CALL-BALL, CALLIE BALL, or BALLIE CALLIE, a game of ball played by any number of persons, with a hard rubber ball. The ball is thrown against a wall by one of the players, who at the same time calls out the name of one of the others. The player named must strike the ball as it bounds back, calling another name as he does so. If he miss it he must pick it up, and call "Stand!" whereupon the other players, who have begun to run as soon as he makes the miss, stand still. He throws the ball at one, and if he strikes him that one must throw the ball at the wall, as before. If he miss the player at whom he throws, he must place himself against the wall while the others throw the ball at his back in turn, as in ROLY POLY. This game was common in New England many years ago, and is still played in Austria. The English poet Herrick alludes to a similar game in his lines: "I call, I call; who doe ye call? The maids to catch this Cowslip ball. In the Middle Ages boys and girls played a kind of call-ball where he who obtained possession of it threw it to the one he loved best. CAMERA LUCIDA, an arrangement to aid in drawing the outline of small objects. There are several kinds, but the simplest is made as follows: Fig. 1. Sit at a table in front of the object, which should be supported on a book (Fig. 1). Lay a sheet of white paper on the table between yourself and the object, and on the farther edge of the paper rest the edge of a pane of glass. Incline the glass toward you, and presently you will see in it the reflection of the object to be drawn. At the same time you will see the paper through the glass. The glass may now be rested against a book to keep it in position. Hold your pencil on the paper under the glass and see whether you can see the reflection and the pencil point plainly at the same time. If either of them looks double while you are fixing your eyes on the other, it shows that the object is either too far away or too near. Move the book on which it rests backward and forward until you can see both the reflection and the pencil point plainly. Keeping the eye perfectly still, the outline of the reflection can now be followed on the paper with the pencil, and thus a very exact picture can be drawn. The picture will be of the same size as the object, hence only small objects, like flowers, insects, coins, or small wood-cuts, can be used. To draw large objects or landscapes by tracing in the same way, a CAMERA OBSCURA may be used, as in PHOTOGRAPHY, but a large Camera Lucida is sometimes arranged as in Fig. 2. The words CAMERA LUCIDA are Latin for Light Chamber. CAMERA OBSCURA. To make a rough camera, take a little paste ily distinguished. The picture will grow clearer as the eye becomes accustomed to the light. By moving the box so that the pinhole turns in a different direction, the picture will change. The smaller the pinhole is, the less blurred the picture will be, but it will be also less bright. With a hole about of an inch in diameter the picture will be quite bright, but so blurred that it is hard to tell different objects from each other. The box should not be more than an inch deep, as the farther the back is from the pinhole, the less distinct the picture will be. In the evening, such a camera will give an excellent picture of a lamp or candle, and even of a person's face held very near a bright light. The way the picture is made may be understood by looking at Fig. 2, where the lines rep resent rays of light from different parts of an object passing through the pinhole and striking the back of the box. When the cover is taken from the box, rays from all parts of the object strike every part of the box at once and are mixed together, hence there is no picture, but only a white blur. A camera which will make the picture bright without blurring it may be made by using a glass lens (See LENSES, EXPERIMENTS WITH). These experiments show how a lens will throw a picture, and the picture can be seen to better advantage if the lens be fixed in a hole in the side of a box. The observer may work at the picture through a hole in the top of the box, or the back of the box may be made of thin white paper, so that the picture will show on the other side. There is a certain distance from the lens for every object, where its image will be plainest, so it is a good plan to make the back of the box so that it can be slid in and out. Find the distance at which the lens makes the plainest picture of near objects before choosing the box, and then select one of the right depth. Remove the back, and saw off the edges so that it can be made to slip in as far as desired. Nail a stick to it to serve as a handle by which it may be pulled in and out. Hat Camera. A camera can be made also from a stiff felt or silk hat, if it have a ventilating hole in the top of the