wall from which had come the painfully muffled sound. Then all sprang to their feet.

"Champagne, is it!" Kori exulted savagely. "Did I not say my eyes were those of a hawk?"

"Double guard all doors!" roared the Arvanian leader, to the guards outside. "Someone is in the house! And you in here," he went on in a lower tone, "see that this unseen one dies!"

Soyo and several other men whipped out automatics and pointed them at the wall. Thorn dropped to the floor. But with his quick action came Kori's voice.

"No, no! The sword, gentlemen. It is not so noisy, and covers a wider sweep."

Thorn shivered. Far rather would he have had bullets as his lot than cold steel. The prospect of being hacked to pieces, of gradually emerging from invisibility as a lump of gashed and bleeding flesh, turned him faint.

The Arvanians split up into orderly formation. Two went to guard the door to the butler's pantry, and two to cover the closed sliding doors to the outer hall. Six, with drawn swords sweeping back and forth before them, walked slowly toward the wall from which the sneeze had come.

Thorn set his jaws—only just catching himself in time to prevent his lips from opening in the half-snarl instinctive to the most civilized of men when danger is threatening. That lip motion would have revealed his teeth for an instant!

The sensation of perspiring heavily flamed over him again. There were so many trifling things to keep in mind! And each, if neglected, meaning certain death!

The nearest of the marching six stopped with his foot almost touching Thorn's hand. The dancing sword the man carried almost grazed the scientist's shoulder on its down sweep.

Thorn could not stay there. Lying flat along the baseboard, he would be stabbed at any instant by an inquiring sword point.

The six spread a little. A very little. But there was room enough for Thorn to slide between the two men nearest him and roll soundlessly under the table.

There was no sanctuary for him there. The cursed Kori, with his hawk eyes, glanced under the table after stabbing vainly along the wall.

"The carpet!" he bellowed. "See how the nap is pressed down! He is under there, comrades!"

The thrusting swords raked under the table a half second or so after Thorn had rolled out the other side, upsetting a chair in his hurry.

"After him!" panted Soyo. "By the living God, this is wizardry! But he must not get away—"

"He won't!" snapped the elderly leader. "Men, form a line at the far end of the room and march slowly, shoulder to shoulder, to this end. The spy must be caught!"

The move was executed. All the men in the room, save the four guarding the doors, lined up and advanced slowly, swerving and slashing their swords. Like a line of workers hand-harvesting a wheat field they came—foot by foot toward the corner where Thorn turned this way and that in a vain effort to escape.

The line reached the table. Over and under and around it the swords slashed viciously, leaving no space unprobed.

Thorn clenched his fists. He gazed at the packet containing the Ziegler plans. He gazed at the guarded door leading back to the kitchen. Then he tensed himself and leaped.

"The plans!" shouted Kori hoarsely. "Look—"

The vital packet, as far as the eye could see, had suddenly grown wings, soared from the table top, and was floating rapidly, convulsively, toward the door.

"Stop him!" yelled Soyo. "Stop—"

At that instant the heads of the two who guarded the door were dashed together. The door itself slammed open. The Ziegler plans sped into the butler's pantry.

The door to the kitchen began to open just as Kori reached the pantry. An oath burst from the Arvanian's lips. He flung his sword. In the air, shoulder high, appeared suddenly a small fountain of blood. Kori yelled triumphantly.

Thorn, feeling the warm drip following the glancing slash in his shoulder, knew the veil of invisibility had at last been rent. Abandoning efforts at noiselessness, knowing that his whereabouts was constantly marked by the packet in his hand, anyway, he fled through the kitchen to the rear door.

The bolt jerked back, under the astonished eyes of the five guards who had not yet realized precisely what the commotion was all about—and who only saw a packet of papers waving in mid-air, a trickle of blood appearing out of nothing, and a bolt banging open in its slot for no reason whatever.

Thorn's fingers worked feverishly at the chain. But before he could begin to get it undone, the guards had recovered from their surprise and had joined the Arvanians who poured in from the dining room under Kori's lead.

With a score of men crowding the kitchen, Thorn looped back in his tracks like a hunted creature, and sought the cellar door. Four men he upset, one after another, aided by the fact that his twisting body could be only approximately placed by the papers and the wound.

Then Kori's hand swept through the air above the waving packet, to clamp over Thorn's wrist.

With an effort—that bulged the muscles of that blacksmith's fore-arm of his till it seemed they must burst through the film, Thorn whirled Kori clear off his feet and sent him stumbling into the charge of three guards. But in the meantime the cellar was barred to him by a double line of men.

Fighting for his life—and, far more important, the existence of his country—Thorn lashed out with his invisible right fist while his left clutched the plans.

A score of men arrayed in a death struggle against one! But the odds were not twenty to one. Not quite. The score could mark Thorn's general whereabouts—but they could not see his flying right fist! That was an invisible weapon that did incredible damage.

But if they could not see the fist to guard against it, they could see the results of the fist's impacts. Here a nose suddenly crumpled and an instant later gushed red. There a head was snapped back and up, while its owner slowly sagged to the floor. And all the while the still dripping wound and the packet of documents kept with devilish ingenuity between the body of some swordless guard and the impatient blades of the Arvanian nobles.

Almost, it seemed to Thorn, he would win free. Almost, it appeared to the Arvanians, the unseen one would reach the big window near the door—which the path of his wreckage indicated was his goal. But one of the wildly swinging fists of a guard caught Thorn at last.

It landed on the glass cup over his right eye, cutting a perfect circle in the skin around the eyesocket, and tearing the film over the glass!

Now there were three things about the lithe, invisible body that the Arvanians could see: the crumpled papers, a slowly drying patch of blood that moved shoulder high in the air, and a blood-rimmed, ice-gray eye that glared defiance at them from apparently untenanted atmosphere.

Then came what seemed must be the end. Soyo appeared in the pantry doorway with a machine gun.

"Everybody to the end of the kitchen by the window!" he cried. "To the devil with silence—we'll spray this room with lead, and let the sound of shots bring what consequences it may!"

The men scattered. The machine gun muzzle swept toward the place where the eye, the papers, and the blood spot were to be seen.

That spot was now at one end of the great kitchen range on which a few copper pots simmered over white-hot electric burners. At the other end of the range, in the end wall of the kitchen, was a second window. It was small, less than a yard square, and had evidently been punched through the wall as an afterthought to carry off some of the heat of the huge stove.

Soyo's face twisted exultantly. The machine gun belched flame. Chasing relentlessly after the dodging, shifting blood spot, a line of holes appeared in the wall following instantly on the tap—tap—tap of the gun.

Eye and papers and blood spot appeared