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.

CHAPTER XXXIX
"ACCIDENTS WILL HAPPEN"

If anybody had observed the precipitation with which Irving dived down the hatchway of U-31 a moment or two after he recognized the "cubist art spy," there is no doubt that the observer would have been impressed with the mystery of the proceeding. As it was, all of his boche companions on the outer deck were too much interested in seeking an explanation of the "kamerad" cry from the midst of a boatload of enemy soldiers and sailors to give attention to anything less than the explosion of a bomb on their own vessel.

Irving meanwhile picked up a sou'wester that he found on the lower deck, put it over his head so that it partly covered, shaded, and hence considerably disguised his face, and then returned to the outer deck. True, the weather was not stormy, but the air was chilly and the "cloudburst hood" added considerably to his comfort.

The real Hessenburg had been assisted on board and was being questioned by Captain Bartholf. Irving heard the latter ask him his name, and then suddenly something happened which the trembling spy has ever since declared undoubtedly saved his life and some very important information for the Allies.

What caused the sudden lurch of the submarine was not subsequently disclosed. Possibly one of the men below, accidentally or thoughtlessly moved a lever or wheel that resulted in a momentary spasm of mechanical action. At any rate, all on the outer deck were dancing around for several seconds to preserve their balance, and one of them was not as successful as the others. That was Hessenburg, who was thrown violently against the low railing so that he struck his head on one of the iron standards or posts.

Evidently he was seriously injured, for he did not attempt to rise. The pallor of his face and the glassy look in his eyes indicated that he had fainted. He was carried below and restoratives were administered to him, but these did not bring back more than barely enough life to reassure his caretakers that the concussion on his head was probably not fatal.

* * * * *

The run from the scene of the sinking of the British hospital ship and convoy to the Spanish coast was made in about eighteen hours, and before noon of the day following, Irving was landed on a bleak and desolate spot on the Bay of Biscay. Meanwhile, he had thankfully observed the slowness with which the former "cubist art spy" recovered. Although he found it necessary several times to be at the bedside of the patient, the latter showed no signs of recognition; indeed, he at no time before Irving was put ashore indicated that he had fully recovered from the stupor which followed the shock of his fall.

The story of how Irving found his way to a Spanish settlement and subsequently got in touch with a British consulate and thence again with the Canadian army is of little interest compared with the thrilling events heretofore narrated. Suffice it to say that in due time success met his efforts to get back with the Canadians, who retained unshakable possession of Vimy Ridge, and that the information he was able to turn over to his superior officers brought him recognition and honors from very high sources.