Part 2

"You must be well aware of what the result of continued catastrophes of this sort will be. Already the wildest panic has gripped the section around Chicago, and the rest of the country. The whole world in fact is trembling upon the brink of a similar panic. The very uncertainty of these disasters encourages panic. None can say that the next blow will not be in his city and cut away his home and his life. All are aware now that your theory is correct, and that adds to the horror. For if a vessel or vessels with alien beings of some sort in it actually hover far above, none can say what greater horrors it may still loose upon us. We must strike back in some way, must drive these beings, whatever their nature, from the earth. Would there be any chance of doing so with dirigibles or planes, in your opinion?"

"Not a chance, sir," Dr. Howard replied at once. "The rarity of the atmosphere at its surface makes even an attempt impossible, for no ship of ours could ever reach the surface of the atmosphere."

"But what are we to do? Is there no method by which we can combat this menace? Must we lie supine and let whatever cataclysmic terror they choose descend on us?"

All eyes were upon Dr. Howard as he gravely answered. "Since I first comprehended what lay behind these catastrophes I have sought for some method of halting them, some method of striking back at whatever ship or ships from space are hovering over us. To find such a method I have had recourse to the same analogy that has been made so terribly clear to us, the analogy between ourselves at the bottom of our air-ocean and the creatures at the sea's bottom.

"Suppose those creatures far within the sea's depths had some intelligence and science, and suppose they wished to halt the trawling of our ships whose great scoops sweep down now and again upon them. How could they do so? They could not venture up to the ocean's surface. But one thing they could do, and that would be to send up something that would fight for them, that would make it impossible for the trawling ships to cruise longer on the surface!

"They could, granted science and intelligence enough, construct great mines in vast numbers. These, if attached to air-filled globes, would be swept instantly up to the ocean's surface when released. They would float there indefinitely, and any ships cruising to and fro would sooner or later strike one and be destroyed, unless they were warned by the previous destruction of one. In this way the creatures of the sea's depths could prevent our cruising above and trawling for them.

"And this is the way we must use to fight the beings who now cruise far above us! We must mine the air! We must send up thousands of great mines constructed so that they will float up to the surface of earth's atmospheric ocean and remain near that surface where, we know, the ships of these space-beings are coming and going. With thousands of mines floating about some of the invaders will inevitably be destroyed by a collision with one of them."

The others were silent for a moment. Then the Secretary of War broke out:

"Mine the air!" he repeated incredulously. "But how? How could any mine be constructed to float up in that way, so light as to float on the atmosphere's surface?"

By Means of _Steelite_

"There we have recourse again to our analogy," Dr. Howard declared. "If a mine attached to a great hollow globe of air were released at the sea's bottom it would rush up toward the surface and float there. In the same way, a mine attached to a great globe in which is a complete vacuum would rush up through our air-ocean!

"We can construct those globes of the strongest and lightest material known--_steelite_. As you all know, _steelite_ is the recently devised metal that has immensely greater strength than steel but the merest fraction of its weight. The tensile strength of a substance, its hardness and other qualities, depend directly upon the arrangement of its molecules. By the recent discoveries of Browning we know that when steelite is synthetically made the arrangement of the molecules is such that it forms an extremely strong and rigid substance. This gives the material unheard-of strength with unheard-of lightness.

"A forty-foot globe of _steelite_ can be made, with a charge of explosives of terrific power attached to it that will detonate when the globe is touched. This done, all air is exhausted from the hollow globe by great pumps, until the vacuum inside it is almost complete. The enormous strength of the steelite shell prevents its being crushed by the atmosphere's pressure as an ordinary steel shell would be.

"Released, the vacuum globe with its deadly charge will shoot up through the atmosphere with terrific speed. Its lightness for its size will be such that it will not halt until it floats on the very surface of our atmosphere. We will make these globes in countless thousands, each with its charge, and release them. Each globe will have a device that will repel any other, so that they do not detonate each other. We will sow the surface of our atmosphere with these deadly air-mines! Sooner or later the ship or ships cruising to and fro on our atmosphere's surface will strike one and will be destroyed by its detonating charge. In this way, and only in this way, can we fight back against the beings from space who are releasing this horror on us!"

"But to make these globes or mines in such numbers will engross all the earth's industrial activities!" the British ambassador exclaimed.

