Inventions of the Great War

at Sail

alloons were to be connected by telegraph wires with the ground, so that they could direct the artillery fire. The idea was so novel to the military authorities of that day that it was not rec

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that was forced to c

awn south of the White House to watch the demonstration. In order to test him, Mr. Lincoln took off his hat, waved his handkerchief, and made other signals. Lowe observed each act through his field-glasses and reported it to the President by telegraph. Mr. Lincoln was so impressed by the demonstrat

"Scientifi

ed from a Zeppelin sa

ged military authorities to provide themselves with captive balloons. This young officer was Count Ferdinand von Zeppelin, who was destined later to become the most famous a?ronautic authority in the world and who lived to see Germany equipped with a fleet of balloons which were self-propelling and could travel over land and sea to spread German frightfulness into England. He also lived to see the virtual failure of this type of war-machin

GHT OF

s less than the air it displaces. It is hard to think of air as having weight, but if we weigh air, hydrogen, coal-gas, or any other gas, in a vacuum, it will tip the scales just as a solid would. A thousand cubic feet of air weighs 80 pounds. In other words, the air in a room ten feet square with a ceiling ten feet high, weighs just about 80 pounds. The same amount of coal-gas weighed in a vacuum would register only 40 pounds; while an equal volume of hydrogen would weigh only 5? pounds. But when we speak of volumes of gas we must remember that gas, unlike a liquid or a solid, can be compressed or expanded to almost any dimensions. For instance, we could easi

bag so that the gas will not diffuse into the air and mix with it, we shall have a balloon which would float in air provided the bag and the hydrogen it contains do not weigh more than eighty pounds. As we rise from the surface of the earth, the a

sun beats upon a balloon, it heats the hydrogen, expanding it and making it relatively lighter, and if there is no room for this expansion to take place in the bag, the bag will burst. For this reason, a big safety-valve must be provided and the ordinar

ount of gas, until he reaches a level at which he finds a breeze blowing in the desired direction. Such was the airship of Civil War times, but for military purposes it was not advisable to use free balloons, because of the difficulty of controlling them. T

FAILURES AN

er failure. He believed in big machines and the loss of one of his airships meant the waste of a large sum of money, but he persisted, even though he spent all his fortune, and had to go heavily in debt. Every one thought him a crank until he built his third airsh

r another. Evidently the building of Zeppelin airships was not a paying undertaking, although they were used to carry p

that could sail through the air, particularly after the airplane was invented, and so it happened that when the war started the French were devoting virtually all their energies to the constructio

IGID, AND FLE

rigid keel or body. The British clung to the idea of an entirely flexible balloon and they suspended their car from the gas-bag without any rigid framework to hold the gas-bag in shape. In every case, the balloons were kept taut or distended by means of air-bags or ballonets. These air-bags were placed inside the gas

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ible built along th

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rs or "power eggs" o

ugh buoyancy in the rest of the gas-bags to hold up the airship. As the Zeppelins were enormous structures, the framework had to be made strong and light, and it was built up of a latticework of aluminum alloy. Aluminum itself was not strong enough for the purpose, but a mixture of al

Internationa

Dirigible) starting for Newfound

ed a large hydrogen gas-bag. A super-Zeppelin, as the latest type is called, was about seventy-five feet in diameter and seven hundred and sixty feet long, or almost as long as three New York street blocks. In its gas-bags it carri

CLEAR OF THE INF

means of large steering rudders and horizontal rudders, the machine could be forced to dive or rise or turn in either direction laterally. The pilot of the Zeppelin had an elaborate operating-compartment from which he could control the rudders, and he also had control of the valves in the ballonets so that by the touch of a button he could regulate the pressure of gas in any part of the dirigible. There were nineteen men in the

to fight off airplanes. Gasolene was stored in tanks which were placed in various parts of the machine, any one of which could feed one or all of the engines, and they were so arranged that they could be thrown overboard when the gasolene was used up, so as to lighten the load of the Zeppelin. Water ballast was used instead of sand,

from Kade

Tail of a

Photograph from

Basket of an Ob

IN'S TINY

the use of search-lights at the landing-fields. The airplane would signal its desire to land and the search-lights would point out the proper landing-field for it. So that after the first few months of the war Zeppelins were subjected to the danger of airplane attack. Of course,

h by Kade

mounted on a Gun Turret

nt and this would produce an explosive mixture which needed but the touch of fire to set it off. The Zeppelin was provided with a ventilating-system to carry off these explosive gases, but they could never be disposed of very effectively, and, as a consequence, a number of Zeppelins were destroyed by the tiny antagonists that were sent up by the British and the French. To fight off these assailants the Germans provided their Zeppelins with guns which would fire shrapnel shell. It is difficult for a Zeppelin to use machine-guns against an air

OBSERVER BEL

indows forward and there was plenty of room in it for a man to lie at full length and make observations of things below. The car with its observer could be lowered a few thousand feet below the Zeppelin, so that the observer could watch

vessel because it was so very costly to construct and operate and could so easily be destroye

y building machines patterned after the Zeppelin, but even larger, and expected to use them for bombing-excursions over Germany. This astonishin

GAS THAT W

flammable airship. Could we not furnish a substitute for hydrogen that would not burn? It was suggested to us that helium would do i

brilliant halo all around the black disk of the moon. Long ago, astronomers analyzed this flaming atmosphere with the spectroscope, and by the different bands of light that appeared they were able to determine wh

d sensation, but the general public attached no special importance to the gas itself. It proved to be a very light substance, next to hydrogen the lightest of gases, and for years it resisted all attempts at liquefaction. Only when Onnes, the Dutch scientist, succeeded in getting it down to a temperature of 450 degrees below zero, Fahrenheit, did the gas yi

the United States had more than five cubic feet of it and its price ranged from $1,500 to $6,000 per cubic foot. At the lowest price it wo

HEMISTS TO

old than any other and this fact gave the clue to its recovery from natural gas. The latter was frozen and one after another the different elements condensed into liquid, until finally only helium was left. This sounds simple, but it is a difficult matter to get such low temperature as that on a large scale and do it economically. To be of any real service in a?ronautics helium would have to be reduced in cost from fifteen hundred dollars to less than ten cents per cu

d and sea. For, even in time of peace, sailing under millions of cubic feet of hydrogen is a serious matter. Although no incendiary bullets are to be feared, there is always the danger of setting fire to the gas within the exhaus

f fire than they would have on shipboard. Wonderful possibilities have been opened by the production of helium on a large and economical scale, and the airship seems destined to play an important part in transportation very soon. As this book is going to press, we learn of enormous dirigibles about to be built in England for passenger service, which will have half again as