Frederick Soddy's productive pure research ended with the outbreak of World War I. Before that time Soddy was internationally acknowledged as a great scientist. He had, with Rutherford, produced the atomic disintegration theory and, in association with Ramsay, had proved it experimentally. He had been one of the first men to elucidate the nature of isotopes, and it was he who gave them their name. After the war he was dismissed as a man who had forsaken his science to propound wild theories of monetary reform.

It is for his scientific achievements that we best remember Frederick Soddy—first as the young chemist working with Ernest Rutherford and with William Ramsay in elaborating the disintegration theory of radioactive change, and then as the mature chemist, heading a research programme of his own at the University of Glasgow, a programme which culminated in his formulation of the concept of isotopes in the years before the First World War. Yet there was another side to Soddy's early scientific career: beyond his profound concern with the purely theoretical and experimental aspects of radioactivity research, there was a serious interest in what might be called the practical significance of his science. By practical, I mean those aspects capable of being put to use for the immediate or potential future benefit of man. In this paper I wish to elucidate the nature of this concern during Soddy's career, focusing particularly upon his years at the University of Glasgow, 1904–1914.

In his presidential address to the chemistry section of the British Association in 1907, Arthur Smithells pointed to work in radioactivity with wonder, calling it the ‘chemistry of phantoms’. Indeed, the transitory nature of the radioelements, coupled with the exceedingly small quantities commonly handled, made many a traditional chemist hesitant to accept these unusual substances as real elements worthy of insertion into the periodic table. Besides, there were too many of them: by 1913 over thirty radioelements were known, but there were no more than twelve boxes in the periodic table in which to house them. Moreover, there was much confusion about radioelements that had different physical properties such as half-life and range of emitted alpha particle, but which could not be separated chemically. Small wonder then that Alexander Russell, the only person who worked with both Ernest Rutherford and Frederick Soddy, recalled the prevalent attitude of chemists as discouraging of interpretative attempts: theirs was, so they claimed, ‘an experimental science. No good ever came from pontificating on the ways of Nature from the comfort of an armchair. The laboratory bench, not the sofa, … was where the truth would be found’.

Frederick Soddy (1877–1956), one of the foremost radiochemists of his day, was awarded the 1921 Nobel Prize in chemistry. Soddy was also among the first of the scientific leaders of his age, along with Blackett (1897–1974), Bernal (1901–71), and others, to become interested in the social implications of their work. In 1950 his colleague Paneth wrote that currently ‘there is widespread discussion on the responsibility towards the community of men of science and particularly experts in radioactivity; but a perusal of Prof. Soddy's non-chemical writings of no less than thirty years ago [viz., during and after the first world war] shows how strongly he felt the duty to fight for a better order of things'. Soddy was a complex iconoclast often derided for dealing with what seemed to be disparate interests. What, it could be asked, could monetary reform possibly have to do with radiochemistry? But to make sense of Soddy, the question must rather be formulated in the other direction: What fundamental concern did Soddy have that enabled him to embrace holistically a variety of seemingly diverse activities? The answer can be given in a word: energy. And the way in which Soddy dealt with this issue involved him directly with social economics as well as with the social responsibility of scientists.