said in a low tone, "I'm going to short theinduction-screen. We'll get across it. Then--out the door!"
* * * * *
She struggled to her feet, terrified, but instantly game. Thorn slidthe rod of metal across the stretch of flooring he had previously beenunable to cross. The induced currents in the rod amounted to ashort-circuit of the field. The rod grew hot and its paint blisteredsmokily. Thorn leaped across with Sylva in his wake. He pointed to thedoor, and she fled through it. He seized a chair, crashed itfrenziedly into the television screen, and had switched on the G.C.phone when there was a roar of fury from Kreynborg. Instantly therewas the spitting sound of a pocket-gun and in the red room the rackingcrash of a hexynitrate pellet. Nothing can stand the instant crash ofhexynitrate. Its concussion-wave is a single pulsation of the air. Thecellate diaphragm of the G.C. transmitter tore across from itsviolence and Thorn cursed bitterly. There was no way, now, ofsignaling....
A second racking crash as a second pellet flashed its tiny greenflame. Kreynborg was using a pocket-gun, one of those small terribleweapons which shoot a projectile barely larger than the graphite of alead pencil, but loaded with a fraction of a milligram of hexynitrate.Two hundred charges would feed automatically into the bore as thetrigger was pressed.
Thorn gazed desperately about for weapons. There was nothing in sight.To gain the outside world he had to pass before the doorway throughwhich the bullets had come.... And suddenly Thorn seized thecode-writer and the device which transmitted that code as a series ofunearthly noises which the world was taking for Martian speech. Heswung the two machines before the door in a temporary barrier.Whatever else Kreynborg might be willing to destroy, he would notshoot into them!
Thorn leaped madly past the door as Kreynborg roared with rage again.He paused only to hurl a chair at the two essential machines, and asthey dented and toppled, he fled through the door and away.
* * * * *
Sylva peered anxiously at him from behind a huge boulder. He racedtoward her, expecting every second to hear the spitting of Kreynborg'spocket-gun. With the continuous-fire stud down, the little gun wouldshoot itself empty in forty-five seconds, during which time Kreynborgcould play it upon him like a hose that spouted death. But Thorn haddone the hundred yards in eleven seconds, years before. He betteredhis record now. The first of the little green flashes came when he wasno more than ten yards from the boulder which sheltered Sylva. Thetiny pellet had missed him by inches. Three more, and he was safe frompursuit.
"But we've got to get away!" he panted. "He can shoot gas here and getus again! He can cover four hundred yards with gas, and more than thatwith guns."
They fled down a tiny water-course, midget figures in an infinity ofearth and sky, scurrying frenziedly from a red slug-like thing thatlay askew in a mountain valley. Far away and high above hung thewar-planes of the United Nations. Big ones and little ones, hoveringin hundreds about the outside of the dome of force they could neitherpenetrate nor understand.
A quarter of a mile. Half a mile. There was no sign from Kreynborg orthe rocket-ship. Thorn panted.
"He can't reach us with gas, now, and it looks like he doesn't dareuse a gun. They'd know he wasn't a Martian. At night he'll use thathelicopter, though. If we can only make those ships see us...."
* * * * *
They toiled on. The sun was already slanting down toward the westernsky. At four--by the sun--Thorn could point to a huge air-dreadnaughthanging by lazily revolving gyros barely two miles away. He wavedwildly, frantically, but the big ship drifted on, unseeing. TheFighting Force was no longer looking for Thorn and Sylva. They hadbeen carried into the rocket-ship fourteen hours and more before.Sylva's screaming had been broadcast with the weird hoots andwhistles the United Nations believed to be the language ofinter-planetary invaders. The United Nations believed them dead. Now awatch was being kept on the rocket-ship, to be sure, but it wasbecoming a matter-of-fact sort of vigilance, pending the arrival ofthe rest of the Fighting Force and the cracking of the dome of forceby the scientists who worked on it night and day.
On level ground, Thorn and Sylva would have reached the edge of thedome in an hour. Here they had to climb up steep hillsides and downprecipitous slopes. Four times they halted to make frantic efforts toattract the attention of some nearby ship.
It was six when they came upon the rim. There was no indication of itsexistence save that three hundred yards from them boughs waved andleaves quivered in a breeze. Inside the dome the air was utterlystill.
