There are many exceptions to this rule, however, including iron being put in the same group as sulfur and oxygen - explaining why it was disregarded by other scientists (jan 1, 1864 – 23h 59min, dec 31, 1864 y)
Added to timeline:
Date:
jan 1, 1864
23h 59min, dec 31, 1864 y
~ 12 months