1. The role of change is a theme in the writer's “The Role of Past, Current, and Future Technologies in Chemical Engineering,”;Chem. Eng. Prog.,1987
2. The Chemical Industry During the Nineteenth Century;Haber,1958
3. Particularly interesting sources are George Lunge's authoritative articles on “Alkali Manufacture” and “Sulfuric Acid”,1910
4. About Ernest Solvay, see the article on him,1961
5. On Norman Swindin, “The George E. Davis Memorial Lecture,”;George Davis;Trans. Inst. Chem. Eng.,1953