4th century BC

• . By the first century potion in the fourth century B.C. for treatment of wounds, gout, and sleeplessness, and as a love Theophrastus) was described by atropin (containing Mandragora4th century BC - anaesthetic[1] for treatment of pain or sleeplessness, to be given prior to surgery or cautery.A.D. Dioscorides recognized wine of mandrake as an 

3rd century BC

• 323–283 BC – Euclid: wrote a series of 13 books on geometry called The Elements

• 287-212 BC - Archimedes of Syracuse: derived an accurate approximation of pi, defined and investigating the spiral bearing his name, and creating a system using exponentiation for expressing very large numbers.

• 280 BC - Aristarchus of Samos: used a heliocentric, heliostatic model

2nd century BC

• 150s BC – Seleucus of Seleucia: discovery of tides being caused by the moon

1st century

• 50 - Pliny the Elder wrote the Natural History

2nd century

• 150s Ptolemy: produced the geocentric model of the solar system.

3rd century

• 200s Galen: produced big contributions to medicine.

9th century

• Al-Kindi (Alkindus): refutation of the theory of the transmutation of metals

10th century

• Muhammad ibn Zakariya al-Razi (Rhazes): refutation of Aristotelian classical elements and Galenic humorism; and discovery of measles and smallpox, and kerosene and distilled petroleum

• 984 - Ibn Sahl accurately describes the optics which became known as Snell's law of refraction

11th century

• 1021 – Ibn al-Haytham's Book of Optics. First use of controlled experiments and reproducibility of its results 

• 1020s – Avicenna's The Canon of Medicine

• 1054 – Various early astronomers observe supernova (modern designation SN 1054), later correlated to the Crab Nebula.

• Shen Kuo: Discovers the concepts of true north and magnetic declination. In addition, he develops the first theory of Geomorphology.

12th century

• 1121 – Al-Khazini: variation of gravitation and gravitational potential energy at a distance; the decrease of air density with altitude

• Ibn Bajjah (Avempace): discovery of reaction (precursor to Newton's third law of motion)

•  (Hibat Allah Abu'l-Barakat al-BaghdaadiNathanel): relationship between force and acceleration (a vague foreshadowing of a fundamental law of classical mechanics and a precursor to Newton's second law of motion)

• Averroes: relationship between force, work and kinetic energy

13th centur

• : Robert Grosseteste1220–1235 – rudimentals of the scientific method (see also: Roger Bacon)

• 1242 – Ibn al-Nafis: pulmonary circulation and circulatory system

• Theodoric of Freiberg: correct explanation of rainbow phenomenon

• William of Saint-Cloud: pioneering use of camera obscura to view solar eclipses[2]

14th century

• Before 1327 – William of Ockham: Occam's Razor

• Oxford Calculators: the mean speed theorem

• Jean Buridan: theory of impetus

• Nicole Oresme: discovery of the curvature of light through atmospheric refraction[3]

15th century

• 1494 - Luca Pacioli: first codification of the double-entry bookkeeping system, which slowly developed in previous centuries[4]

16th century

• 1543 – Nicolaus Copernicus: heliocentric model

• 1543 – Vesalius: pioneering research into human anatomy

• 1552 – Michael Servetus: early research in Europe into pulmonary circulati

• 1570s – Tycho Brahe: detailed astronomical observations

• 1600 – William Gilbert: Earth's magnetic field

17th century

• 1608 - Invention of the telescope

• 1609 – Johannes Kepler: first two laws of planetary motion

• 1610 – Galileo Galilei: Sidereus Nuncius: telescopic observations

• 1614 – John Napier: use of logarithms for calculation[5]

• 1619 - Johannes Kepler: third law of planetary motion

• 1628 – Willebrord Snellius: the law of refraction also known as Snell's law

• 1628 – William Harvey: Blood circulation

• 1638 - Galileo Galilei: laws of falling body

• 1643 – Evangelista Torricelli invents the mercury barometer

• 1662 – Robert Boyle: Boyle's law of ideal gas

•  first Philosophical Transactions of the Royal Society1665 – peer reviewed scientific journal published.

• 1665 - Robert Hooke: discovers the cell

• 1668 – Francesco Redi: disproved idea of spontaneous generation

• 1669 – Nicholas Steno: Proposes that fossils are organic remains embedded in layers of sediment, basis of stratigraphy

• 1669 – Jan Swammerdam: epigenesis in insects

• 1672 – Sir Isaac Newton: discovers that white light is a spectrum of a mixture of distinct coloured rays

• 1673 - Christiaan Huygens: first study of oscillating system and design of pendulum clocks

• 1675 – Leibniz, Newton: infinitesimal calculus

• 1675 – Anton van Leeuwenhoek: observes microorganisms by microscope

• 1676 – Ole Rømer: first measurement of the speed of light

• 1687 – Sir Isaac Newton: classical mathematical description of the fundamental force of universal gravitation and the three physical laws of motion

18th century

• 1745 – Ewald Jürgen Georg von Kleist first capacitor, the Leyden jar

• 1750 – Joseph Black: describes latent heat

• 1751 – Benjamin Franklin: Lightning is electrical

• 1755 - Immanuel Kant: Gaseous Hypothesis in Universal Natural History and Theory of Heaven

• 1761 – Mikhail Lomonosov: discovery of the atmosphere of Venus

• 1763 – Thomas Bayes: publishes the first version of Bayes' theorem, paving the way for Bayesian probability

• 1771 – Charles Messier: Publishes catalogue of astronomical objects (Messier Objects) now known to include galaxies, star clusters, and nebulae.

