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Stephen Hales

Stephen Hales
Stephen Hales, aged 82, by J.McArdell after T. Hudson
Born 17 September 1677 (1677-09-17)
Bekesbourne, Kent
Died Did not recognize date. Try slightly modifying the date in the first parameter. (aged 83)
Nationality English
Fields Plant physiology
Notable awards Copley Medal (1739)

Stephen Hales, FRS, DD (17 September 1677 – 4 January 1761) was an English clergyman who made major contributions to a range of scientific fields including botany, pneumatic chemistry and physiology. He was the first person to measure blood pressure. He also invented several devices, including a ventilator, a pneumatic trough and a surgical forceps for the removal of bladder stones. In addition to these achievements was a philanthropist and wrote a popular tract on alcoholic intemperance.


  • Life 1
  • Work 2
    • Plant physiology and the chemistry of air 2.1
    • Animal physiology 2.2
    • Inventions and other work 2.3
    • Philanthropy 2.4
  • Testimony 3
  • See also 4
  • References 5
  • Further reading 6
  • External links 7


Stephen Hales was born in 1677 in Bekesbourne, Kent, England. He was the sixth son of Thomas Hales, heir to Baronetcy of Beakesbourne and Brymore, and his wife, Mary (née Marsham), and was one of twelve or possibly thirteen children.[1][2] Thomas Hales predeceased his father, Sir Robert Hales, and his first son Sir Thomas Hales, 2nd Baronet (Stephen Hales' brother) therefore succeeded to the baronetcy in December 1693.[2]

Hales was educated in Kensington and then at Orpington before attending Corpus Christi College, Cambridge (or St Benedict's as it was then known) in 1696. Although he was an ordinand studying divinity, Hales would have received tuition in the Classics, mathematics, natural sciences and philosophy while in Cambridge. Hales was admitted as a Fellow of Corpus Christi in 1703, the same year as he obtained the degree of Master of Arts, and was ordained as Deacon at Bugden, Cambridgeshire. He continued his theological and other studies in Cambridge, where he became friends with William Stukeley who was studying medicine. He attended chemistry lectures by Giovanni Francisco Vigani while at Cambridge.[3] His interest in biology, botany and physiology is presumed to date from that time.[2]

St Marys Church, Teddington

In 1709 he was ordained Priest at Fulham and on 10 August 1709 he was appointed Perpetual curate of the parish of Teddington, Middlesex and left Cambridge, although he retained his Fellowship until 1718. He became a Bachelor of Divinity in 1711.[4] Hales remained in Teddington for the rest of his life, except for occasional visits to his other parishes. He was an assiduous minister – in addition to parish duties he enlarged and repaired the church and commissioned a new water supply for the village – and well regarded although there is some evidence that his experimental work on animal physiology was viewed with misgivings.[1]Thomas Twining included a verse in his poem The Boat on Hales:

Green Teddington's serene retreat
For Philosophic studies meet,
Where the good Pastor Stephen Hales
Weighed moisture in a pair of scales,
To lingering death put Mares and Dogs,
And stripped the Skins from living Frogs,
Nature, he loved, her Works intent
To search or sometimes to torment.

In 1718, the poet Alexander Pope, a renowned dog lover, also criticized Hales' work. In conversation with his friend, Joseph Spence, Pope reportedly said of Hale: "He commits most of these barbarities with the thought of its being of use to man. But how do we know that we have a right to kill creatures that we are so little above as dogs, for our curiosity, or even for some use to us?".[5] Pope, however was also a close friend of Hales[6] and considered him the model of the man who loves his God.[7]

In 1718 Hales was elected a Fellow of the Royal Society and in the same year became Rector of Porlock, Somerset, a post he held alongside the curacy of Teddington. In 1720 he married Mary Newce, but she died the following year probably in childbirth;[8] there were no children and he never remarried. In 1723 he was installed as Rector of Farringdon, Hampshire (which he held alongside Teddington by employing a curate in Farringdon). Hales spent his summers there and became a friend of Gilbert White, the naturalist, whose family lived there.

