“Say, rather,” said the teacher, “that by close observation and by comparison of observed facts, we may gather more or less valuable information. Pupils are too ready to depend for information rather upon memorizing what is in books than upon the cultivation of the faculties of observation. Now, the books are very valuable as giving us the knowledge amassed by many minds, and also they help us to reason judiciously upon what we see. But the information gathered from books is much more easily forgotten than that which comes to us from observation, and we must, in the study of natural science, yoke the book to practical observation, and closet study to out-of-doors study.” LESSON XV. THE WINTER OF THE WORLD. “Hark to that mighty crash! The loosened ice-ridge breaks away-- Seaward the glittering mountain rides, While down its green translucent sides The foaming torrents dash.” --BRYANT. Once upon a time the North Polar region, where all is now snow and ice, intense cold and six months of night, was a land of warmth and sunshine. At that time, how long ago it was we cannot tell, the North Polar Circle was a green and luxuriant flower-garden. The beech, oak, poplar, maple, and walnut grew there. The fragrant lime tree and the beautiful magnolia were there. Before this flora appeared, plants of the carboniferous era had flourished there,--pines, club-mosses, tree-ferns, cycads; and these had so abounded that a bed of coal thirty feet thick was laid down. Over this buried coal-bed the spruce, pine, fir, birch, cypress, elm, hazel, and viburnum grew in the Arctic zone. These trees were not the only representatives of the plant world; on the plains the grasses grew, on the ponds the water-lilies rocked, and reeds and sedges fringed in dainty beauty the borders of the pools. Many families of plants then growing in northern Greenland had at the same time their representatives in Central Europe. [Illustration: WHEN ICE WAS KING.] Evidently at that date the Arctic zone had a mild climate, and day and night of moderate length. That the above numerated plants and almost two hundred other species grew within nine degrees of the North Pole is proved by finding their remains in all stages of growth, from seed to matured plant, from root to fruit, scattered over an extensive area of country. How did this happen? What occasioned the change? How came Greenland then to be a warm and smiling land? These are questions to which no answer can at present be given. No one knows how this could have been.