But the best gift was still to come,--a never-to-be-forgotten gift that came on that wonderful night of their twelfth birthday. All day there had been a strange feeling in the air. When the girls brushed their hair in the morning it was full of tiny sparkles and stood out from their heads like clouds of gold, and Birger had found, early in the day, that if he stroked the cat's fur it cracked and snapped like matches, much to Fru Kitty's surprise. Now, when Gerda went to look out of the window, she called to the others to come quickly to see the northern lights; for out of the north there had come a gorgeous illumination, filling the heavens with a marvellous radiance such as only the aurora borealis can give. Banners of crimson, yellow and violet flamed and flared from horizon to zenith; sheets of glimmering light streamed across the sky, swaying back and forth, and changing from white to blue and green, with once in a while a magnificent tongue of red flame shooting higher than the others. "It is a carnival of light," said Gerda, in a tone of awe. She had often seen the northern lights, but never any so brilliant as these. Everyone seemed charged with the electricity, and little Karen said softly, "I never felt so strange before. The lights go up and down my back to the tip of my toes." "It is the elves of light dancing round the room," said Birger with a laugh. "No," said Gerda, "it is the Tomtar playing with the electric wires." Then, as they all stood watching the wonderful display in the heavens, the door opened and Lieutenant Ekman came into the room. "Here is a letter for Karen from her mother," he said; "I have had it in my pocket all day." "Oh, let me see it," said Karen, and she turned and ran across the room. Yes, ran,--with her crutch standing beside the chair at the window, and her two feet pattering firmly on the floor. "Look at Karen," cried Gerda. "She has forgotten her crutch!" Karen held her mother's letter in her hand, and her two eyes were shining like stars. "I feel as if I should never need my crutch again," she said. Then she turned to Fru Ekman and asked breathlessly, "Do you believe that I will?" "I am sure that you won't," replied Fru Ekman, stooping to kiss the happy child. "I have noticed for a long time that your back was growing straighter and stronger, and you were walking more easily." Gerda clapped her hands and ran to throw her arms around her friend. "Oh, Karen," she exclaimed, "this is the best birthday gift of all! The Tomtar sent it on the electric wires." "No," said Birger, "it was the elves of light dancing across the room." But Karen looked at the little family clustered so close around her. "It is my crown of joy and is from each one of you," she said; "but from Gerda most of all." CHAPTER XV THE MIDSUMMER FESTIVAL