Where have Seven Wonders of the world gone?

We have often heard about the seven great wonders of the world. Would you like to know what are these seven wonders? They are: The Pyramids of Egypt, The Hanging Gardens of Babylon, The Tomb of Mousolus, The Temple of Diana, the Colossus of Rhodes of Helios,

The Statue of God Zeus and The light House of Pharos near Alexandria. Out of these seven wonders, the Pyramids of Egypt are preserved only. The story behind their construction is very interesting.

The only preserved wonder-The Pyramids of Egypt were made some 5000 years ago. In fact, these are the tombs of the Egyptian ruler. The biggest pyramid is located at Gizeh, a small town near Cairo. This is the tomb of Pharaoh Cheops and his queen. Its area is 750 sq.ft. Its base forms a square and its height is approximately around 451 ft. 2 million stone slabs are fitted in this tomb. It is said that it was completed by more than one lakh labourers who worked for 20 years.

The second wonder was the hanging gardens of Babylon. Around 2500 years ago, the king of that place, Nebuchadnezzar made beautiful gardens on the walls on all sides of a palace to fulfil his queen's wishes. These gardens were quite high from the normal surface and they had to be watered by hot water. Up to the year 514 A.D., these gardens were intact, but Persia attacked Babylon that year and destroyed these walls and gardens.
The third wonder was the tomb of Mousolus, theruler of Halicarnassus which was constructed by his queen after his death. This was approximately 30 metres high and had on its top statues showing the king and queen riding a horse driven chariot. Within a short period of its construction, this tomb was demolished in the attack by Alexander the Great. Later in 1857, an English traveller went there and brought back wth him the statueof the king which is still preserved in the British museum.

The fourth wonder of the world was the temple of Diana at Ephesus with its roof resting on 19 metres high pillar. This temple was constructed in the year 350 B.C. in Eastern Turkey. At that time this temple was considered so sacred that people would feel secure after depositing their wealth and precious possessions in this temple. In the year 262 A.D. Goths burnt down this temple.

The fifth wonder of the world was a bronze statue colossus of Rhodes of Helios. Approximately 30 metres high, this was located at Rhodes island. This was constructed in the year 280 B.C. but 56 years after its construction, this statue was destroyed in an earthquake.

The sixth wonder of the world was the statue of God Zeus situated at Olympia. This was made by the famous sculptor Phidias in the year 450 B.C. The clothes of this 9 metres (over 30 feet) high statue were made of gold. Its body was made of ivory and the eyes of precious diamonds. This statue was destroyed by the followers of Christianity.

The seventh wonder of the world was the famous light house constructed in Pharos, a peninsula near Alexandria, Egypt. The tower of white marble was completed about 280 B.C. From pictures it seems to have been over 120 metres high with a ramp leading to the top where a beacon was kept during day and night. It remained standing until the 12th cent. A.D.

Read More

How was the calendar started?

In the beginning of the civilisation, when man observed the sun rising and setting, he felt the occurrence of the day and night. The idea of the month came with the observation of the phases of the moon. And probably the change in the seasons gave birth to the idea of the year.
Finally with the development of science, man came to know things more correctly. He defined the period of one revolution of the earth round the sun as one year. The time taken by the moon in completing one revolutionroundthe earth was called a month and the time taken by the earth to complete one rotation on its axis was called a day.
In the initial calendars of Egypt, one year used to have 12 months, with one month having 30 days. The extra days were added to the year in the end to make it exactly equal to 365 days. The people of Greece used the lunar calendar according to which an additional period of three months used to be added to every eighth year. In the year 432 B.C the astronomer Meton found out that 235 lunar months exactly fit into 19 years.
The first major step in the direction of the development of calendars was taken by the Roman ruler Julius Caesar in 46 B.C. He took Greek astronomer Sosigenes help in this work. this calendar was based on the timetaken by the earth in completing one revolution round the sun. this was named as the solar calendar. the earth completes one revolution round the sun in 365.25 days, hence this period was taken as one year. The astronomers of Caesar defined a year as consisting of 365 days and every fourth year consisted of 366 days so that one-fourth of a day left out every year was compensated in thefourth year. this fourth year was called the 'leap year'. Any year divisible by the number 4 was taken to be a leap year. 365 days of the year were divided into twelve months. The months January, March, May, July, August, October and December consisted of 31 days each, while April, June, September and November consisted of 30 days each. The month February was taken a consist of 28 days, whereas in the leap year it would have 29 days. This calendar continued for 1600 years. However, later a mistake of 10 days was detected in these calculations, because the earth actually takes 365.2422 days to complete one revolution of the sun. As such it was natural that a difference of 7.8 days should have taken place over a period of 1000 years. To remove this deficiency, Gregory made an improvement in 1582 according to which the century years (100,200,300 etc.) Which were not divisible by the number 400, would not be made leap years i.e. February month would contain only 28 days in such century years. Accordingly the years 1700, 1800, 1900 had February of 28 days only, but the year 2000 would have February of 29 days. This is called theGregorian calendar and is in use all over the world.
The second calendar in use is the lunar calendar which is based on the movement of the moon. Since the moon takes 29 1/2 days to complete one revolution of the earth, it takes 354 days (29 1/2 * 12) for twelve such revolutions. As such the lunar year, consisting of 354 days, in less than the solar year by 11 days. This way a difference of 33 days occurs in every three years. This difference is removed by making every third lunar year consisting of 13 montsh. This additional one month is called 'Malmas' in Hindi. To make up for the days of the month, theactual numbering of the lunar days is advanced or deferred for the necessary adjustment. On 22nd March, 1957, the Government of India introduced the Shaka Calendar based on the lunar System as the Official Calendar. The Shaka era is behind the Christian era by 78 years.
In addition to these two calendar, some countries have other kinds of calendars also, which are used by them for religious purposes of those countries.

