Chapter XV: Part 15

One hundred horse-power; six-cylinder motor; speed, 25 miles per hour; one 10-inch electric searchlight; locomotive bell and hand-operated siren horn; deck turret, one, mounted; nozzle tips, three for deck turret, 1-1/2-inch, 1-3/4-inch, 2-inch; three for tower nozzle, 1-1/2-inch, 1-3/4-inch, 2-inch; hose, one 35-foot length, 4-inch cotton, rubber lined; lanterns, two, fire department standard; axes, two heavy pick back, fire department standard; crowbar, one of steel, held by snaps.]

The Story of the Taking of Food From the Air[52]

What is the greatest discovery of the last twenty-five years? Probably you will say the wireless telegraph, the flying machine, moving pictures or the phonograph, but it would be none of these, according to the _Scientific American_. This publication discussed at great length the subject of what invention of the last twenty-five years was of greatest value to mankind. First place was given not to the wonderful inventions that are so large in the public eye, but to the fixation of nitrogen from the air for fertilizer purposes. Why? Simply because this discovery stands between man and starvation. Other inventions are vastly important, but this one is vital. Looking at it from the broadest view there can be no other decision. The time is here when to feed the world is becoming a more and more difficult problem.

During the past ten years our population has increased at the rate of two per cent per annum, while our crop production has increased only one-half as fast. In six years the number of beef cattle produced in this country has fallen off about five per cent per annum. The cost of foodstuffs recently has been increasing at the rate of five per cent per annum. The hardships experienced by wage-earners, particularly in the United States, have been very great in view of the fact that the cost of food increased more rapidly than wages--at a rate approximately double. The same tendencies apply with some modifications to the clothing of mankind. These facts point to the necessity of increasing the yields both of the food crops and the crops that are used in the making of clothing.

The problem of decreasing the cost of living has been given far more attention abroad than it has in this country, owing to the much greater density of population in the principal nations of Europe. For a long time it has been known that plants require food the same as animals and human beings. Without food plants cannot live and grow, and just to the extent that plant food is present in the soil, to that extent will a crop be produced. The most important of plant foods is nitrogen. While the earth is literally bathed in nitrogen, this element is found to only a very slight degree in the soil. That is to say, the air which we breathe and in which we move is four-fifths nitrogen, yet in the richest soil there is seldom more than one-tenth or two-tenths of one per cent of nitrogen. Put on a wheat crop one pound of nitrogen and you can take off twenty pounds more wheat and forty pounds more straw than you could if you failed to make this application. One pound of nitrogen properly applied to a cornfield will add thirty-five pounds to the crop; one pound of nitrogen will produce one hundred pounds of increase in the potato crop; one pound of nitrogen will produce five pounds of cotton, without any extra labor being devoted to the production of the crop. Nitrogen is the heart and soul of the problem of growing more crops and cheaper crops. Take any nation that produces large crop yields per acre and you will find that the nation that uses the most nitrogen per acre grows the largest crops.

For years the nations of Europe have been depending to a great extent upon supplies of nitrate of soda obtained from Chile, in South America. Germany alone imported nearly a million tons of this salt annually before the war. Then, too, the by-products of many industries furnish a quantity of nitrogen, but all this, it was realized, furnished but a small part of what was required to combat the constantly rising cost of producing food.

For years it was the dream and life-ambition of the world’s greatest scientists to discover how to make the supplies of nitrogen in the air available to plants as food. The only way that this could be done in nature was through the agency of bacteria working on the roots of certain plants, such as clovers, but this process was entirely too slow for practical purposes and could be applied on only a small acreage at one time. The free nitrogen of the air cannot be utilized directly by plants. It must first be converted into some combination with other chemicals, as a solid or liquid, which can be absorbed by the plant. Among others who worked on the problem of fixing atmospheric nitrogen were two German chemists, Doctors Caro and Frank, who found that a compound of calcium and carbon heated to a high temperature would absorb nitrogen and retain it in a form that could be applied to the soil and serve as a food for plants.

This discovery is the basis of the Cyanamid “Atmospheric Nitrogen” industry or the making of fertilizer from the nitrogen in the air. After the discovery was made and tested on the laboratory scale it took several years to put it on a practical basis, as can well be imagined when it is understood what the problems involved were. Besides air this process required as raw materials limestone and coke. The limestone must be burned to quicklime and the quicklime and coke must be fused together to form calcium carbide. Only the most powerful electric furnaces are capable of performing this work. Any other means of heating is far from adequate. For instance, the hottest flame that can be produced by the burning of gas, namely, the oxy-hydrogen blow-pipe flame, can be directed against a stick of burnt lime without doing anything beyond making the lime glow brilliantly, thus producing the calcium or lime-light formerly much used in theaters as a spot-light. In the electric furnaces, however, the lime is heated so powerfully that it actually melts to a liquid, and in this condition it dissolves the coke with which it is mixed and the compound resulting is calcium carbide which can be run off from the interior of the furnace in liquid form.

