The transformer raises the voltage and sends the electrical current under high pressure over a small wire and so great is this pressure that thousands of horse-power can be sent to great distances over small wires with very little loss.

Water power is now changed to electrical power and transmitted over slender copper wires to the great manufacturing centres of our country to turn the wheels of industry and give employment to thousands.

Nearly one hundred cities in the United States alone are today using electricity supplied by transmitted water-power. Ten years ago Niagara Falls were regarded only as a great natural curiosity of interest only to the sightseer, today those Falls distribute over 100,000 horse-power to Buffalo, Syracuse, Rochester, Toronto and several smaller cities and towns. Wild Niagara has at last indeed been harnessed to the servitude of man. Spier Falls north of Saratoga, practically unheard of before, is now supplying electricity to the industrial communities of Schenectady, Troy, Amsterdam, Albany and half a dozen or so smaller towns.

Rivers and dams, lakes and falls in all parts of the country are being utilized to supply energy, though at the present time only about one-fortieth of the horse-power available through this agent is being made productive. The water conditions of the United States are so favorable that 200,000,000 horse-power could be easily developed, but as it is we have barely enough harnessed to supply 5 million horse-power.

Eighty per cent. of the power used at the present time is produced from fuel. This percentage is sure to decrease in the future for fuel will become scarcer and the high cost will drive fuel power altogether out of the market.

New York State has the largest water power development in the Union, the total being 885,862 horsepower; this fact is chiefly owing to the energy developed by Niagara.

The second State in water-power development is California, the total development being 466,774 horsepower over 1,070 wheels or a unit installation of about 436 H.P.

The third State is Maine with 343,096 horse-power, over 2,707 wheels or an average of about 123 horse-power per wheel.

Lack of s.p.a.ce makes it impossible to enter upon a detailed description of the structural and mechanical features of the various plants and how they were operated for the purpose of turning water into an electric current. The best that can be done is to outline the most noteworthy features which typify the various situations under which power plants are developed and operated.

The water power available under any condition depends princ.i.p.ally upon two factors: First, the amount of fall or hydrostatic head on the wheels; second, the amount of water that can be turned over the wheels.

The conditions vary according to place, there are all kinds of fall and flow. To develop a high power it is necessary to discharge a large volume of water upon properly designed wheels. In many of the western plants where only a small amount of water is available there is a great fall to make up for the larger volume in force coming down upon the wheels. So far as actual energy is concerned it makes no difference whether we develop a certain amount of power by allowing twenty cubic feet of water per second to fall a distance of one foot or allow one cubic foot of water per second to fall a distance of twenty feet.

In one place we may have a plant developing say 10,000 horse-power with a fall of anywhere from twenty to forty feet and in another place a plant of the same capacity with a fall of 1,000, 1,500 or 2,000 feet.

In the former case the short fall is compensated by a great volume of water to produce such a horse-power, while in the latter converse conditions prevail. In many cases the power house is located some distance from the source of supply and from the point where the water is diverted from its course by artificial means.

The Shawinigan Falls of St. Maurice river in Canada occur at two points a short distance apart, the fall at one point being about 50 and at the other 100 feet high. A ca.n.a.l 1,000 feet long takes water from the river above the upper of these falls and delivers it near to the electric power house on the river bank below the lower falls. In this way a hydrostatic head of 125 feet is obtained at the power house. The ca.n.a.l in this case ends on high ground 130 feet from the power house and the water pa.s.ses down to the wheels through steel penstocks 9 feet in diameter.

In a great many cases in level country the water power can only be developed by means of such ca.n.a.ls or pipe lines and the generating stations must be situated away from the points where the water is diverted from its course.

In mountainous country where rivers are comparatively small and their courses are marked by numerous falls and rapids, it is generally necessary to utilize the fall of a stream through some miles of its length in order to get a satisfactory development of power. To reach this result rather long ca.n.a.ls, flumes, or pipe lines must be laid to convey the water to the power stations and deliver it at high pressure.

