100 Best Books for an Education

A Revision and Update of Will Durant's 100 Best Books for an Education

Note 15

 

Milestones in Science

 

 

YEAR

DISCOVERY

WHO OR WHERE/WHAT IT IS

50,000 B.C.E.

Counting

Counting was probably one of the earliest forms of speech, and in many tribes it still presents a relieving simplicity. Perhaps it began during the Upper Paleolithic period.

35,000

Tally stick/

Lunar calendar

Scholars believe the Lebombo bone found in Swaziland to be a tally stick; it has 29 separate intentionally cut notches in a baboon’s fibula. Present-day Namibian Bushmen use similar calendar sticks.

10th millennium

Trephining

 

 

Eurasia; trephining of the skull was practiced by primitive medicine-men from the ancient Peruvian Indians to the modern Melanesians; the latter averaged nine successes out of every ten operations, while in 1786 the same operation was invariably fatal at the Hôtel-Dieu in Paris.

4223

Beginnings of the modern calendar

The Egyptians establish the “modern” calendar on a day that Sirius heliacally rose.

4000

Opium

Near East

3500

Astronomic periods

 

 

The Mesopotamians determine the solar year, the lunar month, and the seven-day week. The division of our month into four weeks, of our clock into twelve hours (instead of twenty-four), of our hour into sixty minutes, and of our minute into sixty seconds, are unsuspected Mesopotamian vestiges in our contemporary world.

3000

Ayurveda

 

 

 

 

 

 

 

 

Miasma theory of disease

This “the science of longevity” is the oldest system of Hindu medicine. In it illness is attributed to a disorder in one of the four humors (air, water, phlegm, and blood), and treatment is recommended with herbs and charms. The Rig-Veda names over a thousand such herbs and advocates water as the best cure for most diseases. Even in Vedic times physicians and surgeons were being differentiated from magic doctors, and were living in houses surrounded by gardens in which they cultivated medicinal plants. It may have influenced later physicians such as Hippocrates and Galen.

 

At first people around the globe think that disease is a punishment from the gods, but it is probably the Hindus who first consider it as something brought on by foul vapors/air i.e. miasma.

2700

Acupuncture

The ancient Chinese use this method of controlling the body’s flow of energy to heal. By the 17th century, it reaches the West.

2000

Planetary movement

 

 

Sex in plants

Mesopotamian observations reveal that there are “stars” that move in the sky and follow patterns, demonstrating that the Earth is part of a solar system of planets separate from the fixed stars.

 

Mesopotamia

1900

Law of “Pythagoras”

a2 + b2 = c2

Thirteen hundred years before Pythagoras’ birth, the Mesopotamians understood this quite well.

 

1800

Geometry problems

 

Quadratic equation

Egyptian Moscow mathematical papyrus

 

 

In Berlin Papyrus 6619, Egyptian mathematicians deal with a quadratic equation and provide its solution.

17th century

Venus tablet

 

Mesopotamian astronomers of Ammisaduqa’s time make the first known observations on Venus.

1650

Fractions, first degree algebraic equations

In the Rhind mathematical papyrus the Egyptians displayed their knowledge of fractions, but always with the numerator 1; to express ¾ they wrote ½ + ¼. The Arabs of the Islamic Golden Age added a horizontal bar between numerator and denominator to give us our modern form of the fraction. The Rhind illustrates by examples the computation of the capacity of a barn or the area of a field, and passes to algebraic equations of the first degree.

1600

Basic empirical methodology in medicine

The Edwin Smith papyrus, an Egyptian medical textbook, employs the procedure of examination, diagnosis, treatment, and prognosis, to the curing of disease—precisely the procedure we use today.

1500

Cosmological theory

“The Hindu Rigveda of ancient India,” writes Luke Mastin “describes the origin of the universe in which a ‘cosmic egg’ or Brahmanda, containing the Sun, Moon, planets and the whole universe, expands out of a single concentrated point before subsequently collapsing again, reminiscent of the much later Big Bang and oscillating universe theories.”

1500-1200

Infinity

The Hindu Yajurveda makes the earliest extant reference to it

1150

Navigation using the pole star

Phoenicians

1000

Magnetism

The ancient Greeks learn about the magnetic properties of the lodestone and its ability to attract iron.

9th century

Heliocentric theory

 

 

 

Yajnavalkya, a Hindu philosopher, speculates that the Sun lay at “the center of the spheres” of the universe. Contemporaneously, his fellow countryman Mahidasa Aitareya also proclaims this doctrine in his Brahmana. As late as the 3rd century B.C.E., Aristarchus of Samos also proposes a Sun-centered universe.

800-600

Geometry, quadratic equations, the square root of two, the Pythagorean theorem and Pythagorean triplets 

The Hindu Shulba Sutra

7th century

Magic square

Mathematical table discovered in China and brought west in the 14th century via Islam.

6th century

Communicable diseases

 

 

 

 Geometric theorems

 

 

Electricity, static

 

Row cultivation of crops/

Intensive hoeing

The Old Testament, like most ancient peoples, recognized that some diseases were communicable and isolated individuals thought to carry “infections.” This included the shunning of lepers, which occurs even today.

 

Thales of Miletus, born of Phoenician parents, pursued the fascinatingly logical study of geometry as a deductive science, and demonstrated several of the theorems later collected by Euclid.

 

Thales of Miletus

 

 

China

 

 

5th century

Geobotanical prospecting

China

495

Formal geometry

Death of Pythagoras in whose academy geometry now definitely received the form of axiom, theorem, and demonstration.

