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Atlantic westward to the calmer waters of the Pacific, and over all this vast continent one people, one law, one language, and one faith; and in the full fruition of our arms and arts, our industry and dominion, this whole land begemmed with mighty cities of civilization; then, with eyes lifted toward heaven, behold upon the starry scroll of the future Columbia's name recorded, her future honors and happiness inscribed. Then, closing the vision, let us turn to man, and with a voice that will reach all hearts and consciences, hid him go forth in peace to the great mission of the higher and better conquest of the world; and
"Thou, too, sail on, O Ship of State;
Our hearts, our hopes, are all with thee;
Our faith triumphant o'er our fears,
Are all with thee are all with thee!"
"Melodia rules thy destiny, O Land
Of coming years; O Empire wise and grand,
The consecrated home of Poetry
The fairer Greece, adorned with noblest art,
The four great Angels of the coming time,
To ancient thought, beyond the waves away;
THE GREAT BRIDGE NOW BEING BUILT OVER THE MISSISSIPPI, AT ST. LOUIS.
"What a glorious future may we not anticipate for our own St. Louis! Why, sir, I imagine I can see the Oriental traveler, on his brief excursion round the world, pause upon the central span of the Eads Bridge, and, amid a prodigality of gigantic achievements of science and progressive effort, still read in the distant future developments of equal or greater magnitude. He stands. upon a structure which rests upon the deep foundations of the earth itself, and presents in its strength and massive grandeur, in its piers of granite and arches of steel, fit emblems of our moral as well as physicals tructures, the steadfastness and wisdom of our institutions, and the solidity of our industries. Beneath him flows the great Father of Waters, bearing on its bosom the argosies of an empire, while on every hand the evidences of triumphant art command his attention. A city of 1,000,000 inhabitants lies before him, and it may be on one of its ascending steppes the capital of the nation rears its peerless dome. Strange wonders, these, of Time's begetting, and of progressive revolutions! The providential mystery which hid this continent from the knowledge of the civilized world for thousands of years, begins to clear away under the sunshine of fact which surrounds him, and the grand revelation is made that it was reserved for a period when mankind should aim to be fraternal, and the victories of peace should be acknowledged the erowning glories of ambition."-B. R. BONNER.
Each age and each nation produces its great works in some phase of human progress. The early Jews built the tower of Babel; Egypt had the pyramids. and Catacombs; Greece her Parthenon and unequaled temples of worship; Rome had her Coliseum; the middle ages their walled cities. But modern civilization, passing beyond the age of selfishness, ambition, and idolatry, gives to mankind magnificent structures of greater use as the triumphs of the genius of the race.
The greatest work of mechanical art that the world has yet beheld is the Crystal Palace of the nineteenth century. It combines in one grand masterpiece of art, and one glow of associated beauty, the highest civilization and progress
The leading feature of the present age is the strife for commercial dominion. In this department of civilization is enlisted more capital, talent, and men than in any other. All the rapid strides of the race are made in its interestwhether in the achievement of art, of science, or of genius. The wild billows of the Atlantic have been defied by steam and electricity, and the two great continents of kindred shores united by these subtle agents; and now with one steady grand march does civilization, carried by the tides of men, continue its journey to the West-to the high mountains, and the broad and calmer waters of the wide Pacific Ocean. With these great movements come the masterworks of mechanics and arts.
Since the invention of the steam engine, the railway system may be regarded as the greatest aid to civilization the arts have produced, on account of the rapid
intercommunion of men and ideas, and the exchange of products. But a great and valuable railway system without bridges to cross the inland streams would be an impossibility; hence the remarkable development of genius and art, and the concentration of capital, to construct in ample proportions these masterfabrics for commercial use. Nor are they constructed as the easy work common to the ordinary routine of life. But rather are they, who project great works in advance of the resistless moving times, compelled to contend against a vast array of ignorance, prejudice, and selfishness. Yes, there is one thing. common in the history of all great undertakings that have to break a new path: they have to combat against frivolous objections and contempt, and, even in the best cases, against the unsympathetic attitude of the masses. the same time it must be confessed that these opposing elements have never failed to pass into their opposites, as soon as perseverance, talent, and business energy on the part of individuals have, in spite of them, realized what has once been acknowledged as possible and necessary. In all such cases contempt has been exchanged for admiration, doubt has been compelled to give way; and the more rapidly and victoriously the enterprise, which was once so strongly doubted or even assailed, progresses, the more surprisingly does the number of those increase who would fain have it believed that they stood as prophets of good by its cradle. Such was the case-to confine our examples to American soil-with the Erie canal, with the leveling of Chicago, with the Pacific railroads, and finally with that immense structure which, before the face of St. Louis, is soon destined to span the Father of Waters. This one circumstance might be sufficient to secure the work its proper place among the great feats of humanity in modern times. But such is no longer necessary as an argument; the structure has its days of combat behind it—already its creators can point with silent finger to the actual progress which it has made, and to the point which it has at this moment attained, and allow that which has already been accomplished to speak for that which is yet to be accomplished. And it speaks irresistibly; it tells us not only that the completion of a work which in its line has no peer, is certain, but it tells us also that, as in the case of the Pacific railways, the goal will be reached many a day sooner than the original calculations and pre-suppositions led us to expect.
That the trade of the central portion of the Mississippi Valley, which centers in St. Louis, and advances every year with such gigantic strides, was not sufficiently provided for by the present arrangements for transportation across the broad stream which separates Missouri and Illinois, or, to speak more correctly, the true East and West of the United States, has been known and seen by every one for many years.
