Chapter 378

Currently, there are no exploitable saltpeter mines, and the chemical production systems are still far from being established. In this situation, Aegor could only rely on nature to provide the saltpeter he needed. The traditional method of saltpeter extraction, often referred to as the "primitive method," was something he had heard of before. Unfortunately—being unrelated to his profession or interests and having long been replaced by more advanced techniques—he had no detailed knowledge of its processes.

Fortunately, he understood the basic principles.

The fluffy “snowflakes” that form naturally in toilets, pigsties, and the corners of stables—natural saltpeter—result from bacteria breaking down organic matter and nitrifying it. If this process could be selectively replicated in controlled reaction pits, that would form the foundation of the traditional saltpeter production method.

While the concept was simple enough to grasp, developing an effective method for this world would require time and effort that Aegor could not spare. Explaining concepts like nitrate salts, ammonia-oxidizing bacteria, and nitrifying bacteria to people who had no knowledge of chemical elements or microorganisms would be like speaking gibberish. But just as a driver doesn’t need to know how to build an engine, Aegor could skip over the principles and use direct instructions, having the staff of the industrial research institute act as his "hands" to carry out the repetitive and tedious trial-and-error work.

In the guidelines he personally wrote, Aegor likened saltpeter production to brewing alcohol: yeast and grain were essential for brewing, just as soil containing the bacteria needed for nitrification served as the "yeast" for saltpeter production, while feces and urine acted as the raw "grain." By conducting comparative experiments to determine the most suitable production methods and conditions for the compound’s facilities, they could achieve large-scale saltpeter production in Westeros.

This was precisely what Qyburn had been working on in the semi-open workshop: experimenting to find the optimal conditions for saltpeter production.
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“This is Zone 1, where the project began. In these various saltpeter beds, we’ve introduced different raw materials—human and animal excrement—so we can compare their effects,” Qyburn explained, leading the group through the gates while Melisandre, unable to endure the stench, had already retreated to Blackwall Keep for rest. “The comparative results are nearly conclusive: both human and animal waste are effective, with similar results. Considering the stability and availability of raw materials, we lean toward using human waste.”

Qyburn finished speaking, and Nina promptly supplemented, “King’s Landing, if nothing else, has plenty of people. Toilets were built in the compound early on, and we’ve implemented a system of rewards and penalties to encourage employees to use them. As for the city itself, we’ve started discussions with Hand of the King Davos. We only need permission to construct public toilets in Flea Bottom and the slums, and some cooperation from the City Watch to guide the residents.”

“Good,” Aegor said with a nod, though a hint of worry lingered in his mind. With Daenerys advancing on King’s Landing and martial law in place, constructing toilets and redirecting the City Watch seemed like a risky and poorly-timed endeavor. However, the potential problems were evident to everyone, and none raised them aloud to avoid demoralizing their group.

Qyburn led them forward. “This is Zone 2, where we test the optimal conditions for the bacteria—the ‘nitrate yeast’—to act on the raw materials. Through comparative tests, we’ve drawn several conclusions: first, the process is more efficient under enclosed conditions. Second, unlike brewing alcohol, the fermentation of feces and urine cannot take place in a sealed environment; some ventilation is necessary. This creates a conflict between ventilation and insulation: maintaining optimal temperatures requires a relatively enclosed space, but ventilation disrupts that environment. We’re currently working to strike a balance between the two.”

Aegor nodded in approval. He had anticipated most of these factors. Temperature was indeed a challenge; with winter’s arrival, only the southern coastal regions of Dorne likely offered the natural warmth needed for the process, but that was far too remote to be practical.

“You could consider attaching greenhouses near the ventilation inlets to preheat incoming air while controlling airflow speed. This would maintain the necessary temperature while still providing ventilation. But—‘comfortable temperature’? That’s too vague. Can’t you measure the temperature more precisely?”

His question was met with silence. No one, not even Qyburn, understood what Aegor meant by “precisely.” For most people in Westeros, temperature was described using vague terms like “cold,” “hot,” or “not too cold, not too hot.” Even the arrival of winter was officially recognized only when the Citadel released white ravens to announce it.

