Samuel Haughton (December 21, 1821 – October 31, 1897) was an Irish scientific writer.
He was born in Carlow, the son of James Haughton (1795–1873). His father, the son of a Quaker, but himself a Unitarian, was an active philanthropist, a strong supporter of Father Theobald Mathew, a vegetarian, and an anti-slavery worker and writer.
After a distinguished career in Trinity College, Dublin, Samuel was elected a fellow in 1844. Working on mathematical models under James MacCullagh, he was awarded in 1848 the Cunningham Medal by the Royal Irish Academy.  He was ordained priest in 1847, but seldom preached. In 1851 he was appointed professor of geology in Trinity College, and this post he held for thirty years. He began the study of medicine in 1859, and in 1862 earned the degree of MD from the University of Dublin. He was then made registrar of the Medical School, the status of which he did much to improve, and he represented the university on the General Medical Council from 1878 to 1896. He was elected fellow of the Royal Society in 1858, and in course of time Oxford conferred upon him the hon. degree of DCL, and Cambridge and Edinburgh that of LL.D.
In 1866, Haughton developed the original equations for hanging as a humane method of execution, whereby the neck was broken at the time of the drop, so that the condemned person did not slowly strangle to death. “On hanging considered from a Mechanical and Physiological point of view.” was published in the London, Edinburgh and Dublin Philosophical Magazine and Journal of Science, Vol. 32 No. 213 (July 1866). His system became known as the "Standard Drop" method.
He was a man of remarkable knowledge and ability, and he communicated papers on widely different subjects to various learned societies and scientific journals in London and Dublin. He wrote on the laws of equilibrium, and on the motion of solid and fluid bodies (1846), on sun-heat, terrestrial radiation, geological climates and on tides. He wrote also on the granites of Leinster and Donegal and on the cleavage and joint-planes in the Old Red Sandstone of Waterford (1857-1858). He was president of the Royal Irish Academy from 1886 to 1891, and for twenty years he was secretary of the Royal Zoological Society of Ireland. He delivered the 1880 Croonian Lecture on animal mechanics to the Royal Society.
Samuel Haughton was also involved in the Dublin and Kingstown Railway company, in which he looked after the building of the first locomotives. It was the first railway company in the world to build its own locomotives.
Criticism of Darwin
"Haughton has the dubious honour of being the first person to comment on Darwin’s theory when the joint papers of Darwin and Alfred Russel Wallace were read to the Linnaean Society of London in 1858. They were presented by Darwin’s close allies, the geologist Charles Lyell and the botanist Joseph Dalton Hooker. Haughton presumably saw the printed version of the papers and attacked the theory briefly in remarks made to the Geological Society of Dublin on 9 February 1859. These were reported in the society’s journal, and a clipping of this found its way into Darwin’s possession. Haughton wrote:
This speculation of Mess. Darwin and Wallace would not be worthy of note were it not for the weight of authority of the names under whose auspices it has been brought forward. If it means what it says, it is a truism; if it means anything more, it is contrary to fact.
Darwin later commented in his autobiography that this was the only response to the papers, summarising Haughton’s verdict as ‘all that [was] new in there was false, and what was true was old’."
- Manual of Geology (1865)
- Principles of Animal Mechanics (1873)
- Six Lectures on Physical Geography (1880)
In conjunction with his friend, Professor J Galbraith, he issued a series of Manuals of Mathematical and Physical Science.
- Physicists of Ireland: Passion and Precision. p. 107.
- "Library and Archicve Catalogue". Royal Society. Retrieved 2012-03-09.
- Quakers history, Monkstown Quakers and the Railways
- Charles Darwin and his Dublin critics: Samuel Haughton and William Henry Harvey, by Peter J. Bowler 
- "Author Query for 'Haught.'". International Plant Names Index.
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Haughton, Samuel". Encyclopædia Britannica (11th ed.). Cambridge University Press.