Perfection of an automatic mechanical piloting mechanism for airplanes has been achieved after several years of experiment at the royal aircraft establishment of Farnborough. The apparatus has been successfully tried out on various types of planes--two-seater day bombers, large twin-engine night bombers and big flying boats. Its use as a second or relief pilot on long distance flights by Royal Air Force machines is now being considered. In every test the robot pilot has steered an accurate course for hours at a time and over distances up to 400 miles while human members of the crew have been concerned with other duties. The basis of the mechanical pilot is a gyroscope that controls pistons connected with the rudder and elevators of the plane. These pistons are actuated by compressed air. Once a course is set the robot pilot keeps the machine on that route and errors of even a fraction of a degree are instantly and automatically detected and corrected. All the human pilot has to do in a plane so equipped is to take off and land the machine. The Pilot's Assister is the official name of the new English device. It weighs about 120 pounds. Flights have been made with the mechanical pilot in all sorts of weather. In dense fog and clouds, when a human pilot would have found it almost impossible to maintain straight or level flight because of the absence of any visible horizon by which to steer, the mechanical pilot flew the plane with absolute accuracy. On one test flight the automatic pilot steered a dead true course from Farnborough in South England, to Newcastle, 270 miles farther north. The human pilot did not touch the controls until it was necessary to land the plane at the destination. Jetta of the Lowlands Conclusion _By Ray Cummings_ [Sidenote: Black-garbed figures move in ghastly greenness as the invisible flyer speeds on its business of ransom.] [Illustration: _Hans and I hauled out the heavy casket._] CHAPTER XV _In the Bandit Camp_ The dark cave, with its small spots of tube-light mounted upon movable tripods, was eery with grotesque swaying shadows. The bandit camp. Hidden down here in the depths of the Mid-Atlantic Lowlands. An inaccessible retreat, this cave in what once was the ocean floor. Only a few years ago water had been here, water black and cold and soundless. Tremendous pressure, with three thousand or more fathoms of the ocean above it. Fishes had roamed these passages, no doubt. Strange monsters of the deeps: sightless, or with eyes like phosphorescent torches. But the water was gone now. Blue ooze was caked upon the cave floor. Eroded walls; niches and tiny gullies; crevices and an arching dome high overhead. A fantastic cave--no one, seeing it as I saw it that morning at dawn, could have believed it was upon this earth. From where De Boer had put me--on the flat top of a small, butte-like dome near the upper end of the sloping cave floor--all the area of this strange bandit camp was visible to me.