英國學(xué)生科學(xué)讀本 Lesson 39 柔韌的軟金屬-鉛(2)

When the sheets are very thin, they are called lead-foil. A great deal of lead-foil is used in China, to line the chests in which tea is sent to Europe.

特別薄的薄片兒就叫做“鉛箔”, 中國就是用大量的鉛箔來墊在茶葉箱里, 做成“鉛襯里”, 把茶葉運(yùn)到歐洲的。

Lead is much used for making water-pipes, and for lining water-systems. If the water which runs through the pipes is very soft and pure, it may dissolve a little of the lead, and make the water poisonous.

制造水管、蓄水池的襯里, 都要用很多鉛。如果流過管子的水很軟, 很純, 就會(huì)把少量鉛溶解掉, 讓水帶有毒性。

But the water which comes to our houses is almost always hard water. Now hard water soon forms a white crust on the inside of the pipe, and this crust keeps the water from touching the lead.

但是流到我們屋子里的水, 差不多總是硬水。硬水在管子內(nèi)壁很快就會(huì)形成一層白色的水垢, 水垢就不會(huì)讓水接觸到鉛了。

Lead is very heavy; it is much heavier than iron or copper. It is an easy metal to melt. Put some bits of sheet-lead in an iron spoon, and place the spoon on a clear fire. Soon the lead melts. Do you see the crust of dross or lead-rust on the surface?

鉛非常沉重, 比鐵或銅要重得多。鉛很容易熔化。把一些碎鉛皮放在鐵勺子里, 把鐵勺子放在明火旁邊, 鉛很快就會(huì)熔化。鉛皮表面那一層渣滓的硬膜——也就是鉛銹, 你看到了嗎?

Skim this off with a bit of dry wood, and pour the melted metal slowly into a pail of cold water from a heightof two or three feet. The water cools the lead at once, and the metal becomes solid again. Some of the little pieces of solid lead which you will find in the pail will very likely have most curious shapes.

用干木頭片兒把鉛銹刮下來, 把熔化的鉛, 從兩三英尺的高度, 慢慢倒進(jìn)一桶水中。水馬上就把鉛冷卻了, 這種金屬又會(huì)變回固態(tài)。在桶里找到的一些固態(tài)鉛的小塊, 很可能是奇形怪狀的。

 

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