apr 10, 1864 - Dimitri Mendeleev saw in a dream a table where all elements fell into place as required. Awakening, he immediately wrote it down on a piece of paper, only in one place did a correction later seem necessary. By adding additional elements following this pattern, Mendeleev developed his extended version of the periodic table.
Added to timeline:
Date:
apr 10, 1864
Now
~ 161 years ago