只要往前数一数这些层次，测量一下每一层里铅的含量，你就可以计算出几百甚至几千年里任何时候全球大气里铅的浓度。这个见解成为冰核研究的基础。许多现代气候学的研究工作都是建立在这个基础上的。

　　What Patterson found was that before 1923 there was almost no lead in the atmosphere, and that since that time its level had climbed steadily and dangerously. He now made it his life's quest to get lead taken out of gasoline. To that end, he became a constant and often vocal critic of the lead industry and its interests.

　　彼得森发现，1923年之前，大气里几乎没有铅；自那以后，铅的浓度不断危险地攀升。现在，把铅撵出汽油成了他一生的追求。为此，他经常批评铅工业及其利益集团，而且往往言辞很激烈。

　　铅的危害

　　It would prove to be a hellish campaign. Ethyl was a powerful global corporation with many friends in high places. (Among its directors have been Supreme Court Justice Lewis Powell and Gilbert Grosvenor of the National Geographic Society.) Patterson suddenly found research funding withdrawn or difficult to acquire. The American Petroleum Institute canceled a research contract with him, as did the United States Public Health Service, a supposedly neutral government institution.

　　这证明是一场残酷的斗争。四乙公司是全球一家势力很大的公司，上头有很多朋友。（它的董事当中有最高法院的法官刘易斯·鲍威尔和美国地理学会的吉尔伯特·格罗夫纳。）彼得森突然发现研究资金要么被收回，要么很难获得。美国石油研究所取消了与他签订的一项合同，美国公共卫生署也是，后者还算是个中立的政府机关呢。

　　As Patterson increasingly became a liability to his institution, the school trustees were repeatedly pressed by lead industry officials to shut him up or let him go. According to Jamie Lincoln Kitman, writing in The Nation in 2000, Ethyl executives allegedly offered to endow a chair at Caltech "if Patterson was sent packing."

　　彼得森成了一个对本单位越来越不利的人。铅工业界官员不断向加州理工学院董事会成员施加压力，要么让他闭嘴，要么让他滚蛋。杰米·林肯·基特曼在2000年的《国家》杂志中写道，据说，四乙公司愿意向加州理工大学无偿提供一名教授讲席的费用，“如果能让彼得森卷铺盖走人的话”。