a prudent speed, with only one opening (the natural one, and that well above the water), is liable to dive down so abruptly that the opening, which must be open, goes below the water. For good work,-work as safe as such work ever can be, a thorough knowledge of all the conditions of equilibrium and of all the conditions of the ship's resistance is required..

Steel is now made so as to guarantee a submarine against the maximum pressure of the water during its ordinary submersion. But the torpedo boat demands a coefficient of extremely high security for the depths that it may be called upon to explore, and without warning. It may be dragged down, or it may be precipitated to depths for which its resisting power was not calculated; depths to which no ship would descend of its own will, and once down, there is no one who comes back to report reasons or to make

estimates.

Any leak permitting the passage of a heavy sea prevents all attempts at self-preservation. Compartmentage (with water-tight partitions) would localize leaks and retard the asphyxiation of the crew of a drowning ship. But that fact does not save a crew if it cannot get at any means of safety when shut up in a water-tight box between two boxes full of water. In such a position, how could a crew get at the working gear? How could the ship be sent to the surface?

When the boat sinks and cannot rise by her own means her chance of salvation is small. Hope is vain if the hull is down to such a depth that the column of water must have crushed it hull is intact, and if the sea permits such action, a tube may possibly be let down and fixed upon an opening of the hull, compressed air of high pressure may be passed through the tube, and the boat may be sent to the surface. If there is a leak it may be stopped and the boat driven up. There may be no other way to save the boat than to raise it entirely suspended by tacklings, but this is not an easy matter. The submarine is heavy, and, if hard to balance when running at full speed, what must it be to tackle it in a heavy sea? As to explosions, a careful crew can pre

had such an event been the alternative. If the

vent them. Unless the ship is sailing with hood. open, when the ventilation is intense, there is no emission of dangerous vapors.

Life in the Submarine.

Nothing but real experience can give an idea of the desperate conditions of the life, the unceasing effort, the crushing labor, of the men who serve in the submarine torpedo boat, the long steel tube which at any instant may become their coffin. From an article in the Annales (Paris), by M. Durand, we glean the following:

The interior of the submarine is a narrow runway, like a space between piled-up packing boxes left open to permit the passage of the handlers. The inner sides are lined with the cases containing the generators, which run through the ship from end to end. In the narrow passage between the generators live the men. Each has his place; it is his by rigorous official assignment. Down there the least of liberties would be fatal. Running along the ceiling of this death-trap are the wires, painted white : or red, the boat's arteries, circulating the power that animates the different organs, while along the inner sides or walls are the dials of the indicators and the shining knobs of the generators. When the ship dives lights are reverberated from the gleaming metal, and for an instant they reveal the anguish of the crew; the ghastly faces, every nerve tense, appear and vanish. Then the boat shifts, and black darkness falls again.

Immediately under the only opening in the steel tube directly in the center of the ship is the place corresponding to the "office" of men who live under normal conditions. Here is a place just large enough to hold a man. It is called the maneuver bureau, or some other equally high-sounding name. The motors, the dynamos which furnish the power of propulsion, are usually in the rear.

Breathless, tight-sealed as in a tomb, is the place where the men do their deadly work:

Cramped there, within limitations just large enough to hold their bodies, hang the crew, eyes haggard, hair drenched with acrid sweat, jaws set, crushing back the tortured impulses of the physical. They cannot stretch leg or arm; they know that they poise the ship; let them stir a

muscle and the whole ship trembles. There is no exercise, no rest. To relax self-control, to forget, is fatal, and an unguarded movement may bring about death under appalling circumstances. The watch is on day and night. But down there there is no day. It is always night, -not the night of rest, but the night of torment. The boat is balanced, the men cramped into, their allotted places, and the man who maneuvers the ship is on the top rung of a little iron ladder running straight up and down under the cap of the ship.

are

On one of the rungs of the ladder crouches the first officer, with feet wide apart, balancing the ship. The second officer is on a rung below, his head between the knees of the first. The second officer gives the orders. There they perch on the torturing rungs of their ladder, and there they are forced to hang during the greater part of the maneuvers. The ship is ready for her work. 'On guard to the plunger! fill the ballast!" From the instant that the ballasts are

full,-silence, black night, anguish! The life of the depths has begun, and all communication with the world has ceased. They are darting down. The engines are driving. It has begun! The submarine is rushing downward like a frightened fish,—not borne downward by her weight, but forced downward by her propelling power and steered downward by her helm. There is no rest for her. To rest for a submarine is to rush upward. Rest, ever so little, and she would appear above the surface. She must keep moving to keep down. That is the way she works, forever moving until her work is done. As for the men who run her, sealed in her hollow tube,-in war they are on deadly duty; in peace on drill almost as deadly. As men they have ceased to be. Once on duty as torpedoists they are nothing but elements of the submarine, an integral part of it. Down there is the noisome darkness of that pulsing thing; they are one with the wires of the dynamos. They are part of the machinery. The only difference between them and the other parts of the working gear is that they can suffer.

