"There is only one explanation," he snarled.
"And that is?"
"That they have discovered the mine. My friend, we had better be leaving as soon as possible. It will not be good for us to be found in this vicinity."
At that very moment two boys were standing with horror-stricken eyes on the deck of the submarine. In his hands Rob held a peculiar looking cylinder of steel. From one end of it hung two severed wires. It was so weighted and balanced as to float a distance of about five feet under the surface of the water.
"If I hadn't found those wires and cut them," Rob said, in an awe-stricken voice.
But Merritt did not answer. He could only clasp his companion's hand. The realization of the fearfully narrow limit by which they had escaped death almost overcame him. The night was hot, but both boys shivered as if stricken with the ague. It was some minutes before they could give the alarm to those on shore. Then the rapid blowing of the whistle used by the submarine when on the surface signalled their companions.
Some fifteen minutes later two pale-faced, wild-eyed lads were explaining to an absorbed group the foiling of the diabolical plot against Uncle Sam's diving boat. It was not long after, that the submarine was rushing through the water for the nearest harbor.
"If we can arouse the police along the coast we may yet be able to capture the authors of this outrage," exclaimed the ensign, as at full speed the Peacemaker clove through the waters.
"Yes; it's hardly probable that they had as swift a boat as this," agreed Mr. Barr. "If we can get ashore ahead of them, we can cause a police net to be spread that they can scarcely break through."
But it was decreed that the fate of Berghoff and his companion should be a different one. Suddenly, off to port of the Peacemaker, the night was split by a roar and a red flash of flame.