January 6:

• 1561 - Birth of Thomas Fincke, Danish mathematician (d. 1656)

• 1655 - Birth of Jakob Bernoulli, Swiss mathematician (d. 1705)

• 1689 - Death of Seth Ward, English mathematician and astronomer (b. 1617)

• 1731 - Death of Étienne François Geoffroy, French chemist (b. 1672)

• 1795 - Birth of Anselme Payen, French chemist (d. 1871)

• 1838 - Samuel Morse first successfully tests the electrical telegraph

• 1884 - Death of Gregor Johann Mendel, Austrian geneticist (b. 1822)

• 1885 - Death of Peter Christen Asbjørnsen, Norwegian writer and scientist (b. 1812)

• 1907 - Birth of David Fleay, Australian naturalist (d. 1993)

• 1918 - Death of Georg Cantor, German mathematician (b. 1845)

• 1920 - Birth of John Maynard Smith, English biologist (d. 2004)

• 1931 - Thomas Edison submits his last patent application

• 1932 - Birth of Stuart A. Rice, American chemist

• 1945 - Death of Vladimir Vernadsky, Russian mineralogist (b. 1863)

• 1980 - The beginning of the first GPS epoch

• 1990 - Death of Pavel Alekseyevich Čerenkov, Russian physicist, Nobel Prize laureate (b. 1904)