460

Atomic theory

Leucippus and his student Democritus conceive the theory that everything is composed of tiny indivisible atoms; in 1808, John Dalton proposes that a different atom with a different weight comprises each element.

4th century

Precursor of Newton’s first law of motion

 

Recognition of sunspots as solar phenomenon

China; this is found in the Mo jing, a Mohist philosophical compilation of Mozi’s thought. Alhazen also independently formulated this concept in the 11th century.

 

The Chinese first make this discovery which then comes to European notice in the 15th century via Islam.

360

Planetary models

Eudoxus of Cnidus

355

Advances in geometry

Death of Eudoxus of Cnidus whose contributions to geometry were fundamental. He invented the theory of proportion, and most of the propositions, transmitted to us in the fifth book of Euclid; and he devised the method of exhaustion, which made it possible to calculate the area of the circle and the volume of the sphere, the pyramid, and the cone; without this preliminary work, Archimedes would have been impossible.

350

Earth’s rotation

 

The ideal of science and formalized logic

Heraclides of Pontus

 

Aristotle’s Posterior Analytics defends the process of science as one that moves from unquestioned axioms to demonstrable proof. He also sets down the rules for correct reasoning in his Organon.

343

Disease prevention

Aristotle teaches Alexander the Great to boil drinking water and bury feces to prevent disease.

3rd century

Ephedrine

 

Euclidean geometry

 

Conics

 

 

 

 

 

 

Method of finding prime numbers

 

Archimedes’ early form of integration

China

 

Euclid of Alexandria

 

Apollonius of Perga, after years of study in Euclid’s school, took Euclid’s Conics as the starting point of his own Conics, and explored in eight “books” and 387 propositions the properties of the curves generated by the intersection of a cone by a plane. To three of these curves (the fourth being the circle) he gave their lasting names—parabola, ellipse, and hyperbola. His discoveries made possible the theory of projectiles, and substantially advanced mechanics, navigation, and astronomy.

 

Eratosthenes of Cyrene

 

We must rank Archimedes of Syracuse (287-212 B.C.E.) with Isaac Newton, and credit him with “a sum of mathematical achievement unsurpassed by any one man in the world’s history” according to Sir Thomas Heath.

270

Force of compressed air

Ctesibius of Alexandria

250

Archimedes’ principle

 

Size of the Earth

 

 

Heart valves

Archimedes of Syracuse

 

 

Eratosthenes of Alexandria calculates the size of the earth and its distance from the sun and the moon.

 

Erasistratus of Ceos

2nd century

Science of endocrinology

China

150

Lunar causation of tides

 

Founding of trigonometry

Seleucus of Seleucia

 

 

His mathematical studies of astronomic relations led Hipparchus of Nicaea to formulate a table of sines, and thereby to create the science of trigonometry.

85 C.E.

Scientific method

Chinese thinker Wang Chong publishes his Lunheng (“Disquisitions”) in which he as a rationalist “insisted upon the necessity of supporting any theory with concrete evidence and experimental proof,” so says the Encylopedia Britannica.

2nd century

Negative numbers

 

“Gaussian” elimination

 

“Horner’s” method

 

 

 

 

Decimal fractions

China

 

China

 

 First discovered in China, this appears in Nine Chapters on the Mathematical Art, a Chinese textbook, which receives its final form at about this time. In the Nine Chapters, positive quantities are shown as red rods and negative ones as black rods. Additionally, “Gaussian” elimination also finds its first expression in this text.

 

China

150

Geocentric cosmology

Ptolemy of Alexandria did not claim to do more than systematize the work and observation of previous astronomers Hipparchus above all. Ptolemy pictured the universe as spherical and as daily revolving around a spherical, motionless earth. He suggested further a theory of eccentrics to explain the orbits of the planets, and discovered the evection, or orbital aberration, of the moon.

3rd century

Biological pest control

 

Algebra treatise

 

 

 

 

 

 

 

 

 

Mensuration, arithmetic, fractions, simple, cubic, and quartic equations, permutations and combinations, geometry, and number theory

China

 

Diophantus of Alexandria composes Arithmetica, his chief surviving work, which is a treatise on algebra. It solves determinate equations of the first degree, determinate quadratic equations, and indeterminate equations up to the sixth degree. For the unknown quantity which we denote by x, and which he called arithmos (the number)—he used a Greek sigma; and for the other powers he used the letters of the Greek alphabet.

   Algebra owes its name to the Arabs, who extensively developed this detective science. The great figure here was al-Khwarizmi for the word algebra (al-jabr—“restitution,” or “completion”) entered the West from the title of one of his books; another of his books introduced a great deal of Muslim trigonometry.

 

From the Sthananga Sutra, a Jain text from India

Late 4th century

Mathematical commentaries

 

The most interesting figure in the science of this age is that of the pagan mathematician and philosopher Hypatia. Her father Theon is the last man whose name is recorded as a professor at the Alexandrian Museum; he wrote a commentary on Ptolemy’s Syntaxis, and acknowledged the share of his daughter in its composition. Hypatia, says Suidas, wrote commentaries on Diophantus, on the Astronomical Canon of Ptolemy, and on the Conics of Apollonius of Perga. None of these works survives.

499

Mathematics textbook

The greatest of Hindu astronomers and mathematicians, Aryabhata, discussed in verse such poetic subjects as quadratic equations, sines, and the value of π. He explained eclipses, solstices and equinoxes, announced the sphericity of the earth and its diurnal revolution on its axis, and wrote, in daring anticipation of Renaissance science: “The sphere of the stars is stationary, and the earth, by its revolution, produces the daily rising and setting of planets and stars.”

