The exact origin of yogurt is not known. But we do know that this important dairy product dates back to biblical times and beyond. Yogurt was probably first eaten in the Middle East. In that region’s hot climate, milk spoils rapidly. For this reason yogurt, which does not spoil easily, was a welcome discovery. Yogurt no doubt developed some time in the distant past when certain bacteria accidentally got into some stored milk.

That is what yogurt is today milk in which two friendly strains of bacteria are grown. The names of these micro organisms are Lactobacillus bulgaricus and Streptococus thermophilus

How is yogurt made? In its most common form, yogurt is made from cow’s milk. Much of the fat is often removed and nonfat milk solids with extra protein are added. The milk is homogenized, pasteurized, and then injected with the bacteria. Sometimes fruit preserves and other ingredients are added. But in natural yogurt, no artificial flavor, color, or preservatives should be used.

The milk, now containing the bacteria, is piped into machines that fill the yogurt cups you see in the stores. These cups are then stored in incubators until the product reaches the custard like thickness typical of yogurt. Throughout this process, temperatures must be carefully controlled for the yogurt to develop properly.

Yogurt is a food with many uses. It is a good source of protein calcium, certain B vitamins, and minerals. Because of its nutrional value, many people eat yogurt as a supplement to their reguler diet or as a snack between meals. It can be enjoyed by itself or combined with other foods, such as apple sauce, peanut butter, or dry cereal. Many cooks use yogurt in recipes for salad dressings, desserts, and main dishes.

Yogurt is a popular food in many parts of the world. In Finland it is glumes, in Norway kyael meelk, and in Russia prostokvasha. In India, the Balkans, and the Middle East, yogurt is used as an ingredient in many dishes.

Food markets in the United States offer different types of yogurt. There is the sundaestyle yogurt, with fruit on the bottom; Swissstyle, with fruit throughout; and westernstyle, with fruit on the bottom and fruit coloring and sweetening on top. Two of the most popular types of yogurt are frozen yogurt on a stick and soft frozen yogurt served from machines.

Some people make yogurt at home with their own yogurt machine. The instructions, which come with the machine, must be followed carefully. For example, unless the milk is kept at the right temperature, the bacteria cannot live. The result would then be sour milk, not yogurt.

“The circus is coming to town!” this news long has heralded one of the most exciting events of childhood. Each year the people of almost every citi and large town could look forward to at least one big top show. Many circuses traveled te length and breadth of the land during the months of warm weather. Some were small one ring shows. Today large shows, such as the famaous Ringling Bros. And Barnum and Bailey Circus, visit many major U.S cities each year, offering a breathtaking performance in each of their rings at the same time.

The circus has changed in looks and form over the years. But its appeal is ageless and never changing. People like to see amusing acts that will make them laugh, and they like to see colorful exhibitions that require skill and daring. The circus is enterainment in its purest form.

Every age has contributed to the circus we know today. Pottery and wall drawings found in ancient ruins show acrobats and junglers. The word “circus” comes from a Roman arena, The Circus Maximus. In Latin, circus means circle or ring. In the Circus Maximus there were fats of skill and daring, such as exciting chariots races. Two forerunners of the modern cicus clown were Arlecchino (Harlequin) and Pulcinella (pierrot) of the 16th century Italian commedia dell’ arte. The trained bear, the town junggler, the court jester of medieval times all have their counterparts in the circus today.

The circus as we know it dates from the late 18th century. In 1770, Philip Astley opened a riding school in England. In the morning he taught horsemanship. In the afternoon he put on a show that included skillful riding, acrobatics, wire walking, and acts by trained dogs.

In 1792, John Ricketts established the first circus in the United State. George Washingtons was one of the many people who attended Rickett’s circus in Philadelphia. There are earlier reports of circus acts in North America, but this was the first circus in which an entire and varied prformance was given.

Cristropher Columbus found Central Aerican Indians using cacao beans for money. But he failed to discover the real treasure hidden in the dark brown, almond shaped been. This was left to the Spanish explorer Hernando Cortes.

When Cortes and his men conquered the Aztec Empire in Mexico in 1519, they dound the Indian using the cocoa beans to make a beverage called chocolatl. This early from of chocolate was very bitter, abd Spaniards didn’t like the drink until they sweetened I with sugarcane.

Cortes took cacao beans back with him to Spain, where chocolate became the special drink of the aristrocacy. The Spaniards experimented with new flavorings, such ad vanilla or cinnamon. Menwhile the art of chocolate making itself was kept a closely guarded Spanish secret.

Another 100 years passed before the other courts of Europe were introduced to the exotic drink. The elegant court of France adopted it at once. In England chocolate made its appearance in 1657 at thje first “chocolate hause”, which soon became a fashionable meeting place.

Chocolate was too expensive for any but the very wealthy, since the beans had to be ground by hand. In 1730 the invention of a machine that speeded up the grinding process lowered the price.

In 1828 C.J Van Houten, a Netherlander, revolutionized the chocolate industry by inventing a press that squeezed the rich cocoa butter out of the cacao beans. He ground the remaining chocolate into powder. This chocolate powder, or cocoa, made a smoother, less rich drink than the thick chocolate of the 18th century. Even more revolutionary., the cocoa, the cocoa butter that had been squeezed out was added to a sugar and chocolate combination and molded into bars. People began to eat chocolate as well as drink it.

But the chocolate wass still coarse and bitter. In 1876 M. D. Peter, of Vevey, Switzerland, put milk into his chocolate and produced a new flavor. A few year later final refinement turned chocolate into the smooth grained, vevelty candy of today.

Chess is the most popular war game ever invented. The kings and queens who lead thw two chess armies must face all kinds of dangerous situations. They are attacked and defended by castles, bishops, knights on horseback, and common soldiers. Eventually one of the kings is trapped and he must surrender to the other army. Every new game of chaess ia a different battle, and the two players are the generals who plan the battle.

Since its origin in India and Persia more than 13 centuries ago. Chess, the “ royal game,” has provided many exciting hour of play for both children and adults.

The word “chess” is derived form the Persian word shah, which means “king”. The term “checkmate”, signifying that the enemy king is treatened and cannot be saved, can be traced to an Arabic phrase, shah mat, which means “the king is dead”.

Many English word that are used in the game of chess, like “checkmate”, “stalemate”, ‘pawn”, and “gambit” have become important word in our everyday languange. You will find them used often by television commentators and newspaper columnist in describing political or military struggles.

Chess is extremely popular in the Russian; chess heroes there are as famous as baseball heroes are in the United State. Russian master have won many world championships since the end of World War II.

An ion is an atom or groups of atoms that carries an electric charge.
All atoms are made up of smaller particles, called subatomic particles. Some of these smaller particles carry and electric charge at all times, but the charges are not always apparent. The reason is that there are two different kinds of charges: positive and negative. The two sometimes balance each other inside the atom. This causes the atom to behave as though it carried no charge at all.

