1636: The China Venture

by Eric Flint

  “Well, we have another way of making a magnet. Here, let me show you.” Mike held up a cylindrical iron bar with bare copper wire wrapped around it so the loops were spaced apart.

  “We are going to pass a different kind of chi-energy, electricity—caged lightning—through this wire. That will cause the iron core to be magnetized. The electricity can’t pass into the iron core, because it is varnished.”

  Mike pulled out another mysterious object. “This is a Danielle cell; it’s a kind of battery. That is, it contains chemicals that react to make electricity, and we can carry it around to where we need it. It has two terminals. If we attach something that conducts electricity, like copper wire, to both terminals, then the electricity can pass out of the battery and then return. We call that an electric current.”

  Mike fetched a container of water and dipped his forefinger into it. “Here, touch both terminals simultaneously with a wet forefinger.” He demonstrated.

  Liu Rushi followed suit, and was startled when she received a small electric shock.

  “You just felt the electric current go through your finger. Not much current, of course, because this is a low voltage cell.”

  “What is voltage?”

  Mike thought for a moment. “Why does a river flow?” he asked her.

  “I suppose…because water flows downhill.”

  “Right. The difference in height between the upstream and downstream points is called the ‘head,’ and all else being equal, the greater the head, the greater the flow. Voltage drives electric flow just as head drives water flow.

  “Now, we come to something that’s tough to explain, but when a current moves through a wire, the wire becomes slightly magnetic. And if the wire is wrapped in a coil, then that reinforces the magnetic effect at the center of the coil. And that turns the core into a magnet.”

  “So the chi of the battery passed thorough the copper wire and into the iron core,” said Liu Rushi.

  “Well, it’s better to say that the electrical-chi in the copper wire caused changes in the iron core that made it like a south-pointing stone, that is, having a magnetic-chi,” Mike advised. “But only so long as the current goes through the wire. And the more powerful the battery, and the more turns in the coil, the stronger the electromagnet.”

  Liu Rushi studied the coil. “Then why didn’t you wrap more layers of wire around the core?”

  “Because this wire is bare. If the wires are touching, the current would get confused,” said Mike. “But if we used insulated wire—copper wire wrapped with silk or dipped in resin—we wouldn’t have to worry about the wires touching. We could add more layers for a given length of core and the electromagnet would be stronger. I’ll show you that, too.

  “Anyway, let’s get to the fun part. I am attaching a copper wire from the electromagnet to this switch. It has two positions, in one the current goes through and in the other it doesn’t. Like the lock on a dam. Then another copper wire from the switch to one terminal of the battery, and a third from the other terminal of the battery to the other lead of the electromagnet.

  “I am going to hold this iron nail near one end of the electromagnet. Please flip the switch and see what happens.”

  Liu Rushi flipped the switch and the nail leaped out of Mike’s fingers and clung to the electromagnet. Liu Rushi’s eyes widened.

  “Now flip it back.”

  The nail dropped off.

  “Now I’ll hold the nail further away, and you throw the switch.”

  Nothing happened.

  “This puny battery and this simple electromagnet don’t generate a strong enough magnetic field to pull the nail out of my hands at the longer distance. But why don’t I replace the bare wire electromagnet with a core of the same length and diameter, but wrapped in several layers of insulated wire.” He did so.

  “So, I have the same battery, and just about the same current—there’s a bit more resistance because of the additional wire—but I will have a much more intense magnetic field. Try the experiment again. Oh, and stay out of the path between the nail and the electromagnet.”

  Despite the greater distance, the improved electromagnet successfully summoned the nail.

  Liu Rushi clapped. “May I look at the second electromagnet more closely?”

  “Be my guest.”

  She held it up close to her eyes, turning it this way and that. “It looks like there’s a sheet of paper in between each pair of layers.”

  “That’s right. It provides a smooth surface for the outer layer to lie on. You want the windings to be as even as possible.”