6th century

Discovery of the solar wind

China

550

Inoculation

Unknown to Europe before the eighteenth century, it is known in India by this date if we may judge from a text attributed to Dhanwantari, one of the earliest Hindu physicians. “Take the fluid of the pock on the udder of the cow . . . upon the point of a lancet, and lance with it the arms between the shoulders and elbows until the blood appears; then, mixing the fluid with the blood, the fever of the smallpox will be produced.”

    To prevent smallpox the Chinese, probably in imitation of India, begin to practice inoculation around the 10th century; they use weakened virus from a smallpox-infected human being. This practice spreads westwards. Lady Mary Wortley Montagu had found inoculation customary in Constantinople in 1717; on her return to England in 1724, she recommended the procedure. It was tried upon criminals, then upon orphans, with considerable success.

575

Astronomy treatise

Varahamihira authors the Pancha-siddhantika (“Five Treatises”), a compendium of Egyptian, Greek, Roman, and Indian astronomy that frankly acknowledged his dependence upon the Greeks. In it, he notes the shifting of the equinox as 50.32 seconds.

7th century

The use of chopped thyroid gland for the treatment of goiter

China

628

Gravity as a force of attraction

Brahmagupta states, “[b]odies fall towards the earth as it is in the nature of the earth to attract bodies, just as it is in the nature of water to flow.”

9th century

Magnetic declination

 

Alchemy becomes chemistry

 

 

 

 

 

 

 

 

 

Refutation of the trans-mutation of the elements

 

 

Heavenly bodies subject to earthly physical law

 

 

 

 

Earth

measurements

 

 

 

 

 

Refutation of the Aristotelian classical elements and Galenic humors

China

 

 

“Distillation, the means of separating liquids through differences in their boiling points,” writes Paul Vallely “was discovered in prehistoric times but perfected around the year 800 by Islam’s foremost scientist, Jabir ibn Hayyan, who transformed alchemy into chemistry, inventing many of the basic processes and apparatus still in use today—liquefaction, crystallization, distillation, purification, oxidization, evaporation and filtration. As well as discovering sulphuric and nitric acid, he invented the alembic still, giving the world . . . perfumes and alcoholic spirits (although drinking them is haram, or forbidden, in Islam). Ibn Hayyan emphasized systematic experimentation and was the founder of modern chemistry.”

 

Al-Kindi also develops frequency analysis, which initiates the study of cryptology.

 

 

Jafar Muhammad ibn Musa (one of the Banu Musa brothers) posits the existence of gravitation between heavenly bodies; this is a precursor to what became Newton’s law of Universal Gravitation.

 

 

The Caliph al-Ma’mun engaged a staff of astronomers to make observations and records. Taking for granted the sphericity of the earth, they measured a terrestrial degree by simultaneously taking the position of the sun from both Palmyra and the plain of Sinjar; their measurement gave 91.2 kilometers—0.8 kilometers more than our present calculation; and from their results they estimated the earth’s circumference to be a little over 32,000 kilometers.

 

 

 

Rhazes also differentiates measles from smallpox, and distills kerosene from petroleum.

 

10th century

Modern surgical instruments

 

 

 

 

 

 

 

 

 

Advancement of algebra

“Many modern surgical instruments,” writes Paul Vallely “are of exactly the same design as those devised in the 10th century by a Muslim surgeon called al-Zahrawi [Abulcasis]. His scalpels, bone saws, forceps, fine scissors for eye surgery, and many of the 200 instruments he devised are recognizable to a modern surgeon. He discovered that catgut used for internal stitches dissolves away naturally (a discovery he made when his monkey ate his lute strings) and that it can be used to make medicine capsules. . . .” Muslim doctors also invented anesthesia by inhalation, which they practiced in some surgical operations; in others, hashish and other drugs were used to induce deep sleep.

 

Abu Kamil Shuja ibn Aslam

 

929

Advancement of trigonometry

Death of Abu Abdallah al-Battani, a Sabaean of Raqqa known to Europe as Albategnus, who advanced trigonometry far beyond its beginnings in Hipparchus and Ptolemy by substituting triangular for Ptolemy’s quadrilateral solutions, and the sine for Hipparchus’ chord; he formulated the trigonometrical ratios essentially as we use them today.

964

Andromeda Galaxy

Abdel-Rahman al-Sufi

984

“Snell’s” law

Ibn Sahl discovers the law of refraction later incorrectly termed Snell’s law.

11th century

Binary system

 

 

 

 

 

Astronomy/

physics advances

“The Chinese book I Ching . . .” writes Roger Bridgman “showed how to make predictions from binary patterns. The 11th century Chinese philosopher Shao Yung was influenced by the book, and it is possible that German mathematician Gottfried Leibniz was made aware of the binary system through his writings.”

 

Abu Rayhan Muhammad al-Biruni notes “the attraction of all things towards the center of the earth,” and proves that gravitation also works on heavenly bodies/celestial spheres. He also disparages Aristotle’s opinion that circular motion is their inherent property.

