John Dalton (6 September 1766 – 27 July 1844) was an English chemist, meteorologist and physicist. He is best known for his pioneering work in the development of modern atomic theory, and his research into colour blindness (sometimes referred to as Daltonism, in his honour).
- Philosophers are generally persuaded, that the sensations of heat and cold are occasioned by the presence or absence, in degree, of certain principle or quality denominated fire or heat... It is most probable, that all substances whatever contain more or less of this principle. Respecting the nature of the principle, however, there is a diversity of sentiment : some supposing it a substance, others a quality, or property of substance. Boerhaave, followed by most of the moderns, is of the former opinion; Newton, with some others, are of the latter; these conceive heat to consist in an internal vibratory motion of the particles of bodies.
- Meteorological Observations and Essays: Mit Tabellen, 1834 p. 18
- 1. Small particles called atoms exist and compose all matter; 2. They are indivisible and indestructible; 3. Atoms of the same chemical element have the same chemical properties and do not transmute or change into different elements.
Quotes about John Dalton
- From the hour he came from his mother's womb, the God of Nature had laid his hand upon his head, and had ordained him for the ministration of high philosophy. But his natural talents, great as they were, and his almost intuitive skill in tracing the relations of material phaenomena, would have been of comparatively little value to himself and to society, had there not been superadded to them a beautiful moral simplicity and singleness of heart, which made him go on steadily in the way he was before him, without turning to right hand or to the left, and taught him to do homage to no authority before that of truth.
- Reverend Dr. William Buckland, President of the Geological Society of London. Murray, 1834, found in Meeting of the British Association for the Advancement of Science. p. XI.
- The most extraordinary man I met [in Manchester] is John Dalton, whose name is better known in almost any country of Europe than his own, and in any town than in Manchester. He is generally styled by continental writers the Father of Modern Chemistry, and is one of the eight associates of the Institute. Yet this man between sixty and seventy is earning, as I had a peculiar satisfaction in seeing with my own eyes, a penurious existence by teaching boys the elements of mathematics, with which he is so totally occupied, that he can hardly snatch a moment for the prosecution of discoveries which have already put his name on a level with the courtly and courted Davy. But the remarkable thing is that this simple and firm-minded man preserves all the original simplicity and equanimity of his mind, and calmly leaves his fame, like Bacon, to other nations and future ages.'
- James David Forbes, as quoted by John Campbell Ghairp and Peter Guthrie Tait in Life and letters of James David Forbes p. 450.
- Another immense service rendered by Dalton, as a corollary of the new atomic doctrine, was the creation of a system of symbolic notation, which not only made the nature of chemical compounds and processes easily intelligible and easy of recollection, but, by its very form, suggested new lines of inquiry. The atomic notation was as serviceable to chemistry as the binomial nomenclature and the classificatory schematism of Linnæus were to zoölogy and botany.
- The conviction that chemical substances combine according to fixed and simple proportions gained ground on the Continent, chiefly during the discussion in which Proust finally disproved and defeated Berthollet's theory of chemical affinity; but it is to Dalton that the doctrine of fixed and multiple proportions is indebted for a consistent exposition. Dalton based it upon a mental representation which ever since has been the soul of all chemical reasoning.