We shall not see the business man flying to his office in the city from his country estate--unless some landing-field is built on the lower end of Manhattan Island as has been proposed. The Chamber of Commerce of the State of New York has taken up the matter of legislation to make landing-fields possible, and it must go through. The business man ought, in the near future, to be able to use the airplane for quick trips to Albany. It would save hours over rail time, and here the airplane has a wonderful field of usefulness. Airplanes have made the trip from Washington to New York in very quick time, only to have to go on to Mineola to land on the airdrome there. It takes nearly an hour to come in from Mineola, but even at that the saving of time is still considerable. The speed and efficiency of airplane travel to and from New York and other cities is materially affected by the lack of landing-fields close to the business section of the city. There must be a large field, broad in every dimension, to permit the landing and taking-off of airplanes. A machine must get up flying speed running across the ground before it gets into the air. The flying speed varies with the type of machine, and it may be estimated that most machines take-off and land at a speed of from forty-five to sixty miles an hour. The air must be passing through their planes at this speed before they will begin to fly, and it takes a little run to get up flying speed. Similarly, when an airplane lands, it must lose its flying speed gradually. It may glide to within a few feet of the ground, and then "flatten out" just off the ground and run along until it loses its speed, the air no longer passes over its planes fast enough to support it, and it drops to the ground. Such are the limitations which the necessity for speed in airplane flight imposes. Compare the paper dart flying through the air. As long as it moves quickly it will fly. Or a kite, that will fly when the wind is strong enough. The airplane creates its own wind to support itself. There are four forces acting on an airplane in flight, and they must be properly overcome and balanced. There is lift, the upward force exerted on the planes by the passage of air over their surfaces; and drift, the resistance to the passing of an airplane, the retarding force acting opposite to the direction of motion. Then thrust, the forward effort of a machine exerted by a propeller pushing or pulling. And finally gravity. The primary conditions of flight are that lift made by the planes shall be equal to the force of gravity, and that the forward thrust must be equal to the drift. At that point a machine will sustain flight--a fairly simple thing on paper. But the times that machines have stalled in the air, with their motors full on because their pilots have failed to sustain flight, have let the force of gravity overcome lift, are too numerous to mention.