Chapter 378: The Saltpeter Experimental Workshop
Since mineable saltpeter deposits were currently non-existent and a chemical industry was still a far-off dream, Egger could only rely on the forces of nature to provide the nitrates he needed. He had long heard of the so-called earthen method of saltpeter production, but unfortunately—as a technology unrelated to his profession or interests and long since rendered obsolete—he had never learned the detailed process.
Fortunately, he understood the general principle.
The fluffy snowflakes that precipitate in the corners of latrines, pigpens, and stables are natural saltpeter, resulting from the decomposition and nitrification of organic matter by bacteria. Selecting and focusing this process within reaction pits was the conceptual source of the earthen method.
Understanding the theory was one thing, but Egger lacked the time and energy to personally conduct the experiments needed to derive a method suitable for the world of Ice and Fire from scratch.
Trying to skip basic knowledge and expect people who had no concept of chemical elements or microorganisms to understand terms like nitrates, ammonifying bacteria, or nitrifying bacteria was a pipe dream. However, a driver doesn't necessarily need to know how to build an engine. Egger could bypass the underlying theory and use the personnel of the Research Institute as his hands, directing them to perform the repetitive and tedious work of trial and error through vertical command.
In the instructional outline he personally drafted, Egger compared saltpeter production to brewing wine—brewing requires yeast and grain, while saltpeter production... the bacteria contained in the soil dug from those snowflake corners served as the saltpeter yeast, and dung or urine played the role of the grain. Next, they simply needed to find the production scheme and reaction environment best suited for the Industrial Park through comparative experiments to achieve large-scale production.
What Qyburn was doing in this semi-open-air workshop was exactly that: searching for the optimal process and environment.
"This is Area One, where the project began. Different saltpeter beds here are fed different raw materials: various livestock and human waste, compared against each other." Unable to endure the stench of the testing ground, Melisandre had decided early on to return to Blackwall Keep to rest. Qyburn led the tour group inside, introducing the surroundings with practiced ease. "This comparison is nearing its end. We can conclude that both human and animal waste can be used with similar results. Given the stability and ease of acquisition, we lean toward using human waste."
As Qyburn finished, Nina added timely explanation: "If there's one thing King's Landing has plenty of, it's people. We've already established latrines within the Industrial Park and used a series of rewards and punishments to get employees into the habit of using them. As for the city itself, we've begun communicating with Hand Davos. We don't need much; if we can get permission to build latrines in Flea Bottom and the commoner districts, and have the City Watch guide residents to use them, the raw material will be more than sufficient."
"Very good," Egger nodded. While he spoke words of praise, a faint worry flickered in his mind: Daenerys was occupying Dragonstone and pressing King's Landing, and the capital was under martial law. Adding the chaos of building latrines at such a juncture... and asking the City Watch to stop guarding the walls to teach residents how to use them? It sounded like he had lost his mind.
This was an obvious problem that everyone could see, but no one raised it for fear of dampening morale. Qyburn led the group further: "This is Area Two, where we test the suitable environment required for the 'saltpeter yeast' to act on the waste. After a period of comparison, we have reached several conclusions. First, production is more efficient under non-open-air conditions. Second, unlike brewing wine, the fermentation cannot be in a sealed environment; there must be ventilation. This isn't difficult, but the issue is that ventilation conflicts with heat preservation. We've determined that a temperature that feels 'comfortable for a human' happens to be the temperature where the yeast functions best. However, winter has arrived and temperatures are near freezing. To maintain the right temperature, we need a closed environment, which contradicts the need for ventilation. We are currently trying to find a balance between the two."
Having accounted for basically all the factors he had mentioned, Egger nodded. There was no helping the temperature; Winter was here. Currently, the only place in Westeros with a natural temperature suitable for saltpeter production was likely the southern coast of Dorne, but that was far too remote to consider.
"You could consider establishing a greenhouse at the ventilation intake, preheating the incoming air manually and controlling the fan speed. This would maintain the thermal environment while providing fresh air. But—'a temperature that feels comfortable'? That's too vague. Can't we master and control the temperature more precisely?"
No one answered, including the Associate Dean. They had no idea what Egger was talking about. To Qyburn, a temperature that feels comfortable was already a remarkably precise and rigorous description for this era. Ordinary people used words like cold, hot, or lukewarm. In Westeros, even a natural phenomenon like Winter was only officially recognized when the Citadel sent out white ravens.
After several seconds, Qyburn asked cautiously, "Then, pray tell, my Lord, how should we master the temperature more precisely?"
The world didn't have thermometers yet! Egger slapped his forehead. He hadn't needed to know the exact temperature in daily life, and the scorching heat of the metal smelting in Queenscrown couldn't be measured by simple thermal expansion. He only realized the omission today.
"Have the glassware workshop try to make some thin tubes connected to a hollow bulb at one end, filled with colored liquid. Don't use water—it will freeze. By utilizing the principle that air expands and contracts with heat, causing the liquid level in the tube to rise and fall, you can measure temperature quite accurately," Egger said casually. "Mark a scale on it, using the freezing and boiling points of water as the two extreme standards, and you can calibrate thermometers of different sizes... Hang them in the workshop, and you can achieve the goal of mastering the precise temperature for production."
