tested to the utmost the discipline of the mystery ship. The captain had two alternatives: he could fire at the submarine through the smoke, taking his chances of hitting an unseen and moving target, or he could wait until the enemy passed around the ship and came up on the other side, where there would be no smoke to interfere with his view. It was the part of wisdom to choose the latter course; but under existing conditions such a decision involved not only great nerve, but absolute confidence in his men. For all this time the fire at the stern was increasing in fierceness; in a brief period, Captain Campbell knew, a mass of ammunition and depth charges would explode, probably killing or frightfully wounding every one of the men who were stationed there. If he should wait until the U-boat made the tour of the ship and reached the side that was free of smoke the chances were that this explosion would take place before a gun could be fired. On the other hand, if he should fire through the smoke, there was little likelihood of hitting the submarine.
Those who are acquainted with the practical philosophy which directed operations in this war will readily foresee the choice which was now made. The business of mystery ships, as of all anti-submarine craft, was to sink the enemy. All other considerations amounted to nothing when this supreme object was involved. The lives of officers and men, precious as they were under ordinary circumstances, were to be immediately sacrificed if such a sacrifice would give an opportunity of destroying the submarine. It was therefore Captain Campbell's duty to wait for the underwater boat to sail slowly around his ship and appear in clear view on the starboard side, leaving his brave men at the stern exposed to the fire, every minute raging more fiercely, and to the likelihood of a terrific explosion. That he was able to make this decision, relying confidently upon the spirit of his crew and their loyal devotion to their leader, again illustrates the iron discipline which was maintained on the mystery ships. The first explosion had destroyed the voice tube by means of which Captain Campbell communicated with this gun crew. He therefore had to make his decision without keeping his men informed of the progress of events information very helpful to men under such a strain; but he well knew that these men would understand his action and cheerfully accept their
