Originally posted by sebosfato
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relate to this:
Du Faye & Franklin.
It was in the year 1746 that he first began to pay attention to the experiments in electricity which were being made in England and France. A great deal had been learnt about this science since the time when Otto Guericke made the first electrical machine in 1672, and a Frenchman named Du Faye had shown that two different kinds of electricity could be produced by rubbing different substances. You will remember that a pith-ball, when charged with electricity from a stick of electrified sealing-wax, draws back, and will not approach the sealing-wax again (see p.122). But Du Faye discovered that if you rub the end of a glass rod with silk, and bring it near to this ball, it will draw the ball towards itself, showing that the electricity in
the glass rod has exactly the opposite effect to that in the sealing-wax. In other words, while Guericke had shown that substances charged with the same kind of electricity repel each other, Du Faye showed that substances charged with different kinds of electricity attract each other. Both these men thought that electricity was a fluid which was created by the rubbing, and which was not in bodies at other times ; when Franklin, however, began to make his experiments, he came to the conclusion that this was not as they had supposed, but that all bodies have more or less electricity in them, which the rubbing only brings out.
You will now, I think, be able to follow Franklin's experiments. He put a person, whom we will call A, upon a glass stool, and made him rub the glass cylinder of an electrical machine with one hand and place his other hand upon it to receive the electricity. Now, he said, if electricity is created by the rubbing, this person must be filled with it, for he will be constantly taking it from the machine, and it cannot pass away, because of the glass legs under the stool. But he found that A had no more electricity in him after rubbing the cylinder than he had before, neither could any sparks be drawn out of him. He then took two people, A and B, and placing each of them on a glass stool, made A rub the cylinder, and B touch it, so as to receive the electricity. Now notice carefully what happened. B was soon so full of electricity that when Franklin touched him, sparks came out at all points ; but what was still more curious, when Franklin went to A and touched him, sparks came out between them just as they had done between him and B.
This he explained as follows :'A, B, and myself,' he said, have all our natural quantity of electricity. Now when A rubbed the tube, he gave up some of his electricity to it, and this B took, so that A had lost half his electricity and B had more than his share. I then touched B, and his extra charge of electricity passed into me and ran away into the earth. I now went to A, and I had more electricity in me than he had, because he had lost half his natural quantity, and so part of my electricity passed into him, producing the sparks as before.
the glass rod has exactly the opposite effect to that in the sealing-wax. In other words, while Guericke had shown that substances charged with the same kind of electricity repel each other, Du Faye showed that substances charged with different kinds of electricity attract each other. Both these men thought that electricity was a fluid which was created by the rubbing, and which was not in bodies at other times ; when Franklin, however, began to make his experiments, he came to the conclusion that this was not as they had supposed, but that all bodies have more or less electricity in them, which the rubbing only brings out.
You will now, I think, be able to follow Franklin's experiments. He put a person, whom we will call A, upon a glass stool, and made him rub the glass cylinder of an electrical machine with one hand and place his other hand upon it to receive the electricity. Now, he said, if electricity is created by the rubbing, this person must be filled with it, for he will be constantly taking it from the machine, and it cannot pass away, because of the glass legs under the stool. But he found that A had no more electricity in him after rubbing the cylinder than he had before, neither could any sparks be drawn out of him. He then took two people, A and B, and placing each of them on a glass stool, made A rub the cylinder, and B touch it, so as to receive the electricity. Now notice carefully what happened. B was soon so full of electricity that when Franklin touched him, sparks came out at all points ; but what was still more curious, when Franklin went to A and touched him, sparks came out between them just as they had done between him and B.
This he explained as follows :'A, B, and myself,' he said, have all our natural quantity of electricity. Now when A rubbed the tube, he gave up some of his electricity to it, and this B took, so that A had lost half his electricity and B had more than his share. I then touched B, and his extra charge of electricity passed into me and ran away into the earth. I now went to A, and I had more electricity in me than he had, because he had lost half his natural quantity, and so part of my electricity passed into him, producing the sparks as before.
Originally posted by sebosfato
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Séparation ionique fluide mouvement Marc C
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