The great lakes of the St. Lawrence basin cover a surface of nearly 100,000 square miles--an area larger than that of Great Britain. Lakes Ontario and Erie, connected by the Niagara river, continue the direct line of the St. Lawrence, Lake Erie more especially lying due south-west and north-east; but from the extreme end of this last-named lake the channel of communication takes a sharp curve to the north in the Detroit river, Lake St. Clair, and the St. Clair river, which link together Lakes Erie and Huron. Lake Huron, the centre of the whole group, stretches back towards the east and south-east in Georgian Bay, while on the north-west it is connected with Lake Michigan by the straits of Michillimackinac or Mackinac, and with Lake Superior by St. Mary's straits and rapids, the Sault St. Marie. The rivers which feed Lake Superior are the head waters of the St. Lawrence, and one of them, the St. Louis, which enters the lake at its extreme western end, has its source hard by the source of the Mississippi. The total length of lake and river on the line of the St. Lawrence is over 2,000 miles. [Sidenote: _The route of the Ottawa river._] It has been said that Lakes Ontario and Erie continue the main course of the St. Lawrence in its south-westerly and north-easterly direction, that the channel which feeds Lake Erie at its western end comes down from the north, and that the central lake which is then reached--Lake Huron--breaks back towards the east. Thus the direct line from Montreal to the centre of the lake system is not up the St. Lawrence, but along one of its largest tributaries, which enters the main river at Montreal. This tributary is the Ottawa, flowing {52} from the north-west in a course broken by falls and rapids. One hundred and thirty miles from its confluence with the St. Lawrence, just below the Chaudière falls, now stands the city of Ottawa, the capital of the Canadian Dominion, connected with Lake Ontario by the Rideau canal; and rather under 200 miles above Ottawa, where the Mattawa river enters from the west, there is nearly continuous water communication in a due westerly direction with Lake Nipissing, which lake is in turn connected by the French river with the great inlet of Lake Huron known as Georgian Bay. Champlain early explored this route--the direct route to the west, and along it as far as Lake Nipissing now runs the Canadian Pacific Railway. French river flows into the northern end of Georgian Bay. At its south-easternmost end, that bay runs into the land in the direction of Lake Ontario; and in the middle of the broad isthmus between the two lakes lies Lake Simcoe. [Sidenote: _Canada a geographical federation._]