At the cyanamid plant at Niagara Falls, in Canada, there are seven of these great carbide furnaces, each about fifteen feet long and half as wide and one-third as deep. We all have some idea of how much heat is generated in the ordinary electric arc light such as is used for street lighting. In the carbide furnace the carbon pencil, instead of being six or eight inches long and as large around as your finger, is six feet long and two feet in diameter. There are three of these in each furnace, and when the furnace is in full action it can be imagined that there is a terrific heat generated; in fact, when the fused lime and coke come out of the furnace in the form of molten carbide the brightness of the molten material is so dazzling that one cannot look at it with the naked eyes without injury.

Then there is the problem of producing pure nitrogen gas, that is, separating the eighty per cent of nitrogen in the air from the twenty per cent of oxygen. The latter is the element that we breathe and which passes into the body, there to combine with the impurities resulting from the various life activities. If the nitrogen and the oxygen were both allowed to act upon calcium carbide the oxygen would burn up the carbide before the nitrogen could be fixed in it, hence these two elements must be separated and all other impurities removed so that only chemically pure nitrogen is brought to the calcium carbide for fixation. The separation is accomplished by means of liquid air machines. This industry, therefore, not only utilizes the greatest heat obtainable on a practical scale, but it also utilizes the greatest cold. While the electric furnaces produce a temperature of over 4000° F., or about twice as hot as molten cast-iron, the liquid air machines work at a temperature of 372° F. below zero. The air must first be purified and dried. It is then compressed, cooled while under pressure, and then expanded. The expansion lowers its temperature considerably. If this extra cool air is used for cooling another batch of air under pressure, the latter upon expansion becomes still colder than the first batch expanded. By repeating this operation the final temperature of 372° below zero is reached, at which the air liquifies.

How cold this is can be seen from some simple experiments. For instance, if a dipper full of the liquid air is drawn, in an instant the outside of the dipper is covered with a coating of frost deposited upon it from the surrounding atmosphere. The surrounding air is so much hotter than the liquid air that the liquid boils violently. If a piece of rubber hose is held in the liquid air for eight or ten seconds and then struck with a hammer the rubber flies into pieces just like glass. To dip one’s finger into this liquid air would freeze it solid in a second and would be as disastrous as dipping it in red-hot iron.

When the liquid air is allowed to warm up a little, the nitrogen gas evaporates, while the oxygen remains behind in the liquid. The pure nitrogen then can be pumped into the fixation ovens.

To fix the nitrogen in the carbide it is necessary to cool the latter after it comes from the electric furnaces and grind it to a very fine powder. This powder is then placed in furnaces that look like steel barrels but are three or four times larger than an ordinary barrel. The oven filled with calcium carbide is then electrically heated with a carbon rod running through the center. When the temperature is about as hot as that of molten iron the pure nitrogen gas from the liquid air plant is pumped in and allowed to act on the calcium carbide for about a day and a half. When the carbide has absorbed all it will absorb the crude cyanamid formed is removed from the oven as a single large cake which is run through pulverizing drums and then put through an elaborate process of refinement and finally bagged for shipment in carload lots to fertilizer factories throughout the country.

The fertilizer manufacturers mix the cyanamid with other ingredients to make a balanced plant food and so ship it to farmers for feeding their crops. In 1914 7,500,000 tons of fertilizer worth $175,000,000 were consumed in this country. This seems like a large quantity, but it allows only a scanty application per acre cultivated. Germany, on one-fourth of our cultivated acreage, uses almost twice as much fertilizer as the entire United States. As a consequence she raises 30 bushels of wheat where we average 14 bushels per acre; 52 bushels of oats where we average 30; and 196 bushels of potatoes per acre where we raise 97 bushels per acre. The explanation is simple, German farmers pay only about one-half as much for their plant food as American farmers pay. Where the German farmer gains $2.00 to $3.00 increase in crop from fertilizer that costs him $1.00 the American farmer pays $2.00 for the same fertilizer, which leaves him less profit and less incentive to use fertilizer.

FOREVER RUSHING AND FOREVER WONDERFUL

Niagara Falls from Prospect Point on the American side, looking southwest, across and up the stream. The American Falls may be seen in the foreground rushing past to make their plunge of 165 feet to the rocks below.]

The air-nitrogen industry in the United States is said to be considerably handicapped because the large quantities of electricity required are not available at a low enough price. There are excellent water-power sites in the United States sufficient to furnish many times the required power, but the existing water-power laws are so burdensome that investors will not put their money into power development except on such high terms that the power is much dearer than it can be bought for in other countries. Practically every civilized country in the world, except the United States, had one or more cyanamid factories in 1916. These include Germany, Austria-Hungary, Great Britain, France, Italy, Switzerland, Norway, Sweden, Japan and Canada. Their combined output is about 1,000,000 tons per annum. The cyanamid plant at Niagara Falls, Ontario, which was established in 1909, with a capacity of 10,000 tons, had a capacity of 64,000 tons per annum in 1916. It utilizes about 30,000 electrical horse-power twenty-four hours a day, and three hundred and sixty-five days a year. Germany, at the beginning of the war, produced about 30,000 tons of cyanamid; in 1916 she was making 600,000 tons a year. She is using it both to grow crops and to make explosives for her guns.