California offers numerous examples of electric power development with the water that has been carried several miles through artificial channels. An ill.u.s.tration of this cla.s.s of work exists at the electric power house on the bank of the Mokelumne river in the Sierra Nevada mountains. Water is supplied to the wheels in this station under a head of 1,450 feet through pipes 3,600 feet long leading to the top of a near-by hill. To reach this hill the water after its diversion from the Mokelumne river at the dam, flows twenty miles through a ca.n.a.l or ditch and then through 3,000 feet of wooden stave pipe. Although California ranks second in water-power development it is easily the first in the number of its stations, and also be it said, California was the first to realize the possibilities of long distance electrical energy. The line from the 15,000 horsepower plant at Colgate in this State to San Francis...o...b.. way of Mission San Jose, where it is supplied with additional power, has a length of 232 miles and is the longest transmission of electrical energy in the world. The power house at Colgate has a capacity of 11,250 kilowatts in generators, but it is uncertain what part of the output is transmitted to San Francisco, as there are more than 100 substations on the 1,375 miles of circuit in this system.

Another system, even greater than the foregoing which has just been completed is that of the Stanislaus plant in Tuolumme County, California, from which a transmission line on steel towers has been run in Tuolumme, Calaveras, San Joaquin, Alameda and Contra Costa Counties for the delivery of power to mines and to the towns lying about San Francis...o...b..y. The rushing riotous waters of the Stanislaus wasted for so many centuries have been saved by the steel paddles of gigantic turbine water wheels and converted into electricity which carries with the swiftness of thought thousands of horse power energy to the far away cities and towns to be transformed into light and heat and power to run street cars and trains and set in motion the mechanism of mills and factories and make the looms of industry hum with the bustle and activity of life.

It is said that the greatest long distance transmission yet attempted will shortly be undertaken in South Africa where it is proposed to draw power from the famous Victoria Falls. The line from the Falls will run to Johannesburg and through the Rand, a length of 700 miles.

It is claimed the Falls are capable of developing 300,000 electric horse power at all times.

Should this undertaking be accomplished it will be a crowning achievement in electrical science.

CHAPTER XII

WONDERFUL WARSHIPS

Dimensions, Displacements, Cost and Description of Battleships-- Capacity and Speed--Preparing for the Future.

All modern battleships are of steel construction. The basis of all protection on these vessels is the protective deck, which is also common to the armored cruiser and many varieties of gunboats. This deck is of heavy steel covering the whole of the vessel a little above the water-line in the centre; it slopes down from the centre until it meets the sides of the vessel about three feet below the water; it extends the entire length of the ship and is firmly secured at the ends to the heavy stem and stern posts. Underneath this deck are the essentials of the vessel, the boilers and machinery, the magazines and sh.e.l.l rooms, the ammunition cells and all the explosive paraphernalia which must be vigilantly safe-guarded against the attacks of the enemy. Every precaution is taken to insure safety. All openings in the protective deck above are covered with heavy steel gratings to prevent fragments of sh.e.l.l or other combustible substances from getting through to the magazine or powder cells.

The heaviest armor is usually placed at the water line because it is this part of the ship which is the most vulnerable and open to attack and where a sh.e.l.l or projectile would do the most harm. If a hole were torn in the side at this place the vessel would quickly take in water and sink. On this account the armor is made thick and is known as the water-line belt. At the point where the protective deck and the ship's side meet, there is a projection or ledge on which this armor belt rests. Thus it goes down about three feet below the water and it extends to the same distance above.

The barbettes, that is, the parapets supporting the gun turrets, are one forward and one aft. They rest upon the protective deck at the bottom and extend up about four feet above the upper deck. At the top of the barbettes, revolving on rollers, are the turrets, sometimes called the hoods, containing the guns and the leading mechanism and all of the machinery in connection with the same. The turret ammunition hoists lead up from the magazine below, delivering the charges and projectiles for the guns at the very breach so that they can be loaded immediately.