1011-21

Use of mathematics to explain the principles of light

Besides discovering a precursor to Newton’s first law of motion, we know al-Haitham (Alhazen) chiefly by his Kitab al-Manazir, or Book of Optics; of all medieval productions, this is probably the most thoroughly scientific in its method and thought. AI-Haitham studied the refraction of light through transparent mediums like air and water, and came so close to discovering the magnifying lens that Roger Bacon, Witelo, and other Europeans three centuries later based upon his work their own advances toward the microscope and the telescope. He rejected the theory of Euclid and Ptolemy that vision results from a ray leaving the eye and reaching the object; rather “the form of the perceived object passes into the eye, and is transmitted there by the transparent body”—the lens. He remarked on the effect of the atmosphere in increasing the apparent size of sun or moon when near the horizon; showed that through atmospheric refraction the light of the sun reaches us even when the sun is as much as nineteen degrees below the horizon; and on this basis he calculated the height of the atmosphere at about forty kilometers. He analyzed the correlation between the weight and the density of the atmosphere, and the effect of atmospheric density upon the weight of objects. He studied with complex mathematical formulas the action of light on spherical or parabolic mirrors, and through the burning glass. He observed the half-moon shape of the sun’s image, during eclipses, on the wall opposite a small hole made in the window shutters; this is the first known mention of the camera obscura (from the Arabic word qamara or dark chamber), on which all photography depends. We could hardly exaggerate the influence of al-Haitham on European science. Without him, we might never have heard of Roger Bacon; Bacon quotes him or refers to him at almost every step in that part of the Opus maius that deals with optics; and Part VI rests almost entirely on the findings of the Cairene physicist. As late as Kepler and Leonardo European studies of light were based upon al-Haitham’s work.

    Continued research by Sir Isaac Newton (1704), Thomas Young (early nineteenth century), and Albert Einstein (1905) leads to a more specific knowledge of light’s nature, behavior, and mode of transmission.

1020

Experimental medicine

Avicenna discovers the contagious character of infectious diseases including pulmonary tuberculosis, the sexually transmitted diseases amongst others, and that water and soil frequently transmit them. He likewise discovers the difference between mediastinitis and pleurisy, and writes a medical text that includes mention of various parasitic worms.

12th century

Three-field system

 

Precursor of Newton’s second law of motion

 

Precursor of Newton’s third law of motion

Europe

 

Abu’l-Barakat al-Baghdadi

 

 

 

Ibn Bajjah (Avempace)

1121

Gravitation/

Air density

Al-Khazini makes breakthroughs in gravitation, discovers that its potential energy varies with the distance from the center of the Earth, and that air density decreases with increasing elevation.

1185

Differential calculus

Death of Bhaskara II who crudely anticipated this branch of calculus

1260

Pulmonary circulation of the blood

A physician of Damascus, Ala’al-din ibn-al-Nafis, expounded the pulmonary circulation of the blood 270 years (1260?) before Servetus. Almost three hundred years later William Harvey experimentally proved how the heart circulates blood around the body.

1269

Magnetic poles

Petrus Peregrinus de Maricourt

14th century

Multivariate polynomials/Solutions to simultaneous polynomial equations

 

Ockham’s “Razor”

Chinese mathematicians discover this but it is not till the 17th century that it reaches the West.

 

 

William of Ockham determines that the theory with the fewest assumptions provides the simplest explanation and is the one closest to the truth.

1543

Human anatomy textbook

 

 

 

 

 

Heliocentric theory, Revived

Andreas Vesalius dissects human corpses, uncovers exhaustive data regarding human anatomy, and amends Galen’s views. Vesalius thinks that the comprehension of anatomy is vital to successfully carrying out surgery and therefore dissects human corpses himself (a rarity for that time). He publishes De Humani Corporis Fabrica and revolutionizes anatomy.

 

Nicolaus Copernicus places the sun, not the Earth, at the center of the solar system.

1545

Complex numbers

Gerolamo Cardano creates “complex numbers” which are numbers such as 3 + 9i, or a real number plus an imaginary number.

1546

Theory of contagion

Girolamo Fracastoro develops the concept that minute bodies (“germs”) capable of self-replication, transmitted from infector to infected, cause infectious disease. He is said to have named syphilis.

1570

Detailed planetary observations

Tycho Brahe compiles the data, which leads Kepler to formulate his famous laws.

1572

Supernova

Tycho Brahe

1582

Calendar, Gregorian

Aloysius Lilius and Christopher Clavius

1600

Earth’s magnetic field/study of electricity

William Gilbert

1603

“Valves” in veins

Girolamo Fabrizio

1604

Law of falling bodies

Galileo Galilei upends the Aristotelian conviction that heavy things fall faster than light things by demonstrating that all bodies fall with the same acceleration.

1605–09

Planetary orbits are elliptical

Johannes Kepler

1614

Logarithms

John Napier

1633

Slide rule

William Oughtred

1637

X-Y coordinate graph

René Descartes

1661

Blood capillaries

Marcello Malpighi

1662

Boyle’s law

Robert Boyle discovers the this the first in a series leading to the Ideal Gas Law.

1663

Electrostatic investigations

Otto von Guericke

1665

Number theory, analytic geometry, and calculus

Death of Pierre de Fermat who worked on all these areas

1665-66

Fundamental Theorem of Calculus

The power to find a function once we know the derivative allows us to calculate quantities that change over time. Sir Isaac Newton discovered this mathematical method for determining the total pull applied by the Earth on the moon; however, he was reluctant to publish. The investigation of motion in space also inspired German philosopher Gottfried W. Leibniz to work out his calculus, and he published it between 1684 and 1686. Leibniz also popularized the symbols currently in use.

