« PoprzedniaDalej »
tions contained in them. He also formed a very valuable friendship with Mr. John Gough, a blind philosopher of remarkable attainments in mathematics, philosophy and natural history, to whom he afterwards warmly expressed his great obligations in his published works. It was he who first set the example of keeping a meteorological journal in Kendal. Dalton further manifested his grateful sense of the benefits he had derived from this friend and instructor by the calmness of his replies to the somewhat angry criticisms of Mr. Gough on his subsequent discoveries. Dalton himself commenced a meteorological journal on March 24, 1787, with the observation of a remarkable Aurora Borealis which appeared on that day, and which may probably have suggested the commencement of his journal. The phenomena connected with the Aurora Borealis occupied much of his attention in after life. At this time he carried on an extensive correspondence with Mr. Crosthwaite, the founder of the Keswick Museum, who conducted a series of meteorological observations simultaneously with himself. He also made a collection of dried plants, now preserved in that museum, and bestowed some attention to entomology, observing the changes of caterpillars, and the power of a vacuum or immersion in water to destroy or suspend vitality in snails, mites and maggots. In sending some specimens of butterflies and ichneumon flies for the museum, he observed apologetically, “They may perhaps be deemed puerile; but nothing that enjoys animal life or that vegetates, is beneath the dignity of a naturalist to examine." Early in the year 1790, he made an elaborate series of observations on his own person, with the view of ascertaining the weight lost by insensible perspiration. These observations formed the subject of a paper, forty years afterwards, in the Memoirs of the Manchester Society, and also of a communication to the British Association. At this time he appears to have had thoughts of entering the medical profession,-a project, however, which his friends strongly discountenanced. He twice delivered at Kendal (1787 and 1791) a course of twelve lectures on Natural Philosophy, the terms of admission being the first time 10s., and the second time 58., the course. From this time it became part of his regular occupations, and an important source of his slender income, to deliver lectures at Manchester and elsewhere.
In the spring of 1793, he was invited by Dr. Barnes, of Manchester (on the recommendation of Mr. Gough), to be Tutor in Mathematics and Natural Philosophy to the College founded by the English Presbyterian Dissenters. The terms were, that he should receive three guineas from each student in his class, with the guarantee that the sum should not fall short of £80 per session of ten months. Commons and rooms in the College were allotted him at £27. 10s. per session. He held this appointment for six years (at the end of which time the College was
removed to York), but resided in Manchester for the remainder of his life. It is always difficult to pronounce how far the career of a man of genius is really determined by external circumstances; but certainly, to human judgment, it appears that Dalton's appointment at Manchester College was an important turning-point in his philosophical career. It was soon after his removal to Manchester that he published his first work, his " Meteorological Observations and Essays," the materials of which he had accumulated during his long residence in the mountainous region of the Lakes. In 1794, he became a member of the Manchester Literary and Philosophical Society, of which he filled in succession all its offices of honour, until, in 1817, he was elected President, which he continued to be till his death, when he was succeeded by the late Dr. Holme, himself a native of Kendal. The Society permitted him to occupy one of the lower rooms of their building as a study and laboratory. In this room the larger portion of his subsequent life was spent, in private tuition and in the prosecution of his researches. In return for this liberality on the part of the Society, he published in their Memoirs the long series of important papers in which his successive discoveries were first made known.
In 1801, he published a work on quite a different subject, namely, his Elements of English Grammar, in which he acknowledges his obligations to Horne Tooke. This reminds us that we think we remember hearing that English composition was included in the instruction given by him in Manchester College, and that his lessons in that department were very valuable, as he never would permit any unmeaning or superfluous words. He was indeed an invaluable instructor, in any exact science, to careless, indolent or superficial minds. No smattering, showy half-knowledge would go down with him. He never would allow anything to be taken for granted. Every problem must be worked out, and the reason of every rule thoroughly understood; so that though the pupil's progress might at first seem slow, it was sure; the lessons were securely built on a solid foundation of clear intelligence, and whatever was learned with him could not easily be forgotten. The severe and rigorous simplicity of his lessons afforded a striking contrast to the florid and wordy declamations with which the late Dr. Chalmers is recorded to have embellished his mathematical lectures.
