Still holding the cylinder in his hand, Phor Tak stepped to a shallow cabinet against the wall and opening it revealed an elaborate equipment of switches, levers and push buttons. "Now watch the miniature flier suspended from the track near the ceiling," he directed, at the same time closing a switch. Immediately the flier commenced to travel along the track at considerable speed. Now Phor Tak pressed a button upon the top of the cylinder, which immediately sped from his extended palm, turned quickly in the air and rushed straight for the speeding flier. Slowly the distance between the two closed; the cylinder, curving gradually into the line of flight of the flier, was now trailing directly behind it, its pointed nose but a few feet from the stern of the miniature ship. Then Phor Tak pulled a tiny lever upon his switchboard and the flier leaped forward at accelerated speed. Instantly the speed of the cylinder increased and I could see that it was gaining in velocity much more rapidly than the flier. Half way around the room again its nose struck the stem of the fleeing craft with sufficient severity to cause the ship to tremble from stem to stern; then the cylinder fell away and floated gently toward the floor. Phor Tak opened a switch that stopped the flier in its flight and then, running forward, caught the descending cylinder in his hand.

"This model," he explained, as he returned to where we stood, "is so constructed that when it makes contact with the flier it will float gently downward to the floor, but as you have doubtless fully realized ere this, the finished product in practical use will explode upon contact with the ship. Note these tiny buttons with which it is covered. When any one of these comes in contact with an object, the model stops and descends, whereas the full-sized device, properly equipped, will explode, absolutely demolishing whatever it may have come in contact with. As you are aware every substance in the universe has its own fixed vibratory rate. This mechanism can be so attuned as to be attracted by the vibratory rate of any substance. The model, for example, is attracted by the blue protective paint with which the flier is covered. Imagine a fleet of Jaharian warship moving majestically through the air in battle formation. From an enemy ship or from the ground and at a distance so far as to be unobservable by the ships of Jahar, I release as many of these devices as there are ships in the fleet, allowing a few moments to elapse between launchings. The first torpedo rushes toward the fleet and destroys the nearest ship. All the torpedoes in the rear, strung out in line, are attracted by the combined masses of all the blue protecting coverings of the entire fleet. The first ship is falling to the ground and though all of its paint may not have been destroyed, it has not the power to deflect any of the succeeding torpedoes, which one by one destroy the nearest of the remaining ships until the fleet has been absolutely erased. I have destroyed a great fleet without risking the life of a single man of my own following."

"But they will see the torpedoes coming," suggested Nur An, "and they will devise some defense. Even gunfire might stop many of them."

"Heigh-oo! But I have thought of that," cackled Phor Tak. He laid the torpedo upon a bench and opened another cabinet.

In this cabinet were a number of receptacles, some tightly sealed and others opened, revealing their contents which appeared to be different colored paints. From a number of these receptacles protruded the handles of paint brushes. One such handle, however, appeared to hang in midair, a few inches above one of the shelves, while just beneath it was a section of the rim of a receptacle that also appeared to be resting upon nothing. Phor Tak placed his open hand directly beneath this floating rim and when he removed his hand from the cabinet, the rim of the receptacle and the portion of the handle of the paint brush, floating just above it, followed, hovering just over his extended fingers, which were cupped in the position that they might assume were they holding a glass jar, such as would ordinarily have belonged to a rim like that which I could see floating about an inch above his fingers.

Going to the bench where he had laid the cylinder, Phor Tak went through the motions of setting a jar upon it, and, though there was no jar visible other than the floating rim, I distinctly heard a noise that was identical with the sound which the bottom of a glass jar would have made in coming in contact with the bench.

I can assure you that I was greatly mystified, but still more so by the events immediately following. Phor Tak seized the handle of the paint brush and made a pass a few inches above the metal torpedo. Instantly a portion of the torpedo, about an inch wide and three or four inches long, disappeared. Pass after pass he made until finally the whole surface of the torpedo had disappeared. Where it had rested the bench was empty. Phor Tak returned the handle of the paint brush to its floating position just above the floating jar rim and then he turned to us with an expression of child-like pride upon his face, as much to say, "Well, what do you think of that? Am I not wonderful?" And I was certainly forced to concede that it was wonderful and that I was entirely baffled and mystified by what I had seen.

"There, Nur An," exclaimed Phor Tak, "is the answer to your criticism of The Flying Death."

"I do not understand," said Nur An with a puzzled expression upon his face.

"Heigh-oo!" cried Phor Tak. "Have you not seen me render the device invisible?"

"But it is gone," said Nur An.

Phor Tak laughed his high cackling laugh. "It is still there," he said, "but you cannot see it. Here," and he took Nur An's hand and guided it toward the spot where the device had been.

I could see Nur An's fingers apparently feeling over the surface of something several inches above the top of the table. "By my first ancestor, it is still there!" he exclaimed.

"It is wonderful," I exclaimed. "You did not even touch it; you merely made passes above it with the handle of a paint brush and it disappeared."

"But I did touch it," insisted Phor Tak. "The brush was there, but you did not see it because it was covered by the substance which renders The Flying Death invisible. Notice this transparent glass receptacle in which I keep the compound of invisibility and all that you can see of it is that part of the rim which, by chance, has not been coated with the compound."

"Marvelous!" I exclaimed. "Even now, although I have witnessed it with my own eyes I can scarce conceive of the possibility of such a miracle."

"It is no miracle," said Phor Tak. "It is merely the application of scientific principles well known to me for hundreds of years. Nothing moves in straight lines; light, vision, electromagnetic forces follow lines that curve. The compound of invisibility merely bows outward the reflected light, which, entering our eyes and impinging upon our optic nerves, results in the phenomenon which we call vision, so that they pass around any object which is coated with the compound. When I first started to apply the compound to The Flying Death, your line of vision was deflected around the small portions so coated, but when I coated the entire surface of the torpedo, the curve of your vision passed completely around it on both sides so that you could plainly see the bench upon which it was resting precisely as though the device had not been there."

I was astounded at the apparent simplicity of the explanation, and, naturally, being a soldier, I saw the tremendous advantage that the possession of these two scientific secrets would impart to the nation which controlled them. For the safety; yes, for the very existence of Helium, I must possess them and if that were impossible, then Phor Tak must be destroyed before the secret of this infernal power could be passed on to any other nation. Perhaps I could so ingratiate myself with old Phor Tak as to be able to persuade him to turn these secrets over to Helium in return for Helium's assistance in the work of wreaking his vengeance upon Tul Axtar.