目 录 上一节 下一节 
钻石 Diamonds are rare, beautiful, and also quite useful. They are the hardest substance found in nature. That means a diamond can cut any other surface. And only another diamond can make a slight cut in a diamond. 钻石既珍贵稀缺，又美丽晶莹，也用途很广。钻石是自然界里最坚硬的物质。这就意味着钻石能划破任何物体的表面。只有另一块钻石才能在一块钻石上留下轻微的划痕。 Diamonds are made from carbon. Carbon is found in all living things, both plant and animal. Much of the carbon in the earth comes from things that once lived. 钻石（金刚石）由纯碳所组成。在一切生物中，包括动物和植物，都含有碳。地球上的绝大部分碳都是来自从前的生物。 Scientists know that the combination of extreme heat and pressure changes carbon into diamonds. Such heat and pressure exist only in the hot, liquid mass of molten rock deep inside the earth. It is thought that millions of years ago this liquid mass pushed upward through cracks in the earth's crust. As the liquid cooled, the carbon charged into diamond crystals. 科学家们都知道，只有在极高的高温和高压这两个条件结合起来的情况下，才能把碳转化成金刚石（钻石）。这种极其高的高温和高压只有在地球内部深处，溶化了的岩石成极热的液体状态下才能存在。据认为在数百万年以前，这种液态的物质冷却以后，纯碳就变成了钻石结晶。 There are only four areas where very many diamonds have been found. 在全世界只有四个地区发现有大量的钻石 
第一个著名产区就是印度，这里在成千上万年前就发现有钻石。在17世纪从欧洲到印度来的旅行者们从印度带回去一些美丽的宝石，于是钻石就成了欧洲各国的国王和王后们最珍爱的宝物了。 In the 1720's, diamonds were discovered in Brazil. This discovery came at a good time, too. India's supply of diamonds was finally running out after 2,500 years of mining the stones. 到了18世纪20年代在巴西发现了钻石，这一发现恰逢其时。因为印度的宝石经过了2500多年的开采，采到最后已经快被采光了。 In the 1800's, two other important areas were found in Russia and South Africa. Today, most diamonds used in industry come from Russia. Most diamonds used as gems come from South Africa. Only 25 percent of all diamonds mined are good enough for cutting into gems. 到了19世纪，在俄国和南非也发现了两个重要的钻研矿区。今天大部分工业用金刚石都产自俄国。作珍宝装饰用的绝大部分钻石都产自南非。在开采出来的钻石总数当中只有25%的钻石，品级够得上可以打磨成珍宝。 Most of the diamonds in India were found in stream beds. People would pick up handfuls of gravel from the bottom of the streams and sort out the diamonds. These diamonds were probably carried from where they were formed to India by great sheets of moving ice that covered parts of the earth 20,000 years ago. 印度的钻石绝大部分是在河床中发现的。众都是从河床底上捧起一大把一大把的砾石，然后从中挑拣出钻石来。这些钻石很可能在两万年前，整个地球各地都被大片大片的冰川所覆盖着的时期，从钻石生盛典的地方顺着冰川流到印度来的。 Most diamonds today are not found in stream beds, however. They are mined from rock formations deep inside the earth called pipes. Scientists believe that these are parts of volcanoes that were formed when molten rock pushed upward through the earth's crust. The hand rock in which diamonds are found is called blue ground, because it is come what blue. The blue ground is blasted into large pieces of rock which are carried to the surface by elevator. Them the rocks are carefully crushed so that the diamonds are not destroyed. Next the crushed material is taken over to washing tables. Here, it flows over boards thickly coated with grease. Since diamonds stick to grease, they are left behind by the rocks and mud which flow down the tables. 可是，今天绝大多数的钻石都不是在河床上找到的；今天的钻石都是从地球内部很深的地方，从被称为岩筒的管状矿脉的矿井中开采出来的。专家们认为这些岩筒都是火山的一部分，是在溶岩从地壳的裂缝中挤压到上面来的时候形成的。里面含有钻石的坚硬的矿石叫蓝脉矿，因为这种矿石呈微蓝色。把这种蓝脉矿炸成一大块一大块的矿石以便用升降机运送到地面上来。然后再把这一大块一大块的矿石小心翼翼地破开，以便不要把里面钻石给毁坏了。接下来再把这些破开了的小块矿石在冲洗台上过一下，在冲洗台上这些小矿石要流经几块上面涂着很厚一层油脂的板，因为钻石会粘在油脂上而留在冲洗台上，而废矿石和泥浆就沿冲洗台被冲下去了。 
