Leaving his animal atmosphere behind him, Pytheas returned to Orcas and from thence to Cantium. Instead of following his former track through the British Channel homeward, he turned to the eastward, and arrived, in a few days' sail, at the mouth of the Rhine. He found the country here inhabited by a race of fierce barbarians. Upon the shores of a vast gulf, beyond, dwelt the Teutons and the Guttones. In this gulf was an island named Abalcia, upon whose shores the waves deposited, in spring, immense quantities of yellow amber, which the inhabitants burned instead of wood, or sold for fuel to their neighbors the Teutons. Pytheas pursued his voyage as far as a river named Tanais, now supposed to be either the Elbe or the Oder. He considered this stream to be the eastern boundary of Celtica, in which he included Germania. He now turned his face homeward, and, coasting along the shores of Celtica and Iberia, arrived without accident or adventure at Massilia. He had sailed one hundred and eighty-six thousand stadia, or eleven thousand miles: the duration of the expedition was less than a year. Geographers subsequent to Pytheas strove zealously to discredit his assertions. One denied the voyage altogether; another questioned the veracity of the narrative. Strabo was particularly hostile to Pytheas, whom he said he would prove "a liar of the first magnitude." He was thus led to make long quotations from his descriptions for the purpose of refuting them. As the original account given by Pytheas is not extant, the world is indebted to the skepticism of Strabo for all that it knows of one of the most interesting and daring maritime enterprises of antiquity.