You have already read that while making the calendar, the 365 days of a year were divided into 12 months. These months have been named as January, February, March, April, May, June, July, August, September, October, November and December. Do you know how they got these names?

    January is the first month of the year. It's name originated from the Roman god Janus' name. The Romans think that this god has two faces-one for seeing into past and other into future.
    February is named after the Roman festival Februa.
    March is named after the warrior god of the Romans Mars.
    April is probably derived from the Latin word Epirer which means'to open'. Since the         spring season falls in this month and there is blossoming in trees and         plants, this month has been named April.
    May is derived from the Roman goddess Myma's name.
    The origin of June is not definitely known but probably this has been derived from the name of Juno-the goddess of heavens.
    July is named after Julius Caesar, who was born in this month. He was the first man who made big contributions to the development of the modern calendar.
    August is named after king Augustus of Rome who had won many victories in this month.
    September finds its origin in the Latin word 'Septem' meaning 'seventh'. This was the seventh month in the old Roman calendar.
    October comes outof theRoman word 'Octo' meaning eight. In the old Roman calendar this was the eighth month.
    November originates from the Latin word 'Novem', meaning nine. This was the ninth month in the old Roman calendar.
    December is derived from the Latin word 'Decem', meaning tenth. This was the tenth month in the old Roman calendar.

Read More

How was the needle invented?

Needle is a tiny thing, but is really very useful. Had there been no needle, we would never have got our clothes stitched. It has been serving the mankind for thepast thousands of years. The excellently stitched clothes you see today speak of the marvel of the needle. Not only this, millions of people earn their livelihood in the world with the help of the needle.

We do not have definite information regarding the invention of the needle. But this much is certain that in the early stages when man had started covering his body with barks and hides, he would have felt the necessity of the needle to stitch them. And naturally he would have made some needle-like thing to do this job. In ancient times, needles were made from bones, ivory, wood, bronze and thorns. These needles were very ugly and had no holes at the end. For several hundred years man used needles made from bones. These were provided with holes at one end.
Chinese were first to manufacture steel needles. From China these needles reached Europe. This way production of steel needles was started in Nuremberg (Germany) in the fourteenth century. During the reign of Elizabeth I, a person named Elias Grouse of Germany taught the making of needles to the people of England. Now needles are manufactured in every country of the world. England and France stand first and second in the manufacturing of the needles respectively. Even though the needle is a very small thing and machines are used in its production, yet the needle passes through the hands of twenty people during the production stages.
On the 20th March 1971, a girl studentof Wistershire (England) established a world record of inserting thread in the hole of an extremely small needle 3795 times in two hours. The record is still unsurpassed.

Read More

How was the circulation of currency started?

Generally the word currency denotes conins and paper notes issued by a government for buying an article. Today currency forms the basis of all the trade in the world.

In the beginning of the civilisation, whenever somebody wanted to buy anything, he would barter it with food grains, tobacco, hides, salt etc. In villages and under-developed countries this system is still prevailing. It is known as barter economy. Such a system used to cause lot of inconvenience to people. Thus, to overcome this difficulty, man started using gold and silver bars. However, it was not possible to determine the purity and value of these metals.
Around 700 B.C, King Gaijes of Lydia (today's Turkey) started coins' circulation made from an alloy named 'electrum'. This consisted of 25% of silver and seventy-five percent gold. These coins were shaped like beans. And when Greeks came across these coins, they found them very useful in their day-to-day business. They also started using such coins. In a very short period, this systembecame popular in many countries of the world. Later, gold and silver coins were replaced by copper coins.
The use of coins solved many problems, but their use in larger quantity proved inconvenient because of their weight. As a result, currency notes were invented. The Chinese were the first to use paper currency. They started its circulation around 119 years B.C. The notes were circulated bya a bank which used to guarantee the payment of the amount mentioned on these notes. In the modern time Stockholm's Bank of Sweden was the first to issue currency notes in July 1661. Today along with notes, even cheques have come into use. In this way, facilities for monetary exchange have considerably improved. In India the first note was printed during Sher Shah Suri's reign.

