John DaltonFRS (/ˈdɔːltən/; 5 or 6 September 1766 – 27 July 1844) was an Englishchemist,physicist, andmeteorologist whose work laid the foundations of modernatomic theory andstoichiometric chemistry. Building on earlier ideas about the indivisibility of matter and his own precise measurements of combining ratios, Dalton proposed that each chemical element consists of identical atoms of characteristic weight, and that compounds are formed when atoms of different elements combine in fixed whole-number proportions. HisA New System of Chemical Philosophy (1808) presented a coherent atomic model, supplied relative atomic weights and symbolic notation, and established the quantitative framework that shaped nineteenth-century chemistry and remains the basis of modern chemical thought.
Dalton was also a pioneeringmeteorologist andphysicist, keeping daily weather observations for over fifty years, formulating the first empiricallaw of partial pressures (later known as Dalton’s Law), and studying the behavior of gases through his work onvapor pressure and gas solubility. His investigations into his owncolor blindness led to the first scientific description of the condition—still called Daltonism in several languages—and helped establish experimental methods for linking perception with physiology. Elected aFellow of the Royal Society in 1822 and awarded itsRoyal Medal in 1826, Dalton became the first British scientist to develop a quantitative atomic theory and one of the key figures in the transition of chemistry from a qualitative to a mathematical science.
In honour of Dalton's work, a unit of atomic mass, thedalton, symbol Da, is officially accepted for use with theSI.
Early life
Historical plaque marking birthplace of John DaltonModern plaque marking birthplace of John Dalton
John Dalton was born on 5 or 6 September 1766 into aQuaker family inEaglesfield, nearCockermouth, inCumberland, England.[1][2] His father was a weaver.[3] He received his early education from his father and from Quaker John Fletcher, who ran a private school in the nearby village ofPardshaw Hall. Dalton's family was too poor to support him for long and he began to earn his living, from the age of ten, in the service of wealthy local Quaker Elihu Robinson.[4]
Scientific work
Meteorology
1793 copy of Dalton's first publication, "Meteorological Observations and Essays"
Dalton's early life was influenced by a prominent Quaker, Elihu Robinson,[2] a competentmeteorologist and instrument maker, from Eaglesfield,Cumberland, who interested him in problems of mathematics and meteorology. During his years in Kendal, Dalton contributed solutions to problems and answered questions on various subjects inThe Ladies' Diary and theGentleman's Diary. In 1787 at age 21 he began his meteorological diary in which, during the succeeding 57 years, he entered more than 200,000 observations.[5][6] He rediscoveredGeorge Hadley's theory of atmospheric circulation (now known as theHadley cell) around this time.[7] In 1793 Dalton's first publication,Meteorological Observations and Essays, contained the seeds of several of his later discoveries but despite the originality of his treatment, little attention was paid to them by other scholars. A second work by Dalton,Elements of English Grammar (orA new system of grammatical instruction: for the use of schools and academies), was published in 1801.[8]
Measuring mountains
After leaving theLake District, Dalton returned annually to spend his holidays studying meteorology, something which involved a lot of hill-walking. Until the advent of aeroplanes andweather balloons, the only way to make measurements of temperature and humidity at altitude was to climb a mountain. Dalton estimated the height using abarometer. TheOrdnance Survey did not publish maps for the Lake District until the 1860s. Before then, Dalton was one of the few authorities on the heights of the region's mountains.[9] He was often accompanied byJonathan Otley, who also made a study of the heights of the local peaks, using Dalton's figures as a comparison to check his work. Otley published his information in his map of 1818. Otley became both an assistant and a friend to Dalton.[10]
Colour blindness
In 1794, shortly after his arrival in Manchester, Dalton was elected a member of theManchester Literary and Philosophical Society, the "Lit & Phil", and a few weeks later he communicated his first paper on "Extraordinary facts relating to the vision of colours", in which he postulated that shortage in colour perception was caused by discoloration of the liquid medium of the eyeball. As both he and his brother werecolour blind, he recognised that the condition must be hereditary.[11]
Although Dalton's theory was later disproven, his early research into colour vision deficiency was recognized after his lifetime.[a] Examination of his preserved eyeball in 1995 demonstrated that Dalton haddeuteranopia, a type ofcongenital red-green color blindness in which the gene for medium wavelength sensitive (green)photopsins is missing.[11] Individuals with this form of colour blindness see every colour as mapped to blue, yellow or gray, or, as Dalton wrote in his seminal paper,[13]
That part of the image which others call red, appears to me little more than a shade, or defect of light; after that the orange, yellow and green seem one colour, which descends pretty uniformly from an intense to a rare yellow, making what I should call different shades of yellow.
In 1800, Dalton became secretary of the Manchester Literary and Philosophical Society, and in the following year he presented an important series of lectures, entitled "Experimental Essays" on the constitution of mixed gases; thepressure of steam and othervapours at different temperatures in avacuum and inair; onevaporation; and on thethermal expansion of gases. The four essays, presented between 2 and 30 October 1801, were published in theMemoirs of the Literary and Philosophical Society of Manchester in 1802.
There can scarcely be a doubt entertained respecting the reducibility of all elastic fluids of whatever kind, into liquids; and we ought not to despair of effecting it inlow temperatures and by strong pressures exerted upon the unmixed gases further.
After describing experiments to ascertain the pressure of steam at various points between 0 and 100 °C (32 and 212 °F), Dalton concluded from observations of thevapour pressure of six different liquids, that the variation of vapour pressure for all liquids is equivalent, for the same variation of temperature, reckoning from vapour of any given pressure.
I see no sufficient reason why we may not conclude, that all elastic fluids under the same pressure expand equally by heat—and that for any given expansion ofmercury, the corresponding expansion of air is proportionally something less, the higher the temperature. ... It seems, therefore, that general laws respecting the absolute quantity and the nature of heat, are more likely to be derived from elastic fluids than from other substances.
He enunciatedGay-Lussac's law, published in 1802 byJoseph Louis Gay-Lussac (Gay-Lussac credited the discovery to unpublished work from the 1780s byJacques Charles). In the two or three years following the lectures, Dalton published several papers on similar topics. "On the Absorption of Gases by Water and other Liquids" (read as a lecture on 21 October 1803, first published in 1805)[16] contained his law of partial pressures now known asDalton's law.
Dalton'satomic model as depicted in John Dalton'sA New System of Chemical Philosophy (1808) on page 546, 547 and 589.
Atomic theory
Arguably the most important of all Dalton's investigations are concerned with theatomic theory in chemistry. While his name is inseparably associated with this theory, the origin of Dalton's atomic theory is not fully understood.[17][18] The theory may have been suggested to him either by researches onethylene (olefiant gas) andmethane (carburetted hydrogen) or by analysis ofnitrous oxide (protoxide of azote) andnitrogen dioxide (deutoxide of azote), both views resting on the authority ofThomas Thomson.[19]
From 1814 to 1819, Irish chemistWilliam Higgins claimed that Dalton had plagiarised his ideas, but Higgins' theory did not address relative atomic mass.[20][21] Recent evidence suggests that Dalton's development of thought may have been influenced by the ideas of another Irish chemistBryan Higgins, who was William's uncle. Bryan believed that an atom was a heavy central particle surrounded by an atmosphere ofcaloric, the supposed substance of heat at the time. The size of the atom was determined by the diameter of the caloric atmosphere. Based on the evidence, Dalton was aware of Bryan's theory and adopted very similar ideas and language, but he never acknowledged Bryan's anticipation of his caloric model.[22][23] However, the essential novelty of Dalton's atomic theory is that he provided a method of calculating relative atomic weights for the chemical elements, which provides the means for the assignment of molecular formulas for all chemical substances. Neither Bryan nor William Higgins did this, and Dalton's priority for that crucial innovation is uncontested.[18]
A study of Dalton's laboratory notebooks, discovered in the rooms of the Manchester Literary and Philosophical Society,[24] concluded that Dalton was not led by his search for an explanation of thelaw of multiple proportions to the idea that chemical combination consists in the interaction of atoms of definite and characteristic weight, but rather the idea of atoms arose in his mind as a purely physical concept, forced on him by study of the physical properties of theatmosphere and other gases. The first published indications of this idea are to be found at the end of his paper "On the Absorption of Gases by Water and other Liquids"[16] already mentioned. There he says:
Why does not water admit its bulk of every kind of gas alike? This question I have duly considered, and though I am not able to satisfy myself completely I am nearly persuaded that the circumstance depends on the weight and number of the ultimate particles of the several gases.
He then proposes relative weights for the atoms of a few elements, without going into further detail. However, a recent study of Dalton's laboratory notebook entries concludes he developed the chemical atomic theory in 1803 to reconcileHenry Cavendish's andAntoine Lavoisier's analytical data on the composition of nitric acid, not to explain the solubility of gases in water.[25]
The main points of Dalton's atomic theory, as it eventually developed, are:
Elements are made of extremely small particles calledatoms.
Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.
Atoms cannot be subdivided, created or destroyed.
Atoms of different elements combine in simple whole-number ratios to formchemical compounds.
In his first extended published discussion of the atomic theory (1808), Dalton proposed an additional (and controversial) "rule of greatest simplicity". This rule could not be independently confirmed, but some such assumption was necessary in order to propose formulas for a few simple molecules, upon which the calculation of atomic weights depended. This rule dictated that if the atoms of two different elements were known to form only a single compound, like hydrogen and oxygen forming water or hydrogen and nitrogen forming ammonia, the molecules of that compound shall be assumed to consist of one atom of each element. For elements that combined in multiple ratios, such as the then-known two oxides of carbon or the three oxides of nitrogen, their combinations were assumed to be the simplest ones possible. For example, if two such combinations are known, one must consist of an atom of each element, and the other must consist of one atom of one element and two atoms of the other.[26]
This was merely an assumption, derived from faith in the simplicity of nature. No evidence was then available to scientists to deduce how many atoms of each element combine to form molecules. But this or some other such rule was absolutely necessary to any incipient theory, since one needed an assumed molecular formula in order to calculate relative atomic weights. Dalton's "rule of greatest simplicity" caused him to assume that the formula for water was OH andammonia was NH, quite different from our modern understanding (H2O, NH3). On the other hand, his simplicity rule led him to propose the correct modern formulas for the two oxides of carbon (CO and CO2). Despite the uncertainty at the heart of Dalton's atomic theory, the principles of the theory survived.
Relative atomic weights
Various atoms andmolecules as depicted in John Dalton'sA New System of Chemical Philosophy (1808) on page 238
Dalton published his first table of relativeatomic weights containing six elements (hydrogen, oxygen, nitrogen, carbon, sulfur and phosphorus), relative to the weight of an atom of hydrogen conventionally taken as 1.[16] Since these were only relative weights, they do not have a unit of weight attached to them. Dalton provided no indication in this paper how he had arrived at these numbers, but in his laboratory notebook, dated 6 September 1803,[27] is a list in which he set out the relative weights of the atoms of a number of elements, derived from analysis of water, ammonia,carbon dioxide, etc. by chemists of the time.
The extension of this idea to substances in general necessarily led him to thelaw of multiple proportions, and the comparison with experiment brilliantly confirmed his deduction.[28] In the paper "On the Proportion of the Several Gases in the Atmosphere", read by him in November 1802, the law of multiple proportions appears to be anticipated in the words:
The elements of oxygen may combine with a certain portion of nitrous gas or with twice that portion, but with no intermediate quantity.
But there is reason to suspect that this sentence may have been added some time after the reading of the paper, which was not published until 1805.[29]
Compounds were listed as binary, ternary, quaternary, etc. (molecules composed of two, three, four, etc. atoms) in theNew System of Chemical Philosophy depending on the number of atoms a compound had in its simplest, empirical form.
Dalton hypothesised the structure of compounds can be represented in whole number ratios. So, one atom of element X combining with one atom of element Y is a binary compound. Furthermore, one atom of element X combining with two atoms of element Y or vice versa, is a ternary compound. Many of the first compounds listed in theNew System of Chemical Philosophy correspond to modern views, although many others do not.
Dalton used his own symbols to visually represent the atomic structure of compounds. They were depicted in theNew System of Chemical Philosophy, where he listed 21 elements and 17 simple molecules.
Other investigations
Dalton published papers on such diverse topics as rain and dew and the origin of springs (hydrosphere); on heat, the colour of the sky, steam and thereflection andrefraction of light; and on the grammatical subjects of theauxiliary verbs andparticiples of the English language.
Experimental approach
As an investigator, Dalton was often content with rough andinaccurate instruments, even though better ones were obtainable. SirHumphry Davy described him as "a very coarse experimenter", who "almost always found the results he required, trusting to his head rather than his hands."[30] On the other hand, historians who have replicated some of his crucial experiments have confirmed Dalton's skill and precision.
In the preface to the second part of Volume I of hisNew System, he says he had so often been misled by taking for granted the results of others that he determined to write "as little as possible but what I can attest by my own experience", but this independence he carried so far that it sometimes resembled lack of receptivity. Thus he distrusted, and probably never fully accepted,Gay-Lussac's conclusions as to the combining volumes of gases.
