That these islands had already been visited by Himilco the Carthaginian seems fairly certain. He had started from Cadiz for the north when Hanno started for the south. From the Tin Islands his fleet had ventured forth into the open sea. Thick fogs had hidden the sun and the ships were driven south before a north wind till they reached, though they did not know it, the Sargasso Sea, famous for its vast plains of seaweed, through which it was difficult to push the ships. "Sea animals," he tells us, "crept upon the tangled weed." It has been thought that with a little good fortune Himilco might have discovered America two thousand years before the birth of Columbus. But Himilco returned home by the Azores or Fortunate Islands, as they were called. Leaving the Tin Islands, Pytheas voyaged on to Cape Finisterre, landing on the island of Ushant, where he found a temple served by women priests who kept up a perpetual fire in honour of their god. Thence Pytheas sailed prosperously on up the English Channel till he struck the coast of Kent. Britain, he announced, was several days' journey from Ushant, and about one hundred and seventy miles to the north. He sailed round part of the coast, making notes of distances, but these are curiously exaggerated. This was not unnatural, for the only method of determining distance was roughly based on the number of miles that a ship could go in an hour along the shore. Measuring in this primitive fashion, Pytheas assures us that Britain is a continent of enormous size, and that he has discovered a "new world." It is, he says, three cornered in shape, something like the head of a battleaxe. The south side, lying opposite the coast of France, is eight hundred and thirty-five miles in length, the eastern coast is sixteen hundred and sixty-five miles, the western two thousand two hundred and twenty-two--indeed, the whole country was thought to be over four thousand miles in circumference. These calculations must have been very upsetting to the old geographers of that age, because up to this time they had decided that the whole world was only three thousand four hundred miles long and six thousand eight hundred broad. He tells us that he made journeys into the interior of Britain, that the inhabitants drink mead, and that there is an abundance of wheat in the fields. "The natives," he says, "collect the sheaves in great barns and thrash out the corn there, because they have so little sunshine that an open thrashing-place would be of little use in that land of clouds and rain." He seems to have voyaged north as far as the Shetland Islands, but he never saw Ireland.