At five o’clock the three children were all at home again, and dressed for the party which the twins had every year on their birthday.

“It is time the girls and boys were here,” said Gerda, standing before the mirror in the living-room to fasten a pink rose in the knot of ribbon at her throat.

“Here they come!” cried Birger, throwing open the door, and the twelve children who had come before, bringing packages for the surprise box, came again,—­this time with little birthday gifts for the twins.

For an hour there was the greatest confusion, with a perfect babel of merry voices and laughter.  The gifts were opened and admired by everyone.  Gerda put on her fur coat and cap, Birger showed a fine new pair of skates which his father had given him, and Karen brought out a box of little cakes which her mother had sent for the party.

But when the children formed in a long line and Fru Ekman led the way to the dining-room, their excitement knew no bounds.

The table was a perfect bower of beautiful flowers.  There was a bouquet of bright blossoms at every plate, and long ropes of green leaves and blossoms were twined across the table, in and out among the dishes.  At Gerda’s place there was a wreath of violets, with violet ribbons on knife, fork and spoon; a bunch of violets was tucked under her napkin, and a big bow of violet ribbon was tied on her chair.

Birger’s flowers were scarlet pinks, with scarlet ribbons and a scarlet bow; and at the two ends of the table were the two birthday cakes, almost hidden among flowers and wreaths, with Birger’s name on one and Gerda’s on the other, done in colored candies set in white frosting.

Another happy hour was spent at the table, and then the guests trooped away to their homes, leaving the twins to look over their gifts once more.

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.