Five Weeks in a Balloon. Jules Verne

they laughed but half believed him; and he told them about Neptune where seamen get a hearty welcome, and Mars where soldiers hog the sidewalks to the point of tedium. As for Mercury, that’s a nasty world of bandits and merchants who are so similar, it’s hard to tell them apart.² And lastly he drew them a truly seductive picture of Venus.

      “And when we come back from this expedition,” said our genial storyteller, “they’ll award us that Southern Cross gleaming up there in the good Lord’s buttonhole.”

      “And you’ll have earned it!” the sailors said.

      So those long evenings in the forecastle went by, full of lighthearted chitchat. And meanwhile the doctor carried on with his educational talks.

      One day the conversation got around to steering balloons, and they invited Fergusson to give his views on the matter.

      “I don’t believe,” he said, “that we’ll manage to steer a balloon. I’m acquainted with all the methods attempted or proposed; not one of them has worked, not one of them is feasible. You can appreciate that I’ve had to spend time on this problem, that it was bound to be of great interest to me; but I couldn’t solve it with the means available from contemporary mechanics. We’d need to come up with a motor that’s both amazingly strong and unbelievably light! And if we did, we wouldn’t be able to withstand air currents of any significance! What’s more, until now we’ve been more concerned with steering the gondola than the balloon. That’s a mistake.”

      “But there are major similarities,” somebody countered, “between a lighter-than-air vehicle and a ship you can steer at will.”

      “No, there are few to none,” Dr. Fergusson replied. “The air has infinitely less density than the sea, in which a ship is only half submerged, while a lighter-than-air vehicle is fully immersed in the atmosphere and stays motionless in relation to the elastic fluid surrounding her.”

      “So you think the science of air travel has nothing more to offer us?”

      “Not at all! It just needs to look for different answers, so if you can’t steer your balloon, at least you can keep her in favorable air currents. The higher we go, the steadier they are in their speed and direction; they aren’t troubled anymore by the valleys and mountains that crisscross the earth’s surface, and these, as you know, are the main reason that the wind shifts and blows erratically. Now then, once these different zones have been identified, all the balloon will have to do is get situated in the currents that suit her needs.”

      “But in order to reach them,” Captain Pennet went on, “you’d have to go up and down continually. That’s the real difficulty, my dear doctor.”

      “And why, my dear commander?”

      “Let’s be clear on this: it would create difficulties and obstacles for journeys of long duration, if not for little day trips.”

      “And your reason, please?”

      “Because you rise only if you drop ballast and you descend only if you let out gas, and in the process your supplies of ballast and gas would soon be used up.”

      “My dear Pennet, that’s the heart of the matter. That’s the single difficulty science needs to go forth and conquer. This isn’t about steering a balloon; this is about moving her up and down without sacrificing the gas that’s her strength, blood, and soul as it were.”

      “You’re right, my dear doctor, but the problem still hasn’t been solved, the way to do this still hasn’t been found.”

      “Begging your pardon, it has been found.”

      “Who found it?”

      “I did.”

      “You?”

      “Otherwise, as you can appreciate, I wouldn’t have risked this balloon trip across Africa. I’d be out of gas by the end of the first day!”

      “But you didn’t say anything about this in England!”

      “No. I didn’t want to become embroiled in public controversy. It wouldn’t have served any useful purpose. I conducted my preparatory experiments in secret and to my satisfaction; so there was nothing more I needed to learn.”

      “Well, my dear Fergusson, can you let us in on your secret?”

      “Here it is, gentlemen—the way I do this is quite simple.”

      Audience interest was at its highest pitch as the doctor serenely took the floor, then spoke as follows:

      chapter 10

      Prior efforts—the doctor’s five tanks—the gas burner—the heating system—method of maneuvering—guaranteed success.

      “People have often attempted, gentlemen, to rise or descend at will without wasting a balloon’s gas or ballast. A French balloonist, Monsieur Meusnier, tried to achieve this objective by pumping air into a bag inside the envelope. A Belgian, Dr. Van Hecke, used wings and windmill blades to work up a vertical force that in most cases wouldn’t have been sufficient. The practical results achieved by these different methods have been unimpressive.

      “So I decided to tackle the problem more realistically. And at the outset I eliminated ballast from the equation, except in dealing with acts of God such as damage to my mechanism or the need to rise suddenly in order to dodge an unforeseen obstacle.

      “My method of ascending and descending involves nothing more than changing the temperature to make the gas expand or contract inside my lighter-than-air vehicle. And here’s how I achieve this result.

      “You saw several tanks brought on board along with the gondola, tanks whose functions are a mystery to you. There are five of them.

      “The first holds about 25 gallons of water, to which I add a few drops of sulfuric acid to increase its ability to conduct electricity, and I break it down using a powerful Bunsen battery. You know the gases that make up water: it’s two parts hydrogen and one part oxygen.

      “When the battery is in operation, the oxygen makes its way via the positive pole into a second tank. A third, positioned above the second and twice its capacity, receives the hydrogen reaching it via the negative pole.

      “Spigots—one with an opening twice as big as the other’s—put these two tanks in contact with a fourth known as the mixing tank. There the two gases we get by breaking down water are indeed mixed. The capacity of this mixing tank is about 41 cubic feet.¹

      “The upper part of this tank has a pipe made of platinum and equipped with a spigot.

      “You can already see what we have, gentlemen: the mechanism I’ve described to you is nothing less than a kind of blowtorch—it’s a burner fed by oxygen and hydrogen, and it’s hotter than a furnace in a foundry.

      “That settled, I’ll move on to the second part of the mechanism.

      “Two roughly adjacent pipes emerge from the lower part of my balloon, which is hermetically sealed. One comes from the upper reaches of the hydrogen gas, the other from the lower reaches.

      “These two pipes are equipped at various points with strong rubber joints, which allow them to flex as the vehicle shakes and shivers.

      “Both of them go down into the gondola and vanish into a cylindrical tank made of iron and known as the heating tank. Two strong disks of the same metal close it off at both ends.

      “The pipe from the balloon’s lower regions penetrates into this cylindrical container through its bottom disk; inside, it takes the form of a spiral-shaped coil whose rings rise one above the other, reaching almost to the top of the tank. Before emerging, the coil makes its way into a little cone whose convex base² is lowermost and looks like a bowl-shaped skullcap.

      “The second pipe emerges from the peak of this cone and makes its way, as I’ve told you, into the