All Stemma nodes

The full list of graph nodes in chronological order. Every node has its own page with the text, the dating rationale and all its links.

c. 1 million years ago Control of fire
c. 28,000 years ago Firing of clay
c. 20,000 years ago Counting and recording quantity
c. 7000 BCE Fermentation as a reproducible practice: beer, bread, wine
c. 5000 BCE Copper smelting from ore
c. 3300 BCE Tin bronze smelting
c. 3200 BCE Writing
c. 400 BCE "Airs, Waters, Places": disease from air, waters and locality
c. 340 BCE The doctrine of spontaneous generation in Aristotle's "Generation of Animals"
c. 300 BCE The Elements: definition, axiom, proof
2nd c. BCE The loom that stores the pattern in a set of shafts (the Laoguanshan models)
1st c. CE Transparent blown glass
c. 77 CE Mordant dyeing: alum fixes the colour
c. 105 Paper as a cheap writing surface
c. 300 CE Distillation and laboratory apparatus
c. 492 Saltpetre as a substance: Tao Hongjing's flame test
c. 600 The stirrup and the dispute over its social consequences
5th-7th c. Positional decimal system and zero
9th century The Graeco-Arabic translation movement in Baghdad
c. 820 Algebra as a distinct method
c. 850 First record of a saltpetre, sulphur and carbon mixture flaring up
c. 950 The fire lance: gunpowder in a tube
c. 1028-1038 Book of Optics and experiment as argument
1044 The first printed gunpowder formulae (Wujing Zongyao)
c. 1090 Su Song's astronomical clock tower and the water-wheel escapement
12th century Latin translations from Arabic in Toledo and Spain
1150 Papermaking in Europe: Xàtiva and Fabriano
c. 1200 The university as a guild of masters and students (Paris, Bologna)
1202 Liber abaci: Indian numerals and Arabic algebra in a Latin book
c. 1240 Saltpetre reaches the Arabs: "Chinese snow" in Ibn al-Baytar
c. 1267 The dispute over Bacon's gunpowder recipe
c. 1280 Purifying saltpetre with wood ash: Hasan al-Rammah
c. 1286 Ground lens and eyeglasses
c. 1288 The metal barrel: a bronze hand-gun of c. 1288
c. 1280-1300 Gunpowder in a Latin text: the Book of Fires of Marcus Graecus
late 13th c. The weight-driven mechanical clock with verge escapement
c. 1300 Mineral acids of the pseudo-Geber corpus
c. 1290-1311 Tanqih al-manazir: a revision of the Book of Optics and an explanation of the rainbow
1326 The earliest European illustration of a gun
c. 1450-1455 Movable-type printing press
1527 Bastion fortification in Verona
1537 Mathematics enters artillery
1585 Decimal fractions in computation
c. 1600-1630 Obstetric forceps kept secret by a single family for over a century
1604 The retinal image and the theory of lenses (Ad Vitellionem paralipomena)
c. 1605 The grande tire drawloom: the design as a set of cords and the work of the drawboy
1609/1619 The laws of planetary motion
1608 to 1609 Spyglass turned to the sky
1614 Logarithms and tables
1637 Analytic geometry
1638 Parabolic trajectory of a projectile
1644 Torricelli's ballistic tables
1648 Van Helmont's weight balance and the willow experiment (Ortus medicinae)
1665, 1670s Microscope and the discovery of the cell
1665 Scientific journal
1668 Redi: meat in sealed and open flasks (Esperienze intorno alla generazione degl'insetti)
1673 Systematic siege by trenches
1665/1684 Differential and integral calculus
1687 Mathematical Principles of Natural Philosophy
c. 1700 Phlogiston theory (Becher, Stahl)
c. 1706 Prussian blue: the first purely synthetic pigment
1714-1828 The Longitude Act of 1714 and the Board of Longitude
1725 Selecting the cords by a perforated paper roll (Bouchon)
1728 The punched card as a separate row of the design, laced into an endless chain
1731 The double-reflecting octant
1742 The ballistic pendulum and air resistance
1745 (Dublin) The lying-in hospital: childbirth as an observed, repeated and counted event
1745 A figured-weaving loom without a drawboy (Vaucanson)
1745 The German edition of Robins with Euler's mathematics
1747 The wave equation and the vibrating string controversy
1748 The language of analysis: the function as the basic object
1740-1750 Inspector of dyeing: an academy chemist put in charge of colour
1752 Smellie: printed rules for applying the forceps and teaching midwifery on a machine
1752-1770 The lunar tables of Tobias Mayer
c. 1760–1795 Bakewell's livestock breeding: in-and-in mating, culling and letting of sires
1761-1762 The longitude problem and the marine chronometer (John Harrison's H4)
1761–1766 Artificial plant hybridization as a repeatable experiment
1748 / 1765 Needham (1748) and Spallanzani (1765): infusions, boiling and sealed flasks
1767 The Nautical Almanac and the lunar-distance method in the mariner's hands
1772 Weight gain of metals in calcination as a general fact (Guyton de Morveau)
1773 Soil mechanics and the stability of a fortification wall
1774 Mechanized boring of the cannon barrel
1775 The French state gunpowder administration
1777-1786 Oxygen theory of combustion and "Réflexions sur le phlogistique"
1785-1789 Chlorine bleaching: a gas instead of a meadow and the sun
1783-1789 Caloric (calorique) as a weightless conserved fluid
1789 Mass balance and the conservation principle
1794 The Revolution's state engineering school
1795 Gordon: childbed fever is brought to the woman by whoever attends her delivery
1797 Law of definite proportions (Proust)
1798 Rumford: heat from friction in cannon boring
1798 'An Essay on the Principle of Population': population outruns subsistence
