CHAPTER XI
ALL BY ELECTRICITY.
"Sir," said Captain Nemo, showing me the instruments hanging on the walls of his room, "here are the contrivances required for the navigation of the Nautilus. Here, as in the drawing-room, I have them always under my eyes, and they indicate my position and exact direction in the middle of the ocean. Some are known to you, such as the thermometer, which gives the internal temperature of the Nautilus; the baromter, which indicates the weight of the air and foretells the changes of the weather; the hygrometer, which marks the dryness of the atmosphere; the storm-glass, the contents of which, by decomposing, announce the approach of tempests; the compass, which guides my course; the sextant, which shows the latitude by the altitude of the sun; chronometers, by which I calculate the longitude; and glasses for day and night, which I use to examine the points of the horizon when the Nautilus rises to the surface of the waves."
"These are the usual nautical instruments," I replied, "and I know the use of them. But these others, no doubt, answer to the particular requirements of the Nautilus. This dial with the movable needle is a manometer, is it not?"
"It is actually a manometer. But by communication with the water, whose external pressure it indicates, it gives our depth at the same time."
"And these other instruments, the use of which I can not guess?"
"Here, professor, I ought to give you some explanations. Will you be kind enough to listen to me?" He was silent for a few moments, then he said: "There is a powerful agent, obedient, rapid, easy, which conforms to every use, and reigns supreme on board my vessel. Everything is done by means of it. It lights it, warms it, and is the soul of my mechanical apparatus. This agent is electricity."
"Electricity?" I cried in surprise.
"Yes, sir."
"Nevertheless, captain, you possess an extreme rapidity of movement, which does not agree well with the power of electricity. Until now its dynamic force has remained un-
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