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John Dalton
(c. 6 Sep 1766 - 27 Jul 1844)

English chemist, physicist, meteorologist and teacher.

John Dalton


[p.249] In a Cumberland dale, at the township of Eaglefield, not far from Cockermouth, there lived in 1766 a Quaker family in humble circumstances, who shortly afterwards obtained a small copyhold estate, upon which the good man of the house brought up six children, one of them being John Dalton, born in the year just mentioned. The Society of Friends in those days were much more strict in their adherence to the usages of George Fox than their descendants are at present; and it is easy to picture the drab coat and the broad-brimmed hat of the father, and the sober-coloured gown, and the neat cap, and the white kerchief of the mother, with their little ones like a flock, dressed in corresponding attire, when on first days they followed their parents to “meeting.” John Dalton went to school with “Friend Fletcher,” who lived in the place, and had the care of other children connected with the community. The learning communicated might not be of the highest kind, but the boy is said “to have made very considerable progress in knowledge;” and, in proof of this, we learn that at the age of twelve or thirteen, he set up school for himself, and during two winters instructed other youthful [p.250] villagers, devoting his spare time to farm labour in the service of his father. Even then, he manifested a taste for mathematics, and derived assistance in the study from a neighbouring gentleman of the name of Robinson. At fifteen, the lad went to the town of Kendal, still remarkable for the number and respectability of Quaker families, and remained there for eleven years, engaged in both learning and teaching mathematics, in connexion with physical science. Here he formed the acquaintance of a blind gentleman named Gough, an amateur philosopher to whom, with the help of his library and apparatus, young Dalton was laid under great obligation for further progress. “For about eight years,” he says, “during my residence at Kendal, we were intimately acquainted. Mr. Gough was as much gratified in imparting his stores of science as I was in receiving them; my use to him was chiefly in reading, writing, and making calculations and diagrams, and in participating with him in the pleasure resulting from successful investigations; but as Mr. Gough was above receiving any pecuniary recompense, the balance of advantage was greatly in my favour, and I am glad of having this opportunity of acknowledging it.”

Dalton early commenced authorship by contributing to magazines, and by publishing, in 1793, Meteorological Observations and Essays. The same year he removed to Manchester; and in that busy hive of industry he spent the remainder of his days, now residing at the Moseley Street Institution, where he studied and taught; then giving lessons privately, at the charge of 1s. 6d. an hour; next delivering public lectures, and by different literary and scientific labours eking [p.251] out a humble income until he received a royal pension, first of £150 and then of £300 per annum. Remaining a bachelor all his life, his wants were few; and to all worldly ambition he was a perfect stranger—dwelling amongst his own people, wearing a Quaker garb, using Quaker speech, cultivating Quaker habits, and stepping outside his religious circle only to associate with scientific men, in whose estimation he gradually rose to the highest pinnacle of eminence. He was welcomed in Paris with great applause, and on his return home he remarked: “If any Englishman has reason to be proud of his reception in France, I am that one.” The Royal Society of London awarded him their gold medal, and at Oxford he received the honorary degree of d.c.l. It is curious to find that, when at Cambridge, Professor Whewell asked him to what he could compare his doctor’s scarlet gown, and in return he pointed to the leaves of the trees. He was colour blind, and thought “the face of a laurel leaf a good match to a stick of red sealing-wax; and the back of the leaf to the lighter red of wafers.” After his death, it may be observed in passing, his eyes were examined in compliance with his own instructions. He thought the peculiarity of his sight was owing to a peculiarity in the vitreous humour; but it turned out that the vitreous humour, which he thought was bluish, was really of a pale yellow, and when used as a lens presented no difference from an ordinary eye. The cause seems to have been, not in the optical apparatus, but in the condition of the brain or sensorium.

Dalton is considered to have belonged, not to the class of chemists represented by Priestley, Davy, and Leibig—enthusiastic and sanguine men, who by the [p.252] originality of their genius and their brilliant powers made vast leaps in their discoveries; but to a larger class, represented by Black, Cavendish, Wollaston and others, who relied on their patience and perseverance. Perhaps a sternness of character belonged to the latter class, whilst they were more indifferent to the opinion of others than their less plodding brethren. “With regard to myself,” remarks Dalton, at an anniversary meeting in Manchester, “I shall only say, seeing so many gentlemen present who are pursuing their studies, that if I have succeeded better than many who surround me in the different walks of life, it has been chiefly—nay, I may say, almost solely—from unwearied assiduity. It is not so much from any superior genius that one man possesses over another, but more from attention to study and perseverance in the objects before them, that some men rise to greater eminence than others. This it is, in my opinion, that makes one man succeed better than another.” The orderliness of his habits corresponded with the mental qualities to which he ascribed his success. He regularly attended the meetings of the Society of Friends; he also regularly spent Thursday afternoon at a bowling green. For more than forty years he dined on the same day at a friend’s house, and did not absent himself when the family were from home. He was punctilious to an extreme. When a student, who had missed one of his lectures, applied for a certificate, he replied, “If thou wilt come to-morrow, I will go over the lecture thou hast missed.”

