Prehistoric Time—Earliest Records—Discoveries in Bible Lands—American Explorations.
For the earliest civilization and culture we must go to that part of the world, which according to the general belief, is the cradle of the human race. The civilization of the Mesopotamian plain is not only the oldest but the first where man settled in great city communities, under an orderly government, with a developed religion, practicing agriculture, erecting dwellings and using a syllabified writing. All modern civilization had its source there. For 6,000 years the cuneiform or wedge-shaped writing of the Assyrians was the literary script of the whole civilized ancient world, from the shores of the Mediterranean to India and even to China, for Chinese civilization, old as it is, is based upon that which obtained in Mesopotamia. In Egypt, too, at an early date was a high form of neolithic civilization. Six thousand years before Christ, a white-skinned, blond-haired, blue-eyed race dwelt there, built towns, carried on commerce, made woven linen cloth, tanned leather, formed beautiful pottery without the wheel, cut stone with the lathe and designed ornaments from ivory and metals. These were succeeded by another great race which probably migrated into Egypt from Arabia. Among them were warriors and administrators, fine mechanics, artisans, artists and sculptors. They left us the Pyramids and other magnificent monumental tombs and great masses of architecture and sculptured columns. Of course, they declined and passed away, as all things human must; but they left behind them evidences to tell of their prestige and power.
The scientists and geologists of our day are busy unearthing the remains of the ancient peoples of the Eastern world, who started the waves of civilization both to the Orient and the Occident. Vast stores of knowledge are being accumulated and almost every day sees some ancient treasure trove brought to light. Especially in Biblical lands is the explorer busy unearthing the relics of the mighty past and throwing a flood of light upon incidents and scenes long covered by the dust of centuries.
Babylon, the mightiest city of ancient times, celebrated in the Bible and in the earliest human records as the greatest centre of sensual splendor and sinful luxury the world has ever seen, is at last being explored in the most thorough manner by the German Oriental Society, of which the Kaiser is patron. Babylon rose to its greatest glory under Nebuchadnezzar, the most famous monarch of the Babylonian Empire. At that period it was the great centre of arts, learning and science, astronomy and astrology being patronized by the Babylonian kings. The city finally came to a terrible end under Belshazzar, as related in the Bible. The palace of the impious king has been uncovered and its great piles of masonry laid bare. The great hall, where the young prophet Daniel read the handwriting on the wall, can now be seen. The palace stood on elevated ground and was of majestic dimensions. A winding chariot road led up to it. The lower part was of stone and the upper of burned bricks. All around on the outside ran artistic sculptures of men hunting animals. The doors were massive and of bronze and swung inward, between colossal figures of winged bulls. From the hall a stairway led to the throne room of the King, which was decorated with gold and precious stones and finished in many colors. The hall in which the infamous banquet was held was 140 feet by 40 feet. For a ceiling it was spanned by the cedars of Lebanon which exhaled a sweet perfume. At night a myriad lights lent brilliancy to the scene. There were over 200 rooms all gorgeously furnished, most of them devoted to the inmates of the king's harem. The ruins as seen to-day impress the visitor and excite wonder and admiration.
The Germans have also uncovered the great gate of Ishtar at Babylon, which Nebuchadnezzar erected in honor of the goddess of love and war, the most renowned of all the mythical deities of the Babylonian Pantheon. It is a double gateway with interior chambers, flanked by massive towers and was erected at the end of the Sacred Road at the northeast corner of the palace. Its most unique feature consists in the scheme of decoration on its walls, which are covered with row upon row of bulls and dragons represented in the brilliant enamelled bricks. Some of these creatures are flat and others raised in relief. Those in relief are being taken apart to be sent to Berlin, where they will be again put together for exhibition.
The friezes on this gate of Ishtar are among the finest examples of enamelled brickwork that have been uncovered and take their place beside "the Lion Frieze" from Sargon's palace at Khorsabad and the still more famous "Frieze of Arches of King Darius" in the Paris Louvre.
The German party have already established the claim of Herodotus as to the thickness of the walls of the city. Herodotus estimated them at two hundred royal cubits (348 feet) high and fifty royal cubits (86-1/2 feet) thick. At places they have been found even thicker. So wide were they that on the top a four-horse chariot could easily turn.
The hanging gardens of Babylon, said to have been built to please Amytis the consort of Nebuchadnezzar, were classed as among the Seven Wonders of the World. Terraces were constructed 450 feet square, of huge stones which cost millions in that stoneless country. These were supported by countless columns, the tallest of which were 160 feet high. On top of the stones were layers of brick, cemented and covered with pitch, over which was poured a layer of lead to make all absolutely water-tight. Finally, on the top of this, earth was spread to such a depth that the largest trees had room for their roots. The trees were planted in rows forming squares and between them were flower gardens. In fact, these gardens constituted an Eden in the air, which has never since been duplicated.
New discoveries have been recently made concerning the Tower of Babel, the construction of which, as described in the Book of Genesis, is one of the most remarkable occurrences of the first stage of the world's history. It has been found that the tower was square and not round, as represented by all Bible illustrators, including Dore. The ruins cover a space of about 50,000 square feet and are about ten miles from the site of Babylon.
The ruins of the celebrated synagogue of Capernaum, believed to be the very one in which the Saviour preached, have been unearthed and many other Biblical sites around the ancient city have been identified.
