In the study of his bungalow, all this time, Del Mar was striding angrily up and down, while his men waited in silence.

Finally he paused and turned to one of them.  “See that the coast is clear and kept clear,” he ordered.  “I want to go down.”

The man saluted and went out through the panel.  A moment later Del Mar gave some orders to the other man who also saluted and left the house by the front door, just as our car pulled up.

Del Mar, the moment the man was gone, put on his hat and moved toward the panel in the wall.  He was about to enter when he heard some one coming down the hall to the study and stepped back, closing the panel.  It was the butler announcing us.

We had entered Del Mar’s bungalow and now were conducted to his library.  There Elaine told him the whole story, much to his apparent surprise, for Del Mar was a wonderful actor.

“You see,” he said as she finished telling of the finding and the losing of the torpedo, “just what I had feared would happen has happened.  Doubtless the foreign agents have the deadly weapon, now.  However, I’ll not quit.  Perhaps we may run them down yet.”

He reassured us and we thanked him as we said good-bye.  Outside, Elaine and I got into the car again and a moment later spun off, making a little detour first through the country before hitting the shore road back again to Dodge Hall.

On the rocky shore of the promontory, several men were engaged in sinking a peculiar heavy disk which they submerged about ten or twelve feet.  It seemed to be held by a cable and to it wires were attached, apparently so that when a key was pressed a circuit was closed.

It was an “oscillator”, a new system for the employment of sound for submarine signalling, using water instead of air as a medium to transmit sound waves.  It was composed of a ring magnet, a copper tube lying in an air-gap in a magnetic field and a stationary central armature.  The tube was attached to a steel diaphragm.  Really it was a submarine bell which could be used for telegraphing or telephoning both ways through water.

The men finished executing the directions of Del Mar and left, carefully concealing the land connections and key of the bell, while we were still at Del Mar’s.

We had no sooner left, however, than one of the men who had been engaged in installing the submarine bell entered the library.

“Well?” demanded Del Mar.

“The bell is installed, sir,” he said.  “It will be working soon.”

“Good,” nodded Del Mar.

He went to a drawer and from it took a peculiar looking helmet to which was attached a sort of harness fitting over the shoulders and carrying a tank of oxygen.  The head-piece was a most weird contrivance, with what looked like a huge glass eye in front.  It was in reality a submarine life-saving apparatus.

Del Mar put it on, all except the helmet which he carried with him, and then, with his assistant, went out through the panel in the wall.  Through the underground passage the two groped their way, lighted by an electric torch, until at last they came to the entrance hidden in the underbrush, near the shore.