crown. If there are more than one of these holes, all but the central one may be stopped with paper. A piece of thin paper is then pinned over the bottom of the hat, which is held with the top toward the part of the landscape to be observed. A black shawl is thrown over the hat and the observer's head, but care must be taken that it does not hang over the ventilating hole. CAMPHOR. Experiments with. 1. Place a piece of gum camphor on water. After a time it will begin to move about on the surface, and will continue its motion till it is dissolved. The reason is that it dissolves more rapidly at some places than at others, so that the surface of the water pulls in a tightly stoppered bottle, and let more strongly on it in one direction than in another. The bit of camphor may be set on fire, and will then burn as it moves about. rod of gum camphor one-quarter inch square, following the grain of the gum, which can be seen on holding it up to the light. Touch the bottom of the vessel with this stick, and the water around it will be thrown into waves or ripples, which will continue till the end of the stick is dissolved away. The reason is that the water is first drawn up toward the stick as it would be toward the finger or a glass rod. But, a film of camphor forming on its surface, this is altered so as to act toward the stick as mercury would toward glass, that is, the water is depressed. It recovers itself, and the action goes on very rapidly. 2. Dust lycopodium powder over the surface of a dish of water by shaking it in a muslin bag. The water should be covered with a very faint layer of the powder. Dip into the water the end of a rod or stick of gum camphor. The lycopodium at once moves back from the camphor, and begins to revolve in several wheel-shaped figures. In order that this experiment may succeed the vessel and water must be quite clean, and the day should be dry and fine, so that the camphor film will evaporate soon after it forms. 3. Dissolve a bit of camphor the size of a pea in a drachm of benzine. Keep the solution in a phial in whose cork a pin is stuck, head downward, so that it protrudes into the liquid. Fill a concave microscope slide with clear water, and touch the surface with a little of the benzine-camphor liquid on the head of the pin. The drop, viewed through the microscope, behaves very curiously, little drops detaching themselves from its sides and moving about in all directions. 4. Pour a thin layer of water into a flat-bottomed shallow dish. Cut a 5. Place a piece of gum camphor it stand awhile in a warm room. Then set it close to a window and the side next the window will become covered with minute camphor crystals. This is because the camphor evaporates, and the coolness caused by the window condenses the vapor again. It was once thought that the light influenced the crystallization, but it will take place at night in the same way. Marks on the glass, invisible before, will often be shown by the arrangement of the camphor crystals, just as those on window panes often are by frost crystals. Thus, if the interior of the bottle be wiped out roughly with a moist cloth, and then allowed to dry, the crystals are apt to form along the lines made in wiping. (See also BREATH FIGURES.) CAMPING OUT. One kind of camping may be in connection with a WALKING TRIP, the campers spending their nights in a tent instead of at a hotel or farm-house, and preparing their own meals. Each person may carry about twenty pounds of luggage in a knapsack or haversack, or in a roll, whose ends are joined to make a ring which is thrown over the shoulder, as shown in the illustration. Each should take a rubber blanket, a woolen blanket, a change of clothing, towel, soap, comb, and toothbrush, besides including himself, once went on a his share of the general luggage, twelve days' camping trip and spent which includes the tent, cooking but one dollar apiece during that utensils, hatchet, and food. An time. They "carried coffee, sugar, easier but more expensive way is to pork, and beef from home, and ate have all the luggage carried in a potatoes three times a day." Frank wagon, leaving the walkers free. A E. Clark, in an account of three larger tent and more implements can weeks' camping on the seashore, thus be carried, and the expense is gives the following list of expenses usually not great if divided among for six persons: several. It is often a good plan to Tent for three weeks buy a horse and cart for such an Provisions taken with us expedition, selling both at the end of Stove and cooking utensils . the journey. If the camp is not to be Fresh provisions bought at the moved, the tent may be still larger, beach and many useful fixtures, such as Incidentals Fig. 1.-The Camper-Loaded. tables, a stove, an oven, bedsteads, etc., can be set up by any one of ingenuity. Total. 