John Dalton

He did not marry all his life and lived a modest life and socialised with a few friends from the Quaker group.

In 1837, he suffered a stroke and the following year he suffered another one that left him with a speech impediment.

After he suffered a third stroke, at the age of 77, he fell off from his bed and his attendant found him dead when he came to serve him tea. He was laid to rest at the Manchester Town Hall.

John Dalton was born in the small settlement of Eaglesfield in Cumberland, England to Joseph Dalton, a poor weaver and Deborah Greenup, who belonged to a prosperous Quaker family in England.

His family was ‘Quaker’, a member of a Christian Movement, whose ideology was derived from a verse in the New Testament. At the age of 15, he helped his older brother Jonathan run a Quaker school in Kenda, Cumbria.

From 1787, he kept a meteorological diary and through his lifetime he recorded over 20,000 weather observations over a period of 57 years.

Sometime around 1790, he planned to pursue law or medicine but since he was a ‘dissenter’, a member of an organisation that opposed the Church of England, he was not allowed to study at English Universities.

In 1793, he moved to Manchester, where he was appointed as a teacher of mathematics and natural philosophy at the New College, a dissenting academy that provided jobs to religious non-conformists with higher education.

All through his younger days, he looked up to Elihu Robinson, a prominent Quaker and accomplished meteorologist, who had a great influence in inculcating in him an interest for mathematics and meteorology.

In 1793, ‘Meteorological Observations and Essays’, his first book of essays on meteorological topics based on his own set of observations was published. This book laid the foundation for his later discoveries.

In 1794, he authored a paper titled ‘Extraordinary facts relating to the vision of colours’, one of his early works on colour perception of the eye.

In 1800, he gave an oral presentation titled ‘Experimental Essays’, that dealt with information on his experiments on gasses and the study of the nature and chemical makeup of air in relation to atmospheric pressures.

In 1801, he came up with the ‘Dalton Law’ also known as Dalton's Law of Partial Pressures’. This theory is used by scuba divers today to gauge pressure levels at different depths of the ocean and its effect on air and nitrogen levels.

He coined the term ‘Daltonism’, which is a term for colour blindness and it became synonymous with his name. He elaborated on this topic in his 1798 paper titled ‘Extraordinary facts relating to the vision of colours, with observation’.

In his 1808 publication ‘A New System of Chemical Philosophy’, he coined the atomic theory and was the first scientist to prepare a table on atomic weights. This theory is considered valid even today and laid the foundation for further studies in this field.