At the time the war broke out, in August, 1914, Germany was importing nearly one million tons of nitrate of soda per annum from Chile, South America. This supply was immediately cut off by enemy fleets. Not only was her agriculture thereby threatened with a great decrease in crop production but her supply of military explosives was also threatened. Professor Dr. Lemmermann, a famous German scientist, advised his government that unless the nitrogen shortage were made good the resulting crop shortage would amount to 3,300,000 tons of grain. But if people require food, guns require powder, and no powder can be made without nitric acid. It has been reported on good authority that Germany has consumed one and one-third million pounds of powder a day during the war. To make one pound of powder requires one and one-half pounds of nitric acid, so that Germany required for military purposes 2,000,000 pounds of nitric acid per day. From her coke ovens she indeed could derive some nitrogen, but this actually furnished only about one-fifth of her total requirements. For the other four-fifths she turned to atmospheric nitrogen. For it is also true that this remarkable compound, cyanamid, which is a food for plants, can be decomposed by high-steam pressure into the purest ammonia gas. The ammonia can in turn be oxidized to nitric acid, which is the basis of all explosives. Without the fixation of atmospheric nitrogen on a tremendous scale there is no doubt that Germany would have become helpless before her enemies within a year after the war began, for no nation can fight unless it has sufficient food for its people and powder for its guns.

Eleven turbine generators in the Niagara Falls Power House, each set developing 5,000 horse-power.]

The preservation of food is also dependent on ammonia, which produces the refrigerating effect in the numerous cold storage houses and artificial ice plants in this country. In the cold storage plants alone the cold produced by means of ammonia is equal to 750,000 tons of ice consumed per day, while 25,000,000 tons of artificial ice are produced and sold as such per annum. Cyanamid ammonia gas is especially valuable for this purpose on account of its high degree of purity.

Then, too, the ammonia gas can be fixed in any acid desired, for instance, in phosphoric acid, making ammonium phosphate, a fertilizer of unusual merit, or ammonium sulphate, another fertilizer, or ammonium nitrate, an explosive. So, for peace or war, the fixation of atmospheric nitrogen has become a tremendous factor in the life of nations.

If the United States should be forced into war with a foreign power it would be a simple matter for an enemy fleet to cut off our large importations of nitrate of soda from Chile. These amount to about 700,000 tons per annum in normal times and at present about 900,000 tons per annum. In other words, we would be short just this quantity of nitrogen in addition to the quantity that would be required by the government for the manufacture of military explosives. It has been suggested that our coke-oven industry could be expanded to furnish a large part of this requirement, but even with the largest expansion considered practical by the coke-oven people within the next several years, the coke ovens would not be able to supply even one-third of our requirements, thus leaving a large balance which could be furnished only by the establishment of a large nitrogen industry in this country.

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The expression “The King can do no wrong” has been widely used since it first caught people’s fancy at the time of the explanation, made in England, that the Ministers, and not the King, were responsible for mistakes of government.

What is a Drawbridge Like Today?

We have all read of the castles in olden days into which the owner could retire and raise a drawbridge across a ditch, thus putting a barrier in the way of his enemies.

That old style drawbridge, with, of course, many improvements, has been adopted in these modern times to use in permitting navigable rivers and channels to be crossed by railroads and other kinds of transportation, without preventing the passage of vessels up and down the rivers.

Modern drawbridges across rivers, canals, the entrances of docks, etc., are generally made to open vertically, and the movable portion is called a bascule, balance or lifting bridge; a turning, swivel or swing bridge; or a rolling bridge, in accordance with the mode in which it is made to open.

Swing bridges are usually divided into two parts meeting in the middle, and each moved on pivots on the opposite sides of the channel, or they may move as a whole on a pivot in the middle of the channel.

Rolling bridges are suspended from a structure high above the water, and are propelled backwards and forwards by means of rollers.

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The advantages of this type of bridge are that the entire width of the channel is available for navigation, and the draw may be opened and closed more readily than the swing type.]

The Story of a Deep Sea Monster[54]

The early day was blue and silver; one of those colorful mornings peculiar to southern Florida. Sandwiched between the earth and the turquoise sky, the Atlantic lay gleaming like a huge silver wafer in the sunlight. Not the faintest suggestion of a ripple marred its shining surface.

Suddenly out of the stillness of the silver water a huge black fin was lifted, and a little group of men lounging on the deck of an idle fishing craft drew near the rail and used their glasses.

“Shark,” remarked the captain pleasantly after a moment’s scrutiny. “Who wants to go out with me for a little fun?”

The hastily lowered lifeboat pointed a slim nose toward the large black shape thrashing about in the shallow water. Three men were in the boat--Captain Charles H. Thompson of the yacht “Samoa,” one of the yacht’s crew, and a winter visitor to southern Florida. As they drew near, the sailor took one look at the gigantic creature and yelled to the captain:

“For heaven’s sake, man, don’t harpoon that thing; we will be crushed like an egg shell!”

Poised in the bow of the boat, harpoon in hand, stood the captain, and as they drew alongside there was a flash; the steel glittered for a moment in the sunlight, then sank into the huge black bulk. Simultaneously the little boat spun around and shot out toward the Gulf Stream like an agitated and very erratic rocket, flinging great sheets of spray high into the air as it sped.

