Sulphuric acid works illustrating the Chamber proces, 1890.
© Science Museum / Science & Society Picture Library
Model (scale 1:24). Sulphuric acid (H2SO4) was originally made by heating a substance then known as green vitriol (hydrated iron (II) sulphate), and absorbing the gas given off in water, (hence 'oil of vitriol'). By 1746, Roebuck and Garbett achieved better yields by burning a mixture of brimstone (sulphur) and saltpetre (potasium nitrate) over water in large lead reaction chambers, the basis of the lead chamber proces shown in this photograph.