Another destroyer known as _D_ was also the target of a torpedo which passed it from starboard to port across the bow about forty yards ahead of the ship, leaving a perceptible wake visible for about four or five hundred yards. The submarine sighted by the flagship immediately engaged the attention of destroyer _B_. In fact it darted under the latter and passed the flagship's bows, disappearing close aboard on the flagship's port bow between the destroyer columns. The _B_ followed the wake between the columns and reported strong indications of two submarines astern, which grew fainter. The _B_ afterward guarded the rear of the convoy. So much for the ghostly movements of the submarine or submarines which crossed the tracks of the first contingent of American transports on the night of June 22. In the absence of more tangible proof of their presence beyond that provided by white streaks and wakes on the sea surface, the incident might well have been a false alarm. It only occasioned much excitement and activity. But its interest lay in the alertness of the destroyers to danger. The officers on board the flotilla had no doubt at all that the danger was real. Admiral Gleaves, indeed, saw circumstantial evidence of the menace in alluding to a bulletin of the French General Staff which referred to the activities of a German submarine off the Azores. This U-boat, the bulletin said, was ordered to watch in the vicinity of those islands, "at such a distance as it was supposed the enemy American convoy would pass from the Azores." The second contingent of transports, which arrived in France a week later, had a similar experience, with the important difference that their encounters with submarines took place in broad daylight, and that the firing at one of them produced material traces of the enemy's proximity. Two submarines were met on the morning of June 26, 1917, one at 11.30, when the ships were about a hundred miles off the coast of France, the other an hour later. The destroyer _H_, which was leading, sighted the first U-boat, and the _I_ pursued the wake, but without making any further discovery. The second episode was more convincing of the actual presence of a submarine. The destroyer _J_ saw the bow wave of one at a distance of 1,500 yards and headed for it at a rapid speed. The pointers at the destroyer's gun sighted its periscope several times for several seconds; but it disappeared each time before they could get their aim, which the zigzagging of the ship impeded. Presently the _J_ passed about twenty-five yards ahead of a mass of bubbles which obviously came from the submarine's wake. A deep charge was fired just ahead of these bubbles. Several pieces of timber, quantities of oil and debris then came to the surface. Nothing more was seen of the submarine. There was plain evidence that it had been sunk.