John Dalton

John Dalton was born in 1766 in Eaglesfield in Cumberland, England where his father was a smallholder and weaver; like Faraday he had a mother who was an exceptionally intelligent woman. Dalton’s first regular job was that of village schoolmaster and his first scientific interest was in meteorology; he was to remain a teacher and to retain his interest in meteorology for the rest of his active life.

In his early days John Dalton was considerably helped by John Gough, a blind amateur scientist and mathematician who gave him some training in mathematics and introduced him to experimental science. In 1793 Dalton moved to Manchester where he was to spend his remaining fifty-one years of his life. This move brought him into contact with the select group of men who had formed the Manchester Literary and Philosophical Society, an institution with which his name came to be closely linked and which he served as Secretary and as President.

Although John Dalton was a devout and conscientious member of the Society of Friends all his life he does not seem to have expressed any notable views on religious questions, nor does he appear to have taken part in any of the social work characteristic, then and now, of Friends. He kept his political, social, intellectual and aesthetic opinions to himself. It seems that he liked music but his colour-blindness, which by a remarkable scientific inquiry he himself diagnosed, must have limited his appreciation of the visual arts. It has even been suggested that his character may have been influenced by his colour-blindness: certainly it is surprising that he never commented on the radical transformation which he must have witnessed when Manchester ceased to be a country town and became a grimy industrial city.

John Dalton never married; teaching, research, religious observance, the well-regulated life of a scholarly bachelor gifted with a mind of great power and insight, were the dominant features of John Dalton’s career. By all accounts he was reserved, quite unaffected and spoke with a marked regional accent. This then was the man who was to leave an indelible impress on physical science and who, in several ways, determined the broad strategy of nineteenth-century chemistry and, to some extent, physics too.

Dalton’s Atomic Theory

The reconstruction of the sequence by which John Dalton was led to formulate his chemical atomic theory has, for more than a century now, provided one of the most tantalizing problems in the history of scientific thought. At a time when chemistry occupied the best minds of the day, in a way rarely paralleled before or since, it was the work of this provincial and stubbornly self-reliant savant that gave the science what has ever since remained its fundamental model of reality. Not unnaturally Dalton and the nature of his achievement were soon the subjects of a lively historical controversy. The rival claim of Bryan and William Higgins, actively supported by Humphry Davy and just as actively opposed by Thomas Thomson, provides the most obvious early instance of this controversy. Allied to this minor but still continuing skirmish over questions of priority are two fascinating and far more fundamental problems.

One, just mentioned above, is the recovery of the actual history of Dalton’s work. The other is closely related and equally demanding. It is to elucidate the historiography of Dalton’s achievement. Although historians may not always advance an understanding of their professed objects of study, their work cannot but cast light upon the values, attitudes, and assumptions of their own time. The changing historiography of chemical atomic theory thus offers insights into the changing utility and prestige of the theory itself. It also offers important clues to the unravelling of Dalton’s own work, and reflects significant shifts in popular philosophies of science and history. Such an apparently esoteric subject may thus repay attention.

In fact the key to the long and confused history of attempts to explain the origins of Dalton’s theory lies in three observations: that Dalton was not primarily, and certainly not initially, a chemist; that the history of science was till very recently the exclusive pursuit of often devoted, but perforce limited, amateurs; and that in the latter part of the nineteenth century Manchester became the home of a flourishing and influential school of chemistry.