Two hundred years ago, Captain James Cook circled Antarctica, saw that it was ice-covered, and lamented that man would "de- rive no benefit from it." But European and, later, American ex- plorers still pushed south, driven what one of them called the "Intellectual Passion"-the pursuit of knowledge for its own sake. By the end of the 19th century, Antarctica was the last un- charted territory on Earth. Today, the geography of the conti- nent is less mysterious; scientists probing...