It is to Mr. Glaisher and Mr. c.o.xwell, however, that the highest honours of scientific aerostation belong. The ascents made by these gentlemen--Mr. Glaisher being the scientific observer, and Mr. c.o.xwell the practical aeronaut--have become matters of history. Not only did they, in the course of a large number of ascents undertaken under the auspices of the British a.s.sociation, succeed in gathering much valuable meteorological information, but they reached a greater height than that ever gained on any previous or subsequent occasion, and penetrated into that distant region of the skies in which it has been satisfactorily proved that no life can be long maintained. It was on the 5th of September, 1862, that Mr. Glaisher and Mr. c.o.xwell made the famous ascent in which they reached the greatest height ever attained by an aeronaut, and were so nearly sacrificed to their unselfish daring. Mr.

Glaisher has given an admirable account of this ascent, which took place from Wolverhampton. He says:--"Our ascent had been delayed, owing to the unfavourable state of the weather. It commenced at three minutes past one p.m., the temperature of the air being 59 degrees, and the dew-point 48 degrees. At the height of one mile the temperature was 41 degrees and the dew-point 38 degrees. Shortly after wards clouds were entered of about 1,100 feet in thickness. Upon emerging from them at seventeen minutes past one, I tried to take a view of their surface with the camera, but the balloon was ascending too rapidly and spiraling too quickly to allow me to do so. The height of two miles was reached at twenty-one minutes past one. The temperature of the air had fallen to 32 degrees and the dew-point to 26 degrees. The third mile was pa.s.sed at twenty-eight minutes past one, with an air temperature of 18 degrees, and a dew-point of 13 degrees. The fourth mile was pa.s.sed at thirty-nine minutes past one, with an air temperature of 8 degrees, and a dew-point of minus 6 degrees and the fifth mile about ten minutes later, with an air temperature minus 5 degrees, and a dew-point minus 36 degrees.

"Up to this time I had experienced no particular inconvenience. When at the height of 26,000 feet I could not see the fine column of the mercury in the tube; then the fine divisions on the scale of the instrument became invisible. At that time I asked Mr. c.o.xwell to help me to read the instruments, as I experienced a difficulty in seeing them. In consequence of the rotary motion of the balloon, which had continued without ceasing since the earth was left, the valve line had become twisted, and he had to leave the car, and to mount into the ring above to adjust it. At that time I had no suspicion of other than temporary inconvenience in seeing. Shortly afterwards I laid my arm upon the table, possessed of its full vigour; but directly after, being desirous of using it, I found it powerless. It must have lost its power momentarily. I then tried to move the other arm, but found it powerless also. I next tried to shake myself, and succeeded in shaking my body. I seemed to have no legs. I could only shake my body. I then looked at the barometer, and whilst I was doing so my head fell on my left shoulder. I struggled, and shook my body again, but could not move my arms. I got my head upright, but for an instant only, when it fell on my right shoulder; and then I fell backwards, my back resting against the side of the car, and my head on its edge. In that position my eyes were directed towards Mr. c.o.xwell in the ring. When I shook my body I seemed to have full power over the muscles of the back, and considerable power over those of the neck, but none over my limbs. As in the case of the arms, all muscular power was lost in an instant from my back and neck. I dimly saw Mr. c.o.xwell in the ring, and endeavoured to speak, but could not do so; when in an instant intense black darkness came over me, and the optic nerve lost power suddenly. I was still conscious, with as active a brain as whilst writing this. I thought I had been seized with asphyxia, and that I should experience no more, as death would come unless we speedily descended. Other thoughts were actively entering my mind when I suddenly became unconscious, as though going to sleep. I could not tell anything about the sense of hearing: the perfect stillness of the regions six miles from the earth--and at that time we were between six and seven miles high--is such that no sound reaches the ear. My last observation was made at 29,000 feet, about fifty-four minutes past one. I suppose two or three minutes elapsed between my eyes becoming insensible to seeing the fine divisions and fifty-four minutes past one, and that other two or three minutes elapsed before I became unconscious; therefore I think that took place about fifty-six or fifty-seven minutes past one. Whilst powerless I heard the words 'temperature,' and 'observation,' and I knew Mr. c.o.xwell was in the car, speaking to me, and endeavouring to rouse me; and therefore consciousness and hearing had returned. I then heard him speak more emphatically, but I could not speak or move. Then I heard him say, 'Do try; now do!' Then I saw the instruments dimly, next Mr. c.o.xwell, and very shortly I saw clearly. I rose in my seat and looked round, as though waking from sleep, and said to Mr. c.o.xwell, 'I have been insensible.' He said, 'Yes; and I too, very nearly.' I then drew up my legs, which had been extended out before me, and took a pencil in my hand to note my observations. Mr. c.o.xwell informed me that he had lost the use of his hands, which were black, and I poured brandy over them. I resumed my observations at seven minutes past two. I suppose three or four minutes were occupied from the time of my hearing the words 'temperature' and 'observation,' until I began to observe. If so, then returning consciousness came at four minutes past two, and that gives about seven minutes of total insensibility. Mr.

