length of the horizontal rod. With 1. Loosen all the strings but the length given above-that is, one-preferably one of the middle where the vibrating rods are equal strings. Pluck or bow it first ex-it will be like that in Fig. 2. Unless the rods have been very exactly adjusted, the figure will change, becoming in turn each of those represented in the illustration. Other curves are shown in Figs. 3 and 4, and many others still will be obtained by sliding the rod Dones, called "overtones," beside in and out. VIOLIN, Experiments with a. These can be tried equally well on a banjo, or guitar, but a violin bow is necessary for some of them. actly in the middle and then close to one end, listening carefully. There is a difference in the sound, which has more "twang" when the string is plucked at the ends. This is because the note given by the string is composed of several faint the loud one which is most plainly heard, and more overtones are present when the string is plucked at the end. 2. Press the finger firmly down C Sonometer. paper and hang it over the string where the node ought to be. When the string is made to vibrate the paper will be agitated only a little, whereas if it be moved along a little way it will shake violently, or be thrown off the string. By touch skilled violin player can make it vibrate in four, five or more sections. Notes thus produced are called "harmonics." exactly on the middle of the string, | parts, bend a little narrow strip of and sound it again. The note heard will be an octave higher than the original note. Touch the finger lightly to the same spot, and sound the note as before. The result will be the same, but by looking closely it will be seen that both halves of the string are vibrating. By pressing different points of the string a ing the string at a third its length from the bottom and drawing a bow across the smaller part, the fifth above the note given by the whole string is obtained. By touching the same spot lightly and bowing as before, the whole string can be made to vibrate, the longer part vibrating in halves. The whole string thus vibrates in three parts. The points between the vibrating parts, which are almost still, are called "nodes." If it cannot be seen that the string is vibrating in This experiment will succeed better if a Sonometer is used, which is easily made as follows: Take a piece of violin string, or piano wire, a little longer than the table you wish to use. Tie it to a nail at one end of the table and pass it over a pulley screwed horizontally into the other end. To the end of the string tie a tin pail filled with sand, nails or scraps of iron. It may, instead, be fastened to a second nail, as in the diagram, but the other way is best, as the pull on the string can then be easily altered. The string should now be flat on the table, or nearly so. Cut wedge-shaped sticks of wood and place them under the string, as shown in the picture at A, B and D. By letting the wedges at the ends remain and moving the third, the same results will follow as if the string were touched with the finger. Two ways of vibrating are shown in the diagram, the nodes being at C. The weight of the pail can be varied by taking out or putting in nails or sand, thus stretching the string to the desired degree. 3. Sound a string and then touch it lightly in the middle. It will give the octave faintly. 4. Loosen all the strings of a violin but two, and tune those to the same note, pluck one, and then stop it; the other will continue to sound. Tune one slightly higher or lower than the other, and try the same experiment. The second string will still sound, but not as loud or as long as before. This is called "sympathetic vibration." The notes which are most sympathetic, or are set in motion most easily by a vibrating string, are the same note, its octave, the fifth above the octave, the second octave, and the third and fifth above that. This is shown best by experiments on the PIANO. 5. Tune the two lower strings as nearly as possible to the same note, and loosen the others. Place the ear behind the drum, if the instrument be a banjo, or close to the openings in the body, if it be a violin or guitar. Pluck the two strings together, and the resulting sound will be heard, first louder and then softer, in waves or pulsations. These are called beats. If they are not heard, raise or low er the pitch of one of the strings a little. The beats will be slower the nearer in tune the two strings are, and faster the farther they are apart; but if the notes are not very near, the beats will be so fast that they cannot be distinguished. | They can be heard still better with TUNING FORKS. VITESSE. A game played by two persons, each with a full pack of CARDS. Each player sits with his pack face downward before him, and at a signal both begin to turn over their cards one by one, face outward, and throw them on the table. They do not take turns, but each plays as fast as he can, repeating as he does so the names of the thirteen cards from Ace to King. over and over again, one for each card he turns. Whenever the card turned is the same as the one called out, he must lay it by itself, and begin again at the Ace in calling out. The player who first lays aside thirteen cards in this way wins. But if a card is once passed that should have been thrown out, the player must go on as if it had been any other card. The game of Vitesse thus requires quickness of hand and eye, and at the same time close attention, and a practised