Page:A Treatise on Electricity and Magnetism - Volume 1.djvu/70

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Electrification by Friction.

27.] Experiment I[1]. Let a piece of glass and a piece of resin, neither of which exhibits any electrical properties, be rubbed together and left with the rubbed surfaces in contact. They will still exhibit no electrical properties. Let them be separated. They will now attract each other.

If a second piece of glass be rubbed with a second piece of resin, and if the pieces be then separated and suspended in the neighbourhood of the former pieces of glass and resin, it may be observed—

  1. That the two pieces of glass repel each other.
  2. That each piece of glass attracts each piece of resin.
  3. That the two pieces of resin repel each other.

These phenomena of attraction and repulsion are called Electrical phenomena, and the bodies which exhibit them are said to be electrified, or to be charged with electricity

Bodies may be electrified in many other ways, as well as by friction.

The electrical properties of the two pieces of glass are similar to each other but opposite to those of the two pieces of resin, the glass attracts what the resin repels and repels what the resin attracts.

  1. See Sir W. Thomson 'On the Mathematical Theory of Electricity,' Cambridge and Dublin Mathematical Journal, March, 1848