The battle was still with the giants, though, for no weapons could kill them. Mars threw his spears and they rebounded from the stone hearts of the giants. No one knew what would happen, for certain of the giants went down to the earth again and brought up hills with which to crush the habitations of the gods, but just then a great idea came to Apollo. He believed that there were unseen forces which were quite as powerful as the giants' trees and rocks and hills in deciding this battle. So Apollo sent Mercury, the messenger with winged shoes, post haste with a secret message to Helios who lived in the palace of the sun commanding him to close and lock the doors. There was no light for the giants to fight by and they were well known to be hulking, awkward creatures, very clumsy about using their hands and feet. They needed the light. They had even made attempts to steal the summer from mortals that they might have more sunshine themselves and they had succeeded in a way, for winter came upon the earth every year with its cold and shorter days. But the giants had neglected to bring any sunshine with them and it was suddenly as dark as night on Mount Olympus. The giants fumbled about and stumbled and fell upon their own weapons. Taking advantage of this temporary rout, Jupiter sent a sky full of thunderbolts into their midst and they tumbled back to earth again. It was odd, but Apollo, whom the giants had thought so unessential because he protected knowledge and the oracle of Delphi and the tender Muses, had conquered with his own special weapon, light. The giants were not particularly hurt by their fall; they were only driven out of the habitation of the gods and they began taking counsel together at once as to how they might begin their war all over again. But they suddenly discovered that they had nothing to eat. In their absence, Ceres had cut down and uprooted from the earth the herbs that they needed to keep them alive and preserve their strength. Then, to make sure that their destruction would be complete, Jupiter covered each giant with a volcano. Each was imprisoned fast underneath a mountain, and all he could do was to breathe through the top once in a while in a fiery way. That was the end of the giants. For a while they did some damage, particularly the giant Enceladus whom it took the whole of the volcano Aetna to cover and keep down. But gradually even the volcanoes became quiet and there was more peace upon the earth. Mortals, for all time, though, have followed the example of the giants and have tried to use their strength in battle for pillage. They have destroyed beautiful buildings and put out home fires and interfered with teaching and music and painting and writing, because they could not see the light shining in these. But what usually happens to them in the end is just what happened to the giants who started out to destroy Mount Olympus. They find that they have pulled a volcano down over their shoulders.