Mr. Ballard spoke to a luncheon audience about his work as an undersea explorer, including his discovery of the wreck of the Titanic in the northern Atlantic, his work in Guadacanal locating sunken military ships, and his upcoming plans to locate the wreck of the Lusitania. Following his prepared remarks, Mr. Ballard, who works at the Woods Hole Oceanographic Institute, responded to questions from members of the audience.