It was this type of motor with which my scout flier was equipped--a seemingly fuelless motor, since it derived its invisible and imponderable energy from the inexhaustible and illimitable magnetic field of the planet. There are certain basic features of the new motor that only the inventor and the government of Helium are fully conversant with and these are most jealously guarded. The propeller shaft, which extends well within the hull of the flier, is constructed of numerous lateral segments insulated from one another. Around this shaft and supporting it is a series of armature-like bearings, through the center of which it passes. These are connected in series with a device called an accumulator through which the planet's magnetic energy is directed to the peculiar armatures which encircle the propeller shaft. Speed is controlled by increasing or diminishing the number of armature bearings in series with the accumulator--all of which is simply accomplished by a lever which the pilot moves from his position on deck where he ordinarily lies upon his stomach, his safety belt snapped to heavy rings in the deck. The limit of speed, the inventor claims, is dependent solely upon the ratio of strength to weight in the construction of the hull. My one-man scout flier easily attains a speed of two thousand haads per zode (_Note: Approximately three hundred miles per hour_), nor could it have withstood the tremendous strain of a more powerful motor, though it would have been easy to have increased both the power of one and the speed of the other by the simple expedient of a longer propeller shaft carrying an additional number of armature bearings. In experimenting with the new motor at Hastor last year, an attempt was made to drive a scout flier at the exceptional speed of thirty-three hundred haads per zode (_Note: Approximately five hundred miles per hour; a haad being 1949.0592 earth feet and a zode 2.462 earth hours_), but before the ship had attained a speed of three thousand haads per zode it was torn to pieces by its own motor. Now we are trying to attain the greatest strength with the minimum of weight and as our engineers succeed we shall see speed increased until, I am sure, we shall easily attain to seven thousand haads per zode (_Note: Over one thousand miles per hour_), for there seems to be no limit to the power of these marvelous motors. Little less marvelous is the destination control compass of Carthoris of Helium. Set your pointer upon any spot on either hemisphere; open your throttle and then lie down and go to sleep if you will. Your ship will carry you to your destination, drop within a hundred yards or so of the ground and stop, while an alarm awakens you. It is really a very simple device, but I believe that John Carter has fully described it in one of his numerous manuscripts.