Arch i me des

of Syracuse, the father of philosophy, and by far the greatest mat he and engineer of antiquity, was born 287 B.c. He was, according to Plutarch, a of King Hiero, and he certainly received patronage and support of that sovereign. He said to have visited Alexaudria in order to hear and to have begun his practical career by Egyptian marshes and embanking the The fragments of his works yet extant. extraordinary mathematical ability, dealing such subjects as the relations between the of a sphere and a cylinder; the measure of the area of a circle; the ratio of the cir to the diameter; the application of sections to solid geometry; the quadrature the parabola; the centre of gravity of planes;. the equilibrium of floating bodies. he prinof the lever was so thoroughly appreciated him that he is reported to have exclaimed, me a lever of sufficient length, and a point. rest it on, and I will move the earth.” When the under Mar cell us besieged Syracuse in B.c., he exerted himself actively to contrive for its defence, and set fire to the hostile by a combination of mirrors and burning He was killed during the a ault on the though Mar cell us had given special orders he was to be spared. Arch i me des' Principle, in Hydrostatics, the that a fluid exerts a resultant upward force any body immersed in it, exactly equal to the of the fluid displaced by the body. If, there the weight of the body be le than that of the displaced, there will be a tendency for it to upwards, as in the case of a. balloon. If equal the weight of fluid displaced, the body will remain rest in any position within the fluid. But if the body will tend to sink. [Sprcrric and HyDROSTATICS. ] Arch i me des’ Screw, © mechanical confor elevating water, named after its in- In its simplest form, this is a hollow placed in an oblique position with ita lower ree ARCH I ME DES’ SCREW, in water. When rotated about its axis, water at this end, and is lifted up by the screw 196 ( 180 eater es action. If the rotation were reversed, the water would be lowered again.