It was midnight when the liner reached San Francisco, but Holden insisted on going at once to the offices of the Interplanetary Transportation Company, where work was carried on day and night. Fortunately they found an official of the company who had sufficient power to carry out their instructions.

It is unnecessary to go into the details of the meeting, or of the ensuing days. The unlimited power given Holden, together with the vital importance of his mission, brought everyone into instant cooperation.

Three mammoth space ships were turned over to the gang of mechanics he had hired, to be fitted with projectors for the anti-gravitational screens. Thousands of chemists all over the world dropped their work to prepare the precious hexoxen while others extracted Europium from the rare minerals in which it was found. Special freight ships were sent out to gather together the supply of these materials upon which the fate of the earth depended, and rapidly the great quantities of the chemical necessary were stored in the ships.

Captain Linet had proven true to his word, and, with his great executive ability, had made himself invaluable.

It was a pleasant sight to see the huge old Captain, veteran of many a storm in the air, conferring with the slim young Holden, whose pleasant features and soft voice gave no real notion of the immense energy, fiery courage and scientific knowledge which he possessed.

Crews for the three ships had to be assembled. Holden and Erickson picked many from among the scientific men of their acquaintance, all experts in their lines. The Interplanetary Transportation Company recommended several of their best men for the positions on board requiring technical knowledge of the handling of space ships, and Captain Linet also picked up a few of his friends—brave, strong men. There were to be fifty on each ship.

The start had been scheduled for the fifteenth of the month, but on the tenth Professor Erickson received a radiogram from the Seismographical Institute which read as follows: "Observations indicate a series of stresses approaching Pacific fault, probably aggravated by unusual tidal action of moon in that area tenth of next month."

"Gentlemen," the old professor addressed the little group gathered in the office allotted them in the I. T. C. building, "as you know, this is the tenth. Without allowing for possible delays, we would just have time, starting tomorrow, to reach the moon, distribute the hexoxen and Europium and get out of range by the first. That would leave us only ten days for cutting the gaseous mass into small pieces which will drift harmlessly into space. If we do not have that task accomplished by the time indicated in this message, Los Angeles, San Francisco, Portland and Seattle will suffer the fate which overtook New York such a short time ago."

Holden's face was pale as he rose and nodded to the professor. "If Captain Linet will take the responsibility of getting the crews on board, I will see that we are ready to leave at high noon tomorrow."

The meeting adjourned in a flurry of papers, a ringing of bells, and brisk words spoken into television transmitters.

All that night and all the next morning work went on. At eleven A. M. the last five hundred tons of hexoxen was loaded on the San Francisco, which was to be the flagship; at noon exactly the huge doors swung shut, the repulsion tubes at the stern began to glow, and the beautiful cigar-shaped ship rose from the earth, followed immediately by the Los Angeles and the Ganymede. They cruised slowly, at about six hundred miles per hour, until they were well out of the earth's atmosphere, when full power was slowly turned on, and the trip to the moon was actually begun.

Holden and Erickson stood in the bow of the San Francisco, watching the skilful hands of the pilot, Edwards, as he spun the dials controlling the steering discharges, keeping the delicate needle in the direction indicator exactly in line with the path indicated on the chart before him.

"How are things going, Edwards?" Holden asked.

"Fine so far. We have developed our necessary velocity in very good time. If you would allow me a word of advice, I would suggest that you turn in now, as the tremendous acceleration of the last few minutes, and the speed with which we are now traveling, are liable to affect you disagreeably, since this is your first trip. Our course has been plotted by the experts of the I. T. C., and there is nothing to do now but to stay on it."

Holden decided that the suggestion was a good one, as he was beginning to feel light-headed and slightly bewildered. Erickson, however, chose to go down to the observation room, for a glance at the earth, and the two parted company in the hall which led through the storage compartments, located amidships.

As Holden continued on down the hall toward his cabin, a sudden feeling of danger came over him. Memories of the clutching hands that had endeavored to throttle the life out of him shot into his mind. He laughed to himself, attributing the fear to the mental disorganization suffered by travelers on their first trip into space. He opened the door of his cabin, and stepped inside, instinctively reaching for the light-switch.

His hand encountered warm flesh! Swiftly he went into action, diving for the stranger's throat, but his unknown antagonist had the advantage of being prepared. Holden heard a soft swish, a tremendous weight seemed to descend on him, crushing his entire body. Buzzing lights flashed before his eyes. Then came darkness, and he sank, unconscious, to the floor.

"Jack, Jack, my boy." The voice came from a great distance, slowly penetrating the great cloud which hung over him. "Jack, what's the matter with you?" He realized that someone was talking to him. With a mighty effort, he opened his eyes and endeavored to distinguish the speaker among the thousands of objects which whirled before his eyes. At last things settled down, and he saw the anxious faces of Erickson and Captain Linet bending above him.

"Somebody was in my cabin, and slugged me over the head with a black-jack when I came in. Look at the wall-cabinet, will you, professor, and see if any of the papers are missing?"

The professor stepped over to one side of the room, and bent to examine the compartment set in the solid metal of the wall.

