Engineers of Dreams: Great Bridge Builders and the Spanning of America - Henry Petroski (1996)

II. EADS

James Buchanan Eads was born on May 23, 1820, in Lawrenceburg, Indiana, which is in the southeastern part of the state, near the Ohio border, just a few miles west of Cincinnati, and, like that Queen City, on the Ohio River. The third child of Ann Buchanan and Thomas C. Eads, he was named after his mother’s young cousin, soon to be a Pennsylvania congressman, who in 1857 would become the fifteenth president of the United States. Thomas Eads was a businessman looking for a business in which to succeed, and this led the family to move first just up the Ohio River to Cincinnati; then, when James was nine years old, down the Ohio to Louisville, Kentucky; and, finally, farther down the Ohio, along southern Illinois, to where the Ohio meets the Mississippi, and up that legendary river to St. Louis.

The accident of his birthplace and his forced travel on two of the most important waterways of the time seem to have greatly influenced young Eads, and he would spend most of his adult life engaged in pursuits that would keep him over, in, under, and around water. He would devise some of the grandest schemes of the nineteenth century to raise great masses of sunken riverboat cargo from the bottom, to flush the silt and sand from the entire middle of a continent out the mouth of the Mississippi, to build a bridge over a river that many said could not be crossed, and to carry fully laden oceangoing ships across the land between the seas. Of these dreams of James Buchanan Eads, only the last was not to be realized.

Young James, his two sisters, and their mother actually went ahead to St. Louis in September 1833, where she was to set up a household before the father arrived to open a general store in the bustling city. James is reported to have been fascinated by the riverboat voyage, and by the vastness and vitality of the Mississippi River. He is said to have told his mother then that he would build a steamboat in St. Louis, which seemed a reasonable ambition for a boy who had already built a model of a steamboat able to cross a pond, as well as models of steam engines, sawmills, and fire engines, in a small workshop that his father had fitted out for him in Louisville. The young lad is said also to have whispered something to himself on the Mississippi on the way to St. Louis, something that even his mother might have found more an idle dream than a possibility: “This is going to be my river.”

First, however, the Eads family was to be the river’s, for, while they lay asleep on the last night of their voyage, as the riverboat approached St. Louis, a fire broke out on board. To escape the smoke filling the confined spaces of the boat, the passengers rushed to the railing, from which they could see the city before them and feel the fire behind. The boat did remain afloat until it reached the dock, upon which the Eads family and other passengers then stood helplessly watching their possessions go up in flames. However, with the few resources with which she had escaped, Mrs. Eads was able to rent the upstairs of a house that faced the river. It was evidently large enough for her to take in boarders and so bring in some income.

Although he had attended school up until that time, thirteen-year-old James could not continue his education in St. Louis, because he had to work to help support his family. At first he sold apples to bring home some money, but soon he found a more substantial opportunity as a “boy-of-all-work” in the Williams & Duhring dry-goods store run by Barrett Williams, one of the men who took meals at Mrs. Eads’s boarding house. James was evidently a bright, energetic, and well-mannered employee, to whom Williams took a liking. Thinking it a pity that someone like young James could not go to school, Williams gave his loyal worker the run of his library, which was located in a room above the store. James was told that in his spare time he could read at will among the books, which included works on physical science, mechanics, machinery, and civil engineering.

Had young Eads wanted to study engineering formally at this time in America, he would have had virtually no opportunities close to home, and thus it is hard to imagine a better opportunity, especially in the St. Louis area, than the one given him by Barrett Williams. Though an engineering school had been called for by General George Washington as early as 1778, the Military Academy did not become firmly established at West Point until 1802. There were only the beginnings of a few other formally established courses in engineering in the early 1830s, let alone schools where a young man like James Eads could get a degree in civil engineering.

There were, of course, the likes of the Franklin Institute, established in Philadelphia in 1825, where lectures on applied science and mechanics were offered, often in the evening and aimed toward individual betterment rather than toward a degree. Also, up and down the East Coast, there were the beginnings of what might have developed into engineering schools. In Vermont, in 1819, Alden Partridge, who in 1813 at West Point had become the first individual to hold the title of professor of engineering in the United States, established the American Literary, Scientific and Military Academy, which later was renamed Norwich University. Courses in civil engineering were offered there as early as 1821. In Maine, in 1822, Robert H. Gardiner started a lyceum that bore his name and offered courses of study preparatory to engineering, but it survived for barely a decade.

The most sustained effort was begun in 1824 at Troy, New York, by Stephen Van Rensselaer, who, as lord of over three thousand farms totaling almost half a million acres in New York’s Rensselaer and Albany counties, was “the last patroon in full authority.” Van Rensselaer founded the Rensselaer School “to qualify teachers for instructing the sons and daughters of farmers and mechanics, by lectures or otherwise, in the application of experimental chemistry, philosophy, and natural history, to agriculture, domestic economy, the arts and manufactures.” By 1835, the Rensselaer Institute was authorized by the New York State Legislature to give instruction in “Engineering and Technology,” and the new degree of “civil engineer,” the first such in Britain or America, was granted that same year, to a class of four. By 1849, Rensselaer was the leading civilian engineering school in the country.

In the South, engineering was taught at the University of Virginia, which Thomas Jefferson had established in 1814 to teach natural philosophy, military and naval architecture, and technical philosophy. The first course in civil engineering at Virginia was offered by one of the school’s original faculty members, Charles Bonnycastle, in 1833. He was joined in the newly established School of Engineering in 1835 by Barton Rogers, who in 1865 would become the first president of the Massachusetts Institute of Technology. Instruction in civil engineering was begun at the University of Alabama in 1837 by order of the board of trustees, who saw it as beneficial to the growth and maintenance of an increasingly important railroad network throughout the South. Among its first professors was Frederick Augustus Porter Barnard, who eventually became president of Columbia University. A School of Civil Engineering was begun at the College of William and Mary in 1836; Virginia Military Institute, which was modeled after the famous French Ecole Polytechnique, was started in 1839; and the Citadel was established in 1842 to teach both military and civil engineering.

But young James Eads was in no position even to dream of attending such schools. The more common route to becoming an engineer throughout the first half of the nineteenth century was to work on a project like the Erie Canal, begun in 1817, “completed” in 1825, and widened, deepened, and extended in the 1830s, when it had become jammed with traffic. Accordingly, “many of the fledgling surveyors and assistants who planned and completed the canal ‘graduated’ from the project as highly skilled engineers.” Young men of more substantial means did go to Europe to study, rather than build, the great works of engineering, or specifically to France to learn engineering from a still more theoretical point of view. Many an engineer of the early nineteenth century also absorbed a great deal from his self-taught father.

One such engineer was Loammi Baldwin, who became widely known for his hydraulic works, and who was responsible for the navy drydocks at Charlestown, Massachusetts, and Norfolk, Virginia. Even though it would be said that he had “learned engineering through self-study and by working under his father, Loammi Baldwin I, on the construction of the Middlesex Canal,” the younger Baldwin also studied mechanical subjects at Westford Academy, was a member of the class of 1800 at Harvard, and studied law. He practiced engineering before being admitted to the Massachusetts bar, then operated a law office in Cambridge from 1804 to 1807, and finally abandoned law to return to civil engineering. Following a visit to Europe to inspect public works, he opened an engineering office in Charlestown and became involved with the extension of Beacon Street beyond the Boston Common, the Union Canal, and other significant works. Though steeped in practical experience, he was also among the earliest of American engineers to call for state-supported schools to teach engineering theory.

Baldwin spent the period 1824–25 in a concerted effort to enlarge his father’s civil-engineering library by augmenting it with British and French books, and he strongly advised that anyone “who would become an engineer must collect books.” Although the young James Eads was in no position to buy, let alone collect, books, he did have access to Barrett Williams’s library, where he could read well into the night. In this way, Eads, like many of his contemporaries, was able to lay the theoretical foundation for his own engineering education, which in his case would be completed on the river.

In time, the elder Eads joined the family in St. Louis, and his general store prospered modestly. But the restless Thomas Eads, evidently not content with that business venture, went into partnership with another man to buy some property up the river, near Davenport, Iowa, where they planned to open a hotel. In the meantime, eighteen-year-old James had become a salesman at the dry-goods store and elected to stay in St. Louis, where he had some cousins, and where he knew he had a steady income and the run of a fine (if necessarily limited) library. Before too long, perhaps when he began to exhaust the resources of Barrett Williams’s books, James was drawn again to the river, and he signed on as a second clerk on the steamboat Knickerbocker. On a voyage, while rounding the bend from the Mississippi into the Ohio, the boat hit one of the countless snags in the water and went down.

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The Mississippi River was notorious for claiming boats laden with personal and mercantile treasures, and Eads had had plenty of time while clerking on the Knickerbocker to reflect upon what was beneath the muddy waters. Many a person realized that whoever could salvage even a small fraction of the treasure sunk there could make a fortune, for shippers and insurance underwriters would pay anywhere between 20 and 75 percent of the net value of cargo salvaged, and anything sunk more than five years became the property of whoever could raise it. However, the treasure was elusive, for the constantly shifting sandy bottom of the river quickly covered up wrecks and their cargo and made them very difficult to locate—never mind to raise.

When he was twenty-two years old, Eads conceived of a scheme that would enable a diver to work underwater for extended periods of time, thereby allowing him not only to walk about the river bottom and locate wrecks but also to free valuable cargo. Eads effectively worked as an engineer by developing, in his head and on paper, the early ideas for his “sub marine” and diving bell. What he had read in Barrett Williams’s books may have given him full assurance that enough air pressure could be pumped to a submerged diver to make the concept work, but since Eads did not possess the capital to realize the scheme by himself (a position quite familiar to engineers with dreams grander than their material resources), he took his design to potential investors and other entrepreneurs. In 1842, Eads approached Calvin Chase and William Nelson, St. Louis boatbuilders, and offered them a partnership. His investment would be the idea and the operation of the salvage craft, theirs the capital and experience to build the boat. They agreed, and Eads soon began the first of over five hundred explorations on the river bottom.