Thus began a thirty-nine hours’ ride filled with wildest thrills, during which time Captain Thompson battled with the fish, the sailor bailed the boat unceasingly, lest they be swamped, and the tourist raised an anxious and eloquent voice to high heaven. The men were without food the entire time, sharing only a small bottle of water among them.

The news of the struggle spread rapidly, and soon hundreds of interested spectators gathered on the trestle of the East Coast sea-extension railway. Scores of times the men in the boat escaped death only by a miracle, as the wildly thrashing black tail missed them but by a hair’s breadth. Finally, after two days and one night, the monster was worn out, and the triumphant captor managed to fasten it to the trestle work on Knight’s Key, where, after a few hours’ rest, it wigwagged a festive tail, smashing the large pilings as though they were toothpicks. After another battle the fish was firmly tied up once more, this time to the yacht “Samoa;” and again it waved a wicked tail, disabling the thirty-ton yacht by smashing her propeller and breaking the cables. A tug was then summoned, and the big fellow was towed one hundred and ten miles to Miami, Florida, where it was viewed by thousands of people.

Five harpoons and one hundred and fifty-one bullets were used in subduing the monster, and it took five days to finally kill it.

It was thought at first the creature was a whale, but later it was classified as a fish, for it breathed through gills of which there were five in number. Upon careful examination it seemed probable that it was a baby of its species, as the backbone was of a cartilaginous nature, a condition found only in a young creature; in a full-grown one this develops into true bone. That it was a deep-sea fish was indicated by the small eye, which was about the size of a silver dollar. The pressure of the water is so great at the bottom of the ocean that were the eyes large they would be ruptured. That the pupil did not dilate and contract seems additional proof that the fish must have lived at a depth of probably fifteen hundred or two thousand feet, where there is little light.

DEEP SEA MONSTER CAPTURED OFF FLORIDA

So far as the scientific world is concerned, this is the only fish of its kind ever captured. Length, 45 feet; weight, 30,000 pounds; circumference, 23 feet 9 inches; diameter 8 feet 3 inches; mouth (open), 31 inches; mouth, 38 inches wide; mouth, 43 inches deep; tongue, 40 inches long; several thousand teeth; hide, three inches thick, no scales; had swallowed an animal weighing 1,500 pounds; tail measures 10 feet from tip to tip; pectoral fin, 5 feet long, 3 feet wide; dorsal fin, 3 feet long, 2 feet 9 inches wide; gills, 4 feet; the liver weighed 1,700 pounds.]

It is generally believed that some volcanic eruption drove the fish to the surface where, owing to the difference in water pressure, the swim-bladders burst, making it impossible for him to return to his level.

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What is an Armored Railway Car Like?

The armored car shown in this picture is the first of a new type of armored car to be constructed by the United States. It was designed under the direction of the Board of Engineers of the U. S. Army, and was constructed by the Standard Steel Car Company, Pittsburgh, Pa., at their Hammond, Ind., plant. The car was designed and built within twenty-seven days.

_Courtesy of the Railway Age Gazette and Standard Steel Car Co._]

The car consists of heavy steel plate structure, erected upon a flat car of standard type. The interior is divided into three compartments. The end compartments are for use of troops operating machine guns and rifles through the port-holes shown on side of car. The center compartment, which is not the full height of the car, is used for ammunition storage, and is capable of holding a large quantity of ammunition, either for small arms or for the rapid-fire gun which is mounted on top of the car. The rapid-fire gun here shown is a model of a three-inch field gun mounted upon a special carriage. The well in which the gun is located may also be used as a fighting top for troops armed with rifles or machine guns.

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This car is known as a light-armored car. It is armed with a three-inch rapid-fire gun, two machine guns and any number of rifles which the troops occupying it may carry. The service for which this car is intended is primarily to guard railroads and depots adjacent to railroads. It is not ordinarily to be employed in aggressive movements. In effect, it is a movable block-house which may be used at any point along the line, or it may be used as a retreat for troops when necessary. It may also be used for transporting troops past danger points, and for transporting explosives or other perishable material which might be damaged by fire from the ends. The car as constructed weighs 86,200 pounds. It is 47 feet long, 9 feet 3 inches wide, and 7 feet high at the ends. When used for transportation of troops, it will accommodate a company of infantry seated on camp stools or benches. When used for patrol purposes, there would not be more than twelve men in the car, to operate the rapid-fire gun and machine guns.

_Courtesy of the Railway Age Gazette and Standard Steel Car Co._]

The car was shipped to the Sandy Hook proving grounds to be equipped with rapid-fire guns and ammunition and thoroughly tested and inspected by the Engineer and Ordnance Officer of the U. S. Army.

What is an “Electric Eel”?

This is an eel abundant in the fresh waters of Brazil and the Guianas, which possesses organs capable of developing a strong electric current and thus of giving a violent shock to any one touching the eels. These organs replace the lower muscles along the sides of the tail. The eels can be taken by driving horses into the water to be shocked and seizing them when thus weakened.

The Story of Salt[56]

Salt is a chemical compound composed of two elements, sodium and chlorine. Chemically it is known as sodium chloride.

It is one of the things which comes into our lives daily, perhaps more than any other, with the exception of water. Probably no other thing than water is used more by all civilized people than salt.