An athwartship line of armor runs from the water line to the barbettes, resting upon the protective deck. In fact, the s.p.a.ce between the protective and upper deck is so closed in with armor, with a barbette at each end, that it is like a citadel or fort or some redoubt well-guarded from the enemy. Resting upon the water-belt and the athwartship or diagonal armor, and following the same direction is a layer of armor usually somewhat thinner which is called the lower case-mate armor; it extends up to the lower edge of the broadside gun ports, and resting upon it in turn is the upper case-mate armor, following the same direction, and forming the protection for the broadside battery. The explosive effect of the modern sh.e.l.l is so tremendous that were one to get through the upper case-mate and explode immediately after entering, it would undoubtedly disable several guns and kill their entire crews; it is, therefore, usual to isolate each broadside gun from its neighbors by light nickel steel bulkheads a couple of inches or so thick, and to prevent the same disastrous result among the guns on the opposite side, a fore-and-aft bulkhead of about the same thickness is placed on the centre line of the ship. Each gun of the broadside battery is thus mounted in a s.p.a.ce by itself somewhat similar to a stall. Abaft the forward turret there is a vertical armored tube resting on the protective deck and at its upper end is the conning tower, from which the ship is worked when in action and which is well safe-guarded.

The tube protects all the mechanical signalling gear running into the conning tower from which communication can be had instantly with any part of the vessel.

To build a battleship that will be practically unsinkable by the gun fire of an enemy it is only necessary to make the water belt armor thick enough to resist the sh.e.l.ls, missiles and projectiles aimed at it. There is another essential that is equally important, and that is the protection of the batteries. The experience of modern battles has made it manifest, that it is impossible for the crew to do their work when exposed to a hail of shot and sh.e.l.l from a modern battery of rapid fire and automatic guns. And so in all more recently built battleships and armored cruisers and gunboats, the protection of broadside batteries and exposed positions has been increased even at the expense of the water-line belt.

Armor plate has been much improved in recent years. During the Civil War the armor on our monitors was only an inch thick. Through such an armor the projectiles of our time would penetrate as easily as a bullet through a pine board. It was the development of gun power and projectiles that called forth the thick armor, but it was soon found that it was impossible for the armor to keep pace with the deadliness of the guns as it was utterly impossible to carry the weight necessary to resist the force of impact. Then came the use of special plates, the compound armor where a hard face to break up the projectile was welded to a softer back to give the necessary strength. This was followed by the steel armor treated by the Harvey process; it was like the compound armor in having a hard face and a soft back, but the plates were made from a single ingot without any welding.

The Harvey process enabled an enormously greater resistance to be obtained with a given weight of armor, but even it has been surpa.s.sed by the Krupp process which enables twelve inches of thickness to give the same resistance as fifteen of Harveyized plates.

The armament or battery of warships is divided into two cla.s.ses, viz., the main and the second batteries. The main battery comprises the heaviest guns on the ship, those firing large sh.e.l.l and armor-piercing projectiles, while the second battery consists of small rapid fire and machine guns for use against torpedo boats or to attack the unprotected or lightly protected gun positions of an enemy. The main battery of our modern battleships consists usually of ten twelve-inch guns, mounted in pairs on turrets in the centre of the ship. In addition to these heavy guns it is usual to mount a number of smaller ones of from five to eight inches diameter of bore on each broadside, although sometimes they are mounted on turrets like the larger guns.

A twelve-inch breech-loading gun, fifty calibers long and weighing eighty-three tons, will propel a sh.e.l.l weighing eight hundred and eighty pounds, by a powder charge of six hundred and twenty-four pounds, at a velocity of over two thousand six hundred and twenty feet per second, giving an energy at the muzzle of over forty thousand foot-tons and is capable of penetrating at the muzzle, forty-five inches of iron.