His biographer remarks, that “there occur numerous indications, in his letters and journals of this period, that Dalton, unlike Cavendish, but like most men of higher sensibility and intelligence, greatly enjoyed the society of women of superior talents and mental culture.” Interesting extracts are appended in proof, together with some really very respectable “ Stanzas to an Eolian Lyre," the subject of which, however, might possibly have special interest for him as an atmospheric phenomenon. It is added, that “though not endowed with lively sensibilities, nor with taste for art or poetry, he was deeply moved by simple melodies, and would sit absorbed and spell-bound by certain favourite airs.” In his journal for 1795, he has stated that, with another Friend, he “ drew up a petition to the yearly meeting, soliciting permission to use music under certain limitations.”
In the winter of 1803-4, he had the honour of being invited to lecture before the Royal Institution in London, where he was received with great kindness by Mr. (afterwards Sir H.) Davy, and listened to with much attention by his scientific hearers. He never became a popular lecturer, however, not having any graces of manner or style, and not being ready or successful in his experimental illustrations. Towards the close of the year 1805, he took up his abode as an inmate with his friend the Rev. W. Johns and his family, in George Street, nearly opposite his laboratory.
“Miss Johns has thus recorded the characteristic simplicity with which this engagement was formed :—“As my mother was standing at her parlour window one evening towards dusk, she saw Mr. Dalton passing on the other side of the street, and on her opening the window, he crossed over and greeted her. “Mr. Dalton,' said she, “how is it that you so seldom come to see us? Why, I don't know,' he replied; but I have a mind to come and live with you. My mother thought at first that he was in jest, but finding that he really meant what he said, she asked him to call again the next day, after she should have consulted my father. Accordingly, he came and took possession of the only bedroom at liberty, which he continued to occupy for nearly thirty years. And here I may mention, to the honour of both, that throughout that long connection, he and my father never on any occasion exchanged one angry word, and never ceased to feel for each other those sentiments of friendly interest which, on the decline into years of both, ripened into still warmer feelings of respect and affection.'"*
Thenceforward, so long as health and strength endured, he led a life remarkably uniform in tranquil devotion to scientific pursuits, seldom varied except by a weekly half-holiday in the country and an annual summer excursion. Every Thursday afternoon it was his habit for many years to spend with a party of friends in a game at bowls at Throstle Nest, near Manchester, and it is said to have been extremely amusing to watch his eagerness when he had delivered the bowl, running after it across the green, stooping down as if talking to it, and waving his hands from one side to the other as he wished the bias to be. His summer vacation he almost invariably spent in rambling over the hills in the Lake district, in company with philosophical friends, being a hardy and active pedestrian, and combining the pursuit of health and enjoyment with meteorological observations, in
* Pp. 63, 64.
which indeed a great part of his enjoyment consisted; generally carrying with him a portable barometer to measure the heights of the mountains, and a bottle to be filled with air for subsequent analysis. In this manner he paid many visits to the summit of Helvellyn, in some of the recesses of which on the eastern side he knew where to find snow in the height of summer. A pleasant account of these mountain rambles is given by his friend Mr. Jonathan Ottley, of Keswick, who was his companion in many of them. He mentions an accidental meeting in July, 1824, between Dalton and Professor Sedgwick at Wythburn, which was mutually gratifying, and was afterwards alluded to by the Professor in his eloquent address at the Cambridge meeting of the British Association.
