After supper the two friends ascended to the deck saloon for a smoke, and to continue their discussion of the tremendous events in which they were so soon to be taking part. They found the Ariel flying through a cloudless sky over the German Ocean, whose white-crested billows, silvered by the moonlight, were travelling towards the northeast under the influence of the south-west breeze from which the engineer had promised himself assistance when they started.
"We seem to be going at a most frightful speed," said Colston, looking down at the water. "There's a strong southwest breeze blowing, and yet those white horses seem to be travelling quite the other way."
"Yes," replied Arnold, looking down. "This wind will be travelling about twenty miles an hour, and that means that we are making nearly a hundred and fifty. The German Ocean here is five hundred miles across, and we shall cross it at this rate in about three hours and a half, and if the wind holds over the land we shall sight Petersburg soon after sunrise.
"The sun will rise to-morrow morning a few minutes after five by Greenwich time, which is about two hours behind Petersburg time. Altogether we shall make, I expect, from two to two and a half hours' gain on time."
The two men talked until a few minutes after ten, and then went to bed. Colston, who had been travelling all the previous night, began to feel drowsy in spite of the excitement of the novel voyage. and almost as soon as he lay down in his berth dropped off into a sound, dreamless sleep, and knew nothing more until Arnold knocked at his door and said--
"If you want to see the sun rise, you had better get up. Coffee will be ready in a quarter of an hour."
Colston pulled back the slide which covered the large oblong pane of toughened glass which was let into the side of his cabin and looked out. There was just light enough in the grey dawn to enable him to see that the Ariel was passing over a sea dotted in the distance with an immense number of islands.
"The Baltic," he said to himself as he jumped out of bed. "This is travelling with a vengeance! Why, we must have travelled a good deal over a thousand miles during the night. I suppose those islands will be off the coast of Finland. If so, we are not far from Petersburg, as the Ariel seems to count distance."
The most magnificent spectacle that Colston had ever seen in his life, or, for the matter of that, ever dreamed of, was the one that he saw from the conning-tower of the Ariel while the sun was rising over the vast plain of mingled land and water which stretched away to the eastward until it melted away into the haze of early morning.
The sky was perfectly clear and cloudless, save for a few light clouds that hung about the eastern horizon, and were blazing gold and red in the light of the newly-risen sun. The air-ship was flying at an elevation of about two thousand feet, which appeared to be her normal height for ordinary travelling. There was land upon both sides of them, but in front opened a wide bay, the northern shores of which were still fringed with ice and snow.
"That is the Gulf of Finland," said Arnold. "The winter must have been very late this year, and that probably means that we shall find the eastern side of the Ourals still snow-bound."
"So much the better," replied Colston. "They will have a much better chance of escape if there is good travelling for a sleigh."
"Yes," replied Arnold, his brows contracting as he spoke. " Do you know, if it were not for the Master's explicit orders, I should be inclined to smash up the station at Ekaterinburg a few hours beforehand, and then demand the release of the whole convict train, under penalty of laying the town in ruins."
Colston shook his head, saying--
"No, no, my friend, we must have a little more diplomacy than that. Your thirst for the life of the enemy will, no doubt, be fully gratified later on. Besides, you must remember that you would probably blow some hundreds of perfectly innocent people to pieces, and very possibly a good many friends of the Cause among them."
"True," replied Arnold; "I didn't think of that; but I'll tell you what we can do, if you like, without transgressing our instructions or hurting any one except the soldiers of the Tsar, who, of course, are paid to slaughter and be slaughtered, and so don't count."
"What is that?" asked Colston.
"We shall be passing over Kronstadt in a little over an hour, and we might take the opportunity of showing his Majesty the Tsar what the Ariel can do with the strongest fortress in Europe. How would you like to fire the first shot in the war of the Revolution?"
Colston was silent for a few moments, and then he looked up and said--
"There is not the slightest reason why we should not take a shot at Kronstadt, if only to give the Russians a foretaste of favours to come. Still, I won't fire the first shot on any account, simply because that honour belongs to you. I'll fire the second with pleasure."
"Very good," replied Arnold. "We'll have two shots apiece, one each as we approach the fortress, and one each as we leave it. Now come and take a preparatory lesson in the new gunnery."
They went down into the chief saloon, and there Arnold showed Colston a model of the new weapon with which the Ariel was armed, and thoroughly explained the working of it. After this they went to the wheel-house, where Arnold inclined the planes at a sharper angle, and sent the Ariel flying up into the sky, until the barometer showed an elevation of three thousand feet.
Then he signalled to the engine-room, the fan-wheels rose from the deck, as if by their own volition, and, as soon as they reached their places, began to spin round faster and faster, until Colston could again hear the high-pitched singing sound that he had heard as the Ariel rose from Drumcraig Island.
At the same time the speed of the vessel rapidly decreased; the side propellers ceased working, and the stern-screw revolved more and more slowly, until the speed came down to about thirty miles an hour.
By this time the great fortress of Kronstadt could be distinctly seen lying upon its island, like some huge watch-dog crouched at the entrance to his master's house, guarding the way to St. Petersburg.
"Now," said Arnold, "we can go outside without any fear of being blown off into space." They went out and walked forward to the bow. Arrived there they found two of the men, each with a curious-looking shell in his arms. The projectiles were about two feet long and six inches in diameter, and were, as Arnold told Colston, constructed of papier-maché. There were three blades projecting from the outside, and running spirally from the point to the butt. These fitted into grooves in the inside of the cannon, which were really huge air-guns twenty feet long, including the air-chamber at the breech.
The projectiles were placed in position, the breeches of the guns closed, and a minute later the air-chambers were filled with air at a pressure of two hundred atmospheres, pumped from the forward engines through pipes leading up to the guns for the purpose.
