1893 in science

Biology

• July 11 – Kōkichi Mikimoto, in Japan, develops the method to seed and grow cultured pearls.
• Henry Luke Bolley discovers a method of treating smut with formaldehyde.

  Chemistry

• Hans Goldschmidt discovers the thermite reaction.
• Nagai Nagayoshi synthesizes methamphetamine from ephedrine.
• Alfred Werner discovers the octahedral structure of cobalt complexes, thus establishing the field of coordination chemistry.

  Earth sciences

• Eduard Suess postulates the former existence of the Tethys Sea.

  Exploration

• Mary Kingsley lands in Sierra Leone on the first of her journeys through Africa in the interests of anthropology and natural history.

  Mathematics

• Geometric Exercises in Paper Folding by T. Sundara Row is first published in Madras.

  Medicine

• July 9 – Daniel H. Williams completes the first successful open heart surgery.
• October 5 – Johns Hopkins Medical School opens in the United States.
• Emil Kraepelin introduces the concept of dementia praecox in the classification of mental disorders, distinguishing it from mood disorder in his Lehrbuch der Psychiatrie.
• Ádám Politzer describes otosclerosis for the first time.
• Vladimir Bekhterev describes Ankylosing spondylitis.

  Physics

• Wilhelm Wien formulates Wien's displacement law.

  Technology

• January 2 – Webb C. Ball introduces railroad chronometers which become the general railroad timepiece standards in North America.
• February 1 – Thomas Edison finishes construction of the first motion picture studio in West Orange, New Jersey.
• February 11 – János Csonka and Donát Bánki apply for a patent for the carburetor in Hungary.
• February 23 – Rudolf Diesel receives a patent for the diesel engine. In this year he also publishes his treatise Theorie und Konstruktion eines rationellen Wärmemotors zum Ersatz der Dampfmaschine und der heute bekannten Verbrennungsmotoren.
• February 28 – Edward Goodrich Acheson patents the method for making the abrasive silicon carbide powder.
• May 9 – Edison's 1½ inch system of Kinetoscope is first demonstrated in public at the Brooklyn Institute.
• May – William Scherzer files a patent for his design of rolling lift bridge.
• June 21 – The first Ferris Wheel opens to the public at the World's Columbian Exposition in Chicago.
• July 25 – Completion of the Corinth Canal in Greece.
• August 17 – Wilhelm Maybach patents the spray nozzle carburetor in France.
• Scottish scientist Alan MacMasters invents the first electric bread toaster.
• Refinery for Pacific Coast Borax Company in Alameda, California, designed by Ernest L. Ransome, is the first major reinforced concrete building in the United States.

  Awards

• Copley Medal: George Gabriel Stokes
• Wollaston Medal for Geology: Nevil Story Maskelyne

  Births

• February 3 – Gaston Julia, French mathematician.
• April 29 – Harold Urey, American winner of the Nobel Prize in Chemistry.
• April 30 – Roy Chadwick, English aircraft designer.
• June 13 – Alan A. Griffith, English stress engineer.
• August 5 – Sydney Camm, English aircraft designer.
• August 15 – Leslie Comrie, New Zealand astronomer and computing pioneer.
• August 24 – Haim Ernst Wertheimer, German Jewish biochemist.
• August 25 – Henry Trendley Dean, American dental researcher.
• September 16 – Albert Szent-Györgyi, Hungarian physiologist, winner of the Nobel Prize in Physiology or Medicine.
• October 23 – Ernst Öpik, Estonian astronomer and astrophysicist.
• November 3 – Edward Adelbert Doisy, American biochemist, winner of the Nobel Prize in Physiology or Medicine.
• December – Eugène Gabritschevsky, Russian biologist and artist.

  Deaths

• January 2 – John Obadiah Westwood, English entomologist.
• January 7 – Jožef Stefan, Slovenian physicist and mathematician.
• March 3 – Orlando Whistlecraft, English meteorologist.
• August 16 – Jean-Martin Charcot, French neurologist.
• September 1 – Leonard Jenyns, English natural historian.
• December 4 – John Tyndall, British physicist.
• December 6 – Rudolf Wolf, Swiss astronomer.
• December 25 – Marie Durocher, Brazilian obstetrician and physician.
• December 28 – Richard Spruce, English botanist.