Capernaum was the home of Jesus during nearly the whole of his Galilean ministry and the scene of many of his most wonderful miracles. The site of Capernaum is now known as Tell Hum. There are ruins scattered about over a radius of a mile. The excavating which revealed the ruins of the synagogue was done under supervision of a German archaeologist named Kohl. This synagogue was composed of white limestone blocks brought from a distance and in this respect different from the others which were built of the local black volcanic rock. The carvings unearthed in the ruins are very beautiful and most of them in high relief work, representing trailing vines, stately palms, clusters of dates, roses and acanthus. Various animal designs are also shown and one of the famous seven-branched candlesticks which accompanied the Ark of the Covenant.
Most of the incidents at Capernaum mentioned in the Bible were connected with the synagogue, the ruins of which have just been uncovered. The centurion who came to plead with Jesus about the servant was the man who built the synagogue (Luke VII:1-10). In the synagogue, Jesus healed the man with the unclean spirit (Mark I:21-27). In this synagogue, the man with the withered hand received health on the Sabbath Day (Matthew XII:10-13). Jairus, whose daughter was raised from the dead, was a ruler of the synagogue (Luke VIII:3) and it was in this same synagogue of Capernaum that Jesus preached the discourse on the bread of life (John VI:26-59). The hill near Capernaum where Jesus fed the multitude with five loaves and two fishes is also identified.
The stoning of St. Stephen and the conversion of St. Paul are two great events of the New Testament which lend additional interest to the explorations now being carried on at the ancient City of Damascus. Damascus lays claim to being the most ancient city in the world and its appearance sustains the claim. Unlike Jerusalem and many other ancient cities, it has never been completely destroyed by a conqueror. The Assyrian monarch, Tiglath Pileser, swept down on it, 2,700 years ago, but he did not succeed in wiping it out. Other cities came into being long after Damascus, they flourished, faded and passed away; but Damascus still remains much the same as in the early time. Among the famous places which have been identified in this ancient city is the house of Ananias the priest and the place in the wall where Paul was let down by a basket is pointed out. The scene of the conversion of St. Paul is shown and also the "Street called Straight" referred to in Acts IX:II.
Jerusalem, birthplace and cradle of Christianity, offers a vast and interesting field to the archaeologist. One of the most remarkable of recent discoveries relates to the building known as David's castle. Major Conder, a British engineer in charge of the Palestine survey, has proved that this building is actually a part of the palace of King Herod who ordered the Massacre of the Innocents in order to encompass the destruction of the Infant Saviour.
The tomb of Hiram is another relic discovered at the village of Hunaneh on the road from Safed to Tyre; it recalls the days of David. Hiram was King of Tyre in the time of David. The tomb is a limestone structure of extraordinary massiveness Unfortunately the Mosque of Omar stands on the site of Solomon's Temple and there is no hope of digging there. As for the palace of Solomon, it should be easy to find the foundations, for Jerusalem has been rebuilt several times upon the ruins of earlier periods and vast ancient remains must be still buried there. The work is being pushed vigorously at present and the future should bring to light many interesting relics. At last the real site of the Crucifixion may be found with many mementoes of the Saviour, and the Apostles.
Professor Flinders Petrie, the famous English archaeologist, has recently explored the Sinaitic peninsula and has found many relics of the Hebrews' passage through the country during the Exodus and also many of a still earlier period. He found a remarkable number of altars and tombs belonging to a very early form of religion. On the Mount where Moses received the tables of the law is a monastery erected by the Emperor Justinian 523 A.D. Although the conquering wave of Islam has swept over the peninsula, leaving it bare and desolate, this monastery still survives, the only Christian landmark, not only in Sinai but in all Arabia. The original tables of stone on which the Commandments were written, were placed in the Ark of the Covenant and taken all through the Wilderness to Palestine and finally placed in the Temple of Solomon. What became of it when the Temple was plundered and destroyed by the Babylonians is not known.
Clay tablets have been found at Nineveh of the Creation and the Flood as known to the Assyrians. These tablets formed part of a great epic poem of which Nimrod, the mighty hunter, was the hero.
Explorers are now looking for the palace of Nimrod, also that of Sennacherib, the Assyrian monarch who besieged Jerusalem. The latter despoiled the Temple of many of its treasures and it is believed that his palace, when found, may reveal the Tables of the Law, the Ark of the Covenant, the Seven-branched candlestick, and many of the golden vessels used in Israelitish worship.
Ur of the Chaldees, birthplace of Abraham, father and founder of the Hebrew race, is a rich field for the archaeologist to plough. Some tablets have already been discovered, but they are only a mere suggestion as to future possibilities. It is believed by some eminent investigators that we owe to Abraham the early part of the Book of Genesis describing the Creation, the Tower of Babel and the Flood, and the quest of archaeologists is to find, if not the original tablets, at least some valuable records which may be buried in this neighborhood.
Excavators connected with the American School at Jerusalem are busy at Samaria and they believe they have uncovered portions of the great temple of Baal, which King Ahab erected in honor of the wicked deity 890 B.C. When the remains of this temple are fully uncovered it will be learned just how far the Israelites forsook the worship of the true God for that of Baal.
The Germans have begun work on the site of Jericho, once the royal capital of Canaan, and historic chiefly from the fact that Joshua led the Israelites up to its walls, reported to be impregnable, but which "fell down at the blast of the trumpet." Great piles have been unearthed here which it is thought formed a part of the original masonry. One excavator believes he has unearthed the ruins of the house of Rahab, the woman who sheltered Joshua's spies. Another thinks he has discovered the site of the translation of Elijah, the Prophet, from whence he was carried up to heaven in a fiery chariot.
Every Christian will be interested in learning what is to be found in Nazareth where Jesus spent his boyhood. Archaeologists have located the "Fount of the Virgin," and the rock from which the infuriated inhabitants attempted to hurl Christ.
