Handbook to the Special Loan Collection of Scientific Apparatus 1876

Handbook to the Special Loan Collection of Scientific Apparatus 1876

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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. 1876 edition. Excerpt: ... and by Dal Negro) almost immediately after the announcement by Faraday of his discovery of magneto-electric induction, that is to say, of the production of an electric current in a conductor forming a closed circuit, when an alteration takes place in the total magnetic force acting through the area bounded by the circuit. It is evident that such an alteration can be produced in either of two ways, namely (1), by a change in the magnetic force itself, or (2), by a change in the shape or position of the circuit. The first is the principle applied in the induction coil, and in some magneto-electric machines, including that of Pixii; the second is that on which the action of most magnetoelectric machines chiefly depends, though in many of them the two principles are applied conjointly. The first step in the modern improvements of these machines was the introduction by Siemens and Halske (1857) of an arrangement of the " armature" (a piece of soft iron wound with insulated copper wire, by the movement of which between the poles of a magnet the variations of magnetic force acting across the circuit are produced) whereby nearly the whole force of a large number of steel magnets could be utilised. In 1866 Wilde showed that enormously increased effects could be obtained by causing a Siemens's armature to revolve between the poles of a large electro-magnet, the magnetism of which was developed by the current of a smaller machine provided with permanent steel magnets. In the same year, S. A. Varley, and in the following year, Siemens and Wheatstone almost simultaneously constructed machines in which permanent magnets were entirely dispensed with, and the current caused by a very feebly magnetized electro-magnet was made to strengthen the...show more

Product details

  • Paperback | 116 pages
  • 189 x 246 x 6mm | 222g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236490053
  • 9781236490056