At the center of every atom is a nucleus, containing one or more particles called protons. Each of these protons has a posiive charge. Surrounding the nucleus are particles called electrons. Each of these has a negative charge.

An ordinary atom has exactly as many protons as electrons. This means that it has exactly as many positive charges as negative charges. All the charges balance, and the atom is electrical neutral.

Suppose you upset the balance by removing some of the particles. You will then produce en electric charge and form an ion. Thios process in ionization.

The particles removed are usually electrons. Protons are heavy particles in the nucleus. It is difficult to do anything to them. Electrons. However, are light particles, and some are bound rather lightly to the rest of the atom. They are easy to remove.

In fact, some electrons in atoms of metals are so easily removed that under certain condition they can be made to flow through the metal. We describe this as an electric current flowing through the metal. An electric current in emta; is actually the flowing of loose electrons.

It is possible to cause atoms to give up electrons by bombarding the atoms with energy in the form of light or heat. If an element cam be made to give off electrons when it is struck by light, those moving electrons will make up an electric currnt wherever they go. We can construct a photoelectric cell (or an “electric eye”) out of such elements.

A photoelectric cell is sometimes used to open and shut doors automatically. Light shining on the cells causes it to give of electrons. The electrons make up an electric current that causes the door to stay shut. As you approach the door, you body interrupts the beam of light. As a result, the electric current stops. The doors opens in time for you pass through.

Atoms will also realese electron is heated strongly enough. In a radio tube a metal wire is heated so that electrons are given off. The movement of these electrons can be strictly controlled because they carry negative charges. This means they can be attracted to any object that carries an negative charge. (Similar charges repel each other).

By controlling the flow of electrons in this fashion, we can make electric currents start and stop. We can direct them, strengthen weak currents, and so on. Instruments that make use of such controlled electron flows are electronic. Radio and television sets are common examples of electronic device.

It is natural for people to love their homes. From the earliest time men have decorated the places where they live to make hem as beautiful as possible. Interior decoration is therefore one of the oldest of the arts. It is also an important one, for the room you live in affect your life. The best interior decoration makes people feel comfortable and happy. The furnishings of a room are not just for show; furniture should please the people who use it and suit the way they live. Simple rooms are usually the best. If curtains, rugs, and furniture get in the way of day-to-day activities, the decoration is not successful.

The earliest interior decoration came from the desire for comfort, convinience, and beuty. The interior decoration we know with furniture, caroets, and curtains began about the time Columbus discovered America. There is a beautiful palace in Mantua, Italy, where the suite of Isabella d’Este (1474-1539), the Marchioness of Mantua, can still be seen. She had rooms designed that were small enough to be comfortable and private. They were more cozy tha the great stony halls of the palace. Palaces were built in those days to impress people with the wealth and power of the owner. They were not well suited to human needs.

It Is interesting to think about the reasons for certain furnishings. Curtains, for instance, were not hung just to look pretty, but to control light and ventilation (the movement of air).

The way thay people live effects the type of furniture they use. Early American furniture they use. Early American furniture, for example, was very study plain. The first settlers were too busy farming, clearing the wildness, and fighting the Indians to make anything but necessary and useful objects. As life became easier, frontier furniture became more graceful, for the pioneers had more time to spend on making furniture.

Many things continue to affect styles of decoration: world’s fairs, travel to other countries, scientific discoveries, and changes in architecture and building methods. Indeed, one great interior designer may start a completely new school of thought.

Insects are the largest single group of animals in the world. About 700,000 different kind of insects are known, and more are being discovered every year.

Insect are found almost everywhere on earth. Some live deep in underground caves, and some on the tops of the world highest mountains. There areinsects that live on surface of the ocean, far from land, some live in dry deser. Some live in hot springs whose water temperature is 120 degrees Fahrenheit.

Many different insects have been found in cold. Barren Antarctica. One insect is able to live in venegar. The young of another insect live in salty lakes. Insect can luve in a great many different kinds of places. This one of the reasons they have remained on earth for over 300,000,000 years.

Most insect5s are very small. Only a few kinds grow to more than 1 or 2 inches. Some are so tiny that they can hardly be seen. But the largest ones are bigger than some mice.

The small size insects makes it possible for them to escape their enemies by crawling into cracks or other hiding places. And because they are so small, they need very little food and water to live. Thus their small size is a very great advantage.

Anyone who touches the wings of butterfly or a moth finds that somethings like dust comes off on his fingers. The dust is actually made up of tiny scales. The scales grow in rows and give the wings their patterns of colors. The scales also account for the scientific name for butterflies and moths. Together they are called Lepidoptera, which means “scaly winged’.

They are about 112,000 different kinds of moths and butterflies in the world, and they live almost everywhere. In the United States and Canada there are probably about 700 kind of butterflies and 7,000 to 9,000 kinds of moths.

Borneo is a giant among the island of the world. Only Greenland and New Guinea are larger. Borneo is big enough to hold all of the states of Texas, New Hampshire, and Vermont. The island has an area about 743,000 square kilometers (287,000 square miles).

Borneo straddles the equator at the western end of the Pacific Ocean. Its neighbors to the northeast are the Philippines Islands. To the west, across the South China Sea, are Vietnam and the narrow finger of the Malay Peninsula. To the south and southwest are the large Indonesian islands of Java and Sumatra. To the east are Celebes; the fables sp0ice islands, the Moluccas; and New Guinea.
Politically Borneo is made up of the territories of three countries. Sabah (formerly North Borneo) and Sarawak are states of Malaysia. Brunei is tiny sultanate (ruled by a sultan). The third political unit of Borneo is known as Kalimantan and is part of Indonesia

The games of bowling has been played for more than 7,000 years. Object similar to our modern tenpins were discovered in the grave of an Egyptian whose burial has been placed at 5200 B.C.

Just how the sport came to be called bowling is not known. The world “bowl” may have come from the saxon bolla and the Danish bolle, meaning “bubble,” and through usage, “round’.

In its earliest from bowling was a crude recreation and was played with primitive equipment in any space thay provided suitable conditions.

Today we have automatic pinsetters and smooth, well-balanced balls and pins. We bowl in air conditioned centers amid attractive surroundings. Bowling is very popular with children and women, as well as with men. In the United States, where there are over 64,000,000 bowlers, it ranks first in popularity among participant sports.

Ice hockey, Canada’s national sport, originated in the 19th century. It is believed that the first organized game took place in 1855, when English soldier in Kingston, Ontario, played on the frozen surface of Lake Ontario. The sport quickly spread to other army garrisons and then to nearby towns.

Around 1875, students at McGill University In Montreal developed a code of rules, Familiarly known as the McGill Rules. Using these rules, teams from different cities began to play against one another, and league soon sprang up.

In 1893, Canada’s governor-general, Lord Stanley of Preston, donated a cup to be given to the country’s amateur champions. By 1896, teams were playing in the New York area. Canadian and American teams competed against each other for the first time in 1899.

