"Kattegat! Skager-Rak!" shouted Karl, who liked something in the sound of the words. "Grenen's great! But, honest, Valdemar, never in my life did I expect to bathe in both these raging seas at once! But here I go--look now!" and he plunged out into the breakers. Frederik dashed after him to make sure that he was safe, then came bounding back again to Valdemar. "Ow! ow!" cried Karl, limping back on one foot. "Crabber?" inquired Valdemar. "Uncle Thor warned us to look out for crabs and shrimps up here on the beach. You sit down here and rest, Karl. I'm going to gather some of those fine sea-gull's feathers scattered along the beach for you to take back home with you for your collection of Danish souvenirs. It was mighty nice of Uncle Thor to give you that letter from King Frederik!" "And I'm going to put my shoes and stockings right back on again while you're gone!" said Karl, surveying his painful foot with a frown. "Oh, look, Karl!" exclaimed Valdemar, as he soon came running back, his arms full of something. "Look what I've found for you! Sea-gulls' eggs! All greenish, with brown peppery spots on them, and here's a lot of the loveliest white wing-feathers, every one tipped with black! They're all for you, Karl." "Oh, thank you, Valdemar. Let's blow the eggs. Do you know how?" "Yes, of course. I've got a piece of wire in my pocket. You just run this wire straight through both ends--so! Then blow and blow!" Together the boys had soon blown all the eggs, and tied them up with the feathers in a piece of old fish-net they found on the beach. Then Karl watched Valdemar while he made a hasty sketch of Skagen Fyr, the great white lighthouse towering above the sand-hummocks near the Signal Station, where it is said that every year seventy thousand ships are signalled. As they started on their two-mile tramp over the desolate sand-ridges back to Skagen, Valdemar gave one last lingering look towards the wild, wind-swept stretch of endless beach they were leaving, where the North Sea and the Baltic have battled against each other for countless ages, with one ceaseless roar. Back of them, range after range of low shifting sand-dunes glistened in the sun, as they stretched towards the unbroken horizon in every direction. It was a strange new world to both boys. "What are you thinking so long about, Valdemar?" asked Karl. "Oh, Karl, it was off there that our noble Tordenskjold's little frigate, _White Eagle_, pursued the great Swedish man-of-war _Ösel_, and made her fly in terror. There's something about the very desolation of this place that, I like," said Valdemar. "Something strange, and picturesque, and romantic, I mean, Karl. One feels some way--up here at the Gren--as though he had actually reached the world's end! I'd like to come back up here often. Wouldn't you, Karl?"