C197 Method of Making Ice

Xiaoyu smiled. "Of course! Daddy, do you remember the saltpeter I mentioned to you before? "

Zhang Daniu thought about it and nodded. "Remember, what does it matter?"

"Of course it does! This saltpeter had another name, it was called Wall Frost! It's a good thing to make ice! "

"What?" Ice! Is it the kind of ice that the winter water turned into? " Zhao Qun shouted in surprise