apart. They may be bought at a music store. A tuning fork may be sounded by rapping it on the edge of a table, by pressing the prongs together with the teeth and then suddenly releasing them, or by striking it with a stick. EXPERIMENTS. Sound a tuning fork, and while it is vibrating touch the end to a bare table. This sound will be greatly increased. This is because the table vibrates in sympathy with the fork, so that there is a larger sounding surface. 2. Sound the fork and hold it in succession close to the mouths of bottles and jars of various sizes, pouring in water while the fork is vibrating. When the volume of air in the jar is just large enough, it will vibrate in sympathy with the fork, giving out a loud sound. ried about in the hand. Sound a fork, touch it to a resonance box, and walk slowly toward the wall with the fork. The note given wili be now louder, now fainter. This is caused by the interference of the sound reflected from the wall with that proceeding directly from the fork. 5. Hold two forks tuned to the same note on resonance boxes several feet apart. They can be tuned together by sticking bits of wax on the prongs of the one which gives the highest note. The wax will load the prong, making it move more slowly and give a lower note. Sound one of the forks, and after a few seconds stop it. The other one will be found vibrating slightly. Its note can often be heard by placing the ear to the opening in the resonance box. If this does not succeed, the vibration can be detected by holding against one of the prongs a bit of glass as large as a pea, fastened to a thread by means of sealing-wax. This is a case of "sympathetic vibration," other examples of which are given under VIOLIN. The experiment will not succeed unless the forks 3. Turn the fork around slowly while it is over the jar. The sound will rise and fall in loudness, being almost nothing when the corners of the prongs are toward the jar. Hold the fork up to the ear, turning it in like manner, and the same result will follow. This is because in this position the sound-waves be tuned to the same note. from the inside of the prongs 6. Load one of the forks with interfere with those from the out-wax so that it is almost, but not side. 4. Make a cardboard or paper roll, just large enough to go over one prong of the fork, and while it is in the position where it makes least noise, either in front of the ear or over the jar, slip the roll over one prong. The sound will at once increase, owing to the fact that the waves from one prong are cut off and cannot interfere with those from the other. 4. Make a wooden box about six inches long, four inches wide, and two inches thick, open at the ends. This is called a resonance box, and makes the fork sound louder, just as a table does; but it is more convenient, because it can be car quite, in tune with the other. Sound them both at once, and "beats will be heard, just as in Experiment 5, under VIOLIN. 7. Sound a fork and dip the prongs into a basin of still water. The vibration will cause curious ripples. 8. Gum a piece of tin-foil or a bristle to one prong of a fork; set the fork vibrating, and then draw it over a piece of smoked glass. The vibration of the fork will make the bristle draw a wavy line on the glass. 9. Touch one end of a long rod or pole to a resonance box, and touch a vibrating tuning fork to the other end. The rod will con of a glass tumbler, seeing that it touches the rim all around. Slide the glass slowly to one side, holding a vibrating tuning fork to the opening. When it reaches the right size, the air in the tumbler will give out a loud sound, in answer to the fork. (See A, in Fig. 1.) 13. Take a piece of thin paper, and, having wet it, paste it over the mouth of the tumbler. When it is dry, cut away part at one end so as to make a hole bounded by the edge of the tumbler and a straight line. Make this hole small at first, but cut away more and more of the paper till the air within answers the tuning fork as before. Sprinkle a little sand on the paper and sing the note given by the fork. The sand will dance up and down. (See B, in Fig. 1.) 14. Tilt the tumbler by placing a book under one side (see B, in illustration), so that the sand almost runs down the paper by its own weight. If the proper note be now sung in any part of the room the sand will begin to move down the paper, but it will not move for any other note. If the gamut be sung, for instance, the sand will keep still till its own note is reached, when it will move at once. 15. Dip the mouth of a tumbier, five or six inches deep, into a soap solution (see SOAP BUBBLES), and then slide the glass plate through the soap water under the mouth. Take tumbler and glass out of the water and stand them on the table. Slide off the glass while sounding the fork as in Experiment 12. There will be a soap film over the opening thus made, which, as soon as the air in the tumbler responds to the fork, will be covered with curious wrinkles. To see these to advantage, the light of the sky must be reflected from the film. 16. Tune two wide mouthed bottles or glasses of equal size, by slipping pieces of glass over their Fig. 2. mouths, as in Experiment 12, so that each will strengthen the vibration of the tuning fork. Stand one upright and lay the other on its side on a pile of books so that the mouths of the bottles just touch. The bottle on the books is kept from rolling off by bits of wax, and the glass over its mouth is held in place in the same way. Vibrate the fork and hold it horizontally between the mouths of the bottles. A position will be found where almost no sound at all is heard. This is because the sound from one bottle interferes with that from the other. If a piece of paper be slipped between the fork and the mouth of either bottle the sound will at once be heard again (Fig. 2). 17. Suspend a light piece of cardboard by a string near a vibrating tuning fork; it will be attracted. Hold a candle flame near the fork: it will be repelled. This is because the sound-waves in air attract bodies heavier than air, and repel those which are lighter. 