John Tyndall and the Early History of Diamagnetism

Abstract

Summary John Tyndall, Irish-born natural philosopher, completed his PhD at the University of Marburg in 1850 while starting his first substantial period of research into the phenomenon of diamagnetism. This paper provides a detailed analysis and evaluation of his contribution to the understanding of magnetism and of the impact of this work on establishing his own career and reputation; it was instrumental in his election as a Fellow of the Royal Society in 1852 and as Professor of Natural Philosophy at the Royal Institution in 1853. Tyndall's interactions and relationships with Michael Faraday, William Thomson, Julius Plücker and others are explored, alongside his contributions to experimental practice and to emerging theory. Tyndall's approach, challenging Faraday's developing field theory with a model of diamagnetic polarity and the effect of magnetic forces acting in couples, was based on his belief in the importance of underlying molecular structure, an idea which suffused his later work, for example in relation to the study of glaciers and to the interaction of substances with radiant heat.

Eunice Foote, John Tyndall and a question of priority

“…He had access to the latest apparatus, and to the skilled instrument-makers who could produce accurate equipment to his specifications. Tyndall had already made a name for himself in his work on diamagnetism 9 and on the structure and motion of glaciers. 10 Several strands of thought drove him now to explore the absorption of heat by gases, including his experiences in the Alps.…”

Modulation of the Magnetic Properties of Aqueous Metal Ions and the Bioelectrodynamic Effects on Cancerous and Noncancerous Cells

“…74 Chloride and copper's atomic structures lend them to the classification of diamagnetic metals. 71 Diamagnetism is a very weak magnetism that is nonpermanent and persists only when an external magnetic field is being produced. These metals create an induced magnetic field in a direction opposite to an externally applied magnetic field and are actually repelled by the magnetic field.…”

“…These metals create an induced magnetic field in a direction opposite to an externally applied magnetic field and are actually repelled by the magnetic field. 71 Molybdenum and sodium are paramagnetic metals, which are attracted by an externally applied magnetic field and form a magnetic field in the same direction of the magnetic field and the strength of this magnetism is in proportion to the applied field. Both diamagnetic and paramagnetic metals are considered to be nonmagnetic, because they only display magnetism when in the presence of an external field.…”

“…Both diamagnetic and paramagnetic metals are considered to be nonmagnetic, because they only display magnetism when in the presence of an external field. 71,76 Nickel is a ferromagnetic metal, which continues to display a permanent magnetism with or without a presence of a magnetic field. Magnets are an example of ferromagnetism because they retain their magnetic properties.…”

“…Ferromagnetic effects are very large and are considered the strongest form of magnetism and often produce magnetism of greater magnitude than an applied field. 71,76 Chromium is one of the few (2) known anti-ferromagnetic metals in our periodic table. In antiferromagnetic materials, the magnetic dipole moments (behaves like tiny magnets) of atoms align in opposing directions of the ordered magnetism of ferromagnetic atoms.…”