No law of nature, however general, has been established all at once; its recognition has always been preceded by many presentiments.

Periodic table

In 1863 there were 56 known elements with a new element being discovered at a rate of approximately one per year. g. We must expect the discovery of many yet unknown elements–for example two elements analogous to aluminium and silicon whose atomic weights would be between 65 and 75.

27 January 1834 – 20 January 1907) was a Russian chemist and inventor. Dmitri Ivanovich Mendeleev (Russian: Дми́трий Ива́нович Менделе́ев; IPA: [ˈdmʲitrʲɪj ɪˈvanəvʲɪt͡ɕ mʲɪndʲɪˈlʲejɪf] ([Image] listen); 8 February 1834 – 2 February 1907 O. He created the first version of the periodic table of elements and used it to predict the properties of elements yet to be discovered.