【正文】 r. When he used an icebox of his own design to transport his butter to market, he found that customers would pass up the rapidly melting stuff in the tubs of his petitors to pay a premium price for his butter, still fresh and hard in neat, onepound bricks. One advantage of his icebox, Moore explained, was that farmers would no longer have to travel to market at night in order to keep their produce cool.31 British ColumbiaBritish Columbia is the third largest Canadian provinces, both in area and population. It is nearly times as large as Texas, and extends 800 miles(1,280km) north from the United States border. It includes Canada’s entire west coast and the islands just off the coast. Most of British Columbia is mountainous, with long rugged ranges running north and south. Even the coastal islands are the remains of a mountain range that existed thousands of years ago. During the last Ice Age, this range was scoured by glaciers until most of it was beneath the sea. Its peaks now show as islands scattered along the coast.The southwestern coastal region has a humid mild marine climate. Sea winds that blow inland from the west are warmed by a current of warm water that flows through the Pacific Ocean. As a result, winter temperatures average above freezing and summers are mild. These warm western winds also carry moisture from the ocean.Inland from the coast, the winds from the Pacific meet the mountain barriers of the coastal ranges and the Rocky Mountains. As they rise to cross the mountains, the winds are cooled, and their moisture begins to fall as rain. On some of the western slopes almost 200 inches (500cm) of rain fall each year.More than half of British Columbia is heavily forested. On mountain slopes that receive plentiful rainfall, huge Douglas firs rise in towering columns. These forest giants often grow to be as much as 300 feet(90m) tall, with diameters up to 10 feet(3m). More lumber is produced from these trees than from any other kind of tree in North America. Hemlock, red cedar, and balsam fir are among the other trees found in British Columbia.32 Botany Botany, the study of plants, occupies a peculiar position in the history of human knowledge. For many thousands of years it was the one field of awareness about which humans had anything more than the vaguest of insights. It is impossible to know today just what our Stone Age ancestors knew about plants, but form what we can observe of preindustrial societies that still exist a detailed learning of plants and their properties must be extremely ancient. This is logical. Plants are the basis of the food pyramid for all living things even for other plants. They have always been enormously important to the welfare of people not only for food, but also for clothing, weapons, tools, dyes, medicines, shelter, and a great many other purposes. Tribes living today in the jungles of the Amazon recognize literally hundreds of plants and know many properties of each. To them, botany, as such, has no name and is probably not even recognized as a special branch of “ knowledge” at all.Unfortunately, the more industrialized we bee the farther away we move from direct contact with plants, and the less distinct our knowledge of botany grows. Yet everyone es unconsciously on an amazing amount of botanical knowledge, and few people will fail to recognize a rose, an apple, or an orchid. When our Neolithic ancestors, living in the Middle East about 10,000 years ago, discovered that certain grasses could be harvested and their seeds planted for richer yields the next season the first great step in a new association of plants and humans was taken. Grains were discovered and from them flowed the marvel of agriculture: cultivated crops. From then on, humans would increasingly take their living from the controlled production of a few plants, rather than getting a little here and a little there from many varieties that grew wild and the accumulated knowledge of tens of thousands of years of experience and intimacy with plants in the wild would begin to fade away.33 Plankton浮游生物. / 39。 sэ`linэti/ n [U] the high salinity of sea water 海水的高含鹽量.224。 咸的: * a saline lake 鹽湖 * saline springs 鹽泉 * saline solution, eg as used for gargling, storing contact lenses, etc 鹽溶液（如用于漱喉、存放隱形眼鏡等）.2. n [U] (medical 醫(yī)) solution of salt and water 鹽水.40 Cohesiontension TheoryAtmospheric pressure can support a column of water up to 10 meters high. But plants can move water much higher。 黃寶石.39 The Salinity of Ocean WatersIf the salinity of ocean waters is analyzed, it is found to vary only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation conversion of liquid water to water vapor. In this manner the salinity is increased, since the salts stay behind. If this is carried to the extreme, of course, white crystals of salt would be left behind.The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas of high rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of fresh water by precipitation or runoff.Normally, in tropical regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.A third process by which salinity may be altered is associated with the formation and melting of sea ice. When sea water is frozen, the dissolved materials are left behind.