Early in 1818, Mr. Dalton was invited by Sir H. Davy, on the part of the Royal Society, to join the expedition to the Polar Regions under Sir John Ross, which, however, he respectfully declined. In 1816, he was elected a corresponding member of the French Academy of Sciences, on the subject of chemistry, an honour which had previously been conferred on no other Englishman, with the exception of Dr. Wollaston. It was not till March, 1822, that he was received into the Royal Society; but he seems to have been deterred from being proposed as a candidate earlier, by the amount of the admission fee and composition. In the summer of 1822, he visited Paris, together with two friends, where he was received with a distinction to which he had up to that time known nothing comparable in his own 'country, and had much pleasure in making the personal acquaintance of such men as Berthollet, Biot, Cuvier, Laplace, Brègvet, &c., all of whom paid him the greatest attention. He was not deterred by the habits of his sect from visiting the Italian Opera and the Théatre Français. He was much interested in obserying the solemnities of the Roman Catholic worship, and much impressed by the gallery of the Louvre. In 1826, the Royal Society awarded to him one of the two royal prizes of fifty guineas for his discoveries in chemical science, which was announced in appropriate terms by the President, Sir H. Davy, in his anniversary discourse. In 1830, the French Academy of Sciences raised him from the class of Corresponding Member to the rank of one of its eight Foreign Associates,-the highest station it has to bestow, and universally regarded as the crowning distinction in European science. He thus became one of a list of illustrious men, commencing with Newton, Leibnitz and Peter the Great, and his immediate predecessor was Sir H. Davy. Mr. Dalton was present at the first meeting of the British Association at York in 1831, and attended the annual meetings as long as his health permitted. It was on occasion of the second meeting at Oxford in 1832, that the honorary degree of D.C.L. was conferred upon him, at the instigation, we believe, of Dr.
Daubeny, and at the same time with Faraday, Mr. Robt. Brown and Sir David Brewster. Here came into play that remarkable peculiarity of vision by which he was able to distinguish only two out of the three primary colours, and could see no difference between scarlet and green or drab. Professor Sedgwick informs his biographer-"Some one, I forget who, quizzed him about his scarlet covering, while we were before Magdalen College. 'You call it scarlet,' said Dalton; 'to me its colour is that of nature—the colour of those green leaves,' pointing to the trees."* Although a member of the Society of Friends, he was thus able without difficulty to acquiesce in some of the vanities of the world, and literally to “be to their faults a little blind.” This peculiarity of vision has been named, by the continental philosophers, Daltonism; but Dr. George Wilson very reasonably objects to the principle of thus immortalizing great men in connection with their personal defects. On this principle, he says, " the possession of a stutter would be called Demosthenism; that of a crooked spine, Esopism; the lack of an arm, Nelsonism, and so on.” “Professor Whewell sought to better the matter by naming those affected with Dalton's peculiarity of vision, Idiopts ; but to this name it was justly objected, by Sir David Brewster, that the important consonant p would be very apt to be omitted in hasty pronunciation, and so the last state of the Idiopt would be worse than the first.”+ The name “ Colour-blindness," proposed by Sir D. Brewster, seems unobjectionable. Dalton himself, who made his peculiarity of the vision a subject of investigation, conceived it to be owing to a blue colour in his vitreous humour; but after his death, when, in pursuance of his own request, the eye was carefully examined by his medical attendant, Mr. Ransome, no peculiarity whatever could be discovered, shewing that the deficiency must have been owing to some peculiar condition of the brain or sensorium. He states that Mr. Bally, the phrenologist, was present at the examination, and “pointed out a remarkable prominence on the frontal portion of the orbitar plates (which represents the phrenological site of the
organ of colour'), and the deficient development of the anterior lobes, which rested upon it. Of course Mr. Bally adopted this as the true explanation of the peculiarity of Dalton's vision."I
In the summer of 1833, Lord Grey's Government conferred upon Dr. Dalton an annual pension of £150, which was shortly afterwards doubled. At this time, the popular feeling against all pensions whatever was so strong as to make this a matter of some difficulty ; but it was effected principally through the earnest efforts of Mr. G. W. Wood and Mr. Babbage, aided by an eloquent and beautiful memorial from the zealous pen of the late Dr. Henry. The pension was announced in appropriate
* P. 172.
† Brit. Quart. Rev. Vol. I. p. 194.
Pp. 201, 202.