Charles Lyell's multi-volume Principles of Geology appear (between 1830 amd 1833), advancing the theory of uniformitarianism, i.e., the view that geological formations are explainable in terms of forces and conditions observable at present.

Georg Goldfuss announces that he sees "hairs" on a pterosaur fossil. This outlandish assertion will be supported by later finds.

The first edition of Birds of America, by the painter and ornithologist John James Audubon (1785-1851), appears.

Charles Darwin joins the crew of the HMS Beagle as the ship's naturalist. The Beagle plans a two-year voyage to map the coast of South America. This turns out to be a five-year trip.

Patrick Matthew publishes On Naval Timber and Arboriculture with an appendix describing what Charles Darwin will later name natural selection. After becoming aware of Matthew's hypothesis, Darwin will acknowledge it in a reprint of On the Origin of Species.

Robert Brown published his observations reporting the discovery and widespread occurrence of nuclei in cells.

Independently, Michael Faraday and Joseph Henry discover that electricity can be induced by changes in a magnetic field (electromagnetic induction), a discovery leading to the first electric generators.

Encouraged by Cambridge professor William Whewell, the Royal Society of London commissions reports of manuscripts received. This move will later be cited as the beginning of the peer-review process.

Gideon Mantell finds the first fossil Hylaeosaurus, an ankylosaur. He will formally name it the following year, making it the third identified dinosaur species.

In November, the New York and Harlem Railroad begins service, and heralds the start of rapid mass transit in New York City. Two horse-drawn rail cars operate every 15 minutes between 14th Street and Prince Street, along the Bowery. The fare is 25 cents.

Solicitor André Brouillet discovers a reindeer bone with an engraved illustration of two female deer in Chaffaud Cave. He assumes the carving was made by the Celts. Later research will show the artwork to be about 13,000 years old.

The first volume of the five-volume Recherches sur les poissons fossiles (Researches on Fossil Fishes) by Jean-Louis-Rodolphe Agassiz is published.

The English term SCIENTIST is coined by the philosopher William Whewell (1794-1866 ), during a meeting of the British Association for the Advancement of Science.

In correspondence, Michael Faraday and William Whewell introduce the terms ELECTRODE, ANODE, ION, CATHODE, ANION, CATION, ELECTROLYTE, and ELECTROLYSIS.

Ada Lovelace Meets Charles Babbage

Based on a vertebrae and other fragments from Alabama, anatomist Richard Harlan identifies Basilosaurus as a fossil reptile. It will later be identified as a fossil whale.

Friedrich von Alberti names the Triassic System. This time period will later by identified with the first dinosaurs.

Mathematician Carl Friedrich Gauss (1777-1855) shows that the origin of the Earth's magnetic field must lie deep inside the Earth. He makes use of the measurements of the magnetic field made by the physicist Paul Erman in 1828.

H rcules Florence, a French-Brazilian painter and the isolate inventor of photography in Brazil, coined the word photographie for his technique, at least four years before John Herschel coined the English word photography.

Charles Babbage invents the "analytical engine" — the forerunner of the modern computer.

While serving as scientific officer on the HMS Beagle, Charles Darwin visits the Galapagos Islands. He observes that the many varieties of finches on the islands seem to have developed from a common ancestor found on the mainland of South America.

Adam Sedgwick names the Cambrian System, recognizing the first rich assemblage of fossils in the rock record. Roderick Murchison names the Silurian System. He believes (not entirely accurately) that the Silurian predates the fossils of land plants, and consequently any economically valuable coal seams. Murchison and Sedgwick will later develop a bitter priority dispute over these systems.

Gustave-Gaspard Coriolis's Mémoire sur les equations du mouvement relatif des sytèms de corps (Memoir on the equations of relative movement of systems of bodies) describes the Coriolis effect: the deflection of a moving body caused by Earth's rotation. The Coriolis effect is important in the study of wind. However, the claim that the Coriolis effect determines the direction water rotates when going down a drain is a myth.

Henry Fox Talbot produces durable silver chloride camera negatives on paper and conceives the two-step negative-positive procedure used in most non-electronic photography up to the present.

