by Jules Verne
Air is composed, practically speaking, of twenty-one percent oxygen and seventy-nine percent nitrogen. What happens when we breathe? It is a simple phenomenon. We absorb oxygen, which is necessary for sustaining life, from the air, and expel the nitrogen intact. Exhaled air has lost nearly five percent of its oxygen and contains an almost equal volume of carbonic acid, the end product of the combustion of the elements of the blood by the inhaled oxygen. In a closed space, therefore, after a certain time all the oxygen in the air will be replaced by carbonic acid, which is an essentially noxious gas.
The question came down to this: with the nitrogen conserved intact, how could the oxygen be replenished and how could the carbonic acid be destroyed? It was quite easy, by means of potassium chlorate and caustic potash.
Potassium chlorate is a salt which exists in the form of white flakes. When it is heated to a temperature above four hundred degrees centigrade, it is transformed into potassium chloride, and the oxygen it contains is entirely given off. Eighteen pounds of potassium chlorate yields seven pounds of oxygen: the amount the passengers needed for twenty-four hours. So much for replenishing the oxygen.
As for caustic potash, it has a strong affinity for the carbonic acid mingled in the air. It need only be agitated in order to make it combine with the carbonic acid and form potassium bicarbonate. So much for absorbing the carbonic acid.
By combining these two processes, it was possible to restore all the life-giving properties to the exhaled air. The two chemists, Reiset and Regnault, had shown this experimentally. But it must be said that so far the experiment had been performed only with animals. However great its scientific precision, its effect on men was still completely unknown.
These were the facts that Michel Ardan pointed out during the meeting at which the important question was considered. Not wishing to leave any doubt about the possibility of living on that artificial air, he offered to try it himself before the departure. But the honor of making the test was energetically demanded by J. T. Maston.
“Since I’m not going with you,” he said, “the least you can do is to let me live in the projectile for a week or so.”
The others would have been unkind to refuse him. They granted his request. He was given enough food, water, potassium chlorate, and caustic potash for eight days; then on November 12, at six o’clock in the morning, after having shaken hands with his friends and expressly instructed them not to open his prison until six o’clock on the evening of November 20, he slipped into the projectile and the opening was hermetically sealed behind him.
What happened inside the projectile during the eight days? It was impossible to tell. The thickness of its walls prevented all sounds from reaching the outside.
On November 20, at exactly six o’clock, the cover was removed from the opening. J. T. Maston’s friends were a little worried, but they were promptly reassured when they heard a loud, joyful “Hurrah!”
J. T. Maston soon appeared at the top of the cone in a triumphant pose. He had gained weight!
CHAPTER 24
THE LONGS PEAK TELESCOPE
ON OCTOBER 20 of the previous year, after the closing of the subscription, Barbicane had turned over to the Cambridge Observatory the money necessary for the construction of an enormous telescope. This telescope, whether a refracting or a reflecting one, was to be powerful enough to detect an object no more than nine feet wide on the surface of the moon.
There is an important difference between a refracting and a reflecting telescope; it will be best to recall it here. A refracting telescope is composed of a tube which has at its upper end a convex lens called the objective, and at its lower end a second lens known as the ocular, to which the observer applies his eye. Light rays from the object pass through the first lens and, by refraction, form an inverted image at its focus.* This image is observed through the ocular, which enlarges it exactly like a magnifying glass. Thus the tube of a refracting telescope is closed at both ends by the objective and the ocular.
The reflecting telescope, on the other hand, is open at its upper end. Light rays from the observed object penetrate it freely and strike a concave, i.e., converging, metal mirror. From there they are reflected to a small mirror that sends them to the ocular, which is so disposed as to magnify the image produced.
Thus in a refracting telescope it is refraction that plays the principal role, while in a reflecting telescope it is reflection. The former is sometimes called simply a refractor, the latter a reflector. The difficulty in making them lies almost entirely in making the objective, whether it be a lens or a metal mirror.
