John Dalton


Early Life

John Dalton was born in a small English village named Cumbria in 1766, the third of an eventual six children. He was the son of a poor hand-loom weaver, and was educated through his attendence of a local Quaker school. Aged 12, Dalton finished his schooling, but stayed on as an assistant teacher. A position at a school in the near-by town of Kendall was offered to Dalton, and after four years in this new job, he became Headmaster of the school... at 19 years of age.

Middle Years

In 1791, Dalton moved to Manchester, and spent the rest of his years there. He lectured at Manchester Academy on the subject of Natural Philosophy (Science), but resigned when he discovered that this position did not allow him to pursue his own scientific interests to the extent he desired. For the next 34 years, John Dalton earnt his living as a private tutor.

Later Years

By 67 years of age, John Dalton was a highly respected scientist, and received a state pension of £150 per annum. Later this was raised to the fairly princely sum of £300. Throughout his life, Dalton dressed simply in the Quaker fashion, and in his later years was a recluse. Dalton was so highly regarded in the scientific field that in 1830, the French Academy of Science honoured him by electing him to be one of its eight foreign associates. When John Dalton died in 1844, one hundred carriages took part in his funeral procession.

So Why is Dalton Important?

Dalton was interested in meteorology, and kept a daily record of Manchester weather from the time he moved there to the time he died. He was:
"concious of the advantages that might acrue to the husbandman, the mariner, and to mankind in general if we were able to predict the state of the weather with tolerable precision" (Dalton's notebook)
This interest in the state of the atmosphere of Earth was probably the cause of his later fascination and experimentation with gases, and the chemical theories based upon these tests.

What was Dalton's Impact on the Field of Chemistry?

Ten years after Dalton's death, the great German chemist Justus von Leibig was asked to assess the impact of Dalton's work on science:
"We who now stand in the presence of the science as it is now constituted, can scarcely conceive how it would have developed itself without this hypothesis (refering to Dalton's atomic theory). All our ideas are so interwoven with the Daltonian Theory, that we cannot transpose ourselves into the time when it did not exist."

The Chemical Work of John Dalton

"All matter is composed of a great number of extremely small particles or atoms... chemical analysis and synthesis are merely the separation of atoms from one another, or their union" (A New System of Chemical Philosophy, Dalton, 1808)
Yes, John Dalton invented Atomic Theory. It is likely that the idea for this spawned from his work with gases. His experiments with gases also led him to form two more chemical laws, the Law of Partial Pressures (behaviour of gaseous mixtures and dissolving of gases into liquids) and the Law of Multiple Proportions (ratios and gas composition). It is needless to say that without Dalton's work and consequent theories, Chemistry as we know it today may not exist.

Source: "Chemistry for Sixth Forms" by A.H. Wooff, D.T. Howarth and R.C. Rendle

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