Great advances will be made in the art of aviation along the lines of training men in the art of handling an aeroplane. No opportunity is so good for this purpose as handling the machine as a glider with the motor shut off, or by practise with a regular gliding machine. Boys will naturally take to gliding, and as a glider was the first form of flying-machine and the easiest to build mechanically, there is every reason why sailing or soaring flights should be thoroughly mastered. The instinct which birds have which enables them to seek out and to utilise the rising currents of air in the wind and so to set and adjust their wings as to enable them to take advantage of these rising currents, is latent in the human mind and can be developed by practice to a point far exceeding that of birds, on account of man's superior intelligence. It is quite possible that some arrangement may be made by which an aviator can see the air and can prepare for or escape conditions that are not favourable to his manœuvres. It is clear that the wind gusts, swirls, and turbulences exist in the air, for they are quite evident when we watch a snowstorm and can see the snowflakes as they float, impelled now in one direction, now another, or as we see dry leaves carried about by a sudden gust of wind, or, even more clearly when over sandy plains we can see the great columns of dust ascending in the center of whirlwinds for hundreds of feet, carrying heavy particles to great heights. It is quite possible that birds can see the air itself by some arrangement of the lenses of their eyes which may either enable them to see the fine dust particles or to so polarise the light that the direction of its vibrations can be determined and the course of flight so changed that an air lane favourable to the path of the bird can be followed and by following out one stream lane among many, which has an upward trend sufficient to counteract the falling tendency, the bird can remain at an equal elevation.