"Shut off the power."
Irving was in the conning tower with Capt. Bartholf and Lieut. Voltz of U-31 when the latter, who was at the periscope, gave the foregoing order through the speaking tube.
They had been out all night and half the preceding day, running much of the time on the surface of the ocean in order to make the best possible speed. Irving had not a clear idea where they were, but presumed that they must have passed a considerable distance beyond the western end of the English channel.
Lieut. Voltz gazed again into the glass of the periscope after giving his order to the engineer. He had had his hand on the lever at his right and with this had turned the periscope tube so that his eye could sweep the horizon. Now, however, he had discovered something, and he no longer moved the lever except occasionally little more than a hair's breadth in order to keep the object of interest in view. After a few moments of further careful examination and reference to the telemeter attachment to determine the distance away of the discovered object, he called again into the speaking tube.
"Go down four fathoms."
Then turning to Capt. Bartholf, he said:
"There are two vessels about five knots a little south of west from here. One is probably a convoy."
"Run about three knots closer and take another peep," the captain ordered. "Did 17 and the 23 sight them also?"
"I think so. Seventeen just went under."
Irving understood this question and answer to refer to two other U-boats that accompanied No. 31 on this trip. Meanwhile the latter submerged to the depth ordered by Lieut. Voltz.
Twenty minutes later the periscope was again a few feet out of the water with the lieutenant's eye glued to the glass and his right hand working the lever.
"Let me have a look," said the commander.
He gazed a minute into the glass and then said:
"I'm going to try to get that convoy first and then the other, which appears to be a hospital ship."
Irving shuddered.
The order was again given to submerge. The lieutenant seemed to be doing all the work of lookout, pilot and operating master, for he was busy at the steering wheel, periscope, and speaking tube almost simultaneously much of the time. All these were within easy reach from one position. The "sub" arose several times near enough to the surface to enable the lieutenant or the captain to take a peep at the prospective prey, and then down again it would go. At last, under direction from the captain, the lieutenant gave this order through the speaking tube:
"Have the men slide a torpedo into one of the forward tubes."
Eager to witness this operation, Irving sprang to the stairway and was soon down on the lower deck. There he saw several members of the crew remove the safety attachment from the nose of a sixteen-foot phosphor-bronze torpedo, which was seventeen or eighteen inches in diameter, and slide it into a tunnel-like hole in the midst of a maze of operating machinery. A minute or two later the order was given to "shoot," and out it went, under initial propulsion from a compressed air engine.
Then the order to submerge was given again, and away they went southward at full speed under three fathoms of water. Ten minutes afterward the periscope peeped up over the surface of the sea once more, and Capt. Bartholf had his eye glued eagerly to the glass.
A moment later he gave a yelp of delight, and Irving knew that a hit had been scored.
"We've hit 'em both fine!" the commanding officer exclaimed. "One of the other boats must have fired a torpedo about the same time we did. Both of those ships are going down."
It was not regarded safe to show the hulks of the submarines above the water yet, however, for fear lest the convoy hit one or more of them with a shell as a last living act of revenge. But they did not have to wait long, however, for the doomed vessels sank rapidly.
Then all three submarines showed themselves on the surface and Irving was delighted to observe that apparently all of the sailors, soldiers and nurses that had been on the hospital ship and the convoy were now in lifeboats, which were being rowed with frantic desperation away from the U-boat-infested spot.
"Follow them up and let's see what they look like," Capt. Bartholf ordered, with a kind of gloating glee.
All three captains seemed to be of like mind, for all three U-boats took the same course and ran up close to the crowded lifeboats. Several officers and members of the crew of each of the submarines appeared on the outer deck to view the results of their uncontested victory.
Suddenly there came from one of the boats a call that thrilled and chilled Irving with a sense of awed familiarity.
"Kamerad!"
Where had he heard that cry in that tone of voice before? He could not decide on the moment, and yet he was apprehensive of an unpleasant discovery.
The captain of U-31 determined to investigate and ordered the lifeboat from which the hail proceeded to come alongside. The occupants could do nothing more sensible than obey. As it approached a young man with an empty left sleeve arose and repeated his appealing cry, and Irving almost dropped in his tracks.
The one-armed fellow was Adolph Hessenburg, alias Tourtelle, the former Canadian lieutenant of the tattooed cubist art cryptogram. Undoubtedly he was being sent to England to be held there for a determination of his fate after information had been received regarding the success or failure of his substitute spy's mission within the German lines.