we conclude that the water comes from somewhere outside of the house, and that the little pipe we have been following is only a means of getting it from the outside into the house. We now mark the place in the wall where the pipe goes through and run around to the front of the house to see where it comes out, but we don’t see it. It must be buried in the ground, so we get a spade and pick and begin to dig a hole in the ground, and pretty soon we find the little pipe pointing straight out toward the street. We keep on digging the dirt away, and thus open a little trench from the house to the middle of the street and when we get there after a great deal of digging we find our little pipe attached to a larger pipe which seems to run along the ground in the middle of the street; so we are still in the dark as to where the water comes from, excepting that so far as our own home is concerned we know that it gets into the house through a little pipe which is attached to a big pipe in the middle of the street. By this time we know we have a big job on hand.

~HOW THE PIPES RUN THROUGH THE STREET~

We are pretty tired of digging by this time, so we call in all the boys and girls in town to help us dig so that we may see where these pipes come from, and we have a regular digging carnival. We follow the big pipe along our own street until we come to the corner. Here we find that our larger street pipe is connected with a still larger pipe, so we think we had better follow the larger pipe. We keep on digging, getting more of the boys and girls to help, and we follow that big pipe right out to the edge of town where we see it runs into another stone wall which you knew all the time was the reservoir, but concerning what it was for you were perhaps never quite clear.

Right near the place where the pipe goes in is a stairway which leads up to the top of the wall, so the whole crowd of boys and girls climb the steps and you are at the top of the reservoir; and there spread out before you, you see a big lake surrounded with a stone wall and you see where the water comes from--the reservoir--at least so you think. But you are wrong. You really haven’t come anywhere near the source of the supply. For soon as you walk around the broad top of the wall which surrounds your reservoir, you meet a man who asks you what you want, and you tell him that you have been finding out where the water in the faucet came from, but having found out you thought you would go back home.

The man smiles at you, but, as he is good-natured and sees you are really trying to find out where the water comes from, he tells you that since you have gone to all the trouble of digging up the streets to follow the pipes, you might as well learn all about it.

He first tells you that the reservoir is not really the place where the water comes from but only a tank, so to speak. He explains to you that most of the faucets in the city are higher than the real source of the water, which is out in the country miles away, and as water will not run up hill, it is necessary to keep the city’s daily supply in some place that is higher than the highest faucet in the city, so that it will force its way into and fill to the very end all of the large pipes in the streets and the small pipes which go into the houses, so that the water will come out just as soon as you turn the faucet.

Then he takes you over to a large building near the reservoir which you have always called the water works, but never knew exactly what it was for. He takes you into a large room where there is a lot of nice-looking machinery working away steadily but quietly, and tells you that these are the great pumps which lift the water from the great pipes which bring it from far away in the country, into the reservoir we have just seen, from which the water runs into and fills all of the pipes into the city.

He also tells you that in some cities it is impossible to find a place to build a reservoir which is higher than the highest places in the city. In such places, the pumps in the water works pump the water direct into the city water pipes and force the water to the very end of all the pipes and keep it there under pressure all the time.

From the pumping station he takes you down stairs in the water works and shows you the huge pipe which brings the water to the water works from the country. It is quite the largest pipe you ever saw. You see it is not really an iron pipe, but built of concrete, which is quite as good. You will be surprised to have our friend, the water-works man, tell you that three average-sized men could stand up on each other’s shoulders inside the great pipe.

Our water-works man sees how earnest you are in seeing just where the water comes from, so he proposes that we go find out. We go outside and there is an automobile all ready to go and we jump in and the machine starts off along quite one of the nicest roads you were ever on. Soon you exclaim, “Why, this is the aqueduct road,” and so it is. The great pipe through which the water comes to the city is an aqueduct and they have built the road right over the place where the aqueduct runs. Away we go as fast as the car can carry us, sometimes ten, or twenty or perhaps fifty miles, according to what city you are in. The city goes as far as it must to find a supply of pure water and plenty of it and spends millions upon millions of dollars to make its supply of water good and certain. Occasionally we come to a little stone house along the way where we can go down and see the sides of the great stone pipe. After a while, however, we find our aqueduct road comes to an abrupt stop before another great stone wall. It is the great dam which has been built out there in the country to form one end of a great tank that catches and holds the waters from the creeks and rivers that flow into it. Usually the dam is built up right across a river. They simply build the dam strong enough to stop the river from going any further. Then, of course, the water piles up on the other side of the dam and occasionally this tank, which is simply another huge reservoir, gets so full that the water flows over. It does not really overflow the top of the dam, because underneath the top the engineers have left openings here and there for the water to get through. If it were not for these loopholes, so to speak, the great wall of water within the reservoir, piled against the dam, would break down the wall no matter how well built, by the great pressure it exerts.

