See also: 1869 in science, other events of 1870, 1871 in science, and the list of years in science.
Introduced rabbitss reach the New South Wales border in Australia.
Felix Klein constructs an analytic geometry for Lobachevski's geometry theory establishing its self-consistency and the logical independence of Euclid's fifth postulate.
Louis Pasteur and Robert Koch establish the germ theory of disease.
November 1 - In the United States, the newly-created Weather Bureau (later renamed the National Weather Service) makes its first official meteorological forecast: "High winds at Chicago and Milwaukee... and along the Lakes".
Rudolph Clausius proves the scalar virial theorem.
February 26 - In New York City, the first pneumatic-subway is opened.
Collotype black and white photographic process invented.
The Magic Lantern movie projector is invented by Henry R. Heyl.
The stock ticker is invented by Thomas Alva Edison.
First known use of weapons for the anti-aircraft role at Paris during the Franco-Prussian War.
January 15 - Pierre S. DuPont, industrialist
March 17th - Horace Donisthorpe, entomologist, myrmecologist, coleopterist (? 1951)
Charles Xavier Thomas de Colmar, inventor of the first mass-produced calculator.