^			
(BC)

YEAR	EVENT

c.400	The first 'atomic' theory was put
	forward by Democritus.
c.250	Archimedes' principle of
	buoyancy was established.

(AD)

YEAR	EVENT

1600	Magnetism was described by
	William Gilbert.
1608	Hans Lippershey invented the
	refracting telescope.
c.1610	The principle of falling bodies
	descending to earth at the same
	speed was established by Galileo.	
1643	The mercury barometer was
	invented by Evangelista
	Torricelli.
1647	The principles of hydraulics were
	put forward by Blaise Pascal.
1656	The pendulum clock was invented
	by Christiaan Huygens.
1663	Boyle's law concerning the
	behaviour of gases was
	established by Robert Boyle.
c.1665	Isaac Newton put forward the
	law of gravity, stating that
	the Earth exerts a constant
	force on falling bodies.
1690	The wave theory of light was
	propounded by Christiaan
	Huygens.
1704	The corpuscular theory of light
	was put forward by Isaac Newton.
1714	The mercury thermometer was
	invented by Gabriel Fahrenheit.
1764	Specific and latent heats were
	described by Joseph Black.
1771	The link between nerve action
	and electricity was discovered
	by Luigi Galvani.
c.1787	Charles's law relating the
	pressure, volume, and
	temperature of a gas was
	established by Jacques Charles.
1795	The metric system was adopted in
	France.
1798	The link between heat and
	friction was discovered by
	Benjamin Rumford.
1799	Alessandro Volta invented the
	Voltaic cell (announced in
	1800).
1801	Interference of light was
	discovered by Thomas Young.
1808	The 'modern' atomic theory was
	propounded by John Dalton
1811	Avogadro's hypothesis relating
	volumes and numbers of
	molecules of gases was
	proposed by Amedeo Avogadro.
1814	Fraunhofer lines in the solar
	spectrum were mapped by Joseph
	von Fraunhofer.
1815	Refraction of light was explained
	by Augustin Fresnel.
1819	The discovery of
	electromagnetism was made by
	Hans Oersted.
1821	The dynamo principle was
	described by Michael Faraday;
	the thermocouple was discovered
	by Thomas Seeback.
1823	The laws of electrodynamics were
	established by André Ampère.
1824	Thermodynamics as a branch of
	physics was proposed by Sadi
	Carnot.
1827	Ohm's law of electrical
	resistance was established by
	Georg Ohm; Brownian movement
	resulting from molecular
	vibrations was observed by Robert
	Brown.
1829	The law of gaseous diffusion was
	established by Thomas Graham.
1831	Electromagnetic induction was
	discovered by Faraday.
1834	Faraday discovered self-
	induction.
1842	The principle of conservation of
	energy was observed by Julius
	Robert Mayer.
c.1847	The mechanical equivalent of
	heat was described by James Joule.
1849	A measurement of speed of light
	was put forward by French
	physicist Hippolyte Fizeau
	(1819-1896).
1851	The rotation of the Earth was
	demonstrated by Léon Foucault.
1858	The mirror galvanometer, an
	instrument for measuring small
	electric currents, was invented
	by William Thomson (Lord Kelvin).
1859	Spectrographic analysis was made
	by Robert Bunsen and Gustav
	Kirchhoff.
1861	Osmosis was discovered.
1873	Light was conceived as
	electromagnetic radiation by
	James Maxwell.
1877	A theory of sound as vibrations
	in an elastic medium was
	propounded by John Rayleigh.
1880	Piezoelectricity was discovered
	by Pierre Curie.
1887	The existence of radio waves was
	predicted by Heinrich Hertz.
1895	X-rays were discovered by
	Whilhelm Röntgen.
1896	The discovery of radioactivity
	was made by Antoine Becquerel.
1897	Joseph Thomson discovered the
	electron.
1899	Ernest Rutherford discovered
	alpha and beta rays.