exclusion of everything else! At last we discover that this property is communicated to the iron itself, which is, so to speak, endowed with life. We go to the fair one day42 and a conjuror has a wax duck floating in a basin of water, and he makes it follow a bit of bread. We are greatly surprised, but we do not call him a wizard, never having heard of such persons. As we are continually observing effects whose causes are unknown to us, we are in no hurry to make up our minds, and we remain in ignorance till we find an opportunity of learning.
When we get home we discuss the duck till we try to imitate it. We take a needle thoroughly magnetised, we imbed it in white wax, shaped as far as possible like a duck, with the needle running through the body, so that its eye forms the beak. We put the duck in water and put the end of a key near its beak, and you will readily understand our delight when we find that our duck follows the key just as the duck at the fair followed the bit of bread. Another time we may note the direction assumed by the duck when left in the basin; for the present we are wholly occupied with our work and we want nothing more.
The same evening we return to the fair with some bread specially prepared in our pockets, and as soon as the conjuror has performed his trick, my little doctor, who can scarcely sit still, exclaims, "The trick is quite easy; I can do it myself." "Do it then." He at once takes the bread with a bit of iron hidden in it from his pocket; his heart throbs as he approaches the table and holds out the bread, his hand trembles with excitement. The duck approaches and follows his hand. The child cries out and jumps for joy. The applause, the shouts of the crowd, are too much for him, he is beside himself. The conjuror, though disappointed, embraces him, congratulates him, begs the honour of his company on the following day, and promises to collect a still greater crowd to applaud his skill. My young scientist is very proud of himself and is beginning to chatter, but I check him at once and take him home overwhelmed with praise.
The child counts the minutes till to-morrow with absurd anxiety. He invites every one he meets, he wants all mankind to behold his glory; he can scarcely wait till the appointed hour. He hurries to the place; the hall is full already; as he enters his young heart swells with pride. Other tricks are to come first. The conjuror surpasses himself and does the most surprising things. The child sees none of these; he wriggles, perspires, and hardly breathes; the time is spent in fingering with a trembling hand the bit of bread in his pocket. His turn comes at last; the master announces it to the audience with all ceremony; he goes up looking somewhat shamefaced and takes out his bit of bread. Oh fleeting joys of human life! the duck, so tame yesterday, is quite wild to-day; instead of offering its beak it turns tail and swims away; it avoids the bread and the hand that holds it as carefully as it followed them yesterday. After many vain attempts accompanied by derisive shouts from the audience the child complains that he is being cheated, that is not the same duck, and he defies the conjuror to attract it.
The conjuror, without further words, takes a bit of bread and offers it to the duck, which at once follows it and comes to the hand which holds it. The child takes the same bit of bread with no better success; the duck mocks his efforts and swims round the basin. Overwhelmed with confusion he abandons the attempt, ashamed to face the crowd any longer. Then the conjuror takes the bit of bread the child brought with him and uses it as successfully as his own. He takes out the bit of iron before the audience—another laugh at our expense—then with this same bread he attracts the duck as before. He repeats the experiment with a piece of bread cut by a third person in full view of the audience. He does it with his glove, with his finger-tip. Finally he goes into the middle of the room and in the emphatic tones used by such persons he declares that his duck will obey his voice as readily as his hand; he speaks and the duck obeys; he bids him go to the right and he goes, to come back again and he comes. The movement is as ready as the command. The growing applause completes our discomfiture. We slip away unnoticed and shut ourselves up in our room, without relating our successes to everybody as we had expected.
Next day there is a knock at the door. When I open it there is the conjuror, who makes a modest complaint with regard to our conduct. What had he done that we should try to discredit his tricks and deprive him of his livelihood? What is there so wonderful in attracting a duck that we should purchase this honour at the price of an honest man's living? "My word, gentlemen! had I any other trade by which I could earn a living I would not pride myself on this. You may well believe that a man who has spent his life at this miserable trade knows more about it than you who only give your spare time to it. If I did not show you my best tricks at first, it was because one must not be so foolish as to display all one knows at once. I always take care to keep my best tricks for emergencies; and I have plenty more to prevent young folks from meddling. However, I have come, gentlemen, in all kindness, to show you the trick that gave you so much trouble; I only beg you not to use it to my hurt, and to be more discreet in future." He then shows us his apparatus, and to our great surprise we find it is merely a strong magnet in the hand of a boy concealed under the table. The man puts up his things, and after we have offered our thanks and apologies, we try to give him something. He refuses it. "No, gentlemen," says he, "I owe you no gratitude and I will not accept your gift. I leave you in my debt in spite of all, and that is my only revenge. Generosity may be found among all sorts of people, and I earn my pay by doing my tricks not by teaching them."
As he is going he blames me out-right. "I can make excuses for the child," he says, "he sinned in ignorance. But you, sir, should know better. Why did you let him do it? As you are living together and you are older than he, you should look after him and give him good advice. Your experience should be his guide. When he is grown up he will reproach, not only himself, but you, for the faults of his youth."
When he is gone we are greatly downcast. I blame myself for my easy-going ways. I promise the child that another time I will put his interests first and warn him against faults before he falls into them, for the time is coming when our relations will be changed, when the severity of the master must give way to the friendliness of the comrade; this change must come gradually, you must look ahead, and very far ahead.
We go to the fair again the next day to see the trick whose secret we know. We approach our Socrates, the conjuror, with profound respect, we scarcely dare to look him in the face. He overwhelms us with politeness, gives us the best places, and heaps coals of fire on our heads. He goes through his performance as usual, but he lingers affectionately over the duck, and often glances proudly in our direction. We are in the secret, but we do not tell. If my pupil did but open his mouth he would be worthy of death.
There is more meaning than you suspect in this detailed illustration. How many lessons in one! How mortifying are the results of a first impulse towards vanity! Young tutor, watch this first impulse carefully. If you can use it to bring about shame and disgrace, you may be sure it will not recur for many a day. What a fuss you will say. Just so; and all to provide a compass which will enable us to dispense with a meridian!
Having learnt that a magnet acts through other bodies, our next business is to construct a bit of apparatus similar to that shown us. A bare table, a shallow bowl placed on it and filled with water, a duck rather better finished than the first, and so on. We often watch the thing and at last we notice that the duck, when at rest, always turns the same way. We follow up this observation; we examine the direction, we find that it is from south to north. Enough! we have found our compass or its equivalent; the study of physics is begun.
There are various regions of the earth, and these regions differ in temperature. The variation is more evident as we approach the poles; all bodies expand with heat and contract with cold; this is best measured in liquids and best of all in spirits; hence the thermometer. The wind strikes the face, then the air is a body, a fluid; we feel it though we cannot see it. I invert a glass in water; the water will not fill it unless you leave a passage for the escape of the air; so air is capable of resistance. Plunge the glass further in the water; the water will encroach on the air-space without filling it entirely; so air yields somewhat to pressure. A ball filled with compressed air bounces better than one filled with anything else; so air is elastic. Raise your arm horizontally from the water when
