CHAPTER IVTHE BALLOON AS A SCIENTIFIC INSTRUMENT
So far, in our history of aeronautics, we have referred to ballooning only as a sport or pastime for the amusement of spectators, and for the gratifying of a love of adventure. It is now time to speak of the practical uses of the balloon, and how it has been employed as a most valuable scientific instrument to teach us facts about the upper atmosphere, its nature and extent, the clouds, the winds and their ways, the travel of sounds, and many other things of which we should otherwise be ignorant.
Before the invention of the balloon men were quite unaware of the nature of the air even a short distance above their heads. In those days high mountain climbing had not come into fashion, and when Pilâtre de Rozier made the first ascent, it was considered very doubtful whether he might be able to exist in the strange atmosphere aloft. Charles and Roberts were the first to make scientific observations from a balloon, for they took up a thermometer and barometer, and made certain rough records, as also did other early aeronauts. The most interesting purely scientificascents of early days, however, were made in the autumn of 1804, from Paris, by Gay Lussac, a famous French philosopher. He took up with him all manner of instruments, among them a compass (to see if the needle behaved the same as on earth), an apparatus to test the electricity of the air, thermometers, barometers, and hygrometers, carefully exhausted flasks in which to bring down samples of the upper air, birds, and even insects and frogs, to see how great heights affected them. In his second voyage his balloon attained the enormous altitude of 23,000 feet, or more than four miles and a quarter, and nearly 2000 feet higher than the highest peaks of the Andes. At this tremendous height the temperature fell to far below freezing-point, and the aeronaut became extremely cold, though warmly clad; he also felt headache, a difficulty in breathing, and his throat became so parched that he could hardly swallow. Nevertheless, undismayed by the awfulness of his position, he continued making his observations, and eventually reached the ground in safety, and none the worse for his experience.
Gay Lussac’s experiments at least proved that though the air becomes less and less dense as we ascend into it, it remains of the same nature and constitution. His second voyage also showed that the limit to which man could ascend aloft into the sky and yet live had not yet been reached. Almost sixtyyears later other scientific ascents threw fresh light on this point, and also continued the other investigations that Gay Lussac had commenced.
Towards the close of Charles Green’s famous career, scientific men in England woke up to the fact that the use of a balloon as an important means for obtaining observations on meteorology and other matters had of late been very much neglected. The British Association took the matter up, and provided the money for four scientific ascents, which were made by Mr. Welsh of Kew Observatory, a trained observer. Green was the aeronaut chosen to accompany him, and the balloon used was none other than the great Nassau balloon, of whose many and wonderful adventures we have already spoken. Green was then nearly seventy years of age, but his skill as an aeronaut was as great as ever, and Welsh was able to obtain many valuable records. During the last voyage a height was attained almost as great as that reached by Gay Lussac, and both men found much difficulty in breathing. While at this elevation they suddenly noticed they were rapidly approaching the sea, and so were forced to make a very hasty descent, in which many of the instruments were broken.
The veteran Green lived to a ripe old age, dying in 1870, aged eighty-five. When a very old man he still delighted in taking visitors toan outhouse where he kept the old Nassau balloon, now worn out and useless, and, handling it affectionately, would talk of its famous adventures and his own thousand ascents, during which he had never once met with serious accident or failure. After his death the old balloon passed into the hands of another equally famous man, who, after Green’s retirement, took his place as the most celebrated English aeronaut of the day.
This was Henry Coxwell. He was the son of a naval officer, and was brought up to the profession of a dentist. But when a boy of only nine years old he watched, through his father’s telescope, a balloon ascent by Green, which so fired his imagination that henceforward balloons filled all his thoughts. As he grew older the fascination increased upon him. He would go long distances to see ascents or catch glimpses of balloons in the air, and he was fortunate enough to be present at the first launching of the great Nassau balloon. He did not get the chance of a voyage aloft, however, till he was twenty-five; but after this nothing could restrain his ardour, and, throwing his profession to the winds, he made ascent after ascent on all possible occasions.
In one of his early voyages he met with what he describes as one of the most perilous descents in the whole history of ballooning. The occasion was an evening ascent made from theVauxhall Gardens one autumn night of 1848. The aeronaut was a Mr. Gypson, and besides Mr. Coxwell there were two other passengers, one of whom was the well-known mountaineer and lecturer, Albert Smith. A number of fireworks which were to be displayed when aloft were slung on a framework forty feet below the car.
Coxwell.Glaisher.
Coxwell.
Glaisher.