In the "Land of Goshen" where the Israelites in a state of servitude worked for the oppressing Pharaoh (Rameses II), excavators have found bricks made without straw as mentioned in Scripture, undoubtedly the work of Hebrew slaves, also glazed bead necklaces. They are looking for the House of Amran, the father of Moses, where the great leader was born.
The site of Arbela, where Alexander the Great won his mightiest victory over Darius, has been discovered. It is a series of mounds on the Western bank of the Tigris river between Nineveh and Bagdad. All the treasures of Darius were taken and Alexander erected a great palace. Bronze swords, cups and pieces of sculpture have been unearthed and it is supposed there are vast stores of other remains awaiting the tool and patience of the excavator. The famous Sultan Saladin took up his residence here in 1184 and doubtless many relics of his royal time will be discovered.
The remains of the city of Pumbaditha have been identified with the immense mound of Abnar some twenty miles from Babylon, on the banks of the Euphrates. This was the centre of Jewish scholarship during the Babylonian exile. One of the great schools in which the Talmud was composed was located here. The great psalm, "By the waters of Babylon, we sat down and wept." was also composed on this spot, and here, too, Jeremiah and Isaiah thundered their impassioned eloquence. Broken tombs and a few inscribed bowls have been brought to light. Probably the original scrolls of the Talmud will be found here. Several curiously wrought vases and ruins have been also unearthed.
Several monuments bearing inscriptions which are sorely puzzling the archaeologists have recently been unearthed at the site of Boghaz-Keni which was the ancient, if not original capital, of the mysterious people called the Hittites who have been for so long a worry to Bible students. Archaeology has now revealed the secret of this people. There is no doubt they were of Mongolian origin, as the monuments just discovered represent them with slant eyes and pigtails. No one as yet has been able to read the inscriptions. They were great warriors, great builders and influenced the fate of many of the ancient nations.
In many other places throughout these lands, deep students of Biblical lore are pushing on the work of excavation and daily adding to our knowledge concerning the peoples and nations in whom posterity must ever take a vital interest.
A short time ago, Professor Doerpfeld announced to the world that he had discovered on the island of Ithaca, off the west coast of Greece, the ruins of the palace of Ulysses, Homer's half-mythical hero of theOdyssey. The German archaeologist has traced the different rooms of the palace and is convinced that here is the very place to which the hero returned after his wanderings. Near it several graves were found from which were exhumed silver amulets, curiously wrought necklaces, bronze swords and metal ornaments bearing date 2,000 B.C., which is the date at which investigators lay the Siege of Troy.
If the ruins be really those of the palace of Ulysses, some interesting things may be found to throw a light on the Homeric epic. As the schoolboys know, when Ulysses set sail from Troy for home, adverse winds wafted him to the coast of Africa and he beat around in the adjacent seas and visited islands and spent a considerable time meeting many kinds of curious and weird adventures, dallying at one time with the lotus-eaters, at another braving the Cyclops, the one-eyed monsters, until he arrived at Ithaca where "he bent his bow and slew the suitors of Penelope, his harassed wife."
In North America are mounds, earthworks, burial sites, shell heaps, buildings of stone and adobe, pictographs sculptured in rocks, stone implements, objects made of bone, pottery and other remains which arouse the enthusiasm of the archaeologist. As the dead were usually buried in America, investigators try to locate the ancient cemeteries because, besides skeletons, they usually contain implements, pottery and ornaments which were buried with the corpses. The most characteristic implement of early man in America was the grooved axe, which is not found in any other country. Stone implements are plentiful everywhere. Knives, arrow-points and perforators of chipped stone are found in all parts of the continent. Beads and shells and pottery are also found in almost every State.
The antiquity of man in Europe has been determined in a large measure by archaeological remains found in caves occupied by him in different ages, but the exploration of caves in North America has so far failed to reveal traces of different degrees of civilization.
Primitive Tunneling—Hoosac Tunnel—Croton Aqueduct—Great AlpineTunnels—New York Subway—McAdoo Tunnels—How Tunnels are Built.
The art of tunnel construction ranks among the very oldest in the world, if not the oldest, for almost from the beginning of his advent on the earth man has been tunneling and boring and making holes in the ground. Even in pre-historic time, the ages of which we have neither record nor tradition, primitive man scooped out for himself hollows in the sides of hills, and mountains, as is evidenced by geological formations and by the fossils that have been unearthed. The forming of these hollows and holes was no indication of a superior intelligence but merely manifested the instincts of nature in seeking protection from the fury of the elements and safety from hostile forces such as the onslaughts of the wild and terrible beasts that then existed on the earth.
The Cave Dwellers were real tunnelers, inasmuch as in construction of their rude dwellings they divided them into several compartments and in most cases chose the base of hills for their operations, boring right through from side to side as recent discoveries have verified.
The ancient Egyptians built extensive tunnels for the tombs of their dead as well as for the temples of the living. When a king of Thebes ascended the throne he immediately gave orders for his tomb to be cut out of the solid rock. A separate passage or gallery led to the tomb along which he was to be borne in death to the final resting place. Some of the tunnels leading to the mausoleums of the ancient Egyptian kings were upwards of a thousand feet in length, hewn out of the hard solid rock. A similar custom prevailed in Assyria, Mesopotamia, Persia and India.
The early Assyrians built a tunnel under the Euphrates river which was 12 feet wide by 15 high. The course of the river was diverted until the tunnel was built, then the waters were turned into their former channel, therefore it was not really a subaqueous tunnel.
The sinking of tunnels under water was to be one of the triumphs of modern science.