He said it easily enough, but few around him understood. They looked at each other with blank expressions. For people who didn't even know about thermal expansion and contraction, trying to accept the design concept of a thermometer all at once was a tall order.
But Qyburn understood.
So it could be done that way!
The astonishment in the heart of this expelled former Maester was beyond what ordinary people could fathom. He was the only one of the Deans who had never met Egger in person. He had always felt uncomfortable with the brainless atmosphere of the Institute, where everyone treated the legendary Chief Logistics Officer and current Lord Commander as a semi-divine figure. But at this moment, he suddenly understood why his colleagues mythologized the man in black before him.
If Egger's instructional outline comparing saltpeter production to brewing had only given Qyburn a slight respect for his boss's wisdom, today's conversation made him realize the rumors were true. What shocked him most wasn't that Egger could solve a problem and propose a new invention in the blink of an eye, but the casual, matter-of-fact tone he used. What did that mean? It meant that thermal expansion and the measuring equipment designed from it were not flashes of temporary inspiration, but were already part of his existing knowledge system, brought out the moment they were needed.
What depth of erudition and understanding of nature did that require?
Was this... the advanced knowledge from that mysterious land across the Sunset Sea? Qyburn felt an itch in his heart, wishing he could drag Egger back to a room, tie him up, and interrogate every scrap of knowledge from his mind to solve the mountain of questions he had accumulated over the years.
Of course, that was just a fantasy. The status gap was clear, and Qyburn had found professional dignity and a sense of achievement within the Research Institute—things money couldn't buy. If he wanted to keep his position, he wouldn't actually do anything reckless.
Egger had no idea his casual remarks had stirred such a storm. He was used to pointing things out and making the technology tree grow an inch. The Night's Watch Industry was his own venture; he had no reason to be secretive. It was this very attitude that gave him a lofty reputation among the technical staff—many in this circle were simply waiting for the next golden idea to fall from his lips.
Seeing everyone's confusion, he shrugged. "Never mind. I'll draw a diagram for you when I get back. Let's skip this topic. Next area?"
He was the boss; if he said next area, it was next area. The group pushed their doubts to the back of their minds and swarmed toward the final section.
"Once the saltpeter beds have finished fermenting, we reach the final step," Qyburn suppressed his excitement and led the group forward. "We are testing how long it takes to convert all raw materials. Our current conclusion is about a month, which should be further shortened. The fermented soil is collected and boiled in a pot of water. After letting it sit, the top layer of liquid is removed and filtered several times. Following your suggestion, we add wood ash to the clear liquid and let it settle. In the end, the water contains mostly the saltpeter we want and useless salt," the Associate Dean narrated calmly. "But if we evaporate it directly, there is too much useless salt in the product. We are currently looking for a way to extract the saltpeter separately or remove the impurities."
"Different substances have different solubilities in water, and the solubility of a single substance changes drastically at different temperatures. Utilizing this point might provide a solution." Egger had returned most of his chemistry knowledge to his teachers long ago, but universal points like this were impossible to forget. "On this point, you can consult with the assistants of the Alchemists' Guild still in King's Landing. They often have to dissolve this or extract that when making wildfire; they might be able to help."
What Egger proposed was merely a common recrystallization operation in the modern world. The pyromancers of this world had actually mastered some of its essence, but such operations were internal secrets of the Alchemists' Guild. Only Egger could explain the principle so concisely. To Qyburn, this was another unheard-of harvest... He silently noted the concept of "solubility," feeling a sense of sudden enlightenment.
"Why is there no one here?" Egger noticed a flaw. In this final processing area, pots and pans were piled together, but a place that should have been bustling was deserted. "Has the saltpeter started producing yet? How much stock does the park have?"
"This is the experimental zone," Nina quickly explained. "But in your last letter, you instructed that the arrival of the White Walkers was imminent and the Gift urgently needed saltpeter. You told us to prioritize collecting ready-made saltpeter, and that continuous production could be delayed for a bit."
Egger had indeed written such a letter. "Hmm... but 'delaying it' didn't mean you should stop."
"It hasn't stopped, but the process isn't perfected yet. Each improvement takes at least ten days to show results; we can't have a large crew of workers waiting here. The personnel for boiling saltpeter are all in another workshop not far from here, working day and night."
"Another workshop? You haven't even perfected the fermentation step, where do you get so much saltpeter to boil that you need a separate site for day and night shifts?"
Nina pointed at Qyburn. "That brings us to an accidental discovery by the Institute. My Lord, you told us in the outline that soil dug from the corners of walls where saltpeter grows could serve as 'saltpeter yeast'... But while Associate Dean Qyburn was bored waiting for fermentation results, he tried a small experiment and discovered—there's no need for the complex process of adding waste and waiting for fermentation. The soil dug from those corners can have saltpeter extracted from it directly."
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