18. Tie a silk thread six inches long to one prong of a tuning fork, and to the other end of the thread fasten a button or other object of slight weight. Vibrate the fork, holding it horizontally, and the thread will also vibrate, dividing up into segments, between which are points of no motion, or "nodes." (See VIOLIN, Experiment 2.) The number of segments seen when the fork is held with prongs side by side is double that when one prong is over the other. The number of segments is also greater when the weight on the thread is less. TURKS AND RUSSIANS. A game played by two persons with slate and pencil. About a quarter of the slate is marked off by a line at each end, and in each of the compartments so marked off are made a number of dots about the size of a pin-head, those at one end representing Turks and the others Russians. The number of Turks and Russians may be large or small, as agreed on, but must be equal. At one end of each compartment is a small square which serves as a battery. Each player, in turn, places the point of his pencil in his own battery, and then draws a line quickly in the direction of his enemy's men. The line must have no angles in it, but may be straight or curved. Those dots through which the line passes are considered dead men, and he who first kills all of the enemy's men is the winner. Sometimes the players are required to shut their eyes or turn away their heads, when drawing their lines. TWELFTH DAY. The sixth day of January; so called because it is the twelfth day after CHRISTMAS. It is also the feast of the Epiphany, on which is celebrated the visit of the three Magi, or Wise Men, to the infant Christ. In ancient times Twelfth Night was celebrated with great merriment and many games, and Twelfth Night parties are occasionally given now. As the wise men who visited Christ are said by tradition to have been three kings, one of the chief amusements of Twelfth Night is the choosing of a King and Queen by means of colored beans baked in cakes, whence it is sometimes called the "Bean King festival." One cake is cut into pieces and given to the boys and the other to the girls, and the boy and girl who find the beans in their pieces become King and Queen. Cards having written on them various titles, such as Prime Minister, First Lady in Waiting, etc., are now placed in two bags, the boys' titles in one bag and the girls' titles in the other. Enough blank cards are mixed with them to make the whole number equal that of the guests. Each guest now draws a card and assumes the title, if any, written on it. The hostess may provide appropriate costumes for the King, Queen, and Courtiers. The evening is usually spent in playing games. Among the amusements of Twelfth Night in ancient England were the blowing up or burning of pasteboard castles. A pastry stag, out of which flowed blood made of claret, was sometimes served on the table, and the guests pelted each other with eggshells filled with rose-water. Shakespeare's play of this name was so called because written for a Twelfth Night party. TWENTY QUESTIONS. A game played by any number of persons, divided into two opposing parties, one of which tries to find out, by twenty questions and one or more guesses, a subject chosen by the other. Captains. In order to avoid confusion, questions are asked and answered only by the captains or leaders of the two parties; but before each question there is a consultation of all the players on the side that is to ask it, and the best answer is decided on by the other side in the same way. Umpire. An umpire is generally chosen beforehand, to decide disputed points, and to avoid dispute he may take down in writing each question and answer as it is spoken. Time Limit. In order to avoid taking too much time, it is usual to require a question or answer to be given within a certain time after the preceding answer or question. This time limit (usually three or four minutes) is agreed upon at the beginning of the game. Guessing. When the questioning side have asked their twenty questions, or as many as they wish, they proceed, through their captain, to guess the subject. Sometimes only one guess is allowed, sometimes two or three, as agreed on before the game. If more than one is permitted, all but the last may be asked during the questioning. Thus, if there are to be three guesses, the questioners may ask ten questions, then make a guess; then six more, then make another guess, and so on. But if the last guess is wrong, wherever it may be made, the guessers lose the game. The subject must be guessed exactly as it is chosen. For instance, if it is " Mr. B.'s left eye," and the guess be “One of Mr. B.'s eyes," the answer must be "No." But if the question be asked, "Is it one of Mr. B.'s eyes?" the answer is "Yes." Then, if more than one guess is allowed, the right and left eyes can be guessed in succession. If not, "Is it his story of the New York City Hall. | sessed by subjects which are either Here, after finding out that the far away or immaterial, like the subject is "A pane of glass," at "Garden of Eden," or "Courage.” least seven more questions are re- A beginner might be quite unable quired to locate it, since questions to guess either of these, but each like "In what part of the City Hall consists of but one thing, and eithis it?" are barred out, the answer er may be guessed in a comparativebeing a part of the subject. By ly few questions. The best subjects making the subject complex are those that combine these two enough, it can thus be made im- kinds of difficulty, as " The petal of possible to guess it even in twenty a rose on the east side of the Garden questions; but subjects of this kind of Eden," or "The Courage of Israel do not add to the interest of the Putnam in entering the wolf's den." game, and they should be restricted Subjects may also be adapted to by rule. the questioners. If they are not well acquainted with history, an Another kind of difficulty is pos |