Database of Periodic Tables

Harkins and Hall’s 1919 spiral periodic table With literally hundreds of examples, Dr. Mark R Leach’s “Chemogenesis Web Book” on the history of the display of the periodic table.  Lots of different categories and definitely weird permutations.  Selections here from “Spiral Formulations” section. Monroe and Turner (1926) Janet’s Helocoidal Classification (1926) Via: Make blog