"Oh, Gerda, how I wish I were going with you," said Hilma wistfully. "I should love to cross the Arctic Circle and see the sun shining all night long." Gerda, who was wearing a pretty blue travelling dress, with blue ribbons on her hat and in her hair, threw her arms around her friend. "I wish you were going, too," she answered. "Birger is the best brother any girl could have; but he isn't like a sister, and that is what you are to me, Hilma." At the same moment, Birger was confiding to his friend, "I wish you were going with us, Oscar. Gerda is a good sister; but she isn't like a brother." All the other boys and girls were talking and laughing together, telling of the strange sights that Birger and Gerda would see on their trip into Lapland; and what they would do if only they were going, too. Suddenly a warning whistle from the steamer sent them hurrying back to the quay, where they stood waving their handkerchiefs and shouting good wishes until the twins were out of sight. The vessel's course lay first between two islands, and Gerda lifted her eyes to the windows of the King's Palace, which stood near the quay of one; but Birger found more to interest him in the military and naval buildings on the other. "There is a ship from Liverpool, England," said Lieutenant Ekman, pointing to a vessel which was lying beside the quay in front of the palace. "It is hard to believe that we are forty miles from the ocean when we see such big ships in our harbor," said Birger. "How did it happen that Stockholm was built so far from the open sea? It would be easier for all these vessels if they didn't have to come sailing up among all the islands to find a landing-place." "Lake Mälar was the stronghold of the ancient Viking warriors," replied his father; "and it was just because there were forty miles of difficult sailing among narrow channels, that they chose to live at the head of the Saltsjö, and make this fjord their thoroughfare in going out to the Baltic Sea." "Did they like to make things as hard as possible for themselves?" asked Gerda with interest. "Not so much as they liked to make it as hard as possible for their enemies," said Herr Ekman. "Centuries ago, hunters and fishermen built their rude huts on the wooded islands at the outlet of Mälar Lake. They often found it convenient to slip away from their pursuers among these islands; but they were not always successful, for their settlements on the site of the present city were repeatedly destroyed by hostile tribes." "Why didn't they build fortifications on the islands and hold the enemy at bay?" questioned Birger. "They were too busy sailing off to foreign lands," answered his father. "Fleet after fleet of Viking ships sailed out of the bays of Sweden, manned by the bravest sailors the world has ever known; and they swooped down upon the tribes of Europe, fighting and conquering them with the strength of giants and the glee of children."