VOA慢速英语2010年-Development Report - Bringing Color to

This is the VOA Special English Development Report.

Dye can bring a little color to life. Most clothing is colored with dyes. Modern, manufactured dyes can be costly¹. Natural dyes from plant and animal products have been used since ancient times. So this week, we describe a natural way to dye wool.

The advice comes from information written by Jenny Dean of the Intermediate Technology Development Group in Britain. This anti-poverty group is now called Practical Action.

There are several methods to put dye onto material. The vat² method, for example, can be used to dye wool with onionskins. For this example, use one hundred grams of natural wool. The wool must be clean. Leave it overnight in water and liquid soap. Then wash it with clean water that is a little warm. Gently squeeze out the extra water.

A solution called a mordant³ is used in the dying process. A mordant helps fix the dye to the material. Traditionally, mordants⁴ were found in nature. Wood ash is one example. But chemical mordants such as alum are popular today. Alum is sold in many stores. It is often mixed with cream of tartar, a fine powder commonly used in cooking.

Mix eight grams of alum with seven grams of cream of tartar in a small amount of hot water. Add the solution to a metal pan of cool water. Next, add the wool and place the mixture over heat. Slowly bring the liquid to eighty-two degrees Celsius⁵. Heat the mixture for forty-five minutes. After it cools, remove the wool and wash it.

To prepare the dye solution, cover thirty grams of onionskins with water. Use only the dry, brown outer skins. Boil the liquid until the onionskins lose their color, about forty-five minutes,. Remove the skins after the dye cools.

Now it is time to dye the wool. Place the wool into the dye and heat the mixture. Bring it to a boil, then immediately reduce the heat to eighty-two degrees. Now heat the dye for about forty-five minutes or until the wool is the desired color. Keep in mind that wet wool looks darker than it is.

Once the dye cools, remove the wool and wash it. Now the wool is orange or yellow. Or at least it should be.

Internet users can get the full details at practicalaction.org. Again, the address is practicalaction dot org. And enter the word "dye," d-y-e, in the search box. We will post a link to the site at voaspecialenglish.com.

And that's the VOA Special English Development Report, written by Jill Moss⁶. I'm Steve Ember.

1 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

2 vat   

n.(=value added tax)增值税，大桶

参考例句：

• The office is asking for the vat papers.办事处要有关增值税的文件。
• His father emptied sacks of stale rye bread into the vat.他父亲把一袋袋发霉的黑面包倒进大桶里。

3 mordant   

adj.讽刺的；尖酸的

参考例句：

• Actors feared the critic's mordant pen.演员都惧怕这位批评家辛辣尖刻的笔调。
• His mordant wit appealed to students.他那尖刻的妙语受到学生们的欢迎。

4 mordants   

vt.媒染，用媒染剂处理（mordant的第三人称单数形式）

参考例句：

• But chemical mordents mordants such as allon alum are popular today. 但是化学腐蚀剂例如明矾现在很流行。 来自互联网
• But chemical moments mordants such as alen alum are popular today. 但是像明矾这样的化学染剂现今很流向。 来自互联网

5 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

6 moss   

n.苔，藓，地衣

参考例句：

• Moss grows on a rock.苔藓生在石头上。
• He was found asleep on a pillow of leaves and moss.有人看见他枕着树叶和苔藓睡着了。