c.o.xwell told me that in coming from the ring he thought for a moment that I had laid back to rest myself; that he spoke to me without eliciting a reply; that he then noticed that my legs projected, and my arms hung down by my side. That my countenance was serene and placid, without earnestness or anxiety, he had noticed before going into the ring. It then struck him that I was insensible. He wished then to approach me, but could not, and he felt insensibility coming over himself. He became anxious to open the valve, but, in consequence of having lost the use of his hands, he could not; and ultimately he did so by seizing the cord with his teeth and dipping his head two or three times. No inconvenience followed our insensibility. When we dropped it was in a country where no accommodation of any kind could be obtained, so that we had to walk between seven and eight miles. At the time of ceasing our observations the ascent was at the rate of 1,000 feet per minute, and on resuming observations the descent was at the rate of 2,000 feet per minute. These two positions must be connected, having relation to the interval of time which elapsed between them; and they can scarcely be connected at a point less than 36,000 or 37,000 feet high. Again, a very delicate minimum thermometer was found to read minus 12 degrees, and that reading would indicate an elevation exceeding 36,000 feet. There cannot be any doubt that the balloon attained the great height of seven miles--the greatest ever reached. In this ascent six pigeons were taken up. One was thrown out at three miles. It extended its wings, and dropped like a piece of paper. A second at four miles, and it flew with vigour. A third between four and five miles, and it fell downwards. A fourth was thrown out at four miles in descending, and it alighted on the top of the balloon. Two were brought to the ground. One was dead, and the other was ill, but recovered so as to fly away in a quarter of an hour."

The results gathered by Mr. Glaisher from his numerous ascents are very interesting. He found that in no instance did the temperature of the air decrease uniformly with the increase of height. In fact, the decrease in the first mile is double that in the second, and nearly four times as great as the change of temperature in the fifth mile. The distribution of aqueous vapour in the air is no less remarkable. The temperature of the dew-point on leaving the earth decreases less rapidly than the temperature of the air; so that the difference between the two temperatures becomes less and less, till the vapour or cloud plane is reached, when they are usually together, and always most nearly approach each other, and that point is usually at about the height of one mile.

On leaving the upper surface of cloud, the dew point decreases more rapidly than the air, and at extremely high situations the difference between the two temperatures is wonderfully great, indicating an extraordinary degree of dryness, and an almost entire absence of water.

Under these circ.u.mstances, the presence of cirrus clouds far above this dry region, apparently as much above as when viewed from the earth, is very remarkable, and leads to the conclusion that they are not composed of water.

In the propagation of sound, M. Glaisher made many curious experiments.

In one ascent (July 17th) he found, when at a distance of 11,800 feet above the earth, that a band was heard; at a height of 22,000 feet, a clap of thunder was heard; and at a height of 10,070 feet, the report of a gun was heard. On one occasion, he heard the dull hum of London at a height of 9,000 feet above the city, and on another occasion, the shouting of many thousands of persons could not be heard at the height of 4,000 feet.

