We do not know when man first began to use salt, but we do know that it has been used in many different ways throughout history. Historical evidence shows, for example, that people who lived over 3,000 years ago ate salted fish. Thousands of years ago in Egypt, salt was used to preserve (保存) the dead.

    Stealing salt was considered a major crime (罪行) during some periods of history. In the eighteenth century, for example, if a person was caught stealing salt, he could be put in prison and his ears could be cut off.

    In the Roman Empire, one of the most important roads was the one that carried salt from the salt mines to Rome. Guards were stationed(安置) along the route to protect against salt thieves, and they received their pay in salt, thus bringing the English word, salary. Any guard who fell asleep while on duty was thought to be “not worth his salt”, and as a result he would get a little less salt on his next payday. The expression, “not worth his salt”, is still used today in English.

    In the modern world salt has many uses beyond the dining table. It is used in making glass and airplane parts, in the growing of crops, and in the killing of weeds (杂草). It is also used to make water soft, to melt (融化) ice on roads and highways, to make soap, and to fix colors in cloth.

    Salt can be got in various ways besides being taken from mines underground. Salt water from the ocean, salt water lakes or small seas can be used to make salt. Yet, no matter where it comes from, salt will continue to play an important role in the lives of people everywhere.

     Scientists have found living organisms trapped in crystals(晶体) that could be 50,000 years old.

     The organisms were found in a hot, but beautiful cave system in Naica, Mexico. These ancient life forms can be seen only with a microscope. Penelope Boston, who leads the Astrobiology Institute at NASA, the space agency of the United States, says the ancient microbes(微生物) were able to live by eating minerals such as iron.

     She spoke about the discovery recently at a meeting of the American Association for the Advancement of Science. If the findings are confirmed, they will show how microbes can survive in extreme conditions. Forty different kinds of microbes and some viruses were found in the underground area. The genetic structures of these organisms are 10 percent different from those of their nearest relatives.

     The caves in Naica are 800 kilometers deep. They were once used for mining lead. Before the miners began working in the caves, the area was separated from the surface and the outside world. Some of the caves are as big as the large religious centers built during Europe's Middle Ages. There are crystals covering the walls. The caves are so hot that scientists must wear special clothing to keep cool. The clothing keeps the crystals safe from human germs（病菌）or other damage. Boston said the researchers could only work for about 20 minutes at a time before they had to go to a room that was 38 degrees Celsius to cool down.

     NASA officials would not let Boston share her findings with scientific experts before last week's announcement. So scientists could not say much about the findings. But Norine Noonan, a biologist with the University of South Florida, said she believed them. "Why are we surprised?" Noonan asked. "As a biologist, I would say life on Earth is extremely tough and extremely colorful."

     Boston is also studying microbes commonly found inside caves in other countries, such as Ukraine and the United States. These microbes appear to be impossible to kill. Boston said they show how difficult life on Earth can be.

    A team of engineers at Harvard University has been inspired by Nature to create the first robotic fly. The mechanical fly has become a platform for a series of new high-tech systems. Designed to do what a fly does naturally, the tiny machine is the size of a fat housefly. Its mini wings allow it to stay in the air and perform controlled flight tasks.

    “It's extremely important for us to think about this as a whole system and not just the sum of a bunch of individual components,” said Robert Wood, the Harvard engineering professor who has been working on the robotic fly project for over a decade. A few years ago, his team got the go-ahead to start piecing the components together. “The added difficulty with a project like this is that actually none of those components are off the shelf and so we have to develop them all on our own,” he said.

    They engineered a series of systems to start and drive the robotic fly. “The seemingly simple system which just moves the wings has a number of interdependencies on the individual components, each of which individually has to perform well, and then has to be matched well to everything it's connected to,” said Wood. The flight device was built into a set of power, computation, sensing and control systems. Wood says the success of the project proves that the flying robot with these tiny components can be built and manufactured.

    Wood says the design offers a new way to study flight mechanics and control at insect-scale. Yet, the power, sensing and computation technologies on board could have much broader applications. “You can start thinking about using them to answer open scientific questions, you know, to study biology in ways that would be difficult with the animals, but using these robots instead,” he said. “So there are a lot of technologies and open interesting scientific questions that are really what drives us on a day to day basis.”