Eads’s scheme involved the use of a modified snag boat, a double-hulled craft familiar on the Mississippi and so named because it was used to remove the many obstacles, or snags, that developed in the water. A diver was to descend to the river bottom in a diving bell supplied with air from the boat that served as the base of operations on the water. Divers had used diving bells successfully in calm lakes, and Eads engaged an experienced man to help him try out the scheme over a sunken barge loaded with about a hundred tons of pig lead. However, the swift currents of the Mississippi proved too much for the light equipment, and the diver found it difficult to maintain control underwater. Seeking a means of improving the operation, Eads went to the nearby town of Keokuk and obtained a forty-gallon whiskey barrel; he weighted its top down with a few hundred pounds of lead, and across its open bottom he attached a strap upon which the diver could sit. When the designated diver declined to use the contraption, Eads himself descended in what must have looked like so many mad Victorian inventions that would be illustrated years hence in the pages of Scientific American. He successfully gathered a quantity of lead into the barrel before signaling to be hoisted up, but by then he had ranged so far from the snag boat that the line to the derrick on the boat was overextended, and it capsized in the process. There were a few anxious moments before Eads was hauled to safety by hand, but once out of the water he commenced to modify the procedure and make improvements in the salvaging system. Future snag boats would carry not only an air pump but also a sand pump to expose wrecks and their cargo, in addition to heavy hoisting machinery to bring up safely the diver, the loot, and, in later modifications, whole riverboats.

Not only did Eads and his partners make a fortune in the salvage business, but he grew to know the nature of the river bottom between St. Louis and New Orleans perhaps better than any of his contemporaries. He was intimately familiar with the stretch of river below Cairo, Illinois, where he once spent four hours a day for two months, Sundays excluded, walking back and forth over a three-mile stretch of the river, until he found the wreck of the Neptune. Years later, in his 1868 report as engineer-in-chief of the Illinois and St. Louis Bridge Company, he would write from experience of the action of undercurrents and other phenomena along the river:

I had occasion to examine the bottom of the Mississippi, below Cairo, during the flood of 1851, and at 65 feet below the surface I found the bed of the river, for at least three feet in depth, a moving mass, and so unstable that, in endeavoring to find footing on it beneath the bell, my feet penetrated through it until I could feel, although standing erect, the sand rushing past my hands, driven by a current apparently as rapid as that at the surface.…

It is a fact well known to those who were engaged in navigating the Mississippi twelve years ago, that the cargo and engine of the steamboat America, sunk 100 miles below the mouth of the Ohio, was recovered, after being submerged twenty years, during which time an island was formed over it and a farm established upon it. Cottonwood trees that grew upon the island attained such size that they were cut into cord-wood and supplied as fuel to the passing steamers. Two floods sufficed to remove every vestige of the island, leaving the wreck of the America uncovered by sand and 40 feet below low-water mark.…

This kind of knowledge and experience would be invaluable later, when Eads had to determine how deep the piers would have to go to support a bridge over the Mississippi at St. Louis, and, still later, how to channel the waters at its mouth so that it would remain navigable past New Orleans and into the Gulf of Mexico. By observing the motion of the river bottom at many locations and under various conditions, he was able to formulate an unsurpassed theory of its behavior.

When he was not working on or in the Mississippi, Eads would sometimes return to St. Louis to visit his cousins Susan and Martha Dillon, especially Martha, whom he wished to marry. Although the salvage business was profitable, her father questioned James’s financial and physical future in so risky an endeavor, and the marriage did not occur till 1845, after Eads had sold his part in the salvage business to invest in the land-based enterprise of running the first glassmaking factory west of the Mississippi. However, a poor financial climate and a scarcity of skilled workmen soon put Eads $25,000 in debt, and he returned to the salvage business in 1848.

James and Martha had two daughters and a son, but the boy lived only about a year, and Martha died of cholera shortly thereafter, in 1852, leaving Eads heartbroken. He immersed himself in work and became very rich and famous, but soon his own health began to deteriorate, and he was ordered by doctors to take a complete rest. He married his cousin’s widow, Eunice Eads, traveled to Europe, and came back to work on the river again. After three more years, however, at the age of thirty-seven, with the Eads & Nelson Sub Marine No. 7 raising wrecks of all kinds, and with the salvage business one of the most prominent in the country, Eads became exhausted and was forced to retire. He did so in St. Louis, where he entertained some of the most famous visitors to the city and talked of politics, secession, and slavery, which Eads opposed. He did not agree with his second cousin, James Buchanan, who was then in the White House, on the Dred Scott decision, and when the Civil War came, Eads was happy that Missouri voted not to leave the Union.

Soon after the surrender of Fort Sumter in 1861, Eads, the expert on Mississippi River craft, was summoned to Washington by his friend Attorney General Edward Bates, for a conference regarding the use of gunboats on the river. Eads recommended that a base be established at Cairo, Illinois, that Confederate commerce be blockaded, and that a snag boat be converted into an armed steamer protected by cotton bales. The proposal was referred to the War Department, but instead of a snag boat three wooden steamers were employed as the nucleus of the Mississippi fleet. Eads became the successful bidder to build seven five-hundred-ton, 175-foot-long armored wooden gunboats, whose hulls were to be divided into fifteen watertight compartments, and whose boiler and engines were to be protected with iron plates two and a half inches thick. Though the boats were supposed to be completed in two months, the last of them took over twice that time to finish.

The first gunboat completed, the St. Louis, was launched on October 12, 1861, and fought in the battle against Fort Henry on February 6, 1862, thus predating the more famous battle between the ironclads Monitor and Merrimac by over a month. In the meantime, independent of the War Department, General John Charles Frémont ordered the conversion of two steamboats to ironclads. Thus Eads was able to implement his own plans to convert a snag boat, which resulted in the “most powerful of the western ironclads,” the Benton, with sixteen guns protected by as much as three and a half inches of iron. He later wrote to President Lincoln that “the St. Louis was the first ironclad built in America. She was the first armored vessel against which the fire of a hostile battery was directed on this continent, and so far as I can ascertain, she was the first ironclad that ever engaged a naval force in the world.”

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Before the war, the Baltimore & Ohio Railroad had reached Illinois Town, later known as East St. Louis, Illinois, thus establishing a continuous rail line from the East to the Mississippi River. Proposals followed to build a bridge across the Mississippi into St. Louis, Missouri, thus opening a rail route to the West that would compete with the one through Chicago. It would be hard to say when exactly the first idea for a bridge might have crossed anybody’s mind, but as early as 1839 at least one engineer had not only thought about it but done enough preliminary calculations to write to William Carr Lane, the mayor of St. Louis, outlining a proposal for a bridge that would cost no more than 00,000 to erect.

Charles Ellet, Jr., was born in Penn’s Manor, Pennsylvania, in 1810 and studied in Paris at the Ecole Polytechnique before commencing engineering work on railroads and canals in America. Around 1836, he turned his attention to the study of suspension bridges, perhaps inspired by the completion in 1834 of the 870-foot wrought-iron wire suspension bridge across the Sarine Valley at Fribourg, Switzerland, then the longest bridge span in the world. In 1842, Ellet would complete the Fairmount Bridge across the Schuylkill River in Philadelphia, the first suspension bridge in America to employ strands of wire rather than iron chains or eyebars to hold up the roadway, and in 1849 he would build the record 1,010-foot-span wire suspension bridge across the Ohio River at Wheeling, West Virginia. The deck of this latter bridge was to be destroyed by the wind in 1854, but in his 1839 proposal for St. Louis, Ellet had the utmost confidence in such designs.

Upon receipt of Ellet’s letter, the mayor submitted it to the members of the St. Louis City Council with the request that a committee report on the proposal. Since the mayor noted that “Mr. Ellet promises leaving the city in a few days,” a speedy report was clearly his wish, and the joint committee of three delegates and two aldermen reported within six days. According to Calvin Woodward, dean of the Polytechnic School of Washington University, in his definitive history of the St. Louis Bridge published in 1881, the committee’s recommendation was to accept Ellet’s “proposition to make surveys and soundings, and to furnish full drawings and estimates, and present three hundred printed copies of the same to the city for the sum of $1,000.”

Ellet evidently stayed on in St. Louis to investigate three possible locations for his bridge, all of which had rock on the St. Louis side of the river, thus ensuring firm foundations there. In midstream and on the Illinois shore, he found that the sounding auger could not be driven more than twenty feet below the water, and thus Ellet reported that the riverbed was “superior to the soil which sustains some of the most celebrated stone bridges in Europe” and firm enough to drive piles into for the foundations of piers. The proposed bridge was to have three towers, with a central suspended span of twelve hundred feet and two side spans of nine hundred feet each. The length of cables required would thus be within the limits of a suspension bridge, which Ellet calculated to be one and one-fifth miles, and for the Mississippi spans he specified ten cables, each comprising twelve hundred one-eighth-inch-diameter wires gathered into a cylinder of about five inches in diameter. Though the final estimate of $737,566 was less than 25 percent higher than the original one, which they seem not to have balked at, the mayor and City Council used cost as an excuse to reject what they must have feared was an overly ambitious technical scheme: “The time is inauspicious for the commencement of an enterprise involving such an enormous expenditure of money.” Their instincts were correct, of course, for, as Eads would soon discover on the turbulent bottom of the Mississippi River, the foundations of Ellet’s bridge would have been scoured away, possibly even before the cables were in place.

The state of bridge building at midcentury was changing as rapidly as the bed of the river itself. As the railroads spread their routes throughout Britain, America, and elsewhere, they came to use ever heavier and more powerful locomotives to carry ever-increased loads, and thus the suspension bridge was generally thought to be too flexible and too susceptible to wind damage to be considered a viable and reliable railroad structure. This is what led Robert Stephenson, in the mid-1840s, to design and build in northwestern Wales a revolutionary bridge type of such massive proportions and strength that it carried trains not over but through its great tubular girders, which spanned almost five hundred feet between piers and about fifteen hundred feet total over the Menai Strait. The Britannia Bridge was a marvel of engineering, but it was an extremely expensive undertaking, costing a total of 600,000 pounds sterling by the time it was completed in 1850, and so improvements, by way of spanning similar distances with lighter structures, became imperative. Yet, though British engineers like Isambard Kingdom Brunel and Thomas Bouch designed lighter and lighter girder bridges that carried heavier and heavier railroad trains, the British generally shied away from the suspension bridge for railway applications. Some Americans, however, did not.

