20 August 21

Today's periodic table tie celebrates the work of John Newlands in 1863-1864. "On February 7, 1863, English chemist John Newlands published one of the first table of elements, which divided the known 56 elements into 11 groups based on the “Law of Octaves.” This suggested that any one element will have similar properties to elements eight places before and behind it on the table." (National Day Calendar). Newlands published more about this on 20 August 1864. (OUPblog) About four years later, Dmitri Mendeleev independently produced what became the modern periodic table.