Begin with a very simple model. You will soon learn the trick of judging the size of the supporting surfaces and the spacing. The Antoinette aeroplane is probably the easiest one to imitate. From a sheet of ordinary writing paper, cardboard or fine wood, cut the form indicated. If the paper be rather heavy, it may be made six inches in length. By folding the paper and making one cutting, it will be found much easier to make the wings even and symmetrical. The two sides should be fixed at a broad dihedral angle. To keep the little glider on an even keel you will need to add a weight to the front. A large pin or paper clip will answer. Launch the glider by holding it horizontally and throwing slightly forward. If it darts downward, lighten the ballast. If it falls backward, "sitting on its tail," add more weight at the front or bend the tail up. Your glider will, of course, travel to the ground along the line of least resistance, and the trick is to adjust the center of gravity and center of pressure that this descent may be as gradual as possible. The center of gravity should come a little in front of the center of pressure. The gliding angle, as it is called, or the angle between the course of the model in flight with the ground should be about one in twelve. In other words, the glider descends one foot for every twelve feet it travels forward. Practically all the famous monoplanes may be reproduced in this way. A variety of gliders may be made in a general arrow form. These arrows, or darts, as they are called, may be made about a foot in length and three or four inches in width. The horizontal surface, it should be borne in mind, is the supporting surface, while the vertical surface gives the flight direction. These gliders will also require weighting at the forward end. They should be thrown forward with rather more force than in the case of the Antoinette. The biplanes such as the Wright and Curtiss aeroplanes may be reproduced very easily in paper. They fly best when made about six inches in length. Cut the two sheets of paper for the main planes one inch by six inches and round off the corners on one side. Two similar sheets, one by three inches, will be required for the smaller plane in the rear. The planes are held in position by a series of paper struts, or toothpicks, and should be separated by a distance equal to their width, in this case one inch. Cut the slips of paper to form the struts one and one-half inches in length and bend over the corners at right angles, one-quarter of an inch from either end. These should be pasted in position, always keeping the edge of the struts lengthwise so that they will offer the least resistance in flight.