Nature provides salt for us in three different forms. First, in sea water in solution; second, in salt springs; and third, in the form of salt rock.

From time immemorial man has obtained salt from sea water. This is still being done on our sea coasts, but the salt obtained by evaporating the water is very crude and usually contains many impurities.

It has been possible to obtain a large supply of salt from what are known as salt springs. These springs are usually the result of water flowing over a deposit of salt rock. The amount of salt obtained from evaporating this spring water is, however, so small that salt springs are an impractical source of supply when it comes to making salt for commercial purposes.

Rock salt forms the most common and practical source of supply. It is found in all parts of the world and reasonably near the surface. The deposit is said to be what is left of ancient salt seas. In the United States the largest deposits of salt are found in the states of Michigan, New York, Ohio, Utah, Louisiana, Kansas, Texas and California. The above-mentioned states are the largest producers of salt in this country.

One of the largest sources of salt supply in Europe is at Wielizka in Poland. This deposit of salt is said to be the largest in the world, the bed of salt rock being 500 miles long, 20 miles wide and 1,200 feet thick. Some of the salt mines in Poland are so extensive that it is said some of the miners spend all of their lives in them, never coming to the surface of the earth.

Most of the deposits of salt rock contain impurities which need to be removed before the salt is fit for use commercially; however, some deposits show a very pure salt rock and when ground up this rock salt is suitable for table use. In general, however, the salt made from crude salt rock is only fit for the crudest commercial uses. The most common impurity is gypsum and it is necessary to remove this gypsum before the salt can be considered pure.

SALT BEDS NEAR SALT LAKE CITY

These extensive salt beds about eighteen miles from Salt Lake City are part of the deposit left when Lake Bonneville dwindled to Great Salt Lake.]

The general way of obtaining salt from the earth is by means of salt wells. These wells are drilled in the same way that wells are bored for oil and gas. A pipe about six inches in diameter is lowered to the surface of the salt rock and then an inside pipe is put down, water is forced down between the two pipes and the pressure exerted brings up the dissolved rock or salt brine through the inside pipe.

As the salt brine reaches the surface the salt is extracted from it in various ways. At present the crude open-pan system, where the brine was poured into open pans and fires were built below the pans, is almost obsolete. The most practical methods of refining salt today are known as the Grainer, Vacuum Pan and Alberger systems.

The Grainer system is similar in its operation to the old open-pan system. The brine is run through long, shallow tanks and the heat is applied through steam pipes inside of the pan. The salt settles to the bottom of the pan and large rakes operated either by hand or machinery collect the salt.

In the Vacuum Pan process tiny cubes of salt are formed and settle to the bottom of the pan in which a vacuum has been created. The salt is then drained out and is ready for drying.

Variations of the two above processes make possible the production of certain grades of table salt. Oftentimes the brine is relieved of impurities through the action of certain chemicals. In some instances a chemical known as “barium chloride” is used, but the wisdom of this process has been much questioned, owing to the fact that barium chloride is a deadly poison.

The Alberger system of salt manufacture is a mechanical process which subjects the salt brine to a much higher temperature and removes the impurities by means of mechanical filters. This process is known to make a very pure salt and has been used for some time as a practical method for manufacturing high-grade dairy and table salt. Unlike the other two common methods of making salt, it forms tiny salt flakes instead of the usual cubes or lumps.

After manufacturers obtain the salt from the brine they usually put it through drying processes. After drying, the salt is sifted and the fine table salt is separated from the coarser products. When salt is sifted it is ready for packing in bags or packages suitable for shipment to the consumer.

According to recent government reports, it is estimated that the average consumption of salt per capita for all purposes is about 100 pounds per year. The salt industry is now said to have reached a very stable basis and the demand for salt in the United States is practically all supplied by American manufacturers. Salt can be put to a great many uses in addition to the usual requirements for table and cooking. It is used by food manufacturers and performs highly important functions in certain commercial fields.

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Why do We Call it “Denatured Alcohol”?

Under a law passed by the United States Congress in 1907, on alcohol intended for use as fuel or for illuminating purposes, or other mechanical employment, the internal tax need not be paid. But to avoid taxation it must be rendered unfit for drinking by the addition of such unpalatable substances as wood alcohol, pyridin, benzola, sulphuric ether or animal oil. Thus treated, it is spoken of as denatured.

What is the Difference Between a Cruiser and a Battleship?

A cruiser is a vessel built to secure speed and fuel capacity at the expense of armor and battery strength.

The modern cruiser may be regarded as the offspring of the frigate of the eighteenth and nineteenth centuries. The later construction has been designed for a minimum speed of twenty-five knots an hour, with a possible attainment of thirty knots or over, under favorable conditions.

The battleship and one form of cruiser were evolved from the conflicting opinions of two opposite schools of design. The battleship is the expression of the thoughts of those who stood for extremely developed battery power, great thickness of armor plate, and moderate speed. The cruiser is the result of the triumph of those who contended for high speed at the sacrifice of heavy armor protection and excessive battery strength.

The armored cruiser was the particular development of the antagonistic views prevailing among naval architects. The type of this class in the United States navy was the “Brooklyn,” which figured prominently in the war with Spain in 1898.

