JACQUARD ATTACHMENT FOR LOOMS
SEVEN MILES ABOVE THE EARTH
The greatest altitude ever attained by a balloon has been claimed for Glaisher and Coxwell, who in 1862 went up to a height of seven miles. Both men were overcome by the extreme rarity of the atmosphere. Coxwell, however, although nearly paralyzed and unable to move his arms, succeeded in seizing the safety valve rope in his teeth and pulled it before he lost consciousness. The balloon was then at an altitude of 29,000 feet and rising at the rate of 1,000 feet per minute. Thirteen minutes elapsed before he regained his senses, and then the balloon was falling at the rate of 2,000 feet per minute. From the data furnished, it has been estimated that an altitude of 37,000 feet was reached. While there has been much dispute as to the authenticity of this record, the altitude of 35,100 feet established in 1901 by Professor Berson and Dr. Suring in the German balloon Preussen, probably represents a higher ascent than that of Glaisher’s balloon.
The new system of aerial transportation proved very useful in the nineteenth century. During the siege of Paris, in 1870-1871, sixty-six balloons arose out of the beleaguered city, and all but seven made their escape in safety. In our own Civil War captive balloons were first used to direct the fire of artillery. It was in one of these balloons that Friedrich von Zeppelin, who was a German military attaché with the Union forces, made his first aerial ascent. He was so impressed with the advantages of military observation from such a lofty aerie that he became from that moment an aeronautical enthusiast, and on his return to Germany urged upon the military authorities the importance of the balloon in war. It was then that he began his aeronautic studies and experiments which culminated in the construction of the gigantic ships of the air with which Germany undertook to carry the terror of war into England.
KITE BALLOONS
In the World War captive balloons were extensively used by both sides, an important development being the kite balloon. The common spherical captive balloon is very unsteady except in perfectly still air. It bobs around and swings and turns, making an unfavorable base for careful observation. In heavy winds it is liable to be dashed to earth by sudden gusts. The kite balloon is held up not only by its own buoyancy, but also by the wind in the same way that a kite is supported. The bag is elongated (sausage-shaped) and is fastened to the anchor line in such a way that it is tilted like a kite. To assist in holding it in this position the balloon is ballasted at the after end and the ballast, if you please, is air. A big air-filled bag hangs from the stern of the balloon and serves as a rudder while two other horizontal bags serve as stabilizing fins.
SELF-PROPELLED BALLOONS
No sooner had the Montgolfier brothers proved that it was possible to rise off the earth upon a bubble of hot air, than inventors began to devise schemes of propelling the bubble and controlling its course. The first dirigible balloon was built in 1784 and, strangely enough, oars were used to propel it. The balloon had a fish-shaped body, just like that of modern airships, and the bag was kept inflated by means of air as it is to-day. It was realized even at that early date that the envelope must retain its shape if it is to plow through the air with a minimum of friction. As the gas would gradually leak out of the envelope the bag would become flabby and present a crumpled bow to the ocean of the air and, to overcome this, a double envelope was provided and air was introduced between the inner and outer skin. Means were provided for pumping air in as the gas slowly escaped, thus keeping the envelope fully inflated. As the air was pumped in sand ballast was thrown overboard so that the buoyancy of the airship was not impaired. To-day air is used to keep gas envelopes inflated, but instead of placing the air in an outside envelope it is introduced into a small bag inside called a “ballonet.”
From time to time other means of propulsion were proposed and tried. In 1852 Henri Giffard, who is known as the Fulton of aerial navigation, built and operated a dirigible driven by a steam engine, which he hung at a considerable distance below the gas bag, so that the fire box would not be liable to ignite the highly inflammable gas. A draft was maintained in the fire box as it is in a locomotive by letting the steam discharge into the smoke stack, but in this case the stack was inverted and the smoke and gases were blown downward and away from the coal gas with which the balloon was inflated. The danger of fire and the difficulty of building a power plant light enough to be carried aloft and powerful enough to give the craft any material headway were the chief obstacles that had to be overcome. At the close of the nineteenth century, Santos Dumont, a Brazilian inventor, built a balloon that was driven by a gasoline engine. Despite the apprehension of other aeronauts this machine proved an unqualified success. Two years later, in 1900, Count Zeppelin introduced the rigid dirigible, which to-day is the standard for large airships.