Émile; Or, Concerning Education; Extracts

by Jean-Jacques Rousseau

"What an amount of preparation!" you will say. True; and all to make us a compass to use instead of a meridian line!

Having learned that a magnet acts through other bodies, we were all impatience until we had made an apparatus like the one we had seen,—a hollow table-top with a very shallow basin adjusted upon it and filled with water, a duck rather more carefully made, and so on. Watching this apparatus attentively and often, we finally observed that the duck, when at rest, nearly always turned in the same direction. Following up the experiment by examining this direction, we found it to be from south to north. Nothing more was necessary; our compass was invented, or might as well have been. We had begun to study physics.

Experimental Physics.

The earth has different climates, and these have different temperatures. As we approach the poles the variation of seasons is more perceptible,—all bodies contract with cold and expand with heat. This effect is more readily measured in liquids, and is particularly noticeable in spirituous liquors. This fact suggested the idea of the thermometer. The wind strikes our faces; air is therefore a body, a fluid; we feel it though we cannot see it. Turn a glass vessel upside down in water, and the water will not fill it unless you leave a vent for the air; therefore air is capable of resistance. Sink the glass lower, and the water rises in the air-filled region of the glass, although it does not entirely fill that space. Air is therefore to some extent compressible. A ball filled with compressed air bounds much better than when filled with anything else: air is therefore elastic. When lying at full length in the bath, raise the arm horizontally out of the water, and you feel it burdened by a great weight; air is therefore heavy. Put air in equilibrium with other bodies, and you can measure its weight. From these observations were constructed the barometer, the siphon, the air-gun, and the air-pump. All the laws of statics and hydrostatics were discovered by experiments as simple as these. I would not have my pupil study them in a laboratory of experimental physics. I dislike all that array of machines and instruments. The parade of science is fatal to science itself. All those machines frighten the child; or else their singular forms divide and distract the attention he ought to give to their effects.

I would make all our own machines, and not begin by making the instrument before the experiment has been tried. But after apparently lighting by chance on the experiment, I should by degrees invent instruments for verifying it. These instruments should not be so perfect and exact as our ideas of what they should be and of the operations resulting from them.

For the first lesson in statics, instead of using balances, I put a stick across the back of a chair, and when evenly balanced, measure its two portions. I add weights to each part, sometimes equal, sometimes unequal. Pushing it to or fro as may be necessary, I finally discover that equilibrium results from a reciprocal proportion between the amount of weight and the length of the levers. Thus my little student of physics can rectify balances without having ever seen them.

When we thus learn by ourselves instead of learning from others, our ideas are far more definite and clear. Besides, if our reason is not accustomed to slavish submission to authority, this discovering relations, linking one idea to another, and inventing apparatus, renders us much more ingenious. If, instead, we take everything just as it is given to us, we allow our minds to sink down into indifference; just as a man who always lets his servants dress him and wait on him, and his horses carry him about, loses finally not only the vigor but even the use of his limbs. Boileau boasted that he had taught Racine to rhyme with difficulty. There are many excellent labor-saving methods for studying science; but we are in sore need of one to teach us how to learn them with more effort of our own.

The most manifest value of these slow and laborious researches is, that amid speculative studies they maintain the activity and suppleness of the body, by training the hands to labor, and creating habits useful to any man. So many instruments are invented to aid in our experiments and to supplement the action of our senses, that we neglect to use the senses themselves. If the graphometer measures the size of an angle for us, we need not estimate it ourselves. The eye which measured distances with precision intrusts this work to the chain; the steelyard saves me the trouble of measuring weights by the hand. The more ingenious our apparatus, the more clumsy and awkward do our organs become. If we surround ourselves with instruments, we shall no longer find them within ourselves.

But when, in making the apparatus, we employ the skill and sagacity required in doing without them, we do not lose, but gain. By adding art to nature, we become more ingenious and no less skilful. If, instead of keeping a child at his books, I keep him busy in a workshop, his hands labor to his mind's advantage: while he regards himself only as a workman he is growing into a philosopher. This kind of exercise has other uses, of which I will speak hereafter; and we shall see how philosophic amusements prepare us for the true functions of manhood.

I have already remarked that purely speculative studies are rarely adapted to children, even when approaching the period of youth; but without making them enter very deeply into systematic physics, let all the experiments be connected by some kind of dependence by which the child can arrange them in his mind and recall them at need. For we cannot without something of this sort retain isolated facts or even reasonings long in memory.