The Atomic Weight of Lead of Radioactive Origin: A Confirmation of the Concept of Isotopy and the Group Displacement Laws

Kauffman, George B.

doi:10.1007/978-94-009-5297-3_7

Cited by 4 publications

(2 citation statements)

References 47 publications

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“…A puzzling issue that cropped up during studies on radioactive transformations was that the element lead in different radioactive mineral samples gave different atomic weights and also not the same as lead from nonradioactive sources (Kauffman, 1982). Many workers have used thorite and thorianite samples from Ceylon to elucidate this problem (Soddy & Hyman, 1914;Richards, 1914;Soddy, 1915;Soddy, 1917).…”

Section: Ceylon Thorium Minerals and Atomic Weight Of Leadmentioning

confidence: 99%

Thorium minerals in Sri Lanka, history of radioactivity and thorium as a future energy source: a compendium to commemorate the International Year of Chemistry 2011

Tennakone

2011

J. Natn. Sci. Foundation Sri Lanka

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The discovery of radioactivity more than a century ago and vigorous research on the subject thereafter has transformed the world scientifically and technologically through a deeper understanding of the nature of matter. Two stalwarts among the illustrious pioneers in this field were Lord Ernest Rutherford and Madame Marie Curie. Both were physicists by training and both won the Nobel Prize for Chemistry. While Rutherford's work was more inclined towards physics, enabling elucidation of the structure and mechanics of the atom, Curie's discoveries instantly catalyzed a revolution in chemistry. The year 2011, designated as the International Year of Chemistry, celebrates the centennial anniversary of award of the Chemistry Nobel Prize to Marie Curie. When Marie Curie separated radium from pitchblende, the curious researchers and amateurs started turning stones around looking for pitchblende and other radioactive minerals. In this endeavour, a British planter in Sri Lanka (then Ceylon) collected heavy rock samples, similar in appearance to pitchblende, and dispatched them to two eminent researchers pursuing studies on radioactivity in Britain. Analysis by chemists in Britain and subsequent prospecting by the then Ceylon Geological Survey enabled identification of thorium oxide thorium and silicate minerals, thorianite and thorite, containing a very high percentage of thorium. A number of major discoveries in radioactivity by outstanding pioneers in this field have been conducted using Ceylon thorianite and thorite. Most reputed physics and chemistry journals in the first three decades of the twentieth century carry articles on these discoveries making conspicuous references to Ceylon thorium minerals. The International Year of Chemistry is an appropriate moment to review the history of radioactivity in relation to thorium minerals of Sri Lanka. Coincidently, Sri Lanka and several other countries are currently focussing much attention on the use of thorium as a safe, environmentally benign and lasting source of energy. This work examines discoveries in radioactivity made by pioneers of this field, using Ceylon thorium minerals, giving historical anecdotes on use of Sri Lankan minerals in understanding fundamental properties of matter. The important aspects of uranium-thorium mineral chemistry, formation of radioactive mineral sand placer deposits and generation of thorium based nuclear energy are also discussed, because of current relevance of these topics to Sri Lanka.

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Section: Ceylon Thorium Minerals and Atomic Weight Of Leadmentioning

confidence: 99%

Thorium minerals in Sri Lanka, history of radioactivity and thorium as a future energy source: a compendium to commemorate the International Year of Chemistry 2011

Tennakone

2011

J. Natn. Sci. Foundation Sri Lanka

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“…It is a common theme in science. Robert Strutt claimed that he had thought of how to date minerals before Rutherford did, or certainly before Rutherford published (Egerton 1948), and although Frederick Soddy is credited with the concept of isotopy because he coined the term "isotope' in 1913, the idea of several species of the same by guest on May 11, 2018 http://sp.lyellcollection.org/ Downloaded from element had been around for a decade previously (Kauffman 1982). The process of 'discovery' is in fact rarely a 'Eureka' moment, being almost always one of a gradual evolution of i d e a s -the replication of memes (Dawkins 1989) that occasionally mutate.…”

Section: The Storehouse Of Creationmentioning

confidence: 99%

Celebrating the age of the Earth

Knell

Lewis

2001

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The age of the Earth has been a subject of intellectual interest for many centuries, even millennia. Of the early estimates, Archbishop Ussher’s famous calculation of 4004 bc for the date of Creation represents one of the shortest time periods ever assigned to the Earth’s age, but by the seventeenth century many naturalists were sceptical of such chronologies. In the eighteenth century it was Nature that provided the record for Hutton and others.But not all observers of geology enquired about time. Many, like William Smith, simply earned a living from their practical knowledge of it, although his nephew, John Phillips, was one of the first geologists to attempt a numerical age for the Earth from the depositional rates of sediments. For more than fifty years variations of that method prevailed as geology’s main tool for dating the Earth, while the physicists constrained requirements for a long timescale with ever more rigorous, and declining, estimates of a cooling Sun and Earth.In 1896 the advent of radioactivity provided the means by which the Earth’s age would at last be accurately documented, although it took another sixty years. Since that time ever more sophisticated chronological techniques have contributed to a search for the oldest rocks, the start of life, and human evolution. In the attempt to identify those landmarks, and others, we have greatly progressed our understanding about the processes that shape our planet and the Universe, although in doing so we discover that the now-accepted age of the Earth is but a ‘geochemical accident’ which remains a contentious issue.

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Atomic number and isotopy before nuclear structure: multiple standards and evolving collaboration of chemistry and physics

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2022

Found Chem

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We provide a detailed history of the concepts of atomic number and isotopy before the discovery of protons and neutrons that draws attention to the role of evolving interplays of multiple aims and criteria in chemical and physical research. Focusing on research by Frederick Soddy and Ernest Rutherford, we show that, in the context of differentiating disciplinary projects, the adoption of a complex and shifting concept of elemental identity and the ordering role of the periodic table led to a relatively coherent notion of atomic number. Subsequent attention to valency, still neglected in the secondary literature, and to nuclear charge led to a decoupling of the concepts of elemental identity and weight and allowed for a coherent concept of isotopy. This concept received motivation from empirical investigations on the decomposition series of radioelements and their unstable chemical identity. A new model of chemical order was the result of an ongoing collaboration between chemical and physical research projects with evolving aims and standards. After key concepts were considered resolved and their territories were clarified, chemistry and physics resumed autonomous projects, yet remained bound by newly accepted explanatory relations. It is an episode of scientific collaboration and partial integration without simple, wholesale gestalt switches or chemical revolutions.

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The Atomic Weight of Lead of Radioactive Origin: A Confirmation of the Concept of Isotopy and the Group Displacement Laws

Cited by 4 publications

References 47 publications

Thorium minerals in Sri Lanka, history of radioactivity and thorium as a future energy source: a compendium to commemorate the International Year of Chemistry 2011

Thorium minerals in Sri Lanka, history of radioactivity and thorium as a future energy source: a compendium to commemorate the International Year of Chemistry 2011

Celebrating the age of the Earth

Atomic number and isotopy before nuclear structure: multiple standards and evolving collaboration of chemistry and physics

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