Recently the armored cruiser has been superseded by the battle cruiser. The armor protection in this type of ship is much lower than that of the battleship, while the ordnance, on the other hand, is practically the same. High speed, wide radius of action and great battery strength are the characteristics of this type; and to meet these requirements the battle cruiser is planned of a size considerably larger than the battleship.

The protected cruiser is a later development of naval construction. Its distinguishing features are certain modifications in the distribution of the mass of protective armor of the ship.

Light cruisers are vessels of from 1,500 to 7,500 tons, used in scouting, as commerce destroyers, etc. They are outside the armored class.

This most dramatic photograph of the Great North Sea Battle, in which the British fleet was victor, January 24, 1915, shows the death agony of the German cruiser “Bluecher” just as she turned turtle and sank. The ship is shown lying on her side with her machinery and armament shot into masses of twisted iron and steel, great fires raging forward, amidship and aft.

_Copyright by the International News Service._]

UNITED STATES BATTLESHIP “OKLAHOMA”

One of the latest types of super-dreadnaught is here shown, racing along at 20-1/2 knots an hour on a speed test. This great warship is a sister-ship of the “Nevada.” Her displacement is 27,500 tons, her engines develop 28,000 horsepower and she is armed with ten 14-inch guns in her four turrets, twenty-one 5-inch and four 3-pounders, together with four 21-inch Torpedo Tubes. She cost over $6,000,000.]

The Story of the Growth of the Motor Truck[57]

While exact dates are not easily obtainable, it is thought to be quite within the bounds of reasonable accuracy to say that the motor truck only began to be recognized as a practical vehicle for commercial purposes in 1905.

Today motor vehicles, both pleasure and commercial, are such a common sight in every city and town, and even throughout the rural districts, that one can scarcely believe that they were a novelty such a little time ago.

The statistics show, however, that in 1906 the total registrations of both pleasure and commercial vehicles, as reported by the various states, was 48,000--about one month’s production today of one well-known pleasure-car maker.

In 1915 the registrations totaled nearly 2,500,000, and every day has added to the number.

It can be truthfully said that the pleasure car is the father of the truck or commercial car.

The application of the internal combustion engine to the use of propelling vehicles was the beginning of a new era in that world. The idea, born, one might say, with the new century, has already done more to revolutionize transportation than all of the inventions of all the centuries that have gone before.

The automobile, first looked upon as a freak, then “a rich man’s plaything,” has in a few years come to be recognized as a necessity, and literally millions of people are employed in its production and dependent on the industry for support.

To trace the ramifications of the industry back through the mills, mines and factories that produce the iron, steel, copper, brass, zinc, aluminum, lead, leather, lumber, glass, celluloid, etc., would make a long and interesting story, but this chapter deals with the motor vehicle as a commercial car or truck and the part it is playing in transportation of the world’s goods.

While the first commercial vehicles to come into use were electrically propelled, and while the electric truck has become a factor in the large cities, the gasoline power vehicles are, as yet, the dominant factor.

At the first, business men were slow to take up the use of trucks for delivery and hauling purposes and one of the specialties of early factories was the making of “sight-seeing” cars which were sold to enterprising individuals in cities and summer resorts for the purpose of showing visitors the sights. These wagons became popular throughout the country and are still being used in many places.

Little by little, however, progressive business men saw the advantages to be gained by motor delivery and the motor truck began to gain favor. Several of the pleasure-car manufacturers took advantage of the awakening interest and added a commercial vehicle section to their plants.

Others began to see visions of the day when horses would no longer be used for other than strictly farm work, and motor-truck factories sprang up here and there, even faster than pleasure-car plants.

Like the seed mentioned in the parable of the sower, some fell on good ground and grew to produce a bountiful harvest, but many withered by the wayside.

In the early days of the motor-truck industry men bought the finished vehicle, but later on the practice of selling chassis only became popular, and while today some manufacturers cater to the body trade, a large percentage of trucks are sold to the purchaser without the body, this being built by a local builder, the truck manufacturer furnishing a body builder’s blue-print.

As in everything else, it has taken time to overcome the faults of the early trucks. Most all trucks above 1,500 pounds capacity are equipped with solid rubber tires, and while the solid rubber tires and the springs on the trucks give a great deal of resiliency, it was discovered that the steady pounding over all kinds of pavements soon racked a truck to pieces and that pleasure-car practice could not be followed successively in building motor trucks.

In the earlier days truck buyers made many mistakes in selecting the size or capacity of trucks. Some made the mistake of buying trucks too light for their work. Others selected trucks large enough to provide for exceptional or emergency loads, and would, for example, buy a truck of 3-1/2-tons capacity when 90 per cent of their hauling was loads not exceeding 1-1/2 or 2 tons. Thus they not only had a greater investment than necessary in the truck itself, but were paying an exclusive charge in the way of operating costs and depreciation.

But the experimental days have passed, both in the manufacture of motor trucks and in their adaption to various lines of work. If the buyer has not determined by experience and investigation the kind and capacity of truck he should use, the older manufacturers are able to step in and analyze the work to be done and to intelligently recommend to the buyer what he should have.

