"For example," continued Carthoris, "I have an all-night trip before me, as to-night. I set the pointer here upon the right-hand dial which represents the eastern hemisphere of Barsoom, so that the point rests upon the exact latitude and longitude of Helium. Then Istart the engine, roll up in my sleeping silks and furs, and with lights burning, race through the air toward Helium, confident that at the appointed hour I shall drop gently toward the landing-stage upon my own palace, whether I am still asleep or no.""Provided," suggested Thuvan Dihn, "you do not chance to collide with some other night wanderer in the meanwhile."Carthoris smiled. "No danger of that," he replied.
"See here," and he indicated a device at the right of the destination compass. "This is my `obstruction evader,' as I call it. This visible device is the switch which throws the mechanism on or off. The instrument itself is below deck, geared both to the steering apparatus and the control levers.
"It is quite simple, being nothing more than a radium generator diffusing radio-activity in all directions to a distance of a hundred yards or so from the flier. Should this enveloping force be interrupted in any direction a delicate instrument immediately apprehends the irregularity, at the same time imparting an impulse to a magnetic device which in turn actuates the steering mechanism, diverting the bow of the flier away from the obstacle until the craft's radio-activity sphere is no longer in contact with the obstruction, then she falls once more into her normal course. Should the disturbance approach from the rear, as in case of a faster-moving craft overhauling me, the mechanism actuates the speed control as well as the steering gear, and the flier shoots ahead and either up or down, as the oncoming vessel is upon a lower or higher plane than herself.
"In aggravated cases, that is when the obstructions are many, or of such a nature as to deflect the bow more than forty-five degrees in any direction, or when the craft has reached its destination and dropped to within a hundred yards of the ground, the mechanism brings her to a full stop, at the same time sounding a loud alarm which will instantly awaken the pilot. You see I have anticipated almost every contingency."Thuvan Dihn smiled his appreciation of the marvellous device.
The forward servant pushed almost to the flier's side.
His eyes were narrowed to slits.
"All but one," he said.
The nobles looked at him in astonishment, and one of them grasped the fellow none too gently by the shoulder to push him back to his proper place.
Carthoris raised his hand.
"Wait," he urged. "Let us hear what the man has to say--no creation of mortal mind is perfect. Perchance he has detected a weakness that it will be well to know at once. Come, my good fellow, and what may be the one contingency I have overlooked?"As he spoke Carthoris observed the servant closely for the first time. He saw a man of giant stature and handsome, as are all those of the race of Martian red men; but the fellow's lips were thin and cruel, and across one cheek was the faint, white line of a sword-cut from the right temple to the corner of the mouth.
"Come," urged the Prince of Helium. "Speak!"The man hesitated. It was evident that he regretted the temerity that had made him the centre of interested observation. But at last, seeing no alternative, he spoke.
"It might be tampered with," he said, "by an enemy."Carthoris drew a small key from his leathern pocket-pouch.
"Look at this," he said, handing it to the man. "If you know aught of locks, you will know that the mechanism which this unlooses is beyond the cunning of a picker of locks.
It guards the vitals of the instrument from crafty tampering.
Without it an enemy must half wreck the device to reach its heart, leaving his handiwork apparent to the most casual observer."The servant took the key, glanced at it shrewdly, and then as he made to return it to Carthoris dropped it upon the marble flagging. Turning to look for it he planted the sole of his sandal full upon the glittering object. For an instant he bore all his weight upon the foot that covered the key, then he stepped back and with an exclamation as of pleasure that he had found it, stooped, recovered it, and returned it to the Heliumite. Then he dropped back to his station behind the nobles and was forgotten.
A moment later Carthoris had made his adieux to Thuvan Dihn and his nobles, and with lights twinkling had risen into the star-shot void of the Martian night.