Chapter IV. Balloons Made Useful in Warfare.

Wars of the French Republic--Company of "Ballooneers"-- Battle of Fleurus--The Balloons of Egypt--Napoleon--Modern Services War in Italy--War in America--Conclusion.

We will conclude our work with a glance at aerostation as applied to warfare. Scarcely had the first ascents astonished the world, than the more adventurous spirits began to use the new discovery for a thousand purposes directly useful to man. The first point of view in which aerostation was regarded, was in that of its practical utility If one refers to the pre-occupations of the time--to the great events then occurring in the history of France, one will easily understand that the Committee of Public Safety soon thought of employing balloons in the observation of the forces and the movements of hostile troops. In 1794, the idea was practically carried out, and the French armies were provided with two companies of aeronauts. The command of one of these companies was given to Captain Coutelle, a young physicist of great talent, who rendered memorable services at the battle of Fleurus. The balloons were not thrown free, but were retained attached by means of long cords. In this way they took up, so to speak, aerial posts of observation. Placed in his car, the captain transmitted his instructions to his men below by means of coloured flags. Coutelle has left us a lively narrative of certain incidents connected with one of the grand days of the old Republic. He had been commissioned by the Committee of Public Safety to go to Maubeuge, where Jourdan's army was encamped, and to offer him the use of his balloon. The representative to whom the young doctor presented his commission, knew nothing about balloons, and not being able to understand the order of the Committee of Public Safety, it suddenly dawned upon him that Coutelle, with his trumpery forgery about balloons, was nothing else than a spy, and he was about to have him shot. The genuineness of the order from the Committee, however, was proved, and Coutelle's case was listened to.

"The army was at Beaumont," says Coutelle, "and the enemy, placed at a distance of only three miles, could attack at any moment. The general told me this fact, and engaged me to return and communicate it to the Committee. This I did. The Commission then felt the necessity of making an experiment with a balloon that could raise two persons, and the minister placed at my service the garden and the little mansion of Meudon. Many of the members of the Commission came to witness the first ascent of a balloon held in hand, like a kite, by means of two cords.

The Commissioners ordered me to place myself in the car, and instructed me as to a number of signals which I must repeat, and observations which I must make. I raised myself to the full length of the cord, a height of 1,500 feet, and at this height, with the help of a gla.s.s, I could distinctly see the seven bends of the river Seine. On returning to the earth, I received the compliments of the Commission.

"Arrived at Maubeuge, my first care was to find a suitable spot to erect my furnace, and to make every preparation for the arrival of my balloon from Meudon. Each day my observations contained something new either in the works which the Austrians had thrown up during the night, or in the arrangement of their forces. On the fifth day a piece of cannon had been brought to bear upon the balloon, and shots were fired at me as soon as I appeared above the ramparts. None of the shots took effect, and on the following day the piece was no longer in position. Experience enforced upon me the necessity of forming some provision against these unexpected attacks. I employed the night in fixing cords all round the middle of my balloon. Each of the aerostiers had charge of one of the ropes, and by means of them I could easily move about, and thus get myself out of range of any gun that had been trained to bear against me. I was afterwards ordered to make a reconnaissance at Mayence, and I posted myself between our lines and the enemy at half range of cannon. When the wind, which was tempestuous at first, became calmer, I was able to count the number of cannon on the ramparts, as well as the troops that marched through the streets and in the squares.

"Generally the soldiers of the enemy, all who saw the observer watching them and taking notes, came to the idea that they could do nothing without being seen. Our soldiers were of the same opinion, and consequently they regarded us with great admiration and trust. On the heavy marches they brought us prepared food and wine, which my men were hardly able to get for themselves, so closely did they require to attend to the ropes. We were encamped upon the banks of the Rhine at Manheim when our general sent me to the opposite bank to parley. As soon as the Austrian officers were made aware that I commanded the balloon, I was overwhelmed with questions and compliments.

