Del Mar went over to the concealed station from which the submarine bell was sounded and pressed the key as a signal.  Then he adjusted the submarine helmet to his head and deliberately waded out into the water, further and further, up to his head, then deeper still.

As he disappeared into the water, his emissary turned and went back toward the shore road.

. . . . . . .

The ride around through the country and back to the shore, road from Del Mar’s was pleasant.  In fact it was always pleasant to be with Elaine, especially in a car.

We were spinning along at a fast clip when we came to a rocky part of the coast.  As we made a turn a sharp breeze took off my hat and whirled it far off the road and among the rocks of the shore.  Elaine shut down the engine, with a laugh at me, and we left the car by the road while we climbed down the rocks after the hat.

It had been carried into the water, close to shore and, still laughing, we clambered over the rocks.  Elaine insisted on getting it herself and in fact did get it.  She was just about to hand it to me, when something bobbed up in the water just in front of us.  She reached for it and fished it out.  It was a cylinder with air-tight caps on both ends, in one of which was a hook.

“What do you suppose it is?” she asked, looking it over as we made our way up the rocks again to the car.  “Where did it come from?”

We did not see a man standing by our car, but he saw us.  It was Del Mar’s man who had paused on his way to watch us.  As we approached he hid on the other side of the road.

By this time we had reached the car and opened the cylinder.  Inside was a note which read: 

     “Chief arrived safely.  Keep watch.”

“What does it mean?” repeated Elaine, mystified.

Neither of us could guess and I doubt whether we would have understood any better if we had seen a sinister face peering at us from behind a rock near-by, although doubtless the man knew what was in the tube and what it meant.

We climbed into the car and started again.  As we disappeared, the man came from behind the rocks and ran quickly up to the top of the hill.  There, from the bushes, he pulled out a peculiar instrument composed of a strange series of lenses and mirrors set up on a tripod.

Eagerly he placed the tripod, adjusting the lenses and mirrors in the sunlight.  Then he began working them, and it was apparent that he was flashing light beams, using a Morse code.  It was a heliograph.

Down the shore on the top of the next hill sat the man who had already given the signal with the handkerchief to those in the valley who were working on the mining of the bridge.  As he sat there, his eye caught the flash of the heliograph signal.  He sprang up and watched intently.  Rapidly he jotted down the message that was being flashed in the sunlight: