Background
John Dalton was born in Eaglesfield, England, on September 6, 1766, to a Quaker family. He was the son of Joseph Dalton and Deborah Greenup Dalton. He had two surviving siblings. Dalton's father earned a modest income as a handloom weaver.
John grew up working in the fields and in the family shop where the cloth was made. His sister sold paper, ink, and pens, but despite all these sources of income they were relatively poor and the boys did not get much formal education.
Education
Dalton received his early education from his father. Later he attended Quaker school in his village in Cumberland and at the age of 12, he became a teacher there. After two years he took up farm work, but when he reached 15 his opportunity for further study materialized in an invitation to teach at Kendal as an assistant to his brother Jonathan. There his talent was recognized by the blind scientist John Gough, under whom Dalton studied science, literature, and languages.
One suggestion that Gough made to Dalton was to keep a daily log of the weather and matters meteorological. So he started writing down what he saw and what he measured about the weather patterns in a book, every day. He kept this journal for his entire life, and probably the very last thing he did on the day he died, was to make his final entry.
All the while, he continued teaching himself science, mathematics, Latin, Greek, and French. By the time he was 19, he had become the school's principal, continuing in this role until he was 26 years old.
In 1832 he did, however, begrudgingly accept an honorary Doctorate of Science degree from the prestigious Oxford University. Dalton was offered another degree, this time a Doctorate of Laws, by Edinburgh University in 1834.
Career
John Dalton was inspired by Gough to investigate meteorology, and beginning in 1787 Dalton kept a meteorological diary for 57 years, which eventually contained approximately 200,000 observations. In 1792 he published "Meteorological Observations and Essays," a work that can be said to mark the beginning of meteorology as a science. In the same year, he became a tutor at New College, Manchester, and in 1793 he made a study of red-green color blindness, technically termed protanopia but still widely known as Daltonism.
In 1794, he wrote his first scientific paper which he called Extraordinary Facts Relating to the Vision of Colours.
This was the first-ever paper to discuss color blindness. Dalton had realized the condition was hereditary because he and other members of his family had it. Ultimately, Dalton's theory for color blindness was wrong, but as he was the first person ever to research it, the condition became known as Daltonism.
After this, he published more research papers in the physical sciences looking at heat conduction, gas expansion by heat, the properties of light, the aurora borealis, and meteorology.
In 1800, Dalton resigned from New College, which was in financial difficulty, and began working as a private tutor of science and mathematics.
In 1801, Dalton gave a series of lectures in Manchester whose contents were published in 1802. In these lectures, he presented research he had been carrying out into gases and liquids. This research was groundbreaking, offering great new insights into the nature of gases.
Firstly, Dalton stated correctly that he had no doubt that all gases could be liquefied provided their temperature was sufficiently low and pressure sufficiently high. He then stated that when its volume is held constant in a container, the pressure of a gas varies in direct proportion to its temperature. This was the first public statement of what eventually became known as Gay-Lussac's Law, named after Joseph Gay-Lussac who published it in 1809.
In 1803, Dalton published his Law of Partial Pressures, still used by every university chemistry student, which states that in a mixture of non-reacting gases, the total gas pressure is equal to the sum of the partial pressures of the individual gases. In 1804, Dalton also proposed a system of chemical signs for "simple" and "complex" atoms.
Dalton's work distinguished him as a scientist of the first rank, and he was invited to give lectures at the Royal Institution in London.
In 1833 the government granted him a pension, which was doubled in 1836. In his later life, Dalton continued to teach and lecture at universities throughout the United Kingdom.
Religion
Throughout his lifetime, Dalton managed to maintain his nearly impeccable reputation as a devout Quaker.
Views
Dalton's interest in atmospheric pressures eventually led him to a closer examination of gases. While studying the nature and chemical makeup of air in the early 1800s, Dalton learned that it was not a chemical solvent, as other scientists had believed. Instead, it was a mechanical system composed of small individual particles that used pressure applied by each gas independently.
Dalton's experiments on gases led to his discovery that the total pressure of a mixture of gases amounted to the sum of the partial pressures that each individual gas exerted while occupying the same space. In 1803 this scientific principle officially came to be known as Dalton's Law of Partial Pressures. Dalton's Law primarily applies to ideal gases rather than real gases, due to the elasticity and low particle volume of molecules in ideal gases. Chemist Humphry Davy was skeptical about Dalton's Law until Dalton explained that the repelling forces previously believed to create pressure only acted between atoms of the same sort and that the atoms within a mixture varied in weight and complexity.