Read More

Why is the census taken?

Census operation is now common in almost all the countries of the world. Nothing can be definitely said as to how and when it was started. But it seems that man realised the importance of census when he started living in larger groups. It is said that the population of the world was 85 million in the year 4000 B.C.
It is evident from this fact that the system of census was very much developed at that time also. After all, why is the census taken? The reasons for this have been different at different times. In ancient times, the king used to have census with a view to assess the number of people fit for fighting in wars. Another purpose for having census was collection of revenue. Previously, there were probably these two main reasons for conducting census, but now it has acquired greater importance.
Census helps in presenting a clear picture of different aspects of population. This helps the government in the preparation and execution of plans relating to education, health, employment etc. Census tells whether the population is increasing or decreasing. The knowledge of rate of birth helps in the formation of plans to cater to the needs of people in future. It also gives the ratio of urban to rural population. It is also helpful in holding elections, because it is on the basis of population only that the number of voters is fixed. Besides, census helps very much in improving law and order, economic, social and other conditions too.
The first census in our country was conducted in 1872. Since then it has been repeated every ten years. the latest has been the census of 1981.

Read More

How are the pearls formed?

Pure pearls are very precious. You will be surprised to know that these are made by a small sea-creature, oyster. This can crawl on the ground also. The biggest tragedy with this little creature is that fish of the sea or the bigger members of its own family eat it away. When the oyster comes to the sea shore to save its life man eats it. In order to protect itself, it forms a hard shell around its own body. Pearls are made within this hard cover.
The discovery of pearls is an interesting story. Around four thousand years ago a Chinese was suffering from hunger. To quench his hunger he opened some oysters to find some eatables. Inside on oyster he found one round shining small ball. This shining thing was later on called pearl.
Whenever by chance a sand particle goes inside the shell of an oyster, it starts depositing layers after layers of the shell material on this particle. These layers are made up of calcium carbonate. After some-time the formation of the pearl inside the shell is completed. The pearl so formed is round, white and shining. This is called pure pearl. However, the pearls are not essentially white only. Their colours may be black or pink also. Man has now developed some techniques of making artificial pearls. Under these techniques sand particles are introduced inside the shell. After two or three years, when the shell is taken out of water, a pearl is found inside it. These pearls are called cultured pearls. Since pure natural pearls are very costly, generally we purchase pearls developed by these artificial techniques. On the 7th May, 1934 a pearl was found in Phillippines measuring 23 cm long with a diameter of 13 cm. This pearl weighed about 6 kg.

Read More

What is rubber?

The history of rubber is as old as that of nature. Rubber is obtained from special type of plants. Three million years old fossils of the rubber producing plants have been found. It is a highly elastic organic material. It can be stretched eight times to its original length. A while liquid called latex comes out of the trees from which the rubber is made.

When this liquid is dried up we get rubber. Rubber so obtained is called natural rubber. In fact, there are more than four hundred kinds of plants from the juice of which rubber can be made. Each kind of plant gives a different yield of rubber. The plant which gives the hightest yield of rubber is called 'Hevea-Brasiliensis'. It is approximately thirty five metres high. Another high yielding plant is Castilla.
The real development in rubber production took place in the eighteenth century when the samples of rubber giving plants reached America. There is a very interesting story about rubber. When Columbus made his second voyage, he saw the children of the residents of Haiti Island playing with a ball which used to bounce. This ball was taken to Europe. One English scientist named Joseph Gestley observed that pencil writings could be erased by rubbing with this material. Hence it was named rubber.
In the nineteenth century, the use of rubber increased considerably because of its unique properties. It became difficult to fulfill the increasing world demand from the natural rubber. Hence scientists started developing synthetic rubber. The production of artificial rubber was started for the first time in Germany during the First World War. After that synthetic rubber was produced in other countries also. Today about fifty percent of the rubber is produced by synthetic process in the world.
Rubber is very useful for us. Various items of our daily use are made from it. Tyres, tubes, pipes, rain-coats, carpets and water-proof clothes are all made from rubber. Insulation of electric wires is done by coating them with thin layers of rubber. It is soluble in some organic liquids, hence it can be moulded in any form. Today its uses have increased so much that during 1972 the total world production of natural and artificial rubber was 3.1 and 5.3 million tons respectively.

Read More

How the postal system started?