The Nation Hockey Association (NHA) was formed in 1909 with four Canadian teams. Beginning in 1912, the Stanley Cup was awarded to the champions of professional rather than amateur hockey. The NHA was disbanded in 1917 and replaced by the National Hockey League (NHL). From 1926 on, the Stanley Cup has belonged to the NHL. From 1942 to 1967, there were six teams in the NHL : the Toronto Maple Leafs, Montreal Canadians, Boston Bruins, New York Rangers, Detroit Red Wings, and Chicago Black Hawks. Six more teams were added in 1967, and the league expanded further in 1970, 1972, and 1974. In 1979, the World Hockey Association (WHA), which had been formed in 1972, ceased operations. Its four surviving teams joined the NHL, raising the membership to 21 teams.

Amateur hockey has long been an important part of the North Americans sport scene. Increasing emphasis began to be placed on fairness and amateur sports in the 1950’s and 1960’s. Effort were made to provide children with the opportunity to learn and play ice hockey in supervised leagues rather than just on the local pond.

The Canadian Amateur Hockey Association (CAHA) was formed in 1914 to promote and regulate amateur hockey. Since then, it has operated country-wide junior and senior leagues. Today, it also organize leagues throughout the country for children aged 5 and up. About 600,000 players and 33,000 teams are currently registered with the CAHA.

The Mateur Hockey Association of the United State (AHAUS) was formed 1937. Originally, it had four leagues with fourteen teams. Today the AHAUS directs scores of leagues with thousands of players.

In 1920, hockey became an official sport at the Olympic Winter Games. The Canadian team won the first gold medal.

Everyone knows that water is important in our live. Without liquid water we could not live. Water also occurs naturally as a solid called ice ( and as gas, water vapor). Ice, too, is important in our lives.

We usually think of ice as something used cool beverages in summer, but it has other important uses. For example, we use it to keep food from spoiling.

Ice can also be dangerous. Ice in a frozen harbor can crush the hulls of ships. Floating island of ice the great icebergs of the North Atlantic have sunk many ships and caused much loss of life. And you know how dangerous icy road can be.

Ice from water

Let’s take the case of a small pond and see what happens as it freezes. During the summer the water becomes warmer. It absorbs heat from the sun, and it is in contact with the warm air. As winter approaches, the air temperature drops. The water then loses heat to the air, and its temperature falls.

To understand what happens next, you have to know another fact about water. It is heaviest at 40C (390F). At temperatures higher or lower than 40C, it is lighter.

As the surface of the pond cools to 40C, the water on the top becomes heavier and sinks to the bottom. When it sinks, it pushes warmer and lighter water up from below. The new surface water cools, sinks, and pushes more bottom water the surface. This circulation continues until all of the pond reaches a temperature of 40C.

When all water is at 40C, further cooling of surface water only makes it lighter. Therefore it stays at the surface. As a result, the pond starts to freeze at the surface, while the water at the bottom remains at 40C (390F).

Because water is heavier than ice, plant and animal life can survive in the water at the bottom. If ice were heavier than water, ponds and lakes would freeze from bottom. Few living things would survive in them.

Bicycling is everyone’s path to fun, adventure, and good health. It is also a very inexpensive means of tranportation. All a bicycle needs to start you down the road is the poweer of your legs.
With gasoline prices rising, may people are turning to bicycles to go to and from work. Million of children ride their bicycles to school every day. Many school offer couses in bicycling, particulary in bicycling to those who complete certain requirements.
As exercise, bicycling strengthens the heart and lungs without putting severe strain on the body. For this reason, many physicians recommend bicycling for older as well as younger people. Today the bicycle is considered a means of better health, not simply a toy or a means of transportation. And bicycling is truly fun. On a bicycle, you can see thing at a leisurely pace. You can feel the breeze and hear and aromas. This is much more rewarding than speeding along in a car.
Bicycle tours are popular in Europe, and many countries have special bicycle oaths and trails. In the United States, cycling groups such as those organized by the American Youth Hostels and the League of American Wheelmen offer supervised outing for people of all ages.

Almost all living things are made of cells. Some tiny froms of life consist of only one cell. Larger forms of life are built of many cells. That is why cells are called the basic unit of life.
The human body is made of billions upon billions of cells are probably the bacteria. These one-celled forms of life can barely be seen even with a microscope. Nerve cells are probably the largest cells. Some of them are more than 3 feet long.

The microscope has shown that all cells have three main parts: the cell membrane, the cytoplasm, and the nucleus. The cell membrane is the outside surface of the cell. Inside the membrane is the cytoplasm. This is a mass of colorless material, which hold many other tiny cell parts. The nucleus is usually near the center of the cell. It is somewhat round in shape and has an outer membrane of its own.

There are many kinds of cells. Usually each kind does one special job. For example, in animals some cells expand and contract; these are muscle cells. Other cells are sensitive to light; these cells form the retina of the eyes.

Modern microscopes show that cells are far from simple. They contain many complicated structures. And there is constant activity going on in cells.
Food and oxygen pass steadily into the cell through the membrane. The cell changes them into energy. It uses the energy to do various kind of work. The cell also makes new cell material moiré living matter. Some waste matter is left over from these processes. It passes out of the cell through the membrane. So do worn-out cell materials.

With few exception, a single cell does not live very long. But if it divides, the two new cells start life afresh. That is, intead of aging and dying, the old cell becomes two new cells.
Plants and animals grow because of cell division continues. New cells replace old or worn out cells. As cell division slows, the body ages.

Although plant and animals cells differ from each other in some ways, in a broad sense they are alike. And so we say that the cell is the unit of life.

Attacking from ambush, an African lion charges a band of antelope and strikes one down with a single sledgehammer blow of its paw. Padding sil;ently through the Indian jungle, a Bengal tiger stalk an unsuspecting deer. Crouched on a limb, a South America jaguar tenses its muscles, then springs at a passing tapir.

Like all members of the cat family, these three big cats are expert trackers and hunters. They must be if they are to eat. They belong to the order Carnivora the meat eating mammals.
Cats vary in size from beasts smaller than the domestic tabby to Siberian tigers weighing 270 kilograms (600 pounds) or more. Their coats come in many colors and many striking pattern. In the wild, cats range throughout mos of the temperate regions of the world, except for Australia, Madagascar, and some of the Pacific islands.

Have you ever watched someone looking at amgazine? What deature attracts attention first? IF the mageazine contains cartoons, the reader will probably look at them before reading the stories or articles. People often do the same when reading a newspaper. The comic strips may be amusing, but the editorial cartoon can bring a frown instead of a smile.

Because they are ussualy entertaining and because it takes only a moment to look at them, cartoons are read by nearly everyone. Cartoon have a message, funny or serious. Cartoonist know that just about every reader of the publication in which their work is printed will react to their message. Cartoons may take us laugh, but they can also make us think about important matters.

What do you think of when you hear the world "carnival"? Doyou think of a traveling show that comes to town with exciting rides and games of chance? An entertainment put on by the local volunteer fire departemenjt or some other community organization to raise money? Or a yearly clebration like the Mardi Gras in New Orleans or the winter carnivals, and they aim to provide fun for people.

