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HE visitor to the finest town- different atoms of matter. Upon that hall in the world, that of and what naturally followed it, he says, Manchester, England, sees in all the edifice of modern chemistry rests. the vestibule of that magnifi- Dalton laid this foundation-stone in a
cent municipal temple two modest statement, read on October 21, life-size marble statues facing each other. 1803, to the Philosophical Society of They are described by Manchester's most Manchester. conspicuous citizen, the eminent chem- Dalton, who was born September 6, istry professor, Sir Henry E. Roscoe, as 1766, was a full generation before Joule, presentations in marble of “two giants whose birth occurred December 24, 1818, in science"-"Dalton, the founder of and who became a pupil of Dalton for modern chemistry,” and “Joule, the three or four years in the study of physics, founder of modern physics.”
through which, by his later years of reSir Henry assigned to Dalton his dis- search, he was destined to obtain a great tinction on the ground that he was the fame. discoverer of what is known in science A very interesting fact in regard to as the “atomic theory," under which are Dalton not only appears from the story grouped the laws of chemical-combining of his life, but is expressly brought out proportions. Joule's distinction Sir Henry in statements made by Sir Henry Roscoe. bases upon the fact that he was the dis. It is that he was wholly self-educated, coverer of what is known as the law of and that he believed very little in educathe conservation of energy. Dalton, he tion that was not self-education. The says, gave to the world the final proof fact that Dalton“ began about 12 to that, in chemical changes, whatever new teach the village school, and continued it combination may be made, there is no two years,” sufficiently indicates that the loss of matter; every atom can be ac- boy got at work without having spent a counted for, and the change which very long time in the pursuit of learning. has affected it exactly traced. In the Sir Henry's statement just mentioned, is same way, says Sir Henry, Joule dealt as follows: with energy, proving that none is ever “From the age of 12 up to his death, lost, and that all changes affecting it can Dalton earned his living as a schoolbe exactly followed and understood. master, but not an ordinary one ; for,
The great foundation-stone in chemical having set his pupils to their lessons, and science, says Sir Henry, was Dalton's de- having given them a hint how to proceed, termination of the relative weights of the he would leave them pretty much alone,
Copyright, 1895, by THE WERNER COMPANY. All rights reserved. 369
believing in the doctrine, which he had expositor of science from the platform of practiced throughout his life, that self- the lecturer, and with the rough exterior education is the only true one."
and uncouth demeanor of his earlier And it is of interest to remark that years, not to speak of his Cumberland Joule, who after Dalton trod the path dialect, which said “Yan med deu't” of eminence in discovery, was a pupil of for “You may do it,” his public efforts Ialton, taking for three or four years could not have added much either to his private lessons in physics, and beyond income or to his courage in pursuicg tnis was entirely self-educated in science, thankless tasks. Happily, the indomitabecoming very early an enthusiast in ble energy of his character made him inoriginal research, and the maker at 19 of dependent of aids of circumstance. an electro-magnetic engine.
In these earlier years he made botanDalton was born, the son of a hand- ical collections, when as yet scientific loom weaver, September 6, 1766. His botany was non-existent, and went from parents were Quakers, and he was through- plants to insects without help from enout life a singularly fine type of the tomology. “Some of these," he wrote, Quaker man; sometimes, not to say “may be thought puerile; but nothing often, a plain, almost brusque man; at that enjoys animal life, or that vegetates, other times a singularly interesting gen- is beneath the dignity of a naturalist to tleman. The boy Dalton, although he examine.” He experimented on the vidid so much for himself, was yet partic- tality of snails, mites and maggots, and ularly helped in starting by an excellent upon his own vital energy in its connecQuaker schoolmaster to whom he was tion with food, seeking to penetrate the sent, and also by a Quaker gentleman cause of disease and of health," and for of some scientific and literary distinction, a time seriously thinking of taking mediwho not only assisted young Dalton in. cine as his profession. his studies, but gave him special instruc- On coming to Manchester, in 1793, tion. The early schooling which he had, Dalton became tutor in mathematics and until 11 years of age, carried him through natural philosophy and chemistry in an a course of mensuration, surveying, nav institution of high and liberal aims, which igation, etc.
stood as an academy at Manchester until
1803; then found a seat at York until Teacher and Stu- The school of which the 1840, again rested a short time at Mandent of Nature
Quaker youth was prin chester, as “Manchester New College;' cipal at twelve years of age, was car- and after transference to London, where, ried on in an old barn at first, then in his from 1853, the celebrated Dr. James Marfather's cottage, and later in the Quaker tineau was its chief light, was in 1889 meeting-house. The emoluments were made the chief English liberal divinity not over about $1.25 a week; worth, per- school as “Manchester College," at haps, at that time, as much again as at Oxford. present. After two years of this, the After six years of such service in teachyouth tried work with a farmer, and fol- ing science as his tutorship involved, lowed the plow as possibly more remu- Dalton resigned his post, to devote himnerative than playing pedagogue on a self more freely to researches in science, small scale.
while giving lessons to private pupils as a At 15 years of age Dalton walked means of support. From his experience forty-four miles from his country home as a teacher, and his admiration for the to Kendal, a considerable town, where writings of Horne Tooke, he wrote an his brother and a friend were carrying on English grammar, which was published in a school. His school-keeping at Kendal 1801, but secured little if any sale. continued for twelve years, until 1793, when he found a place as teacher at Man- Meteorological With the keen intellichester for six years, after which he was
Researches gence of a thorough stua private teacher, devoting a great part of dent, he had entered, at a very early his time to researches in science.
date, upon meteorological observations, As early as 1787 Dalton began with and these he pursued to the end of his public lectures, to which from that time, life. In aid of his earlier attempts he for some years, he devoted considerable constructed for himself barometers and attention. He never became a popular thermometers, and became in a modest way a manufacturer of these instruments. ignorant, to a great extent, of what had A volume of his meteorological observa- been written by others, and out of reach tions was published in 1793. From about of libraries and books of reference. 1792, when he had an opportunity, on Dalton's study of evaporation led to a October 13th, to observe a grand auroral law of vapors, which is called his, and display, Dalton made a special study of according to which it is understood that the connection between auroral displays aqueous vapor always exists independand the earth's magnetism. Living, as ently in the air, not held by or attached he did, for twenty-six years, in the beau- to the oxygen or nitrogen of the air, and tiful lake district of the northwest of Eng. that the same weight of the vapor is land, not only the hills and the lakes, the taken up by a given space, at a given defells and the streams, became familiar to gree of heat, whether that space be or be him, but the changing skies, the varying not filled with air. climate, and the heavens at night, were the pages of a great book of nature in The Theory Dalton was the first, not which he took unwearied delight, and
of Rain indeed to suggest, but to from which he drew lessons of knowledge render certain, that rain is caused, not by such as books could not give him. It any alteration in atmospheric pressure but was, indeed, characteristic of his self-edu- simply and solely by a diminution of temcated originality, that he preferred to be perature. He made clear that when moist independent of what books could tell him, air is cooled below what we know as the and to speak as much as possible from his dew-point, the aqueous vapor in a very own observations and experience. In the fine form condenses into larger particles, matter of the auroral light, which, says forming clouds, and upon further condenSir Henry Roscoe, has been made to tell sation giving drops, which fall as rain; us its story, yet without permitting us to an enormous weight of water thus falling: read the riddle of a bright green line from a cubic mile of air, for instance, always found in its spectrum, Dalton which is a minute fraction of the whole guessed correctly its connection with the over any locality, no less than 140.000 earth's magnetism; but to this sound tons of rain or snow falling, if the air, at judgment he added the assumption, which 95° of summer heat, has taken up all that our knowledge now fails to support, that it can, and precipitation is brought about there must be something of the nature of by the temperature falling to the freezing iron or magnetic steel in the auroral beam. point.
