Mr. Orville Wright has clearly demonstrated this to be possible by his experiments lately made at Kitty Hawk, N. C., where he was able to soar for ten minutes over the summit of a sand dune, so delicately adjusting the surfaces of his glider to the up-trend of the wind that he was falling or descending at the same speed that the wind was rising, and thus he seemed to stand still over one spot on the ground. After increasing his descent and approaching the ground, he was able by the delicacy of adjustment of his controls to change the relation in such a manner that the wind rising overbalanced the descending of the machine and he was carried backward and upward to the crest of the hill again, where he remained for a short time before again gliding downward to the level ground below. In the same manner that a boat sails against the wind by the force of the wind blowing against the sail, which is placed at an angle to it and which resists sidewise motion by the pressure of the water against the hull of the boat, a glider with horizontal sails set at the proper angle will also sail into the wind which blows against its surfaces and which makes the path of least resistance a motion forward and slightly descending with relation to the direction of the wind, but which, in the case of an upward moving current of air, may be a path rising in respect to the ground. The development of skill in this art will come by practice, and young men will follow out the ideas and suggestions of the more experienced until we will have small, light, flexible machines with such sensitive control that, with small motors to enable them to rise or to get from one place to another, much as a bird flaps its wings when necessary to add a little to the power which it gets from the wind itself, or in rising from the ground, will be able to sail around and glide on the strength of the wind for hours at a time. The clever aviator or real birdman with his keen instinct cultivated to a state of perfection, fitted with polarising glasses possibly, may seek out and utilise the various powers that are present in the air; adjusting his wings so that he will be supported by the upward motion of the air itself where it exists, or, by turning on his motor, moving from one rising column of air to another, upon which he may hover and circle around, steering clear of all those other air lanes which are leading in some other direction. These glasses, by showing where the air waves are all of one direction, may reveal a current flowing in one way, while they may make great masses of air flowing in some other direction appear as of some other colour, say red, for instance; or, again, in another direction, all may look green, and it will only be necessary to keep where all is pure white.