Mappa Selenographica, a map of the moon's surface, is produced by the astronomers Wilhelm Beer (1797-1850) and Johann Heinrich von Mädler (1794-1874). The two will also be the first to map Mars.

Henry Riley and Samuel Stutchbury name Thecodontosaurus, the fourth named dinosaur species.

Elements of Botany, by the naturalist Asa Gray (1810-1888), is published. It is the first botanical textbook.

German biologist Theodor Schwann discovers the enzyme pepsin — the first known animal enzyme. He reports the discovery in Über das Wesen der Verdauungsprozesses (On the essence of digestion).

John Frederic Danielle invents the Daniell cell, the first reliable source of electric current, based on the interactions of copper and zinc.

Alonzo D. Phillips, a shoemaker from Springfield, Massachusetts, patents the phosphorous match.

Charles Darwin formulates the theory of natural selection to explain evolution. Fearful of the reaction his theory will cause, he delays publishing.

Hermann von Meyer names Plateosaurus, the fifth named dinosaur species.

Louis Agassiz presents the theory of the Ice Age at a meeting of the Swiss Society of Natural Sciences. The shocked audience reacts with hostility.

Mathematician Semèon Denis Poisson (1781-1840) publishes Recherches sur la Probabilitè des Jugements. Poisson's book described what is now known as the Poisson Distribution, for the first time.

Charles Babbage published a paper describing a mechanical computer that is now known as the Analytical Engine

Samuel F. B. Morse sends his first message by electric telegraph — "What hath God wrought!" — on an experimental line between Washington DC and Baltimore, Maryland.

M. J. Schleiden and T. Schwann develop the cell theory. Schleiden notes nucleoli within nuclei.

Chemist Jöns Jakob Berzelius (1779-1848) shows that the presence of iron is what enables blood to absorb as much oxygen as it does.

The word PROTEIN first appears in the chemical literature in a paper by G. J. Mulder. The term, however, was invented by J. J. Berzelius.

The S.S. Sirius and the S. S. Great Western are the first ships powered entirely by steam to cross the Atlantic. Both ships are designed by engineer Isambard Kingdom Brunel (1806-1859).

Czech scientist Jan Evangelista Purkyně (also written Johannes Evangelist Purkinje) coins the word PROTOPLASM to describe the contents of a cell.

Roderick Murchison and Adam Sedgwick name the Devonian System.

The English scientist Michael Faraday concludes from his work on electromagnetism that, contrary to scientific opinion of the time, the divisions between the various kinds of electricity are illusory. He also establishes that magnetism can affect rays of light, and that there is an underlying relationship between the two phenomena.

Louis-Jacques-Mand Daguerre perfects and presents the daguerreotype process as the first publicly available photographic process (which for nearly twenty years was also the one most commonly used). To make the image, a daguerreotypist would polish a sheet of silver-plated copper to a mirror finish, treat it with fumes that made its surface light sensitive, expose it in a camera for as long as was judged to be necessary, which could be as little as a few seconds for brightly sunlit subjects or much longer with less intense lighting; make the resulting latent image on it visible by fuming it with mercury vapor; remove its sensitivity to light by liquid chemical treatment, rinse and dry it, then seal the easily marred result behind glass in a protective enclosure.

Henry Fox Talbot publicly introduces the paper-based process he worked out in 1835, calling it "photogenic drawing", but it requires much longer exposures than the daguerreotype and the results are not as clear and detailed.

John Herschel introduces hyposulfite of soda (now known as sodium thiosulfate but still nicknamed "hypo") as a highly effective fixer for all silver-based processes. He also makes the first glass negative.

Sarah Anne Bright creates a series of photograms, six of which are known to still exist. These are the earliest surviving photographic images created by a woman.

Although a bicycle consisting of a frame and wheels has existed for years, blacksmith Kirkpatrick MacMillan (1813-1878), introduces the first bicycle in its modern form, with brakes and pedals. The bike has iron tires and weighs nearly 60 pounds.

Inventor Erastus Brigham Bigelow (1814-1879) introduces the power loom in Massachusetts.

The first electric clock is built by physicist Carl August Steinheil (1801-1870).