The invisible powers of nature / by E.M. Caillard.

  • Caillard, Emma Marie, 1852-1927
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: The invisible powers of nature / by E.M. Caillard. 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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    When an electric current is required, the most ordinary way of producing it is by means of some kind of voltaic battery, but you must not suppose it is the only way. In the next chapter you will hear of a quite different and most important one; and there are others which, though I cannot tell you about them here, are all most interesting and necessary to understand. In the meantime I want to tell you something about electric currents themselves. In the first place, they can flow in any shape. You may have an electric current running along a straight wire, or you may have it flowing along one twisted into a hundred or a thousand coils. The coils do not stop its progress. They affect it in another way, however; they make it very much stronger to attract or repel, for flowing electricity, like electricity at rest, has the power of attracting and repelling. A current of electricity flowing in one direction (from north to south, let us say) attracts a current flowing in the same direction; but it repels one flowing in the o]yposite direction, i.e. from south to north. We know this, not of course by seeing the electric currents, for electricity is never seen, but by observing how wires placed side by side, though not touching each other, behave when