2.We call the stuff black-lead，because it makes marks like lead；but there is really no lead in it at all.Black-lead is not a metal.It is made of carbon，which is also found in coal and in many other things.It is the carbon in coal which makes it burn so well.
3.If we make black-lead very hot，it will burn.But it will burn very slowly-so slowly that it would be of no use for making a fire.
4.Black-lead is found in some kinds of rocks in big lumps.These lumps are ground into very fine powder，and then the powder is pressed into hard blocks.
5.These blocks are next cut up into thin strips.Each strip of black-lead is made of just the right size to fit into the hollow that has been cut for it in the wood of the pencil.
6.Your mother will tell you that black-lead is very useful to her in the house.She rubs it on stoves and grates，and many other things that are made of iron，to cover the iron and keep it from rusting.
7.The damp air makes the iron rust；but when we cover it with black-lead，the air cannot reach it，and it keeps bright.
8.Have you ever seen a diamond？It is a very bright，hard kind of stone，and very dear.Diamonds are sometimes set in gold rings，and they are very pretty.Yet the diamond is made of pure carbon，just as black-lead is.
9.Is it not strange that the dull black-lead，which costs so little，and the sparkling diamond，which costs so much，are both made of the same stuff that burns in the grate to keep us warm？
SUMMARY
Black-lead is a kind of matter called carbon.It is found in some kinds of rocks in big lumps.It is put on stoves and grates and other things to keep them from rusting.It is made of the same kind of stuff as the sparkling diamond and the common black coal.
【中文阅读】
1．小朋友，你铅笔里的铅芯是什么做的？拿一块儿叫“铅”的金属看看，铅是黑色的，特别重，跟铅芯一点儿也不一样。但是铅也会在纸上留下印子，跟铅笔一样。①2．我们把铅芯里的东西叫石墨（black-lead），就是“黑铅”的意思。这是因为，它在纸上也能像铅一样留下印子；但其实，铅芯里一点儿铅都没有。石墨是碳做的，煤里就有碳，好多别的东西里也有碳。煤里正是有了碳，才会这么容易燃烧的。②3．如果把石墨弄得特别热，石墨就会燃烧起来，但是燃烧得特别慢，不能用它生火。
4．有一些石头里面会有大块的石墨。人们把这些大块石墨，先磨成细粉，又压成硬块儿。
5．这些硬块儿，最后又切成了细条。同时，在铅笔的木头上，也切出来了凹槽。每一根石墨的细条，大小都正好放进凹槽里面。③6．小朋友，你的妈妈会告诉你，石墨在你家里也非常有用！妈妈把石墨涂在炉子、炉栅上面，涂在很多铁器上面，把铁盖起来，这样它们就不会生锈了。④7．潮湿的空气会让铁生锈，但是只要用石墨盖住，铁就接触不到空气，会一直亮闪闪的。
8．小朋友，你见过钻石吗？钻石，也叫金刚石，是一种非常光亮，非常坚硬的石头，价钱还特别贵。有些钻石嵌在金戒指上，漂亮极了。可是，钻石却是纯碳做的，就跟石墨一样！⑤9．黑黑的石墨那么便宜，亮晶晶的钻石那么贵，这两种东西，却跟那烧在炉子里让我们取暖的煤，都是一样的东西做的，好奇怪呀！⑥译注①在中国，1900多年以前的东汉初期，人们就开始使用铅，作为方便的书写工具了；欧洲的古罗马贵族也用铅条写字。但是这种真正的“铅笔”缺点太多：有毒，容易折断，字迹模糊，所以几百年前就让位给石墨了。人们刚发现石墨的时候，误以为是铅的一种，于是很多语言，包括汉语里的“铅笔”都带有“铅”这个字，谁也不愿意改了。另外，直到20世纪中期，铅笔外面的涂层经常含有铅，所以那时候的人在咬铅笔的时候，还真的容易造成铅中毒。
②石墨的现代名字叫graphite。石墨矿最早发现在英国的昆布兰郡（Cumbria），时间大概在1500-1565年之间。人们最早用天然石墨在绵羊身上画记号，后来石墨又用来在加农炮的模具上划线，有一阵子曾经成为重要的战略物资。英王乔治二世（King George II）甚至下过一道命令，禁止从昆布兰郡偷运石墨，违者处以绞刑。
③现代工艺中，石墨需要跟粘土按比例混合，用“压芯机”挤压出细条（也就是铅芯），干燥，用高温焙（bèi）烧，最后在油或者石蜡里浸一遍，才能做成。
④现在家里的大部分炉子都涂了防锈漆，不需要居民自己往上涂防锈材料了。不过，一些工厂里的机器，还用石墨来防锈。
⑤20世纪50年代以后，出现了用石墨等碳原料加工的人造钻石，广泛用在工业和珠宝加工业上。
⑥石墨和钻石都是纯碳，但里面碳原子排列的方式不一样，所以才会出现这么不同的形态。煤不是纯碳，而是碳、氢、氧、氮、硫等元素组成的复杂的有机物。
THE COW