Natural Philosophy #5 John Dalton’s Eyeball

There is a rather strange story, a true story, about John Dalton, who is known as The Founding Father of Chemistry. It concerns his eyeballs and I’ll come onto them shortly. Dalton is best known for his Atomic Theory, the first scientist to prove from careful experiments that matter was comprised of compounds, made up of elements which in turn were made of atoms.

His results were derived from experiments and observations from his study of meteorology resulting in his Law of Partial Pressures (of gases). In 1803 he was able to state categorically that each element comprised individual atoms that could not be separated further. (In this last part he was incorrect since we now know that atoms comprise electrons, protons and neutrons and can also be “split”). He was awarded the Royal Medal, a prestigious award presented annually by the Royal Society for the most important contributions to the advancement of natural knowledge.


Dalton was born in Cumbria, England, in 1766. His parents were Quakers and he had virtually no formal education (at that time Quakers were not allowed to attend university!) However, through personal studies over several years and his dogged research into meteorology he was recommended for a job as a tutor at Manchester College, subsequently named after him. By the time he arrived in Manchester, Dalton had begun to realise that he saw the world differently from most other people, as he wrote in a letter to one of his mentors:

“I am at present engaged in a very curious investigation. I discovered last summer with certainty, that colours appear different to me to what they do to others except my brother who seems to see as I do.”

Dalton’s observation that he and his brother both shared such an anomaly led him to conclude that his unusual colour perception was the result of a hereditary condition. His account of this phenomenon to the Manchester Literary and Philosophical Society in 1794 is the first recorded description of colour blindness, or as it became known, Daltonism. Over the next few years, Dalton conducted extensive research on his affliction, culminating in the publication of his 1798 paper, ‘Extraordinary facts relating to the vision of colours’, in which he proposed that his own colour blindness was the result of his vitreous humour (the jelly-like part of his eye) possessing an abnormal blue tint, thus acting as a filter for certain wavelengths of light.
And so now we come to the title of my post, John Dalton’s Eyeball, because he had ordered that a post-mortem examination of his eyes should be carried out and so after his death in 1844, it was revealed that their contents were “perfectly colourless.”. But …….. in 1995, modern scientists conducted a DNA analysis of his preserved eyeball, and it was revealed he had what is known today as red-green colour blindness, or deuteranopia: a rare form of the condition caused by a missing gene for the receptor sensitive to medium wavelength (green) light.A very strange story, but John Dalton was another of those extraordinary scientists from that era, a giant to stand alongside Isaac Newton, Robert Boyle, Edmond Halley, Robert Hooke, Michael Faraday ……. they defied previous dogma and narrow mindedness to open the door for modern science to burst through. They were all a product of or created The Enlightenment, often called The Age of Reason and we should be mindful of and thankful for their contribution to modern society.

Categories: Natural Philosophy, Philosophy

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9 replies

  1. it’s not easing going against the standard quo, but that is often where new knowledge comes from; great story about Dalton…

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  2. Great post, Dr. B. Insightful as always. We could use another Age of Reason now in these “interesting” times.

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    • We sure could, we are definitely in an Age of Unreason currently, and I’m willing to bet the farm that these cancellation hypocrites have no idea about the Enlightenment either. I read somewhere recently that a group of ignorant students were even trying to “cancel” Isaac Newton! They have no idea how pathetic they appear …… I’d like to put them in a world where Newton, Boyle, Hooke, Dalton, Faraday etc etc had never existed 🤣

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