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AERONAUTICS side and rear fins, and a rudder in the rear. The Von Zeppelin airship, owned by the German government, is the largest of its kind, the gas bag being 420 feet long and 40 feet in diameter, with a gas capacity of between 300,000 and 400,000 cubic feet. It has attained a speed of 33 miles an hour, has made a trip of 220 miles and back, and has stayed up for seven hours.

The value of the dirigible airship is in the ability it affords to pass over an enemy’s country and observe the disposition and movements of troops and the plans and character of defenses. The Hague conference in 1907 passed a rule forbidding the dropping of projectiles from balloons or aerial machines.

We pass now to the third and more hopeful method of aerial navigation. The problem here is to construct a machine which shall contain within itself a supply of energy not only sufficient to lift itself above the ground but also to propel itself through the air. The ablest students of this problem have abandoned all hopes of successfully imitating the bird: the model is too complicated. Accordingly, they have concentrated their study upon driving through the air at high speed a thin, light plane, having its forward edge higher than its rear edge, and supporting beneath it the engine which propels it.

If a railway car had open sides and a plane roof, sloping from the front to the rear, it is evident that the faster the car is driven forward the greater will be the tendency to lift off the roof of the car.

Imagine, now, that the car is very light but strong, that it contains a light but powerful engine, and that the light, sloping roof is strong enough to support the entire car and its contents; you will then have in mind the type of flying machine which was constructed by Maxim in England and improved by Langley in America.

Since the experiments of Maxim and Langley, which were not practically successful, the problem has received the continuous study and effort of inventors and scientists. The first really successful result was achieved by the Wright Brothers of Dayton, Ohio, who after years of study and experiment produced an aeroplane which in 1905, near Dayton, made many successful ascensions. In 1908, at Fort Myers, near Washington, D. C., and LeMans, France, they frequently remained in the air for over an hour, changing direction and ascending and lighting at will. The machine is a biplane, the sustaining surfaces of which are parallel, one above the other, about 40 feet by 7, and is driven by a propeller placed amidships. In front is a biplane horizontal rudder for regulating the flight up or down, and in the rear a vertical rudder for steering. It is started by running on a monorail until sufficient impetus is secured to permit it to rise unaided.

Since 1908 marked advance has been made in perfecting the construction of the aeroplane and in actual performances. In 1909 Orville Wright by a cross-country flight, carrying a passenger, met the last government test, and the Wright aeroplane was accepted for use of the signal corps of the army. They received $25,000 with a bonus of $5,000 for speed attained beyond 40 miles an hour. (See .)

The most important step in connection with aviation after the invention of the Wright Brothers, was the grant of an American patent in 1913 for a stabilizer of their invention for maintaining automatic control. To prevent the tipping of the wings by a sudden puff a pendulum is connected with a motor; while to prevent sudden swerving up or down, there is a horizontal rudder actuated by a small plane mounted at a different angle from the main aeroplane, so that whenever there is a sudden change in the position of the machine, the horizontal rudder is adjusted so as to restore it to the proper position, very much as a bird governs similar motions with its tail.

An interesting development of aeronautics is the hydroaeroplane which combines a flying machine with a boat. It skims through the water and lifts when the proper speed is reached.   (in plants). A form of chemotropism in which oxygen is the directive agent.  , a noted Athenian orator, the rival and opponent of Demosthenes. After a varied career, as an actor on the stage and a public speaker of great eloquence, he was exiled and settled in Rhodes. Here he founded a school of eloquence. Three of his orations have come down to us, perhaps the most famous being that Against Ctesiphon. He died in Samoa 314 B. C., at the age of 76.   (525–456 B. C.), the earliest of the great Attic tragedians. He was born at Eleusis, of a noble family, and took an honorable part in the Persian war. His first efforts at tragedy are said to have been suggested by the god Bacchus, who appeared to him while asleep in the fields. At the age of 41 he won his first prize in the dramatic contests popular among the Athenians, and during his life