At the time when the Gun Club was preparing for its great experiment, these instruments had been highly perfected and gave magnificent results. Science had come a long way since the days when Galileo observed the heavenly bodies with his poor little seven-power refracting telescope. Since the sixteenth century, telescopes had grown considerably wider and longer, and had made it possible to probe more deeply into interstellar space. Among the refracting telescopes in operation at that time were the one at the Pulkovo Observatory in Russia, with a fifteen-inch objective;* the one made by the French optician Lerebours, also with a fifteen-inch objective; and the one at the Cambridge Observatory, with a nineteen-inch objective.
Among the reflecting telescopes there were some of remarkable power and gigantic size. The first one, made by Herschel, had a length of thirty-six feet, a mirror with a diameter of four and a half feet, and a magnification of six thousand. The second one was in Birr, Ireland, and belonged to Lord Rosse. It was forty-eight feet long, its mirror was six feet in diameter,* and its magnification was 6,400; an immense stone structure had to be built to house the instruments for maneuvering it, and to support its weight of 28,000 pounds.
Despite these colossal dimensions, however, the magnification obtained never went very far beyond six thousand. A magnification of six thousand brings the moon to an apparent distance of thirty-nine miles and makes it possible to see objects with a width of no less than sixty feet, unless they are extremely long.
In order to see the Gun Club’s projectile, which was nine feet wide and fifteen feet long, the moon would have to be brought to an apparent distance of five miles or less, and this would require a magnification of 48,000.
Such was the problem faced by the Cambridge Observatory. It would not be stopped by financial difficulties, but there were still physical difficulties to be overcome.
First of all, a choice had to be made between a refractor and a reflector. Refractors have certain advantages over reflectors. With the same objective diameter they make it possible to obtain greater magnification, because light rays passing through the lenses lose less by absorption than by reflection from the metal mirror of a reflector. But the thickness that can be given to a lens is limited: if the lens is too thick, it will not let light rays pass through it. Furthermore, the construction of such enormous lenses is difficult and the time is measured in years.
Therefore, even though the images are illuminated better in a refractor—an appreciable advantage in observing the moon, whose light is simply reflected—it was decided to use a reflector, which can be made more quickly and permits greater magnification. And since light rays lose a great deal of their intensity in passing through the earth’s atmosphere, the Gun Club decided to put the telescope on one of the highest mountains in the country, which would diminish the amount of air that would have to be traversed by the light.
As we have seen, in a reflecting telescope the ocular—that is, the magnifying glass placed before the observer’s eye—produces the magnification, and the greater the diameter and focal distance of the objective, the greater the magnification it will allow. To obtain a magnification of 48,000, the size of Herschel’s and Lord Rosse’s objectives would have to be far surpassed. There lay the difficulty, for the casting of such mirrors is a very delicate operation.
Fortunately a few years earlier a scientist at the Institut de France, Léon Foucault, had invented a way of greatly reduci
ng the time required for polishing an objective by replacing metal mirrors with silvered glass ones. One had only to cast a piece of glass to the right size, then plate it with silver. This process, which gives excellent results, was used in making the objective.
It was arranged in accordance with Herschel’s method. In his big telescope, the image of the object, reflected by the inclined mirror at one end of the tube, was formed at its other end, where the ocular was situated. Thus the observer, instead of being placed at the lower end of the tube, raised himself to its upper end, and there, with his magnifying glass, he looked into the enormous cylinder. This system had the advantage of eliminating the little mirror whose function was to reflect the image to the ocular, so the image was reflected only once instead of twice. Therefore fewer light rays were absorbed, the image was less weakened, and greater brightness was obtained.* This would be a valuable advantage in observing the projectile.
When these decisions had been made, the work was begun. According to the Cambridge Observatory’s calculations, the new telescope would have to be 280 feet long, and its mirror would have to have a diameter of sixteen feet. However colossal it might be, it would not be comparable to the 10,000-foot telescope that the astronomer Hooke proposed building several years ago. Nevertheless its construction presented great difficulties.
