"We have taken the prettiest of the spruces first," continued Miss Harson, "and now we must see what are the differences between them. 'The two species of American spruce, the black and the white--or, as they are more commonly called, the double and the single--are distinguished from the fir and the hemlock in every stage of growth by the roughness of the bark on their branches, produced by little ridges running down from the base of each leaf, and by the disposition of the leaves, which are arranged in spirals equally on every side of the young shoots. The double is distinguished from the single spruce by the darker color of the foliage--whence its name of black spruce--by the greater thickness, in proportion to the length, of the cones, and by the looseness of its scales, which are jagged, or toothed, on the edge.' It is a well-proportioned tree, but stiff-looking, and the dark foliage, which never seems to change, gives it a gloomy aspect. The leaves are closely arranged in spiral lines. The black spruce is never a very large tree, but the wood is light, elastic and durable, and is valuable in shipbuilding, for making ladders and for shingles. The young shoots are much in demand for making spruce-beer. The white spruce is more slender and tapering, and the bark and leaves are lighter. The root is very tough, and the Canadian Indians make threads from the fibres, with which they sew together the birch-bark for their canoes. The wood is as valuable as that of the black spruce."