1636: The China Venture

by Eric Flint

  “At this height, about thirty-five to forty miles,” said Mike.

  “That far? That’s further than a regulation day’s march for an army!”

  “And how would you know?” said Mike. Instantly, he regretted the sharpness of the question.

  Her lips compressed into a thin line. “You think a woman can’t be interested in military affairs?”

  “Of course she can,” Mike acknowledged. “It’s just not a common interest.”

  “Well, my interests are admittedly more in cultural pursuits—I read classic literature, write poetry and do calligraphy and painting—but I have read some books about the art of war. Certainly enough to know that it would be very handy for a general to see his enemy coming when they are still that far away. Why, if Han Shizhong and Liang Hongyu had one of these balloons at the Battle of Huangtiandang, the Jin Navy wouldn’t have been able to escape Han’s trap by digging a canal.”

  “I have not heard of that battle,” said Mike.

  “It was five hundred years ago, during the Jin–Song wars. The Song were fighting to hold the Yangtze River line. Liang Hongyu directed the battle with her drums.”

  “Her?”

  “Yes, ‘her.’ She was a great general, she held the title of ‘Lady Protector of the Nation.’”

  “Anyway, your comments on the military value of balloons were well taken,” said Mike. “In fact, American and European armies used to use balloons for observation purposes.”

  “Who are the Americans you speak of? And Europe, I have heard that is the place the Christian priests came from, but in all the years they have come to our shores, none has flown through the air, until you came.”

  “The explanation is complicated,” said Mike.

  “I see no one rushing us to go somewhere else. Please explain.”

  “Well, it’s something of a secret.…”

  “I have kept many secrets.”

  “Okay. America is a land further west even than Europe, across another ocean. Some Europeans went there to live, and built a new nation. Three of my fellows are from that nation; I came there from Formosa to study their science.”

  “Formosa? It is mostly a land of jungle and headhunters, from what little I’ve heard about it.”

  “Well, in my time, it was settled by Chinese.”

  “I don’t understand.… Your time?”

  “My American friends are from a town called Grantville. And I was in that town when it was moved from the future to this time, and from America to Europe.”

  Liu Rushi pouted. “Now you’re making fun of me!”

  “I’m serious. That’s why we can fly through the air and stuff like that; we have the advantage of four centuries of study and experimentation over everyone from this time.”

  “The Buddhists have stories about people traveling into the future, but I have never heard of one traveling into the past.”

  “Well, we have no idea how it happened; it was done to us.”

  The balloon was tethered, but the clouds in the sky weren’t. Engrossed in conversation, Mike hadn’t noticed that one cloud in particular had been getting closer. Suddenly, they were in its shadow. The balloon gradually started to ascend.

  Liu Rushi grabbed Mike’s arm. “What’s happening? You didn’t do anything to make us rise!”

  “Don’t worry,” said Mike. “Hot air rises, cold air sinks. The cloud is now shading the air around us, so it’s getting cooler. The fabric of the balloon doesn’t conduct heat well, so the air inside is still hot. The temperature difference between balloon and outside air is thus increased, and so we have more lift. If the cloud stays above us, eventually the air in the balloon will cool off a bit, too, and we’ll stop ascending. Before we reach the end of the tether, I’m sure.” Mike made no effort to disentangle himself from Liu Shi’s grasp. But a few seconds later she freed herself.

  Liu Shi leaned over the basket, looking north. “Could that be Lake Tai, way in the distance?”

  Mike triggered the burner for a short burst, and the balloon, which had been slowly sinking, ascended once again. “How far away is that?”

  “Perhaps thirty miles to the south coast, around Huzhou. Perhaps another thirty to the north coast, around Wuxi.”

  “All I see is a bright sliver on the horizon. That could be sunlight glinting off water, I suppose. We are high enough to see the southern portion, if the air is clear. But our tether isn’t long enough to let us see the whole lake.”

  Liu Rushi turned to face Mike, giving him a megawatt smile. “Oh, it’s so beautiful and quiet up here. I wish we could untie the tether, and float up like a cloud! Go high enough to see the Southern Capital, Nanjing!”

