White material taken from the damp walls of caverns. When combined with sulfuric acid, saltpeter produces nitric acid by distillation. In addition, saltpeter is one of the.

• 从山洞潮湿的墙壁上获得的白色物质。使用蒸馏的方法,硝石和硫酸作用可产生硝酸。另外,硝石也是制造黑色火药的原料之一。