Patriotism has been the most powerful factor in developing aërial navigation. Montgolfier experimented with his paper balloons filled with heated air in the desire that his invention might be of use to France in her wars, and throughout the history of both balloons and flying machines we find that it has been the desire to employ them as instruments of war that has most fostered their progress.
Very soon after Charles invented the gas balloon the latter was pressed into military service for the very same purpose of reconnaissance for which airships and aëroplanes are now being used. At the time of the French revolutionary war an aëronautical school was founded at Meudon under the control of Guyton de Morveau, Coutelle, and Conté, and a company was formed called Aërostiers.
Captive balloons were used by the armies of the Sambre and Meuse, of the Rhine and Moselle. Just before the battle of Fleurus, 1794, two ascents were made, and the victory of the French was attributed to observations made by Coutelle. At that time several ascents were made from Liége with a spherical balloon and one of cylindrical shape. This latter appears to have anticipated the well-known German kite-balloon.
There is a tradition that in those early days of the balloon the French were possessed of a varnish which satisfactorily held the hydrogen gas, but that the secret was lost—a grave loss indeed, if the tradition has truth in it. The secret was never refound. A really gas-proof varnish is unknown.
In the course of the American Civil War of 1861 captive balloons were again employed with important results.
During the Franco-Prussian War of 1870 three captive balloons were installed in Paris, the “Nadar” on the Place St. Pierre; the “Neptune,” manned by Wilfred de Fonvielle, at the gasworks at Vaugirard; and the “Celeste” on the Boulevard des Italiens.
Thus long before the advent of airships and flying machines the use of altitude for military reconnaissance was realised. A great disadvantage of the captive balloon was its stationary nature. It was not prudent to ascend in it very close to the enemy, as there was not the same chance of escape as when the aërial observer is in mobile aircraft.
Though rifle fire has over and over again failed to bring down a captive balloon owing to the upward pressure of the hydrogen gas, still, artillery fire has been known to have very destructive effect.
Undoubtedly, the best use that has been made of the captive balloon was in the Boer War. The British observation balloon equipment, which under the unceasing labours of Colonel Templer had reached a state of considerable perfection, then proved to be highly efficient. But in the light of modern aëronautical progress its doings were merely the foreshadowings of the achievements the aviators in the present war are daily carrying out.
Perhaps the most important feature of the balloons in the South African War was the material of which they were made—gold-beaters’ skin. We are all more or less familiar with this substance, for we use it as a plaster when we cut our fingers. We should scarcely think that so apparently fragile a substance was strong enough to form the envelope of a balloon. It is, however, an admirable substance for the purpose on account of its lightness and capacity of holding the gas, and the desideratum of strength can be obtained by combining layer and layer of the substance to any desired thickness. By the use of gold-beaters’ skin it became possible to have much smaller balloons for a given lifting power than when varnished cambric or silk was employed. If made of the latter materials a captive observation balloon had to be at least 18,000 cubic feet to be of any service. Gold-beaters’ skin reduced the volume to 10,000 cubic feet, or even less.
The only disadvantage of gold-beaters’ skin for the envelope of balloons and airships appears to be its very great expense. This, in the case of a large airship, is formidable. It should be mentioned, however, that it has sometimes been used for the separate gas compartments which, as will be seen, are a feature of the Zeppelin airship.
As regards the actual achievements of the balloon in South Africa, one section did excellent work at Ladysmith. In the words of Colonel Templer, “it not only located all the Boer guns and their positions, but it also withdrew all the Boer fire on to the balloon. Several balloons were absolutely destroyed by shell fire.”
One of the balloons was burst at a height of 1,600 feet, and came down with a very quick run, but the staff officer in the car was unhurt. At Ladysmith, by means of the balloon, the British artillery fire was made decisive and accurate.