  She handed it back to him.

  “Now comes the finale. I set the improved electromagnet vertically, like so, and prop it up. I put this copper ring on top, and then this narrower iron bar over the electromagnet, with their vertical axes aligned. Flip the switch on.”

  The copper ring jumped into the air, traveling along the second bar until it struck Mike’s hand.

  “Marvelous!” said Liu Rushi.

  Mike bowed. “There are two things going on here. First, a changing magnetic field induces an eddy current in a closed-loop conductor, like this copper ring. The magnetic field is zero when the switch is in the off position, and strong when the switch is in the on position. So there is a change in the intensity of the magnetic field, and a transient current in the copper ring in response to the change.

  “Secondly, the current in the ring creates its own magnetic field, but for reasons that it would be too complicated to explain, its magnetic field opposes the first one—as if you put two magnetized needles next to each other with their south poles pointing toward each other. So the ring and the electromagnet repel each other, just as those two needles would.

  “The repulsion is brief, because the current in the ring is transitory. But that’s enough to launch the ring into the air.”

  “Let’s do it again,” said Liu Rushi, and they did.

  “Is there a way to suspend the ring in the air, like a balloon?” she asked.

  “Yes and no. The current from the battery is constant. To have a constant repulsive force on the ring, I would need a continually changing current, so I had a continually changing magnetic field in the core. And I would have to adjust the level of the current so the magnetic repulsive force just balanced the force of gravity. But setting that up is an experiment for another day. I know that Jim is planning to do a lecture-demonstration on electricity, and that would be nifty.”

  Jim looked up. “You could also forget about the ring and just use a metal coin. Put the electromagnet so it is above the coin and attracting it upward, and adjust the current so the upward force is enough to counterbalance gravity. Back up-time, I mean, back home, there were toys that had light cells to sense whether the object was rising or falling and correct the current so that the coin would be levitated.

  “You should also tell her that we can make electricity in other ways than batteries. For example, we have pedal generators. I am planning an electrical show—it will include the jumping ring trick—and we’ll hire a bunch of laborers to pedal like crazy for an hour so we have plenty of electricity to play with. And if we had a permanent installation, we put in a windmill or a steam generator.”

  “I never know when you’re listening and when you aren’t,” said Mike.

  “Why would I interrupt your date?” Jim replied.

  Suddenly, they heard the great bell tower of Hangzhou tolling the time.

  “Oh my,” said Liu Rushi. “It’s later than I thought. I must go; I have an engagement. Thank you, Mike; please give Madam Saluzzo my apologies. I will come back as soon as I can to hear what she wanted to tell me.”

  “Yes, please come again,” said Mike.

  Liu Rushi’s houseboat

  Hangzhou

  It seemed crazy. Only yesterday, Liu Rushi couldn’t stop thinking about her lover from Songjiang, her “Wozi,” the poet Chen Zilong. Every day since the young poet had left her, she had written a ci, a song-poe
m, about her loneliness.

  Today she had written,

  He is gone.

  Gone from the jade pool.

  It was a reference to his Fu poem, “Picking the Lotus.” He had written it in a better time, when their love was young and untroubled, before he had taken and failed the provincial examination.

  So far so good. But then her inspiration had faltered. Instead, she found herself thinking about her ride in the balloon…and her fellow rider.

  She mentally berated herself for her fickleness. It had only been a month since her lover of two years had abandoned her, at the behest of the grandmother who had raised him.

  Like many women, Liu Rushi had read and reread Tang Xianzu’s opera, The Peony Pavilion. Unlike most women, she had performed in it. Oh, how she enjoyed playing the role of Du Linang, the official’s daughter who dreams of the scholar Liu Mengmei, imagining their passionate affair. Her dream is interrupted and, without ever meeting him in the waking world, she pines for him and dies of lovesickness. She then seeks him out in his dreams and, three years later, is brought back to life. Liu Rushi had fancied herself as committed to love as Du Linang had been.

