A. How Archimedes was identified as the author of some ancient texts
B. The recovery of some ancient writings on mathematics
C. Differences among various writing materials used in the Middle Ages
D. Techniques for restoring ancient manuscripts
NARRATOR:Listen to part of a lecture in an art history class.
MALE PROFESSOR:Now, in Europe, in the Middle Ages, before the invention of printing and the printing press, all books, all manuscripts, were handmade.And the material typically used for the pages was parchment, which is animal skin that’s stretched and dried under tension, so it becomes really flat and can be written on.During the 1400s, when printing was being developed, paper became the predominant material for books in Europe, but prior to that, it was parchment.Parchment is durable—much more so than paper.And it could be reused, which came in handy since it was a costly material and in short supply.So it wasn’t uncommon for the scribes, or monks, who produced the manuscripts— uh remember, before printing, books were made mainly in monasteries— well, the scribes often recycled the parchment that’d been used for earlier manuscripts.They simply erased the ink off the parchment and wrote something new in its place.A manuscript page that was written on, erased, and then used again is called a palimpsest.
Palimpsests were created … well, we know about two methods that were used for removing ink from parchment.In the late Middle Ages, it was customary to scrape away the surface of the parchment with an abrasive, which completely wiped out any writing that was there.But earlier in the Middle Ages, the original ink was usually removed by washing the used parchment with milk.That removed the ink, but with the passing of time the original writing might reappear.In fact, it might reappear to the extent that scholars could make out and even decipher the original text.Perhaps the most famous example is the Archimedes palimpsest.
Archimedes lived in Greece around 200 B.C.E. … And as you probably know, he’s considered one of the greatest mathematicians who ever lived, even though many of his writings had been lost, including what many now think to be his most important work, called the Method.But in 1998, a book of prayers from the Middle Ages sold at an art auction for a lot of money, more money than anyone would pay for a damaged book from the twelfth century, beautiful or not. Why?It had been discovered that the book was a palimpsest, and beneath the surface writing of the manuscript lay—guess what?— mathematical theorems and diagrams from Archimedes.
Archimedes’ writings were originally done on papyrus scrolls.Then in the tenth century, a scribe made a copy on parchment of some of his texts and diagrams, including as it turns out, the Method.This was extremely fortunate since later on, the original papyrus scrolls disappeared.About 200 years later, in the twelfth century, this parchment manuscript became a palimpsest when a scribe used the parchment to make a prayer book.So the pages, the pieces of parchment themselves had been preserved, but the Archimedes text was erased and written over, and no one knew it existed.It wasn’t until 1906 that a scholar came across the prayer book in a library and realized it was a palimpsest, and that the underlying layer of text could only have come from Archimedes.That was when his work the Method was discovered for the first time.Uh, the palimpsest then went through some more tough times, but eventually it ended up at an art auction, where it was bought and then donated to an art museum in Baltimore for conservation and study.To avoid further damage to the manuscript, the research team at the art museum has had to be extremely selective in the techniques they use to see the original writing.They’ve used ultraviolet light and some other techniques, and if you are interested in that sort of thing, you can learn more about it in an art conservation class.
But, actually, it was a physicist who came up with a method that was a breakthrough.He realized that the iron in the ancient ink would display if exposed to a certain x-ray imaging method.And except for small portions of the text that couldn’t be deciphered, this technique’s been very helpful in seeing Archimedes’ texts and drawings through the medieval overwriting.
教授：在欧洲中世纪时期，在印刷术发明之前，所有的书、手稿都是手工制作的。而书页主要是用羊皮纸来制作的，这是一种将动物的皮拉伸并在拉力之下使之干燥，所以它就变得很易排版面并能在上面写字了。在 15 世纪，印刷术得到发展的时期，纸张变成欧洲主要制作书籍的材料，但是在那之前，是羊皮纸。羊皮纸很耐用，比纸张耐用很多。而且可以重新使用，这就变得很便利，因为羊皮纸是很贵的材料而且供应紧张。因此对于那些写手稿的抄写员或者和尚来讲，使用就很常见。啊，记得在印刷术发明之前，书籍基本都是在修道院制作的吧。抄写员经常重新使用之前抄写手稿时用过的羊皮纸。他们就将羊皮纸上的墨迹擦拭掉，然后再在上面写上新的东西。这种被书写过，再经过擦拭后重新使用的手稿叫做重写本。
阿基米德在大约公元前 200 年前居住与希腊，你们可能知道，他被看做是亘古以来最出色的数学家之一，即便他多数的手稿都已经丢失，包括我们现在认为的他最重要的成就，称之为方法论。但是在 1998 年的一个艺术拍卖会上，一本中世纪的祈祷书被高价拍卖，比任何一本 12 世纪的受损书籍的价格都要高。很神奇吧，为什么呢？原来这本书被发现是一本重写本，在手稿字迹的下面，猜猜是什么？是阿基米德的数学理论和图解。
阿基米德最初的字是写在纸莎草卷轴上面的。然后在 10 世纪，一个抄写员将他的附图的文章都抄写在羊皮纸的上面，这就是方法论。这简直是非常幸运，因为后来，这个纸莎草卷轴丢失了。大约在200 年后的 12 世纪，这个羊皮纸手抄稿变成了一个重写本，因为一个抄写员用这张羊皮纸制作成了祈祷书。那么书页，一张张羊皮纸就被留存下来。但是阿基米德的文本已经被擦除并已经重新写上了字，所以没有人知道它的存在。直到 1906 年，一位学者来到图书馆偶然看到这本祈祷书，并意识到了这是本重写本，而下面藏匿的内容仅有可能是来自阿基米德。这时他的方法论首次被发现。嗯，重写本经历了风风雨雨，最终到了艺术拍卖会上，然后被人买到又被捐赠到了巴尔的摩的艺术博物馆，来进行保护和钻研。为避免手稿遭到更多的破坏，艺术博物馆研究队伍的人员在想看原始字迹时采用的技术需要及其的谨慎。他们使用过紫外线以及一些其它技术，如果你们对这个感兴趣的话，可以学习一下艺术保护课程。
但是实际上， 是一位物理学家想出的方法有了突破。他意识到古墨水中的铁会在一定的 X 光影像处理方法中显露出来。除了一小部分的内容还没有被破解，这项技术对我们通过中世纪的重写本看阿基米德的文章和图解及其大的有帮助。