We are all familiar with the importance of the postal system. It is because of this that we are able to receive letters written by our friends and relatives from England or America in six to seven days. Similarly it takes only 2-3 days for the letters to reach us from Bombay, Calcutta or some other places.

All this is the marvel of the postal system. Mail vans, trains and Aeroplanes carry letters sent by us. Millions of people are engaged in this carrying of letters from one place to another.
In the ancient times, man had private arrangements for sending his messages from one place to another. During the 16th century, the governments took over the postal system. There were three main reasons for this. The first reason was the governments' intention to keep an eye on the suspicious messages. The second aim was to earn money through the postal system and the third aim was the welfare of the people. Now the service to the people is prime factor behind the postal system. Up to 1609, special messengers appointed by the governments used to carry letters. In 1680, a businessman of London started his own postal system for the city and its suburbs. In 1840, the entire structure of the postal system in England was modified. This very year postal stamps were issued and postal rates were made uniform for the entire country. Other countries of the world also followed the English system and so the postal system was established throughout the world. Today America has the biggest postal system. It has about 7.5 lac employees and some 100000 million letters are handled by the system every year. In India the postal system was started in 1854. The Air Mail service was started on the 10th February 1911. The postal system of India is considered better than that of America as far as facilities are concerned.

Read More

What is malaria and how it spreads?

All of us are familiar with malaria. More than two million people of the world die of this disease every year. This disease is found in all the countries of the world, but is more common in Central and South America, Far East Asia, Central Africa, countries around the Mediterranean Sea, hot belt areas and places situated on the seashores.
Previously it was believed tht malaria is caused by a poisonous gas produced in dark and damp places. The word 'malaria' is derived from an Italian word meaning 'foul air'. It was Sir Ronald Ross who for the first time in 1902 conclusively proved that malaria is caused by mosquitoes. He was awarded Nobel Prize for this discovery.
Scientific experiments have proved that malaria is caused by a parasite known as Plasmodium. the parasites of malaria are carried by the female anopheles mosquito in its belly which is connected with salivary gland. When the female anopheles mosquito bites some healthy peson, the parsites of malaria enter his blood alongwith the saliva. These parasites attack the red blood corpuscles and destroy them. As a result man gets shivering and high fever. These are the main symptoms of malaria. If not properly treated, red blood corpuscles become scarce and there is obstruction in the veins of the brain. Thus patient can die.
Malaria can be easily treated now. When somebody suffers from malaria, he is given chloroquin tablets. Doctors advise primaquin tablets also for protection from malaria attacks.
Health experts are of the opinion that malaria will be eradicated from this earth one day. They say that in order to stop this disease, it is essential to eliminate anopheles mosquitoes. To fulfil this aim, health organisations from all over the world and governments of many countries have made joint programmes. Under this programme the following advice has been offered to prevent occurrence of malaria.
To prevent malaria, DDT insecticides should be sprayed to destroy the anopheles mosquitoes. Accumulation of water should be prevented so that mosquitoes may not breed there. Mosquito nets should be used while sleeping in the night. At the time of sleeping, the exposed part of the body should be massaged with mustard oil. Kerosene oil should be sprayed over stagnant pools of water. Flit should be sprayed in dark spots of the house. This is the way to stop the transmission of malaria parasites from persons suffering from this disease to healthy persons via mosquitoes.

Read More

How do we get wool from the sheep?

We wear warm clothes during the winter. These clothes are made of wool. We get wool from the sheep. Hair grow on the body of the sheep as they do on our head. This hair of the sheep is called wool. The wool protects the sheep from cold in winter. Do you know how wool is obtained from the sheep?

The hair of a sheep are cut once in a year. When the winter is about to end and the summer is round the corner, the sheep does not require hair. At that time only, the hair of the sheep are clipped by large scissors. The hair so clipped contain thorns, dirt and vegetable oils. To clean it, the hair are made into balls and tied with wool twine. Now, this wool is cleaned. Thereafter, the wool is combed to straighten out the curls. Next it is spun into yarn. The wool yarn is then made into cloth by weaving or knitting.
Nobody knows when man first tamed the sheep. But records reveal that the primitive man had domesticated sheep for both wool and meat. After the passage of centuries, man has now been able to breed many varieties of the sheep. Some of them are valuable for their wool and others for their meat. A species of sheep named 'Merino', found in Spain and Africa is highly productive in wool. Its whole body except legs and nose is covered with hair. Now Merino sheep are found in the United States of America and Australia also which produce large quantities of superior wool. Wool obtained from Merino sheep is very warm.
Today, Australia is the biggest producer of wool in the world. Thirty percent of world's wool is obtained from Australia alone. The United States of America ranks next to Australia. The U.S. produces 300 million pounds of wool every year.

Read More