did vanish while they were smelting the gold. Poor Mr. Tom James. I suppose he ventured away from the rest, and something caught him."

The few entries that followed were shorter, and showed increasing nervous tension. They recorded the departure from Titania, made almost as soon as the treasure was loaded. The last was made several weeks later. A dozen men had vanished from the crew, leaving only gouts of blood to hint the manner of their going. The last entry ran:

"Dad says I'm to stay in here to-day. Old dear, he's afraid the thing will get me—whatever it is. It's really serious. Two men taken from their berths last night. And not a trace. Some of them think it's a curse on the treasure. One of them swears he saw Dad's stuffed specimens moving about in the hold.

"Some terrible thing must have slipped aboard the flier, out of the jungle. That's what Dad and the captain think. Queer they can't find it. They've searched all over. Well...."

Musing and regretful, Thad turned back for another look at the smiling girl in the photograph.

What a tragedy her death had been! Reading the diary had made him like her. Her balance and humor. Her quiet affection for "Dad." The calm courage with which she seemed to have faced the creeping, lurking death that darkened the ship with its unescapable shadow.

How had her body come to be in the coffer, he wondered, when all the others were—gone? It had shown no marks of violence. She must have died of fear. No, her face had seemed too calm and peaceful for that. Had she chosen easy death by some poison, rather than that other dreadful fate? Had her body been put in the chest to protect it, and the poison arrested decomposition?

Thad was still studying the picture, thoughtfully and sadly, when the dog, which had been silent, suddenly growled again, and retreated from the door, toward the corner of the room.

The invisible monster had returned. Thad heard its claws scratching across the door again. And he heard another dreadful sound—not the long, shrill scream that had so grated on his nerves before, but a short, sharp coughing or barking, a series of shrill, indescribable notes that could have been made by no beast he knew.

The decision to open the door cost a huge effort of Thad's will.

For hours he had waited, thinking desperately. And the thing outside the door had waited as patiently, scratching upon it from time to time, uttering those dreadful, shrill coughing cries.

Sooner or later, he would have to face the monster. Even if he could escape from the room and avoid it for a time, he would have to meet it in the end. And it might creep upon him while he slept.

To be sure, the issue of the combat was extremely doubtful. The monster, apparently, had succeeded in killing every man upon the flier, even though some of them had been armed. It must be large and very ferocious.

But Thad was not without hope. He still wore his Osprey-suit. The heavy fabric, made of metal wires impregnated with a tough, elastic composition, should afford considerable protection against the thing.

The welding arc, intended to fuse refractive meteoric iron, would be no mean weapon, at close quarters. And the quarters would be close.

If only he could find some way to make the thing visible!

Paint, or something of the kind, would stick to its skin.... His eyes, searching the room, caught the jar of face powder on the dressing table. Dash that over it! It ought to stick enough to make the outline visible.

So, at last, holding the powder ready in one hand, he waited until a time when the pressure upon the door had just relaxed, and he knew the monster was waiting outside. Swiftly, he opened the door....

Thad had partially overcome the instinctive horror that the unseen being had first aroused in him. But it returned in a sickening wave when he heard the short, shrill, coughing cries, hideously eager, that greeted the opening of the door. And the quick rasping of naked claws upon the floor. Sounds from nothingness!

He flung the powder at the sound.

A form of weird horror materialized before him, still half invisible, half outlined with the white film of adhering powder: gigantic and hideous claws, that seemed to reach out of empty air, the side of a huge, scaly body, a yawning, dripping jaw. For a moment Thad could see great, hooked fangs in that jaw. Then they vanished, as if an unseen tongue had licked the powder from them, dissolving it in fluids which made it invisible.

That unearthly, half-seen shape leaped at him.

He was carried backward into the room, hurled to the floor. Claws were rasping upon the tough fabric of his suit. His arm was seized crushingly in half-visible jaws.

Desperately he clung to the welding tool. The heated electrode was driven toward his body. He fought to keep it away; he knew that it would burn through even the insulated fabric of his suit.

A claw ripped savagely at his side. He heard the sharp, rending sound, as the tough fabric of his suit was torn, and felt a thin pencil of pain drawn along his body, where a claw cut his skin.

Suddenly the suit was full of the earthy fetor of the monster's body, nauseatingly intense. Thad gasped, tried to hold his breath, and thrust upward hard with the incandescent electrode. He felt warm blood trickling from the wound.

A numbing blow struck his arm. The welding tool was carried from his hand. Flung to the side of the room, it clattered to the floor; and then a heavy weight came upon his chest, forcing the breath from his lungs. The monster stood upon his body and clawed at him.

Thad squirmed furiously. He kicked out with his feet, encountering a great, hard body. Futilely he beat and thrust with his arms against the pillarlike limb.

His body was being mauled, bruised beneath the thick fabric. He heard it tear again, along his right thigh. But he felt no pain, and thought the claws had not reached the skin.

It was the yellow dog that gave him the chance to recover the weapon. The animal had been running back and forth in the opposite end of the room, fairly howling in excitement and terror. Now, with the mad courage of desperation, it leaped recklessly at the monster.

A mighty, dimly seen claw caught it, hurled it back across the room. It lay still, broken, whimpering.

For a moment the thing had lifted its weight from Thad's body. And Thad slipped quickly from beneath it, flung himself across the room, snatched up the welding tool.

In an instant the creature was upon him again. But he met it with the incandescent electrode. He was crouched in a corner, now, where it could come at him from only one direction. Its claws still slashed at him ferociously. But he was able to cling to the weapon, and meet each onslaught with hot metal.

Gradually its mad attacks weakened. Then one of his blind, thrusting blows seemed to burn into a vital organ. A terrible choking, strangling sound came from the air. And he heard the thrashing struggles of wild convulsions. At last all was quiet. He prodded the thing again and again with the hot electrode, and it did not move. It was dead.

The creature's body was so heavy that Thad had to return to the bridge, and shut off the current in the gravity plates along the keel, before he could move it. He dragged it to the lock through which he had entered the flier, and consigned it to space....

Five days later Thad brought the Red Dragon into the atmosphere of Mars. A puzzled pilot came aboard, in response to his signals, and docked the flier safely at Helion. Thad went down into the hold again, with the astonished port authorities who had come aboard to inspect the vessel.

Again he passed among the grotesque and outrageous monsters in the hold, leading the