Unquestionably the Romans were the greatest engineers of ancient times. Much of their masonry work has withstood the disintegrating hand of time and is as solid and strong to-day as when first erected.
The "Fire-setting" method of tunneling was originated by them, and they also developed the familiar principle of prosecuting the work at several points at the same time by means of vertical shafts. They heated the rock to be excavated by great fires built against the face of it. When a very high temperature was reached they turned streams of cold water on the heated stone with the result that great portions were disintegrated and fell off under the action of the water. The Romans being good chemists knew the effect of vinegar on lime, therefore when they encountered calcareous rock instead of water they used vinegar which very readily split up and disintegrated this kind of obstruction. The work of tunneling was very severe on the laborers, but the Romans did not care, for nearly all the workmen were slaves and regarded in no better light than so many cattle. One of the most notable tunnels constructed by the old Romans was that between Naples and Pozzuoli through the Posilipo Hills. It was excavated through volcanic tufa and was 3,000 feet long, 25 feet wide, and of the pointed arch style. The longest of the Roman tunnels, 3-1/2 miles, was built to drain Lake Fucino. It was driven through calcareous rock and is said to have cost the labor of 30,000 men for 11 years.
Only hand labor was employed by the ancient people in their tunnel work. In soft ground the tools used were picks, shovels and scoops, but for rock work they had a greater variety. The ancient Egyptians besides the hammer, chisel and wedges had tube drills and saws provided with cutting edges of corundum or other hard gritty material.
For centuries there was no progress in the art of tunneling. On the contrary there was a decline from the earlier construction until late in the 17th century when gunpowder came into use as an explosive in blasting rock. The first application of gunpowder was probably at Malpas, France, 1679-1681, in the construction of the tunnel on the line of the Languedoc Canal 510 feet long, 22 feet wide and 29 feet high.
It was not until the beginning of the nineteenth century that the art of tunnel construction, through sand, wet ground or under rivers was undertaken so as to come rightly under the head of practical engineering. In 1803 a tunnel was built through very soft soil for the San Quentin Canal in France. Timbering or strutting was employed to support the walls and roof of the excavation as fast as the earth was removed and the masonry lining was built closely following it. From the experience gained in this tunnel were developed the various systems of soft ground subterranean tunneling in practice at the present day.
The first tunnel of any extent built in the United States was that known as the Auburn Tunnel near Auburn, Pa., for the water transportation of coal. It was several hundred feet long, 22 feet wide and 15 feet high. The first railroad tunnel in America was also in Pennsylvania on the Allegheny-Portage Railroad, built in 1818-1821. It was 901 feet long, 25 feet wide and 21 feet high.
What may be called the epoch making tunnel, the construction of which first introduced high explosives and power drills in this country, was the Hoosac in Massachusetts commenced in 1854 and after many interruptions brought to completion in 1876. It is a double-track tunnel nearly 5 miles in length. It was quickly followed by the commencement of the Erie tunnel through Bergen Hill near Hoboken, N.J. This tunnel was commenced in 1855 and finished in 1861. It is 4,400 feet long, 28 feet wide and 21 feet high. Other remarkable engineering feats of this kind in America are the Croton Aqueduct Tunnel, the Hudson River Tunnel, and the New York Subway.
The great rock tunnels of Europe are the four Alpine cuts known as Mont Cenis, St. Gothard, the Arlberg and the Simplon. The Mont Cenis is probably the most famous because at the time of its construction it was regarded as the greatest engineering achievement of the modern world, yet it is only a simple tunnel 8 miles long, while the Simplon is a double tunnel, each bore of which is 12-1/4 miles. The chief engineer of the Mont Cenis tunnel was M. Sommeiler, the man who devised the first power drill ever used in such work. In addition to the power drill the building of this tunnel induced the invention of apparatus to suck up foul air, the air compressor, the turbine and several other contrivances and appliances in use at the present time.
Great strides in modern tunneling developed the "shield" and brought metal lining into service. The shield was invented and first used by Sir M. I. Brunel, a London engineer, in excavating the tunnel under the River Thames, begun in 1825 and finished in 1841. In 1869 another English engineer, Peter Barlow, used an iron lining in connection with a shield in driving the second tunnel under the Thames at London. From a use of the shield and metal lining has grown the present system of tunneling which is now universally known as the shield system.
Great advancement has been made in the past few years in the nature and composition of explosives as well as in the form of motive power employed in blasting. Powerful chemical compositions, such as nitroglycerine and its compounds, such as dynamite, etc., have supplanted gunpowder, and electricity, is now almost invariably the firing agent. It also serves many other purposes in the work, illumination, supplying power for hoisting and excavating machinery, driving rock drills, and operating ventilating fans, etc. In this field, in fact, as everywhere else in the mechanical arts, the electric current is playing a leading part.
To the English engineer, Peter Barlow, above mentioned, must be given the credit of bringing into use the first really serviceable circular shield for soft ground tunneling. In 1863 he took out a patent for such a shield with a cylindrical cast iron lining for the completed tunnel. Of course James Henry Greathead very materially improved the shield, so much so indeed that the present system of tunneling by means of circular shields is called the Greathead not the Barlow system. Greathead and Barlow entered into a partnership in 1869. They constructed the tunnel under the Tower of London 1,350 feet in length and seven feet in diameter which penetrated compact clay and was completed within a period of eleven months. This was a remarkable record in tunnel building for the time and won for these eminent engineers a world wide fame. From thenceforth their system came into vogue in all soft soil and subaqueous tunneling. Except for the development in steel apparatus and the introduction of electricity as a motive agent, there has not been such a great improvement on the Greathead shield as one would naturally expect in thirty years.
