From the Earth to the Moon; and, Round the Moon by Jules Verne (books to read this summer .TXT) 📕
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- Author: Jules Verne
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So, then the moon displays invariably the same face to the earth; nevertheless, to be quite exact, it is necessary to add that, in consequence of certain fluctuations of north and south, and of west and east, termed her libration, she permits rather more than half, that is to say, five-sevenths, to be seen.
As soon as the ignoramuses came to understand as much as the director of the observatory himself knew, they began to worry themselves regarding her revolution round the earth, whereupon twenty scientific reviews immediately came to the rescue. They pointed out to them that the firmament, with its infinitude of stars, may be considered as one vast dial-plate, upon which the moon travels, indicating the true time to all the inhabitants of the earth; that it is during this movement that the Queen of Night exhibits her different phases; that the moon is full when she is in opposition with the sun, that is when the three bodies are on the same straight line, the earth occupying the center; that she is new when she is in conjunction with the sun, that is, when she is between it and the earth; and, lastly that she is in her first or last quarter, when she makes with the sun and the earth an angle of which she herself occupies the apex.
Regarding the altitude which the moon attains above the horizon, the letter of the Cambridge Observatory had said all that was to be said in this respect. Every one knew that this altitude varies according to the latitude of the observer. But the only zones of the globe in which the moon passes the zenith, that is, the point directly over the head of the spectator, are of necessity comprised between the twenty-eighth parallels and the equator. Hence the importance of the advice to try the experiment upon some point of that part of the globe, in order that the projectile might be discharged perpendicularly, and so the soonest escape the action of gravitation. This was an essential condition to the success of the enterprise, and continued actively to engage the public attention.
Regarding the path described by the moon in her revolution round the earth, the Cambridge Observatory had demonstrated that this path is a re-entering curve, not a perfect circle, but an ellipse, of which the earth occupies one of the foci. It was also well understood that it is farthest removed from the earth during its apogee, and approaches most nearly to it at its perigee.
Such was then the extent of knowledge possessed by every American on the subject, and of which no one could decently profess ignorance. Still, while these principles were being rapidly disseminated many errors and illusory fears proved less easy to eradicate.
For instance, some worthy persons maintained that the moon was an ancient comet which, in describing its elongated orbit round the sun, happened to pass near the earth, and became confined within her circle of attraction. These drawing-room astronomers professed to explain the charred aspect of the moon—a disaster which they attributed to the intensity of the solar heat; only, on being reminded that comets have an atmosphere, and that the moon has little or none, they were fairly at a loss for a reply.
Others again, belonging to the doubting class, expressed certain fears as to the position of the moon. They had heard it said that, according to observations made in the time of the Caliphs, her revolution had become accelerated in a certain degree. Hence they concluded, logically enough, that an acceleration of motion ought to be accompanied by a corresponding diminution in the distance separating the two bodies; and that, supposing the double effect to be continued to infinity, the moon would end by one day falling into the earth. However, they became reassured as to the fate of future generations on being apprised that, according to the calculations of Laplace, this acceleration of motion is confined within very restricted limits, and that a proportional diminution of speed will be certain to succeed it. So, then, the stability of the solar system would not be deranged in ages to come.
There remains but the third class, the superstitious. These worthies were not content merely to rest in ignorance; they must know all about things which had no existence whatever, and as to the moon, they had long known all about her. One set regarded her disc as a polished mirror, by means of which people could see each other from different points of the earth and interchange their thoughts. Another set pretended that out of one thousand new moons that had been observed, nine hundred and fifty had been attended with remarkable disturbances, such as cataclysms, revolutions, earthquakes, the deluge, etc. Then they believed in some mysterious influence exercised by her over human destinies—that every Selenite was attached to some inhabitant of the earth by a tie of sympathy; they maintained that the entire vital system is subject to her control, etc. But in time the majority renounced these vulgar errors, and espoused the true side of the question. As for the Yankees, they had no other ambition than to take possession of this new continent of the sky, and to plant upon the summit of its highest elevation the star- spangled banner of the United States of America.
THE HYMN OF THE CANNON-BALL
The Observatory of Cambridge in its memorable letter had treated the question from a purely astronomical point of view. The mechanical part still remained.
President Barbicane had, without loss of time, nominated a working committee of the Gun Club. The duty of this committee was to resolve the three grand questions of the cannon, the projectile, and the powder. It was composed of four members of great technical knowledge, Barbicane (with a casting vote in case of equality), General Morgan, Major Elphinstone, and J. T. Maston, to whom were confided the functions of secretary. On the 8th of October the committee met at the house of President Barbicane, 3 Republican Street. The meeting was opened by the president himself.
“Gentlemen,” said he, “we have to resolve one of the most important problems in the whole of the noble science of gunnery. It might appear, perhaps, the most logical course to devote our first meeting to the discussion of the engine to be employed. Nevertheless, after mature consideration, it has appeared to me that the question of the projectile must take precedence of that of the cannon, and that the dimensions of the latter must necessarily depend on those of the former.”