• 1778 – Antoine Lavoisier (and Joseph Priestley): discovery of oxygen leading to end of Phlogiston theory

• 1781 – William Herschel announces discovery of Uranus, expanding the known boundaries of the solar system for the first time in modern history

• 1785 – William Withering: publishes the first definitive account of the use of foxglove (digitalis) for treating dropsy

• 1787 – Jacques Charles: Charles's law of ideal gas

• 1789 – Antoine Lavoisier: law of conservation of mass, basis for chemistry, and the beginning of modern chemistry

• 1796 – Georges Cuvier: Establishes extinction as a fact

• 1796 – Edward Jenner: small pox historical accounting

• 1796 – Hanaoka Seishū: develops general anaesthesia

• 1800 – Alessandro Volta: discovers electrochemical series and invents the battery

19th century

• 1802 – Jean-Baptiste Lamarck: teleological evolution

• 1805 – John Dalton: Atomic Theory in (Chemistry)

• 1820 – Hans Christian Ørsted discovers that a current passed through a wire will deflect the needle of a compass, establishing a deep relationship between electricity and magnetism (electromagnetism).

• 1821 – Thomas Johann Seebeck is the first to observe a property of semiconductors.

• 1824 – Carnot: described the Carnot cycle, the idealized heat engine

• 1827 – Georg Ohm: Ohm's law (Electricity)

• 1827 – Amedeo Avogadro: Avogadro's law (Gas law)

• 1828 – Friedrich Wöhler synthesized urea, destroying vitalism

• 1830 - Nikolai Lobachevsky created Non-Euclidean geometry

• 1831 – Michael Faraday discovers electromagnetic induction

• 1833 – Anselme Payen isolates first enzyme, diastase

• 1838 – Matthias Schleiden: all plants are made of cells

• 1838 – Friedrich Bessel: first successful measure of stellar parallax (to star 61 Cygni)

• 1842 – Christian Doppler: Doppler effect

• 1843 – James Prescott Joule: Law of Conservation of energy (First law of thermodynamics), also 1847 – Helmholtz, Conservation of energy

• 1846 – Johann Gottfried Galle and Heinrich Louis d'Arrest: discovery of Neptune

• 1848 – Lord Kelvin: absolute zero

• 1858 – Rudolf Virchow: cells can only arise from pre-existing cells

• 1859 – Charles Darwin and Alfred Wallace: Theory of evolution by natural selection

• 1861 - Louis Pasteur: Germ theory

• 1861 - John Tyndall: Experiments in Radiant Energy that reinforced the Greenhouse Effect

• 1864 – James Clerk Maxwell: Theory of electromagnetism

• 1865 – Gregor Mendel: Mendel's laws of inheritance, basis for genetics

• 1865 – Rudolf Clausius: Definition of Entropy

• 1869 – Dmitri Mendeleev: Periodic table

• 1871 – Lord Rayleigh: Diffuse sky radiation (Rayleigh scattering) explains why sky appears blue

• 1873 – Johannes Diderik van der Waals: was one of the first to postulate an intermolecular force: the van der Waals force.

• 1873 – Frederick Guthrie discovers thermionic emission.

• 1873 - Willoughby Smith discovers photoconductivity.

• 1875 – William Crookes invented the Crookes tube and studied cathode rays

• 1876 – Josiah Willard Gibbs founded chemical thermodynamics, the phase rule

• 1877 – Ludwig Boltzmann: Statistical definition of entropy

• 1880 – Pierre Curie and Jacques Curie: Piezoelectricity

• : discovered the laws of chemical dynamics and osmotic pressure in solutions (in his work "Etudes de Jacobus Henricus van 't Hoff1884 – dynamique chimique").

• 1887 – Albert A. Michelson and Edward W. Morley: lack of evidence for the aether

• 1888 – Friedrich Reinitzer discovers liquid crystals.

• 1892 – Dmitri Ivanovsky discovers for the first time a virus

• 1895 – Wilhelm Conrad Röntgen discovers x-rays

• 1896 – Henri Becquerel discovers radioactivity

• 1896 - Svante Arrhenius derives the basic principles of the greenhouse effect.

• 1897 – J.J. Thomson discovers the electron in cathode rays

• 1898 – Martinus Beijerinck: concluded a virus infectious—replicating in the host—and thus not a mere toxin and gave it the name 'virus

• 1898 – J.J. Thomson proposed the Plum pudding model of an atom