The immortal chemist John Dalton (1766-44) was pivotal in elucidating the theory of modern atomic theory. However, the idea of atoms can be traced back to the Greeks of antiquity, particularly Democritus (c460BC-c370BC). Aristotle later rejected these ideas, confirming what I once read about Aristotle written by a famous historian of Science: “Aristotle, no other man got so many things wrong”. In fact, during a History of Science Summer School that I delivered at Oxford University, this is one of my essay titles, which my students adore is “Aristotle, no other man got so many things wrong-Discuss”.
Daltonism in Color Blindness Research
Dalton’s Scientific contributions began soon after he took a teaching job in Manchester. He was elected a member of the Manchester Literary and Philosophical Society and promptly published a study on colour blindness, the first scientific paper on the subject. These studies led to this area of research being called Daltonism and who along with James Clerk Maxwell (1831-79) were two “Giants” who suffered from this. Maxwell by the way was the first Physicist to unify two of the four fundamental forces of nature (electricity and magnetism). As a matter of interest one can arrive at the so-called Maxwell equations when one considers the motion of an electron using relativity.
Discoveries in Meteorology
Dalton was also passionate about meteorology, keeping detailed weather records daily from 1787 until he died in 1844. His careful study of the atmosphere led him to conclude that air is a mixture of various gases that exert pressure. Other “Giants” interested in studying meteorology include R. Descartes (1596-50) looking at his Discourse. Still, with a twist of fate here, Aristotle can redeem himself as he was one of the first of the “Giants” to attempt to understand meteorology.
From Atoms to Mountain Heights
Dalton also deduced that different elements have atoms of different sizes and masses—this was quite a deviation from the traditional views of the Greeks. He also proposed that chemistry involves the combination of indivisible atoms in simple, whole-number ratios to make chemical compounds. His atomic theory had flaws, yet it preceded direct evidence of atoms by about a century.
Perhaps another not-so-well-known fact about Dalton was that he predicted the heights of mountains using variations in pressure with height using a barometer.
Valuable Lesson from My Chemistry Teacher
I recall once being chastised by my A-level Chemistry teacher as a 17-year-old boy when I was advised of Dalton’s law of partial pressure, i.e., that the total pressure of a mixture of gases is equal to the sum of the partial forces of each constituent gas. The partial pressure is defined as the pressure each gas would exert if it alone occupied the volume of the mixture at the same temperature. I said, “Well, that is a bit obvious,” only for my teacher to growl at me. “So why didn’t you state it first, then?”
Alas, I have run out of space again.
