The History of the Cannon

The resolutions passed at the last meeting produced a great effect out of doors. Timid people took fright at the idea of a shot weighing 20,000 pounds being launched into space; they asked what cannon could ever transmit a sufficient velocity to such a mighty mass. The minutes of the second meeting were destined triumphantly to answer such questions. The following evening the discussion was renewed.

The resolutions passed at the last meeting caused a great stir among the public. Timid people were frightened by the idea of launching a 20,000-pound projectile into space. They wondered what cannon could give such a massive object enough speed. The minutes of the second meeting would answer these questions triumphantly. The discussion resumed the following evening.

“My dear colleagues,” said Barbicane, without further preamble, “the subject now before us is the construction of the engine, its length, its composition, and its weight. It is probable that we shall end by giving it gigantic dimensions; but however great may be the difficulties in the way, our mechanical genius will readily surmount them. Be good enough, then, to give me your attention, and do not hesitate to make objections at the close. I have no fear of them. The problem before us is how to communicate an initial force of 12,000 yards per second to a shell of 108 inches in diameter, weighing 20,000 pounds. Now when a projectile is launched into space, what happens to it? It is acted upon by three independent forces: the resistance of the air, the attraction of the earth, and the force of impulsion with which it is endowed. Let us examine these three forces. The resistance of the air is of little importance. The atmosphere of the earth does not exceed forty miles. Now, with the given rapidity, the projectile will have traversed this in five seconds, and the period is too brief for the resistance of the medium to be regarded otherwise than as insignificant. Proceding, then, to the attraction of the earth, that is, the weight of the shell, we know that this weight will diminish in the inverse ratio of the square of the distance. When a body left to itself falls to the surface of the earth, it falls five feet in the first second; and if the same body were removed 257,542 miles further off, in other words, to the distance of the moon, its fall would be reduced to about half a line in the first second. That is almost equivalent to a state of perfect rest. Our business, then, is to overcome progressively this action of gravitation. The mode of accomplishing that is by the force of impulsion.”

“My dear colleagues,” said Barbicane, without further introduction, “we must now discuss the construction of the engine, its length, composition, and weight. We will probably end up making it enormous. But however great the difficulties, our mechanical ingenuity will readily overcome them. Please give me your attention, and do not hesitate to raise objections when I have finished. I do not fear them. Our problem is to give a shell an initial speed of 12,000 yards per second. The shell is 108 inches in diameter and weighs 20,000 pounds. “Now, what happens to a projectile launched into space? Three independent forces act on it: air resistance, the earth’s attraction, and the force that propels it. Let us examine these three forces. Air resistance is of little importance. The earth’s atmosphere extends no more than forty miles. At the given speed, the projectile will pass through it in five seconds. That is too brief a time for air resistance to be anything but insignificant. “Next, consider the earth’s attraction, or the weight of the shell. We know that its weight will decrease in inverse proportion to the square of the distance. When a body falls freely to the earth’s surface, it falls five feet in the first second. Suppose the same body were moved 257,542 miles farther away, to the distance of the moon. It would then fall only about half a line in the first second. That is almost the same as being perfectly still. Our task, then, is to overcome this gravitational pull progressively. We will do that by means of the propelling force.”

“There’s the difficulty,” broke in the major.

“That’s the problem,” the major interrupted.

“True,” replied the president; “but we will overcome that, for the force of impulsion will depend on the length of the engine and the powder employed, the latter being limited only by the resisting power of the former. Our business, then, to-day is with the dimensions of the cannon.”

“True,” replied the president, “but we will overcome that. The force of the blast will depend on the cannon’s length and the amount of gunpowder used. The amount of gunpowder is limited only by how much force the cannon can withstand. So today we must decide on the dimensions of the cannon.”

“Now, up to the present time,” said Barbicane, “our longest guns have not exceeded twenty-five feet in length. We shall therefore astonish the world by the dimensions we shall be obliged to adopt. It must evidently be, then, a gun of great range, since the length of the piece will increase the detention of the gas accumulated behind the projectile; but there is no advantage in passing certain limits.”

“Until now,” said Barbicane, “our longest guns have been no more than twenty-five feet long. So the size we must use will astonish the world. Clearly, we need a long-range gun. A longer barrel will keep the gas trapped behind the projectile for longer. But there is no advantage in going beyond certain limits.”

“Quite so,” said the major. “What is the rule in such a case?”

“Exactly,” said the major. “What is the rule in a case like this?”

“Ordinarily the length of a gun is twenty to twenty-five times the diameter of the shot, and its weight two hundred and thirty-five to two hundred and forty times that of the shot.”

“A gun is usually twenty to twenty-five times as long as the diameter of its shot. It weighs two hundred and thirty-five to two hundred and forty times as much as the shot.”

“That is not enough,” cried J. T. Maston impetuously.

“That is not enough,” J. T. Maston cried impulsively.

“I agree with you, my good friend; and, in fact, following this proportion for a projectile nine feet in diameter, weighing 30,000 pounds, the gun would only have a length of two hundred and twenty- five feet, and a weight of 7,200,000 pounds.”

“I agree with you, my good friend. In fact, using this proportion, a projectile nine feet in diameter would weigh 30,000 pounds. The gun would be only 225 feet long and would weigh 7,200,000 pounds.”

“Ridiculous!” rejoined Maston. “As well take a pistol.”

“Ridiculous!” replied Maston. “You might as well use a pistol.”

“I think so too,” replied Barbicane; “that is why I propose to quadruple that length, and to construct a gun of nine hundred feet.”

“I think so too,” Barbicane replied. “That’s why I propose making it four times as long and building a gun nine hundred feet long.”