"It will," Dr. Howard agreed quietly. "But what of it? Have you not yet realized that a world crisis is upon us? Have you not yet realized that in this case there is no question of countries or races, of profits or dividends, or expediencies, but that we, as men, are fighting for the existence of man? That we are fighting against beings who may be immeasurably more advanced in knowledge and power than ourselves?"

"Dr. Howard is right," said the President. "Gentlemen, this emergency must be clear to you all, and I think that it is equally clear that Dr. Howard's plan is the only one that affords any possibility of combatting this terror from above. I place all the resources of the United States of America at your command, Dr. Howard, and I know that when the representatives of the other nations here have reported to their governments they will do the same. The whole world's efforts must concentrate upon the prevention of these terrible disorders."

"There is but one thing earth's peoples can do," Dr. Howard said. "Make air-mines! Thousands, tens of thousands--they must be turned out in ceaseless floods and released. For it is only with them that we can repel the menace above us."

Make air-mines! It was the watchword of all earth's races within a few hours of that momentous meeting. For the President and the heads of the earth's other governments sent statements in which Dr. Howard's suggested method of combatting the danger was stressed as the world's one chance. Thousands of air-mines must be made at once and continue to be turned out until the menace was repelled--scientists agreed, as one man, that it was the one possible way of fighting these grim visitors from space who were hovering in their enigmatic vessels at the surface of our atmosphere.

Within a half day after the meeting Dr. Howard and I, aided by several masters of aeronautical, chemical, and physical sciences had drawn up the plans of the air-mines. Each was to be a hollow steelite globe forty-two feet in outside diameter. This would give the globes a gross lifting power of about five thousand pounds and net of about twenty-five hundred. Attached in a special chamber at the side of each was the charge, a load of the most modern explosives, small in bulk but terrific in power, while striking-pins on the globe's sides made it inevitable that the charge be exploded whenever the globe was struck.

Through the night of the 6th, hundreds of men were busy in Washington turning out copies of the simple plans of the air-mine, and scores of planes were flying throughout the world with copies for all nations. On the 7th the manufacture of the great engines had already been begun in a hundred cities.

But on the night of the 7th the terror struck again. This time it was with small loss of life, but the psychological effects were far greater. It was upon upper Malaysia that the giant, glittering trawl descended, flashing down to rip a great trench of destruction through the jungle and along the edge of a native village, then flashing up again, leaving untold panic behind it.

The First Globe

As best they could, the governments of earth sought to dissipate the panic, pointing out that few lives had been lost, and urging greater efforts in the production of the air-mines. Already the first great steelite globes were rolling out of the big factories, and were quickly being fitted with the charge of explosives.

It was early on the morning of the 12th that the first air-mine was finished and released. Dr. Howard and I superintended the process, which took place outside one of the great Pittsburgh _steelite_ works that was turning out the globes. Anchored securely to the ground, the globe was slowly exhausted of its air by the giant air-pump that had been equipped for the task.

The pump was disconnected. Then the globe was removed to a large open field near-by and reanchored. We could see clearly that the mighty globe, of incredible lightness, was straining upward with such force against the anchoring chains that held it that it seemed they must part. Dr. Howard reached forth and turned the lever that held the great globe anchored. There was a whizzing sound, a puff of air in our faces, and the great air-mine had vanished, rushing upward at such tremendous speed that it had seemed to disappear before our eyes.

We all gazed up after it, as though to follow its course upward until it floated at last on the surface of earth's atmosphere. I think that the same thought held us all. This air-mine, this single globe we had released--it seemed such a puny weapon to use against beings who from mighty ships had let down the colossal trawl upon us. Was there actually any hope for us in this method?

Perhaps this doubt was felt by many then, but there was no cessation of the work, which after all held our only chance of striking back at the great space invaders above. By the next day, here and there over earth's surface, scores of the air-mines were being released, to rush upward. In Germany and the English midlands, in Russia and Pennsylvania and Indiana--everywhere on earth's surface where the air-mines could be made and assembled--they were being released in groups.

The great industrial leaders of the world had gathered, under Dr. Howard's heading, to devise plans for the quantity production of the air-mines with the greatest possible speed. Already great factories were being hastily equipped with special machinery, and the explosive factories of the world as well as those producing the repelling devices were working night and day to manufacture the needed materials.

By the 15th, scores of the globes were being released each hour, here and there over the world, and their number was rapidly increasing. Dr. Howard was sleeping but two hours out of twenty-four, it seemed, remaining night and day at the Washington office that had become the center of the world's activities. He estimated that within a week the air-mines would be pouring forth at the rate of a thousand a day.