Hales' fame as a scientist grew increasingly from 1718 onwards, and by the mid part of the 18th century he had achieved an international reputation.[1] He was one of the eight Foreign Members of the

External links

  •  "Hales, Stephen".  
  • Hales, Stephen (1727) Vegetable Staticks, London: W. and J. Innys — from the Missouri Botanical Garden's library
  • Hales, Stephen (1738). "Philosophical experiments: containing useful, and necessary instructions for such as undertake long voyages at sea. Shewing how sea-water may be made fresh and wholsome: and how fresh water may be preserv'd sweet. How biscuit, corn, &c. may be secured from the weevel, meggots, and other insects. And flesh preserv'd in hot climates, by salting animals whole. To which is added, an account of several experiments and observations on chalybeate or steel-waters ... which were read before the Royal-society, at several of their meetings", London: W. Innys and R. Manby
  • Parascandola, John; Ihde, Aaron J. (1969). "History of the Pneumatic Trough". Isis 60 (3): 351–361.  
  • Stephen Hales at the Galileo Project — details on Hales's life and work
  • For a calendar of manuscript correspondence and writing of Stephen Hales see: D.G.C. Allan and R.E. Schofield, Stephen Hales. Scientist and philanthropist (London: Scolar Press, 1980), p. 178, and for his published writing see ibid p. 191
  • For Hales’s work as parish priest of Teddington see: David G.C. Allan, Science, Philanthropy and Religion in 18th century Teddington: Stephen Hales DD, FRS, (1677–1761) (Twickenham: Borough of Twickenham Local History Society, 2004). This work contains reconstructions of the enlargement of St Mary’s Church, Hale’s copyhold parsonage house and a map of his drainage scheme (Map by Ken Howe).
  • For a general assessment see: David G.C. Allan, Hales, Stephen (1677–1761) in Oxford Dictionary of National Biography.
  • For the 2009 celebration of his life and work see The William Shipley Group for RSA History Newsletter no. 22 (Nov 2009)
  • For Hales’s association with the Society of Arts see David G.C. Allan, ‘Founder of the Society of Arts’ group article in Oxford Dictionary of National Biography (online supplement, 2008)

Further reading

  1. ^ a b c d e f g h i j k Archibald Edmund Clark-Kennedy. Stephen Hales, D.D., F.R.S.: an eighteenth century biography. Cambridge University Press, 1929.
  2. ^ a b c d e f g h Schofield, Robert E. (1980). Stephen Hales, Scientist and philanthropist. Menston, Eng: Scolar Press.  
  3. ^ Dawson, P. M. The Biography of Stephen Hales, D.D., F.R.S. The Johns Hopkins Hospital Bulletin, 1904; 15 (159): 1-19.
  4. ^ G. E. Burget (1925). "Stephen Hales (1677–1761)" (PDF). Annals of Medical History 7 (2): 9–16. 
  5. ^ Joseph Spence, Observations, anecdotes, and characters of books and men collected from conversation, ed. James M. Osborn (Oxford, 1966), vol. 1, p. 118.
  6. ^ Rom Harré (2002). Great Scientific Experiments: Twenty Experiments that Changed Our View of the World. Courier Corporation. pp. 58–.  
  7. ^ In the Epistle to a Lady, 1. 198: Works of Pope (Twickenham edn.) iii (2)
  8. ^ a b Clark-Kennedy, A. E. (1977). "Stephen Hales, DD, FRS". British Medical Journal 2 (6103): 1656–8.  
  9. ^ Stephen Hales. Westminster Abbey. Retrieved on 15 June 2012.
  10. ^ Online: Statique des végétaux.
  11. ^ Hall, W. D. (1987). "Stephen Hales: theologian, botanist, physiologist, discoverer of hemodynamics". Clinical Cardiology 10 (8): 487–9.  
  12. ^ a b c Brown S and Simcock DC (2011). "Stephen Hales and the practice of science". Medical Physiology Online. 
  13. ^ Floto F. Stephen Hales and the cohesion theory. Trends Plant Sci. 1999;4(6):209.
  14. ^ Dobbs, J.T. (1982). "Newton's Alchemy and His Theory of Matter". Isis 73 (4): 523.   quoting Opticks
  15. ^ West, J. B. (1984). "Stephen Hales: neglected respiratory physiologist". Journal of Applied Physiology 57 (3): 635–9.  
  16. ^ Lewis, O. (1994). "Stephen Hales and the measurement of blood pressure". Journal of Human Hypertension 8 (12): 865–71.  
  17. ^ Felts, J. H. (1977). "Stephen Hales and the measurement of blood pressure". North Carolina Medical Journal 38 (10): 602–3.  
  18. ^ a b Macklem PT (2010). "Stephen Hales, an unrecognized giant of medicine". Osler Library Newsletter (114): 1–4.  
  19. ^
  20. ^ Smith IB (1993). "The impact of Stephen Hales on medicine". Journal of the Royal Society of Medicine 86 (6): 349–52.  
  21. ^ Burchell, Howard B. (1961). "Editorial: Stephen Hales, September 17, 1677 – January 4, 1761". Circulation 23 (1): 1–6.  
  22. ^ Geist, D. C. (1972). "An English clergyman and environmental health (Stephen Hales)". Archives of Environmental Health 24 (5): 373–7.  
  23. ^ Boss, J M (1978). "A collection of some observations on bills of mortality & parish registers: an unpublished manuscript by Stephen Hales, F.R.S. (1677–1761)". Notes and records of the Royal Society of London 32 (2): 131–47.  
  24. ^ Richard I. Shelling (1939). "Benjamin Franklin and the Dr. Bray Associates". The Pennsylvania Magazine of History and Biography 63: 282–293.  
  25. ^ Werner Forssmann. Biography.
  26. ^ Raymond Phineas Stearns (1970). Science in the British Colonies of America. University of Illinois Press. pp. 732–.  
  27. ^ Awards and Funding – Awards – American Society of Plant Biologists. Retrieved on 15 June 2012.


