American War Balloon.
Military balloons were used by the French again, however, during their war in Africa in 1830. The Austrians also used them in 1849, and it is said the Russians had them at the siege of Sebastopol in the Crimean War. A Montgolfier balloon was made use of by the French in 1862 at the battle of Solferino; and the Americans also employed balloons during the Civil War a year later. The American war balloons were comparatively small ones, inflated with hydrogen. The hydrogen was manufactured in the way already described, by pouring dilute sulphuric acid upon scrap-iron. For making the gas upon the field two large tanks of wood called “generators” were used. In these the water and scrap-iron were placed and the acid poured upon them, the gas produced being carried to the balloon through pipes, passing first through vessels filled with lime-water to cool and purify it. When on the march four waggons were sufficient to carry the whole apparatus. The inflation, which took some time, was made as close to the scene of action as was considered safe, and when the balloon was once full a party of men could easily tow it about to where it was needed.
But the time when the balloon was most largely and most usefully used in time of war was during the Siege of Paris. In the month of September 1870, during the Franco-Prussian War, Paris was closely invested by the Prussian forces, and for eighteen long weeks lay besieged and cut off from all the rest of the world. No communication with the city was possible either by road, river, rail, or telegraph, nor could the inhabitants convey tidings of their plight save by one means alone. Only the passage of the air was open to them.
Quite at the beginning of the siege it occurred to the Parisians that they might use balloons to escape from the beleaguered town, and pass over the heads of the enemy to safety beyond; and inquiry was at once made to discover what aeronautical resources were at their command.
It was soon found that with only one or two exceptions the balloons actually in existence within the walls were unserviceable or unsuitable for the work on hand, being mostly old ones which had been laid aside as worthless. One lucky discovery was, however, made. Two professional aeronauts, of well-proved experience and skill, were in Paris at the time. These were MM. Godard and Yon, both of whom had been in London only a short time before in connection with a huge captive balloon which was then being exhibited there. They at once received orders to establish two balloon factories, and begin making a large number of balloons as quickly as possible. For their workshops they were given the use of two great railway stations, then standing idle and deserted. No better places for the purpose could be imagined, for under the great glass roofs there was plenty of space, and the work went on apace.
As the balloons were intended to make only one journey each, plain white or coloured calico (of which there was plenty in the city), covered with quick-drying varnish, was considered good enough for their material. Hundreds of men and women were employed at the two factories; and altogether some sixty balloons were turned out during the siege. Their management was entrusted to sailors, who, of all men, seemed most fitted for the work. The only previous training that could be given them was to sling them up to the roof of the railway stations in a balloon car, and there make them go through the actions of throwing out ballast, dropping the anchor, and pulling the valve-line. This was, of course, very like learning to swim on dry land; nevertheless, these amateurs made, on the whole, very fair aeronauts.
But before the first of the new balloons was ready experiments were already being made with the few old balloons then in Paris. Two were moored captive at different ends of the town to act as observation stations from whence the enemy’s movements could be watched. Captive ascents were made in them every few hours. Meanwhile M. Duruof, a professional aeronaut, made his escape from the city in an old and unskyworthy balloon called “Le Neptune,” descending safely outside the enemy’s lines, while another equally successful voyage was made with two small balloons fastened together.
And then, as soon as the possibility of leaving Paris by this means was fully proved, an important new development arose. So far, as was shown, tidings of the besieged city could be conveyed to the outside world; but how was news from without to reach those imprisoned within? The problem was presently solved in a most ingenious way.
There was in Paris, when the siege commenced, a society or club of pigeon-fanciers who were specially interested in the breeding and training of “carrier” or “homing” pigeons. The leaders of this club now came forward and suggested to the authorities that, with the aid of the balloons, their birds might be turned to practical account as letter-carriers. The idea was at once taken up, and henceforward every balloon that sailed out of Paris contained not only letters and despatches, but also a number of properly trained pigeons, which, when liberated, would find their way back to their homes within the walls of the besieged city.
When the pigeons had been safely brought out of Paris, and fallen into friendly hands beyond the Prussian forces, there were attached to the tail feathers of each of them goose quills, about two inches long, fastened on by a silken thread or thin wire. Inside these were tiny scraps of photographic film, not much larger than postage stamps, upon which a large number of messages had been photographed by microscopic photography. So skilfully was this done that each scrap of film could contain 2500 messages of twenty words each. A bird might easily carry a dozen of these films, for the weight was always less than one gramme, or 15½ grains. One bird, in fact, arrived in Paris on the 3rd of February carrying eighteen films, containing altogether 40,000 messages. To avoid accidents, several copies of the same film were made, and attached to different birds. When any of the pigeons arrived in Paris their despatches were enlarged and thrown on a screen by a magic-lantern, then copied and sent to those for whom they were intended.