Editing 1840 in science (section)

==Births==
* January 21 &ndash; [[Sophia Jex-Blake]] (died [[1912 in science|1912]]), [[English people|English]] [[physician]].
* February 5
** [[John Boyd Dunlop]] (died [[1921 in science|1921]]), Scottish-born [[inventor]].
** [[Hiram Maxim]] (died [[1916 in science|1916]]), [[United States|American]]-born inventor of the [[machine gun]].
* February 10 – [[Per Teodor Cleve]] (died [[1905 in science|1905]]), Swedish [[chemist]].
* March 28 – [[Emin Pasha]], born Isaak Schnitzer (died [[1892 in science|1892]]), Silesian-born [[List of explorers|explorer]].
* March 31 – [[Benjamin Baker (engineer)|Benjamin Baker]] (died [[1907 in science|1907]]), English [[civil engineer]].
* April 9 – [[Praskovya Uvarova]] (died [[1924 in science|1924]]), Russian archaeologist. 
* April 22 – [[Thomas Clouston (psychiatrist)|Thomas Clouston]] (died [[1915 in science|1915]]), Scottish [[psychiatrist]].
* July 28 – [[Edward Drinker Cope]] (died [[1897 in science|1897]]), [[Americans|American]] [[paleontologist]].
* August 4 – [[Richard von Krafft-Ebing]] (died [[1902 in science|1902]]), German [[sexologist]].
* November 24 – [[John Brashear]] (died [[1920 in science|1920]]), American [[astronomer]].
* November 29 – [[James Crichton-Browne]] (died [[1938 in science|1938]]), Scottish psychiatrist.