Another hnch of science which is, perhaps, the greatest contribution of Greek civilisation is mechanics. Mechanics developed out of the necessities of imgation, moving of heavy bodies, ship-building and making military equipment with known tools and methods. As the invading armies of Alexander came in contact with the craftsmen of the iniddleeastem countries, a number of inventions such as the pulley, windlass and screw came into use and were improved upon (Fig.). Archimedes (287-212 B.C.) aided this process of building machines by his ideas of forces having to balance each other to keep a body static (at rest). And his contribution to the study of floating bodies and hydrostatics is useful even today. Fig.: Some mechanical devices used in Greece: a) windlass and pulley for drawing water fran a well; b) crass-section of a water-raising qrew designed by Archimedes. widely used for imgation. Strip of wqal wm wrapped in a spiral on the edge of a round wooden bedm. This was then encased in boards. When placed in water and spun, it caused the water to climb the spiral and gush out.