"There it is!" panted Thorn.
Wearied and worn out as they were, they hurried forward, and abruptlythere was something which impeded their movements. They could reachtheir hands into the impalpable barrier. For one foot, two, or eventhree. But an intolerable pressure thrust them back. Thorn seized asapling and ran at the barrier as if with a spear. It went five feetinto the invisible resistance and stopped, shot back out as if flungback by a jet of compressed air.
"He told the truth," groaned Thorn. "We can't get out!"
* * * * *
Long shadows were already reaching out from the mountains. Darknessbegan to creep upward among the valleys. Far, far away a compact darkcloud appeared, a combat-squadron. It swept toward the dome anddissociated into a myriad specks which were aircraft. The fliersalready swirling about the invisible dome drew aside to leave aquadrant clear, and Combat-Squadron Seven merged with the rest, makingthe pattern of dancing specks markedly denser.
"With a fire," said Thorn desperately, "they'll come! Of course! ButKreynborg took my lighter!"
Sylva said hopefully:
"Don't you know some way? Rubbing sticks together?"
"I don't," admitted Thorn grimly, "but I've got to try to invent one.While I'm at it, you watch for fliers."
He searched for dry wood. He rubbed sticks together. They grew warm,but not enough to smoke, much less to catch. He muttered, "A drill,that's the idea. All the friction in one spot." He tugged at the ringunder his lapel and the parachute fastened into his uniform collarshot out in a billowing mass of gossamer silk, flung out by thepowerful elastics designed to make its opening certain. Savagely, hetore at the shrouds and had a stout cord. He made a drill and revolvedit as fast as he could with the cord....
A second dark cloud swept forward in the gathering dusk and mergedinto the mass of fliers about the dome. Five minutes later, a third.Dense as the air-traffic was, riding-lights were necessary. They beganto appear in the deepening twilight. It seemed as if all the sky werealight with fireflies, whirling and swirling and fluttering here andthere. But then the fire-drill began to emit a tiny wisp of smoke.Thorn worked furiously. Then a tiny flickering flame appeared, whichhe nursed with a desperate solicitude. Then a larger flame. Then aroaring blaze! It could not be missed! A fire within the dome couldnot fail to be noted and examined instantly!
* * * * *
A searchlight beam fell upon them, illuminating him in a pitilessglare. Thorn waved his arms frantically. He had nothing with which tosignal save his body. He flung his arms wide, and up, and wide again,in an improvised adaption of the telegraphic alphabet togesticulation. He sent the watch call over and over again....
A little cloud of riding-lights swept toward the dome from an infinitedistance away. Darkness was falling so swiftly that they were stillmerely specks of light as they swept up to and seemed to melt into theswirling, swooping mass of fliers about the dome....
Cold sweat was standing out on Thorn's face, despite the violence ofhis exertions. He was even praying a little.... And suddenly thesearchlight beam flickered a welcome answer:
"W-e u-n-d-e-r-s-t-a-n-d. R-e-p-o-r-t."
Thorn flung his arms about madly, sending:
"G-e-t a-w-a-y q-u-i-c-k. C-o-m P-u-b-s h-e-r-e. W-i-l-l m-a-k-eo-t-h-e-r d-o-m-e o-u-t-s-i-d-e t-o t-r-a-p y-o-u."
The searchlight beam upon him flickered an acknow
ledgment. He knewwhat was happening after that. The G.C. phones would flash the warningto every ship, and every ship would dash madly for safety.... Asudden, concerted quiver seemed to go over the whirling maze of lightsaloft. A swift, simultaneous movement of every ship in flight. Thornbreathed an agonized prayer....
There was a flash of blue light. For one fractional part of a secondthe stars and skies were blotted out. There was a dome of flame abovehim and all about the world, of bright blue flame which instantlywas--and instantly was not!
Then there was a ghastly blast of green. Hexynitrate going off. Inthis glare were silhouetted a myriad motes in flight. But there was nonoise. A second flare.... And then Thorn Hard, groaning, saw flashafter flash after flash of green. Monster explosions. Colossalexplosions. Terrific detonations which were utterly soundless, as theships of the Fighting Force, in flight from the menace