The Britannia Bridge, in northwestern Wales, with the Menai Strait Suspension Bridge visible about a mile to the north (photo credit 2.1)

John Roebling was educated as an engineer in Germany, having received a degree in civil engineering from the Royal Polytechnic School in Berlin in 1826, but for philosophical reasons he emigrated to America in 1831 with the intention of starting an agrarian community. He settled first in western Pennsylvania; when the utopian experiment did not work out, he turned to manufacturing wire rope for towing barges on canals and some small suspension bridges that carried the canals over rivers. In 1841, he published a paper discussing the “comparative merits of cable and chain bridges,” in which he described many of the then widely known failures of suspension bridges, arguing that the incidents showed an engineer what he had to design against. By 1854, Roebling had completed a bridge with an 810-foot span over the Niagara Gorge, which demonstrated incontrovertibly that an efficient and economical cable suspension bridge could indeed be built to carry heavy railroad trains. Shortly after the Niagara Gorge Suspension Bridge was completed, Roebling proposed a very long-span suspension bridge over the Mississippi at St. Louis, but there was not sufficient financial support for any kind of bridge at that time. More than a decade later, Roebling would propose several other designs, including combination suspension-and-arch types, but there was little support for these proposals either.

After the Civil War, however, the City Council declared that it had “become indispensably necessary to erect a bridge across the Mississippi River at St. Louis, for the accommodation of the citizens of Illinois and Missouri, and the great railroad traffic now centering there,” and the city engineer, Truman J. Homer, was instructed to draw up possible plans and estimate costs. He did report, only four days later, and was able to make a recommendation based on an idea he had actually conceived several years earlier and had since spent “much thought and extended inquiry upon.” Homer condemned suspension bridges and proposed the building of a tubular bridge, slightly larger than Stephenson’s Britannia, with carriageways on either side of the main tube and footpaths above it. For forty-nine weeks of the year, the clearance above high water would have been at least forty-four feet; Homer argued that steamboats could pass under such an obstruction, and that, in any case, the chimneys of steamboats could be made so they could be raised and lowered at will. The cost of Homer’s tubular bridge was given at over $3 million. An earlier scheme, proposed by the Mississippi Submerged Tubular Bridge Company, for a tunnel under the river, might have cost even more. Neither was built.

The urgency for a bridge at St. Louis had been driven by earlier developments elsewhere. In 1856, the first rail bridge across the Mississippi was completed at Rock Island, Illinois, which was just about due west of Chicago, on the Chicago & Rock Island Railroad, thus promising an uninterrupted route westward. St. Louis boatmen reacted by filing lawsuits, “charging that bridges across navigable waterways were public nuisances, navigation hazards, and unconstitutional restraints on interstate commerce.” In the meantime, the river had also been bridged by railroads at Dubuque and Burlington, Iowa, and at Quincy, Illinois, only a hundred or so miles upriver from St. Louis. The Missouri River was also bridged, at Kansas City, thus allowing St. Louis to be bypassed entirely by railroads on the way to its historic trade territories. Although complaints were rising that “it cost nearly half as much to ship a barrel of flour fifteen hundred feet across the river as it did to ship it upstream twelve hundred miles from New Orleans,” ferryboat interests at the city without a bridge insisted they could continue to serve St. Louis commerce by floating entire railroad cars across the Mississippi on barges. However, the expenses and interruption of continuous rail service created bottlenecks in Illinois Town, and business was lost to the northern routes. One newspaper editor is reported to have said that geography had been undone by technology.

Even though the population of St. Louis was on a par with Chicago’s two hundred thousand in the mid-1860s, in the commercial race the Missouri city was trailing and falling further and further behind. Illinois ranked second in railroad-track mileage in the early 1860s; Missouri was fifteenth among the thirty-seven states, with only 983 miles laid by 1867. Still, there were five railroads from the east and three from the west converging on St. Louis, and no continuous river crossing to serve them. Local newspapers and civic leaders began frantically to call for a bridge, which they argued not only would help St. Louis replace Washington, D.C., as the nation’s capital but also would enable it to become “the future Great City of the World.”

Neither in the heat of community boosterism nor in calmer times can bridges be erected wherever one pleases. In order to throw a bridge over a navigable waterway between two states, one has first to secure the appropriate enabling legislation. Thus, as an initial step, bridge promoters had obtained a charter for the St. Louis and Illinois Bridge Company, having secured the authorization of the two states in 1865 and that of the federal government in 1866. Like many a bridge charter, this one made certain specifications about the structure, which “might be a pivot or other form of drawbridge or else one of continuous spans.” If the bridge did not pivot or open, it had to have spans of no less than 250 feet and it had to provide no less than forty feet of headway above the city directrix, which was a curbstone at the foot of Market Street indicating the level that record flood waters had reached in 1828, and which defined “the datum plane for all city engineering in St. Louis.”

James Buchanan Eads, as he was pictured in A History of the St. Louis Bridge (photo credit 2.2)

It was not uncommon, once one private company was formed to build a bridge and obtained a charter, that a rival firm soon also was established and sought a charter of its own. In the case of St. Louis, the competition was embodied in a Chicagoan, Lucius Boomer, and his Windy City backers. They exerted pressure on the Illinois Legislature to rescind the charter of the St. Louis and Illinois Bridge Company and give Boomer’s deliberately named Illinois and St. Louis Bridge Company the exclusive right for twenty-five years to build a bridge from the Illinois shore. If such a bridge were actually built, toll revenues would effectively flow from St. Louis business interests to Chicago investors. Even if Boomer’s group did not complete a bridge, or if it sold its charter to St. Louis steam- or ferryboat operators, the effect would be to cause St. Louis to fall further behind Chicago in mercantile activity.

Among the contemporary movers and shakers in St. Louis was James Buchanan Eads, whose interest in bridges to this time was mainly in how they might obstruct the waterway. However, he took the potential commercial threat from Chicago as a call to action, and since a bridge was believed to be inevitable, he encouraged support of the original, and local, bridge company. A committee went to the Illinois state capitol in Springfield to lobby against what came to be known as the Boomer bridge bill. Southern Illinois legislators, who understood the importance of St. Louis to their own economic future, helped to get compromise legislation passed specifying that the exclusive building rights of Boomer’s firm would lapse if a bridge was not begun in two years or finished in five.

Early in 1868, Boomer began to make noises about what kind of bridge his company would build. An earlier bridge of his had collapsed in 1855, killing Calvin Chase, one of Eads’s original salvage partners, along with many other prominent St. Louis businessmen and politicians en route to a convention in Jefferson City. This time Boomer involved a consulting engineer, Simeon S. Post, of Jersey City, New Jersey, whose reputation was sound; his proposed bridge was to consist of six spans of an iron-truss design he had patented in 1863. The term “truss” designates any arrangement of beams, rods, cables, or struts that are connected together to form a rigid framework, thus enabling relatively long and stiff bridges to be built with a minimum of material. Wooden-roof trusses are of such construction, but, perhaps because they are concealed, they were an often overlooked kind of bridge. The idea of a truss as a bridge in its own right had been made explicit in the Renaissance.

In his sixteenth-century book on architecture, the Italian architect Andrea Palladio illustrated the wooden truss as a “most beautiful contrivance.” In eighteenth-century England, wooden bridges resembling Palladian designs came to be called “mathematical bridges,” presumably because of the forethought and calculation that had to precede the cutting, assembling, and bolting together into an effective structure of the many different wooden pieces. Today, the Mathematical Bridge that allows the residents of Queens’ College a very convenient route across the River Cam is one of Cambridge’s tourist sites and one of the most photographed, sketched, and painted of its structures.

A truss bridge and some terminology used to describe its various parts (photo credit 2.3)

A variety of truss types employed in bridges (photo credit 2.4)

With the increasing production and application of iron in the nineteenth century, trusses naturally evolved into a plethora of types and styles employing the new material. Iron-truss bridges, unlike the Britannia tubular bridge, were relatively light and open structures, and yet, if properly designed, were just as well suited to carrying heavy railroad trains. How to arrange the various parts of a truss was the subject of many patents dating from the 1840s on, and Simeon Post’s patented design incorporated modular arrangements of iron rods and struts. Like most patents, this was an improvement on the prior art. Post’s arrangement of the components allowed for the expansion and contraction of the iron so that traffic and temperature changes would “not produce injurious effects upon the structure, and in this manner obviating one of the most serious objections to the universal use of such bridges.”

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James Eads had never built a wooden bridge, let alone one of iron, and perhaps he had never even dreamed of doing so. His interests were more in and on the water than over it. Indeed, to Eads, putting the piers of a bridge in the water meant providing obstacles to river traffic, as did the superstructure they supported, but his concern for the commercial future of St. Louis overcame his preference for an unobstructed river. He never did lose sight of the importance of river traffic to the city, however, and so he could not imagine or endorse any bridge design that would have obstructed the waterway more than it had to, even temporarily during construction. Thus Eads would certainly have balked at the traditional means of building stone-arch bridges and even some of the newer iron-truss bridges, whereby a timber scaffolding known as “centering” or “falsework” needed to be erected first, and might have to remain in the main waterway for an unconscionable length of time until the great bridge being assembled atop it reached the point where the stone or ironwork was self-supporting and the centering could be struck or the falsework disassembled.

As early as 1866, Eads’s recommendations for bridge legislation included a minimum width of six hundred feet between piers and a minimum headroom of fifty feet above high water, “measured in the center of the span,” to minimize interference with river traffic. Such a specification, which effectively ruled out a truss bridge of any kind, may well have reflected Eads’s reading of the unrealized proposal made early in the century by the British engineer Thomas Telford for an iron arch to provide a clearance of sixty-five feet above the water at the crown while spanning six hundred feet over the Thames River at London. Legislation as strict as Eads’s suggestion did not pass, but a minimum span length for a crossing of the Mississippi below its confluence with the Missouri, just above St. Louis, was fixed at five hundred feet. This was the size arch Eads himself eventually proposed to build.

Even though no arch greater than about four hundred feet had ever actually been constructed, the reputation of Telford, who was the first president of the Institution of Civil Engineers and who is buried in Westminster Abbey, made his dream almost as good as reality, at least to Eads; besides, the iron bridges of modest span that Telford did complete in Wales and Scotland were masterpieces. However, aesthetic models were ideals to be challenged by competition and economics. A convention of civil engineers, including Post, which was lavishly hosted by Boomer in St. Louis in August 1867, praised his bridge proposal while cautioning investors that Eads’s had “no engineering precedent.” Eads countered with an appeal to Telford’s generally acknowledged sound judgment and authority, which he felt did indeed provide “some ‘engineering precedent’ to justify a span of 100 feet less,” six decades later. He went so far as to state that it was “safe to assert that the project of throwing a single arch of cast steel, two thousand feet in length, over the Mississippi, is less bold in design, and fully as practicable, as his cast iron arch of 600 feet span.” Eads’s own reputation for sound engineering judgment, albeit with projects other than bridges, and his confidence, coupled with Boomer’s increasingly transparent attempts to manipulate public opinion, led to negotiations between the two rival bridge companies, which consolidated in 1868. Their stock was combined, a new board of directors was formed, with equal representation from each side of the river, and the name Illinois and St. Louis Bridge Company was adopted, with Eads as engineer-in-chief.