After a few seconds, Qyburn cautiously asked, “How might we measure temperature more precisely, my lord?”

Aegor smacked his forehead. Of course—they didn’t have thermometers in this world! It had simply never occurred to him before, as daily life didn’t require precise temperature readings, and the extreme heat of metal smelting couldn’t be measured through simple thermal expansion either.

“Have the glass workshop create thin tubes connected to hollow glass spheres filled with colored liquid—not water, as it would freeze. By using the principle of thermal expansion, the liquid will rise or fall in the tube with changes in temperature. Mark the tube with a scale, using the freezing and boiling points of water as reference points for calibration. With these, you’ll be able to measure the exact temperatures needed for saltpeter production.”

Though Aegor explained it simply, few around him fully grasped the concept. They exchanged bewildered glances, struggling to comprehend the idea. However, Qyburn’s eyes lit up.

“Fascinating!” Qyburn’s astonishment was palpable. As a former maester who had always been skeptical of the reverence others held for Aegor, he suddenly realized why this man was so highly regarded. Aegor’s suggestion wasn’t just practical—it was transformative, revealing a depth of knowledge beyond anything Qyburn had encountered.

For Qyburn, the most remarkable part wasn’t the invention itself but the casual, matter-of-fact manner in which Aegor presented it. This wasn’t a moment of inspiration—it was knowledge Aegor already possessed, pulled effortlessly from his mind as though it were second nature.

Could this be the advanced knowledge of the mysterious lands beyond the Sunset Sea? Qyburn felt an almost overwhelming urge to interrogate Aegor for every scrap of information in his mind, though he quickly suppressed the thought. His position in the research institute had given him a sense of purpose and value he wouldn’t risk losing.

Unaware of the storm of thoughts he had stirred in Qyburn, Aegor shrugged at the confused faces around him. “Forget it. I’ll draw a diagram for you later. Let’s move on to the next area.”
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When they reached the final zone, Qyburn explained the last stage of the process: extracting saltpeter from the fermented materials. “After about a month of fermentation, the nitrate-rich soil is collected and boiled in water. The liquid is then filtered multiple times to remove impurities, followed by the addition of wood ash to precipitate further. What remains is primarily saltpeter and common salt. However, when evaporated, the mixture still contains too much salt, so we’re exploring ways to purify the saltpeter further.”

“Different substances dissolve at different rates in water, and their solubility changes with temperature. Exploiting this could be key,” Aegor suggested. “The Alchemist’s Guild in King’s Landing might have insights. Their work with wildfire often involves dissolving and extracting substances. Seek their advice—they might help.”

Though Aegor’s advice described basic recrystallization, it struck Qyburn like a revelation. He silently noted the concept of solubility, already envisioning ways to apply it.
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Just as Aegor began to feel satisfied, he noticed something odd. The final processing area, where workers should have been boiling and purifying saltpeter, was empty. The tools and containers sat unused. “Why isn’t anyone working here? Do we have any saltpeter stockpiled?”

“This is the experimental zone,” Nina quickly explained. “Your last letter instructed us to prioritize collecting naturally formed saltpeter due to the urgency of the White Walker threat. You also said the production process could wait.”

“That’s true,” Aegor acknowledged. “But ‘wait’ doesn’t mean stop entirely.”

“We haven’t stopped,” Nina clarified. “The process isn’t fully optimized yet. Each adjustment takes weeks to yield results, so we couldn’t justify keeping workers idle here. Instead, the boiling and purification are being carried out at a separate facility, where workers are operating around the clock.”

“How do you have enough saltpeter to keep them busy if the fermentation process isn’t complete?” Aegor asked, puzzled.

Nina gestured toward Qyburn. “That’s where the research institute made an unexpected discovery. Your guidelines instructed us to collect soil from nitrate-rich corners as the ‘starter culture.’ But during his experiments, Vice Dean Qyburn realized that these soils didn’t need to go through the fermentation process at all. They already contained extractable nitrate.”

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