The well-known aviator, Charles K. Hamilton, says:--“So far as the air currents are concerned, I rely entirely on instinctive action; but my ear is always on the alert. The danger signal of the aviator is when he hears his motor miss an explosion. Then he knows that trouble is in store. Sometimes he can speed up his engine, just as an automobile driver does, and get it to renew its normal action. But if he fails in this, and the motor stops, he must dip his deflecting planes, and try to negotiate a landing in open country. Sometimes there is no preliminary warning from the motor that it is going to cease working. That is the time when the aviator must be prepared to act quickly. Unless the deflecting planes are manipulated instantly, aviator and aeroplane will rapidly land a tangled mass on the ground.” [Illustration: Result of a failure to deflect the planes quickly enough when the engine stopped. The operator fortunately escaped with but a few bruises.] At the same time, Mr. Hamilton says: “Driving an aeroplane at a speed of 120 miles an hour is not nearly so difficult a task as driving an automobile 60 miles an hour. In running an automobile at high speed the driver must be on the job every second. Nothing but untiring vigilance can protect him from danger. There are turns in the road, bad stretches of pavement, and other like difficulties, and he can never tell at what moment he is to encounter some vehicle, perhaps travelling in the opposite direction. But with an aeroplane it is a different proposition. Once a man becomes accustomed to aeroplaning, it is a matter of unconscious attention.... He has no obstacles to encounter except cross-currents of air. Air and wind are much quicker than a man can think and put his thought into action. Unless experience has taught the aviator to maintain his equilibrium instinctively, he is sure to come to grief.” The Wright brothers spent years in learning the art of balancing in the air before they appeared in public as aviators. And their method of teaching pupils is evidence that they believe the only road to successful aviation is through progressive experience, leading up from the use of gliders for short flights to the actual machines with motors only after one has become an instinctive equilibrist.