The Causes The attention which Dal- Rer
Remarkable Long before Faraday had of Windston gave to atmospheric
Prediction published his first experdisturbances, without knowing that the iments, in 1821, on the condensation of history of the subject already formed a the so-called permanent gases, Dalton chapter of sound science, led him to the predicted, not only what Faraday accomwholly true, complete, and accurate con- plished, but what we now know, that all clusion, that “the inequality of heat in the gases, including probably even hydrogen, different climates and places, and the which is found to be by far the most reearth's rotation on its axis, are the grand fractory, can be liquefied, and even solidand chief causes of winds, both regular ified. “There can scarcely be a doubt and irregular, in comparison with which entertained,” he said, “respecting the all the rest are trifling and insignificant.” reducibility of all elastic fluids [i. e. gases]
In this connection Sir Henry Roscoe of whatever kind into liquids; and we remarks that Dalton's essays on the ba- ought not to despair of effecting it in low rometer, on the thermometer and their temperatures, and by strong pressure exvariations, on the aurora, on rainfall, on erted upon the unmixed gases." the formation of clouds, on evaporation, A paper which Dalton brought to noand on the distribution and character of tice June 27, 1800, dealt with “the heat atmospheric moisture, written, as they and cold produced by the mechanical conwere, at the end of the last century, densation and rarefaction of air,” in a might well be considered as remarkable way to suggest that equivalency of meproductions from the pen of an expe- chanical energy and heat which was rienced philosopher; although they were, afterwards fully studied out by Manchesin fact, written by a young schoolmaster, ter's other eminent discoverer in science,
Joule, the founder of modern physics. color, which descends pretty uniformly Dalton made the first attempt to measure from an intense to a rare yellow, making the amount of heat evolved by compres- what I call different shades of yellow. sion and that absorbed in rarefaction, and The difference between the green part it was when, forty years after, his deter- and the blue part is very striking to my minations were repeated, that an advance eye; they seem to be strongly contrasted. began to which Joule gave monumental That between the blue and purple is completion.
much less so. The purple appears to be At this date, 1800, Dalton became sec- much darkened and condensed. retary to the Manchester Philosophical “Under Red (by daylight) I include Society. He became a vice-president in crimson, scarlet, red, and pink. All crim1808, and from 1817 to his death, in sons appear to me to consist chiefly of 1844, he filled the office of president, dark-blue ; but many of them seem to and gave to the world, through it, the have a strong tinge of dark-brown. I long series of his masterly researches. have seen specimens of crimson, claret,
and mud which were very near alike. Color Vision A most remarkable and Crimson has a grave appearance, being
Experiences interesting chapter in the the reverse of every showy and splendid story of Dalton's life is that of his expe- color. Woolen yarn, dyed crimson or ricnce of wrong color-vision, seeing cer- dark-blue, is the same to me. Pink seems tain colors wrongly, and the researches by to be composed of nine parts of light-blue which he made the subject of such wrong and one of red, or some color which has color-vision known to the scientific world. no other effect than to make the lightHe had lived to the age of 26 before he blue appear dull and faded a little. became aware that he saw certain colors “The color of a florid complexion apwrongly; scarlet, for instance, being seen pears to me that of a dull, opaque, blackby him as drab. The story goes that ish-blue upon a white ground. Dilute when he made his Quaker mother a pres- black ink upon white paper gives a color ent of a pair of stockings marked in a resembling that of a florid complexion. shopwindow “silk, and newest fashion," It has no resemblance of the color of she found them to be a bright scarlet, blood. Blood appears to ine not unlike while to his sight they were a dark-bluish that color called bottle-green. drab. He and his brother Jonathan both “By candle-light red and scarlet apsaw them as drab, and insisted that their pear much more vivid than by day. mother's eyes must see wrong. Her Crimson loses its blue and becomes yelneighbors, however, sustained her decla- lowish-red. Pink is by far the most ration that the stockings were “varra fine changed-indeed, it forms an excellent stuff, but uncommon scarlety." It further contrast to what it is by day. No blue proved that Dalton saw green as a reddish now appears; yellow has taken its place. snuff color. At a tailor's he proposed to Pink, by candle-light, seems to be three have a coat of Quaker drab made from a parts yellow and one red, or a reddishpiece of such scarlet cloth as was in use yellow. The blue, however, is less mixed for hunting-coats. Pink he saw as sky by day than the yellow by night. Red, blue. Pinks and roses he saw as light- and particularly scarlet, is a superb color blue by day and a reddish-yellow by by candle-light; but by day some reds night; crimson as a bluish-dark drab, and are the least showy imaginable. I should grass-green as a red or blood color. The call them dark drabs. rosy blush of a cheek was to him a light- “I do not find that I differ materially blue. While persons ordinarily see red, from other persons in regard to orange orange, yellow, green, blue, and purple, and yellow, by daylight and by candlehis sight he described as follows :
light. “My yellow comprehends the red, “Green, by daylight, I take my idea orange, yellow, and green of others; and of from grass. This appears to me red; the my blue and purple coincides with theirs. face of a laurel leaf a good match to a stick That part of the image [of the sun, the of red sealing-wax,and the back of the leaf colors of the spectrum] which others call the lighter red of wafers. Green woolen red, appears to me little more than a cloth appears to me a dull, dark, brownshade, or defect of light ; after that, the ish-red color. A mixture of two parts orange, yellow, and green, seem one mud and one red would come near to it. When this kind of cloth loses its color 3. The quantity of any liquid evapoand turns yellow, then it appears to me a rated in the open air is directly as the force pleasant green. Very light green paper, of steam from such liquid at its tempersilk, etc., is white to me.”