As for the question of location, it was quickly settled. A high mountain had to be chosen, and high mountains are not numerous in the United States.
The mountains of that great country are composed of two ranges of medium height. Between them flows the magnificent Mississippi, which the Americans would call “the king of rivers” if they were willing to accept any kind of royalty.
In the east are the Appalachians, whose tallest peak, in New Hampshire, is 6,600 feet high, which is quite modest.
In the west are the Rocky Mountains, an immense range which begins at the Straits of Magellan, runs along the west coast of South America under the name of the Andes, crosses the Isthmus of Panama, and extends across North America all the way to the Arctic.
These mountains are not very high; the Alps or the Himalayas would look down on them from their lofty heights. Their tallest peak is only 11,771 feet high, whereas Mont Blanc is 15,787 feet high, and Kinchinjunga, the highest of the Himalayas, rises 29,454 feet above sea level.
But since the members of the Gun Club wanted the telescope as well as the cannon to be within the boundaries of the United States, they had to content themselves with the Rocky Mountains. All the necessary materials and equipment were sent to Longs Peak, in Colorado Territory.
The difficulties of all kinds that the American engineers had to overcome, and the wonders of daring and skill that they accomplished, could not be described by tongue or pen. It was a truly spectacular feat. Huge stones, heavy forged parts, enormous pieces of the cylinder, and the objective, with a weight of 30,000 pounds, had to be brought up above the snow line, over 10,000 feet high, after having been brought across deserted prairies and through dense forests and fearful rapids, far from all centers of population, in wild regions where each detail of life became an almost insoluble problem. But the Americans’ genius triumphed over these countless obstacles. In late September, less than a year after work had begun, the gigantic tube of the telescope, 284 feet long, was pointing into the air. It was suspended from an enormous iron framework; an ingenious mechanism enabled the observer to aim it at any point in the sky and follow the heavenly bodies from one horizon to the other as they moved through space.
It has cost more than $400,000. The first time it was aimed at the moon, the observers were both curious and apprehensive. What were they going to discover in the field of that 48,000-power telescope? Populations, herds of lunar animals, cities, lakes, oceans? No, they saw nothing that science had not known already. They were, however, able to determine the moon’s volcanic nature with absolute precision.
Before serving the Gun Club, the Longs Peak telescope rendered immense services to astronomy. With its great power, it was able to scan the outermost reaches of the heavens; the apparent diameters of stars were rigorously measured, and Mr. Clarke of the Cambridge Observatory decomposed the crab nebula in Taurus, which Lord Rosse’s telescope had never been able to resolve.
* The point at which the light rays are reunited after having been refracted.
* It cost 80,000 rubles ($60,000).
* One often hears of refracting telescopes of much greater length. One of them, with a length of 300 feet, was installed, under Domini Cassini’s direction, at the Paris Observatory. But it should be pointed out that these telescopes had no tube. The objective was suspended in the air by means of masts, and the observer, holding his ocular in his hand, placed himself as close to the focus of the objective as possible. It is easy to understand how difficult these instruments were to use, and particularly how difficult it was to center two lenses under such conditions.
* These reflectors are called “front view telescopes.”
CHAPTER 25
FINAL DETAILS
IT WAS November 22. The supreme departure was to take place ten days later. Only one operation remained to be carried out, a dangerous, delicate operation that required infinite precautions, and against whose success Captain Nicholl had made his third bet: the operation of loading the cannon, of putting the 400,000 pounds of guncotton into it. Nicholl had thought, not without reason, perhaps, that the handling of such a formidable quantity of guncotton would bring on a grave catastrophe, or at any rate that the eminently explosive mass would ignite itself under the pressure of the projectile.