The world "carnival" comes from the Latin words carnem levare, "to put aside flesh [meat])." Its seems closely related also to the Latin expression carne vale! ("flesh, farewell1"). The carnival had its origin hundreds of years ago in the feasting and marrymaking just before the beginning of Lent. (Lent is the long period of penance before Easter during which Christians may fast and eat no meat).

South of the United Stated, starting at a point about 160 kilometers (100 miles) from the tip of Florida, lie the Caribbean islands, known also as the Atilles. The Antilles from an arc stretching about 3,220 kilometers (2,000 miles) east and south to the coast of Venezuela. Between this this arc of islands and the mainland of North, South, and Central America lies the Caribbean Sea. An arm of the Atlantic Ocean, the Caribbean covers an area of about 1,942,500 square kilometers (750,000 square miles). The Panama Canal connect the Caribbean with the Pacific Ocean, making the sea a major waterway.

Named for the Carib Indians who once inhabited the smaller islands, the sea is known for its clear blue color. The temperature of the water rarely falls below 240 C (750F). Beautiful tropical fish and fascinating marine life, including many kinds of coral, thrive in the mild water. Swimming, fishing, and snorkeling are popuylar sports.

There are several hundreds island in the Caribbean. The four largest, known as the Carribean. The four largest, known as the Greater Antilles, are Cuba, Hispaniola (Haiti and the Dominican Republic), Jamiaca, and Puerto Rico. These coprise more than 90 percent of the land area are the home of over 80 percent of the inhabitans. East and south are Lesser Antilles, which are made up of the Leeward and the Windward islands. Except for fall huriricanes, which sometimes cause great damage, the climate troughout the area is pleasant. Temperatures average about 21 to 290C (70 to 850F).

Tourism is a major source of income. Sugarcane, spices, limes, bananas, oranges, cacao, and coffee are among the products grown, and most of these are exported. In the Virgin Islands and the Dominican Republic cattle raising is a major industry. Aruba, Curacao, and Trinidad produce petroleum, and Jamaica has large deposits of bauxite, a chief source alumunium.

The first canoes were most likely dugouts. These were big longs hollowed out by burning and scraping with stone tools. The world "canoe" comes from the West Indian name for a dugout. Pasific Coast Indians built oceansailing canoes out of giant cedar logs. Natines of some of the South Pacific island still make and use dugout canoes to which they fastern and outrigger (a shaped log joined by spars projecting from the side of the boat) to keep from being tipped over in heavy seas. Dugout are also found today on many tropical lakes and streams. In swamps of the southern United State dugout are called pirogues.
Early canoes were also made by stretching animals skin over light framework of flexible wood. The skin were waterproofed with a subtance like pine pitch. The Eskimo kayak, a kind of canoe, has a framework of wood or bone covered with sealskins sewed together. The top is almost completely covered to protect the paddler from the elements.
American Indian of the northeastern woodlands made canoes of birch bark stretched over a cedar frame. The sheets of bark were sewed together, and the seams were waterproofed. The result was a very light weight canoe, easy to carry overland from one stream to another. The canoes we use today are descendants of this birchbark canoe.

When you blow out of candles on your birthday cake, ou following a very old custom. People used to believe that by blowing out birthday candles they were blowing away all the bad luck of past years. That is why there is a candle for every year.

How the first candle came about is not known. Perhaps, as primitive man was roasting animals, he poked the carcass with a stick to test its tenderness. The stick covered with animal fat was easy o light and burned brightly. Thus, the torch was created. An improvement was made by dipping twigs in resin, pich, or oil to make the light last longer. Later, bundles of fat-dipped reeds took the palce or twigs and were called rushlights.

The early Egyptians made candles. Tehir funeral service were lighted and possibly perfumed by cone-shaped lumps of wax or tallow (animal fat) stuck in holders. Bands of materials that would burn were wound around the candles to keep the hot tallow or wax from spreading into a shapeless mass. The Egyptoans may also have used wicks.

Candle making slowly became and established art. The early Roman Catholic Church made special beeswax candles for their services. By the 13th century candles were in general use. In Paris and other cities candle makers traveled from door to door restocking each household’s supply of candles.

Canals are chanels or ditches filled with water. Sometimes they are natural channels, but most often they have been made by people. The earliest canal were probably dug to bring water from rivers or lakes to irrigate dry land. Other canals were used to drain water away from swampy cities and towns.
Early in history, people found another important use for canals tranportation. A canal can be used to join two cities. It can give in inland waterway in a country that has few rivers.
Natural bodies of water, such as rivers, lakes, or seas, can be connected by canals to provide shorter os safer water routes. Canals are also sometimes built in rivers that are too swift or too shallow for boats to use.
There are two main types of canals that are used for transportation: ship canals and barge canals. Ship canals are use by large seagoing vessels. Barge canals are used by cargo carrying barges and small ship.
Canals may be built all on one level, or can be opened and closed to let water in or out and let boat through.
A ship going a lower to a higher level in a canal first sails into a lock through its open lower gates. The gates are shut nehind it. Water is allowed to flow into the lock through small opening until the level of water in the lock is as high as the water in the upper level of the canal. Then the upper gates are opened, and the ship proceeds on its way. If ships must be lifted a great distance, more than one locks is used. Sometimes a whole series of locks is used, one after the other, like steps an a staircase.
If a ship is descending to a lower level, the process in simply reversed. The lock is filled with water and the upper gate is opened. The ship enters the lock, and the water is let out through small openings in the lower gate. The lower gate is opened, and the ship sails on.
Except is very small lock, the lock is always filled or emptied through small openings in the gates or through pipes in the bottom of the lock. If the gates themselves were opened to let water in or out, the water would rush in or out with terrific force. The ship might be dashed against the side of the lock and damaged. The banks of the canal might also be washed out by the rush of water.

Camping in a variety of forms has become increasibgly popular. Millions of people each year turn to the great outdoors for relaxation. There are many beautiful places-fine lakes and streams, lush montain trails, and vast wilderness areas that can be enjoyed only by those who camp. People every where are retuening to the outdoors life.

Today’s camper may be a backpaker-acamper whose wquipment is carried on the back. Or the camper may be a "trailerite," who goes with family of friends to a state park in a trailer or mobile home. Backpacker or trailerite, each is camping, and camping is now a part of our way of life.

Why? One reason is that leisure time is on the increase and families are seeking news ways to enjoy their surroundings. Parents are looking for project to involve the whole family. Money is a second reason for camping’s increased popularity. A vacation with motel and restaurant expenses can put a big dent in a budget. So an investment in camping equipment that can be reused seems to many people to be a worthwhile expenditure.

Then there is the current trend to venture forth into the unknown-to be pioneers and to live close to and with nature. Whatever their reason, campers by the millions are rediscovering their natural surroundings.