player will always win over a beginner, though it looks so simple. The word Vitesse is French, and means Quickness. VOLTAIC PILE. A kind of ELECTRIC BATTERY, named after its inventor, Alexander Volta. A simple one may be made as follows: Take a glass tube about an inch in diameter-an argand lamp chimney from which the lower part has been removed may be used. Paste two sheets of ordinary gold paper back to back and cut out disks just large enough to slip into the tube. The disks can be cut several at a time by first folding the paper. Cut an equal number of disks in like manner from silver paper, and then make a pile of them, gold alternating with silver. The tube must thus be filled with the disks pressed together as tightly as possible, and closed at each end with a cork, through which passes a wire touching the end disk. A LEYDEN JAR may be charged with such a pile by connecting one wire with the knob and the other with the outer coating. The electricity in the pile will last a long time, VOWELS, THE. A game played by any number of persons who sit in a row. Each, in turn, asks a question of his right-hand neighbor, at the same time requiring him to answer without using some one vowel. If the vowel is used in the answer, the offender pays a forfeit. W WALKING TRIPS. In making a | was devised by Russell A. Bigelow, walking trip as few things as possible should be carried, as every pound of weight adds to the fatigue. In this article only necessities are considered. Outfit. The shoes should fit the feet easily, and the soles should be neither so heavy that their weight is uncomfortable, nor so light that the feet feel through them the roughness of the ground. Low shoes should not be worn, as they admit dust and dirt. For climbing rocky hills or mountains heels filled with iron nails are best, as they hold to the rocks. Steel should not be used, as it is hard and slippery. The inside of the sole should be perfectly smooth. A roughness or lump which would not be noticed in an ordinary walk may become painful after a tramp of twenty or thirty miles. The best plan is to wear movable leather in-soles. As soon as the least lump is perceived the shoe should be taken off, the sole removed, and part of its under surface pared off with a sharp knife, just under the uncomfortable spot. If this is done faithfully, the soies will be perfectly fitted to the feet at the end of a day's walk, and the trouble of doing it will be amply repaid by the increased comfort. This simple method of adapting the sole to the foot a New York lawyer. Some people put sweet oil or salve on the feet when they begin to chafe, and they should be washed frequently. The other articles of dress may be according to the fancy of the wearer, so long as they are easyfitting and comfortable. For warm weather, gauze underclothing and a loose flannel shirt are best, with a light jacket to wear when not walking. For colder weather the shirt may be tighter at the wrists and neck and the underclothing thicker. In all seasons knee-breeches and a soft hat are best. One can buy a knapsack, which may be strapped on the back, or, if his bundle is small, it may be carried in the hand. It is generally better to carry a small weight in the hand than in a knapsack. Other articles that may be carried are slippers, to rest the feet at night (some think that these should be taken, even if nothing else is); a change of underclothing; needle and thread; buttons; adhesive plaster; fish-line and hooks; extra handkerchiefs; pen, ink and paper; a ball of twine and matches. If the trip is to last more than a few days, so that a change of underclothing is positively necessary, it may be packed in a valise and sent by express to some town on the road. One valise can usually be made to answer for a party of four or five. day at a rate of three miles an hour is quite enough. In a long trip, lasting many weeks, the muscles become hardened, and much more than this can be done - thirty-five miles a day, or perhaps even forty; but this is an extreme. For most boys under eighteen years, twenty miles will be found quite enough; and this distance must be lessened, if weight is to be carried. The best time to walk is in the morning and late in the afternoon, taking a long rest at noon, before and after the mid-day meal. It is best both to retire and to rise early. If the legs and feet feel hot and full of blood while walking, it is a great relief to lie on the back and hold them up as straight as possible against a tree or wall for a few minutes. If the whole body is tired, one of the best resting postures is to lie flat on the face on the ground. This is said to be a favorite position with the Indians when tired. But there is no reason why more than a pleasant degree of fatigue should ever be felt, if the walker does not overdo. A cane or staff is a great aid in climbing, or in the latter part of the day, when the walker is tired; but as it is often in the way, it is best to cut a fresh one when it is wanted. Shelter and Food. In some parts of the country it is possible so to arrange the trip that every night shall be spent at a hotel. Otherwise it is necessary to ask for shelter at farmhouses, or in a very wild country to CAMP OUT; but this requires extra luggage. In some parts of the United States it is very easy to get shelter for the night at a farmhouse; elsewhere it is often impossible. If the walking party wish to stay at farm-houses, they should inquire beforehand of some one who knows the country