"The great danger," he said, "is that the next attack on us might hit one of the great cities so hard that the inevitable panic will cause a cessation on work on the air-mines."

"But how long is the work to go on in any case?" I asked. "There must be thousands of globes floating already upon the atmosphere's surface."

"There need to be tens of thousands, hundreds of thousands," he said solemnly. "They must be sent forth until these terrible trawlings from above have entirely ceased."

I shook my head, for I could see that already many, tired of the ceaseless work, were crying out that the scheme was a crazy one. Others had begun to say that whatever space-visitors had been above had already departed. But these statements were swiftly silenced on the next morning, that of the 16th, by the fifth catastrophe.

This fifth blow took place at one of New York's residential suburbs, Scarsdale, and while it took a toll of life exceeded only by that of the Chicago horror, it was different from the others in one odd respect. The great trawl seemed to descend and gouge along the earth with somewhat smaller speed than in the other instances, and was seen very plainly and even escaped from in time by some people in the vicinity.

It was described as being very like the familiar steam-shovel scoop in shape, but of a glittering metal that all agreed was not native to the earth. The top of it, what supported it, ran up into the mists of the morning sky. They were many shining strands, and very slender for the colossal weight they supported. They gleamed with strange light and it was the opinion of many that if they were of metal they had in some unheard-of way been given supernatural strength.

At Scarsdale perhaps twelve hundred perished in the sweep of the giant scoop, which seemed to make a smaller gash than usual. A few who had heard the trawl crashing toward them had managed to flee from its path in time to escape it.

Hope and Fear

This fifth catastrophe marked the beginning of the terror's last period. Until then earth's peoples had hoped against hope that in some unexplained way the whole business was the result of natural forces, but now they could no longer doubt that far overhead were hovering vessels or vehicles dragging their trawls here and there over the earth's surface for their own unfathomable purposes. Dread was upon the earth! At any moment of day or night the giant trawl might crash down in terrible annihilation.

It was the sword of Damocles, suspended over a helpless world!

The days after the Scarsdale terror saw the world's activities at their most intense pitch. Dr. Howard and I were occupied without end in the direction of the manufacture and distribution of the air-mines. For he was now having them released, not at the factories where they were assembled, but at various points over the earth, so that they would cover more uniformly the surface of the atmospheric ocean.

Day after day we sent them out. I know that to me those days were part of a dream of nightmare activity and tension. Again the world was waiting in dread for the coming of the great trawl. It did not come again, for reasons which we shall never guess, until the 19th. That interval of three days between trawlings was the longest that had yet elapsed. We owe much to it. Perhaps our world.

For in those days the air-mines were whizzing upward in fast-increasing numbers. By the 19th they were ascending at the rate of more than a thousand a day. All of earth's peoples, in the industrial regions at least, seemed toiling upon the one task of making the great globes. The world's hopes were raised. We were winning, it seemed, by sowing the atmosphere's surface thick with air-mines that sooner or later must demolish all or part of the space invaders. We were exultant, even. And then--

Shortly after dark on the 19th a trawl flashed down to gouge most of the town of Martiana, in southern Norway, from the face of the earth.

On the morning of the 20th another trawl, or the same one, descended and gouged the bed of the Mediterranean just off Capri and in full sight of its shore.

A little before noon on the 21st a trawl was glimpsed plowing a vast wound in the Sudan desert near a British outpost. And three hours later a trawl cut a terrific trail of annihilation squarely across the city of Algiers.

Earth and the races of the earth rocked beneath those fearful cataclysms, striking in such swift succession. With them the activities upon which our races of man had been so fearfully bent--the manufacture of the air-mines--began to dwindle. By the 20th the number of air-mines released had fallen off a little, and after the catastrophes of that and the next day it was even smaller. Dr. Howard's reports showed that on the 22nd but four hundred air-mines had been released in comparison with the twelve hundred released but three days before.

Mankind was giving up the battle in despair!

Panic was breaking loose over the earth, a panic and dread that nothing could restrain. Toiling thousands quit their work upon the manufacture of air-mines in hopeless despair. Mobs began to appear in the streets of London, New York, Shanghai, and Sydney, and rioting became general. The world was going mad with fear!

