Christian Friedrich Nasse formulated Nasse's law: hemophilia occurs only in males and is passed on by unaffected females.

Gideon Mantell discovers, in England, a fossil trunk of a tree resembling that of a tropical palm, evidence of a much warmer climate.

André-Marie Ampère formulates one of the basic laws of electromagnetism, the right-hand rule for the influence of an electric current on the magnet and demonstrates that two wires that are carrying an electric current will attract or repel each other, depending on whether the occurrence are in opposite where the same directions.

Dominique-François Arago discovers the magnetic effect of electricity passing through a copper wire, demonstrating that iron is not necessary for magnetism.

Augustin-Jean Fresnel invents the so-called Fresnel lens, a lens used in lighthouses.

The science of electrodynamics is born with the announcement of Hans Christian Ørsted's discovery of electromagnetism.

(no entry for this year)

Etienne Geoffroy publishes Anatomical Philosophy discussing similarities between skeletal structures — such as bat wings, paws and hands — that support the evolutionary claims of Lamarck. He also argues that arthropods and vertebrates have similar but inverse body plans, an assertion that will ultimately be widely accepted.

Between 1822-1824, Thomas Andrew Knight, John Goss, and Alexander Seton all independently perform crosses with the pea and observe dominance in the immediate progeny, and segregation of various hereditary characters in the next generation. However, they do not study later generations or determine the numerical ratios in which the characters are transmitted.

William Buckland publishes an account of how ancient hyenas lived and fed in Kirkdale Cave, based on their fossil remains. This is one of the first descriptions of living habits based on fossil evidence.

Omalius d'Halloy names the Cretaceous System, after massive chalk deposits. This time period will later be identified with the last dinosaurs and the first flowering plants.

William Conybeare and William Phillips name the Carboniferous System, a period associated with coal deposits. This time period will also become known as the Mississippian and Pennsylvanian Periods in the United States.

Thomas Andrew Knight confirms reports of dominance, recessivity, and segregation in peas, but does not detect regularities.

William Buckland finds a skeleton covered in ocher. Called the Red Lady, it will later be identified as Cro-Magnon (and male).

William Buckland publishes Notice on the Megalosaurus ("giant lizard"), the first dinosaur fossil to be described and named, although the term "dinosaur" doesn't yet exist. Buckland also announces the discovery of the first fossil mammal from the Mesozoic.

Réflexions sur la puissance motrice du feu (On the motive power of fire) by Nicolas Léonard Sadi Carnot shows that work is done as heat passes from a high temperature to a low temperature; defines work; hints at the second law of thermodynamics; and suggests internal combustion engines.

Father John MacEnery starts digging in Kent's Cave in Devon. He'll eventually find human remains in the same layer as those of extinct mammals, a finding that will be dismissed by Buckland.

Gideon Mantell publishes Notice on the Iguanodon, the second description of a dinosaur and the first description of an herbivorous fossil reptile.

(no entry for this year)

Karl Ernst von Baer first demonstrated the mammalian ovum; he regarded the sperm cells as "Entozoa," i.e., parasites, and named them spermatozoa.

Theory of systems of rays by William Rowan Hamilton is a unification of the study of optics through the principle of "varying action". It contains his correct prediction of conical refraction. When his prediction is verified, he becomes a well-known and is knighted.

While studying the behavior of fluids under a microscope, botanist Robert Brown (1773-1858) discovers what is today called "Brownian motion".

A year after discovering the mammalian egg cell, Karl Ernst von Baer publishes Entwickelungsgeschichte der Thiere tracing the developmental history of animals.

Publication of Karl Ernst von Baer's The Embryology of Animals which strongly opposed preformationism.

Adolphe Brongniart publishes Prodrome d'une histoire des Végétaux Fossils, a study of fossil plants. He outlines four distinct phases in plant prehistory: (1) primitive plants from the Coal Measures, (2) the first conifers, (3) domination by cycads and conifers, and (4) flowering plants.

Mary Anning discovers Britain's first recognized pterosaur fossil. (Gideon Mantell has already found pterosaur remains, but has attributed them to a bird).

Chemist Friedrich Wöhler (1800-1882) synthesizes the organic compound urea, a feat previously thought impossible because of the vital force thought to be a part of organic substances.

Philippe-Charles Schmerling discovers a Neanderthal fossil, the partial cranium of a small child. The fossil will not be accurately identified as Neanderthal, however, for a century, though Charles Lyell will illustrate it in Antiquity of Man in 1863.

Jules Desnoyers names the Quaternary System, a time in which humans have lived.

Gustave-Gaspard Coriolis coins the term KINETIC ENERGY in On the calculation of mechanical action.

Joseph Henry shows that passing an electric current through a wire wrapped into coils produces a greater magnetic field than is produced when that same current is passed through a straight wire, and that an insulated wire wrapped around an iron core can produce a powerful electromagnet.