I shall spare the reader a recital of the tireless efforts, continuing through many almost sleepless weeks, whereby Andrew Hall obtained his clew to Dr. Syx’s method. It was manifest from the beginning that the agent concerned must be some form of etheric, or so-called electric, energy; but how to set it in operation was the problem. Finally he hit upon the apparatus for his initial experiments which I have already described.

“Recurring to what had been done more than half a century ago by Hertz, when he concentrated electric waves upon a focal point by means of a concave mirror,” said Hall, “I saw that the key I wanted lay in an extension of these experiments. At last I found that I could transform the energy of an engine into undulations of the ether, which, when they had been concentrated upon a metallic object, like a chunk of gold, imparted to it an intense charge of an apparently electric nature. Upon thus charging a metallic body enclosed in a vacuum, I observed that the energy imparted to it possessed the remarkable power of disrupting its atoms and projecting them off in straight lines, very much as occurs with a kathode in a Crookes’s tube. But—and this was of supreme importance—I found that the line of projection was directly towards the apparatus from which the impulse producing the charge had come. In other words, I could produce two poles between which a marvellous interaction occurred. My transformer, with its concentrating mirror, acted as one pole, from which energy was transferred to the other pole, and that other pole immediately flung off atoms of its own substance in the direction of the transformer. But these atoms were stopped by the glass wall of the vacuum tube; and when I tried the experiment with the metal removed from the vacuum, and surrounded with air, it failed utterly.

“This at first completely discouraged me, until I suddenly remembered that the moon is in a vacuum, the great vacuum of interplanetary space, and that it possesses no perceptible atmosphere of its own. At this a great light broke around me, and I shouted ‘Eureka!’ Without hesitation I constructed a transformer of great power, furnished with a large parabolic mirror to transmit the waves in parallel lines, erected the machinery and buildings here, and when all was ready for the final experiment I telegraphed for you.” Prepared by these explanations I was all on fire to see the thing tried. Hall was no less eager, and, calling in his two faithful assistants to make the final adjustments, he led the way into what he facetiously named “the lunar chamber.”

“If we fail,” he remarked with a smile that had an element of worriment in it, “it will become the ‘lunatic chamber’—but no danger of that. You observe this polished silver knob, supported by a metallic rod curved over at the top like a crane. That constitutes the pole from which I propose to transmit the energy to the moon, and upon which I expect the storm of atoms to be centred by reflection from the mirror at whose focus it is placed.”

“One moment,” I said. “Am I to understand that you think that the moon is a solid mass of artemisium, and that no matter where your radiant force strikes it a ‘kathodic pole’ will be formed there from which atoms will be projected to the earth?”

“No,” said Hall, “I must carefully choose the point on the lunar surface where to operate. But that will present no difficulty. I made up my mind as soon as I had penetrated Syx’s secret that he obtained the metal from those mystic white streaks which radiate from Tycho, and which have puzzled the astronomers ever since the invention of telescopes. I now believe those streaks to be composed of immense veins of the metal that Syx has most appropriately named artemisium, which you, of course, recognize as being derived from the name of the Greek goddess of the moon, Artemis, whom the Romans called Diana. But now to work!”

It was less than a day past the time of new moon, and the earth’s satellite was too near the sun to be visible in broad daylight. Accordingly, the mirror had to be directed by means of knowledge of the moon’s place in the sky. Driven by accurate clockwork, it could be depended upon to retain the proper direction when once set.

With breathless interest I watched the proceedings of my friend and his assistants. The strain upon the nerves of all of us was such as could not have been borne for many hours at a stretch. When everything had been adjusted to his satisfaction, Hall stepped back, not without betraying his excitement in flushed cheeks and flashing eyes, and pressed a lever. The powerful engine underneath the floor instantly responded. The experiment was begun.

“I have set it upon a point about a hundred miles north of Tycho, where the Yerkes photographs show a great abundance of the white substance,” said Hall.

Then we waited. A minute elapsed. A bird, fluttering in the opening above, for a second or two, wrenched our strained nerves. Hall’s face turned pale.

“They had better keep away from here,” he whispered, with a ghastly smile.

Two minutes! I could hear the beating of my heart. The engine shook the floor.

Three minutes! Hall’s face was wet with perspiration. The bird blundered in and startled us again.

Four minutes! We were like statues, with all eyes fixed on the polished ball of silver, which shone in the brilliant light concentrated upon it by the mirror.

Five minutes! The shining ball had become a confused blue, and I violently winked to clear my vision.

“At last! Thank God! Look! There it is!”

It was Hall who spoke, trembling like an aspen. The silver knob had changed color. What seemed a miniature rainbow surrounded it, with concentric circles of blinding brilliance.

Then something dropped flashing into an earthen dish set beneath the ball! Another glittering drop followed, and, at a shorter interval, another!

Almost before a word could be uttered the drops had coalesced and become a tiny stream, which, as it fell, twisted itself into a bright spiral, gleaming with a hundred shifting hues, and forming on the bottom of the dish a glowing, interlacing maze of viscid rings and circlets, which turned and twined about and over one another, until they had blended and settled into a button-shaped mass of hot metallic jelly. Hall snatched the dish away, and placed another in its stead.

“This will be about right for a watch charm when it cools,” he said, with a return of his customary self-command. “I promised you the first specimen. I’ll catch another for myself.”

“But can it be possible that we are not dreaming?” I exclaimed. “Do you really believe that this comes from the moon?”

“Just as surely as rain comes from the clouds,” cried Hall, with all his old impatience. “Haven’t I just showed you the whole process?”

“Then I congratulate you. You will be as rich as Dr. Syx.”

“Perhaps,” was the unperturbed reply, “but not until I have enlarged my apparatus. At present I shall hardly............