The Story-Book of Science Chapter 37


“SINCE the cat threatens to get cross, we will have recourse to another way of producing electricity.

“You fold lengthwise a good sheet of ordinary paper; then take hold of the double strip by each end. Next, you heat it just to the scorching point over a stove or in front of a hot fire. The greater the heat, the more electricity will be developed. Finally, still holding the strip by the ends alone, you rub it quickly, as soon as it is hot, on a piece of woolen cloth previously warmed and stretched over the knee. It can be rubbed on the trousers if they are woolen. The friction must be rapid and lengthwise of the paper. After a short rubbing the band is quickly raised with one hand, with great care not to let the paper touch against anything; if it did the electricity would be dissipated. Then without delay you bring up the knuckles of your free hand, or, better, the end of a key, near to the middle of the strip of paper; and you will see a bright spark dart from the paper to the key with a slight crackling. To get another spark you must go through the same operations again, for at the approach of the finger or key the sheet of paper loses all its electricity.

“Instead of making a spark, you can hold the electrified sheet flat above little pieces of paper, straw, or feathers. These light bodies are attracted and repelled in turn; they come and go rapidly from the electrified strip to the object which serves them as support, and from this to the strip.”

Adding example to precept, Uncle Paul took a sheet of paper, folded it in a strip to give it more resistance, warmed it, rubbed it on his knee, and finally made a spark fly from it on the approach of his finger-joint. The children were full of wonder at the lightning that sprang from the paper with a crackle. The cat’s beads were more numerous, but less strong and brilliant.

They say that Mother Ambroisine had much trouble that evening in getting Jules to go to bed; for, once master of the process, he did not tire of warming and rubbing. His uncle’s intervention was necessary to put an end to the electric experiments.

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