Nitric Acid (Aquafortis) from Saltpetre and Oil of Vitriol, Ure 1839

Nitric acid, the old aquafortis, has been distilled from saltpetre since the 13th century. Andrew Ure (1839) gives the small-scale way: saltpetre and strong sulfuric acid heated in a glass retort, the acid vapour condensed in a cooled receiver. The strong acid is then let down with water to 68 %, the strength sold today.