Researches on diamagnetism and magne-crystallic action : including the question of diamagnetic polarity / by John Tyndall.

  • Tyndall, John, 1820-1893.
Date:
1870
Catalogue details

Licence: Public Domain Mark

Credit: Researches on diamagnetism and magne-crystallic action : including the question of diamagnetic polarity / by John Tyndall. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

    64/436 (page 38)
    SECOND MEMOIR. ON DIAMAGNETISM AND MAGNE-CKYSTALLIC ACTION. [This investigation was conducted in the laboratory of Professor Magnus, of Berlin, during the spring of 1851, and was communicated to the British Association at its meeting at Ipswich the same year. It was also published in the ' Philosophical Magazine' for Sep- tember, 1851.—J. T. 1870.] § 1. On Diamagnetism. Five years ago Faraday established the existence of the force called diamagnetism, and from that time to the present some of the first minds in Germany, France, and England have been devoted to the investigation of this subject. One of the most important aspects of the inquiry is the relation which subsists between magnetism and diamagnetism. Are the laws which govern both forces identical ? Will the mathematical expres- sion of the attraction in the one case be converted into the ex- pression of the repulsion in the other by a change of sign from positive to negative ? The conclusions arrived at by Plucker in this field of inquiry are exceedingly remarkable and deserving of attention. His first paper, ' On the relation of Magnetism and Diamagnetism,' is* dated from Bonn, September 8, 1847, and will be found in Poggendorff's Annalen and in Taylor's ' Scientific Memoirs.' He sets out with the question, ' Is it possible, by mixing a mag- netic substance with a diamagnetic, so to balance the opposing forces that an indifferent body will be the result ?' This ques- tion he answers in the negative. c The experiments,' he writes, ' which I am about to describe, render it necessary that every thought of the kind should be abandoned.' One of these experiments will serve as a type of the whole, and will show the foundation on which the negative reply of