"Oh, yes," said Henry, who had been reading some of Captain Back's Adventures in the North seas, "and ships can sail between these masses, only they must take care not to get crushed among the ice, nor to stay too long, and to get frozen up for the winter. They must also be on the look-out for icebergs."

"What are icebergs?" asked Robert.

"They are great mountains of ice, as big as churches, floating about in the sea," replied his brother.

Mary wanted to know where the icebergs came from; but Henry could not tell her, and they therefore appealed to their father.

"Icebergs are formed by the glaciers, or icy streams, of polar regions. I shall soon have to explain to you the nature of the great glaciers of the European Alps. Slow-moving masses of ice, of a similar kind, are found in polar valleys, but instead of terminating on dry land they descend steep valleys, and terminate in the ocean. As the glacier comes near the sea, immense masses are broken off, and fall into the water with a noise like that of thunder. These are now icebergs of various shapes and sizes, and

oftentimes of great beauty, owing to the colours they reflect, and the purity of the ice of which they are composed. Captain Hudson has described

some which he saw in the Antarctic ocean, that is, near the south pole; and I think you will be glad

D

to read what he says."

Their father took down a book from one of the shelves, and after mentioning that some of these bergs were one-third of a mile long, and two hundred feet high, with sides perfectly smooth as if they had been chiselled, he requested Henry to read as follows:

"Others, again, exhibited arches of manycoloured tints, leading into deep caverns, open to the swell of the sea, which, rushing in, produced loud and distant thunderings. The flight of birds passing in and out of these caverns, recalled the recollection of ruined abbeys, castles, and caves, while here and there a bold projecting bluff, crowned with pinnacles and turrets, resembled some gothic tower. A little farther onwards would be seen a vast fissure, as if some powerful force had rent in twain these mighty masses. Every noise on board, even our own voices, reverberated from the massive and pure white walls. These tabular bergs are like masses of beautiful alabaster; a verbal description of them can do little to convey the reality to the imagination of one who has not been among them. If an immense city of ruined alabaster palaces can be imagined, of every variety of shape and tint, and composed of huge piles of

buildings grouped together, with long lanes or streets winding irregularly through them, some faint idea may be formed of the beauty of the spectacle."

"I am surprised to find that birds fly about in the icebergs," said Henry; "I should have thought it was too cold for birds in those seas.”

"Birds are to be seen in summer even in those desolate regions," replied his father; "but you must not suppose that icebergs always remain in the extreme north, or the extreme south, where they are formed. They are brought every season into more temperate latitudes, and they cool down the waters of our seas so much, that they are supposed to have great influence in making our winters more or less severe. Ships going to America frequently meet with icebergs in the North Atlantic, and are sometimes in danger of being crushed between two of them."

The children were surprised to find that the icebergs are such travellers, and they thought it would be pleasant to meet with them, if you could be sure of their keeping at a proper distance. Their father told them that there are fixed as well as floating icebergs; the former being attached to

the polar shores, and sometimes extending many miles in length.

Having thus explained what icebergs are, their father again directed their attention to his large map. They saw that the ocean is indeed one great body of water, and that there are no real divisions in it, although different names are given to different parts of it.

Mary asked to be shown the Gulf of Mexico, and she was pleased to find that the course of the Gulf-stream was marked by fine waving lines on the map, so that, with her papa's help, she was able to trace it from that gulf along the coast of Florida, and thence in a north-east direction until it approaches the shores of Newfoundland, where it meets a great current from the Arctic regions and turns suddenly towards the east; then bending southwards, reaches the Azores; after which, its course is less distinct, but appears to be in the direction of Madeira and the Canary islands.

"You told us, papa," said Henry, "that when we came to look at the map we should better understand why the waters of the Gulf-stream are So warm. Will you explain this to us, and also tell us how it is that such an enormous