Neutral buoyancy diver maintains neutral buoyancy by continuous correction, usually by controlled breathing, as neutral buoyancy is an unstable condition for a compressible object in a liquid. The mathematician Archimedes discovered much of how buoyancy works more than 2000 years ago. In his research, Archimedes discovered that an object is buoyed up by a force equal to the weight of the water displaced by the object. In other words, an inflatable boat that displaces 100 pounds (45 kilograms) of water is buoyed up by that same weight of support. An object that floats in the water is known as being "positively" buoyant.
The Legend of Zelda: A Link to the Past his quest. Series antagonist Ganon remains sealed in the Dark World. It is revealed late in the game that Agahnim is an avatar of Ganon, used by the King of Evil to infiltrate the Light World. "A Link to the Past" is a prequel to the original "The Legend of Zelda" and "". At the beginning of the game, a young boy named Link is awakened by a telepathic message from Princess Zelda, who says that she is locked in Hyrule Castle's dungeon. As the message closes, Link finds his uncle ready for battle, telling Link to remain in bed.