Problems, of course, have still to be solved; but none are insurmountable or so difficult as was the initial problem of making an aeroplane fly. Granted in due course that greater engine-power will be obtained, a problem outstanding concerns the wing area of a machine. For bearing a heavy load, when a craft is ascending and its speed is low, a large area is needed; but once the machine is well aloft, has ceased climbing, and is driving straight ahead, then its surface may be curtailed. A bullet rushes through the air by its own momentum; and with an aeroplane, as the speed grows high, only a small wing area is required. If a craft cannot curtail its surface, if it exposes when in full flight just as much area as it used when climbing, then the power of its motors is wasted and its efficiency impaired. What is wanted for high-speed flight, and what time and experiment should provide, is a method of reefing the planes of a machine. This would mean that, rising from the ground with its maximum surface, a machine would telescope its plane-ends gradually when a height had been reached, and continue so to reduce them until there came a limit of speed. In this way, and with multiple engines, a flying speed should be attained--even with large, heavily laden craft--of quite 200 miles an hour. Wind resistance, of course, will need to be considered, and “stream-lining” brought to its perfection. In the future, indeed, sloped delicately and trimmed to their finest lines, the hulls of high-speed craft should become pictures of grace.