Gerda stood quietly beside the rail, looking back at the island, long after Karen’s rainbow skirt and the lighthouse had faded from sight.

“I will give you two oere for your thoughts, if they are worth it,” her father said at last.

“I was thinking that it will make Karen sad to hear of my good times this winter,” Gerda told him.

“She will like to have your letters to think about,” replied Lieutenant Ekman cheerfully.  Then he pointed to a little town on the shore ahead.  “There is Lulea,” he said.  “You will soon be travelling on the railroad toward Mount Dundret and the midnight sun.”

But although Gerda was soon speeding into the mysterious Arctic regions, she could not forget her new friend in the lonely lighthouse.

CHAPTER V

CROSSING THE POLCIRKEL

“Polcirkel, Birger, Polcirkel!” cried Gerda from her side of the car.

“Polcirkel!” shouted Birger in answer, and sprang to Gerda’s seat to look out of the window.

The slow-running little train groaned and creaked; then came to a stop at the tiny station-house on the Arctic Circle.

The twins, their faces smeared with vaseline and veiled in mosquito netting, hurried out of the car and looked around them.  Close beside the station rose a great pile of stones, to mark the only spot where a railroad crosses the Arctic Circle.  This is the most northerly railroad in the world, and was built by the Swedish government to transport iron ore to the coast, from the mines four miles north of Gellivare.

As the two children climbed to the top of the cairn, Birger said, “This is a wonderful place; is it not, Gerda?”

His sister looked back doubtfully over the immense peat bog through which the train had been travelling, and thought of the swamps and the forests of pine and birch which lay between them and Lulea, many miles away on the coast.  Then she looked forward toward more peat bogs, swamps and forests that lay between them and Gellivare.

“I suppose it is a wonderful place,” she said slowly; “but it seems more wonderful to me that we are here looking at it.  Do you remember how it looks on the map in our geography, and how far away it always seemed?”

“Yes,” replied her brother, “I always thought there was nothing but ice and snow beyond the Arctic Circle.”

“So did I,” said Gerda.  “I had no idea we should see little farms, and fields of rye, oats and barley, away up here in Lapland.  Father says the crops grow faster because the sun shines all day and almost all night, too; and that it is only eight weeks from seed-time to harvest.

“No doubt there is plenty of ice and snow in winter; but just here there seems to be nothing but swamps and forests.”

“And swarms of mosquitoes,” added Birger.  “Don’t forget the mosquitoes!”

In a moment more the children were back in their seats, and the train was creeping slowly northward, on its way toward Gellivare and Mount Dundret, where, from the fifth of June to the eleventh of July, the sun may be seen shining all day and all night.