Ammonium Carbonate: Sublimed from Sulphate and Chalk (Lunge, 1887)

Commercial ammonium carbonate (sal volatile) as made in the 1880s: ammonium sulphate heated with ground chalk in cast-iron retorts, the ammonia, carbon dioxide and steam condensing as a crust in lead chambers; the crude salt is then resublimed at 70 °C under lead caps into white fibrous cakes 2 in thick. Water vapour must be present, and a little water in the resubliming pots makes the salt transparent. Source: G. Lunge, Coal-Tar and Ammonia, 2nd ed. (1887), pp. 696-699. Picture: the book's text.