The scientific path along which Dalton travelled has been described in the following way:

“The blind gentleman, Mr. Gough, who exercised [p.253] so beneficial an influence over his early days, added to his other tastes a love for meteorology. It was he, Dalton tells us, who first set the example of keeping a meteorological journal at Kendal, and his pupil appears to have soon acquired a relish for the same study. Doubtless he was influenced likewise by the magnificent scenery around him, of which he has left some eloquent descriptions, and was tempted by the peculiar facilities which the locality of his residence afforded for every kind of meteorological inquiry.”1 He made daily memoranda relative to the weather, and not content with the use of the rain-gauge, penetrated into the depths of meteorological science, inquiring into theories of the wind, the causes of alterations in the state of the atmosphere, and the phenomena of spontaneous evaporation. The books he wanted to help him at Kendal he found at Manchester, where, assisted and stimulated by the history of philosophy, he prosecuted his original researches with increased ardour.

In 1790, he wrote a paper describing “experiments and observations to determine whether the quantity of rain and dew is equal to the quantity of water carried off by the rivers, and raised by evaporation, with an inquiry into the origin of springs”—the whole of which demonstrated what we read in the Bible: “All the rivers run into the sea; yet the sea is not full: unto the place from whence the rivers come, thither they return again.” Experiments and observations on the power of fluids to convey heat; others on heat and cold produced by the condensation and rarefaction of [p.254] air; and again, additional ones on steam and vapour, followed in succession. He ascertained that when two elastic fluids are mixed together, there is no mutual repulsion of their particles; the particles of A do not repel those of B, as they do one another; and that the pressure, or whole weight, upon any one particle arises from those of its own kind. This led to important consequences. In 1803, he wrote on the absorption of gases by water and other liquids, and compared his gas dissolved in water to a pile of shot: a particle of gas, he says, pressing on the surface of water, is analogous to a single shot pressing upon the summit of a square pile of them.2 To this he added an inquiry into the relative weights of the ultimate particles of bodies, which was a subject, as far as he knew, entirely novel. He weighed gases, and published a table of the atomic weights, as he called them, of hydrogen, oxygen, carburetted hydrogen from stagnant water, and olefiant gas. He was thus conducted to the discovery of the laws of combining proportions.

“Dalton’s views of chemical combination, including both the facts and the hypothesis which expressed and explained them, are generally known as his atomic theory. To Dalton himself the evidence in support of the existence of ultimate indivisible particles appears to have seemed so conclusive, that he considered the doctrine of atoms in the light of an induction from the data furnished by observation and experiment; and this without reference to any other than purely physical questions. We cannot indeed sufficiently reiterate that he was an atomist before he was a chemist.

[p.255] In his lips, therefore, the name ‘atomic theory’ was consistent and had a clear meaning. It was John Dalton’s atomic theory of chemical combining proportions: his theory of atoms, connected with his discoveries in chemistry, so as at once to account for and expound them. To those, however, who cannot by any process of generalization establish to their own satisfaction, or to that of others, the actual existence of atoms (and it includes almost every one who thinks on the subject at all), and for whom the doctrine of atoms is only a questionable, and we may say an indifferent hypothesis, Dalton’s view is an atomic hypothesis of combining proportion. It matters comparatively little, however, whether we say atomic theory or atomic hypothesis, provided we keep perfectly distinct what is matter of assumption concerning atoms from what is matter of fact concerning laws of combining proportion.’’3

The word “atom” may be popularly used in the same way as the word “element.” It may be employed to indicate the minutest particle to which analysis can reduce a substance in nature, without intending thereby to affirm that such a particle can be analysed no further. What actually constitutes the primordial essence, or basis of matter, has been an inquiry agitated in all ages; and though different theories may be broached on the subject, absolute satisfaction is far from being reached. At all events, that point at which analysis is compelled for the present to stop may be, without danger of misapprehension, denominated an atom, leaving it still an open [p.256] question what an atom is. It may here be added, that for the word “atom” Davy substituted the word “proportion,” and Wollaston the word “equivalent,” which is now generally used ; and Dr. Whewell remarks, “The general laws of chemical combination announced by Mr. Dalton are truths of the highest importance in the science, and are now nowhere contested; but the view of matter as constituted of atoms, which he has employed in conveying those laws, and in expressing his opinion of their cause, is neither so important nor so certain.”4