Passing from this general allusion to the struggle which enterprise is compelled to wage against established conditions, we at once submit a general statement of the great Bridge under consideration.
The plan of the Bridge, as it is now being built, is quite original in many particulars, and when completed will, in all probability, be superior to any structure of the kind in the world. So great and important is the structure, that a complete description of its main work will not be uninteresting to the
general reader; for the work itself has its lesson as well as its value, and therefore its manner of building, as well as its style of structure, will be of great public interest.
THE PIERS OF THE BRIDGE.
The locality at the river chosen for the bridge is a scene of the strangest and most exciting kind. Along the banks are extensive workshops, heaps of hewn stone, beams, iron-work and cement barrels, forges, offices and sheds for supplies, derricks and other arrangements for hoisting, and pile-drivers, whose construction alone is a sort of miracle, and finally the lofty bridge-scaffoldings, composed of thousands of beams, arms, and parts of iron machines over the shore piers, which are in progress of construction inside of strong caissons. In the midst of the river, 500 feet from either shore, and 520 feet distant from each other, we see the same scaffoldings, only more complicated and more lofty, and, notwithstanding their colossal size, affording an almost elegant spectacle in their wonderful symmetry. Structures of all kinds, and palisades that go down a hundred feet into the river, intended to break the current, and more particularly the floating ice in winter, surround these wonderful constructions that rise from the bosom of the river.
Like the building yards on shore, and even more than these, they are crowded with a perfect bee-hive of engineers and workmen, whose selfconscious ability is infinitely increased by the enormous mechanical powers which stand here ready for use at every step, in the form of floating derricks, steam engines, pumps, and hydraulic jacks. These are the building yards of the two piers. Under these scaffoldings and iron constructions the heavy masses of stone which are intended to carry and hold the three arches of the bridge mostly counterparts of the ponderous structures of the ancient Egyptians, are put together. But how much easier was the task of those ancients, who piled up their edifices in the familiar element of atmospheric air! In our case they had to penetrate into the deeps, but not, like the miner, into the solid element of the earth; they had to break through a volume of water thirty feet deep, and, after arriving at the bottom, to burrow through the sixty and ninety-feet thick layers of treacherous, ever-changing Mississippi sand, in order to rest the basis of the piers upon the eternal ribs of the earth itself, on the rocks of primeval worlds.
The investigations of years in regard to the undercurrent of the Mississippi have shown that no river in the world changes its sand-bed so rapidly and to such an extent; and more particularly the soundings that were made near St. Louis showed that at times, when the river overflows, its sand-layers may be carried away to the depth of forty feet, and, under extraordinary circumstances, scoured down to the very rock itself. Thus was demonstrated the necessity of laying the basis of the piers upon the rock itself, which under one pier is ninety feet, under the other one hundred and twenty feet, under the ordinary high-water line. Inasmuch, on the other hand, as the law of Congress, made in the interest of navigation, prescribes that the height of the arches shall be fifty feet above the city directrix, or ordinary high-water line of the
river, it results that the entire height of the piers must reach 165 and 194 feet respectively.
The system by which the base is laid upon the rock is that of sinking. On colossal iron caissons (open below and resting upon the sand itself), which, with the increasing weight of the piers built on top of them, and as the sand under them is removed to the upper world, sink deeper and deeper, this lowering is effected. In order, however, to render the caissons-which, in spite of the thickness of their iron walls and their solid construction, might not be able to withstand the pressure of the growing masonry and the masses of sand that press against their side walls-capable of resistance, the atmosphere, by means of enormous air-pumps, is compressed in them in such a manner that their power of resistance can be increased to meet any exigency. When the caisson or air-chamber, as it is called with propriety, strikes upon the rockthat is, when the sand-pumps working it have removed the gigantic layers of sand through which it had to penetrate, and when the pier that rests on the caisson is separated only by the air-chamber from the rock-then it (the caisson) is filled with concrete, which completes the indissoluble connection between pier and rock. When the last particle of compressed air in the airchamber bas given place to this indestructible compound of cement and stone, all that remains to be done is to fill up in a similar manner the perpendicular shafts which communicate between the air-chamber and the upper world, and the whole structure of the pier in solid compactness, incorporated with the rock far below, stands aloft, bathing high above its colossal and yet elegant form in the rays of the sun, out of the floods of the river.
IN THE AIR-CHAMBER.
During the last few months a visit to one of the air-chambers under the piers was one of the principal attractions that St. Louis had to show to visitors. The further the piers themselves advanced-that is, the deeper the air-chamber sunk with its burden-the greater was the compression of the air necessary to render them capable of supporting the immense weight which increased with every inch of sinking, and all the harder was the work inside the caisson. When the air-chamber of the east pier, on the 28th of February last, reached the depth of ninety-five feet under the bed of the river, with a weight of 20,000 tons upon it, the workman who removed the last of the sand had to work under the pressure of three atmospheres; and it was not possible so entirely to avoid all kinds of mischances, as has hitherto been the case, without changing the workmen as frequently as possible. In order to afford a more completo under. standing of the matter, we must remark that the introduction of the compressed air into the caisson can be measured with such wonderful accuracy that the sinking can be regulated to an inch. This sinking is accurately calculated according to the quantity of the sand removed from beneath the air-chamber, which is nine feet high. The sand itself is removed by means of powerful pumps, which pump up the sand in great streams after it has been softened and brought in the condition of drifting sand by means of water supplied from a hose, and then driven back to the river from whose depths it had been taken.