John Dalton (1766-1844) Quaker and physicist

John Dalton could not see the world like most of us: “I have often seriously asked a person whether a flower was blue or pink, but was generally considered to be in jest,” he says in one of the many notes he made on the colour blindness he suffered from, a condition that intrigued him and to which he devoted many hours of study throughout his life. Even so, his vision problems did not prevent him from understanding reality beyond the visible: he found time to become a meticulous meteorologist and a renowned physicist and chemist, and to postulate the first atomic theory in history.