1905 in science

The year 1905 in science and technology involved some significant events, particularly in physics, listed below.

Albert Einstein

Astronomy

• January 2 – Charles Dillon Perrine at Lick Observatory discovers Elara, one of Jupiter's natural satellites.
• The Dominion Observatory opens in Ottawa.
• Various astronomers discover the minor planets 554 Peraga through 583 Klotilde (see List of minor planets/501–600).
• The nova V604 Aquilae appears in the constellation Aquila.
• The Umov effect is noted by Nikolay Umov.^[1]

Biology

• April 18 – William Bateson coins the term "genetics" in a letter to Adam Sedgwick.
• Reginald Punnett's Mendelism is published in Cambridge (U.K.), probably the first popular science book on genetics.
• Frederick Blackman proposes his law of limiting factors in relation to photosynthesis.^[2]
• Nettie Stevens and Edmund Beecher Wilson independently describe the XY sex-determination system.
• Stamen Grigorov identifies the bacterium Lactobacillus bulgaricus, a major agent in the creation of yogurt.
• Maltese doctor and archaeologist Themistocles Zammit identifies unpasteurized milk as the major source of the pathogen causing Brucellosis.
• National Association of Audubon Societies for the Protection of Wild Birds and Animals established in the United States.

Chemistry

• Carl von Linde obtains pure liquid oxygen and nitrogen by cooling air.^[3]
• Alfred Einhorn synthesises the local anesthetic novocaine.^[4]
• The first commercial use of the Frank–Caro process for the nitrogen fixation reaction of calcium carbide and atmospheric nitrogen to produce calcium nitrate as a fertilizer.^[3]
• Fritz Haber and Carl Bosch develop the Haber process for making ammonia from its elements, a milestone in industrial chemistry with deep consequences in agriculture.

Mathematics

• Pierre Fatou defines the Mandelbrot set.
• Oswald Veblen proves the Jordan curve theorem.
• Martin Kutta describes the popular fourth-order Runge-Kutta method.
• James Cullen, S.J., begins the study of Cullen numbers.
• Emanuel Lasker proves the Lasker–Noether theorem for the special case of polynomial rings.
• Karl Pearson proposes the random walk in a letter to Nature (journal).

Paleontology

• The Saurian Expedition led by John C. Merriam recovers many specimens of ichthyosaur.
• Tyrannosaurus rex is described and named by Henry Fairfield Osborn.

Physics

• Albert Einstein publishes his four Annus Mirabilis papers. In particular, he formulates the theory of special relativity and states the law of mass-energy conservation: E = mc². He also explains the photoelectric effect by quantization and mathematically analyzes Brownian motion. Because of this, 1905 is said to be the miraculous year for physics, and its 100th anniversary (2005) was declared the World Year of Physics.

Physiology and medicine

• Nikolai Korotkov first describes auscultatory blood pressure measurement.^[5]
• Karl Landsteiner first describes Meconium ileus.^[6]
• Fritz Schaudinn and Erich Hoffmann discovered the bacterium that was responsible for syphilis, a spiral-shaped spirochete called Treponema pallidum.

Psychology

• Sigmund Freud publishes Drei Abhandlungen zur Sexualtheorie (Three Essays on the Theory of Sexuality) and Der Witz und seine Beziehung zum Unbewußten (Jokes and their Relation to the Unconscious).
• June – Alfred Binet and Théodore Simon publish the first Binet-Simon Intelligence Test for intelligence testing of children with mental retardation.^[7]

Technology

• Pathé Frères colorise black-and-white films by machine.
• Alfred Buchi files a patent for the turbocharger.
• Paul de Vivie invents a two-speed rear-wheel derailleur gear for bicycles.^[8]
• Pipe manufactures the first automobile with a hemi engine.
• Walter Griffiths invents a manually powered domestic vacuum cleaner.
• Reginald Fessenden invents the superheterodyne receiver.^[9]
• First bascule bridge to the design of Joseph Strauss built.^[10]
• Canal Lake Concrete Arch Bridge built in Ontario.

Awards

• Nobel Prizes
  • Physics – Philipp Eduard Anton von Lenard
  • Chemistry – Johann Friedrich Wilhelm Adolf von Baeyer
  • Medicine – Robert Koch

Births

• February 1 – Emilio G. Segrè (died 1989), physicist, Nobel laureate
• February 17 – Rózsa Péter (died 1977), mathematician, "founding mother of recursive function theory"
• February 23 – Derrick Henry Lehmer (died 1991), mathematician
• March 18 – Thomas Townsend Brown (died 1985), American inventor
• March 27 – Elsie MacGill (died 1980), aeronautical engineer, "Queen of the Hurricanes"
• April 13 – Bruno Rossi (died 1993), physicist and astronomer
• April 18 – George H. Hitchings (died 1998), scientist, Nobel laureate in Medicine
• April 20 – Albrecht Unsöld (died 1995), astronomer
• July 7 – Marie-Louise Dubreil-Jacotin (died 1972), mathematician
• August 1 – Helen Sawyer Hogg (died 1993), astronomer
• August 11 – Erwin Chargaff (died 2002), biochemist
• August 16 – Marian Rejewski (died 1980), mathematician and cryptologist
• August 31 – Robert Bacher (died 2004), nuclear physicist
• September 3 – Carl David Anderson (died 1991), physicist, Nobel laureate
• September 17 – Hans Freudenthal (died 1990), mathematician
• September 22 – Eugen Sänger (died 1964), aerospace engineer
• September 24 – Severo Ochoa (died 1993), biochemist, Nobel laureate
• September 30 – Nevill Francis Mott (died 1996), physicist, Nobel laureate
• October 15 – C. P. Snow (died 1980), physicist and novelist
• October 22 – Karl Guthe Jansky (died 1950), physicist
• October 22 – Albert Whitford (died 2002), astronomer
• October 23 – Felix Bloch (died 1983), physicist, Nobel laureate
• October 31 – Harry Harlow (died 1981), psychologist
• November 10 – Louis Harold Gray (died 1965), English physicist, inventor of the field of radiobiology
• December 7 – Gerard Kuiper (died 1973), astronomer
• December 16 – Piet Hein (died 1996), mathematician
• December 22 – Tommy Flowers (died 1998), computer engineer

Deaths

• January 4 – Paul Henry (born 1848), astronomer
• January 14 – Ernst Abbe (born 1840), physicist
• March 24 – Jules Verne (born 1828), science fiction author
• April 14 – Otto Wilhelm von Struve (born 1819), astronomer
• June 18 – Per Teodor Cleve (born 1840), chemist
• August 20 – Franz Reuleaux (born 1829), mechanical engineer
• September 19 – Thomas Barnardo (born 1845), physician and philanthropist
• October 6 – Ferdinand von Richthofen (born 1833), geologist
• November 14 – Robert Whitehead (born 1823), marine engineer
• November 15 (O.S. November 2) – Ivan Sechenov (born 1829), "the father of Russian physiology"

References