3 Matching Annotations
  1. Dec 2023
    1. Isothermal remanent magnetization

      Although other remanence-acquisition processes commonly occur isothermally (e.g., ARM and CRM), the term IRM is generally understood to involve the application and removal of a significant DC magnetic field, that is, one approaching the coercivity of ferrimagnetic materials (on the order of several millitesla to tens or hundreds of millitesla).

      Such intense fields are rare in natural terrestrial environments, but IRMs can be imparted by lightning strikes

  2. Dec 2019
    1. I may there discover the wondrous power which attracts the needle

      Robert's expedition hopes to reach the magnetic North Pole. Contemporary scientific debates suggested magnetism as the most powerful natural force responsible for life. For a full account of magnetism and electricity in the novel and its offspring, see Iwan Rhys Morus, Frankenstein's Children: Electricity, Exhibition, and Experiment in Early Ninteenth-Century London (Princeton University Press, 1998).

    2. r by ascertaining the secret of the magnet

      We now know that the magnetic charge of the North Pole causes the needle of a compass to point north. However, until William Gilbert (1540-1603) discovered the magnetism of the earth's poles, it was a common conception that the needle on the compass moved by force of magic. In Shelley's time, the source of the earth's magnetism was a mystery and adventurers like Robert Walton set out to the North and South Poles seeking scientific answers and public glory.