9.00 22.00 15.00 15.00 20.00 $81.00 or $4.50 per week for each camper. In general, the expense depends almost entirely on the way in which the campers are willing to live. GIRLS' CAMPS. What has been said above applies also to campers of the other sex, or of both sexes, except that ladies must not be expected to bear any hardships. A party of girls, in charge of an older woman may camp together very pleasantly in not too wild a country, hiring a man to do the hard work, such as pitching the tent. When the campers are of both sexes, the ladies will naturally be allotted the cooking and other housework, while the men do the rougher work. Insects. Campers are often annoyed by mosquitos and black flies, especially in the woods, and, where these pests exist, mosquito netting must be taken for protection at night. Many preparations for keeping inLocation. A camp should be on sects away by applications to the dry ground, sloping so as to give face and hands are to be bought, but drainage, and near good drinking most old campers prefer to drive water. Favorite sites are on moun- them away by making what is tains, at the edge of woods, on the called a "smudge." A fire is built bank of a lake, or on the seashore. to windward of the camp and smothExpenses. These vary at the pleas-ered with wet wood and damp leaves, ure of the camper, and according to so as to make a dense smoke. the number in the party. Mr. John The "smudge" is disagreeable, but M. Gould, in his book on "How to is a welcome relief after insects. Camp Out," relates that three boys, Rainy Days. If the rain is a cold. one, it is often necessary to build a fire just outside the tent, but it is difficult to keep one alive in a hard storm. If there is a stove in the camp, it may be brought inside the tent, the pipe projecting through the door, but unless this is on the leeward side the smoke will be blown back into the tent. Another way is to build a fire in a hole just outside the tent and conduct the smoke through a trench under the tent, covered with flat stones, the crevices being cemented with clay. It is difficult to make this smoketight, but when it is so, it warms the tent well. Each one of the campers should have his special duties assigned him. This may be done on trial at first, till it is seen for what work each is best fitted. Thus, in a camp of three, one may do the cooking, and another the dishwashing, while the third has general charge of the tent and its surroundings. Tents. The material is usually heavy drilling or duck for large tents. The simplest kind is a Shelter-tent, which consists merely of pieces of cloth with buttons and buttonholes at the edges, by which several can be fastened together. The buttonholes are near the edge, and the buttons several inches nearer the center. The pieces carried by the soldiers of the United States army in the Civil War were about five feet square. They can be fastened to Fig. 2.-Shelter Tent. gether, and put up in various ways; for instance, by throwing two over a ridge pole supported on two forked uprights, and fastening them at the bottom, by driving pegs through the buttonholes, or through loops of rope sewed there for the purpose. If two more pieces be buttoned across the ends, the tent is entirely inclosed. The tent poles and pegs are not carried, but cut at the spot where the tent is pitched. A shelter-tent (Fig. 2) is the best to use where the campers walk from place to place and carry all their own baggage. An end piece may be made to fit the end exactly, and sewed to one of the side pieces instead of buttoning it, if desired. The tent should usually be pitched with a right angle at the roof, but the angle must be sharper in rainy weather. Shelter-tents may be made also of rubber, which are perfectly waterproof, but heavy to carry. An A tent, or Wedge-tent (Fig. 4) is pitched over a ridge pole like a sheltertent, but is made all in one piece. A common size is about seven feet high, seven feet long, and eight feet wide. One end is usually closed, while the other has an opening in the middle, closed by a flap hanging on the inside. Around the bottom of the tent is sometimes hung a strip of cloth called a sod-cloth, to keep out draughts and prevent the edge of the tent from touching the ground and rotting. Fig. 3. Around the edge are also Tent Pin. sewed loops of rope called "beckets," through which wooden pins (Fig. 3) are driven into the ground, when the tent is pitched. The best tent for a permanent camp, or one where the heavy luggage is carried from place to place on a wagon, is the Wall-tent (Fig. 5). This is shaped like a house, with side walls about four feet high, and ridge pole about nine feet from the ground. At the corners of the eaves and at every seam along their sides loops of rope are fastened, and |