The serious dangers involved were increased still more by the carelessness and unconcern of the Americans, who, during the Civil War, did not hesitate to load their bombshells with cigars in their mouths. But Barbicane was determined that his experiment would not fail before it even got under way; he chose his best workers, kept his eye on them at all times and, by caution and precautions, was able to put the chances of success in his favor.
First of all, he was careful not to bring the whole charge into the enclosure at once. He had it brought in little by little in tightly sealed caissons. The 400,000 pounds of guncotton was divided into 500-pound portions and placed in 800 cartridge bags made by the best craftsmen in Pensacola. The caissons held ten bags each. They came in one by one on the railroad from Tampa. In that way there was never any more than 5,000 pounds of guncotton within the enclosure at any given time. As soon as each caisson arrived it was unloaded by barefoot workers. The cartridge bags were taken to the cannon and lowered into it by means of hand cranes. All steam machinery had been removed from the vicinity, and all fires had been put out for two miles around. Merely protecting that mass of guncotton from the heat of the sun, even in November, was a major concern. The work was done preferably at night, with the aid of a Ruhmkorff apparatus which cast bright light all the way to the bottom of the cannon. There the cartridge bags were stacked with perfect regularity and connected with the wires that were to bring an electric spark to the center of each one of them simultaneously, for it was by means of a battery that the guncotton was going to be ignited.
The wires, surrounded by an insulating material, were united into a single cable that passed through an opening in the wall of the cannon just below the height at which the projectile was to be placed, then went up to the surface of the ground through a hole in the stonework that had been made for that purpose. When it reached the top of Stone Hill, the cable continued for a distance of two miles, supported by poles, until it reached a powerful Bunsen battery, after passing through a switch. One would have only to push the button of the switch to make the current flow and ignite the 400,000 pounds of guncotton. Needless to say, the battery was not to be activated until the last moment.
By November 28 the 800 cartridge bags were stacked at the bottom of the cannon. This part of the operation had been successful. But what worries, apprehensions, and struggles Barbicane had been through! He had vainly tried to keep all v
isitors away from Stone Hill: every day people had climbed over the stockade, and some of them had carried lack of caution to the point of madness by smoking in the midst of the bags of guncotton. Barbicane had flown into a rage several times a day. J. T. Maston had helped as best he could, driving away intruders with great vigor and picking up the burning cigar butts they had tossed here and there. It was a hard job, because there were more than 300,000 people thronged around the enclosure. Michel Ardan had volunteered to escort the caissons to the mouth of the cannon, but when Barbicane saw him holding a big cigar between his lips as he chased away careless bystanders and gave them a bad example at the same time, he realized that he could not count on that daring smoker, and he had to have him watched more closely than anyone else.
Finally, since there is a God for artillerymen, nothing blew up and the loading operation was completed. Captain Nicholl was in serious danger of losing the third part of his bet, although the projectile still had to be placed in the cannon and lowered onto the deep pile of guncotton.
But before beginning that operation, the objects necessary for the journey were methodically stowed in the projectile. There were quite a few of them, and if Michel Ardan had been allowed to have his way they would soon have taken up all the space reserved for the passengers. The charming Frenchman had an incredible number of things that he wanted to take to the moon, and they were as useless as they were numerous. But Barbicane intervened and the list of objects was reduced to what was strictly necessary.
Several thermometers, barometers, and telescopes were placed in the instrument chest.
The passengers were curious to examine the moon during the journey; to facilitate their scrutiny of that new world they decided to take Beer and Moedler’s excellent map, the Mappa Selenographica, printed in four sheets and rightly regarded as a masterpiece of observation and patience. It reproduced with scrupulous accuracy the slightest details of that portion of the moon which is turned toward the earth; mountains, valleys, basins, craters, peaks, and rills were shown with their exact dimensions, correct locations and names, from Mount Doerfel and Mount Leibnitz, whose tall peak stands in the eastern part of the visible disk, to the Mare Frigoris, which lies in the northern circumpolar region. It was a valuable document for the three explorers, because they could already study the new land before they had ever set foot on it.
