The steering and control in the air are arranged in principle exactly as in a small aeroplane, but it was not an easy problem to arrange that this 14-ton boat could be handled by one man of only normal strength. To insure easy operation, each control surface was carefully balanced in accordance with experiments made in a wind-tunnel on a model of it. The operating cables were run through ball-bearing pulleys, and all avoidable friction eliminated. Finally, the entire craft was so balanced that the centre of gravity of all weights came at the resultant centre of lift of all lifting surfaces, and the tail surfaces so adjusted that the machine would be inherently stable in flight. As a result, the boat will fly herself and will continue on her course without the constant attention of the pilot. However, if he wishes to change course, a slight pressure of his controls is enough to swing the boat promptly. There is provision, however, for an assistant to the pilot to relieve him in rough air if he becomes fatigued, or wishes to leave his post to move about the boat. In the design of the metal fittings to reduce the amount of metal needed a special alloy steel of 150,000 pounds per square inch tensile strength was used. To increase bearing areas, bolts and pins are made of large diameter but hollow. A feature that is new in this boat is the use of welded aluminum tanks for gasoline. There are nine 200-gallon tanks made of sheet aluminum with welded seams. Each tank weighs but 70 pounds, or .35 pounds per gallon of contents, about one-half the weight of the usual sheet-steel or copper tank. Loaded, the machine weighs 28,000 pounds, and when empty, but including radiator, water, and fixed instruments and equipment, 15,874 pounds. The useful load available for crew, supplies, and fuel is, therefore, 12,126 pounds. This useful load may be put into fuel, freight, etc., in any proportion desired. For an endurance flight there would be a crew of 5 men (850 pounds), radio and radiotelephone (220 pounds), food and water, signal-lights, spare parts, and miscellaneous equipment (524 pounds), oil (750 pounds), gasoline, 9,650 pounds. This should suffice for a flight of 1,400 sea miles. The radio outfit is of sufficient power to communicate with ships 200 miles away. The radiotelephone would be used to talk to other planes in the formation or within 25 miles. The principal dimensions and characteristics of the NC type may be summarized as follows: Engines 4 Liberty Power 1,600 Wing span 126 upper—94 feet lower Length 68 feet 5½ inches Height 24 feet 5⅛ inches Weight, empty 15,874 lbs. Weight, loaded 28,000 lbs. Useful load 12,126 lbs. Gravity-tank 91 gals. capacity Fuel-tanks 1,800 gals. capacity Oil-tanks 160 gals. capacity FIRST AERIAL STOWAWAY