The year 1893 in science and technology involved some significant events, listed below.

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.^[1]
• Nagai Nagayoshi synthesizes methamphetamine from ephedrine.
• Alfred Werner discovers the octahedral structure of cobalt complexes, thus establishing the field of coordination chemistry.^[2]

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

• J. J. Sylvester poses what becomes known as the Sylvester–Gallai theorem in geometry.^[3]
• 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 (4th edition).
• Ádám Politzer describes otosclerosis for the first time.
• Vladimir Bekhterev describes Ankylosing spondylitis.^[4]

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.^[5][6]
• 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.^[7]
• May 9 – Edison's 1½ inch system of Kinetoscope is first demonstrated in public at the Brooklyn Institute.
• May – William Scherzer (dies July 20) files a patent for his design of rolling lift bridge.^[8]
• June 21 – The first Ferris Wheel opens to the public at the World's Columbian Exposition in Chicago.^[9][10]
• July 12 – Prototype of Diesel's Motor 250/400 (150/400) completed;^[11] first run August 10 (on petrol).^[12]
• July 25 – Completion of the Corinth Canal in Greece.^[13]
• August 17 – Wilhelm Maybach patents the spray nozzle carburetor in France.^[6]
• 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.^[14]
• The first sousaphone is built by James Welsh Pepper at the request of bandmaster John Philip Sousa in the United States.^[15]

Awards

• Copley Medal: George Gabriel Stokes^[16]
• Wollaston Medal for Geology: Nevil Story Maskelyne

Births

• February 3 – Gaston Julia (died 1978), French mathematician.
• February 24 – Tokushichi Mishima (died 1975), Japanese inventor and metallurgist.
• April 29 – Harold Urey (died 1981), American winner of the Nobel Prize in Chemistry.
• April 30 – Roy Chadwick (died 1947), English aircraft designer.
• June 13 – Alan A. Griffith (died 1963), English stress engineer.
• August 5 – Sydney Camm (died 1966), English aircraft designer.
• August 15 – Leslie Comrie (died 1950), New Zealand astronomer and computing pioneer.
• August 24 – Haim Ernst Wertheimer (died 1978), German Jewish biochemist.
• August 25 – Henry Trendley Dean (died 1962), American dental researcher.
• September 16 – Albert Szent-Györgyi (died 1986), Hungarian physiologist, winner of the Nobel Prize in Physiology or Medicine.
• October 23 – Ernst Öpik (died 1985), Estonian astronomer and astrophysicist.
• November 3 – Edward Adelbert Doisy (died 1986), American biochemist, winner of the Nobel Prize in Physiology or Medicine.
• December 3 – Wilhelm Pelikan (died 1981), Austrian chemist.
• December 14 – Alf Lysholm (died 1973), Swedish mechanical engineer.
• December – Eugène Gabritschevsky (died 1979), Russian biologist and artist.

Deaths

• January 2 – John Obadiah Westwood (born 1805), English entomologist.
• January 7 – Jožef Stefan (born 1835), Slovenian physicist and mathematician.
• March 3 – Orlando Whistlecraft (died 1810), English meteorologist.
• August 16 – Jean-Martin Charcot (born 1825), French neurologist.
• September 1 – Leonard Jenyns (born 1800), English natural historian.
• November 6 - Justin Benoît, (born 1813), French surgeon and anatomist^[17]
• December 4 – John Tyndall (born 1820), British physicist.
• December 6 – Rudolf Wolf (born 1816), Swiss astronomer.
• December 25 – Marie Durocher (born 1809), Brazilian obstetrician and physician.
• December 28 – Richard Spruce (born 1817), English botanist.