SUPERIOR, LAKE, the largest body of fresh water in the world, is the highest and most western of the great lakes lying between West Canada and the United States. It is situated not far from the center of the North American continent. Its general form is nearly semi-lunar, the outer curve being towards the north. Greatest length from e. to w., 355 m.; greatest breadth, 160 m.; area, about 3,200 sq.m.—fully that of Ireland. The surface of the lake i' about 600 ft. above the level of the sea, and its mean depth 1000 ft., so that its bottom 400 ft. below the level of the sea. Its surface has an eleva tion of about 22 feet above :hat of lake Huron and lake Michigan. The greater portion of this rise is at the Sault Ste. Marie, a strong rapid about a mile in length, at ,the com mencement of the river St. Mary, which transmits the waters of lake Superior to lake Huron.
Lake Superior, being situated very near the water-shed between Hudson's bay and the Mississippi, receives no rivers of importance, although hundreds of small rivers pour themselves into it. The largest are the St. Louis river, which falls into its western extremity at Fond du Lac, and is about 110 m. long; and the Neepigon river, on the n. side, which, with the lake of the same name, has a length of about 200 miles. One of the branches of the Mississippi in Minnesota approaches to within 20 m. of the western extremity of lake Superior; and a small lake near the head of the Albany river. of which the waters flow to Hudson's bay, is only 4 m. from a bay opposite the State islands on the northern shore, forming a route with little portage, which has long beer. used by the Hudson's Bay company, for the conveyance of goods from lake Superior to the northern country.
The promontory Kee-wee-naw, near the middle of the a. side, projects far into the lake. The islands are not numerous, the largest being Isle Royale, 44 m. long.
The country around lake Superior is generally bold and hilly, with the exception of the peninsula lying between it and lake Michigan; but few of the hills rise more than 1000 ft. above the level of the lake, and most of them are far below this height. On the
southern shore, 100 m. w. of the Saute Ste. Marie, are the Pictured rocks, cliffs of gray and red sandstone, from 100 to 200 ft. high, in many places presenting fantastic forms, and marked by numerous perpendicular stripes of red and yellow, from ferruginous waters trickling down the face of the rock.
The boundary between the United States and West Canada, starting from the outlet of the lake at the Sault Ste. Marie, sweeps toward the n., so as to include in the United States even the Isle Royale, which is only 13 m. from the British coast, and strikes inland from the mouth of Pigeon or Arrow river, on the n.w. shore.
The only obstacle to navigation between lake Huron and lake Superior is the Sault Ste. Marie, which is overcome by a canal of about a mile in length, with two locks, on the American side, This is, perhaps, the finest canal in the world. The sides and bot tom are lined with stone throughout its whole length, the locks are admirably contrived, and the largest ships can pass through it with case. The trade is increasing so rapidly that a canal on the British side will also be required at no distant day.
The water of lake Superior is remarkable for its coldness, purity, and transparency, although the affluents on both sides are either turbulent or deeply colored by vegetable matter from swamps and forests.
A rise or fall in the level of the water, amounting to several inches in a few hours, is frequently to be observed along the shore, and has been supposed to be due to a regu lar tide, but is probably caused by the wind. Fresh water being more easily moved by the wind than salt water, great waves arise in lake Superior with wonderful rapidity; and even in summer, large steamers are compelled to take shelter in some bay, or under the Ice of an island. Owing to the low temperature of the water, compared with that of the air, in summer, fogs are prevalent, resting on the water at night, and vanishing an hour or two after sunrise.