"Now," said Arnold, "we're ready! Meanwhile you two can go and load the two after guns."
The men saluted and retired, and Arnold continued--
"Just take a look down with your glasses and see if they see us. I expect they do by this time."
Colston put his field-glass to his eyes, and looked down at the fortress, which was now only six or seven miles ahead.
"Yes," he said, "at any rate I can see a lot of little figures running about on the roof of one of the ramparts, which I suppose are soldiers. What's the range of your gun? I should say the fortress is about six miles off now."
"We can hit it from here, if you like," replied Arnold, "and if we were a thousand feet higher I could send a shell into Petersburg. See! there is the City of Palaces. Away yonder in the distance you can just see the sun shining on the houses. We could see it quite plainly if it wasn't for the haze that seems to be lying over the Neva."
While he was speaking, Arnold trained the gun according to a scale on a curved steel rod which passed through a screw socket in the breech of the piece.
"Now," he said. "Watch!"
He pressed a button on the top of the breech. There was a sharp but not very loud sound as the compressed air was released; something rushed out of the muzzle of the gun, and a few seconds later, Colston could see the missile boring its way through the air, and pursuing a slanting but perfectly direct path for the centre of the fortress.
A second later it struck. He could see a bright greenish flash as it smote the steel roof of the central fort. Then the fort seemed to crumble up and dissolve into fragments, and a few moments later a dull report floated up into the sky mingled, as he thought, with screams of human agony.
For a moment he stared in silence through the glasses, then he turned to Arnold and said in a voice that trembled with violent emotion--
"Good God, that is awful! The whole of the centre citadel is gone as though it had been swept off the face of the earth. I can hardly see even the ruins of it. Surely that's murder rather than war!"
"No more murder than the use of torpedoes in naval warfare, as far as I can see," replied Arnold coolly. "Remember, too," he continued in a sterner tone, "that fortress belongs to the power that flogged Radna and has captured Natasha. Come, let's see what execution you can do."
He crossed the deck and set the other gun by its scale, saying as he did so--
"Put your finger on the button and press when I tell you."
Colston did as he was bid, and as his finger touched the little knob his hand was as firm as though he had been making a shot at billiards.
"Now!"
He pressed the button down hard. There was the same sharp sound, and a second messenger of destruction sped on its way towards the doomed fortress.
They saw it strike, and then came the flash, and after that a huge cloud of dust mingled with flying objects that might have been blocks of masonry, guns, or human bodies, rose into the air, and then fell back again to the earth.
"There goes one of the angles of the fortification into the sea," said Arnold, as he saw the effects of the shot. "Kronstadt won't be much good when the war breaks out, it strikes me. I suppose they'll be replying soon with a few rifle shots. We'd better quicken up a bit."
He went aft to the wheel-house, followed by Colston, and signalled for the three propellers to work at their utmost speed. The order was instantly obeyed; the fan-wheels ceased revolving, and under the impetus of her propellers the Ariel leapt forwards and upwards like an eagle on its upward swoop, rose five hundred feet in the air, and then swept over Kronstadt at a speed of more than a hundred miles an hour.
As they passed over they saw a series of flashes rise from one of the untouched portions of the fortress, but no bullets came anywhere near them. In fact, they must have passed through the air two or three miles astern of the flying Ariel. No soldier who ever carried a rifle could have sent a bullet within a thousand yards of an object seventy feet long travelling over a hundred miles an hour at a height of nearly four thousand feet, and so the Russians wasted their ammunition.
As soon as they had passed over the fortress, Arnold signalled for the propellers to stop, and the fan-wheels to revolve again at half speed. The air-ship stopped within three miles, and remained suspended in air over the opening mouth of the Neva Then the two after guns were trained upon the fortress, and Colston and Arnold fired them together.
The two shells struck at the same moment, one in each of two angles of the ramparts. Their impact was followed by a tremendous explosion, far greater than could be accounted for by the shells themselves.
"There goes one, if not two, of his powder magazines. Look! half the fortress is a wreck. I wonder which fired the lucky shot."
The man who a year before had been an inoffensive student of mechanics and an enthusiast dreaming of an unsolved problem, spoke of the frightful destruction of life and the havoc that he had caused by just pressing a button with his finger, as coolly and quietly as a veteran officer of artillery might have spoken of shelling a fort.
There were two reasons for this almost miraculous change. One was to be found in the bitter hatred of Russian tyranny which he had imbibed during the last six months, and the other was the fact that the woman for whom he would have himself died a thousand deaths if necessary, was a captive in Russian chains, being led at that moment to slavery and degradation.
As soon as they had seen the effects of the last two shots, Arnold said with a grim, half-smile on his lips--
"I think it will be better if we don't show ourselves too plainly to Petersburg. It will take some time for the news of the destruction of Kronstadt to reach the city, and, of course, there will be the wildest rumours as to the agency by which it was done, so we may as well leave them to argue the matter out among themselves."
He signalled again to the engine-room, and with the united aid of her planes and fan-wheels the Ariel mounted up and up into the sky, driven only by the stern-propeller and with the force of the other engines concentrated on the lifting wheels, until a height of five thousand feet was reached.
At that height she would have looked, if she could have been seen at all, nothing, more than a little grey spot against the blue of the sky, and as they heard afterwards she passed over St. Petersburg without being noticed.
From St. Petersburg to Tiumen, as the crow flies, the distance is 1150 English miles, and nine hours after she had passed over the Capital of the North, the Ariel had winged her way over the Ourals and the still snow-clad forests of the eastern slopes, past the tear-washed Pillar of Farewells, and had come to a rest after her voyage of two thousand two hundred miles, including the delay at Kronstadt, in twenty hours almost to the minute, as her captain had predicted.