1842 in science

Botany

• Nathaniel Bagshaw Ward publishes On the Growth of Plants in Closely Glazed Cases in London, promoting his concept of the Wardian case.

  Exploration

• Antarctic explorer James Clark Ross charts the eastern side of James Ross Island and on January 23 reaches a Farthest South of 78°09'30"S.

  Medicine

• January – American medical student William E. Clarke of Berkshire Medical College becomes the first person to administer an inhaled anesthetic to facilitate a surgical procedure.
• March 30 – American physician and pharmacist Crawford Long administers an inhaled anesthetic to facilitate a surgical procedure.
• English surgeon William Bowman publishes On the Structure and Use of the Malpighian Bodies of the Kidney, identifying Bowman's capsule, a key component of the nephron.
• Edwin Chadwick's critical Report on an inquiry into the Sanitary Condition of the Labouring Population of Great Britain is published by the Poor Law Commission.

  Paleontology

• Palaeontologist Richard Owen coins the name Dinosauria, hence the Anglicized dinosaur.

  Physics

• Christian Doppler proposes the Doppler effect.
• Julius Robert von Mayer proposes that work and heat are equivalent. This is independently discovered in 1843 by James Prescott Joule, who names it "mechanical equivalent of heat".

  Technology

• January 8 – Delft University of Technology established by William II of the Netherlands as a 'Royal Academy for the education of civilian engineers'.
• February 21 – John Greenough is granted the first U.S. patent for the sewing machine.
• June – James Nasmyth patents his design of steam hammer in England and introduces an improved planing machine.

  Events

• September 14–17 – English naturalist Charles Darwin and his family settle at Down House in Kent.

  Awards

• Copley Medal: James MacCullagh
• Wollaston Medal: Leopold von Buch

  Births

• February 2 – Julian Sochocki, Polish mathematician.
• February 22 – Camille Flammarion, French astronomer.
• March 17 – Rosina Heikel, Finnish physician.
• April 4 – Édouard Lucas, Belgian physician.
• May 8 – Emil Christian Hansen, Danish fermentation physiologist.
• June 11 – Carl von Linde, German refrigeration engineer.
• August 23 – Osborne Reynolds, Irish-born physicist.
• September 9 – Elliott Coues, American ornithologist.
• September 20
• * James Dewar, Scottish-born chemist.
• * Charles Lapworth, English geologist.
• October 17 – Gustaf Retzius, Swedish anatomist.
• October 24 – Nikolai Menshutkin, Russian chemist.
• November 12 – John William Strutt, 3rd Baron Rayleigh, English Nobel Prize-winning physicist.
• December 3 – Ellen Swallow Richards, American chemist.
• December 17 – Sophus Lie, Norwegian mathematician.

  Deaths

• February 15 – Archibald Menzies, Scottish-born botanist.
• April 28 – Charles Bell, Scottish-born anatomist.
• May 8 – Jules Dumont d'Urville, French explorer.
• June 9 - Maria Dalle Donne, Bolognese physician
• June 30 – Thomas Coke, Earl of Leicester, English agriculturalist and geneticist.
• July 19 – Pierre Joseph Pelletier, French chemist.
• July 25 – Dominique Jean Larrey, French military surgeon, pioneer of battlefield medicine.