"Holden," he cried, "the intruder tried to open the cabinet, but was unable to do so, or else you came back sooner than he had expected. There are tool marks all around the lock."

"That means," exclaimed Captain Linet, "that the man either has tools in his cabin, or has access to the machine shop here on board."

Scarcely had he spoken when the floor leaped beneath their feet, a deafening roar sounded from the bow, and the lights went out. Sounds of running feet came from the corridor. The three men picked themselves up from the positions into which they had been thrown by the force of the shock, and rushed to the door.

The emergency lights had been switched on, and they could see fairly well by the dim illumination. They hurried into the pilot house at the bow. Edwards was struggling with the controls, pale but determined.

"There's something wrong with the steering apparatus we've run into a group of tiny meteorites, but, thank God, they didn't hit hard enough to penetrate the shell. The other ships seem to be in good shape; they're standing by a few hundred miles away, for I've signaled them not to get themselves tangled up with this shower."

At that moment a breathless tube-man came running in.

"Report for you, sir, from the tube-room. Someone tampered with the timing device that controls the feeding of the charges. We can have it repaired in a few hours."

"Good," snapped Edwards. "Give me all the power you can from the emergency tubes, and keep the main stern tubes going full." Turning to Holden, he continued, "I'll try to steer out of this shower by means of the deceleration tubes, but I don't dare use up too much of their power, and they can't be recharged until after we land."

"Captain Linet," Holden ordered, "start a search of the ship. Go over every man's room first, and pay especial attention to their baggage. Read all the private papers you can find, and see if you can't get some clue as to why all this is being done. By the way, do we have any arms on board?"

Linet smiled. "While your orders didn't cover that matter, sir, I took the liberty to bring with me a very complete arsenal of small arms, and three of the newly developed rapid-fire disintegrators, using your hexoxen as the material for the bullets. Very effective, I may add."

"Fine. As soon as a man is searched, and has been entirely cleared of all shadow of suspicion, arm him."

Erickson departed with Captain Linet, and Holden remained in the pilot room, helping Edwards work the ship onward. After about an hour and a half, they had reached an area free from meteorites of dangerous size.

"I think I can handle her myself, now. Thanks very much," Edwards said, and Holden departed to do a little investigating on his own.

In the tube-room at the stern, he found Linet. The doughty Captain had evidently been giving the men a thorough raking over, for they were all looking slightly sheepish, as men do when they have had to reveal the most intimate details of their lives.

"All in shape here," Linet reported. "Five of the men I know best are searching the living quarters, under command of Professor Erickson. If you will come with me now, we will go to the observation room, where the rest of the men are loafing while off duty."

As they passed down the central hall in the section where the cabins were located, a man ran out from a side passage, saw them, and turned at full speed for the bow.

"Stop him," came a shout. Holden recognized the voice as Erickson's. The man heard it, too, for he whirled in his tracks, whipped an old-fashioned automatic pistol from his pocket, leveled it at Holden, and took careful aim. The fraction of a second during which his eye rested along the sights was his undoing.

Captain Linet's hand, hidden under the loose jacket he was wearing, pressed the release on his short-range ray pistol, a light bluish streak touched the man's breast, and he fell forward, his heart literally shattered by the energy of the ray.

Holden reached him first, and rolled him over. His face was faintly familiar, and doubt changed to recognition as Captain Linet exclaimed, "It's Chambers, a former petty officer on my airliner."

It was the man who had come up to the Captain while Holden and Erickson were conversing with him on the bridge.

"What on earth could the man have been up to? He must have been mad to attack me on this ship, with no chance of escape," exclaimed Holden. "Do you know anything of his record, Captain?"

"Nothing whatsoever, except that he seemed honest enough, and hard working. I was the one responsible for his presence on board here, as he had mentioned some knowledge of interplanetary travel, and we needed men."

Erickson had come up by that time.

"We found nothing in this man's cabin except some tools that he had evidently stolen from the machine shop, and a code book of the type used by commercial companies for interplanetary messages. He entered the room while we were searching it, and bolted when he saw us."

The thing was puzzling, but most of the men on board accepted the explanation that the man was mad, and had for some reason resorted to desperate measures to assure the safety of the moon.

"You know," explained Captain Linet, "back a few hundred years ago, there was the expression 'moonstruck' applied to people who were mentally deranged."

At any rate, the incident was closed, as no one could be found who might possibly have been an accomplice. Minor damage caused by the cloud of meteorites was repaired, and the three ships swung in close together, heading for the satellite which they were commissioned to destroy.

The men spent as much time as they could in their bunks, for there was hard dangerous work ahead of them. Huge cartridges had to be filled with hexoxen, caps of Europium placed on top, and adjustments made so that, after a certain time had elapsed, the catalyst would come into contact with the hexoxen, causing a reaction to take place which would continue almost as long as there was solid material present to be vaporized. One slip of tired hands, one miscalculation and many men, perhaps the entire party, would suffer a terrible fate.

Holden was busy with one of the latest and best maps of the moon, looking for places where landing could be made, and charting the spots where the cartridges would be buried. The exact time for which every charge was to be set had to be worked out in advance.