Thomas Telford’s 1800 proposal for an arch bridge across the Thames (photo credit 2.5)

Some insight into what must have helped sway support to Eads can be gained by reading his report of May 1868 to the president and directors of the company, in which he consistently writes of “your Company” and “your Bridge.” As are virtually all reports by successful entrepreneurial engineers like Eads, the twenty-five-thousand-word document is technically concise and sound, a model of clarity and persuasion, and totally accessible to the general reader. Eads said as much in his opening statement to the directors:

In view of the great importance of your enterprise, the deep interest manifested in it by our citizens and the public generally, and because the plans adopted by you have been frequently misrepresented and unfairly criticised, I have deemed it proper that everything of interest connected with my department should be placed in such form as to be clearly understood, not alone by your stockholders, but also by every person of ordinary intelligence in the community. I have, therefore, endeavored to explain the plan of the structure, the principles involved in its construction, and the reasons for its preference, in the simplest language I can command, and with an avoidance, as far as possible, of the use of all technicalities not understood by every one.

Under the topic of location, Eads explained why his bridge was to be sited at Washington Avenue, rather than a few blocks north, where “Mr. Boomer’s bridge” was to be located. The convincing arguments had to do with access to the center of population in St. Louis, the pre-existence of streets that were able to absorb all the traffic that would concentrate at the bridge approach, the cost of the connecting tunnel needed to carry the railroad trains through the center of the city without interfering with carriage and foot traffic, and the location along the wharf that would minimize interference with riverboats. Eads also led the reader through an elementary discussion of the principle of the lever in order to demonstrate “the economy of the arch, over the truss, for long span bridges.” In fact, Eads saw the arch as a kind of limiting case of the truss, with stone abutments serving to take the thrust that in a truss would otherwise have to be resisted by increasing amounts of iron, which naturally added weight and thereby cost to the structure.

To show that his bridge design was not “needlessly extravagant,” Eads proceeded to illustrate “enough of the general principles involved” in bridge building to allow “anyone with ordinary intelligence” to judge for himself the value of the arch over the truss for the St. Louis crossing. He began his remarkably concise and well-illustrated exposition with the “simplest of all the mechanical powers, the lever,” which is familiar to everyone in the form of a simple balance scale. The action of a large weight on a short arm is balanced by a small weight on a longer arm, with the ratios of weights and arm lengths simply related to each other. If the short arm of the lever was bent, or canted, relative to the long arm, Eads argued that the same ratio of pulls or pushes was necessary to maintain equilibrium, and the supporting wall or abutment into which the canted lever was anchored could supply whatever force was needed. This canted-lever principle was the same as that articulated by Galileo in his seventeenth-century investigations into the strength of materials, and it would play a central role in bridge building later in the nineteenth century. But for Eads in his 1868 report to the president and directors of the Illinois and St. Louis Bridge Company, it was only a means to an end.

Three figures from the report of James B. Eads, showing the principle of the lever, the “canted lever,” and hack to hack canted levers tied together by a lower chord to make a truss bridge (photo credit 2.6)

Eads next argued that, if two canted levers were placed tip to tip, with their short arms resting on piers and tied together with a structural element known as a chord, there would result an elementary truss bridge, in which the pull in the chord would be opposed by a compression of the longer lever arms. Like all successful engineers, Eads understood the important and nontrivial practical implications of the truism that the structure worked if it did not fail: “If the upper member fails to resist the crushing force, or the lower one is rent asunder, the truss must fail.” Such simple reasoning provided the basis for calculation of how much material, and hence how much money, was required to build a bridge.

With his explanatory bridge constructed on paper, Eads led his readers to observe that the pair of canted levers could be replaced by slanted straight members connecting one end with the other, thus saving material and money. At this point, the bridge looked like the roof structure of a house, which every reader of Eads’s report must have recognized as a kind of bridge in which they had long had confidence even if they lacked a complete understanding of its principles. As with larger roofs, the simple triangular arrangement has to be supplemented with cross bracing in order to keep the lines of the timbers from bending and breaking under their burden, and hence the familiar roof truss. In the 1860s, however, when railroad bridges had to span much greater distances than roofs, and without the help of excessively high and costly peaks, the flatter bridge truss made of iron evolved. The forces that had to be resisted by the various members of the truss depended upon its proportions, and these in turn affected the cost of the bridge. The proportions of height to length of bridge that would “insure the greatest economy” depended upon the type of truss, and they had been found to vary from about one-to-eight to one-to-twelve, thus making all sorts of bridges share a certain sameness of outline. Indeed, to Eads at least, the term “truss” included “every known method of bridging except the arch,” which provided the ultimate economy.

To use less material than a truss of triangles, the top of the bridge could be curved, thus leading to the “bow-string girder,” and Eads led his readers to observe that its bottom chord became unnecessary, thus reducing the cost, if the bridge piers or abutments could provide the forces to keep the bow from flattening out. However, for such a long bridge as Eads proposed at St. Louis, such an unbraced arch would be too flexible, especially under the action of heavy railroad traffic, and so he argued that it could be stiffened by means of a form of trussing between it and the roadway. Finally, in the ultimate refinement of his argument, Eads replaced the single heavy arch with a pair of lighter arches, themselves trussed together to provide enough stiffness so that the roadway could be supported on lighter members, thus reaching a further economy of materials.

According to Eads, there were two general kinds of arch bridge—the “upright” one, which he reasoned to from the principle of the lever, and the “catenary or suspended arch,” which was otherwise known as a suspension bridge. Even though Roebling’s Niagara Gorge Bridge had carried railroad traffic for almost fifteen years, some disagreement still remained among engineers about the safety of suspended spans. However, there was little doubt that the suspension bridge, or suspended-arch principle, was the most economical means of spanning long distances, such as that over the Mississippi between Illinois and Missouri. Eads addressed the question of upright versus suspended arch later in his report, and he weighed the pros and cons of using iron in tension and compression.

Though the repeated loading of iron in tension, such as occurs in a suspension bridge, was then known to be capable of leading to failure by fatigue, Eads and other engineers understood that they could avoid this by keeping the loading levels sufficiently low; but this meant using more material, and hence resulted in a greater cost. Since the ultimate strength of conventional iron was greater in tension than in compression, in the final analysis the suspension bridge, which relied on the former, was the most economical type for long spans. However, the upright arch, which Eads clearly favored on philosophical if not aesthetic grounds, would become economically competitive with the suspended arch if it could be made of a material whose capacity to carry a load without yielding in compression was not so inferior as was that of iron to its capacity to carry a load in tension. There was in fact a new material that fell into this category; Eads specified that his upright arch be made of cast steel.

As everyone knew, temperatures in St. Louis ranged from well below zero in the winter to well over a hundred degrees Fahrenheit in the summer sun, and this also had to be considered in bridge building. Since iron and steel expand when heated and contract when cooled, a five-hundred-foot arch would rise and fall eight inches with the passing seasons. Similar movements could result from heavy loads crossing the bridge. Uneven heating of the bridge by the sun, or asymmetrical loading of the bridge, could also push and pull it every which way over time. If this kind of potentially destructive movement could not be accommodated, it could destroy abutments, buckle rails and roadways, and eventually tear the structure apart. Eads was clearly concerned about this aspect of his bridge, as indicated in several patents for improvements in bridges that he took out while the bridge was under construction, in the late 1860s and early 1870s. The drawings for the earlier patents, though clearly showing an archlike bridge, are titled “truss bridge,” which further emphasizes Eads’s view of the arch, especially when stiffened, as a supremely efficient limiting case of a truss.

No engineer, in Eads’s day or now, can conceive, promote, design, defend, and build a major bridge without help. A good deal of the attention of an engineer-in-chief like Eads is necessarily taken up in matters of a political, financial, and public-relations nature, and there is not enough time, let alone experience or talent, in one person’s lifetime of days to carry out all the minute calculations and prepare all the detailed drawings that enable the proper parts to be designed, ordered, and assembled into a finished bridge, whether mathematical or not. Early in his report, Eads acknowledged his debt to some of the most important contributors to the engineering endeavor.

Henry Flad was born in Rennhoff, Germany, in 1824. After graduating from the University of Munich in 1846, he worked for the Bavarian government. He served as captain of engineers in the Parliamentary Army during the 1848 revolution, then fled to America. Flad landed in New York City in 1849 and worked there as a draftsman until getting involved with railroad engineering and moving west with the railroads. He enlisted in the Union Army and served in an engineering regiment, rising from private to colonel. After the war, he worked on plans to improve the water supply of St. Louis, and then was engaged as chief assistant to Eads for carrying out “the mathematical investigations and calculations for the Bridge.” Flad was in turn aided in the design by Charles Pfeiffer, who had recently emigrated from Stuttgart, where his thesis on the theory of arch-bridge design had won a prize. Indeed, in addition to his German degree of “civil engineer,” Pfeiffer may also have brought with him the experience of the Koblenz Bridge, completed in 1864, for Pfeiffer “based his first series of calculations on the equations developed for Koblenz and modeled his first sketches directly on the German bridge.” In 1869, Eads and Flad jointly were issued a patent for an “improvement in arch bridges” that relieved the thrust of the arch on its piers, “thus permitting a light construction of such piers.” Like Eads’s earlier patents, the drawing was headed “truss bridge.” A few years later, Flad was issued a patent in his own name for an invention that enabled the stay cables essential to the construction process to be maintained at a uniform tension even as temperature changes affected a bridge structure under construction.

