The doodle on the Google home pages in many countries around the world shows Russian chemist Dmitri Mendeleev in the act of setting down the logic of his periodic table (which reportedly came to him in a dream).
Mendeleev had devised the periodic table - the comprehensive system for classifying the chemical elements.
Dmitri Mendeleev was born on February 8, 1834 in the far west of Russia's Siberia. He was the youngest of the many children of his parents.
According to Google's description of the doodle, in 1869, Dmitri Mendeleev made sense of the 56 elements known at the time, showing how they related to each other in a distinct pattern. His periodic table let elements fall into "periods" according to atomic mass and valence (the power that determines how they combine).
Scholars had attempted to organize the elements into a table before, but Mendeleev's work extended beyond mere chart-making. Mendeleev used the logic of his table to argue for the existence of yet-to-be discovered elements (like gallium and germanium), and even to predict their behaviours.
Some of these predictions were wrong, but the basic principles behind his periodic organisation continue to stand at the foundation of modern chemistry.
The periodic table of the elements (now with 118 elements and counting) adorns science classrooms worldwide.
Mendeleev died on February 2m 1907, aged 72, at Saint Petersburg, Russia.
The Dmitri Mendeleev Google doodle has been created by Google doodler Robinson Wood.