The night was perfectly dark and at first they were unable to make out an object upon the silent water.  But suddenly, to the left, there was a single brief flash of light; a second to the right; one forward and one astern; then other arrivals from the deep flashed a signal of their safe arrival.  Producing his small pocket flashlight, Lord Hastings did the same.

“Seven besides ourselves,” he muttered to himself.

Slowly now the submarines drew closer together until presently a voice from the bridge of one could be heard by all as Admiral Schuler addressed his captains.

“We shall submerge until our periscopes alone show,” he gave his orders.  “Then we shall proceed at full speed for the mouth of the Thames.”

“But mines?” protested a voice.

“The mines have been swept clear,” was the reply.  “A flotilla of mine sweepers have been busy since dark.  Now, heed these orders:  We shall keep as close together as possible.  Reaching the Thames, one submarine must lead the way.  I shall call for a volunteer.”

“Here, sir,” Lord Hastings spoke up before the other commanders had a chance.

The others also volunteered, but Admiral Schuler awarded the honor to the U-16.

“You spoke first,” he explained.  Then he continued:  “Unfortunately, we have been unable to learn the exact positions of the various British war vessels in the Thames, but we do know that there are many stationed there—­just how far up the river I cannot say.  However, once there we shall not return until we have sunk them.”

A subdued cheer ran across the water in the darkness.

“It is time to go,” said Admiral Schuler.  “I shall show the way to the Thames, when the U-16 will take the lead.  To your posts and follow me closely.”

He went below, and the other commanders did likewise.  A moment later the purr of machinery became audible aboard each vessel.  Each submerged until the tip of her periscope protruded above the water, and then they sped after the flagship into the darkness of the night.

Swiftly they went, for Admiral Schuler realized the value of haste.  He wished to make the raid and be out to sea again before the break of day.

Aboard the eight units of the submarine flotilla there was joy unrestrained.  The crews of each vessel had been taken into the confidence of their commanders by this time and the men aboard seven of the craft were eagerly awaiting the moment when they could strike a terrible blow at the British navy.  In view of the successes that had already attended the efforts of the German submersibles, there was little doubt in the hearts of the men that the present venture would be accomplished.

Even the three British sailors aboard the U-16 were cheerful, for although they did not realize the exact import of their mission, they knew Lord Hastings well enough to realize that he was acting in this manner only because there was some big duty to perform.  They were content to follow him blindly.