Drawings from one of Eads’s several patents, this one employing the canted-lever principle and showing how broadly he applied the term “truss bridge” (photo credit 2.7)

As Eads, Flad, and Pfeiffer knew, the essence of sound engineering lay in clearly stating the assumptions upon which calculations are based so that they may be checked at all times for lapses in logic and other errors. It is thus imperative that engineering premises be set down clearly, and that the calculations that follow be systematically and unambiguously presented, so that they may be checked by another engineer with perhaps a different perspective on the problem. Eads explained the procedure that was used in his office:

After careful revisions by Col. Flad, the results obtained from time to time were submitted to me; and, finally, to guard against any possible error in the application of the principles upon which the investigations were made, or in the results arrived at, they were referred by me to the patient analysis and careful examination of Chancellor W. Chauvenet, LL.D., of the Washington University, formerly Professor of Mathematics in the U.S. Naval Academy at Annapolis. His certificate, affirming their correctness in every particular, will be found appended to this report. For the interest this gentleman has taken in the enterprise, for the care bestowed in examining and verifying the scientific data required for the work, and for many valuable suggestions and simplifications in the investigation, I feel under many obligations.

The title, degree, and affiliations of William Chauvenet, who was serving as consulting engineer to the project, were given, of course, to establish his authority and integrity, just as his certificate was to attest further to the correctness of Eads’s report. In virtually all large engineering projects there is one or more consulting engineers of vast experience and irreproachable authority, who provide either the basis for carrying out the details of the design or the imprimatur that some less prestigious engineer’s design is sound. The profession of engineering, like all professions, rests upon the exercise of sound judgment, and the interaction of engineers of varying degrees of experience must involve a delicate balance between recognizing and accepting something as correct, on the one hand, and recognizing that it might not be done in exactly the same way by another engineer—including the one doing the checking.

Engineers are also human, of course; sometimes they cannot entertain the idea that a competing design may be an equally correct, if different, solution to a problem. An earlier consultant to Eads, Jacob H. Linville, was an undisputed authority on railroad bridges. Having become the engineer for bridges and buildings for the Pennsylvannia Railroad in 1863, he had by 1864 completed the first long-span (320-foot) truss across the Ohio River, at Steubenville, on the West Virginia border. When Eads sent him the preliminary drawings for his own long-span arch bridge, Linville wrote back disapprovingly of the design: “I cannot consent to imperil my reputation by appearing to encourage or approve of its adoption.” He further wrote, “I deem it entirely unsafe and impracticable, as well as in fault in the qualities of durability.” Linville was perhaps more concerned with his own reputation as a proponent of more conventional trusses than with the safety of Eads’s design, and he was perhaps a bit disingenuous in condemning what he may not have fully understood. Not surprisingly, Linville suggested for St. Louis a truss bridge, one that could be assembled on pontoons, floated into place, and then raised into position by hydraulic jacks, the way Stephenson’s Britannia tubes had been, thereby obviating the objection to scaffolding obstructing the river during construction.

Eventually, however, with the opposition of Linville, Boomer, and the Convention of Engineers assembled to discredit Eads a thing of the past, he was able to proceed with the plans endorsed by Chauvenet and the board of directors. First the bridge’s piers had to be built up from the rock below the river bottom, for Eads believed that no other foundation would survive the scour of the Mississippi. Indeed, the need to sink the piers so deep gave Eads additional incentive to construct the smallest possible number of them in the river, and thus he had had to specify the longest practicable spans. This kind of trade-off is common in large bridge design and often has an enormous effect on the total cost of the bridge. However, later in 1868, before any final decisions had been made on how to sink the piers, Eads became ill with a terrible cough and, under a doctor’s orders to seek complete rest, tendered his resignation to the bridge company. But it was not accepted, and so work on the bridge, which had actually begun as early as August 1867 with the construction of the western abutment, was halted when Eads left for a restful trip to Europe.

Eads’s proposal for a bridge across the Mississippi River between St. Louis, on the left, and Illinois Town (photo credit 2.8)

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After six months, Eads came back briefly to New York in order to conduct some financial negotiations, then returned to Europe, where he discussed plans for his bridge with British and French engineers and visited construction sites. It was on this trip that Eads became acquainted with the relatively new technique of using a plenum pneumatic, or pneumatic caisson, for sinking foundations underwater, and he inspected at Vichy a bridge-construction site employing the procedure. The customary method, which Eads had had in mind initially, was to erect a cofferdam enclosing an area from which the water could be pumped out and the riverbed excavated to bedrock. Among the drawbacks to the cofferdam, however, was that it was open to the air, and thus exposed to the elements and subject to flooding. The new caisson method employed what was essentially a gigantic inverted box into which compressed air was pumped to keep the water out while the work went on inside. As the river bottom was excavated, Eads planned to pile heavy stones atop the caisson, thus erecting the pier at the same time that its weight pushed the caisson into the riverbed. The scheme appealed to Eads’s experience with submarine salvaging, being not unlike a gigantic diving bell or inverted and weighted barrel, and the sand pump he had devised for salvage work would also provide an efficient means of getting the excavated debris out of the caisson.

Thus, though the pneumatic-caisson method had been used for almost fifteen years to sink over forty piers in Europe, in America Eads was going to improve upon the concept and extend it to greater depths than ever before. The first caisson was launched from its own construction site, floated into position, and sunk in October 1869. Work inside the chamber was to continue smoothly day and night for five months, through the winter. As the exotic construction progressed, “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.” One retrospective description captured the experience of descending into the caisson:

For a while one felt perfectly comfortable in this underworld—a world such as no mythology and no superstition ever dreamed of. The transition, indeed, became apparent by pain in the ears, bleeding at the nose, or a feeling of suffocation; but these inconveniences and seeming dangers, inevitable upon such a visit to hell, were insignificant in comparison with the interest which it offered. It was undertaken by hundreds and hundreds of visitors, including many ladies, and none returned from that depth without carrying along with them one of the most remarkable reminiscences of their whole life. Shrouded in a mantle of vapor, labored the workmen there loosening the sand; dim flickered the flames of the lamps, and the air had such a strange density and moisture that one wandered about almost as if he were in a dream. For a short time all this was extremely interesting and delightful, but it was not long before the wish to escape again from this strange situation gained the upper hand over the charm which it exercised. Gladly did the visitor, after a quarter of an hour, re-enter the air-lock, with an unfeigned feeling of relief, to watch the air beginning to escape from this chamber. At once the door behind him leading from the caisson closed by the denser air, and fastened as firmly as if there was a mountain behind it. The compressed element escaped whistling from the air-lock; the air within was more and more equalized with the air without; a few minutes, and they were of equal density; then the door, no longer pressed against its frame by the dense atmosphere, opened to the winding stairs, and the visitor came forth taking a long breath, and, to use one of Schiller’s words, once more “greets the heavenly light,” which shone from far above down the shaft.

A caisson being sunk for the St. Louis Bridge (photo credit 2.9)

When the caisson had penetrated sixty-six feet, a telegraph terminal was installed inside it, “where all things hideous are,” enabling workmen there to communicate at all times with “those that breathe in the rosy light.” Eads used this telegraph as a promotional device to send greetings to bridge directors in New York, and visitors in the caisson sent messages to friends in the “outer air.” Such antics and poetic rantings demonstrate how casually the caisson was treated, and no doubt many of the visitors had a good laugh when a flask of brandy one of them had taken down into the depths, and there drunk from, exploded violently when they returned to the outer air. This, however, was but an amusing precursor of more serious events to come.

When the caisson reached a depth of seventy feet, the workmen began to experience some difficulty climbing the stairs to the surface. As the caisson was sunk deeper, men suffered increasing attacks of cramps and paralysis, which were thought to be due to insufficient clothing or poor nutrition. In March 1870, when the caisson had reached ninety-three feet, the air pressure inside it was about four times what it was in the open air, and workmen began dying upon emerging from the caisson, or after being hospitalized for an ailment that came then to be called “caisson disease” but today is known as “the bends.” Eads asked his family physician, Dr. Alphonse Jaminet, to look after the workmen, but Jaminet himself became paralyzed one day, having spent time down in the caisson and come up after only a few minutes in the air lock.

Perhaps somewhat to his own surprise, Jaminet recovered, and began to conduct research into these mysterious attacks. He shortly concluded that the major cause was too-rapid decompression in the face of a drastic difference in air pressure between the submerged caisson and the outer air above. Thereupon he placed restrictions on the amount of time the men could work inside the caisson, and on the speed with which the pressure in the air lock could be reduced. The west pier of the bridge, having to go to a depth of only eighty-six feet, was sunk with fewer incidents. Fatalities would also occur in sinking the caissons used in the piers for the Brooklyn Bridge, however, and Andrew H. Smith, a former army doctor and specialist at the Manhattan Eye and Ear Hospital, would be engaged as surgeon to the New York Bridge Company. Smith, like Jaminet, would eventually recognize too-rapid decompression as a prime contributor to the problems being experienced in the deep caissons.

In time, the physiological condition of the bends began to be understood and guarded against, but other aspects of work on large construction also imperiled the health and safety of workers and engineers alike. A bridge from New York to Brooklyn was John Roebling’s dream, but while he was involved in surveying to fix the location of the Brooklyn tower, in final preparation for beginning work on the pier, his toes were crushed when a ferryboat bumped into some piles of the slip on which he was standing. The symbolic significance and irony of the accident were probably not lost on the senior Roebling, who had had to fight for years the opposition of the ferryboat interests. He soon developed lockjaw, or tetanus, of which he died on July 22, 1869, a little more than three weeks after the accident.

John Roebling’s bridge did not die with him, of course, and it was under construction contemporaneously with that of Eads. The chief engineer was Roebling’s son Washington, who was born in 1837 and graduated from Rensselaer Institute in the Class of 1857. He gained practical experience in the family’s wire-rope mill, and in assisting his father in building the suspension bridge across the Allegheny at Pittsburgh, just before the Civil War. It had been said that the elder Roebling was upset when Washington enlisted in the Union Army, first in the New Jersey militia and later in a more active New York artillery regiment, for which he would build bridges and ascend in balloons to observe enemy movements. He was to become a veteran of such battles as Second Bull Run, Antietam, Chancellorsville, and Gettysburg, and attained the rank of lieutenant colonel, by brevet, before resigning in 1865 to assist his father with the completion of the Cincinnati and Covington Bridge across the Ohio River, now known as the Roebling Bridge.