See also

The genus of trees Halesia was named after him by John Ellis in 1759.[26] The American Society of Plant Biologists awards the Stephen Hales Prize[27] annually to a scientist for work in plant biology.

"The credit for carrying out the first catheterization of the heart of a living animal for a definite experimental purpose is due to an English parson, the Reverend Stephen Hales. This scientifically interested layman undertook in Tordington (sic) in 1710, 53 years after the death of William Harvey (1578–1657), the first precise definition of the capacity of a heart. He bled a sheep to death and then led a gun-barrel from the neck vessels into the still-beating heart. Through this, he filled the hollow chambers with molten wax and then measured from the resultant cast the volume of the heartbeat and the minute-volume of the heart, which he calculated from the pulse-beat. Besides this, Stephen Hales was also the first, in 1727, to determine arterial blood pressure, when he measured the rise in a column of blood in a glass tube bound into an artery."
— Werner Forssmann, [25]

From the Nobel Prize in Medicine acceptance speech given by Werner Forssmann in 1956:

Halesia Carolina


Hales was one of the co-founders of the Royal Society of Arts conceived by William Shipley. Hales was also active in the movement to promote the Gin Act 1736. He wrote a number of anonymous tracts against the consumption of gin and distilled spirits, most notably 'A Friendly Admonition to the Drinker of Brandy and other Distilled Spirituous Liquors'. and also lobbied Parliament. Hales was not opposed to all alcoholic beverages[2] but felt strongly that spirits, and gin in particular, were as he termed it 'The Bane of the Nation'.[1]

As a result of his involvement with the distil fresh water from sea water and to use salt to preserve meat on board ship.

The colony of Georgia was notable for its prohibition of slavery and rum. [1] In 1732

After the death of his wife, Hales became increasingly involved in philanthropic causes. In 1722 he became a corresponding member of the Society for Promoting Christian Knowledge, founded by Thomas Bray. In 1723 Bray became ill and appointed trustees, including Hales, to administer a bequest from Abel Tassin, Sieur d’Allone for 'The Conversion of Negroes Slaves in the West Indies'.[1][24] Subsequently, Hales was also appointed a trustee for Bray’s legacy for establishing parochial libraries in the American colonies. These charities became incorporated into a scheme led by James Oglethorpe to establish a charitable colony for the poor, 'honest industrious debtors' and persecuted (Protestant) foreigners. Hales may well have felt a personal commitment to this scheme since his brothers had been imprisoned for debt following the failure of the South Sea Company and one, William, died of Gaol Fever in Newgate Prison.[2]

Stephen Hales standing on the extreme left, behind chair, and the Trustees of the colony of Georgia receiving the Indians