He held unconventional views onchlorine. Even after its elementary character had been settled by Davy, he persisted in using the atomic weights he himself had adopted, even when they had been superseded by the more accurate determinations of other chemists.
He always objected to the chemical notation devised byJöns Jacob Berzelius, although most thought that it was much simpler and more convenient than his own cumbersome system of circular symbols.
Other publications
ForRees's Cyclopædia Dalton contributed articles on Chemistry and Meteorology, but the topics are not known.
He contributed 117Memoirs of the Literary and Philosophical Society of Manchester from 1817 until his death in 1844 while president of that organisation. Of these the earlier are the most important. In one of them, read in 1814, he explains the principles ofvolumetric analysis, in which he was one of the earliest researchers. In 1840 a paper onphosphates andarsenates, often regarded as a weaker work, was refused by theRoyal Society, and he was so incensed that he published it himself. He took the same course soon afterwards with four other papers, two of which ("On the quantity ofacids,bases and salts in different varieties of salts" and "On a new and easy method of analysing sugar") contain his discovery, regarded by him as second in importance only to atomic theory, that certainanhydrates, when dissolved in water, cause no increase in its volume, his inference being that the salt enters into the pores of the water.
Public life
Even before he had propounded the atomic theory, Dalton had attained a considerable scientific reputation. In 1803, he was chosen to give a series of lectures on natural philosophy at theRoyal Institution in London, and he delivered another series of lectures there in 1809–1810. Some witnesses reported that he was deficient in the qualities that make an attractive lecturer, being harsh and indistinct in voice, ineffective in the treatment of his subject, and singularly wanting in the language and power of illustration[citation needed].
In 1810, Sir Humphry Davy asked him to offer himself as a candidate for thefellowship of the Royal Society, but Dalton declined, possibly for financial reasons. In 1822 he was proposed without his knowledge, and on election paid the usual fee.[31] Six years previously he had been made a corresponding member of the FrenchAcadémie des Sciences, and in 1830 he was elected as one of its eight foreign associates in place of Davy.[32] In 1833,Earl Grey's government conferred on him a pension of£150, raised in 1836 to £300 (equivalent to £17,981 and £35,672 in 2023, respectively)[citation needed]. Dalton was elected a Foreign Honorary Member of theAmerican Academy of Arts and Sciences in 1834.[33]
A youngJames Prescott Joule, who later studied and published (1843) on the nature of heat and its relationship to mechanical work, was a pupil of Dalton in his last years[citation needed].
Personal life
Dalton never married and had only a few close friends. As a Quaker, he lived a modest and unassuming personal life.[1]
For the 26 years prior to his death, Dalton lived in a room in the home of the Rev W. Johns, a published botanist, and his wife, in George Street, Manchester. Dalton and Johns died in the same year (1844).[34]
Dalton's daily round of laboratory work andtutoring in Manchester was broken only by annual excursions to theLake District and occasional visits to London. In 1822 he paid a short visit to Paris, where he met many distinguished resident men of science. He attended several of the earlier meetings of theBritish Association atYork,Oxford, Dublin andBristol.
Disability and death
Dalton suffered a minor stroke in 1837, and a second in 1838 left him with a speech impairment, although he remained able to perform experiments. In May 1844 he had another stroke; on 26 July, while his hand was trembling, he recorded his last meteorological observation. On 27 July, in Manchester, Dalton fell from his bed and was found dead by his attendant.
Dalton was accorded a civic funeral with full honours. His body lay in state inManchester Town Hall for four days and more than 40,000 people filed past his coffin. The funeral procession included representatives of the city's major civic, commercial, and scientific bodies.[35][36] He was buried in Manchester inArdwick Cemetery; the cemetery is now a playing field, but pictures of the original grave may be found in published materials.[37][38]
Much of Dalton's written work, collected by the Manchester Literary and Philosophical Society, was damaged duringbombing on 24 December 1940. It promptedIsaac Asimov to say, "John Dalton's records, carefully preserved for a century, were destroyed during the World War II bombing of Manchester. It is not only the living who are killed in war". The damaged papers are in theJohn Rylands Library.