whether they can do so without trouble. The midday meal should be light, unless a rest of several hours is taken after it. No food should be taken when tired, and it is best to rest at least half an hour before eating. The pedestrian is apt to be very thirsty, especially on a warm day. Many authorities say that no water at all should be taken while walking, and that the blood should be cooled by simply bathing the wrists and temples freely at intervals, or plunging the arms into water up to the el-ing. The change of life and exbows. Others drink freely of spring water. Perhaps it is best for each to decide for himself which way is best. Distance and Hours. Unless the walker has been used to walking eight or ten miles a day, he should go not more than fifteen miles on the first day, and increase this distance by two or three miles a day till he feels he has reached the limit of comfort, say twenty-five or thirty miles. The tendency of beginners is to walk as far as they can the first day, with the result that they are too lame on the next day to go more than five or six miles without pain. Ten hours a The walker generally suffers from sunburn during the first two or three days, but it usually ceases after a time. The second day of the march is generally most fatigu citement often keep him from sleeping soundly through his first night, and he often feels tired when he wakes. The fresh air makes him very thirsty, and his stomach often becomes disordered. These symptoms, however, will soon pass away. No medicines nor alcohol should be taken, though laxative food, such as fruits, is good. Routes. The general road to be followed should be studied on the map before starting, leaving the exact route to be decided on from day to day. For parts of the country that are the resorts of tourists there are guide-books, giving the best routes, the names of hotels on the Kings 13. This is repeated till the pack is out, when there will be four cards in each pile, except where a card has been put aside. The top card of those laid aside is now taken and slipped under the pile having the corresponding number. The top card of that pile is slipped under its proper pile, and so on till one is reached that is in its proper place. Then the next card of those laid aside is taken, and so on till all have been used. The player has won if the pack is arranged at the end of the game in 13 piles each of which contains four cards of the same value. road, and much other information. If part of the route lies over a country where there is no road, the direction of the nearest town must be found out from a map or otherwise. A pathless walk of more than an hour requires a compass. While walking in a forest it is necessary to get the right direction only at first; it can be kept by "lining' trees. This is done by selecting three trees on a line with the eye in the proper direction; after the nearest is passed another is taken, beyond the last, so that three are always kept in view. It is never safe to trust to instinct to keep in a straight line in the woods, for most Clock, The. A variation of the people naturally walk in a circle, preceding game. Cards are placed owing to the fact that one leg is in twelve piles of four each, face slightly stronger than the other. downward in a circle, and numPersons lost in the woods have oft-bered to correspond with the figen travelled thus in a circle, some-ures on a clock dial. The thirtimes for days. Party. A large party is more enjoyable in some respects, but it has the disadvantage that some will always want to walk farther than others,and that it is difficult to agree on the route, the hours, and the resting places. The best plan is either to choose a leader with power to decide these things, or for all to agree to follow the wishes of a majority. When one person walks alone, he can do exactly as he pleases, but such a trip is apt to be lonely, and it is also dangerous, for in case of accident there is no one to give or obtain aid. teenth pile is placed in the centre. The top card of the middle pile is now turned and placed face upward under its proper pile, and so on, as in the game just described. WATCH, Experiments with a. 1. Close the ears tightly, and hold the watch firmly between the teeth. The ticking will be heard distinctly, because the sound is conducted through the teeth and the bones of the head to the inside of the ear. 2. Let one person hold the watch against the end of a long pole, and let another press the other end of the pole against his ear, or hold it between his teeth. He will hear the watch tick distinctly, the sound being conducted along the pole. WANDERING CARD. A SOLITAIRE game of CARDS, played with one full pack. The first 13 cards 3. Let one person hold the watch that are taken from the pack are and another walk slowly away till laid in a row, as they come, face he just ceases to hear the ticking. upward. The next 13 are laid on Let the first person now hold the these in the same order. As each watch in front of a concave mirror, of the second 13 is played, the such as is used for lamp reflectors. number of the pile on which it is The second person will find that he placed is spoken, and if the num- can hear the watch tick if his ear is ber of pips on the card is the same, directly in front of the mirror, but the card is laid aside, and the that the sound ceases if he moves next card is laid on the next pile. to one side or the other. (See REKnaves count as 11, Queens 12, and | FLECTION of Sound.) |