“A few inventors tried to solve the flying problem with motor-driven balloons such as the German Zeppelin. But most attention was given to heavier-than-air machines known as aeroplanes. Aeroplanes are called heavier-than-air to distinguish them from balloons, which, being inflated with gas, are lighter than air. There were many discouraging years of hard thought and labor before success came. Finally, in 1905, two American brothers, Wilbur and Orville Wright, invented the first successful flying machine; and in a series of marvelous flights showed that Man had, at last, rivaled the birds. [Illustration] “Numerous inventions have made man almost the equal of the birds in the air. Flying has been made nearly as safe as riding on horseback or in an automobile. The aeroplane is now a necessity in times of war and peace. Its startling deeds will be the subject of the story I’m about to tell. “Of course, you want to know something about the man who runs an aeroplane,” said Uncle Sam. “Indeed, we do,” replied both boys at the same time. [Illustration: THE AEROPLANE IS A NECESSITY IN TIMES OF WAR AND PEACE] [Illustration: SOME TYPES OF AMERICAN AND FOREIGN AEROPLANES] [Illustration] [Illustration: GROUP OF FRENCH AVIATORS] “Now,” continued Uncle Sam, “to become a military aviator a man must, first of all, have a strong, healthy body, a quick, active mind, and iron nerves. There are many good aviators that wouldn’t be good _military_ aviators, because the strain of war would prove too much for them. If a man is just right in body and mind, they send him to an aviation training camp where he is taught to fly. [Illustration: LEARNING TO FLY BY WATCHING THE EXPERT AVIATOR] “At the training camp he is instructed in the care of an aeroplane and its powerful motor. He goes up in the air a number of times with an expert aviator. By constantly watching the expert, he learns to fly. Then he learns many dazzling stunts—to loop-the-loop, make figure eights, fly upside down, and other dangerous maneuvers. “After the new aviator knows how to care for an aeroplane and fly perfectly, he is taught wireless telegraphy, and shown how to take aerial photographs, fire machine guns and drop bombs. As soon as he learns all these things, he’s a full-fledged aviator, and ready to go into active service for his country.” Tom and Jack had their eyes wide open in wonder as Uncle Sam continued: “Ordinary flying, as I told you boys before, is now almost as safe as riding on horseback or in an auto. But, in time of war, running a military aeroplane is the riskiest work in the world. When I tell you of the marvelous, death-defying deeds military aviators have done, I doubt if you will believe me. Yet everything is absolutely true. [Illustration: AEROPLANE DIRECTING ARTILLERY FIRE] [Illustration: AVIATORS TAKING PHOTOGRAPHS]