Chemistry Timeline By MikeJMelly Jan 1, 1700 Death of Alchemy LinkThe disroving of Aristotle's four-elements theory. Period: Jan 1, 1774 to Jan 1, 1794 Disproving of the Phlogiston Theory Link Antoine Lavoisier who disproved the Phlogiston Theory. He renamed the "dephlogisticated air" oxygen when he realized that the oxygen was the part of air that combines with substances as they burn Jan 1, 1800 Datlons Theroy LinkJohn Dalton publishes his Atomic Theory Jan 1, 1854 First Vacuum LinkHeinrich Geissler creates the first vacuum tube. Jan 1, 1885 The Discovery of The Proton LinkEugene Goldstein discovered positive particles Jan 1, 1895 Discovery of X-Rays LinkWilhelm Roentgen accidentally discovered x-rays Jan 1, 1897 Raidoactive elements LinkMarie Curie discovered uranium and thorium within pitchblend Jan 1, 1897 Joseph John Thomson British physicist Joseph Thomson discovered the electron. [Link](<a href='http://dl.clackamas.edu/ch104-04/dalton's.htm)' >Link</a> Jan 1, 1911 Ernest Rutherfords atomic theroy LinkErnest Rutherford publishes his atomic theory describing the atom as having a central positive nucleus surrounded by negative orbiting electrons. Jan 1, 1913 Bohr Atomic LinkIn 1913 Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus.