|Born||17 September 1677
|Died||4 January 1761 (aged 83)
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 invented several devices, including a ventilator, a pneumatic trough and a surgical forceps for the removal of bladder stones. He was also a philanthropist and wrote a popular tract on alcoholic intemperance.
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. 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.
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 took 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. His interest in biology, botany and physiology is presumed to date from that time. 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. 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. 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; 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 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. He was one of the eight Foreign Members of the Royal Academy of Sciences, Paris and was elected a member of the Academy of Sciences of Bologna. He received the Copley Medal in 1739 and also became a public figure as a result of his campaigns against the Gin trade and his involvement in the Georgia Trust. He was made a Doctor of Divinity by Oxford University in 1733. 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 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. 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 favourite topic – "The Wisdom and Goodness of God in the formation of Man". Hales died in his 84th year at Teddington on 4 January 1761 after a short illness. 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.
Hales is best known for his Statical Essays. The first volume, Vegetable Staticks (1727), contains an account of experiments in plant physiology and chemistry. The second volume, Haemastaticks (1733), describes experiments on animal physiology including the measurement of the "force of the blood", i.e. blood pressure.
Plant physiology and the chemistry of air
In Vegetable Staticks, Hales studied transpiration – the loss of water from the leaves of plants. He estimated the surface area of the leaves of the plant and the length and surface area of the roots. This allowed Hales to compare the calculated influx of water into the plant with the amount of water leaving the plant by transpiration through the leaves. He also measured 'the force of the sap' or root pressure. Hales commented that "plants very probably draw through their leaves some part of their nourishment from the air". He also speculated that plants might use light as a source of energy for growth, based on Isaac Newton’s suggestion that "gross bodies and light" might be interconvertible. 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 contemporary standards, its importance was acknowledged by Lavoisier, and Hales’ invention of the pneumatic trough to collect gases over water was a major technical advance. Modified forms of the pneumatic trough were later used by William Brownrigg, Henry Cavendish and Joseph Priestley.
Hales began his work on animal physiology with William Stuckeley while in Cambridge, 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. 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. 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 and attributed the resistance to blood flow to friction due to the passage of blood through small blood vessels. 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. 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.
Inventions and other work
Bad or stale air 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 Mårten Triewald and Samuel Sutton) who developed forms of ventilators to improve air quality. Hales’ ventilators were large bellows, usually worked by hand, although larger versions were powered by windmills. They were widely installed in ships, prisons and mines and were successful in reducing disease; versions of Hales' ventilators were also used in preserving foods and drying grain. 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.
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'. 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. In 1732 King George II granted a Charter for the foundation of the colony of Georgia and Hales was one of the twenty one members of the Board of Trustees. The colony of Georgia was notable for its prohibition of slavery and rum. As a result of his involvement with the Board of Trustees of Georgia, Hales learnt of the problems resulting from overcrowding of ships and this spurred him to invent a ship ventilator and undertake experiments to distil fresh water from sea water and to use salt to preserve meat on board ship. 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 of 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 but felt strongly that spirits, and gin in particular, were as he termed it 'The Bane of the Nation'.
"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, 
- Archibald Edmund Clark-Kennedy. Stephen Hales, D.D., F.R.S.: an eighteenth century biography. Cambridge University Press, 1929.
- Schofield, Robert E. (1980). Stephen Hales, Scientist and philanthropist. Menston, Eng: Scolar Press. ISBN 0-85967-482-7.
- G. E. Burget (1925). "Stephen Hales (1677–1761)". Annals of Medical History 7 (2): 9–16.
- Clark-Kennedy, A. E. (1977). "Stephen Hales, DD, FRS". British Medical Journal 2 (6103): 1656–8. doi:10.1136/bmj.2.6103.1656. PMC 1633314. PMID 338121.
- Stephen Hales. Westminster Abbey. Retrieved on 2012-06-15.
- Hall, W. D. (1987). "Stephen Hales: theologian, botanist, physiologist, discoverer of hemodynamics". Clinical Cardiology 10 (8): 487–9. doi:10.1002/clc.4960100816. PMID 3304746.
- Brown S and Simcock DC (2011). "Stephen Hales and the practice of science". Medical Physiology Online.
- Dobbs, J.T. (1982). "Newton's Alchemy and His Theory of Matter". Isis 73 (4): 523. doi:10.1086/353114. quoting Opticks
- West, J. B. (1984). "Stephen Hales: neglected respiratory physiologist". Journal of Applied Physiology 57 (3): 635–9. PMID 6386767.
- Lewis, O. (1994). "Stephen Hales and the measurement of blood pressure". Journal of Human Hypertension 8 (12): 865–71. PMID 7884783.
- Felts, J. H. (1977). "Stephen Hales and the measurement of blood pressure". North Carolina Medical Journal 38 (10): 602–3. PMID 335256.
- Macklem PT (2010). "Stephen Hales, an unrecognized giant of medicine". Osler Library Newsletter (114): 1–4. PMID 21542394.
- Smith IB (1993). "The impact of Stephen Hales on medicine". Journal of the Royal Society of Medicine 86 (6): 349–52. PMC 1294486. PMID 8315630.
- Burchell, Howard B. (1961). "Editorial: Stephen Hales, September 17, 1677 – January 4, 1761". Circulation 23 (1): 1–6. doi:10.1161/01.CIR.23.1.1.
- Geist, D. C. (1972). "An English clergyman and environmental health (Stephen Hales)". Archives of Environmental Health 24 (5): 373–7. PMID 4553667.
- 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. doi:10.1098/rsnr.1978.0012. PMID 11610330.
- Richard I. Shelling (1939). "Benjamin Franklin and the Dr. Bray Associates". The Pennsylvania Magazine of History and Biography 63: 282–293. JSTOR 20087193.
- Werner Forssmann. Biography. nobelprize.org
- Awards and Funding – Awards – American Society of Plant Biologists. My.aspb.org. Retrieved on 2012-06-15.
|Wikisource has original works written by or about:
- 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. doi:10.1086/350503.
- 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)
- "Hales, Stephen". Dictionary of National Biography. London: Smith, Elder & Co. 1885–1900.
- Chisholm, Hugh, ed. (1911). "Hales, Stephen". Encyclopædia Britannica (11th ed.). Cambridge University Press
|Wikimedia Commons has media related to Stephen Hales.|
- Works by Stephen Hales at Project Gutenberg
- Archival material relating to Stephen Hales listed at the UK National Archives