“It could well be our fugitives,” Ragnar said, turning to Harald.
“It could be any group of adventurers,” Harald said. As determined as he was to find the foreigners and learn the secrets of their sky ships and weapons, he was wary of attempts to take advantage of his intentions. “I hope you’re not expecting a reward for this, Korr?”
“Well,” Korr said. “No. That is, I wasn’t going to tell you at all. Thought it was strange, is all. But then I was at the inn at Hedeby, talking it over with some of my business associates. You know, the way you talk, sometimes, with business associates, and this man at the next table, he keeps leaning over, like he’s listening in. Big tall fellow, wearing the hood of his cloak pulled over his head indoors, like maybe he’s one of them lepers in the Bible. I don’t think much of it, but when I leave, this fellow follows me outside. Tells me he’s interested in my story, says he’ll give me a silver if I tell him everything I know. So I tell him. Mind you, this fellow is strange. Raspy voice, barely speaks a word of Frankish. I know a little of every language anybody speaks in this region, and this fellow didn’t know any of them. Twenty words of Frankish, maybe. But he makes it clear he wants to know about these people in Normandy.”
“Who was this man?” Harald asked.
“I don’t know. Didn’t get his name. Never saw his face. Anyway, I tell him what I know. I mean, who wouldn’t, for a silver? And then do you know what he tells me? He tells me I should come tell you. Says King Harald would be very interested to know about these people. Offers me twenty more silver to make the trip. I had a knarr leaving for Uslu in the morning, so I hitched a ride. And here I am.”
Harald learned forward. This man’s story had piqued his interest. “This stranger paid you to deliver this information?” he asked. “Why?”
“Well, my lord, I suppose you would have to ask him. I’m sorry, he asked me to speak with you first, as he’s not much of a talker. He’s waiting outside.”
Chapter Thirty-six
The raid on Rouen netted them easily ten times the spoils they’d amassed so far. In addition to nearly two hundred silver coins, they acquired candlesticks, tapestries, furs, jewelry and a great number of other items. It was enough to pay off their debt to Hrólfr and then some. They didn’t give it to Hrólfr right away, though, as Sigurd didn’t think it wise to let on that it was they who had executed the raid. Gabe and Reyes agreed: if Hrólfr got the idea that the newcomers possessed weapons capable of breaching stone walls, they might find themselves pressed into service for him. Hrólfr seemed to be a more honorable man than Harald, but there was no point in tempting him.
Bylgjasverð had been chased downriver by ships from Rouen, finally losing them in the dark some distance out to sea. Once she’d lost her pursuers, she turned around and headed west, raiding along the coast for the next two days. She returned with a modest haul, which was added to the spoils from Rouen. Then a payment was made to Hrólfr, under the pretense that the spoils had been acquired by Bylgjasverð. Most of the loot was held in abeyance, and anything that could easily be traced to Rouen was hidden or—in the case of the chalice and candlesticks taken from the cathedral—melted down. The balance of their debt was paid off in several installments over the next few weeks.
The raid on Rouen had been so lucrative that many of the men who had intended to return to Norway in the fall agreed to pay to stay through the winter, presumably in the expectation of more such raids. Sigurd did what he could to temper their hopes, but they had seen what the foreigners could do, and were convinced that great wealth would soon be theirs. Raiding continued through the summer, but the Norsemen relied on conventional methods to avoid attracting unwanted attention. Hrólfr made it clear that he suspected the foreigners had been involved in the raid on Rouen, but he didn’t ask and they didn’t tell.
The spacemen were, in any case, too busy with other tasks to manufacture explosives. Gabe and O’Brien were working with a crew of Norsemen on the guard tower while Reyes spent her time trying to reestablish contact with Andrea Luhman. She now had less than two weeks until Andrea Luhman would be in range again, and she wanted to be ready.
