Pan Yun said, "I believe you, but metallurgy has seen no obvious progress for years, and you are not even anxious."
Hu Cheng muttered, "A person's energy is limited. I have devoted all my effort to researching cannons."
Pan Yun said, "Then you have not researched it thoroughly enough. Do cannons not need steel or iron? How can you improve cannons without improving the materials? And if you want to improve the materials, how can you avoid improving the methods of smelting them?"
Hu Cheng had nothing to say.
Pan Yun spread out the blueprints. The iron mines they had discovered and mined so far were only a tiny fraction of those in later generations; many more iron deposits remained undiscovered and unmined.
Hu Cheng leaned closer. "National Preceptor, are we going after iron mines next?"
Pan Yun nodded.
Hu Cheng asked, "For the sake of building that railway?"
"Steel and iron have countless uses. Besides, if I am building railways, how could I build only one?"
Hu Cheng swallowed and looked at Chen Feng. "Eunuch Chen, did you not say last time that you wanted to modify the iron-smelting furnace?"
"Yes." Chen Feng stepped forward and said, "To turn iron into steel, temperature is paramount. Raising the temperature and speeding up the heating process can increase both iron-smelting and steelmaking yields. I discovered that regenerators can be added to the furnace."
Pan Yun's eyes lit up, and she immediately turned to face him. "Have you made progress?"
Chen Feng's face reddened slightly. He said softly, "The existing furnaces are all in use, and iron production cannot be delayed, so a new furnace would have to be built separately. It might not succeed, either, and would require considerable expense. The ministers impeached this official for wasting public funds, so..."
Pan