Press Herald: Twenty-five springs ago, U.S. Sen. George J. Mitchell of Maine put the finishing touches on a book called World on Fire, subtitled Saving an Endangered Earth. Mitchell had worked extensively on amendments to the Clean Air Act since he joined the Senate in 1980 and now, as majority leader hed just completed months of negotiating to get a reauthorized Clean Air Act through the Senate. The book, which addressed what Mitchell called the gathering environmental tragedy, sent out a clarion call...