German poet Johann Wolfgang von Goethe writes The Morphology of Plants stating that all plant organs, flowers included, began as leaves — an assertion that will enjoy some support from 21st-century genetic research.

British doctors find that snuff leads to increased risk of nose cancer.

Luigi Galvani announces that electricity applied to severed frog's legs causes them to twitch and that frogs legs twitch in the presence of two different metals with no electric current present. The latter discovery eventually leads to Alessandro Volta's developing the electric battery.

Pierre Prévost develops his theory of exchanges of radiation of heat. He correctly shows that cold is merely the absence of heat and that all bodies continually radiate heat. If they seem not to radiate heat, it means that they are in heat equilibrium with their environment.

Charles Babbage is Born

John Stone, Concord, Massachusetts, patents a pile driver.

New York City traffic regulation creates first one-way street.

Guillotine first used (to execute highwayman Nicolas J. Pelletier).

Reverend James Douglas publishes Nenia Britannica; or, A Sepulchral History of Great Britain providing perhaps the first record of a fossil (sea urchin) at an archaeological site.

France becomes first country to use the metric system.

Eli Whitney invents the cotton gin (cotton enGINe), a machine that quickly and easily separates cotton fibers from their seeds, allowing for much greater productivity than manual cotton separation. By reducing the labor of removing seeds, the cotton gin made cotton growing more profitable, thereby raising demand for slave labor. The first federal census of 1790 counted 697,897 slaves; by 1810, there were 1.2 million slaves, a 70 percent increase. Slavery spread from the seaboard to some of the new western territories and states as new cotton fields were planted, and by 1830 it thrived in more than half the continent. Within 10 years after the cotton gin was put into use, the value of the total United States crop leaped from $150,000 to more than $8 million.

John Frere describes and illustrates handaxes from Hoxne that will turn out to be some 400,000 years old.

Erasmus Darwin (Charles' grandfather) publishes Zoonomia, or the Laws of Organic Life.

James Hutton publishes An Investigation of the Principles of Knowledge. Buried in the 2,138-page philosophical tome is a chapter about variety in nature in which Hutton anticipates Charles Darwin's theory of natural selection.

John Dalton's Extraordinary facts relating to the vision of colors gives an early account of red-green color blindness, which he refers to as Daltonism, since he is afflicted with the condition.

Zoonomia, or the Laws of Organic Life by Erasmus Darwin (grandfather of Charles Darwin) contains his ideas about evolution, which are Lamarckian in that they assume the environment has a direct influence on organisms, causing permanent changes in the germ line.

Alessandro Volta demonstrates that the electric force observed by Galvani is not connected with living creatures, but can be obtained whenever two different metals are placed in a conducting fluid.

James Hutton's Theory of the Earth published, interpreting certain geological strata as former sea beds. Hutton proposes geological theory of gradualism.

Johann Friedrich Blumenbach publishes De generis humani varietate nativa liber arguing that humans comprise a single species with five varieties: Caucasian, Mongolian, Ethiopian, (American) Indian and Malayan.

James Hutton overturns the "Neptunian" view of rock formation in his Theory of the Earth, suggesting instead that forces of rock creation are balanced by forces of rock destruction.

(no entry for this year)

(no entry for this year)

Publication of Thomas Malthus' Essay on the Principle of Population, a work that Darwin asserted helped him frame the principle of evolution by natural selection.

Henry Cavendish determines the mass of Earth by measuring the gravity between two small masses and two large masses. This gives the gravitational constant G, which was the only unknown in Newton's equations. Solving for G enables Cavendish to establish that Earth is about 5.5 times as dense as water.

Enquiry concerning the source of heat which is excited by friction by Count Rumford (Benjamin Thompson) describes his experiments with boring cannons that show that the caloric theory of heat cannot be true, and that heat should be considered a kind of motion.

The first mammoth fossil fully documented by modern science is discovered near the delta of the Lena River in 1799 by Ossip Schumachov, a Siberian hunter. Schumachov allows it to thaw (a process taking several years) until he can retrieve the tusks for sale to the ivory trade in Yakutsk. He then abandons the specimen, allowing it to decay before its recovery. In 1806, Russian botanist Mikhail Adams rescues what remained of the specimen and brought it to the Zoological Museum of the Zoological Institute of the Russian Academy of Sciences in St. Petersburg. The specimen, which became known as the Adams Mammoth, is stuffed and mounted, and continues to be on display at the Zoological Institute.

Charles White publishes An Account of the Regular Gradation in Man, and in Different Animals and Vegetables, a treatise on the great chain of being, showing people of color at the bottom of the human chain.

Faujas publishes a description of the Maastricht animal, a spectacular mosasaur found in chalk quarries in the Netherlands, describing it as a crocodile.

Thomas Jefferson publishes a paper describing Megalonyx, a North American fossil ground sloth similar to the one found in South America.

George Shaw publishes a description of a platypus even though he suspects the odd animal might be a hoax.

Alexander von Humboldt names the Jurassic System, after the Jura Mountains. This time period will later be identified as the "middle period" for the dinosaurs.

William Smith maps rock formations in the vicinity of Bath, England, making perhaps the world's first geologic map. The same year, Smith, Joseph Townsend and Benjamin Richardson recognize rocks containing the Permian and Triassic, though not necessarily by those names. (These periods will later be identified as spanning the Earth's most catastrophic mass extinction.)

The British government purchases the collection of Scottish anatomist John Hunter, forming the Hunterian Museum.