Ice made from saltpeter, immense production of steel.

At that moment, everyone was captivated by Li Zhi’s demonstration. They gathered around him, curious to see what he would do next.

Li Zhi instructed Liu An to pour the contents of the large cloth bag into two water jars and placed two copper basins inside each. Once these preparations were finished, Li Zhi addressed the crowd, “Ladies and gentlemen, now is the moment to witness a miracle.”

As his words fell, a tranquil silence gave way to a gentle white mist rising from the water jars. Soon, everyone was astonished to feel a chill emanating from the jars, swiftly dispelling the heat from their bodies and cooling the air around them.

Then, to their amazement, the water in the jars began to freeze, and even the milk in the copper basins slowly solidified. The crowd was left speechless, mouths agape and eyes wide, as they waited for the next change.

Li Zhi, small in stature, was carried by Liu An so he could watch closely. Seeing that the milk in the basin had nearly solidified, he quickly asked Baken to place the molds into the copper basin. He then directed Baken to insert bamboo sticks into each partition of the molds.

Now, all that remained was to wait for the milk to completely freeze.

Seizing the moment, Li Zhi explained to Li Shimin, “Father, while developing gunpowder with Liu An, I discovered that saltpeter has the property of absorbing heat.”

Li Shimin asked in surprise, “Are you saying that there is saltpeter in the jars?”

Li Zhi nodded, “Yes, Father. I am using saltpeter’s characteristics to create a refreshing icy drink for you and the esteemed gentlemen.”

Fang Xuanling, nearby, remarked, “Who would have thought that such an ordinary substance as saltpeter could have such a marvelous use? Truly, wonders never cease.”

Changsun Wuji added, “Your research in the study of physical phenomena, Zhinü, has reached unprecedented heights. In just a short time, you have contributed several vital resources to our Great Tang.”

Hearing Changsun Wuji’s words, the others nodded in agreement, their faces full of envy as they looked toward Li Shimin.

Wang Gui was the first to congratulate Li Shimin, “To have such a gifted son is your fortune, and indeed the fortune of our Great Tang.”

The others followed suit, “Congratulations, Your Majesty! Felicitations!”

Li Shimin laughed heartily, “Please, do not praise him too much, lest Zhinü become conceited.”

Pei Feishu replied with a smile, “Your Majesty need not worry. His Highness, the Prince of Jin, is always approachable and has never shown any arrogance.”

Yan Lide chimed in, “My mentor’s talent and character are exemplary. It is my great fortune to be his student.”

Li Shimin, delighted by the repeated praise for Li Zhi, could hardly contain his joy. Laughing and waving his hand, he replied, “You flatter him too much, too much.”

Cradled in Liu An’s arms, Li Zhi felt his skin prickling from the compliments. He glanced at the ice pops, now fully formed, and said, “Father, Uncle, esteemed gentlemen, the icy treats are ready to be enjoyed.”

At his words, everyone quickly turned their attention to the copper basins. Li Zhi guided Baken to distribute the ice pops one by one.

Seeing the guests unsure of how to eat them, Li Zhi took the lead, licking and then biting into his own ice pop. The others immediately followed his example and tried theirs.

A chorus of delighted sighs swept through the group. The cool sensation, combined with the rich fragrance of milk, seemed to open every pore. The occasional breeze whisked away the sweat lingering on their bodies. In that moment, they forgot the summer heat entirely, feeling utterly refreshed.

The cold air from the water jars further cooled the surroundings, soothing their impatience as they waited.

Before long, faint cheers could be heard from the iron-smelting workshop. Soon, an excited craftsman ran out, shouting, “We’ve done it! We’ve succeeded!”

Li Shimin rushed forward to meet him, grabbing his arm, “Is it true? Have you really succeeded?”

The craftsman, too thrilled to remember protocol, exclaimed, “Yes, we’ve truly succeeded!”

Li Shimin immediately hurried into the workshop, followed by the others. Upon entering, their eyes sought out the blast furnace.

Baken had already climbed to the observation port, carefully inspecting the process. Moments later, he called out to Li Shimin, “The molten iron is ready, Your Majesty! Please give the order to open the furnace.”

With a sweeping gesture, Li Shimin declared, “Open the furnace!”

At his command, two men lifted a long iron hook and opened the outlet. Glowing molten iron, trailing flames, slowly flowed from the blast furnace.

The iron followed a pre-laid channel, guided steadily into molds. Li Shimin watched anxiously, awaiting the last drop to emerge, so he could confirm the final yield—whether it was truly ten times more, as Li Zhi had promised.

The answer soon arrived. Once the molten iron had run dry, a worker quickly reported a figure: thirty thousand jin.

The number stunned everyone, and several gasps echoed through the hall.

Li Shimin, hardly able to believe it, turned to the others, seeing their faces mirrored his own shock.

With a trembling voice, he asked again, “Are you certain it’s thirty… thousand jin?”

The worker replied enthusiastically, “Yes, Your Majesty! Thirty thousand jin, truly thirty thousand jin!”

Hearing this confirmation, Dai Zhou, the Minister of Revenue, murmured, “Profit! We’ve profited!”

Everyone knew this investment had paid off—and not just paid off, but paid off handsomely.

As the highest officials of Great Tang, they knew precisely the empire’s annual steel output. That knowledge was what made the result so astonishing.

Previously, the entire empire’s yearly steel production was about two million jin. Now, just this single blast furnace had yielded thirty thousand jin in one batch.

Most astonishing of all, the process took only three hours—less than half the time it used to take.

Now, the way they looked at Li Zhi was completely transformed. Where they once regarded him with admiration and awe, now their gaze was filled with genuine respect.

They began to overlook his youth, seeing him as a capable minister worthy of standing shoulder to shoulder with them.