But nature has afforded our great Transatlantic rivals marvellous facilities for the development and rapid increase of vessels propelled by steam, not possessed by ourselves. The lakes[145] of America are, in fact, extensive inland seas, affording in themselves an almost unlimited source of profitable employment to vessels propelled by steam. Their shores are lined with sheltered bays and natural harbours, with waters unusually free from rocks and shoals, while, in their immediate vicinity, are vast tracts of rich lands requiring only the industry of man to render them subservient to his wants, while the surrounding forests at the same time produce some of the finest pine timber in the world. [Sidenote: Canals.] [Sidenote: Harbours.] Great cities, such as Chicago,[146] Buffalo, Detroit, Michigan, Milwaukie, Toronto, and Kingston, besides numerous towns and villages, now line their banks, while those lakes which have no natural navigable communication with each other are now connected by means of canals, so that vessels from the Atlantic can penetrate for upwards of 2000 miles into the interior, in fact, to the most remote habitable regions of North America.[147] Short canals, also, overcome the natural obstacles presented to navigation by the rapids of the St. Lawrence and the Falls of Niagara; and, while, on the one hand, the Erie canal of 363 miles in length connects that lake with the River Hudson, and consequently with the Atlantic Ocean, the Ohio Canal, 334 miles in length, on the other hand, brings it into connection with the Gulf of Mexico by way of the great rivers Ohio and Mississippi: thus, with the Welland Canal,[148] the connecting link between the other lakes and Ontario, there is navigable communication throughout the whole of the vast continent of North America, extending from the Gulf of St. Lawrence to the Gulf of Mexico, a distance of upwards of 3000 miles. All these lakes are now well supplied with lighthouses, buoys, and beacons to insure the safety of the large fleets of shipping employed on them. There are, also, numerous spacious harbours, many of them built of stone, as also breakwaters, the waves on these lakes during gales of wind being hardly less formidable to navigation than those of the ocean. [Sidenote: Rivers.]