The Discovery of Induced Electric Currents: Memoirs, by Michael FaradayJoseph Sweetman Ames American book Company, 1900 |
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American Book Company angular velocity appears Arago's arrangement axis battery contact Botany breaking contact bright spark chemical decomposition circuit coil conducting power conductor connected contact was broken contrary direction copper plate copper wire current of electricity dipping needle discharge duced edge effect elec electric current electro-magnet electro-tonic electromotor endless wire exerted experiments Faraday galva galvanom galvanometer needle galvanometer wire Gray's helices ignited inch in diameter induced current induction of electrical inductive action inductive effect inductive force interposed iron cylinder iron helix laboratory latter length long wire magnetic contact magnetic curves magnetic forces magnetic pole Magneto-Electric Induction marked pole mercury metal MICHAEL FARADAY motion moving needle was deflected obtained opposite direction ordinary magnetic pairs of plates particles passed peculiar phenomena position produced rent revolved rotation round second wire sensible short wire soft iron tact text-book tion tricity vibrations voltaic current whilst YORK American zinc
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90. lappuse - I was a very lively, imaginative person, and could believe in the Arabian Nights as easily as in the Encyclopaedia ; but facts were important to me and saved me. I could trust a fact, and always cross-examined an assertion. So when I questioned Mrs.
42. lappuse - The magnet was then revolved by a piece of string passed round it, and the galvanometer-needle immediately indicated a powerful current of electricity. On reversing the order of rotation, the electrical current was reversed. The direction of the electricity was the same as if the copper cylinder (219) or a copper wire had revolved round the fixed magnet in the same direction as that which the magnet itself had followed. Thus a singular independence of the magnetism and the bar in which it resides...
27. lappuse - ... retained by the hand in contact with the amalgamated edge of the disc at the part immediately between the magnetic poles. Under these circumstances all was quiescent, and the galvanometer exhibited no effect. But the instant the plate moved, the galvanometer was influenced, and by revolving the plate quickly the needle could be deflected 90° or more. 89. It was difficult under the circumstances to make the contact between the conductor and the edge of the revolving disc uniformly good and extensive...
12. lappuse - ... but though the contact was continued, the effect was not permanent, for the needle soon came to rest in its natural position, as if quite indifferent to the attached electro-magnetic arrangement. Upon breaking the contact with the battery, the needle was again powerfully deflected, but in the contrary direction to that induced in the first instance.
6. lappuse - Ampere's beautiful theory were adopted, or any other, or whatever reservation were mentally made, still it appeared very extraordinary, that, as every electric current was accompanied by a corresponding intensity of magnetic action at right angles to the current, good conductors of electricity, when placed within the sphere of this action, should not have any current induced through them, or some sensible effect produced equivalent in force to such a current. 4. These considerations, with their consequence,...
21. lappuse - Whilst the wire is subject to either volta-electric or magneto-electric induction, it appears to be in a peculiar state ; for it resists the formation of an electrical current in it, whereas, if in its common condition, such a current would be produced ; and when left uninfluenced it has the power of originating a current, a power which the wire does not possess under common circumstances.
15. lappuse - But as it might be supposed that in all the preceding experiments of this section, it was by some peculiar effect taking place during the formation of the magnet, and not by its mere virtual approximation, that the momentary induced current was excited, the following experiment was made. All the similar ends of the compound hollow helix (34.) were bound together by copper wire, forming two general terminations, and these were connected with the galvanometer. The soft iron cylinder (34.) was removed,...
37. lappuse - ... opposite directions at the same time; their action 'then combined to affect the galvanometer: but all the results were reducible to those above described. 179. The longer the extent of the moving wire, and the greater the space through which it' moves, the greater is the effect upon the galvanometer. 180. The facility with which electric currents are produced in metals when moving under the influence of magnets, suggests that henceforth precautions should always be taken, in experiments upon...
6. lappuse - About twenty-six feet of copper wire one twentieth of an inch in diameter were wound round a cylinder of wood as a helix, the different spires of which were prevented from touching by a thin interposed twine. This helix was covered with calico, and then a second wire applied in the same manner. In this way twelve helices were superposed, each containing an average length of wire of twenty-seven feet, and all in the same direction. The first, third, fifth, seventh, ninth, and...
69. lappuse - Thus the different effects of short wires, long wires, helices, and electro-magnets (1069.) may be comprehended. If the inductive action of a wire a foot long upon a collateral wire also a foot in length, be observed, it will be found very small ; but if the same current be sent through a wire fifty feet long, it will induce in a neighbouring wire of fifty feet a far more powerful current at the moment of making or breaking contact, each successive foot of wire adding to the sum of action ; and by...