An 1885 version of Mendeleev’s table
You never know what might be lurking underneath your lecture theatre. A wallchart of the periodic table was found at St. Andrew’s University in Scotland that dates back to 1885, just 16 years after Mendeleev first proposed it.
The wallchart of Mendeleev's table dated 1885 (Image from St. Andrew's University).
It is thought this is the oldest surviving wallchart of the periodic table. It is interesting for several different reasons. Firstly a whole group is missing as the noble gases had not yet been discovered on Earth at that time. Spectral lines due to helium were observed in the sun in 1868 but it was not until 1895 that helium was isolated by William Ramsey by reacting cleavite, a radioactive ore of uranium, with acid. The table predates the discovery of sub-atomic particles so, like Mendeleev’s original table, the elements are arranged according to the similarities in their chemical properties rather than their atomic number. This explains why the groups are based on the formulas of the oxides and hydrides of the elements and some elements are ‘in the wrong place’ and some, e.g. copper, appear twice. It is also interesting to see where gaps have been left, e.g. germanium (Ar = 72) in group IV, for elements that had still not been discovered by 1885. In fact, germanium was discovered one year later in 1886 by Winkler and the true genius of Mendeleev was that from his table he was able to predict accurately the properties of germanium before its discovery.
I think it is interesting both from an international-mindedness perspective and from a nature of science perspective too. Note the name, “Periodische Gesetzmässigkeit der Elemente nach Mendelejeff”, which translates from the German as “Periodic regularity of the elements according to Mendeleev”. Russian speaking countries still call it the Mendeleev Table. This wallchart from 1885 shows that in the West we used to include Mendeleev in the table’s name too but somehow, maybe during the Cold War (?), the West has dropped Mendeleev’s name. Perhaps in this year 2019, which is the 150th anniversary of the table, Mendeleev’s name should be rightfully restored to ‘his’ table in the West too?