She soon realized that building the transmitter was going to be the easy part. The real challenge was powering it. That required first building a battery or, at the very least, a capacitor and some sort of generator. She had most of the raw materials, but fabricating the components under the current conditions was daunting. At the very least, she was going to need a forge of some kind, and some metalworking tools. Experimentation told her it would take two weeks just to build the batteries, and she was dubious she’d be able to stack enough cells to generate the sort of voltage she’d need to power an arc gap transmitter, which meant she’d also need to build a transformer or boost converter.
If she had a general idea where Andrea Luhman would be, she could build a directional antenna that would use far less power. But that was the problem in a nutshell: the range of the suit radios was so limited precisely because they sent waves out in all directions. She could probably rig something up to channel the suit radio’s transmission in a particular direction, but it still wouldn’t be powerful enough to cut through the noise of the atmosphere. If Andrea Luhman knew where to look, it could point its antennas toward the signal and pick up enough for them to communicate, but the lander’s crew were several hundred kilometers southwest of the crash site. It would be a miracle if Andrea Luhman found them.
No, it was time to rethink the problem. Twenty-third century solutions weren’t going to cut it. Forget converting an electrical current to radio waves. She needed something simpler. She didn’t need to communicate a lot of data; she’d assumed the arc gap transmitter was only going to be good for Morse code anyway. Really all she need to communicate their location: a beacon indicating that the crew was still alive. Once Andrea Luhman’s crew had that information, they could work out a better method of communication.
The obvious answer was a signal fire. But it would have to be a hell of a fire, and even then it wouldn’t attract the attention of anyone on Andrea Luhman unless she had some way of modulating the intensity to make it flash or flicker. A heliograph—mirrors angled to reflect sunlight—was another possibility, but again they would need to have a general idea where Andrea Luhman was in the sky. If its orbit was low enough, they might be able to spot it at night—but that wouldn’t help with a heliograph.
She came back to the idea of a fire, bright enough to be seen from space, but small enough to cover temporarily with a shutter of some sort. A magnesium fire would do it. She walked from her makeshift work area to where O’Brien and Gabe were placing posts for the watchtower. O’Brien, still not up to performing heavy labor, spent most of his time offering advice and making bad jokes.
“O’Brien,” she said, “if I wanted a large supply of magnesium, where would I find it?”
“Pure magnesium?” O’Brien said, looking up from the post Gabe was placing. “Not going to happen. But it’s relatively easy to extract from salt water. What do you want magnesium for? I thought you were building a transmitter.”
“I am,” Reyes said. “I’ve just moved down the wavelength spectrum a bit.”
It took O’Brien a few seconds, but then he smiled. “You’re transmitting light.”
“That’s the idea. A magnesium fire should be visible from space, right?”
“Not exactly my area of expertise, but I’d think so. A big enough one, anyway.”
“How big? A meter in diameter?”
“Les than that, I would think. If you knew the exact luminosity, you could figure the dispersal with the inverse square rule, but even then you’d have to take into account the atmosphere and a lot of other factors. Like I said, not my area of expertise. But unless they happened to be looking in the right place at the right time, they’d still never see it.”
“I’m thinking some kind of shutter system, to make the light flash.”
O’Brien nodded, rubbing his chin. “O
r, instead of one fire, a bunch of fires in sequence.”
“What do you mean?”
“Dig craters in the ground, a meter wide. Join them with a fuse, like the one we used for our black powder bomb. Put enough magnesium in each of them to burn for a few seconds. One fire goes out, the next one lights up. From a distance, it would look like a single light flashing.”
“O’Brien, you’re a genius!”
“Well, yes, but the odds are still against them seeing it. And it’s not a very efficient means of communication.”
“All I need is for them to pinpoint our location. Once they do that, I think we can establish two-way radio contact. So how do we get magnesium from sea water?”
The process of getting magnesium from sea water was, as O’Brien promised, fairly simple. It was also time-consuming and labor-intensive. O’Brien estimated that the proportion of magnesium was about one in one thousand, which meant they’d need to process a lot of salt water to get the amount of magnesium they needed. The “signal fire team” consisted of O’Brien, Reyes, Sigurd, Braggi, and a half dozen other men. As far as Reyes knew, none of the Norsemen truly understood the purpose of this endeavor, but by this time they had seen enough of the foreigners’ magic to accept tasks on faith. Most likely they assumed they were building another bomb.
