And more of the large shells were falling, until there was an almost continuous roar of detonating high explosives. Unlike normal cannon that fired shells directly at a target, these mortars arched a giant missile high into the air, to plunge down almost vertically onto the target below. Battlements and walls that faced the enemy were no defense against this kind of attack.
But General Bagnell was not aware of this debacle. He, and all of his officers, had been blown to pieces by the third shell that had landed on the fort. He did not live to see either the destruction of his fort or the obliteration of the gun emplacements across the river by the fourth mortar ship. In thirty intense, destructive minutes, all of the defenses of the river at Tilbury had been destroyed. Even as the firing ceased, the first of the long line of ships nosed into sight around the bend in the river and moved, unharmed, toward London.
USS Atlas had been idling her engines to keep position in the river against the tidal current. When the mortar ships had ceased firing, her captain saw that the boat that had been shielded by the bulk of the Thunderer was now pulling away from her flank. Good. Admiral Farragut was transferring his flag to the Mississippi — and taking the Thames pilot with him. Everything was going as planned. As soon as the boat reached the ironclad, Captain Curtin ordered the engines slow ahead. Three blasts on her steam whistle signaled the rest of the waiting ships to follow her upstream. As they got under way, USS Mississippi surged forward, passing the slower cargo ship and taking her position in the lead. After the successful landings at Penzance, she had proceeded to the mouth of the Thames to join the attacking squadron. Now she raced ahead, guns loaded and ready, to seek out any other river defenses.
Beside Curtin on Atlas’s bridge, General Sherman looked at the smoking ruins of Tilbury Fort as they moved slowly by. “Utterly destroyed in less than half an hour,” he said. “I have never seen anything like it.”
Curtin nodded understandingly. “That is because you are a soldier and see war as something to be fought on land. But you must remember the success of General Grant’s mortar ships in the Mississippi at Vicksburg. No railway gun can match one of these sea-battery mortars for size — and no team of horses could ever move one. But put them into an iron ship and you can cross oceans with them. Just as they have done. But it took the genius of a nautical engineer to design and manufacture them as well.”
“I agree completely. Mr. Ericsson is an asset to our country — and most certainly will lead us to success in this war. Are you pleased with the ship you command, Captain? This is also his design.”
“Not pleased — ecstatic, if you will permit me to use a word with many connotations. I believe that Atlas is the most powerful ship that I have ever commanded. With twin engines and twin screws, she is in a class by herself. And like her namesake, she cannot quite carry the world on her shoulders — but she comes mighty close to it.”
The Thames curved in great loops as they made their way upriver. As they came into the Dartford reach, there was the flash of guns from the Mississippi ahead of them.
“That will be the arsenal at Woolwich,” Sherman said. “They have some batteries facing the river there, but nothing much to speak of. Tilbury Fort is the major defense of the Thames, and no hostile fleet was ever expected to get by her armaments or reduce her by siege.”
“Perhaps that was true of yesterday’s wars,” Curtin said. “But not today’s.”
Mississippi was already at the next bend in the river when they passed Woolwich. A few battered and burning gun emplacements on the shore were all that remained of her defenses.
The Thames here made a great swing around the Isle of Dogs, and when the river straightened again all of the commercial heart of London opened out before them. There were ships tied up at the docks on both shores, merchantmen from every corner of the empire. Fresh fruit was being unloaded at Limehouse — whence it got its name. Behind Atlas the line of black ships followed steadily — an invasion force that was piercing straight into the heart of London.
More firing sounded ahead as the American ironclad began trading fire with the batteries of the Tower of London. But here, as in Woolwich, the defenses were not substantial at all. One of the towers of the famous castle crumbled under the ship’s fire.
One by one Mississippi’s guns grew silent, their work done, as the shore defenses were battered into destruction. Her funnels were riddled with holes, her boats shot away, but other than that, the ironclad appeared unharmed. Smoke rolled up from her funnels as she gained way, moving ponderously toward the riverbank, letting Atlas proceed up the main channel.
The river was clear ahead. Sherman recognized it from the many photographs and maps that he had pored over. On the right was the road along the Embankment, with fine buildings behind it. Beyond the buildings were the Gothic towers of the Houses of Parliament, the main tower with its immense clock face visible far downriver. The hands pointed to noon. Sherman stepped out onto the wing and could hear the deep tolling of Big Ben sounding the hour. It was the beginning of the afternoon of the British Empire.
Atlas’s engines were silent as she drifted toward the Embankment, slower and slower. There were hansom cabs and drays on the road there, private carriages and pedestrians. They were fleeing now as the hulking black ship grated against the granite river wall.
Even before she touched, sailors had leaped over the lessening gap, seized the cables passed down to them, and made them fast to the stone bollards of the waterfront. The sudden rattle of rifle fire sounded; two of the sailors twisted and dropped. Bullets clanged against the metal of the bridge, shooting out one of the windows. A line of red-coated soldiers had advanced from Parliament Square. The front rank stopped to fire — just as the bow battery of Atlas fired a canister shell. Holes opened suddenly in the advancing ranks of redcoats. Then a dark shadow passed over Atlas as Mississippi slid by, her guns opening fire as soon as they could bear.
Captain Curtin was out on the wing of the bridge, ignoring the fire from the shore, issuing commands. The moment his ship was securely moored, he ordered the upper ramp to be extended. The outer door swung slowly aside and there was a mighty clanking as the steam pistons pushed the tons of metal out and down. The information that had been passed on by the Russian agents proved to be correct. At this time of day, on this date, at this particular place, where the tidal river rose and fell by a dozen feet, the ramp was exactly two feet above the granite of the river wall. It clanked down into place; metal screeched as the relentless pistons pushed the ramp forward into position.
Inside Atlas, on the upper deck, the Gatling carriers were lined up in even rows that stretched from bow to stern. As soon as the great ship had entered the Thames, the tank crews began removing the shackles and turnbuckles that had secured them in place during the sea crossing. Kerosene lamps on the bulkheads provided barely enough light to accomplish this task.
Sergeant Corbett, driver of the lead machine, cursed as he barked his knuckles on the last recalcitrant shackle, pulled it free of the eye inset in the deck, and hurled it aside. As he did this, green electric lights in the ceiling came on, controlled from the ship’s bridge.
“Start your engines!” he bellowed. Drivers and gunners, down the length of the columns, jumped to the task. Private Hoobler, Corbett’s gunner, ran to the front of their machine and seized the starting handle. “Battery switch off!” he called out.