The Arabian camel is a desert animal. If necessary, it can go without food for days at a time. He hump of the camel’s back is fat. The fat serves as stored food. The camel can also go without water for long periods of time. But scientist are just beginning to understand how it does this.
The Camel is also suited in other ways to desert life. Its broad, padded feet stay on top of sand as the camel walks. When sand blows, the camel can shut its nostrils into slits. And it has thick pads on its knees. It kneels confortably on these.

The Arabian camel is sometomes called the ship of desert. Used as a beast of burden, it can carry 270 kilograms (600 pounds). Somewhat smaller camels are raised for riding. One-humped camels are sometimes call dromedaries.
Arabian camels are mostly raised in the desert of North Africa and Arabia. They all have one hump. They eat the leaves of desert plants. That belong to the big group of animals called hoofed mammals.

Another kond of camel lives on the dry, cold plains of central Asia. This is the Bactrian camel. It has two hump on its back. It also has long hair. The Bactrian camel can carry a pack over deep snow in weather that is below –180 C(00F). It can stay alive on scrub plants that few other animals would eat. People of the Asian plains raise the camel for milk, meat, hides, and hair for making cloth.

The camel’s closest relatives are four animals of South America: the guanaco, vucuna, llama, and alpaca.

A cactus (plural, cacti) is a remarkable example of the way plants have adapted to extreme conditions. Cacti hve the basic structures and processes of plants. But the work done by leaves in most other plants goes on in the stems and branches of cacti. And in the hot, dry region where cacti are among the few green plants, their spin-covered branches and stems and their absence of leaves have allowed them to survive.

The distant ancestors of the cactus had leaves and grew like the more familiar plants of today. But during millions of years the earth’s climate changed. Those parts of the Americas where the cactus ancestors grew became hotter and drier. Gradually these regions turned into desert or near desert. All this time the cactus ancestors were adapting to the changing conditions.
For example, as the climate became drier the roots of cacti gradually spread out, closer to the surface of the ground. That is why cacti quicly absorb water from the earth after a rainfall.

The water taken in trought the roots of a cactus is stored in its spongy or hollow stem. The outer layer of the plant is thick and waxy, preventing the escape of water. The outer skin is also ribbed. Some cacti have ribs that fold and expand like an accordion, depending on how much water is contained within the stem.

Although most cacti are leafless, they carry on the normal food-making activities of plants. The leaves of other plants are thin structures that contain many breathing pores; in the course of the the food-making process, water is given off to the air through these pores. But in cacti the stems and branches have taken over the work of the leaves. The thick skins have few pores, and the water is retained.

There are still some members of the cactus family that have leaves and stems like more familiar plants-the lemon vine of the West Indies is one. In most cacti the leaves have developed into spines, needles, or hairs. These growths now serve to protect the cacti-which are often the only green plants in an area-from animals.

The true cacti are native only to the Western Hemisphere. They grow mainly in the dry land of South America, Central America, and the southwestern United States, Mexico has the greatest number and variety of cacti. A few cacti have extended their ranges as far north as Canada.
In South Africa, Madagascar, and Sri Lanka there is the mistletoe cactus, a small plant that grows on trees. Probably the seeds of these plants were carried from Americas by birds. Cacti have been introduced to many parts of the world by people. ( The African desert have native plants that resemble cacti, but these are actually daisies and milkweeds that have adapted to desert life).

Boating is a fast-growing sport. Every year more young skippers pilot their craft on freshwater lakes and rivers and on the bays and inlets at the ocean’s edge. To keep pace with the rapid growth of boating, hundreds of marinas have been built to provide shoreside berths for small craft. Marina is a Spanish word meaning “seacoast,” and is used in English to describe a modern boat basin with piers and slips for docking boats, launches, and yachts. In a marina large and small boat are repaired, serviced, and stored. Shore electricity, telephones, fresh water, ice and fuel are available at docside. Here pleasureboat owner may shop for supplies and food and drink a;; within walking distance of their boats. Every type of craft may be seen at a marina. There are sailing dinghies and twp masted schooners, outboard runabouts and big cabin cruisers with berth for six or more people.
The 4.2-to 5.5-meter (14-to 18-foot) run about are the most popular small powerboats. They are wonderful for fishing or for just having fun on the water. The larger ones, fitted with powerful outboard engines, are used for towing water-skiers.
Before beginners learn to run one of these craft or even go for a ride in a dinghy or other small rowboat, they should know the basic rules of safety for themselves as well as for their boat.

Bird are flaying animals. That it the single most important fact about them. Bird are not the only animals with the power of flight insect and bats fly; so did certain ancient reptiles. But birds are the only really numerous flaying animals that have backbones. There are about 8,600 species of bird, but fewer than 1,000 of bats. The flying reptiles have long been extinct. And insects do not have backbones.
Flight is a very difficult activity for a living thing. The strains and streses on the bones and muscles of a flying animal are tremendous. Its senses, such as those of balance and sight, must be of a special sort. Flying demands a much greater supply of energy than do most forms of getting about. Therefore birds have very special features and abilities.
For instance, only a very light animal can fly, but its supporting framework must be very strong. A bird skeleton is a simple, stiff frame work that is both light and strong.
It is light because most of the bones are thin plates or hollow, air-filled tubes and struts.
It is strong because many of these bones have special shapes; the shapes give the bones their strength, rather than the weight or thickness of the bones.
A flying animals also needs strong but flexible surfaces for wings. Feather fit this need perfectly. Overlapped like shingles, they also serve as the warmest yet lightest of insulators for these warm-blooded, flying animals. Fetahers are found only in the group of animals we call birds the class Aves.
The forelimbs (or arms) of bird serve as wings. This means that they are of little use for anything except flying. So birds must walk on two legs. They must have very flexible necks and strong beaks to care for yopung, as weapons of defense, and for many other jobs tha non flying animals do with the paws, claws, or hands on their forelimbs.

There are many variation of billiards. However, the basic skills and equipment are much the same in all. A white cue ball is struck with a stick, or cue, so as to roll across a level table top and strike other balls. The two most popular versions are pocket billiards and three cushion billiards.
Few sports have the blue-blooded lines of billiards. There is evidence that the game developed as an indoor version of lawn bowling in England, about 600 years ago. Shakespeare mentioned the sport, and Mary Queen of Scots was a noted wielder of the cue. The world “billiard” comes from the Old French billart, meaning “playing stick,” or “cue”.
Spaniard are said to have brought a billiard table St. Augustine, Florida, in 1565. The game matured in America, where championship matches became popular during the late 1800’s. Billiards lost some of its popularity with the coming of motion picture and other attractions in the 20th century. Today, however, it has found its way back into the hearts of hundreds of thousands. Much of this new rise in popularity can be attributed to intoduction of the home billiard table.
Another factor is the bowling alley that includes billiards in an ultramodern setting with games for all the family to enjoy.

