John Dalton Biography

John Dalton is best known a the scientist who proposed the revolutionary atomic theory that changed the perception of chemistry and modern-day quantum physics. Scientist John Dalton is also known for his study on colour blindness, he was the first scientist to extensively study this phenomenon. Often time to pay tribute to his work the study of colour blindness is referred to a Daltonism. Apart from explaining the genetic basis of the disease and explaining the structure of the atom, he also gave the concept of Dalton’s Law of Partial Pressures.

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Image: An Illustration of John Dalton

Early Life and Career of Scientist John Dalton

John Dalton one of the most prominent names in the field of chemistry was born on September 6, 1766, in Eaglesfield, England. He was born into a family of Quakers, the term is used to define the historically Protestant Christian set of denominations who are formally known as the Religious Society of Friends. He was born into a modest family, his father was a handloom weaver. Since he was born into a poor family the education seemed like a dream far from reality, determined to have a formal education Dalton was enrolled in the quaker school in his home town. Dalton had two siblings and not much is known about his mother.

At the quaker school, Dalton did exceptionally well, so much so that at the age of 14, he started teaching in the same school. Due to the economic strain on the family, Dalton also worked on a farm but he returned to teaching when he was offered the position of boarding assistant in a school in Kendal. He was soon promoted to the position of headmaster in the Quaker boarding school. He served in the school till 1793. He then joined the New College in Manchester as the tutor of subjects like maths and philosophy. He was 27 years old when he was given the post.

According to John Dalton biography, during his term in the New College in Manchester, he joined a club called Manchester Literary and Philosophical Society. It was this society that gave Dalton full permission to access the library of the university. It was in this university that John Dalton first established his interest in meteorology, although he was famous for his work on Dalton theory of atomic structure and the basis of colour blindness.

John Dalton discovery based on the meteorological events that were based on the velocity and barometric pressure of the wind was first published within a year during his term at the New College of Manchester. John Dalton’s discovery was published in his first book, Meteorological Findings. Prior to the publication of the Dalton theory, he made his name in the scientific community by his findings and hypothesis on subjects like meteorology and colour blindness. 

Dalton was forced to leave the college due to the financial conditions of the college although he never left teaching or experimenting, the Joh Dalton biography documents that after leaving the college, the young scientist continued teaching as a private tutor, he taught subjects like mathematics and philosophy.

John Dalton Information - Early Scientific Works

• Meteorology

Although the scientist is prominently known for the discovery of the atomic structure of the molecule during his early days he was interested in the study of meteorology, he also published some works of research and findings but it did not gain much recognition in the scientific society.

His interest was established in the field at an early age when he was studying at the Quaker school in his hometown. Elihu Robinson, a competent meteorologist had a great impact on the research of John Dalton, he was a meteorologist in the hometown of Dalton, Eaglesfield, Cumbria.

Dalton became increasingly interested in the topic while serving as a principal in the Quaker school of Kendal. During this time he answered mathematical and meteorological questions in two journals named  The Ladies' Diary and the Gentleman's Diary.

Dalton rediscovered the wok of George Hadley's theory of atmospheric circulation, known as Hadley’s cell. He then published his works while tutoring in Manchester College, his works were published as the Meteorological Observations and Essays, which bore the roots of several of his later discoveries He also published his second work unrelated to meteorology under the name of Elements of English Grammar, which was published in 1801.

• Colour Blindness

One of the greatest John Dalton discoveries includes the finding of the genetic basis of colour blindness, although after years of research and development of better generic markers and molecular biology techniques the mutation and translational loss have been discovered the genetic basis of the disease was explained much before by the extraordinary scientist. One of the extraordinary facts about his work on colour blindness was the intricate details and extensiveness of the research methodologies of the experiment. In 1794 he published the findings of the research in the paper called  "Extraordinary facts relating to the vision of colours", the experimental conclusion postulated that the shortage in colour perception was caused by discolouration of the liquid medium of the eyeball, since his brother and he himself was colour blind, he concluded that the loss of colour perception was due to the lack of the cells of the eye. Years it was proved that Dalton suffered from a rare variation of colour blindness which occurred due to the deletion mutation of the gene, the scientific term is deuteranopia, while the common type of colour blindness occurs due to loss of function mutation in one of the alleles of the gene, the term used to define this condition is deuteranomaly. Due to his contribution to the discovery and study of the disease colour blindness is also known as Daltonism.