ature, all other circumstances being the In explanation of these remarkable same. variations of vision from the common, 4. All gases expand the same quantity Dalton thought it beyond doubt that one by heat, and very nearly in the same of the humors of such an eye as his must equable way as mercury. be colored; the vitreous humor, as he im- The expansion of gases and vapors by agined, having a blue color, or some heat was discussed and its law established modification of blue. This explanation by Dalton, who found that for equal inis known to be erroneous, but what the crements of temperature all gases expand true explanation is has not been made out. equally. This law is properly called
Dalton's, because he first announced it Self-Education The eminence of Dal- and gave experimental evidence of its
in Chemistry ton as a discoverer in truth. chemistry was achieved without any aid In the essay on this law Dalton gave a from education in that science. Up to diagram to illustrate his conception of the 1796, when he was 30 years old, there is constitution of the air, which indicates no evidence that he had taken any spe- that his mind had begun to distinctly cial interest in chemical research. But picture atoms as composing gases. when his interest had been excited by Further experimental inquiry brought hearing a course of lectures on chemistry, out the fact that the oxygen and nitrogen he at once undertook experiments, and of the air exist in a constant definite occupied his mind with reflections look proportion which may be roughly stated ing to finding out the laws of chemical at that of oxygen one part, and nitrogen change.
four parts, the two gases being diffused He saw clearly that study of the chem precisely as either would be in a vacuum. ical and physical properties of gases especially, promised revelation of the se- Germ of Great The first germ of his crets of nature which he desired to pene
Discovery great discovery of the trate. He succeeded, according to his law of chemical combination in multiple own view, not so much from having any proportions appears in his making out the exceptional genius as from unwearied fact that when oxygen and nitrous gas assiduity in research. Yet his unwearied are united it appears that the oxygen attention to study, and his untiring per- may unite with one definite portion of severance, were not without a high de nitrous gas, to form nitric acid, and with gree of genius or intellectual insight. twice that portion, neither less nor more,
to form nitrous acid Here was the first Discovery of As early as October of inkling got by Dalton of his great law,
Important Laws 1801. Dalton gave a se- according to which chemical combination ries of papers on the constitution of proceeds, not by indefinite varying mixed gases, in which were brought to amounts uniting, but by a definite invariview four important laws which form the able portion, or number of portions-one, basis of our present knowledge. By two, or three full portions, and never these laws were brought out the facts: some part of a portion.
1. That when two gases are mixed to. The investigation by Dalton of the gether, as oxygen and nitrogen, in the way in which a gas is dissolved in and air, their particles do not mutually repel diffused through water, contributed some each other, or press upon each other, but light in the direction of the theory of those of each gas move and are pressed atoms which he was rapidly working out. precisely as if those of the other were not Heconceived the gas as a mass of particles present.
which move about in the water, mutually 2. The force of steam from all liquids repelling one another, precisely as in a is the same at equal distances above or vacuum. Some altogether erroneous ideas below the several temperatures at which were brought by Dalton into his theorv they boil in the open air, and is the same of the solubilty of gases in water, but out under any pressure of another gas as it of it all came the grand discovery embodwould be in a vacuum.
ied in a “ Table of Relative Weights of