The first problem was finding a source of limestone. Asking around, Sigurd had determined that there was a limestone pit about half a klick to the west. With Sigurd’s help, O’Brien and Reyes built a small wooden cart that could be pulled through the woods by a pair of men. Sigurd tasked Brynjarr and Agnar with transporting powdered limestone to the riverbank. From there, it was loaded into the rowboat and transported downriver to the beach just west of the mouth of the Rouen, where O’Brien and Reyes had decided to set up shop. The site was a three-hour trip from their fort by boat, so they would need to camp there for the duration of the project.
The other raw materials—acid, silica and iron—were simpler to acquire.
Acid was the easiest: Sigurd sent a pair of men to a vineyard a few klicks upriver with a small bag full of silver, and they returned three hours later with three large barrels of vinegar. To refine pure silica from sand, they built a simple charcoal-powered clay furnace with a built-in bellows to keep the temperature high.
Iron was in ready supply, but it was mostly in the form of ingots, tools and weapons. What they needed were iron filings, but there weren’t any metalworking operations in the area large enough to provide the volume they required. Finally Reyes hit upon the idea of using an electromagnet to drag the beach, using a prototype copper-and-lead battery she’d already built for her transmitter project. It took a young Norseman named Eirik less than an hour to come up with a handful of tiny metal shavings. Reyes sent him back for more.
The next challenge was finding enough containers in which to process the seawater. While the limestone was being gathered, Sigurd sent several more men out with silver and furs to trade for barrels and buckets. They came up with eighteen barrels and many more buckets. The barrels were cut in half, and then a finger-sized hole was bored in the side of each, a few centimeters from the bottom. A cork stopper was placed in each of these holes. The barrels were stacked on the rowboat along with the buckets, and rowed to the processing site.
Reyes instructed the men to line up the half-barrels along the beach, just above the high tide line, and then fill the buckets with sea water. As the buckets were filled, O’Brien used a wooden cup to scoop limestone from the pile where Sigurd’s men had dumped it, emptying a cup into each of the barrels. Braggi used a wooden pole to stir the limestone into the water, and after a few minutes a salty white precipitate began to form at the bottom of each barrel. After the water had settled, O’Brien pulled out the stoppers, draining most of the water from the barrels. When all that remained in the barrels was a thin layer of precipitate and a few centimeters of water, he plugged the holes with the stoppers and the process started over.
After they had run through this process a few times, the layer of precipitate at the bottom of the barrels had nearly reached the level of the drainage holes. Following O’Brien’s instructions, the men scooped the salty slurry with their hands and deposited it on a piece of wool cloth he had laid out on the sand. When most of the water had drained from the slurry, O’Brien dumped the stuff into a cast iron pot. He added vinegar to the pot and stirred it until the salt dissolved, and then hung the pot from a tripod suspended over a wood fire. When the liquid had boiled off, iron and silica were mixed in, and the mixture was heated in the clay oven to reduce and vaporize the magnesium. The vapor was caught by the copper pipe contraption they had used to refine sulfur. The vapor condensed into liquid and finally hardened into a powder in a clay pot at the other end of the copper still.
“So that’s it?” Reyes asked.
“That’s it,” O’Brien said. “The calcium carbonate pulls the magnesium out of the salt water solution, giving us magnesium hydroxide. Then the acid in the vinegar reacts with the magnesium hydroxide, producing water and magnesium acetate. We boil off the water, and we’re left with magnesium acetate. Further heating drives off the CO2, leaving magnesium oxide. Mixing that with iron and silica reduces and vaporizes the magnesium, which is collected by the still.”
“How pure is it?”
“Pure enough, I would think. Not much but metallic magnesium is going to make it through the still. We can refine the process if the first test batch doesn’t give us the results we want, but I think we’re in the ball park.”
