C143 The Moment of Boiling

"You'll know if you continue practicing!" Song Hetong smiled mysteriously, and took out a few pieces of black raw materials, throwing them into the crucible. Under Tang Ao's rising flames, they were quickly burnt red.

"Whew, whew, whew!"

Inside the thatched cottage, Tang Ao was sitting on the ground of a blast furnace that was as tall as a person