"Is that Borkum?" asked Stirling of the sub-lieutenant, pointing to a low-lying island, apparently occupied by a few cottages on the side and a row of sandhills.
"Aye; looks harmless enough. Tucked away on the lee side of those dunes is a regular hornet's nest of torpedo craft. Batteries, too, everywhere, and jolly well masked."
"Don't you think it somewhat remarkable that a destroyer should be sent from Heligoland to watch the movements of my friend's yacht when Borkum is so much nearer?"
"I do; but questions have been asked and have been answered--after a fashion. The powers that be seem satisfied, and we have to accept the situation. It's galling, but----"
And with a deprecatory movement of his hand the sub-lieutenant hurried off to join his chief on the bridge.
"Ting-ting!" The bridge telegraph signalled to the engine-room for half-speed ahead. The _Boxer_ was nearing the shoals outlying the Frisian Islands.
"There she is!" exclaimed Mallet, removing his binoculars from his eyes and pointing almost dead over the bows. "That's S174."
The German destroyer was heading straight for the _Boxer_. In a very few minutes the two craft would be passing each other unless the German boat altered her course considerably.
In obedience to a sign from the lieutenant-commander, a seaman made his way aft to where the White Ensign floated proudly in the breeze. Uncleating the halyards he waited.
"Port your helm," came the order. Mallet, though loath to give way, was resolved to take no risks of collision. As the British destroyer swung away a point to starboard the German followed suit; then resuming their former course the two vessels swept past each other at a difference in speed of quite thirty-eight knots.
Slowly, almost defiantly, the Black Cross Ensign of S174 was lowered and quickly rehoisted. The compliment was smartly returned by the _Boxer_, and ere her White Ensign was hauled up to the truck the German vessel was observed to be circling to starboard.
"What's her game?" asked Mallet indignantly. "Surely she isn't going to follow us? At any rate she won't overhaul us if I can help it."
The lieutenant-commander's hand was on the bridge telegraph, ready to give the order for full-speed ahead, when the German destroyer shaped a course to the nor'-west. Her commander realized that his attempt to recapture the _Diomeda_ by a ruse or otherwise was a failure. Rather than see the yacht leave the Dollart under the convoy of a British warship he preferred to return to Heligoland.