Editing 1840 in science (section)

==Deaths==
* March 2 – [[Heinrich Wilhelm Matthias Olbers]] (born [[1758 in science|1758]]), German [[astronomer]].
* March 23 – [[William Maclure]] (born [[1763 in science|1763]]), Scottish American [[geologist]].
* April 25 – [[Siméon Denis Poisson]] (born [[1781 in science|1781]]), French [[mathematician]].
* April 29 – [[Pierre Jean Robiquet]] (born [[1780 in science|1780]]), French chemist.
* July 4 – [[Karl Ferdinand von Gräfe]] (born [[1787 in science|1787]]), German [[surgeon]].
* August 31 - [[Giuseppangelo Fonzi]], Italian dentist (born [[1768 in science|1768]])<ref>{{treccani|giuseppangelo-lucinto-fonzi_(Dizionario-Biografico)|Giuseppangelo Lucinto Fonzi|Luciano Bonuzzi|1997}}</ref>
* September 18 – [[Constantine Samuel Rafinesque]] (born [[1783 in science|1783]]), French American [[polymath]].
* November 2 – Sir [[Anthony Carlisle]] (born [[1768 in science|1768]]), English surgeon.
* December 11 – [[Franz Bauer]] (born 1758), Moravian-born botanical illustrator.