An essay on electricity : in which the theory and practice of that useful science, are illustrated by a variety of experiments, arranged in a methodical manner ; to which is added, an essay on magnetism / by George Adams, Mathematical Instrument-Maker to His Majesty.

  • Adams, George, 1750-1795.
Date:
1784
Catalogue details

Licence: Public Domain Mark

Credit: An essay on electricity : in which the theory and practice of that useful science, are illustrated by a variety of experiments, arranged in a methodical manner ; to which is added, an essay on magnetism / by George Adams, Mathematical Instrument-Maker to His Majesty. 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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    proceeding round the magnet to enter the other,, will be impeded, and its velocity leffcned. If tjaey are too Ihort, the fluid which comes out from one pole, will be repelled and thrown back by the other acting parts of the magnet, and thus be carried too far from the pole into which it ought to enter, and prevent the conti- nued circulation of the magnetic matter. If they are too thin, then the number of pores are too few to receive a ftrearrr fufficiently ftrong to fefift the obftacles in the external fpace ; while, I ' if they are too thick, the ftrait and regular di- rection of the channel is injured by the diffi- culty which takes place in the arrangement of the interior channels, as the magnetic matter has not fufficient force to penetrate the flecl to any considerable depth, and thus injures the circu- lation of the fluid. All the pieces fhould be well polilhed; it is of the greater! importance that the ends fhould be flat and true, fo as to touch, in as many points as is poflible, the ends of foft iron which keep up the circulation. Inequalities on the faces, but principally near the poles, are to be avoided, as thefe occafion irregularities in the circulation, and thus diminilh its velocity, which is one of the principal fources of mag- netic power. While the bars are touching, the ends of foft iron mould be kept in conftant contact with' the bars, for a momentary reparation, is fufficient- Z 2 toJ