Bermuda is a sunny group islands in the vast Atlantic Ocean. The nearest land is Cape Hatteras, North Carolina, about 1,075 kilometers (670 miles) to the northwest.
The islands are British colony known officially as the Bermudas or Somers Islands. The total land area is about 54 square kilometers (21 square miles), and the length of the island chain is 35 kilometers (22 miles). The land is shaped like a giant fishhook.
Nature wa symbolic when it shaped Bermuda this way, for the islands are noted as a superb fishing area. Naglers have caught bonefish, wahoo, and tuna of record size Bermuda waters. Over 600 species of fish have been found along the reefs and in the open sea around Bermuda. The Bermuda Government Aquarium has one of the world’s finest collection of tropical marine fish.

They are probably 15,000 to 20,000 different kind of bees living today. Ninety-five per cent of these various kinds are solitary bees that live alone. Five per cent are social bees that live together in colonies containing hundreds, and in some cases, thouands of members. The most social bee of all is the honeybee. It has developed a most efficient social system. Thousand of honeybees live co-operatively in hives and devide the labor of the colony.

Beavers inhabit ponds and streams in wooded areas from Alaska to northern Mexico. Their bodies are ideally constructed for their varied activities on land and the water. A beaver’s large hind feet are webbed for swimming. His broad, flat tail is scaly and naked, except for a few bristles. It seves as a prop when he stands up to gnaw on tress; it becomes an alarm signal when slapped against the water; it is rudder and an oar when he is swimming.
Though air breathers, beavers are troughly at home in the water. They can remain submerged for 15 minutes at a time. When a beaver dives, flap-like valves in his ears and nostrils close, shutting out the water. Except for his tail, the beaver is clothed in a shiny coat of soft, thick underfur; this is overlaid with longer, coarser guard hairs. Glands on either side of the tail supply oil, which keeps the coat waterproofed and glistening. The two inner claws of the beaver’s hind feet are grooved; they make efficient combs for grooming the coat and spreding the oil through it.

A shaggy giant wades into a stream. Ducking its head, it lunges forward. Then it comes up, a big salmon flopping between its jaws. Triumphant, the huge beast clambers ahore to eat its meal in comfort. This expert catcher of fish is the Alaskan brown bear the world’s largest land dwelling flesh eater. It may be nearly 3 meters (about 9 feet) long.
Alaskan brown bears feed almost entirely on fish when salmon are running upstream to spawn. T other times the bears make a meal of whatever is in season and available. They may dig for roots and bulbs and eat berries, fruit, eggs, and insect. They burrow after squirrels and other small mammals. Sometimes they even eat grass.

A battery is a source of electric current. There are several kinds of batteries, and they come in many size. But they all work on the same principle-they change chemical energy direcly into electrical energy.
A battery is made up two or more units called cells. Sometimes a number of cells are packaged together, as in the battery of a portable radio. Sometimes each cell is separate, as in the ordinary flashlight. That is, what most people call a two-battery flashlight is realy a two-cell plashlight. A single cell can produce electric current, but in many cases it is more practical to use two or more celss and get a greather electrical “pressure,” or voltage. In a two-cell flashlight, each dry cell has a voltage of 1.5. The whole battery ha a voltage of twice that amount, or 3 volts.

In the animal kingdom bats are classed as mammals, a large group that includes men, mice, lions, and dogs. Like all mammals, bats nurse their young on milk. Like most mammals, they have hair and bear living young. But in one ways bats are different from all other mammals: bats can fly.

There are mammlas knows as flaying squirrels and flaying lemurs, but they do not truly fly. Rather the glide from tree to tree. Bats are the only mammals that move through the air with wings.

A bat’s wings is not like a bird’s wings. The bird’s wing is formed chiefly of feathers; these grow out from bones that make the front edge of the wing. The bat;s wing is a double layer of skin stretched over the thin bones of its arm and fingers. A bat’s wing is something like a kite.
A bat’s skeleton is the framework for a living flying machine. The arm extends from a shoulder socket, bends at the elbow, and ends with long, slender fingers. The fingers are almost as long as the rest of the body. They support the main part of the wing and are webbed. These webbed fingers account fior the bat’s scientific name, chiroptera, meaning “wing-handed.”
The wing covers all fingers except a short thumb, which is left free. A sharp claw on the end of the thumb forms a hook at the top of the wing. When its wings are folded, the bat uses its hooks to climb tree trunks, rocky walls, and other rough surfaces.
The skin connecting the webbed fingers is also attached to the bat’s clawed feet. This makes the back part of the wings. Most bats have an extra flap of skin connecting their feet. While flaying, many can fold this flap into a pocket for cathing insects.
Since its legs bones and leg muscles are included in its wings, a bat can fly more easily than it can walk. But the feet are far from useless. Like human hands, a bat’s feet can turn inward, which enables them to grasp objects like twigs, and branches. Sharp claws hook securely into crack or around bumps in the wall or ceiling of a cave. These claws are so strong that they support the bat’s whole weight, even during sleep.
When resting, a bat can use its claws to cling to a wall or tree trunk-or it may hang upside down, suspended by its feet. Bats hang upside down because it is easier for them than perching upright. Their small legs are attached to the body in a way that makes perching in awkward.

Basketball in one sport that can be called truly American. The man who invented it, Dr. James A. Naismith, was born in Canada. But he developed the games in the United States, and it is there that basketball has become a popular winter indoor sport.
Two teams, of five players each, play the game on a court. At each end of the court is a basket attached to a backboard. The bright orange metal rim of the basket is 46 centimeters (18 inches) in diameter and is placed 3 meters (10 feet) above the floor. From it hangs a white cord net. The objective of each team in a game is to scaore points by throwing the ball into one of the baskets.
The basketball is a rubber bladder inflated with air and covered with an orange or natural tan leather or composition cever. It is round, about 75 centimeters (30 inches) in circumference, and weight between 565 and 625 grams (about 20 to 22 ounces).
In 1891, when he invented basketball, Dr. Naismith was an instructor at the international Training School og the Young Mens’s Cristian Association (YMCA) in Springfield, Massachusetts. It wa winter, and he noticed a lack of interest in formal gymnasium exercises among some of his students. What they needed, he thought, was a fastaction game that could be played indoor when the football season ended. He decided that some kind of game in which players wouls have to throw a ball into baskets would be interesting. So he attached a couple of old peach baskets to the ends of the gym balcony.
In the early day soccer ball was used. Every time a gola was made, someone had to climb a ladder to get the ball out of the basket. A a while wire mesh basket were used. In 1906 the metal hoop similar to that of today was used for the firs time. At first when a basket was missed, the ball would go into the crowd. This caused much delay. Than backboard were put up so the ball would bounce back into the playing court.

When the game was first played, nine people formed a team. Later it was changed changed to to permit nine, seven or five to play. Tosay five players make up a team. Then, as now, running with the ball, pushing, and tripping were not allowed. The early scoring rulus allowed 3 points for each basket. The center jump was used to start play after every goal. And when a ball went out of bounds, the first player to get it would put it back into play.

Basketball has come a long way since Dr. Naismith hung those two peach basket in the Springfield YMCA gymnasium.

