ancient mathematician who invented a namesake screw (used in irrigation). He tried to calculate how many grains of sand could fill the universe using a 'myriad' counting system in his book The Sand Reckoner. He used the method of exhaustion for calculating the area under a parabola and to approximate pi. His reputed last words were 'do not disturb my circles,' devised a gigantic claw and a heat ray consisting of parabolic mirrors to thwart a Roman siege of Syracuse. famous for saying 'Give me a place to stand on and I will move the Earth' and for shouting 'Eureka!' after discovering the principle of buoyancy. Famous for determining the ideal mechanical advantage for the lever. On Floating Bodies. The Quadrature of the Parabola