  “I would like to ‘free balloon’ in China, one day,” Mike admitted, “but first we would have to have officials send warnings to people for fifty miles around. So they wouldn’t think the balloon was some kind of aerial demon. The American history books say that when Jacques Charles made the first flight in a hydrogen balloon—hydrogen is a gas that wants to rise even more than does hot air—he landed sixteen miles away. The farmers that saw the balloon fall came to investigate, and the gas inside the balloon made its skin move, as if it were a living thing. Thinking it was a monster, they attacked it with their pitchforks. The government had to tell all of the villages near the capital that the balloon was a mere machine that could fly through the air, and they were to leave it alone in the future.”

  Liu Rushi looked disappointed. “Is fifty miles the furthest a balloon can fly?”

  “Oh, no,” said Mike. “It depends on the wind, of course, which is stronger the higher the balloon climbs, and how long the balloon stays up. A hydrogen balloon can stay aloft longer than a hot air balloon, and a large balloon longer than a small one. But I was told that a balloon only a bit larger than this one, the Great Balloon of Nassau, went a mile up, and flew five hundred miles in eighteen hours. And that was only about fifty years after the very first balloon flight. I think that balloon used coal gas; it has more lift than hot air and less than hydrogen.”

  Liu Rushi’s eyes were wide. “So you could fly from here to the Three Gorges of the Yangtze, or to Beijing and the Great Wall of the North!”

  “Well, you could,” Mike admitted, “but only if the wind were blowing the right way.”

  “Couldn’t you use sails?” she asked. “I know that ships can sail in a direction other than the way the wind is blowing.”

  Mike shook his head. “That’s possible because ships are half in the water and half in the air. The wind blows on the sails, but sails are connected by the masts to the hull, and the hull resists the movement. It feels both a force from the air and a force from the water, which may act in different directions depending on how the yards are laid and where the bow points. If the sails are at the right angle to the hull, the ship can go in a direction somewhat askew from the wind direction.

  “But this balloon is sailing only in the air. If we were to cut the tether while the balloon was feeling a wind, the balloon would move faster and faster. But it feels only the one horizontal force, the wind, and thus goes just downwind. And as it got faster, the apparent wind on it would be less and when it was moving at the same speed as the air, it would feel no wind at all.”

  “How sad,” said Liu Rushi, shaking her head. “To someone on the ground, a balloonist seems like an immortal, able to ascend into the heavens. But you are at the mercy of Fei Lian, the wind god.”

  “Well, yes. But the wind not only strengthens as you go higher, it changes direction. So you can go in a particular direction, if you are able to change your altitude sufficiently. Unfortunately, on a hot air balloon, how high you can go for how long depends on how much burner fuel and ballast you’re carrying. Also, we can do a little bit of steering away from downwind by letting hot air out of one side of the balloon, or by dragging a rope on the ground—the rope then acts a bit like the hull of a ship in the water; there’s resistance.”

  Liu Rushi pointed to the eas
t. “Speaking of ships, I can see a big barbarian ship over there.”

  Mike shaded his eyes against the sun. “That’s the Groen Feniks. It’s one of our two ships, the smaller one.”

  “I just had a crazy idea,” said Liu Rushi.

  “Oh, what’s that?”

  “It’s absurd…”

  “Please tell me.”

  “Well, you were talking about how ships sail off the wind because they have sails in the air and hulls in the water.”

  “Yes, go on.…”

  “Suppose you could cut a ship in half, and put the sails way up in the sky, attached to a balloon, and leave the hull in the water. But there was a big strong tether between the balloon and the hull. It would be neither a bird nor a fish, yes? The wind would act on the sail, which would act on the balloon, which would act on the tether, which would act on the hull, the water fighting against it.”

  “I think…” said Mike. “I think you really are quite clever. You would need a very strong tether, though. I don’t know whether we could build one that strong, and you would also want a very simple hull, since its only purpose would be to feel the resisting force of the water; all the people would be in the basket of the balloon. You just need some mechanism to move the rudder of the water hull. Oh, forget the sails; they just add weight without adding lift, and the balloon itself would act as a sail.”