1666

Laws of Motion

Sir Isaac Newton discovers three laws of motion that change our understanding of the universe. The second law leads him to develop a mathematical formula for gravitation.*

1674

Microorganisms

Anton van Leeuwenhoek, a microscope lens maker, inadvertently discovers microorganisms in a drop of water. With his own microscopes, he views sperm, bacteria, and blood cells. His examinations lay the groundwork for the science of microbiology.

1676

Measurement of the speed of light

Olaus Roemer

1690

Wave theory of light

Christiaan Huygens

1727

Euler’s Number e ≈ 2.71828. . . .

The irrational number e serves as the base of natural logarithms. It appears quite frequently in calculus wherever one is working with either logarithmic or exponential functions, because the natural logarithm function is the inverse of the exponential function. It occurs in some mathematical problems: those concerning non-linear growth or decay (e.g. compound interest), the statistical “bell curve,” certain areas of probability, various counting problems, in Stirling’s Formula which approximates factorials (!), and even in the analysis of the distribution of prime numbers. Additionally there is a link between e and complex numbers via Euler’s Equation. Mathematicians calculate it by adding: 1/0! + 1/1! + 1/2! + 1/3! + 1/4! . . . ≈ 2.71828. . . .

1735

Classification of species

Carl Linnaeus, the “father of taxonomy,” advances a method for the nomenclature and classification of every form of life. It is still in use (though modified).

1738

Bernoulli’s principle

Daniel Bernoulli

1752

Nature of electricity

Benjamin Franklin

1766

Hydrogen

Henry Cavendish

1774

Oxygen

Both Carl Scheele and Joseph Priestley discover oxygen. Antoine Lavoisier names the new element oxygen and correctly explains its role in combustion.

1785

The Milky Way is a gigantic disk of stars

Astronomer William Herschel, aided by his sister Carolyn, maps the whole sky and demonstrates that the Milky Way is an enormous disk of stars that protrudes at its center and that our solar system exists within it.

1792

Metric system

In 1791 the French Revolutionary government appointed a commission, headed by Joseph-Louis Lagrange, to devise, for a newly unified France, a new system of weights and measures; the resultant metric system was officially adopted in 1792, and was made law in 1799; it had to fight its way through the provinces, and its victory was not complete till 1840. Now the world uses it.

1796

Vaccination

In England in 1760, Drs. Robert and Daniel Sutton reported that in thirty thousand cases of smallpox inoculation they had had twelve hundred fatalities. Could there be found a surer method of preventing smallpox? Edward Jenner was led to a better way by noting that many milkmaids in his native Gloucestershire contract cowpox from the infected nipples of cows, and that these women are thereafter immune to smallpox. It occurs to him that a like immunity might be established by inoculating with a vaccine (vacca is Latin for cow) made from the virus of a pox-infected cow.

1799

Stratigraphy

William Smith

1801

Ultraviolet light

Johann Ritter

1806

Morphine

F. W. A. Sertürner

1811

Atoms combine to form molecules

Amedeo Avogadro discovers that the atoms of elements combine to produce molecules. Additionally, he states that equal volumes of gases under equal conditions of temperature and pressure hold an equal number of molecules (6.02214 x 1023) now known as Avogadro’s number.

1813

Math analysis, number theory, algebra, and differential calculus

Death of Joseph-Louis Lagrange who worked in numerous areas of mathematics.

1817-30

Non-Euclidean geometry

C. F. Gauss or János Bolyai or Nikolay Lobachevsky

1820

Electromagnetism

 

 

 

 

 

 

Quinine, purified

Hans Christian Oersted discovers that a pivoted magnetic needle turns at right angles to an object carrying an electric current during one of his classroom lectures; the word oersted enters into all European and American languages to indicate a unit of strength of a magnetic field. As a result, French mathematician and physicist André Marie Ampère creates mathematical principles relating the actions of electric currents and magnets.

 

South American Indians for centuries knew of the curative properties of cinchona bark to treat fevers particularly those caused by malaria. However, Pierre Pelletier and Joseph Caventou isolate and purify the active ingredient.

1822

Fourier analysis

Joseph Fourier

1827

Ohm’s law

Georg Ohm

1828

Synthesis of urea

Friedrich Wöhler

1831

Cell nucleus

Robert Brown

1834

Precursor of the germ theory of disease

Agostino Bassi is the first to show that a microorganism could cause disease; in the case of a fungal disease of silkworms, he demonstrates that it was contagious, could be transmitted naturally by direct contact, in infected food, or experimentally by means of a pin previously sterilized in a flame. In 1840, Friedrich G. J. Henle too proposes that microorganisms might directly cause disease. One of his student was Robert Koch.

1839

Cell theory of life

Theodor Schwann and Matthias Jakob Schleiden

1842

Doppler effect

Christian Doppler

1843

Nosocomial infections

Oliver Wendell Holmes Sr. notes that it was safer to give birth at home than in hospital, and postulated something present in a hospital is causing disease.

1845

Fungal blight

M.J. Berkeley shows that a fungus causes the Irish potato blight.

1848

Puerperal disease reduction

Ignaz Semmelweis, in charge of a lying-in hospital in Vienna, proves that puerperal fever can be reduced if physicians use calcium hypochlorite Ca(ClO)2 to wash their hands before treating patients. Chloride of lime washing reduced puerperal fever death rates.

1849

Electrical nature of nerve impulses

Emil Du Bois-Reymond

1850

Bacillus anthracis

Casimir Davaine observes little thread-like bodies in the blood of anthrax-killed animals.