"What causes an impression which, till one is accustomed to it, is very alarming, is the noise which the balloon makes when it is struck by successive gales of wind. When the wind has pa.s.sed, the balloon, which has been pressed into a concave form by the wind, suddenly resumes its globular form with a loud noise heard at a great distance. The silk of the balloon would often burst in a case of this kind, were it not for the restraining power of the network."

After the days of Coutelle we do not read that balloons were made much use of in warfare. The only ascent in the Egypt campaign was that of a tricolor balloon thrown up to commemorate a fete. That Napoleon knew full well the value of the scientific discoveries of his time is clear from the following conversation with a learned Mohammedan, which took place in the great pyramid of Cheops:--

Mussamed. "n.o.ble successor of Alexander, honour to shine invincible arms, and to the unexpected lightning with which your warriors are furnished."

Bonaparte. "Do you believe that that lightning is the work of the children of men? Allah has placed it in our hands by means of the genius of war."

Mussamed. "We recognised by your arms that it is Allah that has sent you--the Delta and all the neighbouring countries are full of thy miracles. But would you be a conqueror if Allah did not permit you?"

Bonaparte. "A celestial body will point by my orders to the dwelling of the clouds, and lightning will descend towards the earth, along a rod of metal from which I can call it forth."

Napoleon did not favour the use of balloons in war. Perhaps it was because he himself had such a splendid genius for war that he depended alone upon himself, and scorned a.s.sistance. Perhaps it was because if balloons were discovered to be of real utility, his enemies might make use of them as well as himself, and France retain no special advantage in them. But however this may be, on his return from Egypt he sold the balloon of Fleurus to Robertson. The company of ballooneers was dissolved, and the balloons themselves disappeared in smoke.

During the war in America, the role which the balloon played was a more important one. The Government of the United States conferred the t.i.tle of aeronautic engineer upon Mr. Allan, of Rhode Island, who originated the idea of communicating by a telegraphic wire from the balloon to the camp. The first telegraphic message which was transmitted from the aerial regions is that of Professor Love, at Washington, to the President of the United States. The following is this despatch:--

"WASHINGTON, Balloon the 'Enterprise.'

"SIR,--The point of observation commands an extent of nearly fifty miles in diameter. The city, with its girdle of encampments, presents a superb scene. I have great pleasure in sending you this despatch--the first that has been telegraphed from an aerial station--and to know that I should be so much encouraged, from having given the first proof that the aeronautic science can render great a.s.sistance in these countries."

In the month of September, 1861, one of the most hardy aeronauts (La Mountain) furnished important information to General M'Clellan. The balloon of La Mountain, which arose from the northern camp upon the Potomac, pa.s.sed above Washington. La Mountain then cut the cord that connected his balloon with the earth, and rising rapidly to the height of a mile and a half, he found himself directly above his enemies'

lines. There he was able to observe perfectly their position and their movements. He then threw over ballast, and ascended to the height of three miles. At this height he encountered a current which carried him in the direction of Maryland, where he descended in safety. General M'Clellan was so much satisfied with the observations taken in the balloon, that, at his request, the order was given to the War Department to construct four new balloons.

If this volume of "The Library of Wonders" had not had for its single object "balloons and their history," we would have devoted a chapter to the numerous attempts made to steer balloons. We shall only say here that aerial navigation should be divided into two kinds with balloons, and without balloons. In the first case, it is limited to the study of aerial currents, and to the art of rising to those currents which suit the direction of the voyage undertaken. The balloon is not the master of the atmosphere; on the contrary, it is its powerless slave. In the second case, the discovery of Montgolfier is useless; and the question is, to find out a new machine capable of flying in the air, and at the same time heavier than the air. Birds are, without doubt, the best models to study. But with what force shall we replace LIFE? The air-boat of M. Pline seems to us one of the best ideas; but the working of it presents many difficulties. Let us find a motive power at once light and powerful (aluminium and electricity, for example), and we will have definitively conquered the empire of the air.