When the Rebellion came, it was soon evident that a strong fleet must be put upon Western rivers to assist our armies. Word came from the government to Captain Eads to report in Washington. His thorough knowledge of the "Father of Waters" and its tributaries, and his practical suggestions, secured an order to build seven gunboats, and soon after an order for the eighth was given.
In forty-eight hours after receiving this authority, his agents and assistants were at work; and suitable ship-timber was felled in half a dozen Western States for their hulls. Contracts were awarded to large engine and iron works in St. Louis, Pittsburgh, and Cincinnati; and within one hundred days, eight powerful ironclad gunboats, carrying over one hundred large cannon, and costing a million dollars, were achieving victories no less important for the Mississippi valley than those which Ericsson's famous "Cheese-box Monitor" afterwards won on the James River.
These eight gunboats, Commodore Foote ably employed in his brave attacks on Forts McHenry and Donaldson. They were the first ironclads the United States ever owned. Captain Eads covered the boats with iron: Commodore Foote covered them with glory.
Eads built not less than fourteen of these gunboats. During the war, the models were exhibited by request to the German and other governments. His next work was to throw across the mighty Mississippi River, nearly half a mile wide, at St. Louis, a monstrous steel bridge, supported by three arches, the spans of two being five hundred and two feet long, and the central one five hundred and twenty feet. The huge piles were ingeniously sunk in the treacherous sand, one hundred and thirty-six feet below the flood-level to the solid rock, through ninety feet of sand. This bridge and its approaches cost eighty millions of dollars, and is used by ten or twelve railroad companies. Above the tracks is a big street with carriage-roads, street-cars, and walks for foot-passengers.
The honor of building the finest bridge in the world would have satisfied most men, but not ambitious Captain Eads. He actually loved the noble river in which De Soto, its discoverer, was buried, and fully realized the vast, undeveloped resources of its rich valleys. Equally well he understood what a gigantic work in the past the river and its fifteen hundred sizable tributaries had accomplished in times of freshets, by depositing soil and sand north of the original Gulf of Mexico, forming an alluvial plain five hundred miles long, sixty miles wide, and of unknown depth, and having a delta extending out into the Gulf, sixty miles long, and as many miles wide, and probably a mile deep. And yet this heroic man, although jealously opposed for years by West Point engineers, having a sublime confidence in the laws of nature, and actuated by intense desire to benefit mankind, dared to stand on the immense sand-bars at the mouth of this defiant stream, and, making use of the jetty system, bid the river itself dig a wide, deep channel into the seas beyond, for the world's commerce.
Captain Eads, who had studied the improvements on the Danube, Maas, and other European rivers, observed that all rivers flow faster in their narrow channels, and carry along in the swift water, sand, gravel, and even stones. This familiar law he applied at the South Pass of the Mississippi River, where the waters, though deep above, escaped from the banks into the Gulf, and spread sediment far and wide.
The water on the sand-bars of the three principal passes varied from eight to thirteen feet in depth. Many vessels require twice the depth. Two piers, twelve hundred feet apart, were built from land's end, a mile into the sea. They were made from willows, timber, gravel, concrete, and stone. Mattresses, a hundred feet long, from twenty-five to fifty feet wide, and two feet thick, were constructed from small willows placed at right angles, and bound securely together. These were floated into position, and sunk with gravel, one mattress upon another, which the river soon filled with sand that firmly held them in their place. The top was finished with heavy concrete blocks, to resist the waves. These piers are called "jetties," and the swift collected waters have already carried over five million cubic yards of sand into the deep gulf, and made a ship-way over thirty feet deep. The five million dollars paid by the United States was little enough for so priceless a service.
In June, 1884, Captain Eads received the Albert medal of the British Society of Arts, the first American upon whom this honor has been conferred. Before his great enterprise of the Tehuantepec ship railroad had been completed, he died at Nassau, New Providence, Bahama Islands, March 8, 1887, after a brief illness, of pneumonia, at the age of sixty-seven.