A bust of Dalton, byChantrey, paid for by public subscription[39] was placed in the entrance hall of theRoyal Manchester Institution. Chantrey's large statue of Dalton, erected while Dalton was alive was placed inManchester Town Hall in 1877. He "is probably the only scientist who got a statue in his lifetime".[36]
The Manchester-based Swissphrenologist and sculptorWilliam Bally made a cast of the interior of Dalton's cranium and of acyst therein, having arrived at theManchester Royal Infirmary too late to make a cast of the head and face. A cast of the head was made, by a Mr Politi, whose arrival at the scene preceded that of Bally.[40]
Ablue plaque commemorates the site of his laboratory at 36 George Street in Manchester.[41][42]
TheUniversity of Manchester established two Dalton Chemical Scholarships, two Dalton Mathematical Scholarships, and a Dalton Prize for Natural History. A hall of residence is namedDalton Hall.
The Dalton Medal has been awarded only twelve times by the Manchester Literary and Philosophical Society.
TheDalton crater on the Moon was named after Dalton.
"Daltonism" is a lesser-known synonym of colour-blindness and, in some languages, variations on this have persisted in common usage: for example, 'daltonien' is the French adjectival equivalent of 'colour-blind', and 'daltónico'/'daltonica' is the Spanish and the Italian.
In honour of Dalton's work, many chemists and biochemists use the unit of massdalton (symbol Da), also known as the unified atomic mass unit, equal to 1/12 the mass of a neutral atom ofcarbon-12). The dalton isofficially accepted for use with the SI.
Quaker schools have named buildings after Dalton: for example, a schoolhouse in the primary sector ofAckworth School, is called Dalton.
^Dalton believed that his vitreous humour possessed an abnormal blue tint, causing his anomalous colour perception, and he gave instructions for his eyes to be examined on his death, to test this hypothesis. His wishes were duly carried out, but no blue colouration was found, and Dalton's hypothesis was refuted. The shrivelled remains of one eye have survived to this day, and now belong to the Manchester Literary and Philosophical Society."[12]
References
^ab"John Dalton".Science History Institute. June 2016.Archived from the original on 11 August 2019. Retrieved20 March 2018.
^Thackray, Arnold W. (1966). "The Origin of Dalton's Chemical Atomic Theory: Daltonian Doubts Resolved".Isis.57:35–55.doi:10.1086/350077.S2CID144818988.
^Thomson, Thomas (1810).The Elements of Chemistry. J. & A.Y. Humphreys. p. 480.Archived from the original on 21 December 2022. Retrieved18 October 2020.
^Wheeler, T. S; Partington, J. R. (1960).The life and work of William Higgins, chemist, 1763–1825 including reprints of "A comparative view of the phlogistic and antiphlogistic theories" and "Observations on the atomic theory and electrical phenomena" by William Higgins. Pergamon Press.
^Grossman, M. I. (2010). "William Higgins at the Dublin Society, 1810–20: The loss of a professorship and a claim to the atomic theory".Notes and Records of the Royal Society.64 (4):417–434.doi:10.1098/rsnr.2010.0020.S2CID146292636.
^Grossman, Mark I. (2017). "John Dalton and the origin of the atomic theory: Reassessing the influence of Bryan Higgins".The British Journal for the History of Science.50 (4):657–676.doi:10.1017/S0007087417000851.PMID29065936.S2CID206212671.
^Levere, Trevor (2001).Transforming Matter: A History of Chemistry from Alchemy to the Buckyball. Baltimore, Maryland: The Johns Hopkins University Press. pp. 84–86, 109.ISBN978-0-8018-6610-4.
^Smith, Robert Angus (1856). "Memoir of John Dalton and History of the Atomic Theory up to his time".Memoirs of the Literary and Philosophical Society of Manchester. Second.13: 298.hdl:2027/mdp.39015016080783.
^"Dalton, John".Complete Dictionary of Scientific Biography. Charles Scribner's Sons. 2008.Archived from the original on 9 August 2017. Retrieved8 August 2017.
^Millington, John Price (1906).John Dalton. London: J. M. Dent & Company. pp. 201–208.ISBN978-0-7222-3057-2.Archived from the original on 23 February 2023. Retrieved24 December 2007.{{cite book}}:ISBN / Date incompatibility (help)
^"The Late Dr Dalton".The Manchester Guardian. 3 August 1844. p. 5.
Smyth, A. L. (1998).John Dalton, 1766–1844: A Bibliography of Works by and About Him, With an Annotated List of His Surviving Apparatus and Personal Effects. Manchester Literary and Philosophical Publications.ISBN978-1-85928-438-4.- Original edition published by Manchester University Press in 1966
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