E16, of the Harwich Force, also had a fine record. Among other exploits, she sank a destroyer, she sank a German submarine, she sank an auxiliary cruiser; and finally she herself was numbered among those that did not come back. The submarines that were engaged in mine-laying also had an occasional successful fight with enemy ships. Thus E34, while returning from a mine-laying expedition, made a clever attack on an enemy submarine. The two ships were on the surface, coming towards each other. The British submarine was the first to sight the other. She dived and fired a torpedo, which struck the German in the conning-tower. A violent explosion followed, and afterwards there was nothing to be seen on the water save two objects, one of which proved to be the German captain, who was saved, and the other to be one of the crew, who sank. It is the practice of the submarine to deliver its attack when below the surface. There are, however, exceptions to this rule, as when the attack is made on a dark night, when it would be impossible to distinguish one's target through a periscope. Thus E52, of the Harwich Flotilla, in November 1917, while co-operating with the Dover Patrol, sighted an enemy submarine at about one o'clock in the morning; she attacked the enemy on the surface, and fired two torpedoes, both of which struck. The German sank, and only one survivor was picked up. And now and again it was bigger game that was brought down, as when E8, of the Harwich Flotilla, at the time detached for service in the Baltic, struck the German heavy cruiser _Prince Adalbert_ with a torpedo at eight hundred yards range. The torpedo must have caused an explosion in the German's magazine, for she was blown to pieces, and the submarine had to dive to prevent the falling fragments from injuring her.