The first officer nodded and crossed the bridge to repeat Roy’s report to the captain. Roy waited lest the captain should have an order. The latter merely nodded at the mate and peered into the storm again. Roy went back to the wireless house, clutching a hand-rail and staggering under the wind. He noticed that the ship was moving at half speed.

Again he called the City of Columbus. The reply seemed no sharper than before. But when he signaled the Merrimack, the answer fairly crackled in his ears. Evidently the two boats were much nearer to one another.

Roy’s heart began to pound furiously. Were the two ships about to collide? Was there anything he could do to prevent it? What should he do if they did? Sound the SOS of course and keep sending it until he sank. That was his duty. He set his teeth. “I’ll do it,” he muttered. “But there mustn’t be any collision. We must prevent it. But how?”

Roy’s brow wrinkled. What could he do? “If only I had a direction finder like the one the government gave us during the spy hunt,” he sighed, “I’d locate the Merrimack quick.”

Again he called. “KQM de WNA. How are my signals now?”

“WNA de KQM. Sharper than ever. We must be very close.”

“Are you whistling?” asked Roy.

“Sure. Can’t you hear us? We can hear you.”

Roy laid down his receivers and opened the door. Faintly he heard the booming of the Merrimack’s whistle. Then it came with startling distinctness. A third time it sounded apparently in the far, far distance. From what direction the sound came Roy had not the slightest idea. The fog now muffled, now magnified the sound, which seemed to come from nowhere and everywhere.

An idea flashed into Roy’s head. He leaped back to his operating table.