Way back in 1771, Swedish chemist Karl Wilhelm Scheele was investigating the properties of a mineral known as fluorspar (calcium fluoride). He mixed the pulverized rock with sulfuric acid and...
The thick liquid used to be called "oil of vitriol," since it was originally made by the distillation of "green vitriol," or iron sulfate as we know it today. It was so corrosive and nasty that...