Chapter 172: Earth Cement

“How do you know? Were you eavesdropping?” Yan Lao’er asked nervously.

Yan Yu was speechless. Did he really think she was that kind of person?

Could there at least be a basic level of trust between a father and his daughter?

She tapped her own little head.

“It’s all in here. I just saw Uncle Hu helping to mix a kind of white powder, and it immediately clicked.”

The formula for earth cement, which only required a few ingredients, was really easy to remember.

Of course, just knowing the ingredients wasn’t enough—the key was the ratio.

Yan Yu didn’t know how good Master Lu’s recipe was, but what she did know was the result of countless improvements and refinements made by many people.

It was also the collective choice of numerous online novel authors.

“Master Lu is probably using clay, quicklime, and gypsum.”

She secretly signaled her father to take a look.

Yan Lao’er casually glanced over, pretending not to be interested.

Clay—no doubt about that. It had even been transported back by some of the young men from their village.

The lime was also easy to identify. But as for the gypsum, he couldn’t tell.

“How do you know that’s gypsum?” Yan Lao’er asked curiously.

Yan Yu grinned like a little fox. “I don’t recognize it, but Doctor Cui does. Gypsum is also a medicinal ingredient, so I took a bit over to him and had him confirm it for me.”

Yan Lao’er was impressed.

“That simple? Then why is Master Lu being so secretive about it? If someone paid close enough attention, they could figure it out too.”

Yan Yu replied, “Father, of course, it’s not that simple. The ratio is crucial. And besides, I suspect Master Lu is adding something extra.”

“What kind of extra ingredient?”

Yan Yu thought for a moment. “I’ve read that this kind of earth cement has decent strength, but its frost resistance is poor and it takes a long time to set. To speed up the setting process, adding some mirabilite should do the trick. And for frost resistance, increasing the amount of adhesive should help a lot.”

A sudden inspiration struck her. “Dad, this is Guanzhou, a border city. The best mortar recipe should be the one used for building city walls! I remember that in ancient times, they would boil glutinous rice paste and mix it with sand to create an incredibly strong mortar. Wait, let me think… brown sugar, elm bark, camphor… black camphor tree sap! Hahaha, yes! That’s it!”

Yan Yu felt immensely proud of herself. Just look at this memory of hers! Who else could compare?

If it weren’t for the setting, Yan Lao’er would have lifted his daughter high into the air in celebration.

She was amazing!

Even more impressive than the three treasures!

Then he thought about their failed geothermal heating project.

He asked his daughter, “Dabao, do you think our geothermal heating idea has a chance now?”

Yan Yu gave him a long, exasperated look.

“Father, let’s be realistic. Geothermal heating… that’s not something common folk like us should even be thinking about. You should ask around—even the prince of Guanzhou, Lord Ying, might not have such luxuries.”

She scrunched up her little face and advised earnestly, “What have we done to deserve such things, Father?”

Yan Lao’er: …

“A heated wall is already great, and if we connect it to a heated bed, that would be perfect.”

Yan Yu was already imagining herself rolling around on a heated brick bed, getting toasted on both sides… how delightful!

“Whose formula is better, yours or Master Lu’s?” Yan Lao’er asked.

“Mine, of course,” Yan Yu replied confidently.

“Then what should we do? Should we swap out his mortar for ours?” Naturally, if they had a better formula, they’d want to use it for their own house.

Yan Yu only had to say one thing to change his mind.

“Boiled glutinous rice paste, brown sugar… Father, those aren’t just adhesives. That’s money!”

Yan Lao’er immediately agreed.

And so, the father and daughter happily decided to stick with the original plan.

“But if we leave out those two ingredients, we can still try the rest,” Yan Yu said eagerly, rubbing her hands together, ready to get to work.

“Earth cement has so many uses. If we can recreate it—or at least make enough for our needs—that’ll be enough. Once the house is built, we’ll still need it for courtyard walls, stone flooring inside, and leveling the ground outside with cement.”

“Oh, and the toilet! Dad, let’s stop obsessing over geothermal heating—the toilet is the real priority!”

They had experienced firsthand the importance of proper sanitation as soon as they arrived in this world.

Speaking of the toilet, Yan Yu continued, “And we should build a cement pit for our… ‘homemade fertilizer.’ Dad, the hole you dug is too shallow. We should learn from this and dig it deeper next time.”

Yan Lao’er: …

And she said he was the one fixated on things? At least his ideas didn’t stink. But his daughter? She was focused on the smelliest thing possible.

Yan Yu sighed, knocking herself on the head.

Unfortunately, her memory wasn’t perfect. There were still many things she couldn’t recall clearly.

Like glass-making and brewing alcohol—those were the real money-making techniques for a transmigrator!

—

Yan Lao’er didn’t have time to keep chatting with his daughter. He rushed off to the riverside field.

When he arrived, he couldn’t help but marvel:

Aunt Rong—truly—was worth two men!

Even the weeds were piled up so neatly.

All he had to do now was set them on fire.

Burning weeds had to be done with extreme caution, especially in areas with dense vegetation. A careless mistake could lead to disaster.

Yan Lao’er called over a few of the Song family’s sons-in-law to help.

The Song family had a large number of descendants, but unlike Village Chief Luo’s family, they had many daughters instead.

Old Man Song and his wife were capable people, and they had raised beautiful, hardworking daughters. Their approach to choosing sons-in-law was unique—not requiring them to change their surname or officially marry into the family, but simply allowing them to live with the Song family after marriage.

As long as the groom agreed, they didn’t even ask for a bride price.

This single condition made families from miles around eager to marry into the Song family.

No need to change their surname, no need to pay a bride price, and they still got to enjoy the Song family’s resources—who wouldn’t want that?

As a result, the three daughters brought in three sons-in-law.

Originally, the Song family’s youngest son was a frail only child, but ever since his three brothers-in-law moved in, not only did he become healthier, but the Song family even had another little addition.

The youngest Song child was a year younger than Yan Yu.

What was this? This was wisdom!

Recruiting three sons-in-law was basically like getting three extra sons for free!

Yan Lao’er felt he needed to learn from them.

Expand his horizons.

—

They started with a small fire, slowly adding the weeds one rake at a time.

No rushing.

The flames grew quickly, reaching high into the air.

Today was windless—perfect weather for burning weeds.

The four men carefully controlled the fire to prevent it from spreading.

The weeds weren’t completely dry yet, so thick smoke billowed up.

Yan Lao’er ran a little farther away to catch his breath, then quickly returned.

A mask!

Dear heavens, he really missed masks!

Back when he had to wear one every day, he never appreciated it. But now that he didn’t have one, he deeply regretted it.

The pain of inhaling smoke—only those who had experienced it would understand.

If he had another chance to burn weeds…

He would definitely make a mask first!

—

Back at their homestead, Master Lu was overseeing the screening of the clay.

The fine clay was sifted multiple times, then mixed evenly with quicklime and gypsum in a set ratio.

Water was added. The mixture was stirred.

Then…

Just as Yan Yu predicted, Master Lu poured in two bamboo tubes of liquid.

Yan Lao’er curiously approached and took a sniff.

A sweet scent.

It was brown sugar.

At that moment, Yan Lao’er felt at peace.

Master Lu’s craftsmanship, his construction crew, and the cost of adding brown sugar…

Somehow, it all felt worth it.