“What do you mean?” asked Jensen, struck by this sudden change from his friend’s ordinarily meek demeanour. “What has it to do with you?”

Lyngstrand turned to him with a bitter little laugh. He seemed, indeed, a different man.

“More than you think, my friend,” he said, briefly. “I am not good company for U-boat commanders!”

“But why?—You lost no one——?”

Lyngstrand’s serious eyes held his.

“You remember I went to America in 1917, Jensen? I met a girl there—we were betrothed. She was coming to Europe to me last year. She never arrived. Her ship—a neutral—a small Norwegian ship, the Trondhjem, on which I had arranged for her passage—was torpedoed in the Atlantic last September—spurlos versenkt!” He finished in a tone of bitter mimicry, and then suddenly hid his face in his hands through a silence which Jensen felt incapable of breaking. At last he looked up again. “If ever I trace the scoundrel who murdered her——!” The ugly menace in his voice supplied the final clause to his unfinished sentence.

“A difficult task!” murmured Jensen, sympathetically.

Lyngstrand glanced at the closed drawer of the locker.

“When I think that perhaps on that chart—one of those little red crosses——” He crashed his hand upon the table. “By God, Jensen! I would give something to have another look at it!”

Jensen laid a friendly hand on his shoulder.