An essay on magnetic attractions, and on the laws of terrestrial and electro magnetism : comprising a popular course of curious and interesting experiments on the latter subject, and an easy experimental method of correcting the local attraction of vessels on the compass in all parts of the world : with an appendix, containing the results of experiments made on ship board from latitude 61o S. to latitude 80o N. / by Peter Barlow.

  • Barlow, Peter, 1776-1862.
Date:
1824
Catalogue details

Licence: Public Domain Mark

Credit: An essay on magnetic attractions, and on the laws of terrestrial and electro magnetism : comprising a popular course of curious and interesting experiments on the latter subject, and an easy experimental method of correcting the local attraction of vessels on the compass in all parts of the world : with an appendix, containing the results of experiments made on ship board from latitude 61o S. to latitude 80o N. / by Peter Barlow. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    had drawn from them, as far as related to the incli- nation and direction of the plane of no attraction. Being thus assured that there are in every ball of iron two planes, in which the compass may be any where posited, without being influenced in its direc- tion ; the one that of no attraction, as stated above, and the other the vertical plane, corresponding to the magnetic meridian; my next object was to ascer- tain how far the angle of deviation of the needle was influenced, and what law that deviation observed when the compass was removed out of those planes. But before I proceed to describe the experiments performed with a view to this determination, it may not be amiss to examine the deductions already made, which may be stated as follows : — 8. In the first place, it has been shown that every iron ball has what (from analogy to the case of terrestrial magnetism) may for the present be deno- minated a magnetic equator, lying in the plane of no attraction, above mentioned. 9. That like the earth, also, it may be supposed to have two magnetic poles; the one directed towards the north, and the other towards the south; the line joining those poles being parallel to the natural magnetic direction of the dipping needle. 10. These experiments likewise seem to indicate that the eff*ect produced upon the needle by the iron, (the distance being the same,) depends entirely