This period is rendered additionally remarkable by the siege of Syracuse, which eventually fell into the hands of M. Claudius Marcellus, whose efforts had long been thwarted by the genius of Archimedes. This illustrious inventor lived to the good old age of seventy-five; but how he lived so long is a matter of almost as much wonder as some of his inventions, for his biographers tell us that he always forgot to eat and drink; nor could he ever be persuaded to take a bath, except when his friends pushed him into one. Even when this was accomplished, he was sure to be found under the ashes of the fire-places, writing problems among the cinders, and endeavouring to sift some important point; so that a bath was really thrown away upon the great philosopher. In a visit to Egypt, he became anxious to elevate the Nile to a certain point; but he remained in Egypt until all his money was spent, for the philosopher had never thought of raising the wind while intent on raising the water. He invented a screw, which still bears his name; but he is said to have amused himself, during the siege of Syracuse, by sitting at the window and inventing all sorts of missiles to hurl at the ships of the enemy. One day he might be seen throwing stones from a newly-invented sling, and a few days after he was found casting out chains, to pull--with a tremendous hook--the ships of the foe completely out of the water. He was so intent upon everything he came near, that he gave a lift to enemies occasionally as well as to friends, as in the instance just recorded, and he declared his ability to give the whole world a lift if he could only find a convenient spot in the neighbourhood for himself and his lever to rest upon. That in one sense he carried out his boast, we are willing to admit; for he undoubtedly elevated the world by raising the standard of science, and he exalted the whole of civilised humanity by his great discoveries. The part he took in the siege of Syracuse has been underrated by some, and exaggerated by others; for though the story of his pulling the ships out of the sea requires a length of rope, and other apparatus, which none but the greatest stretch of imagination can supply, his destroying the vessels by burning-glasses is perfectly credible. He is supposed to have used very powerful reflectors, capable of taking effect within the distance of bow-shot; and though for some time the moderns insisted that the long-bow had been pulled for the purpose of increasing the space, the powers of the burning-glass are now familiar to every schoolboy.