1808 in science

Astronomy

• December 9 – Mercury occults Saturn.

Chemistry

• Barium, calcium, magnesium, and strontium isolated by Humphry Davy.
• Joseph Louis Gay-Lussac formulates the law of combining volumes for gases.
• John Dalton begins publication of A New System of Chemical Philosophy, explaining his atomic theory of chemistry and including a list of atomic weights.
• Jöns Jakob Berzelius publishes Lärbok i Kemien in which he proposes modern chemical symbols and notation, and of the concept of relative atomic weight.

Mathematics

• French mathematician Christian Kramp introduces the notation n! in factorials.
• German mathematician Carl Friedrich Gauss publishes Theorematis arithmetici demonstratio nova, introducing Gauss's lemma in the third proof of quadratic reciprocity.
• Irish American mathematician Robert Adrain produces a formulation of the method of least squares.

Medicine

• The term "psychiatry" is first coined by German physician Johann Christian Reil.
• The early medical journal Bibliotek for Læger begins publication in Denmark.

Natural history

• January 12 – Organizational meeting leading to creation of the Wernerian Natural History Society is held in Edinburgh.
• Alexander von Humboldt publishes his Ansichten der Natur.

Technology

• February 11 – Anthracite coal is first burned as fuel by Jesse Fell in Wilkes-Barre, Pennsylvania; the discovery leads to the use of coal as a key fuel source of the Industrial Revolution in the United States.
• August 24 – William Congreve patents the Congreve clock with a rolling ball regulator.
• Bryan Donkin patents a steel nib pen in England.
• John Heathcoat is granted his first patent for a bobbinet lace machine in England.

Awards

• Copley Medal: William Henry
• Joseph-Louis Lagrange is appointed by Napoleon as a Grand Officer of the Legion of Honour and a Comte of the French Empire.

Births

• February 29 – Hugh Falconer, Scottish-born geologist, botanist, paleontologist and paleoanthropologist.
• April 13 – Antonio Meucci, Italian-born inventor.
• May 9 – John Scott Russell, Scottish-born naval architect and shipbuilder.
• July 8 – George Robert Gray, English zoologist.
• July 25 – Johann Benedict Listing, German mathematician.
• August 4 – Johann Ritter von Oppolzer, Austrian physician.
• October 29 – Caterina Scarpellini, Italian astronomer.
• November 6 – Friedrich Julius Richelot, German mathematician.
• Anne Elizabeth Ball, Irish|Irish phycologist.

Deaths

• March 3 – Johan Christian Fabricius, Danish entomologist.
• May 18 – Rev. Elijah Craig, American inventor of bourbon whiskey.
• October 8 – John Sheldon, English anatomist.
• October 21 – Maria Christina Bruhn, Swedish inventor.
• December 24 – Thomas Beddoes, reforming English physician.