This advice, coming from a man with such wide experience of the theory and practice of flying, should surely be heeded by all those who engage in deadly combat with the demons of the air. In the early days of aviation, pilots were unacquainted with the nature and method of approach of treacherous wind gusts; often when they were flying along in a steady, regular wind, one of these gusts would strike their craft on one side, and either overturn it or cause it to over-bank, so that it crashed to earth with a swift side-slip through the air. Happily the experience of those days, though purchased at the cost of many lives, has taught makers of air-craft to design their machines on more trustworthy lines. Pilots, too, have made a scientific study of air eddies, gusts, and so on, and the danger of flying in a strong or gusty wind is comparatively small. CHAPTER XLVII. Accidents and their Cause (Cont.) Many people still think that if the engine of an aeroplane should stop while the machine was in mid-air, a terrible disaster would happen. All petrol engines may be described as fickle in their behaviour, and so complicated is their structure that the best of them are given to stopping without any warning. Aeroplane engines are far superior in horse-power to those fitted to motorcars, and consequently their structure is more intricate. But if an airman's engine suddenly stopped there would be no reason whatever why he should tumble down head first and break his neck. Strange to say, too, the higher he was flying the safer he would be. All machines have what is called a GLIDING ANGLE. When the designer plans his machine he considers the distribution of the weight or the engine, pilot and passengers, of the petrol, aeronautical instruments, and planes, so that the aeroplane is built in such a manner that when the engine stops, and the nose of the machine is turned downwards, the aeroplane of its own accord takes up its gliding angle and glides to earth. Gliding angles vary in different machines. If the angle is one in twelve, this would mean that if the glide wave commenced at a height of 1 mile, and continued in a straight line, the pilot would come to earth 12 miles distant. We are all familiar with the gradients shown on railways. There we see displayed on short sign-posts such notices as "1 in 50", with the opposite arms of the post pointing upwards and downwards. This, of course, means that the slope of the railway at that particular place is 1 foot in a distance of 50 feet.