1853

Hypodermic syringe

An Egyptian surgeon, as early as the 9th century, used a syringe device with a glass suction tube to remove cataracts from a patient, but Charles Gabriel Pravaz and Alexander Wood separately develop one with needles fine enough to pierce skin.

1854

Cholera epidemic etiology

 

Boolean algebra

John Snow deduces that the contaminated Broad Street Pump caused the cholera epidemic in London.

 

 George Boole

1856

Aniline dye

William Perkin

1859

Theory of evolution via natural selection

Charles Darwin publishes On the Origin of Species by Means of Natural Selection. In it, he challenges current dogmas about the creation of life on Earth. Darwin had worked as an unpaid naturalist aboard the HMS Beagle and the information he amassed on the voyage, particularly samples from the Galapagos Islands, was the stimulus for his theory of evolution by the means of natural selection. Contemporaneously, Alfred R. Wallace also conceives of natural selection as the driving force behind evolution.

1859-90

Germ theory

French chemist Louis Pasteur refutes the doctrine of spontaneous generation and discovers that specific microbes are disease causing. He believes that the causes of contagious diseases are similar to the causes of fermentation. He receives the title “father of bacteriology” for his efforts, which bring about a novel field of scientific inquiry.

    Robert Koch becomes the first scientist to develop a sequence of proofs utilized to confirm the germ theory of disease. Koch’s Postulates are published in 1890, and result from his work in which he proves that the bacterium Bacillus anthracis produces anthrax.*

1861

Speech center of the brain

Paul Broca

1864

Pasteurization

Louis Pasteur

1865

Chemical structure

August Kekule von Stradonitz deciphers the structure of the chemical benzene, and emphasizes the study of molecular structure in chemistry.

1866

Heredity, rules of

 

 

 

Math analysis, number theory, differential geometry, non-Euclidean geometry, and the “Riemann Hypothesis.”

Gregor Mendel, Austrian monk and botanist, determines how genetic information passes down the generations. In experiments on pea plants, he observes that a plant’s traits transmit to its offspring in a recessive or dominant manner.

 

Bernhard Riemann dies this year but leaves a lasting legacy in many fields of mathematics.

1867

Phenol as an

antiseptic

Joseph Lister introduces the use of phenol as an antiseptic: whether in surgical dressings, sprayed into the air, or applied directly it reduces wound infections dramatically.

1869

Periodic table of the elements

Dmitry Mendeleev and Lothar Meyer independently recognize that if one organizes each of the 63 identified elements by their atomic weight, their chemical characteristics recur in regular periodic groups. They independently devise the periodic table of the elements and Mendeleev predicts that other elements yet undiscovered must exist. Three of them are during his lifetime: gallium, scandium, and germanium.

1880

Vaccines, attenuated

Louis Pasteur and Charles Chamberland culture chicken cholera repeatedly, and find that it loses its virulence but can still confer immunity when injected.

1883

“Edison effect”

Thomas Edison uncovers a phenomenon that he calls “Etheric Force.” He discovers that a separate wire, grid, or plate put between the ends of the filament of an incandescent lamp works as a “damper” or valve to manipulate the flow of current. This discovery—together with his “carbon button” invention—contain the groundwork principles upon which the diode was subsequently invented, and upon which radio, television, and computer transistors are based!

1886-88

Radio waves

Heinrich Hertz

1887

Fractals

Giuseppe Peano

1892

Viruses

Dmitry Ivanovsky or Martinus Beijerinck

1894

Topology

Jules Henri Poincaré

1895

X-ray imaging

Wilhelm C. Röentgen

1896

Radioactivity

After Henri Becquerel finds radioactivity in uranium, Marie and Pierre Curie chemically separate it from its ore, and Marie observes that the remaining material is more “active” than the uranium itself. She surmises that the original ore contained new elements that are likewise radioactive.

1897

Aspirin

 

Electron

Felix Hoffmann (Bayer)

 

J.J. Thomson determines that the negatively charged particles discharged by cathode ray tubes are tiny and form a part of every atom. He names these particles, currently identified as electrons, “corpuscles.”

1898

Vitamins

Sir Frederick Hopkins et al. ascertain that deficiencies of particular nutrients cause certain diseases. Via feeding experiments on laboratory animals, Hopkins infers that these “accessory food factors” are vital to health.

    “In 1912,” writes Roger Bridgman “Polish biochemist Casimir Funk identified one of these in rice. Finding that it was . . . an amine, he proposed the name ‘vitamine.’”

1900–30

Quantum theory

“In 1900 physicists had some problems,” writes Roger Bridgman. “One was that the light from red-hot objects was not of the expected color. German physicist Max Planck found that he could predict the color correctly by assuming the energy was radiated only in multiples of a fixed amount, or quantum. This also explained why the energy of electrons ejected from metals by light depended on the color, not the brightness of the light.” Max Planck, Albert Einstein, Werner Heisenberg, Niels Bohr, and Erwin Schrödinger et al. create a counter-intuitive set of physical laws that explain the behavior of particles that form the structure of matter and transmit energy.

1901

Blood groups

Karl Landsteiner

1902

The hormone secretin is purified

Sir William Bayliss and Ernest Starling

1905

Function of chromosomes

Nettie Stevens or Edmund Wilson

1905-16

Relativity, special and general

 

Albert Einstein explains how clocks tick slower and objects appear to contract as they approach the speed of light, which overturns fundamental suppositions about time and space. His renowned formula E=mc² demonstrates that mass and energy are different expressions of the same thing (which is conserved), and that a tiny quantity of mass can be changed into an enormous amount of energy. One repercussion of his theory is that nothing with mass can ever exceed the speed of light.

