The St. Lawrence is of a fine cerulean hue, but, like its parent waters of Erie and Ontario, rapidly deposits lime and alumine, so that the boilers of steam-vessels, and even teakettles, soon become furred and incrusted. The specific gravity of the St. Lawrence water above Montreal is about 1·00038, at the temperature of 66°, the air being then 82° of Fahrenheit. It contains the chlorides, sulphates, and carbonates, whose bases are lime and magnesia, particularly and largely those of lime, which accounts for the rapid depositions when the water is heated.
A very accurate analysis gives, at Montreal, in July, atmospheric air in solution or admixture 446 per cent; for a quart of this water, 57 inches cubic measure, evaporated to dryness, left 2.87 solid residue.
| Grains. | |
| Sulphate of magnesia | 0·62 |
| Chloride of calcium | 0·38 |
| Carbonate of magnesia | 0·27 |
| Carbonate of lime | 1·29 |
| Silica | 0·31 |
| —— | |
| 2·87 |
The waters of the Ottawa, flowing through an unexplored country, are of a brown or dark colour. Their specific gravity is only (compared to distilled water) as 1·0024 at 66°, the temperature of the air in July being 82°.
The 57 cubic inches of this water gave
| 0·99 | sulphate of magnesia. |
| 0·60 | chloride of lime. |
| 1·07 | carbonate of magnesia. |
| 0·17 | carbonate of lime. |
| 0·31 | silica. |
| —— | |
| 2·87 |
The difference of the colours of these waters is so great, that a perfect line of distinction is drawn where they cross each other; and there can be no doubt that it is caused by the reflection of the rays of light from the impregnation of different saline quantities.
Thus as, in the old world, the waters of the Shannon are brown, and Ireland, speaking generally, as Kohl says, is a "brown" country;[8] so, in Upper Canada, St. Lawrence and the lakes are blue and green; and in Lower Canada, St. Lawrence and the Ottawa are brown of various shades, a very slight alteration of the chemical components reflecting rays of colour as forcibly and perceptibly as, in like manner, a very slight change of component parts develops sugar and sawdust. Nature, in short, is very simple in all her operations.
Before we proceed to the lower extremity of these wonderful sheets of water again, let us just for a moment glance at what is about to be achieved upon their surfaces, and place the Sault of St. Marie or St. Mary's Rapids, which separate Superior from Huron, before an Englishman's eyes. There at present nothing is talked of but copper mines and silver or argentiferous copper ores.
The Falls of St. Mary are only rapids of no very formidable character, the exit of Lake Superior into Lake Huron. Fifteen miles from the end of the Great Lake, as Superior is called, are the American village of St. Mary and the British one of the same name, on the opposite bank of the River St. Mary.