*****
Reyes and O’Brien tested the product for the first time on the second day of their manufacturing operation. The results were more than satisfactory: the magnesium burned steadily and so brightly they had to throw sand on the fire to keep the gawking Norsemen from burning their retinas. O’Brien tweaked the process a bit to get the proportions correct and reduce waste, but the concept was solid.
How much magnesium they needed was the other big question. O’Brien estimated that they could generate about a kilogram of magnesium per hour at their current rate. Further testing indicated that as little as ten grams of their mixture would create a flash that was visible from three klicks away, even in full sunlight—not that they intended to try to signal Andrea Luhman during the day. Their best chance to be spotted would be on a cloudless night.
Reyes still hoped to establish one-way radio contact with Andrea Luhman prior to sending any signals. Any radio transmission from Andrea Luhman would indicate that she was in range and within line-of-sight. If for whatever reason they didn’t receive any transmissions by the time Andrea Luhman was supposed to be in orbit, they would start sending signals every night. They deemed that a series of quick flashes would be more likely to be noticed than a single, longer burn. Reyes wanted to err well on the safe side in terms of brightness, so she suggested using a hundred grams of magnesium for each flash—ten times as much as they had used in their tests. After some discussion, they settled on five flashes, with a delay of three seconds between each flash. That way, if someone noticed the first flash, they’d have a chance to establish that it was definitely a signal that repeated with regular frequency. If no one saw the signal by the fifth flash, they probably weren’t looking.
Ideally they’d repeat the series at regular intervals, perhaps an hour apart. They were at a fairly high latitude and the nights had been getting shorter, leaving them with about nine hours of darkness. If they sent the first signal just after twilight, that was ten signals a night. Ten signals a night, with five flashes per signal, and a hundred grams per flash, meant they would be using five kilograms of magnesium a day. They’d produced that much in their first day of operation, and Andrea Luhman wouldn’t even be in range for another week.
Reyes kept the operation going for three more days, running from sunup to sundown, with a total output of nearly forty kilograms. They kept the product in buckets, making sure to dampen it occasionally to reduce the risk of accidental fires.
In the evening of the third day, they packed up their supplies and ferried everyone back to the fort.
While they were gone, Gabe and Sigurd had completed the watchtower, with the assistance of several of the Norsemen. Others had begun working on additional buildings, including a storage shed, a latrine and a central building that would serve as a barracks and meeting hall. Another group had begun clearing more land in between the fort and the river, with an eye toward planting crops and raising animals. Wood that was suitable for building purposes was brought inside the fort, while the rest was chopped into firewood. Saplings were made into spear shafts, arrows, or handles for tools. Some of the higher quality hardwood was set aside for building furniture over the winter.
Since Andrea Luhman was still not in range, Reyes occupied herself by setting up an antenna on the watchtower and testing its ability to receive signals over long distance. She decreased the transmission power of O’Brien’s comm by ninety percent and then sent him eight klicks downriver. With her own comm connected to the watchtower’s antenna with copper wire, she was able to receive transmissions from him with minimal static. If Andrea Luhman broadcast a signal from anywhere in orbit on this side of the planet, she’d have no trouble picking it up.
Unfortunately, she didn’t know exactly when Andrea Luhman would return, and she couldn’t spend all day wired to the watchtower. The only copper wire she had was a two-meter-long piece that had probably been intended for a jeweler. It was just long enough to allow her to stand directly below the antenna. She didn’t want to think what might happen if she tried to listen to the radio during a thunderstorm.
As the six week deadline approached, Reyes spent more and more time in the watchtower, hoping to hear from someone on board Andrea Luhman. It turned out, though, that the antenna had been overkill. One night while lying in her tent she was awakened by the sound of Michael Carpenter’s voice in her ear.
“—of the IDL exploratory ship Andrea Luhman,” Carpenter was saying. “I’m trying to reach the crew of the lander. If you guys are down there somewhere, let me know.”
The Dream of the Iron Dragon: An Alternate History Viking Epic (Saga of the Iron Dragon Book 1) Page 36