The method of excavating a tunnel depends altogether on the nature of the obstruction to be removed for the passage. In the case of solid rock the work is slow but simple; dry, hard, firm earth is much the same as rock. The difficulties of tunneling lie in the soft ground, subaqueous mud, silt, quicksand, or any treacherous soil of a shifting, unsteady composition.
When the rock is to be removed it is customary to begin the work in sections of which there may be seven or eight. First one section is excavated, then another and so on to completion. The order of the sections depends upon the kind of rock and upon the time allotted for the job and several other circumstances known to the engineer. If the first section attacked be at the top immediately beneath the arch of the proposed tunnel, next to the overlying matter, it is called a heading, but if the first cutting takes place at the bottom of the rock to form the base of the tunnel it is called a drift.
Driving a heading is the most difficult operation of rock tunneling. Sometimes a heading is driven a couple of thousand feet ahead of the other sections. In soft rock it is often necessary to use timber props as the work proceeds and follow up the excavating by lining roof and sides with brick, stone or concrete.
The rock is dislodged by blasting, the holes being drilled with compressed air, water force or electricity, and, as has been said, powerful explosives are used, nitroglycerine or some nitro-compound being the most common. Many charges can be electrically fired at the same time. If the tunnel is to be long, shafts are sunk at intervals in order to attack the work at several places at once. Sometimes these shafts are lined and left open when the tunnel is completed for purposes of ventilation.
In soft ground and subaqueous soil the "shield" is the chief apparatus used in tunneling. The most up-to-date appliance of this kind was that used in constructing the tunnels connecting New York City with New Jersey under the Hudson River. It consisted of a cylindrical shell of steel of the diameter of the excavation to be made. This was provided with a cutting edge of cast steel made up of assembled segments. Within the shell was arranged a vertical bulkhead provided with a number of doors to permit the passage of workmen, tools and explosives. The shell extended to the rear of the bulkhead forming what was known as the "tail." The lining was erected within this tail and consisted of steel plates lined with masonry. The whole arrangement was in effect a gigantic circular biscuit cutter which was forced through the earth.
The tail thus continually enveloped the last constructed portion of this permanent lining. The actual excavation took place in advance of the cutting edge. The method of accomplishing this, varied with conditions. At times the material would be rock for a few feet from the bottom, overlaid with soft earth. In such case the latter would be first excavated and then the roof would be supported by temporary timbers, after which the rock portion would be attacked. When the workmen had excavated the material in front of the shield it was passed through the heavy steel plate diaphragm in center of the shell out to the rear and the shield was then moved forward so as to bring its front again up to the face of the excavation. As the shell was very unwieldy, weighing about eighty tons, and, moreover, as the friction or pressure of the surrounding material on its side had to be overcome it was a very difficult matter to move it forward and a great force had to be expended to do so. This force was exerted by means of hydraulic jacks so devised and placed around the circumference of the diaphragm as to push against the completed steel plate lining of the tunnel. There were sixteen of these jacks employed with cylinders eight inches in diameter and they exerted a pressure of from one thousand to four thousand pounds per square inch. By such means the shield was pushed ahead as soon as room was made in front for another move.
The purpose of the shield is to prevent the inrush of water and soft material while excavating is going on; the diaphragm of the shields acts as a bulkhead and the openings in it are so devised as to be quickly closed if necessary. The extension of the shield in front of the diaphragm is designed to prevent the falling or flowing in of the exposed face of the new excavation.
The extension of the shell back from the diaphragm is for the purpose of affording opportunity to put in place the finished tunnel lining whatever it may be, masonry, cast-iron, cast-iron and masonry, or steel plates and masonry. Where the material is saturated with water as is the case in all subaqueous tunneling it is necessary to use compressed air in connection with the shield. The intensity of air pressure is determined by the depth of the tunnel below the surface of the water above it. The tunnelers work in what are called caissons to which they have access through an air lock. In many cases quick transition from the compressed air in the caisson to the open air at the surface results fatally to the workers. The caisson disease is popularly called "the bends" a kind of paralysis which is more or less baffling to medical science. Some men are able to bear a greater pressure than others. It depends on the natural stamina of the worker and his state of health. The further down the greater the pressure. The normal atmospheric pressure at the surface is about fourteen pounds to the square inch. Men in normal health should be able to stand a pressure of seventy-six pounds to the square inch and this would call for a depth of 178 feet under water surface, which far exceeds any depth worked under compressed air. For a long time one hundred feet were regarded as a maximum depth and at that depth men were not permitted to work more than an hour in one shift. The ordinary subaqueous tunnel pressure is about forty-five pounds and this corresponds to a head of 104 feet. In working in the Hudson Tunnels the pressure was scarcely ever above thirty-three pounds, yet many suffered from the "bends."
What is called a freezing method is now proposed to overcome the water in soft earth tunneling. Its chief feature is the excavating first of a small central tunnel to be used as a refrigerating chamber or ice box in freezing the surrounding material solid so that it can be dug out or blasted out in chunks the same as rock. It is very doubtful however, if such a plan is feasible.
The greatest partly subaqueous tunnels in the world are now to be found in the vicinity of New York. The first to be opened to the public is known as the Subway and extends from the northern limits of the City in Westchester County to Brooklyn. The oldest, however, of the New York tunnels counting from its origin is the "McAdoo" tunnel from Christopher Street, in Manhattan Borough, under the Hudson to Hoboken. This was begun in 1880 and continued at intervals as funds could be obtained until 1890, when the work was abandoned after about two thousand feet had been constructed. For a number of years the tunnel remained full of water until it was finally acquired by the Hudson Companies who completed and opened it to the public in 1908. Another tunnel to the foot of Cortlandt Street was constructed by the same concern and opened in 1909. Both tunnels consist of parallel but separate tubes. The railway tunnels to carry the Pennsylvania R. R. under the Hudson into New York and thence under the East River to Long Island have been finished and are great triumphs of engineering skill besides making New York the most perfectly equipped city in the world as far as transit is concerned.
