JOHN DALTON, D.C.L., L.L.D., F.R.S., L. and E.
MEMBER OF THE INSTITUTE OF FRANCE.
Born September 5, 1766. Died July 27, 1844.
John Dalton was born at Eaglesfield, a small village in Cumberland, near Cockermouth. His father, Joseph Dalton, was a woollen-weaver, and at the birth of his second son, John, gained but a scanty subsistence by weaving common country goods. At the death of his elder brother, however, he inherited a small estate of sixty acres, which enabled him to give up weaving. John Dalton had consequently few opportunities of obtaining a good education; he was emphatically self-taught, and from his very childhood began to acquire those habits of stern self-reliance and indomitable perseverance which in after life, rather than any direct inspirations of genius (as Dalton himself used to affirm), enabled him to work out his grand discovery of the 'Atomic Theory.'
Dalton attended the schools in the neighbourhood of Eaglesfield until eleven years old, by which time he had gone through a course of mensuration, surveying, and navigation. At the age of twelve he began to teach in the village school, and for the next two or three years continued to be partially occupied in teaching and in working on his father's farm. When fifteen years old he removed to Kendal, to become an assistant in a boarding school established there; and, after remaining in this capacity for four years, he determined to undertake, with the assistance of his elder brother, the management of the same school. Dalton continued to be connected with this school for the next eight years, during which time he occupied his leisure in studying Greek, Latin, French, and Natural Philosophy, and was also a frequent contributor to the 'Gentleman's and Lady's Diaries,' two periodicals then in considerable repute. While residing at Kendal, Dalton became acquainted with Mr. Gough, a man who, though blind from infancy, was yet possessed of high scientific attainments. With this gentleman he contracted an intimate friendship, and in 1793 was invited, chiefly through Mr. Gough's favourable recommendation, to join a college, established in Manchester by a body of Protestant dissenters, as tutor in the department of mathematics and natural philosophy. He resigned this appointment after holding it for a period of six years, but continued to reside in Manchester during the whole of his subsequent life.
In September 1793 Dalton published his first work, entitled 'Meteorological Observations and Essays,' the materials of which were, however, collected, and the work entirely completed during his residence at Kendal. A second edition was printed in 1834, and he continued to pay much attention to this subject until within a short period of his death, by which time he had recorded upwards of 200,000 meteorological observations.
In the year 1794 Dalton became a member of the Literary and Philosophical Society of Manchester, of which, during the course of his life, he filled in succession all the more important offices; including that of the presidentship, which he held from the period of his election in 1817, until his death in 1844. On the 31st of October, 1794, he read his first paper to this Society, entitled, 'Extraordinary Facts relating to the Vision of Colours,' in which he gives an account of a singular defect in his own vision, known by the name of colour-blindness, which rendered him incapable of distinguishing certain colours, such as scarlet and green. He first became aware of this defect in his sight from the following circumstance. When a boy he had gone to see a review of troops, and being surprised to hear those around him expatiating on the gorgeous effect of the military costume, he asked, "In what a soldier's coat differed from the grass upon which he trod," a speech which was received by his companions with derisive laughs and exclamations of wonder.[16] Until Dalton had announced his own case, and described the cases of more than twenty persons similarly circumstanced, this peculiar form of blindness was supposed to be very rare. In the annals of the above-mentioned Society, Dalton published a long series of important essays, among the most remarkable of which are some papers read in the year 1801, entitled, 'Experimental Essays on the Constitution of Mixed Gases;' 'On the Force of Steam or Vapour and other liquids at different temperatures in a vacuum and in air;' 'On Evaporation,' and 'On the Expansion of Gases by Heat.' In January 1803 he read to the same Society an inquiry 'On the tendency of Elastic fluids to diffusion through each other,' and in October of the same year wrote an Essay containing an outline of his speculations on the subject of the composition of bodies, in which he gave to the world for the first time a 'Table of Atomic Weights.' In the following year he communicated his views on the theory of definite proportions to Dr. Thomas Thomson, of Glasgow, who at once published an abstract of them; and in 1808 Dalton himself published the first volume of his new system of Chemical Philosophy, in which he placed the Atomic Theory on a firm and clear basis, and established the law of Multiple Proportions. The value of Dalton's researches on this great subject is immense; by the promulgation of his views Chemistry became for the first time a science, and one great law or theory was seen to govern its actions; before it was a series of separate facts, but by this fundamental law and its branches, and by this only, it is preserved as a science.
Dalton's theory incurred much opposition before it was finally accepted by scientific men, and among the unbelievers in it may be mentioned Sir Humphry Davy. The baronet, however, in the year 1826, clearly acknowledged and accurately defined Dalton's discoveries in his anniversary discourse, when he made known that the first award of the Royal Society's Prize, founded by George IV. in the year before, would be given to Mr. John Dalton, "for the development of the chemical theory of Definite Proportions, usually called the Atomic Theory, and for his various other labours and discoveries in physical and chemical science."
During his later life Dalton continued to gain his living as professional chemist, lecturer, and teacher of Chemistry and Mathematics, and contributed to the advancement of science many valuable papers chiefly relating to Chemistry; he was also accustomed in his analytical researches to use the graduated dropping tube, and may be considered as the originator of analysis by volume. Mr. Dalton was present at the first meeting of the British Association held in York in 1831, and continued to feel a lively interest in its prosperity, and to attend the annual meetings as long as his health permitted him. On the occasion of the second meeting at Oxford in 1832, the honorary degree of D.C.L. was conferred upon him, in conjunction with Faraday, Brown the botanist, and Sir David Brewster. In the summer of the following year, at the meeting of the same society in Cambridge, it was announced by Professor Sedgewick, that the King had conferred on Dalton a pension of 150l. per annum, which was increased in 1836 to 300l.; and as his brother Jonathan died about the same time and left him heir to the paternal estate, he became comparatively wealthy. He, however, still continued working according to his strength, and so late as 1840 published four Essays, entitled, 'On the Phosphates and Arseniates;' 'Microcosmic Salt;' 'Acids, Bases, and Water;' and 'A New and Easy Method of Analysing Sugar.' In 1837-8 Dalton was attacked by paralysis, which greatly enfeebled him; he, however lived till the year 1844, when a third attack occurred, from which he never recovered, but died shortly afterwards in his seventy-eighth year.