1563年，随着佛罗伦萨统治者的一声令下，列奥纳多·达·芬奇的惊世杰作《安吉亚里之战》从此消失无踪。然而，艺术侦探毛里齐奥·塞拉奇尼却深信《安吉亚里之战》被秘密保存了下来。在450年后的今天，他要如何利用高科技手段让这幅尘封已久的壁画重见天日，让后世之人有幸一睹其绝世真容呢？
Four hundred fifty years ago, one of the world's greatest masterpieces vanished. Leonardo da Vinci had painted a huge mural2), The Battle of Anghiari, in 1505 to commemorate3) a military victory of the government of Florence, Italy. Even though Leonardo never completed the mural, experts who saw the painting considered it his most impressive work—far more important than his Mona Lisa. The scene of two armies meeting, with clashing horses and soldiers, stretched4) across a wall in the Hall of the 500, where Florence's political leaders used to gather.
450年前，世界上最伟大的珍品画作之一消失得无影无踪。1505年，列奥纳多·达·芬奇绘制了巨幅壁画《安吉亚里之战》，以纪念当时意大利佛罗伦萨政府所取得的军事胜利。虽然壁画并未完成，但目睹过这幅作品的行内专家却认为这是达·芬奇最令人惊叹的作品——远比他的《蒙娜丽莎》更具重要意义。壁画描绘了两军兵马激烈交战的场面，纵横铺展在五百人大厅的一侧墙壁上。过去，佛罗伦萨的政要们常常在此厅相聚会谈。
In 1563, a new ruler—who wasn't crazy about a mural that honored the previous government—commissioned5) architect Giorgio Vasari6) to give the hall a makeover. When Vasari covered the walls with six new scenes, The Battle of Anghiari disappeared, seemingly painted over or destroyed. But Maurizio Seracini, an engineer and art detective at the University of California, San Diego, believes Vasari secretly saved Leonardo's mural. New technology is uncovering clues to the fate of the missing masterpiece.
然而，新继任的统治者却对这幅颂赞前届政府的壁画兴趣寥寥。1563年，他委任建筑师乔治·瓦萨里对大厅进行重新修整。瓦萨里在原有墙壁上覆盖了六幅新画作，《安吉亚里之战》从此不复存在，似乎是被重新粉饰了，抑或早已毁灭殆尽。但美国加州大学圣地亚哥分校的工程师兼艺术侦探毛里齐奥·塞拉奇尼却认为，瓦萨里秘密地保留了达·芬奇的壁画。于是，他借助新的科技手段，试图揭开这幅失踪名画的神秘面纱。
Hidden Clues 暗藏玄机
Vasari had a history of secretly protecting paintings. When remodeling7) a church in Florence, he made its artwork seemingly disappear. Three hundred years later, however, workers accidentally found it. Vasari had built a wall in front of the painting to preserve it. Seracini thought, "Maybe he did the same this time to save such an important masterpiece. "
瓦萨里过去曾在暗地里保护过不少画作。他曾对佛罗伦萨的一间教堂进行改建，结果教堂内的艺术画作在他的处理下似乎全部了无踪迹。然而，三百年后，教堂工作人员却又偶然发现了原画。原来，为了保存画作，瓦萨里在画前又修筑了一堵墙。据此，塞拉奇尼想道：“也许，瓦萨里在翻修的时候故伎重施，也将这幅弥足珍贵的画作保留了下来。”
Seracini set up scaffolding8) to examine the east wall in the Hall of the 500 to search for hints of the missing Leonardo mural. It was then that he spotted9) the Italian words "CERCA TROVA", meaning "seek, and you shall find", painted on a green flag. These were the only words on any of Vasari's murals in the vast hall, and they weren't visible from the floor. "And so I wondered, 'why on Earth would somebody write words that nobody could read?'" Seracini says. He couldn't shake the feeling that the phrase was a clue from Vasari.
为了找到失踪壁画中的蛛丝马迹，塞拉奇尼在五百人大厅搭起脚手架，对其东侧墙壁进行了仔细排查。就在那时，他在壁画中的一面绿旗上发现了一行意大利文字“CERCA TROVA”，意为“寻找下去，会有发现”。这是瓦萨里在这间广阔的大厅所创作的壁画中留下的唯一字迹。从地面看去，根本无法察觉这些文字。“对此，我感到很疑惑，‘究竟为什么有人会写下这些人们无法看到的文字呢？’” 塞拉奇尼说。他有一种挥之不去的预感：这是瓦萨里留下的一种暗示。
No one knew exactly where in the hall Leonardo had painted his mural. So Seracini used a thermal imaging10) camera that detects heat energy to create infrared11) images of the hall. Since different materials—such as bricks, stones, and plaster—give off different amounts of infrared radiation, the images revealed the changes Vasari had made to the hall's structure. Seracini explains, "We managed to discover the original windows, the original doors, and the height of the ceiling, and therefore exactly the architectural layout as Leonardo saw it when he started to paint." This evidence, along with details from eyewitness accounts, led experts to conclude that The Battle of Anghiari had covered part of the east wall—right below where the words "CERCA TROVA" now appear.
没有人知道达·芬奇那幅壁画在大厅的确切位置。因此，塞拉奇尼只得求助于热成像相机来获取大厅的红外图像。这种相机能探测到物体的热能。由于不同的物体——比如砖块、石料、石膏等——会释放出不同数量的红外辐射，因此，根据这些红外图像，他们能够得知瓦萨里对大厅结构所做的种种调整。塞拉奇尼解释说：“我们已经设法弄清了原来门窗的位置以及天花板的高度，所以，现在我们已经准确掌握了列奥纳多作画时所见大厅的建筑布局。”专家们根据这一发现以及当时目击者描述的细节得出结论，认为《安吉亚里之战》绘制在东侧的部分墙壁上——就在“寻找下去，会有发现”那行字现在所处位置的正下方(本文题图即为瓦萨里在东侧墙壁所绘壁画)。
Seeing Through Walls 看穿迷墙
Using portable radar equipment, Seracini next sent microwaves into the wall. Like infrared radiation, microwaves are electromagnetic radiation12)—but with longer wavelengths. "The [microwaves] bounce back13), just like an echo," explains Raymond DuVarney, a physicist at Emory University in Georgia. "The longer it takes to get back, the farther away the surface is." The radar revealed an air gap behind the east wall, with a second wall behind the gap. None of the other walls is concealed14) a similar gap.
接下来，塞拉奇尼借助便携式雷达仪对墙壁进行了微波探测。和红外辐射一样，微波也属于电磁辐射，但它的波长更长。“微波能像回声一样反弹回来，”美国佐治亚州埃默里大学物理学家雷蒙德·杜·瓦尼解释说，“回来所需的时间越长，物体表面离我们的距离就越远。”雷达探测的结果显示，大厅的东墙后面有一道空隙，空隙之后还有另外一堵墙。而大厅内其他墙壁后方并没有类似的空隙。
Seracini hypothesizes15) that Vasari had left the gap in front of Leonardo's mural to preserve it. He wanted to test his theory, but without damaging Vasari's mural, which is also a masterpiece, when it seemed that the search had reached a dead end, Seracini spoke at a physics conference. DuVarney was there and heard him challenge the audience by asking, "Can you come up with some way that I can see behind this wall?" No one could. But the next morning, DuVarney woke up with an idea.
塞拉奇尼猜测，为了保护原画，瓦萨里可能在达·芬奇的壁画前留下了这处空隙。塞拉奇尼在一个物理学会议上发言时说，他想验证自己的推理，但又不能毁坏瓦萨里的壁画，因为那同样是杰作。研究似乎陷入了死胡同。当时，与会的杜·瓦尼听到他向听众提出了一道难题：“有人能想出让我一睹墙后秘密的办法吗？”在场人员无人应答。但是，第二天杜·瓦尼一觉醒来，就想到了一个主意。
Taking Aim 有的放矢
The key to DuVarney's plan: The pigments16) in the missing mural's paints got their colors from different chemical elements. For instance, a list of Leonardo's materials reveals that he used white paint containing lead and bright red paint containing mercury17). If researchers could tell which elements were on the hidden wall, they would know which colors were painted there and could make out the design. DuVarney wanted to "activate" these elements so they would give themselves away18). "What you're trying to do is to get the mural behind the wall to shine back at you," he says.
杜·瓦尼方案的关键在于：那幅失踪壁画的颜色取源于不同的化学元素。例如，根据达·芬奇的绘画用料表可知，他所使用的白色颜料里含有铅，亮红色颜料里含有汞。如果研究人员能够识别暗墙上含有的化学元素，那么就能知道墙壁上涂了哪些颜色，从而得知暗墙的设计图案。杜·瓦尼试图“激活”这些元素，使其自行显示出来。“你要做的就是促使隐藏在墙后的壁画向你发光。”他说。
To accomplish this, DuVarney proposed shooting a beam of neutrons19)—uncharged20) particles21)—through the outer wall. If Leonardo's mural really is on the inner wall, then the nuclei22) of the paint's atoms will absorb these neutrons. This makes the atoms unstable, so they break down and give off gamma rays23)—a type of high energy electromagnetic radiation. Each chemical element emits24) gamma rays of a different energy, so this would reveal the identities of the elements in the paint. "And that would give you the color and the structure," DuVarney says. "And you could see if it matched anything that might resemble25) The Battle of Anghiari."
为此，杜·瓦尼提议用中子束——不带电荷的粒子——来穿透外墙。如果暗墙上确有达·芬奇的壁画，那么颜料原子中的原子核就会吸收这些中子，从而使原子结构失去稳定性，继而发生分解，释放出伽马射线——一种高能电磁辐射。不同的化学元素会释放出不同能量级的伽马射线，这些射线昭示了壁画上的元素种类。“这样你就能获知壁画的颜色和构图，” 杜·瓦尼说，“然后比对一下，看看所得图像是否符合《安吉亚里之战》的概貌。”
Seracini has already tested the new technology on mock26) walls painted with the types of pigments Leonardo used. The final step is to build a portable machine to take to Florence to scan the real thing. Seracini hopes to solve the mystery by the end of this year, but he doesn't plan to stop there. He says, "Once we have built this portable unit, we use this technology to search for hundreds of other murals hidden everywhere on the planet."
塞拉奇尼已经在模拟墙上试验了这一新技术。他在这些模拟墙上涂上了达·芬奇使用的那些颜料。现在只剩最后一步：制造一个便携式中子发射仪，拿到佛罗伦萨对墙壁进行实体扫描。塞拉奇尼希望在今年年底前解开这一谜团，但他并不打算就此停下脚步。他说：“一旦我们研制出了这种便携式的仪器，我们将用该技术去搜寻其他所有遍布世界各地的、数以百计的隐藏壁画。”
1. sleuth [slu:W] n. <口> 侦探；侦查者
2. mural [5mjuErEl] n. 壁画，壁饰
3. commemorate [kE5memEreIt] vt. 纪念
4. stretch [stretF] vi. 伸展，延伸
5. commission [kE5mIFEn] vt. 委托制作(或做、完成) (某事物)
6. Giorgio Vasari: 乔治·瓦萨里(1511～1574)，意大利画家、建筑师和美术史家，其画风属风格主义，代表作为《百日壁画》，尤以著作《意大利杰出建筑师、画家和雕塑家传》而闻名。
7. remodel [7ri:5mCdEl] vt. (按另一模型或样式)改造，改制；改建
8. scaffolding [5skAfEldIN] n. 【建】脚手架；脚手架组
9. spot [spCt] vt. <口> 发现；发觉；
10. thermal imaging: 热成像
11. infrared [7InfrE5red] adj. 红外线的；红外区的
12. electromagnetic radiation: 电磁辐射
13. bounce back: 弹回；跳回
14. conceal [kEn5si:l] vt. 隐藏，掩盖
15. hypothesize [haI5pCWIsaIz] vt. 假设，假定
16. pigment [5pI^mEnt] n. 颜料，涂料
17. mercury [5m\:kjurI] n. 【化】汞，水银
18. give away: 泄露；暴露
19. neutron [5nju:trCn] n. 【物】中子
20. uncharged [7Qn5tFB:dVd] adj. 无电荷的，不带电的
21. particle [5pB:tIkl] n. 【物】粒子，质点
22. nuclei [5nju:klIaI] n. nucleus的复数形式；nucleus [5nju:klIEs] n. 【核】核
23. gamma ray: 【核】γ射线(高能光子或波长极短的电磁辐射)
24. emit [I5mIt] vt. 发射(电子)
25. resemble [rI5zembl]vt. 像，与……类似；类似于
26. mock [mCk] adj. 假的，模拟的