The greatest proposed subaqueous tunnel is that intended to connect England with France under the English Channel a distance of twenty-one miles. Time and again the British Parliament has rejected proposals through fear that such a tunnel would afford a ready means of invasion from a foreign enemy. However, it is almost sure to be built. Another projected British tunnel is one which will link Ireland and Scotland under the Irish Sea. If this is carried out then indeed the Emerald Isle will be one with Britain in spite of her unwillingness for such a close association.
England already possesses a famous subaqueous tunnel in that known as the Severn tunnel under the river of that name. It is four and a half miles long, although it was built largely through rock. Water gave much trouble in its construction which occupied thirteen years from 1873 to 1886. Pumps were employed to raise the water through a side heading connecting with a shaft twenty-nine feet in diameter. The greatest amount of water raised concurrently was twenty-seven million gallons in twenty-four hours but the pumps had a capacity of sixty-six million gallons for the same time.
The greatest tunnel in Europe is the Simplon which connects Switzerland with Italy under the Simplon Pass in the Alps. It has two bores twelve and one-fourth miles each and at places it is one and one-half miles below the surface. The St. Gothard also connecting Switzerland and Italy under the lofty peak of the Col de St. Gothard is nine and one-fourth miles in length. The third great Alpine tunnel, the Arlberg, which is six and one-half miles long, forms a part of the Austrian railway between Innsbruck and Bluedenz in the Tyrol and connects westward with the Swiss railroads and southward with those of Italy.
Two great tunnels at the present time are being constructed in the United States, one of these which is piercing the backbone of the Rockies is on the Atlantic and Pacific railway. It begins near Georgetown, will pass under Gray's peak and come out near Decatur, Colorado, in all a length of twelve miles. The other American undertaking is a tunnel under the famous Pike's Peak in Colorado which when completed will be twenty miles long.
It can clearly be seen that in the way of tunnel engineering Uncle Sam is not a whit behind his European competitors.
Electrically Equipped Houses—Cooking by Electricity—Comforts andConveniences.
Science has now pressed the invisible wizard of electricity into doing almost every household duty from cleaning the windows to cooking the dinner. There are many houses now so thoroughly equipped with electricity from top to bottom that one servant is able to do what formerly required the service of several, and in some houses servants seem to be needed hardly at all, the mistresses doing their own cooking, ironing, and washing by means of electricity.
In respect to taking advantage of electricity to perform the duties of the household our friends in Europe were ahead of us, though America is pre-eminently the land of electricity—the natal home of the science. We are waking up, however, to the domestic utility of this agent and throughout the country at present there are numbers of homes in which electricity is employed to perform almost every task automatically from feeding the baby to the crimping of my lady's hair in her scented boudoir.
There is now no longer any use for chimneys on electrically equipped houses, for the fires have been eliminated and all heat and light drawn from the electric street mains. A description of one of these houses is most interesting as showing what really can be accomplished by this wonderful source of power.
Before the visitor to such a house reaches the gate or front door his approach is made known by an annunciator in the hall, which is connected with a hidden plate in the entrance path, which when pressed by the feet of the visitor charges the wire of the annunciator. A voice comes through the horn of a phonograph asking him what he wishes and telling him to reply through the telephone which hangs at the side of the door. When he has made his wants known, if he is welcome or desired, there is a click and the door opens. As he enters an electrically operated door mat cleans his shoes and if he is aware of the equipments of the house, he can have his clothes brushed by an automatic brush attached to the hat-rack in the hall. An escalator or endless stairway brings him to the first floor where he is met by the host who conducts him to the den sacred to himself. If he wishes a preprandial cigar, the host touches a segment of the wall, apparently no different in appearance from the surrounding surface, and a complete cigar outfit shoots out to within reach of the guest. When the gong announces dinner he is conducted to the dining hall where probably the uses to which electricity can be put are better exemplified than in any other part of the house. Between this room and the kitchen there is a perfect electric understanding. The apartments are so arranged that electric dumbwaiter service is operated between the centre of the dining table itself and the serving table in the kitchen. The latter is equipped with an electric range provided with electrically heated ovens, broilers, vegetable cookers, saucepans, dishes, etc., sufficient for the preparation of the most elaborate house banquet. The chef or cook in charge of the kitchen prepares each dish in its proper oven and has it ready waiting on the electric elevator at the appointed time when the host and his guest or guests, or family, as the case may be, are seated at the dining table. The host or whoever presides at the head of the table merely touches a button concealed on the side of the mahogany and the elevator instantly appears through a trap-door in the table, which is ordinarily closed by two silver covers which look like a tray. In this way the dish seemingly miraculously appears right on top of the table. When each guest is served it returns to the kitchen by the way it came and a second course is brought on the table in a similar manner and so on until the dinner is fully served. Fruits and flowers tastefully arranged adorn the centre of the dining table and minute electric incandescent lamps of various colors are concealed in the roses and petals and these give a very pretty effect, especially at night.
Beneath the table nothing is to be seen but two nickel-plated bars which serve to guide the elevators.
Down in the kitchen the cooking is carried on almost mechanically by means of an electric clock controlling the heating circuits to the various utensils. The cook, knowing just how long each dish will require to be cooked, turns on the current at the proper time and then sets the clock to automatically disconnect that utensil when sufficient time, so many minutes to the pound, has elapsed. When this occurs a little electric bell rings, calling attention to the fact, that the heat has been shut off.