  “Really? You think it would work?”

  “I think the underlying physics is valid, though I’d want to ask Jim. I don’t think we have the materials yet for making the tether or the hull. But it’s an interesting idea.”

  Liu Rushi preened.

  “I suppose I should tell you that back home, we have something better than a balloon: an airship. It has engines that push it in a particular direction, even if there’s no wind at all.”

  “Engines? That is something like oars?”

  “Well, I’d have to show you. We don’t have a full-size airship here in China, as we do back in Grantville, but I have a little model of one. Would you like to see it?”

  She smiled at him. “Very much so.”

  “Well, then please come to our exhibit hall. Which reminds me—can you help me with this?” Mike held up a folded banner. “There’s almost no wind now, so we want to hang it over the side.”

  “If you wish,” said Liu Rushi. “What does it say?”

  “‘Come See the Glorious Exhibition of Marvels of the Uttermost West on Hefang Street near Wu Shan Hill.’ That’s where you’ll find me, of course.”

  The wind started to pick up as the morning progressed, and Mike began the descent. That pretty much meant increasing the spacing between burns, and making the burns shorter.

  When they got close to the ground, Mike tossed over a trail rope. The balloon only felt the weight of the part of the trail rope that was in the air, not the part lying on the ground, so it provided some buoyancy control. If the balloon tried to rise, it would have to lift more rope.

  When the basket was just a foot or two off the ground, the ground crew rushed in to grab onto the rail and lash on additional ropes. “Please wait, Liu Rushi,” Mike said.

  Mike opened the basket door, and jumped down. There was a little lurch but the change in weight was compensated for by the ground crew, the new ropes, and the trail rope.

  “Put your hands on my shoulders and I’ll lift you out,” said Mike.

  Liu Rushi complied. Mike put his hands on her waist, and brought her gently down to Earth.

  “Fly again sometime?” Mike asked.

  “Definitely.”

  Chapter 30

  Glorious Exhibition Gift Shop

  “Hello, Mike,” said Martina Goss. “Who’s the young lady?” Liu Rushi, this time, was dressed as an elegant woman.

  “Her name is Liu Rushi,” Mike told Martina. “She’s a calligrapher and a painter, and she liked the balloon ride and wanted to know more about our gadgets.” He then bowed to Liu Rushi. “I was hoping you would come.”

  “After riding in your balloon, how could I resist your promise to show me additional wonders?”

  Martina offered Liu Rushi her hand. “Pleased to meet you. I am Martina Goss.”

  After a moment’s pause, Liu Rushi took it and bowed. “The pleasure is mine. You are his wife?”

  “Oh, no,” said Martina. “Mike’s not married. My husband is Jim Saluzzo.”

  “Where’s Jim?” Mike asked.

  “In the back room, tinkering with an exhibit that stopped working. Why do you ask?”

  “No special reason. I’m just giving Liu Rushi the grand tour. How is business?”

  “We’ve had a run on kaleidoscopes.”

  “If you have any left, I’d like one for Liu Rushi. Please put it on my account.”

  Martina studied Liu Rushi more closely, then said, “Not a problem. What do you intend to show her?”

  “Well, to start off with, my model airship. Wait here, Liu Rushi, it will just take a moment for me to fetch it.”

  As Mike rummaged in a back room, Martina and Liu Rushi made small talk.

  At last Liu Rushi said, “Would you mind if I asked you a more personal question?”

  “Ask away,” said Martina. “I don’t promise to answer it, however.”

  “I understand that you are married to Jim Saluzzo, and you are dressed just as the wife of a scholar-official should be dressed. But here you are working in a shop, speaking with any man that enters. How is that proper?”

  “First of all, this is not an ordinary shop. This is a part of our exhibition of the technological achievements of Grantville. We don’t just want the Chinese intelligentsia to marvel over our gadgets; we want to be able to sell them in China, so we can buy Chinese things. There are only four people from Grantville in the mission, and we all have to do our share to encourage an interest in those gadgets.