Dr. Howard strove above all else to keep the manufacture of the air-mines going. Under his urgent pleadings the governments of earth used their troops to protect and continue that manufacture as well as might be, instead of using them to suppress the growing riots. The production of the globes leaped again to almost a thousand a day. Each day saw them whizzing up to join the thousands upon thousands already floating at the surface of earth's atmosphere.

And yet it seemed all so futile. It was not like striking back at a visible enemy, this frantic manufacture and release of the mines. Men would have been happier by far, I think, had they faced more terrible enemies in the plain light of day. I know that in those last days of an apparently disintegrating world I would have been easier in mind.

"It's a race against time now, Ransome," said Dr. Howard. "We cannot continue the production of air-mines much longer--and civilization is crashing now!"

"But is there no other way?" I cried. "My God, Howard, these air-mines are useless--we've sent up tens of thousands and they can be no more than a sprinkling in the vast extent of the atmosphere's surface. To try some other way--"

"There is no other!" he exclaimed. "Ransome, we must fight it out to the end! The air-mines--they're our one chance!"

"But we can't send up many more," I said. "The rioting in Germany has become so bad that all the factories save two that were making mines there have quit. We've no more than a dozen factories left in Europe and hardly more than that in America!"

"As long as we can release one mine we'll do so!" he declared. "Man's crisis is here--and he's got to have the courage now to fight in the dark against an unknown foe for his existence!"

Somehow Dr. Howard's indomitable will held together in those last days the thread of organization between the factories and their sources of supply, despite the wide-spread outbreaks that were going on. Fewer and fewer were becoming the air-mines released, but still they were being made and sent whizzing upward.

But on the 25th it became apparent to all that our last efforts were flickering out. Then late on that day came news of the tenth trawl. It had descended a hundred miles south of Rio de Janeiro to crash across a plantation with the loss of a score of lives. And hardly had that dread news spread around the earth than came word that the trawl had again flashed down a few hours later to gouge a terrific scar from the side of one of the peaks of the Peruvian Andes.

The end! With the spreading of those two reports it seemed so. For they so deepened the blind and unreasoning fear that had gripped mankind that the production of air-mines all but ceased on that day, only a few dozens continuing to be assembled and released. Panic-mad mobs caused chaos in the greater cities. Every organization of civilization seemed breaking down, and troops called to suppress wild outbreaks fought pitched battles with the mobs.

On the night of the 26th came the crisis for mankind. For it was known that all man's efforts to halt the menace from above had failed, that mankind lay defenseless beneath the grim and terrible invaders from beyond, who might at any time loose even greater horrors upon us. Man had fought an enemy he had never even seen and had lost! He had fought an enemy who apparently cared no more for the wrecking of mankind far beneath than we do of the insects beneath our feet!

Victory?

Through the hours of that dread night I sat with Dr. Howard and with the last of our remaining organization in the Washington office. Outside, to the east the sky was red with the glow of flames, where a mob had set fire to looted buildings. From afar we heard the crackle of shots, the rumble of hurrying tanks, and the wild uproar of cries as troops sought to bring order out of the chaos of a dissolving civilization. We were silent, in a silence that made each minute age-long. And it was there, silent, almost toward morning, that the last messenger of mankind's hope found us.

He was a dishevelled young radio operator and it was some moments before we comprehended what he was babbling frantically forth to us. When we did, twenty minutes saw us in the air and speeding southward through the night with an army aviator.

Over the fear-mad, riot-blazing city and through the night out over other cities we sped, at the plane's utmost velocity, Dr. Howard peering ahead with face set, I gripping the cockpit's rim with nervous, trembling fingers. We were still speechless as our plane raced southward. It was not until dawn was streaking the sky eastward that the plane bumped down into a field a few miles from a little Georgia village.

We found men awaiting us, in uniform and civilian clothes, and all were half-hopeful, half-awed. Swiftly they told us what had happened.

Shortly after midnight citizens near the village had heard a faint, almost inaudible but clear sound of detonation, coming as though from far above. Almost in the next instant had come another detonating sound, as faint as the first, and then silence. But a few instants later, coming from the west of the village, they heard in quick succession two terrific prolonged crashings as of some thing or things falling from an immense height.

They had thought the trawl was descending on them, at first, and had fled from it for some distance. But after moments of hesitation they had made their way to the scene of the crashes, and what they found had made them get word quickly to the soldiers in a near-by town, whose first act had been to radio Dr. Howard.