  No, she must think of Chen Zilong, and not of Mike Song. She rubbed her ink stick on the well of her ink stone, until the water in the well was black, and then she dipped her bamboo brush into it and wrote:

  I feel frail, lighter than a swallow.

  That was a good metaphor. A swallow had delicate bones, easily broken. A metaphor appropriate for a self that was broken.

  So why did she suddenly think about what it was like to fly like a bird above the city of Hangzhou?

  And why did that thought bring a smile, however brief, to her face?

  Enough! It was time, past time, to go to sleep.

  The Glorious Exhibition Gift Shop

  “Oh, by the way, Martina, did Liu Rushi happen to stop by?” Mike’s tone was elaborately casual.

  Martina fought back a smile. “No. But a letter was delivered to you. And it’s scented.” She reached below the sales counter. “Here you go.”

  Mike broke the seal, and unfolded the letter. “I am invited to meet her for tea tomorrow afternoon at a particular teahouse in Longjing Village. She drew me a map, too, so I can find it. It looks like it’s in the hill beside West Lake.”

  “Don’t be late,” said Martina.

  “Not a chance!”

  Chapter 31

  Longjing Village

  The next day, Mike Song and Liu Rushi were sitting in a teahouse in a village near Hangzhou. From where they sat, they could see the terraced hill behind the village, with men and women in straw hats picking tea leaves.

  “So this is Longjing tea,” said Mike, tea cup in hand. “The most famed of all the varieties of tea.”

  “Not just that, but the superior grade, the best of the best. It was picked before the Qingming festival, and thus from the youngest, tenderest shoots.” The Qingming festival was on the first day of the fifth month, early April. “And we are drinking it from a Yixing clay teapot, just as a connoisseur would drink it.”

  “I never imagined I would be sipping tea in Hangzhou with a tea connoisseur,” said Mike. “Actually, I never imagined I would be in Hangzhou at all.”

  He picked up the tea jug and was about to pour some tea into a drinking cup for Liu Rushi, but before he could do so, she cried, “Stop!”

  He raised his eyebrows. “What’s wrong?”

  “We should breathe in its famous aroma first,” said Liu Rushi. “Please fetch the scent cups.” She gestured toward a side table. “They are over there.”

  Mike handed them to her.

  “Allow me,” said Liu Rushi. She poured the tea into the scent cups and then placed the drinking cups upside down over them. “We call this ‘the dragon and phoenix in auspicious union.’ It is a sort of prayer for our future happiness.”

  Then she inverted the cups so the drinking cups were right side up and the scent cups upside down, transferring the tea into the drinking cups. “The carp turns over,” she announced.

  Finally she removed the scent cups. “Please receive the fragrant tea,” she declared. “Sniff the inside of the scent cups, then drink the tea. Preferably, in three sips.”

  Mike did so, and then Liu Rushi did the same. They leaned back contentedly. After a time, Mike said, “Shall we go sit by West Lake?”

  “That sounds delightful,” said Liu Rushi.

  Mike paid off the tea shop proprietor, and Liu Rushi boarded her sedan chair. It was of the closed variety, with a pointed roof, windows on four sides, and doors on two sides. “Would you like to come inside?” she asked.

  Mike shook his head. “I’ll walk; I need the exercise.”

  Her two porters heaved up the sedan chair and they started walking downhill. Arriving at the shoreline, Liu Rushi put her head out the window of the sedan chair. “If you don’t mind some more walking, Mike, I would like to go to the Flowery Harbor.”

  “That’s fine with me.”

  They continued on, and at last Liu Rushi thumped the ceiling of the sedan chair to signal that they had arrived at her destination. Her porters gently lowered the sedan chair, and she stepped out. Lashed behind the chair, there was a basket with a latched lid, the equivalent of a car trunk. She opened the basket and took out art supplies.

