An Essay on Magnetic Attractions, and on the Laws of Terrestrial and Electro Magnetism; Comprising a Popular Course of Curious and Interesting Experi

An Essay on Magnetic Attractions, and on the Laws of Terrestrial and Electro Magnetism; Comprising a Popular Course of Curious and Interesting Experi

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1824 edition. Excerpt: ...of the conclusion I am desirous of drawing from the above tabulated experiments; I have given, in (fig. l6) a delineation to scale of the position of the needle n.9, in respect to the ball N S in each of the situations noted in the preceding table; by which it will be seen how closely the south end, s, of the needle approached (in its position lat. 90) what has been-called the north pole of the ball; consequently, the acceleration of the needle ought, in this position, to have been much greater than we have found it; had the action taken place between N and s, or if N were a condensed centre of action, such as the hypothesis in question supposes. Whereas by referring the whole to a compound central action, we find the most accurate agreement between the observed and computed intensities. _ 190. I am the more anxious to establish this point, in consequence of its immediate connection with the method I have proposed for correcting the errors of a ship's compass, which has been objected to, on the ground that according to the theory we have been controverting, the central action of all the iron on board would not remain constant under all dips and in all parts of the world; but if the hypothesis I have advanced be correct, then the central action of any irregular mass of iron will be in the centre of attraction of its surface, whatever may be the magnetic direction, and must necessarily remain the same, while the iron and the point from which its action is estimated preserve the same relative situation; as is the case with the iron of a vessel and its compass, at least, with the exception of those small changes of position which may, for the sake of convenience, take place in the course of the voyage; but these will never materially...show more

Product details

  • Paperback | 70 pages
  • 189 x 246 x 4mm | 141g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236886925
  • 9781236886927