Hales also experimented with ways of distilling fresh water from sea water; preserving water and meat on sea-voyages; measuring depths at sea; measuring high temperatures; and wrote on a range of subjects including earthquakes; methods of preventing the spread of fires; and comparative mortality rates in relationship to rural and urban parishes.[22][23]

was thought to be a cause of ill-health and death in the 18th century. Death and disease were common in overcrowded ships and prisons. Hales was one of several people in the early 18th century (other notable inventors being John Theophilus Desaguliers, Mårten Triewald and Samuel Sutton) who developed forms of ventilators to improve air quality.[1] Hales’ ventilators were large bellows, usually worked by hand, although larger versions were powered by windmills.[2] They were widely installed in ships, prisons and mines and were successful in reducing disease;[1] versions of Hales' ventilators were also used in preserving foods and drying grain.

Bad air
Image of a Ventilation Bellows devised by Stephen Hales

Inventions and other work

Hales' work on the growth pattern of long bones, demonstrating epiphyseal growth; his demonstration of spinal reflexes in the frog and his suggestion that electricity played a role in allowing nerves to control muscle function are also noteworthy.[21]

Hales also described a diverse range of work in Haemastaticks including his attempts to find substances that could be used to dissolve bladder stones or calculi. This aim was unsuccessful but as part of this work he developed a double lumen bladder catheter and devised special forceps to enable the removal of urinary stones.[20]

Hales began his work on animal physiology with William Stuckeley while in Cambridge,[8] although much of it was published only after Vegetable Staticks appeared. Hales and Stuckeley performed a wide range of studies including making casts of the trachea and bronchial trees of dogs using molten lead and measuring the water lost due to breathing.[15] Most famously, Hales made measurements of blood pressure in several animal species by inserting fine tubes into arteries and measuring the height to which the column of blood rose.[16][17] Hales also described the effects of hemorrhage and hemorrhagic shock by progressive exsanguination of animals and accompanying measurement of blood pressure.[18] In a horse he observed that as death approached “the Mare fell into cold and clammy sweats.” In addition, Hales took wax casts of the ventricle of the heart and estimated how much blood was pumped by the heart; correctly described the roles of the mitral valve and aortic valve during systole and diastole; explained the pulsations of arteries in terms of their elasticity[19] and attributed the resistance to blood flow to friction due to the passage of blood through small blood vessels.[18]

Animal physiology

In Vegetable Staticks Hales also described experiments that showed that "… air freely enters plants, not only with the principal fund of nourishment by the roots, but also thro’ the surface of their trunks and leaves". While Hales’ work on the chemistry of air appears primitive by modern standards, its importance was acknowledged by [12]

In Vegetable Staticks, Hales studied [12] Hales commented that "plants very probably draw through their leaves some part of their nourishment from the air". In Vegetable Staticks Hales prefigured the cohesion theory of water movement in plants, although his ideas were not understood at the time, so he did not influence the debate on water transport in plants in the 19th century.[13] He also speculated that plants might use light as a source of energy for growth (i.e. photosynthesis), based on Isaac Newton’s suggestion that "gross bodies and light" might be interconvertible.[14]

From Vegetable Staticks, opposite page 262

Plant physiology and the chemistry of air

Hales is best known for his Statical Essays. The first volume, Vegetable Staticks (1727), contains an account of experiments in Buffon in 1735.[10] The second volume, Haemastaticks (1733), describes experiments on animal physiology including the measurement of the "force of the blood", i.e. blood pressure.[11]


At the age of seventy Hales was chosen by the President and Fellows of the Royal College of Physicians to preach the annual Crounian Sermon in the church of St Mary-le-Bow. He selected his favorite topic – "The Wisdom and Goodness of God in the formation of Man".[1] Hales died in his 84th year at Teddington on 4 January 1761 after a short illness.[1] At his own request he was buried under the tower of the church where he had worked for so many years. A monument to Hales was raised by Princess Augusta in the south transept of Westminster Abbey after his death.[9]

In his later years he received frequent visits from Frederick, Prince of Wales and his wife, Princess Augusta of Saxe-Gotha, both of whom were interested in gardening and botany. He gave Princess Augusta advice on the development of Kew Gardens[2] and in 1751 he was appointed Clerk of the Closet to the Princess Dowager, following the death of Prince Frederick, a post he held until his death.

in 1733. Oxford University by Doctor of Divinity He was made a [2][1]

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