While Washington was still in the army, he had met Emily Warren, sister of his general, at an officers’ ball. She captured his heart at first sight, and the two were married early in 1865. At his father’s request, the young Roebling couple went to Europe to make a study of pneumatic caissons, in preparation for the construction of the Brooklyn Bridge. They also visited such then famous suspension bridges as Telford’s across the Menai Strait and the Clifton Suspension Bridge erected across the Avon Gorge, near Bristol, as a memorial to Isambard Kingdom Brunel. Roebling was critical of the towers of each, mostly on aesthetic grounds, and found the deck of the Menai bridge to be very light and subject to vibrations. On the Continent, he received a grand tour of the Krupp ironworks in Essen, Germany, where he was shown an eyebar that had been made up especially for the occasion of the American engineer’s visit. Such eyebars were essential links in tying the steel strands of wire that make up suspension-bridge cables into the anchorage.

Throughout his travels, Washington Roebling wrote of what he was learning to his father, who was back in Trenton thinking about the great East River bridge and how it would be designed and constructed. The clear necessity of deep foundations for the towers, in particular, was of prime concern, and Washington’s information about caissons, which he spelled “cassoons,” was invaluable. Colonel Roebling, as he came to be known, also visited St. Louis, early in 1870; he and Captain Eads, who had become so designated in recognition of his exploits on the river, discussed caisson design. Subsequently, the roughly contemporaneous design of caissons to establish foundations for the St. Louis and Brooklyn bridges resulted in some conflicting claims, and in 1871 Eads sued Roebling for patent infringement. The rivalry led to a series of letters in the English trade journal Engineering, to which Eads first wrote in April 1873 to “correct some statements” made by Roebling in a pamphlet on pneumatic-tower foundations that he had recently published.

The crux of the matter concerned the location of the air lock, which Eads had put within the caisson’s chamber, thus making ingress and egress relatively convenient and obviating the need to pressurize the vertical access shaft, or even to make it airtight. What irritated Eads was Roebling’s statement that the idea was not new with Eads but had been used earlier in Europe, although admitting that “the first practical application … on a really large scale in this country” was in the St. Louis Bridge. Eads contended that Roebling had neglected to distinguish between iron caissons and those upon which masonry was piled, and that he had thus not given sufficient credit to the American innovation. Eads’s second letter to Engineering on the subject included drawings of Roebling’s Brooklyn caisson, which had the air lock outside the air chamber, and his New York caisson, launched about a year later, in May 1871, which had its air lock inside the air chamber and was clearly similar to Eads’s design. Eads explained his interest in carrying on about the matter, while incidentally getting in some digs against Colonel Roebling and providing some insight into the nature of what constituted engineering practice, then as now:

I trust I shall not be understood as finding fault with Colonel Roebling for copying my plans in his New York caisson. On the contrary, I hold it to be the duty of an engineer to use the surest and most economic methods which are known in accomplishing his work, and, if possible, to improve upon those methods. Nor is the lack of inventive talent, whereby it is frequently possible to improve on the plans of others, or to devise new ones, at all necessary to constitute an able engineer, or to insure professional success. It is of much greater importance that the engineer, on whom rests the responsibility of a work, should be competent to select the best devices proposed by his assistants, or used by others, than to be able to invent novel ones himself. The obligation to adopt the best is, however, not incompatible with a generous regard for the rights or merits of others, and his professional reputation will never suffer by giving such credit to them as may be justly due.

The exchange between Eads and Roebling may have been especially emotional because of the bad experiences both men had had personally, and because of their workmen’s suffering from the bends and other complications in the pressurized caissons. Late in 1870, a fire had broken out in the Brooklyn caisson, and Roebling worked himself to near-exhaustion directing operations to extinguish it. Spending so much time in the compressed and smoke-filled air caused him to suffer an attack of the bends and remain paralyzed for some hours. He recovered, only to suffer a much more serious attack in the New York caisson in 1872, when he appeared to be close to death. He recovered again, however, or appeared to, and went back to active work on the bridge. But by the end of the year, he was in extreme pain and frequently sick to his stomach, and he and Emily went to Europe for his health. He never did fully regain his strength, and was to spend three years in Trenton while the bridge towers were completed. Eventually, he became bedridden, in a room that overlooked the bridge under construction, with Emily effectively serving as assistant engineer and intermediary between the incapacitated chief engineer and his lieutenants on the construction site.

Though an engineer like Eads or Roebling dominates the story of a given bridge at a given time, that engineer is typically not only one among many working on similar problems contemporaneously, but also constantly dependent upon the assistant engineers responsible for the various parts of each larger project. Among the young men Washington Roebling had hired as assistants shortly after his father’s death was Francis Collingwood, Jr., who in 1855 had graduated first in his class from Rensselaer Institute, where the younger Roebling had met him. Collingwood had worked as a city engineer in his hometown of Elmira, New York, and in the family jewelry business before being asked by Roebling to help the self-taught engineer William Paine on the Brooklyn caisson. Though Collingwood agreed only to a short engagement, he became so involved that he was among those engineers believed to have been capable of taking charge of the work in the event of Roebling’s death, and remained associated with the work until its completion in 1883. Collingwood’s distinguished career on the Brooklyn Bridge project, and later as a consulting engineer, is remembered today in the American Society of Civil Engineers’ Collingwood Prize, which he instituted and endowed in 1894 to recognize young engineers who publish technical papers of exceptional practical merit. The subjects of prize-winning papers can range from the foundation of piers to the capacity of the superstructure they support. Whether engineers write such papers or not, the problems they deal with, as Eads and his colleagues knew, must be addressed in designing and building the artifacts.

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As papers alone do not make a design, so piers alone, difficult as they may be to construct, do not make a bridge. Eads wanted the superstructure between and over the piers to be as solid as the masonry it would bear against, and in his report he wrote as follows about the strength of the bridge under the heaviest load that he could conceive its ever having to carry: “The arches have been designed with sufficient strength to sustain the greatest number of people that can stand together upon the carriage way and foot paths from end to end of the Bridge, and at the same time have each railway track below covered from end to end with locomotives.”

In addition to all the people and locomotives it might have to carry, Eads’s bridge would have to carry its own weight, of course. For many a bridge, in Eads’s time as well as before and since, the weight of the structure itself can be so many times greater than what could physically be crowded onto it that a considerable proportion of its strength must go toward just holding itself up. The weight of a structure is also a principal determinant of its cost, and so there are clear advantages to using material that is strong relative to its weight. Before the 1860s, steel was not generally available in sufficiently large amounts or pieces to be incorporated in bridge structures, but Eads believed that the most economical arch would be made up of cast-steel tubular segments. He thus specified steel for the major structural elements, making his bridge the first to incorporate so much of the high-strength material.

The Keystone Bridge Company of Pittsburgh was given the contract to build the superstructure. Keystone grew out of what Andrew Carnegie called the first iron-bridge company, the firm of Piper & Schiffler, which he organized in 1863 with the help of the engineer Jacob Linville, the “hustling, active mechanic” John L. Piper, and “a sure and steady” Mr. Schiffler, whose first name Carnegie seemed to have forgotten in writing his autobiography. In 1865, the Piper & Schiffler firm was absorbed into Keystone, a name Carnegie was “proud of having thought of as being most appropriate for a bridge-building concern in the State of Pennsylvannia, the Keystone State.” Among the first major contracts of what came to be Keystone was the enormous 320-foot-span truss bridge over the Ohio at Steubenville. By the time Eads approached them, the very successful company had an established reputation but a “bad credit” rating, according to Bradstreet’s, because they never borrowed any money.

Andrew Carnegie and James Eads were perhaps more alike than either of them might have wanted to admit. Like Eads, Carnegie finished his formal education at age thirteen, when his family sailed from Scotland to America to seek better opportunities. They settled in Pittsburgh, where young Andrew began working as a messenger boy. He had to stay on in the office every other night, thus getting home as late as eleven o’clock, and that “did not leave much time for self-improvement, nor did the wants of the family leave any money to spend on books.” It so happened, however, that a Colonel James Anderson “announced that he would open his library of four hundred volumes to boys, so that any young man could take out, each Saturday afternoon, a book which could be exchanged for another on the succeeding Saturday.” Andrew found that Colonel Anderson’s largess extended only to “working boys,” however, “and the question arose whether messenger boys, clerks, and others, who did not work with their hands, were entitled to books.” Not to be deterred, Andrew wrote a letter to the Pittsburgh Dispatch, arguing for a more inclusive policy, and his persistence paid off: he was allowed to check out a book a week. The memory of this experience no doubt prompted an older and more affluent Carnegie to give so many libraries to communities.

As youths, Carnegie and Eads read in different subjects, the former reveling in history and essays, the latter in science and mechanics. Yet great engineering projects tend to bring such disparate traditions and personalities together, and by the time the two men met over the plans for the St. Louis Bridge, they were equally headstrong, albeit each in his different sphere of endeavor. Carnegie remembered Eads as an “unusual character,” whom he characterized as “an original genius minus scientific knowledge to guide his erratic ideas of things mechanical,” but Eads’s own reports and achievements belie this assessment. Carnegie’s point of view was no doubt influenced by Linville, who advocated trusses, like the one at Steubenville, over arches for large bridges. Linville told Carnegie that if the St. Louis bridge were built on Eads’s plans, it would “not stand up; it will not carry its own weight.” Keystone could not sell a truss bridge to the customer Eads, however, for, according to Carnegie, he “was seemingly one of those who wished to have everything done upon his own original plans. That a thing had been done in one way before was sufficient to cause its rejection.” Eads’s response to such criticism was reflected in his report, where he wrote, “Must we admit that because a thing never has been done, it never can be, when our knowledge and judgment assure us that it is entirely practicable?”

Eads wanted a steel arch, not unlike the one in Koblenz, and Keystone did agree to construct it for him, but this was not to be easy. After approval of the plans, the next step lay in raising the money. This obstacle was overcome thanks to Carnegie’s “first large financial transaction,” the sale of some bridge mortgage bonds to Junius S. Morgan, the American financier in London and father of J. Pierpont Morgan. Getting the steel parts fabricated and assembled into the bridge was another matter. John Piper, who began addressing Eads not just as “Captain” but also as “Colonel,” came to refer to him in succession as “Mr. Eads,” “Jim Eads,” and occasionally “Damn Jim.” When Eads insisted on steel over iron parts, it took considerable time and money to get them made to meet the specifications. The joke that had been current when the bridge was still a proposal could thus continue to be told:

First gentleman: “How much would the bridge cost?”
Second gentleman: “Seven million dollars!”
First gentleman: “How long will it take?”
Second gentleman: “Seven million years!”