That motor trucks not only furnish cheaper transportation than horse-drawn vehicles, but greatly extend the radius of operation, is quite generally conceded. This is shown by the enormous increase in the demand for motor trucks in all lines of business where goods of any kind are to be moved over any considerable distance.

With motor trucks, merchants have extended their deliveries to reach territory they could not touch under the horse-delivery system.

Market gardeners, who must have their product in the city markets early and have it fresh, can now sell their high-priced land adjoining the cities and go miles back in the country where as good ground can be bought for from one-tenth to one-fourth the price their suburban property will bring--and still be closer to market with their motor trucks than they were before with their horses.

Contractors can transport material long distances and save both time and money. Dairymen collect milk over a radius of thirty or forty miles and get it to market fresh. Freight and passenger lines are possible with motor trucks where a steam railroad or trolley system would not be practicable.

In short, the motor truck is revolutionizing transportation. As made today by the leading manufacturers, it is simple, durable and easy to operate and care for.

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What is a Diving Bell?

Diving, aside from the pleasure afforded to good swimmers, is important in many different industries, particularly in fishing for pearls, corals, sponges, etc.

Without the aid of artificial appliances a skilful diver may remain under water for two, or even three minutes; accounts of longer periods are doubtful or absurd.

The Vessel steams to place of working and is moored by the Steam Winches A A at bow and stern to buoys, the Bucket Ladder B is then lowered by steam power, and thereafter Buckets set in motion by gearing C C. The depth of water at which the Bucket Ladder dredges is regulated by the Hoisting Shears and Chain Barrel D D, driven by shafting E E from the Engines. The Buckets discharge the material by the shoot F into the Hopper G. The dredged material is discharged by the doors of the Hopper being opened by the Lifting Chains H H. These doors are hinged on to the side of Vessel, and suspended at centre by the Lifting Chains, which are connected to geared Crab Winches I I.]

All the appliances are worked by steam, rendering manual labour unnecessary. A is the Bell, which is raised and lowered by means of the Chain and Steam Winch B. _c c_ are Seats within the Bell; _d d_, Footboards. E, Air-pipe entering the Bell at _f_, the air being supplied by Air-pump G driven by the Engine H. J is a Steam Crane for raising or lowering material. K K, Steam Winches for working moorings and shifting position of the barge.]

Various methods have been proposed and engines contrived to render diving more safe and easy. The great object in all these is to furnish the diver with fresh air, without which he must either make but a short stay under water or perish.

Diving bells have been used very effectively. A diving bell is a contrivance for the purpose of enabling persons to descend, and to remain, below the surface of water for a length of time, to perform various operations, such as examining the foundations of bridges, blasting rocks, recovering treasure from sunken vessels, etc.

Diving bells have been made of various forms, more especially in that of a bell or hollow truncated cone, with the smaller end closed, and the larger one, which is placed lowermost, open.

The air contained within these vessels prevents them from being filled with water on submersion, so that the diver may descend in them and breathe freely for a long time provided he can be furnished with a new supply of fresh air when the contained air becomes vitiated by respiration. This is done by means of a flexible tube, through which air is forced into the bell.

A form, called the “nautilus,” has been invented which enables the occupants, and not the attendants above, to raise or sink the bell, move it about at pleasure, or raise great weights with it and deposit them in any desired spot.

How are Harbors Dredged Out?

There are several forms of mechanical, power-operated dredges. One of the most common is the “clam-shell” dredge, consisting of a pair of large, heavy iron jaws, hinged at the back, in general form resembling a pair of huge clam shells. This with its attachments is called the grapple. In operation it is lowered with open jaws, and by its own weight digs into the ground that is to be excavated. Traction is then made on the chains controlling the jaws, which close; the grapple is hoisted to the surface and its contents discharged into scows alongside the dredge.

The dipper dredge, an exclusively American type, has a bucket rigidly attached to a projecting timber arm. In operation the bucket is lowered and made to take a curving upward cut, thus dipping up the bottom material, which is discharged through the hinged bottom of the bucket. The pump or suction dredge operates by means of a flexible pipe connected with a powerful centrifugal pump. The pipe is lowered into contact with the bottom to be excavated and the material is pumped into hopper barges or into a hopper-well in the dredge itself.

The center ladder bucket dredge operates by means of an endless chain of buckets moving over an inclined plane, which in structure is a strong iron ladder, one end of which is lowered to the sea bottom. The steel buckets scoop up the material at the bottom of the ladder, which they then ascend, and are discharged by becoming inverted at the upper end of the ladder. This dredge is the only one found satisfactory in excavating rock.

How is a Razor Blade Made?

The best scissors, penknives, razors and lancets are made of cast steel. Table knives, plane irons and chisels of a very superior kind are made of shear steel, while common steel is wrought up into ordinary cutlery.

In making razors, the workman, being furnished with a bar of cast steel, forges his blade from it. After being brought into true shape by filing, the blade is exposed to a cherry-red heat and instantly quenched in cold water. The blade is then tempered by first brightening one side and then heating it over a fire free from flame and smoke, until the bright surface acquires a straw color (or it may be tempered differently). It is again quenched, and is then ready for being ground and polished.

