Neither Mr. Glaisher or Mr. Coxwell were able to note the exact elevation when they were at their greatest height; but from several circumstances they were convinced that it must have been 36,000 or 37,000 feet, or fully seven miles high. Later aeronauts have been inclined to doubt if this surmise can be quite correct; but whether it is so or not is of no great moment, for this great balloon ascent will always stand unrivalled in the history of ballooning. Since that day nearly as great, or perhaps even greater, heights have been reached in balloons; but nowadays those who attempt to ascend to great elevations always provide themselves, before they start, with cylinders of compressed oxygen gas. Then when the atmosphere aloft becomes so thin and rare as to make breathing difficult, they begin to fill their lungs with the life-giving gas from the cylinders, and at once recover.
After this perilous voyage Glaisher and Coxwell made several other scientific balloon ascents. They met with various experiences. On one occasion, during a lofty ascent, they lost sight of the earth above the clouds for a while, but, the mist suddenly breaking, they found themselves on the point of drifting out to sea. Not a moment was to be lost, and both men hung on to the valve-line until it cut their hands. The result was a tremendously rapid descent. The balloon fell four and a quarter miles in less than a quarter of an hour, covering the last two miles in only four minutes. They reached earth close to the shore, and were fortunate to escape with only a few bruises, though all the instruments were once more broken in the shock.
Mr. Glaisher was able to make many interesting notes of the condition of the winds and clouds at high levels. He observed how frequently different currents of air are blowing aloft in different directions at the same time. These differing winds affect the shape of the clouds among which they blow. High above the ground he frequently met with a warm wind blowing constantly from the south-west; and he believed that it is largely due to this mild air-stream passing always overhead that England enjoys such much less rigorous winters than other countries that lie as far north of the equator. This mildness of our climate has long been attributed to the Gulf Stream, that warm current of the sea which sweeps up from the tropics past our shores. But it may well be that there is besides an “Aerial Gulf Stream,” as Mr. Glaisher calls it, blowing constantly above our heads, which also serves to warm the air, and make our winter climate mild and moist.
One fact these experiments seemed to establish was, that when rain is falling from an overcast sky, there is always a higher layer of clouds overhanging the lower stratum. Nothing surprised Mr. Glaisher more than the extreme rapidity with which the whole sky, up to a vast height, could fill up entirely with clouds at the approach of a storm. Another point noted was that, when a wind is blowing, the upper portion of the current always travels faster than that next the ground. This is due, of course, to the obstacles the wind meets as it sweeps over the earth, and which check its onward progress.
These, and very many other facts of the greatest interest to the meteorologist, were the outcome of Mr. Glaisher’s experiments. Later voyages of a similar kind have added greatly to our knowledge of the condition of the air, and it seems certain that in the future the balloon will be much more used by scientific men, and by its means they will be able to predict the weather more accurately and further ahead than at present, and learn many other things of which we are now in ignorance.
CHAPTER V
THE BALLOON IN WARFARE
But there is another practical use for the balloon to which we must now refer, and that a most important one—its employment in war-time. It was not long after the invention of this ship of the skies that soldiers began to realise what a valuable aid it might be to them in times of battle, enabling them to see inside a camp, fort, or beleaguered city, or watch the enemy’s movements from afar off. The opportunity for first putting the matter to the test very soon arose. Within a very few years of the earliest balloon experiments in France there commenced in that very country the dreadful French Revolution, and soon the nation found itself at war with all the world, and forced to hold its own, alone, against the armies of Europe. This danger quickened the minds of all to the importance of making use of every possible means of defence in their power. It was suggested that the newly discovered balloon might be turned to account, and immediately a school for military ballooning was established near Paris. Fifty young military students were trained in the new art, and suitable balloons were provided. The value of their work was soon apparent. In June 1794 was fought the battle of Fleurus, between the French and Austrians. Before the fight a balloon party had carefully observed the position of the Austrian forces, and, through the information they gave, the French were able to gain a speedy and decisive victory. In this way, and at this early stage, the value of the war balloon was at once established.
Curiously enough, Napoleon would make no use of balloons in his campaigns, and even did away with the balloon school at Paris. The reason given for his prejudice is a curious one. At the time of his coronation a large, unmanned balloon, gaily decorated, and carrying thousands of lights, was sent up from Paris during the evening’s illuminations. It was a very beautiful object, and behaved splendidly, sailing away into the night, amidst great popular rejoicing, until it was lost to sight in the darkness. But at daybreak next morning it was seen approaching the city of Rome, where it presently arrived, actually hovering over St. Peter’s and the Vatican. Then, as if its mission were fulfilled, it settled to earth, and finally fell in Lake Bracciano. But as it fell it rent itself, and left a portion of the crown with which it was ornamented on the tomb of the Roman Emperor Nero. Napoleon, who was always a superstitious man, saw in this extraordinary voyage some dreadful forecast of his own fate. He was much disturbed, and forebade the matter ever to be mentioned in his presence; nor would he henceforward have any more to do with balloons.
