They fashioned their gliders of two parallel main planes like those of Octave Chanute. The width, length, distance between planes, rudders, auxiliary planes and their placing were all problems for the most careful study. It was very discouraging work, for no big thing comes easily. As their experiments proceeded they said they found one rule after another incorrect, and they finally discarded most of the books the scientists had written. Then with characteristic patience they started in to work out the problem from first principles. "We had taken aeronautics merely as a sport," they wrote later. "We reluctantly entered upon the scientific side of it. But we soon found the work so fascinating that we were drawn into it deeper and deeper." The Wrights knew that an oblong plane--that is, a long narrow one--driven through the air broadside first is more evenly supported by the air than would be a plane of the same area but square in shape. The reason for this is that the air gives the greatest amount of support to a plane at the entering edge, as it is called in aviation--that is, the edge where it is advancing into the air. A little way from the edge the air begins to slip off at the back and sides and the support decreases. Thus, it will be seen that if the rear surface, which gives little support because the air slips away from under it, is put at the sides, giving the plane a greater spread from tip to tip and not so much depth from front to rear, the plane is more efficient--that is, more stable, less subject to drifting, and better able to meet the varying wind currents. Scientists call this proportion of the spread to the depth the aspect ratio of planes. For instance, if a plane has a spread of 30 feet and a depth of 6 feet it is said to have an aspect ratio of _5_. This is a very important consideration in the designing of an aeroplane, because aspect ratio is a factor in the speed. In general, high speed machines have a smaller aspect ratio than slower ones. The aspect ratio also has an important bearing on the general efficiency of an aeroplane, but the lifting power of a plane is figured as proportionate to its total area. In order to hold the air, and keep its supporting influence, aviators have tried methods of enclosing their planes like box kites, and putting edges on the under sides. This latter was found a mistake because the edge tended to decrease the speed of the flier and did more harm than the good obtained through keeping the air.