The Encyclopaedia Britannica, or Dictionary of Arts, Sciences, and General Literature Volume 8, No. 2

The Encyclopaedia Britannica, or Dictionary of Arts, Sciences, and General Literature Volume 8, No. 2

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1842 edition. Excerpt: ...the same size. In this case also he found that the electricity was equally distributed between the two discs; and he obtained the same result by using various other substances, and performing the experiments with a large torsion balance, with globes of five or six inches diameter. In all experiments of this kind, the two balls must be allowed to remain a short time in contact, as several seconds elapse before an imperfectly insulating ball is capable of acquiring from the other half of its electricity. When the experiment is made with circular discs, the surface of the one must be placed symmetrically on the surface of the other. In order to determine whether the electricity pervaded the whole substance of the conductor, or was distributed on its surface, Coulomb provided an electrometer, consisting of a small circle of tinsel, suspended by a fibre of gumlac, which, when suspended in a cylinder of glass, is so extremely sensible that a force equal to the sixty thousandth part of a grain was sufficient to repel the ball of the needle through an arch of more than ninety degrees. The conductor whose electrical state he proposed to examine was a solid cylinder of wood four inches in diameter, and pierced with several holes four lines wide and four deep. This cylinder was then supported upon an insulating stand, and electrified by sparks from a Leyden jar. He then took a small circle of gilt paper one and a half line in diameter, and about the eighteenth part of a line in thickness, and he insulated it at the extremity of a cylinder of gum-lac a line in diameter. Having electrified the tinsel of his electrometer, he brought the circle of gilt paper into contact with the surface of the electrified wooden cylinder, and upon presenting the circle to more

Product details

  • Paperback | 476 pages
  • 189 x 246 x 24mm | 844g
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236612922
  • 9781236612922