Today it is a major winter sport in school colleges, YMCA’s, and club troughtout the United Stated anda Canada. It is played outdoors and indoors by boys and girl, men and women. Thoussand of people crowd into gyms and sport arenas to watch tournaments and championship games. On a makeshift court in the back yard or the polished hardwood floor of an arena, basketball is a great game whether you play it or merely watch.
Several Canadian were among Dr. Naismith’s pupils, and through them basket was introduced in Canada. Other YMCA leaders and America armed force abroad helped to spead the popularity of the game in Latin America, Europe, The Philipines, China, and Japan.
In 1961, on the 100th anniversary of the birth of the inventor of basketball, the cornerstone was laid for the Naismith Memorial Basketball Hall of Fame in Springfield.

Baseball is called the great American game. Hardly a child in the United State has grown up without playing it. The game is also popular in Canada, Mexico and other parts of Latin America, Japan, and other countries in Asia.
The game is so much a part of American life that its term have been adopted into the everyday speech of the people. “Pinch-hit,” “going to bat,” and scores of other baseball terms are used even by people who are not well acquaninted with the game.
During World Awar II Germans dressed in American uniforms turned up behind the American lines. Many of them spoke English very well and could pass as American soldiers. But the United States Army found a way to tell which were false and which were real Americans. They halted strange soldiers at checkpoints anda asked them question abiut baseball and some of its star players. Guenine Americans, who couldn’t, were promptly made prisoners of war.

The air around you is heavy. It has weight. There is a ton of air over each square foot of the earth’s surface. There is a name for the air’s weght pressing down on the surface of the earth. The name is air pressure. A barometer is an instrument that can measure this air pressure.
You may have seen a barometer hanging on a wall. In it there is a small box, or chamber, with thin metal walls. Most of the air has been drawn out of this chamber. The thin walls move it or out slightly when there is an increase or decrease in the air pressure outside. A pointer on the front of the barometer is connected by a lever to the chamber walls and shows these small changes. The pointer moves in front of a dial that is marked off in units of air pressure. The units are usually inches of centimeters.
Air pressure is important in wheater forecasting. A change in air pressure usually means change in weather. A drop in pressure often means that bad weather is coming. A rise in pressure ussualy means that clear weather is on the way. Ship and airplanes carry barometers. Weathermen use barometers in making their forecasts.
Air pressure alse changes when you move from sea level to higher altitudes. When you climb a mountain, you find that the air grows thinner. It weighs less, and so it presses down less strongly. Air plane pilots often use barometers called altimeters to tell them how high they are above the ground.
The barometers you have read about so far are called aneroid barometers. Aneroid means "without liquid"." There are other barometers that do use liquids. The very first barometers was of this type. An Italian scientist named Evangelista Torricelli (1608-47) designed it closed at one end and filled it with mercury. He turned this tube upside down in a pan that contained more mercury. The mercury in tube started running out, of course. Soon the mercury stopped running out. The weight of the mercury in the tube was balanced by the pressure of air on the mercury outside.
Mercury barometers are still used today. Scientists read a mercury barometer by seeing how high the column of mercury in the tube is. When air pressure increades, the mercury column goes up. When the pressure decreases the column goes down.
Mercury barometers are very accurate. But they are clumsy to move around, and they have to be kept upright, so that the liquid stays level. That is why ordinary barometers in homes or on ships and airplanes are aneroid barometers. Mercury barometers are used mainly in scientific laboratories.

A ballet is theatrical entertainment combining dance with other art forms, usually stage design and music. It many tell a story or merely depict an idea or mood. Ballet is a French word that comes from the Italian ballo, "a dance."
The Ecercises, or techniques, of ballet are designed to display the human body in the most elegant and harmonius way possible. Ballet technique is strict, and the training is strenuous. But the result on stage is natural and beautiful. Ballet is nerly 500 years old. Yet it is very young compared with dance itself, which began with primitive people. Ballet began in Italy about the time of Columbus’ voyages to America. It was quite different then from what it is today. At that time ballet was a court entertainment for the amusement of the nobility at lavish balls and banquets. Dancing, music, pantomime (acting without words), petry, and drama were combined. The first ballet dancers were the royalty and nobles of the court, since there were no professional dancers. The steps were modeled on the elegant but rather simple social dances of the day.
Ballet as we know it is the product of many countries. The French organized the technique and gave it liveliness. The Rusian added strength and passion. The English gave it delicacy and tenderness. The Americans gave it speed and variety.

Badminton is a fast game played with racket and a shuttlecock on a wood, dirt, or grass court. The court is somewhat like tennis court, but smaller. The shuttlecock, often called simply the shuttle, or "bird," is hit back and forth over a net 5 feet high. It must be returned before it strikes the court. The game can be played by two persons (singles) or four person (doubles). It is a very adapted game and can be played both indoor and outdoors. Offical tournaments are played indoors. The outdoors game more suitable for family enjoyment at home.
Badminton develop from Battledore and Shuttlecock, an ancient game that was popular with children. There are several explanation of how the modern game began; one is that about year 1870 English army offivers brought a version of it to England from India, where it was called Poona. The new game took its name from the Duke of Beaufort’s estate, Badminton, where the game was probably played indoors for the first time. Badminton became popular in England, and in the 1890’s the Badminton Asscociation was formed. In 1934 the International Badminton Federation was organized.
There are two international badminton championships; the Thomas Cup competition for men, which began 1948, and the Uber Cup for women, which began in 1957. Malaysia and Indonesia have dominated the men’s event, and the United State and Denmark the woment’s competition.

An early from of banking was the money lending carried on in Florence and other northern Italian cities during the Middle Ages. In fact, the world "bank" comes from the Italian word banca, meaning the "bench" or "counter" on which the money was displayed.
As trade flourished in Italy and trought out Europe, money became so important that ways to protect it and handle it wisely had to be found. In the 17th and 18th centuries, commercial banks were set up. Before that ways, it was not easy for people to find safe places for their money. Thefts or fires could deprive people of all their savings.
The early European commercial banks were privately owned. Their chief business was to help merchans finance trading activities. These banks accepted deposits of money, collected bills for sellers. And acted as exchanges house for converting the money of one country into the money of another. They also extended loans to their depositors to help them pay for shipping and storing their wares.
Some of these private banking establishments were owned by individual families. The famous Medici family, which ruled Florence for three centuries, got its power and influence through the bank founded by Giovanni de’ Medici in the 14th century.
One of the most interesting and successful family banking enterprises was the House of Rothschild. The founder was Meyer Amshel Rothchild, who started as a moneylender in Frankfurt, Germany. In the second half of the 18th century, Rothschild’s shrewdness and good financial sense made the firm a solid success. In addition to the frankfrut office. Offices were opened in London, Vienna. Paris, and Naples. Each office was directed by one of Rothschild’s five sons. Close co-operation among the five branches, together with shrewd but honest business dealings, soon made the Rothschilds extremely wealthy. During the 19th century the Rothschilds became famous as moneylenders to European governments.
Alarge portion of the business of early commercial banks involved foreign trade. Thus banks naturally came to be located in important seaport cities. These cities such as London, Amsterdam, and later, New York became the first financial center. They have continued to banking center.

