“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.
CHAPTER XXXVIII
FRANKLIN AND DE ROMAS
THE next day Claire and her two brothers could talk of nothing but the experiments of the evening before. It was their subject of conversation the whole morning. The cat’s beads of fire and the flashes from the paper had greatly impressed them; so their uncle, in order to profit by this awakening of their attention, resumed as soon as possible his instructive talk.
“I am sure you are all three asking yourselves why, before telling you about thunder, I rubbed sealing-wax, a strip of paper, and the cat’s back. You shall know, but first of all listen to a little story.
“More than a century ago a magistrate of the little town of Nérac, named de Romas, devised the most momentous experiment ever registered in the annals of science. One day he was seen going out into the country in a storm, with an enormous paper kite and a ball of twine. Over two hundred persons, keenly interested, accompanied him. What in the world was that celebrated magistrate going to do. Forgetful of his grave functions, did he propose some diversion unworthy of him? Was it to witness a puerile kite-flying that these curious ones flocked from all points of the town? No, no; de Romas was about to realize the most audacious project that man’s genius has ever conceived; his bold purpose was to evoke the thunderbolt from the very depths of the clouds, and to call down fire from heaven.