Who is John Dalton and What Did He Discover
John Dalton was born on September 6, 1766 in England. He was the son of a weaver.
His early life was spent in teaching first in schools, then at the college level. He taught grammar, chemistry and mathematics.
He had a very keen scientific mind and he was also self taught.
From the age of 21 and for 57 years after, he kept a Meteorological diary. In 1793 he published the first book called ‘Meteorological observations and essays’.
His study of the weather and atmosphere aroused in him an interest in gases.
In 1802 he formulated the ‘law of partial pressures in gases’. The law states that the total pressure of a confined gas mixture equals the sum of the pressures each gas would exert alone in the same volume.
In 1803 he proposed the theory of atoms which he considered to be the smallest parts of matter. This theory became one of the foundations of chemistry and is Dalton’s most important contribution to science.
Both he and his brother were colour blind. He was the first to study colour blindness which, for a time, was called Daltonism, after him.
He had requested that his eyes be examined after death so that the cause of his colour blindness could be determined.
The experts who examined his eyes on his death in July 1844 could not come to any definite conclusion, but one of his eyes was removed and preserved.
A study of DNA extracted from this eye, in 1990 revealed that he had lacked the pigment that gives sensitivity to green.