    In 1916, he publishes the theory of General Relativity in which he posits that mass warps space-time and space-time directs the motion of matter-energy; consequently, large masses can bend the path of a beam of light. In 2016, gravitational waves, a prediction of the theory, were confirmed to exist.

1909

Nitrogen synthesis

 

Anti-syphilitic drug

Fritz Haber

 

Paul Ehrlich searches for a “magic bullet” that would poison pathogens but not patients. He develops Salvarsan, an arsenic compound against syphilis.

1910

Genes lie next to each other on chromosomes

 

 

 

 

 

Beginning this year, Thomas Hunt Morgan determines that genes reside on chromosomes. Performing his work on fruit flies, he infers that particular traits are linked to gender and that they are undoubtedly transmitted on one of the sex chromosomes (X or Y). He conjectures that additional genes are also transmitted on specific chromosomes. Utilizing the technique of chromosome recombination, he and his students map the positions of genes. Morgan and his students compose the formative book The Mechanism of Mendelian Heredity.

1911

Superconductors

Heike Kamerlingh Onnes discovers that certain materials offer no resistance to a current of electricity.

1912

Continental drift/plate tectonics

 

 

 

 

 

Alfred Wegener suggests that the continents of the world previously formed a solitary, huge landmass that ultimately fragmented in what has come to be termed “continental drift.” In 1962, Harry Hess proposes that continental drift is a consequence of seafloor spreading. By the 1960s, the research of numerous scientists reveals that the Earth’s surface is fragmented into many interlocking plates of rock. The grinding at plate boundaries creates mountains, volcanoes, and earthquakes.

1913

Electrons form chemical bonds

Niels Bohr publishes his theory of atomic configuration; electrons move in certain “quantized” orbits about the nucleus, and the quantity of electrons in an atom’s external shell mainly governs the chemical traits of that element.

1916

Black hole

Using the newly published theory of general relativity, Karl Schwarzschild theorizes that not even light can escape the clutches of a supermassive object that has collapsed to a point.

1917

Hybrid corn

Donald F. Jones

1920

Number theory

Death of Srinivasa Ramanujan who worked in this area

1921

Insulin, extraction and preparation of

Sir Frederick Grant Banting and Charles H. Best

1927

The universe is expanding

 

 

Big Bang theory

 

 

 

Uncertainty principle

Edwin Hubble ascertains the distance to numerous nearby galaxies and determines that the remoter the galaxy, the quicker they are racing away from us. His calculations show that the universe is expanding.

Taking his cue from Hubble, Georges Lemaître reasons that at some point in the remote past the universe must have occupied the size of a “primeval atom.”

 

Werner Heisenberg

1928

DNA is the genetic material

Oswald Avery demonstrates that DNA transmits genetic information.

1928–45

Penicillin

Alexander Fleming notes the inhibition of staphylococcus growth on plates contaminated with Penicillium notatum and dubs the compound produced by the fungus “penicillin”; Howard Florey and Boris Chain isolate and concentrate it, creating (not quite) the first antibiotic. Florey and Chain subsequently discover that it cures mice with bacterial infections, and Dorothy Hodgkin determines its chemical structure.

1929

Particle accelerator

 

Hubble’s constant (67.80 ± 0.77 (km/s)/Mpc)

Sir John D. Cockcroft and Ernest T. S. Walton

 

Edwin Hubble

1930

Genes control biochemical events

George Beadle and Edward Tatum conduct experiments on neurospora, a bread mold, and find that genes cause the production of enzymes.

1932

Neutron

 

Sulfa drugs

James Chadwick

 

Gerhard Domagk finds that Prontosil, an orange-red dye, cures infections produced by the common bacteria streptococci.

1937

The Krebs cycle

Hans Krebs details the numerous steps a cell takes to transform sugars, fats, and proteins into energy.

1938

Nuclear fission

Otto Hahn and Fritz Strassmann

1940

Blood bank

 

Jumping genes

Charles Richard Drew

 

Barbara McClintock finds transposons—genes that can jump on a chromosome—while pursuing an explanation for color differences in corn. These may trigger mutations and increase (or decrease) the quantity of DNA in the genome.

1941

Periodic ice ages

Serbian geophysicist Miultin Milankovitch advances a theory connecting the Earth’s motion to long-term environmental changes leading to ice ages. His theory postulates that cyclical deviations in the Earth-Sun geometry, for example orbit shape and axis angle, cause differing levels of solar energy to reach Earth.

1943

Axiomatic theory, invariant theory, algebraic number theory, class field theory, and functional analysis

Death of David Hilbert who contributed to each of these areas

1946

Carbon-14 dating

Willard F. Libby

 

1951-60

Contraceptives, oral

Carl Djerassi, Gregory Pincus, John Rock, and Min Chueh Chang

1953

DNA is a double helix

By 1944, Linus Pauling had determined that numerous proteins take the form of a spiral, like a coil spring, and hypothesized that so did DNA. In 1950, biochemist Erwin Chargaff discovered the ratio of certain nitrogen bases in DNA is always 1-to-1 when forming base pairs, and in 1952 Rosalind Franklin produced X-ray diffraction imagery implying that DNA was a helix.

    James Watson and Francis Crick propose that DNA is built from two chains of helically intertwined nucleotides. Crick suggests that matching base pairs bond together at the middle of the double helix to maintain a steady gap between the chains. They demonstrate that each of the strands serves as a template for the other, and that DNA can replicate itself without altering its structure, aside from sporadic errors or mutations.