The Story of the Tunnels Under the Hudson River[58]

The building of the Hudson River tunnels was probably one of the most daring engineering feats ever accomplished. As is well known, the Hudson River, for the length of Manhattan Island, is approximately a mile wide, reducing in width at the Palisades north of Hoboken. In consequence of the unusual geographical situation, all trunk lines and other transit facilities in New Jersey terminate on the westerly shore of the Hudson, and passengers were of necessity compelled to use ferries to reach New York. A conservative estimate, which was confirmed by various counts, indicates that, prior to the construction of the tubes, the annual passenger traffic between New Jersey and New York was 125,000,000, and to handle this great volume of traffic the transportation companies assembled in the Hudson River a fleet of rapid ferry boats and maintained them up to the highest and most modern standards. But this very expeditious ferry service was not enough, and for many years there was a demand for facilities for more rapid transportation of the tremendous population residing in the suburban district of New Jersey tributary to New York City. As far back as 1873, a company had been organized to construct a tunnel under the river, but had met with numerous and most discouraging difficulties and obstacles, so that it was finally compelled to abandon the work, although it succeeded in building a considerable length of structure. Efforts were made at various times after that date to revive the work, with little or no results. In 1902 it was resumed, however, and a few years later was pushed to a successful end.

During the undertaking, more than 40,000 men were engaged in air-pressure work and there were many thousand more who did not work under air pressure. This vast army of men consisted of all nationalities and all grades and conditions of labor. The skilled tunnel workmen are men of character and ability, usually young, of good intelligence and sound of body, without a streak of fear or cowardice in their makeup. All of those characteristics are essential to under-water air-pressure work.

As is quite generally known, air pressure and tunnel shields were used in all of the under-water work. It might be well to here correct the misconception which exists in the minds of many, that the use of air pressure for such purposes is something comparatively new. This is not the case. The use of air pressure was a very early invention, and it is a matter of record that in 1830, Admiral Cochrane, afterwards Lord Dundonald, was granted letters patent for the use of air pressure in tunnel construction. The modern engineer has merely developed the art to a high degree.

The method of construction used in the Hudson River tunnels has been designated the “shield method.” In this type of construction, the primary part of the tunnel structure consists of an iron shell, formed of segmental rings, bolted together through inside flanges, and forming a large articulated pipe or tube, circular in section. This iron shell is put in place segmentally by means of a shield, an ingenious mechanism which both protects the work under construction and assists in the building of the iron shell.

Hudson River Tubes of the Hudson & Manhattan R. R. Co.]

A tunneling shield consists essentially of a tube or cylinder slightly larger in diameter than the tunnel it is intended to build, which slides over the exterior of the finished lining like the tubes of a telescope. The front end of this cylindrical shield is provided with a diaphragm or bulkhead in which are apertures which may be opened or closed at will. Behind this diaphragm are placed a number of hydraulic jacks, so arranged that by thrusting against the last erected iron ring the entire shield is pushed forward. The hind end of the shield is simply a continuation of the cylinder which forms the front end, and this hind end, or tail, always overlaps the last few feet of the built-up iron-shell tunnel.

When the openings in the bulkhead are closed, the tunnel is protected from the inrush of water or soft ground, and the openings may be so regulated that control is maintained over the material passed through. After a ring of iron lining has been erected within the tail of the shield, excavation is carried out ahead. When sufficient excavation has been taken out, the jacks are again extended, thus pushing the shield ahead, and another ring of iron is erected as before.

For the erection of these heavy plates, a hydraulic swinging arm, called the “Erector,” is mounted, either on the shield itself or on an independent erector platform, according to conditions. This erector approaches closely the faculties of the human arm. It is hydraulically operated and can be moved in any desired direction. This method of construction can be followed in almost every kind of ground that can be met with, and it is especially valuable in dealing with soft, wet grounds. In passing through materials saturated with water, the shield is assisted by using compressed air in the working chamber.

The employment of compressed air under such conditions is really a rather simple thing in itself, and means merely that the pressure of air in the chamber where men are working is maintained at a point sufficient to offset the pressure of the hydrostatic head of water and thereby prevent its inflow. A crude comparison may be made by saying that if the ceiling of a room was weak and threatening to fall--if we filled the room with sufficient pressure of air, it would support the ceiling and prevent it falling in. In tunnel work, air is supplied under compression from the mechanical construction plant located on the surface, and the pressure of air maintained in the working chamber is determined by the depth of the work below tide level, as the hydrostatic head increases with the depth.

Control of air pressure is never entrusted to any but the most reliable, competent and experienced man, as it is of the utmost importance that air pressure be maintained properly. The first impulse of an inexperienced man, should he notice an inrush of water, would be to increase the air pressure, which might be a very dangerous thing to do. An experienced man, however, would very likely first lower his pressure in such an emergency, and then put up with the nuisance and difficulty of having a good deal of water in his working chamber. By doing this, he would permit the greater external pressure to squeeze the soil into the leaking pockets and thereby choke the leak.

To improperly or inopportunely raise the air pressure would be quite likely to result in the air blowing a hole through the roof of the tunnel heading, allowing all air pressure to escape, and permitting an uncontrollable volume of water to rush in and flood the work.