  “And secondly, it’s not at all unusual for women to run shops in Grantville, or for men and women to talk to each other.”

  “How refreshing,” said Liu Rushi.

  Just then, Mike returned. “Here it is!” he said. What he held was a roughly elliptical model blimp, a few feet in length and perhaps a foot in diameter. At least, those would be its dimensions if it were inflated, which it wasn’t.

  “So I made the envelope for this from material left over after our hot air balloon envelope was cut and sewn for us. I scavenged the fins, rudder and propulsion and control system from a broken model airplane that my uncle gave me.”

  Mike held up a small radio transmitter. “It’s radio controlled. If I turn this on, you’ll see the propeller turn on my makeshift gondola.” He held up the gondola, and demonstrated this. “The gondola has the radio receiver, the motor, and the propeller, and a line to control the rudder. I attach the gondola and rudder and inflate the envelope. When I send the signal, the propeller pulls the airship through the air, so, unlike a balloon, it can go somewhere even if there’s no wind. I am lucky that the RC unit had rechargeable batteries, and that they are still holding a charge.”

  Liu Rushi looked very confused.

  “Mike, you’re throwing too many new concepts at her at one time. Radio? Propellers? Batteries? Come on!” said Martina. “Have mercy on the poor girl.”

  “My apologies, Liu Rushi. I should start by showing you something simpler, and save the airship for another time. It’s not as though I can inflate it now, anyway. We’d have to go find some deserted place to do that.”

  “You wish me to go with you to some deserted place?” Liu Rushi asked. She winked at Martina.

  “Uh, I didn’t mean it that way,” Mike stammered. “The model airship is much smaller than the balloon I took you up in; it’s only a few feet long. The lift is proportional to the volume but the weight is proportional to the surface area. So for the model airship to ascend, I have to use a more potent lift gas than hot air: hydrogen.”

  “What is that?” asked Liu Rushi.

  “It’s a gas that’s lighter than air. Unfortun
ately, if it mixes with air in the wrong ratio, it can burn, even explode. That’s why we have to go out to the middle of nowhere.”

  Liu Rushi stifled a laugh. “You are in Hangzhou, one of the Middle Kingdom’s largest cities. And it is in one of the most populous provinces. You would have to go to one of the islands way out in Hangzhou Bay, or perhaps up into the mountains. A long trip, either way.”

  “I’ll have to do it at some point,” said Mike. “We want to show this model airship to the emperor, if we ever get an audience with him. And we want to make sure it still works right after traveling halfway around the world.”

  “Show her some simple electrical gadget,” Martina suggested.

  “Hey!” said Mike. “I can set up a battery and electrodes and split water into oxygen and hydrogen.”

  “No hydrogen,” said Martina.

  “Just a test tube worth?” Mike pleaded. “Even if you put a match to it, it would only make a little pop.”

  “Not here. Not indoors, and not in the courtyard either.”

  Mike made a face. “All right.… Hmm.… I guess I can do something with electromagnets.… Hey, Liu Rushi, let me show you the ‘jumping ring’ trick.… Follow me.…” And he rushed off into another room.

  “Geeks will be geeks,” said Martina. “Please follow him and make sure he doesn’t blow up the place. And come to think of it, I have something to show you myself, given your background. Come to speak to me when you and Mike are done.”

  In the backroom, Mike introduced Liu Rushi to Jim Saluzzo, who grunted and continued what he was doing, which was building something.

  “I’m sorry,” he told her, “Jim seems to be a bit preoccupied.”

  “It is the creative trance,” she said. “I am familiar with it.”

  Mike nodded. “Anyway, I know that Chinese scholars know about magnets—stones that attract each other, and which if shaped into a needle and allowed to float on water, will align north-south.”

  “Of course,” said Liu Rushi. “They are first described in…let me think.…” She frowned prettily. “The Book of the Devil Valley Master. We call the stones ‘loving stones’ or ‘south-pointers.’ You can use them to pick up an iron needle, and the best stones can pick up a string of ten needles hanging end to end. And the Dream Pool Essays say that you can rub an iron needle with them, and the chi-energy of the stone will be transferred to the needle.”