Clue found to uncover mystery of gunpowder invention Chinese archeologists have found a large ancient saltpeter manufacturing base which they believe was used to manufacture gunpowder over 1,000 years ago. A team of archaeologists discovered last month a network of caves at the Laojun Mountain in southwestern China's Sichuan Province. Xu Xiangdong, leader of the expedition and former president of the Beijing Ancient Building Museum, said the caves were used to manufacture saltpeter, one of the major ingredients of gunpowder. In two caves, the remains of workshops and storage pits were discovered, while in another cave the team found four...