The INTERNET Database of Periodic Tables
There are hundreds of periodic tables in web space, but there is only one comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Dr Mark R Leach.
Alchemical Emblem Showing the Four Classical Elements
From the German Photo Library Theosophie & Alchemie, a seventeenth century alchemical emblem showing the four classical elements (air, fire, earth & water) in the corners of the image, alongside the tria prima on the central triangle:
© Mark R. Leach 1999-
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