Between 1800 and 1803, naturalist Alexander von Humboldt visits Mexico and writes influential accounts of his observations.

Karl Friedrich Burdach coins the term BIOLOGY to denote the study of human morphology, physiology and psychology.

Erasmus Darwin publishes Phytologia declaring that leaves breathe air through tiny pores, sugar and starch are the products of plant "digestion," and nitrates and phosphorus promote vegetation.

Alessandro Volta announces his invention, made in 1799, of the electric battery, also known as the Voltaic pile. It consists of a stack of alternating zinc and silver discs separated by felt soaked in brine. It is the first source of a steady electric current.

William Herschel's "An investigation of the powers of prismatic colors to heat and illuminate objects" tells of his discovery of infrared radiation. While investigating the power of different parts of the spectrum to heat a thermometer, he finds that invisible light beyond the red produces the most heat.

Giuseppe Piazzi discovers first asteroid, which is later named Ceres.

Jean-Baptiste Lamarck's Système de Animaux sans Vertèbres (System for Animals without Vertebrae) includes a classification system for invertebrates and a preliminary view of his ideas of evolution.

The English scientist Thomas Young demonstrates, in his famous double-slit experiment, the interference of light and concludes that light is a wave, not a particle as Sir Isaac Newton had ruled.

In Natural Theology, William Paley uses the analogy of a watch requiring a watchmaker to argue that the universe implies an intelligent designer.

Gottfried Treviranus and Jean Baptiste de Lamarck independently broaden the meaning of BIOLOGY to include the study of all living things.

Considered the father of modern scientific education in America, Benjamin Silliman, Sr., teaches the first modern science course (chemistry at Yale) in the United States. Silliman later becomes a founder in 1818 of the American Journal of Science, one of the oldest scientific journals in the world.

Thomas Young's On the theory of light and colors is the first of three pivotal papers describing his wave theory of light.

(no entry for this year)

Georges Cuvier suggests that fossils found in the area around Paris are "thousands of centuries" old. This casual observation pushes the age of the Earth well beyond its commonly accepted limits. Cuvier also publishes a paper explaining that the fossil animals he has studied bear no resemblance to anything still living, an unambiguous endorsement of the theory of extinction.

James Parkinson publishes the first of a three-volume work entitled Organic Remains of a Former World. In this volume, he describes fossils as the remains of Noah's Flood. In the next several years, he will recognize fossils as the remains of a world before people, and acknowledge as much in the third volume, published in 1811.

Nicolas-Théodore de Saussure's Recherches chimiques sur la végétation "Chemical researches on vegetation" shows that plants require carbon dioxide from the air and nitrogen from the soil. Earlier researchers had assumed the plants got carbon from the soil instead of from the air.

John Leslie's An experimental inquiry into the nature and propagation of heat establishes that the transmission of heat through radiation has the same properties as the propagation of light.

The field of comparative anatomy begins, with the publications of Baron Georges Cuvier's Lesson in Comparative Anatomy

Pierre-Simon Laplace measures molecular forces in liquids and announces his theory of capillary forces.

The English chemist John Dalton develops his atomic theory, proposing that each chemical element is composed of atoms of a single unique type, and that, though they are both immutable and indestructible, they can combine to form more complex structures.

(no entry for this year)

Thomas Young introduces the concept of, and is the first to use the word, ENERGY.

Étienne-Louis Malus discovers that reflected light is polarized and introduces the term POLARIZATION.

12 Feb 1809

Charles Darwin is born

Jean Baptiste de Lamarck's theory of evolution presented with the publication of his Philosophie Zoologique, which emphasized the fundamental unity of life and the capacity of species to vary.