1841 in science

Biology

• Rev. Miles Joseph Berkeley demonstrates that Phytophthora infestans is a fungal infection.
• Royal Botanic Gardens, Kew, first open to the public and William Hooker appointed director.
• John Gould begins publication of A Monograph of the Macropodidae, or Family of Kangaroos.

  Chemistry

• Theobromine is first discovered in cacao beans by Russian chemist Alexander Woskresensky.
• Uranium is first isolated, by Eugène-Melchior Péligot.
• Chemical Society of London founded by Thomas Graham.
• Reinsch test for heavy metals discovered by Hugo Reinsch.

  Exploration

• January 27 – The active volcano Mount Erebus in Antarctica is discovered and named by James Clark Ross.
• January 28 – Ross discovers the "Victoria Barrier", later known as the Ross Ice Shelf.
• Ross additionally discovers the Ross Sea, Victoria Land and Mount Terror.

  Geology

• Hugh Miller publishes The Old Red Sandstone.
• The first comprehensive geological map of France is published by Dufrénoy and Élie de Beaumont, the result of thirteen years of investigations.

  Human sciences

• November 13 – Scottish surgeon James Braid attends his first demonstration of animal magnetism which leads to Braid's study of the subject he eventually calls hypnotism.

  Mathematics

• Prussian mathematician Karl Weierstrass discovers but does not publish the Laurent expansion theorem.
• English mathematician William Rutherford calculates an approximation of π to 208 decimal places of which the first 152 are correct.

  Physiology and medicine

• Platelets are first described from microscopic observation by George Gulliver.

  Technology

• February – H. Fox Talbot obtains a patent in the United Kingdom for the calotype process in photography.
• April 16 – Loring Coes patents the screw type wrench commonly known as the monkey wrench in the United States.
• April 24 – Squire Whipple patents the iron bowstring arch through truss bridge in the United States.
• Draughtsman William Howe and pattern-maker William Williams of Robert Stephenson and Company in Newcastle upon Tyne originate Stephenson valve gear for the steam locomotive.
• Joseph Whitworth introduces the British Standard Whitworth system of screw threads in his paper On a Uniform System of Screw Threads.
• American artist John G. Rand invents the collapsible zinc oil paint tube, marketed by Winsor & Newton of London.

  Awards

• Copley Medal: Georg Ohm
• Wollaston Medal: Adolphe Theodore Brongniart

  Births

• January 29 – Henry Morton Stanley, explorer, journalist.
• February 2 – François-Alphonse Forel, pioneer in the study of lakes.
• February 4 – Clément Ader, engineer and inventor, airplane pioneer.
• February 24 – Carl Gräbe, chemist.
• March 6 – Alfred Cornu, physicist.
• August 4 – W. H. Hudson, naturalist.
• August 25 – Emil Theodor Kocher, 1909 winner of the Nobel Prize in Physiology or Medicine
• October 12 – Joseph O'Dwyer, physician
• October 26 – Theodor von Oppolzer, astronomer.
• November 3 – Eugen Warming, botanist and founder of ecology.
• December 29 - Rosalie Fougelberg, Swedish dentist

  Deaths

• May 16 – Marie Boivin, French midwife, inventor and obstetrics writer
• May 31 – George Green, English mathematician.
• August 18 – Louis de Freycinet, explored coastal regions of Western Australia.
• September 9 – Augustin Pyramus de Candolle, Swiss botanist.
• October 28 – Johan August Arfwedson, Swedish chemist.