Once the steel parts were made and shipped to St. Louis, they were erected without interfering with traffic on the river. The method employed had been suggested over a half-century earlier by Telford as a means of constructing a five-hundred-foot cast-iron arch across the Menai Strait without the use of any scaffolding in the water, and in St. Louis it was implemented by extending the halves of each arch—part by part—equally on either side of the central piers, supporting the heavy mass by guy wires that passed over temporary towers erected atop the piers—until the arch was completed and could support itself. Eads had at one point urged the use of catenary cables, slung over towers much like a suspension bridge, to support the partial arch, but the steadily changing weight of the arch as it progressed out from each tower would have called for constant readjustment of the curve. Early in 1871, Linville proposed to Walter Katté, engineer in charge of Keystone’s western office, in St. Louis, that direct guys to the towers and backstays be used, along with Henry Flad’s scheme of using hydraulic rams to adjust cable tensions, thus effectively employing the cantilever principle to support balanced back-to-back arch sections until the completed arches could support themselves. Original estimates were that the arches could be completed in a few months, but delays in receiving parts slowed the work considerably. Since financial assumptions had been based on projected revenue once the bridge was completed, it was imperative that steady progress be made toward that end. Incentives were offered to Keystone to close the arches by January 1, 1874, and to have the bridge ready for traffic by March.

The St. Louis Bridge under construction, showing the cantilever principle employed (photo credit 2.10)

By the end of the summer of 1873, the halves of the arches were approaching each other, but the critical operation of putting the last piece of steel in place was thwarted by the exceedingly high seasonal temperatures, which had so expanded the metal that the gap was too small for what might be called the steel keystone. Eads was in Europe at the time, recuperating from a condition characterized by chronic coughing and hemorrhaging lungs, and the task fell mainly to Henry Flad and a young engineer named Theodore Cooper, who earlier had been responsible for making sure that the steel mills were producing the proper material for the bridge parts. When the late-summer heat showed no signs of letting up, a wooden trough was constructed along the entire length of the arch, so that ice might be packed in and cool the steel enough to contract it—and thus open the gap wide enough for the last piece to be inserted. This scheme did not succeed, however, and it was necessary to resort to an alternative plan that had been devised by Eads.

Earlier in the year, he had applied for a patent involving the erection of arches that incorporated a screw mechanism capable of raising the completed arch a few inches, so that the supporting cables would be slackened and could be removed. By cutting the ends off the too-long arch ribs, threading them, and inserting the screw mechanism into the sprung arch, it was possible to close the arch on September 17. After that, work went relatively smoothly and quickly, and in January all the cables were removed and the arches became self-supporting. The Keystone Bridge Company announced that the bridge was to be available for pedestrian use in late April, but then Carnegie reconsidered allowing any traffic on the bridge until his company had been paid. It was another month before the upper roadway was opened to pedestrians and fifteen thousand people paid a nickel apiece for the privilege of being among the first to walk across the Mississippi at St. Louis. By July 2, the rails had been completed on the lower deck, and fourteen heavy locomotives, in two sets of seven, were driven back and forth for five hours, first on both sets of tracks and then in one long line. Such a procedure, during which engineers monitor the structure’s behavior, constituted what is known as a proof test.

The formal opening of the bridge, scheduled for July 4, 1874, was to be a gala affair. Invitations announced that President Ulysses S. Grant would attend, but he canceled at the last moment—too late to have his picture and references to him deleted from memorabilia of the event. The citizenry might have been more disappointed if James Eads had not attended, however. His portrait alone graced the invitation; it dominated a broadside issued for the occasion; and a fifty-foot-high portrait of him hung from the bridge, with the notation that the Mississippi had been discovered by Marquette in 1673 and spanned by Eads in 1874. A parade almost fifteen miles long, with a great line of carriages leading a procession of representatives of various trades and occupations, crossed and recrossed the bridge.

A contemporary photograph taken after the arches of the St. Louis Bridge became self-supporting (photo credit 2.11)

Eads began his speech at the opening ceremonies by admitting his belief that “the love of praise,” whether “a frailty or a virtue,” was “common to all men,” that he was not exempt from its fascination, and that it served as a “laudable stimulus to effort.” Love of praise was, furthermore, “the grand motor which actuates the mind of man to attempt the accomplishment of worthy deeds,” and the building of what that day was the greatest bridge in America was certainly a worthy deed. Eads, however, like many a chief engineer at the dedication of a great work, recognized that he had not built the bridge himself, and he spoke explicitly of the help he had received:

Yon graceful forms of stone and steel, which prompt this wonderful display, stand forth, not as the result of one man’s talents, but as the crystallized thought of many, aye, very many minds, and as the enduring evidence of the toil of very many hands; therefore I would forfeit my self-respect and be unworthy of these pleasing evidences of your good will, if on this or any other occasion, I should appropriate to myself more than an humble share of the great compliment you are paying to those who created the bridge.

Eads spoke of himself that day as the representative of a “community of earnest men, whose combined labor, brains and wealth, have built up this monument of usefulness for their fellow-men.” He mentioned few facts and figures about the bridge, about which already so much had been written. Rather, he spoke of the design and construction process that assured him and his fellow engineers that the bridge was safe:

Everything which prudence, judgment and the present state of science could suggest to me and my assistants, has been carefully observed, in its design and construction. Every computation involving its safety has been made by different individuals thoroughly competent to make them, and they have been carefully revised time and again, and verified and reexamined, until the possibility of error nowhere exists.… When the first arch was closed, Mr. J. S. Morgan, of London, whose firm has supplied so many millions for this work, and whose confidence in it has contributed so much to its success, wrote me, hoping that the closing of the arch had made me as happy as it had him. I replied that the only happiness I felt was in the relief that it afforded my friends, for I knew it would be all right.…

Eads also confessed that he had felt no great relief when the piers reached bedrock, or when the first heavy locomotives were driven over the finished bridge, for he “had felt no anxiety on the subject.” He felt “justified in declaring that the bridge will exist just as long as it continues to be useful to the people who come after us, even if its years should number those of the pyramids.” He explained with some technical detail how the sun and temperature caused various parts of the bridge to be relieved of strain at different times of the year, so that any piece of steel could be “easily taken out and examined, and replaced or renewed, without interrupting the traffic of the bridge.”

Among those individuals Eads singled out in connection with making the dream of the bridge a reality, the financier Morgan was the one most prominently mentioned. Several bridge-company directors were also acknowledged by name, complete with titles, for their “unswerving confidence and kindness.” The longest list of names, however, comprised those of the assistant engineers, their assistants, and others who provided “indispensable services.” Eads’s listing of these by surname only was no doubt a sign of his familiarity with them: “Flad, Roberts, Pfeiffer, Dwelle, Cooper, Devon, Gayler, Schultz, Wieser, Smith, McComus, Wuerpel, Klemm, and a host of others, earnest, faithful and accomplished.” He also acknowledged James Andrews, master mason; Walter Katté and his foreman, McMahon, “the skillful engineer” who swung the bridge’s steel arches into place; William S. Nelson, responsible for the caissons beneath the piers; and Charles Shaler Smith, for the Illinois approach to the bridge. There was no mention of Andrew Carnegie. Eads closed by observing what has been heard at many a bridge dedication ceremony, that “a great work is rarely erected without the sacrifice of human life,” and he remembered those who had died during the construction project, especially those who had died in the caisson work.

That evening, there was to be a spectacular display of fireworks set off from the bridge, and hotels and steamboats had long advertised their verandas and decks as the best viewing locations. The pyrotechnic artist W. W. Judy was pictured along with President Grant and engineer Eads on a memorial broadside, but the show was a great disappointment. One of the “grand Temple pieces” was to be “of the bridge itself surmounted by allegorical figures representing Missouri and Illinois, clasping hands.” Another was to be of “Eads in the Temple of Honor, flanked by a locomotive and a steamboat, being crowned by Genius.” The illuminated “Phantom Train,” however, which was to traverse the entire bridge as a climax to the day’s events, was nowhere to be seen. The organizing committee had apparently economized in its contract with Judy, who came to be called “Judy Iscariot.” Many of the actual trains expected to cross the new bridge were also in fact phantoms, for it would be almost a year before the first regular passenger train contributed to the revenue. This, of course, was contrary to estimates made when the bridge was being financed, and soon the company went bankrupt.

The official name of the bridge, as it appeared on invitations, was the “Illinois and St. Louis Bridge,” but Chicago newspapers delighted in calling it the “Chicago and St. Louis Bridge.” The definitive history of the engineering enterprise, published in 1881, called it the “St. Louis Bridge,” but then as now it was known to all as the “Eads Bridge,” making it one of the few major structures in the world named after their engineers. Ironically, in 1924, the Eads Bridge was identified as among the works of the U.S. Army Corps of Engineers, “conducted principally, or in most important executive or advisory capacity,” by West Point graduates. This was, of course, a gross misattribution, and it did not escape the notice of Arthur E. Morgan, the fractious first chairman of the Tennessee Valley Authority. Morgan was a self-educated engineer whose work in drainage and flood protection gave him a special perspective on the work of the Corps. From 1920 to 1936, he was president of Antioch College, where he fostered the school’s work-study plan, and he wrote books on topics ranging from religion and science to a critical history of the Army Corps of Engineers.

6

The Corps of Engineers had little control over the Eads Bridge, of course, for it was planned and built before there was a law requiring prior approval by the secretary of war and the chief of engineers for bridges over navigable waters. Not that the secretary and the Corps did not try to influence the bridge. As the arches of Eads’s bridge were closing over the river, the operators of Mississippi steamboats had complained to William Belknap, the easily bribed secretary of war who would be impeached in 1876, that the bridge would interfere with their tall stacks, which, “flamboyant in their gaudy paint and gilded fretwork, were the boatmen’s pride, cherished trademarks of the western steamers.” The Corps of Engineers was ordered by Belknap to look into the matter of the bridge as an obstacle to navigation, and its report recommended that one of two actions be taken: (1) a deep-water canal be constructed on the Illinois side to bypass the bridge, or (2) the bridge be dismantled. Furthermore, all future bridges across the Mississippi at St. Louis were to be of the truss type. Eads appealed to President Grant, whose birthplace near Point Pleasant, Ohio, was less than fifty miles up the Ohio River from Eads’s Lawrenceburg, and Grant suggested that Belknap “drop the case.” Though the Corps persisted, Eads prevailed.

