JEAN JACQUES. My dear Emile, what shall we do get out?
EMILE. I am sure I do not know. I am tired, I am hungry, I am thirsty. I cannot go any further.
JEAN JACQUES. Do you suppose I am any better off? I would cry too if I could make my breakfast off tears. Crying is no use, we must look about us. Let us see your watch; what time is it?
EMILE. It is noon and I am so hungry!
JEAN JACQUES. Just so; it is noon and I am so hungry too.
EMILE. You must be very hungry indeed.
JEAN JACQUES. Unluckily my dinner won't come to find me. It is twelve o'clock. This time yesterday we were observing the position of the forest from Montmorency. If only we could see the position of Montmorency from the forest.
EMILE. But yesterday we could see the forest, and here we cannot see the town.
JEAN JACQUES. That is just it. If we could only find it without seeing it.
EMILE. Oh! my dear friend!
JEAN JACQUES. Did not we say the forest was…
EMILE. North of Montmorency.
JEAN JACQUES. Then Montmorency must lie…
EMILE. South of the forest.
JEAN JACQUES. We know how to find the north at midday.
EMILE. Yes, by the direction of the shadows.
JEAN JACQUES. But the south?
EMILE. What shall we do?
JEAN JACQUES. The south is opposite the north.
EMILE. That is true; we need only find the opposite of the shadows. That is the south! That is the south! Montmorency must be over there! Let us look for it there!
JEAN JACQUES. Perhaps you are right; let us follow this path through the wood.
EMILE. (Clapping his hands.) Oh, I can see Montmorency! there it is, quite plain, just in front of us! Come to luncheon, come to dinner, make haste! Astronomy is some use after all.
Be sure that he thinks this if he does not say it; no matter which, provided I do not say it myself. He will certainly never forget this day's lesson as long as he lives, while if I had only led him to think of all this at home, my lecture would have been forgotten the next day. Teach by doing whenever you can, and only fall back upon words when doing is out of the question.
The reader will not expect me to have such a poor opinion of him as to supply him with an example of every kind of study; but, whatever is taught, I cannot too strongly urge the tutor to adapt his instances to the capacity of his scholar; for once more I repeat the risk is not in what he does not know, but in what he thinks he knows.
I remember how I once tried to give a child a taste for chemistry. After showing him several metallic precipitates, I explained how ink was made. I told him how its blackness was merely the result of fine particles of iron separated from the vitriol and precipitated by an alkaline solution. In the midst of my learned explanation the little rascal pulled me up short with the question I myself had taught him. I was greatly puzzled. After a few moments' thought I decided what to do. I sent for some wine from the cellar of our landlord, and some very cheap wine from a wine-merchant. I took a small43 flask of an alkaline solution, and placing two glasses before me filled with the two sorts of wine, I said.
Food and drink are adulterated to make them seem better than they really are. These adulterations deceive both the eye and the palate, but they are unwholesome and make the adulterated article even worse than before in spite of its fine appearance.
All sorts of drinks are adulterated, and wine more than others; for the fraud is more difficult to detect, and more profitable to the fraudulent person.
Sour wine is adulterated with litharge; litharge is a preparation of lead. Lead in combination with acids forms a sweet salt which corrects the harsh taste of the sour wine, but it is poisonous. So before we drink wine of doubtful quality we should be able to tell if there is lead in it. This is how I should do it.
Wine contains not merely an inflammable spirit as you have seen from the brandy made from it; it also contains an acid as you know from the vinegar made from it.
This acid has an affinity for metals, it combines with them and forms salts, such as iron-rust, which is only iron dissolved by the acid in air or water, or such as verdegris, which is only copper dissolved in vinegar.
But this acid has a still greater affinity for alkalis than for metals, so that when we add alkalis to the above-mentioned salts, the acid sets free the metal with which it had combined, and combines with the alkali.
Then the metal, set free by the acid which held it in solution, is precipitated and the liquid becomes opaque.
If then there is litharge in either of these glasses of wine, the acid holds the litharge in solution. When I pour into it an alkaline solution, the acid will be forced to set the lead free in order to combine with the alkali. The lead, no longer held in solution, will reappear, the liquor will become thick, and after a time the lead will be deposited at the bottom of the glass.
If there is no lead44 nor other metal in the wine the alkali will slowly45 combine with the acid, all will remain clear and there will be no precipitate.
Then I poured my alkaline solution first into one glass and then into the other. The wine from our own house remained clear and unclouded, the other at once became turbid, and an hour later the lead might be plainly seen, precipitated at the bottom of the glass.
"This," said I, "is a pure natural wine and fit to drink; the other is adulterated and poisonous. You wanted to know the use of knowing how to make ink. If you can make ink you can find out what wines are adulterated."
I was very well pleased with my illustration, but I found it made little impression on my pupil. When I had time to think about it I saw I had been a fool, for not only was it impossible for a child of twelve to follow my explanations, but the usefulness of the experiment did not appeal to him; he had tasted both glasses of wine and found them both good, so he attached no meaning to the word "adulterated" which I thought I had explained so nicely. Indeed, the other words, "unwholesome" and "poison," had no meaning whatever for him; he was in the same condition as the boy who told the story of Philip and his doctor. It is the condition of all children.
The relation of causes and effects whose connection is unknown to us, good and ill of which we have no idea, the needs we have never felt, have no existence for us. It is impossible to interest ourselves in them sufficiently to make us do anything connected with them. At fifteen we become aware of the happiness of a good man, as at thirty we become aware of the glory of Paradise. If we had no clear idea of either we should make no effort for their attainment; and even if we had a clear idea of them, we should make little or no effort unless we desired them and unless we felt we were made for them. It is easy to convince a child that what you wish to teach him is useful, but it is useless to convince if you cannot also persuade. Pure reason may lead us to approve or censure, but it is feeling which leads to action, and how shall we care about that which does not concern us?
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