The banana isi a tropical fruit. People used it as a food even before history began to be written. The armies of Alexander the Great found bananas growing in India in 327 B.C. No doubt they grew there long before that time. Because of an old story that the sages of India rested in the shade of the paklnt and ate its fruit, the banana is often called the "fuit of the wise men".
Plan scientists believe that roots of banana is plants were carried to the east coast of Africa by a people who moved there in ancient times. From there the banana plant was carried across the African continent to the Guinea Coast by early Arab Traders.
When Portuguese explorers discovered the Guinea Coast of Africa in 1482, they found bananas growing there. These explorers took roots of the plant, and its African name, banana, to the Portuguese colonies in the Canary Islands. The nest step in the journey of the banana plant wa across the Atlantic Ocean to the New World. In 1516, only a few year after Columbus; famous voyages of discovery, a Spanish missionary brought this useful plant to the Caribbean island of Hispaniola. Other missionaries followed his example and planted bananas on the the other islands of the Caribbean and on the tropical mainland. Thus, the banana plant had to go more than halfway around the worls to reach Central America, where so many of the world’s bananas are grown today.
It was not untiul the latter part of the 19th century that banans were brought into the United States in quantities for sale in stores. Before that time, very few Americans other than those who had traveled in tropical countries had ever seen or tasted a banana. Even after banana schooners began entering New Orleans, Boston, and other ports, only people who lived in or near the port cities were able to eat bananas. The banana is perishable. Unlike some other fruits, it cannot be stored. Within a period of ten to twenty days, bananas must be harvested, shippes several thousand kilometers, ripened, and sent to the stores where they are sold. Today’s modern transportation-fast, refrigerated ships, train, and truck makes it possible for families in Chicago, in the United States, or Calgary, in Canada, to eat bananas every day of the year.

Everyone loves a band. No football game, parade, circus, or Fourth of July Celebration be quite complete without a rousing march. Not only does everyone love to hear a band, but almost everyone loves to play in one. In the United States alone there are millions of people who play in bands now or who have palyed in school, college, or town bands.
The world band is a broad term that describes a groups of musicians performing on wind and percussion ainstruments. One thinks immediately of a brightly uniformed marching band, perhaps part of an army or navy unit or the band of college or high school.
Aside from marching bands that entertain at fairs, public ceremonies, and informal social gatherings, there are other bands that exist only to perform music in a concert, just as an orchestra does. Such bands are known as concert or symphonic bands, or wind ensembles. What all bands have in common is that they are composed of wind and percussion. Band usually have at least 50 palyers.
Since band often perform out-of-doors, they require instrumens whose sound carry easily. Trumpet, trombones, tubas, horn, drums-all are instruments capable of making plenty of noise with little effort on the part of the player. The large family of woodwinds, icluding clarinets, oboes, bassoons, and flutes (and their relative, bass clarinets, English horn, saxophones, and piccolos), also has this advantage.
A second requirement is that the instruments be easy to carry. It is impossible to march while playing a cello or double bass; even the violin is not easy to play while one is walking. But one can easily play brass and woodwind instrument while marching. And of course the band has always required instruments that cerate the proper military excitement. For this the brass and percussion instruments are perfect.
There is a special type of band called a brass band. As its name implies, it uses only brass instrument and no woodwinds. Many excellent Salvation Army bands are of this type. They usually have 24 players and produce a good, well-blended sound despite their limits of tone quality and range.

Early in the 18th century Bartholemeu de Gusmao, a Portuguese priest, developed a samall hot-air balloon. But the first big balloon was built by two French brothers, Joseph Michel and Jacques Estenne Montgolfier, in 1783. They made a huge bage of paper and cloth, which they held over a fire. When they released the smoke-filled balloon, it soared into the sky.
Encouraged by their success, the Montgolfier brothers build a balloon with a basket underneath to carry passengers. In the basket they put a rooster, a duck, and a young sheep. The balloon was filled with hot air from a fire and was released. The basket, with iis animal passenger, floated upward. High above the earth the warm air inside the balloon cooled off, and the balloon slowly floated to earth. Live passengers had been carried into the air and returned safely for first time in history.
This feat inspired two men to become the first human beings to fly above the earth. They were Jean Francois Pilatre de Rozier, a French physician, and Francois Laurent, the Marquis d’Arlandes. A huge blue and gold hot air balloon carried them aloft over Paris on November 21, 1783.
Fire was always a danger at these early balloon launchings. One spark could send a balloon up in flame. But in the same year that the hot air balloon was developed, Jacques A.C Caharles. A French scientist, invented the gas balloon. Charles build a sphere of rubberized silk and filled it with hydrogen, a gas that is lighter than air without being heated. The balloon soared into the air and landed in a field near Paris, where it was destroyed by frightened farm workers.
With to help of others, Charles later developed a balloon thay could carry passengers. To rise higher, the balloonist released sand from bags tied to the side of the basket. To come down, the balloonist pulled a rope that opened a valve located at the top of the balloon. The open valve allowed hydrogen to escape, so that the balloon would slowly deflate and return to earth.

Bacteria are probably the most common form of life on earth. They are also among the simplest and smallest living things. They are micro-organism, which mean they can seen only under a microscope.
Some bacteria cause disease, but most do not. There are at least 2,000 species of bacteria. Most of them are harmless or helpful to other forms of life, including people.
What is bacteria live?
Bacteria are everywhere. Some live in the mouths, and intestines of animals and of people. Other live on fallen leaves or animal waster; in water, milk, and most food;and on dust and soil. Some bacteria can use hydrogen gas, ammonia, and iron compounds as their food. A few bacteria feed on gases and acids that are poisonous to us.
Most bacteria are killed by heat, yet there are a few kinds that live in hot springs, Freezing does not usually kill bacteria, but it checks their growth. Some kinds of bacteria, but resist drying, strong chemicals, or extreme temperatures by changing into tough-walled spores. The cabteria may last a very long time in this resting form. Under favorable condition, the spores walls burst, and the bacteria become active again.
New and future uses of bacteria
Scientist are finding many ways of making bacteria work for the benefit of people. For example, they have developed a method for producing methane gas by processing the manure (solid wastes) of cattle. Methane is valuable fuel. Like natural gas, it is used for heating homes and factories, and for other energy needs. In the same process, protein and minerals are extracted to be used for cattle feed. Protein rich cattle feed has also been obtained by growing bacteria on wood petroleum, abd sewage wastes.
Some bacteria are used as living insecticides against certaian insect pests.
Scientists are experimenting to find answers to questions such as these; May bacteria useful in fighting other bacteria able to make cellulose, which can be used to make paper? Can bacteria that eat holes in underground deposits of limestone be used to make oil flow more easily? Can bacteria be used to generate electricity? While feeding on certain subtance, some bacteria produce energi that can be converted to electricity. Scientists are traying to devise batteries that can use bacterial energy.