刚发现的钻石并不是很漂亮的。这些钻石都是灰色的，看起来像油粘粘的一些砾石（卵石）。可是经验丰富的钻石开采工一眼就能看出是钻石来。可是也有些人带着一块不寻常的卵石到处跑了几个星期，这才搞清楚了原来他们得到了一块钻石。 The Difference between Plants and Animals 动物与植物之间的差别 If you were asked, "What is the difference between a plant and an animal?" what answer do you think you would give? Your first thought might be that a plant has leaves and roots and flowers, which an animal has not. Yet that would not be correct; for there are many plants which have neither roots nor leaves nor flowers, while there are some animals which seem to have all three. 如果要问你"动物与植物之间的差别是什么？"你想你会给一个什么样的答案呢？你可能首先想到的是植物有叶有根有花，而动物却没有。可是这个答案并不正确，因为有很多植物既没根，也没有叶，更不开花，而有些动物却令人觉得根叶花三者俱备。 Look up into the sky, and then down at the earth beneath your feet. It is easy enough, you think, to tell which is earth and which is sky; but if you live in the wide, open country, or near the sea, you will often find when you look far away to the place where sky and earth seem to meet, that this is a matter of some difficulty. You see only the thin blue haze, like smoke, which is the dividing line between the heavens and the earth. But just where the one ends and the other begins, you cannot tell. 抬头看看天空，然后再低头看看你脚下的大地。你心里会想，要辨别哪是天，哪是地，这还不容易。但是如果你住在视野开阔的农村或住在靠近大海的地方，你就会发现，当你往远处眺望看着天和地相接触的地方，那要分清天和地可就有点难了。你只难看到像烟一样的细细的一片蓝色的薄雾，这就是天和地之间的分界线了。可是你却分辨不出地到底在哪结束，天到底在哪先开头。 Just so it is throughout all the world of Nature. You may look at a group of cows standing under the trees or catch a bee at his early drink in a morning-glory bell, and you would laugh if any one should ask you whether you can tell an animal from a plant. 整个自然界到处都有的正是这种分辨不清的现象。如果你看到几棵大树下面正站着一群奶牛或者你看到在一朵牵牛花当中有一只蜜蜂正吸吮花蕊和那上面的晨露。这时若是有人问你，你能否区别开动物和植物？你就会哈哈大笑。 
但是假如让你把你所熟悉的日用的东西先放到一边，让你去研究一下你必须通过放大镜才能看清的一些东西，那你就会发现有很多东西会使你感到迷惑不解，你就会发现一些没有根、叶、花，也没有种子的植物，你就会发现一些没有头、腿、眼、嘴，也没有肚子的一些动物。 Students of Nature are not satisfied with guessing, but they observe, day after day, the changes which take place in an object; and they see many things which most people would fail to see. And thus they have found that the real difference between plants and animals lies in what they do, and not in what they seem to be. 凡是研究大自然的人，都不会满足于主观猜想，而是日复一日地去观察某一研究对象所发生的一此变化。于是他们就看到了大多数人所看不到的很多情况。这样，他们才发现了动物与植物的区别并不在于它们都似乎是什么样子，而是在于它们做什么。 We now know that about one fourth of all the kinds of seaweed are animals. A few years ago all of them were classed as plants. It was long supposed that the main difference between animals and plants was that the former could move about while the latter could not. But this difference will not hold good. 我们现在知道了在各种的海草当中约有四分之一是动物。可是几年彰这些动物还被划分植物类。人们早就认为动物与植物的主要判别就是动物可以四处活动，而植物则根植于地不能活动。但是这种划分办法是行不通的。 How then are we to know whether a living object is a plant or an animal? Plants can live on inorganic matter; they have the power of changing earth and air and water into substances which enter into and become a part of themselves. Animals can live only on what plants have already turned from inorganic to vegetable matter. Animals, although they need some inorganic food, cannot live on it alone. 那么，到底我们该怎样来判定某种生物究竟是动物还是植物呢？植物靠无机物生长，植物都有一种能力，能把土壤、空气和水转变成能进入植物体内的一种物质，并成为植物本身的一部分。动物只能靠植物来生活，成为动物的主要食品的植物，都是植物由无机物转化成的。虽然动物也需要一点无机物的食品，但是，动物不能只以无机物为主食。 All the food that keeps our bodies strong, or makes them grow, was once in the vegetable from. No bird nor fish nor other animal could ever have lived on this earth, if the plants had not com first and fitted it for the dwelling place of a higher order of beings. 一切能使我们的身体健壮成长的食物都曾经一度以植物形态生存过。如果地球上要不是首先出现了植物，并且在这块也适合于更高层次的生物居住下来的地方扎下了根的话，那么在这个地球上就不会有鸟，不会有鱼，也不会有其他种动物了。 
植物实在是神通广大，植物永不停息地在我们的周围创造奇迹。植物的根深深地扎进土壤里，把土壤中的宝贵的养料都吸收了。植物的叶子在空气中大面积展开，吸进了空气中的养分，植物就用这样吸取到的养分，开出了朵朵美丽的鲜花，结出了种种美味的水果和金灿灿的谷物。 Let us study more closely the way in which a plant grows. The root pushes itself down into the earth. If it finds no water, it soon dies. If it finds water, it begins to suck it up and change it into sap. Besides the water, it takes up such parts of the soil as are dissolved in the water. 让我们来更加细微的观察一下植物的生长方法。植物的根深深地扎进了土壤，如果找不到水，很快地就死了，如果根找到了水，它就把水吸上来使之变成植物的汁液，除了水之外，根还吸收了土壤中可溶于水的养分。 Here, then, you see in what ways the food of the plant is different from that of animals. 说到这里你就会明白，植物吸收养料的办法与动物吸收养料的办法是不同的。
| 