Eads’s nemesis in the Corps of Engineers was General Andrew Atkinson Humphreys, who had concurred in the recommendations of the Corps’s board. Humphreys and his associate, General Henry Larcom Abbot, had in 1861 first published their Report on the Physics and Hydraulics of the Mississippi River; it had since become the “bible” of the Corps, and its authors the Corps’s authorities on questions of river improvements. To challenge Humphreys and Abbot was to invite trouble, as Eads was to learn. A year before his bridge was completed, a convention of congressmen, governors, and interested citizens was convened in St. Louis to discuss the Mississippi River, whose mouth was constantly silting up and hindering shipping. The Corps of Engineers, which had been working for forty years to keep the channel open, were now proposing a canal from New Orleans to the sea. Eads joined the delegates on an excursion to New Orleans and the delta, and he proposed a system of jetties as a quicker, more economical, and more effective solution. It was within two months of Eads’s proposal that his bridge at St. Louis had become the subject of retrospective scrutiny by the Corps of Engineers.

Whereas the action backed by Humphreys and Abbot was to build a canal from New Orleans to the Gulf of Mexico, Eads proposed extending parallel jetties from one pass of the river into the Gulf. He recommended first constructing long parallel screens of willow branches, held in place by piles under the water, in order to slow the current through the obstacles enough so that the sand it carried would be deposited. Properly arranged, this barrier would cause the water to flow more quickly in the unobstructed channel, and the increased velocity would itself in time scour out a deeper channel.

A Board of Army Engineers was instructed to report on the canal scheme, which it endorsed, and on the idea of jetties, which it condemned. Only General John Gross Barnard, president of the board, dissented. He considered his fellow board members to be engineers in name only, engineers “in a narrow executive capacity,” but lacking in “the wide induction of experience [and] the wide observation of travel to see and judge other engineering works—[and in] the indispensable familiarity with what engineering is in its practical developments all over the world which alone can give any insight into an opinion on a great engineering question.” Furthermore, and perhaps most culpably, they did not even “know their own deficiency.” There were certainly extra-engineering reasons behind the opposition to Eads, however, no doubt fueled by his lengthy review, occupying twenty-five pages of small type in his collected addresses and papers, of the Humphreys and Abbot “bible.” In this review, which first appeared at the height of the canal-jetty debate—in 1878, in Van Nostrand’s Engineering Magazine—Eads stated that Humphreys and Abbot’s book, then recently reissued, “contains certain grave errors,” which Eads proceeded to expose, “touching the navigation of the river and the reclamation of its alluvial basin.”

The official Corps of Engineers estimate was that a canal would cost $13 million whereas Eads’s scheme would run to twice that amount, and his jetties would constantly have to be extended into the Gulf of Mexico to maintain channel depth. Eads countered with a proposal to secure a 350-foot-wide channel at a depth of twenty-eight feet in half the time it would take to construct a canal, and with payment from the government commencing only after he had achieved a certain measure of success; the total bill was to have been about $10 million. This presented a classic choice between a government project and private enterprise. Not surprisingly, the Corps continued to oppose Eads’s proposal, and a protracted legislative battle ensued. Eads revised his proposal, promising a deeper channel through the preferred Southwest Pass of the river through the delta, at a lower cost of $8 million. The final legislation gave approval to Eads’s latest financial offer, but authorized jetties only at the smaller South Pass.

In an address at a banquet in honor of the passage of the 1875 Jetty Act to Improve the Mouth of the Mississippi, Eads spoke eloquently of his conviction that his system would work:

If the profession of an engineer were not based upon exact science, I might tremble for the result in view of the immensity of the interests which are dependent upon my success. But every atom that moves onward in the river, from the moment it leaves its home amid crystal springs or mountain snows, throughout the 1,500 leagues of its devious pathway, until it is finally lost in the vast waters of the Gulf, is controlled by laws as fixed and certain as those which direct the majestic march of the heavenly spheres. Every phenomenon and apparent eccentricity of the river, its scouring and depositing action, its caving banks, the formation of the bars at its mouth, the effect of the waves and tides of the sea upon its currents and deposits, are controlled by laws as immutable as the Creator, and the engineer needs only to be assured that he does not ignore the existence of any of these laws, to feel positively certain of the result he aims at.

I therefore undertake the work with a faith based upon the ever constant ordinances of God himself; and so certain as He will spare my life and faculties for two years more, I will give to the Mississippi river, through His grace, and by the application of His laws, a deep, open, safe, and permanent outlet to the sea.

Eads was expressing the same confidence in the engineering method with regard to opening a deep channel at the river’s mouth as he did in his bridge, of course, and his success was virtually guaranteed, because he knew the laws governing the fluidity of the river even better than he had come to know those governing the solidity of steel. Constructing the jetties took Eads’s own capital, however, and he had to fight continued battles with the Corps of Engineers to get paid for work done according to specifications. The jetty system, called “the most difficult piece of engineering in river hydraulics,” was ultimately a tremendous success. After four years of work, in 1879, the South Pass channel reached a depth of thirty feet, a depth greater than required even in busy New York Harbor, and it was said that “the savings on transportation of one year’s cotton crop alone was equivalent to the cost of the entire jetty project.”

With the establishment of the South Pass channel, Eads had thus added another monumental engineering achievement to his life’s work. But, although he was not yet sixty years old, his health had suffered from the many extended periods of time he had worked underwater, first in his diving bell but especially in the compressed air of the caissons at St. Louis, which would remain the deepest such atmosphere at which workers toiled for almost a century of bridge building. Nevertheless, Eads was not the sort of person to retire, and one of the major engineering issues of the day continued to interest, if not obsess him.

A common thread to all of Eads’s work related to the efficient transportation of goods, upon which he believed national prosperity depended. In a speech at the dedication of the Grand Hall of the Merchants’ Exchange in St. Louis, in 1875, he articulated his fervor for the subject:

The key-note of our national prosperity is sounded in the simple words, “Cheap Transportation.” They should be stamped upon the stripes of our national banner and thrown to the breeze from every farm-house, mill, and factory throughout the commonwealth. Schoolboys should be taught that the superior facilities for cheap transportation secured to Phoenicia, Athens, Venice, Genoa, the Florentine Republic and Holland, the commerce of the world. Each retained it until its rival became a cheaper carrier; and it is a notable fact that art, refinement, literature, history and eloquence attained in each State their highest development during its commercial sway.

Great civil-engineering projects to facilitate transportation and communication—including roads, harbors, canals, and bridges—were essential to the prosperity to which Eads was referring, of course. He was echoing the growing spirit of the nineteenth century, which recognized the importance of the engineer in “directing the great sources of power in nature for the use and convenience of man,” as Thomas Tredgold had defined civil engineering a half-century earlier for the purposes of obtaining a Royal Charter for the Institution of Civil Engineers. This formalization of the profession was the natural culmination of the realization that the work of engineers had in fact “changed the aspect and state of affairs in the whole world.” But engineers like Eads did not think the job was yet completed, for there remained many obstacles to cheap transportation, especially between the East and West Coasts.

Increasing international commerce in the latter part of the nineteenth century created worldwide interest in a canal across Central America, to reduce the time and risk that ships took in transporting people and cargo between the Atlantic and Pacific Oceans. By 1855, a fifty-mile railroad across the Isthmus of Panama—the first transcontinental railroad—presented an alternative to the thousands of sea miles (and added perils) it took to get around the southernmost part of South America. Of course, unloading ship cargo onto railroad trains and reloading it onto ships at the other terminus was as costly as ferrying rail freight across rivers without bridges. By the late 1870s, a private French company had been formed to explore options, and the prospect of an Isthmian canal, promoted by “Le Grand Français,” Count Ferdinand de Lesseps, who had been responsible for the Suez Canal, offered some promise amid great engineering controversy.

Needless to say, the problem of interoceanic communication and de Lesseps’s scheme attracted the attention of American interests generally and James Eads in particular. In an 1880 address before the House Select Committee on Inter-Oceanic Canals, Eads offered his opinion:

The question of the practicability of opening a tide-level waterway through the American isthmus is simply a question of money and of time. If sufficient money were supplied, and time enough were given, I have no doubt that, instead of the narrow and tortuous stream which Count de Lesseps proposes to locate at the bottom of an artificial canon [sic] to be cut through the Cordilleras at Panama, engineers could give to commerce a magnificent strait through whose broad and deep channel the tides of the Pacific would be felt on the shore of the Caribbean Sea, and through which the commerce of the next century might pass unvexed, from ocean to ocean.

The science of engineering teaches those who practice it how the forces of nature may be utilized for the benefit of mankind, and it is the duty of the engineer when charged with the responsibility of solving an important engineering problem, by which his fellow men are to be benefited, to consider carefully how the desired results can be most cheaply and most quickly secured. Therefore, it is his duty to consider every method for the accomplishment of the end in view which science and nature have placed within his power, and to select from the fullness of their stores such methods as the precise teachings of mathematics and a knowledge of the laws which control the forces of nature assure him will certainly accomplish the desired result in the least time and for the least money.

The method Eads had come up with was not a canal but a ship railway, in which fully laden vessels would be loaded onto great flatcars and pulled by teams of locomotives on multiple parallel tracks across the Isthmus of Tehuantepec. Such a trans-Mexican route would save ten thousand miles over the sea route via Cape Horn, and more than a thousand miles over the Panama Railroad route. Eads believed the ship railway could be completed long before de Lesseps’s canal, and at a lower cost, and the American engineer spent the remainder of his life promoting his novel scheme. Other American interests included a more conventional canal over a Nicaraguan route. The political and technical debate outlasted Eads: he died on March 8, 1887, in Nassau, in the Bahamas, where he was seeking support for his final, unrealized dream. No other engineer, no matter how young, could take it up with the vigor of Eads. Had he chosen to devote his more youthful energies to a trans-Mexican ship railway, we might not have the bridge that to this day memorializes him on his river. There would no doubt have been a bridge across the Mississippi at St. Louis before long, and certainly by the end of the century, but it would not have been Eads’s bridge. However, because his is the bridge that was built, it constituted a legacy from Eads and his assistant engineers, not only to the people who used and benefited from it, of course, but also, in its technical achievement, to the entire bridge-building fraternity, which everywhere in the last decades of the nineteenth century possessed the dreams, ambitions, and unbridled energies of youth.

James B. Eads shortly before his death, in a photograph by Emil Boehl (photo credit 2.12)