The principle of Dalton's Law can be demonstrated using a simple experiment involving a glass bottle and a large bowl of water. When the bottle is submerged underwater, the water it contains is displaced, but the bottle isn't empty; it's filled with the invisible gas hydrogen instead. The amount of pressure exerted by the hydrogen can be identified using a chart that lists the pressure of water vapors at different temperatures, also thanks to Dalton's discoveries. This knowledge has many useful practical applications today. For instance, scuba divers use Dalton's principles to gauge how pressure levels at different depths of the ocean will affect the air and nitrogen in their tanks.
During the early 1800s, Dalton also postulated a law of thermal expansion that illustrated the heating and cooling reaction of gases to expansion and compression. He garnered international fame for his additional study using a crudely fashioned dew point hygrometer to determine how temperature impacts the level of atmospheric water vapor.
Dalton's fascination with gases gradually led him to formally assert that every form of matter (whether solid, liquid, or gas) was also made up of small individual particles. He referred to the Greek philosopher Democritus of Abdera's more abstract theory of matter, which had centuries ago fallen out of fashion, and borrowed the term "atomos" or "atoms" to label the particles. In an article he wrote for the Manchester Literary and Philosophical Society in 1803, Dalton created the first chart of atomic weights.
Seeking to expand on his theory, he readdressed the subject of atomic weight in his book "A New System of Chemical Philosophy," published in 1808. In "A New System of Chemical Philosophy," Dalton introduced his belief that atoms of different elements could be universally distinguished based on their varying atomic weights. In so doing, he became the first scientist to explain the behavior of atoms in terms of the measurement of weight. He also uncovered the fact that atoms couldn't be created or destroyed.
Dalton's theory additionally examined the compositions of compounds, explaining that the tiny particles (atoms) in a compound were compound atoms. Twenty years later, chemist Amedeo Avogadro would further detail the difference between atoms and compound atoms.
Quotations:
"Matter, though divisible in an extreme degree, is nevertheless not infinitely divisible. That is, there must be some point beyond which we cannot go in the division of matter. ... I have chosen the word "atom" to signify these ultimate particles."
"If I have succeeded better than many who surround me, it has been chiefly - may I say almost solely - from universal assiduity."
"No new creation or destruction of matter is within the reach of chemical agency. We might as well attempt to introduce a new planet into the solar system, or to annihilate one already in existence, as to create or destroy a particle of hydrogen."
"The cause of rain is now, I consider, no longer an object of doubt. If two masses of air of unequal temperatures, by the ordinary currents of the winds, are intermixed, when saturated with vapour, precipitation ensues. If the masses are under saturation, then less precipitation takes place, or none at all, according to the degree. Also, the warmer the air, the greater is the quantity of vapour precipitated in like circumstances. ... Hence the reason why rains are heavier in summer than in winter, and in warm countries than in cold."
"Reconsidering Happiness captures all the contradictory impulses of falling in and out of love-the lust and wanderlust, the contentment and restlessness, the secret loyalties, the hard compromises. Sherrie Flick has written a wise and elegant novel."
"I spent several years acquiring the obsessive, day-to-day discipline that's needed if you want to write professionally, then several more, highly valuable years studying fiction writing at the University of Iowa."
"Berzelius' symbols are horrifying. A young student in chemistry might as soon learn Hebrew as make himself acquainted with them... They appear to me equally to perplex the adepts in science, to discourage the learner, as well as to cloud the beauty and simplicity of the atomic theory."
"We should scarcely be excused in concluding this essay without calling the reader's attention to the beneficent and wise laws established by the author of nature to provide for the various exigencies of the sublunary creation, and to make the several parts dependent upon each other, so as to form one well-regulated system or whole."
Membership
From 1817 to the day he died, John Dalton served as president of the Manchester Literary and Philosophical Society, the organization that first granted him access to a laboratory. A practitioner of Quaker modesty, he resisted public recognition; in 1822 he turned down elected membership to the Royal Society.
Personality
Dalton had a gruff, quiet, inexpressive voice, besides that the scientist was too complicated to explain even the simplest things.
Many historians think that Dalton chose to study gasses because of his interest in meteorology, a life long interest in which he collected over 200,000 observations. Even when trying to relax, Dalton could not, however, stop keeping records. One of his few methods of relaxation was to go to a pub called the "Dog and Partridge," just outside town. Every Thursday he bowled heavy black wooden balls across a perfectly kept green lawn (the English call this game "Bowls") and tried to hit a tiny white one.
Physical Characteristics:
Both John and his brother were born color-blind.
Quotes from others about the person
"Now with nanotechnology, atoms are the centerpiece. Atoms are manipulated directly to make new medicines, semiconductors, and plastics. He gave us the first understanding of the nature of materials. Now we can design molecules with a pretty good idea of their properties." - David Garner
"Dalton was very much an icon for Manchester. He is probably the only scientist who got a statue in his lifetime."
