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450
Empedocles
Empedocles asserts that all things are composed of four primal elements: earth, air, fire, and water, whereby two active and opposing forces, love and hate, or affinity and antipathy, act upon these elements, combining and separating them into infinitely varied forms. -
Jan 2, 1167
Magister Salernus
Magister Salernus of the School of Salerno makes the first references to the distillation of wine -
Nov 1, 1267
Roger Bacon
Roger Bacon publishes Opus Maius, which among other things, proposes an early form of the scientific method, and contains results of his experiments with gunpowder -
Georg Brandt
Swedish chemist Georg Brandt analyzes a dark blue pigment found in copper ore. Brandt demonstrated that the pigment contained a new element, later named cobalt -
Jacques Charles
Jacques Charles proposes Charles's law, a corollary of Boyle's law, describes relationship between temperature and volume of a gas -
Alessandro Volta
Alessandro Volta devises the first chemical battery, thereby founding the discipline of electrochemistry -
Joseph Louis Gay-Lussac
Joseph Louis Gay-Lussac collects and discovers several chemical and physical properties of air and of other gases, including experimental proofs of Boyle's and Charles's laws, and of relationships between density and composition of gases -
Lord Kelvin
Lord Kelvin establishes concept of absolute zero, the temperature at which all molecular motion ceases -
Gustav Kirchhoff and Robert Bunsen
Gustav Kirchhoff and Robert Bunsen lay the foundations of spectroscopy as a means of chemical analysis, which lead them to the discovery of caesium and rubidium. Other workers soon used the same technique to discover indium, thallium, and helium -
Stanislao Cannizzaro
Stanislao Cannizzaro, resurrecting Avogadro's ideas regarding diatomic molecules, compiles a table of atomic weights and presents it at the 1860 Karlsruhe Congress, ending decades of conflicting atomic weights and molecular formulas, and leading to Mendeleev's discovery of the periodic law -
John Newlands
John Newlands proposes the law of octaves, a precursor to the periodic law -
Adolf von Baeyer
Adolf von Baeyer begins work on indigo dye, a milestone in modern industrial organic chemistry which revolutionizes the dye industry -
Dmitri Mendeleev
Dmitri Mendeleev publishes the first modern periodic table, with the 66 known elements organized by atomic weights. The strength of his table was its ability to accurately predict the properties of as-yet unknown elements -
Hermann Emil Fischer
Hermann Emil Fischer proposes structure of purine, a key structure in many biomolecules, which he later synthesized in 1898. Also begins work on the chemistry of glucose and related sugars -
J. J. Thomson
J. J. Thomson discovers the electron using the cathode ray tube -
Albert Einstein
Albert Einstein explains Brownian motion in a way that definitively proves atomic theory -
Niels Bohr
introduces concepts of quantum mechanics to atomic structure by proposing what is now known as the Bohr model of the atom, where electrons exist only in strictly defined orbitals -
Gilbert N. Lewis
Gilbert N. Lewis develops the electron pair theory of acid/base reactions -
Fritz London and Walter Heitler
Fritz London and Walter Heitler apply quantum mechanics to explain covalent bonding in the hydrogen molecule,[108] which marked the birth of quantum chemistry -
James D. Watson and Francis Crick
James D. Watson and Francis Crick propose the structure of DNA, opening the door to the field of molecular biology