  Mike saw that they were at the southern end of the Su Causeway. A stream flowed down from Huajia Hill, and many flowers were on its banks where it met the lake. In the lake itself, there were many lotus pads floating, and the lotuses were in bloom. Studying the scene more closely, Mike caught fleeting glimpses of goldfish and carp as they swam close to the surface.

  “Isn’t it beautiful here, Mike?”

  “Very much so.”

  “I am going to make a modest painting, but I need something in the foreground. Why don’t you sit here?” She pointed to a spot near the water.

  “Okay. Like this?”

  “Wait.” She came over and adjusted his head position. He shivered under her touch. “Hold yourself just so, please. I’ll be done in a few minutes.”

  She squatted down on the grass and ground a black ink cake on her ink stone with a little water. When she was satisfied with the consistency, she dipped in her brush, and started painting.

  After a few moments, she told him to relax, which he did so with relief. “May I look at your artwork?”

  “Soon, Mike. I sketched you in quickly, so you could relax, but that doesn’t mean it’s ready to be viewed.”

  He walked down to the water’s edge, and found an area where the water was only a few inches deep, and clear. He moved his hand across its surface, creating ripples. Then he studied the reticulated lines of light on the lake bottom. What were those called? he mused. “Oh, caustics.” He had read about them in his computer graphics course.

  As Mike dawdled by the water, and Liu Rushi worked on her painting, Mike told her, “You know, we have two artists on our staff, Judith Leyster and Zacharias Wagenaer. I can introduce you, if you like.”

  “Please do,” she said. She set down the brush she had started with and picked up another. Some minutes later, she set down her tools.

  “Now you may look, Mike.”

  He studied the scene. The picture was monochromatic, in the style that, according to his aunt’s coffee table book on Chinese painting, was called “ink and wash.” Insofar as the scenery was concerned, it was moderately true to life, but he was drawn wearing an antique costume.

  “Which dynasty is this outfit from?” he asked.

  “The Song. I used you to represent the official Yun Sheng, who had a private garden here, and raised five-colored carp. Of course, since the painting is monochromatic, the colors must be in your mind.”

  “The picture is lovely.”

  “I am glad you think so, because it is a present for you. I hope you will find it as enjoyable to look at as I have the images in the kaleidoscope you gave me.”

  “I will hang it where
I can see it every morning,” Mike assured her. He gulped, and added, “When may I see you again?”

  “Would you…would you like to dine with me tomorrow evening, on my house boat?”

  “Just tell me where and when.”

  Liu Rushi took out a fresh sheet of xuan paper from her carrier and wrote upon it. “Here are the directions; it is moored on the Grand Canal. Be there at the start of the Hour of the Dog.” That was 7:00 p.m.

  Mike thought about kissing her, but he knew that even in twentieth-century China, public displays of affection were frowned upon. His parents, and his aunt and uncle, had mentioned how shocked they were when they came to America.

  As these thoughts passed through his mind, the opportunity, if it in fact had existed, passed by. At a gesture from Liu Rushi, the porters helped her into her sedan chair. She poked her head out, and said, “I will count the moments until I see you.” The door of the sedan chair closed.

  Mike watched as the sedan chair bearers ambled away. The flowery goodbye might, he supposed, be common in literary circles in seventeenth-century China, but he was inclined to believe, or at least hope, that it was more personal and heartfelt.

  The next day, on Liu Rushi’s houseboat

  Grand Canal

  Hangzhou

  “Everything must be perfect, Peach,” said Liu Rushi. “Have you swept the floors?”

  “Yes, mistress,” said her maid.

  “Are the chairs in the parlor arranged the way I like them? Are my instruments set out on the side table?”

  “Of course,” said Peach. “You seem a bit…on edge. Is this ‘Master Song’ a high official just come to Hangzhou?”

  “Not an imperial official,” said Liu Rushi, “not even a district magistrate. He has some sort of position with the embassy sent by the barbarians who call themselves the ‘United States of Europe.’”