Greatest Simplicity Rule

John Dalton

September 6, 1803: British chemist John Dalton writes in his laboratory notebook. He was born in Manchester, England in 1844 and is best known for his work in modern atomic theory as well as research into color blindness. He was born into a Quaker family which limited job opportunities in Britain at the time. Dissenters were not permitted to attend or teach at English universities. He studied under John Gough and using Gough’s influence was given a teaching position at New College in Manchester. He also became interested in meteorology and began keeping a diary where he made over 200,000 observations spanning 57 years.

In 1803, Dalton became the secretary of the Manchester Literary and Philosophical Society (Lit & Phil) and published several articles there. This led him to the study of elements. On this day, he made a list of the relative weights of the atoms of six elements: hydrogen, oxygen, nitrogen, carbon, sulfur, and phosphorus. He assigned hydrogen the number 1 but did not say how he came to this finding. He, like others of the time, was convinced all elements were made of gases. By using chemical analysis of water, ammonia, carbon dioxide, and others, he determined chemical combinations took place between particles in different ways because it would be the simplest way for them to combine. He also began to use his own symbols to visually represent the atomic structure of compounds.

Dalton came up with an atomic theory which had five main points. First, elements were made up of teeny, tiny things called atoms. Second, atoms of a given element are identical to each other and different from other elements in regard to size, mass, and other properties. Third, atoms cannot be subdivided, created, or destroyed. Fourth, atoms of different elements combine in simple whole-number ratios to form chemical compounds. Lastly, chemical reactions show atoms combining, separating, or rearranging. He added, to great controversy, that the “rule of greatest simplicity” that atoms combine in only one ratio, a binary one, but it was an assumption and not proven.

His theory has survived although today we understand that rule number three can be thwarted as seen in nuclear fusion and fission. These are not chemical reactions, but nuclear reactions. The second rule has also been modified to allow for isotopes of elements which have slightly varying weights. Because of his varying interests, he was able to contribute 116 articles/memoirs for Lit & Phil before his death in 1844 at the age of 77. He had suffered two minor strokes, one in 1837 and the second in 1838, which left him with speech impairments but able to continue with his scientific experiments. He suffered a more massive stroke in May 1844 but continued to make his meteorological observations. His last entry was on July 26, written in a trembling hand. He was found dead on July 27, 1844.

It’s the right idea, but not the right time. – John Dalton

This paper will no doubt be found interesting by those who take an interest in it. – John Dalton

If I have succeeded better than many who surrounded me, it has been chiefly – may I say almost solely – from universal assiduity. – John Dalton

John Dalton’s records, carefully preserved for a century, were destroyed during the World War II bombing of Manchester. It is not only the living who are killed in war. – Isaac Asimov

Also on this day: “Simplify, simplify.” – In 1847, Henry David Thoreau leaves Walden Pond.
Around the World in Years – In 1522, the first circumnavigation of the globe finally ends.
Howard Unruh – In 1949, a mass murdering spree in New Jersey took place.
Assassination – In 1901, President William McKinley was shot.