See also: 1865 in science, other events of 1866, 1867 in science and the list of 'years in science'.
Astronomy Giovanni Schiaparelli realizes that meteor streams occur when the Earth passes through the orbit of a comet that has left debris along its path. William Huggins studied the spectrum of a nova and discovers that it is surrounded by a cloud of hydrogen. Biology Gregor Mendel published his laws of inheritance. Ernst Haeckel challenged the plant/animal division of life, observing that single celled organisms, the protists, do not fit into either category. Frederick Smith first discovers Formica candida in the Bournemouth, England, describing it as Formica gagates. Chemistry Dynamite invented by Alfred Nobel. Augustus von Hofmann proposes the now standard system of hydrocarbon nomenclature. Medicine Max Schultze discovers two sorts of 'receptors' in the retina. Patrick Manson starts a school of tropical medicine in Hong Kong Awards Copley Medal: Julius Plücker Wollaston Medal for Geology: Charles Lyell Births Thomas Hunt Morgan, biologist, Nobellaureate in Physiology or Medicine († 1945) Robert Broom, paleontologist († 1951) Deaths June 20 - Bernhard Riemann, mathematician (born 1826) December 1 - George Everest, surveyor and geographer (born 1790)