I think that the experiments which I made with an aeroplane only 8 inches wide will be found the most reliable. All the machinery was running smoothly, and the experiments were conducted with a considerable degree of care. In making any formula on the lifting effect of the aeroplane, it should be based on what was accomplished with the 8-inch plane. Only a few experiments were made to ascertain the relative value of planes of different widths. However, I think we must all admit that a wide plane is not as economical in power as a narrow one. In order to make this matter plain, suppose that we have one aeroplane placed at such an angle that it will lift 2 lbs. per square foot at a velocity of 40 miles an hour; it is very evident that the air just at the rear of this aeroplane would be moving downward at a velocity corresponding to the acceleration imparted to it by the plane. If we wish to obtain lifting effect on this air by another plane of exactly the same width, we shall have to increase its inclination in order to obtain the same lifting effect, and, still further, it will be necessary to use more power in proportion to the load lifted. If a third aeroplane is used, it must be placed at an angle that will impart additional acceleration to the air, and so on. Each plane that we add will have to be placed at a sharper angle, and the power required will be just in proportion to the average angle of all the planes. As the action of a wide aeroplane is identical with that of numerous narrow ones placed in close proximity to each other, it is very evident that a wide aeroplane cannot be as efficient in proportion to its width as a narrow one. I have thought the matter over, and I should say that the lifting effect of a flat aeroplane increases rather faster than the square root of its width. This will, at least, do for a working hypothesis. Every flying machine must have what we will call “a length of entering edge”--that is, the sum of entering edges of all the aeroplanes must bear a fixed relation to the load carried. If a machine is to have its lifting effect doubled, it is necessary to have the length of entering edge twice as long. This additional length may, of course, be obtained by superposed planes, but as we may assume that a large aeroplane will travel faster than a small one, increased velocity will compensate in some degree for the greater width of larger aeroplanes. By careful study of the experiments which I have made, I think it is quite safe to state that the lifting effect of well-made aeroplanes, if we do not take into consideration the resistance due to the framework holding them in position, increases as the square of their velocity. Double their speed and they give four times the lifting effect. The higher the speed, the smaller the angle of the plane, and the greater the lifting effect in proportion to the power employed. When we build a steamship, we know that its weight increases as the cube of