Li Yu knew from his expression that he knew coal. She looked at him in surprise.
Chu Qing smiled and said, "Madam Li, the teacher from the Directorate said that this is something called stone carbon. It can be burned as firewood. The Ministry of War uses this to refine iron and copper weapons."
"Stone carbon!" Li Yu muttered and nodded. "This name is appropriate."
Since Great Yong already knew about coal, and she had been here for so many years, why had she never seen anyone burn coal? Then would anyone buy the briquettes she made?
Chu Qing looked curiously at the black briquettes arranged neatly on the ground. "Madam Li, is this honeycomb made of charcoal?"
Li Yu glanced at Chu Qing. "Yes, it's made of charcoal. Shopkeeper Chu, why have I never seen anyone use charcoal among the commoners?"
