By reason of its peculiar shape easy access is given to all parts of the republic, and the exploitation of its resources has been comparatively easy. In no place are the mountains far distant, and short spurs of railway connect the mineral deposits with the sea. Along the coast there are no fewer than fifty-nine ports, between which regular communication by steamer is carried on. Fourteen of these are ports of entry, in which customs houses are located, and the others are minor ports, at which only national coasting steamers stop. There are very many rivers in the country, but only a very few of them are any aid to navigation. They are mostly short streams which are formed by the melting snows of the Andes, and then rush onward toward the sea by a more or less direct route. The principal rivers are all in the southern half of the country. In the deserts of the northern section the waters formed by melting snows are evaporated or are absorbed by the parched soil long before they reach the sea. The Yelcho and Palena are the largest rivers of Chile. The latter is the longest, for it cuts through a pass in the Andes and runs back into Argentine territory for seventy-five miles. Others are the Maullin, Calle-Calle, Bio-Bio, Bueno and Maule. Some, such as the Bio-Bio and Maule, are navigable for short distances by vessels of shallow draft. Their importance to commerce is insignificant, however, when compared with the great rivers of the eastern coast. The Bio-Bio, for instance, is only one hundred and sixty miles long. They do furnish water for irrigation purposes, only a small portion of which has as yet been developed. There are several lakes in Chile, of which Llanquihue, Todos Santos, and Ranco are the most important. The two first mentioned have steam navigation.