“The announcement of the atomic theory to the chemists of Europe was like a lighted torch passed round among lamps trimmed and filled with oil, and ready to be kindled. Some heard with incredulity, like Davy, others with gladness, like Thomson, none probably, without astonishment, that the humble teacher of mathematics had extracted more meaning out of his imperfect and even inaccurate analysis than they—even Berzelius and Wollaston—out of their scrupulously exact ones. It was so, however. In Spain, France, Germany, Sweden, and elsewhere, many were seeking to discover the laws regulating chemical combination, every one of them probably acquainted with a wider range of chemical phenomena and a better analyist than Dalton; but he beat them all. So true is it, what Thomas Carlyle says, ‘the eye sees what it brings the power to see.’”

“At the time when he made his discovery, there was not a single chemical analysis which could properly be considered as correct; there was not a single gas [p.257] whose specific gravity was known with any approach to accuracy; and Dalton displayed infinite sagacity in coming so near the truth as he did. Since the introduction of the atomic theory, the knowledge of chemical combination has been simplified to an amazing extent, and the processes of analysis, which constitute the essence of chemistry, have assumed a degree of accuracy almost approaching to mathematical precision. Manufactures have been benefited as well as science ; the quantity of each constituent of any article can be regulated with perfect accuracy, so that there is no waste; and the result of the combination can be reckoned upon with unfailing certainty.”5

The chief laws of chemical combination, as stated by Dalton, are: that the same compound consists invariably of the same constituents: that the elements of every compound always unite in the same proportion by weight: that when any element is in more proportions than one, those proportions are multiples—1, 2, 3, 4 ; 6, 12, 18, 24; 8, 16, 24, 32, and so on: that if two substances combine in a certain proportion with a third, they continue in exactly the same proportion with each other: and that the combining proportion of a compound is the sum of its constituents.

Dalton lived to be seventy-eight. Seven years before his death he had a paralytic seizure, and a second followed in 1844. In the July of that year, an address was presented to him acknowledging his services, when, not being able to give an articulate reply, he handed a written paper to this effect: “I feel gratified by this testimony of kind regard offered to me by [p.258] my old associates of the Literary and Philosophical Society of Manchester. At my age and under my infirmities, I can only thank you for this manifestation of sentiments, which I heartily reciprocate.” A little more than a week afterwards, he quietly expired.

It is strange to find, that though a Quaker, he was laid in state in the Manchester Town Hall, and had a public funeral, much to the displeasure of the Friends, with whose tastes and habits it was utterly out of keeping: and could it have been proposed to the philosopher himself, it would have met with his firm, if not severe disapprobation.

No particulars respecting his religious history, except of the most general kind, have been preserved, that we are aware of; nor did he, we believe, publish any theological work whatever. Indeed, the body to which he belonged are on principle averse to the free expression of spiritual experience, and regard communion between the Christian and the Saviour as amongst the sacred secrets of the soul; nor, with few exceptions, have they been wont to publish works on theology in general. But Dalton’s steady attachment to Quaker principles from youth to old ago, indicate sufficiently the absence of all sympathy in his mind with that scepticism respecting revelation which has in some cases haunted scientific students. We think of him “at meeting,” as devoutly lifting up his heart to God in adoration and praise, as he silently mused on the power, and wisdom, and goodness of Him who “weighed the mountains in scales and the hills in the balance;” who “giveth rain in due season;” and who maketh “the dew to lie all night upon the branch.” And, as it has ever been the special vocation [p.259] of the society to testify to the immediate work of the Holy Spirit on the mind of man, he would recognise in the rain and the dew, whose laws he studied so wisely and so well, symbols of gracious operations still more precious than any which can be discovered in the depth of nature’s secrets.

1 British Quarterly Review, vol. i. p. 177. To the article on Dalton we are much indebted.
2 British Quarterly Review, vol. i. p. 181.
3 British Quarterly Review, vol. i. p. 183.
4 Hist. of Inductive Sciences, vol. iii. p. 127.
5 C. Knight’s Biog. Dict., art. “Dalton.”

Footnotes, originally at corresponding page bottom, have been renumbered and grouped at the end. Text from John Stoughton Worthies of Science (1879), 249-259, published by Religious Tract Society. (source)

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