CHAPTER IV

THE 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 scientific ascents 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 sixty years 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 to an 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 the Vauxhall 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.

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, twinkling like 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 only a 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 1 P.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 of two 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