Brothers Jeff and Adam Clink spent 20 minutes fiercely debating the capital of Australia while standing 10 feet from the family's World Book encyclopedia Monday. 'You're high,' Jeff, 18, told Adam. 'It's Sydney.' Adam, who said he is '99.99 percent sure' that Melbourne is the capital, conceded that one city might be the capital of the Australian continent and the other the capital of the nation. 