Harvey and Irma Schluter have been married for 75 years. He turned 104 in July; she will be 93 in November. They vividly remember many of the major events of the 20th century, from her first time spotting an airplane, during the Great Depression, to his wonder at watching Neil Armstrong walk on the moon. In a recent phone interview, Mrs. Schluter even recalled the weather near her home in Spokane, Wash., on the day that President John F. Kennedy was assassinated. (Cool and cloudy.) But never before have they seen two major hurricanes bearing their names threaten the United States.