The general and the major offered some objections; nevertheless, the proposition, actively supported by the secretary, was definitely adopted.

The general and the major raised some objections. But the secretary strongly supported the proposal, and it was adopted.

“But,” said Elphinstone, “what thickness must we give it?”

“But,” said Elphinstone, “how thick must we make it?”

“A thickness of six feet,” replied Barbicane.

“Six feet thick,” Barbicane replied.

“You surely don’t think of mounting a mass like that upon a carriage?” asked the major.

“You surely don’t plan to mount something that big on a carriage?” asked the major.

“It would be a superb idea, though,” said Maston.

“It would be a great idea, though,” said Maston.

“But impracticable,” replied Barbicane. “No, I think of sinking this engine in the earth alone, binding it with hoops of wrought iron, and finally surrounding it with a thick mass of masonry of stone and cement. The piece once cast, it must be bored with great precision, so as to preclude any possible windage. So there will be no loss whatever of gas, and all the expansive force of the powder will be employed in the propulsion.”

“But that’s impractical,” replied Barbicane. “No, I plan to sink the cannon into the earth, bind it with wrought iron hoops, and surround it with thick stone and cement masonry. Once the cannon is cast, its bore must be made with great precision to prevent any gap around the projectile. That way, no gas will escape, and all the powder’s expanding force will propel the projectile.”

“One simple question,” said Elphinstone: “is our gun to be rifled?”

“One simple question,” said Elphinstone: “Will our gun have a rifled barrel?”

“No, certainly not,” replied Barbicane; “we require an enormous initial velocity; and you are well aware that a shot quits a rifled gun less rapidly than it does a smooth-bore.”

“No, certainly not,” Barbicane replied. “We need an enormous initial velocity. And you know that a shot leaves a rifled gun more slowly than a smoothbore gun.”

“True,” rejoined the major.

“True,” replied the major.

The committee here adjourned for a few minutes to tea and sandwiches.

The committee took a short break for tea and sandwiches.

On the discussion being renewed, “Gentlemen,” said Barbicane, “we must now take into consideration the metal to be employed. Our cannon must be possessed of great tenacity, great hardness, be infusible by heat, indissoluble, and inoxidable by the corrosive action of acids.”

When the discussion resumed, Barbicane said, “Gentlemen, we must now consider what metal to use. Our cannon must be very tough and hard. It must not melt from heat, dissolve, or corrode when exposed to acids.”

“There is no doubt about that,” replied the major; “and as we shall have to employ an immense quantity of metal, we shall not be at a loss for choice.”

“There’s no doubt about that,” replied the major. “And since we’ll need an enormous amount of metal, we’ll have plenty to choose from.”

“Well, then,” said Morgan, “I propose the best alloy hitherto known, which consists of one hundred parts of copper, twelve of tin, and six of brass.”

“Well, then,” said Morgan, “I propose the best alloy known so far. It consists of 100 parts copper, 12 parts tin, and six parts brass.”

“I admit,” replied the president, “that this composition has yielded excellent results, but in the present case it would be too expensive, and very difficult to work. I think, then, that we ought to adopt a material excellent in its way and of low price, such as cast iron. What is your advice, major?”

“I admit,” the president replied, “that this composition has produced excellent results. But in this case, it would be too expensive and very difficult to work with. So I think we should choose a material that works well and costs less, such as cast iron. What do you advise, Major?”

“I quite agree with you,” replied Elphinstone.

“I completely agree with you,” said Elphinstone.

“In fact,” continued Barbicane, “cast iron costs ten times less than bronze; it is easy to cast, it runs readily from the moulds of sand, it is easy of manipulation, it is at once economical of money and of time. In addition, it is excellent as a material, and I well remember that during the war, at the siege of Atlanta, some iron guns fired one thousand rounds at intervals of twenty minutes without injury.”

“In fact,” Barbicane continued, “cast iron costs ten times less than bronze. It is easy to cast, comes easily out of sand molds, and is easy to work with. It saves both money and time. It is also an excellent material. I remember that during the war, at the siege of Atlanta, some iron guns fired one thousand rounds at twenty-minute intervals without damage.”

“Cast iron is very brittle, though,” replied Morgan.

“Cast iron is very brittle, though,” Morgan replied.

“Yes, but it possesses great resistance. I will now ask our worthy secretary to calculate the weight of a cast-iron gun with a bore of nine feet and a thickness of six feet of metal.”

“Yes, but it is very strong. I will now ask our respected secretary to calculate the weight of a cast-iron gun. Its bore is nine feet wide, and its metal walls are six feet thick.”

“In a moment,” replied Maston. Then, dashing off some algebraical formulae with marvelous facility, in a minute or two he declared the following result:

“In a moment,” replied Maston. He quickly wrote down some algebraic formulas with remarkable ease. A minute or two later, he announced the following result:

“The cannon will weigh 68,040 tons. And, at two cents a pound, it will cost—”

“The cannon will weigh 68,040 tons. And at two cents a pound, it will cost...”

“Two million five hundred and ten thousand seven hundred and one dollars.”

“$2,510,701.”

Maston, the major, and the general regarded Barbicane with uneasy looks.

Maston, the major, and the general looked at Barbicane uneasily.

“Well, gentlemen,” replied the president, “I repeat what I said yesterday. Make yourselves easy; the millions will not be wanting.”

“Well, gentlemen,” the president replied, “I repeat what I said yesterday. Don’t worry. The millions will be there.”

With this assurance of their president the committee separated, after having fixed their third meeting for the following evening.

With their president's assurance, the committee set their third meeting for the following evening and then dispersed.