Birger took a tiny stone from his pocket and showed it to his sister, saying, “See my souvenir of Polcirkel.”  But Gerda paid little attention to his souvenir, and slipped over to her father’s seat to ask a question.

“Father,” she said softly.

Lieutenant Ekman looked up from the maps and papers in his lap.  “What do you wish, little daughter?” he asked.

“Will you please make me a promise?” she begged.

“If it won’t take all my money to keep it,” he answered with a smile.

But Gerda seemed in no hurry to tell what it was that she wanted, and began looking over the papers in his lap.  “What is this?” she asked, taking up a small blue card.

“That is my receipt from the Tourist Agency,” he answered.  “When I give it to the station master at Gellivare, he will give me a key which will open the hut on Mount Dundret, and let us see the midnight sun in comfort.”

“How much did you pay for it?” was Gerda’s next question.

“I paid about four kronor for the card and all the privileges that go with it,” was the answer.

“Have you plenty of money left?” asked the little girl.

Her father laughed.  “Enough to get us all three back to Stockholm, at least,” he said.  “Why do you ask?”

“Because—­” said Gerda slowly, and then stopped.

“Because what?” Lieutenant Ekman asked again.

“Because I wondered if we could stop at the lighthouse on our way home and ask Karen Klasson to go to Stockholm and live with us;” and Gerda held her breath and waited for her father to speak.

“Perhaps she would not like to leave her father and mother for the sake of living with us,” he said at last.

“I think she would, if it would make her back well,” persisted Gerda.

Herr Ekman laughed.  “If living with us would cure people’s backs, we might have all the lame children in Sweden to care for,” he said.

“But I want only Karen,” said Gerda; “and I thought it would be good for her to take the Swedish medical gymnastics at the Institute in Stockholm, where so many people are cured every year.”

Lieutenant Ekman looked thoughtfully at his daughter.  “That is a good idea and shows a loving heart,” he said.  “But are you willing to give up any of your pleasures in order to make it possible?”

Gerda looked at him in surprise, and he continued, “I am not a rich man.  If we should take Karen into our family and send her to the gymnasium, it would cost a good many kronor, and your mother and I would have to make some sacrifices.  Are you willing to make some, too?”

Gerda gazed thoughtfully across the stretches of bog-land to the forest on the horizon.  “Yes,” she said at last; “I will go without the furs Mother promised to buy for me next winter.”

Lieutenant Ekman knew well that Gerda had set her heart on the furs, and that it would be a real sacrifice for her to give them up; but if she were willing to do so cheerfully, it meant that she was in earnest about helping her new friend.