Principle of Displacement

The Principle of Displacement is a scientific principle put forth by Archimedes. It states that the upward buoyant force that is exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces and acts in the upward direction at the center of mass of the displaced fluid.

Supposedly, when Archimedes discovered the principle he exclaimed "Eureka."

Beast knew of the principle and heard the rumor of Archimedes's discovery. He mentioned the event when he hacked into the Mutant Control Agency computers.

Background
The principle is actually known as the Archimedes' Principle.