With General Buller at Colenso, and up the Tugela River, Captain Philips’ balloon section was very useful. Splendid work was done at Spion Kop. There the whole position was located and made out to be impregnable. It has been said that the British Army was then saved from falling into a death trap by the aërial reconnaissance. Captain Jones’ section went up with Lord Methuen on Modder River. His observations continued every day. It was considered there was not a single day that they were not of the utmost importance.
Again, Lord Kitchener and Lord Roberts used balloons. From the information they obtained from them they were enabled to march on to Paardeburg. At the latter place itself they were able to locate the whole position. Another section went to Kimberley and on to Mafeking. A very important observation was made at Fourteen Streams. There a balloon was used continuously for thirteen days without the gas being replenished. By its means the Boers were prevented from relieving Fourteen Streams.
It has been pointed out by Colonel Templer that one of the great difficulties connected with the use of the comparatively small balloons in the South African War was the heights the armies went over.
On the march to Pretoria there were hills 6,000 feet above the sea, and to make an observation from these hills it was necessary to go up 1,500 or 2,000 feet, so that the barometrical height was hard work on the buoyancy of the balloon, because the barometrical height then became 8,000 feet—the 6,000 feet altitude above the sea-level, and the 2,000 feet it was necessary to go over the hills—that was about all our balloons would do.
That was a disadvantage of the captive balloons which would not have been felt if the observers had been on aëroplanes!
Certainly, the excellent gas retaining power of gold-beaters’ skin was well put to the test in the South African War. The thirteen days’ work with one charge of gas mentioned above was a fair trial for a balloon of such comparatively small size; but Captain H. B. Jones gave a still more striking experience of the value of gold-beaters’ skin as a gas-holder. Speaking of the Bristol war balloon of 11,500 cubic feet capacity, he says:—
It was used at the engagements at Vet River and Land River, and arrived at Kroonstad on May 12th. The balloon was kept in a sheltered place near the river till we marched again, on May 22nd, and was not emptied till after we had crossed into the Transvaal at Vereeniging on May 27th. To keep a balloon going for thirteen days at one station is a good test; but in our case the Bristol was filled for twenty-two days, and did a march of 165 miles with the division.
The system of filling the balloons from steel cylinders in which the hydrogen gas had been compressed, so well exemplified in the Boer War, was a great improvement on the older methods of manufacturing the gas on the spot. Speed in filling balloons is a desideratum for their use in war. By the cylinder method, owing to the great pressure under which the gas escapes from the cylinder, the inflation of the observation balloons became a question of minutes instead of hours. The necessity of speed applies to the inflation of airships also.
Although the present volume is designed rather to speak of the aëronautical appliances of the present than those of the past, the above-mentioned facts concerning aërial reconnaissance in the Boer War have been included, as the value of the air scouts at the time was hardly known and appreciated by the general public, whose mind in those days was not constantly being directed to aërial matters as it is at the present time. The knowledge of what just a few well-contrived and well-utilised balloons could then do in the way of aërial scouting must lead to the thought how the Boer War might have been shortened had we then possessed the squadrons of fast-flying aëroplanes that are taking part in the present war. To know, indeed, what a very few aërial observers could do may enhance our estimation of the possibilities of the squadrons of the flying machines of the British and allied armies in the present war as they dart in search of information over the lines of the enemy.
In the course of some articles on the subject of the new arm of war, which contain many apt statements, Mr. F. W. Lanchester gives the opinion that the number of aërial machines engaged in the war is a negligible quantity. We might, indeed, well say the more the better, provided they are on the Allies’ side; but no aëronaut or aviator will allow the number is negligible. The writer compares the supposed number of aëroplanes the Germans possess with the cost equivalent of scouting cavalry. The comparison is not a happy one, on account of the tremendous advantage of altitude and, consequently, long range of vision possessed by the aërial scout. We have seen that in the Boer War one observer at Spion Kop from his height and super-sight saved the situation, and rescued our army from possible crushing disaster.
What might not even one shrewd British observer in a swift-moving modern aërial craft accomplish at a critical moment in the present conflict?