Augustus Matthiessen, FRS (2 January 1831, London – 6 October 1870, London), the son of a merchant, is a British chemist and physicist who obtains his PhD in Germany at the University of Gießen in 1852 with Johann Heinrich Buff.
He then works with Robert Bunsen at the University of Heidelberg from 1853 to 1856.
His work in this period includes the isolation of calcium and strontium in their pure states.
He then returns to London and studies with August Wilhelm von Hofmann from 1857 at the Royal College of Chemistry, and sets up his own research laboratory at 1 Torrington Place, Russell Square, London.
He is elected a Fellow of the Royal Society (FRS) in 1861.
He works as a lecturer on chemistry at St Mary's Hospital, London, from 1862 to 1868, and then at St. Bartholomew's Hospital, London, from 1868.
His research is chiefly on the constitution of alloys and opium alkaloids.
He contributes to both physics and chemistry.
For his work on metals and alloys, he is awarded the Royal Society's Royal Medal in 1869.
Matthiessen commits suicide in 1870 under "severe nervous strain".