    A sunflower is a sunflower. A mobile phone is a mobile phone. But can you combine the two to do something for your local environment? As early as next year it may well be possible. When you have finished with your mobile phone you will be able to bury it in a garden or a plant pot and wait for it to flower.

    A biodegradable (生物所能分解的) mobile phone was, this month, introduced by scientists. It is hoped that the new type of phone will encourage consumers to recycle.

    Scientists have come up with a new material over the last five years. It looks like any other plastic and can be hard or soft, and is able to change shape. Over time it can also break down into the soil without giving out any poisonous chemicals. British researchers used the new material to develop a phone cover that contains a sunflower seed. When this new type of cover turns into waste, it forms fertilizers. These feed the seed and help the flower grow.

    Engineers have designed a small transparent (透明的) window to hold the seed. They have made sure it only grows when the phone is throw n away. “We've only put sunflower seeds into the covers so far. But we are working with plant experts to find out which flowers would perform best. Maybe we could put roses in next time.” said one scientist.

    As phone technology is developing so quickly, people are constantly throwing their mobiles away. This means manufacturers are under pressure to find ways of recycling them. Some 650 million mobile phones have been sold this year. Most of them will be throw n away within two years, adding plastic, heavy metal and chemical waste to the environment. A biodegradable cover can offer some relief for nature, according to the scientists.

    “The seed comes out and the flower grows in the pot so you don't have to concern yourself with the phone when you have finished using it,” said Kerry Kirwan. She leads the research team, which is based at the University of Warwick in Britain.

    Charlie is a teacher and his wife, Maria is an artist. The night before last, just before the longest day of the year, Charlie was sitting in a deckchair enjoying the warm summer air when Maria touched his shoulder and he could tell immediately she was a little worried about something. He asked her what the matter was and she replied that there was a strange thing on the jacket that was hanging in the bedroom. They had both lived in the West Indies (西印度群岛) and had seen a lot of strange creatures in their house before. But now they were living in England and so Charlie just laughed and said he would have a look at the “thing”.

    He walked to the bedroom. He saw a jacket hanging in the bedroom and went up to it to have a closer look at the “thing”. The moment he touched it, the thing sprang into life. Now Charlie experiences fear like the rest of us but when this creature opened its wings, he jumped out of his skin and ran screaming from the room like a small child doing about 100 miles an hour.

    For a moment the next-door neighbours thought that Charlie was murdering his wife because of the noise they could hear. In fact, it was a bat that frightened Charlie.

Eventually Charlie managed to trap the bat in a box and took it to the garden to let the bat fly. Maria, who had been playing the guitar while Charlie was upstairs, asked Charlie if he had found out what the thing was. “Oh, nothing to worry about”, he said casually hoping that the terror could not be seen in his eyes, “it was just a bat.”

The World's Largest Libraries

    British Library (United Kingdom, London)

    The British Library was created by Act of Parliament in 1972; previously, the library had been part of the British Museum, where the famous circular reading room had accommodated researchers including Karl Marx, who worked on 'Das Kapital' there, as well as Oscar Wide and Mahatma Gandhi. The British Library is now housed in a new building in St. Pancras, London, where its treasures include two Gutenberg bibles, the Lindisfarne Gospels and one of Leonardo da Vmci's notebooks.

    Library of Congress (United States, Washington, D. C.)

    Founded in 1800 with the private collection of Thomas Jefferson, the Library of Congress is in effect the USA's National Library. It receives two copies of everything published in the United States. The Library of Congress wag burned by the British Army in 1812, and severely damaged by fire again in 1851. The collection includes many rare books, drawings and two Stradivarius violins.

    New York Public Library

    The New York Public Library developed gradually in the nineteenth century from the merger and acquisition (收购兼并) of a number of public and private collections; it has many branches in different districts of New York City. It remains a structure which combines public and private finance and governance. Treasures held at the library include a Gutenberg Bible.

    Russian State Library (Moscow)

    Founded in 1862 as the Moscow public library and museum, this collection became the State Library in 1925. In consequence it receives copies of all Russian publications, and also holds large collections of maps, journals, music scores and recordings. Its possessions include the Archangel Gospel, a codex in the Slavonic language dating from 1092.