72 SCIENCE IN GRECO-ROMAN ANTIQUITY 



ducing any proof, are convicted of imposture since 

 they boast of having found a demonstration which is 

 in fact impossible" (Heiberg edition, II, p. 5). It 

 was likewise in Egypt, if Diodorus of Sicily is to be 

 believed, that Archimedes discovered the screw which 

 bears his name, called also a snail or spiral pump. 

 This pump consists of a tube open at both ends and 

 twisted like a corkscrew. When inclined to the 

 vertical and rotated on its axis, it raises the water 

 in which its lower extremity is immersed. It is 

 doubtful, however, whether such an apparatus had 

 not been used in Egypt before the time of Archimedes. 

 Similarly it is not known exactly by what means 

 Archimedes launched the huge ship which Hiero had 

 had built, and which the Syracusans could not move 

 from the slipway (Proclus, Comm., EucL, I, p. 63, 19). 

 According to Plutarch the machinery used was com- 

 posed of cords and pulleys, but the use of tackle had 

 been known from the time of Archytas. It is more 

 probable that it was an endless screw, working a 

 system of toothed wheels. 1 However this may be, 

 it was through meditating on the construction of 

 these engines that Archimedes was led to formulate 

 the exact laws of mechanics. The task which he 

 assigns to this science, namely, " to move a given 

 weight by a given force," is only the theoretical trans- 

 lation of the famous saying, " Give me but a place to 

 stand on and I will move the earth," which he uttered 

 at the time of the launching of the vessel, the difficul- 

 ties of which have been referred to. For this reason 

 it is very likely that the writings by which Archimedes 

 established the basis of rational mechanics (at least as 

 far as statics is concerned) belong to the first years 

 of his scientific activity. Perhaps it was also at this 

 time that he discovered the infinitesimal method of 

 integration, based on mechanics, which he used together 

 1 Ver Eecke, work quoted, p. xiii. 