1955-69

Insulin, structure of

Fred Sanger or Dorothy Hodgkin

1957

Nuclear forces

 

 

 

 

 

 

Pure and applied mathematics     

Chen-Ning Yang and Tsung-Dao Lee theorize, and Chien-Shiung Wu verifies, that the weak interaction “maximally violates parity.” Further discoveries of the basic forces at work on the subatomic level lead to the realization that every interaction in the universe results from one of four fundamental forces in nature—the strong force, the electromagnetic force, weak nuclear force, and gravitation.

 

Death of John von Neumann who advanced knowledge in these areas

1958

Van Allen radiation belt

James Van Allen

1960

Quasars

Allan Sandage

1961-66

Cracking the genetic code

Marshall Nirenberg heads one team, and Har Gobind Khorana heads another, that determines the genetic code, and demonstrates that a sequence of three nucleotide bases codes for each of the twenty amino acids.

1962

Quarks

Murray Gell-Mann

1964

Structure of t-RNA

 

Cosmic microwave background radiation

Robert William Holley

 

Arno Penzias and Robert Wilson detect the cosmic microwave background radiation, which they suspect is the afterglow of the big bang.

1966

Pulsars

Jocelyn Bell

1970

Restriction enzymes

 

 

Cloning, animal

Daniel Nathans, Werner Arber, and Hamilton O. Smith discover restriction enzymes—biological scissors that recognize and cut specific DNA sequences.

John B. Gurdon

1973

Genetic engineering

Herbert W. Boyer and Stanley N. Cohen

1974

Australo-pithecus Afarensis 

Donald Johanson unearths an incomplete skeleton of a 3.2 million-year-old female hominid in Ethiopia.

1976

RNA splicing

Phillip Allen Sharp and Richard J. Roberts et al. realize that for cells to make protein, DNA is initially transcribed into pre-messenger RNA. For unknown reasons, pre-messenger RNA molecules are subsequently spliced to make the final messenger RNA. In numerous genetic diseases, gene mutations produce mistakes in this RNA splicing procedure.

1977

Gene exons and introns

Phillip Sharp or Richard Roberts

1978

In vitro fertilization (IVF), human

 

Laetoli

footprints

Patrick Steptoe and Robert Edwards

 

 

A group led by Mary Leaky uncovers fossilized Australopithecus footprints at Laetoli, Tanzania. These footprints, acknowledged to be 3.5 million years old, were formed when two individuals walked over wet volcanic ash that later solidified into a kind of cement. These individuals moved with perfect two-footed strides proving that the hominids walked erect.

1980

K-T asteroid theory of dinosaur extinction

 

 

Protein targeting

 

G proteins

Walter Alvarez hypothesizes that elevated levels of iridium unearthed in rock core samples around the world provides evidence that an asteroid collision triggered the extinction of dinosaurs.

 

Günter Blobel

 

Martin Rodbell and Alfred Gilman

1981

Synthetic skin

Ioannis V. Yannas and John F. Burke

1983

HIV virus

Competing scientists Luc Montagnier (1983) and Robert Gallo (1984) separately discover a new retrovirus later dubbed HIV (human immunodeficiency virus), and determine that it is the causative agent of AIDS.

1984

DNA fingerprinting

 

Polymerase chain reaction

Alec Jeffreys determines that certain DNA sequences are exclusive to every individual, leading to the beginnings of DNA forensics.

 

Kary Mullis

1986

High-temperature super-conductors

Georg Bednorz and Alex Müller

1987

Vision correction, laser

Stephen Trokel

1988

Planets orbit other stars

Canadian astronomers Bruce Campbell, G. A. H. Walker, and S. Yang produce the first published finding that is later corroborated. Astronomers will later discover a multitude of extra solar planets due to better telescope technology although none yet looks like Earth.

1995

Proof of Fermat’s last theorem

Andrew Wiles

1998

RNA interference

 

 

 

 

Universal expansion is accelerating

Andrew Fire and Craig Mello detect RNA interference (RNAi), in which the existence of little pieces of double-stranded RNA (dsRNA) whose sequence complements a given gene inhibits the expression of that gene. Scientists think that dsRNAs that trigger RNAi may function as drugs in the future.

 

Adam Riess, Saul Perlmutter et al. are astonished that instead of decreasing due to the pull of gravity, the expansion of the universe at great distances is increasing.

2003

Humans have approximately 24,000 genes

Upon sequencing the human genome, it’s determined that humans have about 24,000 genes, far less than the majority of scientists had forecast. Scientists expect that understanding the genome will advance the disciplines of medicine and biotechnology, ultimately providing cures for diseases.

2012

Higgs boson

Peter Higgs and François Englert



* Koch was the first to demonstrate that a bacillary agent was a pathogen, and used criteria suggested to him by his teacher Henle that are now called Koch’s postulates. They are standards by which a bacterium may be said to cause a disease. 1. Microscopic examination must find the bacillus in the blood of all animals with anthrax. 2. A culture of a single colony-isolated bacillus must be made on solid media. (The idea for isolating pure cultures came from his observation of a spoiling cut potato. Also required, as developed in his lab by his assistant Friedrich Loeffler, were a nutrient broth and stains. Walther Hesse’s wife, Angelina Fannie, suggested using agar to solidify this medium on which to grow bacteria. Julius Petri developed shallow dishes for this culture.) 3. Inject the pure culture into healthy animals, and see if they get anthrax. 4. Isolate the same organism from animals experimentally given anthrax.