1804-1805 The punched-card loom (Jacquard machine)
1805 (1809) The method of least squares
1803-1808 Chemical atomic theory
1809 Inheritance of acquired characters: the second law of the 'Philosophie zoologique'
1814/1817 Dark lines of the solar spectrum
1814–1820 The Sheep Breeders' Society in Brno: heredity becomes a subject in its own right
1810s Berzelius: organic substances are formed by a vital force (Lebenskraft)
1801-1821 Wave optics of Young and Fresnel and the luminiferous ether
1820–1821 Telegony: Lord Morton's mare and the 'infection' of the dam by her first mate
1822 (1807) The analytical theory of heat and Fourier series
1824 "Réflexions sur la puissance motrice du feu" (Carnot)
1828 Wöhler: artificial formation of urea from ammonium cyanate
1829-1832 Non-Euclidean geometry: denial of the fifth postulate
1830 Berzelius introduces the concept of isomerism
1830–1833 'Principles of Geology': the Earth's past explained by causes now in operation and by vast time
1831–1833 Brown: the nucleus as a regular constituent of the living cell
1835 'Sur l'homme': the astronomers' law of error applied to people
1837 Babbage's Analytical Engine: a design that stayed on paper
1836-1838 Brewer's yeast turns out to be a living organism: Cagniard-Latour, Schwann, Kützing
1839 Liebig: fermentation is transmitted decomposition, not the work of a living thing
1838–1839 Schleiden and Schwann: the cell as the common unit of structure and growth in plants and animals
1842 Chadwick: Report on the Sanitary Condition of the Labouring Population of Great Britain
1843 Hamilton's quaternions
1843 Holmes: «The Contagiousness of Puerperal Fever», a compilation of cases against the profession
1843-1850 Mechanical equivalent of heat (Joule)
1847 Disinfection of hands with chlorinated lime in a maternity ward
1850-1851 The two laws of thermodynamics (Clausius 1850, Thomson 1851)
1852–1855 Remak: animal cells arise by division that begins with the nucleus
1854 (publ.1868) Geometry of manifolds and curvature (Riemann)
September 1854 John Snow: cholera is transmitted by water (1849; Broad Street 1854; book 1855)
1855–1858 Virchow: every cell from a cell, and disease as the life of cells under altered conditions
1856 Mauveine: the first synthetic aniline dye from coal tar
1857-1876 Pasteur: fermentation is the physiological work of living cells, from the Bigo factory to the Études sur la bière
1858/1860 Unified system of atomic weights (Cannizzaro, Karlsruhe)
February 1858 Wallace, 'On the Tendency of Varieties to Depart Indefinitely from the Original Type': natural selection found independently
1859 Florence Nightingale as a miasmatist: ventilation, cleanliness, denial of "separate diseases"
1859, 1860 Spectral analysis
1859 Domestic breeds as an argument: artificial selection in the Origin of Species
24 November 1859 'On the Origin of Species': natural selection as the mechanism of species formation
1860-1877 Kinetic theory of gases and statistical mechanics
1859-1862 Pasteur: swan-neck flasks and the memoir on organized corpuscles in the atmosphere
1864/1870 Lothar Meyer's system of the elements
1865 Maxwell's electromagnetic theory of light
1865–1866 'Versuche über Pflanzen-Hybriden': segregation of characters and numerical ratios
1867 Lister: the antiseptic principle in surgery (as an outgrowth of the refutation of spontaneous generation)
1868 Pangenesis: gemmules from the whole body gather in the germ cells
1868-1869 Alizarin from coal-tar anthracene: the madder dye repeated in the laboratory
1869 Periodic law
1869–1871 Blood transfusion in rabbits: no gemmules in the blood
1879–1882 Chromatin and mitosis: longitudinal splitting of the nuclear threads in cell division
1883 Hansen: a yeast culture grown from a single cell at the Carlsberg Laboratory
1883-1884 Koch isolates the cholera pathogen; germ theory displaces miasma
1884-1885 Vector analysis and the vector form of the field equations
1886–1889 Regression to the mean and correlation: heredity as statistics
1887 The Michelson-Morley experiment
1891-1895 Energetics: physics without atoms
1889-1892 The FitzGerald-Lorentz contraction hypothesis
1885–1892 'Das Keimplasma': the continuity of the germ plasm and the mouse-tail experiment
1896–1900 Pearson's correlation coefficient and the chi-square test
1896-1897 Buchner: alcoholic fermentation by cell-free yeast juice, and zymase
1895–1899 Ewart's Penycuik experiments: Lord Morton's case repeated with a zebra
1900 Quantum of action
1900 Three papers of 1900: de Vries, Correns and Tschermak bring back Mendel's laws
1900–1901 The journal Biometrika: the statistics of life gets a journal of its own
1902–1906 The biometric-Mendelian debate: continuous or discontinuous heredity
1902–1904 Boveri's multipolar mitoses: chromosomes are qualitatively different and individual
1902–1903 'The Chromosomes in Heredity': chromosome behaviour as the physical basis of Mendel's laws
1905-1909 Brownian motion as a measurement of molecules
1905 Special theory of relativity ("Zur Elektrodynamik bewegter Körper")
1905–1906 Bateson gives the science of heredity a name: 'genetics'
1903–1909 Johannsen: pure lines, genotype and phenotype
1910–1915 The white-eyed fly: a gene tied to a chromosome, linkage and the first genetic map
1918 The correlation between relatives on the supposition of Mendelian inheritance: biometry and Mendelism reconciled