During the last few years, very large increases have been made in the dimensions, displacements and costs of battleships and armored cruisers as compared with vessels of similar cla.s.ses previously constructed.

Both England and the United States have constructed enormous war vessels within the past decade. The British _Dreadnought_ built in nineteen hundred and five has a draft of thirty-one feet six inches and a displacement of twenty-two thousand and two hundred tons. Later, vessels of the _Dreadnought_ type have a normal draft of twenty-seven feet and a naval displacement of eighteen thousand and six hundred tons. Armored cruisers of the British _Invincible_ cla.s.s have a draft of twenty-six feet and a displacement of seventeen thousand two hundred and fifty tons with a thousand tons of coal on board. These cruisers have engines developing forty-one thousand horse-power.

Within the past two years the United States has turned out a few formidable battleships, which it is claimed surpa.s.s the best of those of any other navy in the world. The _Delaware_ and _North Dakota_ each have a draft of twenty-six feet, eleven inches and a displacement of twenty thousand tons. Great interest attached to the trials of these vessels because they were sister ships fitted with different machinery and it was a matter of much speculation which would develop the greater speed. In addition to the consideration of the battleship as a fighting machine at close quarters, Uncle Sam is trying to have her as fleet as an ocean greyhound should an enemy heave in sight so that the latter would not have much opportunity to show his heels to a broadside. The _Delaware_, which has reciprocating engines, exceeded her contract speed of twenty-one knots on her runs over a measured mile course in Pen.o.bscot Bay on October 22 and 23, 1909. Three runs were made at the rate of nineteen knots, three at 20.50 knots, and five at 21.98 knots.

The _North Dakota_ is furnished with Curtis turbine engines. Here is a comparison of the two ships:

North Delaware Dakota Fastest run over measured mile......... 21.98 22.25 Average of five high runs.............. 21.44 21.83 Full power trial speed................. 21.56 21.64 Full power trial horsepower............ 28,600. 31,400.

Full power trial, coal consumption, tons per day............ 578. 583.

Nineteen-knot trial coal consumption, tons per day....... 315. 295.

Twelve-knot trial coal consumption, tons per day.............111. 105.

The _Florida_, a 21,825 ton boat, was launched from the Brooklyn Navy Yard last May 12. Her sister ship, the _Utah_, took water the previous December at Camden.

Here is a comparison of the _North Dakota_ of 1908 and the _Florida_ of 1910:

N. Dakota Florida Length 518 ft. 9 in. 521 ft. 6 in.

Beam 85 ft. 2-1/2 in. 88 ft. 2-1/2 in.

Draft, Mean 26 ft. 11 in. 28 ft. 6 in.

Displacement 20,000 tons 21,825 tons Coal Supply 2,500 tons 2,500 tons Oil 400 tons 400 tons Belt Armor 12 in. to 8 in. 12 in. to 8 in.

Turret Armor 12 inches 12 inches Battery armor 6 in. 6-1/2 in.

Smoke stack protection 6 inches 9-1/2 inches l2-inch guns Ten Ten 5-inch guns Fourteen Sixteen Speed 21 knots 20.75 knots

The _Florida_ has Parsons turbines working on four shafts and generates 28,000 horse-power.

The United States Navy has planned to lay down next year (1911) two ships of 32,000 tons armed with l4-inch guns, each to cost eighteen million dollars as compared with the $11,000,000 ships of 1910.

The following are to be some of the features of the projected ships, which are to be named the _Arkansas_ and _Wyoming_.

554 ft. long, 93 ft. 3 in. beam, 28 ft. 6 in. draft, 26,000 tons displacement, 28,000 horse-power, 30 1/2 knots speed, 1,650 to 2,500 tons coal supply, armament of twelve l2-inch guns, twenty-one 5-inch, four 3-pounders and two torpedo tubes.