Dalton’s Law of Partial Pressure

It was during 1800, Joh Dalton became the secretary of the Manchester Literary and Philosophical Society, around this time he made observations related to the different pressure of the atmosphere. He was actually studying the nature and chemical makeup of air in the early 1800s, it was during this he discovered that it was a mechanical system composed of small individual particles that used pressure applied by each gas independently rather than the chemical solvents as believed by many of his contemporaries.

It was in the early 1800s he presented a series of papers "Experimental Essays"  that established his work on the constitution of mixed gases; the pressure of steam and other vapours at different temperatures in a vacuum and in air. He also presented his works on evaporation, and on the thermal expansion of gases. He published his work on the following topics in the four essays, presented between 2 and 30 October 1801. These essays were later published in the Memoirs of the Literary and Philosophical Society of Manchester in 1802.

It was these initial works on the nature and composition of the air that led to the Joh Dalton discovery that the total pressure of a mixture of gases is attributed to the sum of the partial pressures exerted by that of each individual gas while occupying the same space. The theory was later known as Dalton’s Law of Partial Pressure.

Although some of his contemporaries were sceptical of the law, and indeed the law is only applicable to the ideal gases and not in cases of the real gases. but till this day it holds true and serves as principal of working of many hydraulic instruments, one of the most common and important examples of the application of the law is seen in the case of scuba divers who used to gauge how pressure levels at different depths of the ocean will affect the air and nitrogen in their tanks. 

In the 1800s he also postulated the law of thermal expansion, this gave him international recognition by the scientific community. The law explained the heating and cooling reaction of gases under the expansion and compression phenomenon. He illustrated his hypothesis using a dew-point hygrometer which determines the impact of temperature at the level of atmospheric water vapour.

Dalton Atomic Theory

The most prominent John Dalton Discovery is the hypothesis of the atomic structure of the atom. It was this discovery that changed the direction of the study of atom and atomic forces. His initial works in the field were related to atomic weight. In Manchester Literary and Philosophical Society in 1803, Dalton created the first chart of atomic weights. His approach to unfold the structure and forces of atoms were based on the relative weight of the atom. Based on his observation and studies he postulated Dalton theory of atomic structure that explained that the elements are made of extremely small particles called atoms which are not further divisible. The atoms of the same element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties. This was published in a book called  A New System of Chemical Philosophy, which was published in 1808.

Following his work, he later expanded his observations by publishing an appendix to A New System of Chemical Philosophy in 1810. This appendix constituted the details of his experiments, additionally, the appendix also contained the atomic weight of the different elements known at that time.

John Dalton discovery got recognition and was accepted widely by the scientific community, his work was further experimentally proved by the work of Avagadro, who further explained the differences in the atoms and compound atoms. Rajkumari Williamson Jones, a science historian at the University of Manchester Institute of Science and Technology mentions the discovery of Dalton as a crucial point of chemistry.

Death and Legacy

John Dalton never married, although he remained close friends with the members of the Quaker school. He died on July 26, 1844, at his home in Manchester, England, he died because of a stroke. His funeral was attended by 4000 people, he had a civic funeral and was granted full honours.

John Dalton worked as a president of the Manchester Literary and Philosophical Society. He got an honorary degree in Doctorate of Science degree from the prestigious Oxford University. He also received an honorary degree from Edinburgh University in 1834 in Doctorate of Law. He refused his membership in the Royal Science Academy, mainly because of his Quaker beliefs. He continued teaching throughout his life.