The article claims: >In view of the table’s age and emerging uniqueness it was important for the teaching chart to be preserved for future generations. // Does it tell us anything we didn't know, doesn't appear to. So what exactly is the value. I'm a hoarder, and I like curios - particularly scientific ones. But, is their really any need or specific benefit in its preservation? There's a related issue, when paintings…
Does it tell us anything we didn't know, doesn't appear to. 1. Have a look at the heading under "Gruppe." It's the formula of the element's oxide. That hasn't shown up on periodic tables for a long time. It implies that determining the oxide formula may have been tricky for students of the time. Today students are taught how to make any formula (not just oxides) given the group number of the component elements. 2. Me…
According to the Periodic Videos video (linked from another comment), the reason those are there is to justify splitting the list of elements into rows in those particular places. The reasoning today is to do with eletron shells (I'm not a chemist but I presume that electron shells are also the root cause of those formulae) but at the time periodic table was created electrons hadn't yet been discovered!