through the hull, Archimedes' screw was purportedly developed in order to remove the bilge water. Archimedes' machine was a device with a revolving screw-shaped blade inside a cylinder. It was turned by hand, and could also be used to transfer water from a body of water into irrigation canals. Archimedes' screw is still in use today for pumping liquids and granulated solids such as coal and grain. Described in Roman times by Vitruvius, Archimedes' screw may have been an improvement on a screw pump that was used to irrigate the Hanging Gardens of Babylon. The world's first seagoing steamship with a screw propeller was the SS Archimedes, which was launched in 1839 and named in honor of Archimedes and his work on the screw. Archimedes' claw Archimedes is said to have designed a claw as a weapon to defend the city of Syracuse. Also known as "", the claw consisted of a crane-like arm from which a large metal grappling hook was suspended. When the claw was dropped onto an attacking ship the arm would swing upwards, lifting the ship out of the water and possibly sinking it. There have been modern experiments to test the feasibility of the claw, and in 2005 a television documentary entitled Superweapons of the Ancient World built a version of the claw and concluded that it was a workable device. Heat ray Archimedes may have written a work on mirrors entitled Catoptrica, and later authors believed he might have used mirrors acting collectively as a parabolic reflector to burn ships attacking Syracuse. Lucian wrote, in the second century AD, that during the siege of Syracuse Archimedes destroyed enemy ships with fire. Almost four hundred years later, Anthemius of Tralles mentions, somewhat hesitantly, that Archimedes could have used burning-glasses as a weapon. The presumed device, often called the "", focused sunlight onto approaching ships, causing them to catch fire. In the modern era, similar devices have been constructed and may be referred to as a heliostat or solar furnace. Archimedes' purported heat ray has been the subject of an ongoing debate about its credibility since the Renaissance. René Descartes rejected it as false, while modern researchers have attempted to recreate the effect using only the means that would have been available to Archimedes, mostly with negative results. It has been suggested that a large array of highly polished bronze or copper shields acting as mirrors