Another kitchen accessory is a rotating table on which are mounted various household machines such as meat choppers, cream whippers, egg beaters and other apparatus all electrically operated.
There is also an electric dishwasher and dryer and plate rack manipulator which places the dishes in position when clean and dried.
The advantages of cooking by electricity are apparent to all who have tested them. Food cooked in an electric baking oven is much superior than when cooked by any other method because of the better heat regulation and the utter cleanliness, there being absolutely no dust whatever as in the case when coal is used. The electric oven does not increase the temperature nor does it exhaust the pure air in the room by burning up the oxygen. The time required for cooking is about the same as with coal.
The perfect cleanliness of an electric plate warmer is sufficient to warrant its use. It keeps dishes at a uniform temperature and the food does not get scorched and become tough.
Steaks prepared on electric gridirons and broilers are really delicious as they are evenly done throughout and retain all the natural juices of the meat; there is no odor of gas or of the fire and portions done to a crisp while others are raw on the inside. In toasting there is no danger of the bread burning on one side more than on the other, or of its burning on either side and a couple of dozen slices can be done together on an ordinary instrument at the same time. The electric diskstove, flat on the top, like a ball cut in two, can be also utilized as a toaster or for heating any kettles or pots or vessels with flat bottoms.
Very appetizing waffles are made with electric waffle irons, because the bottom and top irons are uniformly heated, so that the irons cook the waffles from both sides at the same time.
Electric potato peeling machines consist of a stationary cylinder opened at the top for the reception of the potatoes and having a revolving disk at the bottom. The cylinder has a rough surface or is coated with diamond flint, so that when the disk revolves the potatoes are thrown against the sides of the cylinder and the skin is scraped off. There is no deep cutting as when peeled by a knife, therefore, much waste is avoided. While the potatoes are being scraped, a stream of water plays upon them taking away the skins and thoroughly cleansing the tubers.
Among other electric labor savers connected with the culinary department may be mentioned floor-scrubbers, dish-washers, coffee-grinders, meat choppers, dough-mixers and cutlery-polishers, all of which give complete satisfaction at a paltry cost and save much time and labor. A small motor can drive any of these instruments or several can be attached and run by the same motor. The operation of an ordinary snap switch will supply energy to electric water-heaters attached to the kitchen boiler or to the faucet. The instantaneous water heater also purifies the water by killing the bacteria contained in it.
The electric tea kettle makes a brew to charm the heart of a connossieur. In fact all cooking done by electricity whether it is the frying of an egg or the roasting of a steak is superior in every way to the old methods and what accentuates its use is the cleanliness with which it can be performed. And it should be taken into consideration that in electric cooking there is no bending over hot stoves and ranges or a stuffy evil smelling smoky atmosphere, but on the contrary, fresh air, cleanliness and coolness which make cooking not the drudgery it has ever been, but a real pleasure.
Let us take a glance at the laundry in the electrically equipped house. There is a large tub with a wringer attached to it and a simple mechanism by which a small motor can either be connected with the tub or the wringer as required. The washing is performed entirely by the motor and in a way prevents the wear and tear associated with the old method of scrubbing and rubbing done at the expense of much "elbow grease." The motor turns the tub back and forth and in this way the soapy water penetrates the clothes, thus removing the dirt without injuring or tearing the fabric. In the old way, the clothes were moved up and down in the water and torn and worn in the process. By the new way it is the water which moves while the clothes remain stationary. When the clothes are thoroughly washed, the motor is attached to the wringer and they are passed through it; they are completely dried by a specially constructed electric fan. Whatever garments are to be ironed are separated and fed to a steel roll mangle operated by a motor which gives them a beautiful finish. The electric flat iron plays also an important part in the laundry as it is clean and never gets too hot nor too cold and there is no rushing back to replenish the heaters. One is not obliged to remain in the room with a hot stove, and suffer the inconveniences. No heat is felt at all from the iron as it is all concentrated on the bottom surface. It is a regular blessing to the laundress especially in hot weather. There is a growing demand in all parts of the country for these electric flat-irons.
Electricity plays an important role in the parlor and drawing-room. The electric fireplace throws out a ruddy glow, a perfect imitation of the wide-open old-fashioned fireplaces of the days of our grandmothers. There are small grooves at certain sections in the flooring over which chairs and couches can be brought to a desired position. When the master drops into his favorite chair by the fireplace if he wishes a tune to soothe his jangled nerves, there is an electric attachment to the piano and he can adjust it to get the air of his choice without having to ask any one to play for him. In the drawing-room an electric fountain may be playing, its jets reflecting the prismatic colors of the rainbow as the waters fall in iridescent sparkle among the lights. Such a fountain is composed of a small electric motor and a centrifugal pump, the latter being placed in the interior of a basin and connected directly to the motor shaft. The pump receives the water from the basin and conveys it through pipes and a number of small nozzles thus producing cascades. The water falling upon an art glass dome, beneath which are small incandescent lamps, returns to the basin and thence again to the pump. There is no necessity of filling the fountain until the water gets low through evaporation. When the lights are not in colored glass, the water may be colored and this gives the same effect. To produce the play of the fountain and its effects, it is only necessary to connect it to any circuit and turn on the switch. The dome revolves by means of a jet of water driven against flanges on the under side of the rim of the dome and in this way beautiful and prismatic effects are produced. The motor is noiseless in operation. In addition to the pretty effect the fountain serves to cool and moisten the air of the room.
