Eudoxus and Archytas were the first who began to treat of this renowned science of mechanics, cleverly illustrating it, and proving such problems as were hard to understand, by means of solid and actual instruments, as, for instance, both of them resorted to mechanical means to find a mean proportional, which is necessary for the solution of many other geometrical questions. This they did by the construction, from various curves and sections, of certain instruments called mesographs. Plato was much vexed at this, and inveighed against them for destroying the real excellence of geometry by making it leave the region of pure intellect and come within that of the senses, and become mixed up with bodies which require much base servile labour. So mechanics became separated from geometry, and, long regarded with contempt by philosophy, was reckoned among the military arts. However Archimedes, who was a relative and friend of Hiero, wrote that with a given power he could move any given weight whatever, and, as it were rejoicing in the strength of his demonstration, he is said to have declared that if he were given another world to stand upon, he could move this upon which we live. Hiero wondered at this, and begged him to put this theory into practice, and show him something great moved by a small force. Archimedes took a three-masted ship, a transport in the king's navy, which had just been dragged up on land with great labour and many men; in this he placed her usual complement of men and cargo, and then sitting at some distance, without any trouble, by gently pulling with his hand the end of a system of pullies, he dragged it towards him with as smooth and even a motion as if it were passing over the sea. The king wondered greatly at this, and perceiving the value of his arts, prevailed upon Archimedes to construct for him a number of machines, some for the attack and some for the defence of a city, of which he himself did not make use, as he spent most of his life in unwarlike and literary leisure, but now these engines were ready for use in Syracuse, and also, the inventor was present to direct their working.