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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    to deftroy the effeftof the operation, as the fluid vVill be inftantly difperfed in the air. The Operator ought not to flop longer on the firft bar than is neceflary to open the pores, and to arrange them magnetically, pairing imme- diately to the other, to form an opening for the fluid which ifTues from the firft. It is molt advantageous to turn the bar that is quitted, while the touching magnets are plaeed on the other ; by this means, the ftream that is tobe excited will difpofe the channels of the firft,; and thus render the operation more efficacious; befides, by only turning, one bar at a time, the touching bars need never be totally removed during the whole operation, acircumftance which will contribute to the ftrength of the magnet. The touching bars fhould never be feparated but at the equator of the magnet; and their mo- tion over the others, fhould be flow and regular. The magnetic power of touched needles has been encreafed by leaving them for fome time in linfeed oiL It may contribute to the effe&s of the ope- ration if the bars A and B, fig. 100, are placed in the direction of the magnetic meridian,, and are inclined to the horizon in an angle equal to the dip of the needle. The fixed power, thus communicated to a magnet, is ihaipaired if it is laid amongft iron, or by ruft; it may be injured alfo by fire, as each of thefe circumftances will change, or c6nfufe the direction of the magnetic ftream. Place