The sleeping chambers are thoroughly equipped. Not only the rooms may be heated by electricity but the beds themselves. An electric pad consisting of a flexible resistance covered with soft felt is connected by a conductor cord to a plug and is used for heating beds or if the occupant is suffering from rheumatism or indigestion or any intestinal pain this pad can be used in the place of the hot water bottle and gives greater satisfaction. There is a heat controlling device and the circuit can be turned on or off at will.
There are many more curious devices in the electrically equipped house which could they have been exhibited a generation or so ago, would have condemned the owner as a sorcerer and necromancer of the dark ages, but which now only place him in the category of the smart ones who are up to date and take advantage of the science and progress of the time.
Electric Energy—High Pressure—Transformers—Development ofWater-power.
The electrical transmission of power is exemplified in everything which is based on the generation of electricity. The ordinary electric light is power coming from a generator in the building or a public street-dynamo.
However, when we talk in general terms of electric transmission we mean the transmission of energy on a large scale by means of overhead or underground conductors to a considerable distance and the transformation of this energy into light and heat and chemical or mechanical power to carry on the processes of work and industry. When the power or energy is conveyed a long distance from the generator, say over 30 miles or more, we usually speak of the system of supply as long distance transmission of electric energy. In many cases power is conveyed over distances of 200 miles and more. When water power is available as at Niagara, the distance to which electric energy can be transmitted is considerably increased.
The distance to a great extent depends on the cost of coal required for generation at the distributing point and on the amount of energy demanded at the receiving point. Of course the farther the distance the higher must be the voltage pressure.
Electrical engineers say that under proper conditions electric energy may be transmitted in large quantity to a distance of 500 miles and more at a pressure of about 170,000 volts. If such right conditions be established then New York, Chicago and several other of our large cities can get their power from Niagara.
In our cities and towns where the current has only to go a short distance from the power house, the conductors are generally placed in cables underground and the maximum electro-motive force scarcely ever exceeds 11,000 volts. This pressure is generated by a steam-driven alternating-current generator and is transmitted over the conductors to sub-stations, where by means of step-down transformers, the pressure is dropped to, say, 600 volts alternating current which by rotary converters is turned into direct current for the street mains, for feeders of railways and for charging storage batteries which in turn give out direct current at times of heavy demand.
That electric transmission of energy to long distances may be successfully carried out transformers are necessary for raising the pressure on the transmission line and for reducing it at the points of distribution. The transformer consists of a magnetic circuit of laminated iron or mild steel interlinked with two electric circuits, one, the primary, receiving electrical energy and the other the secondary, delivering it to the consumer. The effect of the iron is to make as many as possible of the lines of force set up by the primary current, cut the secondary winding and there set up an electromotive force of the same frequency but different voltage.
The transformer has made long distance the actual achievement that it is. It is this apparatus that brought the mountain to Mohammed. Without it high pressure would be impossible and it is on high pressure that success of long distance transmission depends.
To convey electricity to distant centres at a low pressure would require thousands of dollars in copper cables alone as conductors. To illustrate the service of the transformer in electricity it is only necessary to consider water power at a low pressure. In such a case the water can only be transmitted at slow speed and through great openings, like dams or large canals, and withal the force is weak and of little practical efficiency, whereas under high pressure a small quantity can be forced through a small pipe and create an energy beyond comparison to that developed when under low pressure.
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 space 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 principally 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 canal 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 canal in this case ends on high ground 130 feet from the power house and the water passes 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 canals 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 canals, 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 illustration of this class 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 canal 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 Francisco by 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 Francisco Bay. 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.
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 shell 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 shell 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 shell 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 space 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 shell 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 space 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 shells, 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 shell 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 surpassed 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 classes, viz., the main and the second batteries. The main battery comprises the heaviest guns on the ship, those firing large shell 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 shell 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 classes previously constructed. Both England and the United States have constructed enormous war vessels within the past decade. The BritishDreadnoughtbuilt 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 theDreadnoughttype have a normal draft of twenty-seven feet and a naval displacement of eighteen thousand and six hundred tons. Armored cruisers of the BritishInvincibleclass 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 surpass the best of those of any other navy in the world. TheDelawareandNorth Dakotaeach 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. TheDelaware, which has reciprocating engines, exceeded her contract speed of twenty-one knots on her runs over a measured mile course in Penobscot 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.
TheNorth Dakotais furnished with Curtis turbine engines. Here is a comparison of the two ships:
NorthDelaware DakotaFastest run over measured mile……… 21.98 22.25Average of five high runs………….. 21.44 21.83Full power trial speed…………….. 21.56 21.64Full power trial horsepower………… 28,600. 31,400.Full power trial, coalconsumption, tons per day………… 578. 583.Nineteen-knot trialcoal consumption, tons per day……. 315. 295.Twelve-knot trial coalconsumption, tons per day………….111. 105.
TheFlorida, a 21,825 ton boat, was launched from the Brooklyn NavyYard last May 12. Her sister ship, theUtah, took water the previousDecember at Camden.
Here is a comparison of theNorth Dakotaof 1908 and theFloridaof 1910:
N. Dakota FloridaLength 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 tonsCoal Supply 2,500 tons 2,500 tonsOil 400 tons 400 tonsBelt Armor 12 in. to 8 in. 12 in. to 8 in.Turret Armor 12 inches 12 inchesBattery armor 6 in. 6-1/2 in.Smoke stack protection 6 inches 9-1/2 inchesl2-inch guns Ten Ten5-inch guns Fourteen SixteenSpeed 21 knots 20.75 knots
TheFloridahas 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 theArkansasandWyoming.
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.