~THE REAL SOURCE OF THE WATER~

We are now near to the real source of the water. We take a trip around the top of the great reservoir. Around at the other end we find what looks like a river, excepting that there isn’t any current to speak of. It is a river, but a much deeper one than it would have been but for the dam which has been built across it, and originally its surface was quite far down in a valley. Sometimes man makes his water dam at one end of a lake, which has been formed by streams flowing into a valley which has no opening for the water to run out of. In these cases the lake will be high up in the hills and man simply builds his dam at one end, lets the end of his aqueduct into the bottom of the lake and the water flows. In other cases he picks out a valley where there is no lake at all, builds his dam and then drains the water which he finds in small lakes higher up in the hills into the one big valley and makes a very large lake. But the water in the lakes comes originally from the creeks, rivers or springs which run into it, and so we will follow our original river back into the hills. Here and there along its course we find a little stream flowing into our river and, as we go up higher and higher into the hills, we find our river getting smaller and smaller. Now it is only a creek and, if we go far enough, we find its source but the tiniest kind of a tinkling brook with the water dripping almost noiselessly between the rocks as it makes its path down the side of the hill. There is the source of the water in the glass you have just enjoyed.

What is Carbonic Acid?

It was formerly called fixed air, and is a gaseous compound of carbon and oxygen. It is procured by the processes of combustion and respiration, and hence is always present in the air, though in minute quantity. Plants live upon it and absorb it into their tissues; they abstract and assimilate its carbon, and return its oxygen to the atmosphere in a pure condition. It is also present in spring water, and often in quantities, so that it sparkles and effervesces; it is also produced during the processes of putrefaction, fermentation, and slow decay of animal and vegetable substances in presence of air. It is largely employed by the manufacturers of aerated bread and aerated waters. Under a pressure of about 600 pounds it liquefies, and when allowed to escape through a small jet it rapidly evaporates and causes intense cold, so much so as to become frozen. It does not support burning. The gas derived from it, carbon dioxide, is invisible, and is heavier than air by one half, and has a pungent odor and slightly acid taste. In a pure state the gas cannot be respired, as it supports neither respiration nor combustion. When the portion in the atmosphere is increased to a considerable extent, as happens sometimes, it endangers life. The familiar “rising” of bread is brought about by carbonic acid gas escaping through and permeating the dough, making it light and porous. In this form it is known as yeast or as baking powder. We see its uses also in the chemical fire-engine.

In some parts of the world large quantities of carbonic acid gas are constantly issuing from openings of the earth’s surface. Two such places are the famous Poison Valley of Java, and the Grotto del Cane, near Naples, in Italy. The former is a small valley about a half a mile around and about thirty-five feet deep, in which the air is so loaded with carbonic acid gas that animals entering it are killed in a few minutes. Even birds that fly over the valley are overcome if they do not rise high above it. The Grotto del Cane, or Grotto of the Dog, is a small cavern in the crater of a volcano. A stream of carbonic acid gas flows constantly into the grotto, but the level of the gas does not reach the height of a man’s mouth. When the same air is breathed over and over again, the quantity of carbonic acid in it is increased so much, that it may become as deadly as the air in the Poison Valley.

Two other gases that may generally be found in air are ozone and ammonia. The first is merely a form of oxygen that is produced by the passage of lightning through the air. After severe thunderstorms, it is said to be present, sometimes, in sufficient proportion to give to the air a slightly pungent odor. It is more active chemically than is the ordinary form of oxygen, and consequently has a stimulating effect upon animals.