“Suffer me to say a word,” here broke in J. T. Maston. Permission having been granted, “Gentlemen,” said he with an inspired accent, “our president is right in placing the question of the projectile above all others. The ball we are about to discharge at the moon is our ambassador to her, and I wish to consider it from a moral point of view. The cannon-ball, gentlemen, to my mind, is the most magnificent manifestation of human power. If Providence has created the stars and the planets, man has called the cannon-ball into existence. Let Providence claim the swiftness of electricity and of light, of the stars, the comets, and the planets, of wind and sound—we claim to have invented the swiftness of the cannon-ball, a hundred times superior to that of the swiftest horses or railway train. How glorious will be the moment when, infinitely exceeding all hitherto attained velocities, we shall launch our new projectile with the rapidity of seven miles a second! Shall it not, gentlemen—shall it not be received up there with the honors due to a terrestrial ambassador?”
Overcome with emotion the orator sat down and applied himself to a huge plate of sandwiches before him.
“And now,” said Barbicane, “let us quit the domain of poetry and come direct to the question.”
“By all means,” replied the members, each with his mouth full of sandwich.
“The problem before us,” continued the president, “is how to communicate to a projectile a velocity of 12,000 yards per second. Let us at present examine the velocities hitherto attained. General Morgan will be able to enlighten us on this point.”
“And the more easily,” replied the general, “that during the war I was a member of the committee of experiments. I may say, then, that the 100-pounder Dahlgrens, which carried a distance of 5,000 yards, impressed upon their projectile an initial velocity of 500 yards a second. The Rodman Columbiad threw a shot weighing half a ton a distance of six miles, with a velocity of 800 yards per second—a result which Armstrong and Palisser have never obtained in England.”
“This,” replied Barbicane, “is, I believe, the maximum velocity ever attained?”
“It is so,” replied the general.
“Ah!” groaned J. T. Maston, “if my mortar had not burst—”
“Yes,” quietly replied Barbicane, “but it did burst. We must take, then, for our starting point, this velocity of 800 yards. We must increase it twenty-fold. Now, reserving for another discussion the means of producing this velocity, I will call your attention to the dimensions which it will be proper to assign to the shot. You understand that we have nothing to do here with projectiles weighing at most but half a ton.”
“Why not?” demanded the major.
“Because the shot,” quickly replied J. T. Maston, “must be big enough to attract the attention of the inhabitants of the moon, if there are any?”
“Yes,” replied Barbicane, “and for another reason more important still.”
“What mean you?” asked the major.
“I mean that it is not enough to discharge a projectile, and then take no further notice of it; we must follow it throughout its course, up to the moment when it shall reach its goal.”
“What?” shouted the general and the major in great surprise.
“Undoubtedly,” replied Barbicane composedly, “or our experiment would produce no result.”
“But then,” replied the major, “you will have to give this projectile enormous dimensions.”
“No! Be so good as to listen. You know that optical instruments have acquired great perfection; with certain instruments we have succeeded in obtaining enlargements of 6,000 times and reducing the moon to within forty miles’ distance. Now, at this distance, any objects sixty feet square would be perfectly visible.
“If, then, the penetrative power of telescopes has not been further increased, it is because that power detracts from their light; and the moon, which is but a reflecting mirror, does not give back sufficient light to enable us to perceive objects of lesser magnitude.”
“Well, then, what do you propose to do?” asked the general. “Would you give your projectile a diameter of sixty feet?”
“Not so.”
“Do you intend, then, to increase the luminous power of the moon?”
“Exactly so. If I can succeed in diminishing the density of the atmosphere through which the moon’s light has to travel I shall have rendered her light more intense. To effect that object it will be enough to establish a telescope on some elevated mountain. That is what we will do.”
“I give it up,” answered the major. “You have such a way of simplifying things. And what enlargement do you expect to obtain in this way?”
“One of 48,000 times, which should bring the moon within an apparent distance of five miles; and, in order to be visible, objects need not have a diameter of more than nine feet.”
“So, then,” cried J. T. Maston, “our projectile need not be more than nine feet in diameter.”
“Let me observe, however,” interrupted Major Elphinstone, “this will involve a weight such as—”
“My dear major,” replied Barbicane, “before discussing its weight permit me to enumerate some of the marvels which our ancestors have achieved in this respect. I don’t mean to pretend that the science of gunnery has not advanced, but it is as well to bear in mind that during the middle ages they obtained results more surprising, I will venture to say, than ours. For instance, during the siege of Constantinople by Mahomet II., in 1453, stone shot of 1,900 pounds weight were employed. At Malta, in the time of the knights, there was a gun of the fortress of St. Elmo which threw a projectile weighing 2,500 pounds. And, now, what is the extent of what we have seen ourselves? Armstrong guns discharging shot of 500 pounds, and the Rodman guns projectiles of half a ton! It seems, then, that if projectiles have gained in range, they have lost far more in weight. Now, if we turn our efforts in that direction, we ought to arrive, with the progress on science, at ten times the weight of the shot of Mahomet II. and the Knights of Malta.”
“Clearly,” replied the major; “but what metal do you calculate upon employing?”
“Simply cast iron,” said General
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