THE

HE modern method of constructing a tunnel under a river differs very materially from that used by the ancients. When the Assyrians wanted to build a tunnel under the Euphrates a new channel was dug, a dam erected, and a continuous arch of water-tight masonry was then built along the bottom of the old channel, after which the dam was removed and the water allowed to flow in its old bed. But, with no interruption to commerce, and with a speed equal to that of railroad construction in a mountainous country, over a dozen tunnels are now burrowing their way under the waters surrounding New York city. The methods of construction and the difficulties that have to be overcome are described by Charles H. Cochrane in Moody's Magazine (New York) for December.

The approximate cost of these 14 tunnels is $200,000,000, or about one-fifth of a billion dollars; and they are built for one purpose only, to save time. It is estimated that at least a million people go in and out of Manhattan every day. At the average of 25 cents an hour in value, this will mean a saving of $62,500 a day, or $23,000,000 a year. The construction of these tunnels constitutes one of the most notable engineering achievements of the age, not less costly and difficult in execution than the Panama Canal, though not the occasion of domestic or international agitation.

by the Pennsylvania Railroad: four under the East River, and two under the Hudson, thus giving uninterrupted subway connection between New Jersey and Long Island. Indeed, if rumor be true, when the Pennsylvania tunnels are completed, transatlantic passengers will soon be taking the steamer at Montauk Point, thus cutting down the trip from New York to Europe seven hours.

The two Manhattan tubes near Christopher street will serve as a subway to railway depots in both Jersey City and Hoboken. The tubes from Jersey City to Cortlandt street, within a block of Broadway, will relieve the congestion of lower Manhattan, and the Battery tubes connecting with the new Brooklyn subway will help materially in lessening the traffic on Brooklyn Bridge. Further north, connecting Grand Central Station with Brooklyn, are the two Belmont tubes, which have been promised for completion early in 1907, though a recent daily press report states that two years will be necessary to complete the work.

Thus, enter New York from what direction you will," a tunnel is waiting to receive you, and the time that used to be lost in changing cars and crossing ferries will soon be reduced to five minutes of tunnel travel, ending in arrival in the glare of Broadway or some other center of activity in the greatest city of the western world."

The method adopted in the construction of

After the soil through which the tunnel was to pass had been determined by means of the diamond drill,

perpendicular well-like shafts were sunk in the earth near the river margin... When a shaft was down about 50 or 60 feet, the rock was blasted out on both sides to form headings, one leading toward the tunnel entrance inland. and the other leading down under the river. .. A great steel cylinder called a shield is set up in the heading and pushed forward under the river.

This shield is about 2 feet larger in diameter than the tunnel tube, and allows the forward

The.

end of the tunnel to be built inside of it. shield is pushed forward at regular intervals by a series of powerful jack-screws, and thus the work advances. When the tunnel goes through soft sand and mud, the front end of the shield is closed, and it is forced ahead, making an aperture for the tubing; but when the tunnel course lies through rock or hard earth, the front is partly opened by gates, and workmen blast the rock or dig out the earth and pass it back through the air locks.

The atmospheric pressure due to the airlocks is often over 50 pounds to the square inch. Only the stoutest hearts and physiques can work under such a strain, and of course wages are high for such labor. A physician. is always near, and when a workman shows any signs of having contracted the "bends," as the caisson disease is called, he is at once sent to the hospital for treatment.

Special difficulty has been experienced with the Pennsylvania tubes under the East River because of blowouts, the excess of air pressure at the tunnel headings forcing its way to the surface through the thin layer of shifting slime. To check this, the soil over the tunnels has been thickened and strengthened by dumping bags of clay into the river from scows. To make the foundation more secure, screw piles were run through the tunnel bottom at intervals of a few yards, the screws taking a grip on the hard earth far below, thus forming a row of anchors that nothing short of an earthquake could loosen." The tunnel tubes themselves are made in sections, and are built of cast iron reinforced with cement. The interior is lined with

cement, and benches of concrete on the sides make footpaths for workmen. The ties are bedded in the concrete.

EFFECT ON NEW YORK'S SUBURBS.

The motive power for the cars will be electricity, and the third-rail system will be used. There will be no smoke, no cinders, and no darkness, for each tube will be perpetually lighted by electric lamps strung at intervals along the course. All the tunnels are in pairs, and trains run only in one direction; so that only rear-end collisions will have to be guarded against. Thus will the zone of transportation by electric power be enlarged, for the Erie, the New York Central, and other roads contemplate using that power for all suburban passenger service.

Mr. Cochrane estimates the probable gains in realty values in the vicinity of New York, resulting directly from the tunnel improvements, at more than the total cost of the tunnels, great as that sum is. Thus it appears that the saving of a half-hour in thousands of commuters' time is not to be the sole material benefit of these great works.