In 1839, Matthias Jakob Schleiden began the development of cell theory, understanding the cellular mechanisms of life.

Freidrich Bessel measures the distance to a star, 61 Cigni, ten light-years away. Bessel used a sixteen-centimeter heliometer made by Joseph Praunhofer in Königsberg.

In 1836, Michael Faraday showed a metal cage shields against electromagnetic radiation.

In 1835, describing the pseudo-forces pertaining to water wheels, Gustave Coriolis described the effect that later was given his name.

In 1834, Michael Faraday observed that electrolysis, like other chemical processes, is not 100% efficient.

In 1834, Michael Faraday observed that particles separated during electrolysis were positively or negatively charged, and called them ions.

In 1834, Jean Charles Athanase Peltier created the first solid-state heating and cooling.

In 1834, Michael Faraday published the laws of electrolysis, describing what happens when electricity breaks molecular bonds to separate elements.

In 1834, Edouard and Louis Lartet discovered bones of Cro-Magnon humans, buried purposefully with stone tools, perforated shells, and animal teeth, among scattered bones of extinct animals.

In 1833, Samuel Hunter Christie invented the Wheatstone bridge to measure an unknown resistance.

In 1833, William Whewell coined the term “scientist.”

In 1831, Michael Faraday investigated Chladni figures and discovered the related phenomenon, standing waves.

In 1831, Michael Faraday invented the electric generator based on the principle of induction.

In 1831, Michael Faraday discovered the law of electromagnetic induction.

In 1830, Charles Lyell established uniformitarianism in geology, which replaced catastrophism and assumes that effects observable today operating over long periods of time are enough to explain the ge...

Thorium: atomic number: 90; weight: 232.0377; Radioactive actinide; discovery: 1829—Morten Thrane Esmark, Jöns Jacob Berzelius

In 1829, Nicolai Lobachevsky, János Bolyai, and Bernhard Riemann established non-Euclidean geometry.

In 1828, William Nicol created the first plane polarizing prism by gluing together two pieces of Island spar.

In 1828, Friedrich Wöhler synthesized urea in the lab. This marks the beginning of modern organic chemistry.

In 1827, Georg Ohm discovered Ohm’s law, the relation between voltage, amperage, and resistance in electric circuits.

In 1826, Karl Ernst von Baer discovered that mammals start their lives from eggs. One supposed difference between us and the animals had to be retracted!

In 1825, Michael Faraday isolated benzene from an oily residue of illuminating gas and analyzed its properties.

Bromine: atomic number: 35; weight: 79.904; Halogen; discovery: 1825,1826—Carl Jacob Löwig, Leopold Gmelin, Antoine Jérôme Balard

Aluminum: atomic number: 13; weight: 26.9815385; Post-transition metal; discovery: 1825,1827—Hans Christian Ørsted, Friedrich Wöhler

In 1823, Michael Faraday showed the relationship between gases and liquids.

In 1821, Thomas Johann Seebeck discovered the thermoelectric effect; in 1834, Hans Christian Ørsted explained that the magnetic field was a result of the generated electric current.

In 1821, Humphry Davy described the basic rules of electric conductivity.

By 1820, Hans Christian Ørsted, André-Marie Ampère, and Michael Faraday discovered and developed the principles and use of electromagnetism.

In 1819, Augustin-Jean Fresnel and François Arago teased out the properties of polarized light and explained how light waves vibrate.

In 1818, John Leslie invented a means of measuring the coldness of the night sky.

Selenium: atomic number: 34; weight: 78.971; Polyatomic nonmetal; discovery: 1817—Jöns Jacob Berzelius, Johan Gottlieb Gahn

Cadmium: atomic number: 48; weight: 112.414; Transition metal; discovery: 1817—Karl Hermann, Friedrich Stromeyer, Johann Roloff

Lithium: atomic number: 3; weight: 6.94; Alkali metal; Discovery: 1817,1821—Johan Arfwedson, William Thomas Brande

In 1817, Heinz Christian Pander discovered that animal embryos develop three layers: ectoderm, mesoderm, and endoderm.

In 1817, Henry Kater build the first reversible pendulum and explained how to use it to measure the local force of gravity.

In 1816, Robert Stirling invented a reversible external-combustion heat engine.

In 1816, Francis Ronalds was the first to create a successful electric telegraph.

In 1815, William Prout proposed that all elements were groupings of hydrogen atoms.

In 1815, William Smith showed that that fossils can be used to identify strata, beginning the science of stratigraphy.

1814-1815: Dietrich Nikolaus Winkel invented the metronome, a balanced pendulum to keep musical time.

In 1814, Joseph von Fraunhofer discovered that each element produces different spectral lines.

In 1813, Jöns Jacob Berzelius outlined the modern system for chemical notation.

In 1812, Friedrich Mohs introduced his standard scale for hardness of minerals.

Iodine: atomic number: 53; weight: 126.90447; Halogen; discovery: 1811—Bernard Courtois

In 1811, Amedeo Avogadro related the molar mass of a compound to the mass of a sample.

In 1809, Jean-Baptiste Lamarck proposed the theory that animals evolve according to their need and that they pass their acquired characteristics to their offspring.

Boron: atomic number: 5; weight: 10.81; Metalloid; discovery: 1808—Humphry Davy, Joseph Louis Gay-Lussac, Louis Jacques Thénard

Calcium: atomic number: 20; weight: 40.078; Alkaline earth metal; discovery: 1808—Humphry Davy

Sodium: atomic number: 11; weight: 22.98976928; Alkali metal; discovery: 1807—Humphry Davy

Potassium: atomic number: 19; weight: 39.0983; Alkali metal; discovery: 1807—Humphry Davy