In 1869, Dmitri Mendeleev discovered how to classify elements into a periodic table. Although other scientists had been trying to find a way to classify the elements, Mendeleev's version was the clearest and most systematic.
The key to Mendeleev's formulation of the periodic table of elements was his realization that if he used atomic weight as the organizing principle, the relationship between the elements made sense. Soon after this realization, he presented his work to the Russian Physico-Chemical Society. Soon after that, the work was published in "Zeitschrift für Chemie," the leading chemistry journal of the day. Through that work, Mendeleev's formulation was spread to other scientists who refined and adopted it.