The balloon rose high above London, and the party were amazed and delighted with the strange and lovely view of the great city by night, all sight of the houses being lost in the darkness, and the thousands of gas lamps, outlining the invisible streets and bridges, twinklinglike stars in a blue-black sky. Coxwell was sitting, not in the car, but in the ring of the balloon, and presently, when they were about 7000 feet above the town, he noticed that the silk, the mouth of which appears to have been fastened, was growing dangerously distended with the expanding gas. By his advice the valve was immediately pulled, but it was already too late; the balloon burst, the gas escaped with a noise like the escape of steam from an engine, the silk collapsed, and the balloon began to descend with appalling speed, the immense mass of loose silk surging and rustling frightfully overhead. Everything was immediately thrown out of the car to break the fall; but the wind still seemed to be rushing past at a fearful rate, and, to add to the horror of the aeronauts, they now came down through the remains of the discharged fireworks floating in the air. Little bits of burning cases and still smouldering touch-paper blew about them, and were caught in the rigging. These kindled into sparks, and there seemed every chance of the whole balloon catching alight. They were still a whole mile from the ground, and this distance they appear to have covered in less than two minutes. The house-tops seemed advancing up towards them with awful speed as they neared earth. In the end they were tossed out of the car along the ground, and it appeared a perfect marvel to them all that they escaped with onlya severe shaking. This adventure did not in the least abate Coxwell’s ardour for ballooning, and exactly a week later he and Gypson successfully made the same ascent from the same place, and in the same balloon—and loaded with twice the number of fireworks!
But Coxwell’s most celebrated voyage of all took place some years later, on the occasion of a scientific voyage made in company with Mr. James Glaisher. In 1862 the British Association determined to continue the balloon observations which Mr. Welsh had so successfully commenced, but this time on a larger scale. The observer was to be Mr. Glaisher of Greenwich Observatory, and Mr. Coxwell, who by this time had become a recognised aeronaut, undertook the management of the balloon. The first ascents were made in July and August. Mr. Glaisher took up a most elaborate and costly outfit of instruments, which, however, were badly damaged at the outset during a very rapid descent, made perforce to avoid falling in the “Wash.” On each occasion a height of over four miles was attained; but on the third voyage, which was in September, it was decided to try and reach yet greater altitudes.
The balloon with its two passengers left Wolverhampton at 1P.M.—the temperature on the ground being 59°. At about a mile high a dense cloud was entered, and the thermometer fell to 36°. In nineteen minutes a height oftwo miles was reached, and the air was at freezing-point. Six minutes later they were three miles aloft, with the thermometer still falling; and by the time four miles high was attained the mercury registered only 8°.
In forty-seven minutes from the start five miles had been passed; and now the temperature was 2° below zero. Mr. Coxwell, who was up in the ring of the balloon and exerting himself over the management of it, found he was beginning to breathe with great difficulty. Mr. Glaisher, sitting quietly in the car watching his instruments, felt no inconvenience. More ballast was thrown out, and the balloon continued to rise apace; and soon Mr. Glaisher found his eyes growing strangely dim. He could not see to read his thermometer, or distinguish the hands of his watch. He noticed the mercury of the barometer, however, and saw that a height of 29,000 feet had been reached, and the balloon was still rising. What followed next had best be told in Mr. Glaisher’s ownwords:—
“Shortly after I laid my arm upon the table, possessed of its full vigour, but on being desirous of using it, I found it useless. Trying to move the other arm, I found it powerless also. Then I tried to shake myself and succeeded, but I seemed to have no limbs. In looking at the barometer my head fell over my left shoulder. I struggled and shook my body again, but could not move my arms.Getting my head upright for an instant only, it fell on my right shoulder; then I fell backwards, my body resting against the side of the car, and my head on the edge. I dimly saw Mr. Coxwell and endeavoured to speak, but could not. In an instant intense darkness overcame me; but I was still conscious, with as active a brain as at the present moment while writing this. I thought I had been seized with asphyxia, and believed I should experience nothing more, as death would come unless we speedily descended. Other thoughts were entering my mind, when I suddenly became unconscious as on going to sleep.” Mr. Glaisher adds: “I cannot tell anything of the sense of hearing, as no sound reaches the ear to break the perfect stillness and silence of the regions between six and seven miles above the earth.”
Meanwhile, as stated, Mr. Coxwell was up in the ring, trying to secure the valve-line, which had become twisted. To do this he had taken off a pair of thick gloves he had been wearing, and in the tremendous cold of that awful region the moment his bare hands rested on the metal of the ring they became frost-bitten and useless. Looking down, he saw Mr. Glaisher in a fainting condition, and called out to him, but received no answer. Thoroughly alarmed by this time, he tried to come down to his companion’s assistance; but nowhishands also had become lifeless, andhe felt unconsciousness rapidly stealing over him.
Quickly realising that death to both of them would speedily follow if the balloon continued to ascend, Mr. Coxwell now endeavoured to pull the valve-line; but he found it impossible to do so with his disabled hands. Fortunately he was a man of great bodily strength, as well as of iron nerve, and by a great effort he succeeded in catching the valve-linein his teeth. Then, putting his whole weight upon it, he managed to pull open the valve, and hold it until the balloon took a decided turn downwards. This saved them. As lower regions were reached, where the air was denser, Mr. Glaisher began to recover, and by the time they came to the ground neither of these two brave men were any the worse for their extraordinary experience.
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 fullyseven 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 windsaffect 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.